JP2022089750A - Space floating video display device and light source device - Google Patents

Abstract

To obtain a space floating video display device that can obtain a space floating video with less ghost and influence of external light, has high visibility, and is compact, which, according to the present invention, contributes to "3 Ensure healthy lives and promote well-being for all at all ages," "9 Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," and "11 Make cities and human settlements inclusive, safe, resilient and sustainable" in Sustainable Development Goals.SOLUTION: A space floating video display device comprises: a liquid crystal display panel as a video source; a light source device that supplies light in a specific polarization direction to the liquid crystal display panel; and a retroreflective member that is provided with a phase difference plate on a retroreflective surface. A polarization separation member is provided in a space connecting the liquid crystal display panel and the retroreflective member. The polarization separation member once transmits video light of a specific polarized wave from the liquid crystal display panel toward the retroreflective member, performs polarization conversion with the retroreflective member to convert the polarized wave of the video light into the other polarized wave, thereby causing the video light to be reflected on the polarization separation member, and displays a space floating video light being a real image on the opposite side of the video source in a transparent member through which the video light of the specific polarized wave is transmitted.SELECTED DRAWING: Figure 6A

Description

The present invention relates to a space floating image display device and a light source device.

As an example of the spatial floating image display device, Patent Document 1 states that "the CPU of the information processing device has an approach direction detecting unit that detects the approach direction of the user to an image formed in the air and the coordinates at which the input is detected. The CPU includes an input coordinate detection unit for detecting, an operation reception unit for processing the reception of operations, and an operation screen update unit for updating the operation screen according to the received operation. The CPU displays an image from a direction predetermined by the user. When approaching, the user's movement is accepted as an operation, and the process according to the operation is executed (summary excerpt). "

Japanese Unexamined Patent Publication No. 2019-128722

The above-mentioned spatial floating image display device of Patent Document 1 can improve the operability of the spatial floating image, but does not consider the improvement of the apparent resolution and contrast of the spatial floating image, and further images. There is a fact that quality improvement is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a spatial floating image display device capable of displaying a suitable and highly visible spatial floating image.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above problems, and to give an example thereof, a liquid crystal display panel as an image source, a light source device for supplying light in a specific polarization direction to the liquid crystal display panel, and retroreflection. A retroreflective member having a retardation plate on the surface thereof is provided, and a polarization separating member is provided in the space connecting the liquid crystal display panel and the retroreflective member, and the polarization separating member is from the liquid crystal display panel. The image light of the specific polarization is once transmitted to the retroreflective member, polarized and converted by the retroreflective member and converted to the other polarization, and then reflected by the polarization separating member to be reflected by the polarization separation member. In the transparent member through which light passes, a spatial floating image which is a real image is displayed on the opposite side of the image source.

According to the present invention, it is possible to realize a spatial floating image display device capable of displaying a suitable and highly visible spatial floating image. Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a figure which shows an example of the usage form of the space floating image display system which concerns on one Embodiment of this invention. It is a figure which shows an example of the main part structure and the retroreflection part structure of the space floating image display system which concerns on one Embodiment of this invention. It is a figure which shows the problem of the space floating image display system. It is a characteristic diagram which shows the relationship between the surface roughness of a retroreflection member and the amount of blurring of a retroreflection image. It is a figure which shows the problem of the space floating image display system. It is a figure which shows the other implementation of the main part composition of the space floating image display device which concerns on one Embodiment of this invention. It is a figure which shows the other implementation of the main part composition of the space floating image display device which concerns on one Embodiment of this invention. It is a figure which shows the other implementation of the main part composition of the space floating image display device which concerns on one Embodiment of this invention. It is a figure which shows the other implementation of the main part composition of the space floating image display device which concerns on one Embodiment of this invention. It is a figure which shows the other implementation of the main part composition of the space floating image display device which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the specific structure of a light source device. It is sectional drawing which shows an example of the specific structure of a light source device. It is sectional drawing which shows an example of the specific structure of a light source device. It is a layout drawing which shows the main part of the space floating image display system which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the image display apparatus which constitutes the space floating image display system which concerns on one Embodiment of this invention. It is sectional drawing which shows an example of the specific structure of a light source device. It is sectional drawing which shows an example of the specific structure of a light source device. It is sectional drawing which shows an example of the specific structure of a light source device. It is explanatory drawing for demonstrating the diffusion characteristic of a video display device. It is explanatory drawing for demonstrating the diffusion characteristic of a video display device. It is sectional drawing which shows the structure of the image display apparatus which constitutes the space floating image display system which concerns on one Embodiment of this invention. It is a figure which shows an example of the specific structure of the light source apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the description of the examples, and various modifications and modifications by those skilled in the art can be made within the scope of the technical idea disclosed in the present specification. Further, in all the drawings for explaining the present invention, the same reference numerals may be given to those having the same function, and the repeated description thereof may be omitted. In the following description of the embodiment, the image floating in space is expressed by the term "space floating image". Instead of this term, it may be expressed as "airborne floating image", "spatial floating optical image of displayed image", or "air floating optical image of displayed image". The term "spatial floating image" used in the description of the examples is used as a representative example of these terms.

In the following embodiment, for example, an image generated by an image light from a large-area image emitting source is transmitted through a transparent member that partitions a space such as a show window glass, and the space is inside or outside the store (space). The present invention relates to a spatial floating image display system that can be displayed as a floating image. Further, the present invention relates to a large-scale digital signage system configured by using a plurality of such spatial floating image display systems.

According to the following embodiment, for example, high-resolution video information can be displayed in a spatially floating state on a glass surface of a show window or a light-transmitting plate material. At this time, by making the divergence angle of the emitted image light small, that is, making it a sharp angle, and further aligning it with a specific polarization, only the normal reflected light is efficiently reflected to the retroreflective member, so that the light utilization efficiency is improved. It is expensive, and it is possible to suppress ghost images generated in addition to the main space floating image, which has been a problem in the conventional retroreflection method, and it is possible to obtain a clear space floating image. Further, the device including the light source of the present embodiment can provide a new and highly usable spatial floating image display system capable of significantly reducing power consumption. Further, for example, a floating image display system for a vehicle capable of displaying a so-called one-way spatial floating image that can be visually recognized outside the vehicle via a shield glass including a windshield, a rear glass, and a side glass of the vehicle is provided. be able to.

On the other hand, in the conventional space floating image display system, an organic EL panel or a liquid crystal display panel is combined with a retroreflective member as a high-resolution color display image source. Since the image light is diffused at a wide angle in the space floating image display device according to the prior art, in addition to the reflected light that is normally reflected because the retroreflective part is a hexahedron, as shown in FIG. A ghost image was generated by the image light incident on the sheet) 2 from an angle, and the image quality of the spatial floating image was impaired. Since the retroreflective member shown as the prior art is a hexahedron, a plurality of first ghost images G1 to sixth ghost images G6 are generated in addition to the normal image R1 of the spatial floating image as shown in FIG. For this reason, a ghost image, which is a floating image in the same space, is monitored by other than the viewer, which poses a big problem in terms of security.

In addition to the ghost image described above, the spatial floating image obtained by reflecting the image light from the image display device having a narrow-angle directional characteristic, which will be described later, by the retroreflective member is the pixel of the liquid crystal display panel as shown in FIG. Blurring was visually recognized every time.

<Spatial floating image display system (1)>
FIG. 1 is a diagram showing an example of a usage mode of a space floating image display system according to an embodiment of the present invention. FIG. 1A is a diagram showing an overall configuration of a space floating image display system according to this embodiment. For example, in a store or the like, the space is partitioned by a show window (wind glass 105) which is a translucent member such as glass. According to the spatial floating information display system of the present embodiment, it is possible to display the floating image in one direction to the outside of the store (space) through the transparent member. Specifically, light having a narrow-angle directional characteristic and a specific polarization is emitted from the image display device 1 as an image luminous flux, is once incident on the retroreflective member 2, is retroreflected, and is transmitted through the wind glass 105. , An aerial image (spatial floating image 3), which is a real image, is formed on the outside of the store. In FIG. 1, the inside of the wind glass 105 (inside the store) is shown in the depth direction so that the outside (for example, a sidewalk) is in front of the wind glass 105. On the other hand, it is also possible to reflect the specific polarization by providing the wind glass 105 with a means for reflecting the specific polarization, and to form an aerial image at a desired position in the store.

FIG. 1B is a block diagram showing the configuration of the above-mentioned video display device 1. The video display device 1 includes a video display unit 1a for displaying the original image of an aerial image, a video control unit 1b for converting the input video according to the resolution of the panel, and a video signal receiving unit 1c for receiving the video signal. , The receiving antenna 1d and the like are included. The video signal receiving unit 1c supports wired input signals such as HDMI (High-Definition Multimedia Interface: registered trademark) input, and supports wireless input signals such as Wi-Fi (Wireless Fieldy: registered trademark). It also functions independently as a video receiving / displaying device, and can also display video information from tablets, smartphones, and the like. Furthermore, if a stick PC or the like is connected, it is possible to have capabilities such as calculation processing and video analysis processing.

FIG. 2 is a diagram showing an example of a main part configuration and a retroreflective part configuration of the spatial floating image display system according to the embodiment of the present invention. The configuration of the spatial floating image display system will be described more specifically with reference to FIG. As shown in FIG. 2A, an image display device 1 that emits image light having a specific polarization in a narrow angle is provided in an oblique direction of a transparent member 100 such as glass. The image display device 1 includes a liquid crystal display panel 11 and a light source device 13 that generates light having a specific polarization having a narrow-angle diffusion characteristic.

The image light of the specific polarization from the image display device 1 has a polarization separation member 101 having a film provided on the transparent member 100 for selectively reflecting the image light of the specific polarization (in the figure, the polarization separation member 101 is in the form of a sheet). It is formed on the surface of the transparent member 100 and is reflected by the transparent member 100), and is incident on the retroreflective member 2. A λ / 4 plate 21 is provided on the image light incident surface of the retroreflective member. The image light is polarized and converted from the specific polarization to the other polarization by being passed through the λ / 4 plate 21 twice, when it is incident on the retroreflective member 2 and when it is emitted. Here, since the polarization separating member 101 that selectively reflects the image light of the specific polarization has the property of transmitting the polarization of the other polarization that has been polarized, the image light of the specific polarization after the polarization conversion can be obtained. It passes through the polarization separating member 101. The image light transmitted through the polarization separating member 101 forms a spatial floating image 3 which is a real image on the outside of the transparent member 100.

The light forming the spatial floating image 3 is a set of light rays that converge from the retroreflective member 2 to the optical image of the spatial floating image 3, and these rays travel straight even after passing through the optical image of the spatial floating image 3. .. Therefore, the spatial floating image 3 is an image having high directivity, unlike the diffused image light formed on the screen by a general projector or the like. Therefore, in the configuration of FIG. 2, when the user visually recognizes from the direction of arrow A, the spatial floating image 3 is visually recognized as a bright image, but when another person is visually recognized from the direction of arrow B, the spatial floating image 3 is visually recognized. 3 cannot be visually recognized as an image at all. This characteristic is very suitable for use in a system that displays a video that requires high security or a video that is highly confidential and that is desired to be kept secret from the person facing the user.

Depending on the performance of the retroreflective member 2, the polarization axes of the reflected image light may be uneven. In this case, a part of the video light whose polarization axes are not aligned is reflected by the above-mentioned polarization separation member 101 and returns to the video display device 1. This light may be re-reflected on the image display surface of the liquid crystal display panel 11 constituting the image display device 1, generate a ghost image, and deteriorate the image quality of the spatial floating image. Therefore, in this embodiment, the absorption type polarizing plate 12 is provided on the image display surface of the image display device 1. The rereflection can be suppressed by transmitting the image light emitted from the image display device 1 through the absorption type polarizing plate 12 and absorbing the reflected light returned from the polarization separating member 101 by the absorption type polarizing plate 12. This makes it possible to prevent deterioration of image quality due to the ghost image of the spatial floating image.

