CN217902097U

CN217902097U - Waveguide device and display system

Info

Publication number: CN217902097U
Application number: CN202222391531.0U
Authority: CN
Inventors: 魏一振; 张卓鹏
Original assignee: Hangzhou Guangli Technology Co ltd
Current assignee: Hangzhou Guangli Technology Co ltd
Priority date: 2022-09-05
Filing date: 2022-09-05
Publication date: 2022-11-25
Anticipated expiration: 2032-09-05

Abstract

The utility model discloses a waveguide device and display system belongs to optics technical field. A waveguide device and display system includes a waveguide substrate and a holographic optical element; the waveguide substrate is provided with a first surface and a second surface which are arranged in parallel relatively, and a third surface and a fourth surface which are arranged between the ends of the first surface and the second surface; the third surface and the fourth surface are both obliquely arranged; the third surface is used for reflecting the incident light into the waveguide substrate; the fourth surface is used for reflecting the light totally reflected out of the waveguide substrate to the holographic optical element; the first surface and the second surface are used for totally reflecting light rays onto the fourth surface; the holographic optical element is attached to the surface, close to the fourth surface, of the second surface and used for diffracting the light reflected to the holographic optical element to enter human eyes; the effects of being lighter, thinner and more convenient to carry can be realized, the light loss can be reduced, and the imaging effect of the image is improved.

Description

Waveguide device and display system

Technical Field

The utility model relates to the field of optical technology, more specifically say, relate to a waveguide device and display system.

Background

Augmented Reality (AR) technology is a technology for fusing virtual information with a real world, and when an Augmented Reality device is used, it is ensured that both the virtual information and the real external world can be observed.

The optical waveguide is a device which can bind the signal light in the optical waveguide and transmit the signal light towards a specific direction, and the light is transmitted in the optical waveguide by total reflection, so that the loss is low; meanwhile, the optical waveguide has good light transmission and is light and thin, so that the optical waveguide is suitable for near-eye display, and the optical expansion amount can be increased by adopting a pupil expanding technology. The optical waveguide directionally transmits the signal light projected by the projection light machine to human eyes, so that the human eyes can see the image to be displayed, and because the optical waveguide has good light transmission, the human eyes can clearly see the real environment behind the optical waveguide, so that the human eyes finally see the fusion of the image to be displayed and the real environment.

The optical waveguide can be classified into a geometric optical waveguide, a diffractive optical waveguide and the like according to different implementation principles, for example, as shown in fig. 4, the optical path schematic diagram of a geometric optical waveguide scheme in the prior art is shown, and an incident light ray enters the substrate 21, meets the law of total reflection, is totally reflected in the substrate 21 and propagates forwards, is reflected to the second reflection surface 23 embedded in the prism 24 through the first reflection surface 22, and is then reflected to human eyes through the second reflection surface 23.

The above scheme has the following technical defects: the arrangement of the prism 24 and the second reflecting surface 23 greatly increases the thickness of the whole waveguide device, which can lead to weight increase, limited visual field and great discount in the aspects of carrying and aesthetic feeling when being applied to AR glasses, thereby reducing the satisfaction degree of users; part of the light reflected to the second reflecting surface 23 is reflected to human eyes through the reflecting surface 23, and a small part of the light is transmitted out of the prism 24 to be refracted, so that the light is lost to a certain degree in the process, and the final imaging effect is influenced.

SUMMERY OF THE UTILITY MODEL

1. Technical problem to be solved

To the problem that exists among the prior art, the utility model aims to provide a waveguide device and display system, it can realize frivolous, portable's effect more, can reduce the light loss simultaneously, improves the formation of image effect of image.

2. Technical scheme

In order to solve the problem, the utility model adopts the following technical proposal.

A waveguide device includes a waveguide substrate and a holographic optical element;

the waveguide substrate is provided with a first surface, a second surface, a third surface and a fourth surface, wherein the first surface and the second surface are arranged in parallel relatively, and the third surface and the fourth surface are arranged between the ends of the first surface and the second surface;

the third surface and the fourth surface are obliquely arranged;

the third surface is used for reflecting the incident light to the waveguide substrate;

the fourth surface is used for reflecting the light totally reflected out of the waveguide substrate to the holographic optical element;

the first surface and the second surface are used for totally reflecting light rays onto the fourth surface;

the holographic optical element is attached to the surface, close to the fourth surface, of the second surface and used for diffracting the light reflected to the holographic optical element to enter human eyes.

