JP2022020912A - Light guide member and display unit - Google Patents

Abstract

To provide a light guide member and a display unit that have reduced stray light while achieving a wide viewing angle.SOLUTION: A light guide member 300 has: a light beam emitting unit 304 that reflects guided image light and emits the image light to the outside; a second surface 306 that is parallel and opposite to the light beam emitting unit 304; a first surface 305 that is inclined in a direction in which the image light is guided so that the distance between the light beam emitting unit 304 and the first surface is reduced; and a third surface 307 that is provided between the second surface 306 and the first surface 305 and inclined in the direction in which the image light is guided so that the distance between the light beam emitting unit 304 and the third surface is increased. When the angle formed by the third surface 307 with respect to the light beam emitting unit 304 is α, and the minimum value of the reflection angle θ of the image light with respect to the light beam emitting unit 304 is θ1, α≥90°-θ1 is satisfied.SELECTED DRAWING: Figure 5

Description

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

In Patent Document 1, the light incident portion that captures the image light inside and the first and second total reflecting surfaces extending opposite to each other are provided, and the image light captured from the light incident portion is the first and second total. The image extraction unit includes a light guide unit that is guided by total reflection on the reflection surface and a light emission unit having an image extraction unit that enables image light incident through the light guide unit to be extracted to the outside by bending an optical path. In order to reflect the image light guided by the light guide unit, a plurality of second units extending so as to incline toward the inside of the light guide unit at the back side of the light guide unit with respect to the light guide direction with respect to the second total reflecting surface. Disclosed is a light guide plate in which one element surface and a plurality of second element surfaces extending at an blunt angle with respect to the first element surface are alternately arranged.

An object of the present invention is to provide a light guide member and a display device that reduce stray light while realizing a wide viewing angle.

A first aspect of the present invention is an interface that reflects guided image light and emits it to the outside.
Provided between the facing surface parallel to the interface, the first inclined surface inclined so that the distance from the interface is reduced in the direction in which the image light is guided, and the facing surface and the first inclined surface. It has a second inclined surface that is inclined so that the distance from the interface is large in the direction in which the image light is guided, and the angle formed by the second inclined surface with respect to the interface is α, with respect to the interface of the image light. Assuming that the minimum value of the reflection angle θ is θ1, the light guide member satisfies α ≧ 90 ° −θ1.

According to the present invention, it is possible to provide a light guide member and a display device that reduce stray light while realizing a wide viewing angle.

It is a figure which shows an example of the light guide member 300 which concerns on embodiment of this invention, and the virtual image display device 1000 which used the light guide member 300. It is a figure which showed the state that the light propagating in the light guide member 300 which concerns on this embodiment is emitted. It is a figure which shows the light propagating in the light guide member 300 which concerns on this embodiment. It is an enlarged view of the image extraction part 303 in the light guide member 300 which concerns on this embodiment. It is a figure which shows the length l, the inclination angle γ, the length X1, and the inclination angle α in FIG. 4B. FIG. 4B is a diagram showing light 201 propagating at the minimum value θ1 of the reflection angle θ in FIG. 4B. It is a figure which shows the modification of the light guide member 300 which concerns on this embodiment. It is a figure which shows the 2nd modification of the light guide member 300 which concerns on this embodiment. It is a figure which shows the comparative example of the light guide member 300 which concerns on this embodiment. It is a figure which shows the 3rd modification of the light guide member 300 which concerns on this embodiment. It is a figure which showed the detail of the light guide member 300 which concerns on the 3rd modification shown in FIG. It is a figure which shows the optical system layout of the virtual image display device 1000 which concerns on this embodiment. FIG. 12 is an enlarged view of an image extraction unit 303 of the virtual image display device 1000 shown in FIG. It is a figure which simulated the state of the luminance distribution of the virtual image in the virtual image display device 1000 which concerns on this embodiment. It is a figure which simulated the state of the luminance distribution of a virtual image in the comparative example of the virtual image display device 1000 which concerns on this embodiment. It is a figure which shows the use state of various examples of the virtual image display device 1000 which concerns on this embodiment.

