WO2020017140A1 - Video display device and video display system - Google Patents

Abstract

Through the present invention, a light-guiding-plate-type video display device in which an entire image is visible to a user is reduced in size. This video display device is characterized by being provided with a video projection part for causing light to scan and generating video light having a predetermined angle of view, a light-guiding plate for causing the video light incident from a light input part to propagate inside the light-guide plate and outputting the video light from a light output part, and a video light reproduction part for reproducing a light beam of the video light, the video light reproduction part reproducing two or more video lights having substantially the same angle of view as the incident video light.

Description

Video display device and video display system

The present invention relates to a video display device and a video display system. The present invention claims the priority of Japanese Patent Application No. 2018-136391, filed on July 20, 2018, and, for designated countries where weaving by reference to documents is permitted, the contents described in that application are Incorporated by reference into this application.

Conventionally, an image display device of a system using a light guide plate represented by a head-mounted display is known.

For example, Japanese Patent Application Laid-Open Publication No. HEI 11-163572 discloses a technique in which a laser beam having directivity is emitted from the tip of a fiber and the tip of the fiber is related to an image display apparatus using the above-described method using a light guide plate (hereinafter, referred to as a light guide plate method). There is disclosed a technology related to a fiber-scanning image generation apparatus that generates an image by scanning an image. According to the fiber-scanning image generation apparatus, a projection lens for projecting an image is not required, so that the apparatus scale can be reduced.

Patent Document 2 discloses a technique related to a light guide plate that enlarges a pupil size, which is a light beam diameter of image light displayed on an image display device, and transmits image light to a pupil of a user's eye. According to the light guide plate, since the pupil size is enlarged, an eye box (an area where a user can visually recognize an image) can be enlarged.

International Publication No. WO 2017/163386 International Publication No. WO 2016/020463

組 み 合 わ せ By combining the light guide plate described in Patent Literature 2 with the fiber-scanning video generation device described in Patent Literature 1, the size of the light guide plate type image display device can be reduced. However, in such a configuration, the diameter of the exit pupil of the image light supplied to the light guide plate from the fiber scanning image generation device is substantially equal to the diameter of the directional laser light, and Is very small compared to the interval of the image light. For this reason, the plurality of image lights output from the light guide plate do not overlap each other, and the image light does not enter the pupil of the user's eye. This may cause the user to visually recognize at least a part of the image. It can happen.

The present invention has been made in view of such a situation, and an object of the present invention is to realize a light guide plate type image display device in which a user can visually recognize the entire image.

Although the present application includes a plurality of means for solving at least a part of the above-described problems, examples thereof are as follows. In order to solve the above problem, an image display device according to one embodiment of the present invention includes an image projection unit that scans light to generate image light having a predetermined angle of view, and internally transmits the image light incident from a light input unit. A light guide plate that propagates through the light output unit and outputs a light beam of the image light, and an image light duplication unit that duplicates the light beam of the image light, wherein the image light duplication unit has an angle of view substantially the same as the incident image light. It is characterized in that two or more of the video lights included are duplicated.

According to the present invention, it is possible to realize a light guide plate type image display device in which a user can visually recognize the entire image.

The problems, configurations, and effects other than those described above will be apparent from the following description of the embodiments.

1 is a block diagram illustrating a configuration example of a video display system according to an embodiment of the present invention. FIG. 3 is a block diagram illustrating a first configuration example of a video display device. FIG. 3 is a diagram illustrating an example of a video generation device that can be employed in a video projection unit. It is a figure for explaining propagation of image light in a light guide plate. FIG. 3 is a diagram illustrating an example of a diffraction direction of image light by a light guide plate. FIG. 3 is a cross-sectional view illustrating a first configuration example of a video light duplicating unit in the first configuration example of the video display device. FIG. 5 is a cross-sectional view illustrating a second configuration example of the video light duplicating section in the first configuration example of the video display device. FIG. 5 is a cross-sectional view illustrating a third configuration example of the video light duplicating section in the first configuration example of the video display device. It is a block diagram showing the 2nd example of composition of a picture display. It is sectional drawing which shows the 1st example of a structure of the light guide plate containing the image light duplication part in the 2nd example of a structure of an image display device. It is sectional drawing which shows the 2nd example of a structure of the light guide plate containing the image light duplication part in the 2nd example of a structure of an image display device. It is sectional drawing which shows the 3rd example of a structure of the light guide plate containing the image light duplication part in the 2nd example of a structure of an image display device. It is sectional drawing which shows the 4th example of a structure of the light guide plate containing the image light duplication part in the 2nd example of a structure of an image display device. FIG. 13 is a block diagram illustrating a third configuration example of the video display device. It is sectional drawing which shows the example of a structure of the light guide plate in which the image light duplication part in the 3rd example of a structure of an image display apparatus was bonded. It is sectional drawing which shows the 1st modification of the 1st structural example of a video display apparatus. It is sectional drawing which shows the 2nd modification of the 1st structural example of a video display apparatus. It is sectional drawing which shows the modification of the 2nd example of a structure of a video display apparatus.

Hereinafter, a plurality of embodiments according to the present invention will be described with reference to the drawings. In all the drawings for describing each embodiment, the same members are denoted by the same reference numerals in principle, and the repeated description thereof will be omitted. Also, in the following embodiments, the components (including element steps, etc.) are not necessarily essential, unless otherwise specified or considered to be indispensable in principle. Needless to say. In addition, when saying “consisting of A”, “consisting of A”, “having A”, or “including A”, other elements are excluded unless otherwise specified. Needless to say, it doesn't. Similarly, in the following embodiments, when referring to the shapes, positional relationships, and the like of the components, the shapes are substantially the same unless otherwise specified, and in cases where it is clearly considered in principle not to be so. And the like.

<Configuration Example of Video Display System According to One Embodiment of the Present Invention>
FIG. 1 shows a configuration example of a video display system according to an embodiment of the present invention.

The video display system 10 includes a video display device 11, a control device 12, a video signal processing device 13, a power supply device 14, a storage device 15, a sensing device 16, a communication device 18, and an audio processing device 20.

The image display device 11 is a light guide plate type display device using a light guide plate represented by, for example, a head mounted display. The video display device 11 receives a video signal generated by the video signal processing device 13 and supplied via the control device 12, and displays a video based on the video signal to a user. The details of the video display device 11 will be described later.

The control device 12 controls the whole of the video display system 10 as a whole. The control device 12 can realize its function by executing a predetermined program by, for example, a CPU (Central Processing Unit) or a computer.

The video signal processing device 13 generates a video signal to be supplied to the video display device 11. The power supply device 14 supplies power to each device constituting the video display system 10.

The storage device 15 stores a program executed by the control device 12, information necessary for processing of each device constituting the video display system 10, information generated by each device, and the like. The storage device 15 includes, for example, a random access memory (RAM), a flash memory, a hard disk drive (HDD), a solid state drive (SSD), a compact disc-recordable (CD-R), and a digital versatile disk-random access (DVD-RAM). Memory) or a writable and readable storage medium or a storage medium drive.

(4) The sensing device 16 detects the surrounding situation using each sensor connected via the sensor input / output unit 17. As the sensor, for example, a posture sensor, an inclination sensor for detecting the posture and movement of the user, an acceleration sensor, a gaze sensor for detecting the physical condition of the user, a temperature sensor, and a GPS (Global Positioning System) for detecting position information of the user A receiving device, a pressure-sensitive sensor, a capacitance sensor, a barcode reader, and the like can be given.

