JP5017234B2 - Autostereoscopic system - Google Patents

Description

  The present invention relates to an autostereoscopic system for stereoscopic viewing with the naked eye (also simply referred to as a stereoscopic system or an autostereoscopic apparatus).

  In recent years, there has been a market trend for autostereoscopic displays using a light reproduction method that reproduces a natural three-dimensional light space, such as the integral photography method.

  Here, in order to improve the light beam density for reproducing the light beam space, Patent Document 1 discloses a technique for projecting a large number of projectors onto an optical system such as a microlens from different incident directions.

  FIG. 9 shows a principle configuration diagram of the autostereoscopic system disclosed in Patent Document 1. In FIG.

  Light rays from the projector group 41 are multiple projected onto the Fresnel lens 51 and output through a microlens array 52 placed in front of the lens. With this configuration, light from a plurality of pixels by the plurality of projectors 41 is incident on one microlens of the microlens array 52. Then, for example, when a light beam for n pixels enters a microlens from one projector, the light beam is once condensed at the focal length of the microlens and then emitted as a light beam in the n direction. For this reason, a user who observes an image in the light beam space of the stereoscopic vision system seems to output different information depending on the viewing direction of the light beam from one pixel.

  Based on this principle, information with parallax is input to the user's right eye and left eye, and the user feels a stereoscopic effect. Note that even if the Fresnel lens 51 is omitted, there is not much difference in practice, so that it is omitted in the following description. Further, the microlens array 52 may be a lenticular lens arranged in a cross shape, but full parallax can be realized by refracting light rays vertically and horizontally.

  At this time, the effect of light rays from a plurality of projectors entering one microlens of the microlens array 52 is that the position where the light is collected by the microlens lens depends on the angle of the light rays incident from the Fresnel lens 51. This phenomenon is observed as a phenomenon that shifts in a parallel direction on a plane parallel to the plane of the microlens array 52. Therefore, the user feels that the number of pixels has increased.

JP 2008-139524 JP

  FIG. 10 is a diagram illustrating the relationship between the projector group and the stereoscopic display area in Patent Document 1. In FIG. In Patent Document 1, as shown in FIG. 10, the three-dimensional light space expressed by the projector group 41 is an area between 21 and 22 in the figure (hereinafter, a 3D display area), and a microlens array or a cross lenticular. It is disclosed that the light distribution is designed to be symmetric with respect to the vertical direction (hereinafter referred to as the front direction) 5 of the refractive optical system 4. This presupposes the front direction of the refractive optical system 4 as the position of the user who observes the image by the autostereoscopic system. However, the position of the user observing the autostereoscopic system is not the front direction, but the user uses the refractive optical system 4 depending on the installation environment of the autostereoscopic system and the relative relationship between the autostereoscopic system and the position of the user's eyes. There are cases where it is limited to a certain range viewed from an oblique direction. In such a case, a large number of useless light rays are generated that do not reach the user's eyes, and the stereoscopic effect according to the number of projectors cannot be fully utilized.

  In addition, since the projector itself has a size and there is a limit to the density at which the projector is installed, effective use of light from the projector is an issue in order to improve the light density, which is important for expressing the stereoscopic effect. .

  Accordingly, an object of the present invention is to improve the stereoscopic effect by utilizing the light rays from the projector as little as possible in a situation where the user does not use the autostereoscopic system from the front direction.

  The autostereoscopic system of the present invention includes a refractive optical system that refracts light vertically and horizontally, and a plurality of projectors that are arranged with a deviation in the projection direction distribution with respect to the main axis direction of the refractive optical system.

  In another desirable aspect of the present invention, the plurality of projectors includes a first projector in which the projected light beam is directly incident on the refractive optical system, and a first projector in which the projected light beam is reflected by the reflective optical system and then incident on the refractive optical system. 2 projectors.

  According to still another desirable aspect of the present invention, a plurality of projectors includes a first projector in which light rays to be projected are transmitted through the half mirror and incident on the refractive optical system, and the light rays to be projected are reflected by the half mirror. A second projector incident on the refractive optical system.

  In another desirable aspect of the present invention, each of the plurality of projectors includes a lens having a depth of focus equal to or greater than a difference between a longest distance and a shortest distance at which a light beam projected from each projector reaches the refractive optical system.

  According to still another desirable aspect of the present invention, the distribution of the projection direction is biased with respect to the principal axis direction of the refractive optical system by shifting the lens of each of the plurality of projectors.