FIG. 1 is a diagram showing an example of a light guide member 300 according to an embodiment of the present invention and a virtual image display device 1000 using the light guide member 300.

The virtual image display device 1000 is an example of a display device, and is an image display element 100 that outputs image light of a display image, an optical system 200 that collimates and emits image light from the image display element 100, and a light guide member 300. Is provided as a virtual image display optical system.

The image display element 100 is a device that outputs the image light of the display image that is the basis of the virtual image displayed through the light guide member 300. As the image display element 100, an organic LED (OLED: Organic Light Emitting Diode) or a transmissive liquid crystal display element is suitable, but other display methods can be applied. For example, as the image display element 100, a DMD (Digital Micromirror Device) can be applied. Further, as the image display element 100, a TFT (Thin Film Transistor) or LCOS (Liquid Crystal On Silicon) can be applied. Further, as the image display element 100, MEMS (Micro Electro Electro Mechanical Systems) can be applied.

When an LCOS, DMD, or the like that requires a light source is used, the image display element 100 includes a light source for emitting illumination light to illuminate the image display surface of the image display element 100. Various light sources can be applied, and for example, an LED (Light Emitting Diode), a semiconductor laser (Laser Diode: LD), a discharge lamp, or the like can be used.

The optical system 200 is composed of a plurality of optical lenses, diaphragms, and the like, and emits image light output from the image display element 100 as parallel light.

The light guide member 300 includes a light incident unit 301, a light guide unit 302, an image extraction unit 303, and a light ray emission unit 304. The light ray emitting unit 304 is an example of an interface (boundary surface) that reflects the guided image light and emits it to the outside.

FIG. 1 shows an optical path diagram of the center of an image display element 100 corresponding to a horizontal virtual image display. The image light emitted from the center of the image display element 100 is converted into angle information by the optical system 200 having a collimating optical system function, and the position information of the image display element 100 is converted into angle information from the light incident portion 301 into the light guide member 300. Incident.

Then, the light that has entered the light guide member 300 propagates while repeating total reflection at the light guide unit 302.

Then, when the light hits the image extraction unit 303, the light is emitted from the light ray emitting unit 304, and the light enters the user's eyes. The user can visually recognize the virtual image of the image light by looking forward through the light ray emitting portion 304 of the light guide member 300.

FIG. 2 is a diagram showing how the light propagating in the light guide member 300 according to the present embodiment is emitted.

As shown in FIG. 2, the image extraction unit 303 includes at least a plurality of first surface 305 and second surface 306, respectively.

The first surface 305 is an example of a first inclined surface that is inclined so that the distance from the light ray emitting portion 304 is reduced in the direction in which the image light is guided, and the second surface 306 is the light ray emitting portion 304. This is an example of a facing surface that is parallel to and faces the light emitting portion 304.

When the light propagated while repeating total reflection by the light guide unit 302 hits the first surface 305, it is emitted from the light ray emitting unit 304 and reaches the eyes. Further, by providing the second surface 306, it is possible to proceed toward the back of the light guide member 300 until it hits the first surface 305, and the light is guided toward the light ray emitting portion 304 even at the back of the light guide member 300. be able to. By doing so, it is possible to realize a virtual image display device 1000 capable of wide-angle display even if the light guide member 300 is thin.

FIG. 3 is a diagram showing light propagating in the light guide member 300 according to the present embodiment.

FIG. 3 shows the light 201 propagating at the angle θ1 having the smallest reflection angle with respect to the light ray emitting portion 304 among the light propagated by total internal reflection on the upper surface 308 and the lower surface 309 of the light guide portion 302 of the light guide member 300. The light 202 propagating at the largest angle θ2 is shown, and the light from the pixels at both ends of the image display element 100 in the paper surface of FIG. 3 is shown. That is, the viewing angle can be widened as θ1 becomes smaller and θ2 becomes larger.

FIG. 4 is an enlarged view of the image extraction unit 303 in the light guide member 300 according to the present embodiment.

