CN117784408A

CN117784408A - Optical system and VR device including the same

Info

Publication number: CN117784408A
Application number: CN202311852980.3A
Authority: CN
Inventors: 张步康; 游金兴; 张晓彬; 金银芳; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-03-29

Abstract

The application discloses an optical system and VR device including the optical system. The optical system sequentially comprises from a first side to a second side along the optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having positive optical power, the first side of which is concave and the second side of which 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 effective focal length f of the optical system and the effective focal length f3 of the third lens meet 0.02< f/f3<0.15; the effective half-caliber T3a2 from the optical center of the second side surface of the third lens to the upper edge of the effective diameter profile of the second side surface of the third lens, the effective half-caliber T3c2 from the optical center of the second side surface of the third lens to the lower edge of the effective diameter profile of the second side surface of the third lens and the effective focal length f of the optical system meet 1.7< (T3a2+T3c2)/f <2.3.

Description

Optical system and VR device including the same

Technical Field

The present application relates to the field of optical elements, and more particularly, to an optical system and VR device including the same.

Background

Virtual Reality (VR) is a computer technology that enables users to experience an immersive sensation by simulating a three-dimensional environment. In recent years, VR technology has rapidly evolved from the original aspherical or fresnel lens to the now mainstream refractive lens. Initially, the solution of VR devices was limited by the optical system, which is generally bulky, and when used by a user, the center of gravity was forward, and experience was poor.

For the above reasons, a foldback scheme is proposed. The foldback scheme is a mode of repeatedly foldback light by applying a polarized light principle, thereby realizing a small and light thin VR device. However, the present foldback scheme mainly uses two lenses, and there is a general problem that the angle of view is small, and in addition, the image is easy to be distorted due to the birefringence phenomenon of light; meanwhile, the film pasting process in the foldback scheme is high in difficulty and low in yield, and the product cost is influenced; and the imaging quality of the system and the miniaturization and the light-weight degree of the system are required to be further improved.

Disclosure of Invention

The application provides an optical system, can include in order from first side to second side along the optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having 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 attached to the first side or the second side of the first lens; the optical system can satisfy: 0.02< f/f3<0.15, and 1.7< (t3a2+t3c2)/f <2.3, where f is an effective focal length of the optical system, f3 is an effective focal length of the third lens, T3a2 is an effective half-caliber from an optical center of the second side of the third lens to an upper edge of an effective diameter profile of the second side of the third lens, and T3c2 is an effective half-caliber from an optical center of the second side of the third lens to a lower edge of an effective diameter profile of the second side of the third lens.

In one embodiment, the radius of curvature R6 of the second side of the third lens, the radius of curvature R5 of the first side of the third lens, the effective half-caliber T3b2 from the optical center of the second side of the third lens to the left edge of the effective diameter profile of the second side of the third lens, and the effective half-caliber T3b1 from the optical center of the first side of the third lens to the left edge of the effective diameter profile of the first side of the third lens may satisfy: 0.05< (R6/R5) × (T3 b2/T3b 1) <0.85.

In one embodiment, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens may satisfy: 0.2< f 3/(f1+f2) <1.4.

In one embodiment, the effective half-caliber T3a1 from the optical center of the first side of the third lens to the upper edge of the effective diameter profile of the first side of the third lens and the effective half-caliber T2a2 from the optical center of the second side of the second lens to the upper edge of the effective diameter profile of the second side of the second lens may satisfy: 0.9< T3a1/T2a2<1.2.

In one embodiment, the effective half-caliber T3d1 from the optical center of the first side of the third lens to the right edge of the effective diameter profile of the first side of the third lens and the effective half-caliber T2d1 from the optical center of the first side of the second lens to the right edge of the effective diameter profile of the first side of the second lens may satisfy: 0.9< T3d1/T2d1<1.1.

In one embodiment, the distance TD between the optical center of the second side of the third lens and the right edge of the effective radius profile of the second side of the third lens and the distance TD between the first side of the first lens and the second side of the third lens on the optical axis may be as follows: 1.0< T3d2/TD <1.8.

In one embodiment, the maximum half field angle Semi-FOV of the optical system may satisfy: 1.0< (f×tan (Semi-FOV))/T3 a2<1.5.

In one embodiment, the radius of curvature R5 of the effective half-caliber T3c1 from the optical center of the first side surface of the third lens to the lower edge of the effective diameter profile of the first side surface of the third lens and the first side surface of the third lens may satisfy: -0.4< T3c1/R5<0.

In one embodiment, a center thickness CT3 of the third lens on the optical axis, an optical center of the first side of the third lens to an effective half-caliber T3b1 of the effective diameter profile left edge of the first side of the third lens, and an optical center of the second side of the third lens to an effective half-caliber T3b2 of the effective diameter profile left edge of the second side of the third lens may satisfy: 2.8mm < CT3× (T3 b1/T3b 2) <3.7mm.

In one embodiment, 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 may satisfy: 5.0mm < CT1× (CTR/CTQ) <6.6mm.

In one embodiment, the radius of curvature R6 of the second side of the third lens, the effective half-caliber T3b2 from the optical center of the second side of the third lens to the left edge of the effective diameter profile of the second side of the third lens, and the effective half-caliber T3d2 from the optical center of the second side of the third lens to the right edge of the effective diameter profile of the second side of the third lens may satisfy: -2.2< R6/(T3b2+T3d2) < -1.3.

