JP3585781B2 - 3D display device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a stereoscopic display device.
[0002]
[Prior art]
2. Description of the Related Art A conventional stereoscopic display device generally uses a binocular system that presents images (hereinafter, parallax images) from respective viewpoints to left and right eyes of an observer. As a method of presenting each parallax image to the left and right eyes of the observer, there are roughly two methods, a method using glasses and a method without glasses.
[0003]
As a method of using the glasses, for example, there are two methods, that is, a method of using shutter glasses and a method of controlling the polarization direction of display and using polarized glasses.
[0004]
In the method using shutter glasses, left and right parallax images are alternately displayed on a display device. On the other hand, the spectacles worn by the observer are provided with an optical shutter for controlling the transmission and non-transmission of light of the left and right eyes. The optical shutter is driven in synchronization with the display so that the parallax images reach the left and right eyes of the observer.
[0005]
In the method of controlling the polarization direction of display and using polarized glasses, an element for switching the polarization direction of light is provided on the front surface of the display device, while the observer uses polarized glasses. A switching element installed on the front of the display device switches the polarization direction of the display between 0 degree and 90 degrees. The display device displays the left and right parallax images alternately in time, similarly to the method of the shutter glasses. A display having a specific polarization direction is performed by driving a switching element arranged in front of the display device in synchronization with the display. Since the observer wears polarizing glasses equipped with polarizing plates having left and right polarization directions of 0 and 90 degrees, the left and right parallax images can be seen by each eye.
[0006]
As a method without using glasses, there is a method using a lenticular lens or a parallax barrier. In this method, the display device displays parallax images for left and right for each vertical pixel line. A lenticular lens or a parallax barrier is provided on the front surface of the display device so that light emitted from each pixel line is guided to the left and right eyes of the observer.
[0007]
[Problems to be solved by the invention]
As described above, stereoscopic display devices are roughly classified into a system using glasses and a system without glasses. In the method using glasses, the observer must wear glasses in order to present a stereoscopic display to the observer, which causes discomfort and inconvenience to the observer due to wearing the glasses.
[0008]
Further, in the method that does not use the glasses, since it is necessary to display the left and right parallax images for each vertical pixel line of the display device, the number of pixels in one row of the display device is shared for right and left, and the image is halved. The result is an image with the number of pixels.
[0009]
Therefore, an object of the present invention is to provide a stereoscopic display device that realizes display of a stereoscopic image having the same number of pixels as the display device without using glasses.
[0010]
[Means for Solving the Problems]
In view of the above problems, according to the present invention, a first wedge-shaped light guide and a second wedge-shaped light guide are formed such that the thickness on a first side is greater than the thickness on a second side opposed to the first side. A light guide formed by overlapping the first side of the first wedge-shaped light guide with the second side of the second light guide, and a first side of the first wedge-shaped light guide A first light source provided on the light guide, a second light source provided on a first side of the second wedge-shaped light guide, and the first light source installed on the light guide and emitted from the light guide And a prism film that converts the light of the second light source into angles corresponding to the first and second parallaxes, a transmissive display panel on the prism film, and synchronization with the first light source and the second light source. And a synchronous driving means for displaying the first and second parallax images on the display panel. The first light source is turned on in synchronization with the display on the display panel, and the second light source is turned on in synchronization with the display of the second parallax image on the display panel. And a display device for displaying a second parallax image on the display panel in a time-division manner.
[0011]
Further, a plane parallel to the first side of the first wedge-shaped light guide and perpendicular to the display surface of the display panel is a symmetrical plane, and the light of the first light source and the light of the second light source is at an angle corresponding to parallax. The three-dimensional display device according to claim 1, wherein the light is emitted from a panel.
[0012]
2. The vertex angle of the prism provided on the prism film is symmetrically distributed on a display panel center line parallel to a first side of the first wedge-shaped light guide. 3. 3D display device is provided.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
(Example 1)
FIG. 1 shows a basic configuration of the present invention.
[0014]
The wedge-shaped light guides 101 and 102 are overlapped to form a light guide 1, and light sources 2 a and 2 b are installed on the left and right sides of the light guide 1. In the present embodiment, for convenience, the light source 2a side in FIG. 1 is described as a left side or simply left side as viewed from the screen, and the light source 2b side as a right side or simply right side as viewed from the screen, but the left and right sides are not limited.
[0015]
Between the two superposed wedge-shaped light guides 101 and 102, a layer having a lower refractive index than the wedge-shaped light guides 101 and 102, such as an air layer, is interposed. Here, the wedge-shaped light guides 101 and 102 alone have an angular distribution of emitted light having relatively high directivity.
[0016]
FIG. 2 shows an emission light distribution of the light guide 1 configured as described above. Here, the emitted light angle distributions when the left light source 2a is turned on and when the right light source 2b is turned on are shown. The horizontal axis indicates the angle from the normal direction of the light emitting surface of the light guide 1, and the normal direction is 0 degree. The left side is displayed as positive and the right side is displayed as negative.
