JP2023003775A - Light guide member and display device - Google Patents

Abstract

To provide a light guide member and a display device that emit image light scatteringly.SOLUTION: A light guide member 300 comprises: a beam emission unit 304 for emitting light-guided image light to the outside; and a first face 305 for reflecting the image light toward the beam emission unit 304, causing it to be emitted from the beam emission unit 304. The plurality of first faces 305 are arranged in a direction in which the image light is guided, and a downstream-side first face 305F among the plurality of first faces 305 that is arranged downstream of the direction in which the image light is guided is inclined, with respect to upstream-side first faces 305B, 305D that are arranged downstream of the direction in which the image light is guided, in a direction in which a distance from the beam emission unit 304 increases on the downstream side of the direction in which the image light is guided.SELECTED DRAWING: Figure 4

Description

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

Japanese Patent Application Laid-Open No. 2002-100003 has a light incident portion for taking in image light, and first and second total reflection surfaces extending in opposition to each other, and the image light taken in from the light incident portion A light guide portion guided by total reflection on a reflective surface, and a light exit portion having an image output portion capable of outputting image light incident through the light guide portion to the outside by bending an optical path, wherein the image output portion comprises: In order to reflect the image light guided by the light guide section, a plurality of second total reflection surfaces extend so as to incline toward the inner side of the light guide section on the back side in the light guide direction of the light guide section with reference to the second total reflection surface. A light guide plate is disclosed in which one element surface and a plurality of second element surfaces extending at an obtuse angle with respect to the first element surface are alternately arranged.

Japanese Patent No. 5703875

An object of the present invention is to provide a light guide member and a display device that diverge and emit incident light.

Claim 1 of the present invention comprises an interface for emitting the guided image light to the outside, and a reflecting surface for reflecting the image light toward the interface and emitting the image light from the interface. A plurality of reflecting surfaces are arranged in the direction in which the image light is guided, and among the plurality of reflecting surfaces, the downstream reflecting surface arranged on the downstream side in the direction in which the image light is guided is the upstream in the direction in which the image light is guided. A light guide member that is inclined in a direction that increases the distance from the interface on the downstream side in the direction in which the image light is guided with respect to the upstream reflection surface arranged on the side.

According to the present invention, it is possible to provide a light guide member and a display device that diverge and emit incident light.

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 apparatus 1000 using the same. It is the figure which showed a mode that the light which propagated the inside of the light guide member 300 which concerns on this embodiment is emitted. It is a figure which shows the light which propagates the inside of the light guide member 300 which concerns on this embodiment. FIG. 3 is an explanatory diagram of an image extraction section 303 in the light guide member 300 according to the embodiment; 3 is a detailed explanatory diagram of an image taking-out portion 303 in the light guide member 300 according to this embodiment; FIG. FIG. 5 is an explanatory diagram of a modified example of the image extraction section 303 in the light guide member 300 according to the present embodiment; FIG. 10 is an explanatory diagram of a second modified example of the image extraction section 303 in the light guide member 300 according to the present embodiment; FIG. 11 is an explanatory diagram of a third modified example of the image extraction section 303 in the light guide member 300 according to the present embodiment; FIG. 11 is an explanatory diagram of a fourth modified example of the image pickup section 303 in the light guide member 300 according to the present embodiment; FIG. 4 is an explanatory diagram of parameters of the light guide member 300 according to the embodiment; FIG. 3 is an explanatory diagram of parameters of an image extraction unit 303 in the light guide member 300 according to the embodiment; 1 is a diagram showing an optical system layout of a virtual image display device 1000 according to this embodiment; FIG. FIG. 4 is an explanatory diagram of a spot diagram in the virtual image display device 1000 according to this embodiment; FIG. 4 is a diagram obtained by simulating a spot diagram at a point A of the virtual image display device 1000 according to the present embodiment; FIG. 4 is a diagram obtained by simulating a spot diagram at point B of the virtual image display device 1000 according to the present embodiment. FIG. 4 is a diagram obtained by simulating a spot diagram at point C of the virtual image display device 1000 according to the present embodiment. FIG. 4 is a diagram obtained by simulating a spot diagram at a point D of the virtual image display device 1000 according to the present embodiment; FIG. 4 is a diagram obtained by simulating a spot diagram at point E of the virtual image display device 1000 according to the present embodiment. 4A and 4B are diagrams showing usage states of various examples of the virtual image display device 1000 according to the present embodiment. FIG.

FIG. 1 is a diagram showing an example of a light guide member 300 and a virtual image display device 1000 using the light guide member 300 according to an embodiment of the present invention. The virtual image display device 1000 is an example of a display device, and includes an image display element 100 for emitting and outputting image light of a display image, an optical system 200 for collimating and emitting image light from the image display element 100, and a guide. An optical member 300 is provided as a virtual image display optical system.