  According to the present invention, since the light rays from the projector can be used effectively in accordance with the design of the viewing area (stereoscopic display area) that assumes the usage method, a naked-eye stereoscopic system with a higher stereoscopic effect is provided. be able to.

  Embodiments of the present invention will be described with reference to Examples 1-3.

  FIG. 1 shows an apparatus configuration example of the autostereoscopic system of this embodiment. Each projector in the projector group 41 is connected to PCs 42 to 44 that output video signals. Each of the PCs 42 to 44 is a personal computer having a video interface (video IF) or a control device replacing the personal computer. The content data 46 to 48 are respectively stored in the storage devices of the PCs 42 to 44. The PCs 42 to 44 are controlled from the control PC 45 via the network 49, and the content data 46 to 48 are synchronized with the projector group 41. Is displayed.

  FIG. 2 is a diagram illustrating the relationship between the projector group 41 and the stereoscopic display area according to the present embodiment. The relationship between the arrangement of the projector group 41 and the stereoscopic display area will be described with reference to FIG. As a method of using the stereoscopic system, it is assumed that the user often observes from the right region in FIG. 10 (the end 22 side of the stereoscopic display region rather than the front direction 5). At this time, as shown in FIG. 2, the position of the projector group 41 is shifted to the left with respect to the front direction 5, and the projection direction onto the refractive optical system 4 of the projectors 1 to 3 is tilted so that the stereoscopic display area is illustrated. The region is changed to a region between 6 and 7 on the right side of FIG. This is because the stereoscopic display area is an area where light rays projected from the projector group 41 exist, and this area can be determined by a distribution obtained by combining all the projection directions of the projector group 41. In this way, the change of the stereoscopic display area is realized by making the distribution in the projection direction of the projector group 41 biased with respect to the main axis direction of the refractive optical system 4.

  The relationship between the tilt of the projector and the stereoscopic display area at this time will be described in more detail. The direction of the light beam output from one optical element of the refractive optical system 4 will be described with reference to FIG. For example, as shown in FIG. 3A, when a light beam 72 is incident on one optical element 71 from a projector, a direction 73 having a spread of an angle α corresponding to the size and focal length of the optical element 71 is centered. Is emitted as a light beam 74. This corresponds to the state of light rays from the central projector in FIG. 10 toward the central optical element of the refractive optical system 4. Here, as shown in FIG. 3B, if the incident light from the projector to the refractive optical system 4 is tilted to the right by an angle θ (in a direction 75 that forms an angle θ with respect to the direction 73), the optical element 71 The central direction 76 of the light beam 77 emitted from the light source is a direction 76 in the figure inclined by the angle θ. At this time, the spread angle α ′ of the emitted light beam 77 is determined by the size of the optical element 71 and the focal length. As described above, when the observation position of the image in the light space of the stereoscopic system is not the front direction of the stereoscopic system, the projection direction of the projector is determined according to the angle between the center direction of the stereoscopic display area and the refractive optical system 4. . At this time, it is desirable that the observation position is in the center direction of the stereoscopic display area (direction 76 in FIG. 3B). However, since there is a restriction due to the depth of focus of the projector described later, the observation position is within the restriction range. The projection direction of the projector is determined so as to approach the center direction of the stereoscopic display area.

  Note that the direction in which the projector is tilted is in-plane rotation in the two-dimensional cross-sectional direction so that the explanation is easy to understand. However, it may be rotated in the vertical direction (front direction or depth direction) with respect to the drawing of FIG. In this case, the stereoscopic display area moves in the vertical direction of the drawing of FIG.

  Furthermore, as described above, when the stereoscopic display area is changed, the image signal to be displayed is changed accordingly. Information on a three-dimensional object to be displayed in each light beam direction may be displayed according to the direction of each light beam emitted from the refractive optical system 4.

  Such an arrangement makes it possible to effectively use the information and light rays used in the region 8 that is not the user's observation position shown in FIG. 2 as the information and light rays in the region 9, and use the autostereoscopic system. Effective use of information and light rays corresponding to the above positional constraints becomes possible.

  At this time, the depth of focus when attention is paid to a certain projector will be described with reference to FIG. When the projection range of one projector 1 in the projector group 41 is the projection range 31 in the figure, the range in which the projector 1 is in focus (hereinafter referred to as the depth of focus) is set to be greater than or equal to the distances A to B in the figure. . The distance A is the shortest distance from which the light beam projected from the projector 1 reaches the refractive optical system 4, and the distance B is the longest distance. Here, the permissible value of the focal depth is relatively defined according to the assumed usage condition of the autostereoscopic system. For example, when it is allowed to mix about half of the ray information adjacent to certain ray information, it is defined to allow a scattering size of 0.5 pixels.

