JP2021149008A - Light guide body and virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide body which can suppress luminance loss and is easy to manufacture, and a virtual image display device using the light guide body.
SOLUTION: The light guide body 300 that guides and emits light is composed of two or more light guide members including a first light guide member 310 and a second light guide member 320, and the light is emitted. The light incident portion 301, which is an incident surface, the light guide unit 302 that repeatedly reflects and guides the light incident from the light incident portion, and the light ray emitting unit 304 that emits light to the outside of the light guide body. The second light guide member has a parallel flat plate shape and has at least a light guide of the first light guide member. It is joined to the part.
[Selection diagram] Fig. 1

Description

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

As a virtual image display device, for example, an HMD (Head Mounted Display) has begun to spread. The HMD is classified into a see-through transmissive type and a non-transparent type, and a well-known transmissive HMD includes GOOGLE GLASS (registered trademark) and the like. Many non-transparent HMDs have been released by various companies because of their immersive feeling. Regarding the size of the virtual image that can be visually recognized by a human being by the virtual image display device, in the case of the transmissive type, it is small and portable because it is used in combination with an information terminal or in combination with AR (Augmented Reality). There is a tendency for something with good sex to be sought. On the other hand, in the case of the non-transparent type, since it is used in games or VR (Virtual Reality), there is a tendency that an immersive feeling is obtained and a wide viewing angle is required. A common feature of virtual image display devices is that those that specialize in reducing the size and thickness of the main body tend to have a narrow viewing angle, while when the display area is widened, the size of the main body is large. Tended to be larger and thicker. In recent years, even in the transmissive type, there has been a demand for a thin wall and a wide viewing angle due to the user's needs.

The techniques disclosed in Patent Documents 1 to 3 are known as those in line with such a request. However, in these techniques, light is emitted out of the light guide by reflection from a plurality of mirrors or a plurality of microstructures, and is guided to the user's eyes. In this case, there is light at an angle that does not correspond to the plurality of mirrors or the plurality of microstructures with respect to the light at each angle that guides the light guide body at an angle corresponding to each pixel of the image display element. Therefore, there has been a problem that a portion lacking brightness is generated in the observed virtual image.

In order to solve this problem, a layer that splits the light is provided inside the light guide plate, and the timing of reflection of light at various angles that guide the light inside the light guide plate is adjusted to allow light at an angle at which brightness loss is likely to occur. A method for eliminating luminance loss has been proposed so as to make it easier to hit a plurality of mirrors or a plurality of microstructures (Patent Document 4).

However, when a layer for splitting light is provided in the light guide body, it is necessary to provide the light guide body with a split surface so that the light guide body is divided into a plurality of parts and then joined via the split surface. The problem was that the difficulty level increased in making it.

In order to solve the above-mentioned problems of the prior art, it is an object of the present invention to provide a light guide body which can suppress luminance loss and is easy to manufacture, and a virtual image display device using the light guide body.

In order to solve the above-mentioned problems, the light guide body of the present invention is a light guide body that guides and emits light, and includes two or more guides including a first light guide member and a second light guide member. A light incident portion that is composed of an optical member and is a surface on which the light is incident, a light guide portion that repeatedly reflects and guides the light incident from the light incident portion, and the light guide. The second light guide member has a light emitting portion that emits light to the outside of the light body and a take-out portion that reflects the light guided by the light guide portion toward the light emitting portion. It has a flat plate shape and is joined to at least the light guide portion of the first light guide member.

According to the present invention, it is possible to realize a light guide body which can suppress the loss of brightness and is easy to manufacture.