[0017]
The light from the left light source 2a travels inside the light guide 102 and is emitted rightward from the front, and the emitted light has the maximum intensity near -70 degrees. On the other hand, the light from the right light source 2b travels in the light guide 101 and is emitted leftward from the front, and the emitted light has the maximum intensity near +70 degrees. As described above, the angle at which the intensity of the emitted light is maximum is the same angle on both the positive and negative sides. The angle at which the intensity of the emitted light becomes maximum depends on the taper angles of the wedge-shaped light guides 101 and 102, the refractive indexes of the two wedge-shaped light guides 101 and 102, and the like. For example, in the case of polymethyl methacrylate or polycarbonate, which is an optical material used as a light guide material, the angle is usually from about 60 degrees to about 80 degrees.
[0018]
Assuming that the distance between the left and right eyes 3 and 4 of the observer is about 65 mm and the viewing distance from the liquid crystal panel 5 to the observer is about 300 mm, a straight line connecting the center of the liquid crystal panel 5 to the right eye 4 or the left eye 3 and the liquid crystal panel 5 Is about 6 degrees. Therefore, a prism film 6 for converting the 70 ° outgoing light peak angle shown in FIG. 2 to about 6 ° is required.
[0019]
The prism film 6 has a prism formed in a direction parallel to the light source, and is set on the light guide 1 so that the prism surface faces the light guide 1 side. Thereby, an emission light distribution as shown in FIG. 3 is obtained.
[0020]
An example of a design method of the prism film 6 will be described below.
[0021]
FIG. 4 shows a process in which light emitted from the light guide 1 passes through the prism film 6 and enters the left eye 3. The angle at which the intensity of light emitted from the light guide 1 is maximum is φ, the angle of the apex angle of the prism film on the incident surface side of light from the light guide 1 is a1, the reflection surface side is a2, and the refractive index of the prism film Is n. For light emitted from the light guide 1 and incident on the prism film 6 from the incident surface of the prism film 6, the angle x between the normal direction of the incident surface and the traveling direction of the incident light is:
x = arcsin ((sin (φ + a1−π / 2)) / n) (1)
It is expressed as Further, the angle y between the light reflected by the reflecting surface of the prism film 6 and reaching the exit surface of the prism film 6 and the normal direction of the exit surface of the prism film 6 is:
y = 3 × a2-π / 2-x (2)
It is expressed as Therefore, the angle θ emitted from the exit surface of the prism film 6 is
θ = arcsin (n × sin (y)) (3)
It is expressed as In the present embodiment, when φ = 70 degrees, the refractive index of the prism film 6 is, for example, n = 1.57, and the angle of the apex angle is, for example, a1 = a2 = 34.5 degrees, the prism film 6 Can be set to θ = 6.8 degrees. The same applies to the case of the right eye 4 because the angle of the apex angle of the prism film 6 is bilaterally symmetric.
[0022]
The light whose output angle has been converted by the prism film 6 having the apex angle determined by the above method enters the liquid crystal panel 5. The light emitted from the liquid crystal panel 5 has an emission angle substantially equal to θ.
[0023]
When the left light source 2a is turned on, the light incident on the right eye 4 is emitted from the prism film 6, so that an image for the right eye is displayed on the liquid crystal panel 5. Conversely, when the right light source 2b is turned on, the light incident on the left eye 3 is emitted from the prism film 6, so that an image for the left eye is displayed. This is performed by synchronizing the lighting of the left and right light sources 2a and 2b and the display of an image on the liquid crystal panel 5 with time by the synchronous driving device 7 in which the left and right light sources 2a and 2b and the liquid crystal panel 5 are connected. , A stereoscopic display can be presented to the observer.
(Example 2)
A second embodiment will be described for a case where the left and right width of the liquid crystal panel 5 is equal to or greater than the distance between the left and right eyes 3 and 4.
[0024]
In such a case, if the vertex angle of the prism film 6 is determined with respect to the center of the screen as in the first embodiment, the observer cannot obtain an accurate three-dimensional image at the left and right ends of the screen. This is because, as shown in FIG. 5, the angle formed by the straight line connecting the left and right ends of the screen to the left and right eyes of the observer with the normal to the display surface is significantly different from the center of the screen. Therefore, it is necessary to change the apex angle of the prism film 6 from the center of the screen to the left and right ends of the screen. An example of a design method of the apex angle of the prism film 6 at this time will be described below.
[0025]
Under the same conditions as above, the distance between the left and right eyes 3 and 4 is about 65 mm, the viewing distance is about 300 mm, and the left and right width of the liquid crystal panel 5 is about 65 mm, which is the same as the distance between the left and right eyes 3 and 4. The angle of the apex angle of 6 may be a1 = a2 = 34.5 degrees.
[0026]
On the other hand, as shown in FIG. 5, at the right end, the angle between the straight line connecting the right eye 4 and the right end of the screen and the normal direction of the liquid crystal panel 5 is 0 degree. On the other hand, the angle between the straight line connecting the left eye 3 and the right end of the screen and the normal direction of the liquid crystal panel 5 is about 12 degrees.
