JP2022029901A - Space floating video information display system and light source device used for the same - Google Patents

Abstract

To suitably display a space floating video.SOLUTION: A space floating video information display system comprises, as a video display device, a liquid crystal panel and a light source device supplying light having a specific polarization direction to the liquid crystal panel. The light source device comprises a point-like or a planar light source, optical means for reducing the divergence angle of light from the light source, polarized light conversion means for converting light from the light source to polarized light in a specific direction, and a light conductor having a reflection plane for propagating the light to the video display device. The light conductor is arranged facing the video display device and equipped, in the inside or on the surface, with a reflection plane for reflecting light from the light source toward the video display device, thus propagating light to the video display device. The liquid crystal panel modulates light intensity in accordance with video signals. The light source device controls the whole or part of divergence angle of a beam entering the video display device from the light source depending on the shape and surface roughness of the reflection plane provided in the light source device. A video beam having a narrow divergence angle from the liquid crystal panel is reflected by a recursive reflection member to form a space floating video in the air.SELECTED DRAWING: Figure 2

Description

The present invention relates to a spatial floating image information display system and a light source device used therein.

As a spatial floating information display system, a video display device that directly displays an image to the outside and a display method that displays the image as a spatial screen are already known. Further, for example, Patent Document 1 discloses a detection system that reduces erroneous detection of an operation on the operation surface of the displayed spatial image.

Japanese Unexamined Patent Publication No. 2019-128722

However, as a method for reducing false positives for the above-mentioned conventional spatial floating image information display system and operation of spatial images, consideration is given to design optimization technology including a light source of an image display device that is an image source of spatial floating images. It has not been.

Therefore, the present invention is a technique capable of displaying a suitable image having high visibility (appearance resolution and contrast) in a spatial floating information display system and reducing erroneous detection of an operation of the displayed spatial image. The purpose is to provide.

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. For example, the spatial floating image information display system supplies a liquid crystal panel and light in a specific polarization direction to the liquid crystal panel as an image display device. It is equipped with a light source device. 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 reflection propagating to the image display device. It is provided with a light source having a surface. The light guide is arranged so as to face the image display device, and a reflective surface for reflecting the light from the light source toward the image display device is provided inside or on the surface of the light guide to propagate the light to the image display device. do. The liquid crystal 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 beam incident on the image display device from the light source by the shape and surface roughness of the reflecting surface provided in the light source device. An image luminous flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member to form a space floating image in the air.

According to the present invention, it is possible to suitably display spatial floating image information, and to realize a spatial floating information display system having a sensing function with few false positives. 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 information 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 information display system which concerns on one Embodiment of this invention. It is a figure which shows the other example of the main part composition of the space floating image information display system which concerns on one Embodiment of this invention. It is a figure which shows the other example of the main part composition of the space floating image information display system which concerns on one Embodiment of this invention. It is explanatory drawing for demonstrating the function of the sensing apparatus used in the space floating image information display system. It is explanatory drawing of the principle of 3D image display used in a space floating image information display system. It is explanatory drawing of the measurement system which evaluated the characteristic of a reflective polarizing plate. It is a characteristic diagram which shows the transmittance characteristic with respect to the ray incident angle of a reflective polarizing plate transmission axis. It is a characteristic diagram which shows the transmittance characteristic with respect to the ray incident angle of a reflective polarizing plate reflection axis. It is a characteristic diagram which shows the transmittance characteristic with respect to the ray incident angle of a reflective polarizing plate transmission axis. It is a characteristic diagram which shows the transmittance characteristic with respect to the ray incident angle of a reflective polarizing plate reflection axis. 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 information 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 information 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 light source diffusion characteristic of a video display 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 device which constitutes the space floating image information display system. It is explanatory drawing for demonstrating the generation principle of the ghost image generated in the space floating image information display system by the prior art. It is sectional drawing which shows the structure of the image display apparatus which constitutes the space floating image information display system 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 can be made by those skilled in the art 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 embodiment, for example, an image generated by an image light from a large-area image emitting source is transmitted to the inside or outside of a store (space) through a transparent member that partitions a space such as a show window glass. It relates to an information display system that can be displayed as a floating image in space. It also relates to a large-scale digital signage system configured by using a plurality of such information 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 an acute 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 spatial floating image, which has been a problem in the conventional retroreflection method, and it is possible to obtain a clear spatial floating image. Further, the device including the light source of the present embodiment can provide a new and highly usable spatial floating image information display system capable of significantly reducing power consumption. Further, for example, a floating image information 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. can do.

On the other hand, in the conventional spatial floating image information display system, an organic EL panel or a liquid crystal panel is combined with the retroreflective member 151 as a high-resolution color display image source 150. Since the image light is diffused at a wide angle in the spatial floating image display device according to the prior art, in addition to the reflected light normally reflected by the retroreflective member 151, the image light incident on the retroreflective member 2a at an angle as shown in FIG. 24. Therefore, ghost images 301 and 302 are generated, which impairs the image quality of the spatial floating image. Further, as shown in FIG. 23, a plurality of first ghost images 301, second ghost images 302, and the like are generated in addition to the normal space floating image 300. For this reason, other than the observer, the floating image in the same space, which is a ghost image, is monitored, which poses a big problem in terms of security.