FIG. 4A is an enlarged view of the image extraction unit 303 according to the comparative example, and in FIG. 4B, a third surface newly inclined in a direction different from that of the first surface 305 with respect to FIG. 4A. 307 is provided. The third surface 307 is provided between the first surface 305 and the second surface 306, and is inclined so that the distance from the light emitting portion 304 increases in the direction in which the image light is guided. This is an example.

The light shown by the solid line and the dotted line in FIGS. 4A and 4B is light emitted from the same pixel of the image display element 100, and is a light guide member at the same angle by the optical system 200 having a collimating optical system function. Propagate within 300.

At this time, the light shown by the dotted line in FIG. 4A directly hits the first surface 305 and travels in the direction of the light emitting portion 304 after being reflected by the second surface 306, whereas in FIG. 4B, the light is the first. By providing the three surfaces 307, it is possible to prevent the first surface 305 from being directly exposed to light after being reflected by the second surface 306.

As a result, of the light propagating in the light guide member 300 by total internal reflection, only the light totally reflected by the lower surface of the light guide member 300 can be applied to the first surface 305.

By doing so, in FIG. 4A according to the comparative example, the stray light generated by the light in both directions of the light totally reflected by the upper surface and the lower surface of the light guide member 300 hitting the first surface 305 is prevented. be able to.

FIG. 5 is a diagram showing a length l, an inclination angle γ, a length X1, and an inclination angle α in FIG. 4B.

FIG. 5 shows the length of the first surface 305 and the surface 307 of the image extraction unit 303 and the angle with respect to the light ray emitting unit 304 in the same cross section, and 201 is the light propagating in the light guide member 300 by total internal reflection. , Shows the light propagating at the angle θ1 with the smallest reflection angle. Here, when the light reflected by the lower surface 309 of the light guide member hits the surface 307, the angle changes and becomes stray light. Therefore, it is necessary to prevent the light 201 propagating at the angle θ1 having the smallest reflection angle from hitting the surface 307. Yes, it is possible to prevent stray light from being generated by setting the angle α of the surface 307 with respect to the light beam emitting portion 304 to α ≧ 90 ° −θ1 in the same cross section. Further, it is possible to realize a wide viewing angle by reducing θ1.

Further, among the light propagating in the light guide member 300 by total reflection, the light 202 propagating at the angle θ2 having the largest reflection angle is originally the light totally reflected by the lower surface 309 of the light guide member 300. The light reflected by the surface 305 and emitted from the light emitting unit 304 is observed as an image.

However, when the light totally reflected by the upper surface 308 of the light guide member 300 directly hits the first surface 305, the angle of the light emitted from the light ray emitting unit 304 changes, resulting in stray light.

Therefore, when the length of the first surface 305 is l, the first surface 305 is moved upward by the length of X1 so that the light totally reflected by the upper surface 308 of the light guide member 300 does not directly hit the first surface 305. It is necessary to arrange it so that it does not hit.

At this time, assuming β = 90 ° −θ2, X1> l (| tan (γ) |-| tan (β) |) / (| tan (α) | + | tan (β) |) in the same cross section. By setting | cos (γ) / cos (α) |, it is possible to prevent the light totally reflected by the upper surface 308 of the light guide member 300 from directly hitting the first surface 305, and it is possible to prevent stray light. .. Further, it is possible to realize a wide viewing angle by increasing θ2.

FIG. 6 is a diagram showing light 201 propagating at the minimum value θ1 of the reflection angle θ in FIG. 4 (b).

FIG. 6 is an enlarged view of the image extraction unit 303. For example, when the light guide member 300 is manufactured by molding, the region X3 in FIG. 6 may have a shape error due to a molding defect. The value of X3 may be on the order of several μm.

If the X3 portion is exposed to light, the traveling direction of the light is disturbed, resulting in stray light or flare, which impairs the image quality. Therefore, it is necessary to further increase α shown in FIG. 5 so that the light 201 propagating at the angle θ1 having the smallest reflection angle does not hit the portion of X3 in the first surface 305. By doing so, the light does not hit the X3 portion, and a good image without stray light or flare can be observed. By increasing α, a good image with a wide viewing angle and no stray light can be observed, but α is preferably less than 90 ° (α <90 °). As a result, the light guide plate can be efficiently manufactured by resin molding.