  In order to increase the depth of focus (increase the in-focus range), there are methods such as reducing the projector aperture ratio, and using a lens shift that achieves the same effect. In the lens shift, instead of tilting the projection direction of the projector 1 from the front direction of the refractive optical system 4, the lens of the projector 1 is translated in a direction perpendicular to the projection direction, and the in-focus surface by the lens of the projector 1 is not changed. In addition, this is a known method of translating the projection direction. When this lens shift is used, the in-focus surface by the lens of the projector 1 remains the surface of the refractive optical system 4, so there is no need to consider the depth of focus.

  In the present embodiment, a method of using a mirror to tilt the stereoscopic display area from the front direction by effectively utilizing the internal space of the autostereoscopic system will be described with reference to FIG. FIG. 5 shows a part of the autostereoscopic display device 63 viewed from the lateral direction. The refractive optical system 4 on which an image is displayed is vertically installed at a certain height, and a stereoscopic observation region 64 from a child to an adult assumed as a user is below the front direction of the refractive optical system 4. .

  At this time, if the stereoscopic display region is shifted downward from the front direction of the refractive optical system 4, the refractive optical system 4 exists at a certain height, so that the stereoscopic display device 63 is positioned below the autostereoscopic display device 63. There is room for space. Therefore, the reflective optical system 62 is used to reflect light rays from the projector 61 installed on the lower side of the autostereoscopic display device 63 and to enter the refractive optical system 4, thereby effectively utilizing the space. , Increase the light density. The reflection optical system 62 uses a mirror (preferably total reflection) having a size larger than the projection range of the projector 61 using the reflection optical system, is disposed at a position facing the projector, and the direction in which the light beam from the projector 61 is reflected is The direction of the stereoscopic observation region to be designed is set so as to enter the refractive optical system 4.

When the projection distances of the projectors 1, 2 and 61 change, it is desirable to use a zoom optical system so that the projected areas incident on the refractive optical system are approximately equal. For example, if the projection distance of the projectors 1 and 2 is L1, half of the angle of view is β, the projection distance of the projector 61 is L2, and half of the angle of view is γ, the angle of view is as shown in the following equation. Just zoom.
γ = tan ^-1 {(L1 / L2) tanβ}
By doing so, the light density from each projector expressed by being condensed by one lens element of the refractive optical system 4 becomes substantially equal.

  Further, it is desirable to project from each projector to the same range as the refractive optical system 4. However, as shown in FIG. 5, even if the size of the projected area changes slightly or the projected area protrudes beyond the refractive optical system 4, the light distribution and the density thereof are not uniform. Although the quality of the display of the stereoscopic system is lowered, it is acceptable depending on the application. At this time, it is assumed that the inner surface of the autostereoscopic display device 63 uses a color or material that absorbs light so that unnecessary reflection does not occur. For example, it may be covered with a black felt-like material. In this way, by allowing a certain amount of error, the autostereoscopic system can be easily assembled and adjusted.

  Next, an embodiment of a table top type autostereoscopic system will be described with reference to FIGS. FIG. 6A is a side view of a table top type autostereoscopic device, and FIGS. 6B and 7 are views of the device viewed from above.

  A half mirror 73 is installed inside the autostereoscopic display device 63. The half mirror 73 substantially equalizes the rate of transmitting the light beams of the projectors 1 and 2 installed on the bottom surface of the autostereoscopic display device 63 and the rate of reflecting the light beams of the projectors 71 to 72 disposed on the side surfaces. The inner surface of the autostereoscopic display device 63 uses a color or material that absorbs light.

  Here, taking advantage of the feature that the autostereoscopic system is capable of expressing full parallax, a refractive optical system is assumed as shown in FIG. 6 shows an example of a projector arrangement that realizes the stereoscopic observation region 64 by the user.

  In order for the projectors 1 and 2 to realize the stereoscopic observation region in the right direction in FIG. 6A, the projectors 1 and 2 are arranged to be inclined in the right direction in the drawing. The tilt angle is determined in accordance with the angle of the designed stereoscopic observation region with respect to the refractive optical system 4 in consideration of the spatial constraints on the sizes of the projectors 1 and 2 and the inside of the apparatus and the above-described limitations on the depth of focus of the projector.

