Spatial floating image display system

Abstract

To suitably display an image to the outside of a space, and contribute to "3: Good Health and Well-Being", "9: Industry, Innovation and Infrastructure", "11: Sustainable Cities and Communities" of the Sustainable Development Goals.SOLUTION: A spatial floating image display system comprises: a display panel for displaying an image; a light source device for the display panel; and a retroreflective member that reflects image light from the display panel and displays, in the air, a real spatial floating image formed by the reflected light. The retroreflective member includes a phase difference plate, and a phase difference plate having inverse wavelength dispersion is bonded on the image light incident surface side of the retroreflective member.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a spatial floating image display system.

Background Art

[0002] As a spatial floating image display system, a display method in which a video display device directly displays an image toward the outside and a spatial screen is already known. Further, for a retroreflective member that displays a spatial image, for example, it is disclosed in Patent Document 1. Furthermore, for example, it is disclosed in Patent Document 2.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] As a spatial floating image display system, a display method in which a video display device directly displays an image toward the outside and a spatial screen is already known. However, in the above-described conventional spatial floating image device, optimization of the design including the light source with respect to the luminance and chrominance of the spatial floating image has not been considered.

[0005] An object of the present invention is to provide a technique capable of performing a spatial floating image display with high visibility (apparent resolution and contrast) and high color reproducibility in a spatial floating image display system or a spatial floating image display device.

Means for Solving the Problems

[0006] In order to solve the above problems, for example, the configuration described in the claims is adopted. This application includes a plurality of means for solving the above problems, and as an example thereof, a spatial floating image display device is given below. A spatial floating image display system as an example of this application includes a display panel for displaying an image, a light source device for the display panel, and a retroreflective member that reflects the image light from the display panel and displays a real image of a spatial floating image in the air by the reflected light. The retroreflective member includes a retardation plate, and a retardation plate having inverse wavelength dispersion is bonded to the image light incident surface side of the retroreflective member.

Advantages of the Invention

[0007] According to the present invention, in a spatial floating image display system, in addition to the visibility (apparent resolution and contrast) that has been recognized as a conventional problem, a high-quality image display capable of enhancing the color reproducibility of the displayed spatial floating image can be realized. A spatial floating image display device can be realized. Problems, configurations, and effects other than the above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0008]

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Best Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the content of the embodiments (hereinafter also referred to as "the present disclosure") described below. The present invention also extends to the scope of the technical idea described in the spirit of the invention or the scope of the claims or equivalents thereof. Also, the configurations of the embodiments (examples) described below are merely illustrative, and various changes and modifications can be made by those skilled in the art within the scope of the technical idea disclosed in this specification.

[0010] Also, in the drawings for explaining the present invention, those having the same or similar functions are given the same reference numerals, and while different names may be used as appropriate, repeated explanations of functions and the like may be omitted. Note that in the following description of the embodiments, a floating image in space is expressed by the term "space-floating image". Instead of this term, it may be expressed as "aerial image", "spatial image", "aerial floating image", "spatial floating optical image of the display image", "aerial floating optical image of the display image", etc. The term "space-floating image" mainly used in the description of the embodiments is used as a representative example of these terms.

[0011] The present disclosure relates to a display system capable of transmitting an image formed by image light from a large-area image light source through a transparent member that partitions a space such as the glass of a show window, and displaying it as a floating image in the interior or exterior of a store (space). The present disclosure also relates to a large-scale digital signage system configured using a plurality of such display systems.

[0012] According to the following embodiments, for example, a high-resolution image can be displayed in a floating state on the glass surface of a show window or on a light-transmissive plate material. At this time, by reducing the divergence angle of the emitted image light, that is, making it an acute angle, and further aligning it with a specific polarization, only regular reflected light can be efficiently reflected by the retroreflective member.

[0013] In addition, by setting the transmittance or reflectance of the light source device, the liquid crystal display panel for image display, and the retroreflective member within a predetermined range, controlling the divergence angle of the light beam incident from the light source device on the liquid crystal display panel, and adjusting the wavelength of the image light beam emitted from the liquid crystal display panel and reflected by the retroreflective member, the color reproducibility of the entire system is improved. For this reason, the light utilization efficiency is high, and it is possible to improve the color reproducibility of the floating image in space, which has been a new problem in the conventional retroreflective method, and obtain a clear floating image in space.

[0014] In addition, an apparatus including a light source of the present disclosure and an optical system can provide a novel and highly usable floating image display system capable of significantly reducing power consumption.

[0015] On the other hand, in a conventional floating image display system, an organic EL panel or a liquid crystal display panel (liquid crystal panel or display panel) is combined with a retroreflective member as a high-resolution color display image source. On the surface of the first retroreflective member 2 used in a conventional floating image display device according to a technique that uses a liquid crystal panel capable of using image light of a specific polarization as an image display element, a reflecting surface formed of the polyhedron shown in FIG. 1B is formed.

[0016] Therefore, in the case of video light that diffuses at a wide angle, as shown in FIG. 1A, in addition to the floating image 220 (R1) formed by the regularly reflected light, multiple ghost images are generated. Since the shape of the reflecting member 2' shown in FIG. 1B is a hexahedron, six ghost images including the ghost images shown by reference numerals g1 and g2 are generated by the video light incident obliquely, deteriorating the image quality of the spatially floating video. In addition, the same spatially floating video, which is a ghost image, is viewed by people other than the viewer, posing a major problem from the perspective of security.

[0017] <Reflective retroreflective member with high color reproducibility> The cross-sectional structure of the retroreflective member 2 is shown in FIG. 1C. The retroreflective member 2 is composed of a reflective layer 2a, a transmissive substrate 2b, a reflecting surface 2c, and a λ / 4 plate 2d which is a retardation plate having an inverse wavelength dispersion characteristic. The retroreflective member is configured such that, in order from the video light incident surface side of the retroreflective member, there are a retardation plate 2d having an inverse wavelength dispersion characteristic, a transmissive substrate 2b, a reflective layer 2a, a transmissive substrate 2b, and a reflecting surface 2c. The retardation plate may be made of a polycarbonate material. The transmissive substrate 2b sandwiches a member having a refractive index close to that of the reflective layer 2a to obtain the required mechanical strength. The λ / 4 plate 2d is disposed on the video light incident surface, and the video light is reflected by the reflecting surface 2c and reflected twice by the retroreflective member to form retroreflected light. That is, the light incident on the retroreflective member 2 is incident on the retardation plate 2d having an inverse wavelength dispersion characteristic, passes through the transmissive substrate 2b and the reflective layer 2a, is reflected by the reflecting surface 2c, passes through the transmissive substrate 2b and the reflective layer 2a, and is incident on the retardation plate 2d again. At this time, most of the light incident on the reflective layer 2a passes through, but there is also some light that is reflected. Therefore, for example, when the light incident on the retroreflective member 2 is S-polarized light, the light emitted from the retroreflective member 2 is emitted as P-polarized light. At this time, the λ / 4 plate, which is the retardation plate used, is obtained by stretching a polycarbonate substrate to a desired thickness. At this time, the thickness of the stretched substrate is determined based on 137.5 nm, which is 1 / 4 of 550 nm where the specific sensitivity is high. The inventors selected the λ / 4 plate using color reproducibility as a new evaluation index.

[0018] Figure 2 is a characteristic diagram showing the characteristics of a typical commercially available λ / 4 plate. The color reproducibility of the spatial floating image was evaluated using samples with different partial dispersions based on light of 550 nm. For a λ / 4 plate with normal positive wavelength dispersion obtained by stretching a normal polycarbonate substrate with respect to the ideal straight line of partial dispersion, the phase correction amount is insufficient for light in the blue region of 470 nm or less, and the efficiency of polarization conversion is significantly reduced. As a result, when a white spatial floating image was displayed as the spatial floating image 220 shown in Fig. 1, it became yellowish white.

[0019] It was found that the color temperature of this white floating image also decreased significantly with respect to the color temperature of the LED light source. Next, even when a λ / 4 plate having a flat wavelength dispersion shown in Fig. 2 was used, since the phase correction amount was insufficient for light in the blue region of 470 nm or less, when a white spatial floating image was displayed, it became yellowish white. Further, as shown in Fig. 2, the same evaluation was also performed on two types of λ / 4 plates (characteristics (a) and (b)) having an inverse wavelength dispersion characteristic showing characteristics close to the ideal straight line of the wavelength dispersion characteristic in the wavelength region shorter than the reference wavelength of 550 nm.

[0020] The light source used in the light source device of the present invention shown in Figs. 3 and 4 is configured to emit white light by exciting a yellow phosphor with blue LED as excitation light from a surface-emitting white LED. Fig. 5 shows the emission spectrum.

[0021] In order to raise the color temperature of white light with a peak wavelength of 450 nm or less in the blue light among the light source light from the surface-emitting white LED to a high region, among the samples of characteristics (a) and (b) having an inverse wavelength dispersion characteristic in the blue-green and blue regions, the chromaticity of the white-displayed spatial floating image is moved in the direction of higher color temperature, and the characteristic that enables a more vivid white display is that the wavelength dispersion on the shorter wavelength side than the peak wavelength of 450 nm in the blue region of the light source light of the white LED is small, and the sample of characteristic (a) showed better performance. Also, since the wavelength dispersion on the long wavelength side is also close to the ideal curve, the color development of the red video light was improved.

