Optical system and VR device comprising the same

Abstract

The present application discloses an optical system and a VR device including the optical system. The optical system sequentially includes, along the optical axis, from the first side to the second side: a first lens with positive optical power; a second lens with positive optical power, whose second side is convex; and a third lens with positive optical power, whose first side is concave and second side is convex. The optical system further includes a reflective polarizing element and a quarter-wave plate attached to either the first side or the second side of the first lens. The effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate satisfy 0.04 < f / fz < 0.16; the effective semi-aperture T1a1 from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, the effective semi-aperture T1c1 from the optical center of the first side of the first lens to the lower edge of the effective diameter profile of the first side of the first lens, and the effective focal length f of the optical system satisfy 1.5 < (T1a1 + T1c1) / f < 2.2.

Description

Technical Field

[0001] This application relates to the field of optical elements, and more specifically, to an optical system and a VR device including the optical system. Background Art

[0002] With the proposal of the concept of "metaverse", virtual reality technology (VR) has gradually entered people's lives. Based on the technical integration of computer algorithms, graphics processing, optical display, etc., a three-dimensional dynamic visual scene has been gradually established and has interactive functions. At present, on the one hand, VR devices can well meet the practical requirements of people's lives and have greatly increased the comfort of use; on the other hand, the early aspherical or Fresnel lenses had a relatively long body, resulting in the center of gravity of the VR device being forward, and the user experience was not good, so a folding optical system was proposed.

[0003] The folding optical system can compress the length of the entire lens to a great extent through the folding of the optical path, so that the center of gravity of the VR device moves backward, further increasing the comfort of use for consumers. However, the current folding optical system still needs to further reduce the size and weight, and further improve the user experience to meet the high requirements of the market and consumers. For a three-piece folding optical system, those skilled in the art expect to optimize the optical parameters of the first lens closest to the user or the side closest to the human eye to further improve its control of the light exit angle, while ensuring its outer diameter size and processability, reducing the system volume, and further enhancing the user's immersive experience. Summary of the Invention

[0004] This application provides an optical system, which may sequentially include, along the optical axis from the first side to the second side: a first lens with positive optical power; a second lens with positive optical power, the second side of which is convex; and a third lens with positive optical power, the first side of which is concave and the second side of which is convex; the optical system further includes: a reflective polarizing element and a quarter-wave plate, and the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens. The optical system can satisfy: 0.04 < f / fz < 0.16 and 1.5 < (T1a1 + T1c1) / f < 2.2, where f is the effective focal length of the optical system, fz is the combined focal length of the first lens, the reflective polarizing element and the quarter-wave plate, T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter contour of the first side of the first lens, and T1c1 is the effective semi-aperture from the optical center of the first side of the first lens to the lower edge of the effective diameter contour of the first side of the first lens.

[0005] In one embodiment, the effective half-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective radial profile of the first side of the first lens and the center thickness CT1 of the first lens on the optical axis can satisfy: 2.7 <T1b1 / CT1<4.7。

[0006] In one embodiment, the effective focal length f1 of the first lens, the effective half-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens, and the effective half-aperture T1d2 from the optical center of the second side of the first lens to the right edge of the effective radial profile of the second side of the first lens can satisfy: 1.6 <f1 / (T1a2+T1b2+T1c2+T1d2)<6.1。

[0007] In one embodiment, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis can satisfy: 1.1 < (CT2 + CT3) / (CT1 + CTR + CTQ) < 2.0.

[0008] In one embodiment, the entrance pupil diameter (EPD) of the optical system can satisfy: 3.1 <T1a1 / EPD<4.3。

[0009] In one embodiment, the effective half-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective radial profile of the first side of the first lens, the effective half-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective radial profile of the first side of the first lens, and the distance TD from the first side of the first lens to the second side of the third lens on the optical axis can satisfy: 2.0 < (T1b1 + T1d1) / TD < 3.2.

[0010] In one embodiment, the refractive index N1 of the first lens and the effective half-aperture T1d1 from the optical center of the first side surface of the first lens to the right edge of the effective radial profile of the first side surface of the first lens can satisfy: 1.1 <N1×(T1a1 / T1d1)<1.4。

[0011] In one embodiment, the effective semi-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective diameter contour of the second side of the first lens, the effective semi-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter contour of the second side of the first lens, and the maximum semi-field angle Semi-FOV of the optical system satisfy: 1.5 < (T1a2 + T1c2) / (f × tan(Semi-FOV)) < 2.0.

[0012] In one embodiment, the effective focal length f3 of the third lens, the radius of curvature R5 of the first side of the third lens, and the radius of curvature R6 of the second side of the third lens satisfy: -4.8 < f3 / (R5 + R6) < -0.1.

[0013] In one embodiment, the radius of curvature R4 of the second side of the second lens and the effective focal length f2 of the second lens satisfy: -1.1 < R4 / f2 < -0.1.

[0014] In one embodiment, the refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective semi-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective diameter contour of the second side of the first lens satisfy: 18.2 mm < (NR / NQ) × T1b2 < 23.3 mm.

[0015] On the other hand, the present application also provides an optical system. The optical system may sequentially include, from the first side to the second side along the optical axis: a first lens with a positive optical power; a second lens with a positive optical power, the second side of which is convex; and a third lens with a positive optical power, the first side of which is concave and the second side of which is convex. The optical system may further include: a reflective polarizing element and a quarter-wave plate, and the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens. The optical system satisfies 0.04 < f / fz < 0.16 and 3.1 < T1a1 / EPD < 4.3, where f is the effective focal length of the optical system, fz is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter contour of the first side of the first lens, and EPD is the entrance pupil diameter of the optical system.

[0016] In one embodiment, the effective semi-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective diameter contour of the first side of the first lens and the central thickness CT1 of the first lens on the optical axis satisfy: 2.7 < T1b1 / CT1 < 4.7.

[0017] In one embodiment, the effective focal length f1 of the first lens, the effective half-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens, and the effective half-aperture T1d2 from the optical center of the second side of the first lens to the right edge of the effective radial profile of the second side of the first lens can satisfy: 1.6 <f1 / (T1a2+T1b2+T1c2+T1d2)<6.1。

[0018] In one embodiment, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis can satisfy: 1.1 < (CT2 + CT3) / (CT1 + CTR + CTQ) < 2.0.

[0019] In one embodiment, the effective half-aperture T1c1 from the optical center of the first side of the first lens to the lower edge of the effective diameter profile of the first side of the first lens can satisfy: 1.5 < (T1a1 + T1c1) / f < 2.2.

