Patent Grant
9230462
This application is the National Phase of PCT/JP2008/053916, filed Mar. 5, 2008, which is based upon and claims priority from Japanese Patent Application No. 2007-57898, filed on Mar. 7, 2007, the contents of which are incorporated by reference herein in their entirety.
The present invention relates to an image display device having a plurality of image display elements, and each display surface of the image display elements is directed to an observer to display an image thereon.
In recent years, a stereoscopic display device, which achieves stereo vision by spatially separating a plurality of images with binocular parallax into right and left eyes respectively, by using a lenticular lens, a parallax barrier and the like, is focused on as a stereoscopic display device using a flat-panel display such as a liquid crystal panel. This kind of stereoscopic display device is advantageous in that special glasses are not necessary therefor (for example, Non-patent Document 1).
To generate a stereoscopic image for enhancing effect of the stereoscopic vision, there is disclosed a method of displaying the stereoscopic image by transforming an image, using a perspective projection, toward an oblique direction with respect to a visual axis (Patent Document 1).
Non-patent Document 1: pp 11-21, “three dimensional image engineering” by Takanori Okoshi published by Asakura Publishing, Co. Ltd.
Patent Document 1: U.S. Pat. No. 6,389,236
However, in the image display device in which two or more image display elements are connected to each other, there is a problem that light beams emitted from the display surface of one image display element is reflected on the display surface of the other image display element. Hereinafter, an image of one display surface which is reflected on the other display surface is defined as “a reflection image”.
As described above, the reflection images caused by a reflected light beam emitted from one display surface and reflected on the other display surface accounts for a problem of visibility degradation, and also for the following problem. When an observer recognizes a stereoscopic image, a false stereoscopic image generated by the reflection images on both display surfaces is observed at the same time. That brings discomfort to the observer. Further, even if the display surfaces is simply processed with anti-glare processing for antireflection, scattering light beams caused by the anti-glare processing are reflected diffusely from both the display surfaces, and thereby visibility for the display image degrades.
Therefore, an object of the present invention is to provide an image display device which is capable of preventing an image of one display surface from reflecting on the other display surface.
To achieve the above mentioned object, the image display device according to the present invention for displaying an image on a screen which is a combination of display surfaces of two or more image display-elements comprises:
a polarizing plate arranged on the display surface on condition that extinction takes place between the display surfaces of the image display elements.
The extinction conditions are set such that light entering from the display surface having the polarizing plate attached thereon is transmitted, and light entering from other than the display surface is absorbed, by intersecting polarizing directions of the polarizing plates perpendicularly.
According to the present invention, the polarizing plates arranged on the display surfaces of the image display elements suppress the generation of the reflection image on each display surface, and thereby an observer can be provided with a significantly realistic stereoscopic image not having uncomfortable feeling.
Hereinafter, exemplary embodiments of the invention will be explained with reference to drawings.
The exemplary embodiment of the invention is targeting for an image display device in which two or more image display elements (1, 2) are combined so as to display an image. The exemplary embodiment will be concretely explained taking a case with a combination of the image display elements 1 and 2 as an example. Two image display elements 1 and 2 shown in
When the observer observes the image displayed on the X-axis display surface 1a and the Y-axis display surface 2a with both eyes fixed on the viewpoint 13, the observer observes the right eye image displayed on the X-axis display surface 1a and the Y-axis display surface 2a with the right eye, and observes the left eye image displayed on the X-axis display surface 1a and the Y-axis display surface 2a with the left eye. Therefore, the right eye image and the left eye image displayed on the X-axis display surface 1a and the Y-axis display surface 2a are synthesized, and the observer observes it as one image. In this case, by providing an optical system for stereoscopically displaying such as a lenticular lens, a parallax barrier, a lens array or a pinhole array for integral photography, on the X-axis display surface 1a and the Y-axis display surface 2a, it becomes possible to stereoscopically display the image. Further, in the case of not using the optical system for stereoscopically displaying, the image can be displayed as a two-dimensional image.
As shown in
The extinction condition is set such that light entering from the display surface 1a (or 2a) on which the polarizing plate 30 (or 31) is attached is transmitted and light entering from other than the display surface 1a (or 2a) is absorbed by intersecting the polarizing directions of the polarizing plates 30 and 31 perpendicularly.