The image display element 100 is a device that outputs image light of a display image that is the basis of a virtual image displayed through the light guide member 300 . An organic LED (OLED: Organic Light Emitting Diode) or a transmissive liquid crystal display element is suitable for the image display element 100, but other various display methods can be applied. For example, a DMD (Digital Micromirror Device) is applicable as the image display element 100 . As the image display element 100, TFT (Thin Film Transistor) or LCOS (Liquid Crystal On Silicon) can be applied. Furthermore, MEMS (Micro Electro Mechanical Systems) can be applied as the image display element 100 . Taking an OLED array as an example of the image display element 100, the size of the image display area (pixel array area) is, for example, 3 mm×4 mm, and the number of pixels is about 10,000.

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 when an LCOS or DMD that requires a light source is used. 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 an example of an incident optical system, and includes a plurality of optical lenses, a diaphragm, and the like.

The light guide member 300 includes a light entrance portion 301 , a light guide portion 302 , an image extraction portion 303 and a light exit portion 304 . The light beam emitting portion 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 the image display element 100 corresponding to horizontal virtual image display. The image light emitted from the center of the image display element 100 converts the positional information of the image display element 100 into angle information by the optical system 200 having the function of a collimating optical system, and enters the light guide member 300 from the light incident portion 301. Incident.

The light that has entered the light guide member 300 becomes a guided light flux, and propagates while repeating total reflection on the parallel facing surfaces of the light guide section 302 .

When light hits the image extraction unit 303, the light is emitted from the light emitting unit 304 and enters the user's eyes. By looking forward through the light beam emitting portion 304 of the light guide member 300, the user can form a "virtual conjugate image" on the retina and visually recognize the virtual image of the image light. That is, the user observes the image display element 10 through the light guide member 300 due to the action of the optical system 200 between the image display element 10 and the light guide member 300 .

FIG. 2 is a diagram showing how the light propagated through the light guide member 300 according to this embodiment is emitted.

As shown in FIG. 2, the image extractor 303 has at least a plurality of first surfaces 305 and a plurality of second surfaces 306, respectively.

The first surface 305 is an example of a first inclined surface that is inclined so that the distance from the light beam exiting portion 304 becomes smaller in the direction in which the image light is guided. It is an example of a reflecting surface that reflects and emits from the light emitting portion 304 . The second surface 306 is an example of a facing surface that is arranged between two adjacent first surfaces 305 , is parallel to the light emitting portion 304 and faces the light emitting portion 304 . A plurality of first surfaces 305 are arranged in the direction in which the image light is guided.

When the light propagated while repeating total reflection in the light guide section 302 hits the first surface 305, it is emitted from the light emitting section 304 and reaches the eye. In addition, by providing the second surface 306, it is possible to advance toward the back of the light guide member 300 until it hits the first surface 305, and the light is guided toward the light beam exit part 304 even at the back of the light guide member 300. be able to. By doing so, it is possible to realize the 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 through the light guide member 300 according to this embodiment.

FIG. 3 shows light 201 that propagates at an angle θ1 with the smallest reflection angle with respect to the light emitting portion 304, among the light that propagates by total reflection on the upper surface 308 and the lower surface 309 of the light guide portion 302 of the light guide member 300. Light 202 propagating at the largest angle θ2 is shown, and light from pixels at both ends of the image display element 100 in the plane of FIG. 3 is shown. That is, the viewing angle can be widened by decreasing θ1 and increasing θ2.

FIG. 4 is an explanatory diagram of the image extraction section 303 in the light guide member 300 according to this embodiment.

When visualizing a virtual image by image light emitted from the light guide member 300 , adjusting the divergence angle of the light flux emitted from the optical system 200 may be considered to adjust the virtual image distance.

However, when a divergent light beam is emitted from the optical system 200, propagation of the divergent light beam within the light guide member 300 may cause a problem such as a pixel shift in which a virtual image is double observed.

On the other hand, when the parallel light flux is emitted from the optical system 200, the parallel light flux is emitted from the light guide member 300, so the virtual image distance is infinite.

Therefore, in this embodiment, the virtual image distance is adjusted by adjusting the divergence angle of the image light emitted from the light guide member 300 with respect to the incident light incident on the light guide member 300 .

As an example, even when the light flux emitted from the optical system 200 is parallel light, the image light emitted from the light guide member 300 is divergent light, thereby making the virtual image distance finite.