FIG. 1 is a configuration diagram of a virtual image display device including a light guide according to the first embodiment. FIG. 2 is an enlarged view of a part of the light guide body according to the first embodiment. FIG. 3 is an enlarged view of a part of the light guide body according to the first embodiment. FIG. 4 is a configuration diagram of a virtual image display device including a light guide body according to a comparative form. FIG. 5 is a diagram showing an example of light rays guided by the light guide body according to the comparative form. FIG. 6 is a diagram showing an example of light rays guided by the light guide body according to the first embodiment. FIG. 7 is a block diagram of the light guide body according to the second embodiment. FIG. 8 is an enlarged view of a part of the light guide body according to the second embodiment. FIG. 9 is an enlarged view of a part of the light guide body according to the modified example of the second embodiment. FIG. 10 is a diagram showing another configuration example of the first light guide member. FIG. 11 is a diagram showing another configuration example of the take-out unit. FIG. 12 is a block diagram of the light guide body according to the third embodiment. FIG. 13 is a block diagram of the light guide body according to the fourth embodiment. FIG. 14 is a diagram showing the result of simulation calculation of the brightness distribution of the virtual image in the virtual image display device of the comparative example. FIG. 15 is a diagram showing the result of simulation calculation of the brightness distribution of the virtual image in the virtual image display device of the embodiment.

Hereinafter, embodiments of the light guide and the virtual image display device will be described in detail with reference to the drawings. Further, the present invention is not limited to the following embodiments, and the components in the following embodiments include those easily conceived by those skilled in the art, substantially the same, and so-called equal ranges. Includes. Furthermore, various omissions, substitutions, changes and combinations of components can be made without departing from the gist of the following embodiments.

(Virtual image display device including the light guide body according to the first embodiment)
FIG. 1 is a configuration diagram of a virtual image display device including a light guide according to the first embodiment. The virtual image display device 1000 includes an image display element 100, an optical system 200, and a light guide body 300 according to the first embodiment.

The image display element 100 is a device that emits image light of an image that is the basis of a virtual image displayed through the light guide body 300. The image display element 100 is a plate-shaped element that extends in the depth direction of the drawing. As the image display element 100, for example, various display elements such as an OLED (Organic Light Emitting Diode) or a liquid crystal display device can be applied. If the image display element 100 can display information such as an image, for example, a DMD (Digital Mirror Device) which is a MEMS (Micro Electrical Mechanical Systems) device in which a large number of micromirror surfaces (micromirrors) are arranged on a plane. ), Or LCOS (Liquid Crystal On Silicon) can be applied. In this case, as a light source for irradiating the image display element 100, for example, an LED (Light Emitting Diode), an LD (Laser Diode), a discharge lamp, or the like can be used.

The optical system 200 is composed of a plurality of optical lenses, apertures, and the like, and emits light rays containing image information emitted from the image display element 100 (hereinafter, may be simply referred to as “image light”) of the image display element 100. It is an optical system that changes the angle in the direction according to each position and makes it parallel.

The light guide body 300 for the virtual image display device guides the image light including the image information parallelized by the optical system 200 emitted from the image display element 100 in order to display the virtual image to the human eye. Inject. The light guide body 300 is a plate-shaped member extending in the depth direction of the drawing. The light guide body 300 includes a light ray incident portion 301, a light guide unit 302, an extraction unit 303, and a light ray emitting unit 304. Further, the light guide body 300 has a reflecting portion 305. The light ray incident portion 301, the light guide portion 302, the take-out portion 303, the light ray emitting portion 304, and the reflecting portion 305 extend in the depth direction of the drawing. In the longitudinal direction of the light guide body 300, which is the left-right direction of FIG. 1, the side where the light incident portion 301 is provided may be described as the proximal end side, and the side away from the light incident portion 301 may be described as the tip end side.

The light beam incident portion 301 is a portion located opposite to the optical system 200, which is emitted from the image display element 100 and in which the image light parallelized by the optical system 200 is incident. The reflection unit 305 is a portion that reflects the light beam of the image light incident from the light beam incident unit 301.

The light guide unit 302 has two substantially parallel main surfaces, and is a portion that guides the light rays reflected by the reflection unit 305 while repeatedly totally reflecting them between the two main surfaces.

