JP2010224129A - Stereoscopic image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stereoscopic image display device having high resolution and displaying a stereoscopic image having good image quality. <P>SOLUTION: The stereoscopic image display device 101 includes a lenticular lens 1, a transmission type liquid crystal panel 2, a backlight part 7, and a directivity lessening part 31 disposed in parallel with the liquid crystal panel 2. The liquid crystal panel 2 displays the stereoscopic image having parallax only in a right-and-left direction (direction Y). The backlight part 7 irradiates the liquid crystal panel 2 with a light beam having directivity in order to project the stereoscopic image to an observer. At such a time, the light beam transmitted through the liquid crystal panel 2 passes through the directivity lessening part 31, whereby the directivity of the light beam in an up-and-down direction (direction X) different from the right-and-left direction (direction Y) being the direction of parallax is lessened. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stereoscopic image display apparatus capable of observing stereoscopic images (still images and moving images) without using special glasses.

  In recent years, in the field of video display, various video providing methods have been considered. For example, stereoscopic image display devices that perceive video (moving images) in three dimensions are being put into practical use.

  The stereoscopic image display device displays an image that can be perceived stereoscopically when a person views the image. It is said that there are convergence, binocular parallax, motion parallax, and adjustment as elements that are perceived stereoscopically when a human sees an object, and a stereoscopic image display apparatus uses these elements.

  Convergence is a movement in which the left and right eyeballs face inward when looking at an object. When the brain recognizes the muscle tension that gives the eyes a vergence angle, humans get a three-dimensional effect. The binocular parallax is a deviation (so-called parallax) of an image on the retina projected onto both eyes when the gazing point is observed. Humans perceive this binocular parallax as a stereoscopic effect. Motion parallax is a change in the appearance of an object as the viewpoint moves when the viewpoint for viewing the object is changed. Humans perceive this motion parallax as a stereoscopic effect. Adjustment means that the thickness of the lens changes according to the distance of the object being viewed. When the brain recognizes muscle tension that changes the thickness of the lens, humans gain a three-dimensional effect.

  There are four types of conventional stereoscopic video devices that utilize the perceptual action that promotes stereoscopic vision: (i) binocular, (ii) multi-view, (iii) volume display, and (iv) aerial image reproduction. Can be divided roughly. The features of these systems are briefly described below.

  (I) In the binocular system, an image when viewed with the left eye and an image when viewed with the right eye are prepared, the left eye image is presented to the left eye of the observer, and the right eye is displayed. This is a method for presenting a right-eye video. The binocular system gives a stereoscopic effect mainly using convergence and binocular parallax. There are several methods for independently presenting two types of video to both eyes.

  It is well known that glasses are prepared to separate the left and right images. Specifically, there is an anaglyph type that displays the image for the left eye in red and the image for the right eye in blue, and looks through the blue / red glasses. Alternatively, there is a method in which a left-eye image and a right-eye image are alternately displayed in time, and left and right images are independently presented to an observer through glasses equipped with time-division shutters. Recently, there is a method of displaying left and right eye images by changing the polarization direction, and independently presenting the left and right images to an observer using glasses equipped with polarizing filters for separating the left and right images. This method can reduce the burden on the observer because the glasses can be made lighter than the method using the time-division shutter.

  Some independent presentation methods do not use glasses. As a method not using glasses, there is a method of separating a display image into left and right images using a parallax barrier or a lenticular lens.

  (Ii) In the multi-view type, the viewpoint is prepared in addition to the two points of the binocular type. That is, the multi-view method is a method in which left-eye video and right-eye video from a plurality of viewpoints are presented independently with respect to the viewing direction using a parallax barrier or a lenticular lens. In the multi-view system, in addition to convergence and binocular parallax, as the observation position moves, the left and right images are switched by the number of viewpoints and projected to the observer, giving the observer a stereoscopic effect due to motion parallax. Can do.

  (Iii) The volume display type is to display an image at a position corresponding to the depth by, for example, preparing a plurality of display surfaces in the depth direction or rotating the display surface. In the volume display type, in addition to convergence and binocular parallax, it is possible to create a stereoscopic effect by adjustment.

  (Iv) The aerial image reproduction method is a method of reproducing the subject's light beam itself. The aerial image reproduction method is an excellent method in that the observer can obtain any of the effects of convergence, binocular parallax, motion parallax, and adjustment, as in the case of actually viewing an object. This method includes a light beam reproduction method and holography.

  Here, the principle of stereoscopic image display by the light beam reproduction method will be briefly described with reference to FIGS.

FIG. 12 is a side view of the optical system of the stereoscopic image display apparatus using the light beam reproduction method.
FIG. 13 is a perspective view of an optical system of a stereoscopic image display apparatus using the light beam reproduction method. As shown in FIGS. 12 and 13, the stereoscopic image display device includes a display panel 112 and a lens array 113. The display panel 112 includes a plurality of pixels (reference numeral 112a in FIG. 14). As the display panel 112, for example, a liquid crystal display is used. The lens array 113 has a plurality of lenses arranged in one plane. Here, as shown in FIG. 13, an example in which a microlens array in which microlenses 113a are two-dimensionally arranged is used as the lens array 113 will be described.

  The stereoscopic image display device displays an element image 114 generated by a plurality of pixels on the display panel 112. The rays of the image of the display panel 112 obtained through the lens array 113 are as shown in the figure. When the observer observes the element image 114 displayed on the display panel 112 through the lens array 113, the reproduced image 111 exists. I feel as if. In other words, the stereoscopic image display device displays the element image 114 on the display panel 112 so that an observer who observes the element image 114 through the lens array 113 feels as if the reproduced image 111 exists. For this reason, all of the convergence, the binocular parallax, and the adjustment are given to the observer in the same manner as in a state where the object is naturally seen.