  Further, as shown in FIG. 6A, the projectors 71 to 72 have the same optical axis as the projectors 1 to 2 with respect to the mirror surface (reflection surface) of the half mirror 73 when the apparatus is viewed from the side. It installs in the position of the plane symmetry. Further, as shown in FIG. 6 (b), when the apparatus is viewed from above, 1/2 (w / 2 in the figure) with respect to the installation interval (w in the figure) of the projectors 1 and 2 on the bottom surface. Side projectors 71 to 72 are arranged at the shifted positions.

  With this configuration, the projection distance from the side projectors 71 to 72 to the refractive optical system 4 is the same as that when the projection is performed on the bottom surface of the half mirror 73. There are advantages such as making the corners the same.

  According to the embodiment as described above, it is possible to effectively utilize the limited space in the apparatus, increase the light density, and improve the quality of the stereoscopic image.

  Here, in the above description, it is assumed that the half mirror 73 having substantially the same transmittance and reflectance is used. For example, if the half mirror has a transmittance of 40% and a reflectance of 20%, the transmitted light beam is transmitted. The brightness may be adjusted by halving the brightness of the projectors 1 and 2 to be output.

  In the above description, the side projectors 71 to 72 are arranged symmetrically with respect to the bottom projectors 1 and 2 around the half mirror 73. However, the side projectors 71 to 72 are not necessarily arranged symmetrically by changing the angle of view of the projector. .

  Further, the refractive optical system 4 may be installed at an angle as shown in FIG. 8 instead of being horizontal with respect to the installation surface of the bottom projectors 1 and 2. By installing in this way, the depth of focus required for the projectors 2 and 71 can be reduced, and the quality of the stereoscopic image can be improved.

  According to the above embodiment, since the light rays from the projector can be effectively used in accordance with the design of the viewing area (stereoscopic display area) assuming the usage method, the autostereoscopic system with higher stereoscopic effect can be achieved. Can be provided.

It is an apparatus structural example of an autostereoscopic system. It is a figure explaining the relationship between a projector group and a three-dimensional display area. It is a figure explaining the direction of the light ray output from the optical element of a refractive optical system. It is a figure explaining the depth of focus when paying attention to a projector. It is the figure which looked at the autostereoscopic display device in the case of using a mirror from the horizontal direction. It is a block diagram of a table top type autostereoscopic device. It is the figure which looked at the table top type autostereoscopic device from the top. It is another block diagram of a table top type autostereoscopic device. It is a principle block diagram of an autostereoscopic system. FIG. 6 is a diagram illustrating a relationship between a projector group and a stereoscopic display region in Patent Document 1.

Explanation of symbols

1-3, 61, 71, 72: Projector, 4: Refractive optical system, 41: Projector group, 62: Reflective optical system, 63: Autostereoscopic display device, 64: Stereoscopic observation area, 73: Half mirror.

Claims (7)

A refractive optical system that refracts light rays vertically and horizontally;
The distribution of the projection direction, have a plurality of projectors arranged to have a bias to the main axis direction of the refractive optical system,
The biased arrangement is such that the plurality of projectors are shifted to the left or right from the center of the refractive optical system with respect to the front direction, and a three-dimensional display region that reproduces a three-dimensional light space is the refractive optical. An autostereoscopic system , wherein a plurality of projectors are arranged with their projection directions onto the refractive optical system tilted so as to tilt to the right or left with respect to the center of the system. The plurality of projectors include a first projector in which a light beam to be projected is directly incident on the refractive optical system, and a second projector in which the light beam to be projected is incident on the refractive optical system after being reflected by the reflective optical system. The autostereoscopic system according to claim 1. 3. The autostereoscopic system according to claim 2, wherein a projected area of the first projector onto the refractive optical system is substantially equal to a projected area of the second projector onto the refractive optical system. The plurality of projectors are:
A first projector in which a light beam to be projected passes through a half mirror and enters the refractive optical system;
2. The autostereoscopic system according to claim 1, further comprising: a second projector that projects light rays reflected by the half mirror and then enters the refractive optical system. 3. With respect to the half mirror reflecting surface, the first projector and the second projector are placed in plane symmetry positions where the optical axes of the first projector and the second projector are equidistant. The autostereoscopic system according to claim 4, wherein the autostereoscopic system is arranged. 6. Each of the plurality of projectors includes a lens having a focal depth equal to or greater than a difference between a longest distance and a shortest distance at which a light beam projected from each projector reaches the refractive optical system. The autostereoscopic system according to any one of the preceding claims. 7. The projector according to claim 1, wherein each of the plurality of projectors is shifted by a lens so that the distribution in the projection direction is biased with respect to the principal axis direction of the refractive optical system. Autostereoscopic system.

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