In the image extraction unit 303 shown in FIG. 4, a plurality of first surfaces 305A to 305F and a plurality of second surfaces 306A to 306F are arranged in the direction in which the image light is guided. The second surfaces 306B to 306F are arranged between two adjacent first surfaces 305 among the plurality of first surfaces 305A to 305F.

Here, among the plurality of first surfaces 305, the downstream first surface 305F arranged downstream in the direction in which the image light is guided is arranged upstream in the direction in which the image light is guided. With respect to the first surface 305D on the upstream side, it is inclined in the direction in which the distance from the light emitting section 304 is increased on the downstream side in the direction in which the image light is guided.

As a result, the exit light (dotted line) reflected by the upstream first surface 305D and emitted from the light beam exit portion 304 and the exit light (solid line) reflected by the downstream first surface 305F and exited from the beam exit portion 304 The angle formed can be made larger than the angle formed by the incident light incident on the upstream side first surface 305D and the incident light incident on the downstream side first surface 305F.

Similarly, the first surface 305D is located on the downstream side in the direction in which the image light is guided with respect to the upstream side first surface 305B arranged on the upstream side in the direction in which the image light is guided. It is tilted in the direction that the distance from

That is, each of the downstream side first surfaces 305B to 305E is positioned further downstream in the direction in which the image light is guided with respect to the upstream side first surface 305A. It is formed so that the inclination angle becomes larger in the direction where the distance from the light emitting portion 304 becomes larger on the downstream side.

The inclination angles of the first surfaces 305A to 305E may not all be different. For example, the first surface 305C arranged between the first surfaces 305B and 305D may You may form so that it may become parallel to one side.

In addition, in the image extraction unit 303 shown in FIG. 4, the incident light incident on the upstream first surfaces 305B and 305D and the incident light incident on the downstream first surface 305F are parallel. As a result, the light guide member 300 causes the light to be reflected by the upstream first surfaces 305B and 305D and emitted from the light emitting portion 304 without causing problems such as color shift caused by guiding non-parallel incident light. The emitted light and the emitted light reflected by the downstream side first surface 305F and emitted from the light emitting portion 304 can be divergent light.

Further, the downstream side first surface 305F is located downstream in the direction in which the image light is guided with respect to the upstream side first surface 305E arranged adjacent to the upstream side in the direction in which the image light is guided. It inclines in the direction in which the distance from the light emitting portion 304 increases.

As a result, the angle formed by the light reflected by the upstream first surface 305E and the downstream first surface 305F, which are arranged adjacent to each other, and emitted from the light emitting portion 304 is , the angle can be made larger than the angle formed by each incident light incident on the downstream side first surface 305F.

Here, the angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E is larger than 0.002 degrees and smaller than 0.210 degrees.

As a result, the two light beams reflected by the upstream first surface 305E and the downstream first surface 305F, which are arranged adjacent to each other, are emitted from the light beam emitting unit 304, thereby reducing the virtual image distance to about 0.3 to 2 m. can be done.

When the angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E exceeds the upper limit value of 0.210 degrees, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. . On the other hand, if the angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E is less than the lower limit of 0.002 degrees, the virtual image distance becomes almost infinite. On the other hand, in this embodiment, the user can easily focus on the virtual image while making the virtual image distance finite.

Between two adjacent first surfaces 305E and 305F, there is a second surface 306F facing parallel to the light emitting portion 304. As shown in FIG.

As a result, the two diverging lights reflected by the two first surfaces 305E and 305F and emitted from the light emitting section 304 can enlarge the pupil and secure an eyebox while maintaining a wide angle of view. Further, more light can reach the first surface 305 on the far side of the light guide member 300 .

FIG. 5 is a detailed explanatory diagram of the image extraction section 303 in the light guide member 300 according to this embodiment.

FIG. 5(a) is a diagram showing the image extraction unit 303 on the YZ plane, and is the same as FIG. FIG. 5B is a diagram showing the image extractor 303 on the XZ plane.

In FIG. 5, the XZ plane is a plane parallel to the light emitting portion 304, the Z direction is the direction in which image light is guided and the direction in which the plurality of first surfaces 305A to 305E are arranged, and the Y direction is the direction perpendicular to the XZ plane and the ray exit portion 304 . As shown in FIG. 5B, the shape of each of the plurality of first surfaces 305A to 305E in the cross section parallel to the XZ plane is the upstream side (−Z side) in the Z direction in which the image light is guided. is formed into a convex shape.

As a result, the incident light incident on each of the plurality of first surfaces 305A to 305E can be diverged in the X direction, reflected, and emitted from the light emitting section 304. Even if the incident light is a parallel light beam, the light reflected by each of the plurality of first surfaces 305A to 305E and emitted from the light emitting portion 304 can make the virtual image distance finite.