The above-mentioned polarization separating member 101 may be formed of, for example, a reflective polarizing plate or a metal multilayer film that reflects a specific polarization.

Next, as a typical retroreflective member 2 in FIG. 2B, the surface shape of the retroreflective member 2 manufactured by Nippon Carbite Industries Co., Ltd. used in this study is shown. The light rays incident on the inside of the retroreflective part 2a composed of regularly arranged hexagonal prisms are reflected by the wall surface and the bottom surface of the hexagonal prisms and emitted as retroreflected light in the direction corresponding to the incident light, which is normal as shown in FIG. Form image R1. On the other hand, as shown in FIG. 3, a ghost image (G1 to G6 in FIG. 5) is separated from the normal image R1 depending on the image light obliquely incident on the retroreflective member 2 in the image light from the image display device 1. Is formed.

Therefore, based on the image displayed on the image display device 1 of the present invention, the spatial floating image 3 which is a real image is displayed without forming a ghost image. The resolution of the spatial floating image 3 largely depends on the outer diameter D and the pitch P of the retroreflective portion 2a of the retroreflective member 2 shown in FIG. 2B in addition to the resolution of the liquid crystal display panel 11. For example, when a 7-inch WUXGA (1920 × 1200 pixels) liquid crystal display panel 11 is used, even if one pixel (1 triplet) is about 80 μm, for example, the diameter D of the retroreflective portion 2a is 240 μm and the pitch is 300 μm. If so, one pixel of the spatial floating image 3 is equivalent to 300 μm. Therefore, the effective resolution of the spatial floating image 3 is reduced to about 1/3. Therefore, in order to make the resolution of the spatial floating image 3 equal to the resolution of the image display device 1, it is desired that the diameter and pitch of the retroreflective portion 2a be close to one pixel of the liquid crystal display panel. On the other hand, in order to suppress the occurrence of moire due to the pixels of the retroreflective member 2 and the liquid crystal display panel 11, it is preferable to design by removing the pitch ratio of each from the integral multiple of one pixel. Further, the shape may be arranged so that neither side of the retroreflective portion 2a overlaps with any one side of one pixel of the liquid crystal display panel 11.

The inventors have described the relationship between the amount of blurring of an image of a spatially floating image and the pixel size L, which is acceptable for improving visibility, with a liquid crystal display panel having a pixel pitch of 40 μm and a narrow divergence angle (divergence angle of 15 °) of the present invention. An image display device 1 combined with the light sources of the above was created and obtained by an experiment. The experimental result of FIG. 4 is shown. It was found that the amount of blur l, which deteriorates visibility, is preferably 40% or less of the pixel size, and is hardly noticeable if it is 15% or less. The surface roughness of the reflective surface at which the blur amount l at this time is an allowable amount has an average roughness of 160 nm or less in the range of a measurement distance of 40 μm, and the surface roughness of the reflective surface is 120 nm or less in order to make the blur amount l less noticeable. Turned out to be desirable. Therefore, it is desired to reduce the surface roughness of the retroreflective member described above and to reduce the surface roughness including the reflective film forming the reflective surface and the protective film thereof to the above-mentioned values or less.

On the other hand, in order to manufacture the retroreflective member 2 at a low price, it is preferable to mold it by using a roll press method. Specifically, it is a method of aligning the retroreflective portions 2a and shaping them on the film. The inverted shape of the shape to be shaped is formed on the roll surface, and the UV curable resin is applied on the base material for fixing to roll. By passing through the space, a required shape is formed and cured by irradiating with ultraviolet rays to obtain a retroreflective member 2 having a desired shape.

The image display device 1 of the present invention is an image from an oblique angle with respect to the retroreflection member 2 described above by the liquid crystal display panel 11 and the light source device 13 that generates light having a specific polarization having a narrow-angle diffusion characteristic described in detail later. It is a structurally excellent system in which the possibility of incident is small and the brightness is low even if ghosts occur.

<Spatial floating image display system (2)>
FIG. 6A is a diagram showing another example (second example) of the main part configuration of the spatial floating image display system according to the embodiment of the present invention. The image display device 1 includes a liquid crystal display panel 11 as an image display element and a light source device 13 that generates light having a specific polarization having a narrow-angle diffusion characteristic. The liquid crystal display panel 11 is composed of a small one having a screen size of about 5 inches and a large liquid crystal display panel having a screen size of more than 80 inches. For example, the polarization separating member 101 such as a reflective polarizing plate reflects the image light from the liquid crystal display panel toward the retroreflective member 2.

A λ / 4 plate 21 is provided on the light incident surface of the retroreflective member 2, and the polarization is converted by passing the video light twice, and the specific polarization is converted to the other polarization, so that the polarization separation member 101 is transmitted. The space floating image 3 which is a real image is displayed on the outside of the transparent member 100. An absorption-type polarizing plate is provided on the external light incident surface of the transparent member 100. In the polarization separating member 101 described above, the polarization axes become uneven due to retroreflection, so that a part of the image light is reflected and returns to the image display device 1. This light is reflected again on the image display surface of the liquid crystal display panel 11 constituting the image display device 1, generates a ghost image, and significantly deteriorates the image quality of the spatial floating image 3. Therefore, in this embodiment, an absorbent polarizing plate 12 is provided on the image display surface of the image display device 1, the image light is transmitted, and the above-mentioned reflected light is absorbed to prevent deterioration of the image quality due to the ghost image of the spatially floating image 3. ..

Further, in order to reduce the deterioration of image quality due to sunlight or illumination light outside the set, it is preferable to provide the absorption type polarizing plate 112 on the surface of the transparent member 100. Further, when external light is incident on the retroreflective member 2, a strong ghost image is generated, so that the fourth light-shielding member 25 is configured to prevent the external light from being incident. The polarization separating member 101 is formed of a reflective polarizing plate or a metal multilayer film that reflects a specific polarization.

Between the polarization separation member 101 and the liquid crystal display panel 11, a second light-shielding member 23 and a third light-shielding member 24 that block oblique image light other than the normal image light forming the spatial floating image are provided. Further, a first light-shielding member 22 that shields oblique image light other than the normal image light is also provided between the retroreflective member 2 and the polarization separating member 101 so that external light does not directly enter the retroreflective member 2 as described above. A fourth light-shielding member 25 is also installed in the same area to block oblique light that generates a ghost image. As a result, the generation of ghost images can be suppressed.

The inventors have confirmed through experiments that the light-shielding effect can be enhanced by installing the third light-shielding member 24 and the second light-shielding member 23 in the space between the liquid crystal display panel 11 and the polarization separating member 101. In this experiment, the inner diameters of the second light-shielding member 23 and the third light-shielding member 24 are set to 110% in area with respect to the area through which the normal image luminous flux forming the spatial floating image passes, so that the component accuracy is within the range of the machine tolerance. Can be created and assembled with. Further, in order to further reduce the generation of ghost images, if the ratio is 104% or less of the region through which the normal image luminous flux of the above-mentioned light-shielding member passes, the generation of ghost images can be suppressed to a level at which there is no practical problem. On the other hand, the first light-shielding member 22 provided between the retroreflective member 2 and the polarization separating member 101 sets the distance L1 between the first light-shielding member 22 and the retroreflective member 2 with respect to the distance between the retroreflective member 2 and the polarization separating member 101. If it is 50% or less, the generation of ghost images can be further reduced, and if it is 30% or less, it can be reduced to a level where there is no practical problem visually. Further, the ghost level could be further reduced by providing the fourth light-shielding member 25, the first light-shielding member 22, the second light-shielding member 23, and the third light-shielding member 24 provided so as to surround the retroreflective member 2.

The cross-sectional shape of the light-shielding member in FIG. 6A is an effective area of the light-shielding member with respect to a region through which a normal image light flux forming a spatial floating image passes (corresponding to a region through which the image light flux in the absorption-type polarizing plate 112 passes in the present embodiment). It is even better to make the size approximately the same as that of the beam and to absorb the abnormal light by providing a beam toward the inner surface and reflecting the abnormal light forming a ghost image multiple times on the surface of the beam. The area through which the normal image luminous flux passes is made smaller than the outer frame of the light-shielding member so that the area is equivalent to the inscribed surface of the beam.

On the other hand, even if a ghost image is generated by the oblique image light reflected by the retroreflective member 2 as a concave surface or a convex surface having a radius of curvature of 200 mm or more from a planar shape facing the image display device 1 from the shape of the retroreflective member 2, after reflection. The generated ghost image may be kept away from the viewer's view so that it cannot be monitored. Among the light reflected around the retroreflective member 2 having a radius of curvature of 100 mm or less, a new problem arises in which the amount of peripheral light of the spatially floating image 3 obtained by reducing the amount of normally reflected light is reduced. Therefore, in order to reduce the ghost image to a level where there is no practical problem, it is advisable to select and apply the above-mentioned technical means, or to use them together.

<Spatial floating image display system (3)>
FIG. 6B is a diagram showing another example (third example) of the main part configuration of the space floating image display device according to the embodiment of the present invention. The image display device 1 includes a liquid crystal display panel 11 as an image display element and a light source device 13 that generates light having a specific polarization having a narrow-angle diffusion characteristic. The liquid crystal display panel 11 is composed of a small one having a screen size of about 5 inches and a large liquid crystal display panel 11 having a screen size of more than 80 inches. For example, a polarization separating member 101 such as a reflective polarizing plate temporarily transmits the image light from the liquid crystal display panel 11 toward the retroreflective member 2.

A λ / 4 plate 21 is provided on the light incident surface of the retroreflective member 2, and the polarization separation member 101 reflects the specific polarization by converting the specific polarization into the other polarization by passing the video light twice. The space floating image 3 which is a real image is displayed on the outside of the transparent member 100. An absorption-type polarizing plate 112 is provided on the incident surface of the transparent member 100 against external light. The transparent member 100 is a transparent body only in a portion through which the image light passes, and the other portion is composed of a light-shielding member 100b that blocks the light so that the outside light does not enter the set. Depending on the performance of the retroreflective member 2, the polarization axes of the reflected image light may be uneven. In this case, a part of the video light whose polarization axes are not aligned is reflected by the polarization separating member 101 and returns to the video display device 1. This light is re-reflected on the image display surface of the liquid crystal display panel 11 constituting the image display device 1 to generate a ghost image, and the image quality of the spatial floating image 3 is significantly deteriorated. Therefore, in this embodiment, an absorption type polarizing plate 12 is further provided on the image display surface of the image display device 1. Alternatively, by providing an antireflection film (not shown) on the image emitting side surface of the absorption type polarizing plate 12 provided on the surface of the image display device 1, the light of the ghost image is transmitted and absorbed by the absorption type polarizing plate 12. Prevents deterioration of image quality due to the ghost image of the spatial floating image 3.

Further, in order to reduce the deterioration of image quality due to sunlight or illumination light outside the housing 106 that houses the image display device 1 and other optical components, it is preferable to provide an absorbent polarizing plate 112 on the outer surface of the transparent member 100. Further, when external light is incident on the retroreflective member 2, the retroreflective member 2 is tilted (tilt θ) to generate a strong ghost image, and the position away from the window portion 100a formed of a transparent body through which the retroreflective image light passes. It is configured to prevent the incident of external light. Similarly, if the image display device 1 is arranged at a position away from the window portion 100a and the image display device 1 is provided at a position where the image light emitted from the image display device 1 cannot be visually recognized from the window portion 100a, the generation of ghost images is reduced. To. (The window portion 100a is a form of an opening.)

