Super-lens-based near-to-eye display system and AR glasses

Abstract

The invention relates to a near-to-eye display system based on a super lens and AR glasses, and belongs to the technical field of optical devices. The near-to-eye display system comprises a display, a lens group, a polaroid, the super lens and a semi-reflecting and semi-transmitting lens; the display is arranged far away from human eyes and used for loading virtual image information, the lens group is used for forming a 4f system, the polaroid is used for adjusting the polarization state of a light field in a light path, the super lens is used for imaging the virtual information on the retina, and the semi-reflecting and semi-transmitting mirror is arranged close to the human eyes and used for transmitting a virtual scene loaded by the display to the super lens. The near-to-eye display system can realize a wide viewing angle and an eye movement range.

Description

Technical Field

[0001] The present invention belongs to the field of optical devices, and in particular relates to a near-eye display system and AR glasses based on a superlens. Background Art

[0002] Augmented reality (AR) is a technology that integrates computer-generated virtual information into the real world and is considered to be the next generation of display technology. To realize AR, various technologies have been developed to reduce the sense of difference between virtual information and real scenes, thereby providing users with an immersive experience. Among them, transparent near-eye display solutions based on augmented reality glasses (AR glasses) have received widespread attention. In AR glasses, a display placed in front of the human eye produces virtual images and allows users to naturally experience a mixture of virtual information and the real world. In order to achieve transparent near-eye display, a transparent eyepiece is required, which must be able to float the generated image to the desired position in the real scene. To this end, various eyepieces have been proposed, such as those based on spherical mirrors, free-form surface optics, diffractive optical elements (DOEs), and holographic optical elements (HOEs). Their purpose is to realize transparent near-eye displays based on their own optical properties, but due to the limitations of traditional optics, current AR glasses are difficult to provide ultra-wide fields of view (FOV), and their practicality and portability are still challenges.

[0003] To realize the ultimate AR glasses, it is necessary to provide an ultra-wide field of view (FOV), a compact shape, and sufficient eye movement range so that the complete image can be observed in the pupil. Current solutions mostly aim to improve a certain performance. In order to achieve a solution with wide viewing angle and eye movement range, a near-eye display solution based on a superlens is proposed. Summary of the invention

[0004] The present application provides a near-eye display system and AR glasses based on a superlens to at least solve the above technical problems existing in the prior art.

[0005] On the one hand, an embodiment of the present application provides a near-eye display system based on a superlens, including a display, a lens group, a polarizer, a superlens and a semi-reflective half-mirror; the display is arranged away from the human eye and is used to load virtual image information, the lens group is used to form a 4f system, the polarizer is used to adjust the polarization state of the light field in the optical path, the superlens is used to image the virtual information on the retina, and the semi-reflective half-mirror is arranged close to the human eye and is used to transmit the virtual scene loaded by the display to the superlens.

[0006] In one possible implementation manner, there are three polarizers, namely a first polarizer, a second polarizer and a third polarizer, and the polarization states of the first polarizer, the second polarizer and the third polarizer are orthogonal.

[0007] In one possible implementation, the first polarizer is a left-handed polarizer, and the second polarizer and the third polarizer are both right-handed polarizers.

[0008] In one possible implementation, the first polarizer is a right-handed polarizer, and the second polarizer and the third polarizer are both left-handed polarizers.

[0009] In one possible implementation, the lens group includes a first lens and a second lens, and the first lens and the second lens are arranged on both sides of the first polarizer.

[0010] In one possible implementation manner, the superlens and the semi-reflective and semi-transparent mirror are arranged between the second polarizer and the third polarizer.

[0011] In one possible implementation manner, the superlens is disposed on a side close to the third polarizer, and the semi-reflective and semi-transparent mirror is disposed on a side close to the second polarizer.

[0012] In one possible implementation, the design method of the metalens is as follows:

[0013] S1. Determine the parameters of the metalens (diameter D, focal length f and exit pupil distance d) according to the design objectives;

[0014] S2, determining the phase plane of the metalens according to the parameters in S1, truncating the curve at 2π, and dividing the area of ​​the lens into periods;

[0015] S3. Optimize and calculate the nanostructure within each period.

