Patent Application
20200132887
The present invention relates to an optical element and a wearable display device.
Recently, a wearable display device such as a head-mounted display has been widely used. This wearable display device is a device that displays an image in the very vicinity of the eyes of a user using an extended optical system employing a virtual image. In addition, in the wearable display device, in order to display an image at a wide viewing angle in front of the eyes of the user, an eyepiece for enlarging an image displayed on a display panel is used.
In the wearable display device, in a case where the image displayed on the display panel is enlarged using the eyepiece, a pixel grid included in the display panel is also enlarged together with the image, and the pixel grid of the display panel is visually recognized by the user. As a result, the quality of the image may deteriorate. In JP2016-139112A, a microlens array sheet is disposed between a display panel and an eyepiece to diffuse light from the display panel such that a pixel grid is prevented from being visually recognized by the user.
JP2016-139112A discloses various countermeasures in order to prevent moire generated by interference between a two-dimensional spatial frequency of a pixel arrangement of a display panel and a two-dimensional spatial frequency of an arrangement pattern of microlenses in a microlens array sheet.
For example, a method of offsetting two-dimensional coordinates of a microlens center in the microlens array sheet from a pixel grid in the display panel is disclosed. However, it is difficult to prepare the microlens array sheet itself with this method, and this method is not industrially preferable.
It cannot be said that the countermeasures other than the above-described method are sufficient, and further improvement is required.
The present invention has been made in consideration of the above-described circumstances, and an object thereof is to provide an optical element that is suitably applicable to a wearable display device in which a pixel grid of a display panel is inconspicuous to a user and the generation of moire is suppressed.
In addition, another object of the present invention is to provide a wearable display device including the above-described optical element.
As a result of a thorough investigation on the above-described objects, the present inventors found that the desired effects can be obtained by using a predetermined optical element.
That is, it was found that the objects can be achieved by the following configurations.
(1) An optical element comprising:
a support; and
a plurality of dots that are arranged on the support and exhibit optical anisotropy,
in which the dots are formed of a composition including a liquid crystal compound, and
the optical element comprises the dots having a slow axis in a direction different from a direction in which the plurality of dots are arranged.
(2) The optical element according to claim 1, comprising:
two or more kinds of dots having different directions of slow axes.
(3) The optical element according to (1) or (2), further comprising:
an overcoat layer that is disposed on the support to cover the dots.
(4) The optical element according to (3),
in which an absolute value of a difference between a refractive index of the overcoat layer and an ordinary light refractive index of the liquid crystal compound is 0.2 or less.
(5) The optical element according to any one of (1) to (4),
in which the liquid crystal compound is a rod-shaped liquid crystal compound or a disk-shaped liquid crystal compound.
(6) The optical element according to any one of (1) to (5), which is used as a microlens array.
(7) A wearable display device comprising:
a display panel that includes a plurality of pixels and a pixel grid disposed between the plurality of pixels adjacent to each other;
an eyepiece for collecting light emitted from the display panel through the plurality of pixels; and
the optical element according to (6) that is disposed on an optical path of the display panel and the eyepiece.
According to the present invention, it is possible to provide an optical element that is suitably applicable to a wearable display device in which a pixel grid of a display panel is inconspicuous to a user and the generation of moire is suppressed.
In addition, according to the present invention, it is possible to provide a wearable display device including the above-described optical element.
Hereinafter, an embodiment of an optical element and a wearable display device according to the present invention will be described with reference to the drawings. In each of the drawings, for easy visual recognition, the reduced scale of components is different from the actual scale.
In this specification, numerical ranges represented by “to” include numerical values before and after “to” as lower limit values and upper limit values.
In this specification, for example, unless specified otherwise, an angle such as “45°”, “parallel”, or “perpendicular” represents that a difference from an exact angle is less than 5°. The difference from an exact angle is preferably less than 4° and more preferably less than 3°.
