Patent Application
20230333405
The present invention relates to an aerial image display system and an input system including the aerial image display system.
Recently, an aerial image display apparatus that displays an image in the air where no screen is present is disclosed, and utilization thereof as an input device capable of a touch operation on a video displayed in the air without touch on a display or screen for sales promotion having a high eye-catching effect is expected.
The input device capable of a touch operation on a video displayed in the air does not require touch on a screen and is preferable from a hygienic point of view. Therefore, utilization as an input device that is touched by many and unspecified persons or as an input device that is used in a medical setting is expected. In addition, the aerial image is inconspicuous from sides other than the front. Therefore, for example, in an automated teller machine (ATM), an effect of preventing peeking from the surroundings during input of passwords is expected.
For example, JP2018-092135A describes an optical imaging apparatus that forms a real image of a subject to be projected, the optical image formation apparatus including: a polarizer that allows transmission of P polarized light of a polarizing axis parallel to a reference direction and reflects S polarized light of the polarizing axis perpendicular to the reference direction; a first retardation element that converts the S polarized light into circularly polarized light or elliptically polarized light; a mirror that reflects the light transmitted through the first retardation element; a second retardation element that converts the P polarized light reflected from the mirror and transmitted through the first retardation element and the polarizer into circularly polarized light or elliptically polarized light; and a retroreflection plate retroreflects the light transmitted through the second retardation element.
In the optical imaging apparatus described in JP2018-092135A, light from the subject to be projected (light projection means) is converted into S polarized light to be incident into the polarizer, the S polarized light reflected from the polarizer is reflected from the mirror. The light is converted into P polarized light, transmits through the polarizer, and is reflected from the retroreflection plate. The light is converted into S polarized light and is reflected from the polarizer to the visible side. As a result, an image of the subject to be projected is displayed in the air.
In this optical imaging apparatus, the polarizer needs to be disposed non-parallel to the mirror and the retroreflection plate (refer to FIG. 2 and the like of JP2018-092135A). Therefore, there is a problem in that the size of the apparatus increases.
An object of the present invention is to provide a thin aerial image display system that can display an aerial image and an input device capable of a touch operation on a video displayed in the air without touch on a screen.
In order to achieve the object, the present invention has the following configurations.
According to the present invention, it is possible to provide a thin aerial image display system that can display an aerial image and an input device capable of a touch operation on a video displayed in the air without touch on a screen.
Hereinafter, the details of the present invention will be described. The following description regarding components has been made based on a representative embodiment of the present invention. However, the present invention is not limited to the embodiment. In the present specification, numerical ranges represented by “to” include numerical values before and after “to” as lower limit values and upper limit values. In addition, “orthogonal” or “parallel” regarding an angle represents a range of the exact angle±10°, and “the same” and “different” regarding angles can be determined based on whether or not a difference between the angles is less than 5°.
In the present specification, “slow axis” represents a direction in which a refractive index in a plane is the maximum.
In addition, visible light refers to light having a wavelength which can be observed by human eyes among electromagnetic waves and refers to light in a wavelength range of 380 to 780 nm.
<Aerial Image Display System>
An aerial image display system according to an embodiment of the present invention comprises:
a half mirror; and
a reflective member that is selected from the group consisting of a concave mirror, a Fresnel mirror, and a retroreflective member,
in which the reflective member includes a reflective polarizer, and
the reflective polarizer configures a reflecting surface of the reflective member.
An aerial image display system 10a shown in
The half mirror 12 is a semi-transmissive and semi-reflective half mirror that reflects a part of incident light and allows transmission of the remaining light.
The reflective member 14 is selected from the group consisting of a concave mirror, a Fresnel mirror, and a retroreflective member.
In addition, the reflective member 14 includes a reflective polarizer as a reflective layer, and allows transmission of light having one polarization state in incident light and reflects polarized light orthogonal to the polarized light. That is, the reflective member 14 is a semi-transmissive and semi-reflective reflective member that reflects a part of incident light and allows transmission of the remaining light.
Here, the polarized light components orthogonal to each other are polarized light components positioned on opposite sides of the Poincare sphere, for example, the north pole and the south pole of the Poincare sphere. Specifically, the polarized light components orthogonal to each other are right circularly polarized light and left circularly polarized light in terms of circularly polarized light and are linearly polarized light components orthogonal to each other in terms of linearly polarized light. The reflective polarizer in the reflective member 14 may be a reflective linear polarizer or may be a reflective circular polarizer.
The reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and a reflecting surface thereof is formed of a reflective polarizer to exhibit an action of focusing the reflected light in the air.
The configuration of the reflective member 14 will be described below in detail.
An action of the aerial image display system 10a will be described.
In the example shown in
In a case where the object O is irradiated with light, the light is reflected from a surface of the object O. In this case, as shown in
The circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14 again. In addition, the circularly polarized light reflected from the half mirror 12 is converted into circularly polarized light having an opposite turning direction, and thus is reflected from the reflective member 14 (reflective polarizer). In this case, for example, in a case where the reflective member 14 is a retroreflective member, a traveling direction of the light reflected from the reflective member 14 is parallel and opposite to a direction from the half mirror 12 toward the reflective member 14. Therefore, the light reflected from the reflective member 14 is collected. Accordingly, the light reflected from the reflective member 14 is incident into the half mirror 12, and a part of the incident light transmitted through the half mirror 12 is collected to be focused in the air.
This way, the light from the object O that is positioned on the depth side further than the aerial image display system 10a in a view from the user U is focused by the aerial image display system 10a on a space in front of the aerial image display system 10a. As a result, an aerial image V1 of the object O can be displayed on the space in front of the aerial image display system 10a. The aerial image V1 is a real image that is focused in the air.
In the example shown in
In this configuration, the polarized light component of a part of the light transmitted through the half mirror 12 in the light from the object O is reflected from the reflective member 14. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus the reflected light is collected. A part of the light reflected from the reflective member 14 is reflected from the half mirror 12. In this case, the light reflected from the half mirror 12 is converted into polarized light having a polarization state orthogonal thereto. The light reflected from the half mirror 12 is incident into the reflective member 14. The light reflected from the half mirror 12 is converted into polarized light having a polarization state orthogonal thereto, and thus transmits through the reflective member 14 (reflective polarizer). The light transmitted through the reflective member 14 is collected. Therefore, the light is focused on the space in front of the aerial image display system 10a (the user U side), and the aerial image V1 of the object O can be displayed.
Here, in the example shown in
In an aerial image display system 10b shown in
The image display apparatus 16 is a well-known image display apparatus (display). Examples of the image display apparatus include a liquid crystal display device, an organic electroluminescent display device, a light emitting diode (LED) display device, and a micro LED display device. In addition, in a case where the aerial image is a still image, the image display apparatus may be a photograph with a backlight, a printed material, or the like. In the following description, the organic electroluminescence display device will also be referred to as “OLED”. OLED is an abbreviation for “Organic Light Emitting Diode”.
The half mirror 12 and the reflective member 14 are disposed on a visible side of the image display apparatus 16. The half mirror 12 and the reflective member 14 are as described above.
An action of the aerial image display system 10b will be described.
The image display apparatus 16 emits light that forms an image. In this case, as shown in
The circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14 again. In addition, the circularly polarized light reflected from the half mirror 12 is converted into circularly polarized light having an opposite turning direction, and thus is reflected from the reflective member 14. In this case, for example, in a case where the reflective member 14 is a retroreflective member, a traveling direction of the light reflected from the reflective member 14 is parallel and opposite to a direction from the half mirror 12 toward the reflective member 14. Therefore, the light reflected from the reflective member 14 is collected. Accordingly, the light reflected from the reflective member 14 is incident into the half mirror 12, and a part of the incident light transmitted through the half mirror 12 is collected to be focused in the air.