[0020] In one embodiment, the effective half-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective radial profile of the first side of the first lens, the effective half-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective radial profile of the first side of the first lens, and the distance TD from the first side of the first lens to the second side of the third lens on the optical axis can satisfy: 2.0 < (T1b1 + T1d1) / TD < 3.2.

[0021] In one embodiment, the refractive index N1 of the first lens and the effective half-aperture T1d1 from the optical center of the first side surface of the first lens to the right edge of the effective radial profile of the first side surface of the first lens can satisfy: 1.1 <N1×(T1a1 / T1d1)<1.4。

[0022] In one embodiment, the effective semi-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, the effective semi-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, and the maximum semi-field angle Semi-FOV of the optical system satisfy: 1.5 < (T1a2 + T1c2) / (f × tan(Semi-FOV)) < 2.0.

[0023] In one embodiment, the effective focal length f3 of the third lens, the radius of curvature R5 of the first side of the third lens, and the radius of curvature R6 of the second side of the third lens satisfy: -4.8 < f3 / (R5 + R6) < -0.1.

[0024] In one embodiment, the radius of curvature R4 of the second side of the second lens and the effective focal length f2 of the second lens satisfy: -1.1 < R4 / f2 < -0.1.

[0025] In one embodiment, the refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective semi-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective diameter profile of the second side of the first lens satisfy: 18.2 mm < (NR / NQ) × T1b2 < 23.3 mm.

[0026] In another aspect, the present application further provides a VR device, which includes the optical system provided in any one of the above embodiments. Among them, the first side is the human eye side, and the second side is the display side.

[0027] The optical system disclosed in the present application sequentially includes a first lens with a positive optical power, a second lens with a positive optical power, and a third lens with a positive optical power along the optical axis from the first side to the second side. Among them, the second side of the second lens is convex, the first side of the third lens is concave, and the second side is convex. A reflective polarizing element and a quarter-wave plate are attached to the first side or the second side of the first lens. The optical system has a positive-positive-positive optical architecture. At the same time, it is controlled that the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate satisfy 0.04 < f / fz < 0.16. Under this prerequisite, by controlling the effective semi-aperture T1a1 from the optical center of the first side of the first lens to the upper edge of the effective diameter profile, the effective semi-aperture T1c1 from the optical center of the first side of the first lens to the lower edge of the effective diameter profile, and the effective focal length f of the optical system satisfy 1.5 < (T1a1 + T1c1) / f < 2.2, it is beneficial to control the light exit angle of the first lens and ensure the outer diameter size and processability of the entire lens. Attached Figure Description

[0028] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0029] Figure 1 Schematic diagrams of the optical systems according to Embodiments 1, 2 and 3 of this application are shown;

[0030] Figure 2 , Figure 3 and Figure 4 The on-axis chromatic aberration curves, astigmatism curves, and distortion curves of the optical systems of Embodiments 1, 2, and 3 are shown respectively.

[0031] Figure 5 Schematic diagrams of the optical systems according to Embodiments 4, 5 and 6 of this application are shown;

[0032] Figure 6 , Figure 7 and Figure 8 The on-axis chromatic aberration curves, astigmatism curves, and distortion curves of the optical systems of Examples 4, 5, and 6 are shown respectively.

[0033] Figure 9 Schematic diagrams of the optical systems according to Embodiments 7, 8 and 9 of this application are shown;

[0034] Figure 10 , Figure 11 and Figure 12 The on-axis chromatic aberration curves, astigmatism curves, and distortion curves of the optical systems of Examples 7, 8, and 9 are shown respectively.

[0035] Figure 13 A schematic diagram showing the effective half-aperture in the directions a1, b1, c1, d1 of the first side surface of the first lens in an optical system according to an exemplary embodiment of this application is shown; and

[0036] Figure 14 A schematic diagram of the effective half-aperture in the directions a2, b2, c2, d2 of the second side surface of the first lens in an optical system according to an exemplary embodiment of this application is shown. Detailed Implementation

[0037] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0038] It should be noted that in this specification, the terms "first," "second," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first optical lens discussed below may also be referred to as the second optical lens, and the second optical lens may also be referred to as the first optical lens.

[0039] 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 strictly to scale.

[0040] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region.

[0041] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0042] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] The features, principles and other aspects of this application are described in detail below.

[0045] An optical system according to an exemplary embodiment of this application may include a first lens, a second lens, and a third lens arranged sequentially along an optical axis from a first side to a second side, wherein the first lens may have positive optical power, the second lens may have positive optical power, and the third lens may have positive optical power.

[0046] In an exemplary embodiment, the second side surface of the second lens can be a convex surface. The first side surface of the third lens can be a concave surface, and the second side surface can be a convex surface.

[0047] In an exemplary embodiment, the optical system may further include a reflective polarizing element and a quarter-wave plate. The reflective polarizing element and the quarter-wave plate may be attached to a first side or a second side of the first lens.

[0048] In an exemplary embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display side. The optical system may be used, for example, in a VR device.

[0049] The following will refer to Figure 1 An exemplary description of the optical system is provided. For example... Figure 1 As shown, an optical system according to an exemplary embodiment of this application may include a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a third lens E3, and a partially reflective element BS arranged sequentially from a first side to a second side, wherein the reflective polarizing element RP and the quarter-wave plate QWP are attached to the second side of the first lens. In practical use, the optical system according to an exemplary embodiment of this application can be used as a VR lens, where the first side corresponds to the human eye side and the second side corresponds to the display side. The optical system may also include an image plane IMG located on the second side (e.g., the display side). A light beam emitted from the image plane IMG passes sequentially through a partial reflective element BS, a third lens E3, a second lens E2, and a quarter-wave plate QWP to reach a reflective polarizing element RP. At the reflective polarizing element RP, the beam is reflected and passes again through the quarter-wave plate QWP, the second lens E2, and the third lens E3 to reach the partial reflective element BS. Then, the beam is reflected again at the partial reflective element BS and passes sequentially through the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 before exiting towards a first side (e.g., the human eye side). In an exemplary embodiment, the partial reflective element BS may be a semi-transparent, semi-reflective film layer coated on the second or first side of the third lens E3.

[0050] In an exemplary embodiment, the effective half-aperture of the first side surface of the first lens in the directions a1, b1, c1, d1 is as follows: Figure 13As shown, specifically, the effective semi-aperture from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile of the first side surface of the first lens is T1a1; the effective semi-aperture from the optical center of the first side surface of the first lens to the left edge of the effective diameter profile of the first side surface of the first lens is T1b1; the effective semi-aperture from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens is T1c1; the effective semi-aperture from the optical center of the first side surface of the first lens to the right edge of the effective diameter profile of the first side surface of the first lens is T1d1.