The optical element 10 includes: a support 12; and a plurality of dots 14A that are arranged on the support 12. As illustrated in
Each of the dots 14A exhibits optical anisotropy, and an arrow in
In
Hereinafter, members constituting the optical element 10 will be described in detail. Next, a method of manufacturing the optical element 10 will be described in detail.
(Support)
The support is a member for supporting the dots.
As the support, a transparent support is preferable, and examples thereof include a polyacrylic resin film such as polymethyl methacrylate, a cellulose resin film such as cellulose triacetate, and a cycloolefin polymer film (for example, trade name “ARTON”, manufactured by JSR Corporation; or trade name “ZEONOR”, manufactured by Zeon Corporation).
The support is not limited to a flexible film and may be a non-flexible substrate such as a glass substrate.
“Transparent” described in this specification represents that the non-polarized light transmittance (total transmittance) at a wavelength of 380 to 780 nm is preferably 50% or higher, more preferably 70% or higher, and still more preferably 85% or higher.
(Dot)
The dot exhibits optical anisotropy and has the slow axis. The dot exhibiting optical anisotropy represents that birefringence is exhibited in an in-plane direction of the dot. The in-plane direction represents a direction parallel to the support surface.
The dot is formed of a composition including a liquid crystal compound. As described below, it is preferable that the dot is formed by immobilizing the alignment of the liquid crystal compound. The composition to be used and a method of forming the dot will be described below.
As described below, in
The function of the optical element including the dots arranged as described above will be described using
Light components emitted through a plurality of pixels in a display panel included in a wearable display device described below are incident from the support side of the optical element. As illustrated in
On the other hand, light components L2 and L3 incident into positions deviating from the vicinity of the center of the dot 14A are bent on the surface of the dot 14A due to a difference in refractive index between the dot 14A and the air. That is, each of the light components L2 and L3 incident into the dot 14A is emitted in a direction inclined by a predetermined angle from the incident direction. In particular, the cross-section part obtained by cutting the dot in a direction parallel to the slow axis in the dot 14A illustrated in
On the other hand,
As illustrated in
In particular, the cross-section part obtained by cutting the dot 14A in a direction perpendicular to the slow axis in the dot 14A illustrated in
Therefore, in a case where the light incident from the support 12 side of the optical element 10 is emitted through the dot 14A, a method in which the light is bent in a direction parallel to the slow axis S and a method in which the light is bent in a direction perpendicular to the slow axis S are different from each other as illustrated in
As described above, the spreading of the light emitted from the dot 14A has anisotropy. By arranging the slow axes A of the dots 14A having the above-described characteristics in a direction different from the direction in which the dots 14A are arranged, interference generated in a case where the optical element and the display panel are laminated is suppressed, and thus moire is reduced.
An arrangement pattern of the dots is not particularly limited, and an optimum arrangement is appropriately selected depending on a pixel arrangement in the display panel. Examples of the arrangement pattern include a grid shape illustrated in
An arrangement density of the dots is not particularly limited and is appropriately selected depending on a pixel arrangement in the display panel.
Typically, in a case where the dots are seen from a normal direction of a main surface of the support, an area ratio of the dots to the support is preferably 5% to 100% and more preferably 10% to 95%.
The area ratio of the dots is obtained by obtaining an image using a microscope such as a laser microscope or a scanning electron microscope (SEM), measuring area ratios in a region having a size of 1 mm×1 mm, and obtaining an average value of area ratios at five positions.
It is preferable that the dot is circular in case of being seen from the normal direction of the main surface of the support.
The circular shape is not necessarily a perfect circle and may be a substantially circular shape. The center of the dot described herein refers to the center of the circle or the center of gravity. The dots are not particularly limited as long as the average shape of the dots is circular, and may include some dots having a shape other than a circular shape.
In addition, the dots may have a shape such as a hemispherical shape (substantially hemispherical shape), a spherical segment shape (substantially spherical segment shape), a spherical trapezoidal shape, a conical shape, or a truncated cone shape.
An inter-center distance (D in
The inter-center distance of the dots is preferably 1 to 150 μm and more preferably 5 to 100 μm.