This way, in the aerial image display system 10b, the light emitted from the image display apparatus 16 is focused on a space on the reflective member 14 side (downstream side) of the aerial image display system 10b. As a result, the aerial image V1 of the image displayed by the image display apparatus 16 can be displayed on the space on the downstream side of the aerial image display system 10b.
In the present invention, the downstream side is a downstream side in an optical path of an image displayed (emitted) from the image display apparatus 16.
In addition, in the example shown in
That is, in the example shown in
In the example shown in
In this configuration, the polarized light component of a part of the light transmitted through the half mirror 12 in the light from the image display apparatus 16 is reflected from the reflective member 14. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus the reflected light is collected. A part of the light reflected from the reflective member 14 is reflected from the half mirror 12. In this case, the light reflected from the half mirror 12 is converted into polarized light having a polarization state orthogonal thereto. The light reflected from the half mirror 12 is incident into the reflective member 14. The light reflected from the half mirror 12 is converted into polarized light having a polarization state orthogonal thereto, and thus transmits through the reflective member 14 (reflective polarizer). The light transmitted through the reflective member 14 is collected. Therefore, the light is focused on the space in front of the aerial image display system 10b (the user U side), and the aerial image V1 of the object O can be displayed.
Here, the aerial image display system according to the embodiment of the present invention may further include a polarization separating element that has a function of separating incident light into polarized light components orthogonal to each other.
In an aerial image display system 10c shown in
The polarization separating element 18 is an element that separates at least a part of the incident light into polarized light components orthogonal to each other. Here, the polarized light components orthogonal to each other are polarized light components positioned on opposite sides of the Poincare sphere, for example, the north pole and the south pole of the Poincare sphere. Specifically, the polarized light components orthogonal to each other are right circularly polarized light and left circularly polarized light in terms of circularly polarized light and are linearly polarized light components orthogonal to each other in terms of linearly polarized light.
The half mirror 12, the reflective member 14, and the polarization separating element 18 are disposed on the visible side of the image display apparatus 16. The half mirror 12, the reflective member 14, and the image display apparatus 16 are as described above.
This aerial image display system 10c displays two kinds of images as multiple images to be superimposed.
Among the two kinds of images, one image R is not reflected from the half mirror 12 and the reflective member 14, transmits through all of the half mirror 12, the reflective member 14, and the polarization separating element 18, and is observed by the user U (refer to an arrow of a broken line in
Another image V1 selectively transmits through the reflective member 14, is reflected from the half mirror 12, is selectively reflected from the reflective member 14, and is observed by the user U. That is, the image V1 has an optical path that reciprocates between the half mirror 12 and the reflective member 14 (refer to an arrow of a solid line in
Although described below, the optical paths of the non-floating image R and the aerial image V1 are divided by the separation of the polarized light by the polarization separating element 18.
When the superimposed image V2 is observed by the user U, among the non-floating image R and the aerial image V1 that are superimposed, the aerial image V1 is observed to be positioned on the front side. In other words, in the superimposed image V2 observed by the user U, the aerial image V1 is observed to float from the non-floating image R.
For example, for use in a car navigation system, for example, as conceptually shown in
As a result, in the observed superimposed image, the user U can recognize the map image and the additional information at a glance, and can accurately and rapidly necessary information for the user U.
Here, in the aerial image display system 10c, the image display apparatus 16 alternately displays the image for the non-floating image R and the image for the aerial image V1 by time-division. Alternatively, the image display apparatus 16 alternately arranges and displays the image for the non-floating image R and the image for the aerial image V1, for example, by space-division in a stripe shape.
In a case where the image display apparatus 16 performs the display by time-division, the polarization separating element 18 separates incident light into polarized light components orthogonal to each other by performing polarization conversion or absorption temporally alternately on the incident light. In a case where the image display apparatus 16 performs the display by space-division, the polarization separating element 18 separates incident light into polarized light components orthogonal to each other by performing polarization conversion or absorption spatially alternately, for example, in a stripe shape on the incident light.
In a case where the aerial image display system 10c performs the display by time-division, at a timing at which the non-floating image R is displayed, the polarization separating element 18 operates such that the polarized light that transmits through the half mirror 12 and the reflective member 14 without being reflected from the half mirror 12 and the reflective member 14 is finally emitted to the visible side, and the polarized light that is reflected and reciprocates once between the half mirror 12 and the reflective member 14 is finally absorbed or reflected not to be emitted to the visible side. On the other hand, at a position where the aerial image V1 is displayed, the polarization separating element 18 operates such that the polarized light that is reflected and reciprocates once between the half mirror 12 and the reflective member 14 is emitted to the visible side, and the polarized light that transmits through the half mirror 12 and the reflective member 14 without being reflected from the half mirror 12 and the reflective member 14 is absorbed or reflected not to be emitted to the visible side.
In addition, in a case where the aerial image display system 10c performs the display by space-division, at a position at which the non-floating image R is displayed, the polarization separating element 18 operates such that the polarized light that transmits through the half mirror 12 and the reflective member 14 without being reflected from the half mirror 12 and the reflective member 14 is finally emitted to the visible side, and the polarized light that is reflected and reciprocates once between the half mirror 12 and the reflective member 14 is finally absorbed or reflected not to be emitted to the visible side. On the other hand, at a position where the aerial image V1 is displayed, the polarization separating element 18 operates such that the polarized light that is reflected and reciprocates once between the half mirror 12 and the reflective member 14 is emitted to the visible side, and the polarized light that transmits through the half mirror 12 and the reflective member 14 without being reflected from the half mirror 12 and the reflective member 14 is absorbed or reflected not to be emitted to the visible side.
As a result, in the aerial image display system 10c, the image for displaying the non-floating image R can be prevented from being displayed as the aerial image, the image to be displayed as the aerial image V1 can be prevented from being displayed as the non-floating image, and the superimposed image where the image for the non-floating image R can be appropriately recognized as the non-floating image R and the image for the aerial image V1 can be appropriately recognized as the aerial image V1 can be displayed.
In the example shown in
In addition, in the example shown in
Hereinafter, a specific configuration of the aerial image display system according to the embodiment of the present invention will be described in more detail.
First, the aerial image display system that displays an aerial image shown in
An aerial image display system 10d shown in
The reflective member 14 of the aerial image display system 10d includes, as the reflective polarizer, a reflective circular polarizer that allows transmission of circularly polarized light having one turning direction and reflects circularly polarized light having another turning direction.
The absorptive linear polarizer 20 and the absorptive linear polarizer 26 are well-known absorptive linearly polarizing plates.
In addition, the retardation layer 22 and the retardation layer 24 are well-known retardation layers. As described below the retardation layer converts linearly polarized light into circularly polarized light or converts circularly polarized light into linearly polarized light, and thus is basically a ¼ wave plate.
An action of the aerial image display system 10d will be described.
The image display apparatus 16 emits light for an image (aerial image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 20 to be converted into linearly polarized light in one direction. In the example shown in the drawing, for example, the absorptive linear polarizer 20 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light is incident into the retardation layer 22. The retardation layer 22 converts the incident linearly polarized light into circularly polarized light. In the example shown in the drawing, for example, the retardation layer 22 converts the linearly polarized light in the up-down direction into right circularly polarized light.
