Diffraction optical waveguide and near-to-eye display equipment

Abstract

The utility model discloses a diffraction optical waveguide, which comprises a waveguide substrate, the waveguide substrate at least comprises a coupling-in area, a first coupling-out area and a second coupling-out area, and the first coupling-out area and the second coupling-out area are respectively used for corresponding to a left eye and a right eye of a human eye, the first coupling-out area, the coupling-in area and the second coupling-out area are sequentially arranged in the first direction, and the size of the coupling-in area in the first direction is matched with the size of a projection light spot on a coupling-in plane in the first direction. The size of the coupling-in area in the second direction is larger than the size of a projection light spot on the coupling-in plane in the second direction, and the first direction is orthogonal to the second direction. The diffraction optical waveguide provided by the utility model can be compatible with an optical machine installation position in a certain range.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of augmented reality, and in particular to a diffractive optical waveguide and a near-eye display device. BACKGROUND

[0002] Augmented reality is a technology of fusing the real world and virtual information, and an augmented reality display system usually comprises a micro projector and an optical display screen. The micro projector provides virtual display content for the augmented reality display system to project into the human eye through the optical display screen. The optical display screen is usually a transparent optical component, so that the user can also see the real world through the optical display screen.

[0003] The diffractive optical waveguide of the prior art has different designs in appearance, and the position of the light machine is different under different designs. The position of the coupling-in region is closely related to the position of the light machine. The design of the grating architecture of the diffractive optical waveguide needs to be performed separately under each appearance, which is not universal and has high cost. CONTENT OF THE UTILITY MODEL

[0004] The embodiment of the present application provides a diffractive optical waveguide and a near-eye display device, wherein the size of the coupling-in region of the diffractive optical waveguide in one direction is greater than the size of the projected light spot on the coupling-in plane, which can be compatible with a certain range of light machine installation positions in the direction, and has stronger universality and lower cost.

[0005] The embodiment of the present application provides a diffractive optical waveguide, comprising:

[0006] A waveguide substrate, the waveguide substrate at least comprises a coupling-in region, a first coupling-out region and a second coupling-out region, the first coupling-out region and the second coupling-out region are respectively used for corresponding left eye and right eye of a human eye, the first coupling-out region, the coupling-in region and the second coupling-out region are sequentially arranged in a first direction, the size of the coupling-in region in the first direction matches the size of a projected light spot on a coupling-in plane in the first direction, the size of the coupling-in region in a second direction is greater than the size of the projected light spot on the coupling-in plane in the second direction, and the first direction is orthogonal to the second direction.

[0007] In an embodiment, the first coupling-out region and the second coupling-out region are mirror symmetric about the coupling-in region, and the coupling-in grating structure in the coupling-in region is mirror symmetric about the central axis of the coupling-in region.

[0008] In an embodiment, the coupling-in grating structure is a one-dimensional grating structure, comprising a first coupling-in grating and a second coupling-in grating with different grating vector directions.

[0009] In an embodiment, the first out-coupling region comprises at least three sub-regions, one of which is a two-dimensional out-coupling grating, and the other two are one-dimensional out-coupling gratings, which are arranged on both sides of the two-dimensional out-coupling grating in the second direction.

[0010] In an embodiment, the size of the in-coupling region in the first direction ranges from 4 to 4.4 mm.

[0011] In an embodiment, the size of the in-coupling region in the second direction ranges from 6 to 10 mm.

[0012] In an embodiment, the distance between the center of the first out-coupling region and the center of the in-coupling region in the first direction ranges from 30 to 36 mm.

[0013] In an embodiment, the distance between the center of the first out-coupling region and the center of the in-coupling region in the second direction ranges from 6 to 12 mm.

[0014] In an embodiment, the in-coupling region is in the shape of a capsule.

[0015] In an embodiment, the first out-coupling region and the second out-coupling region are both polygons.

