The present application claims priority to Japanese Priority Patent Application JP 2012-255659 filed in the Japan Patent Office on Nov. 21, 2012, the entire content of which is hereby incorporated by reference.
The present disclosure relates to a light source device, a display unit, and an electronic apparatus that enable stereoscopic viewing and multiple viewing in a parallax barrier system.
A stereoscopic display unit of parallax barrier system is known as one of stereoscopic display systems capable of providing stereoscopic viewing with naked eyes without special glasses. The stereoscopic display unit has a parallax barrier that is disposed so as to face a front surface (display surface side) of a two-dimensional display panel. A typical configuration of the parallax barrier includes shielding sections and stripe-shaped openings (slits) that are alternately arranged in a horizontal direction. The shielding section shields display image light from the two-dimensional display panel, and the stripe-shaped opening allows the display image light to pass therethrough.
In the parallax barrier system, parallax images for stereoscopic viewing (a perspective image for right eye and a perspective image for left eye in the case of two perspectives) are displayed, in a space-divisional manner, on the two-dimensional display panel, and the parallax images are separated in the horizontal direction by the parallax barrier, thereby achieving stereoscopic viewing. It is possible to allow light of different perspective images to separately enter right and left eyes of a viewer through the slits by appropriately setting a width of each of the slits of the parallax barrier and the like when the viewer views the stereoscopic display unit from a predetermined position in a predetermined direction.
Note that, in the case where a transmissive liquid crystal display panel is used as the two-dimensional display panel, for example, it is possible to dispose a parallax barrier on a back surface side of the two-dimensional display panel. In this case, the parallax barrier is disposed between the transmissive liquid crystal display panel and a backlight. In Japanese Unexamined Patent Application Publication No. 2012-226294, there is disclosed a light source device in which a scattering pattern is provided on an internal reflection surface of a light guide plate serving as a backlight and thus the light guide plate has a function equivalent to a parallax barrier.
As described in Japanese Unexamined Patent Application Publication No. 2012-226294, in the case of the configuration in which the light guide plate has a function equivalent to a parallax barrier, in-plane luminance distribution of light emitted from the light guide plate may be preferably uniform. In Japanese Unexamined Patent Application Publication No. 2012-226294, the shape of the scattering pattern is modified depending on positions, and thus in-plane luminance distribution is allowed to be uniform. On the other hand, even in the case where a scattering pattern having a uniform shape is provided, uniform in-plane luminance distribution is desired.
Accordingly, it is desirable to provide a light source device, a display unit, and an electronic apparatus that achieve a function equivalent to a parallax barrier with use of a light guide plate, and improve non-uniformity of in-plane luminance distribution.
According to an embodiment of the technology, there is provided a light source device including: one or a plurality of first light sources each configured to emit first illumination light; and a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit light for displaying a plurality of perspective images to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface. The one or the plurality of first light sources are arranged to face at least the first end surface, and an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
According to an embodiment of the technology, there is provided a display unit including a display section configured to display a plurality of perspective images, and a light source device configured to emit light for displaying the plurality of perspective images toward the display section. The light source device includes: one or a plurality of first light sources each configured to emit first illumination light; and a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit the light to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface. The one or the plurality of first light sources are arranged to face at least the first end surface, and an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
According to an embodiment of the technology, there is provided an electronic apparatus provided with a display unit, the display unit including a display section configured to display a plurality of perspective images and a light source device configured to emit light for displaying the plurality of perspective images toward the display section. The light source device includes: one or a plurality of first light sources each configured to emit first illumination light; and a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit the light to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface. The one or the plurality of first light sources are arranged to face at least the first end surface, and an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
In the light source device, the display unit, and the electronic apparatus according to the respective embodiments of the present disclosure, the first illumination light from the first light source is scattered by the scattering regions and is emitted to the outside of the light guide plate. Therefore, it is possible to allow the light guide plate to have a function as a parallax barrier with respect to the first illumination light. In other words, equivalently, the light guide plate functions as a parallax barrier with the scattering regions as openings (slits). Therefore, it is possible to achieve three-dimensional display and multiple viewing.