According to the exemplary embodiment of the invention, the polarizing plates 30 and 31 are arranged on the display surfaces 1a and 2a of the image display elements 1 and 2 respectively, and the polarizing directions of the polarizing plates 30 and 31 are orthogonal to each other. Therefore, a light beam directed from one display surface 1a (or 2a) to the other display surface 2a (or 1a) is intercepted by the polarizing plate 31 (or 30).
Thus, according to the exemplary embodiment of the invention, the polarizing plates arranged on the display surfaces of the image display elements can suppress reflection of images among the display surfaces, and specifically, when a stereoscopic image is displayed, the observer can be provided with an excellently realistic stereoscopic image without having uncomfortable feeling.
In the above mentioned exemplary embodiment of the invention, the polarizing plates are arranged on the display surfaces of the image display elements basically to suppress reflection of images among the display surfaces. Additionally, another example will be described with reference to
As shown in
The first quarter wavelength plates 5 and 6 in the above are for converting a linear polarization into a circular polarization, and the second quarter wavelength plates 9 and 10 in the above are for converting a circular polarization into a linear polarization. The hollow layers 7 and 8 are formed when a protrusion such as a spacer (unillustrated) is provided between the quarter wavelength plates 5, 6 and 9, 10. The hollow layers 7 and 8 are to maintain an interval between the first quarter wavelength plates 5, 6 and the second quarter wavelength plates 9, 10 so that direction of the circular polarization inverts therein. The polarizing plates 11 and 12 combined with the second quarter wavelength plates 9 and 10 are arranged so that polarization directions of the polarizing plates are orthogonal to each other. The polarizing plates 11 and 12 are processed with an anti-glare processing.
The display surfaces 1a and 2a are rectangle, and contact each other at one side. They are arranged in an elevating direction, that is, in a vertical direction. The display surfaces 1a and 2a of those two image display elements 1 and 2 contact each other at each one side, and thereby the combination of these two display surfaces 1a and 2a forms a screen to display an image. The display surfaces 1a and 2a contact each other at each one side, which means that the display surfaces 1a and 2a are in the closest condition with each other. When the display surfaces 1a and 2a become closer, a stereoscopic angle to view from one surface to the other becomes wider, and an image of one surface is reflected from the other surface more significantly. So, effect of the present invention becomes remarkable. The angle θ between the display surfaces 1a and 2a is 90 degrees in this case; however, the angle is not limited to the above case.
The display surfaces 1a and 2a of the image display elements 1 and 2 are provided with the polarizing plates 3 and 4 respectively, and polarization directions of the polarizing plates 3 and 4 are set to be orthogonal to each other. In an example shown in
In
A light beam (a horizontal polarization) directed from a pixel A of the display surface 1a to the display surface 2a is converted into a right circular polarization 15 by the quarter wavelength plate 5, and then it is converted by the quarter wavelength plate 9 into a vertical polarization 16 which can be transmitted through the polarizing plate 11. The vertical polarization 16 transmitted through the polarizing plate 11 reaches the polarizing plate 12 arranged on a top face of a display surface 2a. In that case, the polarizing plate 12 is arranged so that a polarization direction of polarization transmitted therethrough is orthogonal to one for the polarizing plate 11. Therefore, the vertical polarization 16 can be absorbed. Thus, a light beam emitted from the display surface 1a can be diminished using the polarizing plate 12 on the top face of the display surface 2a, and thereby light reflected from the display surface 2a can be suppressed.
Further, in this structure, outside light 17 (including scattering light caused by the anti-glare processing of the polarizing plates 11 and 12) is transmitted through the polarizing plate 11 and the quarter wavelength plate 9 to become a right circular polarization 18. The right circular polarization 18 is reflected from a surface of the quarter wavelength plate 5 to become a left circular polarization 19, the left circular polarization 19 is transmitted through the quarter wavelength plate 9 to be converted into a horizontal polarization, and then the horizontal polarization is absorbed by the polarizing plate 11.