In another aspect, the present application further provides an optical system, which may include, in order from a first side to a second side along an optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having 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 attached to the first side or the second side of the first lens; the optical system can satisfy: 0.02< f/f3<0.15, and 1.0< T3d2/TD <1.8, where f is an effective focal length of the optical system, f3 is an effective focal length of the third lens, T3d2 is an effective half-caliber from an optical center of the second side of the third lens to a right edge of an effective diameter profile of the second side of the third lens, and TD is a distance on the optical axis from the first side of the first lens to the second side of the third lens.

In one embodiment, the effective half-caliber T3a2 from the optical center of the second side of the third lens to the upper edge of the effective diameter profile of the second side of the third lens and the effective half-caliber T3c2 from the optical center of the second side of the third lens to the lower edge of the effective diameter profile of the second side of the third lens may satisfy: 1.7< (T3a2+T3c2)/f <2.3.

In yet another aspect, the present application further provides a VR device, where the VR device includes an optical system provided in any one of the foregoing embodiments, and the first side is a human eye side and the second side is a display side.

The optical system comprises a first lens with positive focal power, a second lens with positive focal power and a third lens with positive focal power sequentially from a first side to a second side along an optical axis, wherein the second side surface of the second lens is a convex surface, the first side surface of the third lens is a concave surface, the second side surface is a convex surface, and a reflective polarizing element and a quarter wave plate are attached to the first side or the second side of the first lens. The first lens, the second lens and the third lens in the optical system are all designed to have positive focal power, so that light convergence is facilitated; meanwhile, the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens, and the reflective polarizing element and the quarter-wave plate can be combined together, so that the reflective efficiency is improved. And, according to the optical system control optical system disclosed by the application, the effective focal length f of the optical system and the effective focal length f3 of the third lens meet 0.02< f/f3<0.15, under the precondition, the effective half calibers T3a2 and T3c2 from the second side optical center of the third lens to the upper edge and the lower edge of the effective diameter profile and the effective focal length f of the optical system meet 1.7< (T3a2+T3c2)/f <2.3, the edge profile shape and thickness of the third lens can be reasonably controlled, the forming of the third lens is facilitated, the angle of light on a screen is also facilitated to be reduced, and the brightness uniformity of VR equipment is ensured.

Drawings

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

fig. 1 shows a schematic configuration diagram of an optical system according to embodiment 1, embodiment 2, and embodiment 3 of the present application;

fig. 2, 3 and 4 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 1, example 2 and example 3, respectively;

fig. 5 shows a schematic structural view of an optical system according to embodiment 4, embodiment 5, and embodiment 6 of the present application;

fig. 6, 7 and 8 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 4, example 5 and example 6, respectively;

fig. 9 shows a schematic structural view of an optical system according to embodiment 7, embodiment 8, and embodiment 9 of the present application;

fig. 10, 11 and 12 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 7, example 8 and example 9, respectively;

FIG. 13 shows a schematic view of the effective half-aperture in the a1, b1, c1, d1 direction of the first side of the second lens or third lens in an optical system according to an exemplary embodiment of the present application; and

Fig. 14 shows a schematic view of an effective half-aperture in a2, b2, c2, d2 direction of a second side of a second lens or a third lens in an optical system according to an exemplary embodiment of the present application.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of exemplary embodiments of the application and are not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification, the expressions first, second, etc. are only used to distinguish one feature from another feature, and do not represent any limitation of the feature. Accordingly, a first optical lens discussed below may also be referred to as a second optical lens, and a second optical lens may also be referred to as a first optical lens, without departing from the teachings of the present application.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the present application, use of "may" means "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The features, principles, and other aspects of the present application are described in detail below.

The optical system according to the exemplary embodiment of the present application may include a first lens, a second lens, and a third lens sequentially arranged from a first side to a second side along the optical axis, 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.

In an exemplary embodiment, the second side of the second lens may be convex. The first side of the third lens may be concave and the second side may be convex.

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 the first side or the second side of the first lens.

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

An optical system will be exemplarily described below with reference to fig. 1. As shown in fig. 1, the optical system according to the exemplary embodiment of the present 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, which are sequentially arranged 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 actual use, the optical system according to the exemplary embodiment of the present application may be used as a VR lens, in which case 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 on a second side (e.g., display side). The light beam emitted from the image plane IMG may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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 toward the first side (e.g., the human eye side). In an exemplary embodiment, the partially reflective element BS may be a semi-transparent and semi-reflective film layer plated on the second side or the first side of the third lens E3.

In an exemplary embodiment, the effective half-caliber of the first side of the second lens or the third lens in the a1, b1, c1, d1 direction is as shown in fig. 13, specifically, the effective half-caliber from the optical center of the first side of the second lens to the upper edge of the effective diameter profile of the first side of the second lens is T2a1; the effective half caliber from the optical center of the first side surface of the second lens to the left edge of the effective diameter outline of the first side surface of the second lens is T2b1; the effective half caliber from the optical center of the first side surface of the second lens to the lower edge of the effective diameter outline of the first side surface of the second lens is T2c1; the effective half-caliber from the optical center of the first side surface of the second lens to the right edge of the effective diameter profile of the first side surface of the second lens is T2d1. The effective half caliber from the optical center of the first side surface of the third lens to the upper edge of the effective diameter outline of the first side surface of the third lens is T3a1; the effective half caliber from the optical center of the first side surface of the third lens to the left edge of the effective diameter outline of the first side surface of the third lens is T3b1; the effective half caliber from the optical center of the first side surface of the third lens to the lower edge of the effective diameter outline of the first side surface of the third lens is T3c1; the effective half-caliber from the optical center of the first side surface of the third lens to the right edge of the effective diameter profile of the first side surface of the third lens is T3d1.

