Optical engine for near-eye display, and near-eye display device

Abstract

The present disclosure provides an optical engine for near-eye display and a near-eye display device, being related to the technical field of augmented reality and virtual reality. The optical engine for near-eye display comprises a display chip used for emitting image light rays; a metasurface lens assembly, the metasurface lens assembly comprising multiple metasurface lens structures, at least one among the multiple metasurface lens structures being used for receiving image light rays transmitted from the display chip to the surface of the metasurface lens structure; and a deformation piece, wherein the multiple metasurface lens structures are mounted on the deformation piece, and the deformation piece deforms when subjected to an external force or electrified so as to drive the multiple metasurface lens structures connected to the deformation piece to change positions.

Description

Optical engine for near-eye display and near-eye display device

[0001] Cross-references

[0002] This application refers to Chinese Patent Application No. 202311544403.8 filed on November 17, 2023, entitled “Optical Engine and Near-Eye Display Device for Near-Eye Display,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to the technical fields of augmented reality and virtual reality, and in particular to an optical engine for near-eye display and a near-eye display device. Background Art

[0004] Augmented reality (AR) is a technology that uses information provided by computer systems to enhance the user's perception of the real world. It applies virtual information to the real world and superimposes computer-generated virtual objects and scenes onto real scenes, thereby enhancing reality. Virtual reality (VR) uses information provided by computer systems to create a virtual world, such as presenting virtual objects and scenes.

[0005] Near-eye display is a display method used in augmented reality and virtual reality devices, such as glasses or head-mounted displays, which is a display method that is close to the eyes. In addition, the optical engine used for near-eye display is an indispensable part of augmented reality or virtual reality devices. However, the visual convergence and accommodation conflict generated by the augmented reality or virtual reality system can cause dizziness and fatigue in the user (especially when the user wears it for a long time). Therefore, there is a need for an optical engine for near-eye display that can alleviate, reduce or eliminate the visual convergence and accommodation conflict.

[0006] Summary of the Invention

[0007] The present disclosure provides an optical engine for near-eye display and a near-eye display device.

[0008] According to one aspect of the present disclosure, an optical engine for near-eye display is provided, and the optical engine for near-eye display includes: a display chip for emitting image light; a metasurface lens assembly, the metasurface lens assembly including: a plurality of metasurface lens structures, at least one of the plurality of metasurface lens structures being used to receive image light transmitted from the display chip to its surface; and a deformable member, the plurality of metasurface lens structures being mounted on the deformable member, wherein the deformable member deforms when subjected to external force or when energized, so as to drive the plurality of metasurface lens structures connected to the deformable member to change position.

[0009] According to another aspect of the present disclosure, a near-eye display device is provided, including: a carrier; and the optical engine provided above according to the present disclosure, wherein the optical engine is disposed on the carrier.

[0010] According to one or more embodiments of the present disclosure, the display of multiple focal planes can be achieved. Multiple focal planes can provide depth information that is closer to the natural light field to alleviate, reduce or eliminate visual convergence and accommodation conflicts, thereby improving the wearing comfort of augmented reality and virtual reality devices.

[0011] These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments according to the present disclosure and should not be regarded as limiting the scope of the present disclosure.

[0013] 1A-1B are schematic diagrams of an optical engine for near-eye display according to some embodiments of the present disclosure;

[0014] FIG2 is a schematic diagram of a metasurface lens imaging a light beam according to some embodiments of the present disclosure;

[0015] FIG3 is a schematic structural diagram of a liquid lens assembly according to some embodiments of the present disclosure;

[0016] FIG4 is a schematic structural diagram of an electrodeformable body according to some embodiments of the present disclosure;

[0017] FIG5 is a schematic diagram of an optical engine for near-eye display according to some other embodiments of the present disclosure;

[0018] FIG6 is a three-dimensional structural diagram of a near-eye display device according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0019] In this disclosure, unless otherwise specified, the use of terms such as "first" and "second" to describe various elements is not intended to limit the positional relationship, temporal relationship, or importance relationship of these elements. Such terms are only used to distinguish one element from another. In some examples, the first element and the second element may refer to the same instance of the element, while in some cases, based on the context of the description, they may also refer to different instances.