Furthermore, a light beam (a vertical polarization) directed from a pixel B of the display surface 2a to the display surface 1a is converted into a left circular polarization 20 by the quarter wavelength plate 6, then converted by the quarter wavelength plate 10 into a horizontal polarization 21 which can be transmitted through the polarizing plate 12. The horizontal polarization 21 transmitted through the polarizing plate 12 reaches the polarizing plate 11 arranged on the top face of the display surface 1a. In that case, the polarizing plate 11 is arranged so that a polarization direction of polarization transmitted therethrough is orthogonal to one for the polarizing plate 12. Therefore, the polarizing plate 11 can absorb the horizontal polarization 21. Thus, light emitted from the display surface 2a is diminished using the polarizing plate 11 on the top face of the display surface 1a, and light reflected from the display surface 1a can be suppressed.
Also, in this structure, outside light 22 (including a scattering light caused by the anti-glare processing of the polarizing plates 11 and 12) is transmitted through the polarizing plate 12 and the quarter wavelength plate 10 to become a left circular polarization 23. The left circular polarization 23 is reflected from the surface of the quarter wavelength plate 6 to become a right circular polarization 24, the polarization 24 is transmitted through the quarter wavelength plate 10 to be converted into a vertical polarization, and then the vertical polarization is absorbed by the polarizing plate 12.
According to the aforementioned principle, reflection images among the display surfaces 1a and 2a and reflection of the outside lights 17 and 22 can be prevented on the display surfaces 1a and 2a.
Next, an example will be explained as a second exemplary embodiment with reference to
As shown in
The display surfaces 1a and 2a of the image display elements 1 and 2 are combined at each end having an angle θ therebetween of, for example, 90 degrees. The image display elements 1 and 2 are liquid crystal panels, and those display surfaces 1a and 2a have lenticular lenses (unillustrated) attached thereto as an optical system for displaying a stereoscopic image. Further, the polarizing plates 3 and 4 are arranged on the lenticular lenses. It is designed so that the polarizing plates 3 and 4 allow the image display element 1 to emit a horizontal polarization and the image display element 2 to emit a vertical polarization respectively.
For the image display elements 1 and 2 in the second exemplary embodiment of the invention, color liquid crystal panels having 640 horizontal pixels by 480 vertical pixels, and 32 mm horizontal by 50 mm vertical in screen sizes were used. The display surfaces 1a and 2a of the image display elements 1 and 2 were provided with 320 lenticular lenses having a lens pitch of 100 μm. A distance for observation between the viewpoint 13 and the stereoscopic image display element 1 and 2 was 400 mm, and angle of view (referred to 14 in
Further, because of functions of the polarizing plates 3 and 4, the quarter wavelength plates 5, 6, 9, and 10 (in
When an image was displayed on the display surfaces 1a and 2a using the above mentioned image display device, a stereoscopic image without a false stereoscopic image caused by a reflection image was presented to the observer, and a stereoscopic display device presenting a realistic image with high level of visibility was provided.
A stereoscopic image is obviously a virtual image. A reflection image is also a virtual image. Therefore, the reflection image is easily mistaken for the stereoscopic image. Display of a stereoscopic image is affected more adversely than display of a plane image is by the reflection image. Thus, the present invention has a greater effect.
Next, an example will be explained with reference to
The image display device according to the third exemplary embodiment is the image display device of the first exemplary embodiment (
Further, in the third exemplary embodiment, the image display elements 1 and 2 include an image processing circuit 77. The image processing circuit 77 transforms a multi-viewpoint image signal 75 at the viewpoint positions 1 to n so as to generate images ranging from a perspective projection transformation image 761 at a viewpoint position 1 to a perspective projection transformation image 76n at a viewpoint position n, and can present a geometrically valid stereoscopic image 74 as an animated image to the observer in real-time.
When an image was displayed on the display surfaces 1a and 2a using the above mentioned image display device, the observer was presented with a stereoscopic image without a false stereoscopic image caused by a reflection image. Therefore, a stereoscopic display device presenting a realistic image with high level of visibility was provided.