[0022] From these results, the priority for selecting the λ / 4 plate 2d disposed on the front surface of the retroreflective member used in the spatial floating image display device whose cross-sectional structure is shown in FIG. 1C is as follows: (1) the wavelength dispersion is closer to an ideal straight line; (2) it is more effective that the wavelength dispersion in the blue region in particular is smaller than the ideal straight line; (3) furthermore, the color reproducibility of the entire system is improved. For this purpose, it is better to make the wavelength dispersion in the red region and the long wavelength region of 650 nm or more closer to the ideal straight line.

[0023] <Configuration example of the first retroreflective optical system forming the spatial floating image display system> Returning to FIG. 1 again, it is a diagram showing an example of the form of the retroreflective optical system used to realize the spatial floating image display system of the present disclosure. Further, FIG. 1 is a diagram for explaining the overall configuration of the spatial floating image display system in the present embodiment.

[0024] Referring to FIG. 1, for example, according to the spatial floating display system (hereinafter also referred to as "this system") of the present disclosure, when the spatial floating image display system is placed on a table for a viewer of the spatial floating image, the spatial floating image will be viewed downward. At this time, the imaging position (angle) of the spatial floating image is determined by the angle formed by the display surface of the liquid crystal display panel 11, the reflective polarizing plate 101 having a function as a beam splitter that reflects video light of a specific polarization, and the arrangement of the retroreflective member 2. The position where the spatial floating image is formed is imaged at a position symmetric to the surface of the retroreflective member 2 with the reflective polarizing plate 101 as the symmetry plane.

[0025] In addition to the focus performance, brightness, and lightness, the image quality of the above-described spatial floating image, the expansion of the color reproduction range will become a major weapon for differentiation from other companies in the future. The inventors reviewed the performance of the components regarding specific technical means for expanding the color reproducibility of the aerial floating image obtained by using a reflective retroreflective member with a liquid crystal panel as the video source.

[0026] In the spatial floating image display system of the present disclosure shown in FIG. 1, in order to reduce the generation of ghost images (indicated by g1 and g2 in the figure), the light source device 13 of the liquid crystal display panel 11 has a narrow divergence angle directivity characteristic and reduces diffused light other than regular light that retrorefracts, suppressing the generation of ghost images. Further, a video light control sheet 12 for controlling the diffusion characteristic of video light is provided on or in the vicinity of the light emitting surface of the liquid crystal display panel 11. As a result, the generation of ghost images can be significantly reduced.

[0027] The video light 5001 of a specific polarization wave from the video display device 1 is reflected by a reflective polarizing plate 101 acting as a polarization beam splitter provided on the light incident surface of the transparent plate 100, and the reflected light 5002 is incident on the retroreflective member 2. A λ / 4 plate 2d is provided on the surface of the retroreflective member 2 as a retardation plate, and since the retroreflected light passes through twice and equivalently acts as a λ / 2 plate, the polarization is converted, and the retroreflected light 5003 forms a spatial floating image at a position with the aforementioned reflective polarizing plate 101 as the axis of symmetry. In order to prevent external light from entering and incident on the retroreflective member, an absorption type polarizing plate 102 that transmits the polarized video light may be provided between the transparent plate 100 and the reflective polarizing plate 101.

[0028] <Absorption type polarizing plate> The spectral transmittance of a general absorption type polarizing plate provided on the above-mentioned transparent plate 100 is shown in FIG. 8. Since the transmittance in the blue-green wavelength region of 500 nm or less is lower than the transmittance in the long wavelength region of 550 nm or more, the absorption in the blue region of the emission spectrum of the white LED shown in FIG. 5 is large, and the color temperature of white shifts to the low temperature side along the blackbody locus in the chromaticity diagram shown in FIG. 10, and the color reproduction range becomes narrow. Further, the spectral transmittance of the polarizing plates bonded to the light source side and the video light emitting surface side of the liquid crystal display panel 11 is shown in FIG. 8. The transmittance of the transmission axis is the same as that of the above-mentioned general absorption type polarizing plate. Since the transmittance in the blue-green wavelength region of 500 nm or less is lower than the transmittance in the long wavelength region of 550 nm or more, the absorption in the blue region of the emission spectrum of the white LED shown in FIG. 5 is large, and the color temperature of white is shifted to the low temperature side along the blackbody locus in the chromaticity diagram shown in FIG. 10.

[0029] FIG. 9 shows the structure of a general absorption-type polarizing plate. By stretching a PVA film in a specific direction and dyeing it with a dye, the polarization characteristics with respect to a specific polarization wave are controlled. Since this PVA (Polyvinyl alcohol) has high hydrophilicity, it is configured to suppress moisture absorption by sandwiching both sides with TAC (Tri acetyl cellulose) films. The dye that controls the polarization characteristics increases the absorption at short wavelengths of 500 nm or less when improving the polarization degree (transmission axis transmittance / absorption axis transmittance).

[0030] In the optical system of the spatial floating image display system of the present invention, an absorption-type polarizing sheet 102 that selectively transmits video light of a specific polarization wave provided on a transparency plate 100 provided in a window through which video light for forming a spatial floating image passes to the outside of the set has the property of transmitting video light of a specific polarization wave. Therefore, the video light of the specific polarization wave passes through the absorption-type polarizing sheet 102. A real-space floating video image 220 is formed at a symmetric position with respect to the retroreflective member 2 by the transmitted video light.

[0031] With the spatial floating image display device of the present disclosure, the light that forms the obtained aerial floating video image 220 is a set of light rays that converge from the retroreflective member 2 to the optical image of the aerial floating video image 220, and these light rays continue straight even after passing through the optical image of the aerial floating video image 220. Therefore, the aerial floating video image 220 is an image with high directivity, unlike the diffused video light formed on a screen by a general projector or the like.

[0032] FIG. 11 shows a chromaticity diagram showing the chromaticity at the time of white display of the spatial floating image display device. FIG. 12 shows a chromaticity diagram in which MacAdam's color discrimination ellipses are superimposed on the chromaticity diagram showing the chromaticity at the time of white display of the spatial floating image display device. The sensitivity for each coordinate region with respect to the chromaticity change by human visual observation (CIE XY chromaticity coordinate system) is represented by MacAdam's isochromatic ellipses showing the region recognized as the same color by the amount of deviation from the center point of the ellipse on the XY chromaticity coordinates shown in FIGS. 11 and 12. Since the sensitivity to recognize subtle chromaticity changes increases as the color temperature increases, sufficient attention is required when using vivid white as the base tone in order to expand the color reproduction range of the spatial floating image in the future.

[0033] As described above, in the optical system using the liquid crystal display panel and the retroreflective member, the spectral transmittance in the blue-green wavelength region of 500 nm or less of the reflective polarizing plate, the transmissive polarizing plate, and the transmissive polarizing plate bonded to the liquid crystal display panel used is lower than that for the wavelengths in the green-red region. Therefore, in order to ensure the reproducibility of white, it is essential to use a λ / 4 plate bonded to the surface of the retroreflective member used in the embodiments of the present invention, which has inverse wavelength dispersion characteristics.

[0034] Further, in the configuration of the embodiment of the present invention shown in FIG. 1, when the user views from the direction shown in the figure, the floating image 220 in the air is viewed as a bright image. However, when other persons view from the vertical and front-back directions of the paper surface, the floating image 220 in the air cannot be viewed as an image at all. This characteristic is very suitable when employed in a system for displaying images that require high security or highly confidential images that need to be concealed from the person facing the user.

[0035] Note that depending on the performance of the retroreflective member 2, the polarization axes of the image light after reflection may become uneven. In this case, some of the image light with uneven polarization axes is absorbed by the absorption-type polarizing sheet 102 described above. Therefore, unnecessary reflected light does not occur in the retroreflective optical system, and it is possible to prevent or suppress a deterioration in the image quality of the floating image in space.

[0036] Also, in the spatial floating image display device using the retroreflective optical system of the present disclosure, even when the viewer peeks at the spatial floating image, the display screen of the image display device 1 is shielded by the reflection surface of the retroreflective member 2. Therefore, in this spatial floating image display device, compared with the case where the image display device 1 and the retroreflective member face each other, since the image display device 1 is arranged on the viewing side, the display image is directly difficult to view.

[0037] Furthermore, since the reflectance of the reflection member such as the retroreflective member for the video light from the liquid crystal display panel 11 can be increased in principle, it is preferable to use S-polarized light. However, when the viewer uses polarized sunglasses, the floating image in the air is reflected or absorbed by the polarized sunglasses. Therefore, as a countermeasure, a depolarizing element 103 may be provided to optically convert a part of the video light of a specific polarization into the other polarization and pseudo-convert it into natural light. As a result, even when the viewer uses polarized sunglasses, a good spatial floating image can be viewed. When optically joined by the transparent plate 100 and the adhesive, no light reflection surface is generated and the image quality of the spatial floating image is not impaired.

[0038] Examples of commercially available depolarizing elements include Cosmo Shine SRF (manufactured by Toyobo Co., Ltd.) and depolarizing adhesive (manufactured by Nagase Sangyo Co., Ltd.). In the case of Cosmo Shine SRF (manufactured by Toyobo Co., Ltd.), by attaching an adhesive on the image display device, the reflection at the interface can be reduced and the luminance can be improved. In the case of the depolarizing adhesive, it is used by bonding a colorless transparent plate and the image display device via the depolarizing adhesive. In this embodiment, as described above, the video display device 1 includes a light source device 13 that generates light of a specific polarization having a diffusion characteristic at an included angle with the liquid crystal display panel 11.

