JP2012234093A - Stereoscopic image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission type display device that can display satisfactory 3-dimensional images observable by an observer with naked eyes and also satisfactory 2-dimensional images even when displaying 2-dimensional images, and that is reduced in thickness and in weight.SOLUTION: A display device 10 comprises: an LCD panel 13; a light source part 11; and a lense sheet 12 which is disposed between the LCD panel 13 and the light source part 11, and on which a plurality of linear Fresnel lenses 121 are arranged. When the display device 10 displays a 3-dimensional image, the LCD panel 13 displays four parallax images while switching them at a predetermined cycle. The light source part 11 includes four point light sources 112 in the arrangement direction of the linear Fresnel lenses 121 in regions corresponding to the respective linear Fresnel lenses 121, and turns on the point light sources 112 corresponding to the respective parallax images in synchronization with switching of the parallax images displayed on the LCD panel 13, and emits light in a predetermined direction corresponding to the parallax images by using the linear Fresnel lenses 121.

Description

  The present invention relates to a transmissive display device that allows an observer to observe a three-dimensional image with the naked eye.

In recent years, various display devices capable of displaying stereoscopic images have been developed.
As a method for displaying a stereoscopic image, for example, left-eye image light and right-eye image light having parallax are converted into linearly polarized light having different polarization planes, and the images reach each eye using polarized glasses. And switching between images that allow the left and right eyes to be viewed with observation glasses so that the left-eye video and the right-eye video displayed in a time-sharing manner reach the left and right eyes of the viewer, respectively. is there. However, in such a display device using glasses, there are cases where an observer feels troublesome to wear the glasses.
Therefore, for example, like the display devices disclosed in Patent Documents 1 to 4, development of a display device capable of observing a stereoscopic image with the naked eye is in progress.

Japanese Patent No. 3940456 Japanese Patent No. 3051604 Special table 2009-528565 Japanese Patent No. 4367775

However, the display devices as shown in Patent Document 1 and Patent Document 2 display a plurality of images having parallax at the same time, so that there is a problem that the resolution of the displayed stereoscopic image is lowered. In the display device of Patent Document 1, the reduction in resolution in the horizontal direction is attempted by arranging the lenticular lenses obliquely with respect to the pixel arrangement direction of the LCD panel. However, the video cannot be displayed at the original resolution of the LCD panel.
Further, in the display devices disclosed in Patent Documents 1 and 2, when a two-dimensional image is displayed, a split in which image light is intermittently emitted by a lenticular lens occurs, and image quality degradation such as a position where an image can be seen and a position where it cannot be seen occurs. Therefore, there is a problem that it is difficult to display a good two-dimensional image.

In the display device of Patent Document 3, a layer capable of refractive index modulation is provided in order to facilitate switching between a two-dimensional image and a three-dimensional image and to display a good two-dimensional image. However, even in the display device disclosed in Patent Document 3, no improvement has been made with respect to a reduction in the resolution of the video in the three-dimensional video display.
In addition, the display device of Patent Document 4 uses a parallax barrier LCD panel and a display LCD panel, and can display a good image without splitting as described above when displaying a two-dimensional image. Degradation in display resolution has not been improved.
Further, in such a display device, it is always required to reduce the weight and the thickness.

  An object of the present invention is to display a good three-dimensional image that can be observed by an observer with the naked eye, and to display a good two-dimensional image even when a two-dimensional image is displayed. Is to provide a device.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is capable of selecting and displaying a two-dimensional image or a three-dimensional image, and capable of displaying the image, and a light source unit that illuminates the transmissive display unit from the back side. (11, 21) and a lens sheet (12) disposed between the transmissive display unit and the light source unit, and having a plurality of linear Fresnel lenses (121) arranged on one surface along the sheet surface; When the 3D video is displayed, the transmissive display unit displays two or more parallax images used for the display of the 3D video while switching at a predetermined cycle. In the arrangement direction of the linear Fresnel lenses, in a region corresponding to each of the linear Fresnel lenses, there is an emission unit (112, 212) that emits a number of lights equal to the number of parallax images, and the transmissive display unit Turns off the image displayed by Synchronously with this, light is emitted from the predetermined emission unit corresponding to the parallax image, and the linear Fresnel lens emits light emitted from the light source unit in a predetermined direction corresponding to the parallax image, In the case of displaying a two-dimensional image, the transmission type display unit displays a two-dimensional image, and the light source unit emits light from all the emission units (transmission type display device) 10, 20, 30).

According to a second aspect of the present invention, in the transmissive display device according to the first aspect, the light source unit includes point light sources (112, 212) as the emission unit, and the point light sources are arranged in a matrix. The transmissive display device (10, 20, 30) is characterized in that the point light source corresponding to the parallax image displayed by the transmissive display unit is turned on.
According to a third aspect of the present invention, in the transmissive display device according to the first or second aspect, the light source unit (21) has a plurality of points according to the number of the parallax images displayed by the transmissive display unit. The transmissive display device (20) is characterized in that a light source is disposed in the vicinity of a focal position of the linear Fresnel lens (121).

According to a fourth aspect of the present invention, in the transmissive display device according to any one of the first to third aspects, the light control sheet (11) is disposed closer to the light source unit (11) than the lens sheet (12). 35) is arranged, and the light control sheet has a substantially square cross section in a cross section perpendicular to the sheet surface and parallel to the arrangement direction of the linear Fresnel lenses, and a plurality of the light control sheets are arranged along the sheet surface. Transmission comprising: a light transmission part (351); and a light absorption part (352) that is formed alternately with the light transmission part along the sheet surface in the cross section and has a function of absorbing light. Type display device (30).
According to a fifth aspect of the present invention, in the transmissive display device according to the fourth aspect, the light transmission portion (351) is a cross section in a cross section orthogonal to the sheet surface and parallel to the arrangement direction of the linear Fresnel lenses (121). The transmissive display device (30) is characterized in that the shape is a substantially trapezoidal shape in which the width on the lens sheet (12) side is wider than the width on the light source unit (11) side.
According to a sixth aspect of the present invention, in the transmissive display device according to the fourth or fifth aspect, the refractive index of the light absorbing portion (352) and the refractive index difference of the light transmissive portion (351) are equal or It is a transmission type display device characterized by being substantially equal.

  According to a seventh aspect of the invention, in the transmissive display device according to any one of the first to sixth aspects, the light is diffused to the transmissive display portion side of the lens sheet (12). And a light diffusing sheet having a haze value in the range of 5 to 70% is disposed.

According to the present invention, the following effects can be obtained.
(1) The transmissive display device of the present invention is arranged between a transmissive display unit, a light source unit, and a transmissive display unit and a light source unit, and a plurality of linear Fresnel lenses are provided on one surface along the sheet surface. When the transmissive display device including the arranged lens sheets displays a three-dimensional image, the transmissive display unit displays two or more parallax images used for displaying the three-dimensional image. The light source unit has an emission unit that emits a number of lights equal to the number of parallax images in a region corresponding to each linear Fresnel lens in the arrangement direction of the linear Fresnel lenses in the arrangement direction of the linear Fresnel lenses, and is a transmission type In synchronization with the switching of the image displayed on the display unit, light is emitted from a predetermined emission unit corresponding to the parallax image, and the linear Fresnel lens emits light emitted from the light source unit in a predetermined direction corresponding to the parallax image. To do. Further, in the transmissive display device, when a two-dimensional image is displayed, the transmissive display unit displays the two-dimensional image, and the light source unit emits light from all the emission units.

Therefore, since the light emitted from the light source unit is emitted in a predetermined emission angle direction by the linear Fresnel lens, the transmissive display device, for example, the image for the left eye that should reach the left eye reaches the right eye. The occurrence of such crosstalk is greatly reduced, and a clear three-dimensional image can be displayed without using stereoscopic glasses or the like. In addition, since this transmissive display device displays only one parallax image per frame when displaying a 3D image, the resolution of the 3D image does not deteriorate.
Further, in the transmissive display device, when displaying a two-dimensional image, the light source unit emits light from all the emitting units, and the light is converted into substantially parallel light in a substantially front direction by the lens sheet and is transmitted to the transmissive display unit. Since it is incident, it is possible to display a clear two-dimensional image that does not cause a split or the like. In addition, since the transmissive display device can use almost all the pixels of the transmissive display unit for 2D video display, the resolution of the 2D video does not deteriorate. Therefore, both 2D video and 3D video can display clear video with high resolution.
In addition, since a lens sheet with linear Fresnel lenses is used, the lens sheet is thinner and lighter than when a general-purpose lenticular lens sheet is used, making the transmissive display device thinner and lighter. it can.
In addition, since a lens sheet in which linear Fresnel lenses are arranged is used, the lens thickness is significantly smaller than a general-purpose lenticular lens sheet even when the pitch is increased, and the moldability is easy to process. Molding is also easy.

