Micro projection lens
By using a micro-projection lens composed of glass aspherical lens and plastic aspherical lens in AR glasses, the problem of thermal out-of-focus of AR glasses is solved, and stable imaging is achieved when temperature changes is achieved, improving user experience and the lightness of the device sex.
Patent Information
- Application Number
- CN202420686454.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-03
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-04-03
AI Technical Summary
Due to the small and compact structure of the micro-projection lens of AR glasses, it is impossible to perform secondary focus. The increase in temperature during operation of the Micro LED display chip causes the lens to lose focus, the resolution decreases, and the imaging is blurred, which affects the user experience.
Using a micro-projection lens composed of glass aspherical lens and plastic aspherical lens, the reasonable combination of five lenses reduces the impact of temperature on the lens, and self-compensate the focus range through the plastic lens to ensure that the lens basically changes in ambient temperature. No heat loss.
It effectively improves the imaging quality and stability of the lens, reduces thermal out-of-focus phenomenon, enhances user experience, and makes the AR glasses display solution thinner.
Smart Images
Figure CN222145313U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of micro-projection optics, in particular to a projection lens. Background Art
[0002] With the development of near-eye display technology, more and more AR / VR display devices have been launched. The more mature solution is waveguide plus micro-projection optical machine. The micro-projection optical machine based on Micro LED is considered to be the trend of AR display solution due to its smaller pixel size and higher brightness.
[0003] At present, the traditional projection lens will automatically lose focus after being used for a period of time, that is, although the focal length is adjusted at the beginning, the lens needs to be refocused after a period of use. Some have added an automatic focus function to solve the lens defocus problem, by moving the movable lens, finding the movable lens position corresponding to the highest clarity value within the moving range, and controlling the movable lens to fall at the position with the highest clarity value within the moving range to achieve refocusing; some have refocused through the overall or local structure.
[0004] However, for AR glasses, the optical machine and glasses structure need to be very small and compact, and there is no possibility of secondary focusing. The Micro LED display chip has a high temperature when working. The sharp increase in temperature causes the projection lens structure to expand and contract, and the lens becomes thermally defocused, resulting in a decrease in lens resolution and blurred imaging, which greatly affects the user experience. Utility Model Content
[0005] The main purpose of the utility model is to propose a micro-projection lens, which aims to solve the problem that existing AR glasses require very small and compact optical machine and glasses structure, and there is no possibility of secondary focusing. The Micro LED display chip has a high temperature when working. The sharp increase in temperature causes the lens of the projection lens structure to expand and contract, and the lens becomes thermally defocused, resulting in a decrease in lens resolution and blurred imaging, which greatly affects the user experience.
[0006] To achieve the above object, the utility model provides a micro-projection lens, the micro-projection lens having an object side and an image side correspondingly arranged along the optical axis direction, the micro-projection lens comprising a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object side to the image side, and the focal length of the micro-projection lens is f, 5.9 mm <f<6.1mm;
[0007] The first lens is a glass aspheric lens, and the second lens, the third lens, the fourth lens and the fifth lens are all plastic aspheric lenses.
[0008] Optionally, the first lens is a positive lens, and the object side surface of the first lens is a convex surface, and the image side surface is a concave surface;
[0009] The second lens is a positive lens, and the object side surface of the second lens is convex, and the image side surface is concave;
[0010] The third lens is a negative lens, and the object side surface and the image side surface of the third lens are concave;
[0011] The fourth lens is a positive lens, and the object side surface of the fourth lens is a concave surface, and the image side surface is a convex surface;
[0012] The fifth lens is a positive lens, and the object side surface of the fifth lens is a concave surface, and the image side surface is a convex surface.