The take-out unit 303 is a portion that reflects the light beam guided by the light guide unit 302 toward the light ray emitting unit 304 in order to take out the light beam to the outside of the light guide body 300. The light ray emitting unit 304 is a portion that emits light rays reflected by the extraction unit 303 to the outside of the light guide body 300 to be emitted to the outside of the light guide body 300. Therefore, the user of the virtual image display device 1000 can confirm the virtual image by looking into the light guide body 300 from the light emitting unit 304 side.

FIG. 2 is an enlarged view of a part of the light guide body 300 including the take-out portion 303. The take-out unit 303 has a plurality of surfaces 303a substantially parallel to the light ray emitting unit 304, and a plurality of surfaces 303b inclined with respect to the light ray emitting unit 304. The surfaces 303a and 303b are alternately arranged in the left-right direction of the drawing (the direction from the base end to the tip end of the light guide body 300).

When the light guided by the light guide unit 302 is repeatedly totally reflected and hits each surface 303b, it is reflected toward the light emission unit 304 as shown by, for example, the light ray R1. Further, by providing the surface 303a between the surfaces 303b, the light can travel toward the tip end side of the light guide body 300 until the light hits the surface 303b. As a result, the light can be guided to a portion of the light emitting portion 304 located on the tip side of the light guide body 300. As a result, it is possible to realize a virtual image display device 1000 capable of wide-angle display with a relatively thin light guide body 300.

Here, the light guide body 300 is composed of two light guide members, a first light guide member 310 and a second light guide member 320. In the light guide body 300, as shown in FIG. 1, the light ray incident portion 301, the light guide unit 302, the extraction unit 303, the light ray emitting unit 304, and the reflection unit 305 are provided on the first light guide member 310. Further, in the light guide body 300, the first light guide member 310 and the second light guide member 320 are made of materials having the same refractive index, for example, the same material.

FIG. 3 is an enlarged view of a part of the light guide body 300 including the second light guide member 320. As shown in FIG. 3, the second light guide member 320 has a parallel flat plate shape having end faces 321 on the proximal end side and the distal end side. The second light guide member 320 is joined to the light guide portion 302 of the first light guide member 310 with the intervening layer 400 interposed therebetween.

The intervening layer 400 interposed at the joint between the first light guide member 310 and the second light guide member 320 has a reflection and transmission film 401 and an adhesive layer 402.

The reflection-transmitting film 401 is formed on the second light guide member 320, for example, by vapor deposition. The reflection / transmission film 401 is, for example, a dielectric film, a metal film made of a silver material, or the like. The reflection transmission film 401 is a coating film having a half mirror characteristic, and a part of the light that guides the first light guide member 310 is transmitted to the second light guide member 320 side, and the other part is transmitted to the first light guide member 320 side. It is reflected on the member 310 side. The half mirror characteristic of the reflective transmissive film 401 may be a characteristic close to 50% reflectance / 50% transmittance, but is not limited to this, and may be, for example, 30% reflectance / 70% transmittance.

The adhesive layer 402 is a layer for joining the first light guide member 310 and the second light guide member 320, and is composed of, for example, an adhesive, and for example, the first light guide member 310 and the second light guide member. It has a refractive index similar to that of 320.

In the light guide body 300 configured as described above, since the second light guide member 320 has a parallel flat plate shape and is joined to at least the light guide portion 302 of the first light guide member 310, this is used. In the virtual image display device 1000, it is possible to suppress the loss of brightness of the observed virtual image and it is easy to manufacture.

Hereinafter, the effect of the light guide body 300 will be described in comparison with the light guide body according to the comparative embodiment. FIG. 4 is a configuration diagram of a virtual image display device including a light guide body according to a comparative form. The virtual image display device 1100 has a configuration in which the light guide body 300 in the virtual image display device 1000 is replaced with the light guide body 330. The light guide body 330 has a light ray incident portion 301, a light guide unit 302, an extraction unit 303, a light ray emitting unit 304, and a reflection unit 305, and has the same shape and the same shape as the first light guide member 310. Although it is made of a material, it does not have a second light guide member 320.