[0016] The embodiments of the present application also provide a near-eye display device, which comprises the diffractive optical waveguide and the optical engine as described in any one of the preceding embodiments.

[0017] In an embodiment, the distance y between the intersection of the optical axis of the optical engine and the in-coupling region and the center of the first out-coupling region in the second direction satisfies the following formula:

[0018] y = y eyebox + e y e r e l i e f * tan θ

[0019] wherein y eyebox is the distance between the center of the eyebox and the center of the first out-coupling region in the second direction, eyerelief is the eye relief, and θ is the incident angle of the optical engine.

[0020] This application provides a diffractive waveguide and a near-eye display device, wherein the diffractive waveguide includes at least an insertion region, a first output region, and a second output region. The first output region and the second output region are respectively used for the left and right eyes of a human eye, and the first output region, insertion region, and second output region are arranged sequentially in a first direction. Specifically, the size of the insertion region in the first direction matches the size of the projected light spot on the insertion plane in the first direction, but the size of the insertion region in the second direction is larger than the size of the projected light spot on the insertion plane in the second direction. This allows for compatibility with a certain range of optomechanical mounting positions in the second direction, making the diffractive waveguide more versatile and reducing costs. Furthermore, the increase in the size of the insertion region does not occur on the original effective optical path, thus not affecting the transmission of light in the first direction after insertion. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A schematic diagram of a diffractive waveguide provided in an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of another diffractive waveguide structure provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application;

[0025] Attached image labels:

[0026] 100: Diffractive waveguide;

[0027] 110: Coupling region; 111: First coupling grating; 112: Second coupling grating;

[0028] 120: First coupling region;

[0029] 130: Second coupling region;

[0030] 140: Waveguide substrate;

[0031] 200: Optical engine. Detailed Implementation

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0033] The technical solutions of the present application will be described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in some embodiments.

[0034] The present application provides a diffractive optical waveguide, which comprises a waveguide substrate, the waveguide substrate at least comprising a coupling-in region, a first coupling-out region and a second coupling-out region, the first coupling-out region and the second coupling-out region being respectively used for corresponding left eye and right eye of a human eye, the first coupling-out region, the coupling-in region and the second coupling-out region being arranged in sequence in a first direction, a size of the coupling-in region in the first direction matching a size of a projected light spot on a coupling-in plane in the first direction, a size of the coupling-in region in a second direction being greater than a size of the projected light spot on the coupling-in plane in the second direction, the first direction being orthogonal to the second direction.

[0035] Specifically, the diffractive optical waveguide provided by the present application is used for binocular display. After the image light rays emitted by an optical engine are incident on the coupling-in region, a part of the image light rays are coupled into the waveguide substrate by the coupling-in structure in the coupling-in region and totally reflected and transmitted toward the first coupling-out region, and after the part of the image light rays are transmitted to the first coupling-out region, the image light rays are coupled out into the left eye by the coupling-out structure; a part of the image light rays are coupled into the waveguide substrate by the coupling-in structure in the coupling-in region and totally reflected and transmitted toward the second coupling-out region, and after the part of the image light rays are transmitted to the second coupling-out region, the image light rays are coupled out into the right eye by the coupling-out structure, so that binocular display is realized by one optical engine.

[0036] The optical engine is used for projecting light rays with image information in a predetermined field of view range. The optical engine in the present application can adopt different types of optical engines such as uLED, LCOS, DLP, LBS, OLED, etc. The waveguide substrate is used for totally reflecting and transmitting the image light rays. The waveguide substrate in the present application can adopt materials with good optical characteristics such as resin, glass, silicon carbide, etc. Both the coupling-in structure and the coupling-out structure can adopt geometric optical elements or diffractive optical elements. The coupling-in structure and the coupling-out structure in the present application can adopt elements such as diffraction gratings.