[0013] Optionally, the semi-aperture of the first lens is d1, 1.6 mm <d1<1.8mm;
[0014] The semi-aperture of the second lens is d2, 1.3 mm <d2<1.6mm;
[0015] The semi-aperture of the third lens is d3, 1 mm <d3<1.3mm;
[0016] The semi-aperture of the fourth lens is d4, 1.1 mm <d4<1.4mm;
[0017] The semi-aperture of the fifth lens is d5, 1.6 mm <d5<1.9mm。
[0018] Optionally, the core thickness of the first lens is L1, 0.8 mm <L1<0.95mm;
[0019] The core thickness of the second lens is L2, 0.95 mm <L2<1.1mm;
[0020] The core thickness of the third lens is L3, 0.3 mm <L3<0.4mm;
[0021] The core thickness of the fourth lens is L4, 0.35 mm <L4<0.45mm;
[0022] The core thickness of the fifth lens is L5, 0.7 mm <L5<0.8mm。
[0023] Optionally, the refractive index of the first lens is n1,1.7 <n1<1.9;
[0024] The refractive index of the second lens is n2,1.49 <n2<1.6;
[0025] The refractive index of the third lens is n3,1.6 <n3<1.7;
[0026] The refractive index of the fourth lens is n4,1.6 <n4<1.7;
[0027] The refractive index of the fifth lens is n5, 1.55 <n5<1.65。
[0028] Optionally, the change amount of the micro-projection lens is △ft, the change amount of the back focus of the second lens is △f2, the change amount of the back focus of the third lens is △f3, the change amount of the back focus of the fourth lens is △f4, the change amount of the back focus of the fifth lens is △f5, and the micro-projection lens meets the following conditions:
[0029] △ft=△f2+△f3+△f4+△f5<5um.
[0030] Optionally, the micro-projection lens further includes an aperture stop, and the aperture stop is arranged on a side of the first lens facing away from the second lens.
[0031] Optionally, the distance from the aperture to the image side is the total optical length TTL of the micro-projection lens, and TTL<5.6 mm.
[0032] Optionally, the radius of the aperture is d0, 1 mm <d0<2.5mm。
[0033] Optionally, the distance from the aperture to the first lens is L0, and L0<1 mm.
[0034] In the technical solution provided by the utility model, five lenses are used to form the micro-projection lens, wherein the first lens is a glass aspheric lens, and the second lens, the third lens, the fourth lens and the fifth lens are all plastic aspheric lenses. The aspheric lens has a better curvature radius characteristic and has the advantages of improving distortion aberration and improving astigmatism aberration. After the aspheric lens is used, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. At the same time, the glass aspheric lens can make the first lens unaffected by temperature, or the temperature effect is very small. The plastic aspheric lens can also self-compensate the focal range of the micro-projection lens through the plastic lens, so that the micro-projection lens is basically free from thermal defocus when the ambient temperature changes and the imaging quality of the lens is maintained at a high level. The problem of thermal defocus is greatly improved, providing high stability for the micro-projection lens and enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0036] Figure 1 A three-dimensional schematic diagram of an embodiment of a micro-projection lens provided by the utility model;
[0037] Figure 2 for Figure 1 Schematic diagram of the optical path of the micro-projection lens;
[0038] Figure 3 for Figure 1 A schematic diagram of imaging MTF of an embodiment of a micro-projection lens at 20°C;
[0039] Figure 4 for Figure 1 A schematic diagram of defocusing of an embodiment of a micro-projection lens at 20° C.
[0040] Figure 5 for Figure 1 A schematic diagram of imaging MTF of an embodiment of a micro-projection lens at 60°C;
[0041] Figure 6 for Figure 1 A schematic diagram of defocusing of an embodiment of a micro-projection lens at 60° C.
[0042] Figure 7 for Figure 1 A schematic diagram of a field area of a micro-projection lens according to an embodiment of the present invention;
[0043] Figure 8 for Figure 1 Schematic diagram of distortion performance of an embodiment of a micro-projection lens in FIG.
[0044] Description of Figure Numbers:
[0045] Label name Label name 100 Micro Projection Lens 3 The third lens 1 First lens 4 The fourth lens 2 Second lens 5 Fifth lens
[0046] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0047] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0048] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0049] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the utility model.
[0050] At present, the commonly used projection mirror will automatically lose focus after being used for a period of time, that is, although the focal length is adjusted at the beginning, the lens must be refocused after a period of use. Some have added an automatic focus function to solve the lens defocus problem, by moving the movable lens, finding the movable lens position corresponding to the highest clarity value within the moving range, and controlling the movable lens to fall to the position with the highest clarity value within the moving range to achieve refocusing; some have refocused through the overall or local structure.
[0051] However, for AR glasses, the optical machine and glasses structure need to be very small and compact, and there is no possibility of secondary focusing. The Micro LED display chip has a high temperature when working. The sharp increase in temperature causes the projection lens structure to expand and contract, and the lens becomes thermally defocused, resulting in a decrease in lens resolution and blurred imaging, which greatly affects the user experience and poses a high problem.
[0052] In order to solve the above problems, the present invention provides a micro-projection lens 100. Figures 1 to 3A specific embodiment of the micro-projection lens provided by the present utility model.