FIG. 5 is a diagram showing an example of light rays guided by the light guide body 330 according to the comparative form. The light ray R2 is a part of the image light emitted from a part of the image display element 100 shown in FIG. 4, and is incident on the surface of the light ray incident portion 301 at a certain angle. As shown in FIG. 4, the light beam R2 guides the light beam R2 while repeating total reflection in the light guide unit 302, but guides the light beam R2 without hitting the inclined surface 303b (see FIG. 2) in the extraction unit 303 even once. It reaches the tip of the light body 330. Since such a light ray R2 does not reach the user's eyes E, as a result, an image is missing, that is, a brightness loss is present in the virtual image visually recognized by the user, and the image quality of the virtual image is deteriorated.

On the other hand, FIG. 6 is a diagram showing an example of light rays guided by the light guide body 300 according to the first embodiment. The light ray R3 is a part of the image light emitted from a part of the image display element 100 shown in FIG. 1, and is incident on the surface of the light ray incident portion 301 at the same angle as the light ray R2 of FIG. In this case, as shown in FIG. 6, the light ray R3 is divided into light rays R4, R5, R6, and R7 due to the generation of multiple reflections due to the presence of the second light guide member 320. As a result, the apparent luminous flux inside the light guide 300 for the light beam R2 and thus for all image light can be expanded. As a result, for example, the light rays R6 reach the tip of the light guide body 330 without hitting the inclined surface 303b (see FIG. 2) in the extraction unit 303, but the rays R4 and R5 are emitted by the extraction unit 303. It is ejected from the ejection unit 304 to the outside and reaches the user's eye E. That is, the light beam R2 and thus the entire image light easily hit the inclined surface 303b in the extraction unit 303. Therefore, as compared with the case of FIG. 5, the loss of brightness in the virtual image visually recognized by the user is suppressed, so that the deterioration of the image quality of the virtual image is suppressed.

In FIG. 6, a light ray that reaches the end face 321 of the second light guide member 320 is generated like the light ray R7. On the other hand, the end face 321 may be coated to absorb light having a wavelength of image light, or the end face 321 may have a shape such as a ray R7 that emits incident light to the outside. .. As a result, it is suppressed that the reflected light from the end surface 321 of the light ray R7 guides the inside of the second light guide member 320 or the first light guide member 310 again. As a result, it is possible to prevent unnecessary light from being mixed into the virtual image as stray light and causing image deterioration. As the coating that absorbs light having a wavelength of image light, for example, a coating containing a material that absorbs visible light can be used. Further, the shape of emitting the incident light to the outside is formed by, for example, processing the end surface 321 into an uneven shape by rough surface processing or the like.

As described above, in the light guide body 300, since the second light guide member 320 has a parallel flat plate shape and is joined to at least the light guide portion 302 of the first light guide member 310, this is used. In the virtual image display device 1000, it is possible to suppress the loss of brightness of the observed virtual image. Further, such a parallel flat plate-shaped second light guide member 320 can be easily manufactured and prepared separately from the first light guide member 310, and further, it can be easily joined to the first light guide member 310. The light guide body 300 is easy to manufacture.

Further, since the light guide body 300 has the reflection transmission film 401, it becomes easy to control the introduction of image light to the second light guide member 320 and multiple reflections, and the apparent luminous flux can be further expanded.

Further, in the light guide body 300, it is desirable that the first light guide member 310 and the second light guide member 320 have the same refractive index. When made of a material having the same refractive index, a light beam that guides the first light guide member 310 and a light beam that is introduced from the first light guide member 310 to the second light guide member 320 and reflected to the first light guide member 320. It is possible to suppress the angular deviation from the light beam returning to 310, and enable good virtual image display. The refractive index is not completely the same, and the light beam that guides the first light guide member 310 and the first light guide member that is introduced from the first light guide member 310 to the second light guide member 320 and reflected to the first light guide member 320. The angle deviation from the light ray returning to 310 may have a difference that does not matter in the displayed virtual image.