In this embodiment, each of the plurality of first surfaces 305A to 305E is formed in a curved surface shape so that a cross section parallel to the XZ plane has a curved shape. Each of the first surfaces 305A to 305E may be formed in a polyhedral shape such that a cross section parallel to the XZ plane is formed by a plurality of straight lines.

The radius of curvature of each of the plurality of first surfaces 305A-305E is larger than 800 mm and smaller than 10000 mm. As a result, the virtual image distance can be made about 0.3 to 2 m by divergent light reflected by each of the plurality of first surfaces 305A to 305E and emitted from the light emitting portion 304. FIG.

When the radius of curvature of each of the plurality of first surfaces 305A to 305E exceeds the upper limit of 10000 mm, the virtual image distance becomes almost infinite. On the other hand, if the radius of curvature of each of the plurality of first surfaces 305A to 305E is less than the lower limit of 800 mm, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. On the other hand, in this embodiment, the user can easily focus on the virtual image while making the virtual image distance finite.

FIG. 6 is an explanatory diagram of a modified example of the image extraction section 303 in the light guide member 300 according to this embodiment.

FIG. 6(a) is an enlarged view of the image retrieving unit 303 shown in FIGS. 4 and 5, and FIG. 6(b) is an enlarged view of the image retrieving unit 303 according to a modification.

In FIG. 6(b), a third surface 307 inclined in a direction different from that of the first surface 305 is newly provided with respect to FIG. 6(a). The third surface 307 is provided between the first surface 305 and the second surface 306, and is a second inclined surface that is inclined so as to increase the distance from the light emitting portion 304 in the direction in which the image light is guided. is an example.

The light shown by solid lines and dotted lines in FIGS. 6A and 6B is light emitted from the same pixel of the image display element 100, and is emitted from the light guide member at the same angle by the optical system 200 having the function of a collimating optical system. Propagate within 300 .

At this time, the light indicated by the dotted line in FIG. 6(a) directly hits the first surface 305 after being reflected by the second surface 306 and travels in the direction of the light emitting portion 304, whereas in FIG. By providing the three surfaces 307 , it is possible to prevent light from directly hitting the first surface 305 after being reflected by the second surface 306 .

As a result, of the light propagating in the light guide member 300 by total 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 the modified example shown in FIG. 6(b), the degree of difficulty in molding is increased in order to form the third surface 307. However, as shown in FIG. In FIG. 6A, it is possible to prevent 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 .

FIG. 7 is an explanatory diagram of a second modified example of the image extraction section 303 in the light guide member 300 according to this embodiment.

FIG. 7(a) is a detailed explanatory diagram of the image extraction unit 303 according to the modification shown in FIG. 6(b), and FIG. 7(b) is a detailed illustration of the image extraction unit 303 according to the second modification. It is an explanatory diagram.

The image extraction unit 303 according to the modified example shown in FIG. A third surface 307B, a first surface 305B and a second surface 306C are arranged in order.

On the other hand, the image extraction unit 303 according to the second modification shown in FIG. The second surface 306B, the first surface 305B, the third surface 307B and the second surface 306C are arranged in order.

In the image extraction unit 303 according to the modification shown in FIG. 7A, the second surface 306B, the third surface 307B, and the first surface 305B, which are arranged downstream in the direction in which the image light is guided, The second surface 306A, the third surface 307A, and the first surface 305A, which are arranged upstream in the direction in which the light is guided, are arranged closer to the light beam exit part 304. As shown in FIG.

On the other hand, in the image extraction unit 303 according to the second modification shown in FIG. 7B, the second surface 306B, the first surface 305B, the third The surface 307B and the second surface 306A, the first surface 305A, and the third surface 307A arranged on the upstream side in the direction in which the image light is guided are the same distance from the light beam emitting portion 304 .

The light guide member 300 according to the second modification shown in FIG. 7B is heavier than the light guide member 300 according to the modification shown in FIG. 7A, but is easier to mold. .

FIG. 8 is an explanatory diagram of a third modified example of the image extraction section 303 in the light guide member 300 according to this embodiment.

In the image extraction unit 303 according to the third modification shown in FIG. 8, in the same manner as the image extraction unit 303 according to the modification shown in FIG. 306A, first surface 305A, third surface 307A, second surface 306B, first surface 305B, third surface 307B, and second surface 306C are arranged in order.

In the image extraction unit 303 according to the modification shown in FIG. 7A, the second surface 306B, the third surface 307B, and the first surface 305B, which are arranged downstream in the direction in which the image light is guided, The second surface 306A, the third surface 307A, and the first surface 305A, which are arranged upstream in the direction in which the light is guided, are arranged closer to the light beam exit part 304. As shown in FIG.