In an exemplary embodiment, the effective half-caliber of the second side of the second lens or the third lens in the a2, b2, c2, d2 direction is as shown in fig. 14, specifically, the effective half-caliber from the optical center of the second side of the second lens to the upper edge of the effective diameter profile of the second side of the second lens is T2a2; the effective half caliber from the optical center of the second side surface of the second lens to the left edge of the effective diameter outline of the second side surface of the second lens is T2b2; the effective half caliber from the optical center of the second side surface of the second lens to the lower edge of the effective diameter outline of the second side surface of the second lens is T2c2; the effective half-caliber from the optical center of the second side surface of the second lens to the right edge of the effective diameter profile of the second side surface of the second lens is T2d2. The effective half caliber from the optical center of the second side surface of the third lens to the upper edge of the effective diameter outline of the second side surface of the third lens is T3a2; the effective half caliber from the optical center of the second side surface of the third lens to the left edge of the effective diameter outline of the second side surface of the third lens is T3b2; the effective half caliber from the optical center of the second side surface of the third lens to the lower edge of the effective diameter outline of the second side surface of the third lens is T3c2; the effective half-caliber from the optical center of the second side surface of the third lens to the right edge of the effective diameter profile of the second side surface of the third lens is T3d2.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.02< f/f3<0.15, where f is an effective focal length of the optical system and f3 is an effective focal length of the third lens.

In an exemplary embodiment, the optical system of the present application may satisfy the condition of 1.7< (t3a2+t3c2)/f <2.3, where T3a2 is an effective half-caliber from an optical center of the second side surface of the third lens to an upper edge of an effective diameter profile of the second side surface of the third lens, T3c2 is an effective half-caliber from an optical center of the second side surface of the third lens to a lower edge of an effective diameter profile of the second side surface of the third lens, and f is an effective focal length of the optical system.

According to the optical system of the exemplary embodiment of the present application, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is a convex surface, the first side of the third lens is a concave surface, the second side is a convex surface, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The first lens, the second lens and the third lens in the optical system are all designed to have positive focal power, so that light convergence is facilitated; meanwhile, the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens, and the reflective polarizing element and the quarter-wave plate are combined together, so that the reflective efficiency is improved. In addition, the optical system according to the exemplary embodiment of the application can reasonably control the shape and thickness of the edge profile of the third lens by controlling the effective focal length f of the optical system and the effective focal length f3 of the third lens to be 0.02< f/f3<0.15 and simultaneously controlling the effective half calibers T3a2 and T3c2 from the second side optical center of the third lens to the upper edge and the lower edge of the effective diameter profile and the effective focal length f of the optical system to be 1.7< (T3a2+T3c2)/f <2.3, thereby being beneficial to forming the third lens and reducing the angle of light on a screen, and further guaranteeing the brightness uniformity of VR equipment.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.05< (R6/R5) × (T3 b2/T3b 1) <0.85, wherein R6 is a radius of curvature of the second side surface of the third lens, R5 is a radius of curvature of the first side surface of the third lens, T3b2 is an effective half-caliber from an optical center of the second side surface of the third lens to a left edge of an effective diameter profile of the second side surface of the third lens, and T3b1 is an effective half-caliber from an optical center of the first side surface of the third lens to a left edge of an effective diameter profile of the first side surface of the third lens. The central thickness of the third lens can be reasonably restrained by controlling the optical system to meet the condition of 0.05< (R6/R5) × (T3 b2/T3b 1) <0.85, so that the forming of the third lens is facilitated, the trimming effect of the third lens is also facilitated, the shape of the light-emitting screen light path is controlled, the miniaturization of VR equipment is facilitated, and the comfort of a user is improved.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.2< f 3/(f1+f2) <1.4, where f3 is an effective focal length of the third lens, f1 is an effective focal length of the first lens, and f2 is an effective focal length of the second lens. The ratio of the effective focal length of the third lens to the sum of the effective focal lengths of the first lens and the second lens is controlled within the range, so that the view angle of the system is restrained, and the system can meet the characteristic of large view field of the VR lens.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.9< T3a1/T2a2<1.2, where T3a1 is an effective half-caliber from an optical center of the first side of the third lens to an effective diameter profile upper edge of the first side of the third lens, and T2a2 is an effective half-caliber from an optical center of the second side of the second lens to an effective diameter profile upper edge of the second side of the second lens. The ratio of the effective half caliber from the optical center of the first side surface of the third lens to the upper edge of the effective diameter profile to the effective half caliber from the optical center of the second side surface of the second lens to the upper edge of the effective diameter profile is controlled within the range, so that the upper edges of the third lens and the second lens have consistent shapes, the volume of the second lens is reduced, and the weight of VR equipment is reduced.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.9< T3d1/T2d1<1.1, where T3d1 is an effective half-caliber from an optical center of the first side of the third lens to an effective diameter profile right edge of the first side of the third lens, and T2d1 is an effective half-caliber from an optical center of the first side of the second lens to an effective diameter profile right edge of the first side of the second lens. The ratio of the effective half caliber from the first side optical center of the third lens to the right edge of the effective diameter profile to the effective half caliber from the first side optical center of the second lens to the right edge of the effective diameter profile is controlled within the range, so that the edge thicknesses of the third lens and the second lens are controlled, and the forming of the third lens and the second lens is facilitated.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 1.0< T3d2/TD <1.8, where T3d2 is an effective half-caliber from an optical center of the second side surface of the third lens to a right edge of an effective diameter profile of the second side surface of the third lens, and TD is a distance on an optical axis from the first side surface of the first lens to the second side surface of the third lens. The ratio of the effective half caliber from the optical center of the second side surface of the third lens to the right edge of the effective diameter profile to the distance from the first side surface of the first lens to the second side surface of the third lens on the optical axis is controlled in the range, so that the effective focal length of the system is at a reasonable level, the VR equipment can be thinner, and the miniaturization of the VR equipment is facilitated.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 1.0< (f×tan (Semi-FOV))/T3 a2<1.5, where f is an effective focal length of the optical system, semi-FOV is a maximum half field angle of the optical system, and T3a2 is an effective half caliber from an optical center of the second side of the third lens to an upper edge of an effective diameter profile of the second side of the third lens. The optical system is controlled to meet the condition that (f multiplied by tan (Semi-FOV))/T3 a2 is less than 1.5, so that on one hand, the relation between the focal length and the angle of view is controlled, the size of a chip of the perspective optical system is restrained, the resolution of the chip is controlled, and finally, the experience of the interaction between a consumer and reality is improved; on the other hand, the contour shape of the second side surface of the third lens is controlled, so that the processing and forming of the third lens are facilitated.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression-0.4 < T3c1/R5<0, where T3c1 is an effective half-caliber from an optical center of the first side surface of the third lens to a lower edge of an effective diameter profile of the first side surface of the third lens, and R5 is a radius of curvature of the first side surface of the third lens. By controlling the ratio of the effective half-caliber of the optical center of the first side surface of the third lens to the lower edge of the effective diameter profile to the curvature radius of the first side surface of the third lens in the range, the distribution of the focal power of the third lens in the optical system is controlled, and the aberration of the system is corrected.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 2.8mm < ct3× (T3 b1/T3b 2) <3.7mm, where CT3 is the center thickness of the third lens on the optical axis, T3b1 is the effective half-caliber from the optical center of the first side of the third lens to the effective diameter profile left edge of the first side of the third lens, and T3b2 is the effective half-caliber from the optical center of the second side of the third lens to the effective diameter profile left edge of the second side of the third lens. By controlling the optical system to meet the condition of 2.8mm < CT3× (T3 b1/T3b 2) <3.7mm, the thickness limit and the left edge shape of the third lens are constrained, the processing of the third lens is facilitated from the aspect of molding, the slope angle (surface slope) of the third lens is constrained from the aspect of performance, and the ghost image risk is reduced.