FIG. 7 is a diagram showing a modified example of the light guide member 300 according to the present embodiment.

FIG. 7 is a diagram in which a reflection coat is applied to the first surface 305 of the image extraction unit 303. The light propagating in the light guide member 300 by total internal reflection is reflected when it hits the first surface 305 to which the reflection coating is applied, and heads toward the light ray emitting portion 304. Then, the light emitted from the light ray emitting unit 304 enters the eyes and is observed as a virtual image. At this time, by not applying the reflection coating to the second surface 306, the outside world can be seen through the light guide member 300, and the image can be superimposed on the real world.

FIG. 8 is a diagram showing a second modification of the light guide member 300 according to the present embodiment.

FIG. 8 is a diagram in which the first surface 305, the second surface 306, and the third surface 307 of the image extraction unit 303 are all coated with a coat 402 having a reflection transmission function. As shown in FIG. 8, since the coat 402 having the reflection transmission function is also attached to the second surface 306, the transmittance when looking at the outside world decreases, but the first surface 305, the second surface 306, and the third surface By coating all 307 at once, the manufacturability at the time of film formation becomes easy.

FIG. 9 is a diagram showing a comparative example of the light guide member 300 according to the present embodiment.

FIG. 9 shows a state in which light emitted from one pixel on the image display element 100 travels through the light guide member 300 of FIG. As shown in FIG. 9, the light incident on the light guide member 300 from the light ray incident portion 301 propagates while repeating total reflection in the light guide member 300, but depending on the propagation angle in the light guide member 300. The inclined first surface 305 in the image extraction unit 303 may not be exposed to light, or even if it is exposed, it may not reach the eyes as shown in FIG. In such a case, the image is chipped in the image and the image quality is deteriorated.

FIG. 10 is a diagram showing a third modification of the light guide member 300 according to the present embodiment.

FIG. 10 is a diagram in which a member 310 having a parallel plane newly joined to the light guide member 300 with respect to FIG. A coat 403 having reflection and transmission characteristics is applied to the surface side of the parallel plane member 310 to which the light guide member 300 is joined.

In FIG. 10, the parallel plane member 310 is joined to the upper surface 308 of the light guide member 300, but it may be joined to the lower surface 309. Similar to FIG. 9, the light emitted from one pixel on the image display element 100 travels through the light guide member 300, but unlike FIG. 9, in FIG. 10, the light is parallel to the light guide member 300. It can be seen that the light is reflected and multiple-reflected by the coat 403 having the transmission characteristic between the members 310, and the apparent light rays in the light guide member 300 are increased as compared with FIG.

By doing so, the frequency of hitting the inclined first surface 305 in the image extraction unit 303 becomes higher than that in FIG. 9, and the light easily reaches the eyes, so that the image is not chipped and a good image can be observed. can.

FIG. 11 is a diagram showing details of the light guide member 300 according to the third modification shown in FIG. FIG. 11 is a diagram showing a state of joining the light guide member 300 and the member 310 on a parallel plane. In FIG. 11, the parallel plane member 310 is coated with a coat 403 having reflection and transmission characteristics, and is joined to the upper surface 308 of the light guide member 300 via the adhesive layer 404, but is reflected by the light guide member 300. A parallel plane member 310 may be joined via the adhesive layer 404 after applying a coat 403 having a transmission property.

The coating 403 having reflection and transmission characteristics is, for example, coated with half mirror characteristics, and a dielectric film or a metal coating such as silver or aluminum is applied. The half mirror characteristic of the coat 403 having the reflection and transmittance characteristics is not limited to the characteristics having a reflectance of 50% / transmittance of 50%, and may be, for example, a reflectance of 30% / a transmittance of 70%. Further, it is desirable that the adhesive layer 404 is made of a material having a refractive index similar to that of the light guide member 300 and the parallel plane member 310.