(2) The light source unit includes a point light source as an emitting unit, and the point light sources are arranged in a matrix, and the point light source corresponding to the parallax image displayed on the transmissive display unit is lit, so a clear three-dimensional Video can be displayed. In addition, a bright image can be displayed by using a light source that emits light.

(3) Since a plurality of point light sources corresponding to the number of parallax images displayed by the transmissive display unit are arranged in the vicinity of the focal position of the linear Fresnel lens, the light source unit is incident on an adjacent linear Fresnel lens or the like, Light that is emitted in a direction greatly deviating from a predetermined direction and becomes a ghost can be greatly reduced. Therefore, a clear 3D image with reduced ghost can be displayed.

(4) The light control sheet is disposed on the light source unit side of the lens sheet, and the light control sheet has a substantially square cross-sectional shape in a cross section perpendicular to the sheet surface and parallel to the arrangement direction of the linear Fresnel lenses. A plurality of light transmitting portions arranged along the sheet surface, and light absorbing portions that are alternately formed with the light transmitting portions along the sheet surface in the cross section and have an action of absorbing light. Accordingly, light that enters an adjacent linear Fresnel lens or the like, exits in a direction greatly deviating from a predetermined direction, and becomes a ghost can be reduced, and a clear three-dimensional image with reduced ghost can be displayed.

(5) The light transmitting portion has a substantially trapezoidal shape in which the cross-sectional shape in the cross section orthogonal to the sheet surface and parallel to the arrangement direction of the linear Fresnel lens is wider on the lens sheet side than on the light source unit side. The light that enters the adjacent linear Fresnel lens or the like and exits in a direction greatly deviating from a predetermined direction can be greatly reduced.

(6) Since the refractive index of the light absorbing portion and the refractive index difference of the light transmitting portion are equal or substantially equal, light can be absorbed without being totally reflected at the interface between the light transmitting portion and the light absorbing portion. . Therefore, the ghost reduction effect can be enhanced.

(7) Since a light diffusion sheet having an action of diffusing light and having a haze value in the range of 5 to 70% is disposed on the transmissive display unit side of the lens sheet, the linear Fresnel lens Moire generated due to the arrangement pitch and the arrangement pitch of the pixels of the transmissive display portion can be reduced.

It is a figure which shows the display apparatus 10 of 1st Embodiment. It is a figure explaining the shape of the linear Fresnel lens 121. FIG. In the display apparatus 10 of 1st Embodiment, it is the figure which expanded and showed a part of cross section parallel to the screen left-right direction of the lens sheet 12 and the light source part 11. FIG. It is a figure which shows the display apparatus 20 of 2nd Embodiment. It is a figure which shows the other example of the light source part 21 in the display apparatus 20 of 2nd Embodiment. In the display apparatus 20 of 2nd Embodiment, it is the figure which expanded a part of cross section parallel to the screen left-right direction of the lens sheet 12 and the light source part 21. FIG. It is a figure which shows the display apparatus 30 of 3rd Embodiment. In the display apparatus 30 of 3rd Embodiment, it is the figure which expanded a part of cross section parallel to the screen left-right direction of the lens sheet 12, the light control sheet 35, and the light source part 11. FIG. It is a figure which shows the emitted light intensity distribution in the screen left-right direction of the surface light source device (part which consists of the light source part 11 and the lens sheet 12) of Example 1. FIG. It is a figure which shows the emitted light intensity distribution in the screen left-right direction of the surface light source device (part which consists of the light source part 21 and the lens sheet | seat 12) of Example 2. FIG. The point light sources 112a and 112b of the surface light source device of Example 3 (part consisting of the light source unit 11, the light control sheet 35 and the lens sheet 12) and the surface light source device of comparative example (part consisting of the light source unit 11 and the lens sheet 12) are used. It is a figure which compares the emitted light intensity distribution in the case of lighting. It is a figure which shows an example of the deformation | transformation form of a display apparatus. In the display device of a modification, it is the figure which expanded a part of cross section parallel to the screen left-right direction of a lens sheet and a light source part. It is a figure which shows an example of the deformation | transformation form of the lens sheet.

Embodiments of the present invention will be described below with reference to the drawings.
In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
In addition, the terms “plate”, “sheet”, “film” and the like are used, but these are generally used in the order of thickness, “plate”, “sheet”, “film”. I am using it. However, since there is no technical meaning in such proper use, the claims and the description of the present specification are used in a unified manner by the description of a sheet. Accordingly, the terms “sheet”, “plate”, and “film” can be appropriately replaced. For example, the optical sheet may be an optical film or an optical plate.
Furthermore, numerical values such as dimensions and material names of each member described in the present specification are examples of the embodiment, and the present invention is not limited thereto, and may be appropriately selected and used.

(First embodiment)
FIG. 1 is a diagram illustrating a display device 10 according to the first embodiment. FIG. 1A is a diagram illustrating the configuration of the display device 10, and FIG. 1B is a diagram illustrating a state in which a part of the light source unit 11 is viewed from the front direction.
The display device 10 is a liquid crystal transmissive display device including a light source unit 11, a lens sheet 12, an LCD (Liquid Crystal Display) panel 13, and a control unit 14. The display device 10 can display an image displayed on the LCD panel 13 by illuminating from the back side with light emitted from the light source unit 11 and transmitted through the lens sheet 12.
The display device 10 can switch between 2D video display and 3D video display according to an instruction from the control unit 14.

The LCD panel 13 is a liquid crystal transmissive display unit that displays an image. The LCD panel 13 is a substantially rectangular member having a substantially rectangular shape, and for example, an observation screen having a diagonal screen size of 42 inches (929.8 mm × 523.0 mm) and a resolution of 1920 × 1080 pixels is used. it can. Note that the screen size and resolution are merely examples, and are not limited thereto.
In the following description, the direction parallel to the short side of the observation screen (LCD panel 13) in the usage state of the display device 10 is the screen vertical direction (screen vertical direction) in the usage state, and the direction parallel to the long side is the usage state. The left-right direction of the screen (the horizontal direction of the screen). Further, in the following description, unless otherwise specified, it is assumed that the screen horizontal direction and the screen vertical direction are the screen horizontal direction and the screen vertical direction when the display device 10 is used.
The LCD panel 13 switches between 2D video display and 3D video display according to an instruction from the control unit 14. Note that pixels (not shown) are arranged in a matrix on the observation screen of the LCD panel 13, and three sub pixels (not shown) that display R (red), G (green), and B (blue), respectively. Dot) form one pixel (pixel).

  The LCD panel 13 sequentially switches and displays a plurality of videos having a parallax for 3D video (parallax video) at a predetermined frequency according to an instruction from the control unit 14 when displaying the 3D video. The LCD panel 13 of the present embodiment has two images for the right eye (first right eye image and second right eye image) and two left eye images (first left eye image and second left eye image). A total of four parallax images are displayed. Note that the number of parallax images displayed on the LCD panel 3 is not limited to four and may be set as appropriate.

In the light source unit 11, point light sources 112 are arranged in a matrix on a plate-like support member 111 and illuminate the LCD panel 13 from the back. As the point light source 112, an LED light source or the like is used.
As shown in FIG. 1B, a plurality of point light sources 112 of the light source unit 11 are arranged at a predetermined pitch in the horizontal direction of the screen and the vertical direction of the screen. It is assumed that the point light sources 112 of this embodiment are arranged at a pitch P1 in the horizontal direction of the screen and the vertical direction of the screen. Since the LCD panel 13 of the present embodiment displays four parallax images, the point light source 112 corresponds to this, and between the dimensions P corresponding to the width of one linear Fresnel lens 121 in the horizontal direction of the screen, Four (point light sources 112a to 112d) are arranged.
The light source unit 11 turns on all the point light sources 112 according to an instruction from the control unit 14 when displaying a two-dimensional image. Further, the light source unit 11 repeats light emission and extinguishing of the corresponding point light source 112 in accordance with the instruction of the control unit 14 for switching the parallax image displayed on the LCD panel 13 for the 3D video display. In the present embodiment, corresponding to each parallax image, the light is sequentially turned on or off for each column extending in the vertical direction of the screen in the horizontal direction of the screen.