  Further, as shown in FIG. 13, each point of the image reproduced by the light beam reproduction method emits a light beam in each direction through the lens. FIG. 13 shows light rays corresponding to the point A of the reproduced image 111. For this reason, when the observation direction is changed, the observer observes an image viewed from that direction. That is, the observer feels motion parallax. In the example described here, since the stereoscopic image display apparatus uses a microlens array as the lens array 113, it is possible to give the observer motion parallax not only in the horizontal direction but also in the vertical and horizontal directions.

  Here, a range (viewing zone) in which a stereoscopic image can be seen by the light beam reproduction method will be described with reference to FIGS. 14 and 15.

  FIG. 14 is a diagram showing a viewing zone angle of light passing through one lens. As shown in FIG. 14, an element image region 115 for displaying an element image is set corresponding to one microlens 113a constituting the lens array 113. The image of the element image area 115 can be observed in an area within the viewing zone angle 116.

  FIG. 15 is a diagram illustrating a viewing zone. A region in which the element image can be observed through all the microlenses 113 a of the lens array 113 is a viewing zone 117.

  By the way, in the stereoscopic image display device, it is preferable that the region (viewing zone) where the observer can observe the stereoscopic image is wide. However, in the light beam reproduction method, it is difficult to achieve both the resolution of the stereoscopic image and the viewing zone.

  The light beam reproduction method is a method of displaying a stereoscopic image through a lens array, and an observer observes an image of 1 to 2 pixels through one lens. Therefore, the resolution of the stereoscopic image is equivalent to the resolution of the lens array. For example, if the resolution of the display panel is 200 × 200 pixels and the element image area is 10 × 10 pixels, the number of lenses in the lens array is 20 × 20. This number of lenses is equivalent to the resolution of the stereoscopic image. The number of pixels in the element image area represents the number of parallaxes that can be displayed (the number of motion parallaxes). In the case of the above example, the number of motion parallax is 10 parallaxes on the left and right and 10 parallaxes on the top and bottom.

  In order to increase the viewing zone angle of each lens in order to widen the viewing zone, it is necessary to increase the number of parallaxes, that is, the number of elemental image pixels and increase the lens area. An increase in the lens area causes a decrease in the number of lenses, so that the resolution of the stereoscopic image is reduced.

  In order to solve this problem, the number of pixels of the display panel may be increased, but there is a limit to this. For example, in order to obtain a SVGA (800 × 600 pixel) level stereoscopic image that is normal in a two-dimensional display, the number of lenses in the lens array is required to be 800 × 600, and even if the element image is 10 × 10 pixels, As a display panel, 8000 × 6000 pixels are required. However, there is currently no direct view display that can display such a display. In addition, it is not practical to develop such a display due to many technical and price issues.

  One method of displaying a high-resolution stereoscopic image is a method of displaying a right-eye image and a left-eye image in a time-sharing manner. For example, in Japanese Patent Laid-Open No. 2005-77472 (Patent Document 1), a surface light source that alternately emits first and second illumination light is disposed on the side opposite to the viewer side of the liquid crystal display panel. The intensity peak of the first illumination light exists in a direction inclined by a predetermined angle in the direction of one of the left and right eyes of the display observer with respect to the normal line of the liquid crystal display panel. The intensity peak of the second illumination light exists in a direction inclined by a predetermined angle in the direction of the other eye of the observer with respect to the normal line of the liquid crystal display panel. Then, the left eye image data and the right eye image data are alternately written into a plurality of pixels of the liquid crystal display panel by the control means. At this time, the illumination light having directivity corresponding to the image data written in the plurality of pixels of the liquid crystal display panel among the first and second illumination lights is synchronized with the writing of the image data. The light is emitted from the light source.

  As another method for displaying a high-resolution stereoscopic image, there is a one-dimensional ray reproduction method that has no parallax in the vertical direction and parallax in the horizontal direction. For example, Japanese Patent No. 3966830 (Patent Document 2) aims to obtain a correct perspective projection image with little distortion in the one-dimensional ray reproduction method. The stereoscopic image display device described in this document has a display device in which a plurality of pixels are arranged in a matrix on a display surface, a plurality of apertures or a plurality of lenses, and controls the direction of light rays from the pixels. A parallax barrier. Here, the display surface of the display device is divided into element images corresponding to each aperture or lens of the parallax barrier. The horizontal pitch of the parallax barrier is an integral multiple of the horizontal pitch of the pixels. An image in which the vertical direction is a perspective projection with a certain viewing distance and the horizontal direction is a parallel projection is divided and arranged for each pixel column.

Japanese Patent Laying-Open No. 2005-077472 Japanese Patent No. 3966830

  By the way, in the case of a method of displaying a stereoscopic image by generating time-division illumination light for the right eye and illumination light for the left eye as described in JP-A-2005-77472 (Patent Document 1), Care should be taken about the diffusion of the emitted light.

  Specifically, while displaying an image for the right eye, illumination light is given only to the right eye of the observer so that the image is not projected to the left eye. If the illumination light is diffused by an optical member such as a display panel from the light source to the viewer's right eye, the light distribution range is widened in addition to the viewer's right eye, which is the desired light distribution range. . At this time, if the diffusion by the optical member is strong, the light distribution range is further widened, so that light rays are projected onto the left eye of the observer. That is, crosstalk occurs in which an image for the right eye is projected onto the left eye. In this case, when the amount of crosstalk is small, a decrease in image quality such as a stereoscopic image appears to be doubled, and when the amount of crosstalk is large, it is difficult for an observer to obtain a parallax image. Become.

