Precise augmented reality optical module structure and assembling method

Abstract

The invention discloses a precise augmented reality optical module structure and an assembling method, the optical module structure comprises an optical module shell, a display screen, an optical lens group and a waveguide lens group are sequentially arranged on the optical module shell along a light path direction, and the waveguide lens group comprises a near-glasses lens, a waveguide and a visual correction lens. A reflecting surface is arranged at one end, close to an optical path of the optical lens group, of the waveguide, and virtual image information transmitted by the optical path is reflected into the waveguide and transmitted to a semi-reflecting transmission surface of the waveguide; according to the optical module, the structure is optimized from an optical part, so that the optical module is compact in structure, the size is reduced, and the optical module can be well compatible with development of subsequent terminal products; the problems of size miniaturization and large field angle compatibility of the augmented reality optical module structural member are solved, and the high-precision requirement of the optical module structure is met.

Description

Technical Field

[0001] The present invention relates to the technical field of VR equipment, and in particular to a precision augmented reality optical module structure and an assembly method. Background Art

[0002] Augmented reality optical modules are small in size, can integrate image information from the real world, and are becoming more and more like everyday glasses in appearance. They are the main technical trend and optical module product form of the future virtual reality industry.

[0003] The enhanced optical modules on the market today need to solve the compatibility issues of small size and large field of view, as well as the existing one-dimensional pupil expansion optical modules with poor imaging quality, low brightness, and the inability to achieve both the simplicity of the optical module structure and the quality of the virtual image. At the same time, the virtual image is also affected by the product precision, and the overall image quality is relatively poor, with defects such as optical distortion, field curvature, stray light and ghosting, which seriously affects the user experience of the final product. Summary of the invention

[0004] Technical purpose: In view of the shortcomings of the above-mentioned existing augmented reality optical modules, the present invention discloses a precision augmented reality optical module structure and assembly method.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A precision augmented reality optical module structure comprises an optical module shell, on which a display screen, an optical lens group and a waveguide lens group are sequentially arranged along the optical path direction, the waveguide lens group comprises a near-eye lens, a waveguide and a vision correction lens, a reflective surface is arranged at one end of the waveguide close to the optical path of the optical lens group, and virtual image information transmitted by the optical path is reflected into the waveguide and transmitted to the semi-reflective transmission surface of the waveguide; the near-eye lens is arranged in the area where the semi-reflective transmission surface of the waveguide is located, and is located on the side close to the human eye, and the vision correction lens is arranged on the other side opposite to the near-eye lens, and the near-eye lens, the waveguide and the vision correction lens together form a transmission structure with uniform thickness, so that external image information enters the human eye after transmission.

[0006] Preferably, the near-eye lens of the present invention adopts a spherical high-refractive-index plano-convex resin lens, including a spherical convex lens and a spacer glued to each other, and the spacer is attached to the surface of the waveguide to fix the near-eye lens.

[0007] Preferably, the vision correction lens of the present invention is an aspheric plano-concave resin lens with a small cone coefficient, comprising an aspheric concave lens and a second spacer that are glued and fixed to each other, and the second spacer is attached to the surface of the corresponding waveguide.

[0008] Preferably, the optical lens group of the present invention includes a doublet lens and a multi-order aspheric convex lens and a multi-order aspheric meniscus lens arranged on both sides of the doublet lens; the doublet lens, the multi-order aspheric convex lens and the multi-order aspheric meniscus lens are all symmetrically cut and formed along a vertical plane where the optical axis of the optical lens group is located as a symmetry plane, forming a concentric structure with the optical axis of the optical lens group as the center.

[0009] Preferably, a plurality of mounting holes for mounting the optical lens group are correspondingly provided in the housing of the optical module of the present invention, the mounting holes match the corresponding lens sizes, and a step surface for axially limiting the corresponding lens is formed at the interface between adjacent mounting holes.

[0010] Preferably, the mounting hole of the present invention is provided with process fillets at positions corresponding to the four corners of the lens, and the installed lens is fixed by glue through the process fillets.

[0011] Preferably, a waveguide cover is provided at the rear end of the optical module housing of the present invention, and the waveguide cover is detachably connected to the optical module housing via a snap-on structure, and the waveguide cover is used to fix the waveguide while blocking light from the side of the waveguide away from the optical lens group from entering the waveguide.