The lens sheet 12 is disposed on the observation surface side from the light source unit 11 (on the back side from the LCD panel 13). The lens sheet 12 is formed by arranging a plurality of linear Fresnel lenses (cylinder Fresnel lenses) 121 in one direction along the sheet surface on the surface of the base material layer 122 on the observation surface side.
The base material layer 122 is a sheet-like member having optical transparency, and is a layer serving as a base for forming the linear Fresnel lens 121. As the base material layer 122, a sheet-like member made of a thermoplastic resin or the like can be used. The linear Fresnel lens 121 is formed on the surface on the emission side of the base material layer 122.

FIG. 2 is a diagram for explaining the shape of the linear Fresnel lens 121. FIG. 2 shows an enlarged view of a cross section parallel to the arrangement direction of the linear Fresnel lenses 121 and orthogonal to the sheet surface.
Here, the sheet surface indicates a surface that is a planar direction of the sheet when viewed as the entire sheet in each sheet, and the same definition also in the present specification and claims. It is used as. For example, the sheet surface of the lens sheet 12 is a surface in the planar direction of the lens sheet 12 when viewed as the entire lens sheet 12, and is a surface parallel to the incident surface of the lens sheet 12 (surface on the light source unit 11 side). It is.

The linear Fresnel lens 121 has a lens structure that is optically equivalent to a cylindrical lens 921 having a substantially cylindrical shape whose sectional shape is shown in FIG. The linear Fresnel lens 121 has the same arrangement pitch P (width in the arrangement direction) as the cylindrical lens 921, and the contour of the lens surface of the cylindrical lens 921 is divided into a plurality in the arrangement direction of the cylindrical lens 921. A plurality of unit lenses 121a having the lens surface 121b are arranged in the arrangement direction.
The plurality of unit lenses 121a constituting the linear Fresnel lens 121 may have the same lens height ha (linear Fresnel lens 121-1) as shown in FIG. 2 (a), or FIG. 2 (b). As shown, the pitch Pa in the arrangement direction may be equal (linear Fresnel lens 121-2). As an example, the lens sheet 12 of the present embodiment will be described as having the same lens height ha as shown in FIG. 2A, but is not limited thereto. Further, the number of unit lenses 121a forming the linear Fresnel lens 121 may be appropriately selected.

The linear Fresnel lenses 121 are arranged in the horizontal direction of the screen with the vertical direction of the screen being the longitudinal direction, and the arrangement pitch (width in the arrangement direction) is P.
The linear Fresnel lens 121 is made of an ultraviolet curable resin. The linear Fresnel lens 121 is cured by dropping an ultraviolet curable resin between the base material layer 122 and a mold for molding the linear Fresnel lens 121, pressing the base material layer 122 against the mold, and irradiating the ultraviolet light. Then, it is formed by releasing from the mold. The linear Fresnel lens 121 is not limited to the ultraviolet curable resin, and may be molded using another ionizing radiation curable resin such as an electron beam curable resin.

As described above, the linear Fresnel lens 121 is optically equivalent to the cylindrical lens shown in FIG. 2A and has the same arrangement pitch. However, the thickness of the lens portion is larger than that of the cylindrical lens shown in FIG. Thin.
Therefore, the cutting work of the mold used for molding is easy, the curability of the ultraviolet curable resin or the like when molding the linear Fresnel lens 121 is good, and the amount of resin to be used can be reduced. Further, after the linear Fresnel lens 121 is formed on the roll-shaped base material layer 122, winding or the like can be easily performed. Therefore, the lens sheet 12 can be manufactured inexpensively and easily.
Further, since the linear Fresnel lens 121 is thinner than the cylindrical lens 921, the lens sheet 12 can be made thinner and lighter, and the display device can be made thinner and lighter.
In addition, this lens sheet 12 is good also as a form which joined the glass substrate to the light source part 11 side of the base material layer 122 via the joining layer.
The lens sheet 12 is not limited to the ultraviolet molding method as described above, and may be formed by an injection method, a casting method, or the like.

  The control unit 14 instructs the LCD panel 13 to switch between 2D video display and 3D video display in response to an input from an input unit (not shown). The instruction is performed while synchronizing the switching of the display of the plurality of 13 parallax images and the switching of turning on and off of the point light sources 112a to 112d of the light source unit 11.

FIG. 3 is an enlarged view of a part of a cross section of the lens sheet 12 and the light source unit 11 parallel to the left-right direction of the screen in the display device 10 according to the first embodiment. 3A to 3D show cases where the point light sources 112a to 112d are turned on, respectively. In FIG. 3, in order to facilitate understanding, the linear Fresnel lens 121 and the base material layer 122 of the lens sheet 12 are shown as having the same refractive index.
The LCD panel 13 and the light source unit 11 according to the present embodiment display the first left eye image when the point light source 112a is turned on and the second left eye when the point light source 112b is turned on according to an instruction from the control unit 14. A second right-eye image is displayed when the point light source 112c is lit, and a first right-eye image is displayed when the point light source 112d is lit.

That is, when the LCD panel 13 displays the first left-eye image in accordance with an instruction from the control unit 14, as shown in FIG. 3A, the light source unit 11 turns on the point light source 112a in accordance with the parallax image. And turn off the other point light sources 112b to 112d. Therefore, the light emitted from the point light source 112 a is incident on the lens sheet 12.
As shown by an arrow in FIG. 3A, the light incident on the lens sheet 12 is, for example, from the linear Fresnel lens 121 corresponding to the point light source 112a, for example, by the observer O with respect to the screen front direction in the screen left-right direction. The light is emitted in the range of about 5 to 15 ° with the direction of about 10 ° to the left as a peak. At this time, since the LCD panel 13 displays the first left-eye image, the light of the first left-eye image is about 5 to 15 with the peak at about 10 ° to the left as viewed from the observer O. It is emitted within the range of °.

  Similarly, when the LCD panel 13 displays a second left-eye image based on an instruction from the control unit 14, the light source unit 11 corresponds to the second left-eye image as shown in FIG. The light source 112b is turned on, and the other point light sources 112a, 112c, and 112d are turned off. The light emitted from the point light source 112b is incident on the lens sheet 12, and is, for example, about 5 ° from the linear Fresnel lens 121 corresponding to the point light source 112b to the left side of the observer O with respect to the screen front direction in the horizontal direction of the screen. The light is emitted in the range of about 0 to 10 ° with the direction as a peak. As a result, the light of the second left-eye image is emitted in the range of about 0 to 10 ° with the peak at a direction of about 5 ° to the left as viewed from the observer O.

  Further, when the LCD panel 13 displays the second right-eye image based on the instruction from the control unit 14, as shown in FIG. 3C, the light source unit 11 is a point light source corresponding to the second right-eye image. 112c is turned on, and the other point light sources 112a, 112b, and 112d are turned off. The light emitted from the point light source 112c enters the lens sheet 12, and is, for example, about 5 ° from the linear Fresnel lens 121 corresponding to the point light source 112c to the right side of the observer O with respect to the screen front direction in the horizontal direction of the screen. The light is emitted in the range of about 0 to 10 ° with the direction as a peak. As a result, the light of the second right-eye image is emitted in the range of about 0 to 10 ° with the peak at a direction of about 5 ° to the right as viewed from the observer O.

  Further, when the LCD panel 13 displays the first right-eye image, the point light source 112d corresponding to the first right-eye image is turned on as shown in FIG. The other point light sources 112a to 112c are turned off. Then, the light emitted from the point light source 112d is incident on the lens sheet 12, and from the linear Fresnel lens 121 corresponding to the point light source 112d, for example, about 10 to the right side of the observer O with respect to the screen front direction in the screen left-right direction. The light is emitted in the range of about 5 to 15 ° with the direction of ° as a peak. As a result, the light of the first right-eye image is emitted in the range of about 5 to 15 ° with the peak at a direction of about 10 ° to the right as viewed from the observer O.

  In the above description, the display device 10 of the present embodiment indicates the main emission direction of each image light with respect to the screen front direction in the left-right direction of the screen, and the first left-eye image light is approximately 10 on the left side of the observer O. Direction, the second left-eye image light is about 5 ° on the left side of the observer O, and the second right-eye image light is about 5 ° on the right side of the observer O, the first right eye. The image light has been described with an example of about 10 ° on the right side of the observer O, but the angle of the main emission direction of the light of each parallax image is appropriately determined according to the use environment of the display device 10 and the like. It can be set.

