JPWO2019171450A1 - Image display device - Google Patents

Abstract

The image light generated by the light source unit and the display element is introduced into the light guide (10) through the collimating optical system. The image light is reflected by the incident side reflecting surface (101) inside the substrate (100) of the light guide (10), and is totally reflected between the first surface and the second surface having a narrow interval, and is a beam splitter. It reaches the side reflecting surface (102a to 102e). A part of the image light reflected by the incident side reflecting surface (101) corresponds to the third surface and the fourth surface (100e, 100f), and both the third surface and the fourth surface (100e, 100f) are non-reflective surfaces. It is said that. Therefore, the light reflected on the third and fourth surfaces (100e, 100f) hardly reaches the emission side reflecting surfaces (102a to 102e). The image light reflected by each of the plurality of emission side reflecting surfaces (102a to 102e) forms a virtual image in front of the observer's eye E, but is due to the reflected light on the third and fourth surfaces (100e, 100f). High visibility can be achieved because ghosts that are flipped left and right do not overlap.

Description

The present invention relates to an image display device that displays image information as a virtual image in front of the user's eyes, and more particularly to an image display device that uses a light guide that enlarges a luminous flux (exit pupil). The image display device according to the present invention is suitable for image display devices such as helmet-mounted displays, head-up displays, and eyeglass-type displays (so-called smart glasses).

In automobiles and trains, a head that forms a virtual image display image in front of the driver by projecting an image displayed on a display element such as a liquid crystal display (LCD) onto a windshield or combiner and reflecting it toward the driver. Up display is used. Further, in an aircraft, a helmet mount display is used in which an image is projected onto a combiner provided on a helmet worn by the pilot on the head by a similar mechanism to form a virtual image display image in front of the pilot's eyes. .. Recently, eyeglass-type or head-mounted head-mounted displays called smart glasses have also begun to spread.

Various types of such image display devices are known as optical systems for displaying a virtual image in front of the observer's eyes, and one of them is a method using a light guide (light guide plate). As described in Patent Documents 1 and 2, Non-Patent Documents 1 and 2, etc., this is a substantially rectangular flat plate-shaped light flux having a small cross-sectional area including image information formed by an image forming portion and a collimating optical system. It is introduced into a certain light guide, and the luminous flux is enlarged and displayed by the light guide. In the following description, an image display device using such a light guide is simply referred to as an image display device.

4 and 5 are schematic views showing an optical path configuration in an example of a conventional image display device, FIG. 4 is a view of an observer observing the displayed image from the side, and FIG. 5 is a view. It is a figure of the state which the light guide 20 in 4 is seen from the front. For convenience of explanation, the x, y, and z axes that are orthogonal to each other are defined as shown in the figure.

The image display device 2 includes a light source unit 21, a display element 22, a collimating optical system 23, and a light guide 20. Here, the display element 22 is a transmissive liquid crystal display element, and the light source unit 21 is a backlight light source for a so-called transmissive liquid crystal display element. The light emitted from the light source unit 21 illuminates the display element 22 from the back side, and the light containing the image formed on the display surface of the display element 22 as information (hereinafter referred to as "image light") is emitted from the display element 22. Will be done. The collimating optical system 23 introduces the image light emitted from each point (pixel) on the display surface of the display element 22 into the light guide 20 as a substantially parallel luminous flux. Therefore, the light introduced from the collimating optical system 23 into the light guide 20 includes information on different parts of the image formed on the display surface of the display element 22, and parallel light flux incident on the light guide 20 at different angles. Is a set of.

The light guide 20 is a transparent substrate 200 having a flat cubic shape having a first surface 200a and a second surface 200b parallel to the yz plane, and a third surface 200c and a fourth surface 200d parallel to the xy plane. Be prepared. One incident-side reflecting surface 201 and a plurality of (three in this example) injection-side reflecting surfaces 202a to 202c are formed inside the substrate 200. The incident side reflecting surface 201 is perpendicular to the third and fourth surfaces and is inclined with respect to the first surface 200a and the second surface 200b. The plurality of ejection side reflecting surfaces 202a to 202e are also perpendicular to the third and fourth surfaces, inclined with respect to the first surface 200a and the second surface 200b, and they are parallel to each other. Further, the incident side reflecting surface 201 is a reflecting surface such as a mirror, and the emitting side reflecting surfaces 202a to 202c are partial reflecting surfaces having a predetermined reflectance (that is, transmittance), that is, a peep splitter or a half mirror.