The communication device 18 uses the communication input / output unit 19 to perform wireless communication using, for example, Bluetooth (registered trademark), Wi-Fi (registered trademark), UHF (Ultra-High Frequency) wave, VHF (Very High Frequency) wave, or the like. Alternatively, communication is performed by connecting to a predetermined communication network (a mobile phone communication network, the Internet, or the like) using wired communication.

The audio processing device 20 is connected to a microphone, an earphone, or the like via the audio input / output unit 21 to input and output an audio signal.

<First configuration example of video display device 11>
Next, FIG. 2 shows a video display device 101 as a first configuration example of the video display device 11.

The video display device 101 includes a video projection unit 200, a video light duplication unit 210, and a light guide plate 220.

The video projection unit 200 receives a video signal generated by the video signal processing device 13 and supplied via the control device 12 and generates video light serving as a video displayed by the video display device 11 based on the video signal. And project it to the subsequent stage. In the case of the figure, the image light projected by the image projection unit 200 is incident on the image light duplication unit 210.

FIG. 3 shows an example of a video generation device that can be employed in the video projection unit 200. FIG. 1A shows a fiber scanning type projector 201 that can be employed in the video projection unit 200. FIG. 2B shows a mirror scanning type projector 202 that can be employed in the video projection unit 200.

The fiber scanning projector 201 shown in FIG. 1A includes a light source unit 900, a fiber 901, a fiber scanning element 902, and a collimating lens 903.

The light source unit 900 emits, for example, laser light. The laser light emitted from the light source unit 900 propagates inside the fiber 901 and exits from the end face 904 of the fiber 901. The light emitted from the fiber 901 passes through the collimator lens 903 and becomes light having high directivity.

The fiber scanning element 902 attached to the fiber 901 vibrates the end face 904 of the fiber 901 and scans the light emitted from the fiber 901. The fiber scanning type projector 201 can project an image by synchronizing the intensity of the laser light output from the light source unit 900 and the vibration of the end surface 904 by the fiber scanning element 902 with the image signal.

ミ ラ ー The mirror scanning type projector 202 shown in FIG. 2B includes a light source unit 900 and a scanning element 911.

The scanning element 911 has a scanning mirror (not shown). The laser light output from the light source unit 900 has directivity, and the laser light enters a scanning mirror of the scanning element 911 and is reflected. At this time, the scanning element 911 can scan the reflected light by vibrating the scanning mirror. The mirror scanning projector 202 can project an image by synchronizing the intensity of the laser light output from the light source unit 900 and the vibration of the scanning element 911 with the image signal.

戻 る Return to FIG. The image light duplicating unit 210 duplicates the light beam of the image light into two or more light beams while substantially preserving the angle of view of the incident image light, and outputs the duplicated two or more image light to the light guide plate 220. The details of the video light duplication unit 210 will be described later.

The light guide plate 220 includes a light input unit 221 into which the image light from the image light duplicating unit 210 enters, and a light output unit 222 that emits the image light to the user's eyes.

Next, FIG. 4 is a diagram for explaining the propagation of image light in the light guide plate 220.

The image light k from the image light duplicating unit 210 enters the inside of the light guide plate 220 from the light input unit 221 (the upper surface in the figure), and all the light on the inner reflection surfaces 223 and 224 facing the xz plane of the light guide plate 220 is opposed. The light propagates inside the light guide plate 220 by reflection.

The light guide plate 220 has a function of enlarging the pupil size, which is the light beam diameter of the image light displayed on the image display device 101, and duplicates the image light k incident on the light guide plate 220 from the light input unit 221. The light is output from the light output unit 222 (the lower surface in the figure). Thereby, the image light of the pupil size φ2 larger than the pupil size φ1 which is the light beam diameter of the image light k incident on the light guide plate 220 from the light input unit 221 (three replicated image lights k in the case of FIG. 3). Can be output from the light output unit 222.

Next, FIG. 5 is a diagram illustrating an example of the light guide plate 220. It should be noted that the illustration of the image light duplication unit 210 provided between the image projection unit 200 and the light guide plate 220 is omitted in FIG.

光 A light guide plate 801 which is an example of the light guide plate 220 shown in FIG. 9A includes three diffraction regions 802, 803, and 804.

The diffraction region 802 has a structure that diffracts light substantially parallel to the y-axis in a direction substantially parallel to the z-axis. The diffraction region 803 has a structure that diffracts light substantially parallel to the z-axis in the xz plane in a direction substantially parallel to the x-axis. The diffraction region 804 has a structure that diffracts light substantially parallel to the x-axis in a direction substantially parallel to the y-axis. The pitches of the diffraction structures of the diffraction region 802 and the diffraction region 804 are substantially equal to each other, and the pitch of the diffraction structure of the diffraction region 803 is substantially equal to 1 / √2 times the pitch of the diffraction structure of the diffraction region 802.

In the light guide plate 801, the image light from the image projection unit 200 enters the diffraction area 802 corresponding to the light input unit 221. The image light incident on the diffraction region 802 is diffracted, taken into the light guide plate 801, totally internally reflected and guided inside the light guide plate 801, and reaches the diffraction region 803. Part of the image light that has reached the diffraction region 803 is diffracted by the diffraction region 803, and the image light that has not been diffracted is totally reflected inside the light guide plate 801 and reaches the diffraction region 803 again. Each time the light reaches the diffraction region 803, the image light is duplicated, and the duplicated image light is totally reflected and guided inside the light guide plate 801, and reaches the diffraction region 804 corresponding to the light output unit 222.

Part of the image light that has reached the diffraction area 804 is diffracted by the diffraction area 804, and the image light that has not been diffracted is totally reflected inside the light guide plate 801 and reaches the diffraction area 804 again. Each time the light reaches the diffraction region 804, the image light is duplicated and emitted from the light guide plate 801.

Therefore, according to the light guide plate 801, the pupil size, which is the light beam diameter of the image light, can be enlarged in the two-dimensional direction. Although the light guide plate 801 includes three diffraction regions 802 to 804, for example, two diffraction regions may be provided in the light guide plate and the directions and the periods (pitch) of the diffraction structures of the two diffraction regions may be substantially the same. . Thereby, the structure of the light guide plate can be simplified, and the cost of the light guide plate can be reduced.

Next, a light guide plate 811 which is an example of the light guide plate 220 shown in FIG. 2B includes two diffraction regions 812 and 813.

The diffraction region 812 has a structure that diffracts light substantially parallel to the y-axis in a direction substantially parallel to the x-axis in the xz plane. The diffraction region 813 has a structure in which light substantially parallel to the x-axis is diffracted in two directions of approximately 60 degrees and approximately −60 degrees counterclockwise from the x-axis on the xz plane. The pitch of the diffraction structure in the diffraction region 812 and the pitch of the diffraction structure in the two directions of the diffraction region 813 are substantially equal to each other.

In the light guide plate 811, the image light from the image projection unit 200 enters the diffraction area 812 corresponding to the light input unit 221. The image light incident on the diffraction region 812 is diffracted, taken into the light guide plate 811, totally reflected and guided inside the light guide plate 811, and reaches the diffraction region 813 corresponding to the light output unit 222. The diffractive region 813 has a structure that diffracts image light in two directions. In the process of total reflection and light guiding inside the light guide plate 811, when diffracted once by each of the two-directional diffractive structures of the diffractive region 813, The image light exits from the light guide plate 811.