In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 5.0mm < ct1× (CTR/CTQ) <6.6mm, where CT1 is the center thickness of the first lens on the optical axis, CTR is the center thickness of the reflective polarizing element on the optical axis, and CTQ is the center thickness of the quarter-wave plate on the optical axis. The optical system is controlled to meet the condition that CT1× (CTR/CTQ) is less than 6.6mm, so that the thickness of the center of the first lens is thicker, the film is attached, and the angle of view of the optical system is increased.

In an exemplary embodiment, the optical system of the present application may satisfy the condition-2.2 < R6/(t3b2+t3d2) < -1.3, where R6 is a radius of curvature of the second side of the third lens, T3b2 is an effective half caliber from an optical center of the second side of the third lens to a left edge of an effective diameter profile of the second side of the third lens, and T3d2 is an effective half caliber from an optical center of the second side of the third lens to a right edge of the effective diameter profile of the second side of the third lens. The ratio of the curvature radius of the second side surface of the third lens to the sum of the effective half calibers from the optical center of the second side surface of the third lens to the left and right edges of the effective diameter profile is controlled in the range, so that the thickness of the third lens and the shape of the left and right edges are controlled, the forming of the third lens and the control of the system field angle are facilitated, and the immersion feeling of a user is facilitated.

In an exemplary embodiment, the optical system of the present application may include at least one aperture. The diaphragm can restrict the light path and control the intensity of light. The aperture may be arranged in a suitable position of the optical system, for example the aperture may be located between the first side (e.g. the human eye side) and the first lens.

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

According to the optical system of the exemplary embodiment of the present application, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is a convex surface, the first side of the third lens is a concave surface, the second side is a convex surface, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The first lens, the second lens and the third lens in the optical system are all designed to have positive focal power, so that light convergence is facilitated; meanwhile, the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens, and the reflective polarizing element and the quarter-wave plate are combined together, so that the reflective efficiency is improved. Meanwhile, the effective focal length f of the optical system and the effective focal length f3 of the third lens are controlled to be 0.02< f/f3<0.15, under the precondition, the ratio of the sum of the effective half calibers T3a2 and T3c2 from the optical center of the second side surface of the third lens to the upper edge and the lower edge of the effective diameter profile to the effective focal length f of the optical system is controlled to be 1.7< (T3a2+T3c2)/f <2.3, the edge profile shape and thickness of the third lens can be reasonably controlled, the forming of the third lens is facilitated, the angle of light on a screen is also facilitated to be reduced, and therefore the brightness uniformity of VR equipment is ensured.