The right circularly polarized light is incident into the reflective member 14 including the reflective circular polarizer. In the example shown in the drawing, the reflective member 14 (reflective circular polarizer) allows transmission of right circularly polarized light. Therefore, the right circularly polarized light incident into the reflective member 14 transmits through the half mirror 12 without being reflected.
This right circularly polarized light is incident into the half mirror 12, and a part of the incident light transmits through the half mirror 12. The right circularly polarized light transmitted through the half mirror 12 is incident into the absorptive circular polarizer 32. In the example shown in the drawing, the absorptive circular polarizer 32 absorbs right circularly polarized light. Therefore, the right circularly polarized light incident into the absorptive circular polarizer 32 is absorbed. Specifically, the absorptive circular polarizer 32 includes the retardation layer 24 and the absorptive linear polarizer 26, and the right circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light in the up-down direction by the retardation layer 24. The absorptive linear polarizer 26 absorbs the linearly polarized light in the up-down direction. Therefore, the linearly polarized light in the up-down direction is absorbed by the absorptive linear polarizer 26.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 is reflected from the half mirror 12. In this case, the right circularly polarized light is converted into left circularly polarized light by reflection.
The left circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14. In the example shown in the drawing, the reflective circular polarizer of the reflective member 14 allows transmission of right circularly polarized light and reflects left circularly polarized light. Therefore, the left circularly polarized light incident into the reflective member 14 is reflected. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus reflects light to collect the light. The left circularly polarized light reflected from the reflective member 14 is incident into the half mirror 12.
A part of the left circularly polarized light incident into the half mirror 12 is reflected to be converted into right circularly polarized light, transmits through the reflective member 14, and is incident into the retardation layer 22 to be converted into linearly polarized light in the up-down direction. This linearly polarized light transmits through the absorptive linear polarizer 20, and is absorbed by the surface or the like of the image display apparatus 16.
On the other hand, the remaining left circularly polarized light incident into the half mirror 12 transmits through the half mirror 12. The left circularly polarized light transmitted through the half mirror 12 is incident into the absorptive circular polarizer 32. The absorptive circular polarizer 32 absorbs right circularly polarized light, and thus allows transmission of left circularly polarized light. In the example shown in the drawing, the absorptive circular polarizer 32 includes the retardation layer 24 and the absorptive linear polarizer 26, and the left circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light in a direction orthogonal to in the up-down direction by the retardation layer 24 (a direction perpendicular to the paper plane; in the drawing, for convenience of description, indicated by an arrow in the left-right direction; in the following description, also referred to as linearly polarized light in a left-right direction). The absorptive linear polarizer 26 absorbs the linearly polarized light in the up-down direction. Therefore, the linearly polarized light in the left-right direction transmits through the absorptive linear polarizer 26.
As described above, in the aerial image display system 10d, only the light of the optical path for the aerial image V1 is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the non-floating image. As a result, the image displayed by the image display apparatus 16 can be displayed as the aerial image V 1.
In addition, as a preferable aspect, the aerial image display system 10d includes the absorptive circular polarizer 32 that is provided on the visible side further than the half mirror 12. By including the absorptive circular polarizer 32, stray light such as the right circularly polarized light component that is completely reflected from the half mirror 12 can be absorbed by the absorptive circular polarizer 32, and recognition of an unnecessary image caused by the stray light can be more reliably suppressed. In addition, external light is reflected from the surface of the aerial image display system 10d, and so-called glittering can be prevented.
In addition, in a preferable aspect, in the aerial image display system 10d, an absorption axis of the absorptive linear polarizer 20 and an absorption axis of the absorptive linear polarizer 26 are orthogonal to each other.
With the above-described configuration, stray light such as a polarized light component that is not completely reflected from the reflective member 14 can be further reduced, which is preferable. However, the present invention is not limited to the above-described configuration, and, for example, an aspect where the absorption axis of the absorptive linear polarizer 20 and the absorption axis of the absorptive linear polarizer 26 are parallel to each other can also be adopted.
In addition, in the aerial image display system 10d, it is preferable that a size of retardation of the retardation layer 22 and a size of retardation of the retardation layer 24 match with each other. In addition, it is preferable that wavelength dispersibility of the retardation layer 22 and wavelength dispersibility of the retardation layer 24 match with each other, and it is more preferable that both of the wavelength dispersibility of the retardation layer 22 and the wavelength dispersibility of the retardation layer 24 are reverse dispersibility. Here, the reverse dispersibility refers to a property in which, as the wavelength increases, a value of retardation at the wavelength increases.
With the above-described configuration, stray light such as a polarized light component that is not completely reflected from the reflective member 14 can be further reduced, which is preferable.
In addition, in the aerial image display system 10d, it is preferable that the respective members adhere to each other such that an air layer is not present between the respective members. In a case where the air layer is present, unnecessary reflection at an air interface between the respective members may occur, reflection of polarized light that is originally not to be reflected from the reflective polarizer may occur, or stray light may be caused. For example, in the aerial image display system 10d, the right circularly polarized light component that is not converted into left circularly polarized light during reflection from the half mirror 12 is incident into the reflective member 14 again, transmits through the reflective member 14, and travels toward the image display apparatus 16. This right circularly polarized light is reflected from the surface of the retardation layer 22 to be converted into left circularly polarized light. Next, the left circularly polarized light transmits through the reflective member 14, the half mirror 12, and the absorptive circular polarizer 32, and may be recognized by the user U as an unnecessary image.
In addition, due to the same reason, in the aerial image display system 10d, in a case where the air layer is present between the respective members, it is preferable to perform an antireflection treatment on the air-side surface of the member. For the antireflection treatment, various well-known methods such as a method bonding an AR film where a thin film having a specific refractive index and a specific film thickness or a method of bonding a moth eye film can be used.
As described above, regarding the reduction in reflection between the respective members, the same can be applied to each of aspects of
An aerial image display system 10e shown in
The reflective member 14 of the aerial image display system 10e includes, as the reflective polarizer, a reflective circular polarizer that allows transmission of circularly polarized light having one turning direction and reflects circularly polarized light having another turning direction.
An action of the aerial image display system 10e will be described.
The image display apparatus 16 emits light for an image (aerial image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 20 to be converted into linearly polarized light in one direction. In the example shown in the drawing, for example, the absorptive linear polarizer 20 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light transmits through the retardation layer 22 to be converted into circularly polarized light. In the example shown in the drawing, for example, the retardation layer 22 converts the linearly polarized light in the up-down direction into right circularly polarized light.
In a case where the right circularly polarized light is incident into the half mirror 12, a part of the light is reflected to be converted into left circularly polarized light, and is incident into the retardation layer 22 to be converted into linearly polarized light in a direction orthogonal to the up-down direction (direction perpendicular to the paper plane). This linearly polarized light is linearly polarized light in a direction where the light does not transmit through the absorptive linear polarizer 20, and thus is absorbed by the absorptive linear polarizer 20.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 transmits through the half mirror 12 and is incident into the reflective member 14. In the example shown in the drawing, the reflective member 14 reflects right circularly polarized light. Therefore, the right circularly polarized light incident into the reflective member 14 is reflected to be incident into the half mirror 12. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus reflects light to collect the light.
A part of the right circularly polarized light incident into the half mirror 12 is reflected. In this case, the right circularly polarized light is converted into left circularly polarized light by reflection.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 transmits through the half mirror 12. The right circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light by the retardation layer 22, transmits through the absorptive linear polarizer 20, and is absorbed by the surface or the like of the image display apparatus 16.