As described above, the image light introduced from the collimating optical system 23 to the light guide 20 is reflected by the incident side reflecting surface 201 and then totally reflected by the second surface 200b and the first surface 200a one or more times while being totally reflected on the substrate. It propagates inside the 200 and reaches the reflection surface 202a on the injection side. The emission side reflecting surface 202a reflects a part of the reached image light and transmits the rest. The transmitted image light reaches the next emission side reflecting surface 202b, a part of the light is reflected, and the rest is transmitted. The same applies to the injection side reflecting surfaces 202c to 202e. Therefore, the image light propagating inside the substrate 200 of the light guide 20 is reflected by the plurality of emission-side reflecting surfaces 202a to 202c, and is transmitted to the outside through the first surface 200a of the substrate 200. The image light reflected by the reflecting surfaces 202a to 202e on the emission side is incident on the observer's eye E at a predetermined angle.

As described above, the image light including information on different parts of the image formed on the surface surface of the display element 22 is incident on the light guide 20 as a parallel light flux at different angles and is reflected by the incident side reflecting surface 201. In the process in which this luminous flux propagates inside the substrate 200 while being totally reflected by the first surface 200a and the second surface 200b, is partially reflected by the plurality of ejection side reflecting surfaces 202a to 202e, and is emitted from the substrate 200. , The luminous flux, that is, the exit pupil, is enlarged. In this way, in the image display device 2, the image formed on the display surface of the display element 22 is displayed as a virtual image in front of the observer's eyes. Further, since the substrate 200 of the light guide 20 is transparent and the ejection side reflecting surfaces 202a to 202e are partially reflecting surfaces, the observer can visually recognize the scenery in front through the light guide 20.

A see-through type image display device using such a light guide has a feature of being compact and lightweight. However, the conventional image display device has the following problems.
That is, among the image lights introduced from the collimating optical system 23 into the light guide 20, the luminous flux derived from the light emitted from the vicinity of the center of the display surface of the display element 22 is shown by a two-dot chain line in FIG. After being reflected by the incident side reflecting surface 101, it propagates substantially along the y-axis in the yz plane. On the other hand, among the image lights introduced from the collimating optical system 23 into the light guide 20, the luminous flux derived from the light emitted from a position near the end in the left-right direction (z-axis direction) on the display surface of the display element 22 is As shown by the alternate long and short dash line in FIG. 5, after being reflected by the incident side reflecting surface 101, the light propagates in the yz plane at a predetermined angle with respect to the y axis (that is, diagonally upward). In the light guide 20, the distance between the third surface 200c and the fourth surface 200d is larger than the distance between the first surface 200a and the second surface 200b. Therefore, the image light propagating at a predetermined angle with respect to the y-axis in the y-z plane does not easily reach the third surface 200c or the fourth surface 200d, but the third surface 200c on the incident side reflecting surface 201 A part of the image light reflected at a position relatively close to the fourth surface 200d hits the third surface 200c or the fourth surface 200d and is reflected. In this way, the image light reflected by the third surface 200c and the fourth surface 200d and the image light that is not reflected are reflected by the emission side reflecting surfaces 202a to 202e, respectively, and reach the observer's eye E.

In FIG. 5, the images obtained at the three positions I, II, and III on the light guide 20 are schematically shown at the upper part of the light guide 20. The numbers 1, 2 and 3 in this image indicate the positions on the image formed on the display surface of the display element 22, respectively, 2 is the center of the image, and 1 and 3 are near the left and right edges of the image, respectively. Indicates the position. Further, [1], [2], and [3] in FIG. 5 indicate the traveling direction of the luminous flux of the image light emitted from 1, 2, and 3 on the image formed on the display surface of the display element 22, respectively. Shown. For example, the image light obtained at the position II on the light guide 20 is incident on the luminous flux [2] emitted from the vicinity of the center of the display surface of the display element 22 which is reflected and arrives at the position ii on the reflecting surface 201 on the incident side. The luminous flux [1] emitted from the end of the display surface of the display element 22 reflected and arriving at the position i on the side reflecting surface 201 and the display element 22 reflected and arriving at the position iii on the incident side reflecting surface 201. Includes the luminous flux [3] emitted from the edge of the display surface of.