[0020] The terms used in the description of the various examples described in this disclosure are for the purpose of describing specific examples only and are not intended to be limiting. Unless the context clearly indicates otherwise, if the number of elements is not specifically limited, the element can be one or more. As used herein, the term "plurality" means two or more, and the term "based on" should be interpreted as "based at least in part on". In addition, the terms "and / or" and "at least one of..." cover any one of the listed items and all possible combinations.

[0021] Near-eye displays (NEDs) are used to create distant virtual images close to the eye and project them into the human eye. In current optical engines for NEDs, vergence-accommodation conflict is the biggest technical challenge in augmented reality and virtual reality, severely impacting the user experience. Vergence-accommodation conflict refers to the inconsistency between the distance information of the observed object reflected by the human eye's vergence and the lens's accommodation. Vergence refers to the degree of convergence of the eyes when viewing an object with both eyes, while accommodation refers to the lens' adjustment to focus the object, ensuring a clear image is received by the retina. Existing AR and VR devices present images of the same object from different angles to the left and right eyes, using the offset between the images seen by both eyes to create a three-dimensional effect. However, these images lack depth information, resulting in a mismatch between the eye's focus accommodation and depth perception. While vergence still accurately reflects the distance information of the virtual object, this creates a vergence-accommodation conflict. To address this conflict, related technologies propose using multiple focal planes to provide depth information closer to that of natural light, thereby alleviating the vergence-accommodation conflict.

[0022] However, existing multi-focal plane display systems have disadvantages such as complex structure, large size and weight, which are not convenient for the manufacture of augmented reality or virtual reality devices.

[0023] In order to achieve multi-focal plane display while effectively reducing the volume and weight of the optical engine, the present disclosure provides an optical engine for near-eye display.

[0024] Exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0025] 1A-1B are schematic diagrams of an optical engine 100 for near-eye display according to some embodiments of the present disclosure; FIG2 is a schematic diagram of a metasurface lens imaging a light beam according to some embodiments of the present disclosure.

[0026] 1A and 1B , an optical engine 100 for near-eye display includes a display chip 110 and a metasurface lens assembly 120. The display chip 110 is used to emit image light. The metasurface lens assembly 120 includes a plurality of metasurface lens structures 130 and a deformable member 140. At least one of the plurality of metasurface lens structures 130 is used to receive image light transmitted from the display chip 110 to its surface. The plurality of metasurface lens structures 130 are mounted on the deformable member 140. The deformable member 140 deforms when subjected to external force or when energized, so as to cause the plurality of metasurface lens structures 130 connected to the deformable member 140 to change position.

[0027] As shown in Figures 1A and 1B, the display chip 110 is used to generate and modulate two image light groups and transmit the two image light groups to the metasurface lens assembly 120 located downstream of the display chip 110. The deformable member 140 of the metasurface lens assembly 120 in Figure 1A does not deform, while the deformable member 140 of the metasurface lens assembly 120 in Figure 1B deforms, causing the multiple metasurface lens structures 130 connected to the deformable member 140 to also change position. From the comparison of Figures 1A and 1B, it can be seen that due to the position change of the multiple metasurface lens structures 130 in Figure 1B, the incident angles of the image light coupled into some of the multiple metasurface lens structures 130 also change, and thus the exit angles of the image light emitted from these metasurface lens structures 130 change (the image light emitted from the multiple metasurface lens structures 130 in Figure 1B is obviously more concentrated and converged).

[0028] According to some embodiments of the present application, the metasurface lens structure 130 may include a phase compensation structure. The phase compensation structure is formed by a dielectric material. According to some embodiments of the present application, the phase compensation structure may include a solid micro-nanostructure such as a cuboid, a cylinder, or a hemisphere, or a hollow or partially hollow micro-nanostructure having a concave or hole in the shape of a cuboid, a cylinder, or a hemisphere.

