JP5412655B2 - 3D image display device - Google Patents

Description

  In the integral imaging, particularly in the rough integral imaging in which a plurality of pixels are observed from one lens when viewed from the observer, the element lens constituting the fly-eye lens is enlarged. The present invention relates to a three-dimensional image display device capable of suppressing image generation.

  An outline of a conventional integral imaging type three-dimensional image display apparatus is shown in FIGS. In the configuration of FIG. 1A, a convex lens array and a Fresnel lens as a large aperture condensing system are arranged in front of the display surface to present a real image to the observer. In the configuration of FIG. 1B, a display surface, a convex lens array, and a large-diameter condensing system are arranged near the observer, and a virtual image is presented to the observer. In FIG. 1C, a plurality of real images are presented to the observer to present a more improved sense of reality.

  Coarse Integral Imaging (CII: Coarse Integral Imaging) means that in Integral Imaging, the element lenses that make up a fly-eye lens are enlarged and multiple pixels are observed from one lens when viewed from the observer. (Non-Patent Document 1). Since this method generates a real image or a virtual image, it is known that this method is advantageous in generating a three-dimensional image that is lifted or recessed from a display (Non-Patent Document 2). On the other hand, in this method, there are many image quality problems due to the occurrence of optical distortion in the real and virtual images generated by the lens. In addition, since the element image is large, the deterioration of the quality of the stereoscopic image due to the discontinuity of the joint is also a serious problem.

  The inventors of the present invention have disclosed a coarse integral volume display method in which integral lenses are used to enlarge individual lenses constituting a fly-eye lens and multilayer the display panel portion (see Japanese Patent Application Laid-Open No. 2008-151). 015121). In this method, since a volumed real image (or virtual image) is observed, congestion adjustment contradiction is reduced. In addition, since the multi-viewpoint system is combined, the images displayed on the front and rear panels are not separated when viewed from an oblique angle by hearing the number of panels to some extent. Furthermore, occlusion (occlusion relationship between objects) and glossy surface can be expressed.

  In particular, since the stereoscopic image is presented near the viewer, the real image is generated by the coarse integral imaging method, fine parallax presentation is required. For this reason, the above-mentioned problems of aberration and joint discontinuity become prominent. As a solution, a volume display that displays only an edge portion of a video using a multi-layer monochrome panel is superimposed on a real multi-view video generated by rough integral imaging (Non-Patent Documents 3 and 4), an Integra There have been proposed a method of multilayering the display portion of the rouge imaging (Non-Patent Documents 5 and 6). In the former case, there is no optical distortion in the volume display, but there is a shift between the multi-view video and the volume display due to integral imaging. In the latter case, optical distortion occurs in the volume display itself. Therefore, in any of the methods, the stereoscopic image to be presented cannot realize sufficient image quality.

  As a method for solving the above problems, the inventors of the present invention have proposed a method of calculating the distortion of a generated real image and rendering the distorted display surface (Non-Patent Documents 7 and 8). ). As a result, it has been confirmed that the degradation of image quality due to optical distortion is greatly improved. Furthermore, in rough integral imaging, the panel is multi-layered, and the display of the depth sample type (Non-patent Documents 9 and 10) by DFD (Depth-fused 3D) is applied to the distorted multi-layer surface generated as the real image. The inventors have proposed a method to be applied, and this is called coarse integral volumetric imaging (CIVI) (Non-patent Documents 11 and 12). It has been confirmed that this method can eliminate discontinuity between both images generated between adjacent lenses and reduce congestion adjustment contradiction.

  Thus, although it is a rough integral display system that can realize a high-quality stereoscopic image, there is a problem that a false image is generated. As shown in FIG. 2, each element image forms an image not through the corresponding element lens but also through an adjacent element lens, and this appears as a false image.

  To cope with this, measures have been taken so far that only the part where the real image is generated is used as a viewing window and the other part is used as a wall to hide the false image (FIG. 2). However, there is a problem that the installation of the viewing window increases the overall volume of the apparatus.

