Large-view-field compact eyepiece lens for near-to-eye display and near-to-eye display device

Abstract

The invention discloses a large-view-field compact eyepiece lens for near-to-eye display and a near-to-eye display device. The large-view-field compact eyepiece lens comprises an image source, a first optical lens, a second optical lens, a third optical lens, a fourth optical lens and an optical prism, light is emitted from an image source, sequentially penetrates through the first optical lens and then enters the optical prism, and is refracted and reflected by the interior of the optical prism for multiple times: firstly, the light is reflected back to the optical prism through the second surface of the third optical lens, then is reflected by the second surface of the second optical lens, and finally is output through the optical prism and penetrates through the fourth optical lens to be emitted; the optical prism is compact in structure, optical path folding is achieved, and the length of an optical system is effectively shortened. According to the eyepiece lens, the field angle is 50 degrees, the length of an optical system can be shortened by at least 20%, the imaging definition is high, and the structure is compact.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to a large-field-of-view compact eyepiece lens for near-eye display and a near-eye display device. Background Art

[0002] Near-eye display optical system is also called helmet display. Based on augmented reality, near-eye display system can superimpose virtual images while people are watching the surrounding environment, so as to obtain more visual information. Near-eye display helmet display was first used in the military field. With the advancement of science and technology and the development of society, it has gradually expanded to various fields such as industry, entertainment, and medical treatment. People are also doing more and more research on near-eye display.

[0003] Since the waveguide has the advantages of being thin and light in appearance and closer in size to ordinary glasses, the near-eye display system based on optical waveguide has become one of the mainstream solutions for development. As an important component of the near-eye display system, the imaging quality and volume size of the eyepiece lens directly affect the image clarity and wearing comfort of the user, and the larger the field of view, the better the immersive experience. However, due to the optical path limitations of the traditional architecture, the field of view and volume size are irreconcilable contradictions, which has a great impact on the experience of near-eye display products. In addition, most of the multiple reflection optical solutions on the market use semi-transparent and semi-reflective films, which seriously lose light energy. This solution requires the display screen to have a high luminous brightness. Summary of the invention

[0004] Technical purpose: In view of the shortcomings of existing eyepiece lenses and near-eye display devices, the present invention discloses a large-field-of-view compact eyepiece lens and a near-eye display device for near-eye display. By rationally planning the position of light reflection and using multiple reflections, the system optical path is folded, which not only avoids the loss of light energy, but also enables the eyepiece lens to meet the requirements of large field of view and small volume.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A large-field-of-view compact eyepiece lens for near-eye display, comprising an image source, a first optical lens, a second optical lens, a third optical lens, a fourth optical lens and an optical prism; the image source is located on the second surface side of the first optical lens and is used to output image light; the second surface of the second optical lens and the second surface of the third optical lens are both reflective surfaces and are used to fold and reflect light; the fourth optical lens is used to output the reflected light; the optical prism has a plurality of optical surfaces, and the plurality of optical surfaces are respectively bonded to the first optical lens, the second optical lens, the third optical lens and the fourth optical lens; The light output by the image source passes through the first optical lens in sequence and enters the optical prism, is reflected by the second surface of the third optical lens, returns to the optical prism, is reflected by the second surface of the second optical lens, and finally is emitted through the optical prism and the fourth optical lens.

[0006] Preferably, the multiple optical surfaces are respectively a first optical surface, a second optical surface, a third optical surface and a fourth optical surface, wherein the angle a between the first optical surface and the fourth optical surface satisfies: 80°≤a≤100°; the angle b between the first optical surface and the second optical surface satisfies: 100°≤b≤120°; the angle c between the third optical surface and the fourth optical surface satisfies: 100°≤c≤120°.

[0007] Preferably, the effective focal length of the second optical lens and the effective focal length of the eyepiece lens satisfy: 1.1≤f2 / f≤1.5, wherein f2 is the effective focal length of the second optical lens, and f is the effective focal length of the eyepiece lens.

[0008] Preferably, the effective focal length of the third optical lens and the effective focal length of the eyepiece lens satisfy: 2.5 ≤ f3 / f ≤3, wherein f3 is the effective focal length of the third optical lens, and f is the effective focal length of the eyepiece lens.

[0009] Preferably, the effective focal length of the first optical lens satisfies: |f1|≥100; the effective focal length of the fourth optical lens satisfies: |f4|≥100.

[0010] Preferably, the surface shape of the first surface of the first optical lens and the second surface of the fourth optical lens is any one of an even-order aspheric surface, a polynomial, an extended polynomial or a Zernike standard vector high.