[0016] On the other hand, an embodiment of the present application provides an AR glasses, including any of the above-mentioned near-eye display systems.

[0017] Compared with the prior art, this application has the following advantages:

[0018] 1. This application uses a super lens to achieve a near-eye display solution with a large viewing angle, so that the virtual scene can achieve a larger field of view and eye movement range;

[0019] 2. This application uses an optimization algorithm to achieve imaging of the superlens at multiple wavelengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the structure of a near-eye display system in an embodiment of the present application;

[0021] Figure 2 It is a structural schematic diagram of the super surface optimization model in the embodiment of the present application;

[0022] Figure 3 is a top view of the super surface optimization model in the embodiment of the present application;

[0023] Figure 4It is a schematic diagram of the distribution of lens phase response curves at three RGB wavelengths in an embodiment of the present application;

[0024] Figure 5 This is a schematic diagram of the structural parameters of the metalens in the embodiment of the present application;

[0025] Description of reference numerals:

[0026] 1. Display; 2. Lens group; 21. First lens; 22. Second lens; 3. Polarizer; 31. First polarizer; 32. Second polarizer; 33. Third polarizer; 4. Super lens; 5. Half-reflective half-mirror. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0028] refer to Figure 1 The present application discloses a near-eye display system based on a superlens, which includes a display module and a support structure. The support structure is arranged on the outside of the display module to fix and protect optical elements and increase structural strength.

[0029] The display module includes a display 1, a lens group 2, a polarizer 3, a super lens 4 and a semi-reflective semi-mirror 5. The display 1 is set away from the human eye and is used to load virtual image information. The lens group 2 is used to form a 4f system, which plays the role of imaging and filtering. The polarizer 3 is used to adjust the polarization state of the light field in the optical path. The super lens 4 is used to image the virtual information on the retina. The semi-reflective semi-mirror 5 is set close to the human eye, and the virtual scene loaded by the display is transmitted to the super lens without affecting the real scene entering the human eye. The virtual information is imaged on the retina of the human eye through the super lens, so that the human eye can watch the real and virtual scenes at the same time.

[0030] In this embodiment, the polarizer 3 is composed of three polarizers, namely, a first polarizer 31, a second polarizer 32, and a third polarizer 33, and the polarization states of the first polarizer, the second polarizer, and the third polarizer are orthogonal. That is, when the first polarizer is a left-handed polarizer, the second polarizer and the third polarizer are both right-handed polarizers. That is, when the first polarizer is a right-handed polarizer, the second polarizer and the third polarizer are both left-handed polarizers.

[0031] Taking the first polarizer as a left-handed polarizer as an example, the first polarizer 31 is used to convert the light with virtual image information into right-handed polarized light to match the design characteristics of the metalens. The second polarizer 32 and the third polarizer 33 are both right-handed polarizers, which are used to filter and screen the incident light of the corresponding polarization state.

[0032] In this embodiment, the lens group 2 includes two lenses, namely a first lens 21 and a second lens 22. The first lens 21 and the second lens 22 are respectively arranged on both sides of the first polarizing plate 31 to form a 4f system, which plays the role of imaging and filtering.

[0033] The superlens 4 and the half-reflecting half-mirror 5 are arranged between the second polarizer 32 and the third polarizer 33, wherein the superlens 4 is arranged on the side close to the third polarizer 33, and the half-reflecting half-mirror 5 is arranged on the side close to the second polarizer.

[0034] The display 1 is illuminated by light, and the loaded virtual image information is propagated to the right, converged by the first lens 21, and polarized by the first polarizer 31, and then dispersed by the second lens 22, so as to be transmitted to the semi-reflective semi-transparent mirror 5. The virtual image is propagated to the surface of the super lens 4 after reflection, and the super surface modulates the virtual information in this polarization state and propagates downward. The image information in the real scene is modulated by the second polarizer 32 with the opposite polarization to the first polarizer 31. This polarized light passes through the super lens without modulation and directly merges with the virtual information and passes through the third polarizer 33 to enter the human eye for imaging display.