Therefore, the pupil size, which is the light beam diameter of the image light, can also be enlarged in the two-dimensional direction by the light guide plate 811.

Next, a light guide plate 821, which is an example of the light guide plate 220 shown in FIG. 9C, includes an incident surface 822 and a plurality of partially reflecting surfaces 823.

The plurality of partial reflecting surfaces 823 are a plurality of beam splitter surfaces that are parallel to each other, reflect at least part of incident light, and transmit the rest.

In the light guide plate 821, the image light from the image projection unit 200 enters the incident surface 822 corresponding to the light input unit 221. The image light incident on the incident surface 822 is totally reflected and guided inside the light guide plate 821, and reaches a plurality of partially reflective surfaces 823. The image light is emitted from the light output surface 824 corresponding to the light output unit 222 by reflecting the image light on each of the beam splitter surfaces constituting the plurality of partial reflection surfaces 823.

Therefore, according to the light guide plate 821, the pupil size, which is the light beam diameter of the image light, can be enlarged in a one-dimensional direction.

As described above, part of the image light emitted from the light guide plates 801, 811, and 821 enters the user's eyes 120. The user can visually recognize the image displayed on the image display device 101 by perceiving the light that has entered the eye 120.

Note that the pupil size φ2 (FIG. 4) of the image light output from the light output unit 222 of the light guide plate 220 is changed by the function of enlarging the pupil size of the light guide plate 220 so that the pupil size of the image light incident on the light guide plate 220 is reduced. Since it is larger than φ1 (FIG. 4), compared with the case where the user directly sees the image light that enters the light guide plate 220 without passing through the light guide plate 220, the case where the image light emitted from the light guide plate 220 is viewed This makes it possible to increase the area (eye box) where the user can visually recognize the image when the user's eyes 120 move.

However, an image generation device that scans with directional light (laser light) and generates an image, such as the fiber scanning projector 201 and the mirror scanning projector 202 shown in FIG. In this case, the exit pupil diameter of the image light is substantially equal to the diameter of the directional light, and is about 0.1 to 2.0 mm.

Since the exit pupil diameter of the image light of about 0.1 to 2.0 mm is smaller than the interval of about 2 mm to 8 mm of the plurality of image lights output from the light guide plate 220, the plurality of images output from the light guide plate 220 are small. When the lights do not overlap with each other and the user's eyes are located in the gap between the plurality of image lights, the image light may or may not enter the pupil of the user's eyes. In this case, the user may not be able to visually recognize at least a part of the image, or a part of the image may be noticeably dark.

、 In order to prevent such a situation from occurring, in the image display device 101, the image light duplication unit 210 is provided between the image projection unit 200 and the light guide plate 220. Hereinafter, the image light duplication unit 210 will be described in detail.

<First Configuration Example of Video Light Duplicating Unit 210>
Next, FIG. 6 is a cross-sectional view illustrating a first configuration example of the video light duplication unit 210 in the video display device 101.

The first configuration example of the video light duplication unit 210 includes the video light duplication prism 301. The image light duplicating prism 301 is formed of a transparent glass material or resin, and includes an input surface 302, an output surface 303, and at least two or more substantially flat and substantially parallel image light branch surfaces 304. In the case of the figure, the image light duplicating prism 301 includes two image light splitting surfaces 304A and 304B.

In the image light duplicating prism 301, the image light from the image projection unit 200 enters from the input surface 302 and reaches the image light splitting surface 304A. The image light splitting surface 304A reflects at least a part of the incident light and transmits the rest. Therefore, the image light that has reached and transmitted the image light branching surface 304 </ b> A exits from the output surface 303. Further, the image light that has reached the image light branch surface 304A and is reflected reaches the image light branch surface 304B. The image light splitting surface 304B reflects at least a part of the light. Therefore, the light that reaches and is reflected by the image light branch surface 304 </ b> B exits from the output surface 303.

Since the image light splitting surfaces 304A and 304B are both substantially flat and substantially parallel to each other, the image light duplicating prism 301 includes two image light beams having substantially the same angle of view as the image light incident on the image light duplicating prism 301. And output it.

２Each of the two image lights output by the image light duplicating prism 301 enters the light input unit 221 of the light guide plate 220. The two video lights incident on the light input unit 221 are duplicated by the function of expanding the pupil size of the light guide plate 220 and output from the light output unit 222.

(2) The two image lights output by the image light duplicating prism 301 enter different positions of the light input unit 221 of the light guide plate 220, and are output from different positions of the light output unit 222. Therefore, the gap between the video lights output from the light guide plate 220 is reduced. As a result, the image light enters the pupil of the user's eye, and the user can visually recognize the entire image.

It is preferable that the image light splitting surface 304B (the image light splitting surface 304 of the plurality of image light splitting surfaces 304 where the image light reaches the end) reflects all the image light. This makes it possible to increase the light use efficiency.

Further, when the energy reflectance (hereinafter, abbreviated to reflectivity) of the image light branch surface 304A is RA and the reflectivity of the image light branch surface 304B is RB, (1-RA) is substantially equal to RA × RB. Thus, it is desirable to form the image light branch surfaces 304A and 304B.

In particular, when the image light splitting surface 304B totally reflects the image light, that is, when RB = 1, it is preferable that RA = 0.5. Thereby, the intensities of the two image light beams emitted from the image light duplicating prism 301 become substantially equal to each other, and the image viewed by the user can be made more uniform.

In addition, in the case of the drawing, the image light duplicating prism 301 has been described as including two image light branch surfaces 304, but may have two or more image light branch surfaces 304. Even when the image light duplicating prism 301 includes two or more image light branch surfaces 304, all the image light branch surfaces 304 are formed to be substantially flat and substantially parallel to each other.

For example, the number of image light splitting surfaces 304 is N, and among the N image light splitting surfaces 304, the first, second,... In this case, the image light incident from the input surface 302 enters the first image light splitting surface 304. At least a part of the light incident on the first image light branch surface 304 passes through the first image light branch surface 304, exits from the output surface 303, and at least the light incident on the first image light branch surface 304. Part of the light is reflected by the first image light splitting surface 304 and enters the second image light splitting surface 304. For an integer k equal to or greater than 2 and equal to or less than (N-1), at least a portion of the light incident on the k-th image light splitting surface 304 is reflected by the k-th image light splitting surface 304 and exits from the output surface 303. At least a part of the light incident on the k-th image light splitting surface 304 passes through the k-th image light splitting surface 304 and is incident on the (k + 1) th image light splitting surface 304. At least a part of the light incident on the N-th image light branch surface 304 is reflected by the N-th image light branch surface 304 and exits from the output surface 303. Thus, the image light duplicating prism 301 can duplicate and output N pieces of image light having substantially the same angle of view as the image light incident on the image light duplicating prism 301.

Further, among the first to N-th image light splitting surfaces 304, the reflectance of the first image light splitting surface 304 is the highest, and the reflectance of the second to N-th image light splitting surfaces 304 is higher than the input surface. It is good to constitute so that it may become low, so that it is near. Preferably, the reflectance of the first image light splitting surface 304 is (N-1) / N, and the reflectance of the k-th image light splitting surface 304 is 1 for an integer k of 2 or more and N or less. / (N−k + 1). Thereby, it is possible to make the video visually recognized by the user more uniform.