[0029] Detailed information regarding the principle of combining multiple metasurface lens structures 130 with a deformable element 140 for use within an optical engine 100 for near-eye display can be found in FIG2 . As shown in FIG2 , the relationship between the phase of image light coupled into the multiple metasurface lens structures 130 (for simplicity, the multiple metasurface lens structures 130 are considered a single structure, represented as the rectangular structure 130 in FIG2 ), the incident angle, and the focal length f is as follows:

[0030]

[0031] Wherein, λ is the wavelength, f is the distance between the sensor 170 and the multiple metasurface lens structures 130 (i.e., the focal length), f' is the distance that the main light of the image light passing through the center point of the multiple metasurface lens structures 130 travels from the multiple metasurface lens structures 130 to the sensor 170, Δr is the distance between one of the multiple metasurface lens structures 130 and the intersection of the main light and the multiple metasurface lens structures 130, and θ=arccos(f / f').

[0032] It can be seen that the focal length f determines the exit angle of the image light emitted from the multiple metasurface lens structures 130, that is, the deflection angle of the exit light. In other words, Relationship 1 can also characterize the relationship between the phase of the incident light, the incident angle of the incident light, the exit angle of the exit light, and the radial distance from the metasurface lens structure 130 to the center point. Therefore, even if the phase of the incident light remains unchanged, the exit angle of the exit light can be changed by changing the incident angle of the incident light or by changing the radial distance from the metasurface lens structure 130 to the center point.

[0033] According to an embodiment of the present disclosure, a plurality of metasurface lens structures 130 are used to realize multi-focal plane display, and are combined with a deformable member 140 (the shape of the deformable member 140 can be changed) and applied to an optical engine of a near-eye display, which can effectively reduce the volume and weight of the optical engine, thereby making the overall structure more compact.

[0034] 1A and 1B , the optical engine 100 may further include an aperture 150 , which is aligned with the metasurface lens assembly 120 and configured to limit image light emitted through the metasurface lens assembly 120 .

[0035] The reason for setting an aperture to limit the image light emitted through the metasurface lens assembly 120 in the optical system is that the image light is often surrounded by stray light. In order to eliminate the influence of stray light on the subsequent optical path, it is necessary to add an aperture in the optical path to block the stray light and allow the main beam of the image light to pass through.

[0036] In the example shown in Figures 1A and 1B, the metasurface lens assembly 120 is located in the emission path of the display chip 110. At least one of the multiple metasurface lens structures 130 is used to receive the image light emitted by the display chip 110, and the multiple metasurface lens structures 130 are mounted on the first side of the deformable member 140, and the first side faces the image light emitted by the display chip 110. In other words, the multiple metasurface lens structures 130 are arranged closer to the display chip 110 than the deformable member 140. Although Figures 1A and 1B show that the multiple metasurface lens structures 130 are mounted on the first side of the deformable member 140, it is understandable that the multiple metasurface lens structures 130 can also be mounted on the second side of the deformable member 140, the second side facing away from the image light emitted by the display chip 110, or the multiple metasurface lens structures 130 can also be mounted on both sides of the deformable member 140, and the present disclosure is not limited to this.

[0037] According to some embodiments of the present application, the position change of the multiple metasurface lens structures 130 includes at least one of the following: at least one metasurface lens structure in the multiple metasurface lens structures 130 is bent or the spacing between at least two metasurface lens structures in the multiple metasurface lens structures 130 changes. In the example shown in Figure 1B, the deformable member 140 of the metasurface lens assembly 120 is bent (convexly bent toward the image light emitted via the display chip 110), and drives the multiple metasurface lens structures 130 connected to the deformable member 140 to also bend. In some embodiments, the change in the spacing between at least two metasurface lens structures in the multiple metasurface lens structures 130 includes at least one of the spacing between at least two metasurface lens structures being enlarged or reduced. As described above, changing the incident angle of the incident light can be achieved by bending the metasurface lens structure, while changing the radial distance of the metasurface lens structure 130 from the center point can be achieved by changing the spacing between at least two metasurface lens structures. In short, the use of the deformable member 140 can change the relative position relationship of the metasurface lens structure 130 (whether bending or spacing change), thereby realizing the zoom imaging function of the optical engine 100.