Moreover, non-uniformity in luminance distribution of light emitted from the light guide plate (in-plane luminance distribution of the first illumination light) is improved by the inclined section provided between the first light source and the predetermined region of the light guide plate.
In the light source device, the display unit, and the electronic apparatus according to the respective embodiments of the present disclosure, the plurality of scattering regions scattering the first illumination light are provided on the light guide plate. Therefore, it is possible to allow the light guide plate to have a function as a parallax barrier equivalently, with respect to the first illumination light.
In addition, the inclined section guiding the first illumination light to the predetermined region is provided between the first light source and the predetermined region of the light guide plate. Therefore, it is possible to improve non-uniformity in in-plane luminance distribution of the first illumination light.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the technology as claimed.
Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the specification, serve to explain the principles of the technology.
Hereinafter, some embodiments of the disclosure will be described in detail with reference to drawings. Note that description will be given in the following order.
1. First Embodiment
2. Second Embodiment
3. Third Embodiment
4. Fourth Embodiment
5. Other Embodiments
Incidentally, in the first embodiment, a first direction (a vertical direction) in a display surface (an arrangement surface of pixels) of the display section 1 or in a plane parallel to the second internal reflection surface 3B of the light guide plate 3 is referred to as the Y direction (
The display unit is capable of selectively switching over a display mode arbitrarily between a two-dimensional (2D) display mode over the entire screen and a three-dimensional (3D) display mode over the entire screen. The switching over between the two-dimensional display mode and the three-dimensional display mode is allowed to be performed through switching control of image data to be displayed on the display section 1 and ON-OFF switching control of the first light source 2 and the second light source 7.
The display section 1 is configured using a transmissive two-dimensional display panel such as a transmissive liquid crystal display panel. For example, as illustrated in
For example, the first light source 2 may be configured using a fluorescent lamp such as a cold cathode fluorescent lamp (CCFL), or light emitting diode (LED). The first light source 2 emits first illumination light L1 (
The second light source 7 is disposed so as to face a side provided with the second internal reflection surface 3B of the light guide plate 3. The second light source 7 emits second illumination light L10 from a direction different from that of the first light source 2 toward the light guide plate 3. More specifically, the second light source 7 emits the second illumination light L10 from the outside (the back surface side of the light guide plate 3) toward the second internal reflection surface 3B (see
The light guide plate 3 may be configured of a transparent plastic plate made of, for example, an acrylic resin. All of surfaces of the light guide plate 3 are transparent except for the second internal reflection surface 3B. In other words, the first internal reflection surface 3A and four end surfaces are transparent over the respective entire surfaces.
The first internal reflection surface 3A is subjected to mirror processing over the entire surface, and internally totally reflects the light beams entering the light guide plate 3 at an incident angle satisfying a total-reflection condition in the light guide plate 3, and emits part of the light beams that do not satisfy the total-reflection condition to the outside.
The second internal reflection surface 3B has scattering regions 31 and total reflection regions 32. For example, the scattering region 31 is configured of a scattering material printed on a surface of the light guide plate 3, or is subjected to laser processing, sandblast processing, or the like, thereby being added with light scattering property. In the second internal reflection surface 3B, in the case of the three-dimensional display mode, the scattering region 31 functions as an opening (a slit) as a parallax barrier with respect to the first illumination light L1 from the first light source 2, and the total reflection region 32 functions as a shielding section. In the second internal reflection surface 3B, the scattering regions 31 and the total reflection regions 32 are provided in a pattern corresponding to a parallax barrier. Specifically, the total reflection regions 32 are provided in a pattern corresponding to the shielding sections of the parallax barrier, and the scattering regions 31 are provided in a pattern corresponding to the openings of the parallax barrier. Note that the barrier pattern of the parallax barrier is not particularly limited, and various types of patterns such as a stripe pattern in which a large number of vertically-long slit-like openings are arranged side by side in the horizontal direction with the shielding sections in between may be used.