On the other hand, according to the optical system of the present exemplary embodiment, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is convex, the first side of the third lens is concave, the second side is convex, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The first lens, the second lens and the third lens in the optical system are all designed to have positive focal power, so that light convergence is facilitated; meanwhile, the reflective polarizing element and the quarter-wave plate are attached to the first side or the second side of the first lens, and the reflective polarizing element and the quarter-wave plate are combined together, so that the reflective efficiency is improved. Meanwhile, the effective focal length f of the optical system and the effective focal length f3 of the third lens are controlled to be 0.02< f/f3<0.15, and under the precondition, the effective semi-caliber T3d2 from the optical center of the second side surface of the third lens to the right edge of the effective diameter profile and the distance TD from the first side surface of the first lens to the second side surface of the third lens on the optical axis are controlled to be 1.0< T3d2/TD <1.8, so that the effective focal length of the system is at a reasonable level, VR equipment can be thinner, and miniaturization of the VR equipment is facilitated.

Specific examples of the optical system applicable to the above-described embodiments are further described below with reference to the drawings.

Example 1

An optical system according to embodiment 1 of the present application is described below with reference to fig. 1 to 4. Fig. 1 shows a schematic configuration of an optical system according to embodiment 1 of the present application.

As shown in fig. 1, the optical system sequentially includes, from a first side to a second side along an 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 reflecting element BS.

In this embodiment, the first lens E1 has positive power, and the first side surface thereof is convex and the second side surface thereof is planar. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex.

In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass 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 toward the first side.

In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP may 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 may be a semi-transparent film layer plated on the second side of the third lens E3.

Table 1 shows basic parameters of the optical system of example 1, in which the unit of radius of curvature and thickness are both millimeters (mm).

TABLE 1

In embodiment 1, the first side S2 of the first lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S8 and the second side S9 of the third lens E3 are all aspheric, and the surface shape x of the aspheric lens can be defined by, but not limited to, the following aspheric formula:

wherein x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c=1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the aspherical i-th order. Table 2 below shows the higher order coefficients A that can be used for the aspherical mirror surfaces S2, S6-S9 in example 1 ₄ 、A ₆ 、A ₈ 、A ₁₀ 、A ₁₂ 、A ₁₄ 、A ₁₆ 、A ₁₈ And A ₂₀ 。

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

TABLE 2

Example 2

The structure of the optical system according to embodiment 2 of the present application is the same as that of the optical system described in embodiment 1, and includes, in order 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 reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer 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 polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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 toward the first side. The basic parameter table of the optical system of this example is the same as table 1, and the higher order coefficient table of the aspherical mirror surface is the same as table 2.

This embodiment differs from embodiment 1 in that the values of the effective half apertures T2d1 of the first side surfaces of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surfaces of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surfaces of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surfaces of the third lens in the a2, b2, c2, d2 directions are different. Specifically, T2d1 is an effective half-caliber from an optical center of the first side of the second lens to a right edge of an effective diameter profile of the first side of the second lens; t2a2 is the effective half-caliber from the optical center of the second side of the second lens to the upper edge of the effective diameter profile of the second side of the second lens; t3a1 is the effective half-caliber from the optical center of the first side of the third lens to the upper edge of the effective diameter profile of the first side of the third lens; t3b1 is the effective half-caliber from the optical center of the first side of the third lens to the left edge of the effective diameter profile of the first side of the third lens; t3c1 is the effective half-caliber from the optical center of the first side of the third lens to the lower edge of the effective diameter profile of the first side of the third lens; t3d1 is the effective half-caliber from the optical center of the first side of the third lens to the right edge of the effective diameter profile of the first side of the third lens; t3a2 is the effective half-caliber from the optical center of the second side of the third lens to the upper edge of the effective diameter profile of the second side of the third lens; t3b2 is the effective half-caliber from the optical center of the second side of the third lens to the left edge of the effective diameter profile of the second side of the third lens; t3c2 is the effective half-caliber from the optical center of the second side of the third lens to the lower edge of the effective diameter profile of the second side of the third lens; and T3d2 is the effective half-caliber from the optical center of the second side of the third lens to the right edge of the effective diameter profile of the second side of the third lens. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example and example 1, respectively, are shown in table 7 below.

Example 3

The structure of the optical system according to embodiment 3 of the present application is also the same as that of the optical system described in embodiment 1, and includes, in order 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 reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer 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 polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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 toward the first side. The basic parameter table of the optical system of this example is also the same as table 1, and the higher order coefficient table of the aspherical mirror is also the same as table 2.

This embodiment is also different from embodiment 1 in that the values of the effective half apertures T2d1 of the first side surface of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surface of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surface of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surface of the third lens in the a2, b2, c2, d2 directions are different. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example are also shown in table 7 below.

Fig. 2 shows on-axis chromatic aberration curves of the optical systems of embodiment 1, embodiment 2, and embodiment 3, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 3 shows astigmatism curves of the optical systems of example 1, example 2, and example 3, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 4 shows distortion curves of the optical systems of example 1, example 2, and example 3, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 2 to 4, the optical systems given in embodiment 1, embodiment 2 and embodiment 3 can achieve good imaging quality.

Example 4

An optical system according to embodiment 4 of the present application is described below with reference to fig. 5 to 8. Fig. 5 shows a schematic structural diagram of an optical system according to embodiment 4 of the present application.

As shown in fig. 5, the optical system sequentially includes, from a first side to a 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 reflecting element BS.

In this embodiment, the first lens E1 has positive power, and the first side surface thereof is a plane and the second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex.

In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 again to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass 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 toward the first side.

In this embodiment, the reflective polarizing element RP and the quarter wave plate QWP may 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 may be a semi-transparent film layer plated on the second side of the third lens E3.