The height of the dot is not particularly limited and is preferably 0.1 to 50 μm and more preferably 0.5 to 30 μm.
The height of the dot can be obtained from a cross-sectional view of the dot which is obtained by focal position scanning using a laser microscope or obtained using a microscope such as a SEM.
The diameter of the dot is not particularly limited and is preferably 1 to 150 μm and more preferably 5 to 100 μm.
As described above, the dot is formed of a composition including a liquid crystal compound.
Hereinafter, components included in the composition will be described in detail, and then a method of forming the dot will be described in detail.
Examples of the liquid crystal compound include a rod-shaped liquid crystal compound and a disk-shaped liquid crystal compound.
Examples of the rod-shaped liquid crystal compound include an azomethine compound, an azoxy compound, a cyanobiphenyl compound, a cyanophenyl ester compound, a benzoate compound, a phenyl cyclohexanecarboxylate compound, a cyanophenylcyclohexane compound, a cyano-substituted phenylpyrimidine compound, an alkoxy-substituted phenylpyrimidine compound, a phenyldioxane compound, a tolan compound, and an alkenylcyclohexylbenzonitrile compound. Not only the above-described low-molecular-weight liquid crystal compound but also a high-molecular-weight liquid crystal compound can be used.
Examples of the rod-shaped liquid crystal compound include compounds described in Makromol. Chem. (1989), Vol. 190, p. 2255, Advanced Materials (1993), Vol. 5, p. 107, U.S. Pat. Nos. 4,683,327A, 5,622,648A, 5,770,107A, WO95/022586A, WO95/024455A, WO97/000600A, WO98/023580A, WO98/052905A, JP1989-272551A (JP-H1-272551A), JP1994-016616A (JP-H6-016616A), JP1995-110469A (JP-H7-110469A), JP1999-080081A (JP-H11-080081A), and JP2001-064627A.
Examples of the disk-shaped liquid crystal compound include compounds described in JP2007-108732A and JP2010-244038A.
It is preferable that the liquid crystal compound has a polymerizable group. As the polymerizable group, an unsaturated polymerizable group, an epoxy group, or an aziridinyl group is preferable, an unsaturated polymerizable group is more preferable, and an ethylenically unsaturated polymerizable group is still more preferable.
The content of the liquid crystal compound in the composition is not particularly limited and is preferably 75 to 99.9 mass % and more preferably 80 to 99 mass % with respect to the total solid content in the composition.
As the liquid crystal compound, one kind may be used alone, or a combination of two or more kinds may be used.
The composition may include a component other than the liquid crystal compound.
For example, the composition may include a surfactant. Examples of the surfactant include a silicone surfactant and a fluorine surfactant.
The content of the surfactant in the composition is preferably 0.01 to 10 mass % and more preferably 0.01 to 5 mass % with respect to the total mass of the liquid crystal compound.
As the surfactant, one kind may be used alone, or two or more kinds may be used in combination.
The composition may include a polymerization initiator. As the polymerization initiator, a photopolymerization initiator is preferable, and a photopolymerization initiator that can initiate a polymerization reaction by ultraviolet irradiation is more preferable.
The content of the photopolymerization initiator in the composition is preferably 0.1 to 20 mass % and more preferably 0.5 to 12 mass % with respect to the content of the liquid crystal compound.
The composition may include a solvent. As the solvent, an organic solvent is preferable.
The content of the solvent in the composition is preferably 20 to 99 mass % with respect to the total mass of the composition.
In addition, the composition may optionally further include an alignment controller, a polymerizable compound, a polymerization inhibitor, an antioxidant, an ultraviolet absorber, a light stabilizer, a coloring material, and metal oxide particles.
The method of forming the dot is not particularly limited, and examples thereof include: a method of applying a composition including a polymerizable liquid crystal compound to the support in a dot shape and curing the composition; a method of uniformly applying a composition including a polymerizable liquid crystal compound to the support, pressing the composition with a mold having a state where the dot portion is recessed, and curing the composition; and a method of applying a composition including a polymerizable liquid crystal compound to a mold having a state where the dot portion is recessed and curing the composition.
