CN116430558A

CN116430558A - Visual optical system

Info

Publication number: CN116430558A
Application number: CN202310155446.0A
Authority: CN
Inventors: 戴付建; 张晓彬; 金银芳; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2023-02-17
Filing date: 2023-02-17
Publication date: 2023-07-14

Abstract

The application discloses a visual optical system, include: a first lens, a second lens, a reflective polarizing element, a quarter wave plate, a third lens, and a display; the first lens and the third lens are sequentially arranged from the eye side to the display position along the optical axis; the reflective polarizing element and the quarter wave plate are arranged between the second lens and the third lens; the first lens, the second lens, the reflective polarizing element, the quarter wave plate and the third lens are respectively provided with at least one far light surface far away from the display and one near light surface near the display; the near light surface of the third lens is provided with a partial reflecting layer. The light is firstly changed into linear polarized light through the quarter wave plate, reflected when passing through the reflective polarizing element, changed into circular polarized light through the quarter wave plate again, reflected by the partial reflecting layer, and changed into orthogonal linear polarized light after the circular polarized light passes through the quarter wave plate again after being reversed, and can pass through the reflective polarizing element to realize the projection of objects on the display to human eyes.

Description

Visual optical system

Technical Field

The application belongs to the field of optical imaging, and particularly relates to a visual optical system.

Background

In recent years, a visual optical system device has been rapidly developed, and particularly a folded optical path structure has been receiving attention in the industry. The folding light path structure utilizes the polarization characteristic of light and combines the quarter wave plate and the reflective polarizer to enable the light path to be folded and compress the light path, thereby realizing the thinning aim of the visual optical system device.

In the folded light path structure, the material for light path deflection has higher stress requirements to ensure the polarization characteristic of light, meanwhile, in order to realize the light and thin design of the visual optical system device, the light and thin design is always a design target of various large visual optical system device manufacturers, which means that the length of the lens system is limited, so that the lens parameters are limited greatly, the design freedom of the lens system is compressed, the design freedom of the lens is expanded as much as possible in a limited size, and the optimization of the subsequent imaging quality and the adaptation of an image algorithm are convenient.

Disclosure of Invention

The application aims at providing a visual optical system, through improving imaging quality after turning to the light path, finally realize projecting the thing on the display to the human eye, make the people immerse in virtual world, simultaneously, realize the product demand that optical system's structure is frivolous.

The present application provides a visual optical system, the optical system comprising: a first lens, a second lens, a reflective polarizing element, a quarter wave plate, a third lens, and a display; the first lens to the third lens are sequentially arranged from the human eye side to the display position along the optical axis; the reflective polarizing element and the quarter wave plate are arranged between the second lens and the third lens; the first lens, the second lens, the reflective polarizing element, the quarter wave plate and the third lens respectively have at least one high beam surface far from the display and one low beam surface near to the display; the low beam surface of the third lens has a partially reflective layer; wherein a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, and an effective focal length f of the optical system satisfy: 0.5< FG23/f <2.0.

According to one embodiment of the present application, the radius of curvature R4 of the second lens near-light surface, the radius of curvature R5 of the third lens far-light surface, the radius of curvature R6 of the third lens near-light surface, and the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens satisfy: -10< (r4+r5+r6)/FG 23< -3.

According to one embodiment of the present application, the refractive index N1 of the first lens, the refractive index N2 of the second lens, and the refractive index Nr of the reflective polarizing element satisfy: 2< (N1+N2)/Nr <2.5.

According to one embodiment of the present application, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the refractive index Nq of the quarter wave plate satisfy: 3< (N1+N2+N3)/Nq <3.5.

According to one embodiment of the present application, the abbe number V1 of the first lens, the abbe number V2 of the second lens, the refractive index N1 of the first lens, and the refractive index N2 of the second lens satisfy: -26< V1/N1-V2/N2<25.

According to one embodiment of the present application, the maximum refractive index Nmax among the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, the abbe number V2 of the second lens, and the abbe number V3 of the third lens satisfy: 5< |V2+V3|/10Nmax <8.5.

According to one embodiment of the present application, the center thickness CT1 of the first lens on the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy: 1< CT3/CT1<8.

According to one embodiment of the present application, the center thickness CT2 of the second lens on the optical axis, the air interval T23 of the second lens and the third lens on the optical axis, with a relative F number Fno, satisfies: 3< CT2/T23 Xfno <36.

According to one embodiment of the present application, the radius of curvature R4 of the second lens proximal surface, the radius of curvature R5 of the third lens distal surface, and the radius of curvature R6 of the third lens proximal surface satisfy: 1.5< (R4+R5)/R6 <3.5.