[0051] In an exemplary embodiment, the effective semi-apertures of the second side surface of the first lens in the a2, b2, c2, d2 directions are as Figure 14 shown. Specifically, the effective semi-aperture from the optical center of the second side surface of the first lens to the upper edge of the effective diameter profile of the second side surface of the first lens is T1a2; the effective semi-aperture from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens is T1b2; the effective semi-aperture from the optical center of the second side surface of the first lens to the lower edge of the effective diameter profile of the second side surface of the first lens is T1c2; the effective semi-aperture from the optical center of the second side surface of the first lens to the right edge of the effective diameter profile of the second side surface of the first lens is T1d2.

[0052] In an exemplary embodiment, the optical system of the present application can satisfy the conditional expression 0.04 < f / fz < 0.16, where f is the effective focal length of the optical system, and fz is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate.

[0053] In an exemplary embodiment, the optical system of the present application can satisfy the conditional expression 1.5 < (T1a1 + T1c1) / f < 2.2, where T1a1 is the effective semi-aperture from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile of the first side surface of the first lens, T1c1 is the effective semi-aperture from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens, and f is the effective focal length of the optical system.

[0054] An optical system according to an exemplary embodiment of the present application sequentially includes, from the first side to the second side along the optical axis, a first lens with positive optical power, a second lens with positive optical power, and a third lens with positive optical power. Among them, the second side surface of the second lens is convex, the first side surface of the third lens is concave, and the second side surface is convex. A reflective polarizing element and a quarter-wave plate are attached to either the first side or the second side of the first lens. The optical system has a positive-positive-positive optical architecture. At the same time, it is controlled that the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate satisfy 0.04 < f / fz < 0.16. Under this prerequisite, by controlling the effective semi-aperture T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter contour, the effective semi-aperture T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter contour, and the effective focal length f of the optical system satisfy 1.5 < (T1a1 + T1c1) / f < 2.2, it is beneficial to control the light exit angle of the first lens and ensure the outer diameter size and processability of the entire lens.

[0055] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 2.7 < T1b1 / CT1 < 4.7, where T1b1 is the effective semi-aperture from the optical center of the first side surface of the first lens to the left edge of the effective diameter contour of the first side surface of the first lens, and CT1 is the central thickness of the first lens on the optical axis. By controlling the ratio of the effective semi-aperture from the optical center of the first side surface of the first lens to the left edge of the effective diameter contour of the first side surface of the first lens to the central thickness of the first lens on the optical axis within this range, the outer diameter size of the lens and the ratio of the thickness to the thinness of the lens can be reasonably restricted, which is beneficial to the molding of the lens and is also beneficial to realizing the lightness and thinness of the entire VR device.

[0056] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 1.6 < f1 / (T1a2 + T1b2 + T1c2 + T1d2) < 6.1, where f1 is the effective focal length of the first lens, T1a2 is the effective semi-aperture from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, T1b2 is the effective semi-aperture from the optical center of the second side of the first lens to the left edge of the effective diameter profile of the second side of the first lens, T1c2 is the effective semi-aperture from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, and T1d2 is the effective semi-aperture from the optical center of the second side of the first lens to the right edge of the effective diameter profile of the second side of the first lens. By controlling the effective focal length f1 of the first lens and the effective semi-apertures from the optical center of the second side of the first lens to the edges in different directions (upper, lower, left, and right) of the effective diameter profile to satisfy the conditional formula 1.6 < f1 / (T1a2 + T1b2 + T1c2 + T1d2) < 6.1, on the one hand, it can ensure that the lens is not too curved; on the other hand, it can ensure the outer diameter size of the lens. Both of these are beneficial to the formability of the lens and the thinning of the entire VR device.

[0057] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 1.1 < (CT2 + CT3) / (CT1 + CTR + CTQ) < 2.0, where CT2 is the central thickness of the second lens on the optical axis, CT3 is the central thickness of the third lens on the optical axis, CT1 is the central thickness of the first lens on the optical axis, CTR is the central thickness of the reflective polarizing element on the optical axis, and CTQ is the central thickness of the quarter-wave plate on the optical axis. By reasonably controlling the central thicknesses of the first lens, the second lens, the third lens, the reflective polarizing element, and the quarter-wave plate on the optical axis, the air gap between the lenses can be restricted, and the length of the entire optical system can be reduced, which is beneficial to the thinning of the VR device.

[0058] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 3.1 < T1a1 / EPD < 4.3, where T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, and EPD is the entrance pupil diameter of the optical system. By controlling the ratio of the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter profile to the entrance pupil diameter, the entrance pupil diameter can be increased on the premise of a certain effective diameter size, which is beneficial to improving the performance degradation caused by pupil offset when the human eye rotates, thereby improving the comfort during visual inspection.

[0059] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 2.0 < (T1b1 + T1d1) / TD < 3.2, where T1b1 is the effective semi-aperture from the optical center of the first side of the first lens to the left edge of the effective diameter profile of the first side of the first lens, T1d1 is the effective semi-aperture from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens, and TD is the distance on the optical axis from the first side of the first lens to the second side of the third lens. By controlling the optical system to satisfy the conditional formula 2.0 < (T1b1 + T1d1) / TD < 3.2, the overall length dimension of the visual system can be effectively constrained, which is beneficial for later matching with the module; at the same time, by constraining the outer dimension of the first lens, on the premise of ensuring the processability of the lens, the overall outer dimension of the entire optical lens can be minimized, thereby reducing the overall machine size.

[0060] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 1.1 < N1 × (T1a1 / T1d1) < 1.4, where N1 is the refractive index of the first lens, T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, and T1d1 is the effective semi-aperture from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens. By controlling the optical system to satisfy the conditional formula 1.1 < N1 × (T1a1 / T1d1) < 1.4, the outer dimension of the first lens can be ensured, and the refractive index of the first lens can be controlled, so as to select materials with low refractive index and low stress, thereby reducing the influence of stress on the polarization state of the entire optical system.

[0061] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 1.5 < (T1a2 + T1c2) / (f × tan(Semi-FOV)) < 2.0, where T1a2 is the effective semi-aperture from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, T1c2 is the effective semi-aperture from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, f is the effective focal length of the optical system, and Semi-FOV is the maximum semi-field angle of the optical system. By controlling the optical system to satisfy the conditional formula 1.5 < (T1a2 + T1c2) / (f × tan(Semi-FOV)) < 2.0, the field angle of the entire system can be effectively controlled, so that the system meets the characteristics of a large field angle of a VR lens; at the same time, the optical performance of the system and the outer diameter dimension of the entire device can be reasonably allocated, increasing the sense of use experience.