[0038] According to some embodiments of the present application, the display chip 110 includes at least one of an active light-emitting optical display chip or a passive light-emitting optical display chip. For example, the display chip 110 can be an active light-emitting optical display chip such as Micro LED, Micro OLED, or LCD. For another example, the display chip 110 can also be a passive light-emitting optical display chip such as DLP or LCOS (which requires a light source illumination system to be added to the structure). In some embodiments, the display chip 110 is a chip that can provide monochrome or full-color image information.

[0039] According to some embodiments of the present application, in order to achieve real-time display of multiple focal planes, each focal plane is required to have at least 30 frames of images per second. For example, if n display focal planes are required. For monochrome image display, the image refresh rate of the display chip 110 is required to be at least 30n frames, and the frequency of the deformable member 140 is the same as the frame rate of the display chip 110, both of which are 30n frames. For color display, since the structure of the metasurface lens structure 130 is a function of wavelength, it needs to be displayed separately. At this time, the image refresh rate of the display chip 110 is required to be at least 90n frames, and the frequency of the deformable member 140 is the same as the frame rate of the display chip 110, which is 90n frames. When the frequencies of the display chip 110 and the deformable member 140 are sufficient, infinite multiple focal planes can theoretically be achieved.

[0040] Further reference is made to FIG. 3 . FIG. 3 is a schematic structural diagram of a liquid lens assembly 300 according to some embodiments of the present disclosure. The deformable member 140 may include the liquid lens assembly 300. The liquid lens assembly 300 deforms when subjected to an external force, thereby causing the multiple metasurface lens structures 130 connected to the liquid lens assembly 300 to change position. As shown in FIG. 3 , the liquid lens assembly 300 includes a film 310 and a liquid 320. The film 310 is deformable and light-transmissive, wherein the film 310 encloses a cavity 330. The liquid 320 is filled in the cavity 330.

[0041] In the example shown in FIG3 , a frame 340 is used to respectively secure the upper and lower membranes 310, such that the two membranes 310 enclose a cavity 330 for containing a liquid 320. In some embodiments, an actuator (not shown) may be connected to the liquid lens assembly 300 to contact and compress at least one of the two deformable membranes 310 to deform.

[0042] Although FIG3 shows that the liquid lens assembly 300 may have two films 310 , namely an upper film and a lower film, it is understandable that the liquid lens assembly 300 may also have only one film 310 , namely an upper film or a lower film, and the present disclosure does not limit this.

[0043] According to some embodiments of the present application, film 310 may be an elastic, transparent film capable of arbitrary deformation. In one possible implementation, film 310 may be a PDMS (polydimethylsiloxane) film, although this disclosure does not limit this. According to some embodiments of the present application, liquid 320 may be an optical liquid. When selecting an optical liquid, any desired optical liquid with a specific refractive index and dispersion properties may be selected, provided that the optical liquid does not negatively interact with film 310 (e.g., chemically react with the film). This disclosure does not limit this.

[0044] By wrapping the liquid 320 in the film 310, the liquid lens assembly 300 can be deformed when subjected to external force, thereby causing the multiple metasurface lens structures 130 connected to the liquid lens assembly 300 to also change position. The design concept is ingenious and the structure is compact, so the entire optical engine 100 can be made compact.

[0045] Further reference is made to FIG. 4 . FIG. 4 is a schematic diagram of the structure of an electrodeformer 400 in some embodiments of the present disclosure. The deformable member 140 may include the electrodeformer 400. When energized, the electrodeformer 400 deforms, thereby causing the multiple metasurface lens structures 130 connected to the liquid lens assembly 300 to change position. As shown in FIG. 4 , the electrodeformer 400 includes a piezoelectric block 410 and a wire 420. The wire 420 is used to connect to an external power source to energize the piezoelectric block 410.