  The same applies to the case of the above-mentioned Japanese Patent No. 3966830 (Patent Document 2). When illumination light diffuses in the horizontal direction having parallax, the quality of the stereoscopic image is lowered or stereoscopic viewing becomes difficult.

  However, the higher the directivity of the light beam emitted from the light source, the better the quality of the stereoscopic image is not improved. If the diffusion of the illumination light is excessively suppressed, uneven brightness in the screen due to a light source such as a display device and a backlight is recognized. The image quality deteriorates due to the influence of the luminance unevenness, or the stereoscopic image becomes difficult to observe.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a stereoscopic image display device that displays a stereoscopic image with high resolution and good image quality.

  In summary, the present invention is a stereoscopic image display device, which includes a display panel, a light irradiation unit for backlight, and a directivity mitigation unit. The display panel displays a stereoscopic image having parallax only in the first direction. The light irradiation unit irradiates the display panel with a light beam having directivity. The directivity relaxation unit is provided on the light irradiation unit side or the viewer side opposite to the light irradiation unit with respect to the display panel, and reduces the directivity of the light beam in a second direction different from the first direction.

  Preferably, the second direction is a direction perpendicular to the first direction among the directions along the surface of the display panel.

Preferably, the first direction is a left-right direction with respect to the observer.
Preferably, the light irradiation unit switches the light distribution of the light beams so that the light beams alternately reach the right eye and the left eye of the observer. In this case, the display panel displays the right eye image or the left eye image of the observer in synchronization with switching of the light distribution of the light beam.

  More preferably, when the light irradiation unit distributes light so that light enters the left and right eyes of the observer, the intensity of light incident on the other eye is equal to the intensity of light incident on one eye. 5% or less.

  Preferably, the display panel displays a stereoscopic image according to a light beam reproduction method. In this case, the stereoscopic image display device further includes a light guide member that is provided on the surface on the viewer side of the display panel and has an opening that guides the light beam that has passed through the display panel to the right or left eye of the viewer.

  More preferably, the light guide member is a lenticular lens having a periodic structure in the first direction.

  Preferably, the light irradiation unit is provided between the light source unit including a plurality of light source elements and the display panel and the light source unit, and optically refracts light emitted from the plurality of light source elements in the direction of the display panel. Member.

  More preferably, the optical member is a lenticular lens having a periodic structure in the first direction.

  In a preferred embodiment, the directivity relaxation unit is provided between the observer and the light guide member.

  In another embodiment of the preferred embodiment, the directivity mitigating part is provided between the display panel and the optical member.

  In still another embodiment of the preferred embodiment, the directivity mitigating part is provided between the optical member and the light source part.

  In still another embodiment of the preferred embodiment, the directivity mitigating unit includes a plurality of reflectors that are provided close to each light source element and reflect light having a component in the first direction.

  According to the present invention, the resolution of a stereoscopic image is improved by displaying a stereoscopic image having parallax only in a predetermined direction, such as in the one-dimensional ray reproduction method. Further, the directivity mitigation unit is used to mitigate the directivity of the backlight beam in a direction different from the parallax direction, thereby suppressing the influence of luminance unevenness without degrading the image quality. As a result, a stereoscopic image with high resolution and good image quality can be displayed.

It is a figure which shows the structure of the three-dimensional image display apparatus 101 by Embodiment 1 of this invention. It is a figure which shows the structure of a part of the backlight part 7 of FIG. It is a figure for demonstrating the relationship between the magnitude | size of each cylindrical lens 13a which comprises the lenticular lens 13, and a viewing zone angle. It is a figure for demonstrating the relationship between an element image area | region and a viewing zone angle. It is a figure which shows typically an example of a structure of the directivity relaxation part 31 of FIG. It is a figure which shows intensity distribution of the light in an observer's left-right direction. It is a figure which shows the structure of the three-dimensional image display apparatus 102 by Embodiment 2 of this invention. It is a figure which shows the structure of the three-dimensional image display apparatus 103 by Embodiment 3 of this invention. It is a figure which shows the structure of the three-dimensional image display apparatus 104 by Embodiment 4 of this invention. It is a figure which shows the structure of a part of light source part 5a of FIG. It is a figure which shows the structure of the three-dimensional image display apparatus 105 by Embodiment 5 of this invention. It is the figure which looked at the optical system of the stereo image display apparatus using a light beam reproduction method from the side. It is a perspective view of the optical system of the stereoscopic image display apparatus using a light beam reproduction method. It is a figure which shows the viewing zone angle of the light which passes through one lens. It is a figure which shows a visual field.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Embodiment 1]
(Configuration of stereoscopic image display device)
FIG. 1 is a diagram showing a configuration of a stereoscopic image display apparatus 101 according to Embodiment 1 of the present invention.

  With reference to FIG. 1, a stereoscopic image display apparatus 101 is a one-dimensional ray reproduction type stereoscopic image display apparatus. Furthermore, the stereoscopic image display apparatus 101 can display a right-eye image and a left-eye image in a time-sharing manner in order to display a high-resolution stereoscopic image. As illustrated in FIG. 1, the stereoscopic image display apparatus 101 includes a stereoscopic display unit 3, an image control unit 4, a backlight unit 7, a light source control unit 8, a camera 9, a pupil position detection unit 26, and a directivity. And the sex relaxation part 31.

  Here, in FIG. 1, the stereoscopic display unit 3 is arranged along the XY plane, and the thickness direction of the stereoscopic display unit 3 is defined as the Z direction. For the observer of the stereoscopic display unit 3, the left-right direction (horizontal direction) is the Y direction, and the up-down direction (vertical direction) is the X direction. The setting of the coordinate axes in the other figures is the same.