The left circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14. The reflective circular polarizer of the reflective member 14 reflects right circularly polarized light, and thus allows transmission of left circularly polarized light. The left circularly polarized light transmitted through the reflective member 14 is incident into the absorptive circular polarizer 32. The absorptive circular polarizer 32 allows transmission of circularly polarized light having the same turning direction as circularly polarized light that transmits through the reflective member 14 while converting the circularly polarized light into linearly polarized light. Accordingly, in the example shown in the drawing, the absorptive circular polarizer 32 allows transmission of left circularly polarized light. Specifically, the left circularly polarized light transmitted through the reflective member 14 is incident into the retardation layer 24. The retardation layer 24 converts the incident left circularly polarized light into linearly polarized light in the left-right direction. The linearly polarized light transmitted through the retardation layer 24 is incident into the absorptive linear polarizer 26. The absorptive linear polarizer 26 allows transmission of the linearly polarized light in the left-right direction. As a result, the absorptive circular polarizer 32 allows transmission of circularly polarized light having the same turning direction as circularly polarized light that transmits through the reflective member 14 while converting the circularly polarized light into linearly polarized light.
As described above, in the aerial image display system 10e, only the light of the optical path for the aerial image V1 is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the non-floating image. As a result, the image displayed by the image display apparatus 16 can be displayed as the aerial image V1.
In addition, as a preferable aspect, the aerial image display system 10e includes the absorptive circular polarizer 32 that is provided on the visible side further than the reflective member 14. By including the absorptive circular polarizer 32, stray light such as the right circularly polarized light component that is not completely reflected from the reflective member 14 can be absorbed by the absorptive circular polarizer 32, and recognition of an unnecessary image caused by the stray light can be more reliably suppressed. In addition, external light is reflected from the surface of the aerial image display system 10e, and so-called glittering can be prevented.
Here, in the aerial image display system 10e, it is preferable that the retardation layer 22 has reverse dispersibility. In a case where the retardation layer 22 has reverse dispersibility, the light incident into the reflective member 14 is converted into more ideal circularly polarized light, and stray light can be further reduced, which is preferable.
Due to the same reason, it is also preferable that the retardation layer 24 has reverse dispersibility.
Next, a specific configuration of the aerial image display system that displays the superimposed image of the non-floating image and the aerial image shown in
An aerial image display system 10f shown in
In addition, in the example shown in the drawing, the polarization separating element 18 includes an absorptive linear polarizer 28 and a retardation layer 30. Although described below in detail, the polarization separating element 18 is any one of: a combination in which the absorptive linear polarizer 28 is any one of an active polarizer that is capable of switching a direction of a transmission axis (absorption axis) or a patterned polarizer that includes a plurality of regions having different directions of transmission axes (absorption axes) and the retardation layer 30 is a typical retardation layer; or a combination in which the retardation layer 30 is any one of an active retardation layer that is capable of switching a direction of a slow axis or a size of retardation or a patterned retardation layer that includes a plurality of regions having different directions of slow axes or different sizes of retardation and the absorptive linear polarizer 28 is a typical absorptive linear polarizer.
In a case where the polarization separating element 18 is the active polarizer or the active retardation layer, the polarization separating element 18 can switch between a state where, in incident light, transmission of one polarized light is allowed and polarized light orthogonal to the one polarized light is absorbed and a state where transmission of the orthogonal polarized light is allowed and the one polarized light is absorbed. Hereinafter, the polarization separating element 18 will also be referred to as “time-division polarization separating element 18”.
In a case where the polarization separating element 18 is the time-division polarization separating element 18, the image display apparatus 16 alternately displays the non-floating image R and the aerial image V1 by time-division according to the switching operation of the polarization separating element 18.
In the aerial image display system, at a timing at which the non-floating image R is displayed, the image display apparatus 16 displays only the non-floating image R by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the non-floating image R and does not allow transmission of polarized light passing through the optical path for the aerial image V1, and at a timing at which the aerial image V1 is displayed, the image display apparatus 16 displays only the aerial image V1 by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the aerial image V1 and does not allow transmission of polarized light passing through the optical path for the non-floating image R. The aerial image display system 10f displays the superimposed image V2 where the non-floating image R and the aerial image V1 are superimposed on each other by alternately displaying the non-floating image R and the aerial image V1.
In addition, in a case where the polarization separating element 18 is the patterned polarizer or the patterned retardation layer, the polarization separating element 18 includes a plurality of regions where, in incident light, transmission of one polarized light is allowed and polarized light orthogonal to the one polarized light is absorbed and regions where transmission of the orthogonal polarized light is allowed and the one polarized light is absorbed. Hereinafter, the polarization separating element 18 will also be referred to as “space-division polarization separating element 18”.
In a case where the polarization separating element 18 is the space-division polarization separating element 18, the image display apparatus 16 displays the non-floating image R and the aerial image V1 by space-division according to the configuration of the region division of the polarization separating element 18. For example, in a case where the polarization separating element 18 includes a region where transmission of one polarized light is allowed and a region where transmission of another polarized light is allowed alternately in a stripe shape, the image display apparatus 16 alternately arranges and displays the non-floating image R and the aerial image V1 by space-division in a stripe shape.
In the aerial image display system, in the region where the non-floating image R is displayed, the image display apparatus 16 displays only the non-floating image R by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the non-floating image R and does not allow transmission of polarized light passing through the optical path for the aerial image V1, and in the region where the aerial image V1 is displayed, the image display apparatus 16 displays only the aerial image V1 by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the aerial image V1 and does not allow transmission of polarized light passing through the optical path for the non-floating image R. The aerial image display system 10f displays the superimposed image V2 where the non-floating image R and the aerial image V1 are superimposed on each other by displaying the non-floating image R and the aerial image V1 in the respective regions.
In the example shown in
An action of the aerial image display system 10f in the state will be described.
The image display apparatus 16 emits light for an image (aerial image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 20 to be converted into linearly polarized light in one direction. In the example shown in the drawing, for example, the absorptive linear polarizer 20 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light is incident into the retardation layer 22. The retardation layer 22 converts the incident linearly polarized light into circularly polarized light. In the example shown in the drawing, for example, the retardation layer 22 converts the linearly polarized light in the up-down direction into right circularly polarized light.
The right circularly polarized light is incident into the reflective member 14. In the example shown in the drawing, the reflective circular polarizer of the reflective member 14 allows transmission of right circularly polarized light and reflects left circularly polarized light. Therefore, the right circularly polarized light incident into the reflective member 14 transmits through the half mirror 12 without being reflected.
This right circularly polarized light is incident into the half mirror 12, and a part of the incident light transmits through the half mirror 12. The right circularly polarized light transmitted through the half mirror 12 is incident into the polarization separating element 18. In the example shown in the drawing, the polarization separating element 18 absorbs right circularly polarized light. Therefore, the right circularly polarized light incident into the polarization separating element 18 is absorbed. Specifically, the polarization separating element 18 includes the retardation layer 30 and the absorptive linear polarizer 28, and the right circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light in the up-down direction by the retardation layer 30. The absorptive linear polarizer 28 absorbs the linearly polarized light in the up-down direction. Therefore, the linearly polarized light in the up-down direction is absorbed by the absorptive linear polarizer 28.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 is reflected from the half mirror 12. In this case, the right circularly polarized light is converted into left circularly polarized light by reflection.
The left circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14. In the example shown in the drawing, the reflective circular polarizer of the reflective member 14 reflects left circularly polarized light. Therefore, the left circularly polarized light incident into the reflective member 14 is reflected. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus reflects light to collect the light. The left circularly polarized light reflected from the reflective member 14 is incident into the half mirror 12.