  As described above, in the existing coarse integral display method and coarse integral volume display method, there remains a problem that a false image is generated around the image to be presented. Up to now, measures have been taken such as installing a wall that hides the false image, but this method increases the overall size of the apparatus due to the attachment of the wall. Accordingly, the present invention proposes a display device that suppresses false images in the rough integral display and the rough integral volume display by devising the backlight section.

JP 2008-015121 A

H. Kakeya, "Coarse integral imaging and its applications," SPIE proceedings Volume 6803 (2008). Opt. 46, 3766-3773 (2007). B. Lee, S. Jung, Si.-W. Min, and J.-H. Park, "Three-dimentional display by use of integral photography with dynamically variable image planes," Opt Lett. 26, 1481-1482 (2001 ). R. Yasui, I. Matsuda, H. Kakeya, "Combining volumetric edge display and multiview display for expression of natural 3D images," SPIE Proceedings Volume 6055 (2006). H. Ebisu, T. Kimura, H. Kakeya, "Realization of electronic 3D display combining multiview and volumentric solutions," SPIE Proceedings Volume 6490 (2007). Y. Kim, JH Park, H. Choi, J. Kim, S.-W. Cho, and B. Lee, "Depth-enhanced three-dimensional integral imaging by use of multilayered display devices," Appl. Opt. 45, 4334-4343 (2006). Y. Kim, H. Choi, J. Kim, S. -W. Cho, Y. Kim, J. Park, and B. Lee, "Depth-enhanced integral imaging display system with electrically variable image planes using polymer-dispersed liquid -crystal layers, "Appl. Opt. 46, 3766-3773 (2007). H. Kakeya and Y. Arakawa, "Autostereoscopic Display with Real-image Virtual Screen and Light Filters," SPIE Proceedings Volume 4660 (2002). H. Kakeya, "Real-Image-Based Autostereoscopic Display using LCD, Mirrors, and Lenses," SPIE proceedings Volume 5006 (2003). S. Suyama, H. Takada, K. Uehira, S. Sakai and S. Ohtsuka, "A Novel Direct-Vision 3-D Display using Luminance-Modulated Two 2-D Images Displayed at Different Depths," SID'00 Digest of Technical Papers, 54.1, pp. 1208-l211 (2000). S. Suyama, H. Takada and S. Ohtsuka, "A Direct-Vision 3-D Display Using a New Depth-fusing Perceptual Phenomenon in 2-D Displays with Different Depth," IEICE Trans. On Electron., Vol. E85- C, No. 11, pp. 1911-1915 (2002). H. Kakeya, "lmproving image quality or coarse integral volumetric display," SPIE Proceedings Volume 7237 (2009). H. Kakeya, T. Kurokawa, Y. Mano, "Electronic realization of coarse integral volumetric imaging with wide viewing angle," SPIE proceedings Volume 6803 (2010).

  We propose a three-dimensional image display device that can suppress false images in coarse integral display and coarse integral volume display by devising the backlight collar.

  As a method for removing a false image other than the viewing window, a method of surrounding each element image with a barrier between the element image display surface and the element lens is conceivable so that the element image does not pass through the adjacent element lens. However, in this method, the barrier has a three-dimensional structure, and accuracy is required for processing and assembly.

  Therefore, the present invention proposes a false image erasing method that has a simpler structure and can also save power. In the proposed method, as shown in FIG. 3, the light emission position of the backlight is limited, and a convex lens is arranged on the back for each element image. With this configuration, since there is no backlight on the optical path to the adjacent lens, it is possible to suppress false images without installing a wall. In addition, the light emission range of the backlight can be narrowed without reducing the luminance of the normal image.

  Therefore, the present invention is a three-dimensional image display device using an integral display method, in which light from a backlight is arranged in a first light collection system array in which a plurality of element lenses are arranged, an image display surface, and a second light collection. Through the system, it has a configuration that enters the eyes of the observer. Further, the focal length of the second light collecting system is fa, the focal length of the element lens is fb, the distance between the backlight and the first light collecting system array is fafb / (fa−fb), and the first light collecting system array. When the distance between the second condensing system is fa, each of the similar figures obtained by multiplying the lens shape of each element lens constituting the second condensing system by fb / (fa−fb) The backlight emits light within the range.