[0046] In the example shown in FIG4 , two wires 420 are provided on a piezoelectric block 410, one of which is connected to the positive terminal of a power supply, and the other to the negative terminal of the power supply. A voltage signal is applied to the piezoelectric block 410 via the power supply and wires 420, thereby driving the piezoelectric block 410 to deform.

[0047] Specifically, the deformation effect of piezoelectric block 410 is caused by the rearrangement of the electric dipole moments within the electrotropic material under the influence of an applied electric field. When an external electric field acts on the electrotropic material, the positive and negative charges within the material shift, resulting in the generation of electric dipole moments. These electric dipole moments interact with the applied electric field, causing deformation of the material.

[0048] The piezoelectric block 410 is deformed under the action of an external electric field, which can drive the position change of multiple metasurface lens structures 130 connected to the electrodeformer 400. The design is ingenious and the structure is compact, so the entire optical engine 100 can be compact.

[0049] Further reference is made to FIG. 5 . FIG. 5 is a schematic diagram of an optical engine 500 for near-eye display according to other embodiments of the present disclosure. In some embodiments, the optical engine 500 may further include an optical waveguide 510 . The optical waveguide 510 is used to guide image light emitted by the display chip 110 to the metasurface lens assembly 120 . In some embodiments, the optical engine 500 may further include an optical lens group 520 . The optical lens group 520 is used to shape the image light emitted by the display chip 110 and is opposite to the input end 530 of the optical waveguide 510 , so that the shaped image light can enter the input end 530 of the optical waveguide 510 .

[0050] In the example shown in FIG5 , the optical lens group 520 is disposed in the emission path of the display chip 110. The optical waveguide 510 includes an input end 530 and an output end 540. The input end 530 is disposed in the emission path of the display chip 110 and is used to receive the image light shaped by the optical lens group 520, confine the image light to the channel of the optical waveguide 510 through total internal reflection, and emit the shaped image light at the output end 540. The metasurface lens assembly 120 is opposite to the output end 540 of the optical waveguide 510 to receive the image light emitted from the optical waveguide 510. The metasurface lens assembly 120 includes a plurality of metasurface lens structures 130 and a deformable member 140. At least one metasurface lens structure among the plurality of metasurface lens structures 130 is used to receive the image light emitted from the optical waveguide 510. The plurality of metasurface lens structures 130 are mounted on a first side of the deformable member, with the first side facing the image light emitted from the optical waveguide 510. The deformable member 140 deforms when subjected to external force or when energized, thereby causing the positions of the multiple metasurface lens structures 130 connected to the deformable member 140 to change.

[0051] It should be understood that, in addition to the features described above, other features of the optical engine 500 (e.g., the display chip 110, the metasurface lens assembly 120, etc.) may be the same as the corresponding features of the optical engine 100 described in FIG1A-1B , and for the sake of brevity, they will not be described in detail here.

[0052] Further reference is made to FIG6 . FIG6 is a three-dimensional structural diagram of a near-eye display device 600 according to some embodiments of the present disclosure. As shown in FIG6 , the near-eye display device 600 (for example, augmented reality glasses) includes a carrier 610. The carrier 610 may include a frame 620 and a lens 630. The optical engine 100, 500 may be disposed on the carrier 610. According to some embodiments of the present application, the optical engine 100, 500 may be disposed on the carrier 610 in a laminated manner, or may be disposed within the carrier 610 as an interlayer. The present disclosure does not impose any particular restrictions on the manner in which the optical engine 100, 500 is disposed on the carrier 610.

[0053] The embodiment of the present disclosure manufactures a near-eye display device 600 by adopting a metasurface lens structure in conjunction with a multi-focal plane display system of a deformable part, and arranges the optical engines 100 and 500 on a carrier 610, so that the near-eye display device 600 has a simple structure, a small size and is lightweight, making the near-eye display device 600 similar to the glasses worn by users in daily life, which helps to improve the user experience.