The four parallax images displayed on the LCD panel 13 are sequentially switched at a high speed (for example, 240 Hz), the switching of the four parallax images displayed on the LCD panel 13 and the lighting of the point light sources 112a to 112d of the light source unit 11 are: This is performed in synchronization with an instruction from the control unit 14. Thus, the observer O can observe the image displayed on the observation surface of the LCD panel 13 as a three-dimensional image without using stereoscopic glasses.
Moreover, each parallax image is displayed using almost all pixels within the effective range of the LCD panel 13 in one frame, and a 3D image can be displayed without reducing the resolution of the screen of the LCD panel 13. A good 3D image can be displayed.

When the LCD panel 13 displays a 2D image, the light source unit 11 turns on all the point light sources 112 according to an instruction from the control unit 14. The light emitted from the point light source 112 passes through the lens sheet 12 and enters the LCD panel 13, and the image displayed on the LCD panel 13 can be illuminated from the back, so that a good two-dimensional image can be displayed. Therefore, the display device 10 according to the present embodiment can display one frame using all the pixels in the effective screen of the LCD panel 13 even for a two-dimensional image, so that the resolution of the two-dimensional image is not deteriorated. Can be displayed.
In addition, according to the present embodiment, an LED light source is used as the point light source 112. Since this LED light source emits light, a sufficiently bright image can be displayed even during 3D image display in which only the point light source corresponding to each parallax image is turned on.

Further, in a conventional display device capable of displaying a three-dimensional image, in which a general-purpose lenticular lens sheet is arranged on the observation surface of the display LCD panel, when displaying a two-dimensional image, image light is emitted by a unit lens (lenticular lens). The display defect such as split caused by intermittent emission of light is a problem. However, in the display device 10 of the present embodiment, since the lens sheet 12 is disposed on the back side (light source unit 11 side) from the LCD panel 13, such a split does not occur.
As described above, according to the present embodiment, a 3D image that can be observed with the naked eye by an observer can be displayed with high resolution, and splits and the like can be reduced even when 2D images are displayed. 2D images can be displayed.

In general, an LED light source has a larger outer shape than a light emitting portion even if it is a small size (see FIG. 5 and the like described later). Due to the outer dimensions, when the LED light source is arranged as four point light sources 112 in the horizontal direction of the screen as shown in FIG. 1A, the horizontal width of the screen corresponding to the four point light sources is relatively large. growing. Further, when the number of parallax images is six or eight, the number of point light sources is six or eight, and the width in the horizontal direction of the screen is further increased. Therefore, the cylindrical lenses corresponding to these point light sources have a significantly larger arrangement pitch (width in the horizontal direction of the screen) than that of a general-purpose lens sheet.
When producing a mold for molding such a large arrangement pitch of cylindrical lenses, the cutting depth of the mold (mold) increases, so that the difficulty of cutting increases, making it difficult to produce the mold. In addition, when a lens shape is formed by an ultraviolet molding method or the like using such a mold, the thickness of the lens (lens height) is large and the volume of one lens itself is large. When the cylindrical lens is molded on the roll-shaped base material layer, it may be difficult to wind up after molding, and it is difficult to produce a lens sheet. Furthermore, since the lens thickness is large, the thickness of the lens sheet itself increases, which hinders the reduction in thickness and weight of the display device.

However, in this embodiment, since the lens sheet 12 in which a plurality of linear Fresnel lenses (cylinder Fresnel lenses) 121 that are optically equivalent to the cylindrical lens 921 is used is used as the lens sheet 12, a general lenticular lens is used. The lens thickness (lens height) is lower than that of the sheet, the processing of the mold is easy, and the molding can be performed easily. The lens sheet 12 is thinner and lighter than a general lenticular lens sheet having a cylindrical lens having the same pitch as the linear Fresnel lens 121.
Therefore, according to the present embodiment, the problems such as the difficulty in processing the mold of the lens sheet 12 and the curability of the resin as described above can be solved, and the lens sheet 12 can be easily manufactured at low cost. The device 10 can also be reduced in thickness and weight.

(Second Embodiment)
FIG. 4 is a diagram illustrating the display device 20 according to the second embodiment. 4A is a diagram illustrating the configuration of the display device 20, and FIG. 4B is a diagram of a part of the light source unit 21 as viewed from the front.
In the display device 20 of the second embodiment, the point light sources 212 are arranged in the vicinity of the focal point of the linear Fresnel lens 121 in the normal direction of the sheet surface and the horizontal direction of the screen (the arrangement direction of the linear Fresnel lens 121). The display device 10 is substantially the same as the display device 10 of the first embodiment except that it is different from the display device 10 of the first embodiment. Therefore, parts having the same functions as those of the first embodiment are denoted by the same reference numerals or the same reference numerals at the end thereof, and repeated description is appropriately omitted.
The display device 20 is a liquid crystal transmission display device including a light source unit 21, a lens sheet 12, an LCD panel 13, and a control unit 14. The display device 20 illuminates the image displayed on the LCD panel 13 from the back side with light emitted from the light source unit 21 and transmitted through the lens sheet 12, thereby displaying a 2D image and a 3D image. Display is possible.

The light source unit 21 includes a support member 111 and a point light source 212. On the surface of the plate-like support member 111 on the observation surface side (LCD panel 13 side), the point light source 212 is in the normal direction of the sheet surface. In the horizontal direction of the screen, the linear Fresnel lens 121 is arranged in the horizontal direction at a position near the focal point. The light source unit 21 is a light source device that illuminates the LCD panel 13 from the back side. As the point light source 212, an LED light source or the like is used.
In the present embodiment, four point light sources 212 are arranged adjacent to each other in the horizontal direction of the screen to form a set of point light source units 213. The number of point light sources 212 forming the set of point light source units 213 is equal to the number of parallax images displayed on the LCD panel 13 (four in this embodiment). A plurality of the point light source units 213 are arranged on the support member 111 in the vertical direction of the screen and the horizontal direction of the screen at positions near the focal position of the linear Fresnel lens 121 in the normal direction of the sheet surface and in the horizontal direction of the screen. Yes.

FIG. 5 is a diagram illustrating another example of the light source unit 21 in the display device 20 according to the second embodiment. 5A shows a state in which the lens sheet 12 and a part of the light source unit 21 are observed from the front direction of the screen, and FIG. 5B is parallel to the horizontal direction of the screen and the observation surface (of the lens sheet 12). A part of a cross section orthogonal to the sheet surface is shown enlarged.
In the present embodiment, as shown in FIG. 4B, the point light sources 212a to 212d constituting the point light source unit 213 are illustrated as being arranged in a line adjacent to each other in the horizontal direction of the screen. For example, as shown in FIG. 5, in the horizontal direction of the screen, each point light source 212 is arranged in a stepwise manner in the vertical direction of the screen at a position near the focal position of the linear Fresnel lens 121. A row formed by the point light sources 212 of 213 may form an angle with respect to the horizontal direction of the screen.
When an LED or the like is used for the point light source 212, as shown in FIG. 5A, the outer shape thereof is larger than the light emitting portion e, and the light emitting portion e is located near the focal position of the linear Fresnel lens 121 as shown in FIG. As described above, it may be difficult to arrange the screens closely in the horizontal direction of the screen. In such a case, the light emitting portion e of each point light source 212 of the point light source unit 213 can be arranged near the focal position of the linear Fresnel lens 121 by using an arrangement method as shown in FIG.

FIG. 6 is an enlarged view of a part of a cross section of the lens sheet 12 and the light source unit 21 parallel to the horizontal direction of the screen in the display device 20 of the second embodiment. In FIG. 6, as an example, the LCD panel 13 displays a second left-eye image and the point light source 212b is turned on. In FIG. 6, for easy understanding, the linear Fresnel lens 121 and the base material layer 122 of the lens sheet 12 are shown as having the same refractive index.
When the LCD panel 13 displays the second left-eye image, the light source unit 21 turns on the point light source 212b and other point light sources 212a, 212c, and 212d according to an instruction from the control unit 14, as shown in FIG. Turns off. The light emitted from the point light source 212b is incident on the lens sheet 12, and is about 0 with a peak of about 2 ° from the corresponding linear Fresnel lens 121 to the left side of the observer O with respect to the front direction of the screen in the horizontal direction of the screen. It emits within the range of ~ 7 °. Further, the other point light sources 21a, 212c, and 212d also emit in predetermined directions.

In the three-dimensional video display, the light source unit 21 sequentially receives each point in synchronization with the switching of the four parallax images displayed on the LCD panel 13 as in the first embodiment described above according to an instruction from the control unit 14. The light sources 212a to 212d are repeatedly turned on and off. Therefore, the display device 20 can display a good 3D image without reducing the resolution and without the observer O using stereoscopic glasses or the like.
On the other hand, at the time of two-dimensional video display, the light source unit 21 turns on all the point light sources 212 according to an instruction from the control unit 14. The light emitted from the light source unit 21 passes through the lens sheet 12 and illuminates the two-dimensional image displayed on the LCD panel 13 from the back. Therefore, the display device 20 can display a good two-dimensional image without causing a display defect such as splitting and without reducing the resolution.