On the other hand, for example, the image light obtained at the position I on the light guide 20 is the luminous flux [2] emitted from the vicinity of the center of the display surface of the display element 22 which is reflected and arrives at the position i on the incident side reflecting surface 201. , The luminous flux [3] emitted from the end of the display surface of the display element 22 that is reflected at the position ii on the incident side reflecting surface 201 and the fourth surface 200d that is reflected at the position i on the incident side reflecting surface 201. It includes a luminous flux [3] emitted from an end portion of the display surface of the display element 22 which is further reflected and arrives. Since the image light reflected and arriving at the fourth surface 200d is reflected only once, it includes image information in which the left and right sides are reversed (specular reflection state). Therefore, the image light reflected once is superimposed as an image in which the original image is horizontally inverted. Similarly, the image obtained at the position III on the light guide 20 is a superposition of left-right inverted images that originate from the position [iii] and are reflected by the third surface 200c.

Ghosts with left-right reversal of the image, rather than the simple ghosts described above, in particular result in reduced visibility of the image. Images displayed by image display devices used by vehicle drivers and aircraft operators often contain important textual information that should be communicated while driving or maneuvering, but ghosts with left-right reversal of the image. May greatly reduce the visibility of characters.
In the above example, since the light guide 20 is arranged so as to extend in the vertical direction (y-axis direction), a ghost that is inverted left and right occurs, but the light guide is extended in the horizontal direction (z-axis direction). An upside-down ghost will occur in the arranged image display device.

Japanese Patent No. 5447714 Japanese Patent No. 5299391

Khaled Sarayeddine and 3 others, "Monolithic Low Cost plastic light guide for Full" Monolithic Low Cost plastic light guide for Full colour See-Through Personal Video Glasses) ”, [online], [Search on December 20, 2017], Internet <URL: http://optinvent.com/wp-content/uploads/2016/03/IDW2010_PRJ2_1.pdf ＞ Kayvan Mirza and one others, "Key Challenges to Affordable See-Through Wearable Display: The Missing Link for Mobile AR Deployment (Key Challenges to Affordable) See Through Wearable Displays: The Missing Link for Mobile AR Mass Deployment) ”, [online], [Search on December 20, 2017], Internet <URL: http://www.optinvent.com/wp-content/uploads /2016/04/Position-Paper-AR-Glasses-V2.pdf ＞

The present invention has been made to solve the above problems, and an object of the present invention is to reduce the occurrence of ghosts that are flipped horizontally or vertically, which leads to a large decrease in visibility. It is to provide an image display device.

The image display device according to the present invention made to solve the above problems is
a) An image forming unit that emits image light containing an image formed on the screen of the display element as information, and
b) An incident optical system that parallelizes the image light from the image forming unit and causes it to enter the light guide described later.
c) A transparent substrate having the first and second surfaces parallel to each other and the third and fourth surfaces facing each other with a separation distance longer than the separation distance between the first and second surfaces. An incident portion that guides the image light incident through the incident optical system into the inside of the substrate so that the image light is totally reflected by the first surface and the second surface, and is guided from the incident portion into the inside of the substrate. A light guide having an ejection portion that ejects image light that has propagated through the substrate while being totally reflected by the first surface and the second surface to the outside of the substrate at a predetermined position while expanding the light beam. ,
The light guide is characterized in that at least one of the third surface and the fourth surface is a non-reflective surface.

Here, "a part of at least one of the third surface and the fourth surface" is specifically at least a part of a portion where the image light guided to the inside of the substrate by the incident portion can reach.

In the present invention, the non-reflective surface is any surface as long as it has an effect of eliminating reflection at the interface between the substrate and its external world (typically, the outer atmosphere) or reducing the degree of reflection thereof. It may be.

For example, as one aspect of the present invention, the non-reflective surface may be a light-shielding surface. Specifically, for example, such a light-shielding surface can be formed by applying an antireflection agent to the surface of the substrate. Further, as another aspect of the present invention, the non-reflective surface may be a light scattering surface. Specifically, for example, such a light scattering surface can be a surface that has been subjected to a process of forming fine irregularities on the surface of the substrate, for example, a polished surface.