Further, the image light duplicating prism 301 is incident on an end surface other than the output surface 303 of the image light duplicating prism 301 before the image light incident on the image light duplicating prism 301 from the input surface 302 is incident on the image light splitting surface 304. It is desirable to be configured not to do so. Thereby, generation of stray light can be prevented.

Further, the image light duplicating prism 301 sets the light reflected by the first image light splitting surface 304 before being reflected by the second to N image light splitting surfaces 304 other than the first image light splitting surface 304. It is desirable to configure so as not to enter the end face of the image light duplicating prism 301. Thereby, generation of stray light can be prevented.

As another image light duplicating prism 301, an image light duplicating prism 301 configured so that light incident on the image light duplicating prism 301 and reflected by the first image light splitting surface 304 exits from the output surface 303 is used. Is also good. For example, video light incident from the input surface 302 is incident on the first video light splitting surface 304. For an integer k equal to or greater than 1 and equal to or less than (N−1), at least a portion of the light incident on the k-th image light branch surface 304 is reflected by the k-th image light branch surface 304 and exits from the output surface 303. At least a part of the light incident on the k-th image light splitting surface 304 passes through the k-th image light splitting surface 304 and is incident on the (k + 1) th image light splitting surface 304. At least a part of the light incident on the N-th image light branch surface 304 is reflected by the N-th image light branch surface 304 and exits from the output surface 303. Thereby, the degree of freedom of arrangement can be increased. Further, it is preferable that the reflectance of the first to N-th image light splitting surfaces 304 decreases as the position is closer to the input surface. Preferably, for an integer k of 1 or more and N or less, the reflectance of the k-th image light splitting surface 304 may be 1 / (N−k + 1). Thereby, it is possible to make the video visually recognized by the user more uniform.

Further, the image light duplicating prism 301 has a case where the aperture size of the image projecting unit 200 for emitting image light is φPJ (not shown) and the arrangement interval of the N image light splitting surfaces 304 of the image light duplicating prism 301 is DistP. , DistP may be configured to be substantially equal to φPJ or smaller than φPJ. Thereby, the two or more image lights output by the image light duplicating prism 301 overlap each other, and the image viewed by the user can be made more uniform.

Further, from another viewpoint, when the interval between a plurality of image lights output from the light guide plate 220 is set to Dwg (not shown) by the function of enlarging the pupil size of the light guide plate 220, DistP is It may be configured to be approximately equal to 1 / N of Dwg or approximately equal to an integral multiple of 1 / N of Dwg. Thereby, the gap between the image lights output from the light guide plate 220 can be further reduced, and the image visually recognized by the user can be made more uniform.

<Second Configuration Example of Video Light Duplicating Unit 210>
Next, FIG. 7 is a cross-sectional view illustrating a second configuration example of the video light duplication unit 210 in the video display device 101.

The second configuration example of the image light duplication unit 210 includes the image light duplication diffraction element 311. The image light duplication diffraction element 311 is formed of a transparent glass material or resin, and includes an input surface 312 and an output surface 313. The input surface 312 includes a diffraction region 314 that diffracts at least some light. The output surface 313 includes a plurality of diffraction regions 315 that diffract at least a part of the light. In the case of the drawing, the output surface 313 includes two diffraction regions 315A and 315B.

方向 The directions and the periods (pitches) of the diffraction structures of the diffraction region 314 and the diffraction region 315 are substantially the same. In the case of the drawing, the direction of the grooves of the diffraction structure in the diffraction regions 314 and 315 is the z-axis direction, and the direction of the pitch is the x-axis direction.

In the image light duplication diffraction element 311, the image light from the image projection unit 200 enters the diffraction area 314 of the input surface 312. The diffraction region 314 generates zero-order light, first-order light, and -1st-order light. The 0th-order light, the 1st-order light, and the -1st-order light emitted from the diffraction region 314 propagate inside the image light duplication diffraction element 311 respectively. The zero-order light from the diffraction region 314 is output to the light guide plate 220 from a region of the output surface 313 where the diffraction region 315 is not provided. The -1st-order light from the diffraction area 314 reaches the diffraction area 315A, undergoes first-order diffraction, and is output to the light guide plate 220. The first-order light from the diffraction region 314 reaches the diffraction region 315B, is diffracted by −1st order, and output to the light guide plate 220.

As described above, the directions and the periods (pitch) of the diffraction structures of the diffraction region 314 and the diffraction region 315 are configured to be substantially the same. This allows the image light duplication diffraction element 311 to duplicate and output three image lights having substantially the same angle of view as the image light incident on the image light duplication diffraction element 311.

回 折 It is desirable that diffraction efficiencies of the diffraction region 314 other than the three diffraction orders of the 0th-order diffraction, the 1st-order diffraction, and the -1st-order diffraction be substantially zero. Further, it is desirable that both the first-order diffraction efficiency of the diffraction region 315A and the −1st-order diffraction efficiency of the diffraction region 315B are substantially 1. Thereby, light use efficiency can be improved.

Further, it is desirable that the diffraction efficiencies of the 0th-order diffraction, the 1st-order diffraction, and the -1st-order diffraction of the diffraction region 314 are substantially equal to each other. Thereby, the intensities of the three image lights output from the image light duplication diffraction element 311 can be made substantially equal, and the image viewed by the user can be made more uniform.

Further, a point that internally divides the center between the diffraction area 315A and the center of the diffraction area 315B by 1: 1 and a vertical line extending from the center of the diffraction area 314 to the output plane 313 and the output plane 313. The intersections are desirably at substantially the same position. Thereby, the structure of the image light duplication diffraction element 311 can be simplified, and the cost of the image light duplication diffraction element 311 can be reduced.

In another aspect, a point that internally divides 1: 1 between the center point of the image light incident on the diffraction area 315A and the center point of the image light incident on the diffraction area 315B, and the image incident on the diffraction area 314 It is desirable that the intersections of the perpendiculars descending from the central point of the light to the output surface 313 and the output surface 313 be substantially at the same position. Thereby, the structure of the image light duplication diffraction element 311 can be simplified, and the cost of the image light duplication diffraction element 311 can be reduced.

In the image light duplication diffraction element 311, the aperture size of the image projection unit 200 for emitting image light is φPJ, and the distance between the center point of the diffraction area 315 A and the center point of the diffraction area 315 B is DistG 1 (both are not shown). In this case, DistG1 is desirably approximately twice as large as φPJ or smaller than approximately twice. Thus, the three image lights output from the image light duplication diffraction element 311 overlap each other, and the image viewed by the user can be made more uniform.

From another viewpoint, when the distance between the center point of the image light incident on the diffraction area 315A and the center point of the image light incident on the diffraction area 315B is DistG2 (not shown), DistG2 is approximately 2 of φPJ. It is desirable to be smaller than twice or substantially twice. Accordingly, the three image lights output by the image light duplication diffraction element 311 overlap each other, and the image viewed by the user can be made more uniform.

In the above description, the diffraction region 314 has been described as outputting three orders of diffracted light, that is, the 0th-order diffraction, the 1st-order diffraction, and the -1st-order diffraction. Two-order diffracted light such as the second-order diffraction may be output. Thereby, the structure of the image light duplication diffraction element 311 can be simplified, and the cost of the image light duplication diffraction element 311 can be reduced.