[0037] Exemplarily, reference is made to Figure 1For example, taking the spatial rectangular coordinate system as an example, taking the coupling-in plane of the diffractive optical waveguide 100 as the XOY plane, the first direction as the X-axis direction and the second direction as the Y-axis direction. The diffractive optical waveguide 100 comprises a coupling-in region 110, a first coupling-out region 120 and a second coupling-out region 130. The first coupling-out region 120, the coupling-in region 110 and the second coupling-out region 130 are arranged in sequence in the X-axis direction.

[0038] It can be understood that the present application is made in view of the technical prejudice existing in the current field of display technology based on diffractive optical waveguide. Specifically, in order to enable the coupling-in structure to receive as many image light rays from the light engine as possible so as to improve the light utilization efficiency of the diffractive optical waveguide, it is obviously formed in the prior art that the situation that the coupling-in structure causes field-of-view loss and light leakage when receiving the image light rays from the light engine should be avoided, and accordingly the general view that the size of the coupling-in structure should be comparable to the projected light spot on the coupling-in plane and the optical axis of the light engine should be aligned with the center of the coupling-in structure is formed. However, the present application breaks this technical prejudice, and particularly designs the size of the coupling-in region in the second direction to be greater than the size of the projected light spot on the coupling-in plane in the second direction, without affecting the original effective light propagation path; and no longer requires the optical axis of the light engine to be aligned with the center of the coupling-in structure, so as to be able to adapt to more light engine positions and diffractive optical waveguide shapes. That is, as can be seen from Figure 1 , the size of the coupling-in region 120 in the Y-axis direction is expanded, which is obviously greater than the size of the coupling-in region 120 in the X-axis direction.

[0039] For example, continuing to refer to Figure 1 , where it is defined that the size of the coupling-in region 110 in the first direction is L1, the size of the coupling-in region 110 in the second direction is L2, the distance between the center position of the first coupling-out region 120 and the center position of the coupling-in region 110 in the first direction is L3, and the distance between the center position of the first coupling-out region 120 and the center position of the coupling-in region 110 in the second direction is L4.

[0040] For implementation, the size of the coupling-in region in the first direction ranges from 4-4.4 mm. Specifically, the size of the coupling-in region in the first direction should match the size of the projected light spot on the coupling-in plane in the first direction, so as to avoid the problem of field-of-view loss caused by the small size of the coupling-in region or the problem of light leakage caused by the large size of the coupling-in region.

[0041] For implementation, the size of the coupling-in region in the second direction ranges from 6-10 mm. Specifically, the size of the coupling-in region in the second direction is expanded so as to adapt to more light engine positions and diffractive optical waveguide shapes; however, the size of the coupling-in region in the second direction should not be too large, limited by the actual product application environment of the diffractive optical waveguide and the demand for ergonomics.

[0042] In an embodiment, the distance between the center of the first out-coupling region and the center of the in-coupling region in the first direction is in the range of 30-36mm. Generally, the distance between the center of the first out-coupling region and the center of the second out-coupling region in the first direction is adapted to the interpupillary distance of the human eye. When the first out-coupling region and the second out-coupling region are mirror-symmetric about the in-coupling region, the distance between the center of the first out-coupling region and the center of the in-coupling region in the first direction is about half of the interpupillary distance. It can be understood that different people have different interpupillary distances, and therefore an appropriate range should be selected.

[0043] In an embodiment, the distance between the center of the first out-coupling region and the center of the in-coupling region in the second direction is in the range of 6-12mm.

[0044] In an embodiment, the in-coupling region is capsule-shaped.

[0045] In an embodiment, the first out-coupling region and the second out-coupling region are both polygons.

[0046] Exemplarily, with reference to Figure 1 and Figure 2 It can be seen that the shape of the in-coupling region 110 is capsule-shaped, with two semicircular ends and a rectangular middle. The first out-coupling region 120 and the second out-coupling region 130 are quadrilaterals.