[0053] Please refer to Figures 1 to 3 , the micro-projection lens 100 has an object side and an image side arranged correspondingly along the optical axis direction. The micro-projection lens 100 includes a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, and a fifth lens 11 arranged in sequence from the object side to the image side. The focal length of the micro-projection lens 100 is f, where 5.9 mm < f < 6.1 mm. The first lens 1 is a glass aspherical lens, and the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 11 are all plastic aspherical lenses.
[0054] In the technical solution provided by the present utility model, five lenses are used to form the micro-projection lens 100. Among them, the first lens 1 is a glass aspherical lens, and the second lens 2, the third lens 3, the fourth lens 4, and the fifth lens 11 are all plastic aspherical lenses. Aspherical lenses have better curvature radius characteristics and have the advantages of improving distortion aberration and astigmatism aberration. After using aspherical lenses, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality of the lens. At the same time, by using a glass aspherical lens, the first lens 1 can be unaffected by temperature, or is hardly affected by temperature. And by using plastic aspherical lenses, the optical power range of the micro-projection lens 100 can be self-compensated by the plastic lenses. Thus, when the ambient temperature changes, the micro-projection lens 100 has basically no thermal defocus and the imaging quality of the lens remains at a high level, and the problem of thermal defocus is greatly improved, providing high stability for the micro-projection lens 100 and enhancing the user experience.
[0055] It can be understood that in the present utility model, the focal length of the micro-projection lens 100 is f, where 5.9 mm < f < 6.1 mm. With such a setting, the size of the micro-projection lens 100 can be made smaller. By greatly reducing the size of the micro-projection lens 100, the display solution of the AR glasses can be made thinner and lighter, reducing the difficulty of the glasses structure design.
[0056] It should be noted that in an embodiment of the present utility model, the focal length f of the micro-projection lens 100 can be set to 5.91, 5.92, 5.93, 5.94, 5.95, 5.96, 5.97, 5.98, 5.99, 6.0, 6.01, 6.02, 6.03, 6.04, 6.05, 6.06, 6.07, 6.08, 6.09, 6.10, etc., or set to other data, and the present utility model does not limit this.
[0057] Further, in the present utility model, the first lens 1 is a positive lens, and the object side surface of the first lens 1 is convex, and the image side surface is concave. The second lens 2 is a positive lens, and the object side surface of the second lens 2 is convex, and the image side surface is concave. The third lens 3 is a negative lens, and the object side surface of the third lens 3 is concave, and the image side surface is concave. The fourth lens 4 is a positive lens, and the object side surface of the fourth lens 4 is concave, and the image side surface is convex. The fifth lens 11 is a positive lens, and the object side surface of the fifth lens 11 is concave, and the image side surface is convex. With such a setting, through a reasonable combination structure among the five lenses, the micro projection lens 100 can still work stably and there is almost no thermal defocus when the ambient temperature changes drastically.
[0058] Furthermore, in an embodiment of the present utility model, the semi-aperture of the first lens 1 is d1, and 1.6 mm < d1 < 1.8 mm; the semi-aperture of the second lens 2 is d2, and 1.3 mm < d2 < 1.6 mm; the semi-aperture of the third lens 3 is d3, and 1 mm < d3 < 1.3 mm; the semi-aperture of the fourth lens 4 is d4, and 1.1 mm < d4 < 1.4 mm; the semi-aperture of the fifth lens 11 is d5, and 1.6 mm < d5 < 1.9 mm.
[0059] It should be noted that the present utility model does not limit the specific values of the semi-aperture of the first lens 1, the semi-aperture of the second lens 2, the semi-aperture of the third lens 3, the semi-aperture of the fourth lens 4, and the semi-aperture of the fifth lens 11.
[0060] For example, in one embodiment of the present invention, the semi-aperture d1 of the first lens 1 can be set to 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.70, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, etc.; the semi-aperture d2 of the second lens 2 can be set to 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, etc. 0, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59, etc.; the semi-aperture d3 of the third lens 3 can be set to 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1 .17, 1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, etc.; the semi-aperture d4 of the fourth lens 4 can be set to 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, 1.30, 1.31, 1.32, 1.33 , 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, etc.; the semi-aperture d5 of the fifth lens 11 can be set to 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 170, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, 180, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, etc.
[0061] In other embodiments of the present invention, the semi-aperture of the first lens 1, the semi-aperture of the second lens 2, the semi-aperture of the third lens 3, the semi-aperture of the fourth lens 4 and the semi-aperture of the fifth lens 11 can also be set to other values, and the present invention is not limited thereto.