A part of the left circularly polarized light incident into the half mirror 12 is reflected to be converted into right circularly polarized light, and is incident into the reflective member 14. This right circularly polarized light transmits through the reflective member 14, is converted into linearly polarized light by the retardation layer 22, transmits through the absorptive linear polarizer 20, and is absorbed by the surface or the like of the image display apparatus 16.
On the other hand, the remaining light of the left circularly polarized light incident into the half mirror 12 transmits through the half mirror 12. The left circularly polarized light transmitted through the half mirror 12 is incident into the polarization separating element 18. The polarization separating element 18 absorbs right circularly polarized light, and thus allows transmission of left circularly polarized light. In the example shown in the drawing, the polarization separating element 18 includes the retardation layer 30 and the absorptive linear polarizer 28, and the left circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light in the left-right direction by the retardation layer 30. The absorptive linear polarizer 28 absorbs the linearly polarized light in the up-down direction. Therefore, the linearly polarized light in the left-right direction transmits through the absorptive linear polarizer 28.
As described above, in the aerial image display system 10f, only the light of the optical path for the aerial image V1 is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the non-floating image. As a result, the image displayed by the image display apparatus 16 can be displayed as the aerial image V 1.
In the aerial image display system 10f, it is preferable that the retardation layer 22 has reverse dispersibility. In a case where the retardation layer 22 has reverse dispersibility, the light incident into the reflective member 14 is converted into more ideal circularly polarized light, and stray light can be further reduced, which is preferable.
In addition, due to the same reason, it is also preferable that the retardation layer 30 has reverse dispersibility.
On the other hand, in the example shown in
An action of the aerial image display system 10f in the state will be described.
The image display apparatus 16 emits light for an image (non-floating image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 20 to be converted into linearly polarized light in one direction. As described above, in the example shown in the drawing, for example, the absorptive linear polarizer 20 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light is incident into the retardation layer 22. The retardation layer 22 converts the incident linearly polarized light into circularly polarized light. As described above, in the example shown in the drawing, for example, the retardation layer 22 converts the linearly polarized light in the up-down direction into right circularly polarized light.
The right circularly polarized light is incident into the reflective member 14. In the example shown in the drawing, the reflective circular polarizer of the reflective member 14 allows transmission of right circularly polarized light and reflects left circularly polarized light. Therefore, the right circularly polarized light incident into the reflective member 14 transmits through the half mirror 12 without being reflected.
This right circularly polarized light is incident into the half mirror 12, and a part of the incident light transmits through the half mirror 12. The right circularly polarized light transmitted through the half mirror 12 is incident into the polarization separating element 18. In the example shown in the drawing, the polarization separating element 18 allows transmission of right circularly polarized light. Therefore, the right circularly polarized light transmits through the polarization separating element 18 and is emitted from the aerial image display system 10f. In the example shown in the drawing, the right circularly polarized light transmits through the retardation layer 30 of the polarization separating element 18 to be converted into linearly polarized light in the left-right direction. That is, in
On the other hand, a part of the right circularly polarized light reflected from the half mirror 12 is converted into left circularly polarized light by reflection. The left circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14. The reflective circular polarizer of the reflective member 14 allows transmission of right circularly polarized light and reflects left circularly polarized light. Therefore, this left circularly polarized light is reflected. The reflected left circularly polarized light is incident into the half mirror 12.
A part of the light incident into the half mirror 12 transmits through the half mirror 12. The transmitted left circularly polarized light is incident into the polarization separating element 18. The polarization separating element 18 allows transmission of right circularly polarized light, and thus absorbs left circularly polarized light. Specifically, the left circularly polarized light transmits through the retardation layer 30 of the polarization separating element 18 and is converted into linearly polarized light in the up-down direction. The absorptive linear polarizer 28 absorbs the linearly polarized light in the up-down direction. Therefore, the linearly polarized light in the up-down direction is absorbed by the absorptive linear polarizer 28.
On the other hand, the left circularly polarized light reflected from the half mirror 12 is converted into right circularly polarized light by reflection, transmits through the reflective member 14, is converted into linearly polarized light by the retardation layer 22, transmits through the absorptive linear polarizer 20, and is absorbed by the surface or the like of the image display apparatus 16.
As described above, at the timing at which the aerial image display system 10f displays the non-floating image R or in the region where the aerial image display system 10f displays the non-floating image R, only the light of the optical path for the non-floating image R is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the aerial image. As a result, in the image display apparatus 16, the image to be displayed as the non-floating image R can be prevented from being displayed as the aerial image, and only the non-floating image R can be displayed.
In the aerial image display system 10f, at the timing at which or in the region where the non-floating image R is displayed, the image display apparatus 16 displays only the non-floating image R by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the non-floating image R and does not allow transmission of polarized light passing through the optical path for the aerial image V1, and at the timing at which or in the region where the aerial image V1 is displayed, the image display apparatus 16 displays only the aerial image V1 by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the aerial image V1 and does not allow transmission of polarized light passing through the optical path for the non-floating image R. The aerial image display system 10f displays the superimposed image V2 where the non-floating image R and the aerial image V1 are superimposed on each other by displaying the non-floating image R and the aerial image V1 by time-division or space-division.
In the example shown in
An aerial image display system 10g shown in
In the example shown in
An action of the aerial image display system 10g in the state will be described.
The image display apparatus 16 emits light for an image (aerial image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 28 of the polarization separating element 18 to be converted into linearly polarized light in one direction. In the example shown in the drawing, for example, the absorptive linear polarizer 28 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light transmits through the retardation layer 30 of the polarization separating element 18 to be converted into circularly polarized light. In the example shown in the drawing, for example, the retardation layer 30 converts the linearly polarized light in the up-down direction into right circularly polarized light.
In a case where the right circularly polarized light is incident into the half mirror 12, a part of the light is reflected to be converted into left circularly polarized light, and is incident into the retardation layer 30 to be converted into linearly polarized light in the left-right direction. This linearly polarized light is linearly polarized light in a direction where the light does not transmit through the absorptive linear polarizer 28, and thus is absorbed by the absorptive linear polarizer 28.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 transmits through the half mirror 12 and is incident into the reflective member 14. In the example shown in the drawing, the reflective circular polarizer of the reflective member 14 reflects right circularly polarized light. Therefore, the right circularly polarized light incident into the reflective member 14 is reflected to be incident into the half mirror 12. In addition, the reflective member 14 is any one of a concave mirror, a Fresnel mirror, or a retroreflective member, and thus reflects light to collect the light.
A part of the light incident into the half mirror 12 is reflected. In this case, the right circularly polarized light is converted into left circularly polarized light by reflection.
On the other hand, the remaining light of the right circularly polarized light incident into the half mirror 12 transmits through the half mirror 12. The right circularly polarized light transmitted through the half mirror 12 is converted into linearly polarized light by the retardation layer 30, transmits through the absorptive linear polarizer 28, and is absorbed by the surface or the like of the image display apparatus 16.