Hereinafter, the procedure of the method of applying a composition including a polymerizable liquid crystal compound to the support in a dot shape and curing the composition will be described in detail.
First, as the method of applying the composition to the support, an ink jet method (jetting of the composition) or a printing method is preferable. The kind of the printing method is not particularly limited, and examples thereof include a gravure printing method, a flexographic printing method, and a screen printing method. In particular, an ink jet method is preferable from the viewpoint of easily adjusting the jetting amount of ink droplets and/or jetting positions of ink droplets.
The composition applied to the support is optionally dried or heated and then is cured to form the dot.
In the drying and/or heating step, the liquid crystal compound in the composition only has to be aligned. In the case of heating, the heating temperature is preferably 200° C. or lower and more preferably 130° C. or lower.
It is preferable that the aligned liquid crystal compound is further polymerized and immobilized. Regarding the polymerization, thermal polymerization or photopolymerization using light irradiation may be performed, and photopolymerization is preferable. Regarding the light irradiation, ultraviolet light is preferably used. The irradiation energy is preferably 100 to 1,500 mJ/cm2. In order to promote a photopolymerization reaction, light irradiation may be performed under heating conditions or in a nitrogen atmosphere.
(Other Members)
The optical element may include other members other than the support and the dots.
For example, the optical element may further include an alignment film between the support and the dots. The alignment film is a film having an alignment restriction force of adjusting the direction of the slow axes of the dots formed thereon.
Examples of the alignment film include a rubbed film formed of an organic compound such as a polymer, an obliquely deposited film formed of an inorganic compound, a film having a microgroove, and a film formed by lamination of Langmuir-Blodgett (LB) films formed with a Langmuir-Blodgett's method using an organic compound. The rubbing treatment is performed by rubbing a surface of a polymer layer with paper or fabric in a given direction multiple times.
In addition, examples of the alignment film include a so-called photo-alignment film obtained by irradiating a photo-alignable material with polarized light or non-polarized light.
Further, an optically-anisotropic layer itself that is formed of the composition including the liquid crystal compound may be used as the alignment film.
The alignment film may have a single-layer structure or a multi-layer structure. In the case of the multi-layer structure, for example, an aspect including a photo-alignment film and another alignment film (for example, an optically-anisotropic layer) disposed on the photo-alignment film may be adopted.
In addition, the optical element may further include an overcoat layer that is disposed on the support to cover the dots. By disposing the overcoat layer, the spreading of outgoing light in the slow axis direction of the dots and the spreading of outgoing light in the direction in which the dots are arranged can be more accurately controlled. In addition, the shape of the dots from the outside can be protected.
In addition, an absolute value of a difference between a refractive index of the overcoat layer and an ordinary light refractive index of the liquid crystal compound is not particularly limited and, from the viewpoint of further suppressing the generation of moire, is preferably 0.2 or less and more preferably 0.1 or less. The lower limit is not particularly limited and, for example, 0.
The refractive index of the overcoat layer and the ordinary light refractive index of the liquid crystal compound are refractive indices at a wavelength of 589 nm.
The thickness of the overcoat layer is not particularly limited and is preferably 0.1 to 50 μm and more preferably 0.5 to 30 μm.
A method of forming the overcoat layer is not particularly limited, and examples thereof include a method including: applying an overcoat layer-forming composition including a polymerizable compound to the support on which the dots are arranged and curing the composition.
An optical element 100 includes: the support 12; and a plurality of dots 14A and a plurality of dots 14B that are arranged on the support 12.
The optical element 100 has the same configuration as that of the optical element 10 according to the first embodiment, except that two kinds of dots having different directions of slow axes are provided. Therefore, the same components as those of the first embodiment will be represented by the same reference numerals, and the description thereof will not be repeated.