[0039] <Video Light Control Sheet> In the above-described video display device 1, in order to make the diffusion characteristics in the screen vertical direction and the screen horizontal direction different, a video light control sheet is provided on the video light emission surface of the liquid crystal display panel 11. The video light control sheet 12 adjusts the emission direction and divergence angle of the video light beam emitted from the liquid crystal display panel 11. As this video light control sheet, for example, a viewing angle control film (VCF) of Shin-Etsu Polymer Co., Ltd. is suitable. Since its structure is a sandwich structure in which transparent silicon and black silicon are alternately arranged and a synthetic resin is arranged on the light input / output surface, the same effect as that of the external light control film of this embodiment can be expected. At this time, since the transparent silicon and black silicon extending in a predetermined direction are alternately arranged in the viewing angle control film (VCF), by tilting the extending direction of the transparent silicon and black silicon of the video light control sheet 12 with respect to the vertical direction in the pixel arrangement direction of the liquid crystal display panel 11, it is preferable to arrange it so as to reduce moiré generated at the pitch of the pixels and the external light control film.

[0040] (1) In order to reduce the vertical stripes generated by the transmissive portion and the light absorption portion of the video light control sheet and the moiré generated by the pixel arrangement of the liquid crystal panel 11, it is preferable to arrange the above-mentioned vertical stripes and pixel arrangement with an inclination. Further, (2) when the pixel size of the liquid crystal panel 11 is A and the pitch of the vertical stripes of the video light control sheet 12 is B, selecting this ratio (B / A) outside an integer multiple has a further effect of reducing moiré.

[0041] One pixel of the liquid crystal panel 11 is composed of three pixels of RGB arranged in parallel and is generally square. Therefore, it is impossible to suppress the generation of moiré described above over the entire screen. For this reason, as an arrangement having the inclination shown in (1), it was experimentally determined that it should be optimized within the range of 5 degrees to 25 degrees so that the generation position of moiré can be intentionally shifted to a place where a floating image is not displayed. Although the liquid crystal panel has been described as a material for reducing moiré, the moiré generated between the retroreflective member 2 and the video light control sheet 12 is generated because both are linear structures. By optimally tilting the video light control sheet with respect to the pixel arrangement of the liquid crystal panel, it is possible to reduce large-scale moiré with a low frequency that can be visually recognized.

[0042] As shown in Fig. 1, the image light control sheet 12 is arranged on the image light emitting surface of the liquid crystal panel 11 and adhesively fixed to the image light emitting surface of the liquid crystal panel 11 by an adhesive material. Further, the diffusion angle and diffusion direction of the image light beam diffused from the spatially floating image are adjusted by the diffusion characteristics of the image light control sheet 12 and the diffusion characteristics of the light source device 13. The diffusion characteristics of the image light control sheet 12 mean that since transparent silicon and black silicon extending in a predetermined direction are alternately arranged, by tilting the extending direction of the transparent silicon and black silicon of the image light control sheet 12 with respect to the vertical direction in the arrangement direction of the pixels of the liquid crystal display panel 11, moiré generated at the pitch of the pixels and the external light control film is reduced. Further, the diffusion characteristics of the light source device 13 mean that by configuring the reflecting surface 307 provided on the reflection type light guide 306 shown in Fig. 13B(2) to have a plurality of inclinations on one surface, the reflected light is adjusted with higher precision. In the case of the reflecting surface, as a configuration having a plurality of inclinations on one surface, the region used as the reflecting surface may be a plurality of surfaces or multiple surfaces or a curved surface. As shown in Fig. 13B, for the reflecting surface 307, the parallel light beam φ5 (R7 to R10) from the reflector 300 is reflected by a plurality of surfaces (P7 to P10) with different inclinations in its traveling direction and heads toward the corresponding liquid crystal panel portions.

[0043] <Performance of Liquid Crystal Panel> Incidentally, in a general TFT (Thin Film Transister) liquid crystal panel, the luminance and contrast performance differ depending on the light emission direction and the characteristics of the liquid crystal and polarizing plate. In the evaluation in the measurement environment shown in Fig. 22, the characteristics of the luminance and viewing angle in the short side (vertical) direction of the panel are excellent at an angle slightly deviated from the emission angle perpendicular to the panel surface (emission angle ˚) (in this embodiment, +5˚) as shown in Fig. 24. The reason for this is that in the short side (vertical) direction of the liquid crystal panel, the characteristic of twisting light does not become 0˚ when the applied voltage is maximum.

[0044] On the other hand, the contrast performance in the short side (vertical) direction of the panel is excellent in the range of -15˚ to +15˚ as shown in Fig. 26. When combined with the luminance characteristics, the best characteristics can be obtained by using in the range of ±10˚ centered on 5˚.

[0045] Also, as shown in Fig. 23, the characteristics of luminance and viewing angle in the longitudinal (left - right) direction of the panel are excellent at an emission angle perpendicular to the panel surface (emission angle of 0 degrees). The reason is that in the longitudinal direction (left - right direction) of the liquid crystal panel, the characteristic of twisting light becomes 0 degrees when the applied voltage is maximum.

[0046] Similarly, as shown in Fig. 25, the contrast performance in the longitudinal (left - right) direction of the panel is excellent in the range from - 5 degrees to - 10 degrees. When combined with the luminance characteristics, the best characteristics can be obtained in the range of ±5 degrees centered around - 5 degrees. Therefore, the emission angle of the video light emitted from the liquid crystal panel is such that light is incident on the liquid crystal panel from the direction where the best characteristics can be obtained by the light beam direction conversion means provided in the light guide of the light source device 13 described above, and the light is modulated by the video signal, which will improve the image quality and performance of the video display device 1.

[0047] In order to make the most of the luminance and contrast characteristics of the liquid crystal panel as a video display element, by setting the incident light from the light source to the liquid crystal panel within the above - mentioned range, the video quality of the floating video in space can be improved.

[0048] <Method for Controlling Light Source Light> In this embodiment, in order to improve the utilization efficiency of the emitted light beam from the light source device 13 and significantly reduce the power consumption, in the video display device 1 configured to include the light source device 13 and the liquid crystal display panel 11, after the light is incident on the liquid crystal panel 11 from the light source device 13 at an incident angle that maximizes the characteristics of the liquid crystal panel 11, the video light beam modulated in luminance according to the video signal is emitted toward the retro - reflection member. At this time, in order to miniaturize the set volume of the floating video display system, it is desired to increase the degree of freedom in the arrangement of the liquid crystal panel 11 and the retro - reflection member. Further, in order to form the floating video at a desired position and ensure an optimal directivity after retro - reflection, the following technical means are used.

[0049] On the image display surface of the liquid crystal panel 11, as a light direction conversion panel, a transparent sheet made of optical components such as a linear Fresnel lens is provided to control the emission direction of the incident light beam to the retroreflective optical member while imparting high directivity, thereby determining the imaging position of the spatial floating image. According to this configuration, the image light from the image display device 1 can efficiently reach the observer with high directivity (straightness) like laser light. As a result, a high-quality floating image can be displayed with high resolution, and at the same time, the power consumption of the image display device 1 including the light source device 13 can be significantly reduced.

[0050] <Example 1 of the image display device> FIG. 17 shows another example of the specific configuration of the image display device 1. The light source device 13 in FIG. 17 is the same as the light source device in FIGS. 17 and the like. This light source device 13 is configured by housing an LED, a collimator, a composite diffusion block, a light guide, etc. in a case made of, for example, plastic, and a liquid crystal display panel 11 is attached to its upper surface. Also, on one side surface of the case of the light source device 13, LED (Light Emitting Diode) elements 14a, 14b which are semiconductor light sources and an LED substrate on which its control circuit is mounted are attached, and on the outer surface of the LED substrate, a heat sink which is a member for cooling the heat generated by the LED elements and the control circuit is attached (not shown).

[0051] Also, on the liquid crystal display panel frame attached to the upper surface of the case, the liquid crystal display panel 11 attached to the frame and, further, an FPC (Flexible Printed Circuits) (not shown) electrically connected to the liquid crystal display panel 11 are attached and configured. That is, the liquid crystal display panel 11 which is a liquid crystal display element, together with the LED elements 14a, 14b which are solid light sources, modulates the intensity of the transmitted light based on a control signal from a control circuit (not shown here) which constitutes an electronic device, thereby generating a display image.

[0052] <Example 1 of the light source device of Example 1 of the image display device> Next, the configuration of the optical system such as the light source device housed in the case will be described in detail with reference to FIGS. 17(a) and (b) together with FIG. 16. FIGS. 16 and 17 show the LEDs 14a and 14b that make up the light source 7, which are attached to the collimator 15 at predetermined positions. Note that each of these collimators 15 is formed of a light-transmissive resin such as acrylic. As shown in FIG. 17(b), the collimator 15 has a conical convex outer peripheral surface 156 obtained by rotating a parabolic cross-section, and a concave portion 153 having a convex portion (i.e., a convex lens surface) 157 formed at the central portion of its top (the side in contact with the LED substrate).

[0053] Also, at the central portion of the flat surface portion (the side opposite to the above-mentioned top) of the collimator 15, there is a convex lens surface (or it may be a concave lens surface recessed inward) 154 that protrudes outward. Note that the parabolic surface 156 that forms the conical outer peripheral surface of the collimator 15 is set within a range of angles that allows the light emitted from the LEDs 14a and 14b in the peripheral direction to be totally reflected inside it, or a reflecting surface is formed.

[0054] Also, the LEDs 14a and 14b are respectively arranged at predetermined positions on the surface of the substrate 102, which is their circuit board. This substrate 102 is arranged and fixed with respect to the collimator 15 such that the LEDs 14a or 14b on its surface are respectively located at the central portions of the concave portions 153.