[0062] In addition, in the present utility model, the core thickness of the first lens 1 is L1, where 0.8 mm < L1 < 0.95 mm; the core thickness of the second lens 2 is L2, where 0.95 mm < L2 < 1.1 mm; the core thickness of the third lens 3 is L3, where 0.3 mm < L3 < 0.4 mm; the core thickness of the fourth lens 4 is L4, where 0.35 mm < L4 < 0.45 mm; and the core thickness of the fifth lens 11 is L5, where 0.7 mm < L5 < 0.8 mm.
[0063] Similarly, the present utility model does not limit the specific values of the core thickness of the first lens 1, the core thickness of the second lens 2, the core thickness of the third lens 3, the core thickness of the fourth lens 4, and the core thickness of the fifth lens 11.
[0064] For example, in an embodiment of the present utility model, the core thickness L1 of the first lens 1 can be set to, for example, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, etc.; the core thickness L2 of the second lens 2 can be set to, for example, 0.96, 0.97, 0.98, 0.99, 1.00, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, etc.; the core thickness of the third lens 3 can be set to, for example, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39; the core thickness L4 of the fourth lens 4 can be set to, for example, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44, etc.; and the core thickness L5 of the fifth lens 11 can be set to, for example, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, etc.
[0065] Of course, in other embodiments of the present utility model, the core thickness of the first lens 1, the core thickness of the second lens 2, the core thickness of the third lens 3, the core thickness of the fourth lens 4, and the core thickness of the fifth lens 11 can also be set to other values, and the present utility model does not limit this.
[0066] Specifically, in the present utility model, the refractive index of the first lens 1 is n1, where 1.7 < n1 < 1.9; the refractive index of the second lens 2 is n2, where 1.49 < n2 < 1.6; the refractive index of the third lens 3 is n3, where 1.6 < n3 < 1.7; the refractive index of the fourth lens 4 is n4, where 1.6 < n4 < 1.7; and the refractive index of the fifth lens 11 is n5, where 1.55 < n5 < 1.65.
[0067] The present invention also does not limit the refractive index of the first lens 1 , the refractive index of the second lens 2 , the refractive index of the third lens 3 , the refractive index of the fourth lens 4 , and the refractive index of the fifth lens 11 .
[0068] It can be understood that, in an embodiment of the present invention, the refractive index n1 of the first lens 1 can be set to 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, 1.80, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, etc.; the refractive index n2 of the second lens 2 can be set to 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1 .59, etc.; the refractive index n3 of the third lens 3 can be set to 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, etc.; the refractive index n4 of the fourth lens 4 can be set to 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, etc.; the refractive index n5 of the fifth lens 11 can be set to 1.56, 1.57, 1.58, 1.59, 1.60, 1.61, 1.62, 1.63, 1.64, etc.
[0069] Of course, in other embodiments of the present invention, the refractive index of the first lens 1, the refractive index of the second lens 2, the refractive index of the third lens 3, the refractive index of the fourth lens 4 and the refractive index of the fifth lens 11 can also be set to other values, and the present invention does not limit this.
[0070] Furthermore, in order to ensure that the multiple plastic lenses of the micro-projection lens 100 can compensate for the thermal defocusing effects caused by thermal deformation during the change of the ambient temperature, so that the overall imaging quality of the micro-projection lens 100 is not affected. In an embodiment of the present utility model, the change amount of the micro-projection lens 100 is △ft, the back focus change amount of the second lens 2 is △f2, the back focus change amount of the third lens 3 is △f3, the back focus change amount of the fourth lens 4 is △f4, and the back focus change amount of the fifth lens 11 is △f5, and the micro-projection lens 100 satisfies the following conditions: △ft=△f2+△f3+△f4+△f5<5um.
[0071] It should be noted that, in the present embodiment, the second lens 2, the third lens 3 and the fourth lens 4 are positive lenses. When the ambient temperature increases, the back focus change of the second lens 2, the third lens 3 and the fourth lens 4 is toward the object side of the micro-projection lens 100; the fourth lens 4 is a negative lens. When the ambient temperature increases, the back focus change of the fourth lens 4 is toward the image side of the micro-projection lens 100.
[0072] It is worth mentioning that, in the present invention, the surface shapes of the multiple lenses of the micro-projection lens 100 should satisfy the following formula:
[0073]
[0074] It should be noted that the first expression is the same as the standard surface type, and the second is the sum of the normalized coordinate power series; αi is the aspheric coefficient, expressed in lens units, so the normalized radial coordinate ρ is used.
