Display device

Abstract

The present invention realizes simple three-dimensional display by providing a region in which diffused lights from adjacent projection devices overlap one another in the reachable range of the diffused lights.　The present invention comprises: a retroreflective diffusion screen 12 that is provided with a retroreflective material 13 and a transmissive diffusion layer 14; and three or more projection devices 20 that project images on the retroreflective diffusion screen 12. The images projected from the adjacent projection devices 20 are projected so as to be mutually diffused in the state of overlapping one another. The images reflected on the retroreflective diffusion screen are observed from positions behind the projection devices 20.

Description

[Technical Field]

[0001] The present invention relates to a display device that can relatively easily produce three-dimensional images. [Background technology]

[0002] To realize a multi-viewpoint naked-eye 3D display device (3D screen) with motion parallax, a method has been disclosed in which images are projected from multiple angles using a transmission screen with a narrow diffusion angle (Patent Document 1), and a display method has been disclosed in which a reflective screen is used, with a small number of image sources and projectors, and smooth switching of viewpoints is possible even when motion parallax occurs (Patent Document 2).Motion parallax is the parallax that occurs when the observer's viewpoint moves.

[0003] Also known are a display device that has a cylindrical reflective screen and multiple projection devices arranged above the cylindrical part (Patent Document 3), and a reflective display device that uses a retroreflector as the reflective screen (Patent Document 4).As for the reflective screen, an optical configuration that uses a Fresnel lens and diffusion to enable observation from all directions has been disclosed (Non-Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-121748 [Patent Document 2] Japanese Patent Application Publication No. 2018-195998 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-232634 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-66442 [Non-patent literature]

[0005] [Non-Patent Document 1] M. Makiguchi, D. Sakamoto, H. Takada, K. Honda and T. Ono, "Interactive 360-Degree Glasses-Free Tabletop 3D Display," UIST2019 Proceedings of the 32nd Annual ACM Symposium on User Interface Software and Technology, pp. 625-637, New Orleans, LA, USA, Oct. 2019. Summary of the Invention [Problem to be solved by the invention]

[0006] The method of Patent Document 1 projects viewpoint images seen from multiple directions from multiple directions, allowing 3D images to be observed with the naked eye from multiple directions, but it has the problem that a projector needs to be installed behind the screen, making the entire device larger and limiting installation locations. The method of Patent Document 2 uses a reflective screen to make the entire device smaller, but the observation range is limited to observation from near the front of the screen, as in Patent Document 1. The method of Non-Patent Document 1 uses a configuration in which a reflective lens and a diffusion screen are arranged horizontally to allow observation from all around, but because the projected image is observed from the specular reflection direction, a large projection system needs to be placed above and opposite the viewer.

[0007] Patent Document 3 describes a cylindrical screen constructed using a retroreflector and a diffusion layer, with multiple projectors placed above the screen and the direction of diffusion adjusted to display a clear three-dimensional image. However, this requires the installation of multiple projectors and a large-scale stand for mounting the projectors, which results in a problem of the display device itself becoming large in size.

[0008] The device in Patent Document 4 uses a retroreflector and places a light modulation layer using an LED switch between the reflector and the substrate to achieve a display device with a high contrast ratio, with the main focus being on increasing the contrast ratio.

[0009] In Patent Documents 1 and 2 and Non-Patent Document 1, a configuration such as a projector is required even in areas where no observer is present, resulting in a large-scale device configuration.

[0010] This invention has been made in consideration of these problems, and proposes a display device that provides naked-eye stereoscopic viewing that can significantly reduce the number of projection devices used, saves installation space, and realizes a compact, personal display system. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, a display device according to the present invention as set forth in claim 1 comprises a retroreflective diffusion screen having a retroreflector and a transmissive diffusion layer, and two or more projection devices that project an image onto the retroreflective diffusion screen, wherein a portion of the diffused light among the reflected light of an image projected from one of the adjacent projection devices is projected so as to overlap a portion of the diffused light among the reflected light of an image projected from the other projection device adjacent to the one of the projection devices, and The reach of the diffused light from the adjacent projection devices reflected by the retroreflective diffusion screen is characterized in that, when the rear of the projection devices is set as an observation position, there are reach areas of the diffused light that overlap each other at this observation position.

[0012] At least three adjacent projection devices are prepared, and the images projected from the adjacent projection devices are part By configuring the images to overlap and diffuse, it is relatively easy to create three-dimensional (3D) images that can be observed as stereoscopic images with motion parallax.