  The stereoscopic display unit 3 displays a light reproduction type stereoscopic image. The stereoscopic display unit 3 includes a stereoscopic lens array 1 and a display panel 2. In the case of Embodiment 1, the stereoscopic lens array 1 is a lenticular lens having a periodic structure in the left-right direction (Y direction). In the case of a lenticular lens, motion parallax occurs in the left-right direction (Y direction) but does not occur in the up-down direction (X direction). However, since the vertical motion parallax is not so required, it is considered that there is no significant effect on stereoscopic vision.

  The display panel 2 is a transmissive panel for displaying an image. In the case of Embodiment 1, the image displayed on the display panel 2 is a stereoscopic image having parallax only in the left-right direction (Y direction). The display panel 2 includes a plurality of pixels, and displays an image by controlling transmission of backlight light from the backlight unit 7 in units of pixels. As the display panel 2, for example, a liquid crystal panel can be used.

  The image control unit 4 controls the display image on the display panel 2 to display an image on the display panel 2. More specifically, the image control unit 4 determines the operation of each pixel of the display panel 2, more specifically, the light transmission state by each pixel.

  The backlight unit 7 irradiates the display panel 2 with backlight irradiation light as a light irradiation unit. The backlight unit 7 includes a light source unit 5 and a light distribution lens array 6, and is disposed on the back side of the display panel 2 as viewed from the observer. Hereinafter, a specific configuration of the backlight unit 7 will be described with reference to FIG.

  FIG. 2 is a diagram showing a partial configuration of the backlight unit 7 of FIG. 2A is a side view of a part of the backlight unit 7 of FIG. 1, and FIG. 2B is a perspective view.

  As shown in FIGS. 2A and 2B, the light source unit 5 constituting the backlight unit 7 includes a plurality of linear light sources 20 as light source elements. Each linear light source 20 is configured by combining an LED (Light-Emitting Diode) 21 that is a semiconductor light source and a light guide path 22 that receives light from the LED 21. 1 is a lenticular lens 23 having a periodic structure in the Y direction. Each linear light source 20 is disposed in parallel with the direction of the main axis (X direction) of the lenticular lens 23.

  Here, a mechanism for realizing light distribution will be described. Hereinafter, the plurality of linear light sources 20 corresponding to the cylindrical lens 23a which is one lens part constituting the lenticular lens 23 is referred to as one block.

  The light incident on the surface (incident surface) of the cylindrical lens 23a on the light source unit 5 side has an incident angle and an incident position on the incident surface of the light and an exit angle corresponding to the lens shape, and the surface on the observer side of the lens 23a ( The light exits from the exit surface. Therefore, light emitted from each linear light source 20 in one block and incident on the corresponding lens 23a is emitted from the lens 23a at an angle determined by the positional relationship between each linear light source 20 and the lens 23a and the shape of the lens 23a. From another viewpoint, each linear light source 20 included in one block is arranged so that light emitted from each linear light source 20 travels at a different angle after passing through the lens.

  Therefore, the backlight unit 7 can distribute light in a predetermined direction depending on the position of the linear light source 20 that is turned on for each block. For example, when the rightmost linear light source 20a in one block in FIG. 2 is turned on, light is emitted at an angle of θ1 with respect to the optical axis (Z direction) of the lens 23a. The value of θ1 is determined by the positional relationship between the lens 23a and the linear light source 20a. When the seventh linear light source 20b from the right end in one block is turned on, light is emitted at an angle of θ2 with respect to the optical axis of the lens 23a.

  Since the light distribution control by the backlight unit 7 is performed as described above, it is preferable that the linear light source 20 as the light source element is disposed at the focal length of the lenticular lens 23. At this time, the light beams emitted from the respective blocks of the light source unit 5 and transmitted through the lenticular lens 23 are substantially parallel, so that the lenticular lens 23 emits light having very high directivity. Therefore, the stereoscopic image display apparatus 101 according to the first embodiment can distribute light to a narrow range, for example, the position of the observer's right eye or left eye.

  Referring to FIG. 1 again, the light source control unit 8 controls lighting of the light source element (the linear light source 20 in FIG. 2) of the backlight unit 7 according to a desired emission angle. The relationship between the emission angle and the light source element to be lit is determined in advance by the design of the backlight unit 7, and the light source control unit 8 determines the light source element to be lit based on this relationship. The light source control unit 8 controls the lighting of each light source element so that light emitted from each light source element passes through the light distribution lens array 6 and is guided in a predetermined direction.

  The camera 9 captures an image of an area including the observer. The camera 9 is used as a sensor for detecting the pupil position of the observer who should distribute the light.

  The pupil position detection unit 26 detects the pupil position of the observer by performing image processing on an image captured by the camera 9. For example, the pupil position detection unit 26 detects the observer's pupil position based on a light / dark pattern in the image.

  Based on the information from the pupil position detection unit 26, the light source control unit 8 described above emits light from each block of the light source unit 5 of the backlight unit 7 so as to distribute light toward a position near the observer's pupil. Control the output. The image control unit 4 appropriately controls the display position of the element image based on information from the pupil position detection unit 26.

  The directivity alleviating unit 31 is disposed in parallel with the display panel 2 between the observer and the stereoscopic lens array 1. The directivity relaxation unit 31 is a plate-like optical member that scatters light rays so that the directivity in the vertical direction (X direction) is relaxed. Since the direction of the parallax of the stereoscopic image is the left-right direction, the image quality of the stereoscopic image is not affected even if the directivity of light rays is relaxed in the vertical direction. As a result, the directivity alleviating unit 31 can reduce luminance unevenness by reducing the directivity of the light beam from the backlight unit 7 without affecting the image quality of the stereoscopic image. A specific configuration example of the directivity relaxation unit 31 will be described later with reference to FIG.