By doing so, it is possible to eliminate the angular deviation of the light rays in the adhesive layer 404. Further, the ends 311 and 312 of the parallel plane member 310 are formed of a paint that absorbs light or a shape that transmits light so that the light reflected by the ends 311 and 312 does not propagate in the light guide member 300 again. Is desirable. By doing so, it is possible to prevent unnecessary light from entering the image.

FIG. 12 is a diagram showing an optical system layout of the virtual image display device 1000 according to the present embodiment.
Example: FIG. 12
■ Virtual image display device 1000
Viewing angle (diagonal): 40 degrees ■ Image display element 100
Display area: 5.0 mm x 3.1 mm
■ Light guide member 300
-Material: Zeonex E48R
・ Thickness: Thinnest part 1.2 mm, thickest part 2.5 mm
・ Length: 59mm
・ Width: 50 mm
-Image extraction unit (103)
First surface 305: l = 0.23 mm, X2 = 3.2 μm, γ = 28 °
-Length of the second surface 306: 0.492 to 0.717 mm
Third surface 307: X1 = 0.038 mm, α = 52 °
-Assumed value of propagation angle: θ1 = 42.8 °, θ2 = 69.2 °
・ Eye box: 5 mm or more in the horizontal direction ・ Eye relief: 15 mm or more ■ Parallel flat plate member 310
・ 14.8 mm x 21 mm x 0.6 mm
・ Material: PMMA

The optical system 200 of FIG. 12 once creates an intermediate image of the light emitted from the image display element 100, then generates substantially collimator light, and causes the light to be incident on the light guide member 300. By once creating the intermediate image in this way, the heavy image display element 100 can be arranged behind, so that when the virtual image display device 1000 is a glasses type, the front weight can be reduced and the glasses type virtual image is comfortable to wear. A display device can be realized.

Of course, light may be directly incident on the light guide member 300 by an optical system 200 that generates substantially collimator light from the image display element 100 as shown in FIG. 1 without forming an intermediate image. The light guide member 300 of FIG. 12 has the shape shown in FIG. 10, and a member 310 having a parallel plane is joined to the light guide member 300. FIG. 12 shows how the light emitted from both ends of the image display element 100 enters the eyes after being incident on the light guide member 300 via the optical system 200.

FIG. 13 is an enlarged view of the image extraction unit 303 of the virtual image display device 1000 shown in FIG.

13 (a) is an enlarged view of the image extraction unit 303 of the light guide member 300, and FIG. 13 (b) is an enlarged view of the first surface 305, the second surface 306, and the third surface 307 of one element. be. In this embodiment, the elements of FIG. 13B are composed of 17, but this number may be changed by setting the horizontal viewing angle and the visible range (eye box) even if the eyes are moved.

Further, there are 16 second surfaces 306 between the first surface 305 and the next surface 307 in the present invention, but the length of each is longer according to the traveling direction of the light in the light guide member 300. By doing so, the amount of light that hits the first surface 305 can be controlled, and unevenness in resolution in the image can be reduced.

FIG. 14 is a diagram simulating the state of the luminance distribution of the virtual image in the virtual image display device 1000 according to the present embodiment.

Specifically, FIG. 14 is a result of simulating the state of the luminance distribution of the virtual image in this embodiment shown in FIG.

FIG. 15 is a diagram simulating the state of the luminance distribution of the virtual image in the comparative example of the virtual image display device 1000 according to the present embodiment.

Specifically, FIG. 15 is a result of simulating the state of the luminance distribution of the virtual image when the members 310 on the parallel plane are not joined in the embodiment shown in FIG. In FIG. 15, a black portion having low luminance is conspicuous in the luminance distribution of the virtual image, but in FIG. 14, it can be seen that the portion that looks black is reduced and the luminance unevenness is improved.

Of course, FIGS. 1 to 15 are established even if the left and right sides are reversed. It is also possible to check one light guide member with both eyes, divide it into two and see it with each eye, or make it smaller and monocular.