[0012] Preferably, the waveguide cover plate and the optical module housing of the present invention are both formed by processing using 7 series aluminum alloy.

[0013] The present invention discloses an assembly method based on the above-mentioned precision augmented reality optical module structure, firstly, an eccentricity detector is used to detect and locate the installation position of each lens of the optical lens group in the optical module housing, and then glue is applied to fix the lens; Then the display screen and waveguide mirror group are debugged and positioned, the display screen is used to project the image, and a camera is used at the image output end of the waveguide mirror group to obtain the displayed image. The position of the waveguide mirror group is adjusted so that the output image meets the requirements, and then glue is applied to fix it to complete the assembly of the optical module structure.

[0014] Beneficial effects: The precision augmented reality optical module structure and assembly method disclosed in the present invention have the following beneficial effects: 1. The lenses of the optical lens group of the present invention are formed by symmetrical trimming with the vertical plane where the optical axis of the optical lens group is located as the symmetry center, which can reduce the X-direction size of the optical lens group and the overall volume of the optical module. The lenses are concentrically distributed and can be integrated and installed in the mounting holes of the optical module housing, thereby reducing the difficulty of positioning during assembly and ensuring positioning accuracy.

[0015] 2. The waveguide lens assembly of the present invention is provided with a near-eye lens, which generates optical focal length at the front end of the waveguide to compress the field angle of the light path at the front end of the one-dimensional waveguide, thereby compressing the light aperture of the waveguide optical machine section and extending the paraxial optical path, which can well increase the eye entrance distance and the distance that light propagates in the waveguide, that is, increase the DO value; it can also compress the size height of the optical module structure and further reduce the volume.

[0016] 3. The waveguide lens assembly of the present invention forms an optical system similar to flat glass through the near-eye lens, waveguide and vision correction lens. While projecting virtual images, it will not affect the observation of real information. The aspherical design of the vision correction lens can further compensate for the aberration and optical focal length caused by the spherical convex lens of the near-eye lens.

[0017] 4. The optical module shell of the present invention uses mounting holes produced by machining to install and position each lens of the optical lens group. It can be processed and formed in one step, and process fillets are set around the mounting holes to fix the lenses by gluing. This can optimize the installation space of the shell, achieve lens fixation, and ensure the installation and positioning accuracy of the lenses, thereby meeting the optical eccentricity accuracy requirements.

[0018] 5. The optical module housing and waveguide cover of the present invention are both made of 7 series aluminum alloy. The thermal strain coefficient can meet the dimensional tolerance requirements of the optical module. Within the operating temperature range, the lens offset caused by temperature is reduced to ensure the normal operation of the optical module. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 This is an exploded view of the optical module structure of the present invention; Figure 2 It is a schematic diagram of the structure of the optical lens assembly of the present invention; Figure 3 It is a schematic diagram of assembling the optical lens assembly and the optical module housing of the present invention; Figure 4 This is a structural diagram of the optical module housing of the present invention; Figure 5 It is a schematic diagram of the structure of the waveguide mirror assembly of the present invention; Figure 6 A schematic diagram of image projection by the waveguide mirror assembly of the present invention; Figure 7 It is a thermal expansion line diagram of the optical module housing of the present invention; Figure 8 This is a schematic diagram of the optical path of the waveguide of the present invention without adding a near-eye lens; Fig. 9A schematic diagram of the optical path after adding a near-eye lens to the waveguide of the present invention; Fig.10 A display projection grid diagram when assembling the optical module of the present invention; Fig.11 A grid image captured by a camera when assembling the optical module of the present invention; Among them, 1-optical module housing, 2-display screen, 3-optical lens group, 4-waveguide lens group, 5-near-eye lens, 6-waveguide, 7-vision correction lens, 8-reflective surface, 9-semi-reflective transmission surface, 10-spherical convex lens, 11-spacer, 12-aspherical concave lens, 13-second spacer, 14-double-cemented lens, 15-multi-order aspheric convex lens, 16-multi-order aspheric meniscus lens, 17-mounting hole, 18-process fillet, 19-waveguide cover. DETAILED DESCRIPTION