According to the above description, the device has a structure in which a light beam from the image display element 1 is converted into a horizontal polarization, and a light beam from the image display element 2 is converted into a vertical polarization. Now, another example will be explained as a fourth exemplary embodiment with reference to
In
In the fourth exemplary embodiment as shown in
According to an example in
A light beam (a horizontal polarization) directed from a pixel of the display surface 1a to the display surface 40a is converted by the quarter wavelength plate 5 into a right circular polarization 15, and then converted by the quarter wavelength plate 9 into a vertical polarization 16 which can be transmitted through the polarizing plate 11. The vertical polarization 16 transmitted through the polarizing plate 11 reaches the polarizing plate 12 arranged on a top surface of the display surface 40a. In the above, the polarizing plate 12 is arranged so that a polarization direction of polarization transmitted therethrough is orthogonal to one for the polarizing plate 11, and the plate 12 can absorb the vertical polarization 16. Therefore, light emitted from the display surface 1a is diminished at the polarizing plate 12 on the display surface 40a, and reflected light from the display surface 40a can be suppressed.
Further, in this structure, outside light 17 (including scattering light caused by the anti-glare processing of the polarizing plates 11 and 12) is transmitted through the polarizing plate 11 and the quarter wavelength plate 9 to become a right circular polarization 18. The right circular polarization 18 is reflected from a surface of the quarter wavelength plate 5 to become a left circular polarization 19, and then is transmitted through the quarter wavelength plate 9 to be converted into a horizontal polarization which is absorbed by the polarizing plate 11.
Furthermore, a light beam (a vertical polarization) directed from a pixel on the display surface 40a to the display surface 1a is converted into a left circular polarization 20 by the quarter wavelength plate 6, and then is converted by the quarter wavelength plate 10 into a horizontal polarization 21 capable of being transmitted through the polarizing plate 12. The horizontal polarization 21 transmitted through the polarizing plate 12 reaches the polarizing plate 11 arranged on the top surface of the display surface 1a. In the above case, the polarizing plate 11 is arranged so that a polarization direction of polarization transmitted therethrough is orthogonal to one for the polarizing plate 12, and the plate 11 can absorbed the horizontal polarization 21. Therefore, light omitted from the display surface 40a is diminished at the polarizing plate 11 on the top surface of the display surface 1a, and reflected light from the display surface 1a can be suppressed.
Further, in this structure, outside light 22 (including scattering light caused by the anti-glare processing of the polarizing plates 11 and 12) is transmitted through the polarizing plate 12 and the quarter wavelength plate 10 to become a left circular polarization 23. The left circular polarization 23 is reflected from a surface of the quarter wavelength plate 6 to become a right circular polarization 24, and then is transmitted through the quarter wavelength plate 10 to be converted into a vertical polarization which is absorbed by the polarizing plate 12.
According to the above described principle, the reflection images among the display surfaces and reflection light of the outside light 17 and 22 can be prevented on the display surfaces 1a and 40a.
In the first to fourth exemplary embodiments described above, the image display elements in a certain system are used in which parallax images with respect to an origin are spatially separated to be displayed on the display surfaces. However, the image display elements are not limited to the above cases. The image display elements may display a two-dimensional image on the combination of display surfaces of the image display elements.
The image display elements can employ liquid crystal panels, organic EL panels, plasma display panels, surface-conduction electron-emitter displays, or other flat display panels, however, it can also employ CRTs other than the panels, or panels with large number of pixels and large screen sizes. The image display elements are attached with polarizing films as necessary.
Further, an angle between the neighboring two image display elements may be 90 degrees or wider, and the combination of image display elements may be two or more. The optical system which is a part of the image display device may be a parallax barrier, a lens array for integral photography, or a pinhole array, instead of the lenticular lens. The hollow layer is not necessary if outside light can be reflected from a surface of the quarter wavelength plate in a display surface side. In addition, the hollow layer may be set in a different thickness, or may be filled with resin or the like instead of air.
The present invention has been explained in the above with reference to embodiments (and examples), however, the present invention is not limited to the aforementioned embodiments (and examples). A structure and details in the present invention can be varied within a scope of the invention as long as those skilled in the art can understand it.
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|---|---|---|---|
| 2007-057898 | Mar 2007 | JP | national |
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|---|---|---|---|---|
| PCT/JP2008/053916 | 3/5/2008 | WO | 00 | 9/1/2009 |
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| WO2008/108389 | 9/12/2008 | WO | A |
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