The first internal reflection surface 3A and the total reflection regions 32 of the second internal reflection surface 3B internally totally reflects a light beam that has entered the light guide plate 3 at the incident angle satisfying the total-reflection condition (internally totally reflects a light beam that has entered at an incident angle larger than a predetermined critical angle). Therefore, the first illumination light L1 from the first light source 2 that has entered the light guide plate 3 at an incident angle satisfying the total-reflection condition is guided to a side surface direction by internal total reflection between the first internal reflection surface 3A and the total reflection regions 32 of the second internal reflection surface 3B. As illustrated in
As illustrated in
An inclined section 4 (
(Basic Operation of Display Unit)
When the display unit performs display in the three-dimensional display mode, the display section 1 performs image display based on the three-dimensional image data, and the first light source 2 and the second light source 7 are ON (lighting)-OFF (non-lighting) controlled for three-dimensional display. Specifically, as illustrated in
On the other hand, when the display unit performs display in the two-dimensional display mode, the display section 1 performs image display based on the two-dimensional image data, and the first light source 2 and the second light source 7 are ON (lighting)-OFF (non-lighting) controlled for two-dimensional display. Specifically, as illustrated in
Note that, even if only the second light source 7 is turned on, the second illumination light L10 is emitted from almost the entire surface of the light guide plate 3. However, the first light source 2 may be turned on as necessary. As a result, for example, in the case where lighting of only the second light source 7 is not enough to eliminate difference in luminance distribution between a part corresponding to the scattering regions 31 and a part corresponding to the total reflection regions 32, appropriate adjustment of the lighting state of the first light source 2 (ON-OFF control or adjustment of an amount of the lighting) allows optimization of the luminance distribution over the entire surface. However, in the case of performing two-dimensional display, for example, when the display section 1 can perform sufficient luminance correction, it is only necessary to turn on the second light source 7.
(Detailed Description of Structure of End Sections of Light Guide Plate)
The inclined section 4 and the reflector 5 provided in the end sections of the light guide plate 3 are provided to vary angular distribution of the first illumination light L1 propagating through the inside of the light guide plate 3 and to improve non-uniformity of an amount of light beams entering the scattering regions 31. For example, in the case where the inclined section 4 and the reflector 5 are not provided in the end sections of the light guide plate 3 as with a display unit according to a comparative example illustrated in
To improve the non-uniformity in luminance distribution as illustrated in
When a thickness T of the light guide plate 3 and the thickness t of the incident end are determined, an inclined angle θ and an inclined length L of the inclined section 4 have a relationship represented by the following expression. The inclined angle θ is an inclined angle with respect to the first internal reflection surface 3A or the second internal reflection surface 3B of the light guide plate 3.
θ=arctan [(T−t)/2L]
When the inclined angle θ and the inclined length L are both large, effect of making the light that is collectively emitted from the first end section close to the first light source 2, partially reach the second end section on an opposed side is large. However, since the thickness T of the light guide plate 3 is determined from a design condition of stereoscopic viewing with naked eyes, and the thickness t of the incident end is substantially determined from the size of the first light source 2, the inclined angle θ and the inclined length L of the inclined section 4 are defined by above-described expression. In the case where the thickness T of the light guide plate 3 and the thickness t of the incident end are determined by the above-described expression, when the inclined length L of the inclined section 4 is increased, effect of concentrating the luminance distribution on the second end section side is more increased, and effect of uniformizing the luminance distribution is also increased. However, since the inclined angle θ is decreased along with the inclined length L being increased, the effect of uniformization is stopped at a certain level. Therefore, it is desirable to determine the shape of the inclined section 4 within a range smaller than a value of the inclined length L that is most effective in uniformization.
Next, the structure of the second end surface 52 and the reflector 5 for improving the non-uniformity in luminance distribution of light emitted from the light guide plate 3 is described with reference to
β=γ−α
arcsin(n0/n1)≦β
The second end surface 52 and the reflector 5 are inclined in order to make the homeward smallest propagation angle β be decreased and to allow the light that has propagated through the inside of the light guide plate 3 to propagate through the light guide plate 3 again and then enter the scattering regions 31. When the homeward smallest propagation angle β is smaller than a critical angle of the light guide plate 3, the light is unintentionally emitted from the light guide plate 3, which results in luminance unevenness and degradation in light usage efficiency. Therefore, the luminance distribution is allowed to be adjusted by varying the inclined angle α within the range satisfying the above-described expressions.