[0014] When the observation position is set to a position behind the projection device, 3D images can be observed if the ranges of light that have been diffused from the projection device overlap each other at this observation distance.

[0015] In the display device of the present invention described in claim 3, the reach areas of overlapping diffused light at an observation position behind the projection device are characterized in that the horizontal widths of adjacent reach areas are equal on a distribution diagram of the brightness characteristics of the projection device.

[0016] By making the overlapping areas of coverage at the observation position equal in horizontal width on the distribution map of the projection device's brightness characteristics, the change in the brightness level of the composite image can be kept small even when the observer moves horizontally, allowing the viewer to enjoy natural 3D images. In the display device according to the present invention as set forth in claim 4, the overlapping portions at the observation position behind the projection device are The aforementioned The area where the diffused light reaches is an area that is symmetrical with respect to a central axis, which is a perpendicular line to the horizontal axis of the distribution map that passes through a point where adjacent luminance levels intersect on the distribution map of the luminance characteristics of the projection device, and the width of each of the areas with adjacent luminance levels is equally divided horizontally with respect to the perpendicular line as the central axis. 。 By making the overlapping areas of reach at the observation position symmetrical with a line perpendicular to the horizontal axis of the distribution chart of luminance characteristics, which passes through the point where adjacent luminance levels intersect on the distribution chart, and by making the width of each area of ​​adjacent luminance levels equally divided horizontally with the perpendicular line as the central axis, it is possible to minimize changes in the luminance level of the composite image even when the observer moves horizontally, allowing the viewer to enjoy natural 3D images.

[0017] The display device according to the present invention as set forth in claim 5 is characterized in that a plurality of projection devices are arranged in a plurality of directions across the retroreflective diffusing screen, and images from the plurality of directions are projected onto the retroreflective diffusing screen in a superimposed manner, so that each image can be observed independently from each of the plurality of directions. By arranging, for example, three projection devices (projector arrays) circumferentially around a retroreflective diffusion screen in multiple directions, for example, at angular intervals of 120°, and projecting images from these projector arrays onto the same diffusion screen, it is possible to limit the observation of images to the observer's surroundings or to display different information for each projector array. [Effects of the Invention]

[0018] According to this invention, by using a retroreflective diffusion screen and projecting images from adjacent projection devices so that they overlap and diffuse each other, the number of projection devices for 3D images can be significantly reduced, thereby saving installation space and providing a personalized display device.

[0019] This invention does not use any complex optical systems, so it widens the three-dimensional viewing angle (range), eliminates stray light, and produces bright, high-quality 3D images. Because the only components are a projection device and a retroreflective diffusion screen, it is possible to realize a compact, portable, and naked-eye 3D image display device. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a plan view of a main part showing an example of a display device according to the present invention; [Figure 2] FIG. 2 is a side view of FIG. [Figure 3] 1 is a cross-sectional view of a main part of an example of a retroreflective diffusion screen. [Figure 4] FIG. 10 is a cross-sectional view of a main part showing another example of a retroreflective diffusion screen. [Figure 5] FIG. 1 is a cross-sectional view for explaining retroreflection and diffusion. [Figure 6] FIG. 10 is a diagram illustrating the luminance characteristics of the imaging device. [Figure 7] FIG. 1 is a configuration diagram showing a projection relationship when a projector array is used. [Figure 8] FIG. 8 is a side view of FIG. 7 with a part cut away. [Figure 9] FIG. 2 is a partially cross-sectional rear view of the projector array as viewed from the rear side. [Figure 10] FIG. 10 is a plan view of a main part showing another example of a display device according to the present invention. [Figure 11] 10 is a side view of a main part showing another example of use of the display device according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a display device 10 according to the present invention is composed of a retro-reflective diffusion screen (hereinafter referred to as the diffusion screen) 12 and a projection device 20 that projects an image onto this diffusion screen 12. In the configuration of FIG. 1, in which the diffusion screen 12 is arranged on a plane, images are projected from a plurality of image capturing devices 20 arranged diagonally above the diffusion screen 12 as shown in FIG. 2, and an observer views the diffusion screen 12 from near point S behind the image capturing devices 20.

[0022] By projecting multiple images from the projection device 20 onto the diffusion screen 12 in an overlapping manner, the same image can be observed stereoscopically with the naked eye. To enable observation as a stereoscopic image (stereoscopic image), multiple projection devices 20 are prepared as described below, and the images used are multiple images of the same subject captured from positions spaced apart at equal angles to the left and right of the center.