In the embodiment shown in FIGS. 1 to 15 described above, an example is described in which the light ray incident portion 301 of the light guide member 300 is arranged on the left side of the virtual image observer and the image light is incident from the left side of the virtual image observer. The same effect as described above can be obtained when the arrangement is reversed left and right, that is, when the light ray incident portion 301 of the light guide member 300 is arranged on the right side of the virtual image observer and the image light is incident on the right side of the virtual image observer. can get.

FIG. 16 is a diagram showing a usage state of various examples of the virtual image display device 1000 according to the present embodiment.
16 (a), (b) and (c) exemplify a case where the light guide member 300 is applied to a spectacle-type virtual image display device, that is, an HMD.

The example shown in FIG. 16A is a case where one light guide member 300 is applied to an HMD for both eyes, and the light incident portion 301 of the light guide member 300 and the image light incident from the light ray incident portion 301 are combined. A mirror 350 that guides light inside the light guide member 300 is arranged on the right side of the virtual image observer, that is, the user. The light guide member 300 is fixed to a frame portion 500 that serves as a vine to be hung on the user's ear. Although the frame portion is simplified in FIG. 26, the frame portion 500 may have a shape that covers not only both ends of the light guide member 300 but also the upper edge and the lower edge.

On the other hand, the examples shown in FIGS. 16 (b) and 16 (c) are cases where one light guide member 300 is miniaturized and applied to the HMD. The example shown in FIG. 16B is a case where two light guide members 300 are arranged as HMDs for both eyes so as to correspond to the positions of the left and right eyes of the user, and the light incident portion of each light guide member 300. 8 is arranged on the left and right outer sides. Further, FIG. 16C shows a case where one light guide member 300 is arranged as an HMD for a monocular so as to correspond to the position of either the left or right eye of the user.

Although the virtual image optical system and the light source are not shown in FIG. 16, they can be attached to the frame portion 500. That is, in the examples shown in FIGS. 16A and 16C, the light source 52, the image display element 100, and the optical system 200 are placed in the frame portion on the right eye side, and in the example shown in FIG. 16B, these are placed in both the left and right frame portions. It can be attached to.

In the example shown in FIG. 16, a case where the light guide member 300 is applied to the spectacle-shaped HMD has been described. Further, the light guide member 300 of each of the above-described embodiments can be applied to other types of HMDs, and further can be applied to a head-up display (HUD). The light guide member of each embodiment is particularly suitable for displaying an original image formed by a light flux light-modulated by a micro device.

As described above, the light guide member 300 can be attached to a person's face like glasses. Then, when the image light of the image display element or the like is collimated and incident from the light ray incident portion 301, the image of the image display element or the like can be observed as a virtual image as described above. Since the light guide member 300 is a transparent body, it is possible to observe the surrounding scene together with the above image.

● Summary ●
As described above, the light guide member 300 according to the embodiment of the present invention has a light beam emitting unit 304 which is an example of an interface (boundary surface) that reflects the guided image light and emits light to the outside. An example of a second surface 306 which is an example of a facing surface parallel to the light emitting portion 304 and a first inclined surface which is inclined so that the distance from the interface becomes smaller in the direction in which the image light is guided. An example of a second inclined surface provided between a first surface 305 and the second surface 306 and the first surface 305 and inclined so as to increase the distance from the interface in the direction in which the image light is guided. If the third surface 307 is provided, the angle formed by the third surface 307 with respect to the light emitting portion 304 is α, and the minimum value of the reflection angle θ with respect to the light emitting portion 304 of the image light is θ1, α ≧ 90 ° −θ1. Meet.

The light guide member 300 is provided with a third surface 307 between the second surface 306 and the first surface 305, which is inclined so as to increase the distance from the interface in the direction in which the image light is guided. It is possible to reduce that the image light reflected by the two surfaces 306 is re-reflected by the first surface 305 and becomes stray light.

Further, the light guide member 300 has α ≧ 90 ° −θ1 when the angle formed by the third surface 307 with respect to the light ray emitting portion 304 is α and the minimum value of the reflection angle θ with respect to the light ray emitting portion 304 of the image light is θ1. By satisfying the above conditions, it is possible to reduce that the image light reflected by the light ray emitting unit 304 is reflected by the third surface 307 and becomes stray light.