[0055] According to such a configuration, among the light emitted from the LED 14a or 14b, particularly the light emitted upward (in the right direction of the figure) from the central portion thereof, is condensed by the two convex lens surfaces 157 and 154 forming the outer shape of the collimator 15 and becomes parallel light. Further, the light emitted from other portions in the peripheral direction is reflected by the parabolic surface forming the conical outer peripheral surface of the collimator 15 and, similarly, is condensed and becomes parallel light. In other words, according to the collimator 15 having a convex lens formed in its central portion and a parabolic surface formed in its peripheral portion, almost all of the light generated by the LED 14a or 14b can be taken out as parallel light, and it becomes possible to improve the utilization efficiency of the generated light.

[0056] Note that a polarization conversion element 21 is provided on the light emission side of the collimator 15. The polarization conversion element 21 may also be referred to as a polarization conversion member. As is clear from FIG. 17(a), this polarization conversion element 21 is formed by combining a columnar light-transmissive member having a parallelogram cross section (hereinafter, parallelogram column) and a columnar light-transmissive member having a triangular cross section (hereinafter, triangular column), and is configured by arranging a plurality of them in an array parallel to the plane orthogonal to the optical axis of the parallel light from the collimator 15. Further, a polarization beam splitter (hereinafter, abbreviated as "PBS film") 211 and a reflection film 212 are alternately provided at the interfaces between adjacent light-transmissive members arranged in this array, and a λ / 2 phase plate 213 is provided on the emission surface from which the light incident on the polarization conversion element 21 and transmitted through the PBS film 211 is emitted.

[0057] A rectangular composite diffusion block 16 shown also in FIG. 17(a) is further provided on the emission surface of this polarization conversion element 21. That is, the light emitted from the LED 14a or 14b becomes parallel light by the action of the collimator 15, enters the composite diffusion block 16, is diffused by the texture 161 on the emission side, and then reaches the light guide 17.

[0058] The light guide 17 is a member formed of a translucent resin such as acrylic into a rod shape with a substantially triangular cross section (see Fig. 17(b)). As is also clear from Fig. 4, the light guide light incident portion (surface) 171 facing the light emitting surface of the synthetic diffusion block 16 via the first diffusion plate 18a, the light guide light reflecting portion (surface) 172 forming an inclined surface, and the light guide light emitting portion (surface) 173 facing the liquid crystal display panel 11, which is a liquid crystal display element, via the second diffusion plate 18b.

[0059] As shown in Fig. 16, which is a partially enlarged view of the light guide light reflecting portion (surface) 172 of the light guide 17, a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a serrated shape. The reflecting surface 172a (the line segment rising to the upper right in the figure) forms an angle αn (n is a natural number, and in this example, for example, it is 1 to 130) with the horizontal plane indicated by the dashed-dotted line in the figure. As an example, here, αn is set to 43 degrees or less (however, 0 degrees or more).

[0060] The light guide incident portion (surface) 171 is formed in a curved convex shape inclined toward the light source side. According to this, the parallel light from the light emitting surface of the synthetic diffusion block 16 is diffused and incident via the first diffusion plate 18a, and as is clear from the figure, it reaches the light guide light reflecting portion (surface) 172 while being slightly bent (deflected) upward by the light guide incident portion (surface) 171, and is reflected here and reaches the liquid crystal display panel 11 provided on the upper light emitting surface of the figure.

[0061] According to the video display device 1 described in detail above, it is possible to further improve the light utilization efficiency and its uniform illumination characteristics, and at the same time, it is possible to manufacture in a small size and at low cost including the modularized light source device of the S polarized light wave. In the above description, the polarization conversion element 21 is described as being attached after the collimator 15, but the present invention is not limited thereto, and the same operation and effect can be obtained by providing it in the optical path reaching the liquid crystal display panel 11.

[0062] Note that in the light reflector section (surface) 172 of the light guide, a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a zigzag shape. The illumination light beam is totally reflected on each reflecting surface 172a and directed upward. Further, a sandwiching angle diffuser plate is provided in the light emitting section (surface) 173 of the light guide, and the light beam is incident on the light direction conversion panel 54 that adjusts the directivity characteristics to form a substantially parallel diffused light beam, and then enters the liquid crystal display panel 11 from an oblique direction. The emitted light of this video display device 1 is controlled in the emission direction by the light direction conversion panel 54 provided on the upper surface of the light source device 13. As a result, the emitted light from the liquid crystal display panel 11 is also controlled, and the light diffusion direction of the spatial floating video obtained by the spatial floating video display system using this video display device 1 is controlled. In this embodiment, the light direction conversion panel 54 is provided between the light guide emission surface 173 and the liquid crystal display panel 11, but the same effect can be obtained even if it is provided on the emission surface of the liquid crystal display panel 11.

[0063] The emitted light from the liquid crystal display panel 11 has mutually similar diffusion characteristics in the horizontal direction of the screen (the display direction corresponding to the X-axis of the graph in Fig. 20(A)) and the vertical direction of the screen (the display direction corresponding to the Y-axis of the graph in Fig. 20(B)), as shown by the plotted curves of "conventional characteristics (X direction)" in Fig. 20(A) and "conventional characteristics (Y direction)" in Fig. 20(B) for a device for general TV use.

[0064] In contrast, the diffusion characteristics of the emitted light beam from the liquid crystal display panel of this embodiment are such as shown by the plotted curves of "Example 1 (X direction)" in Fig. 20(A) and "Example 1 (Y direction)" in Fig. 20(B).

[0065] In one specific example, when the viewing angle at which the luminance becomes 50% of the luminance in the front view (angle 0 degrees) (the luminance is reduced to about half) is set to 13 degrees, it is about 1 / 5 of the diffusion characteristics (angle 62 degrees) of a device for general household TV use. Similarly, in an example where the viewing angles in the vertical direction are unevenly set for the upper side and the lower side, the reflection angle of the reflective light guide, the area of the reflecting surface, etc. are optimized so that the viewing angle on the upper side is suppressed (narrowed) to about 1 / 3 of the viewing angle on the lower side.

[0066] By setting the viewing angle and other parameters as described above, the amount of light of the video directed towards the user's viewing direction is significantly increased compared to conventional LCD TVs (substantially improved in terms of the brightness of the video), and the brightness of such video becomes 50 times or more.

[0067] Furthermore, when the viewing angle characteristics shown in "Example 2" of FIG. 20 are adopted, when the viewing angle at which the brightness becomes 50% of the brightness of the video obtained in the front view (angle 0 degrees) (the brightness is reduced to about half) is set to 5 degrees, it becomes an angle about 1 / 12 (narrow viewing angle) with respect to the diffusion characteristics (angle 62 degrees) of a general household TV device. Similarly, in an example where the viewing angle in the vertical direction is evenly set for the upper and lower sides, the reflection angle and the area of the reflecting surface of the reflective light guide are optimized so that such a vertical viewing angle is suppressed (narrowed) to about 1 / 12 compared to the conventional case.

[0068] By making such settings, the brightness (amount of light) of the video directed towards the viewing direction (the user's line of sight direction) is significantly improved compared to conventional LCD TVs, and the brightness of such video becomes 100 times or more.

[0069] As described above, by using the viewing angle as the included angle, the amount of light flux directed towards the viewing direction can be concentrated, so that the light utilization efficiency is significantly improved. As a result, even when using a liquid crystal display panel for general TV applications, by adjusting the light diffusion characteristics of the light source device, a significant improvement in brightness can be achieved with the same power consumption, and a video display device corresponding to a display system for a bright outdoor environment can be obtained.

[0070] When using a large liquid crystal display panel, the light around the screen is directed inward so that it heads toward the viewer when the viewer is facing the center of the screen, thereby improving the overall uniformity of the screen brightness. Figure 21 shows the convergence angles of the long side and the short side of the liquid crystal display panel with the distance L from the liquid crystal display panel to the viewer and the panel size of the video display device (screen ratio 16:10) as parameters. The upper figure assumes the case of viewing the video with the screen of the liquid crystal display panel in portrait orientation (hereinafter also referred to as "portrait use"). In this case, the convergence angle may be set according to the short side of the liquid crystal display panel (refer to the direction of arrow V in Fig. 20 as appropriate).

[0071] As a more specific example, as can be seen by referring to the plot graph in Fig. 21, for example, when viewing at a viewing distance of 0.8 m in portrait use of a 22" panel, by setting the convergence angle to 10 degrees, the video light from each corner (4 corners) of the screen can be effectively projected or output toward the viewer.

[0072] Similarly, when viewing in portrait use of a 15" panel at a viewing distance of 0.8 m, if the convergence angle is set to 7 degrees, the video light from the 4 corners of the screen can be effectively directed toward the viewer. As described above, by directing the video light around the screen according to the size of the liquid crystal display panel and whether it is in portrait or landscape use toward the viewer who is in the optimal position to view the center of the screen, the overall uniformity of the screen brightness can be improved.

[0073] As a basic configuration, as shown in Fig. 20 and the like described above, a light beam with a sandwiching angle and directivity characteristics is incident on the liquid crystal display panel 11 by a light source device, and the luminance is modulated according to the video signal, so that the video displayed on the screen of the liquid crystal display panel 11 and the spatially floating video obtained by reflecting with a retroreflective member are displayed outdoors or indoors through a transparent member 100.