In addition, the configurations of the dots 14A and the dots 14B are the same except that the directions of the slow axes are different.
That is, the optical element 100 and the optical element 10 are only different in that the directions in which the slow axes in the dots are arranged are different.
In the optical element 100, the slow axes in the dots 14A and the slow axes in the dots 14B are perpendicular to each other.
In addition, in
Further, in
By providing the two kinds of dots having different directions of slow axes, the generation of moire is further suppressed as compared to the first embodiment.
In the first embodiment, only the dots in which the directions of the slow axes are aligned with one direction are provided. In the second embodiment, only the dots in which the directions of the slow axes are aligned with two directions are provided. However, the present invention is not limited to these embodiments. That is, an optical element including three or more kinds of dots having different directions of slow axes or an optical element 110 according to a third embodiment including dots 14C having random directions of slow axes as illustrated in
In addition, the optical element according to the embodiment of the present invention includes dots (hereinafter, also referred to as “dots X”) having a slow axis of which a direction is different from the direction in which the plurality of dots are arranged. In particular, the number of the dots X is preferably 50% or higher, more preferably 70% or higher, and still more preferably 100% with respect to all the dots.
An optical element 120 includes: the support 12; and a plurality of dots 14A that are arranged on the support 12. As illustrated in
The optical element 120 has the same configuration as that of the optical element 10 according to the first embodiment, except that the directions in which the dots are arranged are different. Therefore, the same components as those of the first embodiment will be represented by the same reference numerals, and the description thereof will not be repeated.
<Use>
The optical element is suitably applicable to various uses, and examples of the uses include a diffuser for a head-up display of an automobile ad a microlens array for a three-dimensional display.
In particular, the optical element according to the embodiment of the present invention is suitably applicable to a microlens array included in a wearable display device.
Hereinafter, the wearable display device including the optical element will be described in detail.
<Wearable Display Device>
A wearable display device 20 includes: a display panel 22 for displaying an image; an eyepiece 24 for collecting light emitted from the display panel 22; and the optical element 10 that is disposed between the display panel 22 and the eyepiece 24 (on an optical path thereof). In a case where a user uses the wearable display device 20, the eyepiece 24 is disposed in the very vicinity of an eye 26 of the user. Therefore, an image that is displayed on the display panel 22 and is enlarged by the eyepiece 24 is visually recognized by the user.
The size and arrangement pattern of the dots in the optical element 10 can be appropriately adjusted depending on the size and arrangement pattern of the pixels in the display panel.
In a case where the optical element 10 and the display panel 22 are laminated, it is preferable that the arrangement direction of the dots 14A in the optical element 10 and the pixel arrangement direction in the display panel 22 match each other.
In addition, as illustrated in
As described above, in the optical element 10, the pixel grid of the display panel is inconspicuous to the user as in the microlens array. Further, by adjusting the slow axes of the dots 14A in the optical element 10, the generation of moire is suppressed even in a case where the arrangement direction of the dots in the optical element matches the pixel arrangement direction in the display panel.
Hereinafter, the present invention will be described in detail using examples. Materials, reagents, proportions thereof, operations, and the like shown in the following Examples can be appropriately changed as long as they do not depart from the scope of the present invention. Accordingly, the scope of the present invention is not limited to the following specific examples.
(Saponification of Support)
As the support, a commercially available triacetyl cellulose “Z-TAC” (manufactured by Fuji Film Co., Ltd.) was used. The support was caused to pass through an induction heating roll at a temperature of 60° C. such that the support surface temperature was increased to 40° C. Next, an alkali solution shown below was applied to a single surface of the support using a bar coater in an application amount of 14 mL/m2, the support was heated to 110° C., and the support was transported for 10 seconds under a steam infrared electric heater (manufactured by Noritake Co., Ltd.). Next, 3 mL/m2 of pure water was applied to the support surface using the same bar coater. Next, water cleaning using a foundry coater and water draining using an air knife were repeated on the obtained support three times, and then the support was transported and dried in a drying zone at 70° C. for 10 seconds. As a result, the support having undergone the alkali saponification treatment was obtained.