That is, the light guide member 300 realizes a wide viewing angle by reducing the minimum value θ1 of the reflection angle θ with respect to the light ray emitting portion 304 of the image light, and re-reflects by the first surface 305 and reflects by the third surface 307. It is possible to reduce stray light caused by.

The light guide member 300 according to the present embodiment reflects the guided image light and emits the (boundary) light ray emitting portion 304 to the outside, the second surface 306 facing the light ray emitting portion 304, and the image light. Is provided between the first surface 305 and the second surface 306 and the first surface 305, which are inclined so as to reduce the distance from the interface in the direction in which the light is guided, and in the direction in which the image light is guided. It has a third surface 307 that is inclined so that the distance from the interface is large, the angle formed by the first surface 305 with respect to the light ray emitting portion 304 is γ, and the maximum value of the reflection angle θ with respect to the light ray emitting portion 304 of the image light is θ2. When the length of the first surface 305 is l and the length of the third surface 307 is X1 and β = 90 ° −θ2, X1> l (| tan (γ) |-| tan (β) |) / (| Tan (α) | + | tan (β) |) · | cos (γ) / cos (α) | is satisfied.

As a result, in the light guide member 300, the light guide member 300 increases the maximum value θ2 of the reflection angle θ with respect to the light ray emitting portion 304 of the image light to realize a wide viewing angle, and the image reflected by the second surface 306. It is possible to surely reduce the fact that the light is re-reflected on the first surface 305 and becomes stray light.

When the intersection of the first surface 305 and the third surface 307 is P1 and the intersection of the third surface 307 and the second surface 306 is P2, the light guide member 300 has a reflection angle θ with respect to the light ray emitting portion 304 of the image light. Ξ = α + θ1-90 ° when the intersection of the image light guided by the minimum value θ1 of is P3 and the intersection with the first surface 305 when passing near P2 is P3 and X2 is the distance between P1 and P3. , Η = α + γ-ξ, X2 = X1 (sin (ξ) / sin (η)) X2 is a region that is guided through the light guide member 300 and is not exposed to the image light.

As a result, the light guide member 300 is provided with a region on the first surface 305 where the image light guided inside the light guide member 300 does not hit, so that the light does not hit the shape error portion due to molding defects or the like. It is possible to prevent stray light and flare, so that a good image can be provided.

A plurality of the second surface 306, the third surface 307, and the first surface 305 are repeatedly arranged so as to approach the light ray emitting portion 304 in the direction in which the image light is guided. As a result, even when the viewing angle is wide, the image light guided in the light guide member 300 easily hits the first surface 305, and a good image with little luminance unevenness can be provided.

The lengths of the plurality of second surfaces 306 are different from each other. As a result, the light guide member 300 can control the amount of light that hits the first surface 305 by making the length of the second surface 306 different, so that unevenness of resolution in the image can be reduced and a good image can be obtained. Can be provided.

The light guide member 300 has a reflection coat 401 on the first surface 305. As a result, the light guide member 300 can efficiently guide the image light toward the light ray emitting unit 304 when the image light propagating in the light guide member 300 hits the first surface 305, and a good image can be obtained. Can be provided.

The light guide member 300 has a coat 402 having reflection and transmission characteristics on the first surface 305, the second surface 306, and the third surface 307. As a result, the light guide member 300 can simplify the coating vapor deposition process while ensuring see-through property for seeing the outside world.

The light guide member 300 has two parallel planes 308 and 309 that guide the image light by repeating total reflection, and the parallel plane member 310 is joined to at least one of the two planes 308 and 309. The joint portion of the member 310 on the parallel plane has a coat 403 having reflection and transmission characteristics. As a result, the light guide member 300 can provide a good image without image omission by multiple-reflecting light in the member 310 of the parallel flat plate.