[0023] The image light incident on the diffusion screen 12 is transmitted as diffused light that is diffused within a predetermined angle range, then returns to the direction of incidence as retroreflected light, and then returns to the vicinity of the direction of incidence as diffused light that is diffused once more. Of reflected light This diffused light is used to view the image.

[0024] In this case, the images projected from the adjacent projection devices (also called projectors) 20 are Partially overlapping The image is projected as shown. cormorantBy configuring it in this way, it is possible to realize three-dimensional images (3D images) that can be observed relatively easily as stereoscopic images.

[0025] The reach range of the diffused light from the projection device 20 is such that when the observation position is behind the projection device 20 (near point S in Figure 2), the diffusion area of ​​the diffused light is set so that there are overlapping reach areas of the diffused light at this observation position, and 3D images can be observed in the overlapping areas. In other words, by projecting the image projected from one of the adjacent projection devices so that a portion of the diffused light among the reflected light of the image projected from the other projection device adjacent to the one projection device overlaps with a portion of the diffused light among the reflected light of the image projected from the other projection device adjacent to the one projection device, a 3D image can be observed in the overlapping area. The brightness characteristics (brightness level) of the diffusion layer 14 are adjusted so that the brightness levels in the areas reached by the overlapping diffused light at the observation position behind the projection device 20 are equal in width in the horizontal direction (the direction in which the image capture devices 20 are arranged side by side). The brightness characteristics in Figure 6 are an example when a diffusion layer 14 with a single layer structure (Figure 3), which will be described later, is used. By setting the brightness level so that the horizontal width is equal, it is possible to minimize fluctuations in the brightness level of the image (3D image) that can be observed between projection devices even when the viewer moves horizontally, allowing the viewer to enjoy natural 3D images. The area reached by the overlapping diffused light at the observation position behind the projection device 20 is preferably an area that is symmetrical with respect to a line perpendicular to the horizontal axis of the distribution diagram of the brightness characteristics, passing through the point where adjacent brightness levels intersect, as shown in Fig. 6, and is preferably adjusted so that the width of each area of ​​adjacent brightness levels is equally divided horizontally (in the direction in which the image capture devices 20 are arranged) around the perpendicular line. By setting the brightness levels to be equally divided horizontally, it is possible to minimize fluctuations in the brightness level of images (3D images) that can be observed between projection devices even when the viewer moves horizontally, allowing the viewer to enjoy natural 3D images.

[0026] The retroreflective diffusion screen 12 shown in Fig. 1 is composed of a retroreflective material 13 and a transmissive diffusion layer 14. The retroreflective material 13 shown in Figs. 3 and 4 is a flexible retroreflective film or sheet (such as the Reflector RF-A series from Nippon Carbide Corporation) based on a thin PET or acrylic plate, with microbeads or microprisms embedded in its surface. The transmissive diffusion layer (hereinafter referred to as the diffusion layer) 14 is a film-like material such as polyester or acrylic with a specified haze value (such as the non-glare low-reflection film from Tokyo Syscon Corporation).

[0027] The relationship between the retroreflecting light of the retroreflector 13 and the diffused light of the diffusion layer 14 is as shown in Figure 5. The retroreflecting light and retroreflective light are reflected toward the optical axis (projection center) Qo of the projection device 20, but the presence of the diffusion layer 14 causes the reflected light to diffuse slightly by the width of the diffusion angle Vb, thereby widening the diffusion range of the reflected light.

[0028] Depending on the structure of the diffusion layer 14, moire may occur due to the relationship between this structure and the pixel pitch of the projected image, or speckle noise, a glaring noise that resembles finely separated RGB colors, may occur, degrading the image quality, but this can be reduced by using a different diffusion material with a different structure or by using a multi-layer structure. It is desirable to obtain ideal diffusion characteristics with only a single diffusion layer 14.

[0029] The example in Figure 3 is realized with a single layer, and in this example, the diffusion screen 12 is constructed by attaching a diffusion layer 14 with a haze value of "23" directly to the upper surface of the retroreflective material 13. The diffusion characteristics (brightness characteristics) including the diffusion layer 14 will be described later.

[0030] The example in Figure 4 is a two-layer structure, in which diffusion layers with different haze values ​​are used in layers. In the example shown, the first diffusion layer 14a has a haze value of "23," while the second diffusion layer 14b has a haze value of "16," thereby achieving ideal brightness characteristics. The thickness of the first and second diffusion layers 14a and 14b is approximately 3 mm. In the two-layer structure, the reflected light from the retroreflector 13 passes through two diffusion layers 14, so the diffusion angle of the diffusion layer 14 is set to half the distance between the optical axes of adjacent imaging devices 20, as described below.