(Alkali Solution)
(Formation of Undercoat Layer)
The following undercoat layer-forming coating solution was continuously applied to the support having undergone the alkali saponification treatment using a #8 wire bar. The support on which the coating film was formed was dried using warm air at 60° C. for 60 seconds and was dried using warm air at 100° C. for 120 seconds. As a result, an undercoat layer was formed.
(Formation of Photo-Alignment Film)
The following photo-alignment film-forming coating solution was continuously applied to the support on which the undercoat layer was formed using a #2 wire bar. The obtained support was dried using warm air at 60° C. for 60 seconds to form a coating film.
The coating film formed as described above was exposed to ultraviolet light at an exposure dose of 100 mJ/cm2 through a wire grid polarizing plate of which a transmission axis is inclined by 45° from a longitudinal direction of the film. As a result, a photo-alignment film was formed.
(Formation of Alignment Film)
In a container held at 25° C., the following components were mixed with each other to prepare an alignment film-forming coating solution.
Numerical values are represented by mass %. In addition, R represents a group to be bonded to oxygen.
The alignment film-forming coating solution was applied to the photo-alignment film using a #2.6 bar coater. Next, the coating film was heated such that the film surface temperature was 95° C., and then was dried for 60 seconds. Next, in a nitrogen purged atmosphere having an oxygen concentration of 100 ppm or lower, the coating film was irradiated with ultraviolet light at 500 mJ/cm2 using an ultraviolet irradiation device to promote a crosslinking reaction. As a result, an alignment film was formed.
(Formation of Dot)
In a container held at 25° C., the following components were mixed with each other to prepare a liquid crystal ink solution LI-1.
Using an ink jet printer (DMP-2831, manufactured by Fujifilm Dimatix Inc.), the liquid crystal ink solution LI-1 was jetted to the alignment film to form a grid-shaped pattern (refer to
As illustrated in
The coating film of the photo-alignment film-forming coating solution prepared using the same method as that of Example 1 was irradiated with ultraviolet light at an exposure dose of 100 mJ/cm2 through a wire grid polarizing plate of which a transmission axis was inclined by 45 degrees from a longitudinal direction of the film and a strip-shaped photomask having L/S=30 μm/30 μm.
Next, after shifting the photomask by 30 μm, a portion that was not exposed in the above process was irradiated with ultraviolet light at an exposure dose of 100 mJ/cm2 through a wire grid polarizing plate of which a transmission axis was inclined by 135 degrees from a longitudinal direction of the film and a strip-shaped photomask having L/S=30 μm/30 μm.
An optical element 2 was prepared using the same method as that of Example 1 except for the above-described configuration.
As illustrated in
An overcoat layer-forming composition having the following composition was applied to the optical element 2 to cover the dots of the optical element 2 formed in Example 2 and was dried at 50° C. for 1 minute. Next, using an ultraviolet irradiation device, the coating film was irradiated with ultraviolet light at 500 mJ/cm2 at room temperature and was cured. As a result, an optical element 3 including the overcoat layer was prepared.
In addition, a refractive index of the overcoat layer was 1.48, an ordinary light refractive index of the rod-shaped liquid crystal compound was 1.51, and an absolute value of a difference between the refractive index of the overcoat layer and the ordinary light refractive index of the rod-shaped liquid crystal compound was 0.03.
The ordinary light refractive index of the rod-shaped liquid crystal compound was measured using an Abbe refractometer by separately preparing an optical film for measuring a refractive index using the liquid crystal ink solution LI-1. Specifically, the optical film for measuring a refractive index was prepared as follows. An undercoat layer was formed on high refractive index glass using the same method as described above, a rubbing treatment was performed, and the liquid crystal ink solution LI-1 was applied such that the thickness after drying was 10 μm. Next, the high refractive index glass on which the coating film was disposed was dried at 95° C. for 180 seconds. Next, in a nitrogen purged atmosphere having an oxygen concentration of 100 ppm or lower, the coating film was irradiated with ultraviolet light at 500 mJ/cm2 using an ultraviolet irradiation device to promote a crosslinking reaction. As a result, the optical film for measuring a refractive index was formed.
