JP2017142406A - Virtual image optical system and virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image optical system comprising a light guide that avoids dust from adhering to/accumulating on an acute angle part, prevents the acute angle part itself from being chipped, and prevents a user from being injured.SOLUTION: A virtual image optical system comprises an image display element, a coupling optical system, and a light guide 50 that guides image information as light and emits the image information for displaying a virtual image. The light guide 50 includes a light guide member 100 and an optical member 200; the light guide member 100 includes a light beam incident part 101 on which the image information is made incident, an image extraction part 103 that extracts the image information to the outside, and a light beam emission part 104 that emits image light to the outside. The light guide 50 has transparent members 600a and 600b joined to its front face side and back face side with adhesion layers 601a and 601b made of an adhesive, and is coated with a continuous coating layer.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a virtual image optical system and a virtual image display device using a light guide.

A virtual image display device using a light guide is known as a device that enlarges a two-dimensional image using a virtual image optical system and displays an enlarged virtual image so that an observer (user) can observe it. As one form of light guide used in such a virtual image display device, a head mounted display (hereinafter referred to as “HMD”) has recently become widespread. The HMD is classified into a see-through transmission type and a non-transmission type. The transmission type HMD is, for example, Google LTD. (United States) Googleglass (registered trademark). Various proposals have also been made by non-transparent HMDs for their immersion.
Since the transmissive HMD is used in combination with an information terminal or used for providing AR (Augmented Reality) or the like, it is desired to be small and have good portability. The non-transparent HMD is desired to have a wide viewing angle that provides an immersive feeling because it is used for watching movies, providing games, and providing VR (Virtual Reality).
With regard to the outer shape and size of the HMD, the viewing angle tends to be narrower if emphasis is placed on reducing the size and thickness of the main body. Conversely, when the display area is wide, the main body size increases and becomes thicker. There is a tendency.

In recent years, the transmission type has been required to be thin, downsized, and have a wide viewing angle due to user needs.
For example, a virtual image display device described in Patent Document 1 (Japanese Patent No. 4508655) is known as a device that meets the demand for such a transmissive virtual image display device.
In the virtual image display device of Patent Document 1, the light incident portion and the light emitting portion of the light guide plate are positioned on the same plane, and the principal light of the projection lens of the coupling optical system (or collimator optical system) is directed to the light guide plate. One or more optical means arranged on the substrate, arranged to be perpendicularly incident and having two or more principal surfaces and edges in the light-transmitting substrate and imaging light on the substrate by total reflection; It consists of a partially reflective surface.
In this Patent Document 1, light (image information) incident on a light guide plate is reflected a plurality of times inside a flat substrate, and then is emitted outside the substrate by an array of selective reflecting surfaces. It is configured to be reflected in.

  The virtual image display device configured as described in Patent Document 1 can effectively extract an image. However, the light transmission substrate of the virtual image display device is composed of a plurality of prisms, and the prisms have acute corners (hereinafter referred to as “acute corners” or “edges”) on the outermost surface. Exists. Since the acute angle portion is located on the outermost surface of the light transmissive substrate, in the HMD having such a light transmissive substrate, dust or the like is attached / deposited at or near the acute angle portion, which is viewed by the user. Therefore, see-through property is impaired. Further, when the acute angle portion further protrudes from the surface of the adjacent component, there is a problem that the acute angle portion itself may be lost or a user who touches the acute angle portion may be injured.

  The present invention has been made in view of the above circumstances, and prevents an acute angle portion from being formed on the outermost surface thereof, thereby avoiding the adhesion / deposition of dust on the acute angle portion, and the sharp angle portion itself being lost. It is an object of the present invention to provide a virtual image optical system including a light-transmitting substrate (light guide) that prevents the user from being injured.

The virtual image optical system according to the present invention is:
An image display element for displaying image information which is a virtual image, a coupling optical system for coupling image information of the image display element, and the image information coupled by the coupling optical system are guided. A virtual image optical system comprising a light guide for emission,
The light guide has a light guide member and an optical member,
The light guide member is
A light incident part for making the image information incident on the inside thereof;
An image extraction unit for extracting the image information to the outside;
A light emitting part for emitting the image information to the outside,
The optical member is
The light guide member has a surface disposed in proximity to the image extraction unit and disposed in parallel to face the light emitting unit,
At least one outermost surface of the light guide is covered with a single continuous covering layer.

  According to the present invention, an acute angle portion is not formed on the outermost surface, thereby preventing dust from adhering / depositing on the acute angle portion, preventing the acute angle portion itself from being lost, and injuring the user. It is possible to provide a virtual image optical system provided with a light guide that does not have any.

It is a XZ plane schematic diagram showing roughly an embodiment of a virtual image optical system to which the present invention is applied, and shows a positional relationship of an image display element, a coupling optical system, and a light guide. It is a perspective view which shows the external appearance structure of the virtual image optical system of FIG. FIG. 2 is an optical path diagram of the virtual image optical system in FIG. 1. FIG. 3 is an XZ plan view showing the light guide of FIG. 1. FIG. 5 is an exploded view of the light guide of FIG. 4 before assembly. FIGS. 4A and 4B are XZ plan views showing a comparison of light guides, where FIG. 3A shows the light guide of FIG. 3 and FIG. It is a fragmentary sectional view which expands and shows the image extraction part of the light guide member of FIG. FIG. 8 is a partially enlarged XZ plan view showing a light guide member and an optical member in FIG. 7, and an enlarged view of an image extraction unit. It is sectional drawing which shows Embodiment 1 of the virtual image optical system of this invention. FIG. 10 is an exploded perspective view of the virtual image optical system in FIG. 9. FIG. 10 is an assembly diagram of the virtual image optical system of FIG. 9. It is a perspective view which shows the modification provided with the reinforcement member in the virtual image optical system of FIG. It is XZ top view which shows the light guide of FIG. It is a XZ top view which shows Embodiment 2 of the virtual image optical system of this invention. It is a disassembled perspective view of the virtual image optical system of FIG. It is a perspective view which shows the assembly state of the virtual image optical system of FIG. FIG. 13 is an XY plan view of the virtual image optical system in FIG. 12. FIG. 13 is an XZ plan view of Modification 1 of Embodiment 2 when a spacing member is removed from the virtual image optical system of FIG. 12. FIG. 16 is an XZ plan view showing the light guide of FIG. 15. It is a figure which shows Embodiment 3 of the virtual image optical system of this invention. FIG. 18 is an XZ plan view of the virtual image optical system in FIG. 17. FIG. 18 is an XY plan view of the virtual image optical system in FIG. 17. FIG. 18 is an assembly diagram of the virtual image optical system of FIG. 17. FIG. 18 is an XZ plan view of Modification 1 when the light guide of FIG. 11 is used in the virtual image optical system of FIG. 17. It is XZ sectional drawing of the modification 1 of the virtual image optical system of FIG. FIG. 20 is an XY plan view of Modification 1 of the virtual image optical system in FIG. 19. FIG. 20 is an assembly diagram of Modification 1 of the virtual image optical system in FIG. 19. It is a XZ top view which shows the structure of Embodiment 4 of the virtual image optical system of this invention. It is a XZ top view which decomposes | disassembles and shows the structure of each member of the virtual image optical system of FIG. 21A. FIG. 21B is an exploded perspective view of the virtual image optical system in FIG. 21A. It is a perspective view which shows the structure of the modification provided with the reinforcement member in the virtual image optical system of FIG. 21A. It is a disassembled perspective view which shows the structure of the modification 1 which provided the air gap in the virtual image optical system of FIG. 21A. It is a disassembled perspective view which shows the structure of the modification 2 which provided the air gap in the image extraction part side in the virtual image optical system of FIG. 21A. FIG. 21B is an exploded perspective view showing a configuration of Modification 3 of Embodiment 4 in which an air gap is provided on both the extending portion side and the image extracting portion side in the virtual image optical system of FIG. 21A. It is a disassembled perspective view which shows the structure of the modification 4 which provided the air gap in the extending | stretching part side between the transparent member and light guide member of the rear surface side of a light guide in the virtual image optical system of FIG. 21A. It is a disassembled perspective view which shows the structure of the modification 5 which used the combination of the modification 3 and the modification 4 in the virtual image optical system of FIG. 21A. It is a disassembled perspective view which shows the structure of the modification 6 which provided the air gap of the modification 1 in the virtual image optical system of FIG. FIG. 21B is an exploded perspective view showing a configuration of Modification Example 7 in which an air gap is provided between the transparent member on the rear surface side of the light guide and the light guide member in addition to the air gap of Modification Example 3 in the virtual image optical system of FIG. 21A. It is a XZ top view which shows the structure of Embodiment 5 of the virtual image optical system of this invention. FIG. 30B is an XZ plan view showing a correspondence relationship among members of the virtual image optical system in FIG. 30A. FIG. 30B is an exploded perspective view of the virtual image optical system in FIG. 30A. FIG. 30B is an XZ plan view showing a modification in which the light guide member of the virtual image optical system in FIG. 30A is provided with an extending portion. It is a XZ top view which shows the structure of Embodiment 6 provided with the transmittance | permeability variable means of the virtual image optical system of this invention. It is XZ top view which shows the structure of Embodiment 7 provided with the space | interval holding member of the virtual image optical system of this invention. It is a XZ top view which shows the structure of Embodiment 8 of the virtual image optical system of this invention. It is a top view which shows the use condition of the virtual image display apparatus provided with the virtual image optical system of this invention. It is a schematic diagram showing the example which applied the virtual image optical system of this invention to spectacles type HMD, (a) is a case where a light guide is made into a binocular integrated type, (b) And (c) is a monocular for a light guide. The figure shows the case of applying to the left and right eyes and the case of applying to one eye.

