An ultra-thin wide-angle small head AR lens and projection device

Abstract

The application relates to an AR lens with an ultrathin wide-angle small head and a projection device, the lens comprising: a first lens, a diaphragm, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from an object side to an image side, the first lens has positive focal power, the object side surface of the first lens is a convex surface, and the image side surface is a concave surface; the second lens has positive focal power, the object side surface of the second lens is a concave surface, and the image side surface is a convex surface; the third lens has negative focal power, the object side surface of the third lens is a convex surface, and the image side surface is a concave surface; the fourth lens has positive focal power, the object side surface of the fourth lens is a concave surface, and the image side surface is a convex surface; the fifth lens has negative focal power, the object side surface of the fifth lens is a convex surface, and the image side surface is a concave surface; the effective diameter D (P1) of the first lens satisfies 1.50 < D (P1) < 2.0; and the total optical length TTL of the AR lens satisfies 3.79 <= TTL <= 4.10. The application reduces the total length and cost of the AR lens and improves the resolution.

Description

Technical Field

[0001] This invention belongs to the field of optical projection equipment technology, specifically relating to an ultra-thin wide-angle small-head AR lens and device. Background Technology

[0002] With the rapid development of AR (Augmented Reality) technology, AR devices are evolving towards being thinner, clearer, and more comfortable, providing users with a better augmented reality experience. As a key component of AR devices, the AR lens (the optical system design of AR) faces challenges such as visual clarity, field of view optimization, eye tracking, and long-term wearing comfort. It requires the placement of complex optical elements within a limited space while ensuring image quality and user experience. Summary of the Invention

[0003] To address the challenges of miniaturization, improved resolution, reduced cost, and maintenance of other performance characteristics in AR lenses, a first aspect of this invention provides an ultra-thin, wide-angle, small-head AR lens, comprising: a first lens, an aperture stop, a second lens, a third lens, a fourth lens, and a fifth lens, arranged sequentially from the object side to the image side. The first lens has positive optical power, with its object side being convex and its image side being concave. The second lens has positive optical power, with its object side being concave and its image side being convex. The third lens has negative optical power, with its object side being convex and its image side being concave. The fourth lens has positive optical power, with its object side being concave and its image side being convex. The fifth lens has negative optical power, with its object side being convex and its image side being concave. The effective diameter D(P1) of the first lens satisfies: 1.50 < D(P1) < 2.0. The total optical length (TTL) of the AR lens satisfies: 3.79 ≤ TTL ≤ 4.10.

[0004] In some embodiments of this application, the radius of curvature R(L2S2) of the image-side surface L2S2 of the second lens and the focal length f of the lens satisfy: -0.521≤R(L2S2) / f≤-0.416.

[0005] In some embodiments of this application, the thickness T2 of the second lens and the focal length f of the lens satisfy: 0.20≤T2 / f≤0.25.

[0006] In some embodiments of this application, the focal length f2 of the second lens satisfies: 1.811≤f2≤2.20.

[0007] In some embodiments of this application, the focal length f4 of the fourth lens and the combined focal length f of the third and fourth lenses are... 34 Satisfies: 1.073 < f 34 / f4<1.213.

[0008] In some embodiments of this application, the radius of curvature R(L4S2) of the image-side surface L4S2 of the fourth lens and the focal length f4 of the fourth lens satisfy: -0.661≤R(L4S2)≤-0.604, 1.482≤f4≤2.111.

[0009] In the above embodiments, the order of the aspherical coefficients of the surfaces of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens is an even number.

[0010] Furthermore, the highest order of the aspherical coefficients on the surfaces of the first lens, second lens, third lens, fourth lens, and fifth lens is 16.

[0011] In the above embodiments, the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all made of plastic.

[0012] A second aspect of the present invention provides a projection device based on the AR projection lens provided in the first aspect of the present invention.

[0013] The beneficial effects of this application are:

[0014] This application features an alternating positive and negative structure: through a combination of "positive-positive-negative-positive-negative", it balances the optical power distribution and simultaneously corrects various aberrations (spherical aberration, field curvature, distortion, etc.). By placing the aperture between the first two positive lenses, aberration symmetry is optimized, improving system stability. Through the collaborative work of multiple lenses, a large field of view, low distortion, and high resolution are achieved in a compact structure, adapting to the lightweight requirements of AR devices. Attached Figure Description

[0015] Figure 1 These are schematic diagrams illustrating the structure of the AR lenses in Embodiments 1 to 7 of this application;

[0016] Figures 2 to 5 These are, respectively, the field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 1 of this application;

[0017] Figures 6 to 9 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 2 of this application are shown.

[0018] Figures 10 to 13 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 3 of this application are shown.

[0019] Figures 14 to 17 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 4 of this application are shown.