Further, in the light guide body 300, the first light guide member 310 and the second light guide member 320 are formed by an adhesive layer 402 having a refractive index similar to that of the first light guide member 310 and the second light guide member 320. Since they are joined, it is possible to suppress an angle change when the light beam passes through the adhesive layer 402, and it is possible to display a good virtual image.

Further, in the light guide body 300, since the image light of substantially parallel light is incident on the light ray incident portion 301, the image light emitted from the light ray emitting portion 304 is likely to be imaged at one point on the retina of the user's eye. .. As a result, a good virtual image can be displayed even if the power of the image light is relatively weak.

(Second Embodiment)
FIG. 7 is a block diagram of the light guide body according to the second embodiment. The light guide body 300A can be used in place of the light guide body 300 in the virtual image display device 1000 shown in FIG. The light guide body 300A has a configuration in which the second light guide member 320 is replaced with the second light guide member 320A and the intervening layer 400 is replaced with the intervening layer 400A in the light guide body 300.

FIG. 8 is an enlarged view of a part of the light guide body 300A including the second light guide member 320A. As shown in FIGS. 7 and 8, the second light guide member 320A has a parallel flat plate shape and extends to the tip end side of the first light guide member 310. Regarding the intervening layer 400A, the reflective transmission film 401 is located at the position of the light guide portion 302 of the first light guide member 310, but does not extend to the positions of the take-out portion 303 and the light ray emitting portion 304. On the other hand, the adhesive layer 402A extends to the tip side of the first light guide member 310 and the second light guide member 320A, and joins the first light guide member 310 and the second light guide member 320A to the tip side. There is.

Similarly to the light guide body 300, the light guide body 300A configured in this way can suppress the loss of brightness of the observed virtual image and is easy to manufacture. Further, in the light guide body 300A, when the light emitting portion 304 of the first light guide member 310 is warped, the warp can be reduced by joining the second light guide member 320A, so that the distortion can be reduced. No good virtual image display is possible.

Further, in the light guide body 300A, since the reflection transmission film 401 does not extend to the light ray emitting portion 304, the light reflected by the reflection transmission film 401 may generate unnecessary light at the extraction portion 303 and become stray light. It is suppressed. As a result, deterioration of the image quality of the virtual image can be suppressed.

FIG. 9 is an enlarged view of a part of the light guide body according to the modified example of the second embodiment. In this light guide body, the adhesive layer 402 of the intervening layer 400 does not extend to the tip side of the first light guide member 310 and the second light guide member 320A, and the positions of the take-out portion 303 and the light ray emitting portion 304 and the positions thereof. On the tip side, the air layer 403 is interposed between the first light guide member 310 and the second light guide member 320A.

(Another configuration example of the first light guide body)
FIG. 10 is a diagram showing another configuration example of the first light guide member. The flatness of the surface 310Ba of the first light guide member 310B to be joined to the second light guide member 320 is low due to, for example, a manufacturing error. However, in the intervening layer 400B having the reflective transmission film 401 and the adhesive layer 402B, since the adhesive layer 402B has a refractive index similar to that of the first light guide member 310B, even if the flatness of the surface 310Ba is low, the first The consistency of the refractive index between the light guide member 310B and the second light guide member 320 is maintained, and a virtual image with good image quality can be obtained.

(Another configuration example of the take-out part)
FIG. 11 is a diagram showing another configuration example of the take-out unit. FIG. 11A shows the configuration of the take-out unit 303 having the surface 302a and the surface 303b shown in FIG. FIG. 11B shows the configuration of the take-out unit 303A having a configuration different from that of the take-out unit 303. The extraction unit 303A includes a plurality of surfaces 303a substantially parallel to the light ray emitting unit 304, a plurality of surfaces 303b inclined with respect to the light ray emitting unit 304, and a plurality of surfaces 303c inclined with respect to the light ray emitting unit 304. Have. The surface 303b and the surface 303c are inclined in different directions with respect to a plane that is perpendicular to the surface 303a and extends in the depth direction of the drawing. The surfaces 303a, 303c, and 303b are arranged alternately in the left-right direction of the drawing.