Further, the polarization separating member 101 is formed of a reflective polarizing plate or a metal multilayer film that reflects a specific polarization.

The spatial floating image 3 emitted from the window portion 100a is reflected by the reflection mirror 400. At this time, by setting the angle of the reflection mirror 400 to a desired angle with respect to the plane of the window portion 100a, the position and angle of the obtained spatial floating image 3 can be changed. If the reflection mirror 400 has a characteristic of having a high reflectance of a specific polarization, it can be used as a mirror having high transmittance. Further, if an optical system that obtains spatially floating image light by S polarization is used, high reflectance can be obtained even if a transparent mirror is used without forming a reflective film. As a result, a good spatial floating image with high visibility (denoted as a three-dimensional image in FIG. 6B) can be obtained even by using a transparent mirror, and the viewer does not have an obstacle to monitor the outside view. On the other hand, in the optical system excluding the reflection mirror 400, as shown in FIG. 6B, the planar image shown in the figure can be obtained by the image light transmitted through the window portion 100a.

<Spatial floating image display system (4)>
FIG. 6C is a diagram showing another example (fourth example) of the main part configuration of the space floating image display device according to the embodiment of the present invention. In FIG. 6C, similarly to FIG. 6B, the image display device 1 includes a liquid crystal display panel 11 as an image display element and a light source device 13 that generates light of a specific polarization having a narrow-angle diffusion characteristic. Will be done. The liquid crystal display panel 11 is composed of a small one having a screen size of about 5 inches and a large liquid crystal display panel 11 having a screen size of more than 80 inches. For example, a polarization separating member 101 such as a reflective polarizing plate temporarily transmits the image light from the liquid crystal display panel 11 toward the retroreflective member 2, and the transmitted image light is reflected by the retroreflective member 2. Here, the polarization separating member 101 is also referred to as a beam splitter, and transmits video light with a specific polarization (P polarization or S polarization), but is different from the specific polarization (S polarization or P polarization). ) Has the characteristic of being reflected.

A λ / 4 plate 21 is provided on the light incident surface of the retroreflective member 2, and the polarization separation member 101 reflects the specific polarization by converting the specific polarization into the other polarization by passing the video light twice. The space floating image 3 which is a real image is displayed on the outside of the transparent member 100. Similar to FIG. 6B, an absorption type polarizing plate 112 is provided on the external light incident surface of the transparent member 100. Further, although not shown, as in FIG. 6B, the transparent member 100 may be surrounded by the light-shielding member 100b so that the external light does not enter the retroreflective member 2 or the image display device 1.

The arrangement of the main configuration of the space floating image display device will be described with reference to FIG. 6C. In FIG. 6C, when observing from the observation direction C indicating the arrow direction, the spatial floating image 3 having a two-dimensional planar shape can be observed. The position where the space floating image 3 is formed is determined as follows. In FIG. 6C, the image display device 1 and the retroreflective member 2 are arranged so as to be parallel to each other, and specifically, the image display surface of the liquid crystal display panel 11 and the retroreflective member 2 constituting the image display device 1 are arranged. It is arranged facing the reflective surface. Therefore, it is possible to observe a suitable space floating image 3. On the other hand, the image display surface of the liquid crystal display panel 11 constituting the image display device 1 and the reflection surface of the retroreflective member 2 may be arranged so as to be substantially parallel to each other, and if the angle formed by each other is about 10 degrees. The generated ghost image does not pose a problem in practice, that is, even if the ghost image is generated, it hardly affects the visibility of the spatial floating image 3.

Arbitrary point A on the liquid crystal display panel 11 constituting the image display device 1 (here, one point in the center on the liquid crystal display panel 11) and corresponding point A'on the retroreflective member 2 (similarly, retroreflective). Let the point B where the line segment AA'connecting the central point on the member 2) intersects the polarization splitting member (beam splitter) 101, and let the length of the line segment AB be L1. The line segment AA'is the optical axis of the image light emitted from the image display surface of the liquid crystal display panel 11, and the emission direction of the light source is substantially perpendicular to the image display surface of the liquid crystal display panel 11 or a line segment. AA'is substantially vertical or perpendicular to the image display surface of the liquid crystal display panel 11. Next, a point having a length L2 in the vertical direction (direction in which the transparent member 100 of FIG. 6C is arranged) from the point B on the polarization separating member 101 is set as a point C, and the length L1 of the line segment AB and the line segment BC The length is almost the same as the length L2. Then, the spatial floating image 3 is formed on the two-dimensional plane centered on the point C.

Here, although the description has been made with the central point A on the liquid crystal display panel 11, the above-mentioned relationship of L1 = L2 holds for any point on the liquid crystal display panel 11. Therefore, in FIG. 6C, if the liquid crystal display panel 11 is arranged away from the point B of the polarization separating member 101, L1 becomes long, and because of the relationship of L1 = L2, L2 also becomes long, so that the spatial floating image 3 is formed. The position is higher. That is, the distance from the window portion 100a made of the transparent member 100 to the space floating image 3 becomes long. Therefore, the display position of the spatial floating image 3 changes according to the distance between the liquid crystal display panel 11 and the polarization separating member 101. That is, the display position of the spatial floating image 3 is a position determined according to the distance between the liquid crystal display panel 11 and the polarization separating member 101.

However, when the liquid crystal display panel 11 emits video light of the same intensity, arranging the liquid crystal display panel 11 away from the polarization separating member 101 increases the distance between the liquid crystal display panel 11 and the retroreflective member 2. The intensity (luminance) of the image light reaching the retroreflective member 2 from the liquid crystal display panel 11 is lowered, and as a result, the brightness of the spatial floating image 3 is also lowered. Therefore, since there is a trade-off relationship between the distance from the spatial floating image 3 to be displayed to the transparent member 100 and the brightness of the spatial floating image 3, the arrangement position of the liquid crystal display panel 11 and the polarization separating member 101 should be adjusted. Therefore, it is possible to display the spatial floating image 3 which is suitable and has high visibility.

Further, as is clear from FIG. 6C, when the angle formed by the polarization separating member 101 and the line segment AA'(the optical axis of the image light emitted from the liquid crystal display panel 11) is 45 degrees, The size of the image generated by the image display device 1 and the space floating image 3 are the same. On the other hand, although not shown, when the angle is larger than 45 degrees, the width of the spatial floating image 3 is smaller than that of the image generated by the image display device 1, and conversely, the angle is 45 degrees. When it is smaller than, the width of the spatial floating image 3 becomes larger than the image generated by the image display device 1.

<Spatial floating image display system (5)>
6D and 6E are diagrams showing another example (fifth example) of the main part configuration of the space floating image display device according to the embodiment of the present invention. The spatial floating image display device shown in FIG. 6D is composed of the same parts as those in FIG. 6C, that is, an image display device 1, a retroreflective member 2, a λ / 4 plate 21, a polarization separating member 101, a transparent member 100, and the like. Further, the image display surface of the liquid crystal display panel 11 constituting the image display device 1 and the retroreflection surface of the retroreflection member 2 are arranged so as to face each other.

However, although FIG. 6D and FIG. 6C are arranged so that the image display surface of the liquid crystal display panel 11 constituting the image display device 1 and the reflection surface of the retroreflective member 2 face each other, the retroreflective member 2 is used. Is different in that is located above the image display device 1. That is, the image display device 1 is arranged at a position away from the transparent member 100. Therefore, if the image display device 1 is provided at a position where the image light emitted from the image display device 1 cannot be visually recognized from the transparent member 100, the generation of ghost images is reduced. Further, the retroreflective member 2 is tilted and arranged at a position away from the transparent member 100 through which the retroreflective image light passes, so as to prevent the incident of external light. That is, the direction of the image light emitted from the liquid crystal display panel 11 constituting the image display device 1, in other words, the line segment AA'connecting the point A and the point A'is horizontal in FIG. 6C. In 6D, it is tilted diagonally upward to the left, and is different in that the angle formed by the line segment AA'and the polarization separating member 101 is larger than 45 degrees. As a result of the above, it becomes possible to observe the tilted space floating image 3.

Further, in FIG. 6D, the spatial floating image 3 is formed horizontally as shown in FIG. 6C, whereas the spatial floating image 3 is inclined according to the inclination of the line segments AA'and the inclination angle of the polarization separating member 101. Formed with horns. That is, by changing the inclination of the line segment AA'and the inclination angle of the polarization separating member 101, it is possible to adjust the angle of the plane on which the spatial floating image 3 is formed, and the user's observation direction. It is possible to set S to an appropriate angle.

The spatial floating image display device shown in FIG. 6E is composed of the same parts as those in FIG. 6D, and the arrangement of the parts is the same, but the inclination of the polarization separating member 101 is larger (more horizontally) than in FIG. 6D. (Has a close tilt angle), so that the optical axis of the video light, i.e. the line segment AA', and the angle β formed by the polarization separating member 101 are smaller than the angle α in FIG. 6D. It has become. That is, the relationship is that angle α> angle β.

From the above relationship (angle α> angle β), as shown in FIG. 6E, the observation direction S of the space floating image 3 is in a direction farther from the vertical as compared with FIG. 6D. Further, the observed space floating image 3 is tilted from FIG. 6D.

As described above, by adjusting the direction of the image light, that is, the angle formed by the line segment AA'and the polarization separating member 101 (α or β), the angle formed by the space floating image 3 and the transparent member 100 can be adjusted. Can be changed. Therefore, it is possible to obtain an observation direction suitable for the user.

<Reflective polarizing plate>
The reflective polarizing plate having a grid structure of the present invention has reduced characteristics for light from a direction perpendicular to the polarization axis. Therefore, the specifications along the polarization axis are desirable, and the light source of the present embodiment capable of emitting the image light emitted from the liquid crystal display panel 11 at a narrow angle is an ideal light source. Similarly, the characteristics in the horizontal direction also deteriorate with respect to light from an angle. In consideration of the above characteristics, a configuration example of the present embodiment in which a light source capable of emitting the image light emitted from the liquid crystal display panel 11 at a narrower angle is used as the backlight of the liquid crystal display panel 11 will be described below. This makes it possible to provide a high-contrast spatial floating image 3.

<Video display device>
Next, the video display device 1 of this embodiment will be described with reference to the drawings. The video display device 1 of this embodiment includes a light source device 13 constituting the light source together with a video display element (liquid crystal display panel 11), and in FIG. 7, the light source device 13 is shown as a developed perspective view together with the liquid crystal display panel. ing.

As shown by the arrow 30 in FIG. 7, the liquid crystal display panel (image display element) has a narrow-angle diffusion characteristic due to the light from the light source device 13 which is a backlight device, that is, the directivity (straightness) is high. A wind glass that is strong and has a characteristic similar to that of a laser beam with its polarizing planes aligned in one direction, is obtained, and the image light modulated according to the input image signal is reflected by the retroreflecting member 2. It passes through 105 to form a spatial floating image that is a real image (see FIG. 1). Further, in FIG. 7, a liquid crystal display panel 11 constituting the image display device 1, an optical direction conversion panel 54 for controlling the directivity characteristic of the luminous flux emitted from the light source device 13, and a narrow-angle diffuser plate as needed. It is configured with (not shown). That is, polarizing plates are provided on both sides of the liquid crystal display panel 11, and the video light having a specific polarization is emitted by modulating the light intensity with the video signal (see the arrow 30 in FIG. 7). .. As a result, the desired image is projected as light having a specific polarization having high directivity (straightness) toward the retroreflective member 2 via the optical direction conversion panel 54, reflected by the retroreflective member 2, and then stored in the store. A spatial floating image 3 is formed by transmitting light toward the eyes of an outside viewer of (space). A protective cover 50 (see FIGS. 8 and 9) may be provided on the surface of the above-mentioned optical direction conversion panel 54.