[0047] In this embodiment, the first out-coupling region 120 and the second out-coupling region 130 are irregular quadrilaterals. The size of the two out-coupling regions in the first direction gradually decreases as they move away from the in-coupling region 110. The part of the region that changes in size is a pre- expansion region of the out-coupling region, which is beneficial to improving the uniformity of the out-coupling region.

[0048] In some embodiments, the first out-coupling region and the second out-coupling region are mirror-symmetric about the in-coupling region. In the case of a symmetric design, the amount of optimization calculation can be reduced, the efficiency can be improved, and the research and development cycle can be shortened. Of course, in other embodiments, the in-coupling region can also be arranged close to one of the first out-coupling region and the second out-coupling region. In this case, the center line between the center of the first out-coupling region and the center of the second out-coupling region is substantially a horizontal line, so as to avoid differences between the images of the left eye and the right eye.

[0049] In a further embodiment, the in-coupling grating structure in the in-coupling region is mirror-symmetric about the central axis of the in-coupling region. Specifically, the in-coupling grating structure in the in-coupling region can adopt a symmetric tooth-shaped structure, such as a straight-tooth structure, an isosceles trapezoidal structure, etc. In this case, among the diffracted light transmitted towards the first out-coupling region and the diffracted light transmitted towards the second out-coupling region, one is -1 order diffracted light and the other is +1 order diffracted light. The grating diffraction characteristics of the symmetric tooth-shaped structure are equal for ±1 order diffraction efficiency, which is helpful to the consistency of the display picture effect of the left eye and the right eye. Moreover, in this embodiment, the ±1 order diffraction of the in-coupling grating structure is utilized, which effectively improves the light energy utilization rate.

[0050] In addition, the in-coupling grating structure can be a one-dimensional grating structure, which includes a first in-coupling grating and a second in-coupling grating with different grating vector directions.

[0051] Specifically, the in-coupling grating in the in-coupling region is a one-dimensional grating with two grating vectors at an angle, and the grating structure can be a blazed grating, a skew grating or other asymmetric structures, which can have high in-coupling efficiency and can increase the freedom of the waveguide shape due to the relative position of the grating.

[0052] For example, referring to Figure 2 , the in-coupling region 110 includes a first in-coupling grating 111 and a second in-coupling grating 112, and the grating vector directions of the first in-coupling grating 111 and the second in-coupling grating 112 are different.

[0053] In an embodiment, the first out-coupling region includes at least three sub-regions, one of which is a two-dimensional out-coupling grating, and the other two are one-dimensional out-coupling gratings, and the one-dimensional out-coupling gratings are arranged on both sides of the two-dimensional out-coupling grating in the second direction.

[0054] In this application, the out-coupling region is divided into sub-regions, and the combination of one-dimensional gratings and two-dimensional gratings is used, which can improve the efficiency and uniformity of the diffractive optical waveguide. The multiple sub-regions can be arranged in a regular manner, for example, each sub-region can be a rectangular sub-region with the same size, or a sub-region with the same size and other suitable shape, or the multiple sub-regions can be arranged in an irregular manner, and can have sub-regions with different sizes and / or shapes.

[0055] The embodiments of the present application also provide a near-eye display device, which includes the diffractive optical waveguide and the optical machine according to any one of the preceding embodiments.

[0056] In an embodiment, the distance y between the intersection of the optical axis of the optical machine and the in-coupling region and the center position of the first out-coupling region in the second direction satisfies the following formula:

[0057] y=y eyebox +eyerelief*tanθ

[0058] wherein y eyebox is the distance between the center of the eyebox and the center position of the first out-coupling region in the second direction, eyerelief is the eye relief, and θ is the incident angle of the optical machine.

[0059] Specifically, in general, when designing a diffractive optical waveguide, the effective size of the out-coupling region is first determined according to the user's view parameters, and then the position of the out-coupling region is determined according to the position of the eyebox in space. Then, according to the preset incident angle of the optical machine, the intersection position of the optical axis of the optical machine and the in-coupling region, i.e. the irradiation position of the optical machine, can be determined according to the above formula.