From the above, according to the present embodiment, it is possible to display a good three-dimensional video that can be observed with the naked eye and a good two-dimensional video that does not have a display defect such as split without reducing the resolution.
In addition, according to the present embodiment, the point light source unit 213 is located in the vicinity of the focal position of the linear Fresnel lens 121, so that when the three-dimensional image is displayed, the light emitted from the point light sources 212a to 212d corresponds to the corresponding linear Fresnel lens. The amount of light incident on another linear Fresnel lens other than 121 (for example, another linear Fresnel lens 121 adjacent to the corresponding linear Fresnel lens 121) and emitted in a direction greatly deviating from the desired direction can be greatly reduced. Therefore, it is possible to reduce the ghost as much as possible and display a brighter three-dimensional image.

(Third embodiment)
FIG. 7 is a diagram illustrating the display device 30 according to the third embodiment. 7A is a diagram illustrating the configuration of the display device 30, and FIG. 7B is an enlarged view of a part of the cross section of the light control sheet 35 in the horizontal direction of the screen.
The display device 30 according to the third embodiment shown in FIG. 7 is different from the display device 10 according to the first embodiment described above in that a light control sheet 35 is provided between the light source unit 11 and the lens sheet 12. Except for this, it is substantially the same as the display device 10 of the first embodiment. Therefore, parts having the same functions as those of the first embodiment are denoted by the same reference numerals or the same reference numerals at the end thereof, and repeated description is appropriately omitted.
The display device 30 is a liquid crystal transmissive display device including the light source unit 11, the lens sheet 12, the light control sheet 35, the LCD panel 13, and the control unit 14. The display device 30 illuminates the image displayed on the LCD panel 13 from the back side with the light emitted from the light source unit 11 and transmitted through the light control sheet 35 and the lens sheet 12, thereby providing a two-dimensional image or a three-dimensional image. Display the video display.

As shown in FIG. 7B, the light control sheet 35 includes a light control sheet base material layer 353, a light transmission part 351, and a light absorption part 352, which are orthogonal to the sheet surface, In a cross section parallel to the direction (arrangement direction of the linear Fresnel lens 121), the light transmitting portions 351 and the light absorbing portions 352 are alternately arranged along the sheet surface.
The light control sheet base material layer 353 is a sheet-like member having light transmittance, and is a layer serving as a base of the light control sheet 35. The light control sheet base material layer 353 of the present embodiment uses a sheet-like member made of a thermoplastic resin.

  The light transmission part 351 is provided on the light source part 11 side (rear side) of the light control sheet base layer 353, is orthogonal to the sheet surface of the light control sheet 35, and is in the horizontal direction of the screen (the arrangement direction of the linear Fresnel lenses 121). The cross-sectional shape in the parallel cross-section is a substantially trapezoidal shape in which the width on the observation surface side is wider than the width on the light source unit 11 side. The light absorbing portion 352 has a substantially wedge-shaped cross section in a cross section perpendicular to the sheet surface of the light control sheet 35 and parallel to the horizontal direction of the screen, and is formed alternately with the light transmitting portions 351 along the screen surface. . In addition, as shown in FIG.7 (b), the light absorption part 352 of this embodiment is a substantially isosceles triangle shape by which the cross-sectional shape in the above-mentioned cross section makes the light source part 11 side the bottom face side. The pitch at which the light absorbing portions are arranged is equal to or less than the arrangement pitch P of the linear Fresnel lenses 121.

The light transmitting portion 351 is made of an ultraviolet curable resin having light transmittance, and the light absorbing portion 352 has an action of absorbing light, and is made of, for example, an ultraviolet curable resin containing a black pigment or the like. The light transmission part 351 and the light absorption part 352 have the same refractive index.
The thickness of the light control sheet 35 is T3, the height of the light transmission part 351 is h31, the arrangement pitch of the light absorption parts 352 is P3 (where P3 ≦ P), and the thickness direction of the light control sheet 35 The height of the light absorption part 352 at h is h32 and the width of the base is W.

  FIG. 8 is an enlarged view of a part of a cross section of the lens sheet 12, the light control sheet 35, and the light source unit 11 parallel to the left-right direction of the screen in the display device 30 of the third embodiment. In FIG. 8, as an example, the LCD panel 13 displays a second left-eye image and the point light source 112b is turned on. In FIG. 8, for easy understanding, each part of the lens sheet 12 (linear Fresnel lens 121, base material layer 122) and each part of the light control sheet 35 (light control sheet base material layer 353, light transmission part 351, light Absorbers 352) are all shown to have the same refractive index.

For three-dimensional video display, the light source unit 11 sequentially instructs each point light source 112a in synchronization with the switching of the parallax video displayed on the LCD panel 13 as in the first embodiment described above according to an instruction from the control unit 14. Repeats ~ 112d light emission and extinction.
When the LCD panel 13 displays the second left-eye image, the light source unit 11 turns on the point light source 112b and other point light sources 112a, 112c, and 112d in accordance with an instruction from the control unit 14 as shown in FIG. Turns off. The light emitted from the point light source 112b is incident on the lens sheet 12, and the peak is about 5 ° from the corresponding linear Fresnel lens 121 to the left side of the observer O with respect to the front direction of the screen in the horizontal direction of the screen. It emits within the range of 0-10 °. In addition, light from other point light sources 112a, 112c, and 112d is also emitted in predetermined directions.
At this time, since the light emitted from the point light source 112 is generally diffused light, the light is emitted not only from the corresponding linear Fresnel lens 121 but also from the adjacent linear Fresnel lens 121 in a direction significantly different from the desired direction. There is a case.
However, by using the light control sheet 35, it is possible to absorb such light (for example, light Ld in FIG. 8), and to reduce ghosts and the like that are caused by such light as stray light.

  On the other hand, at the time of two-dimensional image display, the light source unit 11 turns on all the point light sources 112 according to an instruction from the control unit 14. The light emitted from the light source unit 11 is made into substantially parallel light in the substantially front direction by the lens sheet 12 and enters the LCD panel 13 to illuminate the displayed two-dimensional image from the back. Therefore, the display device 30 can display a good two-dimensional image without causing a display defect such as a split and without reducing the resolution.

  Therefore, according to the present embodiment, it is possible to reduce the ghost without reducing the resolution, display a good 3D image that can be observed by the observer O with the naked eye, and to display a good 2 without a display defect such as split. Dimensional images can be displayed.

Examples of each embodiment will be described below.
Example 1
The display device 10 of Example 1 corresponds to the example of the display device 10 of the first embodiment shown in FIG.
The LCD panel 13 of Example 1 has an effective screen size of 42 inches wide, FHD (full high definition), a pitch of one pixel (RGB 1 set) is 484.5 μm, and its resolution is 1920 × 1080 pixels. The pixel arrangement pitch in the horizontal direction of the screen and the vertical direction of the screen is 0.4845 mm.
The light source unit 11 of the first embodiment is an LED light source that emits white light as a point light source 112 (NSSW206AT, manufactured by Nichia Corporation, case outer shape: 3.8 mm × 0.6 mm × 1.0 mm, outer shape φ of the light emitting portion = 350 μm) is used.

The linear Fresnel lens 121 of the lens sheet 12 of Example 1 is optically equivalent to a cylindrical lens having a radius of curvature of 15.09 mm and an arrangement pitch (lens width in the arrangement direction) P of 2.4 mm. The linear Fresnel lens 121 has a form in which the heights ha of the plurality of unit lenses 121a constituting the linear Fresnel lens 121 are substantially equal. The linear Fresnel lens 121 is made of an ultraviolet curable resin and has a refractive index of 1.55.
The base material layer 122 of the lens sheet 12 is made of an acrylic resin, has a refractive index of 1.49, and a thickness of 7.5 mm.
The linear Fresnel lens 121 is formed by dropping an ultraviolet curable resin between the base material layer 122 and a mold for molding the linear Fresnel lens 121, pressing the base material layer 122 against the metal mold, and irradiating with ultraviolet light. After being cured (1000 mJ / cm ² , λ = 365 nm), it is formed by releasing from the mold.

  In accordance with an instruction from the control unit 14, four parallax images are sequentially displayed on the LCD panel 13, and each parallax image is switched at 240 Hz. In addition, the control unit 14 controls the turning on and off of each point light source 112 of the light source unit 11 in synchronization with the switching of the video display on the LCD panel 13.