In the case of the extraction unit 303, in addition to the light ray R8 reflected by the surface 303b and directed to the light ray emitting unit 304, there may be a light ray R9 reflected by the surface 303a and further reflected by the surface 303b and directed to the light ray emitting unit 304. .. Such a ray R9 can be a stray light with respect to a virtual image.

On the other hand, in the case of the extraction unit 303A, the light ray R9 does not hit the surface 303b after being reflected by the surface 303a. The reason is that the next surface 303a is arranged at a position where the light ray R9 does not hit due to the presence of the surface 303c. As a result, the light ray R9 is less likely to become a stray light with respect to the virtual image, so that deterioration of the image quality of the virtual image is suppressed.

(Third Embodiment)
FIG. 12 is a block diagram of the light guide body according to the third embodiment. The light guide body 300B can be used in place of the light guide body 300 in the virtual image display device 1000 shown in FIG. The light guide body 300B has a configuration in which the take-out unit 303 is replaced with the take-out unit 303B in the light guide body 300.

The take-out unit 303B is formed by arranging a number of mirrors provided in the first light guide member 310 and coated with a specific reflectance. Similar to the light guide body 300, such a light guide body 300B can suppress the loss of brightness of the observed virtual image and is easy to manufacture.

(Fourth Embodiment)
FIG. 13 is a block diagram of the light guide body according to the fourth embodiment. The light guide body 300C can be used in place of the light guide body 300 in the virtual image display device 1000 shown in FIG. The light guide body 300C has a configuration in which the take-out unit 303 is replaced with the take-out unit 303C in the light guide body 300.

The take-out portion 303C is formed by providing a microstructure and a gap zone on the surface of the first light guide member 310 on the side opposite to the light ray emitting portion 304. Similar to the light guide body 300, such a light guide body 300C can suppress the loss of brightness of the observed virtual image and is easy to manufacture.

(Example, comparative example)
As an example, the brightness distribution of the virtual image in the virtual image display device having the configuration shown in FIG. 1 was simulated and calculated under the following conditions. Further, as a comparative example, the brightness distribution of the virtual image in the virtual image display device having the configuration shown in FIG. 4 was simulated and calculated under the following conditions. However, in the comparative example, since the second light guide member 320 does not exist, the condition does not apply.

<Conditions>
Image display element 100
-Display area: 5.28 mm x 2.97 mm
Optical system 200
・ Viewing angle (diagonal): 40 degrees ・ Focal length: 6.8 mm
・ FNO. : 5.8
Second light guide member 320
・ Material: PMMA
・ Size: 15mm x 21mm
・ Wall thickness: 0.7 mm
First light guide member 310
・ Material: PMMA
・ Thickness: Thinnest part 0.5 mm, thickest part 2 mm
・ Length: 59mm
・ Width: 50 mm
Extraction unit 303
-Width of surface 303b: 0.2 mm, angle with respect to light emitting portion 304: 27 degrees-Width of surface 303a: 0.76 mm
Eye box: 5 mm or more Eye relief: 15 mm or more

FIG. 14 is a diagram showing the result of simulation calculation of the brightness distribution of the virtual image in the virtual image display device of the comparative example. FIG. 15 is a diagram showing the result of simulation calculation of the brightness distribution of the virtual image in the virtual image display device of the embodiment. In FIGS. 14 and 15, the X direction indicates the longitudinal direction of the light guide (the left-right direction in the drawings in FIGS. 1 and 4), and the Y direction indicates the width direction of the light guide (the depth direction in the drawings in FIGS. 1 and 4). Shown. Numerical values in the X and Y directions indicate relative positions, and zero indicates the center position.