In the present invention, the image light that is parallelized through the incident optical system and introduced into the substrate of the light guide is totally reflected between the first surface and the second surface of the substrate by the incident portion of the light guide. It is guided inside the substrate. This image light propagates inside the substrate and reaches the injection portion while being totally reflected between the first surface and the second surface, which are narrower than the separation interval between the third surface and the fourth surface. .. Then, the image light is taken out from the substrate by the ejection portion, and a virtual image is formed in front of the observer's eyes. On the other hand, a part of the image light guided to the inside of the substrate by the incident portion hits the third surface and the fourth surface while facing the first surface and the second surface, respectively, but at least the part exposed to the image light is not on these surfaces. Since it is a reflective surface, the hit image light is not reflected. Therefore, the image light emitted to the outside of the substrate at the ejection portion, that is, the image light that contributes to the formation of the virtual image does not include the reflected light on the third surface and the fourth surface. As a result, for example, it is possible to reduce the phenomenon that the above-mentioned image is flipped horizontally or vertically, resulting in a ghost.

According to the image display device according to the present invention, it is possible to reduce the superimposition of ghosts flipped horizontally or vertically on a regular image and improve the visibility of a virtual image displayed by a light guide. ..

It is a schematic block diagram of the optical system in the image display apparatus which is one Example of this invention, and is the sectional view of the state which the observer observing the displayed image is seen from the side. It is the schematic block diagram of the optical system in the image display apparatus of this Example, and is the top view of the state which the light guide 10 in FIG. 1 is seen from the front. A plan view of the light guide 10 in the image display device of this embodiment as viewed from below. It is a schematic block diagram of an optical system in a conventional image display device, and is a cross-sectional view of an observer observing the displayed image as viewed from the side. It is the schematic block diagram of the optical system in the conventional image display apparatus, and is the top view of the state which the light guide 20 in FIG. 4 is seen from the front.

An image display device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
1 and 2 are schematic sectional views of an optical system in the image display device of the present embodiment, and similarly to FIGS. 4 and 5, FIG. 1 shows an observer observing the displayed image from the side. FIG. 2 is a cross-sectional view of the light guide 10 in the state of being viewed from the front. Further, FIG. 3 is a plan view of the light guide 10 in FIG. 1 as viewed from below.

The image display device 1 of this embodiment includes a light source unit 11, a display element 12, a collimating optical system 13, and a light guide 10 as in the conventional image display device 2 shown in FIGS. 4 and 5. As the light source unit 11, the display element 12, and the collimating optical system 13, the same light source unit 21, the display element 22, and the collimating optical system 23 in the conventional image display device 2 can be used, but the method is not limited thereto. For example, as the display element 12, instead of the transmissive liquid crystal display element, a reflective liquid crystal display element, an organic EL display, a DMD (Digital Macromirror Device), a MEMS mirror, or the like can be used.

When a reflective liquid crystal display element or DMD is used as the display element 12, the light source unit 11 uses one that illuminates the liquid crystal display element or DMD from the front side. When a self-luminous display element such as an organic EL display is used as the display element 12, it can be considered that the light source unit 11 is built in the display element 12. When a MEMS mirror whose angle is scanned is used as the display element 12, a laser light source that irradiates a thin laser beam toward the MEMS mirror may be used as the light source unit 11.

Like the light guide 20 in the conventional image display device 2, the light guide 10 has a first surface 100a and a second surface 100b parallel to the yz plane, and a third surface 100e and a third surface parallel to the xy plane. A substrate 100 having a flat cubic shape having four sides 100f is provided. The substrate 100 is a transparent material such as polycarbonate resin or quartz glass. Inside the substrate 100, one incident-side reflecting surface 101 corresponding to the incident portion in the present invention and a plurality of (five in this example) injection-side reflecting surfaces 102a to 102e corresponding to the injection portion in the present invention are formed. It is formed. The incident side reflecting surface 101 is perpendicular to the third surface 100e and the fourth surface 100f, and is inclined (non-parallel) with respect to the first surface 100a and the second surface 100b. The plurality of ejection side reflecting surfaces 102a to 102e are also perpendicular to the third surface 100e and the fourth surface 100f, inclined with respect to the first surface 100a and the second surface 100b, and they are parallel to each other. .. The incident side reflecting surface 101 is a total reflecting surface, and the emitting side reflecting surfaces 102a to 102c are partial reflecting surfaces having a predetermined reflectance.

The light guide 10 differs from the light guide 20 in the conventional image display device 2 in that the third surface 100e and the fourth surface 100f have a considerably larger distance than the distance between the first surface 100a and the second surface 100b. Are both non-reflective surfaces. Here, in order to make the third surface 100e and the fourth surface 100f non-reflective surfaces, a coating layer is formed on the surface (interface with the outside world) of the substrate 100 by applying an antireflection paint to a predetermined thickness. However, the method of using a non-reflective surface is not limited to this. For example, the surface of the substrate 100 may be polished to form fine irregularities so that the light that reaches the surface is scattered. Here, the "non-reflective surface" may be a surface whose reflectance is reduced to such an extent that it can be regarded as having substantially no reflection even if it does not have complete non-reflective properties.