[0074] Hereinafter, a plurality of examples of another example of the light source device will be described. Any of these other examples of the light source device may be adopted by replacing the light source device in the example of the video display device described above.

[0075] When using a large liquid crystal display panel, as described above, the light around the screen is directed inward so that when the viewer faces the center of the screen, it goes in the direction of the viewer, improving the overall screen brightness. On the other hand, binocular disparity occurs depending on whether the viewer views with the left or right eye. Figure 21 shows the convergence angles of the long side and short side of the liquid crystal display panel with respect to the positions of the left and right eyes, with the distance L from the liquid crystal display panel to the viewer and the panel size (screen ratio 16:10) of the video display device as parameters.

[0076] The smaller the panel size and the closer the viewing distance, the larger the convergence angle due to binocular vision by the left and right eyes. Especially when using a small panel of 7 inches or less, the convergence angle due to binocular disparity becomes an important requirement. For example, in the case of 7 inches or less, the light diffusion characteristics or directivity characteristics of the light source shown in Figure 19 are expanded or given directivity characteristics so that the video light is directed towards the optimal view of the system.

[0077] Furthermore, depending on the required specifications of the system, in order to obtain horizontal and vertical directivity characteristics and diffusion characteristics, it is necessary to optimally design the shape, surface roughness, inclination, etc. of the reflecting surface of the light guide body of the light source device 13 described above.

[0078] <Example 1 of Light Source Device> Next, with reference to Figure 3, another example of the light source device will be described. Figures 3(a) and (b) are diagrams in which a part of the liquid crystal display panel 11 and the diffusion plate 206 are omitted for explaining the light guide body 311.

[0079] Figure 3 shows a state in which the LEDs 14 constituting the light source are provided on the substrate 102. These LEDs 14 and the substrate 102 are attached to the reflector 300 at a predetermined position.

[0080] As shown in Figure 3(a), the LEDs 14 are arranged in a row in a direction parallel to the side (the short side in this example) of the liquid crystal display panel 11 on the side where the reflector 300 is arranged. In the illustrated example, corresponding to such an arrangement of the LEDs, the reflector 300 is arranged. Note that a plurality of reflectors 300 may be arranged.

[0081] In one specific example, each of the reflectors 300 is formed of a plastic material. As another example, the reflector 300 may be formed of a metal material or a glass material. However, since the plastic material is easier to mold, the plastic material is used in this embodiment.

[0082] As shown in FIG. 3(b), the inner surface (the right side in the figure) of the reflector 300 includes a reflecting surface (hereinafter may be referred to as a "parabolic surface") 305 having a shape obtained by cutting a parabolic surface by a meridian plane. The reflector 300 reflects the divergent light emitted from the LED 14 by the above-described reflecting surface 305 (parabolic surface) to convert it into substantially parallel light, and makes the converted light incident on the end face of the light guide 311. In addition to the aluminum reflection film, a plurality of metal films such as Ti and SiO are formed as an enhanced reflection film on the reflecting surface of the reflector 300 to increase the reflectance and reduce the dependence on the incident angle as shown in FIG. 6. In one specific example, the light guide 311 is a reflective light guide.

[0083] The reflecting surface of the reflector 300 has a shape asymmetric with respect to the optical axis of the light emitted from the LED 14. Further, the reflecting surface 321 of the reflector 300 is a parabolic surface as described above. By disposing the LED at the focus of such a parabolic surface, the light beam after reflection is converted into substantially parallel light.

[0084] Since the LED 14 is a surface light source, even if it is disposed at the focus of the parabolic surface, the divergent light from the LED cannot be completely converted into parallel light, but this does not affect the performance of the light source of the present invention. The LED 14 and the reflector 300 form a pair. In addition, in order to ensure a predetermined performance at the mounting accuracy of the LED 14 to the substrate 102 of ±40 μm, the number of LEDs mounted on the substrate should be at most 10 or less, and considering mass productivity, it is preferably suppressed to about 5.

[0085] Although the LED 14 and the reflector 300 are partially in proximity, heat can be dissipated into the space on the opening side of the reflector 300, so that the temperature rise of the LED can be reduced. For this reason, the plastic molded reflector 300 can be used. As a result, according to this reflector 300, the shape accuracy of the reflecting surface can be improved by more than 10 times compared with that of the reflector made of glass material, so that the light utilization efficiency can be improved.

[0086] On the other hand, as shown in FIG. 3(b), a reflecting surface is provided on the bottom surface 303 of the light guide 311. The light from the LED 14 is converted into a parallel light beam by the reflector 300, and then reflected by the reflecting surface and emitted toward the liquid crystal display panel 11 disposed opposite to the light guide 311. As shown in FIG. 3, the reflecting surface provided on the bottom surface 303 may have a plurality of surfaces with different inclinations in the traveling direction of the parallel light beam φ2 from the reflector 300. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300.

[0087] Also, as shown in FIG. 3, the shape of the reflecting surface provided on the bottom surface 303 may be a planar shape. Further, a diffusion plate 206 may be provided to more precisely control the diffusion characteristics of the light reflected by the reflecting surface provided on the bottom surface 303 of the light guide 311 facing the liquid crystal display panel 11.

[0088] This diffusion plate can refract the aforementioned reflected light once by the surface shape and surface roughness on both sides, and can precisely adjust the light quantity and emission direction of the light beam heading toward the liquid crystal display panel 11, so that the light quantity and emission direction of the incident light on the liquid crystal display panel 11 and the emitted light from the liquid crystal display panel 11 can also be controlled with high precision. For this reason, in a spatial video display system using a video display device using this light source, the diffusion direction and diffusion angle of the video light of the spatial floating video can be set to desired values. At this time, the reflective film provided on the reflecting surface is preferably designed to reduce the high reflectivity and the incident angle dependence of the reflectivity as shown in FIG. 7 by adding an antireflection film of Ti and SiO to the aluminum reflective film.

[0089] Since the above-mentioned matte aluminum reflective film has a lower reflectance in the blue-green wavelength region of 500 nm or less than that in the green-red region, improving the purity of white is also an important issue in the design of the antireflection film in order to reduce the incidence angle dependence of the reflectance and improve the color reproducibility.

[0090] As shown in FIG. 3, the LED 14 is soldered to the metallic substrate 102. Therefore, the heat generated by the LED can be dissipated into the air through the substrate. Further, the reflector 300 may be in contact with the substrate 102, or a space may be provided therebetween. When a space is provided, the reflector 300 is disposed by being adhered to the housing. By providing a space, the heat generated by the LED can be dissipated into the air, and the cooling effect is enhanced. As a result, the operating temperature of the LED can be reduced, so that the maintenance of the luminous efficiency and the extension of the service life can be realized.

[0091] <Example 2 of the light source device> Also in the light source device described above, by using the polarization conversion element 21, the light utilization efficiency can be improved by 1.8 times. Hereinafter, the configuration of the optical system related to this light source device will be described in detail with reference to FIGS. 13A, 13B, 13C, and 13D. Note that the illustration of the sub-reflector 308 is omitted in FIG. 13A.

[0092] FIGS. 13A, 13B, and 13C show a state in which the LED 14 constituting the light source is provided on the substrate 102, and these are configured by a unit 312 having a plurality of blocks with the reflector 300 and the LED 14 as a pair of blocks.

[0093] Among these, the base material 320 shown in FIG. 13A(2) is the base material of the substrate 102. Generally, since the metallic substrate 102 has heat, in order to insulate (heat-insulate) the heat of such a substrate 102, the base material 320 may be made of a plastic material or the like, or may be a metal member to enhance the heat dissipation property.

[0094] In addition, the reflecting surface of the reflector 300 may have a shape asymmetric with respect to the optical axis of the emitted light of the LED 14. The reason for this will be described with reference to FIG. 13A(2). In the present embodiment, the reflecting surface of the reflector 300 is a paraboloid, and the center of the light emitting surface of the LED, which is a surface light source, is arranged at the focal position of the paraboloid.

[0095] Also, due to the characteristics of the paraboloid, the light emitted from the four corners of the light emitting surface also becomes substantially parallel light beams, differing only in the emission direction. Therefore, even if the light emitting portion has an area, if the distance between the polarization conversion element arranged in the subsequent stage and the reflector 300 is short, the amount of light incident on the polarization conversion element 21 and the conversion efficiency are hardly affected.

[0096] In addition, even if the mounting position of the LED 14 is displaced in the XY plane with respect to the focal point of the corresponding reflector 300, an optical system can be realized that can reduce the decrease in light conversion efficiency for the reasons described above. Furthermore, even when the mounting position of the LED 14 varies in the Z-axis direction, the converted parallel light beam only moves in the ZX plane, and the mounting accuracy of the LED, which is a surface light source, can be significantly reduced. Although the reflector 300 having a reflecting surface obtained by meridionally cutting out a part of the paraboloid has been described in the present embodiment, an LED may be arranged on a part obtained by cutting out the entire paraboloid as the reflecting surface.

[0097] On the other hand, in the present embodiment, as shown in FIGS. 13A, 13B(1), and 13C, the divergent light from the LED 14 is reflected by the paraboloid 321 and converted into substantially parallel light, and then incident on the end face of the subsequent polarization conversion element 21, and the polarization conversion element 21 aligns it to a specific polarization state. With this characteristic configuration, in the present embodiment, the light utilization efficiency is 1.8 times that of the example of FIG. 3 described above, and a highly efficient light source can be realized.