[0021] Reference will now be made in detail to embodiments of the present disclosure, one or more examples of which are set forth herein below. Each embodiment and example is provided by way of explanation of the apparatus, composition and materials of the present disclosure, rather than limitation. On the contrary, the following description provides a convenient illustration of an exemplary embodiment for implementing the present disclosure. In fact, it will be clear to those skilled in the art that various modifications and variations may be made in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0022] like Figure 1-Figure 6 The figure shows a precision augmented reality optical module structure disclosed in the present invention, comprising an optical module housing 1, on which a display screen 2, an optical lens group 3 and a waveguide lens group 4 are sequentially arranged along the optical path direction, wherein the waveguide lens group 4 comprises a near-eye lens 5, a waveguide 6 and a vision correction lens 7, wherein a reflective surface 8 is arranged at one end of the waveguide 6 close to the optical path of the optical lens group 3, and the virtual image information transmitted by the optical path is reflected into the waveguide 6 and transmitted to the semi-reflective transmission surface 9 of the waveguide 6; the near-eye lens 5 is arranged at the semi-reflective transmission surface 9 of the waveguide 6 In the area, located on the side close to the human eye, the vision correction lens 7 is arranged on the other side opposite to the near eye lens 5, and the near eye lens 5, the waveguide 6 and the vision correction lens 7 together form a transmission structure with uniform thickness, so that the external image information enters the human eye after transmission; a waveguide cover plate 19 is arranged at the rear end of the optical module housing 1 of the present invention, and the waveguide cover plate 19 is detachably connected to the optical module housing 1 through a snap-on structure. The waveguide cover plate 19 is used to fix the waveguide 6 while blocking the light from the side of the waveguide 6 away from the optical lens group from entering the waveguide 6.

[0023] The waveguide cover plate 19 and the optical module housing 1 are both made of 7 series aluminum alloy. The thermal strain coefficient of 7 series aluminum alloy is 23.6x10 / K, which meets the dimensional tolerance requirements of the product. Figure 7As shown, the profile size of the 7 series aluminum alloy at room temperature 25°C is taken as the reference zero point. In order to facilitate data comparison, the present invention Figure 7 It is represented by a horizontal straight line with a vertical coordinate of 0; Figure 7 The broken line in the figure indicates the thermal deformation of the 7 series aluminum alloy relative to its dimensions at room temperature at the corresponding temperature within the range of -10℃-60℃. It can be seen that the overall thermal expansion of the optical module housing made of 7 series aluminum alloy is within ±0.02mm, which can ensure the installation accuracy of each assembly component of the optical module within the operating temperature range.

[0024] The near-eye lens 5 of the present invention adopts a spherical high-refractive-index plano-convex resin lens with a refractive index of 1.6-1.9, including a spherical convex lens 10 and a spacer 11 glued to each other, and the spacer 11 is bonded to the surface of the waveguide 6 to fix the near-eye lens 5; the vision correction lens 7 is an aspheric plano-concave resin lens with a small cone coefficient, and the cone coefficient is 1-10; it includes an aspheric concave lens 12 and a second spacer 13 glued to each other, and the second spacer 13 is bonded to the surface of the corresponding waveguide 6. The waveguide 6 is a one-dimensional array pupil expansion waveguide, which is composed of 6 pieces of semi-reflective and transmissive coated surfaces with different ratios glued together.

[0025] A transmission structure similar to flat glass is formed by the near-eye lens 5, the waveguide 6 and the vision correction lens 7. The optical virtual image information is reflected by the reflection surface 8 in the waveguide and can be fully reflected inside the waveguide to propagate to the semi-reflection transmission surface 9 and then deflected to the direction of the human eye; the optical propagation of the virtual information is isolated inside the waveguide and the cleanliness of the waveguide surface can be ensured; the external natural light can also enter the human eye through the vision correction lens, the waveguide and the vision correction near-eye lens, and merge with the virtual image information. The vision correction lens 7 corrects the refractive power of the near-eye lens on the real image information to compensate for the aberration and optical focal length caused by the convex lens of the near-eye lens 5, thereby realizing the perfect fusion of virtual image information and real image information.