In this embodiment, in order to improve the utilization efficiency of the luminous flux emitted from the light source device 13 (indicated by the arrow 30) and significantly reduce the power consumption, an image including the light source device 13 and the liquid crystal display panel 11 is included. In the display device 1, the light from the light source device 13 (see the arrow 30 in FIG. 8) is projected toward the retroreflective member 2, reflected by the retroreflective member 2, and then a transparent sheet provided on the surface of the wind glass 105. By (not shown), the directivity can be controlled so as to form the spatial floating image 3 at a desired position. Specifically, this transparent sheet controls the imaging position of a floating image while imparting high directivity by an optical component such as a Fresnel lens or a linear Fresnel lens. According to this, the image light from the image display device 1 efficiently reaches the observer outside the wind glass 105 (for example, a sidewalk) with high directivity (straightness) like a laser beam. As a result, it is possible to display a high-quality floating image with high resolution and to significantly reduce the power consumption of the image display device 1 including the LED (Light Emitting Diode) element 201 of the light source device 13.

<Example of video display device (1)>
FIG. 7 is a diagram showing another example of the video display device 1. Further, FIG. 8 shows a state in which the liquid crystal display panel 11 and the optical direction conversion panel 54 are arranged on the light source device 13 of FIG. The light source device 13 is formed of, for example, plastic, and has an LED element 201 and a light guide body 203 housed therein. The end face of the light guide body 203 is shown in FIG. 8 and the like. In order to convert the divergent light from each LED element 201 into a substantially parallel light beam, it has a shape in which the cross-sectional area gradually increases toward the light receiving portion, and it propagates inside multiple times. A lens shape is provided that has the effect of gradually reducing the divergence angle by total internal reflection. A liquid crystal display panel 11 constituting the image display device 1 is attached to the upper surface thereof. Further, an LED element 201 which is a semiconductor light source and an LED substrate 202 (see FIG. 8) on which the control circuit thereof is mounted are attached to one side surface (the left end surface in this example) of the case of the light source device 13. A heat sink, which is a member for cooling the heat generated by the LED element 201 and the control circuit, may be attached to the outer surface of the LED substrate 202.

Further, the frame (not shown) of the liquid crystal display panel 11 attached to the upper surface of the case of the light source device 13 is electrically connected to the liquid crystal display panel 11 attached to the frame and further to the liquid crystal display panel 11. FPC (Flexible Printed Circuits: flexible wiring board) (not shown) or the like (not shown) is attached and configured. That is, the liquid crystal display panel 11 which is an image display element, together with the LED element 201 which is a solid light source, modulates the intensity of transmitted light based on a control signal from a control circuit (not shown) constituting an electronic device. Generates a display image by. At this time, since the generated video light has a narrow diffusion angle and only a specific polarization component, a new video display device 1 that is close to a surface-emitting laser video source driven by a video signal can be obtained. Become. At present, it is technically and safety-wise impossible to obtain a laser luminous flux having the same size as the image obtained by the above-mentioned image display device 1 by using the laser device. Therefore, in this embodiment, for example, light close to the above-mentioned surface emission laser image light is obtained from a light flux from a general light source provided with the LED element 201.

Subsequently, the configuration of the optical system housed in the case of the light source device 13 will be described in detail with reference to FIG. 8 and FIG. 9. Since FIGS. 8 and 9 are cross-sectional views, only one plurality of LED elements 201 constituting the light source are shown, and these are converted into substantially collimated light by the shape of the light receiving end surface 203a of the light guide body 203. .. Therefore, the light receiving portion on the end surface of the light guide body and the LED element 201 are attached while maintaining a predetermined positional relationship. Each of the light guides 203 is made of a translucent resin such as acrylic. The LED light receiving surface at the end of the light guide has, for example, a conical convex outer peripheral surface obtained by rotating a paraboloid cross section, and at the top thereof, a convex portion (that is, a convex lens surface) is formed at the center thereof. ) Is formed, and a convex lens surface protruding outward (or a concave lens surface recessed inward may be used) is provided in the central portion of the flat surface portion (not shown). The outer shape of the light receiving portion of the light guide body 203 has a parabolic shape forming a conical outer peripheral surface, and is an angle at which light emitted from the LED element 201 in the peripheral direction can be totally reflected inside. It is set within the range of, or a reflective surface is formed.

On the other hand, the LED element 201 is arranged at a predetermined position on the surface of the LED substrate 202, which is the circuit board thereof. The LED substrate 202 is fixed to the LED collimator (light receiving end surface 203a) by arranging and fixing the LED elements 201 on the surface thereof so as to be located at the center of the recess described above.

According to this configuration, the shape of the light receiving end surface 203a of the light guide body 203 makes it possible to take out the light radiated from the LED element 201 as substantially parallel light, and it is possible to improve the utilization efficiency of the generated light. Become.

As described above, the light source device 13 is configured by attaching a light source unit in which a plurality of LED elements 201 as a light source are arranged on a light receiving end surface 203a which is a light receiving portion provided on the end surface of the light guide body 203, and is configured from the LED element 201. The divergent light source is regarded as substantially parallel light by the lens shape of the light receiving end surface 203a of the light source end surface, and the inside of the light source 203 is guided (direction parallel to the drawing) as shown by an arrow, and the light source direction changing means 204. Therefore, the light is emitted toward the liquid crystal display panel 11 arranged substantially parallel to the light guide 203 (in the direction perpendicular to the front from the drawing). By optimizing the distribution (density) of the light flux direction changing means 204 according to the shape of the inside or the surface of the light guide body 203, the uniformity of the light flux incident on the liquid crystal display panel 11 can be controlled. The above-mentioned luminous flux direction changing means 204 provides a portion having a different refractive index, for example, in the shape of the surface of the light guide body 203 and the inside of the light guide body 203, so that the light flux propagating in the light guide body 203 can be transferred to the light guide body 203. It emits light toward the liquid crystal display panel 11 arranged substantially parallel to the light (in the direction perpendicular to the front from the drawing). At this time, it is practical if the relative brightness ratio when comparing the brightness of the center of the screen and the peripheral portion of the screen with the liquid crystal display panel 11 facing the center of the screen and the viewpoint at the same position as the diagonal dimension of the screen is 20% or more. There is no problem, and if it exceeds 30%, the characteristics will be even better.

Note that FIG. 8 is a cross-sectional layout diagram for explaining the configuration of the light source of the present embodiment for polarization conversion and its operation in the light source device 13 including the light guide body 203 and the LED element 201 described above. In FIG. 8, the light source device 13 includes, for example, a light guide body 203 provided with a light beam direction changing means 204 on a surface or inside formed of plastic or the like, an LED element 201 as a light source, a reflection sheet 205, and a retardation plate 216. It is composed of a lenticular lens or the like, and a liquid crystal display panel 11 having a light source light incident surface and a video light emitting surface having a polarizing plate is attached to the upper surface thereof.

A film or sheet-shaped reflective polarizing plate 49 is provided on the light incident surface (lower surface in the figure) of the liquid crystal display panel 11 facing the light source device 13, and one side of the natural luminous flux 210 emitted from the LED element 201 is provided. The polarization (for example, P wave) 212 is selectively reflected and reflected by the reflection sheet 205 provided on one surface (lower part of the figure) of the light guide 203 so as to be directed to the liquid crystal display panel 11 again. .. Therefore, a retardation plate 216 (λ / 4 plate) is provided between the reflective sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, and the light is reflected by the reflective sheet 205 and passed twice. As a result, the reflected light beam is converted from P-polarization to S-polarization, and the utilization efficiency of the light source light as the image light is improved. The image luminous flux whose light intensity is modulated by the image signal on the liquid crystal display panel 11 (arrow 213 in FIG. 8) is incident on the retroreflective member 2 and passes through the wind glass 105 after reflection as shown in FIG. It is possible to obtain a spatial floating image 3 which is a real image inside or outside the store (space).

FIG. 9 is a cross-sectional layout diagram for explaining the configuration and operation of the light source of the present embodiment for polarization conversion in the light source device 13 including the light guide body 203 and the LED element 201, similarly to FIG. Similarly, the light source device 13 also has a light guide body 203 provided with a light beam direction changing means 204 on or inside a surface formed of, for example, plastic, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 216, and a lenticular lens. As an image display element, a liquid crystal display panel 11 having a light source light incident surface and an image light emitting surface having a polarizing plate is attached to the upper surface thereof.

Further, a film or sheet-shaped reflective polarizing plate 49 is provided on the light incident surface (lower surface in the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and one side of the natural light beam 210 emitted from the LED element 201 is biased. The wave (for example, S wave) 211 is selectively reflected, reflected by the reflection sheet 205 provided on one surface (lower part of the figure) of the light guide body 203, and directed to the liquid crystal display panel 11 again. By providing a retardation plate 216 (λ / 4 plate) between the light guide sheet 205 and the light guide 203 or between the light guide 203 and the reflective polarizing plate 49, the light is reflected by the reflective sheet 205 and passed twice. The reflected light beam is converted from S-polarized light to P-polarized light, and the utilization efficiency of the light source light as image light is improved. The image luminous flux whose light intensity is modulated by the image signal on the liquid crystal display panel 11 (arrow 214 in FIG. 9) enters the retroreflective member 2 and, as shown in FIG. 1, passes through the wind glass 105 after reflection and is stored in the store. A spatial floating image 3 which is a real image can be obtained inside or outside the (space).

In the light source device 13 shown in FIGS. 8 and 9, the reflective polarizing plate 49 reflects the polarization component on one side together with the action of the reflective polarizing plate 49 provided on the light incident surface of the facing liquid crystal display panel 11. The theoretically obtained contrast ratio is obtained by multiplying the inverse of the cross transmittance of the reflective polarizing plate 49 by the inverse of the cross transmittance obtained by the two polarizing plates attached to the liquid crystal display panel 11. As a result, high contrast performance can be obtained. In fact, it was confirmed by experiments that the contrast performance of the displayed image was improved by 10 times or more. As a result, a high-quality image comparable to that of the self-luminous organic EL was obtained.

<Example of video display device (2)>
FIG. 10 shows another example of a specific configuration of the video display device 1. The light source device 13 of FIG. 10 is similar to the light source device of FIG. 12 and the like. The light source device 13 is configured by accommodating an LED, a collimator, a synthetic diffusion block, a light guide, and the like in a case such as plastic, and a liquid crystal display panel 11 is attached to the upper surface thereof. Further, on one side surface of the case of the light source device 13, LEDs (Light Emitting Diode) elements 14a and 14b, which are semiconductor light sources shown in FIG. 12 and the like, and an LED board 102 on which the control circuit thereof is mounted are attached, and an LED. A heat sink 103 (see FIG. 10), which is a member for cooling the heat generated by the LED elements 14a and 14b and the control circuit, is attached to the outer surface of the substrate 102 (see also FIGS. 12 and 13). ..

Further, the liquid crystal display panel frame attached to the upper surface of the case includes the liquid crystal display panel 11 attached to the frame, and the FPC (Flexible Printed Circuits: flexible wiring board) electrically connected to the liquid crystal display panel 11. ) 403 (see FIG. 10) and the like are attached and configured. That is, the liquid crystal display panel 11 which is an image display element, together with the LED elements 14a and 14b which are solid light sources, has the intensity of transmitted light based on the control signal from the control circuit (not shown here) constituting the electronic device. Is generated by modulating the display image.