[0098] At this time, the substantially parallel light obtained by reflecting the divergent light from the LED 14 by the paraboloid 321 is not all uniform. Therefore, by adjusting the angular distribution of the reflected light by the reflecting surface 307 having a plurality of inclinations, it is possible to make the light incident on the liquid crystal display panel 11 in a direction perpendicular to the liquid crystal display panel 11.

[0099] Here, in the example of this figure, it is arranged such that the direction of the light (main ray) entering the reflector from the LED and the direction of the light entering the liquid crystal display panel are substantially parallel. This arrangement is easy to arrange in terms of design, and it is preferable to arrange the heat source under the light source device because air can escape upward, reducing the temperature rise of the LED.

[0100] Also, as shown in FIG. 13B(1), in order to improve the capture rate of the divergent light from the LED14, the light beam that cannot be captured by the reflector 300 is reflected by the sub-reflector 308 provided on the light shielding plate 309 arranged above the reflector, and then reflected by the inclined surface of the lower sub-reflector 310 and incident on the effective area of the subsequent polarization conversion element 21 to further improve the light utilization efficiency. That is, in this embodiment, a part of the light reflected by the reflector 300 is reflected by the sub-reflector 308, and the light reflected by the sub-reflector 308 is reflected by the sub-reflector 310 in the direction toward the light guide 306.

[0101] The substantially parallel light beam aligned in a specific polarization by the polarization conversion element 21 is reflected toward the liquid crystal display panel 11 arranged to face the light guide 306 by the reflection shape provided on the surface of the reflection type light guide 306. At this time, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed according to the shape and arrangement of the reflector 300 described above, the reflection surface shape (cross-sectional shape) of the reflection type light guide, the inclination of the reflection surface, and the surface roughness.

[0102] As the reflection surface shape provided on the surface of the light guide 306, a plurality of reflection surfaces are arranged to face the light emitting surface of the polarization conversion element, and the inclination, area, height, and pitch of the reflection surface are optimized according to the distance from the polarization conversion element 21, so that, as described above, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 becomes a desired value.

[0103] As shown in Fig. 13B(2), the reflecting surface 307 provided on the reflective light guide can be configured to have a plurality of inclinations on one surface, so that the reflected light can be adjusted with higher precision. In the reflecting surface, as a configuration having a plurality of inclinations on one surface, the area used as the reflecting surface may be a plurality of surfaces, or multiple surfaces, or a curved surface. As shown in Fig. 13B(2), for the reflecting surface 307, the parallel light beams φ5 (R7 to R10) from the reflector 300 are reflected by a plurality of surfaces (P7 to P10) with different inclinations in their traveling directions and head toward the corresponding liquid crystal panel portions. Each of the plurality of surfaces with different inclinations may have a shape extending in a direction perpendicular to the traveling direction of the parallel light beam from the reflector 300. The light source light reflecting surface 307 of the light guide 306 has a configuration in which a plurality of reflecting surfaces are arranged in a direction perpendicular to the optical axis along which the light source light propagates, and the emission direction and the diffusion angle of the light source light incident on the liquid crystal display panel 11 are adjusted according to the inclination angles of the respective reflecting surfaces. That is, the reflecting surface 307 of the light guide 306 has a configuration in which a plurality of reflecting surfaces are arranged in a direction perpendicular to the optical axis of the light reflected by the reflecting surface of the reflector 300, and the emission direction and the diffusion angle of the light incident on the liquid crystal display panel 11 are adjusted according to the inclination angles of the respective reflecting surfaces.

[0104] Furthermore, due to the diffusion action of the diffusion plate 206, a more uniform light quantity distribution is realized. The light incident on the diffusion plate closer to the LED realizes a uniform light quantity distribution by changing the inclination of the reflecting surface. As a result, the light quantity and the emission direction of the light beam heading toward the liquid crystal display panel 11 can be adjusted with high precision. As a result, the light quantity and the emission direction of the light incident on the liquid crystal display panel 11 and the light emitted from the liquid crystal display panel 11 can also be controlled with high precision. Therefore, in the spatial floating image display system using the video display device using this light source, the diffusion direction and the diffusion angle of the image light of the spatial floating image can be set to desired values.

[0105] In this embodiment, the base material of the reflecting surface 307 may be a plastic material such as heat-resistant polycarbonate. Also, the angle of the reflecting surface 307 immediately after the emission of the λ / 2 plate 213 changes depending on the distance between the λ / 2 plate and the reflecting surface.

[0106] Also in this embodiment, although the LED 14 and the reflector 300 are in proximity in part, heat can be radiated into the space on the opening side of the reflector 300, and the temperature rise of the LED can be reduced. Further, the substrate 102 and the reflector 300 may be arranged upside down with respect to FIGS. 13A, 13B, and 13C.

[0107] However, when the substrate 102 is arranged upward, the substrate 102 comes close to the liquid crystal display panel 11, so the layout may become difficult. Therefore, as shown in the drawing, arranging the substrate 102 below the reflector 300 (the side far from the liquid crystal display panel 11) makes the configuration inside the apparatus simpler.

[0108] A light shielding plate 410 may be provided on the light incident surface of the polarization conversion element 21 so that light unnecessary for the subsequent optical system does not enter. With such a configuration, a light source device with suppressed temperature rise can be realized. In the polarizing plate provided on the light incident surface of the liquid crystal display panel 11, the temperature rise is reduced by absorption in the light beam with uniform polarization of the present invention, but when reflected by the reflection type light guide, the polarization direction rotates and part of the light is absorbed by the incident side polarizing plate. Further, the temperature of the liquid crystal display panel 11 also rises due to absorption by the liquid crystal itself and temperature rise caused by light incident on the electrode pattern, but there is sufficient space between the reflection surface of the reflection type light guide 306 and the liquid crystal display panel 11, enabling natural cooling.

[0109] FIG. 13D is a modified example of the light source device of FIGS. 13B(1) and 13C. FIG. 13D(1) illustrates a modified example by extracting a part of the light source device of FIG. 13B(1). Since the other configurations are the same as those of the light source device described above with reference to FIG. 13B(1), the illustration and repeated description are omitted.

[0110] First, in the example shown in FIG. 13D(1), the height of the concave portion 319 of the sub-reflector 310 is adjusted to be lower than that of the phosphor 114 so that the principal ray of the fluorescence output laterally (in the X-axis direction) from the phosphor 114 (refer to the straight line extending in the direction parallel to the X-axis in FIG. 13D(1)) passes through the concave portion 319 of the sub-reflector 310. Further, the height of the light shielding plate 410 in the Z-axis direction is adjusted to be lower with respect to the position of the phosphor 114 so that the principal ray of the fluorescence output laterally from the phosphor 114 enters the effective region of the polarization conversion element 21 without being blocked by the light shielding plate 410.

[0111] In addition, the reflecting surface of the convex portion of the unevenness at the top of the sub-reflector 310 reflects the light reflected by the sub-reflector 308 in order to guide the light reflected by the sub-reflector 308 to the light guide 306. Therefore, the height of the convex portion 318 of the sub-reflector 310 is adjusted so as to reflect the light reflected by the sub-reflector 308 and make it enter the effective region of the subsequent polarization conversion element 21, whereby the light utilization efficiency can be further improved.

[0112] Note that the sub-reflector 310 is arranged to extend in one direction as shown in FIG. 13A(2) and has an uneven shape. Further, at the top of the sub-reflector 310, unevenness having one or more concave portions 319 and convex portions 318 are arranged periodically along one direction. By adopting such an uneven shape, the principal ray of the fluorescence output laterally from the phosphor 114 can be configured to enter the effective region of the polarization conversion element 21.

[0113] In addition, the uneven shape of the sub-reflector 310 is arranged periodically at a pitch at which the concave portion 319 comes to the position where the LED 14 is located. That is, each of the phosphors 114 is arranged periodically along one direction corresponding to the pitch of the arrangement of the concave portions of the unevenness of the sub-reflector 310. When the phosphor 114 is provided in the LED 14, the phosphor 114 may be expressed as the light emitting portion of the light source.

[0114] Further, FIG. 13D(2) extracts a part of the light source device of FIG. 13C and illustrates a modified example thereof. Since the other configurations are the same as those of the light source device of FIG. 13C, illustration and repetitive description are omitted. As shown in FIG. 13D(2), the sub-reflector 310 may not be provided, but as in FIG. 13D(1), the height of the light shielding plate 410 in the Z-axis direction is adjusted so that the main light rays of the fluorescence output laterally from the phosphor 114 are not blocked by the light shielding body 410 and enter the effective area of the polarization conversion element 21 with respect to the position of the phosphor 114.

[0115] Regarding the light source devices of FIGS. 13A, 13B, 13C, and 13D, as shown in FIG. 13A(1), in order to prevent dust from entering the space between the reflecting surface of the reflective light guide 306 and the liquid crystal display panel 11, prevent stray light from being generated outside the light source device, and prevent stray light from entering from outside the light source device, a side wall 400 may be provided. When the side wall 400 is provided, it is arranged so as to sandwich the space between the light guide 306 and the diffusion plate 206.

[0116] The light emitting surface of the polarization conversion element 21 that emits the light polarization-converted by the polarization conversion element 21 faces the space surrounded by the side wall 400, the light guide 306, the diffusion plate 206, and the polarization conversion element 21. Further, among the inner surfaces of the side wall 400, the surface of the portion that covers the space from which light is output from the emission surface of the polarization conversion element 21 (the space on the right side from the emission surface of the polarization conversion element 21 in FIG. 13B(1)) from the side uses a reflective surface having a reflective film or the like. That is, the surface of the side wall 400 facing the above space is provided with a reflective region having a reflective film. By using the surface of this portion as the reflective surface among the inner surfaces of the side wall 400, the light reflected by the reflective surface can be reused as the light source light, and the luminance of the light source device can be improved.