<Spatial floating video information display system 1>
FIG. 1 is a diagram showing an example of a usage pattern of a spatial floating image information display system according to an embodiment of the present invention. FIG. 1A is a diagram showing an overall configuration of a spatial floating image information display system according to this embodiment. For example, in a store or the like, the space is partitioned by a show window (also referred to as "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) by passing through the transparent member. Specifically, light having a narrow 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 3 (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 that displays the original image of the aerial image, a video control unit that converts the input video according to the resolution of the panel, and a video signal receiving unit that receives the video signal. There is. The video signal receiving unit supports wired input signals such as HDMI (High-Definition Multimedia Interface) input and wireless input signals such as Wi-Fi (Wireless Friend), and serves as a video receiving / displaying device. It also functions independently and can display video information from tablets, smartphones, etc. 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 a spatial floating image information display system according to an embodiment of the present invention. The configuration of the spatial floating image information display system will be described more specifically with reference to FIG. As shown in FIG. 2A, an image display device 1 for diverging 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 diffusion characteristic with a narrow angle.

The image light of the specific polarization from the image display device 1 is 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 a sheet. It is formed in a shape 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 a specific polarization to the other polarization by being passed through the λ / 4 plate 21 twice, when it is incident on the retroreflective member 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 airborne image 3 is a set of light rays that converge from the retroreflective member 2 to the optical image of the airborne image 3, and these rays travel straight even after passing through the optical image of the airborne image 3. .. Therefore, the airborne 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 the arrow A, the airborne image 3 is visually recognized as a bright image. However, when another person visually recognizes from the direction of the arrow B, the airborne image 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 image light whose polarization axes are not aligned is reflected by the above-mentioned polarization separation member 101 and returns to the image 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 the 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, FIG. 2B shows the surface shape of the retroreflective member manufactured by Nippon Carbite Industries Co., Ltd., which was used in this study as a typical retroreflective member 2. The light rays incident on the inside of the 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, and the real image is based on the image displayed on the image display device 1. Display a floating image of space. The resolution of this spatial floating image largely depends on the outer diameter D and the pitch P of the retroreflective portion 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 pixel) liquid crystal display panel is used, even if one pixel (1 triplet) is about 80 μm, for example, the diameter D of the retroreflective part may be 240 μm and the pitch may be 300 μm. For example, one pixel of the spatial floating image is equivalent to 300 μm. Therefore, the effective resolution of the spatial floating image is reduced to about 1/3. Therefore, in order to make the resolution of the spatial floating image equal to the resolution of the image display device 1, it is desired that the diameter and pitch of the retroreflective portion 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 and the liquid crystal display panel, it is advisable to design by excluding each pitch ratio from an integral multiple of one pixel. Further, the shape may be arranged so that neither side of the retroreflective portion overlaps with any one side of one pixel of the liquid crystal display panel.

On the other hand, in order to manufacture the retroreflective member at a low price, it is preferable to mold it by using the roll press method. Specifically, it is a method of aligning the recursive parts 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 make the space between the rolls. By passing the film, a required shape is formed and cured by irradiating with ultraviolet rays to obtain a retroreflecting member 2 having a desired shape.

<Spatial floating video information display system 2>
FIG. 3 is a diagram showing another example of the configuration of the main part of the spatial floating image information display system according to the embodiment of the present invention. FIG. 3A is a diagram showing another embodiment of the space floating image information display system. The image display device 1 includes a liquid crystal display panel 11 as an image display element 11 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 unit 2. The difference from the example shown in FIG. 2 is that the reflective sheet is provided along the convex shape. Therefore, the image light from the liquid crystal display panel 11 is diffused according to the shape of the concave surface and is incident on the recursive member 2. As a result, it is possible to obtain a spatial floating image 3 which is a real image expanded and enlarged from the screen display surface (display size is L1 in the figure) of the liquid crystal display panel 11. Further, the image luminous flux reflected by the retroreflective member 2 is polarized and converted, then transmitted through the convex reflective sheet, and then further diffused by the action of the concave surface provided on the other surface of the convex surface and transmitted through the transparent member 100. It is the spatial floating image L2 enlarged in the diagonal direction of FIG. 3 (A). At this time, the magnification M of the spatial floating image is M = L2 / L1. As described above, an optical member having a lens action is provided between the image display element 11 and the retroreflective member 2, or between the retroreflective member 2 and the spatially floating image, and in some cases, this optical member is recursed with the image display device. By eccentricity or tilting from the optical axis connecting the reflective members, the size and image formation position of the spatially floating image obtained in the image information system can be arbitrarily set with respect to the above-mentioned optical axis. As described above, if the size and image formation position of the spatial floating image are changed by the optical member, the spatial image is distorted as it is, but by displaying the corrected image on the image display device, the entire image information system is distorted. You can get an image without optics.

A λ / 4 plate 21 is provided on the light incident surface of the retrospective member 2, and the incident video light is reflected by the retroreflective member and then transmitted through the λ / 4 plate 21 again to convert the polarization of the video light into a convex surface. It passes through the polarization separating member 101 of. As a result, it is possible to form a spatial floating image having a size different from the size displayed on the liquid crystal display panel at a position transmitted through the transparent member 100.

<Spatial floating video information display system 3>
FIG. 3B is a diagram showing another example of the space floating image information display system. Similar to FIG. 3A, the image display element 11 constituting the image display device 1 includes a liquid crystal display panel 11 and a light source device 13 for generating light having a specific polarization having a narrow angle diffusion characteristic, and has a screen size. It can be configured from a small size of about 5 inches to a large liquid crystal display panel 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 unit 2. The difference from the example of FIG. 2 is that the obtained spatial floating image is magnified as a virtual image X by the concave mirror 5. The configurations of the image display device 1 and the retroreflective member 2 are the same as those of the embodiments shown in FIGS. 2 and 3 (A), and the description thereof will be omitted. In addition, in the configuration of FIG. 3B, the polarization separating member 101 may be further formed into a convex shape.