[0020] Figures 18 to 21 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 5 of this application are shown.

[0021] Figures 22 to 25 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment Six of this application are shown.

[0022] Figures 26 to 29 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment Seven of this application are shown.

[0023] Figures 30 to 33 The field curvature / distortion diagram, TV distortion diagram, MTF performance diagram, and MTF defocus curve diagram of the AR lens of Embodiment 8 of this application are shown.

[0024] Figure 34 This is a schematic diagram of the AR lens in Comparative Example 8.

[0025] Figure Labels

[0026] 101. First lens; 102. Aperture; L1 S1. Object-side surface of the first lens; L1 S2. Image-side surface of the first lens; 103. Second lens; L2S1. Object-side surface of the prism; L2S2. Image-side surface of the prism; 104. Third lens; L3S1. Object-side surface of the third lens; L3S2. Image-side surface of the third lens; 105. Fourth lens; L4S1. Object-side surface of the fourth lens; L4S2. Image-side surface of the fourth lens; 106. Fifth lens; L5S1. Object-side surface of the fifth lens; L5S2. Image-side surface of the fifth lens. Detailed Implementation

[0027] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] refer to Figure 1 and Figure 2In a first aspect of the present invention, an ultra-thin wide-angle small-head AR lens is provided, comprising: a first lens 101, an aperture 102, a second lens 103, a third lens 104, a fourth lens 105, and a fifth lens 106, sequentially from the object side to the image side; the first lens 101 having positive optical power, and the object side of the first lens 101 being convex and the image side being concave; the second lens 103 having positive optical power, and the object side of the second lens 103 being concave and the image side being convex; the third lens 104... The third lens 104 has negative optical power, and its object-side surface is convex while its image-side surface is concave. The fourth lens 105 has positive optical power, and its object-side surface is concave while its image-side surface is convex. The fifth lens 106 has negative optical power, and its object-side surface is convex while its image-side surface is concave. The effective diameter D(P1) of the first lens 101 satisfies: 1.50 < D(P1) < 2.0. The total optical length TTL of the AR lens satisfies: 3.79 ≤ TTL ≤ 4.10.

[0029] It should be noted that the determination of surface shape in the paraxial region can be based on the common practice among those knowledgeable in the field, using the R value (R refers to the radius of curvature of the paraxial region, usually the R value in the lens data database of optical software) to determine concavity or convexity. For the object side, a positive R value indicates a convex surface, and a negative R value indicates a concave surface; for the image side, a positive R value indicates a concave surface, and a negative R value indicates a convex surface.

[0030] In the accompanying drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not drawn strictly to scale.

[0031] The following description, with reference to the accompanying drawings, further illustrates specific surface shapes and parameters of AR lenses applicable to the above embodiments. It should be noted that any one of the following embodiments, from Embodiment 1 to Embodiment 7, is applicable to all embodiments of this application. Embodiment 8 serves as a comparative example.

[0032] Example 1

[0033] The lens structure parameters of the first embodiment are as follows:

[0034]

[0035] The aspheric coefficients of the first embodiment are as follows:

[0036]

[0037] The formula for aspherical surfaces is as follows:

[0038]

[0039] Where z represents the point on the aspherical surface at a distance h from the optical axis, and its relative distance to the tangent plane at the vertex on the optical axis of the aspherical surface; c represents the radius of curvature; h represents the distance between the point on the aspherical surface and the optical axis; k represents the conic coefficient; and Ai represents the i-th order aspherical coefficient. Substituting the aspherical coefficients of each surface into the aspherical formula yields the surface curve (structure), as illustrated in the structural diagram of the embodiment.

[0040] The feature parameter values ​​for the first embodiment are as follows:

[0041]

[0042] Feature parameter description:

[0043] R(L2S2) is the radius of curvature of the L2S2 surface of the second lens. R(L4S2) is the radius of curvature of the L4S2 surface of the fourth lens. f34 is the focal length of the third and fourth combined lenses. f2 is the focal length of the second lens. f4 is the focal length of the fourth lens. f is the lens focal length (focal length is a measure of the convergence or divergence of light in an optical system, referring to the distance from the optical center of the lens to the focal point where parallel light converges when incident). T2 is the core thickness of the second lens (the distance on the central optical axis from the center point of the L2S1 surface to the center point of the L2S2 surface). TTL is the total optical length of the lens optical system (the distance on the central optical axis from the center point of the L1S1 surface to the center point of the image plane). DFOV is the field of view angle (in optical instruments, the angle between the two edges of the maximum range through which the image of the target can pass through the lens, with the lens of the optical instrument as the vertex, is called the field of view angle). Optical DIS is the optical distortion value, which is the ratio of the theoretical difference between the ideal image height and the actual image height to the actual image height. TV DIS is the TV distortion value, which is the ratio of the maximum difference in image height between objects of the same height on the object side and the maximum image height on the image side. D(P1) is the effective diameter of P1, which is the diameter of the optically effective area of ​​the first lens element. Reducing the effective diameter of P1 allows for miniaturization of the lens head structure.