Alternatively, the diffraction region 314 may output N (N is an integer of 2 or more) orders of diffracted light such as 0th-order diffraction, 1st-order diffraction, -1st-order diffraction, 2nd-order diffraction, and -2nd-order diffraction. . The light diffracted in the k-th order in the diffraction area 314, where k is an integer, is diffracted in the −k-th order in the diffraction area 315 provided in the output surface 313, and is output from the image light duplication diffraction element 311. As a result, the image light duplicating diffraction element 311 can duplicate and output N pieces of image light having substantially the same angle of view as the image light incident on the image light duplicating diffraction element 311, and display the image visually recognized by the user. Can be made more uniform.

The image light duplication diffraction element 311 may be configured so that, on the output surface 313, a region where the light diffracted by the k-th order in the diffraction region 314 reaches a diffraction region having a high diffraction efficiency of −k-th order diffraction. Further, it is desirable that a region of the output surface 313 to which the light diffracted (not diffracted) by the 0th order in the diffraction region 314 reaches does not have a diffraction region. This makes it possible to increase the light use efficiency.

Further, a distance DistG3 (not shown) between adjacent image lights that reach the output surface 313 by diffracting in the diffraction area 314 is substantially equal to the opening size φPJ of the image projection unit 200 for emitting the image light, or φPJ. Desirably smaller. Thereby, the two or more image lights output from the image light duplication diffraction element 311 overlap each other, and the image visually recognized by the user can be made more uniform.

Further, from another viewpoint, when an interval between a plurality of image lights output from the light guide plate 220 is set to Dwg by a function of enlarging a pupil size of the light guide plate 220, DistG3 is substantially equal to 1 / N of Dwg, or Dwg. The image light duplication diffraction element 311 is preferably configured to be substantially equal to an integral multiple of 1 / N of the above. Thereby, the gap between the image lights output from the light guide plate can be further reduced, and the image visually recognized by the user can be made more uniform.

<Third Configuration Example of Video Light Duplicating Unit 210>
Next, FIG. 8 is a cross-sectional view illustrating a third configuration example of the video light duplication unit 210 in the video display device 101.

The third configuration example of the video light duplication unit 210 includes a video light duplication beam splitter 321. The image light duplication beam splitter 321 is formed of a transparent glass material or resin, and has an input surface 322 and an output surface 323. The image light duplication beam splitter 321 is formed such that the angle formed between the output surface 323 and the light input unit 221 is larger than 0 degree, and the input surface 322 and the output surface 323 are parallel to each other.

In the image light duplication beam splitter 321, image light from the image projection unit 200 enters from the input surface 322, and at least a part of the incident image light propagates inside the image light duplication beam splitter 321. The video light that has propagated inside the video light duplication beam splitter 321 reaches the output surface 323. The output surface 323 transmits at least a part of the light and reflects at least a part of the light. The light transmitted through the output surface 323 exits from the image light duplication beam splitter 321. The light reflected on the output surface 323 propagates inside the image light duplication beam splitter 321 to reach the input surface 322, is reflected on the input surface 322, and reaches the output surface 323 again. Each time the light incident from the input surface 322 reaches the output surface 323, the video light exits from the output surface 323.

As described above, since the input surface 322 and the output surface 323 are formed so as to be parallel to each other, the image light duplication beam splitter 321 is substantially the same as the image light incident on the image light duplication beam splitter 321. It becomes possible to duplicate and output at least two or more video lights having corners.

透過 It is desirable that the transmittance of an area of the input surface 322 where the image light from the image projection unit 200 is incident is approximately 1. Thereby, the light use efficiency can be increased.

反射 In addition, it is desirable that the reflectance of a region of the input surface 322 where the image light reflected by the output surface 323 enters is approximately 1. Thereby, light use efficiency can be increased.

A region in the output surface where the image light incident from the input surface 322 reaches is a first arrival region, and k is an integer of 1 or more. The image light reflected by the k-th arrival region is reflected by the input surface 322 again. An area in the output plane reaching the output plane 323 is defined as a (k + 1) th arrival area. The output surface 323 is provided from the first reaching region to the N-th reaching region, where N is an integer of 2 or more, and the image light duplication beam splitter 321 outputs N image lights. In this case, it is desirable that the reflectance of the k-th reaching area is larger than the reflectance of the (k + 1) -th reaching area. Preferably, the reflectance of the k-th reaching area is (N−k) / (N−k + 1). Thereby, the intensities of the image light output from the image light duplication beam splitter 321 become substantially equal to each other, so that the image visually recognized by the user can be made more uniform.

From another viewpoint, it is desirable that the image light duplication beam splitter 321 be configured so that the entire surface of at least one of the input surface 322 and the output surface 323 has a substantially uniform reflectance. As a result, the cost of the image light duplication beam splitter 321 can be reduced.

According to the image display device 101 including the image light duplicating unit 210 described above, the image projecting unit 200 displays an image having a small exit pupil such as the fiber scanning projector 201 or the mirror scanning projector 202 shown in FIG. Even when the generation device is employed, the image light is incident on the pupil of the user's eye, so that the user can visually recognize the entire image. In other words, the image projection unit 200 employs an image generation device with a small exit pupil, such as the fiber scanning projector 201 or the mirror scanning projector 202 shown in FIG. 3, so that the user can view the entire image. Thus, the size of the video display device 11 can be reduced.

<Second configuration example of video display device>
Next, FIG. 9 shows a video display device 102 as a second configuration example of the video display device 11. Note that among the components of the video display device 102, those that are common to the components of the video display device 101 (FIG. 2) are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

The image display device 102 includes the image projection unit 200 and the light guide plate 400. The light guide plate 400 includes a light input unit 221, a video light duplication unit 230, and a light output unit 222.

In the image display device 102, image light from the image projection unit 200 enters the light guide plate 400 from the light input unit 221, propagates inside the light guide plate 400, and enters the image light duplication unit 230. The image light duplicating unit 230 duplicates and outputs at least two light beams of the image light while substantially preserving the angle of view of the incident image light. The image light duplicated by the image light duplication unit 230 propagates inside the light guide plate 400 and exits from the light output unit 222 to the outside of the light guide plate 400.

<Configuration Example of Light Guide Plate 400 Including Image Light Duplicating Unit 230>
Next, a plurality of configuration examples of the light guide plate 400 including the image light duplication unit 230 will be described with reference to FIGS.

FIG. 10 is a cross-sectional view illustrating a first configuration example of the light guide plate 400. A light guide plate 410, which is a first configuration example of the light guide plate 400, includes a light input unit 221, a light output unit 222, and transparent flat plates 401A, 401B, and 402.

(4) The transparent flat plates 401A and 401B correspond to the image light duplication unit 230. The transparent flat plates 401A, 401B, 402 are each formed of a transparent glass material or resin. The transparent flat plate 401A and the transparent flat plate 401B are bonded together by a transparent adhesive or an optical contact on a bonding surface 403 parallel to the xz plane. Similarly, the bonded transparent flat plates 401A and 401B and the transparent flat plate 402 are bonded by a transparent adhesive or an optical contact on a bonding surface 404 parallel to the yz plane.