<Example of video display device (3)>
Subsequently, another example of a specific configuration of the video display device 1 (example 3 of the display device) will be described with reference to FIG. The light source device of the image display device 1 converts the divergent light beam of the light from the LED (a mixture of P-polarized light and S-polarized light) into a substantially parallel light beam by the collimeter (colometer lens or LED collimator lens) 18, and is a reflective light guide. The reflective surface of 304 reflects toward the liquid crystal display panel 11. The reflected light is incident on the reflective polarizing plate 49 arranged between the liquid crystal display panel 11 and the reflective light guide 304. In the reflective polarizing plate 49, a specific polarization (for example, P polarization) is transmitted and incident on the liquid crystal display panel 11. The other polarization (for example, S polarization) is reflected by the reflection type polarizing plate and heads toward the reflection type light guide 304 again. The reflective polarizing plate 49 is installed with an inclination so as not to be perpendicular to the main ray of light from the reflecting surface of the reflective light guide body 304, and the main ray of light reflected by the reflective polarizing plate 49 is , Incident on the transmissive surface of the reflective light guide 304. The light incident on the transmission surface of the reflective light guide 304 passes through the back surface of the reflective light guide 304, passes through the retardation plate λ / 4 plate 270, and is reflected by the reflector 271. The light reflected by the reflector 271 passes through the λ / 4 plate 270 again and passes through the transmission surface of the reflective light guide 304. The light transmitted through the transmission surface of the reflective light guide 304 is incident on the reflective polarizing plate 49 again. At this time, since the light re-entering the reflective polarizing plate 49 passes through the λ / 4 plate 270 twice, the polarization is converted into the polarization (for example, P polarization) transmitted through the reflective polarizing plate 49. ing. Therefore, the light whose polarization has been converted passes through the reflective polarizing plate 49 and is incident on the liquid crystal display panel 11. Regarding the polarization design related to the polarization conversion, the polarization may be reversed (the S polarization and the P polarization are reversed) from the above description.

As a result, the light from the LED is aligned with a specific polarization (for example, P polarization), is incident on the liquid crystal display panel 11, is luminance-modulated according to the video signal, and displays the video on the panel surface. Similar to the above example, a plurality of LEDs constituting the light source are shown (however, because of the vertical cross section, only one is shown in FIG. 16), and these are mounted in a predetermined position with respect to the collimator 18. The collimator 18 is made of a translucent resin such as acrylic or glass, respectively. The collimator 18 may have a conical convex outer peripheral surface obtained by rotating a parabolic cross section. The top thereof may have a concave portion having a convex portion (that is, a convex lens surface) formed in the central portion thereof. Further, the central portion of the flat surface portion has a convex lens surface protruding outward (or a concave lens surface recessed inward). The paraboloid surface forming the conical outer peripheral surface of the collimator 18 is set within an angle range at which the light emitted from the LED in the peripheral direction can be totally reflected inside the paraboloid surface, or the reflective surface is set. It is formed.

The LEDs are arranged at predetermined positions on the surface of the LED substrate 102, which is the circuit board thereof. The LED substrate 102 is arranged and fixed to the collimator 18 so that the LEDs on the surface thereof are located at the center of the top of the conical convex shape (if the top has a recess, the recess). LED.

According to such a configuration, among the light radiated from the LED by the collimator 18, the light radiated from the central portion thereof is collected by the convex lens surface forming the outer shape of the collimator 18 to become parallel light. Further, the light emitted from the other portion toward the peripheral direction is reflected by the paraboloid forming the conical outer peripheral surface of the collimator 18, and is similarly condensed into parallel light. In other words, according to the collimator 18 in which a convex lens is formed in the central portion thereof and a paraboloid is formed in the peripheral portion thereof, almost all the light generated by the LED can be taken out as parallel light. It is possible to improve the utilization efficiency of the light.

The above configuration is the same as that of the light source device of the video display device shown in FIGS. 12, 13, and the like. Further, the light converted into substantially parallel light by the collimator 18 shown in FIG. 11 is reflected by the reflective light guide 304. Of the light, the light of a specific polarization is transmitted through the reflection type polarizing plate 49 by the action of the reflection type polarizing plate 49, and the light of the other polarization reflected by the action of the reflection type polarizing plate 49 is again a light guide. It is transparent to 304. The light is reflected by the reflector 271 at a position opposite to that of the liquid crystal display panel 11 with respect to the reflective light guide 304. At this time, the light is polarized by passing through the retardation plate λ / 4 plate 270 twice. The light reflected by the reflector 271 passes through the light guide 304 again and is incident on the reflective polarizing plate 49 provided on the opposite surface. Since the incident light has undergone polarization conversion, it passes through the reflective polarizing plate 49 and is incident on the liquid crystal display panel 11 with the polarization directions aligned. As a result, all the light from the light source can be used, so that the geometrical optics utilization efficiency of the light is doubled. Further, since the degree of polarization (extinguishing ratio) of the reflective polarizing plate is also added to the extinguishing ratio of the entire system, the contrast ratio of the entire display device is significantly improved by using the light source device of this embodiment. By adjusting the surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271, the reflection diffusion angle of light on each reflective surface can be adjusted. The surface roughness of the reflective surface of the reflective light guide 304 and the surface roughness of the reflector 271 may be adjusted for each design so that the uniformity of the light incident on the liquid crystal display panel 11 becomes more suitable.

The λ / 4 plate 270, which is the retardation plate of FIG. 11, does not necessarily have a phase difference of λ / 4 with respect to the polarization vertically incident on the λ / 4 plate 270. In the configuration of FIG. 11, a phase difference plate whose phase changes by 90 ° (λ / 2) by passing the polarized light twice may be used. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarized light.

The light emitted from the liquid crystal display panel 11 has the same diffusion characteristics in the conventional TV set in both the horizontal direction of the screen (displayed on the X-axis in FIG. 16A) and the vertical direction of the screen (displayed on the Y-axis in FIG. 16B). have. On the other hand, the diffusion characteristic of the luminous flux emitted from the liquid crystal display panel 11 of this embodiment has a viewing angle of 13 such that the brightness is 50% of the front view (angle 0 degree) as shown in Example 1 of FIG. By setting the degree, it becomes 1/5 of the conventional 62 degrees. Similarly, the viewing angle in the vertical direction is uneven up and down, and the reflection angle of the reflective light guide and the area of the reflecting surface are optimized so that the upper viewing angle is suppressed to about 1/3 of the lower viewing angle. do. As a result, the amount of image light in the monitoring direction is significantly improved as compared with the conventional liquid crystal TV, and the brightness is 50 times or more.

Further, if the viewing angle characteristic shown in Example 2 of FIG. 16 is used, the brightness becomes 50% of the front view (angle 0 degree). By setting the viewing angle to 5 degrees, it becomes 1/12 of the conventional 62 degrees. .. Similarly, the viewing angle in the vertical direction is set to be even in the vertical direction, and the reflection angle of the reflective light guide and the area of the reflecting surface are optimized so that the viewing angle is suppressed to about 1/12 of the conventional one. As a result, the amount of video light in the monitoring direction is significantly improved as compared with the conventional liquid crystal TV, and the brightness is 100 times or more. As described above, by narrowing the viewing angle, the amount of light flux toward the monitoring direction can be concentrated, so that the efficiency of light utilization is greatly improved. As a result, even if a conventional liquid crystal display panel for TV is used, it is possible to realize a significant improvement in brightness with the same power consumption by controlling the light diffusion characteristics of the light source device, and the spatial floating image for the outdoors can be realized. The image display device 1 corresponding to the display system can be used.

Return to FIG. As a basic configuration, as shown in FIG. 11, a light beam having a narrow-angle directional characteristic is incident on the liquid crystal display panel 11 by a light source device, and the brightness is modulated according to a video signal so as to be on the screen of the liquid crystal display panel 11. The spatial floating image 3 obtained by reflecting the displayed image information by the retroreflective member 2 is displayed outdoors or indoors via the wind glass 105.

<Example of light source device 13 (1)>
Subsequently, the configuration of the optical system such as the light source device housed in the housing 106 (see FIG. 6B) will be described in detail with reference to FIGS. 13 (A) and 13 (B) together with FIG. 12.

FIG. 12 shows LED elements 14a and 14b constituting the light source, which are attached to the LED collimator 15 at a predetermined position. Each of the LED collimators 15 is made of a translucent resin such as acrylic. As shown in FIG. 13B, the LED collimator 15 has a conical convex outer peripheral surface 156 obtained by rotating a parabolic cross section, and at the top thereof, a convex portion (convex portion) at the center thereof. That is, it has a concave portion 153 forming a convex lens surface) 157. Further, the central portion of the flat surface portion has a convex lens surface protruding outward (or a concave lens surface recessed inward) 154. The paraboloid surface forming the conical outer peripheral surface 156 of the LED collimator 15 is set within an angle range within which the light emitted from the LED elements 14a and 14b in the peripheral direction can be totally reflected inside. Or, a reflective surface is formed.

Further, the LED elements 14a and 14b are respectively arranged at predetermined positions on the surface of the LED substrate 102 which is the circuit board thereof. The LED substrate 102 is arranged and fixed to the LED collimator 15 so that the LED elements 14a or 14b on the surface thereof are respectively located at the center of the recess 153.

According to such a configuration, among the light radiated from the LED element 14a or 14b by the above-mentioned LED collimator 15, the light radiated upward (to the right in FIG. 13B) from the central portion thereof. Is focused by the two convex lens surfaces 157 and 154 that form the outer shape of the LED collimator 15 to form parallel light. Further, the light emitted from the other portion toward the peripheral direction is reflected by the paraboloid forming the conical outer peripheral surface 156 of the LED collimator 15, and is similarly condensed into parallel light. In other words, according to the LED collimator 15 in which a convex lens is formed in the central portion thereof and a paraboloid is formed in the peripheral portion thereof, almost all the light generated by the LED element 14a or 14b is taken out as parallel light. It becomes possible to improve the utilization efficiency of the generated light.

As shown in FIG. 13, a polarization conversion element 21 is provided on the light emitting side of the LED collimator 15. As is clear from FIG. 13, the polarization conversion element 21 has a columnar (hereinafter, parallelogram) translucent member having a parallelogram cross section and a columnar (hereinafter, triangular column) having a triangular cross section. ) Is combined with the translucent member, and a plurality of pieces are arranged in an array in parallel with the plane orthogonal to the optical axis of the parallel light from the LED collimator 15. Further, at the interface between the adjacent translucent members arranged in an array, a polarizing beam splitter (hereinafter abbreviated as "PBS film") 211 and a reflective film 212 are alternately provided. Further, a λ / 2 phase plate 215 is provided on the exit surface where the light incident on the polarization conversion element 21 and transmitted through the PBS film 211 is emitted.

Further, a rectangular synthetic diffusion block 16 shown in FIG. 13A is provided on the emission surface of the polarization conversion element 21. That is, the light emitted from the LED element 14a or 14b becomes parallel light by the action of the LED collimator 15 and enters the synthetic diffusion block 16, diffused by the texture 161 on the emitting side, and then reaches the light guide body 17. Ru.

The light guide body 17 is a member formed of a translucent resin such as acrylic into a rod shape having a substantially triangular cross section (see FIG. 13 (B)), and as is clear from FIG. 12, it is synthesized. A light guide body light incident portion (plane) 171 facing the emission surface of the diffusion block 16 via the first diffuser plate 18a, a light guide body light reflection portion (plane) 172 forming a slope, and a second diffuser plate 18b. A light guide light emitting unit (plane) 173 facing the liquid crystal display panel 11 which is an image display element is provided.

As shown in FIG. 13 (B), which is a partially enlarged view thereof, a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately arranged on the light reflecting portion (plane) 172 of the light guide body 17. It is formed in a serrated shape. Then, the reflecting surface 172a (a line segment rising to the right in the figure) forms αn (n: a natural number, for example, 1 to 130 in this example) with respect to the horizontal plane indicated by the alternate long and short dash line in the figure. As an example, here, αn is set to 43 degrees or less (however, 0 degrees or more).