Further, the third surface and the fourth surface are arranged in parallel.

Further, the holographic optical element is a reflective HOE grating or a transmissive HOE grating.

Further, the light incident on the third surface is parallel light.

Furthermore, the reflection times of the light incident on the third surface are consistent with the reflection times of the light reflected from the fourth surface after being totally reflected by the first surface and the second surface.

Further, still include the compensation prism, the compensation prism laminating sets up the surface of keeping away from one side of second surface at the fourth surface, and has air gap between compensation prism and the fourth surface.

Further, the refractive index of the compensation prism is equal to that of the waveguide substrate.

A display system comprises a waveguide device, a projection light machine and a lens, wherein light rays emitted by the projection light machine are changed into parallel light through the lens and are incident on a third surface.

3. Advantageous effects

Compared with the prior art, the utility model has the advantages of: through the arrangement of the holographic optical element, a mode of coupling out a plurality of reflecting surfaces in the prior art is replaced, the integral thickness of the waveguide device can be greatly reduced, the carrying is convenient, meanwhile, the light loss can be reduced, and the imaging effect of an image is improved; and the holographic optical element can be directly attached to the waveguide substrate for use, and the manufacture is simple.

Drawings

Fig. 1 is a schematic view of an optical path according to the present invention;

fig. 2 is another schematic diagram of the optical path of the present invention;

fig. 3 is a schematic diagram of the theoretical principle of the light b of the present invention;

fig. 4 is a schematic structural diagram of the prior art.

The reference numbers in the figures illustrate:

11 a projection light machine;

12 lenses;

131 a first surface, 132 a second surface, 133 a third surface, 134 a fourth surface;

14 a holographic optical element;

15 compensating prism.

Detailed Description

Example (b):

referring to fig. 1-3, a waveguide device includes a waveguide substrate and a holographic optical element 14; the waveguide substrate has first and

second surfaces

131 and 132 disposed in parallel with each other and third and

fourth surfaces

133 and 134 disposed between ends of the first and

second surfaces

131 and 132.

The third surface 133 and the fourth surface 134 are both obliquely arranged; the third surface 133 and the fourth surface 134 are disposed in parallel with respect to each other.

The light incident to the third surface 133 is parallel light; the third surface 133 is used to reflect the incident light into the waveguide substrate, i.e. the light is reflected by the third surface 133 to enter the waveguide substrate and propagates forward according to the law of total reflection.

The fourth surface 134 is used to reflect light totally reflected off the waveguide substrate to the holographic optical element 14.

The number of reflections of the light incident on the third surface 133 is consistent with the number of reflections of the light reflected from the fourth surface 134 after being totally reflected by the first surface 131 and the second surface 132.

The first surface 131 and the second surface 132 serve to totally reflect the light reflected by the third surface 133 onto the fourth surface 134.

Holographic optical element 14 is attached to second surface 132 on a side thereof adjacent to fourth surface 134 for diffracting light reflected thereon into the human eye, and the particular holographic optical element 14 is attached to the underside of second surface 132, i.e., the side of second surface 132 facing away from first surface 131.

As shown in fig. 3, when the light ray b is incident on the third surface 133, two reflections are generated on the third surface 133, and assuming that an incident angle of the incident light ray b on the third surface 133 is β, and an included angle between the third surface 133 and the first surface 131 is α, it is estimated from a geometric relationship that an incident angle of the light ray b on the fourth surface 134 after first reflection reaches the holographic optical element 14 is β + α, and β + α does not satisfy the bragg condition 2dsin θ = n λ (n is a positive integer), that is, β + α is not within the selective diffraction angle range of the holographic optical element 14, so that the light ray is not diffracted after being reflected on the holographic optical element 14 by the fourth surface 134, and the reflected light ray is reflected back to the holographic optical element 14 after being reflected on the fourth surface 134, and β - α satisfies the bragg condition 2dsin = θ n λ (n is a positive integer), that is β - α satisfies the selective diffraction angle range of the holographic optical element 14, and the light ray enters the holographic optical element 14.