The left circularly polarized light reflected from the half mirror 12 is incident into the reflective member 14. The reflective circular polarizer of the reflective member 14 reflects right circularly polarized light, and thus allows transmission of left circularly polarized light. The left circularly polarized light transmitted through the reflective member 14 is incident into the absorptive circular polarizer 32. The absorptive circular polarizer 32 allows transmission of circularly polarized light having the same turning direction as circularly polarized light that transmits through the reflective member 14 while converting the circularly polarized light into linearly polarized light. Accordingly, in the example shown in the drawing, the absorptive circular polarizer 32 allows transmission of left circularly polarized light. Specifically, the left circularly polarized light transmitted through the reflective member 14 is incident into the retardation layer 24. The retardation layer 24 converts the incident left circularly polarized light into linearly polarized light in the left-right direction. The linearly polarized light transmitted through the retardation layer 24 is incident into the absorptive linear polarizer 26. The absorptive linear polarizer 26 allows transmission of the linearly polarized light in the left-right direction. As a result, the absorptive circular polarizer 32 allows transmission of circularly polarized light having the same turning direction as circularly polarized light that transmits through the reflective member 14 while converting the circularly polarized light into linearly polarized light.
As described above, in the aerial image display system 10g, at the timing at which the image display apparatus 16 displays the aerial image V1 or in the region where the image display apparatus 16 displays the aerial image V1, only the light of the optical path for the aerial image V1 is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the non-floating image. As a result, in the image display apparatus 16, the image to be displayed as the aerial image V1 can be prevented from being displayed as the non-floating image, and only the aerial image V1 can be displayed.
In addition, as a preferable aspect, the aerial image display system 10g includes the absorptive circular polarizer 32 that is provided on the visible side further than the reflective member 14. By including the absorptive circular polarizer 32, stray light such as the right circularly polarized light component that is not completely reflected from the reflective member 14 can be absorbed by the absorptive circular polarizer 32, and recognition of an unnecessary image caused by the stray light can be more reliably suppressed. In addition, external light is reflected from the surface of the aerial image display system 10g, and so-called glittering can be prevented.
Here, in the aerial image display system 10g, it is preferable that the retardation layer 30 has reverse dispersibility. In a case where the retardation layer 30 has reverse dispersibility, the light incident into the reflective member 14 is converted into more ideal circularly polarized light, and stray light can be further reduced, which is preferable.
Due to the same reason, it is also preferable that the retardation layer 24 has reverse dispersibility.
On the other hand, in the example shown in
An action of the aerial image display system 10g in the state will be described.
The image display apparatus 16 emits light for an image (non-floating image). In this case, as described above, light is emitted from each of points (each of pixels) on the image display apparatus toward various directions. The light emitted from the image display apparatus 16 transmits through the absorptive linear polarizer 28 of the polarization separating element 18 to be converted into linearly polarized light in one direction. In the example shown in the drawing, for example, the absorptive linear polarizer 28 allows transmission of linearly polarized light in an up-down direction in the drawing. Next, this linearly polarized light transmits through the retardation layer 30 of the polarization separating element 18 to be converted into circularly polarized light. In the example shown in the drawing, for example, the retardation layer 30 converts the linearly polarized light in the up-down direction into left circularly polarized light. That is, in
In a case where the left circularly polarized light is incident into the half mirror 12, a part of the light is reflected to be converted into right circularly polarized light, and is incident into the retardation layer 30 to be converted into linearly polarized light in the left-right direction. This linearly polarized light is linearly polarized light in a direction where the light does not transmit through the absorptive linear polarizer 28, and thus is absorbed by the absorptive linear polarizer 28.
On the other hand, the remaining light of the left circularly polarized light incident into the half mirror 12 transmits through the half mirror 12 and is incident into the reflective member 14. The incident light is circularly polarized light having a turning direction opposite to that of the circularly polarized light reflected from the reflective circular polarizer of the reflective member 14, and thus transmits through the reflective member 14.
The left circularly polarized light transmitted through the reflective member 14 is incident into the absorptive circular polarizer 32. As described above, the absorptive circular polarizer 32 converts the incident left circularly polarized light into linearly polarized light in the left-right direction and allows transmission of the light.
As described above, at the timing at which the aerial image display system 10g displays the non-floating image R or in the region where the aerial image display system 10g displays the non-floating image R, only the light of the optical path for the non-floating image R is emitted to the user U side, and the image displayed by the image display apparatus 16 is prevented from being recognized as the aerial image. As a result, in the image display apparatus 16, the image to be displayed as the non-floating image R can be prevented from being displayed as the aerial image, and only the non-floating image R can be displayed.
In the aerial image display system 10g, at the timing at which or in the region where the non-floating image R is displayed, the image display apparatus 16 displays only the non-floating image R by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the non-floating image R and does not allow transmission of polarized light passing through the optical path for the aerial image V1, and at the timing at which or in the region where the aerial image V1 is displayed, the image display apparatus 16 displays only the aerial image V1 by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the aerial image V1 and does not allow transmission of polarized light passing through the optical path for the non-floating image R. The aerial image display system 10g displays the superimposed image V2 where the non-floating image R and the aerial image V1 are superimposed on each other by displaying the non-floating image R and the aerial image V1 by time-division or space-division.
In the example shown in
In addition, in the example shown in
Next, the components of the aerial image display system will be described.
(Half Mirror)
The half mirror is a well-known half mirror in the related art that allows transmission of about half of incident light and reflects the remaining half of the incident light. The transmittance of the half mirror is preferably 50±30%, more preferably 50±10%, and most preferably 50%. The half mirror has a configuration in which, for example, a reflective layer formed of a metal such as silver or aluminum is provided on a substrate formed of a transparent resin such as polyethylene terephthalate (PET), a cycloolefin polymer (COP), or polymethyl methacrylate (PMMA), glass, or the like. The reflective layer formed of a metal such as silver or aluminum is formed on a surface of the substrate by vapor deposition or the like. The thickness of the reflective layer is preferably 1 to 20 nm, more preferably 2 to 10 nm, and still more preferably 3 to 6 nm.
(Reflective Member)
The reflective member includes a reflective polarizer, and the reflective polarizer forms a reflecting surface of the reflective member and allows transmission of light having one polarization state in incident light and reflects polarized light orthogonal to the polarized light.
In addition, the reflective member is selected from the group consisting of a concave mirror, a Fresnel mirror, and a retroreflective member.
Each of
A reflective member 14a shown in
The support 40a is formed of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonates, polyvinyl chloride, acryl, or polyolefin, and one surface (concave surface) has a concave portion obtained by cutting out a part of a spherical surface or a paraboloidal surface.
The reflective polarizer 42a is laminated on the concave surface of the support 40a.
The reflective polarizer 42a is laminated along the concave portion of the support 40a with a substantially fixed thickness. That is, the reflective polarizer 42a has a shape that is curved in a concave shape.
Due to the reflective polarizer 42a, the reflective member 14a allows transmission of light having one polarization state and reflects polarized light having a polarization state orthogonal to the polarized light. In addition, the reflective polarizer 42a has a concave shape to have a function of collecting the reflected light.
The reflective polarizer is not particularly limited, and various reflective polarizers can be used.
The reflective polarizer is basically a reflective linear polarizer or a reflective circular polarizer.
The reflective linear polarizer is a polarizer that allows transmission of linearly polarized light in one direction and reflects linearly polarized light in a direction orthogonal to the linearly polarized light.
Examples of the reflective linear polarizer include a film obtained by stretching a dielectric multi-layer film described in JP2011-053705A and a wire grid polarizer described in JP2015-028656A. In addition, as the reflective linear polarizer, a commercially available product can be suitably used. Examples of the reflective linear polarizer as the commercially available product include a reflective polarizer (trade name: APF) manufactured by 3M and a wire grid polarizer (trade name: WGF) manufactured by Asahi Kasei Corporation.
The reflective circular polarizer is a polarizer that allows transmission of right circularly polarized light and left circularly polarized light and reflects circularly polarized light having a turning direction opposite to that of the transmitted circularly polarized light.