The light guide body incident portion (plane) 171 is formed in a curved convex shape inclined toward the light source side. According to this, the parallel light from the emission surface of the synthetic diffusion block 16 is diffused and incident through the first diffusion plate 18a, and as is clear from FIG. 12, the light guide body incident portion (plane) 171 It reaches the light guide body light reflecting portion (plane) 172 while being slightly bent (deflected) upward, and is reflected here to reach the liquid crystal display panel 11 provided on the upper exit surface of FIG.

According to the image display device 1 described in detail above, it is possible to further improve the light utilization efficiency and its uniform lighting characteristics, and at the same time, to manufacture the image display device 1 in a small size and at low cost including a modularized S polarized wave light source device. It will be possible. In the above description, the polarization conversion element 21 is attached after the LED collimator 15, but the present invention is not limited thereto, and the same can be applied by providing the polarization conversion element 21 in the optical path leading to the liquid crystal display panel 11. Action / effect can be obtained.

A large number of reflecting surfaces 172a and connecting surfaces 172b are alternately formed in a sawtooth shape on the light guide body light reflecting portion (surface) 172, and the illumination light beam is totally reflected on each reflecting surface 172a. Further upward, a narrow-angle diffuser plate (not shown) is provided on the light emitting portion (plane) 173 of the light guide body, and is incident on the optical direction conversion panel 54 that controls the directivity characteristics as a substantially parallel diffused light beam. Then, the light is incident on the liquid crystal display panel 11 from an oblique direction. In this embodiment, the light direction conversion panel 54 is provided between the light guide body emission surface 173 and the liquid crystal display panel 11, but the same effect can be obtained by providing the light direction conversion panel 54 on the emission surface of the liquid crystal display panel 11.

<Example of light source device 13 (2)>
FIG. 14 shows another example of the configuration of the optical system such as the light source device 13. Similar to the example shown in FIG. 13, a plurality of (two in this example) LED elements 14a and 14b constituting the light source are shown, and these are attached to the LED collimator 15 at a predetermined position. There is. Each of the LED collimators 15 is made of a translucent resin such as acrylic. Then, as in the example shown in FIG. 13, this LED collimator 15 has a conical convex outer peripheral surface 156 obtained by rotating a parabolic cross section, and at the top thereof, a convex portion (that is, a convex portion) is formed at the center thereof. , Convex lens surface) It has a recess 153 forming 157. Further, the central portion of the flat surface portion has a convex lens surface protruding outward (or a concave lens surface recessed inward) 154. The paraboloid surface forming the conical outer peripheral surface 156 of the LED collimator 15 is set within an angle range at which the light emitted from the LED element 14a in the peripheral direction can be totally reflected inside the paraboloid surface. , A reflective surface is formed.

Further, the LED elements 14a and 14b are respectively arranged at predetermined positions on the surface of the LED substrate 102, which is the circuit board thereof. The LED substrate 102 is arranged and fixed to the LED collimator 15 so that the LED elements 14a or 14b on the surface thereof are respectively located at the center of the recess 153.

According to such a configuration, among the light radiated from the LED element 14a or 14b by the LED collimator 15 described above, the light radiated upward (to the right in the figure) from the central portion thereof is particularly the LED collimator. The two convex lens surfaces 157 and 154 forming the outer shape of 15 are focused to form parallel light. Further, the light emitted from the other portion toward the peripheral direction is reflected by the paraboloid forming the conical outer peripheral surface 156 of the LED collimator 15, and is similarly condensed into parallel light. In other words, according to the LED collimator 15 in which a convex lens is formed in the central portion thereof and a paraboloid is formed in the peripheral portion thereof, almost all the light generated by the LED element 14a or 14b is taken out as parallel light. It becomes possible to improve the utilization efficiency of the generated light.

A light guide body 170 is provided on the light emitting side of the LED collimator 15 via the first diffusion plate 18a. The light guide body 170 is a member formed of a translucent resin such as acrylic into a rod shape having a substantially triangular cross section (see FIG. 14 (A)), and as is clear from FIG. 14 (A). In addition, an incident portion (plane) 171 of the light guide body 170 facing the emission surface of the synthetic diffusion block 16 via the first diffuser plate 18a, a light light reflecting portion (plane) 172 forming a slope, and reflection. It includes a light guide body light emitting unit (plane) 173 facing the liquid crystal display panel 11 which is an image display element via the type polarizing plate 200.

For example, if a reflective polarizing plate 200 having a property of reflecting P-polarized light (transmitting S-polarized light) is selected, the reflective polarizing plate 200 reflects P-polarized light among the natural light emitted from the LED elements 14a and 14b which are light sources. It passes through the λ / 4 plate 172c provided in the light light reflecting unit 172 of the light guide body shown in 14 (B), is reflected by the reflecting surface 172d, and is converted into S polarization by passing through the λ / 4 plate 172c again. All the light rays incident on the liquid crystal display panel 11 are unified to S polarization.

Similarly, if a reflective polarizing plate 200 having a characteristic of reflecting S-polarization (P-polarization is transmitted) is selected, S-polarization is reflected among the natural light emitted from the LED elements 14a and 14b which are light sources, and the figure shows. It passes through the λ / 4 plate 172c provided in the light guide body light reflecting unit 172 shown in 14 (B), is reflected by the reflecting surface 172d, and is converted into P-polarized light by passing through the λ / 4 plate 172c again. All the light rays incident on the liquid crystal display panel 52 are unified to P polarization. Polarization conversion can be realized even with the above-mentioned configuration.

<Example of light source device 13 (3)>
Another example of the configuration of an optical system such as a light source device will be described with reference to FIG. In the third example, as shown in FIG. 11, the divergent luminous flux of natural light (a mixture of P-polarized light and S-polarized light) from the LED substrate 102 is converted into a substantially parallel luminous flux by the LED collimator lens 18, and the reflective light guide body 304 is used. It reflects toward the liquid crystal display panel 11. The reflected light is incident on the reflective polarizing plate 49 arranged between the liquid crystal display panel 11 and the reflective light guide 304. A reflective plate 271 is arranged so that a specific polarization (for example, S polarization) is reflected by the reflective polarizing plate 49, passes through a surface connecting the reflective surfaces of the light guide 304, and faces the opposite surface of the light guide 304. It is reflected by and transmitted through the phase plate (λ / 4 wavelength plate) 270 twice to be polarized, transmitted through the light guide and the reflective polarizing plate, incident on the liquid crystal display panel 11, and modulated by video light. At this time, by matching the specific polarization and the polarization plane that has been polarized, the efficiency of light utilization is doubled, and the degree of polarization (extinguishing ratio) of the reflective polarizing plate is also added to the extinguishing ratio of the entire system. By using the light source device of this embodiment, the contrast ratio of the information display system is significantly improved.

As a result, the natural light from the LED is aligned with a specific polarization (for example, P polarization). Similar to the above example, a plurality of LEDs constituting the light source are provided (however, only one is shown in FIG. 12 because of the vertical cross section), and these are attached to the LED collimator lens 18 at a predetermined position. There is. The LED collimator lens 18 is made of a translucent resin such as acrylic or glass, respectively. The LED collimator lens 18 has a conical convex outer peripheral surface obtained by rotating a parabolic cross section, and has a concave portion having a convex portion (that is, a convex lens surface) formed at the center thereof at the top thereof. .. Further, the central portion of the flat surface portion has a convex lens surface protruding outward (or a concave lens surface recessed inward). The radial surface forming the conical outer peripheral surface of the LED collimator lens 18 is set within an angle range within which the light emitted from the LED collimator lens 18 in the peripheral direction can be totally reflected. Alternatively, a reflective surface is formed.

Further, the LEDs are arranged at predetermined positions on the surface of the LED substrate 102, which is the circuit board thereof. The LED substrate 102 is fixed to the LED collimator lens 18 by arranging and fixing LEDs on the surface thereof so as to be located at the center of the recess.

According to such a configuration, among the light radiated from the LED by the LED collimator lens 18, the light radiated from the central portion thereof is collected by the two convex lens surfaces forming the outer shape of the LED collimator lens 18. Becomes parallel light. Further, the light emitted from the other portion toward the peripheral direction is reflected by the paraboloid forming the conical outer peripheral surface of the LED collimator lens 18, and is similarly condensed to become parallel light. In other words, according to the LED collimator lens 18 having a convex lens formed in the center thereof and a paraboloid formed in the peripheral portion thereof, almost all the light generated by the LED can be taken out as parallel light. , It is possible to improve the utilization efficiency of the generated light.

<Example of video display device (4)>
Further, another example (Example 4 of the display device) regarding the configuration of the optical system such as the light source device of the display device will be described with reference to FIG. This is a configuration example in which a diffusion sheet is used instead of the reflective light guide body 304 in the light source device of Example 3 of the display device. Specifically, on the light emitting side of the LED collimator lens 18, two optical sheets that convert the diffusion characteristics in the vertical direction and the horizontal direction (not shown in the front-back direction in the figure) in the drawing are used (optical sheet 207A and the optical sheet 207A and the optical sheet 207A. The light from the optical sheet 207B) and the LED collimator lens 18 is incidented between the two optical sheets (diffusing sheets). This optical sheet may be one sheet instead of two sheets. In the case of a single sheet configuration, the vertical and horizontal diffusion characteristics are adjusted by the fine shapes of the front and back surfaces of one optical sheet. Further, a plurality of diffusion sheets may be used to share the action. Here, in the example of FIG. 17, regarding the reflection / diffusion characteristics due to the front surface shape and the back surface shape of the optical sheet 207A and the optical sheet 207B, the number of LEDs and the number of LEDs are set so that the surface density of the light flux emitted from the liquid crystal display panel 11 becomes uniform. The divergence angle from the LED substrate (optical element) 102 and the optical specifications of the LED collimator lens 18 may be optimally designed as design parameters. That is, the diffusion characteristics are adjusted by the surface shapes of a plurality of diffusion sheets instead of the light guide. In the example of FIG. 17, the polarization conversion is performed in the same manner as in Example 3 of the display device described above. That is, in the example of FIG. 17, the reflective polarizing plate 49 may be configured to have a characteristic of reflecting S-polarized light (transmitting P-polarized light). In that case, of the light emitted from the LED as the light source, the P-polarized light is transmitted, and the transmitted light is incident on the liquid crystal display panel 11. Of the light emitted from the LED as the light source, the S-polarized light is reflected, and the reflected light passes through the retardation plate 270 shown in FIG. The light that has passed through the retardation plate 270 is reflected by the reflector plate 271. The light reflected by the reflector 271 is converted into P-polarized light by passing through the retardation plate 270 again. The polarization-converted light passes through the reflective polarizing plate 49 and is incident on the liquid crystal display panel 11. The λ / 4 plate 270, which is the retardation plate of FIG. 17, does not necessarily have a phase difference of λ / 4 with respect to the polarization vertically incident on the λ / 4 plate 270. In the configuration of FIG. 17, any phase difference plate may be used as long as the phase is changed by 90 ° (λ / 2) by passing the polarized light twice. The thickness of the retardation plate may be adjusted according to the incident angle distribution of the polarized light. It should be noted that also in FIG. 17, regarding the polarization design related to the polarization conversion, the polarization may be reversed (the S polarization and the P polarization are reversed) from the above description.