[0026] In addition, the near-eye lens 5 provided in the present invention utilizes a spherical lens structure to generate optical power at the front end of the waveguide 6, which can compress the field angle of the optical path at the front end of the waveguide 6, thereby compressing the aperture of the waveguide optical machine section, and extending the paraxial optical path on the basis of the original structure. Figure 8 and Fig. 9 As shown, when the near-eye lens 5 is not added, , and after adding near-eye lens 5, ; Where Dy: optical machine height, : Pupil size, : eye-to-eye distance, Ly: paraxial optical path length, L: waveguide DO value, n: refractive index of waveguide material; : Field of view, : Optical power of myopia lens lens; since the paraxial optical path from the human eye to the optical machine is composed of the eye-entry distance of the optical machine and the propagation distance of the waveguide, the present invention can well increase the eye-entry distance and the distance of light propagation in the waveguide, that is, increase the DO value, and can also reduce the optical machine height Dy, thereby compressing the size height of the optical module and achieving compatibility between a large field of view and a small size.

[0027] In a specific embodiment, the optical lens group 3 of the present invention includes a double cemented lens 14 and a multi-order aspheric convex lens 15 and a multi-order aspheric meniscus lens 16 arranged on both sides of the double cemented lens 14, wherein the multi-order aspheric convex lens 15 is located on the side where the display screen 2 is located; the double cemented lens 14, the multi-order aspheric convex lens 15 and the multi-order aspheric meniscus lens 16 are all symmetrically trimmed along the vertical plane where the optical axis is located as the symmetry plane to form a concentric structure centered on the optical axis of the optical lens group 3. The symmetrical trimming process can reduce the lens size in the X direction, thereby reducing the overall size of the optical module. At the same time, a plurality of lenses are formed into a concentric structure centered on the optical axis of the optical lens group, and a plurality of corresponding optical lens components are opened in the optical module housing 1. The mounting hole 17 installed in group 3 matches the corresponding lens size, and a step surface for axially limiting the corresponding lens is formed at the interface of adjacent mounting holes 17. The lens and the optical module housing 1 can be assembled in sequence according to the direction of the light path, and positioned one by one to improve the overall assembly positioning accuracy; the mounting hole 17 has a process fillet 18 at the position corresponding to the four corners of the lens, and the installed lens is fixed by gluing through the process fillet 18. The setting of the process fillet 18 meets the production and processing requirements of high-precision milling machines and can be used for later gluing and fixing of the lens, thereby optimizing the structural space of the optical module housing 1. Screw mounting holes or pin holes can also be preset on the outside of the optical module housing 1 to facilitate the subsequent integration of the optical module into the VR product.

[0028] The present invention discloses an assembly method based on the above-mentioned precision augmented reality optical module structure, firstly, an eccentricity detector is used to detect and locate the installation position of each lens of the optical lens group in the optical module housing, and then glue is applied to fix the lens; Use the concentric detection tool on the eccentricity detector to position and fix the optical module housing 1. Install them one by one in the order of the optical path. The detection tool detects the eccentricity and axial distance of the lens to ensure that the off-axis value of the lens is ≤0.02mm and the tilt is ≤1′. After meeting the requirements, apply silicone rubber and fill glue at the process fillet 18 to fix it.

[0029] Then, the display screen and the waveguide lens assembly are debugged and positioned on the optical and mechanical assembly platform, and the image is projected using the display screen. In the embodiment of the present invention, the image is projected as follows: Fig.10 The grid image is assembled and tested, and a camera is used at the image output end of the waveguide mirror assembly to obtain the displayed image, and the image is obtained as follows Fig.11 As shown in the captured image, the position of the waveguide mirror group is adjusted to make the output image meet the requirements, and then glue is applied to fix it to complete the assembly of the optical module structure. The movement of the waveguide mirror group can be achieved through a six-axis mobile platform, and the waveguide mirror group is fixed by setting a waveguide fixing tool on the mobile end of the six-axis mobile platform.