FIG. 9 is a diagram illustrating a light emission intensity distribution in the left-right direction of the screen of the surface light source device of the first embodiment (a portion including the light source unit 11 and the lens sheet 12). The vertical axis in FIG. 9 is the relative intensity, and the horizontal axis is the emission angle in the horizontal direction of the screen (the emission angle with respect to the sheet surface of the lens sheet 12). The minus direction on the horizontal axis is the left direction of the screen when viewed from the observer O, and the positive direction of the horizontal axis is the right direction of the screen when viewed from the observer O. The emission intensity distribution of the light shown in FIG. 9 was obtained by simulation using the surface light source device of Example 1 (part consisting of the light source unit 11 and the lens sheet 12).
In the simulation of the surface light source device of Example 1, a transparent glass plate (not shown) having a predetermined thickness (3 mm) is disposed between the light source unit 11 and the lens sheet 12, and one of the glass plates. The lens sheet 12 is disposed on the surface (the surface on the observer O side), and the light source unit 11 (the point light source 112) is disposed on the other surface (the surface on the back side) of the glass substrate. Assumed.

As shown in FIG. 9, the light emitted from the point light sources 112a to 112d is emitted in directions in which the emission angle is about −10 °, the emission angle is about −3 °, the emission angle is + 3 °, and the emission angle is + 10 °, respectively. doing. Note that the peak direction of the emission angle is not a mere peak of relative intensity but takes the peak of the center of the band in consideration of the band of the emitted light.
Thereby, as for the three-dimensional image displayed by the display apparatus 10 of Example 1, each parallax image is mainly emitted in each emission angle direction, and these parallax images are switched by restriction. A clear three-dimensional image that can be clearly observed with the naked eye and has high resolution can be displayed without using glasses or the like.

  When the 3D image was actually displayed on the display device 10 of Example 1 and observed, a good 3D image was observed without using stereoscopic glasses or the like and without reducing the resolution of the image. It was. In addition, the display device 10 of Example 1 observed a good image without reducing the resolution and display defects such as splitting even when displaying a two-dimensional image.

(Example 2)
The display device 20 of Example 2 is an example of the display device 20 of the second embodiment shown in FIG.
The display device 20 of the second embodiment uses the same LED as that of the first embodiment as a point light source. As illustrated in FIG. 5, the point light sources 212 a to 212 d of the point light source unit 213 are each point light sources (LEDs). The light source) is shifted one by one in the vertical direction of the screen, and is arranged so as to be shifted by the shape of the light emitting portion e (outside diameter φ = 350 μm) in the horizontal direction of the screen, and is arranged near the focal point of the linear Fresnel lens 121. did.

The linear Fresnel lens 121 of the lens sheet 12 is optically equivalent to a cylindrical lens having a radius of curvature of 1.63 mm and an arrangement pitch (lens width in the arrangement direction) P of 2.68 mm. The linear Fresnel lens 121 has a form in which the heights ha of the plurality of unit lenses 121a constituting the linear Fresnel lens 121 are substantially equal. The linear Fresnel lens 121 is made of an ultraviolet curable resin and has a refractive index of 1.55.
The base material layer 122 is made of PET resin (Cosmo Shine, A4300) and has a thickness of 0.25 mm.
The LCD panel 13 according to the second embodiment has the same specifications as the LCD panel 13 according to the first embodiment.

  FIG. 10 is a diagram illustrating a light emission intensity distribution in the left-right direction of the screen of the surface light source device of the second embodiment (a portion including the light source unit 21 and the lens sheet 12). The vertical axis in FIG. 10 is the relative intensity, and the horizontal axis is the emission angle in the horizontal direction of the screen (the emission angle with respect to the sheet surface of the lens sheet 12). The minus direction on the horizontal axis is the left direction of the screen when viewed from the observer O, and the positive direction of the horizontal axis is the right direction of the screen when viewed from the observer O. The light emission intensity distribution shown in FIG. 10 was obtained by simulation in the surface light source device of Example 2, similarly to the light emission intensity distribution of the surface light source device of Example 1 described above.

As shown in FIG. 10, the light emitted from the point light sources 212a to 212d has directions where the emission angle is about −5 °, the emission angle is about −2 °, the emission angle is about + 2 °, and the emission angle is about + 5 °, respectively. Is emitted. Note that the peak direction of the emission angle is not a mere peak of relative intensity but takes the peak of the center of the band in consideration of the band of the emitted light.
Thereby, the 3D image displayed by the display device 20 according to the second embodiment emits each parallax image in each emission angle direction, and these parallax images are switched by restriction. And the like can be clearly observed with the naked eye, and a clear three-dimensional image with high resolution can be displayed.

  Actually, when a 3D image was displayed by the display device 20 of Example 2, a good 3D image with high resolution was observed with the naked eye. Actually, when a two-dimensional image was displayed by the display device 20 of Example 2, a good two-dimensional image with high resolution and no split was observed.

Further, in the light emission intensity distribution of the second embodiment shown in FIG. 10, the light intensity peak generated in a direction other than the predetermined peak intensity as compared with the light emission intensity distribution of the first embodiment shown in FIG. 9 described above. Has been greatly reduced. If the intensity of the light that forms an intensity peak that occurs in a direction deviating from the desired direction is large, it is observed as a ghost when the display device is observed from a certain angle, and the three-dimensional image is unclear. As a result, the image quality is degraded.
However, in the surface light source device of the second embodiment, stray light causing such a ghost is greatly reduced, and the display device 20 of the second embodiment has a better three-dimensional image in which the ghost is greatly improved. Can be displayed.

(Example 3)
The display device 30 of Example 3 is an example of the display device 30 of the third embodiment shown in FIG. In the display device 30 of Example 3, the light source unit 11, the LCD panel 13, and the lens sheet 12 all have the same specifications as the display device 10 of Example 1.
The light control sheet 35 has a thickness T3 = 358 μm, a height h31 = 170 μm of the light transmission part 351, an arrangement pitch P3 = 60 μm of the light absorption part 352, a width W of the bottom side of the light absorption part 352 = 28 μm, and light. The height h32 of the absorber 352 is 150 μm.

Here, the surface light source device of Example 3 (the portion including the light source unit 11, the light control sheet 35, and the lens sheet 12) and the surface light source device of the comparative example that does not include the light control sheet 35 (the light source unit 11, the lens sheet). The emission intensity distribution of the light with the portion consisting of 12) was compared by simulation.
The surface light source device of Example 3 corresponds to a form in which a light control sheet 35 is further provided between the light source unit 11 and the lens sheet 12 of the surface light source device of Example 1. Here, the surface light source device of Example 3 includes a transparent glass plate (not shown) on the surface of the lens sheet 12 on the light source unit 11 side, and a gap exists between the glass plate and the light control sheet 35. Simulation is performed on the assumption of the form. In the surface light source device of the third embodiment, the distance from the point light source 112 to the lens sheet 12 is the same as that of the surface light source device of the first embodiment. In the surface light source device of Example 3, the thickness of a glass plate (not shown) arranged between the lens sheet 12 and the light control sheet 35 is arranged between the light source unit 11 and the lens sheet 12 in Example 1. It was made thinner than the glass plate. Further, the surface light source device of the comparative example is in the same form as the surface light source device of the third embodiment and does not include the light control sheet 35 (a space between the glass plate and the light source unit 11). A simulation was performed.

FIG. 11 shows points of the surface light source device of Example 3 (portion consisting of the light source unit 11, the light control sheet 35 and the lens sheet 12) and the surface light source device of Comparative Example 1 (portion consisting of the light source unit 11 and the lens sheet 12). It is a figure which compares the emitted light intensity distribution when the light sources 112a and 112b (refer FIG. 8) are lighted. The vertical axis in FIG. 11 is the relative intensity, the horizontal axis is the outgoing angle in the horizontal direction of the screen (the outgoing angle with respect to the sheet surface of the lens sheet 12), and the negative direction of the horizontal axis is the screen viewed from the observer O. It is the left direction, and the plus direction on the horizontal axis is the right direction of the screen when viewed from the observer O.
In the surface light source device of Example 3, the light emitted from the point light sources 112a and 112b is emitted with the emission angle of about −9 ° and the emission angle of about −3 ° as the peak directions, respectively.
Further, as shown in FIG. 11, in the surface light source device of Example 3 including the light control sheet 35, the set emission intensity peak is higher than that of the comparative surface light source device not including the light control sheet 35. The intensity peak generated in the direction greatly deviating from the direction becomes significantly reduced. Therefore, the display device 30 according to the third embodiment can display a good three-dimensional image in which stray light is greatly reduced and the ghost reduction effect is high, in addition to the effects exhibited by the display device 10 according to the first embodiment.