Hereinafter, virtual image optical systems and virtual image display devices according to Embodiments 1 to 8 and modifications thereof to which the present invention is applied will be described with reference to FIGS.
As shown in FIGS. 1 to 6 and 9, the basic feature is that image information incident on the light guide 50 from the coupling optical system (or collimating optical system) 300 is generated inside the light guide member 100. After being totally reflected a plurality of times, the surface of the light guide 50 is exposed to the transparent member when it is emitted to the outside of the light guide 50 by the action of the image extracting unit 103 which is a selective reflection surface and the image information is provided to the user's eyes. And a single continuous surface (see FIG. 9). By doing so, it is possible to prevent an acute angle portion from being formed on the outermost surface, and to prevent dust from adhering / depositing on the acute angle portion.
The embodiment described below relates to a virtual image optical system and a virtual image display device using a transmissive light guide. First, the configuration of a virtual image optical system for a virtual image display device will be described.

(Embodiment 1)
A virtual image optical system that is a basic configuration of the present embodiment shown in FIGS. 1 and 2 includes an image display element 10 that outputs image information of a display image, and a cup that couples and emits image information from the image display element 10. A ring optical system 300 and a light guide 50 are provided. The light guide 50 guides the image information that is enlarged and emitted from the coupling optical system 300 to the inside and emits it toward the outside, that is, the eyes of the observer (user) for virtual image display. It is. FIG. 3 shows the optical path of such a virtual image optical system with an arrow. Hereinafter, the light guide 50 will be described with the front side (lower side in FIG. 3) as viewed from the observer (user) as the “rear surface” and the rear side (upper side in FIG. 3) as the “front surface”.
The image display element 10 is a device that outputs image information of a display image that is a basis of a virtual image displayed through the light guide 50. The image display element 10 is preferably an organic LED (OLED: Organic Light Emitting Diode) or a liquid crystal display element, but various other display methods can be applied. For example, a DMD (Digital Micromirror Device) can be applied as the image display element 10.

Further, as the image display element 10, TFT (Thin Film Transistor) or LCOS (Liquid Crystal On Silicon) can be applied. Further, as the image display element 10, MEMS (Micro Electro Mechanical Systems) can be applied.
The coupling optical system 300 enlarges the above-described image information output from the image display element 10 and emits it as parallel light. As shown in FIG. 3, the coupling optical system 300 is arranged so that the central axis (optical axis) of the emitted light is inclined with respect to a light emitting unit 104 described later of the light guide 50. A configuration example of the coupling optical system 300 will be described later.

(Light guide)
The light guide member 100 constituting the light guide 50 guides the image information from the coupling optical system 300 to the inside and guides the image information to the outside, that is, toward the eyes of the observer (user). Information is provided as a virtual image to an observer (user). As shown in FIG. 4, the light guide 50 is integrated with the light guide member 100 for entering, guiding and emitting image information, and the light guide member 100 to ensure the see-through property of the light guide 50. The optical member 200 is provided.
FIG. 3 shows image information of the virtual image display device of the present invention by arrows. The light guide 50 includes a light beam incident unit 101 for allowing image information from the coupling optical system 300 to enter, and a light beam emission for causing the image information enlarged and incident into the light guide 50 to be emitted to the outside of the light guide 50. The light incident part 101 and the light emitting part 104 are configured from different surfaces.
As shown in FIG. 4, the light incident from the light incident unit 101 sequentially passes between the surface 105 (+ Z side surface), the image extraction unit 103, and the light emission unit 104 side surface (−Z side surface) 106. After being reflected (multiple times), the light exits from the light emitting unit 104 and reaches the eyes of the observer (user).

(Light guide member)
In the first embodiment, the light guide member 100 of the light guide 50 includes a light incident unit 101 on which image information from the coupling optical system 300 is incident, and a light emitting unit 104 that emits image information to the outside. . The light incident part 101 and the light emitting part 104 are formed on different surfaces. “Different planes” means that the planes are not the same plane or parallel planes, and the other side is inclined with respect to one side. In the first embodiment, the light incident part 101 is inclined at an obtuse angle with respect to the light emitting part 104.
In Embodiment 1 of the present invention, the light incident part 101 and the light emitting part 104 of the light guide member 100 are each flat. By making the light incident part 101 and the light emitting part 104 flat, the productivity of the light guide member 100 and the light guide 50 is improved, and the light guide member 100 and the entire light guide 50 are made simple. Can do.
Further, by making the light incident portion 101 and the light emitting portion 104 different surfaces, the angle of the incident light can be set to a more appropriate angle, thereby making the light guide 50 compact, that is, small. It becomes possible to make it thin. Also, by making the light incident part 101 and the light emitting part 104 different surfaces, a wide light bundle can be obtained, which is advantageous for making the viewing angle wide.