In the image display device 1 of the present embodiment, the image light emitted from the display screen of the display element 12 in response to the illumination light from the light source unit 11 is substantially parallelized by the collimating optical system 13 and passed through the second surface 100b. Introduced in the light guide 10. Similar to the conventional image display device, the image light introduced from the collimating optical system 13 into the light guide 10 includes information on different parts of the two-dimensional image formed on the display surface of the display element 12. , A set of parallel light beams incident on the light guide 10 at different angles.

After being reflected by the incident side reflecting surface 101, this image light propagates inside the substrate 100 while being totally reflected once or multiple times by the second surface 100b and the first surface 100a, and the emission side reflecting surface located at the bottom. It reaches 102a. At this time, among the image lights introduced into the light guide 10, the luminous flux derived from the light emitted from the vicinity of the center of the display surface of the display element 12 is reflected by the incident side reflection surface 101 and then the yz surface. Within, it propagates almost along the y-axis. On the other hand, among the image lights introduced into the light guide 10, the luminous flux derived from the light emitted from the position near the end in the left-right direction (z-axis direction) on the display surface of the display element 12 is the reflecting surface on the incident side. After being reflected by 101, it propagates in the yz plane at a predetermined angle with respect to the y-axis (that is, diagonally upward). Therefore, a part of such image light hits the third surface 100e or the fourth surface 100f, and these surfaces are non-reflective surfaces. Therefore, the image light reaching the third surface 100e and the fourth surface 100f disappears without being reflected (strictly speaking, it is absorbed or scattered). Therefore, the image light that hits the third surface 100e or the fourth surface 100f even once does not reach the subsequent emission side reflecting surfaces 102a to 100e.

The emission side reflecting surface 102a reflects a part of the reached light flux and transmits the rest. The transmitted light reaches the next emission side reflecting surface 102b, a part of the light flux is reflected, and the rest is transmitted. The same applies to the injection side reflecting surfaces 102c to 102e. Therefore, the light flux propagating inside the substrate 100 of the light guide 10 is reflected by the plurality of ejection side reflecting surfaces 102a to 102e, and is transmitted to the outside through the first surface 100a of the substrate 100. As described above, the reflected light from the third surface 100e and the fourth surface 100f of the substrate 100 hardly reaches the emission side reflection surfaces 102a to 102e, so that the light is reflected by the emission side reflection surfaces 102a to 102e and passes through the first surface 100a. The image light emitted to the outside of the light guide 10 contains almost no reflected light from the third surface 100e and the fourth surface 100f.

For example, in FIG. 2, the image light obtained at the position I on the light guide 10 is a luminous flux [2] emitted from the vicinity of the center of the display surface of the display element 12 which is reflected and arrives at the position i on the incident side reflecting surface 101. ] And the luminous flux [3] emitted from the end of the display surface of the display element 12 that is reflected and arrives at the position ii on the incident side reflecting surface 101, but unlike the conventional image display device, it is incident. The luminous flux [3] emitted from the end of the display surface of the display element 12 that is reflected at the position i on the side reflecting surface 101 and further reflected at the fourth surface 100f is not included. Therefore, an image whose left and right sides are inverted by being reflected once is not superimposed. The same applies to the image light obtained at the position I on the light guide 10. Therefore, the left-right inverted ghost of the image is not superimposed on the virtual image seen from the observer's eye E. As described above, the image display device 1 of this embodiment can provide the observer with a highly visible image (virtual image).

The configuration of the light guide 10 in the image display device of the above embodiment, specifically, the configuration of the incident portion and the emitting portion in the present invention can be variously modified according to the configuration of the well-known light guide.
For example, as the incident portion that guides the image light inside the substrate 100 of the light guide 10, for example, as described in Non-Patent Document 1, a part of the first surface 100a of the substrate 100 of the light guide 10 is the first. By making the two surfaces 100b non-parallel, a reflective surface that reflects image light on the non-parallel surface (the interface between the substrate 100 and the outside world) may be used. Alternatively, as the incident portion, a reflective volume hologram grating as described in Non-Patent Document 2 or Patent Document 2 may be used.
Further, a reflective volume hologram grating may be used as an injection portion for emitting image light from the inside of the substrate 100 of the light guide 10 to the outside.
Further, the third surface 100e and the fourth surface 100f of the substrate 100 do not have to be parallel to each other. Further, the third surface 100e and the fourth surface 100f do not have to be the non-reflective surface as a whole, and if the whole or a part of the range in which the image light can reach is a non-reflective surface. Although there is a difference, the above-mentioned effects can be obtained.