(Specific Example of Improved Luminance Distribution on Light Emission Surface)
Hereinafter, a specific example of improved luminance distribution in the case where the inclined section 4 and the reflector 5 are not provided on the end sections of the light guide plate 3 (
Next, Table 1 illustrates more specific numerical examples of the configuration of the end sections of the light guide plate 3. As the specific numerical examples, a screen size of the display section 1 and a number of perspectives of the three-dimensional display were specifically set, and desirable configuration parameters of the inclined section 4 and the reflector 5 were set. The non-uniformity of the luminance distribution was favorably improved when the configuration parameters were set to the numerical examples of Table 1.
According to the above-described numerical examples, the inclined angle θ of the inclined section 4 may be desirably equal to or larger than 5 degrees and equal to or smaller than 20 degrees. More desirably, the inclined angle θ may be equal to or larger than 8 degrees and equal to or smaller than 11 degrees. In addition, the inclined angle α of the reflector 5 may be desirably equal to or larger than 0 degrees and equal to or smaller than 15 degrees. More desirably, the inclined angle α may be equal to or larger than 6 degrees and equal to or smaller than 11 degrees.
(Modifications)
Next, a display unit according to a second embodiment is described. Note that like numerals are used to designate substantially like components of the display unit according to the first embodiment, and the description thereof is appropriately omitted.
Next, a display unit according to a third embodiment of the present disclosure is described. Note that like numerals are used to designate substantially like components of the display unit according to the first or second embodiment, and the description thereof is appropriately omitted.
Although the configuration example in which the first light sources 2 are arranged in the vertical direction (the Y direction) of the light guide plate 3 is described in the first and second embodiments, the first light source 2 may be arranged in a lateral direction (the X direction).
Incidentally, the first light source 2 may be provided on both the third end surface 53 and the fourth end surface 54. In this case, as with the configuration example of
Next, a display unit according to a fourth embodiment of the present disclosure is described. Note that like numerals are used to designate substantially like components of the display unit according to any of the first to third embodiments, and the description thereof is appropriately omitted.
The light guide plate 3 for three-dimensional display emits light toward the display section 1 side with use of, for example, a scattering reflection pattern, and thus the light is spread in a state close to Lambertian scattering. On the other hand, the second light source 7 that is a backlight for two-dimensional display collects light in a front direction with use of, for example, a prism sheet. Therefore, the light emitted from the second light source 7 is distributed in a narrow range as compared with the light emitted from the light guide plate 3. If the light distribution by the light guide plate 3 for three-dimensional display differs from the light distribution by the second light source 7 for two-dimensional display as described above, when both the light guide plate 3 (the first light source 2) and the second light source 7 emit light in two-dimensional display, or when display is switched between two-dimensional display and three-dimensional display, difference in light distribution is perceived, which results in inconvenience for a user.
Thus, the light distribution by the second light source 7 is allowed to be approached to the same or substantially the same as the light distribution of the light guide plate 3 for three-dimensional display so that the above-described disadvantage is dissolved. When the light distribution by the second light source 7 that is the backlight for two-dimensional display is expanded, the light distribution by the second light source 7 approaches the light distribution by the light guide plate 3 for three-dimensional display. Therefore, specifically, an optical member having effect of expanding light distribution, such as a diffuser plate, a diffuser sheet, and a prism sheet is disposed as the diffusion optical member 6 between the light guide plate 3 and the second light source 7 as illustrated in
The technology in the present disclosure is not limited to the above-described embodiments, and various modifications may be made.
For example, the display unit according to any of the above-described embodiments is applicable to various electronic apparatuses having a display function.