In addition, when the light incident part 101 and the light emission part 104 are made into the same surface, although the ease of a processing surface and a management surface exists, the freedom degree of the light incident part 101 and the light emission part 104 reduces. For this reason, if the viewing angle is widened, the light guide becomes larger and thicker. For this reason, in the embodiment of the present invention, the light incident part 101 and the light emitting part 104 are provided on different surfaces.
On the other hand, in order to improve the see-through property, the light guide member 100 has a rear surface on which the light emitting section 104 is provided and a front surface 105 on the back side (upper side in FIG. 4) formed in parallel to each other.
The light guide member 100 includes an image extraction unit 103 for guiding the image information incident from the light incident unit 101 to the light emission unit 104 and extracting the image information. A specific configuration of the image extraction unit 103 will be described later. The material of the light guide member 100 is preferably a highly permeable material in view of see-through properties, and is preferably molded from a resin in consideration of the processing of the image extraction unit 103 described later.

  The light guide of the present embodiment shown in FIG. 6 and a light guide having the light incident part 101 and the light emitting part 104 as the same surface as a reference example are shown in comparison with FIGS. 6 (a) and 6 (b), respectively. . As shown in FIGS. 6 (a) and 6 (b), the light incident from the coupling optical system 300 travels toward the light emitting section 104 while being totally reflected back and forth obliquely in the light guide. Here, the light guide in FIG. 6A in which the light incident portion 101 and the light emitting portion 104 are different surfaces is the same as that in FIG. 6B in which the light incident portion 101 and the light emitting portion 104 are the same surface. As compared with, the number of reflections can be reduced while shortening the length in the longitudinal direction. Thus, the light guide can be made small by making the light incident part 101 and the light emitting part 104 different surfaces.

(Optical member)
An outline of the light guide member 100 and the optical member 200 of the light guide 50 will be described with reference to FIGS. 4 and 5. The optical member 200 has an acute triangular prism shape in the XZ plane, and is inclined with respect to the front surface 210 and the front surface 210 that face the light emitting portion 104 of the light guide member 100 in parallel. It has a slope 214 arranged to face the surface 213 of the image extraction unit 103. The inclined surface 214 of the optical member 200 is a part that is installed close to or joined to the inclined surface 213 of the image extraction unit 103 of the light guide member 100, and details thereof will be described later.
The light guide 50 is disposed so that the front surface 105 of the light guide member 100 and the front surface 210 of the optical member 200 parallel to the light guide member 100 are flush with each other. The front and rear surfaces are kept parallel. As will be described later, as a modification of the light guide, the front surface 210 of the optical member 200 protrudes forward (upward in FIG. 4) from the position of the front surface 105 of the light guide member 100 or retracts backward. It is possible to do. That is, considering the see-through property, the surface positions of the front surface 105 of the light guide member 100 and the front surface 210 of the optical member 200 facing each other are preferably coincident with each other. It is good also as a form which shifts the surface position of both surfaces.

In the light guide 50, the plane (rear surface 106) of the light emitting portion 104 of the light guide member 100 and the corresponding rear surface 212 of the optical member 200 are parallel. With such a configuration, the see-through property through the light emitting portion 104 is improved. If the surface (rear surface 106) of the light emitting part 104 of the light guide member 100 and the corresponding rear surface 212 of the optical member 200 are not parallel, the see-through property is reduced by the prism effect, which is not preferable.
The optical member 200 will be described later.

(Image extraction part of light guide member)
Next, the configuration of the image extraction unit 103 of the light guide member 100 will be described with reference to partially enlarged cross-sectional views of FIGS. 7 and 8. FIG. 8 illustrates an enlarged part of each of the image extraction unit 103 and the light emitting unit 104 of the light guide member 100, and FIG. 7 illustrates an enlarged part of the image extraction unit 103.
As shown in FIG. 7, the image extraction unit 103 is configured by three planes and has a generally sawtooth shape.
Specifically, the image extraction unit 103 includes a first surface 103a having an angle θa with respect to a direction (Z axis) perpendicular to the light emitting unit 104, a second surface 103b parallel to the X axis, and light emission. The third surface 103c, which is an inclined surface having an angle θc with respect to the direction perpendicular to the portion 104 (Z axis), is continuously and periodically arranged.
First, the first surface 103a is a surface that reflects the image information incident on the light guide member 100 from the light incident unit 101, guides it to the light emitting unit 104, and emits it from the light emitting unit 104. The plane is inclined with respect to the portion 104. The angle θa at which the first surface 103a is inclined with respect to the light emitting portion 104 is preferably set in the range of 20 degrees to 30 degrees, although it depends on the refractive index of the material of the light guide member 100.

Moreover, it is preferable that the first surface 103a is subjected to a coating process that reflects the light incident on the light guide member 100 from the light incident part 101 and can ensure the see-through property of external light.
Next, the second surface 103b is a surface that plays a role as a reflecting surface for guiding incident image information into the light guide member 100, and is a plane parallel to the light emitting unit 104 (rear surface). Yes. Therefore, the angle θb = 0 °. Further, the second surface 103b also serves as a transmission surface for allowing external light from the front and rear surfaces of the light guide 50 to enter in order to ensure see-through performance.
Here, when the second surface 103b is not parallel to the X axis, that is, when the second surface 103b is inclined with respect to the surface of the light emitting unit 104 and the angle θb ≠ 0 ° is set, the light guide member 100. The image information guided in the inside changes because the reflection angle reflected by the second surface 103b and the reflection angle reflected by the light emitting unit 104 do not match.

Then, the incident angle θin defined by the angle formed by the light beam incident from the light beam incident unit 101 and the normal line of the light beam incident unit 101, the light beam emitted from the light beam emitting unit 104, and the normal line of the light beam emitting unit 104 The exit angle θout defined by the angle formed by is not the same angle. Further, when the image information is emitted to the outside of the light guide 50 through the first surface 103a and the light beam emitting unit 104, the image information is emitted in different directions, which is not considered as a virtual image.
For this reason, in the present embodiment, the angle θb = 0 °, and the second surface 103b is formed in parallel to the rear surface of the light emitting portion 104 (that is, to the X axis).
The third surface 103c that is an inclined surface has a role of ensuring a large area of the first surface 103a and improving the bending strength of the light guide member 100.
An angle θc of the third surface 103c with respect to the light emitting portion 104 is set to a range of greater than 0 ° and 90 °. When the angle θc is 90 °, the third surface 103c is the same surface as the second surface 103b, that is, a part of the second surface 102b, and thus has the same configuration as that described above. In addition, the angle θc is preferably in the range of 2 ° to 45 ° in consideration of productivity. Furthermore, since the third surface 103c causes a phenomenon such as irregular reflection when the image information from the image display element 10 hits, it is preferable that the third surface 103c has an angle range where the image information from the image display element 10 does not hit as much as possible. .

FIG. 8 is an enlarged view of a boundary surface between the light guide member 100 and the optical member 200 (surface 213 and surface 214; see FIG. 5) of the present invention. As shown also in FIG. 5, the optical member 200 is disposed close to the image extraction unit 103 of the light guide member 100. The optical member 200 has a slope (surface 214) having the same angle as the “inclination angle” of the surface of the image extraction unit 103 and is disposed at a position facing the surface of the light guide member 100 where the image extraction unit 103 is located. At this time, the light guide member 100 and the optical member 200 are preferably made of the same material.
As will be described later, the light guide member 100 and the optical member 200 (the surface 213 and the surface 214) can be integrated by an adhesive method. In this case, the refractive index of the adhesive is desirably lower than or equal to the refractive index of the light guide member 100. Thereby, total reflection of the light incident on the light guide member 100 from the light incident part 101 on the second surface 103b is maintained, and the transparency of external light such as scenery (see-through property of external light) is maintained. Is possible.