Table 3 shows basic parameters of the optical system of example 4, in which the unit of radius of curvature and thickness are both millimeters (mm). In this example, the second side S5 of the first optical lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S8 and the second side S9 of the third lens E3 are all aspherical, and Table 4 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S5 to S9 in example 4 ₄ 、A ₆ 、A ₈ 、A ₁₀ 、A ₁₂ 、A ₁₄ 、A ₁₆ 、A ₁₈ And A ₂₀ Wherein each aspherical surface profile can be defined by the formula (1) given in the above-described embodiment 1.

TABLE 3 Table 3

Coefficient/surface	S5	S6	S7	S8	S9
						A4	-9.3366E-07	8.0702E-07	-6.3265E-06	-4.7111E-06	-4.9338E-07
A6	8.7462E-10	4.0909E-09	-1.7551E-09	-5.3134E-10	3.2606E-10
						A8	-7.0427E-12	1.4193E-13	1.8243E-12	-5.2505E-12	-6.5003E-13
A10	-4.0004E-17	0.0000E+00	2.9923E-14	0.0000E+00	-1.0413E-15
						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

TABLE 4 Table 4

Example 5

The structure of the optical system according to embodiment 5 of the present application is the same as that of the optical system described in embodiment 4, and includes, in order 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 reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is a plane and a second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is 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 may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass 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 toward the first side. The basic parameter table of the optical system of this example is the same as table 3 in example 4, and the higher order coefficient table of the aspherical mirror surface is the same as table 4 in example 4.

This embodiment differs from embodiment 4 in that the values of the effective half apertures T2d1 of the first side surfaces of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surfaces of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surfaces of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surfaces of the third lens in the a2, b2, c2, d2 directions are different. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example and example 4, respectively, are shown in table 7 below.

Example 6

The structure of the optical system according to embodiment 6 of the present application is also the same as that of the optical system described in embodiment 4, and includes, in order 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 reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is a plane and a second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is 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 may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass 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 toward the first side. The basic parameter table of the optical system of this example is also the same as table 3 in example 4, and the higher order coefficient table of the aspherical mirror surface is also the same as table 4 in example 4.

This embodiment is also different from embodiment 4 in that the values of the effective half apertures T2d1 of the first side surface of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surface of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surface of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surface of the third lens in the a2, b2, c2, d2 directions are different. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example are also shown in table 7 below.

Fig. 6 shows on-axis chromatic aberration curves of the optical systems of examples 4, 5 and 6, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 7 shows astigmatism curves of the optical systems of example 4, example 5, and example 6, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 8 shows distortion curves of the optical systems of example 4, example 5, and example 6, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 6 to 8, the optical systems given in embodiment 4, embodiment 5 and embodiment 6 can achieve good imaging quality.

Example 7

An optical system according to embodiment 7 of the present application is described below with reference to fig. 9 to 12. Fig. 9 shows a schematic structural view of an optical system according to embodiment 7 of the present application.

As shown in fig. 9, the optical system sequentially includes, from a first side to a 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.

In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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.

In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP may 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 may be a semi-transparent film layer plated on the first side of the third lens E3.

Table 5 shows basic parameters of the optical system of example 7, in which the unit of radius of curvature and thickness are both millimeters (mm). In this embodiment, the first side S2 of the first lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S16 and the second side S of the third lens E3The side S17 is aspherical, and Table 6 shows the higher order coefficients A that can be used for aspherical mirror surfaces S2, S6-S7 and S16-S17 in example 7 ₄ 、A ₆ 、A ₈ 、A ₁₀ 、A ₁₂ 、A ₁₄ 、A ₁₆ 、A ₁₈ And A ₂₀ Wherein each aspherical surface profile can be defined by the formula (1) given in the above-described embodiment 1.

Surface of the body

Element

Surface type

Radius of curvature

Thickness of (L)

Refractive index

Abbe number

Refraction/reflection

S0

Spherical surface

Infinity is provided

-1161.0000

Refraction by refraction

S1

Diaphragm (STO)

Spherical surface

Infinity is provided

13.5000

Refraction by refraction

S2

First lens (E1)

Aspherical surface

213.4281

5.5829

1.497

57.59

Refraction by refraction

S3

Reflective polarizing element (RP)

Spherical surface

Infinity is provided

0.0900

1.497

57.59

Refraction by refraction

S4

Quarter Wave Plate (QWP)

Spherical surface

Infinity is provided

0.0900

1.497

57.59

Refraction by refraction

S5

Spherical surface

Infinity is provided

0.9017

Refraction by refraction

S6

Second lens (E2)

Aspherical surface

165.7512

8.5481

1.546

55.99

Refraction by refraction

S7

Aspherical surface

-35.7812

0.4971

Refraction by refraction

S8

Partial reflecting member (BS)

Aspherical surface

-77.1731

-0.4971

Reflection of

S9

Aspherical surface

-35.7812

-8.5481

Refraction by refraction

S10

Aspherical surface

165.7512

-0.9017

Refraction by refraction

S11

Quarter Wave Plate (QWP)

Spherical surface

Infinity is provided

-0.0900

1.497

57.59

Refraction by refraction

S12

Reflective polarizing element (RP)

Spherical surface

Infinity is provided

0.0900

1.497

57.59

Reflection of

S13

Spherical surface

Infinity is provided

0.9017

Refraction by refraction

S14

Second lens (E2)

Aspherical surface

165.7512

8.5481

1.546

55.99

Refraction by refraction

S15

Aspherical surface

-35.7812

0.4971

Refraction by refraction

S16

Third lens (E2)

Aspherical surface

-77.1731

2.8744

1.546

55.99

Refraction by refraction

S17

Aspherical surface

-64.6277

1.4136

Refraction by refraction

S18

Image plane (IMG)

Spherical surface

Infinity is provided

0.0000

Refraction by refraction

TABLE 5

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

TABLE 6

Example 8

The structure of the optical system according to embodiment 8 of the present application is the same as that of the optical system described in embodiment 7, and includes, in order 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, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer 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 polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the first side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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. The basic parameter table of the optical system of this example is the same as table 5 in example 7, and the higher order coefficient table of the aspherical mirror surface is the same as table 6 in example 7.