Here, as described with reference to FIG. 2, since the airborne image 3 is formed by light rays having high directivity, the airborne image 3 is visually recognized as a bright image when viewed from the direction of the arrow A, but the arrow. When visually recognizing from the direction of B, the airborne image 3 is not visually recognized at all as an image. Therefore, in the configuration of FIG. 3B, the airborne image 3 is located behind the virtual image X when the user visually recognizes it from the direction of the arrow B, but the user does not see the airborne image 3 at all. Only the virtual image X is preferably visually recognized without being visually recognized. Therefore, if this characteristic is utilized and the air floating image 3 is configured to be located behind the virtual image X as shown in FIG. 3 (B), the air floating from the viewing range of the user X when the virtual image X is visually recognized. It is preferable because the entire system can be miniaturized rather than being configured to exclude the image 3.

<Spatial floating video information display system 4>
FIG. 4 is a diagram showing another example of the configuration of the main part of the spatial floating image information display system according to the embodiment of the present invention. Similar to FIG. 3A, the image display element 11 constituting the image display device 1 includes a liquid crystal display panel 11 and a light source device 13 for generating light having a specific polarization having a narrow angle diffusion characteristic, for example. It is composed of a small liquid crystal display panel having a screen size of about 5 inches to a large liquid crystal display panel exceeding 80 inches, and a polarization separating member 101 such as a reflective polarizing plate is provided on the surface of the folded mirror 22 to provide a liquid crystal display panel 11. The image light from the above is reflected toward the retroreflective unit 2. The image light of the specific polarization from the image display device 1 is reflected by a film (adhesive to the sheet 101 in the figure) that selectively reflects the image light of the specific polarization provided on the transparent member 100, and is a retroreflective member. It is incident on 2.

A λ / 4 plate 21 is provided on the light incident surface of the retroreflective member, and the polarization separation member 101 is transmitted by converting the specific polarization to the other polarization by passing the video light twice to convert the polarization. , The spatial 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. 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 spatial floating image. .. 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 12 on the surface of the transparent member 105. The polarization separating member 101 is formed of a reflective polarizing plate or a metal multilayer film that reflects a specific polarization.

Next, the sensor 44 having a TOF (Time of Fly) function is illustrated so as to sense the relationship between the distance and the position of the object and the sensor 44 with respect to the spatial floating image obtained by the above-mentioned spatial floating image information system. By arranging them in a plurality of layers as shown in 5, it is possible to detect the coordinates in the depth direction, the moving direction of the object, and the moving speed in addition to the coordinates in the plane direction of the object. In order to read the two-dimensional distance and position, a plurality of combinations of the ultraviolet light emitting part and the light receiving part are arranged linearly, the light from the light emitting point is irradiated to the object, and the reflected light is received by the light receiving part. The distance to the object becomes clear by the product of the difference between the time when light is emitted and the time when light is received and the speed of light. Further, the coordinates on the plane are a plurality of light emitting parts and light receiving parts, and can be read from the coordinates at the part where the difference between the light emitting time and the light receiving time is the smallest. From the above, it is possible to obtain three-dimensional coordinate information by combining the coordinates of an object in a plane (two-dimensional) and a plurality of the above-mentioned sensors.

Further, a method of obtaining a three-dimensional space floating image as the above-mentioned space floating image information system will be described with reference to FIG. FIG. 6 is an explanatory diagram of the principle of three-dimensional image display used in the spatial floating image information display system. A horizontal lenticular lens is arranged so as to match the pixels of the image display screen of the liquid crystal display panel 11 of the image display device 1 shown in FIG. As a result, as shown in FIG. 6, in order to display the motion deviation from the three directions P1, P2, and P3 in the horizontal direction of the screen, the image from the three directions is regarded as one block for every three pixels, and one pixel. Image information from three directions is displayed for each, and the emission direction of light is controlled by the action of the corresponding lenticular lens (indicated by a vertical line in FIG. 6) to separate and emit light in three directions. As a result, a three-dimensional image with three parallax can be displayed.

<Reflective polarizing plate>
In the spatial floating image information device of this embodiment, the polarization splitting member 101 is used to improve the contrast performance that determines the image quality of the image as compared with a general half mirror. The characteristics of the reflective polarizing plate will be described as an example of the polarization separating member 101 of this embodiment. FIG. 7 is an explanatory diagram of a measurement system for evaluating the characteristics of the reflective polarizing plate. The transmission characteristics and the reflection characteristics with respect to the incident angle of the light beam from the direction perpendicular to the polarization axis of the reflective polarizing plate of FIG. 7 are shown as V-AOI in FIGS. 8 and 9, respectively. Similarly, the transmission characteristics and the reflection characteristics with respect to the incident angle of light rays from the horizontal direction with respect to the polarization axis of the reflective polarizing plate are shown as H-AOI in FIGS. 10 and 11, respectively.

As shown in FIGS. 8 and 9, the reflective polarizing plate having a grid structure 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 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 this embodiment will be described below in which a light source capable of emitting the image light emitted from the liquid crystal display panel at a narrower angle is used as the backlight of the liquid crystal display panel. This makes it possible to provide a high-contrast spatial floating image.

<Video display device>
Next, the video display device 1 of this embodiment will be described with reference to the drawings. The video display device of this embodiment includes a light source device 13 constituting the light source together with the video display element 11 (liquid crystal display panel), and in FIG. 12, the light source device 13 is shown as a developed perspective view together with the liquid crystal display panel. There is.