(Expansion of viewing zone in stereoscopic image display device)
The stereoscopic image display apparatus 101 according to Embodiment 1 overcomes the compatibility between resolution and viewing zone, which is a problem of the light reproduction type, and has a wide area (viewing zone) where a stereoscopic image can be observed compared to the conventional one, and is high. A stereoscopic image with resolution can be generated. This will be described below.

  In the first embodiment, the lenticular lens 13 having a large number of lenses is used to ensure the resolution of the stereoscopic image. In this case, a method of compensating for the viewing zone that decreases as the number of lenses increases by controlling the image displayed on the display panel 2 is used. This method will be described with reference to FIGS.

  FIG. 3 is a diagram for explaining the relationship between the size of each cylindrical lens 13a constituting the lenticular lens 13 and the viewing zone angle. Referring to FIG. 3, an element image region 15a for displaying an element image is determined in accordance with the size of one cylindrical lens 13a constituting the lenticular lens 13. In the case of the viewing zone angle 16a shown in FIG. 3, the display image can be observed at the observer position a, but the display image cannot be observed at the observer position b or the observer position c.

  Therefore, in order to enable the display image to be observed at the observer position b and the observer position c, a method of expanding the element image area to the area 15 in FIG. 3 by enlarging the size of each cylindrical lens 13a is conceivable. . However, as described above, when the individual lenses 13a are enlarged, the total number of lenses is reduced, so that the resolution of the stereoscopic image is lowered. In response to this problem, the stereoscopic image display apparatus 101 according to the first embodiment changes the element image area according to the position of the observer as shown in FIG. 4 while keeping the size of each cylindrical lens 13a as it is.

  FIG. 4 is a diagram for explaining the relationship between the element image region and the viewing zone angle. Referring to FIG. 4, in order to enable the observer to observe the display image even at observer positions b and c, the element image area is set within the area 15 as shown in FIG. Change it. That is, when the observer is at the observer position a, the element image is displayed in the area Ra, when the observer is at the observer position b, the element image is displayed in the area Rb, and when the observer is at the observer position c. The element image is displayed in the region Rc. In this way, the viewing zone can be enlarged by changing the region for displaying the element image according to the position of the observer without fixing.

  Specifically, in the stereoscopic image display device 101, the image control unit 4 controls the element image displayed on the display panel 2 based on the detection result of the pupil position detection unit 26. The light source control unit 8 controls the light distribution of the backlight unit 7 so that the element image is projected onto a region including the observer's pupil.

(Mechanism of stereoscopic viewing in stereoscopic image display device)
3 and 4 show the case where the viewing zone angle covers both eyes of the observer at the observation position. In order to further improve the resolution of the three-dimensional image, the viewing angle is reduced to one eye of the observer. It is effective to narrow the viewing zone angle.

  In this case, it is not possible to view stereoscopically only by changing the display area of the element image according to the position of the observer, and a mechanism for realizing image separation for the left and right eyes, that is, while displaying an image for one eye A mechanism that prevents the image from being projected onto the other eye is necessary. This is because, in the ray reconstruction method, if the viewing zone angle covers both eyes of the observer, binocular parallax can be obtained because the rays seen by the right and left eyes are different. When the area angle covers only one eye of the observer, the display image is an image for projecting to one eye, and binocular parallax cannot be obtained even if this is projected to the other eye Because.

  In the case of the light beam reproduction method, it is difficult to perform image separation for the left and right eyes with a parallax barrier or a lenticular lens such as a two-lens type, and a method of performing image separation for the left and right eyes in a time division manner is preferable. This method is also adopted in the stereoscopic image display apparatus 101.

  Hereinafter, with reference to FIG. 1, a mechanism capable of stereoscopic viewing by the stereoscopic image display apparatus 101 will be described in more detail. The stereoscopic display unit 3 that is a light-reproducing panel is designed so that the viewing zone angle is narrowed down to one eye of the observer in order to improve the resolution of the stereoscopic image. In the case of Embodiment 1, the image displayed on the display panel 2 is a stereoscopic image having parallax only in the left-right direction (horizontal direction).

  Specifically, the stereoscopic image display apparatus 101 performs image separation for the left and right eyes in a time-sharing manner so that the image is not projected to the other eye while displaying the image for one eye. That is, the image control unit 4 displays the right eye image and the left eye image alternately so that the right eye image is displayed in a certain period and the left eye image is displayed in the next period. To display. Further, the image control unit 4 changes the display area of the element image based on the information from the pupil position detection unit 26 according to the position of the observer's pupil.

  The light source control unit 8 controls the backlight unit 7 and distributes the backlight to the right eye of the observer based on information from the pupil position detection unit 26 during the right-eye image display period. In the left-eye image display period, a backlight is distributed to the left eye of the observer based on information from the pupil position detection unit 26. That is, the light source control unit 8 performs light distribution control that follows the positions of the left eye and the right eye for the left eye image and the right eye image, respectively.

  As described above, according to the stereoscopic image display apparatus 101, the time-division display of the left and right images and the light distribution control of the backlight are cooperatively executed, so that the image for one eye is displayed on the other eye. The image can be prevented from being projected. Through these series of coordinated controls, the observer can perceive a light reproduction type high-resolution stereoscopic display image over a wide viewing area. That is, it is possible to achieve both the resolution of the stereoscopic image and the expansion of the viewing area in the stereoscopic image display device.