When the refractive index of the material of the light guide member 100 is equal to the refractive index of the adhesive, reflection at the interface is possible by applying a coat such as a half mirror to the adhesive interface, and see-through property is improved. It becomes possible to raise. When the refractive index of the adhesive is higher than that of the light guide member 100, the light beam is not totally reflected but is refracted at the adhesive portion, so that the virtual image display device is not established.
In addition, the light guide member 100 and the optical member 200 may not be integrated via an adhesive, but may be disposed via an air gap therebetween. In this case, the thickness of the air gap can be adjusted with high accuracy by holding the periphery of the air gap with a spacing member having a predetermined thickness, or by dispersing a spacer member (not shown) having a predetermined diameter inside the air gap. Can be maintained.
Details of the light guide will be described later.

(Embodiment 1)
Next, the configuration of the first embodiment will be described with reference to FIGS. 9, 10A, and 10B.
As shown in FIGS. 9, 10A, and 10B, the light guide 50 faces the image extraction portion 103 of the light guide member 100 (refractive index: N1), and the optical member 200 (refractive index: N2) is disposed. Configured. The image extraction unit 103 has the shape shown in FIGS.
In the first embodiment, the light guide member 100 and the optical member 200 are made of the same material (that is, N1 = N2). However, in general, different materials may be used. An air gap may be provided between the light guide member 100 and the optical member 200 (between the surface 213 of the light guide member 100 and the surface 214 of the optical member 200; see FIG. 5), or an adhesive layer (refractive index: N5). ) May be integrated by bonding.
At this time, when the adhesive layer is interposed,
N1> N5, N2> N5
Is desirable. Also,
N1 ≒ N5, N2 ≒ N5
In this case, by applying a coating process such as a half mirror to the bonding interface, reflection at the interface can be performed and see-through performance can be improved.

In order to prevent the relative positional relationship between the light guide member 100 and the optical member 200 from being shifted due to an impact such as impact or temperature change during use by the user, as shown in FIG. 50 (the surface on the + Y side of the Y axis, hereinafter simply referred to as “+ Y side”, the same applies to the X axis and the Z axis) and the lower surface (the surface on the −Y side of the Y axis, hereinafter simply referred to as “−Y side” It is desirable that the reinforcing members 605a and 605b are attached to at least one of the X-axis and the Z-axis) by, for example, an adhesive method.
At this time, it is possible to ensure the adhesive strength by applying an adhesive to the entire adhesive surface. This is a particularly effective means when the light guide member 100 and the optical member 200 are arranged via an air gap.
The materials described here are the same in other embodiments and modifications.
In the first embodiment, as shown in FIG. 9, a transparent member is provided on each of the + Z side surface (front surface) and the −Z side surface (rear surface) of the light guide 50 (that is, the light guide member 100 and the optical member 200). 600a and 600b were arranged.

The surface 105 and the surface 210 are configured to be substantially the same surface, and the transparent member 600a is integrated by the adhesive layer 601a. The adhesive layer 601 a is provided on the entire surface 105 and surface 210. Similarly, the surfaces 106 and 212 are configured to be substantially the same surface, and the transparent member 600b is integrated by the adhesive layer 601b. The adhesive layer 601b is provided on the entire surface 106 and the surface 212.
By providing the adhesive layers 601a and 601b on the entire surface of the transparent members 600a and 600b as described above, it is possible to prevent the adhesive layer from being peeled off due to an impact or a temperature change during use by the user.

To summarize the above, an image display element for displaying image information which is a virtual image, a coupling optical system for coupling image information of the image display element, and the image information coupled by the coupling optical system A virtual image optical system comprising a light guide for guiding and emitting the light,
The light guide 50 includes a light guide member 100 and an optical member 200.
The light guide member 100 is
A light beam incident part 101 for making image information incident on the inside,
An image retrieval unit 103 for retrieving image information to the outside;
A light emitting unit 104 for emitting image information to the outside,
The optical member 200 has a surface 212 that is disposed in the vicinity of the image extraction unit 103 of the light guide member 100 and that is disposed in parallel to face the light emitting unit 104.
At least one outermost surface of the light guide 50 is covered with a single continuous covering layer (corresponding to claim 1).

Next, the refractive index of the light guide member 100 is N1, the refractive index of the optical member 200 is N2, the refractive indexes of the adhesive layers 601a and 601b are N4a and N4b, and the refractive indexes of the transparent members 600a and 600b are N3a and N3b. To do.
As described above, the light beam incident on the light guide member 100 from the light beam incident portion 101 needs to be totally reflected on the inner surfaces of the surface 105 and the surface 106. for that reason,
N1> N4a, N1> N4b
Need to be.
However, the refractive indexes of the adhesives 601a and 601b are both equal, and if this is N3,
N1> N3 and N2> N3
(Corresponding to claim 7).
When the above conditions are not satisfied, a coating process may be performed so that the light rays incident on the light guide member 100 from the light incident portion 101 are totally reflected on the inner surfaces of the surfaces 105 and 106.

As a result, the total reflection on the surface 105 and the surface 106 of the light beam (excluding the light beam emitted from the light beam emission unit 104 to the outside) from the light beam incident unit 101 to the light guide member 100 is maintained, and FIG. 7. As shown in FIG. 8, the light beam totally reflected by the second surface 103b is not totally reflected by the light emitting unit 104 but is emitted toward the outside (observer (user) side; -Z side). At the same time, it is possible to maintain the transparency of outside light such as scenery (see-through property of outside light). That is, the light beam incident on the light guide member 100 from the light beam incident portion 101 is totally reflected by the surface 105 and the surface 106 (and the 103a surface and the 103b surface) at an incident angle equal to or greater than a predetermined angle, and the predetermined incident angle. In the following description, the refractive index of each component may be set so as to transmit the surface 106 (light emitting portion 104).
In addition, in order to ensure the see-through property of outside light,
N3a <N4a, N3b> N4b
Is desirable.

Furthermore, according to the request | requirement of the angle of view which should ensure the transparency (external light see-through property) of external light, such as a scenery, an adhesive layer and an optical element (the light guide member 100, the optical member 200, transparent member 600a, 600b) Each of the boundary surfaces (surface on the optical element side) may be subjected to a coating treatment for improving the transmittance (that is, reducing the reflectance).
In the configuration in which the transparent members 600 a and 600 b are not bonded to the light guide 50 (FIG. 4), the processing (dimension) accuracy of the light guide member 100 and the optical member 200 is insufficient, or the light guide member 100 and the optical member 200. When the positioning accuracy is insufficient, the front edge portion (acute angle portion) 211a protrudes outside the surface 105 (+ Z side), or the rear surface edge portion (acute angle portion) 211b is outside the surface 212. There is a risk of projecting to (-Z side). In such a case,
・ Dust etc. tend to accumulate near the acute angle part. ・ Easy to break starting from the acute angle part. ・ The user may touch the acute angle part (injuries).
Such problems are likely to occur.

On the other hand, in the configuration (FIG. 9) in which the transparent members 600a and 600b are bonded to the light guide 50 according to the first embodiment, the outermost surfaces (surfaces on the air side) of the transparent members 600a and 600b are each single. Consists of continuous surfaces.
As a result, the occurrence of the above problem can be effectively avoided. Further, since the light guide member 100, the optical member 200, and the transparent members 600a and 600b are integrated by the bonding method, the distance between the light guide member 100 and the optical member 200 (the distance between the surface 213 and the surface 214) is appropriate. It becomes possible to keep it.
The transparent members 600a and 600b are preferably made of a material having a surface hardness higher than that of the light guide member 100 and the optical member 200 (corresponding to claim 4).
For example, when the material of the light guide member 100 and the optical member 200 is resin, the transparent members 600a and 600b may be made of glass. Alternatively, when the transparent members 600a and 600b, the light guide member 100, and the optical member 200 are made of the same material, the surface (at least the air-side surface) of the transparent members 600a and 600b may be cured. Thereby, the transparent member functions as a “protective film”, and it is possible to suppress damage to the surface of the light guide 50.