As shown by the arrow 30 in FIG. 12, the liquid crystal display panel (image display element 11) has a diffusion characteristic with a narrow angle due to the light from the light source device 13 which is a backlight device, that is, directional (straightness). The retroreflective member 2 reflects the video light that has been modulated according to the input video signal by obtaining an illumination light source that is strong and has characteristics similar to laser light with the polarizing planes aligned in one direction. It passes through the glass 105 to form a spatial floating image that is a real image. (See FIG. 1). Further, in FIG. 12, the liquid crystal display panel 11 constituting the image display device 1, the optical direction conversion panel 54 for controlling the directivity characteristic of the luminous flux emitted from the light source device 13, and the interstitial angle diffuser plate as necessary. 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. 12). .. 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 observer outside (space). A protective cover 50 (see FIGS. 13 and 14) may be provided on the surface of the above-mentioned optical direction conversion panel 54.

In this embodiment, in the video display device 1 including the light source device 13 and the liquid crystal display panel 11 in order to improve the utilization efficiency of the luminous flux 30 emitted from the light source device 13 and significantly reduce the power consumption. Light from the light source device 13 (see arrow 30 in FIG. 12) 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 (not shown). Therefore, the directivity can be controlled so as to form a floating image 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 show window 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 element 201 of the light source device 13.

<Example 1 of video display device>
FIG. 13 shows an example of a specific configuration of the video display device 1. In FIG. 13, a liquid crystal display panel 11 and an 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 on the case shown in FIG. 12, and is configured by accommodating the LED element 201 and the light guide body 203 inside the case, and is configured on the end surface of the light guide body 203. As shown in FIG. 12 and the like, has a shape in which the cross-sectional area gradually increases toward the light receiving portion in order to convert the divergent light from each LED element 201 into a substantially parallel luminous flux. However, a lens shape is provided that has the effect of gradually reducing the divergence angle by totally reflecting the light a plurality of times when propagating inside. A liquid crystal display panel 11 constituting the image display device 1 is attached to the upper surface thereof. Further, an LED (Light Emitting Diode) element 201, which is a semiconductor light source, and an LED substrate 202 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 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 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. An FPC (Flexible Printed Circuits: Flexible Wiring Board) (not shown) or the like is attached and configured. That is, the liquid crystal display panel 11 which is a liquid crystal 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 that is close to the surface-emitting laser video source driven by the video signal can be obtained. .. 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 an LED element.

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. 13 and FIG.

Since FIGS. 13 and 14 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 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 external shape of the light receiving portion of the light receiving body to which the LED element 201 is attached has a parabolic shape forming a conical outer peripheral surface, and the light emitted from the LED element in the peripheral direction may be totally reflected inside the parabolic shape. It is set within a possible angle range, 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. The divergent light is guided 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 the arrow, and the light source direction changing means 204 is used. The light is emitted toward the liquid crystal display panel 11 arranged substantially parallel to the light guide (direction perpendicular to the front from the drawing). By optimizing the distribution (density) of the light flux direction changing means according to the shape of the inside or the surface of the light guide body, 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 arranges the light flux propagating in the light guide body substantially parallel to the light guide body by providing, for example, a portion having a different refractive index inside the light guide body and the shape of the surface of the light guide body. It emits light toward the liquid crystal display panel 11 (in a direction perpendicular to the front from the drawing). At this time, 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, it is practical. There is no problem, and if it exceeds 30%, the characteristics will be even better.

Note that FIG. 13 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. 13, 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 206. 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.

Further, a film or sheet-shaped reflective polarizing plate 49 is provided on the light incident surface (lower surface of the figure) of the liquid crystal display panel 11 corresponding to the light source device 13, and among the natural light beams 210 emitted from the LED element 201. The polarization (for example, P wave) 212 on one side is selectively reflected, reflected by the reflection sheet 205 provided on one surface (lower part of the figure) of the light guide 203, and directed toward the liquid crystal display panel 52 again. To. Therefore, a retardation plate (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. Converts the reflected light beam from P-polarized light to S-polarized light to improve the efficiency of using the light source light as the image light. The image luminous flux whose light intensity is modulated by the image signal on the liquid crystal display panel 11 (arrow 213 in FIG. 13) 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 floating image of space, which is a real image, inside or outside the store (space).

FIG. 14 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 the surface or inside formed of, for example, plastic, an LED element 201 as a light source, a reflection sheet 205, a retardation plate 206, and a wrenchular 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 of 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 light source 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. A retardation plate (λ / 4 plate) is provided between the light guide 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 reflection sheet 205 and reflected twice. The light beam is converted from S-polarized light to P-polarized light, and the utilization efficiency of the light source light as video 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. 14) 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, which is a real image, can be obtained inside or outside the (space).

In the light source device shown in FIGS. 13 and 14, in addition to the action of the polarizing plate provided on the light incident surface of the corresponding liquid crystal display panel 11, the reflective polarizing plate reflects the polarization component on one side, which is theoretically obtained. The contrast ratio obtained is the product of the inverse of the cross transmittance of the reflective polarizing plate and the inverse of the cross transmittance obtained by the two polarizing plates attached to the liquid crystal display panel. 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 2 of video display device>
FIG. 15 shows another example of a specific configuration of the video display device 1. The light source device 13 of FIG. 15 is similar to the light source device of FIG. 17 and the like. The light source device 13 is configured by accommodating an LED, a collimator, a synthetic diffusion block, a light guide body, and the like in a case such as plastic, and a liquid crystal display panel 11 is attached to the upper surface thereof. Further, an LED (Light Emitting Diode) elements 14a and 14b, which are semiconductor light sources, and an LED board 102 on which the control circuit thereof is mounted are mounted on one side surface of the case of the light source device 13, and the outer surface of the LED board 102 is attached. A heat sink 103, which is a member for cooling the heat generated by the LED element and the control circuit, is attached to the LED element (see also FIGS. 17 and 18).