[0011] Preferably, the surface shapes of the second surface of the second optical lens and the second surface of the third optical lens include any one of a standard surface or an even-order aspherical surface.

[0012] Preferably, the surfaces of the first optical lens, the second optical lens, the third optical lens and the fourth optical lens that are in contact with the optical prism are all planes.

[0013] A near-eye display device comprises an image source, an eyepiece lens and a waveguide, wherein the eyepiece lens is a large-field compact eyepiece lens for near-eye display as described above, and the image source is used to output image light; the eyepiece lens is arranged on a side where the image source outputs image light, and is used to change the optical path of the image light; the waveguide is arranged at the light emitting end of the eyepiece lens, and is used to transmit the light emitted by the eyepiece lens.

[0014] Preferably, the image source comprises any one of a liquid crystal on silicon display, an organic light emitting diode, and a micro light emitting diode; and the waveguide sheet is at least one of a geometric light waveguide or a diffraction light waveguide.

[0015] Beneficial effects: The large-field-of-view compact eyepiece lens and near-eye display device provided by the present invention have the following beneficial effects: The present invention folds the system light path through multiple refraction and reflection path designs of the optical prism, combined with the reasonable layout of the first optical lens, the second optical lens, the third optical lens and the fourth optical lens. Since no semi-transparent and semi-reflective film layer is required in the system, no light energy is lost, and it has the advantage of high light efficiency. Since the system light path is folded by multiple reflections, the overall length of the optical system is effectively compressed, a compact optical structure is achieved, and a large field of view and a small volume of the eyepiece lens can be achieved. When the field of view angle is 50°, the length of the eyepiece lens designed using this solution can be shortened by at least 20%.

[0016] The second surfaces of the first optical lens and the fourth optical lens of the present invention both adopt a free-form surface design, which effectively corrects aberrations and improves the clarity and uniformity of imaging; the second surfaces of the second optical lens and the third optical lens adopt an even-order aspheric surface or a spherical surface with a simple surface shape, which relaxes the tolerance requirements for eccentricity and tilt during processing and assembly, and improves the production yield.

[0017] The optical prism is fitted with each optical lens through the optical surface. The optical path is fixed and the angle between the reflective surfaces is reasonably designed, ensuring that the light has high stability and low loss during the reflection and refraction process, thereby improving the optical performance of the system. At the same time, each optical surface is designed to be flat, which simplifies the manufacturing and assembly process of optical components, helps to reduce production costs, and improve the efficiency and consistency of mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0019] Figure 1 A schematic diagram of the structure of a compact eyepiece lens with a large field of view for near-eye display provided by the present invention; Figure 2 A schematic structural diagram of a near-eye display device provided by the present invention; Figure 3 A schematic diagram of light rays of a compact eyepiece lens with a large field of view for near-eye display provided in an embodiment; Figure 4 A transfer function curve diagram of a large field of view compact eyepiece lens for near-eye display provided by an embodiment; Figure 5A field curvature distortion diagram of a large field of view compact eyepiece lens for near-eye display provided in an embodiment.

[0020] In the figure: 00, image source; 01, first optical lens; 11, second surface of the first optical lens; 02, second optical lens; 21, second surface of the second optical lens; 03, third optical lens; 31, second surface of the third optical lens; 04, fourth optical lens; 41, second surface of the fourth optical lens; 05, optical prism; 51, first optical surface; 52, second optical surface; 53, third optical surface; 54, fourth optical surface; 100, eyepiece lens; 200, waveguide. DETAILED DESCRIPTION

[0021] The present invention will be described more clearly and completely below by way of a preferred embodiment in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiment.

[0022] like Figure 1 As shown, a large-field-of-view compact eyepiece lens for near-eye display comprises an image source 00, a first optical lens 01, a second optical lens 02, a third optical lens 03, a fourth optical lens 04 and an optical prism 05; the image source 00 is located on the second surface 11 side of the first optical lens, and is used to output image light, and the first optical lens 01 is used to receive light from the image source 00; the second surface 31 of the third optical lens is a reflective surface, and is used to perform a first folding reflection on the light; the second surface 21 of the second optical lens is a reflective surface, and is used to perform a second folding reflection on the light; the fourth optical lens 04 is used to output the reflected light, and the optical prism 05 has a plurality of optical surfaces, and the plurality of optical surfaces are respectively correspondingly bonded to the first optical lens 01, the second optical lens 02, the third optical lens 03 and the fourth optical lens 04; The light output by the image source 00 passes through the first optical lens 01 and enters the optical prism 05 in sequence. The light enters the third optical lens 03 through the third optical surface 53 of the optical prism 05, is reflected by the second surface 31 of the third optical lens, and then returns to the optical prism 05. At this time, the light enters the second optical lens 02 through the second optical surface 52 of the optical prism 05, is reflected 21 by the second surface of the second optical lens, and finally is emitted through the optical prism 05 and the fourth optical lens 04 to achieve imaging.