[0044] Example 2

[0045] The lens structure parameters of the second embodiment are as follows:

[0046]

[0047] The aspheric coefficients of the second embodiment are as follows:

[0048]

[0049] The feature parameter values ​​of the second embodiment are as follows:

[0050]

[0051] Example 3

[0052] The lens structure parameters of the third embodiment are as follows:

[0053]

[0054]

[0055] The aspheric coefficients of the third embodiment are as follows:

[0056]

[0057] The feature parameter values ​​of the third embodiment are as follows:

[0058]

[0059]

[0060] Example 4

[0061] The lens structure parameters of the fourth embodiment are as follows:

[0062]

[0063] The aspheric coefficients of the fourth embodiment are as follows:

[0064]

[0065]

[0066] The characteristic parameter values ​​of the fourth embodiment are as follows:

[0067]

[0068] Example 5

[0069] The lens structure parameters of the fifth embodiment are as follows:

[0070]

[0071] The aspheric coefficients of the fifth embodiment are as follows:

[0072]

[0073] The characteristic parameter values ​​of the fifth embodiment are as follows:

[0074]

[0075] Example 6

[0076] The lens structure parameters of the sixth embodiment are as follows:

[0077]

[0078]

[0079] The aspheric coefficients of the sixth embodiment are as follows:

[0080]

[0081] The characteristic parameter values ​​of the sixth embodiment are as follows:

[0082]

[0083] Example 7

[0084] The lens structure parameters of the seventh embodiment are as follows:

[0085]

[0086] The aspheric coefficients of the seventh embodiment are as follows:

[0087]

[0088]

[0089] The characteristic parameter values ​​of the seventh embodiment are as follows:

[0090]

[0091] Example 8

[0092] The lens structure parameters of the eighth embodiment are as follows:

[0093]

[0094] The aspheric coefficients of the eighth embodiment are as follows:

[0095]

[0096] The characteristic parameter values ​​of the eighth embodiment are as follows:

[0097]

[0098] A second aspect of the present invention provides a projection device based on the AR projection lens provided in the first aspect of the present invention.

[0099] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0100] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultra-thin wide-angle, small-head AR lens, characterized in that, include: From the object side to the image side, it includes a first lens, an aperture, a second lens, a third lens, a fourth lens, and a fifth lens in sequence. The first lens has positive optical power, and the object side of the first lens is convex, while the image side is concave. The second lens has positive optical power, and its object-side surface is concave while its image-side surface is convex; the focal length of the second lens... f 2. Satisfies: 1.811≤ f 2≤2.20; The thickness T2 of the second lens and the focal length of the lens f Satisfy: 0.20≤ T 2 / f ≤0.25; The third lens has negative optical power, and the object side of the third lens is convex, while the image side is concave. The fourth lens has positive optical power, and the object side of the fourth lens is concave, while the image side is convex. The fifth lens has negative optical power, and the object side of the fifth lens is convex, while the image side is concave. The effective diameter D(P1) of the first lens satisfies: 1.50 < D(P1) < 2.0; the total optical length TTL of the AR lens satisfies: 3.79 ≤ TTL ≤ 4.10; The aspherical coefficients of the surfaces of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all of even order; the highest order of the aspherical coefficients of the surfaces of the first lens, the second lens, the third lens, the fourth lens, and the fifth lens is 16; the first lens, the second lens, the third lens, the fourth lens, and the fifth lens are all made of plastic.

2. The ultra-thin wide-angle small-head AR lens according to claim 1, characterized in that, The radius of curvature R(L2S2) of the image-side surface L2S2 of the second lens is related to the focal length of the lens. f Satisfying: -0.521≤R(L2S2) / f ≤-0.

416.

3. The ultra-thin wide-angle small-head AR lens according to claim 1, characterized in that, The focal length of the fourth lens f 4. The combined focal length of the third and fourth lenses f 34 Satisfies: 1.073 < f 34 / f 4 < 1.

213.

4. The ultra-thin wide-angle small-head AR lens according to claim 1, characterized in that, The radius of curvature R(L4S2) of the image-side surface L4S2 of the fourth lens, and the focal length of the fourth lens. f 4. Satisfies: -0.661≤R(L4S2)≤-0.604, 1.482≤ f 4≤2.

111.

5. An AR projection device, characterized in that, The AR projection device includes the AR lens according to any one of claims 1 to 4.

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