Further, when the thickness of the transparent flat plate 401A is t1, the thickness of the transparent flat plate 401B is t2, and the thickness of the transparent flat plate 402 is tt, the thickness tt of the transparent flat plate 402 is equal to the thickness of the transparent flat plates 401A and 401B. It has a relationship substantially equal to the sum t1 + t2.

In the light guide plate 410, the image light from the image projection unit 200 enters the light guide plate 410 from the light input unit 221. Light that has entered the inside of the light guide plate 410 propagates through the inside of the transparent flat plate 401A and reaches the bonding surface 403. At least a part of the bonding surface 403 reflects at least a part of the image light and transmits at least a part of the image light. Thus, the image light that has reached the bonding surface 403 is duplicated into two beams depending on whether the light is reflected or transmitted by the bonding surface 403.

映像 The image light reflected on the bonding surface 403 is totally reflected on the total reflection surface 405A of the transparent flat plate 401A, and reaches the bonding surface 403 again. On the other hand, the image light transmitted through the bonding surface 403 is totally reflected by the total reflection surface 405B of the transparent flat plate 401B, and reaches the bonding surface 403 again. Each time the image light reaches the bonding surface 403, it is duplicated into two depending on whether it is reflected or transmitted by the bonding surface 403. As a result, the image light that has entered the image light duplicating section 230 is duplicated and reaches the bonding surface 404. The plurality of image lights that have reached the bonding surface 404 are incident on the transparent flat plate 402 from the image light duplicating section 230 and reach the light output section 222.

The plurality of image lights from the image light duplicating section 230 are further duplicated by the function of enlarging the pupil size of the light guide plate 410 and output from different positions of the light output section 222. Therefore, the gap between the video lights emitted from the light guide plate 410 is reduced. As a result, the image light enters the pupil of the user's eye, and the user can visually recognize the entire image.

When the thickness t1 of the transparent flat plate 401A and the thickness t2 of the transparent flat plate 401B are substantially equal to each other, it is possible to prevent the transparent flat plate 401A and the transparent flat plate 401B from becoming thin, and to increase the strength of the light guide plate 410. It becomes possible. Also, in this case, the image light duplication unit 230 can duplicate the image light into two lines.

Further, it is desirable that the reflectance of the bonding surface 403 of the transparent flat plates 401A and 401B is approximately 0.5. Accordingly, the intensities of the plurality of light beams output from the image light duplicating section 230 can be made substantially equal to each other, and the image visually recognized by the user can be made more uniform.

From another viewpoint, when the relationship between the thickness t1 of the transparent flat plate 401A and the thickness t2 of the transparent flat plate 401B is set to 0.2 ≦ t2 / t1 <5, the strength of the light guide plate 410 is not reduced. Thus, it is possible to increase the number of image lights output by the image light duplicating section 230.

For example, when t2 / t1 = 0.5 or t2 / t1 = 2, the image light duplication unit 230 can duplicate the image light into three lines. Thereby, the gap between the image lights emitted from the light guide plate 410 can be further reduced, and the image visually recognized by the user can be made more uniform.

Next, FIG. 11 is a cross-sectional view illustrating a second configuration example of the light guide plate 400. The light guide plate 420, which is a second configuration example of the light guide plate 400, is obtained by adding a transparent flat plate 406 directly below the light input unit 221 to the light guide plate 410 (FIG. 10).

The transparent flat plate 406 is formed of a transparent glass material or resin. The bonded transparent flat plates 401A and 401B and the transparent flat plate 406 are bonded by a transparent adhesive or an optical contact on a bonding surface 407 parallel to the yz plane.

In the light guide plate 420, the image light from the image projection unit 200 enters the light guide plate 420 from the light input unit 221. The light that has entered the inside of the light guide plate 410 propagates through the inside of the transparent flat plate 406 and enters the image light duplication unit 230 from the bonding surface 407. The propagation of the video light after entering the video light duplicating section 230 is the same as that of the light guide plate 410, and thus the description is omitted.

The image light duplicated by the image light duplicating unit 230 is further duplicated by the function of enlarging the pupil size of the light guide plate 420 and output from different places of the light output unit 222. Therefore, the gap between the image lights emitted from the light guide plate 420 is reduced. As a result, the image light enters the pupil of the user's eye, and the user can visually recognize the entire image.

FIG. 12 is a cross-sectional view illustrating a third configuration example of the light guide plate 400. The light guide plate 430, which is a third configuration example of the light guide plate 400, includes a light input unit 221, a light output unit 222, a transparent flat plate 441, and a transparent flat plate 442.

The image light duplication unit 230 is realized by the transparent flat plate 441 and a part of the transparent flat plate 442.

(4) The transparent flat plate 441 and the transparent flat plate 442 are bonded by a transparent adhesive or an optical contact on a bonding surface 443 parallel to the xz plane. At least a part of the bonding surface 443 reflects at least a part of the image light and transmits at least a part of the image light.

映像 In the light guide plate 430, image light from the image projection unit 200 enters the light guide plate 440 from the light input unit 221 and reaches the bonding surface 443. On the bonding surface 443, the image light is duplicated into two depending on whether the image light is reflected or transmitted. Thereby, the image light incident on the image light duplicating section 230 is duplicated into a plurality. The plurality of image lights output from the image light duplicating unit 230 are duplicated by the function of enlarging the pupil size of the light guide plate 430 and output from different positions of the light output unit 222. Therefore, the gap between the video lights output from the light guide plate 430 is reduced. As a result, the image light enters the pupil of the user's eye, and the user can visually recognize the entire image.

In the light guide plates 410, 420, and 430 described above, the image light duplicating unit 230 is formed by two transparent flat plates, but the image light duplicating unit 230 may be formed by two or more transparent flat plates.

Next, FIG. 13 is a cross-sectional view illustrating a fourth configuration example of the light guide plate 400. A light guide plate 440, which is a fourth configuration example of the light guide plate 400, includes a light input unit 221, a light output unit 222, a transparent flat plate 402, and three transparent flat plates 421A to 421C.

The image light duplication unit 230 is realized by three transparent flat plates 421A to 421C. The transparent flat plates 421A and 421B forming the image light duplication unit 230 are bonded together at a bonding surface 423A parallel to the xz plane, and the transparent flat plates 421B and 421C are bonded together at a bonding surface 423B parallel to the xz plane. Bonded together by an agent or an optical contact. The bonded transparent flat plates 421A to 421C and the transparent flat plate 402 are bonded together by a transparent adhesive or an optical contact on a bonding surface 424 parallel to the yz plane.

When the thickness of the transparent flat plate 421A is t1, the thickness of the transparent flat plate 421B is t2, the thickness of the transparent flat plate 421C is t3, and the thickness of the transparent flat plate 402 is tt, the thickness tt of the transparent flat plate 402 is The sum of the thicknesses of 421A, 421B, and 421C is substantially equal to t1 + t2 + t3.

At least a part of each of the bonding surfaces 423A and 423B reflects at least a part of the image light and transmits at least a part of the image light.

Note that if the number of transparent flat plates forming the image light duplicating unit 230 is further increased, the number of image light to be duplicated by the image light duplicating unit 230 can be increased. Thereby, the gap between the image lights output from the light guide plate 440 can be further reduced, and the image visually recognized by the user can be made more uniform.