This embodiment differs from embodiment 7 in that the values of the effective half apertures T2d1 of the first side surfaces of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surfaces of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surfaces of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surfaces of the third lens in the a2, b2, c2, d2 directions are different. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example and example 7, respectively, are shown in table 7 below.

Example 9

The structure of the optical system according to embodiment 9 of the present application is also the same as that of the optical system described in embodiment 7, and includes, in order 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, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer 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 polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the first side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass 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. The basic parameter table of the optical system of this example is also the same as table 5 in example 7, and the higher order coefficient table of the aspherical mirror surface is also the same as table 6 in example 7.

This embodiment is also different from embodiment 7 in that the values of the effective half apertures T2d1 of the first side surface of the second lens E2 in the d1 direction are different, the values of the effective half apertures T2a2 of the second side surface of the second lens E2 in the a2 direction are different, the values of the effective half apertures T3a1, T3b1, T3c1, T3d1 of the first side surface of the third lens E3 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T3a2, T3b2, T3c2, T3d2 of the second side surface of the third lens in the a2, b2, c2, d2 directions are different. The values of T2d1, T2a2, T3a1, T3b1, T3c1, T3d1, T3a2, T3b2, T3c2, T3d2 in this example are also shown in table 7 below.

Fig. 10 shows on-axis chromatic aberration curves of the optical systems of examples 7, 8, and 9, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 11 shows astigmatism curves of the optical systems of examples 7, 8, and 9, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 12 shows distortion curves of the optical systems of example 7, example 8, and example 9, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 10 to 12, the optical systems given in embodiment 7, embodiment 8 and embodiment 9 can achieve good imaging quality.

In embodiments 1 to 9, the effective focal length f of the optical system, 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 distance TD of the second side of the first lens to the second side of the third lens on the optical axis, the central thickness CTR of the reflective polarizing element on the optical axis, the central thickness CTQ of the quarter wave plate on the optical axis, the maximum half field angle Semi-FOV of the optical system, the effective radius T2d1 of the first side of the second lens to the effective radius contour right edge of the first side of the second lens, the effective radius T2a2 of the effective radius T2 of the upper edge of the effective radius contour of the second side of the second lens, the effective radius T3a1 of the first side of the third lens to the upper edge of the effective radius contour of the first side of the third lens, the effective radius T3a1 of the third side of the third lens, the effective radius T3 of the third side of the third lens to the effective radius T2 of the third side of the third lens, the effective radius T3a1 of the third side of the third lens to the effective radius T3 of the third side of the third lens, the effective half-aperture T3c2 from the optical center of the second side of the third lens to the lower edge of the effective diameter profile of the second side of the third lens and the effective half-aperture T3d2 from the optical center of the second side of the third lens to the right edge of the effective diameter profile of the second side of the third lens are shown in table 7.

Parameters/embodiments	1	2	3	4	5	6	7	8	9
										f(mm)	20.64	20.64	20.64	22.96	22.96	22.96	20.47	20.47	20.47
f1(mm)	137.14	137.14	137.14	216.06	216.06	216.06	429.75	429.75	429.75
										f2(mm)	119.98	119.98	119.98	593.04	593.04	593.04	54.66	54.66	54.66
f3(mm)	233.28	233.28	233.28	176.89	176.89	176.89	672.87	672.87	672.87
										TD(mm)	16.67	16.67	16.67	14.87	14.87	14.87	18.58	18.58	18.58
CTR(mm)	0.09	0.09	0.09	0.10	0.10	0.10	0.09	0.09	0.09
										CTQ(mm)	0.09	0.09	0.09	0.10	0.10	0.10	0.09	0.09	0.09
Semi-FOV(°)	48.0	48.0	48.0	48.0	48.0	48.0	45.0	45.0	45.0
										T2d1(mm)	20.96	20.07	23.42	21.60	22.56	25.20	23.63	21.15	20.25
T2a2(mm)	17.17	15.39	19.62	16.56	18.48	21.12	19.80	17.33	15.53
										T3a1(mm)	17.55	16.15	20.18	16.56	18.00	20.70	19.40	16.88	15.53
T3b1(mm)	22.00	20.24	24.64	20.76	22.56	25.27	23.69	21.15	19.46
										T3c1(mm)	23.40	21.53	26.21	22.08	24.00	26.88	25.20	22.50	20.70
T3d1(mm)	22.00	20.24	24.64	20.76	22.56	25.27	23.69	21.15	19.46
										T3a2(mm)	17.55	16.15	20.18	17.25	18.75	21.56	19.40	16.88	15.53
T3b2(mm)	22.00	20.24	24.64	21.62	23.50	26.32	23.69	21.15	19.46
										T3c2(mm)	23.40	21.53	26.21	23.00	25.00	28.00	25.20	22.50	20.70
T3d2(mm)	22.00	20.24	24.64	21.62	23.50	26.32	23.69	21.15	19.46

TABLE 7

Examples 1 to 9 each satisfy the conditions shown in table 8.