In the comparative example of FIG. 14, there was a large luminance loss at positions P1, P2, and P3 separated in the X direction so that the brightness was close to 0, but in the embodiment of FIG. 15, such a large luminance loss was present. It didn't exist.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications or modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

For example, the optical system 200 may be configured to once form an intermediate image of the image light emitted from the image display element 100, then generate substantially collimator light, and incident the light guide body 300. By forming the intermediate image once in this way, the heavy image display element 100 can be arranged behind (the side away from the light guide 300) in the virtual image display device 1000, so that the virtual image display device 1000 is made into a glasses type. In some cases, it is possible to realize a glasses-type virtual image display device, which is also called a smart glass, which can reduce the front weight and is comfortable to wear.

Further, the first light guide member 310 and the second light guide member 320 are examples of two light guide members constituting the light guide body, but the light guide body is composed of two or more light guide members. May be good.

Further, the second light guide member 320 is joined to the main surface of the light guide portion 302 on the same side as the light ray emitting portion 304 in the first light guide member 310, but the light guide portion on the same side as the take-out portion 303. It may be joined to the main surface of 302.

Further, the reflective transmission film 401 is not limited to being formed on the second light guide member 320, and may be formed on the first light guide member 310, for example, by thin film deposition.

Further, the configuration of the light guide body and the virtual image display device described above is also established as a structure in which the left and right sides of the drawing are reversed. Further, the virtual image display device may be configured to observe one light guide body with both eyes, may be configured to observe two light guide bodies with each eye, or one light guide body may be observed by one eye. It may be configured as a small monocular observation method for visual observation. In this way, it is possible to realize a lightweight smart glass that does not lose brightness even when displaying a wide-angle virtual image of 30 degrees or more, for example. Further, the virtual image display device may be configured as a head-up display (HUD).

100: Image display element 200: Optical system 300: Light guide body 301: Light ray incident part 302: Light guide part 303: Extraction part 304: Light ray emitting part 310: First light guide member 320: Second light guide member 321: End face 401: Reflective transmission film 402: Adhesive layer 1000: Virtual image display device

Japanese Patent No. 5698297 Japanese Patent No. 5421185 Japanese Patent No. 5703875 U.S. Patent Publication No. 2017/0285346

Claims (8)

A light guide that guides and emits light.
It is composed of two or more light guide members including a first light guide member and a second light guide member.
The light beam incident part, which is the surface on which the light is incident,
A light guide unit that repeatedly reflects and guides the light incident from the light ray incident portion, and a light guide unit.
A light emitting portion that emits the light to the outside of the light guide body,
A take-out unit that reflects the light guided by the light guide unit toward the light ray emitting unit, and a take-out unit.
Have,
The second light guide member has a parallel flat plate shape, and is at least a light guide body joined to the light guide portion of the first light guide member. A part of the light that is interposed at the joint between the first light guide member and the second light guide member and guides the first light guide member is transmitted to the second light guide member side, and the other portion is transmitted. The light guide body according to claim 1, which has a reflective and transmissive film that reflects light toward the first light guide member. The light guide body according to claim 1 or 2, wherein the first light guide member and the second light guide member are made of a material having the same refractive index. The third aspect of the present invention, wherein the first light guide member and the second light guide member are joined by an adhesive layer having the same refractive index as the first light guide member and the second light guide member. Light guide body. The light guide body according to any one of claims 1 to 4, which has a coating on the end surface of the second light guide member that absorbs light having the wavelength of the light. The light guide body according to any one of claims 1 to 4, wherein the end face of the second light guide member has a shape of emitting incident light to the outside. The light guide according to any one of claims 1 to 6, wherein the light ray incident portion is incident with the light of substantially parallel light. Image display element and
The light guide according to any one of claims 1 to 7, wherein the image light emitted from the image display element is guided and emitted to form a virtual image.
An optical system that causes the image light emitted from the image display element to enter the light beam incident portion of the light guide body, and an optical system.
A virtual image display device comprising.

Images