[0062] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula -4.8 < f3 / (R5 + R6) < -0.1, where f3 is the effective focal length of the third lens, R5 is the radius of curvature of the first side surface of the third lens, and R6 is the radius of curvature of the second side surface of the third lens. By controlling the radii of curvature of the first and second side surfaces of the third lens and the effective focal length of the third lens to satisfy the conditional formula -4.8 < f3 / (R5 + R6) < -0.1, it is beneficial to control the light exit angle of the third lens, synchronize the back focal length of the control system, and thus control the total length of the system to meet the miniaturization goal of the VR device.

[0063] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula -1.1 < R4 / f2 < -0.1, where R4 is the radius of curvature of the second side surface of the second lens and f2 is the effective focal length of the second lens. By controlling the ratio of the radius of curvature of the second side surface of the second lens to the effective focal length of the second lens within this range, the shape of the second lens is constrained, which is beneficial to reducing the sensitivity of the second lens and thus improving the yield of assembly.

[0064] In an exemplary embodiment, the optical system of the present application can satisfy the conditional formula 18.2mm < (NR / NQ)×T1b2 < 23.3mm, where NR is the refractive index of the reflective polarizing element, NQ is the refractive index of the quarter-wave plate, and T1b2 is the effective semi-aperture from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens. By controlling the optical system to satisfy the conditional formula 18.2mm < (NR / NQ)×T1b2 < 23.3mm, the refractive indices of the reflective polarizing element and the quarter-wave plate are made close to each other, which is beneficial to reducing the influence on the optical system when the thicknesses of the reflective polarizing element and the quarter-wave plate change, and increasing the selectivity of the polarization element.

[0065] In an exemplary embodiment, the optical system of the present application may include at least one aperture stop. The aperture stop can restrict the light path and control the light intensity. The aperture stop can be set at an appropriate position in the optical system. For example, the aperture stop can be located between the first side (such as the human eye side) and the first lens.

[0066] In an exemplary embodiment, optionally, the above optical system may further include a protective glass for protecting the photosensitive element located on the imaging surface.

[0067] An optical system according to an exemplary embodiment of the present application includes, in order from the first side to the second side along the optical axis, a first lens with a positive optical power, a second lens with a positive optical power, and a third lens with a positive optical power. Among them, the second side surface of the second lens is convex, the first side surface of the third lens is concave, and the second side surface is convex. A reflective polarizing element and a quarter-wave plate are attached to either the first side or the second side of the first lens. The optical system has a positive-positive-positive optical architecture. At the same time, it is controlled that the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate satisfy 0.04 < f / fz < 0.16. Under this prerequisite, by controlling the effective semi-aperture T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile and the effective semi-aperture T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile to satisfy 1.5 < (T1a1 + T1c1) / f < 2.2 with the effective focal length f of the optical system, it is beneficial to control the light exit angle of the first lens and ensure the outer diameter size and processability of the entire lens.

[0068] On the other hand, an optical system according to an exemplary embodiment of the present application includes, in order from the first side to the second side along the optical axis, a first lens with a positive optical power, a second lens with a positive optical power, and a third lens with a positive optical power. Among them, the second side surface of the second lens is convex, the first side surface of the third lens is concave, and the second side surface is convex. A reflective polarizing element and a quarter-wave plate are attached to either the first side or the second side of the first lens. The optical system has a positive-positive-positive optical architecture. At the same time, it is controlled that the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate satisfy 0.04 < f / fz < 0.16. Under this prerequisite, by controlling the effective semi-aperture T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile of the first side surface of the first lens to satisfy 3.1 < T1a1 / EPD < 4.3 with the entrance pupil diameter EPD of the optical system, it is possible to increase the entrance pupil diameter on the premise of a certain effective diameter size, which is beneficial to improving the performance degradation caused by pupil offset when the human eye rotates, thereby improving the comfort during visual inspection.

[0069] The following further describes specific embodiments of the optical system applicable to the above embodiments with reference to the drawings.

[0070] Example 1

[0071] The following refers to Figures 1 to 4 Describe the optical system according to Embodiment 1 of the present application. Figure 1 A schematic structural diagram of the optical system according to Embodiment 1 of the present application is shown.

[0072] As Figure 1As shown, the optical system includes, in sequence from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a third lens E3, and a partially reflective element BS.

[0073] In this embodiment, the first lens E1 has positive optical power, with a first convex surface and a second flat surface. The second lens E2 has positive optical power, with both its first and second sides being convex. The third lens E3 has positive optical power, with its first concave surface and second convex surface.

[0074] In this embodiment, the light beam emitted from the image plane IMG located on the second side can sequentially pass through the partial reflective element BS, the third lens E3, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizing element RP. It is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP, the second lens E2, and the third lens E3 again to reach the partial reflective element BS. After that, the light beam is reflected again at the partial reflective element BS and sequentially passes through the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit towards the first side.

[0075] In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP can be attached to the second side of the first lens E1. Specifically, the first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the second side of the third lens E3.

[0076] Table 1 shows the basic parameters of the optical system of Example 1, where the units for radius of curvature and thickness are millimeters (mm).

[0077]

[0078]

[0079] Table 1

[0080] In Embodiment 1, the first side surface S2 of the first lens E1, the first side surface S6 and the second side surface S7 of the second lens E2, and the first side surface S8 and the second side surface S9 of the third lens E3 are all aspherical surfaces. The surface shape x of the aspherical lens can be defined using, but is not limited to, the following aspherical formula:

[0081]

[0082] Where x is the distance vector from the vertex of the aspherical surface at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the higher-order coefficients A4, A6, A8, A9 that can be used for the aspherical mirrors S2, S6-S9 in Example 1. 10 A 12 A 14 A 16 A 18 and A 20 .

[0083] coefficient\surface S2 S6 S7 S8 S9 A4 5.4237E-06 -1.5885E-06 1.0446E-06 -9.2231E-07 2.8132E-07 A6 -2.3989E-09 -2.0729E-09 1.1980E-09 -1.5926E-09 -2.8440E-10 A8 3.6552E-12 -2.6708E-12 8.8833E-13 -1.6433E-12 -1.4642E-12 A10 0.0000E+00 -8.1094E-15 0.0000E+00 0.0000E+00 0.0000E+00 A12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A14 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A16 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A18 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A20 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0084] Table 2

[0085] Example 2

[0086] The optical system according to Embodiment 2 of this application has the same structure as the optical system described in Embodiment 1, and sequentially includes, from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a third lens E3, and a partially reflective element BS. The first lens E1 has positive optical power, with a convex first side and a flat second side. The second lens E2 has positive optical power, with a convex first side and a convex second side. The third lens E3 has positive optical power, with a concave first side and a convex second side. The first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the second side of the third lens E3. A light beam emitted from the image plane IMG located on the second side passes sequentially through the partial reflector BS, the third lens E3, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizer RP. At the reflective polarizer RP, the beam is reflected and passes again through the quarter-wave plate QWP, the second lens E2, and the third lens E3 to reach the partial reflector BS. Then, the beam is reflected again at the partial reflector BS and passes sequentially through the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, and the first lens E1 before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as in Table 1, and the table of higher-order coefficients of the aspherical mirror is the same as in Table 2.