According to the video display device 102 including any one of the light guide plates 410 to 440 described above, in addition to the operation and effect obtained by the video display device 101 described above, the image display device 102 is provided between the video projection unit 200 and the light guide plate 400. Since there is no need to dispose optical components, the size of the image display device 11 can be further reduced.

<Third Configuration Example of Video Display Device>
Next, FIG. 14 shows a video display device 103 which is a third configuration example of the video display device 11. Among the components of the video display device 103, components common to the components of the video display device 101 (FIG. 2) are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

The image display device 103 includes the image projection unit 200, the image light duplication unit 250, and the light guide plate 700. The image light duplicating section 250 is attached to the light guide plate 700 by a transparent adhesive or an optical contact.

The light guide plate 700 includes a light input unit 221, a total reflection light guide unit 240, and a light output unit 222.

In the image display device 103, image light from the image projection unit 200 enters the light guide plate 700 from the light input unit 221, and is totally reflected and guided by the total reflection light guide unit 240. Then, in the process of total reflection light guiding, the image light propagates to the image light duplication unit 250. The image light duplication unit 250 duplicates and outputs at least two or more light beams while substantially preserving the angle of view of the transmitted image light. The image light output from the image light duplicating unit 250 is again incident on the total reflection light guiding unit 240 and is totally reflected and guided. The image light emitted from the total reflection light guide 240 is emitted from the light output unit 222 to the outside of the light guide plate 700.

FIG. 15 is a cross-sectional view illustrating a configuration example of the light guide plate 700 to which the image light duplication unit 250 is attached.

(4) The image light duplicating section 250 is composed of a transparent flat plate 431A formed of a transparent glass material or resin. The total reflection light guide 240 is composed of a transparent flat plate 432 formed of a transparent glass material or resin.

(4) The transparent flat plate 431A and the transparent flat plate 432 are bonded by a transparent adhesive or an optical contact on a bonding surface 433 parallel to the xz plane.

In the light guide plate 700, the image light from the image projection unit 200 enters the inside of the light guide plate 700 from the light input unit 221 and guides the inside of the transparent flat plate 432 (total reflection light guide unit 240) by total reflection. The image light reaches the bonding surface 433 during the process of total reflection light guiding inside the transparent flat plate 432. At least a part of the bonding surface 433 transmits at least a part of the image light and reflects at least a part of the light. The image light transmitted through the bonding surface 433 is totally reflected and guided inside the transparent flat plate 431 and reaches the bonding surface 433 again. On the other hand, the image light reflected on the bonding surface 433 is totally reflected and guided inside the transparent flat plate 432 and reaches the bonding surface 433 again. Therefore, the image light is duplicated each time it reaches the bonding surface 433, whereby the image light duplicating unit 250 can output a plurality of image lights.

(4) The plurality of image lights output by the image light duplicating unit 250 are duplicated by the function of enlarging the pupil size of the light guide plate 700, and output from different positions of the light output unit 222. Therefore, the gap between the image lights output from the light guide plate 700 is reduced. As a result, the image light enters the pupil of the user's eye, and the user can visually recognize the entire image.

Note that the thickness t1 of the transparent flat plate 431A and the thickness t2 of the transparent flat plate 432 are formed so as to satisfy a relationship of t1 <t2. Thereby, the distance of one round trip of total reflection inside the transparent flat plate 431A is shortened, the number of copies of the image light by the image light duplicating unit 250 can be increased, and the image viewed by the user can be made more uniform. Becomes

According to the video display device 103 including the light guide plate 700 described above, in addition to the functions and effects obtained by the above-described video display device 101, the optical components disposed between the video projection unit 200 and the light guide plate 700 Since it becomes unnecessary, the size of the image display device 11 can be further reduced.

<First Modification of Video Display Device 101>
Next, a first modified example of the video display device 101 which is a first configuration example of the video display device 11 will be described. The image display apparatus 101 described above is configured such that the image light from the image projection unit 200 is duplicated by the image light duplication unit 210 and is incident on one light guide plate 220, as shown in FIGS. However, the plurality of image lights duplicated by the image light duplication unit 210 may be modified so as to be incident on the plurality of light guide plates 220.

FIG. 16 shows a first modification of the video display device 101. The first modified example includes three light guide plates 220A, 220B, and 220C that are arranged so as to overlap in the y-axis direction.

(4) The light input unit 221A of the light guide plate 220A captures at least a part of the image light incident from the image light duplication unit 210 into the light guide plate 220A and transmits at least a part of the light. The light input part 221B of the light guide plate 220B captures at least a part of the image light transmitted through the light input part 221A into the light guide plate 220B and transmits at least a part thereof. The light input unit 221C of the light guide plate 220C takes at least a part of the image light transmitted through the light input unit 221B into the light guide plate 220C.

(4) The light guide plates 220A to 220C are made to have characteristics of transmitting light of different wavelengths. For example, the light guide plate 220A has a property to propagate light in the blue band, the light guide plate 220B has a property to propagate light in the green band, and the light guide plate 220C has a property to propagate light in the red band. To have.

This allows the image light to propagate through any of the light guide plates 220A to 220C according to the color of the image light. Further, since the wavelength of the image light propagating in each of the light guide plates 220A to 220C can be made narrower, the configuration of each light guide plate 220 is optimized for the wavelength of the propagating light, so that the optical utilization efficiency and the like can be improved. Characteristics can be improved.

<Second Modification of Image Display Device 101>
Next, a second modification of the video display device 101, which is a first configuration example of the video display device 11, will be described. As shown in FIGS. 6 to 8, the video display apparatus 101 described above replicates and guides the video light from the video projection unit 200 in the one-dimensional direction (x-axis direction) by the video light replication unit 210. Although the light is incident on the light plate 220, the image light may be deformed so that the image light is duplicated in the two-dimensional direction (the x-axis direction and the y-axis direction) by the image light duplication unit 210 and then incident on the light guide plate 220.

17A and 17B show a second modification of the video display device 101. FIG. 17A is a sectional view of the xy plane of the second modification, and FIG. It is sectional drawing of the yz plane of the modification of 2.

映像 The image light duplicating unit 210 in the second modified example includes image light duplicating prisms 301A and 301B. The image light duplicating prism 301A duplicates the image light from the image projection unit 200 in the x-axis direction and outputs the duplicated image light to the image light duplicating prism 301B. The image light duplicating prism 301B duplicates the image light from the image light duplicating prism 301A in the z-axis direction and enters the light guide plate 220 from the light input unit 221.

Therefore, in the second modified example, the image light from the image projection unit 200 can be duplicated in the two-dimensional direction by the image light duplication unit 210 before being incident on the light guide plate 220. Thereby, the gap between the image lights emitted from the light guide plate 220 can be further reduced, and the image visually recognized by the user can be made more uniform.

In the second modified example shown in FIG. 17, the video light duplicating unit 210 is composed of two video light duplicating prisms 301A and 301B. The image light duplication diffraction element 311 (FIG. 7) or two image light duplication beam splitters 321 (FIG. 8) may be used.

<Modification of the video display device 102>
Next, a modified example of the video display device 102 which is the second configuration example of the video display device 11 will be described. In the above-described image display device 102, as shown in FIGS. 10 to 13, the image light from the image projection unit 200 is made to enter one light guide plate 400. The image light may be made incident on the plurality of light guide plates 400.

FIG. 18 shows a modification of the video display device 102. In this modification, three light guide plates 400A, 400B, and 400C are provided so as to overlap in the y-axis direction.