  The image display surface is composed of a plurality of display surfaces, and the light from the backlight is able to present a volumetric stereoscopic image by sequentially transmitting the plurality of display surfaces.

  Further, the depth information viewed from the observer is displayed on a plurality of display surfaces on the image display surface, so that a three-dimensional image having a deeper depth and a volume feeling can be presented.

  According to the present invention, a three-dimensional image display device in which false images are suppressed can be realized, and an image in which false images are suppressed can be provided to an observer who is displaced from the front.

An outline of a conventional integral imaging three-dimensional image display apparatus is shown. (A) arranges a convex lens array and a Fresnel lens as a large aperture condensing system in front of the display surface, and presents a real image to the observer, and (b) shows a display surface and a convex lens array near the observer. And a large-diameter condensing system are arranged to present a virtual image to the observer, and (c) presents a plurality of real images to the observer and presents a more improved sense of reality. Although this is a coarse integral display method that can realize a high-quality stereoscopic image, there is a problem that a false image is generated. Since each element image forms an image not through a corresponding element lens but also through an adjacent element lens, this appears as a false image. In order to cope with this, until now, measures have been taken so that only the portion where the real image is generated is used as a viewing window and the other portion is used as a wall to hide the false image. However, there is a problem that the installation of the viewing window increases the overall volume of the apparatus. 1 shows a false image erasing method proposed by the present invention. In the proposed method, the light emission position of the backlight is limited, and a convex lens is arranged on the back for each element image. With this configuration, since there is no backlight on the optical path to the adjacent lens, it is possible to suppress false images without installing a wall. In addition, the light emission range of the backlight can be narrowed without reducing the luminance of the normal image. In (a), the focal length of the second condensing system is fa, the focal length of the element lens is fb, the distance between the backlight and the first condensing system array is fafb / (fa−fb), and the first collection. When the distance between the optical system array and the second condensing system is fa, a similar figure obtained by multiplying the lens shape of each element lens constituting the second condensing system by fb / (fa−fb) The backlight is emitted within the respective ranges. In (b), a thick lens array is arranged on the viewer side. By doing so, a width that can block light at the joint between the element lenses is formed. Even if the light emission range of the backlight is actually set as theoretically, in some cases, processing errors or lens aberrations occur in the actual device, so that part of the light may leak to the adjacent element lens. However, if the light emission range of the backlight is restricted too much to prevent this leakage, the normal image that should be originally shown tends to be lost and darkened. Therefore, by eliminating the light emission range of the backlight and blocking the leaked light by the thickness of the joint portion of the lens, it is possible to achieve both false image erasure and normal image maintenance. By presenting a plurality of real images to the observer, a more improved realistic image is presented. This can be used when a stereoscopic image having a deeper depth is presented, and a stereoscopic image with a volume feeling can be presented. Also, by presenting a volumetric image, the video connectivity at the lens joint can be significantly improved. As shown in this figure, for example, by adopting a configuration in which the observer is surrounded by eight sets of the integral display units, a 360-degree three-dimensional image in which false images are suppressed can be presented to the observer. (A) The observation image in the case where the light emission range of the backlight is not limited and (b) the case where it is limited is shown. It can be seen that the false image can be suppressed by limiting the range of the backlight.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In the following description, devices having the same function or similar functions are denoted by the same reference numerals unless there is a special reason.

  FIG. 3A shows a main part of the three-dimensional image display device of the present invention. Light from the backlight enters the eyes of the observer through the first light collection system array, the image display surface, and the second light collection system in this order. The first light collection system array is a set of element lenses constituting the first light collection system, and the second light collection system is also constituted by a set of element lenses constituting the first light collection system. In addition, the image display surface includes one or more display surfaces, and the display surfaces are controlled by a display controller (not shown).