[0087] The difference between this embodiment and Embodiment 1 is that the effective half-aperture values ​​T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1 are different, and the effective half-aperture values ​​T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2 are different. Specifically, T1a1 is the effective half-aperture from the optical center of the first side of the first lens to the upper edge of the effective radial profile of the first side of the first lens; T1b1 is the effective half-aperture from the optical center of the first side of the first lens to the left edge of the effective radial profile of the first side of the first lens; T1c1 is the effective half-aperture from the optical center of the first side of the first lens to the lower edge of the effective radial profile of the first side of the first lens; T1d1 is the effective half-aperture from the optical center of the first side of the first lens to the right edge of the effective radial profile of the first side of the first lens; T1a2 is the effective half-aperture from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens; T1b2 is the effective half-aperture from the optical center of the second side of the first lens to the left edge of the effective radial profile of the second side of the first lens; T1c2 is the effective half-aperture from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens; and T1d2 is the effective half-aperture from the optical center of the second side of the first lens to the right edge of the effective radial profile of the second side of the first lens. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment and Embodiment 1 are shown in Table 7 below.

[0088] Example 3

[0089] The optical system according to Embodiment 3 of this application has the same structure as the optical system described in Embodiment 1, and sequentially includes, from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a third lens E3, and a partially reflective element BS. The first lens E1 has positive optical power, with a convex first side and a flat second side. The second lens E2 has positive optical power, with a convex first side and a convex second side. The third lens E3 has positive optical power, with a concave first side and a convex second side. The first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the second side of the third lens E3. A light beam emitted from the image plane IMG located on the second side passes sequentially through the partial reflector BS, the third lens E3, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizer RP. It is reflected at the reflective polarizer RP and passes again through the quarter-wave plate QWP, the second lens E2, and the third lens E3 to reach the partial reflector BS. Then, the light beam is reflected again at the partial reflector BS and passes sequentially through the third lens E3, the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, and the first lens E1 before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as in Table 1, and the table of higher-order coefficients of the aspherical mirror is also the same as in Table 2.

[0090] The difference between this embodiment and Embodiment 1 lies in the different values ​​of the effective half-apertures T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1, and the different values ​​of the effective half-apertures T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment are also shown in Table 7 below.

[0091] Figure 2 The on-axis chromatic aberration curves of the optical systems of Embodiments 1, 2 and 3 are shown, which represent the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 3 Astigmatism curves of the optical systems of Embodiments 1, 2, and 3 are shown, representing meridional and sagittal image plane curvature. Figure 4 The distortion curves of the optical systems of Embodiments 1, 2, and 3 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 2 to 4 It can be seen that the optical systems given in Examples 1, 2 and 3 can achieve good imaging quality.

[0092] Example 4

[0093] The following is for reference Figures 5 to 8 The optical system according to Embodiment 4 of this application is described. Figure 5 A schematic diagram of the structure of an optical system according to Embodiment 4 of this application is shown.

[0094] like Figure 5 As shown, the optical system includes, in sequence from the first side to the second side along the optical axis: a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, a third lens E3, and a partially reflective element BS.

[0095] In this embodiment, the first lens E1 has positive optical power, with a first side surface that is flat and a second side surface that is convex. The second lens E2 has positive optical power, with a first side surface that is concave and a second side surface that is convex. The third lens E3 has positive optical power, with a first side surface that is concave and a second side surface that is convex.

[0096] In this embodiment, the light beam emitted from the image plane IMG located on the second side can sequentially pass through the partial reflective element BS, the third lens E3, the second lens E2, the first lens E1, and the quarter-wave plate QWP to reach the reflective polarizing element RP. It is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP, the first lens E1, the second lens E2, and the third lens E3 again to reach the partial reflective element BS. After that, the light beam is reflected again at the partial reflective element BS and sequentially passes through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP to exit towards the first side.

[0097] In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP can be attached to the first side of the first lens E1. Specifically, the second side of the quarter-wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter-wave plate QWP. The partially reflective element BS can be a semi-transparent and semi-reflective film layer deposited on the second side of the third lens E3.

[0098] Table 3 shows the basic parameters of the optical system in Example 4, where the units for radius of curvature and thickness are millimeters (mm). In this example, the second side surface S5 of the first optical lens E1, the first side surface S6 and the second side surface S7 of the second lens E2, and the first side surface S8 and the second side surface S9 of the third lens E3 are all aspherical surfaces. Table 4 shows the higher-order coefficients A4, A6, A8, and A9 that can be used for each aspherical mirror surface S5-S9 in Example 4. 10 A 12 A 14A 16 A 18 and A 20 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0099] surface element Surface type radius of curvature thickness Refractive index Abbe number Refraction / Reflection S0 spherical endless -1290.0000 refraction S1 Stabilizer (STO) spherical endless 15.0000 refraction S2 Reflective polarizing element (RP) spherical endless 0.1000 1.497 57.59 refraction S3 Quarter-wave plate (QWP) spherical endless 0.1000 1.497 57.59 refraction S4 First lens (E1) spherical endless 5.0358 1.497 57.59 refraction S5 aspherical -107.3018 0.7610 refraction S6 Second lens (E2) aspherical -165.6273 4.2617 1.546 55.99 refraction S7 aspherical -110.6135 0.9733 refraction S8 Third lens (E3) aspherical -1467.9535 3.8395 1.546 55.99 refraction S9 Partial reflective element (BS) aspherical -90.7947 -3.8395 1.546 55.99 reflection S10 aspherical -1467.9535 -0.9733 refraction S11 aspherical -110.6135 -4.2617 refraction S12 aspherical -165.6273 -0.7610 refraction S13 aspherical -107.3018 -5.0358 1.497 57.59 refraction S14 Quarter-wave plate (QWP) spherical endless -0.1000 1.497 57.59 refraction S15 Reflective polarizing element (RP) spherical endless 0.1000 1.497 57.59 reflection S16 First lens (E1) spherical endless 5.0358 1.497 57.59 refraction S17 aspherical -107.3018 0.7610 refraction S18 Second lens (E2) aspherical -165.6273 4.2617 1.546 55.99 refraction S19 aspherical -110.6135 0.9733 refraction S20 Third lens (E3) aspherical -1467.9535 3.8395 1.546 55.99 refraction S21 aspherical -90.7947 0.9418 refraction S22 Image View (IMG) spherical endless 0.0000 refraction