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. 7) and the like are attached and configured. That is, the liquid crystal display panel 11 which is a liquid crystal display element has the intensity of transmitted light based on the control signal from the control circuit (not shown here) constituting the electronic device together with the LED elements 14a and 14b which are solid light sources. Is generated by modulating the display image.

<Example 3 of video display device>
Subsequently, another example of a specific configuration of the image display device 1 will be described with reference to FIG. The light source device of the image display device 1 converts the divergent luminous flux of natural light (a mixture of P-polarization and S-polarization) from the LED into a substantially parallel luminous flux by the LED collimator 18, and the liquid crystal display panel by the reflective light guide 304. It reflects toward 11. The reflected light is incident on the wave plate and the reflective polarizing plate 49 arranged between the liquid crystal display panel 11 and the reflective light guide 304. A specific polarization (for example, S polarization) is reflected by the reflection type polarizing plate, the phase is converted by the wavelength plate, and the polarization returns to the reflection surface, passes through the retardation plate again, and passes through the reflection type polarizing plate (for example, P bias). Wave) is converted.

As a result, the natural light from the LED is aligned with a specific polarization (for example, P polarization), is incident on the liquid crystal display panel 11, is brightly 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, only one is shown in FIG. 16 because of the vertical cross section), and these are mounted in a predetermined position with respect to the LED collimator 18. .. The LED collimator 18 is made of a translucent resin such as acrylic or glass, respectively. The LED collimator 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 in the central portion 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 paraboloid surface forming the conical outer peripheral surface of the LED collimator 18 is set within an angle range at which light emitted from the LED in the peripheral direction can be totally reflected inside the paraboloid surface, or is a reflective surface. Is formed.

The above configuration is the same as that of the light source device of the video display device shown in FIGS. 17, 18 and the like. Further, the light converted into substantially parallel light by the LED collimator 18 shown in FIG. 16 is reflected by the reflective light guide 304, and the light of a specific polarization is transmitted by the action of the reflective polarizing plate 49 and reflected. The polarized light of the above passes through the light guide 304 again and is reflected by the reflector 271 provided on the other surface of the light guide that does not come into contact with the liquid crystal display panel 11. At this time, the polarizing is converted by passing twice through the retardation plate (λ / 4 plate) 270 arranged between the reflector 271 and the liquid crystal display panel 11, and the light guide 304 is transmitted again to the opposite surface. It passes through the provided 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 light utilization efficiency is doubled.

The light emitted from the liquid crystal display panel 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. 22 (a)) and the vertical direction of the screen (displayed on the Y-axis in FIG. 22 (b)). ing. On the other hand, as for the diffusion characteristic of the luminous flux emitted from the liquid crystal display panel of this embodiment, for example, as shown in Example 1 of FIG. 22, the viewing angle at which the brightness is 50% of the front view (angle 0 degree) is 13 degrees. By setting it to, 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. 22 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 image 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 setting the viewing angle as the narrowing 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 an information display system for the outdoors. It can be a video display device compatible with the above.

When using a large LCD panel, the light around the screen is directed inward so that the center of the screen faces the observer when the observer faces it, thereby improving the overall brightness of the screen. do. FIG. 20 shows the convergence angles of the long side and the short side of the panel when the distance L from the observer's panel and the panel size (screen ratio 16:10) are used as parameters. When monitoring the screen vertically, the convergence angle may be set according to the short side. For example, if the 22 "panel is used vertically and the monitoring distance is 0.8 m, the convergence angle is 10 degrees. The image light from the four corners can be effectively directed to the observer.

Similarly, when monitoring with 15 "vertical use of the panel, if the monitoring distance is 0.8 m and the convergence angle is 7 degrees, the image light from the screen 4 corner can be effectively directed to the observer. As mentioned above, depending on the size of the LCD panel and whether it is used vertically or horizontally, the image light around the screen is directed to the observer who is in the optimum position to monitor the center of the screen, so that the overall screen brightness is complete. Can be improved.

As a basic configuration, as shown in FIG. 16, 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 luminance is modulated according to the video signal, so that the light flux is displayed on the screen of the liquid crystal display panel 11. The spatially floating image obtained by reflecting the generated image information by the retroreflective member is displayed outdoors or indoors via the wind glass 105.

<Example 1 of light source device>
Subsequently, the configuration of the optical system such as the light source device housed in the case will be described in detail together with FIG. 17 with reference to FIGS. 18 (a) and 18 (b).

17 and 18 show LEDs 14a and 14b constituting the light source, which are attached at predetermined positions with respect to the LED collimator 15. Each of the LED collimators 15 is made of a translucent resin such as acrylic. As shown in FIG. 18B, 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 parabolic surface 156 forming the conical outer peripheral surface of the LED collimator 15 is set within an angle range at which the light emitted from the LEDs 14a and 14b in the peripheral direction can be totally reflected inside the paraboloid surface 156. , A reflective surface is formed.

Further, the LEDs 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 LEDs 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 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 the light of the LED collimator 15. The two convex lens surfaces 157 and 154 forming the outer shape 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 of the LED collimator 15, and is similarly condensed into parallel light. In other words, according to the LED collimator 15 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 LEDs 14a or 14b can be taken out as parallel light. Therefore, it is possible to improve the utilization efficiency of the generated light.