[0117] Of the inner surfaces of the side wall 400, the surface of the portion that covers the polarization conversion element 21 from the side is a surface with low light reflectance (such as a black surface without a reflective film). This is because when reflected light is generated on the side surface of the polarization conversion element 21, light with an unexpected polarization state is generated, which causes stray light. In other words, by making the above-mentioned surface a surface with low light reflectance, the generation of stray light in the image and light with an unexpected polarization state can be prevented or suppressed. Also, a hole through which air passes may be formed in a part of the side wall 400 so as to improve the cooling effect.

[0118] Note that the light source devices in FIGS. 13A, 13B, 13C, and 13D have been described on the premise of a configuration using the polarization conversion element 21. However, these light source devices may be configured by omitting the polarization conversion element 21. In this case, the light source device can be provided at a lower cost.

[0119] <Example 3 of the light source device> Subsequently, the optical system configuration of a light source device using a reflective light guide 304 based on the light source device shown in Example 1 of the light source device will be described in detail with reference to FIGS. 14A(1), (2), (3), and 14B.

[0120] FIG. 14A shows a state in which the LEDs 14 constituting the light source are provided on the substrate 102. These are configured as a unit 328 having a plurality of blocks with the collimator 18 and the LED 14 as a pair of blocks. Since the collimator 18 of this embodiment is close to the LED 14, a glass material is adopted in consideration of heat resistance. The shape of the collimator 18 is the same as the shape described for the collimator 15 in FIG. 16. Also, by providing a light shielding plate 317 in the previous stage before the light enters the polarization conversion element 21, unnecessary light is prevented or suppressed from entering the subsequent optical system, and the temperature rise caused by the unnecessary light is reduced.

[0121] For other configurations and effects of the light source shown in FIG. 13A, since they are the same as those in FIGS. 13A, 13B, 13C, and 13D, repeated explanations are omitted. The light source device in FIG. 13A may be provided with side walls in the same manner as described in FIGS. 13A, 13B, and 13C. Since the configuration and effects of the side walls are as already described, repeated explanations are omitted.

[0122] FIG. 14B is a cross-sectional view of FIG. 14A(2). Regarding the configuration of the light source shown in FIG. 14B, it is common to a part of the structure of the light source in FIG. 17 and has already been described in FIG. 17, so repeated explanations are omitted.

[0123] <Example 4 of the light source device> Subsequently, the light source device in FIG. 4 is composed of a unit having a plurality of blocks with the collimator 18 and the LED 14 as a pair of blocks, which are used in the light source devices shown in FIGS. 14A and 14B. The optical system configuration of the light source device using the LED arranged at both ends of the back surface of the liquid crystal display panel 11 and the reflective light guide 504 will be described in detail with reference to FIGS. 4(a), (b), and (c).

[0124] FIG. 4 shows a state where the LEDs 14 constituting the light source are provided on the substrate 505, and these are composed of a unit 503 having a plurality of blocks with the collimator 18 and the LED 14 as a pair of blocks. The unit 503 is arranged at both ends of the back surface of the liquid crystal display panel 11 (in this embodiment, 3 units are arranged side by side in the short side direction). The light output from the unit 503 is reflected by the reflective light guide 504 and is configured to be incident on the oppositely arranged liquid crystal display panel 11 (not shown).

[0125] The reflective light guide 504 is divided into two blocks corresponding to the units arranged at its respective ends and is arranged such that the central part is the highest. Since the collimator 18 is close to the LED 14, a glass material is adopted in consideration of the heat resistance to the heat generated from the LED 14. The shape of the collimator 18 is the same as the shape of the collimator 18 in FIG. 14A(3).

[0126] The light from LED14 enters the polarization conversion element 501 through the collimator 18. The configuration is such that the distribution of the light incident on the subsequent reflective light guide 504 is adjusted according to the shape of the optical element 81. That is, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 is optimally designed by adjusting the shape of the collimator 18 described above, the arrangement, the shape of the optical element 81, the diffusion characteristics, the reflection surface shape (cross-sectional shape) of the reflective light guide, the inclination of the reflection surface, and the surface roughness of the reflection surface.

[0127] As the reflection surface shape provided on the surface of the reflective light guide 504, as shown in FIG. 4(b), a plurality of reflection surfaces are arranged facing the emission surface of the polarization conversion element, and according to the distance from the polarization conversion element 21, the inclination, area, height, and pitch of the reflection surface are optimized. Further, by dividing the region that becomes the same reflection surface (that is, the surface facing the polarization conversion element) into polyhedrons, the light quantity distribution of the light beam incident on the liquid crystal display panel 11 can be set to a desired value (optimized) as described above. For this reason, the light quantity and the emission direction of the light beam heading toward the liquid crystal display panel 11 can be adjusted with high precision. As a result, since the light quantity and the emission direction of the incident light on the liquid crystal display panel 11 and the emitted light from the liquid crystal display panel 11 can also be controlled with high precision, in the spatial floating image display system using the video display device using this light source, the diffusion direction and the diffusion angle of the image light of the spatial floating image can be set to desired values (refer to the four solid arrows incident on the light guide in FIG. 13B(2)).

[0128] Similar to the reflective light guide 306 described with reference to FIG. 13B, the reflection surface provided on the reflective light guide is configured such that one surface (the region for reflecting light) has a shape with a plurality of inclinations (in the example of FIG. 4, it is divided into 14 parts in the XY plane and is composed of different inclined surfaces), so that the reflected light can be adjusted with higher precision. Further, in order to prevent the reflected light from the reflective light guide from leaking from the side surface of the light source device 13, by providing the light shielding wall 507, it is possible to prevent the generation of leakage light in directions other than the desired direction (the direction toward the liquid crystal display panel 11).

[0129] Further, the unit 503 disposed on the left and right of the reflective light guide 504 in FIG. 4 may be replaced with the light source device in FIG. 13A. That is, a plurality of light source devices (substrate 102, reflector 300, LED 14, etc.) in FIG. 13A may be prepared, and such a plurality of light source devices may be arranged at positions facing each other as shown in FIGS. 4(a), (b), and (c).

[0130] FIG. 18(B) is a light source device configured by arranging six units 503 shown in FIG. 18(A) at the upper part and six units 503 at the lower part. The light source device shown in FIG. 18(B) has a configuration in which the unit 503 with five LEDs arranged horizontally is arranged as described above, and the current is controlled by a single power supply to obtain a desired luminance. Therefore, as a light source device for illuminating a liquid crystal panel, the light source luminance can be controlled for each region irradiated by each unit 503.

[0131] The configuration shown in FIG. 18 includes a reflection surface 222 and a reflection surface 502 different from the reflection surface 222. Among these, the reflection surface 222 has a shape like a horizontal grid or a strip shape having a predetermined width. On the other hand, the reflection surface 502 has a shape like a vertical and horizontal grid. By optimally designing the shapes of these fine grids and the inclination of the dividing surface, a desired emission light distribution (emission direction and diffusion characteristics of the emission light) can be obtained.

[0132] As a result, similar to the above-described two embodiments, since the amount of light and the emission direction of the incident light to the liquid crystal display panel 11 and the emission light from the liquid crystal display panel 11 can be controlled with the same high precision, in a spatial floating image display system using a video display device using this light source, the diffusion direction and diffusion angle of the video light of the spatial floating image can be set to desired values.

[0133] <Structure of Diffusion Plate> FIG. 15 is a cross-sectional view showing an example of the shape of the diffusion plate 206. As described above, the emitted light output from the LED is converted into substantially parallel light by the reflector 300 or the collimator 18, and after being converted into a specific polarization state by the polarization conversion element 21, it is reflected by the light guide. Then, the light beam reflected by the light guide passes through the flat portion of the incident surface of the diffusion plate 206 and enters the liquid crystal display panel 11 (see the two solid arrows indicating "reflected light from the light guide" in FIG. 15).

[0134] Also, among the light emitted from the polarization conversion element 21, the divergent light beam is totally reflected by the inclined surface of the protrusion having an inclined surface provided on the incident surface of the diffusion plate 206 and enters the liquid crystal display panel 11. In order to totally reflect the light emitted from the polarization conversion element 21 by the inclined surface of the protrusion of the diffusion plate 206, the angle of the inclined surface of the protrusion is changed based on the distance from the polarization conversion element 21. When the angle of the inclined surface of the protrusion on the side far from the polarization conversion element 21 or the side far from the LED is α, and the angle of the inclined surface of the protrusion on the side close to the polarization conversion element 21 or the side close to the LED is α', α is smaller than α' (α < α'). By setting it in this way, it becomes possible to effectively utilize the polarized light-converted light beam.

[0135] <Diffusion characteristic control technology of video display device> As a method for adjusting the diffusion distribution of the video light from the liquid crystal display panel 11, it is possible to provide a lenticular lens between the light source device 13 and the liquid crystal display panel 11 or on the surface of the liquid crystal display panel 11 and optimize the shape of the lens. That is, by optimizing the shape of the lenticular lens, it is possible to adjust the emission characteristics of the video light (hereinafter also referred to as "video light beam") emitted from the liquid crystal display panel 11 in one direction.