[0100] Table 3

[0101]

[0102]

[0103] Table 4

[0104] Example 5

[0105] The optical system according to Embodiment 5 of this application has the same structure as the optical system described in Embodiment 4, and sequentially includes, from the first side to the second side along the optical axis: a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, a third lens E3, and a partially reflective element BS. The first lens E1 has positive optical power, with its first side being planar and its second side being convex. The second lens E2 has positive optical power, with its first side being concave and its second side being convex. The third lens E3 has positive optical power, with its first side being concave and its second side being convex. The second side of the quarter-wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter-wave plate QWP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the second side of the third lens E3. A light beam emitted from the image plane IMG located on the second side passes sequentially through the partial reflective element BS, the third lens E3, the second lens E2, the first lens E1, and the quarter-wave plate QWP to reach the reflective polarizing element RP. At the reflective polarizing element RP, the beam is reflected again and passes through the quarter-wave plate QWP, the first lens E1, the second lens E2, and the third lens E3 to reach the partial reflective element BS. Then, the beam is reflected again at the partial reflective element BS and passes sequentially through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as Table 3 in Embodiment 4, and the table of higher-order coefficients of the aspherical mirror is the same as Table 4 in Embodiment 4.

[0106] The difference between this embodiment and embodiment 4 lies in the values ​​of the effective half-apertures T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1, and the values ​​of the effective half-apertures T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment and embodiment 4 are shown in Table 7 below.

[0107] Example 6

[0108] The optical system according to Embodiment 6 of this application has the same structure as the optical system described in Embodiment 4, and sequentially includes, from the first side to the second side along the optical axis: a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, a third lens E3, and a partially reflective element BS. The first lens E1 has positive optical power, with its first side being planar and its second side being convex. The second lens E2 has positive optical power, with its first side being concave and its second side being convex. The third lens E3 has positive optical power, with its first side being concave and its second side being convex. The second side of the quarter-wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter-wave plate QWP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the second side of the third lens E3. A light beam emitted from the image plane IMG located on the second side passes sequentially through the partial reflector BS, the third lens E3, the second lens E2, the first lens E1, and the quarter-wave plate QWP to reach the reflective polarizer RP. At the reflective polarizer RP, the beam is reflected and passes again through the quarter-wave plate QWP, the first lens E1, the second lens E2, and the third lens E3 to reach the partial reflector BS. Then, the beam is reflected again at the partial reflector BS and passes sequentially through the third lens E3, the second lens E2, the first lens E1, the quarter-wave plate QWP, and the reflective polarizer RP before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as Table 3 in Embodiment 4, and the table of higher-order coefficients of the aspherical mirror is also the same as Table 4 in Embodiment 4.

[0109] The difference between this embodiment and Embodiment 4 lies in the different values ​​of the effective half-apertures T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1, and the different values ​​of the effective half-apertures T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment are also shown in Table 7 below.

[0110] Figure 6 The on-axis chromatic aberration curves of the optical systems of Embodiments 4, 5 and 6 are shown, which represent the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 7 Astigmatism curves of the optical systems of Examples 4, 5, and 6 are shown, representing meridional and sagittal image plane curvature. Figure 8 The distortion curves of the optical systems of Examples 4, 5, and 6 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 6 to 8 It can be seen that the optical systems given in Examples 4, 5 and 6 can achieve good imaging quality.

[0111] Example 7

[0112] The following is for reference Figures 9 to 12 The optical system according to Embodiment 7 of this application is described. Figure 9 A schematic diagram of the structure of an optical system according to Embodiment 7 of this application is shown.

[0113] like Figure 9 As shown, the optical system includes, in sequence from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflective element BS, and a third lens E3.

[0114] In this embodiment, the first lens E1 has positive optical power, with a first convex surface and a second flat surface. The second lens E2 has positive optical power, with both its first and second sides being convex. The third lens E3 has positive optical power, with its first concave surface and second convex surface.

[0115] In this embodiment, the light beam emitted from the image plane IMG located on the second side can pass sequentially through the third lens E3, the partial reflective element BS, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizing element RP. It is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP and the second lens E2 again to reach the partial reflective element BS. After that, the light beam is reflected again at the partial reflective element BS and passes sequentially through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit toward the first side.

[0116] In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP can be attached to the second side of the first lens E1. Specifically, the first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the first side of the third lens E3.

[0117] Table 5 shows the basic parameters of the optical system in Example 7, where the units for radius of curvature and thickness are millimeters (mm). In this example, the first side surface S2 of the first lens E1, the first side surface S6 and the second side surface S7 of the second lens E2, and the first side surface S16 and the second side surface S17 of the third lens E3 are all aspherical surfaces. Table 6 shows the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical mirror surfaces S2, S6-S7, and S16-S17 in Example 7. 10 A 12 A 14 A 16 A 18 and A 20 Each aspherical surface shape can be defined by formula (1) given in Example 1 above.

[0118]

[0119]

[0120] Table 5

[0121] coefficient\surface S2 S6 S7 S16 S17 A4 7.2366E-06 6.0313E-07 9.2076E-06 -7.1202E-07 3.0692E-06 A6 -5.2882E-09 -3.5877E-09 -2.5261E-09 3.0802E-09 -2.0769E-08 A8 -7.8065E-12 -9.0413E-12 1.0453E-11 -4.9956E-12 -4.2219E-11 A10 0.0000E+00 0.0000E+00 -1.4568E-14 0.0000E+00 1.2862E-13 A12 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A14 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A16 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A18 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 A20 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0122] Table 6

[0123] Example 8

[0124] The optical system according to Embodiment 8 of this application has the same structure as the optical system described in Embodiment 7, and sequentially includes, from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflective element BS, and a third lens E3. The first lens E1 has positive optical power, with a convex first side and a flat second side. The second lens E2 has positive optical power, with both its first and second sides being convex. The third lens E3 has positive optical power, with a concave first side and a convex second side. The first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partial reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the first side of the third lens E3. The light beam emitted from the image plane IMG located on the second side passes sequentially through the third lens E3, the partial reflector BS, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizer RP. It is reflected at the reflective polarizer RP and passes again through the quarter-wave plate QWP and the second lens E2 to reach the partial reflector BS. Then, the light beam is reflected again at the partial reflector BS and passes sequentially through the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, and the first lens E1 before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as Table 5 in Embodiment 7, and the table of higher-order coefficients of the aspherical mirror is the same as Table 6 in Embodiment 7.