(Configuration and effect of directivity mitigation unit)
FIG. 5 is a diagram schematically illustrating an example of the configuration of the directivity relaxation unit 31 in FIG. 1. 5A is a perspective view of the directivity alleviating unit 31, FIG. 5B is a side view seen from the Y direction, and FIG. 5C is a side view seen from the X direction.

  With reference to FIGS. 1 and 5, the directivity alleviating portion 31 is a plate-like translucent member disposed in parallel with the display panel 2 (that is, along the XY plane). The directivity relaxation part 31 can be formed using glass etc., for example.

  On the surface 31a on the viewer side (+ Z direction side) of the directivity relaxation portion 31, a plurality of grooves having a wedge-shaped cross section and extending in the Y direction are formed. That is, as shown in FIG. 5B, a plurality of V-shaped grooves are continuous in the X direction on the surface 31a of the directivity alleviating portion 31 viewed from the Y direction. On the other hand, as shown in FIG. 5C, the shape of the surface 31a of the directivity alleviating portion 31 viewed from the X direction is uniform.

  Accordingly, the light beam 33 emitted from the backlight unit 7 and transmitted through the display panel 2 is scattered at a wide angle in the X direction (vertical direction) on the surface 31a of the directivity alleviating unit 31, but is scattered in the Y direction (horizontal direction). Is hardly scattered. In the case of the first embodiment, a stereoscopic image having a parallax is displayed on the display panel 2 only in the left-right direction (Y direction). However, since the directivity of the light beam in the Y direction is maintained, A high-quality stereoscopic image can be observed by the parallax of the image projected on the screen.

  On the other hand, since the directivity of the light beam is relaxed in the X direction by passing through the directivity alleviating unit 31, the luminance unevenness in the X direction of the linear light source of the backlight unit 7 is made uniform. Thereby, the image quality of the display image can be further improved.

  In addition, the shape of the directivity relaxation part 31 shown in FIG. 5 is an example. Any shape can be used as long as the optical member scatters light so that the directivity of light in a direction different from the left-right direction (Y direction), which is the direction of parallax, is preferably relaxed. Good.

  Next, experimental results on the relationship between the diffusion of light in the left-right direction and stereoscopic vision will be described. The stereoscopic image display apparatus used in the experiment is the same as that described in FIG. However, in place of the directivity mitigating portion 31 of FIG. 1, two types of isotropic diffusion members of a large diffusion and a small diffusion are provided. In this case, the light beam is equally diffused in the vertical direction and the horizontal direction by the isotropic diffusion member.

  In the experiment, it was assumed that there was an observer at a distance of 500 mm from the stereoscopic display unit 3, and directional light was distributed from the backlight unit 7 to the right eye and the left eye. And the intensity distribution of the light of the left-right direction in the distance of 500 mm from the three-dimensional display part 3 in this case was measured.

  FIG. 6 is a diagram illustrating the light intensity distribution in the left-right direction (horizontal direction) of the observer. FIG. 6A is a diagram of light intensity distribution when a diffusion member with small diffusion is used, and FIG. 6B is a diagram of light intensity distribution when a diffusion member with large diffusion is used. FIGS. 6A and 6B show both a light intensity distribution curve RE when light is distributed to the right eye and a light intensity distribution curve LE when light is distributed to the left eye. The vertical axis represents the light intensity normalized by 1 with the maximum value. The horizontal axis indicates the position in the left-right direction (horizontal direction). In this case, the center position of both eyes is 0, the position on the right eye side is expressed as negative, and the position on the left eye side is expressed as positive. The distance between both eyes is 65 mm.

  As shown in FIG. 6A, when the diffusion of the diffusing member is small, it can be seen that the intensity of light entering the right eye when the left-eye illumination is performed is about 5%. When a stereoscopic image is displayed on the stereoscopic display unit 3 in this state and stereoscopically viewed, a so-called crosstalk that occurs because the stereoscopic image directed to one eye is also irradiated to the other eye, such as a double image. Almost no image was generated, and a good stereoscopic image was observed.

  On the other hand, as shown in FIG. 6B, it can be seen that when the diffusion of the diffusing member is large, the intensity of light entering the right eye when the left-eye illumination is performed is about 25%. In this state, when a stereoscopic image is displayed on the stereoscopic display unit 3 and stereoscopically viewed, a crosstalk image such as a double image is observed.

  From the above experimental results, when the light is distributed by the backlight unit 7 so that the light beam is incident on one of the left and right eyes of the observer, the intensity of the light beam incident on the other eye is the light beam incident on one eye. It is desirable that the strength is 5% or less.

[Embodiment 2]
The arrangement position of the directivity relaxation unit 31 may be a position different from that of the first embodiment.

  FIG. 7 is a diagram showing a configuration of the stereoscopic image display apparatus 102 according to the second embodiment of the present invention. The stereoscopic image display apparatus 102 in FIG. 7 is different from the stereoscopic image display apparatus 101 in FIG. 1 in that the directivity relaxation unit 31 is disposed between the stereoscopic display unit 3 and the light distribution lens array 6. Since the stereoscopic image display apparatus 102 in FIG. 7 is the same as the stereoscopic image display apparatus 101 in FIG. 1 in other respects, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  As shown in FIG. 7, even if the directivity alleviating unit 31 is disposed between the stereoscopic display unit 3 and the light distribution lens array 6, the first embodiment applies to the light emitted from the backlight unit 7. The same directivity mitigation effect as in the case of can be obtained. In the case of FIG. 7, the light beam that has passed through the directivity mitigating unit 31 illuminates the stereoscopic display unit 3, thereby projecting an image to the observer.