On the other hand, in the image extraction unit 303 according to the third modification shown in FIG. , the second surface 306A, the third surface 307A, and the first surface 305A, which are arranged on the upstream side in the direction in which the image light is guided, have the same distance from the light beam exit portion 304. As shown in FIG.

The light guide member 300 according to the third modification shown in FIG. 8 is also lighter than the light guide member 300 according to the modification shown in FIG. 7A, but is easier to mold.

FIG. 9 is an explanatory diagram of a fourth modified example of the image extraction section 303 in the light guide member 300 according to this embodiment.

The second surface 306 is not arranged in the image extraction unit 303 according to the fourth modification shown in FIG. The third surface 307B, the first surface 305B, the third surface 307C and the first surface 305C are arranged in order.

In the light guide member 300 according to the fourth modified example shown in FIG. 9, the eyebox and the angle of view are small, but the unevenness of the intensity of the light rays entering the eye at each angle of view is small.

FIG. 10 is an explanatory diagram of parameters of the light guide member 300 according to this embodiment. FIG. 11 is an explanatory diagram of the parameters of the image extraction section 303 in the light guide member 300 according to this embodiment.

■ Performance ・Eye box: 2.5mm or more ・Eye relief: 15mm
・Diagonal angle of view: 40 degrees ・Virtual image distance: 300 mm

A parallel plane member 310 is joined to the light guide member 300, and the interface between the light guide member 300 and the member 310 is a half mirror.
■ Member 310
・Thickness hd: 0.6mm
■ Light guide member 300
・ Thickness wd: 2.5 mm at the thickest part
・Light guide member width ww: 50mm
・Width l of first surface 305: 0.2 mm
・Number of first surfaces 305 num: 24
・Width w of second surface 306: 0.6 mm
・Refractive index: 1.493612 (PMMA)
・ Reflective surface curvature radius R: 800 mm
・The angles of the 24 first surfaces 305 with respect to the second surface 306 were set as shown in Table 1.

The number num of the plurality of first surfaces 305 is within the range of 10-25. If the number exceeds the upper limit of 25, the first surface 305 becomes an obstacle when looking outside through the light guide member 300 . If the lower limit of 10 is not reached, the eyebox in the horizontal direction will become narrower, and the viewing angle will also become narrower. In this embodiment, it is possible to easily see the outside through the light guide member 300, and the eyebox in the horizontal direction is widened, and the viewing angle is also widened.

A distance W connecting both ends of the opposing surfaces in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and smaller than 3 mm. As a result, it is possible to secure an eyebox while maintaining a wide angle of view.

Assuming that the size of the eye is 3 mm, if the upper limit of 3 mm is exceeded, light with an angle of view that does not reach the eye is generated. It becomes difficult to enlarge the eye box while maintaining the angle of view. In the present embodiment, it is possible to increase the eyebox while ensuring a sufficient amount of light and a wide angle of view.

A distance l connecting both ends of the first surface 305B in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and smaller than 1 mm.

If the upper limit of 1 mm is exceeded, the first surface 305 becomes an obstacle when looking outside through the light guide member 300 . If the lower limit of 0.1 mm is not reached, the resolution will be low due to the diffraction limit. In this embodiment, it is possible to improve the resolution while making it easier to see the outside through the light guide member 300 .

FIG. 12 is a diagram showing the optical system layout of the virtual image display device 1000 according to this embodiment.
The optical system 200 in FIG. 12 forms an intermediate image of the light emitted from the image display element 100 once, generates substantially collimated light, and causes the light to enter the light guide member 300 . By once forming an intermediate image in this way, the heavy image display element 100 can be arranged at the rear. Therefore, when the virtual image display device 1000 is a spectacles type, the front weight can be reduced, and the spectacles type virtual image is comfortable to wear. A display device can be realized.

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

FIG. 13 is an explanatory diagram of a spot diagram in the virtual image display device 1000 according to this embodiment.

As shown in FIG. 13, the positions for which the spot diagram was calculated are point A (0, 0), point B (2.3, 0), point C (-2.3, 0), point D (0, 1 .5), the point E(0,-1.5).

14 to 18 are diagrams obtained by simulating spot diagrams at points A to E of the virtual image display device 1000 according to this embodiment.

FIG. 19 is a diagram showing usage states of various examples of the virtual image display device 1000 according to the present embodiment.
FIGS. 19A, 19B, and 19C illustrate a case where the light guide member 300 is applied to a glasses-type virtual image display device, ie, an HMD.