A polarization conversion element 21 is provided on the light emitting side of the LED collimator 15. As is clear from FIG. 18, 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 213 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. 18A is provided on the emission surface of the polarization conversion element 21. That is, the light emitted from the LED 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 exit side, and then reaches the light guide body 17.

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. 18 (b)), and as is clear from FIG. 17, 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 diffusion. A light guide body light emitting portion (plane) 173 facing the liquid crystal display panel 11 which is a liquid crystal display element is provided via the plate 18b.

As shown in FIG. 17, which is a partially enlarged view of the light guide body light reflecting portion (plane) 172 of the light guide body 17, a large number of reflecting surfaces 172a and connecting surfaces 172b are alternately serrated. It is formed. 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 the figure, 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 in the figure.

According to the information 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 information 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, the light emitting portion (plane) 173 of the light guide body is provided with a narrowing angle diffuser plate to be incident on the optical direction conversion panel 54 that controls the directivity characteristics as a substantially parallel diffused light beam, and is incident from an oblique direction. It is incident on the liquid crystal display panel 11. 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 2 of light source device>
FIG. 19 shows another example of the configuration of the optical system such as the light source device 13. Similar to the example shown in FIG. 18, a plurality of (two in this example) LEDs 14a and 14b constituting the light source are shown, and these 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. And, like the example shown in FIG. 18, 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 in the center thereof. , Convex lens surface) 157 has a concave portion 153. 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 parabolic surface 156 forming the conical outer peripheral surface of the LED collimator 15 is set or reflected within an angle range within which the light emitted from the LED 14a in the peripheral direction can be totally reflected. A surface is formed.

Further, the LEDs 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 LEDs 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 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 the light of the LED collimator 15. The two convex lens surfaces 157 and 154 forming the outer shape 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 of the LED collimator 15, and is similarly condensed into parallel light. In other words, according to the LED collimator 15 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 LEDs 14a or 14b can be taken out as parallel light. Therefore, it is 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 diffuser 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. 19A), and as is clear from FIG. 19A. In addition, an incident portion (plane) 171 of the light guide body light 170 facing the emission surface of the diffusion block 16 via the first diffuser plate 18a, and a light guide body light reflection portion (plane) 172 forming a slope. It includes a light guide body light emitting portion (plane) 173 facing the liquid crystal display panel 11 which is a liquid crystal display element via the reflective polarizing plate 200.

If, for example, 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 as a light source, and FIG. 19 (b) shows. It passes through the λ / 4 plate 202 provided in the light guide body light reflecting unit 172 shown in the above, is reflected by the reflecting surface 201, and is converted into S polarization by passing through the λ / 4 plate 202 again, and is converted into S-polarized light. All the light rays incident on the are unified to S polarization.

Similarly, if a reflective polarizing plate 200 having a characteristic of reflecting S-polarized light (transmitting P-polarized light) is selected, the S-polarized light of the natural light emitted from the LED as the light source is reflected, and FIG. 19 (b) shows. It passes through the λ / 4 plate 202 provided in the light guide body light reflecting unit 172 shown in the above, is reflected by the reflecting surface 201, and is converted into P-polarized light by passing through the λ / 4 plate 202 again to be converted into P-polarized light. All the light rays incident on the are unified to P polarization. Polarization conversion can be realized even with the above-mentioned configuration.

<Example 3 of light source device>
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. 16, the divergent luminous flux of natural light (a mixture of P-polarized light and S-polarized light) from the LED 102 is converted into a substantially parallel luminous flux by the collimator lens 18, and the liquid crystal display panel by the reflective light guide 304. It reflects toward 11. The reflected light is incident on the reflective polarizing plate 206 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 206, 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 plane of polarization converted to polarization, 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. 16 because of the vertical cross section), and these are attached to the LED collimator 18 at a predetermined position. .. The LED collimator 18 is made of a translucent resin such as acrylic or glass, respectively. The LED collimator 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 in the central portion 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 paraboloid surface forming the conical outer peripheral surface of the LED collimator 18 is set within an angle range at which the light emitted from the LED 18 in the peripheral direction can be totally reflected inside the paraboloid surface, or is 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 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 18, the light radiated from the central portion thereof is collected and parallel by the two convex lens surfaces forming the outer shape of the LED collimator 18. It becomes 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 18, and is similarly condensed into parallel light. In other words, according to the LED 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 generated light.

<Example 4 of light source device>
Further, another example of the configuration of an optical system such as a light source device will be described with reference to FIG. 25. On the light emitting side of the LED collimator 18, two optical sheets 207 that convert the diffusion characteristics in the vertical direction and the horizontal direction (not shown in the front-rear direction of the figure) in the drawing are used, and two pieces of light from the LED collimator 18 are used. It is incident between the optical sheets 207 (diffuse sheets) of the above. When the optical sheet 207 is composed of one sheet, the vertical and horizontal diffusion characteristics are controlled by the fine shapes of the front surface and the back surface. Further, a plurality of diffusion sheets may be used to share the action. Depending on the front surface shape and back surface shape of the optical sheet 207, the diffusion angle of the light from the LED collimator 18 in the vertical direction of the screen is matched with the width of the vertical surface of the reflection surface of the diffusion sheet, and the horizontal direction is the light flux emitted from the liquid crystal display panel 11. It is preferable to optimally design the number of LEDs and the divergence angle from the optical element 102 as design parameters so that the surface density becomes uniform. That is, the diffusion characteristics are controlled by the surface shapes of a plurality of diffusion sheets instead of the light guide. In this embodiment, the polarization conversion is performed in the same manner as in Example 3 of the light source device described above. On the other hand, a polarization conversion element 21 may be provided between the LED collimator 18 and the diffusion film 207 to perform polarization conversion, and then the light source light may be incident on the diffusion sheet 207.