Further, it is natural that the patent claims of the present application include not only the above-mentioned examples and the above-mentioned modifications, but also changes, modifications, and additions as appropriate within the scope of the present invention.

1 ... Image display device 10 ... Light guide 100 ... Substrate 100a ... First surface 100b ... Second surface 100e ... Third surface (non-reflective surface)
100f ... Fourth surface (non-reflective surface)
101 ... Incident side reflecting surface 102a-102e ... Ejecting side reflecting surface 11 ... Light source unit 12 ... Display element 13 ... Collimating optical system

The light guide 20 is a transparent substrate 200 having a flat cubic shape having a first surface 200a and a second surface 200b parallel to the yz plane, and a third surface 200c and a fourth surface 200d parallel to the xy plane. Be prepared. One incident-side reflecting surface 201 and a plurality of (three in this example) injection-side reflecting surfaces 202a to 202c are formed inside the substrate 200. The incident side reflecting surface 201 is perpendicular to the third and fourth surfaces and is inclined with respect to the first surface 200a and the second surface 200b. The plurality of ejection side reflecting surfaces 202a to 202e are also perpendicular to the third and fourth surfaces, inclined with respect to the first surface 200a and the second surface 200b, and they are parallel to each other. Further, the incident side reflecting surface 201 is a reflective surface such as a mirror, the exit-side reflecting surface 202a~202c predetermined reflectivity (that is, transmittance) partially reflecting plane or with is bi chromatography beam splitter or a half mirror.

The image display device according to the present invention made to solve the above problems is
a) An image forming unit that emits image light containing an image formed on the screen of the display element as information, and
b) An incident optical system that parallelizes the image light from the image forming unit and causes it to enter the light guide described later.
c) A transparent substrate having the first and second surfaces parallel to each other and the third and fourth surfaces facing each other with a separation distance longer than the separation distance between the first and second surfaces. An incident portion that guides the image light incident through the incident optical system into the inside of the substrate so that the image light is totally reflected by the first surface and the second surface, and is guided from the incident portion into the inside of the substrate. A light guide having an ejection portion that ejects image light that has propagated through the substrate while being totally reflected by the first surface and the second surface to the outside of the substrate at a predetermined position while expanding the light beam. ,
The present invention is characterized in that at least one of the third surface and the fourth surface of the light guide is a non-reflective surface with respect to the image light propagating in the substrate of the light guide . ..
It is a partially reflective surface having.

Claims (6)

a) An image forming unit that emits image light containing an image formed on the screen of the display element as information, and
b) An incident optical system that parallelizes the image light from the image forming unit and causes it to enter the light guide described later.
c) A transparent substrate having first and second surfaces parallel to each other and third and fourth surfaces facing each other with a separation distance longer than the separation distance between the first and second surfaces. An incident portion that guides the image light incident through the incident optical system into the inside of the substrate so that the image light is totally reflected by the first surface and the second surface, and is guided from the incident portion into the inside of the substrate. A light guide having an ejection portion that ejects image light that has propagated through the substrate while being totally reflected by the first surface and the second surface to the outside of the substrate at a predetermined position while expanding the light beam. ,
An image display device comprising the above, wherein at least one part of the third surface and the fourth surface of the light guide is a non-reflective surface. The image display device according to claim 1.
An image display device characterized in that the non-reflective surface is a light-shielding surface. The image display device according to claim 2.
An image display device characterized in that the light-shielding surface is formed by applying an antireflection agent. The image display device according to claim 1.
An image display device characterized in that the non-reflective surface is a light scattering surface. The image display device according to claim 4.
An image display device characterized in that the light scattering surface is a surface that has been processed to form fine irregularities on the surface of the substrate. The image display device according to any one of claims 1 to 5.
The incident portion is a reflective surface formed inside the substrate and is non-parallel to the first surface and the second surface.
An image display device characterized in that the injection portion is a plurality of partially reflecting surfaces formed inside the substrate and which are non-parallel to the first surface and the second surface.

Images