The example shown in FIG. 19A is a case where one light guide member 300 is applied to a binocular HMD. A mirror 350 that guides light into the light guide member 300 is arranged on the right side of the virtual image observer, ie, the user. The light guide member 300 is fixed to a frame portion 500 that serves as a temple that is worn over the user's ear. Although the frame portion is simplified in FIG. 26, the frame portion 500 can have a shape that covers not only both end sides of the light guide member 300 but also the upper edge and the lower edge.

On the other hand, the examples shown in FIGS. 19B and 19C are cases in which one light guide member 300 is miniaturized and applied to an HMD. The example shown in FIG. 19(b) is a case where two light guide members 300 are arranged corresponding to the positions of the user's left and right eyes as a binocular HMD. 8 are arranged on the left and right outer sides. FIG. 19(c) shows a monocular HMD in which one light guide member 300 is arranged so as to correspond to the position of either the left or right eye of the user.

Although illustration of the virtual image optical system and the light source is omitted in FIG. 19, these can be attached to the frame section 500. 19A and 19C, the light source 52, the image display device 100, and the optical system 200 are placed in the right-eye frame portion, and in the example shown in FIG. should be attached to

In the example shown in FIG. 19, the case where the light guide member 300 is applied to an eyeglass-type HMD has been described. Moreover, the light guide member 300 of each of the embodiments described above can be applied to other types of HMDs, and can also be applied to head-up displays (HUDs). The light guide member of each embodiment is particularly suitable for virtual image display of an original image formed by light beams optically modulated by microdevices.

As described above, the light guide member 300 can be worn on a person's face like eyeglasses. Then, when the image light of the image display device or the like is collimated and entered from the light incident portion 301, as already described, the image of the image display device or the like can be observed as a virtual image. Since the light guide member 300 is a transparent body, the surrounding scene can be observed together with the image.

The thickness of the light guide member 300 is about 1 mm to 4 mm, and the material is preferably resin. Such a configuration makes the light guide member 300 sufficiently light, reduces the burden on the user's nose, and is easy to use.

●Summary●
As described above, the light guide member 300 according to one embodiment of the present invention includes the light beam emitting portion 304, which is an example of an interface (boundary surface) for emitting the guided image light to the outside, and the light beam emitting portion 304 that emits the image light. and a first surface 305, which is an example of a reflecting surface that reflects toward the light emitting unit 304 and emits the light from the light emitting unit 304. A plurality of the first surfaces 305 are arranged in the direction in which the image light is guided. Among the plurality of first surfaces 305, the downstream first surface 305F arranged on the downstream side in the direction in which the image light is guided is the upstream side arranged on the upstream side in the direction in which the image light is guided. With respect to the side first surfaces 305B and 305D, the side first surfaces 305B and 305D are inclined in a direction in which the distance from the light beam exiting portion 304 is increased on the downstream side in the direction in which the image light is guided.

As a result, the angle formed by the light reflected by the first upstream surfaces 305B and 305D and emitted from the light emitting portion 304 and the light emitted from the light emitting portion 304 after being reflected by the first downstream surface 305F is The angle formed by the incident light incident on the upstream first surfaces 305B and 305D and the incident light incident on the downstream first surface 305F can be made larger.

Each of the downstream side first surfaces 305B to 305E is positioned further downstream in the direction in which the image light is guided with respect to the upstream side first surface 305A, the further downstream in the direction in which the image light is guided. , the angle of inclination is increased in the direction in which the distance from the light emitting portion 304 is increased.

Alternatively, the angles of inclination of the first surfaces 305A-305E may not all be different, for example, the first surface 305C located between the first surfaces 305B and 305D may may be formed so as to be parallel to either one of

In addition, when the incident light incident on the upstream side first surfaces 305B and 305D and the incident light incident on the downstream side first surface 305F are parallel, color misregistration and the like caused by guiding non-parallel incident light may occur. Without causing any problem, the light guide member 300 allows the emitted light reflected by the upstream side first surfaces 305B and 305D to be emitted from the light emitting section 304, and the light reflected by the downstream side first surface 305F to be emitted from the light emitting section 304. Emitted light can be divergent light.

The downstream side first surface 305F emits light rays downstream in the direction in which the image light is guided with respect to the upstream side first surface 305E, which is arranged adjacent to the upstream side in the direction in which the image light is guided. It inclines in the direction in which the distance from the portion 304 increases.

As a result, the angle formed by the light reflected by the upstream first surface 305E and the downstream first surface 305F, which are arranged adjacent to each other, and emitted from the light emitting portion 304 is , the angle can be made larger than the angle formed by each incident light incident on the downstream side first surface 305F.

The angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E is greater than 0.002 degrees and less than 0.210 degrees.

As a result, when a virtual image is formed by two light beams reflected by the adjacent upstream first surface 305E and downstream first surface 305F and emitted from the light beam emitting portion 304, the virtual image distance can be set to about 0.3 to 2 m.

When the angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E exceeds the upper limit value of 0.210 degrees, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. . On the other hand, if the angle at which the downstream first surface 305F is inclined with respect to the upstream first surface 305E is less than the lower limit of 0.002 degrees, the virtual image distance becomes almost infinite. On the other hand, in this embodiment, the user can easily focus on the virtual image while making the virtual image distance finite.

Each of the plurality of first surfaces 305A-305E is formed in a convex shape. As an example, the shape of each of the plurality of first surfaces 305A to 305E in the cross section parallel to the light beam exiting portion 304 (XZ plane) is the same as the image light guiding direction in the Z direction, which is the image light guiding direction. is formed in a convex shape on the upstream side of the .

As a result, incident light incident on each of the plurality of first surfaces 305A to 305E can be diverged in the X direction, for example, and emitted from the light emitting section 304. FIG. When a virtual image is formed for each of the plurality of first surfaces 305A to 305E by the emitted light reflected by each of the plurality of first surfaces 305A to 305E and emitted from the light emitting portion 304, the virtual image distance is finite. can do.

Each of the plurality of first surfaces 305A-305E is formed in a curved shape. As an example, each of the plurality of first surfaces 305A to 305E is formed in a curved shape such that a section parallel to the XZ plane has a curved shape. As another form, each of the plurality of first surfaces 305A to 305E may be formed in a polyhedral shape such that a cross section parallel to the XZ plane is formed by a plurality of straight lines.

The radius of curvature of each of the plurality of first surfaces 305A-305E is larger than 800 mm and smaller than 10000 mm.

As a result, when a virtual image is formed for each of the plurality of first surfaces 305A to 305E by the divergent light reflected by each of the plurality of first surfaces 305A to 305E and emitted from the light beam emitting portion 304, the virtual image distance can be set to about 0.3 to 2 m.

When the radius of curvature of each of the plurality of first surfaces 305A to 305E exceeds the upper limit of 10000 mm, the virtual image distance becomes almost infinite. On the other hand, if the radius of curvature of each of the plurality of first surfaces 305A to 305E is less than the lower limit of 800 mm, the virtual image distance becomes too close, making it difficult for the user to focus on the virtual image. On the other hand, in this embodiment, the user can easily focus on the virtual image while making the virtual image distance finite.

Between two adjacent first surfaces 305E and 305F, there is a second surface 306F facing parallel to the light emitting portion 304. As shown in FIG.

Accordingly, when a virtual image is formed by two diverging lights reflected by the two first surfaces 305E and 305F and emitted from the light emitting section 304, the pupil can be enlarged and the eye can be enlarged while the angle of view is wide. You can secure the box. Further, more light can reach the first surface 305 on the far side of the light guide member 300 .

A distance W connecting both ends of the opposing surfaces in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and smaller than 3 mm. As a result, it is possible to secure an eyebox while maintaining a wide angle of view.

Assuming that the size of the eye is 3 mm, if the upper limit of 3 mm is exceeded, light with an angle of view that does not reach the eye is generated. It becomes difficult to enlarge the eye box while maintaining the angle of view. On the other hand, in the present embodiment, it is possible to increase the eyebox while ensuring the light amount and the wide angle of view.

A distance l connecting both ends of the first surface 305B in the direction in which the plurality of first surfaces 305A to 305D are arranged is longer than 0.1 mm and smaller than 1 mm.

If the upper limit of 1 mm is exceeded, the first surface 305 becomes an obstacle when looking outside through the light guide member 300 . If the lower limit of 0.1 mm is not reached, the resolution will be low due to the diffraction limit. On the other hand, in this embodiment, it is possible to improve the resolution while making it easier to see the outside through the light guide member 300 .

The number num of the plurality of first surfaces 305 is within the range of 10-25. If the number exceeds the upper limit of 25, the first surface 305 becomes an obstacle when looking outside through the light guide member 300 . If the lower limit of 10 is not reached, the eyebox in the horizontal direction will become narrower, and the viewing angle will also become narrower. On the other hand, in the present embodiment, it is easy to see outside through the light guide member 300, and the eyebox in the horizontal direction is widened, and the viewing angle is widened.

The incident light incident on the downstream side first surface 305 and the incident light incident on the upstream side first surface 305 are substantially parallel. As a result, parallel light incident on the upstream first surface 305 and the downstream first surface 305 can be emitted as divergent light.