Examples of the reflective circular polarizer include a reflective circular polarizer including a cholesteric liquid crystal layer. The cholesteric liquid crystal layer is a liquid crystal layer obtained by immobilizing a cholesterically aligned liquid crystal phase (cholesteric liquid crystalline phase).
As is well known, the cholesteric liquid crystal layer has a helical structure in which the liquid crystal compound is helically turned and laminated. In the helical structure, a configuration in which the liquid crystal compound is helically rotated once (rotated by 360°) and laminated is set as one helical pitch (helical pitch), and plural pitches of the helically turned liquid crystal compounds are laminated.
The cholesteric liquid crystal layer reflects left circularly polarized light or right circularly polarized light in a specific wavelength range and allows transmission of the other light depending on the length of the helical pitch and the helical turning direction (sense) of the liquid crystal compound.
Accordingly, in a case where the aerial image display system displays a color image, the reflective circular polarizer may include, for example, a plurality of cholesteric liquid crystal layers including a cholesteric liquid crystal layer that has a central wavelength of selective reflection for red light, a cholesteric liquid crystal layer that has a central wavelength of selective reflection for green light, and a cholesteric liquid crystal layer that has a central wavelength of selective reflection for blue light.
In addition, the cholesteric liquid crystal layer may be directly formed on the support 40a having the concave surface, or may be formed on the concave surface of the support 40a after being formed on a temporary support. In addition, an alignment film for aligning a liquid crystal compound in the cholesteric liquid crystal layer may be provided between the support 40a and the cholesteric liquid crystal layer.
The thickness of the reflective polarizer may be appropriately adjusted depending on the kind of the reflective polarizer and the like such that polarized light to be reflected can be sufficiently reflected and polarized light to be transmitted can be sufficiently transmitted.
In addition, in a preferable aspect, the reflective member 14a in the example shown in the drawing includes the coating layer 44a that is laminated on a surface of the reflective polarizer 42a opposite to the support 40a. It is preferable that the coating layer 44a is transparent. In addition, it is preferable that the coating layer 44a is formed of a material having substantially the same refractive index as the support 40a. Further, it is preferable that a surface of the support 40a opposite to the reflective polarizer 42a and a surface of the coating layer 44a opposite to the reflective polarizer 42a are flat surfaces parallel to each other.
In a case where the coating layer 44a is not provided, light transmitted through the reflective member is bent due to the influence of the concave surface of the support 40a. Therefore, an image of the light transmitted through the reflective member undergoes an enlargement or reduction action.
On the other hand, the reflective member 14a includes the coating layer 44a having substantially the same refractive index as the support 40a, and the surfaces of the support 40a and the coating layer 44a are flat surfaces parallel to each other. As a result, light transmitted through the reflective member 14a can be prevented from being bent due to the influence of the concave surface of the support 40a, and an image of the light transmitted through the reflective member 14a can be prevented from undergoing the enlargement or reduction action. As a result, in the aerial image display system according to the embodiment of the present invention, the non-floating image and/or the aerial image can be prevented from being enlarged or reduced or from being distorted.
The refractive index of the support 40a and the refractive index of the coating layer 44a do not need to be exactly the same as long as the above-described effect can be obtained, and may have a difference within a range where the effect can be obtained. The difference between the refractive index of the support 40a and the refractive index of the coating layer 44a is preferably 0.1 or less, more preferably 0.05 or less, and still more preferably 0.01 or less.
A reflective member 14b shown in
As shown in
The support 40b is formed of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonates, polyvinyl chloride, acryl, or polyolefin, and includes a well-known corner cube array as the retroreflective member.
The reflective polarizer 42b is laminated on the corner cube array of the support 40b.
The reflective polarizer 42b is laminated along the surface shape of the corner cube array of the support 40b with a substantially fixed thickness. That is, the reflective polarizer 42b functions as the reflective layer of the corner cube array. The reflective polarizer 42b is a well-known reflective circular polarizer or reflective linear polarizer in the related art as in the reflective polarizer 42a of the reflective member 14a, except that the shape is different.
Due to the reflective polarizer 42a, the reflective member 14a allows transmission of light having one polarization state and reflects polarized light having a polarization state orthogonal to the polarized light, and has a function of retroreflecting reflected light.
In addition, in a preferable aspect, the reflective member 14b in the example shown in the drawing also includes the coating layer 44b that is laminated on a surface of the reflective polarizer 42b opposite to the support 40b. The surface of the support 40b opposite to the reflective polarizer 42b and the surface of the coating layer 44b opposite to the reflective polarizer 42b are flat surfaces parallel to each other. It is preferable that the coating layer 44b is transparent, and the difference between the refractive index of the support 40b and the refractive index of the coating layer 44b is preferably 0.1 or less, more preferably 0.05 or less, and still more preferably 0.01 or less.
In the example shown in the drawing, the reflective member 14b is the retroreflective member that is formed of the corner cube array. However, the present invention is not limited to this example. In the glass bead type retroreflective member, the reflecting surface may be a reflective polarizer.
A reflective member 14c shown in
The support 40c is formed of glass, triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonates, polyvinyl chloride, acryl, or polyolefin, and one surface has a well-known Fresnel lens shape.
The reflective polarizer 42c is laminated on a surface of the support 40c where the groove having a Fresnel lens shape is formed.
The reflective polarizer 42c is laminated along the Fresnel lens shape of the support 40a with a substantially fixed thickness. That is, the reflective polarizer 42c has a Fresnel lens shape. The reflective polarizer 42c is a well-known reflective circular polarizer or reflective linear polarizer in the related art as in the reflective polarizer 42a of the reflective member 14a, except that the shape is different.
Due to the reflective polarizer 42c, the reflective member 14c allows transmission of light having one polarization state and reflects polarized light having a polarization state orthogonal to the polarized light. In addition, the reflective polarizer 42c has a Fresnel lens shape to function as a Fresnel mirror, and has a function of collecting reflected light due to the same action of the concave mirror.
In addition, in a preferable aspect, the reflective member 14c in the example shown in the drawing also includes the coating layer 44c that is laminated on a surface of the reflective polarizer 42c opposite to the support 40c. The surface of the support 40c opposite to the reflective polarizer 42c and the surface of the coating layer 44c opposite to the reflective polarizer 42c are flat surfaces parallel to each other. It is preferable that the coating layer 44c is transparent, and the difference between the refractive index of the support 40c and the refractive index of the coating layer 44c is preferably 0.1 or less, more preferably 0.05 or less, and still more preferably 0.01 or less.
(Polarization Separating Element)
The polarization separating element is an element that has a function of separating at least a part of the incident light into polarized light components orthogonal to each other. For example, the polarization separating element separates the incident light into right circularly polarized light and left circularly polarized light or into linearly polarized light components having orthogonal to each other.
As described above, it is preferable that the polarization separating element includes any one of an active retardation layer, a patterned retardation layer, an active polarizer, or a patterned polarizer.
The active retardation layer is a retardation layer that is capable of switching a direction of a slow axis or a size of retardation.
As the active retardation layer capable of switching a direction of a slow axis, various well-known retardation layers can be used. Examples of the active retardation layer include an active retardation layer that is capable of switching a voltage to be applied to switch a direction of a slow axis (optical axis of a liquid crystal compound) to a direction orthogonal to the direction using a liquid crystal cell that acts as a ¼ wave plate, for example, as in an active shutter stereoscopic image display apparatus.
In addition, as the active retardation layer that is capable of switching a size of retardation, various well-known retardation layers can be used. Examples of the active retardation layer include an active retardation layer that is capable of switching a voltage to be applied to switch between, for example, a state where the retardation is zero and a state where the retardation is ½ wavelength using a liquid crystal cell such as a vertical alignment (VA) type.