In addition, in the above-described embodiments, the configuration example of the light guide plate 3 in which the scattering regions 31 and the total reflection regions 32 are provided on the second internal reflection surface 3B side has been described. However, the scattering regions 31 and the total reflection regions 32 may be provided on the first internal reflection surface 3A side.
Moreover, in the above-described embodiments, the case where the first illumination light L1 from the first light source 2 is used for three-dimensional display has been exemplified. However, instead of the three-dimensional display, so-called multi-view display allowing different images to be viewed depending on viewing directions may be performed.
Furthermore, for example, the technology may be configured as follows.
(1) A display unit including a display section configured to display a plurality of perspective images, and a light source device configured to emit light for displaying the plurality of perspective images toward the display section, the light source device including:
one or a plurality of first light sources each configured to emit first illumination light; and
a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit the light to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface, wherein
the one or the plurality of first light sources are arranged to face at least the first end surface, and
an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
(2) The display unit according to (1), wherein
the light guide plate has a first internal reflection surface and a second internal reflection surface, and
an inclined angle of the inclined section with respect to the first internal reflection surface or the second internal reflection surface is about 5 degrees or more and about 20 degrees or less.
(3) The display unit according to (1) or (2), wherein the second end surface is provided with a reflector guiding the first illumination light that has reached the second end surface, to the predetermined region.
(4) The display unit according to (3), wherein
the light guide plate has a first internal reflection surface and a second internal reflection surface, and
the second end surface and the reflector are each inclined at an angle of about 0 degrees or more and about 15 degrees or less with respect to a normal to the first internal reflection surface or the second internal reflection surface.
(5) The display unit according to any one of (1) to (4), wherein the inclined section is provided between the first end surface and the predetermined region of the light guide plate.
(6) The display unit according to any one of (1) to (4), wherein the inclined section is provided between the first end surface and the first light source separately from the light guide plate.
(7) The display unit according to (1) or (2), wherein
two first light sources are provided, one of the two first light sources being arranged to face the first end surface, and the other being arranged to face the second end surface, and
the inclined section is provided between the predetermined region and the first light source that is arranged to face the first end surface, and between the predetermined region and the first light source that is arranged to face the second end surface.
(8) The display unit according to any one of (1) to (7), further including a second light source provided to face the light guide plate, the second light source being configured to emit second illumination light toward the light guide plate from a direction different from an emitting direction of the first light source.
(9) The display unit according to (8), wherein
the display section selectively switches display between the plurality of perspective images based on three-dimensional image data and an image based on two-dimensional image data, and
the second light source is controlled to be in a non-lighting state when the plurality of perspective images are displayed on the display section, and is controlled to be in a lighting state when the image based on the two-dimensional image data is displayed on the display section.
(10) The display unit according to (9), wherein the first light source is controlled to be in a lighting state when the plurality of perspective images are displayed on the display section, and is controlled to be in the non-lighting state or the lighting state when the image based on the two-dimensional image data is displayed on the display section.
(11) A light source device including:
one or a plurality of first light sources each configured to emit first illumination light; and
a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit light for displaying a plurality of perspective images to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface, wherein
the one or the plurality of first light sources are arranged to face at least the first end surface, and
an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
(12) An electronic apparatus provided with a display unit, the display unit including a display section configured to display a plurality of perspective images and a light source device configured to emit light for displaying the plurality of perspective images toward the display section, the light source device including:
one or a plurality of first light sources each configured to emit first illumination light; and
a light guide plate having a first end surface, a second end surface, and a plurality of scattering regions, and scattering the first illumination light in the plurality of scattering regions to emit the light to outside, the first end surface and the second end surface being opposed to each other, and the plurality of scattering regions being provided with a constant density and a uniform shape in a predetermined region between the first end surface and the second end surface, wherein
the one or the plurality of first light sources are arranged to face at least the first end surface, and
an inclined section guiding the first illumination light to the predetermined region is provided between the one or the plurality of first light sources and the predetermined region of the light guide plate.
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
Number | Date | Country | Kind |
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2012-255659 | Nov 2012 | JP | national |