A virtual image display device 1000, which is an example of a display device according to an embodiment of the present invention, includes a light guide member 300, an image display element 100 that emits image light, and an incident optical system that causes the image light to enter the light guide member. The light guide member 300 includes an optical system 200 that is an example, and the light guide member 300 includes a light beam emitting portion 304 that emits the guided image light to the outside, and a light beam emitting portion 304 that reflects the image light toward the light beam emitting portion 304. a plurality of first surfaces 305 are arranged in the direction in which the image light is guided, and among the plurality of first surfaces 305, the image light is guided; The downstream first surface 305F arranged on the downstream side in the direction in which the image light is guided to the upstream first surfaces 305B and 305D arranged on the upstream side in the direction in which the image light is guided. It is tilted in a direction in which the distance from the light beam emitting portion 304 is increased on the downstream side in the direction in which the beam is projected.

As a result, the light guide member 300 has an output light reflected by the first surfaces 305B and 305D on the upstream side and emitted from the light emitting portion 304, and an output light reflected by the first surface 305F on the downstream side and emitted from the light emitting portion 304. The virtual image distance can be shortened by making the angle formed by the light larger than the angle formed by the incident light incident on the upstream side first surfaces 305B and 305D and the incident light incident on the downstream side first surface 305F. .

In addition, when the incident light incident on the light guide member 300 from the optical system 200 is parallel, a problem such as a pixel shift in which a virtual image is double observed occurs due to the non-parallel incident light being guided. The light guide member 300 reflects the light from the first surfaces 305B and 305D on the upstream side and exits from the light emitting portion 304, and the first surface 305F on the downstream side reflects the light from the light emitting portion 304. The virtual image distance can be made finite by making the emitted light divergent light.

100 image display element 200 incident optical system (optical system)
201 Light 202 that propagates at the minimum value θ1 of the reflection angle θ with respect to the light emitting portion 304 Light 300 that propagates at the maximum value θ2 of the reflection angle θ with respect to the light emitting portion 304 Light guide member 301 Light incident portion 302 Light guide portion 303 Image extraction portion 304 ray exit part (interface, boundary surface)
305 first surface (reflective surface, first inclined surface)
306 second surface (opposing surface)
307 Third surface (second inclined surface)
310 parallel plane member 1000 virtual image display device (display device)

Claims (12)

an interface for emitting the guided image light to the outside;
a reflecting surface that reflects the image light toward the interface and emits the image light from the interface;
with
A plurality of the reflective surfaces are arranged in a direction in which the image light is guided,
Among the plurality of reflecting surfaces, the downstream reflecting surface arranged downstream in the direction in which the image light is guided is the upstream reflecting surface arranged in the upstream in the direction in which the image light is guided. , the light guide member is inclined in a direction in which the distance from the interface increases on the downstream side in the direction in which the image light is guided. The downstream-side reflecting surface is located downstream in the direction in which the image light is guided with respect to the upstream-side reflecting surface arranged adjacent to the upstream side in the direction in which the image light is guided. 2. The light guide member according to claim 1, which is inclined in a direction in which the distance from the . 3. The light guide member according to claim 2, wherein an angle at which the downstream reflecting surface is inclined with respect to the upstream reflecting surface is larger than 0.002 degrees and smaller than 0.210 degrees. 4. The light guide member according to any one of claims 1 to 3, wherein each of said plurality of reflecting surfaces is formed in a convex shape. 5. The light guide member according to claim 4, wherein each of the plurality of reflective surfaces is curved. 6. The light guide member according to claim 5, wherein the radius of curvature of each of the plurality of reflecting surfaces is larger than 800 mm and smaller than 10000 mm. 7. The light guide member according to any one of claims 1 to 6, further comprising a facing surface facing parallel to said interface between said two adjacent reflecting surfaces. 8. The light guide member according to claim 7, wherein a distance connecting both ends of said facing surface in a direction in which said plurality of reflecting surfaces are arranged is longer than 0.1 mm and smaller than 3 mm. 9. The light guide member according to any one of claims 1 to 8, wherein a distance connecting both ends of said reflecting surfaces in a direction in which said plurality of reflecting surfaces are arranged is longer than 0.1 mm and smaller than 1 mm. The light guide member according to any one of claims 1 to 9, wherein the number of said plurality of reflective surfaces is within a range of 10 to 25. The light guide member according to any one of claims 1 to 10, wherein the incident light incident on the downstream reflecting surface and the incident light incident on the upstream reflecting surface are substantially parallel.
a light guide member according to any one of claims 1 to 10;
an image display element that emits the image light;
and an incident optical system that causes the image light to enter the light guide member.

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