[0060] For example, refer to Figure 3 Image rays emitted from the optomechanism 200 are incident on the coupling region 110. The incident angle of the optomechanism is θ. In this figure, the incident direction is clockwise within the ZOY plane, so the value of θ should be negative. In another embodiment, the incident direction is counterclockwise within the ZOY plane, so the value of θ should be positive.

[0061] The diffractive waveguide and near-eye display device provided in this application include at least an insertion region, a first output region, and a second output region. The first output region and the second output region are respectively used for the left and right eyes of the human eye, and the first output region, insertion region, and second output region are arranged sequentially in a first direction. Specifically, the size of the insertion region in the first direction matches the size of the projected light spot on the insertion plane in the first direction, but the size of the insertion region in the second direction is larger than the size of the projected light spot on the insertion plane in the second direction. This allows for compatibility with a certain range of optomechanical mounting positions in the second direction, making the diffractive waveguide more versatile and reducing costs. Furthermore, the increase in the size of the insertion region does not occur on the original effective optical path, thus not affecting the transmission of light in the first direction after insertion.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A diffractive optical waveguide, characterized by, The diffractive optical waveguide comprises: a waveguide substrate comprising at least a coupling-in region, a first coupling-out region and a second coupling-out region, the first and second coupling-out regions being for corresponding to a left eye and a right eye of a human eye respectively, the first coupling-out region, the coupling-in region and the second coupling-out region being arranged in a first direction in sequence, a size of the coupling-in region in the first direction matching a size of a projected light spot on a coupling-in plane in the first direction, a size of the coupling-in region in a second direction being greater than a size of the projected light spot on the coupling-in plane in the second direction, the first direction being orthogonal to the second direction.

2. The diffractive optical waveguide of claim 1, wherein, The first and second coupling-out regions are mirror-symmetric about the coupling-in region, and a coupling-in grating structure in the coupling-in region is mirror-symmetric about a central axis of the coupling-in region.

3. The diffractive optical waveguide of claim 2, wherein, The coupling-in grating structure is a one-dimensional grating structure, comprising a first coupling-in grating and a second coupling-in grating with different grating vector directions.

4. The diffractive optical waveguide of claim 2, wherein, The first coupling-out region comprises at least three sub-regions, one of which is a two-dimensional coupling-out grating, and the other two are one-dimensional coupling-out gratings, the one-dimensional coupling-out gratings being arranged on both sides of the two-dimensional coupling-out grating in the second direction.

5. The diffractive optical waveguide of claim 1, wherein, The size of the coupling-in region in the first direction ranges from 4 to 4.4 mm, and the size of the coupling-in region in the second direction ranges from 6 to 10 mm.

6. The diffractive optical waveguide of claim 3, wherein, The distance between the center of the first coupling-out region and the center of the coupling-in region in the first direction ranges from 30 to 36 mm, and / or the distance between the center of the first coupling-out region and the center of the coupling-in region in the second direction ranges from 6 to 12 mm.

7. The diffractive optical waveguide of claim 1, wherein, The coupling-in region is in the shape of a capsule.

8. The diffractive optical waveguide of claim 1, wherein, The first and second coupling-out regions are both polygons.

9. A near-eye display device, comprising: The near-eye display device comprises the diffractive optical waveguide and an optical engine as claimed in any one of claims 1-8.

10. The near-eye display device of claim 9, wherein, The distance y between the intersection of the optical axis of the optical engine and the coupling-in region and the center of the first coupling-out region in the second direction satisfies the following formula: y = y eyebox + e y relief * tan θ where y eyebox is the distance between the center of the window and the center of the first out-coupling region in the second direction, eyerelief is the eye relief, and θ is the angle of incidence of the light engine.

Images