  In particular, in the case of FIG. 7, since the shape corresponding to the directivity mitigating portion 31 can be formed on the surface of the light distribution lens array 6 on the viewer side (+ Z direction), the light distribution lens array 6, the directivity mitigating portion 31, and the like. Is advantageous in that it can be manufactured integrally. As a result, since it is not necessary to provide the directivity mitigating unit 31 independently, reduction in the number of members, improvement in assembling property, simplification of parts management, and cost reduction can be expected.

[Embodiment 3]
FIG. 8 is a diagram showing the configuration of the stereoscopic image display apparatus 103 according to the third embodiment of the present invention. FIG. 8 shows another example of the arrangement position of the directivity relaxation unit 31. That is, the stereoscopic image display device 103 of FIG. 8 is the stereoscopic image display device 101 of FIGS. 1 and 7 in that the directivity relaxation unit 31 is disposed between the light distribution lens array 6 and the light source unit 5. , 102. In other respects, the stereoscopic image display device 103 in FIG. 8 is the same as the stereoscopic image display devices 101 and 102 in FIGS. 1 and 7, and therefore, the same or corresponding parts are denoted by the same reference numerals. Do not repeat.

  Even if the directivity alleviating unit 31 is arranged at the position of FIG. 8, the same directivity alleviating effect as in the first embodiment can be obtained. In this case, the light beam emitted from the light source unit 5 is diffused in the X direction by the directivity mitigating unit 31, and then passes through the light distribution lens array 6 to give directivity in the Y direction. Then, the stereoscopic display unit 3 is illuminated with the light beam having directivity in the Y direction, whereby an image is projected to the observer.

  If the directivity reducing unit 31 cannot be disposed at the position of FIG. 7 because the space between the stereoscopic display unit 3 and the light distribution lens array 6 is small, it is disposed at the position of FIG. May be.

[Embodiment 4]
FIG. 9 is a diagram showing a configuration of a stereoscopic image display apparatus 104 according to Embodiment 4 of the present invention. The stereoscopic image display device 104 in FIG. 9 is different from the light source unit 5 in the first to third embodiments in the configuration of the light source unit 5a included in the backlight unit 7 as described later with reference to FIG. As a result, in the case of the stereoscopic image display device 104, the diffusion in the Y direction of the light beam emitted from the LED 21 that is a semiconductor light source constituting the light source unit 5a is limited in advance. Also by this method, the same effect as the directivity alleviating unit 31 of the first to third embodiments can be obtained. Other than that, stereoscopic image display device 104 in FIG. 9 is the same as stereoscopic image display device 101 in FIG. 1, and therefore, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 10 is a diagram showing a partial configuration of the light source unit 5a of FIG. Referring to FIG. 10, light source unit 5 a includes a plurality of linear light sources 20 arranged in parallel with the X direction. Each linear light source 20 includes an LED 21 that is a semiconductor light source, a light guide path 22 that receives light from the LED 21, and a mirror portion 32 that covers a surface of the light guide path 22 excluding the emission direction. The mirror unit 32 substantially totally reflects light rays traveling in directions other than the light exiting direction of the light guide path 22 (for example, the + Y direction, the −Y direction, and the −Z direction).

  By providing the mirror portion 32, the light beam that has passed through the light guide path 22 has directivity in the left-right direction (Y direction) that is the parallax direction, and is approximately in the direction indicated by the dotted line in FIG. Emitted. The emitted light is refracted in the direction of the stereoscopic display unit 3 by the light distribution lens array 6 while maintaining the directivity in the Y direction. On the other hand, the light beam that has passed through the light guide path 22 has little directivity in the X direction. For this reason, the light beam emitted from the linear light source 20 is a light beam that is uniform in the X direction and has little unevenness. As a result, a high-quality stereoscopic image is projected to the observer.

  As described above, the mirror unit 32 in FIG. 10 functions as a reflecting plate that reflects the light having the Y-direction component among the light beams emitted from the LED 21, and corresponds to the directivity mitigating unit 31 in the first to third embodiments. . In the case of the stereoscopic image display device 104 of FIG. 10 as well, in the same way as in the case of the second embodiment, it is not necessary to provide the directivity alleviating unit 31 independently, so that the number of members is reduced, the assemblability is improved, and the parts management Simplification and cost reduction can be expected.

[Embodiment 5]
In the first to fourth embodiments, the three-dimensional image reproduction method has been described as the light beam reproduction method, but the directivity relaxation unit 31 can also be used in other methods. Here, the binocular stereoscopic image display device 105 will be described.

  The principle of binocular stereoscopic vision is that images for the left eye and right eye are displayed on the left and right eyes of the observer, respectively. The stereoscopic image display apparatus 105 according to Embodiment 5 displays the right-eye image and the left-eye image in a time-sharing manner, and controls the light distribution of the backlight to the right eye and the left eye in synchronization therewith.

  FIG. 11 is a diagram showing a configuration of a stereoscopic image display apparatus 105 according to Embodiment 5 of the present invention. The stereoscopic image display device 105 in FIG. 11 is obtained by omitting the stereoscopic lens array 1 from the stereoscopic image display device 105 in the first embodiment shown in FIG. According to the binocular stereoscopic image display device 105 having this configuration, the left and right images are displayed on the display panel 2 in a time division manner, and the backlight unit is based on the position of the observer's pupil detected by the pupil position detection unit 26. 7, the left and right images can be separated by distributing light to the left and right eyes in synchronization with the images. Therefore, according to the stereoscopic image display device 105, a binocular stereoscopic display can be realized.

  Conventionally, the left and right images are spatially separated by a parallax barrier or lenticular lens. In this method, since the right-eye image and the left-eye image are displayed at the same time, the number of pixels of each image is half the number of pixels of the display panel, and therefore the display resolution of the stereoscopic image is also half of the display resolution of the display panel. descend.