[0035] Due to the inherent polarization sensitivity of the geometric phase metasurface, the virtual scene carried by the modulated light can be displayed near the eye through design, and the real scene is directly transmitted to achieve the combination of virtual and real scenes. At the same time, the large field of view metalens can make the virtual scene achieve a larger field of view and eye movement range.

[0036] In order to achieve a near-eye display with a large field of view, it is necessary to design a large NA superlens. However, the farther the large NA phase plane is from the center of the lens, the smaller the length required to achieve a phase change from 0 to 2π. Conventional nanocolumn filling schemes cannot guarantee a continuous phase change from 0 to 2π. For this reason, a method such as Figure 2 The optimization scheme shown in Figure 2 is Figure 3 The parameters Lx1Ly1Lx2Ly2ΔxΔyr1r2θ1θ2 shown in the figure are optimized so that the phase of the microstructure in the radial direction changes continuously, and the phase change is only effective for right-handed (or left-handed) polarized light, while left-handed (or right-handed) polarized light is not modulated when passing through the superlens.

[0037] To ensure that the device can work in the visible light band, wavelength optimization is added to the optimization algorithm to ensure that Figure 4 The first-order derivatives of the phase response curves of the metalens at the three RGB wavelengths shown remain equal.

[0038] refer to Figure 5 , the design method of the above-mentioned superlens is as follows:

[0039] S1. Determine the parameters of the metalens (diameter D, focal length f and exit pupil distance d) according to the design objectives;

[0040] S2, determining the phase plane of the metalens according to the parameters in S1, truncating the curve at 2π, and dividing the area of ​​the lens into periods;

[0041] S3. Optimize and calculate the nanostructure within each period.

[0042] Among them, the structure within a single cycle needs to be optimized such as Figure 3 The variables in are set as optimization variables, and the range of parameter values ​​is set to ensure the feasibility of the process and the rationality of the structure. The optimization goal is that the unit can achieve continuous phase change from 0 to 2π, and the phase distribution slope under three wavelengths remains consistent to ensure operation under multiple wavelengths.

[0043] The present application also discloses a pair of AR glasses, comprising any one of the above-mentioned near-eye display systems.

[0044] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A near-eye display system based on a superlens, characterized in that: Including displays, lens groups, polarizers, super lenses and half-reflective half-mirrors; The display is set away from the human eye and is used to load virtual image information. The lens group is used to form a 4f system. Polarizers are used to adjust the polarization state of the light field in the optical path. The super lens is used to image virtual information on the retina. The semi-reflective and semi-mirror lens is placed close to the human eye to transmit the virtual scene loaded by the display to the metalens.

2. A near-eye display system according to claim 1, characterized in that: The polarizers are three, namely a first polarizer, a second polarizer and a third polarizer. The polarization states of the first polarizer, the second polarizer and the third polarizer are orthogonal.

3. A near-eye display system according to claim 2, characterized in that: The first polarizer is a left-handed polarizer, and the second polarizer and the third polarizer are both right-handed polarizers.

4. A near-eye display system according to claim 2, characterized in that: The first polarizer is a right-handed polarizer, and the second polarizer and the third polarizer are both left-handed polarizers.

5. The near-eye display system according to claim 2, characterized in that: The lens group includes a first lens and a second lens, and the first lens and the second lens are arranged on both sides of the first polarizer.

6. A near-eye display system according to claim 2, characterized in that: The super lens and the semi-reflective and semi-transparent mirror are arranged between the second polarizer and the third polarizer.

7. A near-eye display system according to claim 6, characterized in that: The super lens is arranged on a side close to the third polarizer, and the semi-reflective and semi-transparent lens is arranged on a side close to the second polarizer.

8. The near-eye display system according to claim 1, characterized in that: The design method of the metalens is as follows: S1. Determine the parameters of the metalens (diameter D, focal length f and exit pupil distance d) according to the design objectives; S2, determining the phase plane of the metalens according to the parameters in S1, truncating the curve at 2π, and dividing the area of ​​the lens into periods; S3. Optimize the calculation of the nanostructure in each period.

9. An AR glasses, characterized in that: A near-eye display system comprising any one of claims 1-8.

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