Here, the focal length of the convex lens array that is the second condensing system on the observer side is fa, the focal length of the back lens that is the first condensing system array is fb, and the diameter of the element lens is d. And the distance between the first light collection system array is fafb / (fa−fb), and the distance between the first light collection system array and the second light collection system is fa. In this case, the light emission range for preventing generation of a false image is a similar figure obtained by multiplying the lens shape of the element lens constituting the second condensing system by fb / (fa−fb) by calculation of geometric optics. It can be seen that the backlight should be emitted within the range of. Normally, the element lens uses a square or a regular hexagon, so if the lens shape is a square with one side d, the backlight is a square with one side dfb / (fa−fb), and if the lens shape is a regular hexagon with one side d, the backlight is It becomes a regular hexagon of one side dfb / (fa−fb), and at this time, the area of the light emission range is (fb / (fa−fb)) ² times, so if fb is reduced, significant power saving can be expected. In addition, the backlight portion can be made thin.

  In the example of FIG. 3B, a thick lens array is arranged on the viewer side. By doing so, a width that can block light at the joint between the element lenses is formed. Even if the light emission range of the backlight is actually set as theoretically, in some cases, processing errors or lens aberrations occur in the actual device, so that part of the light may leak to the adjacent element lens. However, if the light emission range of the backlight is restricted too much to prevent this leakage, the normal image that should be originally shown tends to be lost and darkened. Therefore, by eliminating the light emission range of the backlight and blocking the leaked light by the thickness of the joint portion of the lens, it is possible to achieve both false image erasure and normal image maintenance. This blocking may be positively performed by providing a blocking layer at the joint.

  However, this simple geometrical optics approximation is established only when the focal lengths fa and fb are relatively large compared to the lens diameter d. Due to the aberration, even if fb is excessively reduced, further improvement in power efficiency (reduction in the area of the backlight while keeping the luminance constant) cannot be realized.

  FIG. 5 shows the appearance of an actual machine manufactured based on the above principle. The element image and the lens constituting the lens array are both squares with a side of 30 mm, the lens array on the observer side has a focal length of 100 mm, and a plurality of lenses are overlapped on the back side of the element image so that the combined focal length is about 33 mm. A lens array is arranged.

  FIG. 6 shows observation images when (a) the light emission range of the backlight is not limited and (b) when it is limited. It can be seen that the false image can be suppressed by limiting the range of the backlight. However, the false image is not completely gone. This is thought to be due to light leakage.

  In this embodiment, the light emission range of the backlight is limited by installing a barrier. In this case, power saving cannot actually be realized. However, it is clear that wasted light can be reduced and power can be saved by using a backlight that emits light only at the opening of the barrier, for example, a backlight in which a large number of light sources with a similar area in the shape of the above-mentioned figure are arranged. .

  FIG. 4 presents a plurality of real images to the observer, and presents a more improved realistic image. This can be used when a stereoscopic image having a deeper depth is presented, and a stereoscopic image with a volume feeling can be presented. Also, by presenting a volumetric image, the video connectivity at the lens joint can be significantly improved.

  As shown in FIG. 5, for example, by adopting a configuration in which the observer is surrounded by eight sets of the integral display units, a 360-degree three-dimensional image in which false images are suppressed can be presented to the observer.

  Further, in the above description, only one person is shown as an observer. However, even if the position of the observer is changed, the above description is valid, so for many observers, the multi-viewpoint of the present invention can be achieved. Obviously, the stereoscopic image of the stereoscopic display device can be observed simultaneously.

DESCRIPTION OF SYMBOLS 1 Image display surface 2 1st condensing system array 3 2nd condensing system 4 Imaging surface 5 Observer 6 Display controller 7 Backlight

Claims (3)

A three-dimensional image display device using an integral display method,
The light from the backlight passes through the first condensing system array in which a plurality of element lenses are arranged, the image display surface, and the second condensing system in that order, and is incident on the observer's eyes.
The focal length of the second light collecting system is fa, the focal length of the element lens is fb, the distance between the backlight and the first light collecting system array is fafb / (fa−fb), and the first light collecting system array When the distance between the second light collecting systems is fa,
The backlight is caused to emit light within the range of similar figures obtained by multiplying the lens shapes of the respective element lenses constituting the second condensing system by fb / (fa−fb). 3D image display device.   The three-dimensional image display device according to claim 1, wherein the image display surface includes a plurality of display surfaces, and light from the backlight sequentially transmits the plurality of display surfaces. .   The three-dimensional image display device according to claim 2, wherein the depth information viewed from the observer is displayed on a plurality of display surfaces on the image display surface.

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