[0136] Alternatively or additionally, a microlens array may be arranged in a matrix on the surface of the liquid crystal display panel 11 (or between the light source device 13 and the liquid crystal display panel 11), and the arrangement mode may be adjusted. That is, by adjusting the arrangement of the microlens array, the emission characteristics of the video light beam emitted from the video display device 1 in the X-axis and Y-axis directions can be adjusted, and as a result, a video display device having desired diffusion characteristics can be obtained.

[0137] As a further configuration example, two lenticular lenses may be arranged in combination at the position where the video light emitted from the video display device 1 passes, or a sheet for adjusting the diffusion characteristics by arranging a microlens array in a matrix may be provided. By adopting such an optical system configuration, in the X-axis and Y-axis directions, the luminance (relative luminance) of the video light can be adjusted according to the reflection angle of the video light (the reflection angle with respect to the case of reflecting in the vertical direction as the reference (0 degrees)).

[0138] In this embodiment, by using such a lenticular lens, as shown in the graphs (plot curves) of "Example 1 (Y direction)" and "Example 2 (Y direction)" in FIG. 20(B), excellent optical characteristics that are clearly different from the graph (plot curve) of the conventional characteristics can be obtained. Specifically, in the plot curves of Example 1 (Y direction) and Example 2 (Y direction), the luminance characteristics in the vertical direction are made steeper, and further, by changing the balance of the directivity characteristics in the up and down directions (positive and negative directions of the Y-axis), the luminance (relative luminance) of the light due to reflection and diffusion can be increased.

[0139] Therefore, according to this embodiment, it is possible to adjust so as to suppress the ghost image generated in the retroreflective member when using a conventional video display device for video light having a narrow diffusion angle (high straightness) and only a specific polarization component, such as video light from a surface-emitting laser video source, and efficiently deliver the spatial floating image due to retroreflection to the viewer's eyes.

[0140] In addition, with the light source device described above, it is possible to provide significantly angled directivity characteristics in both the X-axis direction and the Y-axis direction with respect to the light emission diffusion characteristics from a general liquid crystal display panel shown in FIGS. 20(A) and (B) (denoted as "conventional characteristics" in the figures). In this embodiment, by providing such narrow-angle directivity characteristics, it is possible to realize a video display device that emits light of a specific polarization and emits a video light beam that is nearly parallel in a specific direction.

[0141] FIG. 19 shows an example of the characteristics of the lenticular lens employed in this embodiment. In this example, in particular, the characteristics in the X direction (vertical direction) with respect to the Z axis are shown. For characteristic O, the peak in the light emission direction is at an angle of approximately 30 degrees upward from the vertical direction (0 degrees) and shows a luminance characteristic that is symmetric about the vertical axis. Also, the plot curves of characteristics A and B shown in the graph of FIG. 19 are examples of characteristics in which the video light above the peak luminance is condensed at around 30 degrees to increase the luminance (relative luminance). Therefore, in these characteristics A and B, as can be seen by comparison with the plot curve of characteristic O, in the region where the inclination (angle θ) from the Z axis to the X direction exceeds 30 degrees (θ > 30°), the luminance (relative luminance) of the light rapidly decreases.

[0142] That is, according to the optical system including the lenticular lens described above, when the video light beam from the video display device 1 is incident on the retroreflective member, the emission angle and the viewing angle of the video light aligned at an included angle by the light source device 13 can be adjusted, and the degree of freedom in installing the retroreflective sheet can be significantly improved. As a result, the degree of freedom in the relationship of the imaging position of the spatial floating image that is reflected or transmitted through the windshield and imaged at a desired position can be significantly improved. As a result, it becomes possible to efficiently reach the eyes of outdoor or indoor viewers as light with a narrow diffusion angle (high straightness) and only a specific polarization component. According to this, even if the intensity (luminance) of the video light from the video display device 1 is reduced, the viewer can accurately recognize the video light and obtain information. In other words, by reducing the output of the video display device 1, it becomes possible to realize a display system with low power consumption.

[0143] The various embodiments or examples (i.e., specific examples) to which the present invention is applied have been described in detail above. On the other hand, the present invention is not limited to only the above-described embodiments (specific examples), and includes various modifications. For example, the above-described embodiments have described the entire system in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of one embodiment. Further, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

[0144] The light source device described above is not limited to the spatial floating image display device, and can also be applied to display devices such as HUDs, tablets, digital signage, and the like.

[0145] In the technology according to this embodiment, by displaying a high-resolution and high-brightness spatial floating image in a spatially floating state, for example, it becomes possible for a user to operate without feeling anxiety about contact infection of infectious diseases. If the technology according to this example is used in a system used by an unspecified number of users, it becomes possible to reduce the risk of contact infection of infectious diseases and provide a contactless user interface that can be used without feeling anxiety. According to the present invention that provides such a technology, it contributes to "3 Good health and well-being for all" among the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0146] In addition, in the technology according to the above-described embodiment, by reducing the divergence angle of the emitted video light and further aligning it to a specific polarization, only the regular reflected light is efficiently reflected from the retroreflective member, so that the light utilization efficiency is high and a bright and clear floating image can be obtained. According to the technology of this embodiment, it is possible to provide a non-contact user interface with excellent usability that can significantly reduce power consumption. According to the present invention that provides such a technology, it contributes to "Build the foundation for industry and technological innovation" and "Build sustainable cities" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

[0147] Furthermore, in the technology according to the above-described embodiment, it is possible to form a floating image by video light with high directivity (straightness). In the technology according to Example 5, even when displaying an image that requires high security in an ATM of a bank or a ticket vending machine at a station, or an image with high confidentiality that needs to be hidden from a person facing the user, by displaying video light with high directivity, it is possible to provide a non-contact user interface with a low risk of being peeked at the floating image by anyone other than the user. By providing the above-described technology, the present invention contributes to "Build sustainable cities" among the Sustainable Development Goals (SDGs) proposed by the United Nations.

Explanation of Reference Numerals

[0148] 1… Image display device, 2… First retroreflective member, 5… Second retroreflective member, 3… Spatial image (spatial floating image), 100… Transparent plate, 13… Light source device, 54… Light direction conversion panel, 105… Linear Fresnel sheet, 101… Absorptive polarizing sheet (absorptive polarizer), 200… Flat panel display, 201… Housing, 203… Sensing system, 226… Sensing area, 102… Substrate, 11, 335… Liquid crystal display panel, 206… Diffusion plate, 21… Polarization conversion element, 300… Reflector, 213… λ / 2 plate, 306… Reflective light guide, 307… Reflective surface, 308, 310… Sub-reflector, 204… Spatial floating video, 334… Video light control sheet, 336… Transmissive portion, 337… Light absorption portion, 81… Optical element, 501… Polarization conversion element, 503… Unit, 507… Light shielding wall, 401, 402… Light shielding plate, 320… Base material, 511… Housing, 512… Support arm, 513… Hinge, 514… Back cover, 515… Housing cover, 516… Housing base.

Claims

1. A spatial floating image display system, comprising: A display panel for displaying an image; A light source device for supplying light to the display panel; A retroreflective member that reflects the image light from the display panel and displays a real image spatial floating image in the air by the reflected light; Characterized in that The retroreflective member includes a retardation plate, and the retardation plate having inverse wavelength dispersion is laminated on the image light incident surface side of the retroreflective member. A spatial floating image display system.

2. The spatial floating image display system according to claim 1, wherein The retroreflective member includes a reflective layer, a transmissive substrate, and a reflective surface. A spatial floating image display system.

3. The spatial floating image display system according to claim 2, wherein The retroreflective member is configured to include, in order from the image light incident surface side of the retroreflective member, the retardation plate, the transmissive substrate, the reflective layer, the transmissive substrate, and the reflective surface. A spatial floating image display system.

4. The spatial floating image display system according to claim 1, wherein The retardation plate is made of a polycarbonate material. A spatial floating image display system.

5. The spatial floating image display system according to claim 2, further comprising An image light control sheet disposed on the image light emission side of the display panel, The image light control sheet adjusts the emission direction and divergence angle of the image light beam emitted from the display panel. A spatial floating image display system.

6. The spatial floating image display system according to claim 1, wherein The image light control sheet is a viewing angle control film of the display panel. A spatial floating image display system.

7. The spatial floating image display system according to claim 1, wherein The divergence angle and divergence direction of the image light beam diffused from the spatial floating image are adjusted by the diffusion characteristics of the image light control sheet and the light source device. A spatial floating image display system.

8. The spatial floating image display system according to claim 1, wherein The light source device includes: A point-shaped or surface-shaped light source; A reflector for reflecting the light from the light source; A light guide for guiding the light from the reflector toward the display panel, The reflecting surface of the reflector has an asymmetric shape with respect to the optical axis of the emitted light of the light source. A spatial floating image display system.

9. The spatial floating image display system according to claim 8, wherein The light guide is a transmissive light guide. A spatial floating image display system.

10. The spatial floating image display system according to claim 8, wherein The light guide is a reflective light guide, A spatial floating image display system.

11. In the spatial floating image display system according to claim 8, A diffusion plate that diffuses the light from the light guide, A side wall disposed so as to sandwich the space between the light guide and the diffusion plate, A spatial floating image display system.

12. In the spatial floating image display system according to claim 8, The reflector uses a plastic material, a glass material, or a metal material, A spatial floating image display system.

13. In the spatial floating image display system according to claim 8, The light source light reflection surface of the light guide has a configuration in which a plurality of reflection surfaces are arranged in a direction perpendicular to the optical axis along which the light source light propagates, and the emission direction and diffusion angle of the light source light incident on the display panel are adjusted by the inclination angle of each of the reflection surfaces, A spatial floating image display system.

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