In the present invention, the ¼ wave plate (¼ wave retardation plate) is a retardation plate having a retardation of about ¼ wavelength at any wavelength of visible light.
As the ¼ wave plate, for example, at a wavelength of 550 nm, a ¼ wave plate having a retardation of 120 nm to 150 nm is preferable, and a ¼ wave plate having a retardation of 130 nm to 140 nm is more preferable.
The patterned retardation layer includes a plurality of regions having different directions of slow axes and/or different sizes of retardation.
Examples of the patterned retardation layer having different directions of slow axes include a patterned retardation layer that is a ¼ wave plate and is divided into regions in a stripe shape and where directions of slow axes in adjacent regions are orthogonal to each other. In addition, examples of the patterned retardation layer having different sizes of retardation include a patterned retardation layer that is divided into regions in a stripe shape and where a region having a retardation of ¼ wavelength and a region having a retardation of ¾ wavelength are alternately formed.
The patterned retardation layer may be prepared using a well-known method such as a method described in JP2012-008170A, a method described in JP2012-032661A, or the like. In addition, as the patterned retardation layer, a commercially available product can also be used.
In the above-described example, the active retardation layer capable of switching a direction of a slow axis and the patterned retardation layer that includes a plurality of regions having different directions of slow axes are described as representative examples. However, even an active retardation layer that is capable of switching a size of retardation and a patterned retardation layer that includes a plurality of regions having different sizes of retardation can exhibit the same effects.
The active polarizer is a polarizer that is capable of switching a direction of a transmission axis or an absorption axis. The active polarizer switches, for example, a direction of absorption axis (transmission axis) between two directions orthogonal to each other.
As the active polarizer, various well-known polarizers can be used. Examples of the active polarizer include an active polarizer that changes an alignment direction of a dichroic coloring agent as described in JP2019-70781A by interposing a guest-host liquid crystal layer having a dichroic coloring agent between a pair of opposing electrode layers and applying a voltage thereto.
The patterned polarizer is a polarizer that includes a plurality of regions having different directions of transmission axes or absorption axes. Examples of the patterned polarizer include a patterned retardation layer that is divided into regions in a stripe shape and where directions of transmission axes (absorption axes) in adjacent regions are orthogonal to each other.
As the patterned polarizer, for example, a patterned retardation layer various well-known polarizers such as a patterned polarizer that includes two or more regions having different directions of absorption axes as described in JP2009-193014A can be used.
In the patterned retardation layer and the patterned polarizer, the pattern of the regions is not limited to a stripe shape.
As the pattern that can be used in the patterned retardation layer, for example, a checkered pattern can also be used in addition to a stripe pattern.
As described above, in the aerial image display system according to the embodiment of the present invention, in a case where the polarization separating element includes the active retardation layer or the active polarizer, the image display apparatus alternately displays the non-floating image R (the image for the non-floating image R) and the aerial image V1 (the image for the aerial image V1) by time-division.
In other words, in a case where the polarization separating element includes the active retardation layer or the active polarizer, in a case where the image display apparatus displays the non-floating image R, the polarization separating element switches the direction of the slow axis or the transmission axis (absorption axis) such that the optical path of the non-floating image R is obtained. In addition, in a case where the image display apparatus displays the aerial image V1, the polarization separating element switches the direction of the slow axis or the transmission axis such that the optical path of the aerial image V1 is obtained.
On the other hand, in a case where the polarization separating element is the patterned retardation layer or the patterned polarizer, the image display apparatus arranges and displays the non-floating image R (the image for the non-floating image R) and the aerial image V1 (the image for the aerial image V1) by dividing the images (space-division) depending on the pattern of the polarization separating element.
For example, in a case where the pattern of the polarization separating element is stripe-shaped and the regions where the slow axes or the transmission axes are orthogonal to each other are alternately arranged, the image display apparatus divides (space-division) the image for the non-floating image R and the image for the aerial image V1 in a stripe shape. In addition, the image display apparatus displays the divided non-floating image R corresponding to the region where the direction of the slow axis or the transmission axis of the polarization separating element 18 is the optical path of the non-floating image R, and displays the divided aerial image V1 corresponding to the region where the direction of the slow axis or the transmission axis of the polarization separating element 18 is the optical path of the aerial image V1.
Here, in
In addition, in the description of the examples shown in
Even in this configuration, likewise, in the aerial image display system, at the timing at which or in the region where the non-floating image R is displayed, the image display apparatus 16 displays only the non-floating image R by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the non-floating image R and cuts polarized light passing through the optical path for the aerial image V1, and at the timing at which or in the region where the aerial image V1 is displayed, the image display apparatus 16 displays only the aerial image V1 by operating such that the polarization separating element 18 allows transmission of only polarized light passing through the optical path for the aerial image V1 and cuts polarized light passing through the optical path for the non-floating image R. The aerial image display system can display the superimposed image V2 where the non-floating image R and the aerial image V1 are superimposed on each other by displaying the non-floating image R and the aerial image V1 by time-division or space-division.
In the liquid crystal display device, typically, two linear polarizers are provided in a crossed nicols state in a state where a liquid crystal cell is interposed between the linear polarizers. Accordingly, in the configuration where the polarization separating element 18 is disposed between the image display apparatus 16 and the half mirror 12 as in the example shown in
In consideration of this point, in the configuration where the active polarizer is used and the configuration where the patterned polarizer is used, it is advantageous to use a display device other than a liquid crystal display device as the image display apparatus, for example, to use an OLED as the image display apparatus.
In the aerial image display system according to the embodiment of the present invention, a position where the aerial image V1 is displayed, that is, a floating distance of the aerial image V1 can be adjusted by changing a separation distance between the image display apparatus and the half mirror, between the image display apparatus and the reflective polarizer, or between the half mirror and the reflective polarizer. Specifically, by increasing any one of the distances, the floating distance of the aerial image V1 can be increased.
In addition, in a configuration where the polarization separating element and the image display apparatus are spaced from each other with the half mirror interposed therebetween as in the example shown in
Accordingly, in the configuration where the image display apparatus and the polarization separating element are spaced from each other with the half mirror interposed therebetween, it is preferable to use the active retardation layer or the active polarizer as the polarization separating element 18.
[Input System]
By using the aerial image display system according to the embodiment of the present invention in combination with a noncontact touch sensor, an input system can be obtained.
Specifically, as shown in
In a case where the aerial image display system is used in this input system, the aerial image display system that displays only the aerial image V1 and does not display non-floating image R as shown in
As the noncontact touch sensor, a well-known noncontact touch sensor such as a noncontact infrared touch sensor that identifies an object by emitting infrared light and detecting the reflected infrared light, a noncontact capacitive touch sensor, a time-of-flight (TOF) sensor, a LIDAR sensor, or a noncontact touch sensor that images a finger or the like with one or a plurality of cameras to detect a touch position can be used.
In the example shown in
Hereinabove, the aerial image display system and the input system according to the embodiment of the present invention have been described above. However, the present invention is not limited to the above-described examples, and various improvements and modifications can be made within a range not departing from the scope of the present invention.
The present invention can be suitably used in a car navigation system, an input system, or the like.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-212093 | Dec 2020 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2021/045063 filed on Dec. 8, 2021, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2020-212093 filed on Dec. 22, 2020. The above applications are hereby expressly incorporated by reference, in its entirety, into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2021/045063 | Dec 2021 | US |
| Child | 18338561 | US |