Further, as the transparent member, it is also possible to select a material that is easier to be subjected to various coatings such as polarization treatment on the surface than the light guide member 100 and the optical member 200.
As shown in FIG. 10C, reinforcing members 605a for maintaining the relative positional relationship between the light guide member 100 and the optical member 200 on the side surfaces perpendicular to the front surface (+ Y side) and the rear surface (−Y side) of the light guide 50, It is desirable to bond 605b (corresponding to claim 14).
At this time, it is possible to ensure the adhesive strength by applying an adhesive to the entire adhesive surface. This is particularly effective when the light guide member 100 and the optical member 200 are arranged via an air gap.

(Configuration of coupling optical system)
Next, the configuration of the coupling optical system 300 and the principle of the virtual image optical system using the same will be described.
FIG. 3 shows how the light (image information) from the image display element 10 reaches the eyes of the observer (user) via the light guide 50.
Position information, which is image information of the image display element 10, is converted into an angle in a coupling optical system (also referred to as a collimator optical system) 300, enters the light beam incident portion 101 of the light guide 50, and the light beam of the light guide 50. Injected from the injection unit 104 to the outside. This indicates that the light is emitted while the incident angle of the coupling optical system 300 is preserved.
When this relationship is not maintained, image information that is a light beam emitted from the image display element 10 is emitted at different angles when emitted from the light guide 50, and therefore, an image that is not desirable as a virtual image. Become.

More specifically, as shown in FIG. 3, image information A, B, and C are output from the center and both ends of the image display element 10, respectively. The position information of the image information is converted into angle information θA, θB, and θC through the coupling optical system 300. Such image information is emitted from the coupling optical system 300 and enters the light incident portion 101 of the light guide 50. At this time, the image information A is incident on the light incident portion 101 at an angle of θA, the image information B is incident at an angle of θB, and the image information C is incident at an angle of θC. In order to facilitate understanding, in FIG. 3, for image information A, B, and C emitted from the coupling optical system 300, θA is a solid line “-”, and θB is an alternate long and short dash line “-•-”, θC. Is indicated by a dotted line "...".
Thus, the image information incident on the incident portion 101 is guided into the light guide 50, and the image information A, B, and C moves inside the light guide 50. When each piece of image information A, B, and C is emitted from the light emitting unit 104 of the light guide 50, the incident angles of θA, θB, and θC in each piece of image information are stored as shown in FIG. It is injected in the state.

  As described above, in this embodiment, the incident angle of each light beam constituting the image information emitted from the coupling optical system 300, that is, the light beam emitted from the light beam emitting unit 104 of the light guide 50 in a state where the angle information is stored. Therefore, a high-quality virtual image can be displayed.

The optical system is illustrated in FIG. 3 in the case where the coupling optical system 300 has a configuration of four lenses in three groups, but is not limited thereto. The coupling optical system 300 may have other configurations, for example, a configuration with two lenses, or five or more lenses.
The virtual image optical system of the first embodiment as described above does not have an acute angle portion formed on the outermost surface, thereby avoiding the adhesion / deposition of dust on the acute angle portion and preventing the acute angle portion itself from being lost. In addition, it is possible to provide a virtual image optical system including a light transmissive substrate (light guide) that is not injured by the user.

(Embodiment 2)
FIGS. 11 to 14 show the configuration of Embodiment 2 of the virtual image optical system according to the present invention.
In the second embodiment, the transparent member 600a is disposed only on the outermost surface on the + Z side of the outermost surface on the front surface side of the light guide 50 (that is, the light guide member 100 and the optical member 200). It is desirable to dispose at least the transparent member 600a on the surface on the + Z side of the light guide 50 to which dust in the air is likely to adhere (corresponding to claim 2).
In the second embodiment, the light guide 50 and the transparent member 600a are integrated by the adhesive layer 601. The adhesive layer 601 a is provided on the entire surface of the surface (front surface) 105 of the light guide member 100 and the opposing surface (front surface) 210 of the optical member 200. Adopting a configuration in which the adhesive layer is applied to the entire surface of the adhesive surface improves the adhesive strength. This is a preferred configuration for solving the problem (corresponding to claim 5).
At this time, when the thickness of the adhesive layer 601a is large, as shown in FIG. 14, a spacing member 604 having a predetermined thickness (dimension in the Z-axis direction) is provided around the entire periphery of the adhesive layer 601a. Thereby, the thickness of the adhesive layer 601a can be made uniform. Further, by dispersing and arranging spacer members (not shown) having the same diameter as the thickness of the adhesive layer in the adhesive layer 601a, it is possible to further ensure the thickness uniformity.

(Modification 1 of Embodiment 2)
FIG. 15 shows a first modification of the second embodiment. The difference from the second embodiment is that no spacing member is used. When the thickness of the adhesive layer 601a is thin, the spacing member 604 shown in the second embodiment is not necessarily provided. As in the case of the second embodiment, the adhesive layer 601a is provided over the entire surface 105 of the light guide member 100 and the surface 210 of the optical member 200 (corresponding to claims 2 and 3).

(Embodiment 3)
FIG. 16, FIG. 17, FIG. 18A, FIG. 18B, and FIG. 18C show the configuration of Embodiment 3 of the virtual image optical system according to the present invention.
As shown in FIG. 16, in the light guide 50 of the third embodiment, the front surface 210 of the optical member 200 is higher than the front surface 105 of the light guide member 100 (that is, the front surface 210 is positioned on the + Z side). It is configured as follows. This is a state where an acute angle portion is formed on the outermost surface as it is.
As shown in FIGS. 17 and 18A to 18C, the optical member 200 and the transparent member 600a are integrated by an adhesive layer 601a. The adhesive layer 601 a is provided on the entire front surface 210 of the optical member 200. On the other hand, the light guide member 100 and the transparent member 600 a are disposed via the air gap 602.

In order to secure the air gap 602, a spacing member 604 is provided at or near the periphery of three sides (+ X side, + Y side, −Y side sides) of the + Z side front surface 105 of the light guide member 100. The transparent member 600a is disposed so that the gap holding member 604 is disposed in the peripheral part of the transparent member 600a in the region facing the light guide member 100, and the air gap 602 is formed in a part other than the peripheral part. An adhesive layer 601a is formed with an adhesive in a region facing 200 (corresponding to claim 6). Further, by dispersing and arranging spacer members (not shown) having the same diameter as the thickness in the air gap 602, it is possible to further ensure the uniformity of the thickness.
Thus, by providing the air gap 602 between the surface 105 and the transparent member 600a, the light incident on the light guide member 100 from the light incident portion 101 can be totally reflected by the surface 105 which is the inner surface. Since the range of incident angles that can be expanded is widened, this is a preferable configuration.