[0125] The difference between this embodiment and Embodiment 7 lies in the values ​​of the effective half-apertures T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1, and the values ​​of the effective half-apertures T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment and Embodiment 7 are shown in Table 7 below.

[0126] Example 9

[0127] The optical system according to Embodiment 9 of this application has the same structure as the optical system described in Embodiment 7, and sequentially includes, from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partially reflective element BS, and a third lens E3. The first lens E1 has positive optical power, with a convex first side and a flat second side. The second lens E2 has positive optical power, with a convex first side and a convex second side. The third lens E3 has positive optical power, with a concave first side and a convex second side. The first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS can be a semi-transparent, semi-reflective film layer deposited on the first side of the third lens E3. The light beam emitted from the image plane IMG located on the second side passes sequentially through the third lens E3, the partial reflector BS, the second lens E2, and the quarter-wave plate QWP to reach the reflective polarizer RP. It is reflected at the reflective polarizer RP and passes again through the quarter-wave plate QWP and the second lens E2 to reach the partial reflector BS. Then, the light beam is reflected again at the partial reflector BS and passes sequentially through the second lens E2, the quarter-wave plate QWP, the reflective polarizer RP, and the first lens E1 before exiting towards the first side. The basic parameter table of the optical system in this embodiment is the same as Table 5 in Embodiment 7, and the table of higher-order coefficients of the aspherical mirror is also the same as Table 6 in Embodiment 7.

[0128] The difference between this embodiment and Embodiment 7 is that the effective half-aperture values ​​T1a1, T1b1, T1c1, and T1d1 of the first side surface of the first lens E1 in the directions a1, b1, c1, and d1 are different, as are the effective half-aperture values ​​T1a2, T1b2, T1c2, and T1d2 of the second side surface of the first lens in the directions a2, b2, c2, and d2. The values ​​of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, and T1d2 in this embodiment are also shown in Table 7 below.

[0129] Figure 10 The on-axis chromatic aberration curves of the optical systems of Embodiments 7, 8 and 9 are shown, which represent the deviation of light of different wavelengths from the convergence focal point after passing through the lens. Figure 11 Astigmatism curves of the optical systems of Embodiments 7, 8, and 9 are shown, representing meridional and sagittal image plane curvature. Figure 12 The distortion curves of the optical systems of Examples 7, 8, and 9 are shown, representing the distortion magnitude values ​​corresponding to different field of view angles. According to... Figures 10 to 12 It can be seen that the optical systems given in Examples 7, 8 and 9 can achieve good imaging quality.

[0130] In Examples 1 to 9, the combined focal length fz of the first lens, the reflective polarizing element, and the quarter-wave plate; the effective focal length f1 of the first lens; the effective focal length f2 of the second lens; the effective focal length f3 of the third lens; the effective focal length f of the optical system; the entrance pupil diameter EPD of the optical system; the distance TD between the first side surface of the first lens and the second side surface of the third lens on the optical axis; the center thickness CTR of the reflective polarizing element on the optical axis; the center thickness CTQ of the quarter-wave plate on the optical axis; the maximum semi-field of view (Semi-FOV) of the optical system; the effective half-aperture T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective radial profile of the first side surface of the first lens; and the effective half-aperture T1b1 from the optical center of the first side surface of the first lens to the left edge of the effective radial profile of the first side surface of the first lens. The effective half-aperture T1c1 from the optical center of the first side of the first lens to the lower edge of the effective radial profile of the first side of the first lens, the effective half-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective radial profile of the first side of the first lens, the effective half-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens, and the effective half-aperture T1d2 from the optical center of the second side of the first lens to the right edge of the effective radial profile of the second side of the first lens are shown in Table 7.

[0131]

[0132]

[0133] Table 7

[0134] Examples 1 to 9 respectively satisfy the conditions shown in Table 8.

[0135] Conditional / Example 1 2 3 4 5 6 7 8 9 f / fz 0.15 0.15 0.15 0.11 0.11 0.11 0.05 0.05 0.05 (T1a1+T1c1) / f 1.82 1.68 1.94 1.75 1.89 2.02 2.04 1.91 1.76 T1b1 / CT1 3.08 2.80 3.02 4.19 4.62 4.53 3.68 3.75 3.40 f1 / (T1a2+T1b2+T1c2+T1d2) 1.72 1.88 1.68 2.62 2.40 2.35 5.40 5.51 6.02 (CT2+CT3) / (CT1+CTR+CTQ) 1.20 1.20 1.20 1.55 1.55 1.55 1.98 1.98 1.98 T1a1 / EPD 3.73 3.13 4.05 3.26 3.89 4.22 4.22 3.89 3.26 (T1b1+T1d1) / TD 2.41 2.19 2.36 2.84 3.13 3.07 2.21 2.25 2.05 N1×(T1a1 / T1d1) 1.25 1.16 1.39 1.16 1.25 1.39 1.39 1.25 1.16 (T1a2+T1c2) / (f×tan(Semi-FOV)) 1.68 1.55 1.79 1.57 1.70 1.82 1.96 1.84 1.70 f3 / (R5+R6) -0.80 -0.80 -0.80 -0.11 -0.11 -0.11 -4.75 -4.75 -4.75 R4 / f2 -1.05 -1.05 -1.05 -0.19 -0.19 -0.19 -0.65 -0.65 -0.65 (NRP / NQWP)×T1b2(mm) 20.65 18.73 20.22 21.12 23.28 22.80 19.76 20.17 18.30

[0136] Table 8

[0137] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An optical system, characterized in that, It sequentially includes, from the first side to the second side along the optical axis: A first lens with positive optical power; A second lens with positive optical power, whose second side is convex; and A third lens with positive optical power, whose first side is concave and second side is convex; The optical system further includes: a reflective polarizing element and a quarter-wave plate, and the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens; The optical system further includes: a partial reflection element, and the partial reflection element is disposed on the first side or the second side of the third lens; The optical system satisfies: 0.04 < f / fz < 0.16, and 1.68 ≤ (T1a1 + T1c1) / f ≤ 2.04, where f is the effective focal length of the optical system, fz is the combined focal length of the first lens, the reflective polarizing element and the quarter-wave plate, T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, and T1c1 is the effective semi-aperture from the optical center of the first side of the first lens to the lower edge of the effective diameter profile of the first side of the first lens; The first side is the human eye side, and the second side is the display side; The number of lenses with optical power in the optical system is three.