According to one embodiment of the present application, the on-axis distance SAG21 between the intersection point of the second lens distal surface and the optical axis and the effective radius vertex of the second lens distal surface, and the on-axis distance SAG22 between the intersection point of the second lens proximal surface and the optical axis and the effective radius vertex of the second lens proximal surface satisfy: 10< (SAG21+SAG22)/(SAG 21-SAG 22) <3.

According to one embodiment of the present application, the radius of curvature R2 of the first lens proximal surface and the radius of curvature R4 of the second lens proximal surface satisfy: -3< R2/R4<5.5.

According to one embodiment of the present application, the on-axis distance TD from the far-light surface of the first lens to the near-light surface of the third lens, and the center thickness CT3 of the third lens on the optical axis, satisfy: 1< TD/CT3<3.

According to one embodiment of the present application, the high beam surface of the reflective polarizing element is at least partially in contact with the low beam surface of the second lens.

According to one embodiment of the present application, the light-proximal surface of the reflective polarizing element is at least partially in contact with the light-distal surface of the quarter-wave plate; the low beam surface of the quarter wave plate is at least partially in contact with the high beam surface of the third lens.

According to one embodiment of the present application, the low beam surface of the quarter wave plate is at least partially in contact with the high beam surface of the third lens.

The beneficial effects of this application:

the visual optical system provided by the application comprises a plurality of lenses, and the polarization state of light and the propagation direction of the light can be changed through the reflective polarizing element and the quarter wave plate between the second lens and the third lens and the partial reflective layer arranged on the near-light surface of the third lens: the light passes through the quarter wave plate, the circularly polarized light is changed into linearly polarized light, the linearly polarized light is reflected when passing through the reflective polarizing element, the light is changed into circularly polarized light again through the quarter wave plate, and then the circularly polarized light is reflected by the partial reflecting layer, and the circularly polarized light passes through the quarter wave plate again after being reflected, and becomes orthogonal linearly polarized light which can pass through the reflective polarizing element; the ratio of the focal length of the first lens to the effective focal length of the optical system is indirectly controlled by controlling the ratio of the combined focal length of the second lens to the effective focal length of the third lens to the effective focal length of the optical system, the focal power of the system is reasonably distributed, the architecture selection of the optical system is facilitated, the design freedom degree is improved, the imaging quality and the adaptation degree of an image algorithm are improved, and therefore the immersion effect of the visual optical system is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an optical system according to embodiment 1 of the present application;

FIGS. 2a to 2c are respectively an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system of example 1 of the present application;

FIG. 3 is a schematic view showing the structure of an optical system according to embodiment 2 of the present application;

FIGS. 4a to 4c are respectively an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system of example 2 of the present application;

FIG. 5 is a schematic view showing the structure of an optical system according to embodiment 3 of the present application;

FIGS. 6a to 6c are, respectively, on-axis chromatic aberration curves, astigmatism curves, and distortion curves of embodiment 3 of the optical system of the present application;

FIG. 7 is a schematic view showing the structure of an optical system according to embodiment 4 of the present application;

FIGS. 8a to 8c are, respectively, on-axis chromatic aberration curves, astigmatism curves, and distortion curves of the optical system of example 4 of the present application;

FIG. 9 is a schematic view showing the structure of an optical system according to embodiment 5 of the present application;

FIGS. 10a to 10c are, respectively, on-axis chromatic aberration curves, astigmatism curves, and distortion curves of example 5 of the optical system of the present application;

FIG. 11 is a schematic view showing the structure of an optical system according to embodiment 6 of the present application;

fig. 12a to 12c are an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve, respectively, of embodiment 6 of the optical system of the present application.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

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

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 features listed" appears after the list of features 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.

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.

In the description of the present application, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex location 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 concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the high beam surface of the lens, and the surface of each lens closest to the imaging surface is referred to as the low beam surface of the lens.

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 features, principles and other aspects of the present application are described in detail below with reference to the accompanying drawings and in connection with the embodiments.

Exemplary embodiments

The optical system of the present exemplary embodiment includes: a first lens, a second lens, a reflective polarizing element, a quarter wave plate, a third lens, and a display; the first lens and the third lens are sequentially arranged from the eye side to the display position along the optical axis; the reflective polarizing element and the quarter wave plate are arranged between the second lens and the third lens; the first lens, the second lens, the reflective polarizing element, the quarter wave plate and the third lens are respectively provided with at least one far light surface far away from the display and one near light surface near the display; the low beam surface of the third lens has a partially reflective layer. In the embodiment of the application, the optical system comprises three lenses, a reflective polarizing element, a quarter wave plate and a display, and forms a visual system, and the visual system can project objects on the display to human eyes so as to immerse the human eyes in a virtual world. The reflective polarizing element and the quarter wave plate are arranged between the second lens and the third lens, and the lower light surface of the third lens is provided with a partial reflecting layer which can change the polarization state of light and the propagation direction of the light: the light passes through the quarter wave plate first, the circularly polarized light is changed into linearly polarized light, the linearly polarized light is reflected when passing through the reflective polarizing element, the light is changed into circularly polarized light again through the quarter wave plate, then the circularly polarized light is reflected by the partial reflecting layer, and the circularly polarized light passes through the quarter wave plate again after being reflected, and becomes orthogonal linearly polarized light which can pass through the reflective polarizing element.