(Modification 1 of Embodiment 3)
19 and 20A to 20C show the configuration of the first modification of the third embodiment. The light guide 50 (the light guide member 100 and the optical member 200) has the same configuration as shown in FIG.
As shown in FIG. 19, in the first modification, the opposing surface 210 and the transparent member 600a are integrated by an adhesive layer 601a. The adhesive layer 601a is provided on the entire front surface 210 that faces the adhesive layer 601a.
On the other hand, the surface 105 of the light guide member 100 and the transparent member 600a are also integrated by the adhesive layer 601a. However, as shown in FIG. 20B, three sides (+ X side, + Y side, The adhesive layer 601a is provided over a certain width only on the outermost periphery of the −Y side) or in the vicinity thereof. Thereby, an air gap 602 having the same thickness as the adhesive layer 601a can be secured between the surface 105 and the transparent member 600a. Further, by dispersing and arranging spacer members (not shown) having the same diameter as the thickness in the air gap 602, it is possible to further ensure the uniformity of the thickness.
Thus, by providing the air gap 602 between the surface 105 and the transparent member 600, the light incident on the light guide member 100 from the light incident portion 101 is totally reflected by the surface 105 (inner surface) that is the inner surface. Can do.

If the refractive index of the light guide member 100 is N1, the refractive index of the optical member 200 is N2, the refractive index of the transparent member 600a is N3a, and the refractive index of the adhesive layer 601a is N4a, In order for the light incident on the light guide member 100 to be totally reflected by the surface 105,
N1> N4a
Need to be.
In addition, in order to ensure the see-through property of outside light,
N3a <N4a <N2
Is desirable. As a result, the light incident on the light guide member 100 from the light incident part 101 is totally reflected by the surface 105, the surface 106, and the surface 213 of the image extraction unit 103, and also transmits external light such as scenery (see-through of external light). Property).
FIG. 20C shows an assembly diagram of Modification 1 of Embodiment 3.

(Embodiment 4)
The configuration of the fourth embodiment is shown in FIGS. 21A to 21B and FIGS. 22A to 22B.
As shown in FIG. 21A, an extending portion 603 is provided on the + Z side surface of the optical member 200. The extending portion 603 has a shape extended toward the light incident portion 101 side (+ X side) so as to cover the surface 105 of the light guide member 100. The surface of the extending portion 603 (the surface on the + Z side) is a single continuous surface. Therefore, since it does not have a shape corresponding to the edge portion (acute angle portion) 211 (see FIG. 16 and the like) shown in the second embodiment or the like, this is a preferable configuration.
On the other hand, the transparent member 600b is arranged on the light guide 50, that is, on the −Z side surface of the light guide member 100 and the optical member 200, as in the first embodiment shown in FIG. As a result, the edge portion (acute angle portion) 211b is not the outermost surface of the light guide 50, which is a preferable configuration.

FIG. 21B shows a state before assembling each member having the configuration of the fourth embodiment. An exploded perspective view of the configuration of the fourth embodiment is shown in FIG. 22A. The hatched portions in the figure indicate adhesive layers 601a, 601b, and 601c.
The adhesive layer 601a bonds the surface 105 and the surface 215, the adhesive layer 601b bonds the surface 216, the surface 106, and the surface 212, and the adhesive layer 601c bonds the surface 214 and the surface 213. The adhesive layers 601a, 601b, and 601c are provided on the entire adhesion surface.
When the refractive index of the light guide member 100 is N1, the refractive index of the optical member 200 is N2, the refractive index of the transparent member 600b is N3, and the refractive indexes of the adhesive layers 601a, 601b, and 601c are N4, the light is guided from the light incident portion 101. In order for the light incident on the member 100 to be totally reflected by the surface 105,
N1> N4
Need to be.
In addition, in order to ensure the see-through property of outside light,
N2> N4, N3> N4
Is desirable. As a result, the light incident on the light guide member 100 from the light incident part 101 is totally reflected by the surface 105, the surface 106, and the surface 213 of the image extraction unit 103, and also transmits external light such as scenery (see-through of external light). Property).

When the adhesive layer is thick, the thickness of the adhesive layer is ensured by providing a spacing member around the periphery of the adhesive layer or in the vicinity thereof, or by dispersing spacer members inside the adhesive layer. Is possible.
Similarly to FIG. 10C according to the first embodiment, also in the fourth embodiment, the reinforcing members 605a and 605b may be bonded to at least one of the upper surface and the lower surface of the light guide 50 as illustrated in FIG. 22B. .

(Modification 1 of Embodiment 4)
23 to 29 show configurations of Modifications 1 to 7 of the fourth embodiment.
FIG. 23 shows a configuration of a first modification of the fourth embodiment.
The hatched portions in FIG. 23 indicate adhesive layers 601a, 601b, and 601c, as in the fourth embodiment shown in FIGS. The adhesive layer 601a bonds the surface 105 and the surface 215, the adhesive layer 601b bonds the surface 216, the surface 106, and the surface 212, and the adhesive layer 601c bonds the surface 214 and the surface 213. The adhesive layers 601b and 601c are provided on the entire adhesive surface as in the fourth embodiment.
On the other hand, in the adhesive layer 601 a, the adhesive layer 601 a is provided over a certain width only on the outermost four sides of the surface 215, and an inner region surrounded by the adhesive layer 601 a becomes an air gap 602. Also in this case, it is possible to ensure the uniformity of the thickness by dispersing and arranging spacer members (not shown) in the air gap 602.

(Modification 2 of Embodiment 4)
FIG. 24 shows a configuration of a second modification of the fourth embodiment.
The hatched portions of the second to seventh modifications of the fourth embodiment shown in these drawings represent the adhesive layers 601a, 601b, and 601c as in the first modification, and the areas that are not hatched are the air gaps 602. Represents that. In these examples as well, it is possible to ensure uniformity of the thickness of the air gap 602 by dispersing and arranging spacer members (not shown) in the air gap 602.
In addition, the angle at which the light incident on the light guide member 100 from the light incident portion 101 is totally reflected by the surface 105, the surface 106, and the image extraction portion 103 (surface 213), and the transparency of external light such as scenery (see-through of external light). For the property), the refractive index of the adhesive layer and the region of the adhesive layer and the air gap may be appropriately set according to the request for the angle of view to be secured.
FIG. 25 shows a configuration of a third modification of the fourth embodiment.
In the third modification, the surface 214 of the optical member 200 and the surface 215 of the extending portion 603, and the adhesive layer 601c and the adhesive layer 601c between the surfaces 213 and 105 of the light guide member 100 are formed in the peripheral portion. An air gap 602 is formed inside the periphery.

Moreover, in the modification 4 of Embodiment 4, as shown in FIG. 26, the example which provided the air gap 600 in the part of the contact bonding layer 601b between the light guide member 100, the surface 216, and the surface of the transparent member 600b. Indicates.
In the fifth modification of the fourth embodiment, the air is formed inside the adhesive layers 601 c and 601 a between the surface 214 of the optical member 200 and the surface 215 of the extending portion 603 and the surfaces 213 and 105 of the light guide member 100. A gap 602 is provided, and an air gap 602 is also provided inside the adhesive layer 601b between the light guide member 100 and the transparent member 600b.
In the sixth modification of the fourth embodiment, the air gap 602 is provided only in the adhesive layer 601 a between the surface 105 of the optical member 100 and the extending portion 603.
In the seventh modification of the fourth embodiment, as shown in FIG. 29, the air gap 602 joins between the light guide member 100 and the optical member 200 and between the light guide member 100 and the transparent member 600b. The adhesive layers 601a and 601b to be provided are provided.