From the above, according to the display device of each embodiment, both the 3D video and the 2D video can display one frame image by using almost all the pixels in the effective screen of the LCD panel 13, so that the resolution can be reduced. Good video can be displayed without dropping.
Moreover, according to the display device of each embodiment, stereoscopic glasses or the like is not necessary, and the observer O can observe a three-dimensional image with the naked eye. And can comfortably observe a good 3D image.
Furthermore, according to the second embodiment and the third embodiment, a ghost caused by stray light can be greatly reduced, and a clearer three-dimensional image can be provided.
In addition, according to the display device of each embodiment, display defects such as splits that have occurred during 2D image display in the conventional display device in which the lens sheet 12 is arranged on the viewer side from the LCD panel 13 do not occur. The display defect at the time of 2D video display is greatly improved, and a good 2D video can be displayed.

  In addition, in each embodiment, since the lens sheet 12 in which a plurality of linear Fresnel lenses (cylinder Fresnel lenses) 121 are arranged is used as the lens sheet 12, it is difficult to process the mold of the lens sheet 12 and the resin at the time of molding. The lens sheet 12 can be easily produced at low cost, and the display device 10 can be made thinner and lighter.

(Deformation)
Without being limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.

(1) In the first and third embodiments, the example using the light source unit 11 in which the point light sources 112 are arranged as the light source unit 11 has been shown, but not limited thereto, the parallax LCD panel 412, the surface light source unit 411, You may use the light source part 41 provided with.
FIG. 12 is a diagram illustrating an example of a modification of the display device. FIG. 12A is a diagram for explaining the configuration of a modified display device 40, and FIG. 12B is a diagram of a part of the dots on the parallax LCD panel 412 of the light source unit 41 as viewed from the front. It is. FIG. 12A shows a state in which the lens sheet 42 and the parallax LCD panel 412 are arranged at a predetermined distance in the thickness direction, but the glass substrate on the emission side of the parallax LCD panel 412 is shown. It is good also as a form arrange | positioned in contact with 414. FIG.
The display device 40 of this modification is substantially the same as the display device 10 of the first embodiment described above except that the light source unit 41 is provided and the lens sheet 42 is provided with a glass substrate 424. Therefore, parts having the same functions as those of the first embodiment described above are denoted by the same reference numerals or the same reference numerals at the end thereof, and repeated description is appropriately omitted.

In the lens sheet 42, a plurality of linear Fresnel lenses 121 are arranged on the exit side surface of the base material layer 122, and a glass substrate 424 is joined to the entrance side of the base material layer 122 via a joining layer 423.
The bonding layer 423 is a layer that bonds the surface on the light source unit 41 side (back side) of the base material layer 122 and the surface on the observation surface side of the glass substrate 424. As the bonding layer 423, for example, a pressure sensitive adhesive, an ultraviolet curable pressure sensitive adhesive, an adhesive, or the like is used.
The glass substrate 424 is disposed closest to the light source unit 41 of the lens sheet 42. In the glass substrate 424, when the lens sheet 12 and the parallax LCD panel 412 are laminated, the position of the focal point of the linear Fresnel lens 121 in the normal direction of the sheet surface is the position of the pixel of the parallax LCD (liquid crystal The thickness thereof is designed so as to substantially coincide with the position of the layer 115.
In addition, the lens sheet 42 is good also as a form which is not provided with the glass substrate 424 like the lens sheet 12 of above-mentioned Embodiment 1. FIG.

The light source unit 41 is a device that emits light that illuminates the LCD panel 13 from the back. The light source unit 41 of this embodiment includes a surface light source unit 411 and a parallax LCD panel 412.
The surface light source unit 411 emits light in a planar shape, and illuminates the parallax LCD panel 412 from the back surface. As the surface light source unit 411, for example, a direct type surface light source device, an edge light type surface light source device, or the like can be used. The surface light source unit 411 may use a line light source such as a cold cathode tube, a point light source such as an LED (Light Emitting Diode), or an organic EL (Electro Luminescence) or an inorganic EL as a light source that emits light. A simple surface light source may be used.

  The parallax LCD panel 412 is a substantially flat member including two glass substrates 413, 414 and a liquid crystal layer 415 sealed between the two glass substrates 413, 414. It has the same screen size. When viewed from the viewing surface side, the parallax LCD panel 412 has a plurality of dots (sub-pixels) 416 arranged on its display surface, which is 5760 × 1080 dots (equivalent to 1920 × 1080 pixels). The parallax LCD panel 412 does not include a color filter or the like, and transmits light (white light) from the surface light source unit 411 from a predetermined dot according to an instruction from the control unit 14.

In the parallax LCD panel 412 of this embodiment, as shown in FIG. 12B, dots 416 are arranged in the vertical direction of the screen and the horizontal direction of the screen, and the horizontal direction of the screen is denser than the vertical direction of the screen. Is arranged. In the present embodiment, the arrangement pitch of the dots 416 in the horizontal direction of the screen is P41, and the arrangement pitch of the dots 416 in the vertical direction of the screen is P42.
The number of dots 416 is a set of four columns in the horizontal direction of the screen, and the number of columns 116 in the horizontal direction of the dots 116 in this set is the number of parallax images displayed on the LCD panel 13 (this embodiment). Then, it corresponds to 4).
The parallax LCD panel 412 receives light from the dots 416 corresponding to the parallax video displayed on the LCD panel 13 in synchronism with the switching of the parallax video display on the LCD panel 13 when the 3D video is displayed according to an instruction from the control unit 14. The other dots shield the light. The dots 416 of the present embodiment sequentially transmit or shield light for each column extending in the vertical direction of the screen in the horizontal direction of the screen. Further, when displaying a two-dimensional image, all the dots 416 transmit light.

FIG. 13 is an enlarged view of a part of the cross section of the lens sheet 42 and the light source unit 41 parallel to the left-right direction of the screen in the modified display device 40. In FIG. 13, as an example, the LCD panel 13 displays a second left-eye image, and the dots 416 b transmit light. In FIG. 14, for easy understanding, each part of the lens sheet 42 and the glass substrate 114 of the parallax LCD panel 412 are shown as having the same refractive index.
When the LCD panel 13 displays the second left-eye image, as shown in FIG. 13, the light source unit 41 transmits light from the surface light source unit 411 through the dots 416b according to instructions from the control unit 14, and the other The dots 416a, 416c, and 416d are shielded. The light emitted from the dots 416b is incident on the lens sheet 12, and is about 0 to about 5 ° peaking from the corresponding linear Fresnel lens 121 to the left side of the observer O with respect to the front direction of the screen in the horizontal direction of the screen, for example. The light is emitted within a range of 10 °.
For three-dimensional video display, the light source unit 41 sequentially receives dots 416a in synchronization with switching of four parallax images displayed on the LCD panel 13 as in the first embodiment described above according to an instruction from the control unit 14. Repeat the transmission and shielding of light from ˜416d. Accordingly, the display device 40 can display a good 3D image without reducing the resolution and without the observer O using stereoscopic glasses or the like.
On the other hand, at the time of displaying a two-dimensional image, the light source unit 41 transmits light from the surface light source unit 411 through all the dots 416 according to an instruction from the control unit 14. The light emitted from the light source unit 41 becomes substantially parallel light in a substantially front direction by the lens sheet 42, and illuminates the two-dimensional image displayed on the LCD panel 13 from the back. Therefore, the display device 40 can display a good two-dimensional image without causing a display defect such as splitting and without reducing the resolution.

The following example is given as an example of the lens sheet 42 and the like of the display device 40 according to this modification.
The linear Fresnel lens 121 of the lens sheet 42 is optically equivalent to a cylindrical lens having a pitch P = 0.646 mm and a curvature radius of 0.750 mm. The linear Fresnel lens 121 has a form in which the heights ha of the plurality of unit lenses 121a constituting the linear Fresnel lens 121 are substantially equal. The linear Fresnel lens 121 is made of an ultraviolet curable resin (urethane acrylate resin), and its refractive index is 1.55. The base material layer 122 is made of PET resin and has a thickness of 0.1 mm. The base material layer 122 on which the linear Fresnel lens 121 is formed and the glass substrate 124 are bonded together by a bonding layer 423 that is a layer of an ultraviolet curable adhesive to form a lens sheet 42. The glass substrate 424 is made of glass (BK-7) having a refractive index of 1.56 (λ = 578.3 nm) and has a thickness of 2.0 mm.
The parallax LCD panel 412 has an effective screen size of 42 inches wide size (5760 × 1080 dots), an aperture ratio of 90%, a pixel (dot) arrangement pitch P41 in the left-right direction of the screen, 0.1615 mm, The arrangement pitch P42 of pixels (dots) in the direction is 0.4845 mm.
The surface light source unit 411 is a direct type surface light source device. The surface light source unit 411 has a Lambert distribution of ± 45 °.