In the present exemplary embodiment, the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, and the effective focal length f of the optical system satisfy: 0.5< FG23/f <2.0. The ratio of the focal length of the first lens to the effective focal length of the optical system is indirectly controlled in a reasonable range by controlling the ratio of the combined focal length of the second lens to the effective focal length of the third lens to the effective focal length of the optical system, and the focal power of the system is reasonably distributed, so that the selection of the architecture of the optical system is facilitated. More specifically, the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, and the effective focal length f of the optical system, satisfy: 0.51< FG23/f <1.99

In the present exemplary embodiment, the radius of curvature R4 of the second lens near-light surface, the radius of curvature R5 of the third lens far-light surface, the radius of curvature R6 of the third lens near-light surface, and the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens satisfy: -10< (r4+r5+r6)/FG 23< -3. The ratio of the curvature radius of the second lens and the third lens to the combined focal length is controlled within a reasonable range, so that the center thickness of the second lens and the third lens and the air interval between the second lens and the third lens are restrained, and the combination stability of the second lens and the third lens is facilitated. More specifically, the radius of curvature R4 of the second lens element near-light surface, the radius of curvature R5 of the third lens element far-light surface, the radius of curvature R6 of the third lens element near-light surface, and the combined focal length FG23 of the second lens element, the reflective polarizing element, the quarter wave plate, and the third lens element satisfy the following conditions: -9.99< (r4+r5+r6)/FG 23< -3.01.

In the present exemplary embodiment, the refractive index N1 of the first lens, the refractive index N2 of the second lens, and the refractive index Nr of the reflective polarizing element satisfy: 2< (N1+N2)/Nr <2.5. The refractive indexes of the first lens, the second lens and the reflective polarizing element are controlled to enable the refractive index of the polarizing element to be close to that of the two lenses, so that the thickness selection of the reflective polarizing element is facilitated, and when the thickness of the reflective polarizing element is changed, the performance loss of the optical system can be minimized by changing the thickness of the lens. More specifically, the refractive index N1 of the first lens, the refractive index N2 of the second lens, and the refractive index Nr of the reflective polarizing element satisfy: 2.01< (N1+N2)/Nr <2.49.

In the present exemplary embodiment, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the refractive index Nq of the quarter wave plate satisfy: 3< (N1+N2+N3)/Nq <3.5. The refractive index of the quarter wave plate is equal to that of the lens by controlling the refractive indexes of the three lenses and the quarter wave plate, so that the performance loss caused by the change of the polarization state of light rays is reduced. More specifically, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the refractive index Nq of the quarter wave plate satisfy: 3.01< (N1+N2+N3)/Nq <3.49.

In the present exemplary embodiment, the abbe number V1 of the first lens, the abbe number V2 of the second lens, the refractive index N1 of the first lens, and the refractive index N2 of the second lens satisfy: -26< V1/N1-V2/N2<25. By controlling the ratio of the abbe numbers to the refractive indexes of the first lens and the second lens within a reasonable range, the aberration introduced by the third lens can be corrected, which is advantageous in improving the performance of the optical system. More specifically, the abbe number V1 of the first lens, the abbe number V2 of the second lens, the refractive index N1 of the first lens, and the refractive index N2 of the second lens satisfy: -26.01< V1/N1-V2/N2<24.99.

In the present exemplary embodiment, the maximum refractive index Nmax among the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, the abbe number V2 of the second lens, and the abbe number V3 of the third lens satisfy: 5< |V2+V3|/10Nmax <8.5. The ratio of Abbe numbers of the second lens and the third lens to the maximum refractive indexes of the polarizing element and the third lens is controlled within a reasonable range, so that chromatic aberration of the system can be corrected. More specifically, the maximum refractive index Nmax among the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, the abbe number V2 of the second lens, and the abbe number V3 of the third lens satisfy: 5.01< |V2+V3|/10Nmax <8.49.