In the above process, the number of times of reflection of the light b incident on the third surface 133 is equal to the number of times of reflection of the light b incident on the fourth surface 134, so that symmetry between the incident light and the emergent light is ensured, symmetry between the emergent light and the incident light is ensured when the light is coupled out, and thus the problem of ghost images in the projected image is avoided.

The holographic optical element 14 is a reflective HOE grating or a transmissive HOE grating.

In some embodiments, the holographic optical element 14 is a reflective HOE grating, as shown in fig. 1, and light that is last reflected to the holographic optical element 14 via the fourth surface 134 is diffracted upward into the human eye.

In other embodiments, the holographic optical element 14 is a transmissive HOE grating, as shown in fig. 2, and light that is last reflected by the fourth surface 134 to the holographic optical element 14 is diffracted downward into the human eye.

The diffraction efficiency of the reflective HOE grating shown in fig. 1 is greater than that of the transmissive HOE shown in fig. 2.

In some preferred embodiments, the waveguide device further includes a compensation prism 15, the compensation prism 15 is attached to a surface of the fourth surface 134 on a side away from the second surface 132, the compensation prism 15 is used for enabling the external light transmitted through the holographic optical element 14 and the waveguide substrate to enter human eyes without distortion, and an air gap is formed between the compensation prism 15 and the fourth surface 134, so that the light totally reflected to the fourth surface 134 through the second surface 132 can be totally reflected to the holographic optical element 14, and the light loss when the light passes through the fourth surface 134 is reduced.

The refractive index of the compensating prism 15 is equal to the refractive index of the waveguide substrate, so that when the holographic optical element 14 is a reflective HOE grating, the light diffracted out by the holographic optical element 14 passes through the fourth surface 134 to be refracted, and the light refracted into the human eye after entering the compensating prism 15 is refracted again and remains parallel to the light diffracted out by the holographic optical element 14.

A display system comprises a waveguide device, a projection light machine 11 and a lens 12, wherein the projection light machine 11 emits light to a waveguide substrate at an angle within a preset angle range, and the light emitted by the projection light machine 11 is changed into parallel light through the lens 12 and is incident on a third surface 133.

Claims

1. A waveguide device, characterized by: comprising a waveguide substrate and a holographic optical element (14);

the waveguide substrate has a first surface (131) and a second surface (132) arranged in parallel and a third surface (133) and a fourth surface (134) arranged between ends of the first surface (131) and the second surface (132);

the third surface (133) and the fourth surface (134) are both obliquely arranged;

said third surface (133) for reflecting incident light rays into the waveguide substrate;

the fourth surface (134) is used for reflecting the light totally reflected out of the waveguide substrate to the holographic optical element (14);

the first surface (131) and the second surface (132) are used for totally reflecting the light reflected by the third surface (133) onto the fourth surface (134);

the holographic optical element (14) is attached to the second surface (132) near the fourth surface (134) and is used for diffracting the light reflected to the holographic optical element into human eyes.

2. A waveguide device according to claim 1, wherein: the third surface (133) and the fourth surface (134) are arranged in parallel relative to each other.

3. A waveguide device according to claim 1, wherein: the holographic optical element (14) is a reflective HOE grating or a transmissive HOE grating.

4. A waveguide device according to claim 1, wherein: the light incident on the third surface (133) is parallel light.

5. A waveguide device according to claim 1, wherein: the number of reflections on the third surface (133) of the light incident on the third surface (133) is consistent with the number of reflections off the fourth surface (134) of the light after the light is totally reflected by the first surface (131) and the second surface (132).

6. A waveguide device according to claim 1, wherein: the novel optical fiber connector further comprises a compensating prism (15), wherein the compensating prism (15) is attached to the surface of the fourth surface (134) on the side far away from the second surface (132), and an air gap is formed between the compensating prism (15) and the fourth surface (134).

7. A waveguide device according to claim 6, wherein: the refractive index of the compensating prism (15) is equal to that of the waveguide substrate.

8. A display system, characterized by: comprising the waveguide device according to any one of claims 1 to 7, and a projector (11) and a lens (12), wherein light emitted from the projector (11) is changed into parallel light by the lens (12) and is incident on the third surface (133).