[0031] The haze value of the diffusion layer 14 is the percentage (%) of light that reaches the measurement point (S) from the light source (point P in Figure 2), so for example, when the haze value is "30", 30% of the light reaches the measurement point as is, and 70% of the light is bent and dispersed at different angles. Most diffusion layers generally have an omnidirectional diffusion angle of 360° or 180°, and when the haze value is small, most of the light is concentrated in a direction that is close to a straight line. In this example, since the installation interval between adjacent imaging devices 20 is narrow, a diffusion layer 14 with a small diffusion angle for reflected light is used.

[0032] Next, a description will be given of the luminance characteristics of the retroreflective diffusing screen 12. The diffusing layer 14 has a single layer structure as shown in FIG.

[0033] In Fig. 6, curves La, Lb, and Lc represent the luminance levels of diffused light projected from three projection devices 20A, 20B, and 20C (luminance levels of diffused light). All of these curves have luminance characteristics (single-peak characteristics) close to a normal distribution centered on the projection centers Qo, Qa, and Qb (see Fig. 1). The diffusion width, which indicates the diffusion angle described above, is generally defined as the half-value width Z of the luminance level of the diffused light, as shown in Fig. 6, or as the width between inflection points in the case of a Gaussian distribution (normal distribution).

[0034] To realize 3D images, the size of the diffusion angle from the diffusion screen 12 (the range of diffused light) is based on a light range that is twice the optical axis spacing (angles Ra and Rb) of adjacent projection devices 20 as shown in Figure 7, and the diffusion width of the diffused light must be the same as the optical axis spacing (angles Ra and Rb) of adjacent image capture devices 20 as shown in Figures 6 and 7. Therefore, the diffusion width of the diffused light matches the range of reach X of overlapping diffused light among adjacent diffused light as shown in Figure 6. The width of the diffused light, that is, the diffusion angle, does not match the haze value, but the diffusion angle is approximately 1 / 10 of the haze value of the diffusion layer 14.

[0035] When the observation position is behind the projection device 20, the reach range of the diffused light from the projection device 20 is such that, at this observation position S (Fig. 2), by providing overlapping reach areas X of the diffused light as shown in Fig. 6, when the viewpoint position is moved, adjacent images change smoothly, allowing the parallax to change gradually, resulting in a natural motion parallax. Because the observer's eyes observe from different observation positions, natural 3D images with different parallax between the eyes can be observed. 6, it is preferable that the composite luminance level of the luminance levels in a predetermined section sandwiching the point Ca where the adjacent luminance levels intersect is as close as possible to the composite luminance level of the adjacent luminance levels, and for this reason, it is desirable that the point Ca where the adjacent luminance levels intersect is close to half the value of the adjacent luminance level. In particular, when using a diffusion layer with luminance characteristics that are closer to a normal distribution rather than a linear luminance characteristic, the size of the diffusion angle and the projection angle of the adjacent projectors are determined taking into consideration minimizing the change in composite luminance in the overlap region Y as much as possible.

[0036] The curve Ls shown by the dashed line in Figure 6 indicates the composite brightness level. As described above, the diffusion width of the diffused light is selected to be the optical axis distance (angles Ra and Rb) between adjacent projection devices 20, so that the change in the composite brightness level can be made smooth as shown by the dashed line, realizing a natural 3D image. Figure 6 also shows the relationship between the overlapping area X, overlapping area Y, and half-value width Z. It is preferable that the reach area X of the overlapping diffused light at the observation position behind the projection device 20 be such that adjacent areas X have equal widths in the horizontal direction on a distribution diagram of the luminance characteristics of the projection device 20 illustrated as an example in Fig. 6. It is also more preferable that the reach areas X, Y of the overlapping diffused light at the observation position behind the projection device 20 be areas (areas where the luminance levels change symmetrically) that have a line-symmetric shape with respect to a line perpendicular to the horizontal axis of the distribution diagram that passes through points Ca and Cb where the adjacent luminance levels intersect, on the distribution diagram of the luminance characteristics of the projection device 20 illustrated as an example in Fig. 6, and that the widths of the areas X, Y of the adjacent luminance levels are divided equally in the horizontal direction with the perpendicular as the central axis. In this way, by making the horizontal widths of adjacent regions X equal, or by providing regions that are symmetrical about a line perpendicular to the horizontal axis of the distribution chart that passes through points Ca and Cb where adjacent luminance levels intersect, and by providing luminance level diffusion characteristics that divide the widths of each of adjacent luminance level regions X and Y equally in the horizontal direction about the perpendicular line as the central axis, it is possible to minimize fluctuations in the luminance levels of images (3D images) that can be observed between projection devices even when the viewer moves horizontally, allowing the viewer to enjoy natural 3D images.