[0023] In one embodiment of the present invention, the multiple optical surfaces are respectively a first optical surface 51, a second optical surface 52, a third optical surface 53 and a fourth optical surface 54, wherein the angle a between the first optical surface 51 and the fourth optical surface 54 satisfies: 80°≤a≤100°; the angle b between the first optical surface 51 and the second optical surface 52 satisfies: 100°≤b≤120°; the angle c between the third optical surface 53 and the fourth optical surface 54 satisfies: 100°≤c≤120°.

[0024] The angles between the surfaces of the optical prism are precisely calculated and designed to ensure that the reflection and refraction of light inside the prism can efficiently fold the light path, shorten the overall length of the optical system, while maintaining the stability of optical performance and imaging quality.

[0025] In one embodiment of the present invention, the effective focal length of the second optical lens 02 and the effective focal length of the eyepiece lens satisfy: 1.1≤f2 / f≤1.5, where f2 is the effective focal length of the second optical lens, and f is the effective focal length of the eyepiece lens.

[0026] The effective focal length of the third optical lens 03 and the effective focal length of the eyepiece lens satisfy: 2.5 ≤ f3 / f ≤3, where f3 is the effective focal length of the third optical lens, and f is the effective focal length of the eyepiece lens.

[0027] The effective focal length of the first optical lens 01 satisfies: |f1|≥100; the effective focal length of the fourth optical lens 04 satisfies: |f4|≥100.

[0028] In one embodiment of the present invention, the surface shapes of the first surface 11 of the first optical lens and the second surface 41 of the fourth optical lens are any one of an even-order aspheric surface, a polynomial, an extended polynomial or a Zernike standard vector high, which is beneficial to improving the imaging quality of the entire optical system and ensuring that the image is clear and distortion-free.

[0029] The surface shapes of the second surface 21 of the second optical lens and the second surface 31 of the third optical lens include either a standard surface or an even-order aspheric surface. The use of the above mirrors can optimize the path of light during the reflection process, reduce distortion, and further improve the imaging quality of the optical system.

[0030] The surfaces of the first optical lens 01, the second optical lens 02, the third optical lens 03 and the fourth optical lens 04 that are in contact with the optical prism 05 are all flat, which helps to simplify the manufacturing and assembly processes, reduce manufacturing costs, and ensure the stability of light transmission between each lens and the optical prism.

[0031] A near-eye display device includes an image source 00, an eyepiece lens 100 and a waveguide 200. The eyepiece lens 100 is a large-field compact eyepiece lens for near-eye display as described above. The image source 00 is used to output image light. The eyepiece lens 100 is arranged on a side where the image source 00 outputs image light, and is used to change the optical path of the image light. The waveguide 200 is arranged at the light emitting end of the eyepiece lens 100, and is used to transmit the light emitted by the eyepiece lens.

[0032] The image source 00 includes any one of a liquid crystal on silicon display, an organic light emitting diode, and a micro light emitting diode; the waveguide plate 200 is at least one of a geometric optical waveguide or a diffraction optical waveguide.

[0033] Embodiment 1

[0034] In this embodiment, a 0.65-inch silicon-based OLED with an aspect ratio of 16:9 is taken as an example, an optical system with a FOV of 50° is designed, and an initial optical path is built and optimized according to the above optical structure.

[0035] The surface types of the first surface 11 of the first optical lens and the second surface 41 of the fourth optical lens include: even-order aspheric surface, polynomial, extended polynomial, Zernike standard sagittal height, etc. In this embodiment, an extended polynomial surface is used, and the surface sagittal height is defined as follows:

[0036] in, is the vector height, N is the total number of polynomial coefficients in the series, is the coefficient of the i-th expanded polynomial, which is just a power series in the x and y directions.

[0037] Among them, the angle a between the first optical surface 51 and the fourth optical surface 54 of the optical prism 05 satisfies: 80°≤a≤100°; the angle b between the first optical surface 51 and the second optical surface 52 of the optical prism satisfies: 100°≤b≤120°; the angle c between the third optical surface 53 and the fourth optical surface 54 of the optical prism satisfies: 100°≤c≤120°.