  As another conventional method for maintaining the resolution, the left and right images are displayed in a time-sharing manner, and the left and right images are separated by the observer using glasses with left and right eye shutters synchronized with the display of the left and right images. There was a thing. However, this method requires the observer to wear glasses, and the structure of the glasses tends to be complicated, which places a burden on the observer.

  According to the stereoscopic image display device 105 according to the fifth embodiment, the right-eye and left-eye images are displayed in a time-sharing manner, so that the number of pixels on the display panel can be maintained, and the observer wears glasses or the like. There is no need to do. Therefore, the observer can observe a high-resolution stereoscopic image without glasses. At this time, the observer can observe a stereoscopic image with higher resolution and higher quality than before due to the effect of the directivity relaxation unit 31.

  In addition, the arrangement | positioning position of the directivity relaxation part 31 can also be arrange | positioned in the position which was demonstrated in Embodiment 2-4.

[Other variations]
In each of the above embodiments, when the position where the observer observes the stereoscopic image is designated in advance, the device configuration of the stereoscopic image display device can be simplified. In this case, the backlight unit 7 is designed so that light is distributed to the right and left eyes of the observer at the designated position, and an image at the designated position is also displayed on the display panel 2. Thereby, the camera 9 and the pupil position detection unit 26 can be omitted.

  Moreover, in each above embodiment, the example which used LED which is a semiconductor light-emitting device as a light source was shown. Since the LED is small compared to a cold cathode tube (CCFL) often used as a backlight of a liquid crystal panel, it is easy to mount the LED. In addition, since the response speed is high, it is possible to cope with time-division lighting control. Furthermore, the drive circuit can be easily realized. From these reasons, it is preferable to use an LED. However, the light source element in the present invention is not limited to the LED.

  In the first to fourth embodiments described above, the stereoscopic lens array 1 (lenticular lens) is used as a constituent member of the stereoscopic display unit 3. It is possible to display a stereoscopic image by. Therefore, any light guide member having an opening that guides the light beam transmitted through the display panel 2 to the right or left eye of the observer can be used instead of the stereoscopic lens array 1. The stereoscopic lens array 1 is described in Embodiments 1 to 4 as a preferable example of the light guide member having such an opening.

  In the first to fifth embodiments, the light distribution lens array 6 (lenticular lens) is used as a constituent member of the backlight unit 7, but the present invention is not limited to this. Any optical member that refracts the light emitted from the light source unit 5 in the direction of the display panel 2 can be used instead of the light distribution lens array 6. The light distribution lens array 6 is described in the first to fifth embodiments as a preferred example of an optical member that refracts such light rays.

  The embodiment disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Stereoscopic lens array, 2 Display panel, 3 Stereo display part, 4 Image control part, 5, 5a Light source part, 6 Light distribution lens array, 7 Backlight part, 8 Light source control part, 9 Camera, 13 Lenticular lens 15, 15a Element image area, 20 linear light source, 21 LED, 22 light guide, 23 lenticular lens, 26 pupil position detection unit, 31 directivity mitigation unit, 32 mirror unit, 101-105 stereoscopic image display device.

Claims (13)

A display panel for displaying a stereoscopic image having parallax only in the first direction;
A light irradiation unit for a backlight that irradiates the display panel with light having directivity; and
Directivity relaxation that is provided on the light irradiation unit side or the viewer side opposite to the light irradiation unit with respect to the display panel, and reduces the directivity of the light beam in a second direction different from the first direction. A stereoscopic image display device.   The stereoscopic image display device according to claim 1, wherein the second direction is a direction perpendicular to the first direction among the directions along the surface of the display panel.   The stereoscopic image display device according to claim 1, wherein the first direction is a left-right direction with respect to the observer. The light irradiation unit switches the light distribution of the light beam so that the light beam alternately reaches the right eye and the left eye of the observer,
The stereoscopic image display device according to claim 3, wherein the display panel displays an image for the right eye or the left eye of the observer in synchronization with switching of the light distribution of the light beam.   When the light irradiation unit distributes light so that the light beam is incident on one of the left and right eyes of the observer, the intensity of the light beam incident on the other eye is the intensity of the light beam incident on the one eye. The stereoscopic image display device according to claim 4, wherein the stereoscopic image display device has a strength of 5% or less. The display panel displays a stereoscopic image according to a light beam reproduction method,
The stereoscopic image display apparatus is further provided with a light guide member provided on a surface of the display panel on the viewer side, and having an opening that guides the light beam transmitted through the display panel to the right eye or the left eye of the viewer. The stereoscopic image display device according to claim 4, comprising:   The stereoscopic image display device according to claim 6, wherein the light guide member is a lenticular lens having a periodic structure in the first direction.   The stereoscopic image display device according to claim 6, wherein the directivity relaxation unit is provided between the observer and the light guide member. The light irradiator is
A light source unit including a plurality of light source elements;
The optical member which is provided between the said display panel and the said light source part, and refracts the light radiate | emitted from these light source elements in the direction of the said display panel is given in any one of Claims 1-7. The stereoscopic image display device described.   The stereoscopic image display device according to claim 9, wherein the optical member is a lenticular lens having a periodic structure in the first direction.   The stereoscopic image display device according to claim 9, wherein the directivity relaxation unit is provided between the display panel and the optical member.   The stereoscopic image display device according to claim 9 or 10, wherein the directivity relaxation unit is provided between the optical member and the light source unit.   The stereoscopic image display device according to claim 9 or 10, wherein the directivity relaxation unit includes a plurality of reflection plates that are provided in proximity to each of the light source elements and reflect light having a component in the first direction.

Images