[0037] Next, a description will be given of the projection device 20. In order to realize a stereoscopic image, three or more projection devices (hereinafter referred to as projectors) are used. The following example shows the case where three devices are used.

[0038] 1, the diffusion screen 12 is 500 to 600 mm square, and when the projection center Qo of the central projector 20A faces the screen center P, the image is projected from a height of about 300 mm above a position about 250 to 300 mm away from the screen edge Pb (the midpoint of Da from the center) (FIG. 2), with an elevation angle of 25° to 30°. At this time, the viewer views the image from near position S (elevation angle of about 40°) about 700 mm above a position Dc (about 700 mm) away from the screen edge Pb and about 300 mm away from it.

[0039] When you want to enjoy stereoscopic (3D) images, you can view the images on the diffusion screen 12 while moving around the periphery of the stand 18 as shown in Figure 1, and the stereoscopic images can be observed in the overlapping areas passing between projectors 20C and 20A and between 20A and 20B.

[0040] Human parallax is used to realize such 3D images with the naked eye. In general 3D displays using parallax, there is no overlapping area that takes into account the combination of brightness levels of images from adjacent projectors, so the projection distance between each projector is set to be equal to or less than the interocular distance of the human eye, which is generally 62 to 65 mm or less.

[0041] The configuration and method described in this embodiment have an overlapping area that takes into account the combination of the brightness levels of images from adjacent projectors, as described above, and is therefore characterized by the fact that 3D images can be observed with the naked eye not only at or below the interocular distance but also in the projection distance area between each projector that exceeds the interocular distance. For convenience, an example configuration is shown here where the projectors are arranged at the equivalent interocular distance.

[0042] The installation interval between each of the projectors 20A to 20C is selected to be equivalent to this interocular distance, and the projection angle of the adjacent projectors 20A to 20C relative to the diffusion screen 12 is then approximately 6°. Therefore, if the projection distance to the diffusion screen 12 is approximately 600 mm horizontally, the installation interval (width) between the adjacent projectors 20 will be approximately 50 mm.

[0043] Therefore, in this example, the width of the projector bodies 40A to 40C is smaller than the interval between adjacent projectors, and projectors with a field angle that allows the image to be projected over the entire screen surface are used. As mentioned above, when the interval between the projection angles is about 6°, the interval T between adjacent projectors (Fig. 9) is about 5 to 7 cm, so a relatively small, vertical projector with a width (horizontal width) of about 50 mm is used. The projected image is projected in a fairly bright room. illuminationIt is preferable that the brightness of the projectors 20A to 20C is such that they can be used without turning off the light, and therefore the light source brightness of the projectors 20A to 20C is preferably 500 lumens (lm) or more.

[0044] An example of a projector array 20 configured using three projectors is shown in Fig. 7. Projector 20A is installed in the center, and projectors 20B and 20C are installed on either side of it at a predetermined distance.

[0045] The projector array 20 is attached and fixed to a base 50 having a U-shaped cross section as shown in Fig. 8. An upper base 51 of the base 50 has a slit 54 extending in the longitudinal direction as shown in Fig. 7, and by threading fastening screws 60A to 60C into bottom screw holes 44 (44A) of the projector main bodies 40A to 40C through this slit 54 as shown in Figs. 8 and 9, the three projectors 20A to 20C are fixed while maintaining the above-mentioned attachment intervals (see Fig. 9). In Fig. 8, 46 (46A to 46C) indicate projection lenses.

[0046] As shown in FIG. 7, the projector 20A is set so that the projection centers Qo, Qa, and Qb of the respective projectors 20A to 20C face the center P of the diffusion screen 12, and the mounting angles and mounting intervals of the left and right projectors 20B and 20C are adjusted with the central projector 20A as the reference. The use of the slits 54 makes it easy to adjust the mounting angles and mounting intervals. Necessary auxiliary lines, such as indicator lines indicating the mounting positions and mounting directions of the projectors 20A to 20C, can also be engraved on the top surface of the upper base 51. This simplifies the setup of the device on site.