An optical element 4 was prepared using the same method as that of Example 1, except that the following liquid crystal ink solution LI-2 was used instead of the liquid crystal ink solution LI-1.
Liquid Crystal Compound L-2-
Liquid Crystal Compound L-3-
Polymerization initiator PI-1-
Leveling Agent T-1-
An optical element 5 was prepared using the same method as that of Example 1, except that the following liquid crystal ink solution LI-3 was used instead of the liquid crystal ink solution LI-1.
Discotic Liquid Crystal 2
Vertical Alignment Agent (S01)
Vertical Alignment Agent (S02)
Fluorine-Containing Compound A
Fluorine-Containing Compound B
An optical element 6 was prepared using the same method as that of Example 2, except that the following liquid crystal ink solution LI-3 was used instead of the liquid crystal ink solution LI-1.
Playstation VR (manufactured by Sony Interactive Entertainment Inc.) was disassembled, and a sheet (microlens array) bonded to a display portion was removed. In this state, Playstation VR was assembled again. An image was displayed and was observed through a lens to perform <Evaluation> described below.
Playstation VR (manufactured by Sony Interactive Entertainment Inc.) was disassembled, and an image was displayed without removing a sheet (microlens array) bonded to a display portion and was observed through a lens to perform <Evaluation> described below.
<Evaluation>
Playstation VR (manufactured by Sony Interactive Entertainment Inc.) was disassembled, and a sheet (microlens array) bonded to a display portion was removed. Next, each of the optical elements 1 to 6 according to Examples was bonded to the display portion. At this time, surfaces on the support side were bonded through a pressure sensitive adhesive. After assembling Playstation VR again, an image was displayed and was observed through a lens to perform <Evaluation> described below.
(Pixel Grid Visibility)
By using a white solid image as the image to be displayed on the image display portion, the pixel grid was observed by visual inspection, and evaluation was performed based on the following four grades.
A: the pixel grid was not visually recognized
B: the pixel grid was visually recognized, but the degree thereof was small
C: the pixel grid was visually recognized, but the degree thereof was in an allowable range
D: the pixel grid was clearly visually recognized
(Moire)
By using a white solid image as the image to be displayed on the image display portion, moire was observed by visual inspection, and evaluation was performed based on the following four grades.
A: the moire was not visually recognized
B: the moire was visually recognized, but the degree thereof was small
C: the moire was visually recognized, but the degree thereof was in an allowable range
D: the moire was conspicuous
In the item “Liquid Crystal Compound” of Table 1, “R1” and “R2” represent rod-shaped liquid crystal compounds, respectively, and “D” represents a disk-shaped liquid crystal compound.
In addition, in the item “Alignment Pattern of Slow Axes of Dots”, “
In addition, the item “Whether or Not OC Layer is Provided” represents whether or not the overcoat layer was provided, “Not Provided” represents that the overcoat layer was not provided, and “Provided” represents that the overcoat layer was provided.
As shown in Table 1, by using the optical element according to the embodiment of the present invention, the desired effects were obtained.
In particular, it was found from Examples 2 and 6 that, in a case where two or more kinds of dots having different directions of slow axes are provided, the effects are higher.
In addition, it was found from a comparison between Examples 2 and 3 that, by providing the overcoat layer, the effects are higher.
Next, samples according to Examples 7 and 8 were prepared using the same methods as those of Examples 2 and 3, except that the ink solution was jetted to form a hexagonal close-packed pattern (refer to
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-129187 | Jun 2017 | JP | national |
This application is a Continuation of PCT International Application No. PCT/JP2018/024925 filed on Jun. 29, 2018, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2017-129187 filed on Jun. 30, 2017. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2018/024925 | Jun 2018 | US |
| Child | 16728855 | US |