<Example of light source device 13 (5)>
Another example of the configuration of the optical system of the light source device 13 will be described with reference to FIG. As shown in FIG. 18C, a polarization conversion element 21 is arranged on the light emitting side of the LED collimator lens 18. Then, the natural light from the LED element 14c is aligned with a specific polarization to be incident on the optical element 81 that controls the diffusion characteristics, and the diffusion characteristics in the vertical direction and the horizontal direction (not shown in the front-back direction in the figure) are controlled. The light distribution characteristics toward the reflective surface of the reflective light guide 220 are optimized. As shown in FIG. 18B, an uneven pattern 222 is provided on the surface of the reflective light guide 220, and is reflected toward an image display device (not shown) arranged on the facing surface of the reflective light guide 220. And obtain the desired diffusion characteristics. Since the placement accuracy of the LED element 14c and the LED collimator lens 18 of the light source greatly affects the efficiency of the light source, the accuracy of the optical axis usually needs to be about 50 μm. As a measure to reduce the mounting accuracy, the drop in mounting accuracy was reduced by using a plurality of or a single unit as the light source unit 223 structure in which several LED elements 14c and the LED collimator lens 18 are integrated in the light source device.

In the embodiment shown in FIGS. 18A, 18B, and 18C, a plurality of light source units 223 in which the LED element 14c and the LED collimator lens 18 are integrated are incorporated at both ends of the reflective light guide body 220 in the long side direction. This (three on each side in the embodiment of FIG. 18) realizes uniform brightness of the light source device. A plurality of concave-convex patterns 222 substantially parallel to the light source unit are formed on the reflective surface 220a of the reflective light guide body 220, and even in one concave-convex pattern 222, the surface thereof forms a polyhedron so that the amount of light incident on the image display device 1 Can be controlled with high precision. In this embodiment, the shape of the reflective surface is described as the uneven pattern 222, but even if the pattern has triangular surfaces, corrugated surfaces, etc. arranged regularly or irregularly, the reflective light guide body 220 is directed toward the image display device 1 depending on the surface shape. Needless to say, if the light distribution pattern is controlled, it conflicts with the present invention. Further, a light-shielding wall 224 is provided on the side surface of the reflective light guide 220 so that the light controlled by the LED collimator lens 18 does not leak to the outside from the light source device 13, and the LED element 14c has heat dissipation by the metal base 225. The design should be enhanced.

<Lenticular sheet>
Hereinafter, the operation of the lenticular lens that controls the diffusion characteristic of the light emitted from the image display device 1 will be described. By optimizing the lens shape of the lenticular lens, it is possible to efficiently obtain the spatially floating image 3 emitted from the above-mentioned image display device 1 and transmitted or reflected through the wind glass 105. That is, for the image light from the image display device 1, two lenticular lenses are combined, or microlens arrays are arranged in a matrix to provide a sheet for controlling the diffusion characteristics, and in the X-axis and Y-axis directions. The brightness (relative brightness) of the image light can be controlled according to the reflection angle (0 degrees in the vertical direction). In this embodiment, such a lenticular lens can make the luminance characteristic in the vertical direction steeper as shown in FIG. 16B as compared with the conventional case. Further, the brightness (relative brightness) of light due to reflection or diffusion can be increased by changing the balance of the directional characteristics in the vertical direction (positive / negative direction of the Y axis). Due to these effects, the image light has a narrow diffusion angle (high straightness) and only a specific polarization component, like the image light from a surface-emitting laser image source, and a conventional image display device was used. In some cases, the ghost image generated by the retroreflective member can be suppressed, and the space floating image due to retroreflective can be efficiently controlled to reach the viewer's eyes.

Further, by each of the above-mentioned light source devices, the X-axis direction and the Y-axis with respect to the emission light diffusion characteristics (denoted as conventional in the figure) from the general liquid crystal display panel 11 shown in FIGS. 16 (A) and 16 (B). It is possible to realize a directional characteristic with a significantly narrow angle in both directions. This makes it possible to realize an image display device that emits light having a specific polarization that emits an image luminous flux that is almost parallel to a specific direction.

FIG. 15 shows an example of the characteristics of the lenticular lens used in this embodiment. In this example, in particular, the characteristic in the X direction (vertical direction) is shown. In the characteristic O, the peak in the light emission direction is at an angle of about 30 degrees upward from the vertical direction (0 degrees) and is vertically symmetrical. It shows the brightness characteristics. Further, the characteristics A and B in FIG. 15 further show an example of a characteristic in which the image light above the peak luminance is condensed at around 30 degrees to increase the luminance (relative luminance). Therefore, in these characteristics A and B, the brightness (relative brightness) of light is sharply reduced as compared with the characteristic O at an angle exceeding 30 degrees.

That is, according to the above-mentioned optical system including the lenticular lens, when the image light beam from the image display device 1 is incident on the retroreflective member 2, the emission angle of the image light aligned in a narrow angle by the light source devices 13 and 230 is The viewing angle can be controlled, and the degree of freedom in installing the retroreflective member 2 can be greatly improved. As a result, the degree of freedom of the relationship between the image formation positions of the spatial floating image 3 that reflects or transmits the wind glass 105 and forms an image at a desired position can be greatly improved. As a result, it is possible to efficiently reach the eyes of the viewer outdoors or indoors as light having 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 is possible to realize a spatial floating video display system with low power consumption.

Although various examples have been described in detail above, however, the present invention is not limited to the above-mentioned examples, and includes various modifications. For example, the above-described embodiment describes the entire system in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

In the technique according to the present embodiment, by displaying the spatially floating image in a state where the spatially floating image is displayed in a state of being spatially suspended with high resolution and high brightness, for example, the user can operate the image without feeling anxiety about contact infection of an infectious disease. to enable. By using the technique according to this embodiment for a system used by an unspecified number of users, it is possible to reduce the risk of contact infection of infectious diseases and provide a non-contact user interface that can be used without feeling anxiety. .. This will contribute to "3 Health and Welfare for All" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

Further, in the technique according to the present embodiment, the emission angle of the emitted image light is made small, and by aligning the emission angle with a specific polarization, only the normal reflected light is efficiently reflected by the retroreflective member. It is highly efficient and makes it possible to obtain bright and clear floating images in space. According to the technique according to the present embodiment, it is possible to provide a highly usable non-contact user interface capable of significantly reducing power consumption. This will contribute to the Sustainable Development Goals (SDGs) advocated by the United Nations, "Let's lay the foundation for 9 industries and technological innovation," and "11 Create a city where people can continue to live."

Further, the technique according to the present embodiment makes it possible to form a spatial floating image by image light having high directivity (straightness). The technique according to this embodiment has high directivity even when displaying images that require high security at bank ATMs, ticket vending machines at stations, etc., or images that are highly concealed and that the person facing the user wants to conceal. By displaying the image light, it is possible to provide a non-contact user interface with less risk of being peeped into the floating image in space other than the user. This will contribute to the "11 Sustainable Development Goals" (SDGs: Sustainable Development Goals) advocated by the United Nations.

1: Video display device 1a: Video display unit 1b: Video control unit 1c: Video signal reception unit 1d: Receiving antenna 2: Retroreflective member 2a: Retroreflective unit 3: Spatial floating image 11: Liquid crystal display panel 12: Absorption-type polarization Plate 13: Light source device 13a: Light source device 14a to c: LED element 15: LED collimeter 16: Synthetic diffusion block 17: Light guide body 18: LED collimeter lens 18a: First diffusion plate 18b: Second diffusion plate 21: λ / 4 plates (polarization conversion element)
22: 1st light-shielding member 23: 2nd light-shielding member 24: 3rd light-shielding member 25: 4th light-shielding member 30: Arrow 49: Reflective polarizing plate 50: Protective cover 52: Liquid crystal display panel 54: Optical direction conversion panel 81: Optical element 100: Transparent member 100a: Window portion 100b: Light-shielding member 101: Polarization separation member 102: LED substrate 103: Heat sink 105: Wind glass 106: Housing 107: Optical element 112: Absorption-type polarizing plate 153: Recessed 154: Convex lens Surface 156: Outer peripheral surface 157: Convex lens surface 161: Texture 170: Light guide body 172: Light guide body light reflection unit 172a: Reflection surface 172b: Connecting surface 172c: λ / 4 plate 172d: Reflection surface 173: Light guide body emission surface 200: Reflective polarizing plate 201: LED element 202: LED substrate 203: Light guide body 203a: Light receiving end face 204: Light emitting direction changing means 205: Reflective sheet 206: Reflective polarizing plate 207: Optical sheet 210: Natural light beam 211: PBS Film 212: Reflective film 215: λ / 2 Phase plate 216: Phase difference plate 220: Reflective light guide body 220a: Reflective surface 222: Concavo-convex pattern 223: Light source unit 230: Light source device 270: Phase difference plate 271: Reflective plate 272 : Reflective surface 304: Reflective light guide body 400: Reflective mirror 1027: Optical element Polarization conversion element 2135: Two phase plate 220: Light guide body 222: Concavo-convex pattern 223: Light source unit 224: Light shielding wall 225: Base G1 to G6: 1st ghost image to 6th ghost image R1: Normal image

Claims (36)