[0054] Although the present disclosure has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative and exemplary and not restrictive; the present disclosure is not limited to the disclosed embodiments. Variations to the disclosed embodiments will be understood and effected by those skilled in the art in practicing the claimed subject matter by studying the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps that are not listed, the indefinite article "a" or "an" does not exclude a plurality, the term "plurality" means two or more, and the term "based on" should be interpreted as "based at least in part on". The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. An optical engine for near-eye display, comprising: Display chip, used to emit image light; A metasurface lens assembly, the metasurface lens assembly comprising: a plurality of metasurface lens structures, at least one of the plurality of metasurface lens structures being used to receive image light transmitted from the display chip to its surface; and A deformable member, wherein the multiple super-surface lens structures are mounted on the deformable member, wherein the deformable member is deformed when subjected to external force or energized, so as to drive the multiple super-surface lens structures connected to the deformable member to change their positions.

2. The optical engine according to claim 1, further comprising: An aperture is aligned with the metasurface lens assembly and is used to limit the image light emitted through the metasurface lens assembly.

3. The optical engine according to claim 1 or 2, wherein: The position change of the multiple super-surface lens structures includes at least one of the following: at least one super-surface lens structure among the multiple super-surface lens structures is bent or the spacing between at least two super-surface lens structures among the multiple super-surface lens structures changes.

4. The optical engine according to claim 1 or 2, wherein: The deformable member includes a liquid lens assembly, and the liquid lens assembly is deformed when subjected to an external force, so as to drive the multiple super-surface lens structures connected to the liquid lens assembly to change their positions.

5. The optical engine according to claim 4, wherein: The liquid lens assembly comprises: A film, the film is deformable and light-transmissive, wherein the film encloses a cavity; and A liquid is filled in the cavity.

6. The optical engine according to claim 1 or 2, wherein: The deformable member includes an electro-deformable body, which deforms when powered on to drive the multiple metasurface lens structures connected to the liquid lens assembly to change their positions.

7. The optical engine according to claim 6, wherein: The electrodeformable body comprises: Piezoelectric blocks; and The wire is used to connect to an external power source to supply power to the piezoelectric block.

8. The optical engine according to claim 1 or 2, characterized in that: The display chip includes at least one of an active light-emitting optical display chip or a passive light-emitting optical display chip.

9. The optical engine according to claim 1 or 2, wherein: The metasurface lens assembly is located in the emission path of the display chip, at least one of the multiple metasurface lens structures is used to receive the image light emitted by the display chip, and the multiple metasurface lens structures are installed on the first side of the deformable member, and the first side faces the image light emitted by the display chip.

10. The optical engine according to claim 1 or 2, further comprising: An optical waveguide is used to guide the image light emitted by the display chip to the metasurface lens assembly.

11. The optical engine according to claim 10, further comprising: The optical lens group is used to shape the image light emitted by the display chip and is opposite to the input end of the optical waveguide so that the shaped image light can enter the input end of the optical waveguide.

12. The optical engine according to claim 11, wherein: The optical lens group is arranged on the emission path of the display chip. The optical waveguide includes an input end and an output end. The input end is arranged in the emission path of the display chip, and is used to receive the image light shaped by the optical lens group, confine the image light in the channel of the optical waveguide through total internal reflection, and emit the shaped image light at the output end. The metasurface lens component is opposite to the output end of the optical waveguide to receive the image light emitted from the optical waveguide, and the metasurface lens component includes: a plurality of metasurface lens structures, at least one of the plurality of metasurface lens structures being used to receive image light emitted from the optical waveguide; and A deformable member, wherein the multiple metasurface lens structures are mounted on a first side of the deformable member, the first side faces the image light emitted from the optical waveguide, wherein the deformable member is deformed when subjected to an external force or energized to drive the multiple metasurface lens structures connected to the deformable member to change their positions.

13. A near-eye display device, characterized in that: include: Carrier; as well as At least one optical engine according to any one of claims 1 to 12, wherein the optical engine is arranged on the carrier.

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