[0038] like Figure 2 A schematic structural diagram of a near-eye display device provided by the present invention includes an image source 00, an eyepiece lens 100 and a waveguide 200. The eyepiece lens 100 is a large-field compact eyepiece lens for near-eye display as described above. The image source 00 is used to output image light. The eyepiece lens 100 is arranged on a side where the image source 00 outputs image light, and is used to change the optical path of the image light. The waveguide 200 is arranged at the light emitting end of the eyepiece lens, and is used to transmit the light emitted by the eyepiece lens.

[0039] like Figure 3The figure shows a light schematic diagram of a large-field-of-view compact eyepiece lens for near-eye display provided in this embodiment. From the figure, it can be seen that the light is emitted after two reflections in the optical path, and the two reflections fold the optical path. The length of the eyepiece lens designed in this embodiment is less than 23 mm, which is at least 20% shorter than the length of the traditional design.

[0040] like Figure 4 The transfer function curve of a large field of view compact eyepiece lens for near-eye display provided by this embodiment is shown. The transfer function (MTF) characterizes the imaging quality of the system. The higher the MTF, the better the imaging quality. Figure 4 It can be seen that the full field of view MTF@40lp / mm>0.2, which meets the viewing needs of the human eye; Figure 5 The figure shows the field curvature distortion diagram of a large-field-of-view compact eyepiece lens for near-eye display provided by this embodiment. From the figure, it can be seen that the maximum distortion is 3.147%, and the human eye will not feel obvious distortion when viewing.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A large-field-of-view compact eyepiece lens for near-eye display, characterized in that: It includes an image source, a first optical lens, a second optical lens, a third optical lens, a fourth optical lens and an optical prism; the image source is located on the first surface side of the first optical lens and is used to output image light; the second surface of the second optical lens and the second surface of the third optical lens are both reflective surfaces and are used to fold and reflect the light; the fourth optical lens is used to output the reflected light; the optical prism has a plurality of optical surfaces, and the plurality of optical surfaces are respectively correspondingly bonded to the first optical lens, the second optical lens, the third optical lens and the fourth optical lens; The light output by the image source passes through the first optical lens in sequence and enters the optical prism, is reflected by the second surface of the third optical lens, returns to the optical prism, is reflected by the second surface of the second optical lens, and finally is emitted through the optical prism and the fourth optical lens.

2. A large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The multiple optical surfaces are respectively a first optical surface, a second optical surface, a third optical surface and a fourth optical surface, wherein an included angle a between the first optical surface and the fourth optical surface satisfies: 80°≤a≤100°; an included angle b between the first optical surface and the second optical surface satisfies: 100°≤b≤120°; and an included angle c between the third optical surface and the fourth optical surface satisfies: 100°≤c≤120°.

3. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The effective focal length of the second optical lens and the effective focal length of the eyepiece lens satisfy: 1.1≤f2 / f≤1.5, where f2 is the effective focal length of the second optical lens, and f is the effective focal length of the eyepiece lens.

4. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The effective focal length of the third optical lens and the effective focal length of the eyepiece lens satisfy: 2.5 ≤ f3 / f ≤3, where f3 is the effective focal length of the third optical lens, and f is the effective focal length of the eyepiece lens.

5. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The effective focal length of the first optical lens satisfies: |f1|≥100; the effective focal length of the fourth optical lens satisfies: |f4|≥100.

6. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The surface shape of the first surface of the first optical lens and the second surface of the fourth optical lens is any one of an even-order aspheric surface, a polynomial, an extended polynomial or a Zernike standard vector high.

7. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The surface shapes of the second surface of the second optical lens and the second surface of the third optical lens include either a standard surface or an even-order aspherical surface.

8. The large-field-of-view compact eyepiece lens for near-eye display according to claim 1, characterized in that: The surfaces of the first optical lens, the second optical lens, the third optical lens and the fourth optical lens that are in contact with the optical prism are all planes.

9. A near-eye display device, characterized in that: It comprises an image source, an eyepiece lens and a waveguide, wherein the eyepiece lens is a large-field-of-view compact eyepiece lens for near-eye display according to any one of claims 1 to 8, and the image source is used to output image light; the eyepiece lens is arranged on a side where the image source outputs image light, and is used to change the optical path of the image light; the waveguide is arranged at the light emitting end of the eyepiece lens, and is used to transmit the light emitted by the eyepiece lens.

10. The near-eye display device according to claim 9, characterized in that: The image source includes any one of a silicon-based liquid crystal display, an organic light emitting diode, and a micro light emitting diode; and the waveguide sheet is at least one of a geometric light waveguide or a diffraction light waveguide.

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