(Embodiment 5)
30A to 30C further show the configuration of the fifth embodiment.
As illustrated in FIG. 30A, the fifth embodiment has a configuration in which the transparent member 600b included in the fourth embodiment is omitted. As described above, the extending portion 603 obtained by extending the optical member 200 is provided on the + Z side surface of the light guide 50 to which dust in the air easily adheres, and a single continuous surface is disposed on the forefront of the light guide 50. It is desirable (corresponding to claim 8).
FIG. 30B is a diagram illustrating a correspondence between the light guide member 100 and the optical member 200 of each component according to the fifth embodiment.
As shown in FIG. 30C, in the fifth embodiment, the adhesive layer 601a has a configuration similar to that of the sixth modification of the fourth embodiment (see FIG. 28). The adhesive layer 601 a is provided with a constant width only on the four sides of the periphery of the surface 215, and an intermediate region surrounded by the adhesive layer 601 a becomes an air gap 602. The adhesive layer 601 c is provided on the entire surface 214.
As in the fourth embodiment and its modification, the angle at which the light incident on the light guide member 100 from the light incident unit 101 is totally reflected by the surface 105, the surface 106, and the image extraction unit 103 (surface 213), scenery, etc. With regard to the transmittance of outside light (see-through property of outside light), the refractive index of the adhesive layer and the area of the adhesive layer and the air gap may be appropriately set according to the request for the angle of view to be secured.

(Modification 1 of Embodiment 5)
FIG. 31 shows a configuration of a first modification of the fifth embodiment.
The difference from the fourth embodiment is that the extending portion 603b is also provided on the surface 106 (the surface on the −Z side) of the light guide member 100. The extending portion 603b has a shape extended to the opposite side (−X side) from the light incident portion 101 so as to cover the surface 212 of the optical member 200. The surface of the extending portion 603b (the surface on the −Z side) is a single continuous surface (corresponding to claim 8). Therefore, since it does not have a shape corresponding to the edge part (acute angle part) 211 (see FIG. 11 etc.) shown in the second embodiment, etc., it is a preferable configuration.

(Embodiment 6)
FIG. 32 shows the configuration of the sixth embodiment.
The sixth embodiment has substantially the same configuration as that of the modified example (FIG. 15) of the second embodiment, but has a configuration in which the transparent member 600 in the modified example 2 is replaced with a transmittance varying unit 700. In this case, a transparent member 600b that functions similarly to a protective film or the like may be attached to the surface 106 side.
The transmittance varying means 700 can employ electrochromic, liquid crystal, or the like that can drive / control the transmittance with an electric signal (corresponding to claim 9).
When the image information (virtual image) by the virtual image display device is difficult to view due to the influence of the brightness and color of outside light such as scenery, the transmittance varying means 700 responds to the landscape transmittance (see-through of external light) according to this image information. It is possible to appropriately adjust the property (corresponding to claim 10). Furthermore, it is desirable to provide an operation unit in the virtual image optical system or the virtual image display device so that the user can adjust the transmittance.

In addition, control means is provided for controlling to reduce the transmittance of scenery (see-through property of external light) when the image to be displayed (virtual image) is dark and to improve the transmittance when the image to be displayed is bright. Is desirable. Thereby, even if a user does not operate, the fall of the visibility of an image can be avoided and an appropriate image can be visually observed.
Furthermore, it is desirable to provide an illuminance sensor for detecting ambient brightness in the virtual image optical system or the virtual image display device. By comparing the brightness detection result by the illuminance sensor with the brightness of the image to be displayed, and by providing a control means for controlling the transmittance according to the result, it is possible to view an appropriate image without the user's operation (Corresponding to claim 11).

(Embodiment 7)
FIG. 33 shows the configuration of the seventh embodiment.
In the first to fifth embodiments, the optical member 200 is arranged facing the image extraction unit 103 of the light guide member 100. However, in the seventh embodiment, the optical member 200 is omitted by providing the interval holding member 220. The configuration was as follows.
Since the optical member 200 is not disposed in this way, cost reduction and weight reduction can be achieved.
Further, by disposing the spacing member 220, it is possible to avoid the transparent member 600a from being easily damaged.
Since the edge part (acute angle part) 211b is configured to be covered with the transparent member 600b, it is possible to avoid the edge part (acute angle part) 211b from being lost or being injured when the user touches carelessly. It becomes.

That is, the above-described point will be described in more detail. The light guide 60 covers the light guide member 100 and the front side (+ Z side) of the light guide member 100 and has an extending portion that is longer than the entire length of the light guide member 100. A front transparent member 600a;
A rear surface side transparent member 600b that covers the rear surface side (−Z side) of the light guide member 100 and has an extending portion longer than the entire length of the light guide member 100;
A spacing member 220 interposed between the opposing extending portions of the front transparent member 600a and the rear transparent member 600b;
Between the light guide member 100 and the front transparent member 600a, between the light guide member 100 and the rear transparent member 600b, between the spacing member 220 and the extending portion of the front transparent member 600a, and the spacing member 220. And the rear surface side transparent member 600b are composed of adhesive layers 601a, 601b and 601C made of an adhesive to be joined.
The light guide 60 configured as described above has an air gap formed in a portion surrounded by the extending portion of the front transparent member 600a, the image extracting portion 103 of the light guide member 100, and the spacing member 200. (Corresponding to claim 13).

(Embodiment 8)
FIG. 34 shows the configuration of the eighth embodiment.
In the eighth embodiment, among the light rays that are the image information reflected by the image extraction unit 103, for example, compared with the light rays reflected at the point P1 and the point P2, the light is reflected at the point P3 near the −X side end. When light rays enter the eyes of an observer (user), the brightness tends to be dark. Therefore, the virtual image (image information) near the right end (−X law end) of the visual field of the observer (user) becomes darker than the brightness of the external light, and the observer (user) has an unnatural image (virtual image). + External light).
Therefore, it is desirable to change the transmittance only in the area A corresponding to the vicinity of the right end of the visual field of the observer (user) in the transmittance varying means 700. That is, it is desirable that the transmittance varying means can vary only the transmittance of the field of view corresponding to the light beam reflected in the vicinity of the light incident portion or the end near the light incident portion 101 in the image extraction unit 103 ( Corresponding to claim 12). Thus, by reducing the transmittance in the area A, it is possible to avoid feeling unnaturalness as the brightness of the entire image, and a preferable configuration.
As described above, the various embodiments 1 to 8 described above realize a virtual image optical system suitable for a virtual image display device including a light guide that is compact and does not have an acute angle portion formed on the outermost surface (front side surface and rear side surface). The

(Virtual image display device)
FIG. 35 shows a configuration of a virtual image display device using the above-described light guides 50 and 60 and a virtual image optical system. In the figure, the ray path of the image information is indicated by arrows, and the eyes of the observer (user), that is, the user are schematically drawn. The virtual image display device shown in FIG. 2 is obtained by adding a light source LS for illuminating the image display element 10 to the virtual image optical system shown in FIG. 2, the image display element 10 for displaying a virtual image, and the image display. The positional relationship between the coupling optical system 300 that couples image information of the element 10 to the light guide 50 and the light guide 50 that guides image information that is enlarged and incident by the coupling optical system 300 is shown. .
Description of the same parts as those in FIG. 2 is omitted. As the image display element 10, LCOS, DMD, or the like that requires a light source is used. Various light sources LS can be applied. For example, an LED (Light Emitting Diode), a semiconductor laser (Laser Diode: LD), a discharge lamp, or the like can be used.