A space floating image display device that forms a space floating image.
A liquid crystal display panel as an image source,
A light source device that supplies light in a specific polarization direction to the liquid crystal display panel,
A retroreflective member with a retardation plate on the retroreflective surface is provided.
A polarization separating member is provided in the space connecting the liquid crystal display panel and the retroreflective member.
The polarization separating member once transmits the image light of a specific polarization from the liquid crystal display panel toward the retroreflective member, and is polarized by the retroreflective member to be converted into the other polarization. A spatial floating image display device that displays a spatial floating image that is a real image on the opposite side of the image source in a transparent member that is reflected by a polarization separating member and through which image light of the specific polarization passes. The space floating image display device according to claim 1.
A spatial floating image display device arranged so that the image display surface of the liquid crystal display panel and the retroreflection surface of the retroreflection member are parallel to each other. The space floating image display device according to claim 2.
The space floating image display device is a position where the display position of the space floating image is determined according to the distance between the liquid crystal display panel and the polarization separating member. The space floating image display device according to claim 1.
The polarization separating member is a spatial floating image display device formed of a reflective polarizing plate or a metal multilayer film that reflects a specific polarization. The space floating image display device according to claim 1.
A spatial floating image display device provided with an absorption-type polarizing plate on at least one surface of the transparent member. The space floating image display device according to claim 1.
The transparent member is a space floating image display device in which a portion through which the image light passes is formed of a transparent body, and a portion through which the image light does not pass is a light-shielding member. The space floating image display device according to claim 1.
A spatial floating image display device in which an antireflection film is provided on the image display surface of the liquid crystal display panel as the image source, and the reflected light is absorbed by the absorption type polarizing plate provided on the liquid crystal display panel. A space floating image display device that forms a space floating image.
The video display device is
A liquid crystal display panel as an image source and
The liquid crystal display panel includes a light source device that supplies light in a specific polarization direction, and a retroreflective member having a retroreflective surface provided with a retardation plate.
A polarization separating member is provided in the space connecting the liquid crystal display panel and the retroreflective member.
The polarization separating member once transmits the image light of a specific polarization from the liquid crystal display panel toward the retroreflective member, and is polarized by the retroreflective member to be converted into the other polarization. A spatial floating image, which is a real image, is displayed on the side opposite to the image source in the transparent member provided in the opening through which the image light of the specific polarization passes, which is reflected by the polarization separating member.
A spatial floating image display device in which the retroreflective member is arranged at an angle with respect to the liquid crystal display panel and is arranged at a position away from the opening through which the retroreflective image light passes to prevent the incident of external light. The space floating image display device according to claim 8.
A spatial floating image display device having a configuration in which the light source device is provided at a position away from the opening through which the retroreflective image light passes or at a position where the image light emitted from the liquid crystal display panel cannot be visually recognized from the opening. The space floating image display device according to claim 8.
The spatial floating image emitted from the opening is configured to be temporarily reflected by the reflection mirror, and the position and angle of the spatial floating image obtained by setting the angle of the reflective mirror to a desired angle with respect to the plane of the opening. A space floating image display device that can be changed. The space floating image display device according to claim 8.
The reflection mirror that reflects the spatial floating image emitted from the opening is a spatial floating image display device having a characteristic of high reflectance of a specific polarization. The space floating image display device according to any one of claims 1 to 11.
The image displayed on the liquid crystal display panel as the image source is a space floating image display device that corrects the distortion of the image generated in the optical system forming the space floating image. A space floating image display device that forms a space floating image.
A liquid crystal display panel, a light source device for supplying light in a specific polarization direction to the liquid crystal display panel, and a retroreflective member are provided.
In the space connecting the liquid crystal display panel and the retroreflective member, a light-shielding member for blocking the incident of video light having a divergence angle exceeding a specific angle from the liquid crystal display panel onto the retroreflective member is arranged.
The surface roughness of the reflective surface of the retroreflective member is set so that the ratio of the blur amount l of the spatial floating image and the pixel size L of the image display device is 40% or less.
The light source device includes a point-shaped or planar light source, an optical means for reducing the emission angle of light from the light source, and an optical means.
A polarization conversion means for aligning the light from the light source with the polarization in a specific direction,
A light guide body having a reflecting surface propagating to the image display device is provided.
Adjusted according to the shape and surface roughness of the reflective surface provided on the light guide,
A space floating image display device that reflects an image luminous flux having a narrow divergence angle from the liquid crystal display panel on the retroreflective member to form the space floating image in the air. The space floating image display device according to claim 13.
The surface roughness of the reflective surface of the retroreflective member is set to 160 nm or less.
The light guide is arranged so as to face the liquid crystal display panel, and a reflective surface for reflecting light from the light source toward the liquid crystal display panel is provided inside or on the surface of the light guide. Propagate light to the display panel
The liquid crystal display panel modulates the light intensity according to the video signal.
A spatial floating image display device that reflects an image luminous flux having a narrow divergence angle from the liquid crystal display panel on a retroreflective member to form the spatial floating image in the air. In the space floating image display device according to claim 13,
The light source device has a part or all of the light emission divergence angle of the light beam so that the light emission divergence angle of the liquid crystal display panel constituting the image display device is within ± 30 degrees, and the shape of the reflection surface of the light source device. A spatial floating image display device that is controlled by surface roughness. In the space floating image display device according to claim 13,
The light source device adjusts a part or all of the light emission divergence angle of the light beam according to the shape and surface roughness of the reflection surface of the light source device so that the light emission divergence angle of the liquid crystal display panel is within ± 15 degrees. Spatial floating image display device. In the space floating image display device according to claim 13,
The light source device has a part or all of the divergence angle of the light beam so that the divergence angle of the light beam of the liquid crystal display panel is different from the horizontal divergence angle and the vertical divergence angle. A space floating image display device controlled by. In the space floating image display device according to claim 13,
The light source device has a contrast performance obtained by multiplying the contrast obtained by the characteristics of the polarizing plate provided on the light incident surface and the light emitting surface of the liquid crystal display panel by the inverse of the efficiency of the polarization conversion in the polarization conversion means. , Space floating image display device. In the space floating image display device according to claim 13,
The image light from the liquid crystal display panel is once reflected by the reflective polarizing plate and arranged so as to be incident on the retroreflective member.
A retardation plate is provided on the image light incident surface of the retroreflective member.
A spatially floating image display device that converts the polarization of the image light into the other polarization by passing the image light twice through the retardation plate and allows the image light to pass through the reflective polarizing plate. In the space floating image display device according to claim 19,
In the light source device, the contrast obtained by the characteristics of the polarizing plates provided on the light incident surface and the light emitting surface of the liquid crystal display panel is the inverse of the efficiency of the polarization conversion in the polarization converting means and the cross transmission of the reflective polarizing plate. A spatially floating image display device that has contrast performance that is multiplied by the inverse of the rate. A space floating image display device that forms a space floating image.
A liquid crystal display panel, a light source device for supplying light in a specific polarization direction to the liquid crystal display panel, and a retroreflective member are provided.
In the space connecting the liquid crystal display panel and the retroreflective member, a light-shielding member for blocking the incident of video light having a divergence angle exceeding a specific angle from the liquid crystal display panel on the retroreflective member is arranged.
The surface roughness of the reflective surface of the retroreflective member is set so that the ratio of the blur amount l of the spatial floating image and the pixel size L of the image display device is 40% or less.
The light source device includes a point-shaped or planar light source, an optical means for reducing the divergence angle of light from the light source, a polarization conversion means for aligning the light from the light source with polarization in a specific direction, and the image display device. With a light source having a reflective surface propagating to
The light guide is arranged so as to face the liquid crystal display panel.
A reflective surface is provided inside or on the surface of the light guide to reflect light from the light source toward the liquid crystal display panel, and light in a specific polarization direction reflected by the reflective polarizing plate is reflected by the light guide. A phase difference arranged on the upper surface of the reflector, which is transmitted through a surface connecting adjacent reflective surfaces of the body and reflected by a reflector provided on a surface opposite to the surface of the light guide that is in contact with the liquid crystal display panel. By passing the plate twice, the light is converted into a polarization, and the light is converted into a polarization that passes through the reflective polarizing plate and passed through the light guide body to propagate the light to the image display device.
The liquid crystal display panel modulates the light intensity according to the video signal.
The light source device controls a part or all of the divergence angle of the light flux incident on the liquid crystal display panel from the light source by the shape and surface roughness of the reflective surface provided on the light source device.
A spatial floating image display device that forms the spatial floating image in the air by reflecting an image luminous flux having a narrow divergence angle from the liquid crystal display panel on a retroreflective member. A space floating image display device that forms a space floating image.
A liquid crystal display panel, a light source device for supplying light in a specific polarization direction to the liquid crystal display panel, and a retroreflective member are provided.
In the space connecting the liquid crystal display panel and the retroreflective member, a light-shielding member for blocking the incident of video light having a divergence angle exceeding a specific angle from the liquid crystal display panel on the retroreflective member is arranged.
The surface roughness of the reflective surface of the retroreflective member is set so that the ratio of the blur amount l of the spatial floating image and the pixel size L of the image display device is 40% or less.
The light source device includes a point-shaped or planar light source and a light source.
An optical means for reducing the emission angle of light from the light source,
A light guide body having a reflecting surface that reflects light from the light source and propagates to the image display device.
It is provided with a retardation plate and a reflecting surface which are arranged in order from the light guide body so as to face the other surface of the light guide body.
The reflective surface of the light guide is arranged so as to reflect light from the light source and propagate to the image display device arranged facing the light guide, and is arranged with the reflective surface of the light guide. A reflective polarizing plate is arranged between the image display device and the image display device.
Light in a specific polarization direction reflected by the reflective polarizing plate is reflected by a reflecting surface arranged close to the other surface of the light guide, and is arranged between the light guide and the reflecting surface. Polarization conversion is performed by passing through the retardation plate twice, and light in a specific polarization direction is propagated to the liquid crystal display panel by passing through the reflective polarizing plate.
The liquid crystal display panel modulates the light intensity according to the video signal.
The light source device controls a part or all of the divergence angle of the light flux incident on the image display device from the light source by the shape and surface roughness of the reflecting surface provided on the light source device.
A spatial floating image display device that forms the spatial floating image in the air by reflecting an image luminous flux having a narrow divergence angle from the liquid crystal display panel on a retroreflective member. In the space floating image display device according to claim 22,
In the light source device, a part or all of the light emission divergence angle of the light beam is set to be within ± 30 degrees of the light ray divergence angle of the liquid crystal display panel constituting the image display device. A spatial floating image display device that is controlled by shape and surface roughness. In the space floating image display device according to claim 22,
In the light source device, a part or all of the light emission divergence angle of the light beam is provided on the light source device so that the light emission divergence angle of the liquid crystal display panel constituting the image display device is within ± 10 degrees. A spatial floating image display device that is controlled by the shape and surface roughness of the surface. In the space floating image display device according to claim 22,
The light source device is provided with a part or all of the light emission divergence angle of the light beam so that the light emission divergence angle of the liquid crystal display panel constituting the image display device is different from the horizontal divergence angle and the vertical divergence angle. Controlled by the shape and surface roughness of the reflective surface,
Space floating image display device. In the space floating image display device according to claim 22,
The light source device has contrast performance obtained by multiplying the contrast obtained by the characteristics of the polarizing plates provided on the light incident surface and the light emitting surface of the liquid crystal display panel by the inverse of the cross transmittance of the reflective polarizing plate. , Space floating image display device. In the space floating image display device according to claim 22,
Equipped with two reflective polarizing plates
The video light from the video display device is once reflected by the reflective polarizing plate and arranged so as to be incident on the retroreflective member, and a retardation plate is provided on the video light incident surface of the retroreflective member to provide the phase difference. A spatial floating image display device that converts the polarization of the image light into the other polarization by passing the image light twice through the plate and allows the image light to pass through the reflective polarizing plate. In the space floating image display device according to claim 27,
The light source device is a contrast obtained by multiplying the contrast obtained by the characteristics of the polarizing plates provided on the light incident surface and the light emitting surface of the liquid crystal display panel by the inverse of the cross transmittance of the two reflective polarizing plates. Spatial floating image display device with performance. The space floating image display device according to any one of claims 23 to 28.
The light source device is a space floating image display device including a plurality of the light sources for one image display element. The space floating image display device according to any one of claims 23 to 29.
The light source device is a spatial floating image display device including a plurality of surface emitting light sources having different light emission directions for one image display element. A light source device used for the space floating image display device according to any one of claims 28 to 30, wherein the divergence angle is within ± 30 degrees. The light source device according to claim 31, wherein the divergence angle is within ± 10 degrees. The light source device according to claim 32, wherein the horizontal diffusion angle and the vertical diffusion angle are different. A space floating image display device that forms a space floating image.
A liquid crystal display panel and a light source device that supplies light in a specific polarization direction to the liquid crystal display panel are provided.
The light source device includes a point-shaped or planar light source and a light source.
An optical means for reducing the emission angle of light from the light source,
A polarization conversion means for aligning the light from the light source with the polarization in a specific direction,
A light guide body having a reflective surface propagating to the liquid crystal display panel is provided.
The light guide is arranged so as to face the liquid crystal display panel.
A reflective surface is provided inside or on the surface of the light guide body to reflect the light from the light source toward the liquid crystal display panel, and the light is propagated to the liquid crystal display panel.
The liquid crystal display panel modulates the light intensity according to the video signal, and a part or all of the divergence angle of the light flux incident on the liquid crystal display panel from the light source is the shape and surface roughness of the reflecting surface provided on the light guide body. In a space floating image display system characterized by a light source device controlled by a light source and a spatial floating image display system characterized in that an image luminous flux having a narrow divergence angle from a liquid crystal display panel is reflected by a retroreflective member to form a floating image in the air.
A spatial floating image display device in which the shape of the retroreflective member is formed of a concave surface or a convex surface having a radius of curvature of 200 mm or more with respect to the image display device. The space floating image display device for forming the space floating image according to claim 24.
The shape of the retroreflective member is a concave or convex shape with respect to the image display device, and the radius of curvature thereof is 200 mm or less. A space floating image display device that forms a space floating image.
A liquid crystal display panel, a light source device that supplies light in a specific polarization direction to the liquid crystal display panel, a transmissive plate having a polarization separating member on the surface, an optical system including a retroreflective member, and the constituent members are housed. The housing is provided with an outer frame that holds the transparent plate and connects to the housing.
The image light of a specific polarization from the liquid crystal display panel is reflected by the polarization separating member, and the image light retroreflected by the retardation plate provided on the retroreflecting member is polarized and converted to pass through the polarization separating member and the transmissive plate. Let it form a floating image in space,
The optical system is arranged in the housing so that when a viewer of the floating image of space views the floating image of space, a part or all of the floating image of space hangs on a part or all of the outer frame. Space floating image display device.

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