As the parallax LCD panel 412, a polymer dispersed liquid crystal (PDLC) panel may be used. The polymer-dispersed liquid crystal panel is configured to switch between transmission and diffuse reflection according to an instruction from the control unit 14 without using a polarizing plate or an alignment plate. Therefore, the attenuation of the amount of light is significantly reduced as compared with the parallax LCD panel using a normal TN liquid crystal. Therefore, by using the polymer dispersed liquid crystal panel as the parallax LCD panel 412, a brighter screen can be displayed with less power. In addition, the polymer dispersion type liquid crystal panel has a high response speed and is effective when displaying more parallax images.
When an edge light type surface light source device is used for the surface light source unit 411, a prism sheet in which a plurality of unit prisms are arranged on the surface of the light guide plate may be disposed on the light exit side from the light guide plate. By arranging such a prism sheet, the light emitted from the light guide plate can be efficiently launched in the direction of the observer O.

(2) In each embodiment, the linear Fresnel lens 121 of the lens sheet 12 has been illustrated as being arranged in the horizontal direction of the screen. However, the present invention is not limited thereto. They may be arranged in the direction of α (0 ° <α <10 °). By arranging in this way, moire generated between the linear Fresnel lens 121 and the pixels of the LCD panel 13 can be reduced.

(3) In each embodiment, although the example which arrange | positions the lens sheet 12 between the LCD panel 13 and the light source parts 11 and 21 was shown, not only this but the lens sheet 12 is the lower side of the LCD panel 13, for example You may arrange | position to a polarizing plate.
FIG. 14 is a diagram illustrating an example of a modified form of the lens sheet.
As shown in FIG. 14A, a lens sheet 52 is laminated on the surface of a polarizing plate (not shown) on the light source unit 11 side of the LCD panel 13, and the linear Fresnel lens 121 is arranged in a convex shape on the light source unit 11 side. May be. The lens sheet 52 is formed, for example, by arranging a plurality of linear Fresnel lenses 121 on the incident-side surface of the base material layer 222 similar to that in the first embodiment.
Further, as shown in FIG. 14B, a lens sheet 62 having a lens shape 621 that is the reverse type of the linear Fresnel lens 121 may be laminated on the polarizing plate surface on the light source side of the LCD panel 13.

(4) In each embodiment, the light source units 11 and 21 have shown an example in which a plurality of LED light sources are arranged as the point light sources 112 and 212. However, the present invention is not limited to this, and for example, OLED (Organic Light-Emitting Diode) or PDP (Plasma Display Panel) or the like may be used as the light source unit.

(5) In each embodiment, the surface of the lens sheet 12 may be appropriately subjected to a hard coat treatment, an antireflection treatment, or the like. The antireflection treatment can be appropriately selected and used, for example, by a process such as a WET method or a DRY method, or a method for forming a moth-eye type minute shape. By applying an antireflection treatment to the surface of the lens sheet, it is possible to increase the light transmittance and display a brighter image.

(6) In each embodiment, there are four parallax images (first left-eye image, second left-eye image, second right-eye image, and first right-eye image) displayed on the LCD panel 13. Although an example has been shown, the present invention is not limited to this, and the number of parallax images displayed on the LCD panel 13 may be two, six, or the like, or may be freely set as appropriate.

(7) In each embodiment, the surface on the point light source side of the support member 111 on which the point light sources 112 and 212 are disposed may be formed in a color that absorbs light such as black. By setting it as such a structure, it can reduce significantly that the light reflected on the support member 111 surface turns into a stray light.

(8) In the third embodiment, the light transmission part 351 has an example in which the cross-sectional shape in the left-right direction of the screen is a substantially trapezoidal shape in which the width on the light source unit 11 side is smaller than the width on the lens sheet side. For example, the cross-sectional shape of the light transmission part 351 may be a substantially trapezoidal shape whose width on the light source part 11 side is larger than the width on the lens sheet 12 side, or a substantially square shape or a substantially rectangular shape. It is good also as a shape which combined the curve and the straight line, and the polygonal shape which combined the straight line and the slope became a broken line shape.
Moreover, although the refractive index of the light transmission part 351 and the light absorption part 352 showed the same example, it is not restricted to this, For example, the light transmission part 351 and the light absorption part 352 have a refractive index slightly. Also good. Further, when the refractive index of the light absorbing portion 352 is larger than the refractive index of the light transmitting portion 351, stray light can be reduced due to the stray light absorbing effect.

(9) In each embodiment, a light diffusion sheet having an action of diffusing light may be provided between the lens sheet 12 and the LCD panel 13. The light diffusion sheet has a haze value of 5 to 70%, and preferably has a diffusibility that does not significantly change the emission angle of the light emitted from the lens sheet 12.

(10) Although the light source part 11 of 3rd Embodiment showed the example provided with the supporting member 111 and the point light source 112, it is not restricted to this, For example, as the light source part 11, it shows to the above-mentioned modification (1). Alternatively, the light source unit 41 including the surface light source unit 411 and the parallax LCD panel 412 may be used.

  In addition, although this embodiment and modification can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the embodiments described above.

DESCRIPTION OF SYMBOLS 10, 20, 30 Display apparatus 11,21 Light source part 111 Support member 112,212 Point light source 12 Lens sheet 121 Linear Fresnel lens 122 Base material layer 13 LCD panel 14 Control part 35 Light control sheet

Claims (7)

2D video or 3D video can be selected and displayed,
A transmissive display unit capable of displaying images;
A light source unit that illuminates the transmissive display unit from the back side;
A lens sheet that is arranged between the transmissive display unit and the light source unit, and a plurality of linear Fresnel lenses are arranged along the sheet surface on one surface;
With
When displaying 3D video,
The transmissive display unit displays two or more parallax images used for displaying a three-dimensional image while switching at a predetermined cycle.
The light source unit includes an emission unit that emits a number of lights equal to the number of parallax images in a region corresponding to each of the linear Fresnel lenses in the arrangement direction of the linear Fresnel lenses, and the transmissive display unit Synchronously with the switching of the image to be displayed, the light is emitted from the predetermined emission unit corresponding to the parallax image,
The linear Fresnel lens emits light emitted from the light source unit in a predetermined direction corresponding to the parallax image,
When displaying 2D video,
The transmissive display unit displays a two-dimensional image,
The light source unit emits light from all the emission units;
A transmissive display device characterized by the above. The transmissive display device according to claim 1,
The light source unit includes a point light source as the emitting unit,
The point light sources are arranged in a matrix, and the point light source corresponding to the parallax image displayed by the transmissive display unit is turned on;
A transmissive display device characterized by the above. The transmissive display device according to claim 1 or 2,
In the light source unit, a plurality of point light sources corresponding to the number of parallax images displayed by the transmissive display unit are arranged in the vicinity of a focal position of the linear Fresnel lens,
A transmissive display device characterized by the above. The transmissive display device according to any one of claims 1 to 3,
A light control sheet is disposed closer to the light source unit than the lens sheet,
The light control sheet is
A cross-sectional shape in a cross section orthogonal to the sheet surface and parallel to the arrangement direction of the linear Fresnel lens is a substantially square shape, and a plurality of light transmission portions arranged along the sheet surface;
A light-absorbing part that is formed alternately with the light-transmitting part along the sheet surface in the cross section and has an action of absorbing light;
Providing
A transmissive display device characterized by the above. The transmissive display device according to claim 4,
The light transmitting portion has a substantially trapezoidal shape in which a cross-sectional shape in a cross section orthogonal to the sheet surface and parallel to the arrangement direction of the linear Fresnel lenses is wider on the lens sheet side than on the light source unit side. about,
A transmissive display device characterized by the above. The transmissive display device according to claim 4 or 5,
The refractive index of the light absorbing portion and the refractive index difference of the light transmitting portion are equal or substantially equal,
A transmissive display device characterized by the above. The transmissive display device according to any one of claims 1 to 6,
A light diffusing sheet having an action of diffusing light on the transmissive display unit side of the lens sheet and having a haze value in the range of 5 to 70%, is disposed;
A transmissive display device characterized by the above.

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