According to such a virtual image display device, the image information of the image display element 10 illuminated by the light source LS is enlarged by the coupling optical system 300 and enters the light guide 50. That is, the image information enlarged by the coupling optical system 300 is incident from the light beam incident portion 101 of the light guide member 100 in the light guide 50 and guided to the inside of the light guide member 100. The guided image information is reflected by the image extraction unit 103 and is emitted as image information from the light emitting unit 104 toward both eyes of the user. The user can visually recognize the virtual image of the image information by looking forward through the light emitting unit 104 of the light guide member 100.
In the first to eighth embodiments described above, an example in which the light beam incident portion 101 of the light guide member 100 is arranged on the left side of the virtual image observer (user) and the image information is incident from the left side of the virtual image observer (user) has been described. . When such an arrangement is reversed left and right, that is, when the light beam incident portion 101 of the light guide member 100 is arranged on the right side of the virtual image observer (user) and the image information is incident from the right side of the virtual image observer (user). The same effect as described above can be obtained.
The case where the light guide 50 of Embodiments 1 to 8 described above is applied to a glasses-type virtual image display device, that is, an HMD is illustrated in FIGS.

The example shown in FIG. 36A is a case where one light guide 50 is applied to an HMD for both eyes, and the light incident portion 101 of the light guide member 100 is arranged on the right side of the user. The light guide 50 is fixed to the frame part 400 that plays a role as a vine hung on the user's ear. In FIG. 36A, the frame portion 400 is simplified, but the frame portion 400 can be shaped to cover not only both ends of the light guide 50 but also the upper edge and the lower edge.
Further, the example shown in FIGS. 38B and 38C is a case where one light guide 50 is miniaturized and applied to a monocular HMD. The example shown in FIG. 38B is a case where the two light guides 50 and 50 are arranged corresponding to the positions of the left and right eyes of the user, and the light beam incident portions 101 of the respective light guides are arranged on the left and right outer sides. Is done.
36, the virtual image optical system and the light source are not shown, but these can be attached to the frame unit 400. That is, in the example shown in FIGS. 36A and 36C, the light source LS, the image display element 10, and the coupling optical system 300 are placed on the right eye frame, and in the example shown in FIG. What is necessary is just to attach to a frame part.

In the above-described embodiment, the case where the light guide 50 is applied to an eyeglass-type HMD has been described. On the other hand, the above-described light guide 50 can be applied to other types of HMDs, and can also be applied to a virtual image display device such as a head-up display (HUD) including the above-described virtual image optical system. The light guide 50 (corresponding to claim 15) is particularly suitable for displaying a virtual image of an original image formed by a light beam light-modulated by a microdevice.
As described above, according to the first to eighth embodiments and the modifications thereof according to the present invention, the acute angle portion is not formed on the outermost surface, thereby avoiding the adhesion / deposition of dust on the acute angle portion. It is possible to provide a virtual image optical system provided with a light-transmitting substrate (light guide) that prevents the portion itself from being lost and does not injure the user.

DESCRIPTION OF SYMBOLS 10 Image display element 300 Coupling optical system LS Light source 50, 60 Light guide 100 Light guide member 101 Light incident part 103 Image extraction part 103a 1st surface 103b 2nd surface 103c 3rd surface 104 Light emission part 105 surface (front side)
106 surfaces (surfaces on the light emitting portion 104 side of the light guide member 100, rear side surfaces)
140, 602 Air gap 200 Optical member 210 Opposite surfaces (front surface, FIG. 5, FIG. 11, etc.)
211a Edge part (acute angle part) (FIG. 11)
211b Edge part (acute angle part) (same as above)
212 to 216 surface 400 frame portion 600 transparent member 600a, 600b transparent member 601a, 601b, 601c adhesive layer 602 air gap 603a, 603b, 603c extending portion 604 interval holding member 605a, 605b reinforcing member 700 transmittance variable means (FIG. 25)

Japanese Patent No. 4508655

Claims (15)

An image display element for displaying image information which is a virtual image, a coupling optical system for coupling image information of the image display element, and light emission by guiding the image information coupled by the coupling optical system A virtual image optical system comprising a light guide for emitting from a portion,
The light guide has a light guide member and an optical member,
The light guide member is
A light incident part for making the image information incident on the inside thereof;
An image extraction unit for extracting the image information to the outside;
A light emitting part for emitting the image information to the outside,
The optical member has a surface disposed in proximity to the image extraction unit of the light guide member and disposed in parallel to face the light emitting unit,
At least one outermost surface of the light guide is coated with a single continuous coating layer.   The virtual image optical system according to claim 1, wherein the outermost surface is an outermost surface on a front surface side of the light guide.   The virtual image optical system according to claim 1, wherein the single continuous coating layer is made of a transparent member.   The virtual image optical system according to claim 3, wherein the transparent member has a hardness higher than that of the light guide member and the optical member.   The virtual image optical system according to claim 2, wherein the transparent member is disposed on a front surface of the light guide via an adhesive layer.   The transparent member is disposed such that a spacing member is disposed in a peripheral portion of the transparent member in a region facing the light guide member, and a portion other than the peripheral portion is used as an air gap, and the optical member is disposed in the optical member. The virtual image optical system according to claim 3, wherein the opposing regions are arranged via an adhesive. When the refractive index of the light guide member is N1, the refractive index of the optical member is N2, and the refractive index of the adhesive layer is N3,
7. The virtual image optical system according to claim 5, wherein N1> N3 and N2> N3.   The single continuous covering layer is formed by covering the front surface of the light guide with the optical member provided with an extending portion obtained by extending the optical member toward the light guide member, or The light guide member formed by extending a light guide member toward the optical member is covered with a rear surface of the light guide. The virtual image optical system of any one of 1-3.   The virtual image optical system according to any one of claims 3 to 8, wherein the virtual image optical system includes a transmittance varying unit that varies the transmittance of external light incident on the light guide, instead of the transparent member. Optical system.   The virtual image optical system according to claim 9, wherein the transmittance varying unit varies the transmittance according to the image information.   The virtual image optical system further includes an illuminance sensor that detects ambient brightness, and the transmittance varying unit varies the transmittance according to a detection result of the illuminance sensor. Or the virtual image optical system according to 10;   The transmissivity variable means only transmits the transmissivity of the region of the field of view corresponding to the light beam reflected in the vicinity of the light incident portion side end portion or in the vicinity of the end portion on the opposite side of the light ray incident portion in the image extracting portion. The virtual image optical system according to claim 9, wherein the virtual image optical system is variable. An image display element for displaying image information which is a virtual image, a coupling optical system for coupling image information of the image display element, and light emission by guiding the image information coupled by the coupling optical system A virtual image optical system comprising a light guide for emitting from a portion,
The light guide includes a light guide member, a front side transparent member that covers the front side of the light guide member and has an extending portion that is longer than the entire length of the light guide member,
The rear side transparent member that covers the rear side of the light guide member and has an extended portion longer than the entire length of the light guide member;
An interval holding member interposed between the extending portions facing the front transparent member and the rear transparent member;
Between the front surface of the light guide member and the front transparent member, between the rear surface of the light guide member and the rear transparent member, between the spacing member and the extending portion of the front transparent member, and An adhesive layer that joins between the spacing member and the extending portion of the rear transparent member,
A virtual image optical system, wherein an air gap is formed in a portion surrounded by the extending portion of the front transparent member, the image extraction portion of the light guide member, and the spacing member. The virtual image optical system further includes a reinforcing member for maintaining a relative positional relationship between the light guide member and the optical member on a side surface perpendicular to a front surface and a rear surface of the light guide. Item 14. The virtual image optical system according to any one of Items 1 to 13.   A virtual image display device comprising the virtual image optical system according to claim 1.

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