[0075] In addition, the micro-projection lens 100 further includes an aperture 12, which is disposed on the side of the first lens 1 facing away from the second lens 2. The aperture 12 can adjust the intensity of the light beam irradiated onto the first lens 1 from the object side image.
[0076] Furthermore, the distance from the aperture 12 to the image side is the total optical length TTL of the micro-projection lens 100 , and TTL<5.6 mm.
[0077] Furthermore, in the present invention, the radius of the aperture 12 is d0, 1 mm <d0<2.5mm。
[0078] It can be understood that, in an embodiment of the present invention, the radius d0 of the aperture 12 can be set to 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, etc.
[0079] Of course, in other embodiments of the present invention, the radius of the aperture 12 may also be set to other values, and the present invention does not impose any limitation on this.
[0080] In addition, in the present invention, the distance between the aperture 12 and the first lens 1 is L0, and L0<1 mm.
[0081] Similarly, in an embodiment of the present invention, the distance L0 from the aperture 12 to the first lens 1 can be set to 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.
[0082] In other embodiments of the present invention, the distance from the aperture 12 to the first lens 1 may also be set to other values, which is not limited by the present invention.
[0083] Based on the above content, the micro-projection lens 100 proposed by the present invention can work normally in the range of 20° C.-60° C., while ensuring that the micro-projection lens 100 does not lose focus during operation, and the MTF full frequency is higher than 0.5.
[0084] In a specific embodiment of the present utility model, the object side surface of the aperture 12 is S0, and the image side surface is S1. The first lens 1 is a positive lens, and the object side surface S2 of the first lens 1 is a convex surface, and the image side surface S3 is a concave surface. The second lens 2 is a positive lens, and the object side surface S4 of the second lens 2 is a convex surface, and the image side surface S5 is a concave surface. The third lens 3 is a negative lens, and the object side surface S6 of the third lens 3 is a concave surface, and the image side surface S7 is a concave surface. The fourth lens 4 is a positive lens, and the object side surface S8 of the fourth lens 4 is a concave surface, and the image side surface S9 is a convex surface. The fifth lens 11 is a positive lens, and the object side surface S10 of the fifth lens 11 is a concave surface, and the image side surface S11 is a convex surface. The image side surface of the micro-projection lens 100 is S12.
[0085] It should be noted that, in this embodiment, the basic parameter table of the curvature, material, aperture, and cone coefficient of each lens of the micro-projection lens 100 is shown in Table 1:
[0086] Table 1
[0087]
[0088] Furthermore, in this embodiment, based on this framework, the optimized curvature coefficients of each lens are shown in Table 2:
[0089] Surface number The coefficient of p4 The coefficient of p6 Coefficient of p8 The coefficient of p10 The coefficient of p12 The coefficient of p14 The coefficient of p16 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 1 0.000 0.000 0.000 0.000 0.000 0.000 0.000 2 -6.39E-04 1.37E-04 3.54E-05 3.79E-06 2.03E-06 3.45E-07 7.01E-08 3 -4.33E-04 1.09E-04 2.01E-04 3.36E-05 1.00E-05 1.41E-06 1.09E-06 4 7.84E-03 2.47E-04 7.71E-04 -7.81E-05 -2.17E-05 2.86E-05 1.23E-05 5 1.30E-02 -1.09E-02 1.25E-03 9.12E-04 5.45E-04 1.24E-04 4.69E-05 6 -8.57E-02 3.35E-02 -4.15E-03 8.16E-04 3.42E-04 -2.60E-04 2.93E-04 7 -1.02E-01 4.30E-02 -1.78E-02 -1.47E-03 -6.75E-03 3.58E-02 -3.32E-02 8 -8.11E-02 -1.23E-01 6.48E-02 -1.02E-01 -2.68E-02 1.39E-01 -9.78E-02 9 -4.91E-03 -1.25E-01 6.74E-02 -2.58E-02 2.15E-04 4.42E-03 -2.33E-03 10 -2.33E-02 2.53E-02 -4.52E-03 2.28E-04 -1.70E-04 -4.15E-05 1.05E-05 11 -1.10E-01 5.72E-02 -2.13E-04 -1.71E-03 -2.91E-04 -3.21E-05 2.18E-05 12 0.000 0.000 0.000 0.000 0.000 0.000 0.000
[0090] Figure 3 Schematic diagram of the imaging MTF of the micro-projection lens 100 described in this embodiment at 20° C. Figure 4 is a schematic diagram of the defocusing of the micro-projection lens 100 at 20° C. in this embodiment; Figure 5 Schematic diagram of the imaging MTF of the micro-projection lens 100 at 60° C. Figure 6 is a schematic diagram of the defocusing of the micro-projection lens 100 at 60° C. in this embodiment, Figure 7 is a schematic diagram of the field area of the micro-projection lens 100 in this embodiment, Figure 8 FIG. 1 is a schematic diagram showing the distortion of the micro-projection lens 100 in this embodiment.