Condition/example	1	2	3	4	5	6	7	8	9
										f/f3	0.09	0.09	0.09	0.13	0.13	0.13	0.03	0.03	0.03
(T3a2+T3c2)/f	1.98	1.83	2.25	1.75	1.91	2.16	2.18	1.92	1.77
										(R6/R5)×(T3b2/T3b1)	0.38	0.38	0.38	0.06	0.06	0.06	0.84	0.84	0.84
f3/(f1+f2)	0.91	0.91	0.91	0.22	0.22	0.22	1.39	1.39	1.39
										T3a1/T2a2	1.02	1.05	1.03	1.00	0.97	0.98	0.98	0.97	1.00
T3d1/T2d1	1.05	1.01	1.05	0.96	1.00	1.00	1.00	1.00	0.96
										T3d2/TD	1.32	1.21	1.48	1.45	1.58	1.77	1.27	1.14	1.05
(f×tan(Semi-FOV))/T3a2	1.31	1.42	1.14	1.48	1.36	1.18	1.05	1.21	1.32
										T3c1/R5	-0.11	-0.10	-0.12	-0.02	-0.02	-0.02	-0.33	-0.29	-0.27
CT3×(T3b1/T3b2)(mm)	3.60	3.60	3.60	3.69	3.69	3.69	2.87	2.87	2.87
										CT1×(CTR/CTQ)(mm)	6.52	6.52	6.52	5.04	5.04	5.04	5.58	5.58	5.58
R6/(T3b2+T3d2)	-1.82	-1.98	-1.63	-2.10	-1.93	-1.72	-1.36	-1.53	-1.66

TABLE 8

The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It should be understood by those skilled in the art that the scope of protection referred to in this application is not limited to the specific combination of the above technical features, but also encompasses other technical solutions formed by any combination of the above technical features or their equivalents without departing from the spirit of the application. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims

1. An optical system, comprising, in order from a first side to a second side along an optical axis:

a first lens having positive optical power;

a second lens having positive optical power, the second side of which is convex; and

a third lens with positive focal power, the first side surface of which is concave, and the second side surface of which is convex;

the optical system further includes: a reflective polarizing element and a quarter wave plate attached to the first side or the second side of the first lens;

The optical system satisfies:

0.02< f/f3<0.15, and

1.7<(T3a2+T3c2)/f<2.3，

wherein f is an effective focal length of the optical system, f3 is an effective focal length of the third lens, T3a2 is an effective half caliber from an optical center of the second side surface of the third lens to an upper edge of an effective diameter profile of the second side surface of the third lens, and T3c2 is an effective half caliber from an optical center of the second side surface of the third lens to a lower edge of the effective diameter profile of the second side surface of the third lens.

2. The optical system of claim 1, wherein the radius of curvature R6 of the second side of the third lens, the radius of curvature R5 of the first side of the third lens, the effective half-caliber T3b2 from the optical center of the second side of the third lens to the left edge of the effective diameter profile of the second side of the third lens, and the effective half-caliber T3b1 from the optical center of the first side of the third lens to the left edge of the effective diameter profile of the first side of the third lens satisfy:

0.05<(R6/R5)×(T3b2/T3b1)<0.85。

3. the optical system of claim 1, wherein an effective focal length f1 of the first lens and an effective focal length f2 of the second lens satisfy:

0.2<f3/(f1+f2)<1.4。

4. the optical system of claim 1, wherein an effective half-caliber T3a1 from an optical center of the first side of the third lens to an effective diameter profile upper edge of the first side of the third lens and an effective half-caliber T2a2 from an optical center of the second side of the second lens to an effective diameter profile upper edge of the second side of the second lens satisfy:

0.9<T3a1/T2a2<1.2。

5. The optical system of claim 1, wherein an effective half-caliber T3d1 from an optical center of the first side of the third lens to a right edge of an effective diameter profile of the first side of the third lens and an effective half-caliber T2d1 from an optical center of the first side of the second lens to a right edge of an effective diameter profile of the first side of the second lens satisfy:

0.9<T3d1/T2d1<1.1。

6. the optical system of claim 1, wherein an effective half-diameter T3d2 from an optical center of the second side of the third lens to a right edge of an effective diameter profile of the second side of the third lens and a distance TD on the optical axis from the first side of the first lens to the second side of the third lens satisfy:

1.0<T3d2/TD<1.8。

7. the optical system of claim 1, wherein a maximum half field angle Semi-FOV of the optical system satisfies:

1.0<(f×tan(Semi-FOV))/T3a2<1.5。

8. the optical system of claim 1, wherein an effective half-diameter T3c1 from an optical center of the first side of the third lens to a lower edge of an effective diameter profile of the first side of the third lens and a radius of curvature R5 of the first side of the third lens satisfy:

-0.4<T3c1/R5<0。

9. An optical system, comprising, in order from a first side to a second side along an optical axis:

a first lens having positive optical power;

the optical system satisfies:

0.02< f/f3<0.15, and

1.0<T3d2/TD<1.8，

wherein f is an effective focal length of the optical system, f3 is an effective focal length of the third lens, T3d2 is an effective half-caliber from an optical center of the second side surface of the third lens to a right edge of an effective diameter profile of the second side surface of the third lens, and TD is a distance from the first side surface of the first lens to the second side surface of the third lens on the optical axis.

10. A VR device comprising the optical system of any one of claims 1-9, wherein the first side is a human eye side and the second side is a display side.