If the above-mentioned reflective polarizing plate 206 has a characteristic of reflecting S-polarization (P-polarization is transmitted), S-polarization is reflected among the natural light emitted from the LED as a light source, and is shown in FIG. 25. It passes through the retardation plate 270, is reflected by the reflecting surface 271, and is converted into P-polarized light by passing through the retardation plate 270 again to be incident on the liquid crystal display panel 11. It is necessary to select the optimum value for the thickness of the retardation plate according to the angle of incidence of the light beam on the retardation plate, and the optimum value exists in the range of λ / 16 to λ / 4.

<Lenticular lens>
In order to control the diffusion distribution of the image light from the liquid crystal display panel 11, a lenticular lens is provided between the light source device 13 and the liquid crystal display panel 11 or on the surface of the liquid crystal display panel 11 to optimize the lens shape. This makes it possible to control the emission characteristics in one direction. Further, by arranging the microlens arrays in a matrix, the emission characteristics of the image luminous flux from the image display device 1 can be controlled in the X-axis and Y-axis directions, and as a result, the image display device having the desired diffusion characteristics can be obtained. Obtainable.

The operation of the lenticular lens will be described. By optimizing the lens shape of the lenticular lens, it is possible to efficiently obtain a spatial floating image by being 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, as shown in FIG. 22 (b), the luminance characteristic in the vertical direction is steepered by such a lenticular lens as compared with the conventional case, and the directional characteristic in the vertical direction (positive / negative direction of the Y axis) is balanced. By increasing the brightness (relative brightness) of the light due to reflection and diffusion by changing, the diffusion angle is narrow (high straightness) and only a specific polarization component, like the image light from a surface-emitting laser image source. It is possible to suppress the ghost image generated by the retroreflective member when the conventional image display device is used, and efficiently control the spatial floating image by retroreflective to reach the observer's eyes.

Further, by the above-mentioned light source device, the X-axis direction and the Y-axis direction are relative to the emission light diffusion characteristic characteristics (denoted as conventional in the figure) from the general liquid crystal display panel shown in FIGS. 22 (a) and 22 (b). By setting both of them to have a directional characteristic with a significantly narrow angle, it is possible to realize a video display device that emits light of a specific polarization that emits an image luminous flux that is almost parallel to a specific direction.

FIG. 21 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. 21 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 and the field of view of the image light aligned with the narrow angle by the light source device 13 The angle can be controlled and the degree of freedom in installing the retroreflective sheet 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 formed at a desired position by reflecting or transmitting the wind glass 105 can be greatly improved. As a result, it is possible to efficiently reach the eyes of the observer 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 observer 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 an information 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.

1 ... Image display device, 2 ... Retroreflective member, 3 ... Spatial image (spatial floating image), 105 ... Wind glass, 100 ... Transmissive plate, 101 ... Polarizing separation member, 12 ... Absorption type polarizing plate, 13 ... Light source device , 54 ... Optical direction conversion panel, 151 ... Retroreflective member, 102, 202 ... LED substrate, 203 ... Light source, 205, 271 ... Reflective sheet, 206, 270 ... Phase difference plate, 300 ... Spatial floating image, 301 ... Ghost image of floating image in space, 302 ... Ghost image of floating image in space

Claims (26)