[0027]
FIG. 6 shows a process in which the light emitted from the light guide 1 at this time passes through the prism film 6 and enters the left and right eyes 3 and 4 respectively.
[0028]
Let x, y, and θ shown in Equations (1) through (3) be xr, yr, and θr, respectively, the process of the light beam incident on the right eye 4 and xl, yl, and θl, the process of the light beam incident on the left eye 3. In other words, Equations (1) through (3) can be rewritten as follows.
xr = arcsin ((sin (φ + a2-π / 2)) / n) (4)
yr = 3 × a1-π / 2-xr (5)
θr = arcsin (n × sin (yr)) (6)
xl = arcsin ((sin (φ + a1-π / 2)) / n) (7)
yl = 3 × a2-π / 2-xl (8)
θl = arcsin (n × sin (yl)) (9)
The apex angle of the prism film 6 can be obtained by obtaining a1 and a2 for desired θr and θl from Expressions (4) to (9). In the case of this embodiment, when φ = 70 degrees and n = 1.57, a1 and a2 satisfying θr = 0 degrees and θl = 12 degrees are a1 = 33.5 degrees and a2 = 35.5 degrees, respectively. It becomes.
[0029]
FIG. 7 shows the distribution of the vertex angles a1 and a2 of the prism film 6 when the binocular distance is 65 mm and the distance between the display and the observer is 300 mm. Here, the horizontal axis of the figure indicates the distance to the right from the center of the screen, and the vertical axis indicates the angle of the apex angle of the prism film 6.
[0030]
At the center of the prism film 6, a1 = a2 = 34.3 degrees, which is bilaterally symmetric. As the distance from the center increases, a1 decreases, and conversely, a2 increases. As a result, the individual prisms on the prism film 6 have an isosceles triangular shape symmetrical at the center at the center, but have a distribution in which the apex angle is shifted to the left as going rightward (see FIG. 6).
[0031]
Similarly to the first embodiment, by turning on the left and right light sources 2a and 2b and displaying the left and right parallax images on the liquid crystal screen in synchronization, the observer can see a stereoscopic image without using special glasses.
[0032]
According to the above method, a1 and a2 are obtained for each position where the observer looks at the liquid crystal panel, and the apex angle of the prism film 6 is formed, so that the stereoscopic display can be presented to the observer over the entire liquid crystal panel 5. it can.
[0033]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to provide a stereoscopic display device that realizes display of a stereoscopic image having the same number of pixels as the display device without using glasses.
[Brief description of the drawings]
FIG. 1 is a diagram showing a basic configuration of the present embodiment.
FIG. 2 is a diagram illustrating an angular distribution of light emitted from a wedge-shaped light guide according to the present embodiment.
FIG. 3 is a diagram illustrating an angular distribution of light emitted from a prism film when a prism film is installed on the light guide according to the present embodiment.
FIG. 4 is a diagram showing a light guiding process of light emitted from a light guide in the present example passing through a prism film to the eyes of an observer.
FIG. 5 is a diagram showing directions of light emission from different display positions of the stereoscopic display device to the eyes of the observer in the embodiment.
FIG. 6 is a diagram showing a light guiding process of light emitted from a light guide in the present example passing through a prism film and reaching the eyes of an observer.
FIG. 7 is a diagram illustrating an angle distribution of a vertex angle of a prism film in a direction from a screen center to a screen edge in the present embodiment.
[Explanation of symbols]
1 light guide,
101, 102 Wedge-shaped light guide 2a Left light source 2b Right light source 3 Left eye of observer 4 Right eye of observer 5 Liquid crystal panel 6 Prism film 7 Light source and liquid crystal panel synchronous driving device

Claims (3)

A first wedge-shaped light guide including a first wedge-shaped light guide and a second wedge-shaped light guide each having a thickness on a first side larger than a thickness on a second side opposed to the first side; A light guide formed by overlapping the first side of the body with the second side of the second light guide;
A first light source provided on a first side of the first wedge-shaped light guide;
A second light source provided on a first side of the second wedge-shaped light guide;
A prism film that is installed on the light guide and converts the light of the first light source and the light of the second light source emitted from the light guide into angles corresponding to the first and second parallaxes, respectively ;
A transmissive display panel on the prism film,
Synchronous driving means for displaying first and second parallax images on the display panel in synchronization with the first light source and the second light source,
The first light source is turned on in synchronization with the display of the first parallax image on the display panel, and the second light source is turned on in synchronization with the display of the second parallax image on the display panel. The three-dimensional display device displays the first and second parallax images on the display panel in a time-division manner by turning on the light . With the plane parallel to the first side of the first wedge-shaped light guide and perpendicular to the display surface of the display panel as a plane of symmetry, the light of the first light source and the light of the second light source are separated from the panel at an angle corresponding to parallax. The three-dimensional display device according to claim 1, wherein the light is emitted. 2. The vertex angle of the prism provided on the prism film is symmetrically distributed on a display panel center line parallel to a first side of the first wedge-shaped light guide. 3. 3D display device.

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