[0091] Since the binocular display AR glasses need to combine the two eyes, if the micro-projection lens has a large distortion, it will affect the binocular combination and display effect of the final glasses. Figure 7-Figure 8 It can be seen that the lens under this architecture can compress the distortion to within 1.8%, with only a slight distortion effect.
[0092] The above description is only a preferred embodiment of the utility model, and does not limit the patent scope of the utility model. All equivalent structural changes made by using the contents of the utility model specification and drawings under the concept of the utility model, or directly / indirectly used in other related technical fields are included in the patent protection scope of the utility model.
Claims
1. A micro-projection lens, characterized in that: The micro-projection lens has an object side and an image side correspondingly arranged along the optical axis direction. The micro-projection lens includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from the object side to the image side. The focal length of the micro-projection lens is f, 5.9 mm <f<6.1mm; The first lens is a glass aspheric lens, and the second lens, the third lens, the fourth lens and the fifth lens are all plastic aspheric lenses.
2. The micro-projection lens according to claim 1, wherein: The first lens is a positive lens, and the object side surface of the first lens is convex, and the image side surface is concave; The second lens is a positive lens, and the object side surface of the second lens is convex, and the image side surface is concave; The third lens is a negative lens, and the object side surface and the image side surface of the third lens are concave; The fourth lens is a positive lens, and the object side surface of the fourth lens is a concave surface, and the image side surface is a convex surface; The fifth lens is a positive lens, and the object side surface of the fifth lens is a concave surface, and the image side surface is a convex surface.
3. The micro-projection lens according to claim 2, wherein: The semi-aperture of the first lens is d1, 1.6 mm <d1<1.8mm; The semi-aperture of the second lens is d2, 1.3 mm <d2<1.6mm; The semi-aperture of the third lens is d3, 1 mm <d3<1.3mm; The semi-aperture of the fourth lens is d4, 1.1 mm <d4<1.4mm; The semi-aperture of the fifth lens is d5, 1.6 mm <d5<1.9mm。 4. The micro-projection lens according to claim 2, wherein: The core thickness of the first lens is L1, 0.8 mm <L1<0.95mm; The core thickness of the second lens is L2, 0.95 mm <L2<1.1mm; The core thickness of the third lens is L3, 0.3 mm <L3<0.4mm; The core thickness of the fourth lens is L4, 0.35 mm <L4<0.45mm; The core thickness of the fifth lens is L5, 0.7 mm <L5<0.8mm。 5. The micro-projection lens according to claim 1, wherein: The refractive index of the first lens is n1,1.7 <n1<1.9; The refractive index of the second lens is n2,1.49 <n2<1.6; The refractive index of the third lens is n3,1.6 <n3<1.7; The refractive index of the fourth lens is n4,1.6 <n4<1.7; The refractive index of the fifth lens is n5, 1.55 <n5<1.65。 6. The micro-projection lens according to claim 1, wherein: The change amount of the micro-projection lens is △ft, the change amount of the back focus of the second lens is △f2, the change amount of the back focus of the third lens is △f3, the change amount of the back focus of the fourth lens is △f4, and the change amount of the back focus of the fifth lens is △f5. The micro-projection lens meets the following conditions: △ft=△f2+△f3+△f4+△f5<5um.
7. The micro-projection lens according to claim 1, wherein: The micro-projection lens further includes an aperture, and the aperture is arranged on a side of the first lens facing away from the second lens.
8. The micro-projection lens according to claim 7, wherein: The distance from the aperture to the image side is the total optical length TTL of the micro-projection lens, and TTL is less than 5.6 mm.
9. The micro-projection lens according to claim 7, wherein: The radius of the aperture is d0, 1 mm <d0<2.5mm。 10. The micro-projection lens according to claim 7, wherein: The distance from the aperture to the first lens is L0, and L0<1 mm.