[0047] 8, the lower base 52 of the base 50 is used as a base for attaching a tripod 70. A mounting screw 76 is provided on a platform 72 attached to the tripod 70, and the mounting screw 76 can be used to screw into the screw hole 56 of the lower base 52, thereby fixing the projector array 20 to the tripod 70. The projection position of the entire projector array 20 is adjusted using adjustment knobs (adjustment screws) 80a and 80b attached to the tripod 70.

[0048] In the above description, an example was given in which an observer watches an image projected on the diffusion screen 12 from behind the projector array 20, but when arranging observers so that they are adjacent to each other at 90° angles to the same diffusion screen 12, two projector arrays 20 are installed at 90° intervals, and in this case it is preferable to use an isotropic diffusion layer 14 that has the same co-diffusion angle in the horizontal and vertical directions as the diffusion screen 12. This is because isotropic diffusion results in omnidirectional diffusion, with the same diffusion in both the horizontal and vertical directions.

[0049] By arranging three of the above-described projector arrays 20 in multiple directions around the diffusion screen 12, for example, at 120° angular intervals around a round table as shown in Figure 10, and projecting images from each of the projector arrays 20, 80, and 90 onto the same diffusion screen 12 in a superimposed manner, it becomes possible to observe images (the same or different images) limited to the observer's surroundings, or to display a variety of information, including information in different languages. In this case, an isotropic diffuser panel is used. By projecting multiple images from multiple directions in a superimposed manner onto the diffusion screen 12 in this way, each image can be observed from multiple directions without interference from the other images.

[0050] When viewers are positioned facing each other across a diffusion screen, an anisotropic diffusion layer with different diffusion angles in the horizontal and vertical directions can be used as the diffusion layer 14. While the horizontal diffusion angle must take into account the brightness characteristics described above, increasing the vertical (up-down) diffusion angle widens the viewing zone in the vertical direction. Furthermore, the vertical diffusion angle can be reduced to reduce the effects of external light reflections and increase the brightness of the image.

[0051] 11, when the diffusion screen 12 is hung on a wall 100 or the like, it is preferable to use an anisotropic diffusion layer, which has a wider diffusion range in the vertical direction (vertical direction) than in the horizontal direction, as the diffusion layer 14. By increasing the diffusion angle in the vertical direction (vertical direction), the viewing zone in the vertical direction is expanded, and a wide range of viewing point heights due to differences in observer heights can be covered.

[0052] The present invention is not limited to the above-described embodiment, and modifications are possible within the scope of the invention. [Industrial Applicability]

[0053] The above-described embodiment is easy to install and has high brightness, and can be applied, for example, to video display devices for real-time communication and video display devices for entertainment and amusement, and can be widely used as a communication tool in the field of communication. [Explanation of symbols]

[0054] 10...Display device 20(20A~20C)...Projection device 20, 80, 90... projector array 12. Retroreflective diffusion screen (diffusion screen) 13. Retroreflective material 14. Transmissive diffusion layer (diffusion layer) 70...Tripod 72... Pan head 50···Pedestal 54 Slit

Claims

1. The present invention comprises a retroreflective diffusion screen having a retroreflective material and a transmissive diffusion layer, and two or more projection devices that project an image onto the retroreflective diffusion screen, wherein a portion of the diffused light among the reflected light of the image projected from one of the adjacent projection devices is projected so as to overlap with a portion of the diffused light among the reflected light of the image projected from the other projection device adjacent to the one of the projection devices, and The reach range of the reflected light from the adjacent projectors after being reflected by the retroreflective diffusion screen and diffused is such that, when the rear of the projector is set as an observation position, there are reach areas of the diffused light that overlap each other at this observation position. A display device characterized by:

2. (delete)

3. 2. The display device according to claim 1, wherein adjacent overlapping diffused light arrival areas at an observation position behind the projection device have equal horizontal widths on a distribution map of the luminance characteristics of the projection device.

4. 4. The display device according to claim 1, wherein the reach areas of the overlapping diffused light at the observation position behind the projection device are areas that are symmetrical on a distribution chart of the brightness characteristics of the projection device, with a central axis being a perpendicular line to the horizontal axis of the distribution chart that passes through the point where adjacent brightness levels intersect, and the widths of the areas of adjacent brightness levels are divided equally in the horizontal direction with the perpendicular line as the central axis.

5. 5. The display device according to claim 1, 3 or 4, wherein a plurality of projection devices are arranged in a plurality of directions on either side of the retroreflective diffusion screen, and images from a plurality of directions are projected onto the retroreflective diffusion screen in a superimposed manner, so that each image can be observed independently from each of the plurality of directions.

Images