The virtual image display device 1000 according to an embodiment of the present invention comprises an image display element 100, the above-mentioned light guide member 300 that guides and emits image light emitted from the image display element 100, and an image display element 100. It includes an optical system 200 that causes the emitted image light to enter the light guide member 300.

That is, the virtual image display device 1000 realizes a wide viewing angle by reducing the minimum value θ1 of the reflection angle θ with respect to the light ray emitting portion 304 of the image light, and re-reflects by the first surface 305 and reflects by the third surface 307. Since the stray light caused by the above can be reduced, a good image can be provided.

100 Image display element 200 Optical system 201 Light propagating at the minimum value θ1 of the reflection angle θ with respect to the light emitting part 304 202 Light propagating at the maximum value θ2 of the reflection angle θ with respect to the light emitting part 304 300 Light guide member 301 Light emitting part 302 Light guide part 303 Image extraction part 304 Light ray emission part (intersection, boundary surface)
305 First surface (first inclined surface)
306 Second surface (opposing surface)
307 Third surface (second inclined surface)
308 Upper surface of the light guide unit 302 309 Lower surface of the light guide unit 302 310 Parallel plane member 311 One end of the parallel plane member 310 312 The other end of the parallel plane member 310 350 Mirror 401 Reflection coat 402 Reflection and transmission characteristics Coat 403 Coat 404 with reflection and transmission characteristics Adhesive layer 500 Frame part 1000 Virtual image display device (display device)

Japanese Patent No. 5703875

Claims (9)

The interface that reflects the guided image light and emits it to the outside,
With the facing surface parallel to the interface,
A first inclined surface that is inclined so that the distance from the interface becomes small in the direction in which the image light is guided.
It has a second inclined surface provided between the facing surface and the first inclined surface and inclined so that the distance from the interface becomes large in the direction in which the image light is guided.
Let α be the angle formed by the second inclined surface with respect to the interface, and θ1 be the minimum value of the reflection angle θ of the image light with respect to the interface.
α ≧ 90 ° −θ1
A light guide member that meets the requirements. The angle formed by the first inclined surface with respect to the interface is γ, the maximum value of the reflection angle θ of the image light with respect to the interface is θ2, the length of the first inclined surface is l, and the second inclined surface has a length of l. Assuming that the length is X1 and β = 90 ° -θ2,
X1> l (| tan (γ) |-| tan (β) |) / (| tan (α) | + | tan (β) |) · | cos (γ) / cos (α) |
The light guide member according to claim 1. When the intersection of the first inclined surface and the second inclined surface is P1 and the intersection of the second inclined surface and the facing surface is P2, the minimum reflection angle θ of the image light with respect to the interface is the minimum. When the intersection of the image light guided by the value θ1 with the first inclined surface when passing near P2 is P3 and X2 is the distance between P1 and P3,
ξ = α + θ1-90 °
η = α + γ-ξ
X2 = X1 (sin (ξ) / sin (η))
The light guide member according to claim 1 or 2, wherein X2 defined in the above is a region that is guided in the light guide member and is not exposed to the image light. One of claims 1 to 3, wherein a plurality of the facing surface, the second inclined surface, and the first inclined surface are repeatedly arranged so as to approach the interface in the direction in which the image light is guided. The light guide member described. The light guide member according to any one of claims 1 to 4, wherein the plurality of facing surfaces have different lengths from each other. The light guide member according to any one of claims 1 to 5, wherein the first inclined surface has a reflective coat. The light guide member according to any one of claims 1 to 5, wherein the first inclined surface, the facing surface, and the second inclined surface have a coat having reflection and transmission characteristics. It has two parallel planes that guide the image light by repeating total reflection, and a parallel plane member is joined to at least one of the two planes, and the joint portion of the parallel plane member is joined. The light guide member according to any one of claims 1 to 7, wherein the light guide member has a coating having reflection and transmission characteristics. Image display element and
The light guide member according to any one of claims 1 to 8, wherein the image light emitted from the image display element is guided and emitted.
An optical system that causes the image light emitted from the image display element to enter the light guide member, and an optical system.
Display device.

Images