2. The optical system according to claim 1, characterized in that, The effective semi-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective diameter profile of the first side of the first lens and the central thickness CT1 of the first lens on the optical axis satisfy: 2.80 ≤ T1b1 / CT1 ≤ 4.

62.

3. The optical system according to claim 1, characterized in that, The effective focal length f1 of the first lens, the effective semi-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, the effective semi-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective diameter profile of the second side of the first lens, the effective semi-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, and the effective semi-aperture T1d2 from the optical center of the second side of the first lens to the right edge of the effective diameter profile of the second side of the first lens satisfy: 1.68 ≤ f1 / (T1a2 + T1b2 + T1c2 + T1d2) ≤ 6.

02.

4. The optical system according to claim 1, characterized in that, The central thickness CT2 of the second lens on the optical axis, the central thickness CT3 of the third lens on the optical axis, the central thickness CT1 of the first lens on the optical axis, the central thickness CTR of the reflective polarizing element on the optical axis, and the central thickness CTQ of the quarter-wave plate on the optical axis satisfy: 1.20 ≤ (CT2 + CT3) / (CT1 + CTR + CTQ) < 2.

0.

5. The optical system according to claim 1, characterized in that, The entrance pupil diameter EPD of the optical system satisfies: 3.1 < T1a1 / EPD ≤ 4.

22.

6. The optical system according to claim 1, characterized in that, The effective semi-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective diameter profile of the first side of the first lens, the effective semi-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens, and the distance TD on the optical axis from the first side of the first lens to the second side of the third lens satisfy: 2.05 ≤ (T1b1 + T1d1) / TD ≤ 3.

13.

7. The optical system according to claim 1, characterized in that, The refractive index N1 of the first lens and the effective semi-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens satisfy: 1.16 ≤ N1×(T1a1 / T1d1) < 1.

4.

8. The optical system according to claim 1, characterized in that, The effective semi-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, the effective semi-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, and the maximum semi-field angle Semi-FOV of the optical system satisfy: 1.55 ≤ (T1a2 + T1c2) / (f×tan(Semi-FOV)) < 2.

0.

9. The optical system according to claim 1, characterized in that, The effective focal length f3 of the third lens, the radius of curvature R5 of the first side of the third lens, and the radius of curvature R6 of the second side of the third lens satisfy: -4.75 ≤ f3 / (R5 + R6) < -0.

1.

10. The optical system according to claim 1, characterized in that, The radius of curvature R4 of the second side of the second lens and the effective focal length f2 of the second lens satisfy: -1.05 ≤ R4 / f2 ≤ -0.

19.

11. The optical system according to claim 1, characterized in that, The refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective semi-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective diameter profile of the second side of the first lens satisfy: 18.30 mm ≤ (NR / NQ)×T1b2 < 23.3 mm.

12. An optical system, characterized in that, In sequence from the first side to the second side along the optical axis, it includes: A first lens with positive optical power; A second lens with positive optical power, whose second side is convex; and A third lens with positive optical power, whose first side is concave and the second side is convex; The optical system further includes: a reflective polarizing element and a quarter-wave plate, and the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens; The optical system further includes: a partial reflection element, and the partial reflection element is disposed on the first side or the second side of the third lens; The optical system satisfies: 0.04 < f / fz < 0.16, and 3.1 < T1a1 / EPD ≤ 4.22, where f is the effective focal length of the optical system, fz is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, T1a1 is the effective semi-aperture from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, and EPD is the entrance pupil diameter of the optical system; The first side is the human eye side, and the second side is the display side; The optical system has three lenses with optical power.

13. The optical system according to claim 12, characterized in that, The effective half-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective diameter profile of the first side of the first lens satisfies the following with respect to the center thickness CT1 of the first lens on the optical axis: 2.80≤T1b1 / CT1≤4.

62.

14. The optical system according to claim 12, characterized in that, The effective focal length f1 of the first lens, the effective half-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1b2 from the optical center of the second side of the first lens to the left edge of the effective radial profile of the second side of the first lens, the effective half-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens, and the effective half-aperture T1d2 from the optical center of the second side of the first lens to the right edge of the effective radial profile of the second side of the first lens satisfy the following: 1.68≤f1 / (T1a2+T1b2+T1c2+T1d2)≤6.

02.

15. The optical system according to claim 12, characterized in that, The center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the center thickness CT1 of the first lens on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis satisfy the following: 1.20≤(CT2+CT3) / (CT1+CTR+CTQ)<2.

0.

16. The optical system according to claim 13, characterized in that, The effective half-aperture T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens satisfies: 1.68≤(T1a1+T1c1) / f≤2.

04.

17. The optical system according to claim 12, characterized in that, The effective half-aperture T1b1 from the optical center of the first side of the first lens to the left edge of the effective radial profile of the first side of the first lens, the effective half-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective radial profile of the first side of the first lens, and the distance TD from the first side of the first lens to the second side of the third lens on the optical axis satisfy the following: 2.05≤(T1b1+T1d1) / TD≤3.

13.

18. The optical system according to claim 12, characterized in that, The refractive index N1 of the first lens and the effective half-aperture T1d1 from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens satisfy the following: 1.16≤N1×(T1a1 / T1d1)<1.

4.

19. The optical system according to claim 12, characterized in that, The effective half-aperture T1a2 from the optical center of the second side of the first lens to the upper edge of the effective radial profile of the second side of the first lens, and the effective half-aperture T1c2 from the optical center of the second side of the first lens to the lower edge of the effective radial profile of the second side of the first lens, satisfy the following conditions with the maximum semi-field of view (Semi-FOV) of the optical system: 1.55≤(T1a2+T1c2) / (f×tan(Semi-FOV))<2.

0.

20. The optical system according to claim 12, characterized in that, The effective focal length f3 of the third lens, the radius of curvature R5 of the first side surface of the third lens, and the radius of curvature R6 of the second side surface of the third lens satisfy the following: -4.75≤f3 / (R5+R6)<-0.

1.

21. The optical system according to claim 12, characterized in that, The radius of curvature R4 of the second side surface of the second lens and the effective focal length f2 of the second lens satisfy the following: -1.05≤R4 / f2≤-0.

19.

22. The optical system according to claim 12, characterized in that, The refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective half-aperture T1b2 of the effective diameter profile from the optical center of the second side of the first lens to the left edge of the second side of the first lens satisfy the following: 18.30mm≤(NR / NQ)×T1b2<23.3mm.

23. A VR device comprising the optical system as claimed in any one of claims 1 to 22.

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