[0030] The present invention optimizes the structure starting from the optical parts, so that the optical module has a compact structure and reduced size, which can be well compatible with the development of subsequent terminal products. The optical imaging solution of the optical module is adjusted by a near-eye lens, which realizes the miniaturization of the size of the augmented reality optical module structural parts and compatibility with a large field of view and meets the high-precision requirements of the optical-mechanical structure. It has high processing feasibility, a simple and compact structure, is easy to assemble and debug, and meets optical standards, provides user-end comfort, and can ensure a high yield rate of production and largely eliminate the optical leakage problem caused by surface contamination of the optical module.

Claims

1. A precision augmented reality optical module structure, characterized in that: The invention comprises an optical module housing (1), on which a display screen (2), an optical lens group (3) and a waveguide lens group (4) are arranged in sequence along the optical path direction. The waveguide lens group (4) comprises a near-eye lens (5), a waveguide (6) and a vision correction lens (7). A reflection surface (8) is arranged at one end of the waveguide (6) close to the optical path of the optical lens group (3), and virtual image information transmitted by the optical path is reflected into the waveguide (6) and transmitted to the semi-reflective transmission surface (9) of the waveguide (6); the near-eye lens (5) is arranged in the area where the semi-reflective transmission surface (9) of the waveguide (6) is located, and is located on the side close to the human eye; the vision correction lens (7) is arranged on the other side opposite to the near-eye lens (5); the near-eye lens (5), the waveguide (6) and the vision correction lens (7) together form a transmission structure with uniform thickness, so that external image information enters the human eye after being transmitted.

2. The precision augmented reality optical module structure according to claim 1, characterized in that: The near-eye lens (5) adopts a spherical high-refractive-index plano-convex resin lens, comprising a spherical convex lens (10) and a spacer (11) that are glued to each other, and the spacer (11) is attached to the surface of the waveguide (6) to fix the near-eye lens (5).

3. The precision augmented reality optical module structure according to claim 2, characterized in that: The vision correction lens (7) is an aspheric plano-concave resin lens with a small cone coefficient, comprising an aspheric concave lens (12) and a second spacer (13) that are glued and fixed to each other, and the second spacer (13) is attached to the surface of the corresponding waveguide (6).

4. The precision augmented reality optical module structure according to claim 1, characterized in that: The optical lens group (3) comprises a double cemented lens (14) and a multi-order aspheric convex lens (15) and a multi-order aspheric meniscus lens (16) arranged on both sides of the double cemented lens (14); the double cemented lens (14), the multi-order aspheric convex lens (15) and the multi-order aspheric meniscus lens (16) are all formed by symmetrical cutting along a vertical plane where the optical axis of the optical lens group (3) is located as a symmetry plane, so as to form a concentric structure centered on the optical axis of the optical lens group (3).

5. The precision augmented reality optical module structure according to claim 4, characterized in that: A plurality of mounting holes (17) for mounting the optical lens group (3) are correspondingly provided in the optical module housing (1); the mounting holes (17) match the size of the corresponding lenses; and a step surface for axially limiting the corresponding lenses is formed at the interface between adjacent mounting holes (17).

6. The precision augmented reality optical module structure according to claim 5, characterized in that: The mounting hole (17) is provided with process fillets (18) at positions corresponding to the four corners of the lens, and the installed lens is fixed by glue through the process fillets (18).

7. The precision augmented reality optical module structure according to claim 5, characterized in that: A waveguide cover plate (19) is disposed at the rear end of the optical module housing (1); the waveguide cover plate (19) and the optical module housing (1) are detachably connected via a snap-fit ​​structure; the waveguide cover plate (19) is used to fix the waveguide (6) while blocking light from the side of the waveguide (6) away from the optical lens group (3) to enter the waveguide (6).

8. The precision augmented reality optical module structure according to claim 7, characterized in that: The waveguide cover plate (19) and the optical module housing (1) are both formed by processing using 7 series aluminum alloy.

9. The method for assembling a precision augmented reality optical module structure according to any one of claims 1 to 8, characterized in that: First, the installation position of each lens of the optical lens group in the optical module housing is detected and located by an eccentricity detector, and then fixed by glue; Then the display screen and waveguide mirror group are debugged and positioned, the display screen is used to project the image, and a camera is used at the image output end of the waveguide mirror group to obtain the displayed image. The position of the waveguide mirror group is adjusted so that the output image meets the requirements, and then glue is applied to fix it to complete the assembly of the optical module structure.

Images