(4) The light input unit 221A of the light guide plate 400A captures at least a part of the image light from the image projection unit 200 into the light guide plate 400A and transmits at least a part thereof. The light input unit 221B of the light guide plate 400B captures at least a part of the image light transmitted through the light input unit 221A into the light guide plate 400B and transmits at least a part thereof. The light input unit 221C of the light guide plate 400C takes at least a part of the image light transmitted through the light input unit 221B into the light guide plate 400C.

(4) The light guide plates 400A to 400C have characteristics of transmitting light of different wavelengths. For example, the light guide plate 400A has a property to propagate light in the blue band, the light guide plate 400B has a property to propagate light in the green band, and the light guide plate 400C has a property to propagate light in the red band. To have.

This makes it possible for the image light to propagate through any of the light guide plates 400A to 400C according to the color of the image light. Furthermore, since the wavelength of the image light propagating in each of the light guide plates 400A to 400C can be narrowed, the configuration of each light guide plate 400 is optimized for the wavelength of the propagating light, so that optical efficiency such as light use efficiency can be improved. Characteristics can be improved.

The effects described in this specification are merely examples and are not limited. Other effects may be provided.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, each of the above embodiments has been described in detail in order to explain the present invention in an easily understandable manner, and the present invention is not necessarily limited to a configuration including all the described components. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. Further, for a part of the configuration of each embodiment, it is possible to add, delete, or replace another configuration.

DESCRIPTION OF SYMBOLS 10 ... Video display system, 11 ... Video display device, 12 ... Control device, 13 ... Video signal processing device, 14 ... Power supply device, 15 ... Storage device, 16 ... Sensing device, 17 sensor input / output unit, 18 communication device, 19 communication input / output unit, 20 voice processing device, 21 voice input / output unit, 101 to 104 .. An image display device, 120 ... eyes, 200 ... an image projection unit, 201 ... a fiber scanning projector, 202 ... a mirror scanning projector, 210 ... an image light duplication unit, 220 ... Light guide plate 220 220 Light guide plate 221 Light input unit 222 Light output unit 223 Inner reflective surface 224 Inner reflective surface 230 Image light replication Part, 240 ... total reflection light guide part, 250 ... video Duplicating unit, 301: Image light duplicating prism, 302: Input surface, 303: Output surface, 304: Image light splitting surface, 311: Image light duplicating diffraction element, 312: Input Plane, 313 ... output plane, 314 ... diffraction area, 315 ... diffraction area, 315A ... diffraction area, 315B ... diffraction area, 321 ... video light duplication beam splitter, 322 ... -Input surface, 323-Output surface, 400-Light guide plate, 401-Transparent flat plate, 402-Transparent flat plate, 403-Laminated surface, 404-Laminated surface, 405- ..Total reflection surface, 406: Transparent flat plate, 407: Bonding surface, 410: Light guide plate, 420: Light guide plate, 421: Image light duplicating unit, 421: Transparent flat plate , 423: bonding surface 424: bonding surface 430: light guide plate, 431: transparent flat plate, 431: video light duplicating part, 432: transparent flat plate, 433: bonding surface, 440: light guide plate, 441: transparent Flat plate, 442: transparent flat plate, 443: bonding surface, 700: light guide plate, 801: light guide plate, 802: diffraction region, 803: diffraction region, 804: diffraction Area, 811: Light guide plate, 812: Diffraction area, 813: Diffraction area, 821: Light guide plate, 822: Incident surface, 823: Partially reflective surface, 824: Light Output surface, 900: light source unit, 901: fiber, 902: fiber scanning element, 903: collimating lens, 904: end face, 911: scanning element

Claims (15)

1. An image projection unit that scans light to generate image light having a predetermined angle of view,
   A light guide plate that propagates the image light incident from the light input unit inside and outputs the light from the light output unit,
   An image light duplicating unit that duplicates the light beam of the image light,
   With
   The image display device, wherein the image light duplication unit duplicates two or more image lights having substantially the same angle of view as the incident image light.
2. The video display device according to claim 1,
   The image light duplicating section outputs the two or more image lights obtained by duplicating the image light from the image projecting section to the light guide plate,
   The image display device, wherein the light guide plate outputs the image light, which is output from the image light replication unit, enters the image light from the light input unit, and outputs the image light from the light output unit.
3. The video display device according to claim 2,
   The image light replication unit,
   An input surface on which the image light from the image projection unit is incident,
   Reflecting the incident image light, or a plurality of parallel image light branch surfaces that reflect a part of the image light and transmit the rest,
   An image display device comprising an image light duplicating prism having:
4. The video display device according to claim 3, wherein
   The video display device, wherein the reflectance of the plurality of image light branching surfaces is lower as being closer to the input surface except for the image light branching surface closest to the input surface.
5. The video display device according to claim 3, wherein
   The image light duplicating unit may be configured such that the arrangement interval Dist of the plurality of image light branch surfaces is substantially equal to or smaller than the opening size φPJ of the image light from the image projecting unit. Characteristic video display device.
6. The video display device according to claim 2,
   The image light replication unit,
   An input surface including a diffraction region that diffracts the image light incident from the image projection unit,
   An output surface including a plurality of diffraction regions that diffract the image light diffracted by the diffraction region of the input surface,
   Consisting of an image light duplicating diffraction element having
   The image display device, wherein directions and periods of diffraction structures of the diffraction area on the input surface and the diffraction area on the output surface are substantially the same.
7. The video display device according to claim 2,
   The image display device, wherein the image light duplication unit comprises an image light duplication beam splitter.
8. The video display device according to claim 1,
   The image light duplicating section duplicates the image light incident from the light input section of the light guide plate into the two or more image lights,
   The image display device, wherein the light guide plate propagates the two or more image lights duplicated by the image light duplication unit inside and outputs the light from the light output unit.
9. The video display device according to claim 8,
   The image light duplication unit is formed by stacking at least two or more transparent flat plates,
   An image display device, wherein a boundary surface between the two or more transparent flat plates reflects a part of the image light and transmits the rest.
10. The video display device according to claim 9,
    The image display device, wherein the two or more transparent flat plates forming the image light duplicating section have different thicknesses.
11. The video display device according to claim 1,
    The video display device, wherein the video projection unit is a fiber scanning projector.
12. The video display device according to claim 1,
    The image display device, wherein the image projection unit includes a mirror scanning type projector.
13. The video display device according to claim 1,
    The light guide plate has a plurality of diffraction regions,
    The image display device, wherein the light input unit and the light output unit are each one of the plurality of diffraction regions.
14. The video display device according to claim 1,
    The light guide plate includes:
    An incident surface corresponding to the light input unit,
    A plurality of partially reflecting surfaces arranged substantially in parallel,
    The image display device, wherein each of the plurality of partial reflection surfaces reflects at least a part of the image light incident from the incident surface and transmits the rest.
15. A video signal processing device for generating a video signal,
    A video display device that displays a video based on the video signal,
    With
    The image display device,
    An image projection unit that scans light based on the image signal to generate image light of a predetermined angle of view,
    A light guide plate that propagates the image light incident from the light input unit inside and outputs the light from the light output unit,
    An image light duplicating unit that duplicates the light beam of the image light,
    With
    The image display system, wherein the image light duplicating unit duplicates two or more image lights having substantially the same angle of view as the incident image light.

Images