It is a space floating image information display system that forms a space floating image.
The image display device includes a liquid crystal panel and a light source device that supplies light in a specific polarization direction to the liquid crystal panel.
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 video display device, and a reflective surface for reflecting light from the light source toward the video display device is provided inside or on the surface of the light guide, and the video is provided. Propagate light to the display device
The liquid crystal 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.
An image luminous flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member to form the space floating image in the air.
Spatial floating video information display system. In the space floating image information display system according to claim 1,
In the light source device, a part or all of the light emission divergence angle is set to the shape of the reflection surface of the light source device so that the light emission divergence angle of the liquid crystal panel constituting the image display device is within ± 30 degrees. Controlled by surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 1,
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 panel constituting the image display device is within ± 10 degrees, and the shape and surface of the reflection surface of the light source device. Controlled by roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 1,
In the light source device, a part or all of the light emission divergence angle of the light beam is set on the reflection surface of the light source device so that the light emission divergence angle of the liquid crystal panel constituting the image display device is different from the horizontal divergence angle and the vertical divergence angle. Controlled by shape and surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 1,
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 panel by the inverse of the efficiency of the polarization conversion in the polarization conversion means.
Spatial floating video information display system. In the space floating image information display system according to claim 1,
The image light from the image display device 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 video light incident surface of the retroreflective member, and the video light passes through the retardation plate twice to convert the polarization of the video light into the other polarization. Pass the polarizing plate,
Spatial floating video information display system. In the space floating image information display system according to claim 6,
In the light source device, 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 panel is the inverse of the efficiency of the polarization conversion in the polarization conversion means and the cross transmission rate of the reflective polarizing plate. It has a contrast performance that is multiplied by the inverse of each.
Spatial floating video information display system. It is a space floating image information display system that forms a space floating image.
The image display device includes a liquid crystal panel and a light source device that supplies light in a specific polarization direction to the liquid crystal panel.
The light source device is a light guide having a point-shaped or planar light source, an optical means for reducing the emission angle of light from the light source, and a reflecting surface that reflects the light from the light source and propagates to the image display device. With a body,
The light guide is arranged so as to face the image display device, and a reflective surface for reflecting light from the light source toward the image display device is provided inside or on the surface of the light guide to reflect the light. Light in a specific polarization direction reflected by the type polarizing plate is transmitted through a surface connecting the adjacent reflection surfaces of the light guide body, and is provided on a surface opposite to the surface of the light guide body in contact with the liquid crystal panel. It is reflected by a reflecting plate, polarized by passing through a retardation plate arranged on the upper surface of the reflecting plate twice, converted into a polarization that passes through the reflective polarizing plate, and passed through the light guide. Propagate light to the video display device with
The liquid crystal 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.
An image luminous flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member to form the space floating image in the air.
Spatial floating video information display system. It is a space floating image information display system that forms a space floating image.
The image display device includes a liquid crystal panel and a light source device that supplies light in a specific polarization direction to the liquid crystal panel.
The light source device has a point-shaped or planar light source, an optical means for reducing the emission angle of light from the light source, and a light guide having a reflecting surface that reflects light from the light source and propagates to the image display device. It comprises a body and a retardation plate and a reflective surface which are sequentially arranged from the light guide so as to face the other surface of the light guide.
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 panel by passing through the reflective polarizing plate.
The liquid crystal 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.
An image luminous flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member to form the space floating image in the air.
Spatial floating video information display system. In the space floating image information display system according to claim 8,
In the light source device, a part or all of the light emission divergence angle of the light beam is provided in the light source device so that the light emission divergence angle of the liquid crystal panel constituting the image display device is within ± 30 degrees. And controlled by surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 8,
In the light source device, a part or all of the light emission divergence angle of the light beam is set to be within ± 10 degrees of the light ray divergence angle of the liquid crystal panel constituting the image display device. Controlled by shape and surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 8,
In the light source device, a part or all of the divergence angle of the luminous flux is provided in the light source device so that the light emission divergence angle of the liquid crystal panel constituting the image display device is different from the horizontal divergence angle and the vertical divergence angle. Controlled by surface shape and surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 8,
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 panel by the inverse of the cross transmittance of the reflective polarizing plate.
Spatial floating video information display system. In the space floating image information display system according to claim 8,
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. When the image light passes through the plate twice, the polarization of the image light is converted into the other polarization, so that the reflection type polarizing plate is passed.
Spatial floating video information display system. In the space floating image information display system included in the space floating image information display display system according to claim 14,
The light source device has a 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 panel by the inverse of the cross transmittance of the two reflective polarizing plates. Is equipped with
Spatial floating video information display system. It is a space floating image information display system that forms a space floating image.
An image control input unit having a TOF (Time of Fly) function so as to sense the distance between the object and the sensor and the position of the object with respect to the displayed spatial floating image, an image display device, and an image display device. Equipped with
The image display device includes a liquid crystal panel and a light source device that supplies light in a specific polarization direction to the liquid crystal panel.
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 video display device, and a reflective surface for reflecting light from the light source toward the video display device is provided inside or on the surface of the light guide, and the video is provided. Propagate light to the display device
The liquid crystal 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 reflection surface provided on the light source device.
The spatial floating image is formed in the air in which the image light flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member.
Spatial floating video information display system. In the space floating image information display system according to any one of claims 1 to 16.
The light source device includes a plurality of the light sources for one image display element.
Spatial floating video information display system. In the space floating image information display system according to any one of claims 1 to 17.
The light source device includes a plurality of surface-emitting light sources having different light emission directions for one image display element.
Spatial floating video information display system. A light source device used in the spatial floating image information display system according to any one of claims 16 to 18.
The divergence angle is within ± 30 degrees.
Light source device. In the light source device according to claim 19,
The divergence angle is within ± 10 degrees.
Light source device. In the light source device according to claim 19,
The horizontal diffusion angle and the vertical diffusion angle are different,
Light source device. It is a space floating image information display system that forms a space floating image.
The image display device includes a liquid crystal panel and a light source device that supplies light in a specific polarization direction to the liquid crystal panel.
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 video display device, and a reflective surface for reflecting light from the light source toward the video display device is provided inside or on the surface of the light guide, and the video is provided. Propagate light to the display device
The liquid crystal 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.
An image luminous flux having a narrow divergence angle from the liquid crystal panel is reflected by the recurrence reflection member to form the space floating image in the air.
An optical member having a lens action is provided between the image display device and the retroreflective member, and / or between the retroreflective member and the space floating image.
Spatial floating video information display system. In the space floating image information display system according to claim 22,
The size of the spatial floating image obtained by eccentricity or tilting the optical member from the optical axis connecting the image display device and the retroreflective member and the image formation position of the spatial floating image are relative to the optical axis. Arbitrarily set,
Spatial floating video information display system. In the space floating image information display system according to claim 22,
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 panel constituting the image display device is within ± 30 degrees, and the shape and surface of the reflection surface of the light source device. Controlled by roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 22,
In the light source device, a part or all of the light emission divergence angle is set to the shape of the reflection surface of the light source device so that the light emission divergence angle of the liquid crystal panel constituting the image display device is within ± 10 degrees. Controlled by surface roughness,
Spatial floating video information display system. In the space floating image information display system according to claim 22,
In the light source device, a part or all of the divergence angle of the light beam is used as the reflection surface of the light source device so that the light emission angle of the liquid crystal 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
Spatial floating video information display system.

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