In the present exemplary embodiment, the center thickness CT1 of the first lens on the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy: 1< CT3/CT1<8. The central thickness ratio of the third lens to the first lens is controlled within a reasonable range, so that the central thickness of the third lens is larger, the light path turning length can be increased, and the thickness of the visual optical system device is reduced. More specifically, the center thickness CT1 of the first lens on the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy: 1.01< CT3/CT1<7.99.

In the present exemplary embodiment, the center thickness CT2 of the second lens on the optical axis, the air interval T23 of the second lens and the third lens on the optical axis, with a relative F number Fno, satisfies: 3< CT2/T23 Xfno <36. The aperture of the optical system is restrained under the condition of a certain system focal length by controlling the center thickness of the second lens, the air interval behind the second lens and the optical system of F number, so that the intensity of the second lens is restrained, and the forming and assembling stability of the second lens are facilitated. More specifically, the center thickness CT2 of the second lens on the optical axis, the air space T23 of the second lens and the third lens on the optical axis, with a relative F number Fno, satisfies: 3.01< CT2/T23 Xfno <35.99.

In the present exemplary embodiment, the radius of curvature R4 of the second lens near-light surface, the radius of curvature R5 of the third lens far-light surface, and the radius of curvature R6 of the third lens near-light surface satisfy: 1.5< (R4+R5)/R6 <3.5. The curvature radius of the near-light surface of the second lens and the curvature radius of the two surfaces of the third lens are controlled, so that the shape of the lens is restrained, the incidence angle of light on the surface of the lens when the light is turned over is controlled, on one hand, the reflection efficiency of the near-light surface of the third lens is increased, and on the other hand, the polarization efficiency of the light when the light passes through the quarter wave plate and the reflective polarizing element is increased. More specifically, the radius of curvature R4 of the second lens proximal surface, the radius of curvature R5 of the third lens distal surface, and the radius of curvature R6 of the third lens proximal surface satisfy: 1.51< (R4+R5)/R6 <3.49.

In the present exemplary embodiment, the on-axis distance SAG21 between the intersection point of the second lens distal surface and the optical axis and the effective radius vertex of the second lens distal surface, and the on-axis distance SAG22 between the intersection point of the second lens proximal surface and the optical axis and the effective radius vertex of the second lens proximal surface satisfy: 10< (SAG21+SAG22)/(SAG 21-SAG 22) <3. The shape of the two sides of the second lens is controlled by controlling the sagittal height of the two sides of the second lens, which is beneficial to the molding of the second lens. More specifically, the on-axis distance SAG21 between the intersection point of the second lens distal surface and the optical axis and the effective radius vertex of the second lens distal surface, and the on-axis distance SAG22 between the intersection point of the second lens proximal surface and the optical axis and the effective radius vertex of the second lens proximal surface satisfy: -9.99< (sag21+sag22)/(SAG 21-SAG 22) <2.99.

In the present exemplary embodiment, the radius of curvature R2 of the first lens paraxial region and the radius of curvature R4 of the second lens paraxial region satisfy: -3< R2/R4<5.5. The ratio of the curvature radius of the first lens near-light surface to that of the second lens near-light surface is controlled within a reasonable range, so that the shapes of the first lens and the second lens are controlled, the two lenses are matched appropriately, and the assembly stability of the two lenses is facilitated. More specifically, the curvature radius R2 of the first lens paraxial region and the curvature radius R4 of the second lens paraxial region satisfy: -2.99< R2/R4<5.49.

In the present exemplary embodiment, the on-axis distance TD from the high beam surface of the first lens to the near beam surface of the third lens, and the center thickness CT3 of the third lens on the optical axis satisfy: 1< TD/CT3<3. The ratio of the axial distance from the first lens to the third lens to the thickness of the center of the third lens is controlled within a reasonable range, so that the third lens is thicker, the length of the light beam folded at the third lens is increased, and the thickness of the visual optical system device is reduced. More specifically, the on-axis distance TD from the far-light surface of the first lens to the near-light surface of the third lens, and the center thickness CT3 of the third lens on the optical axis, satisfy: 1.01< TD/CT3<2.99.

In the present exemplary embodiment, the light-transmitting surface of the reflective polarizing element is at least partially in contact with the light-transmitting surface of the second lens. In this embodiment, the reflective polarizing element is attached to the near-light surface of the second lens, so that the light is only folded at the third lens and the air space between the second lens and the third lens, which is beneficial to increasing the folded length of the light.

In the present exemplary embodiment, the light-proximal surface of the reflective polarizing element is at least partially in contact with the light-distal surface of the quarter-wave plate; the low beam surface of the quarter wave plate is at least partially in contact with the high beam surface of the third lens. In the embodiment of the application, the reflective polarizing element and the quarter wave plate are combined together, so that the curved surface film pasting process flow is reduced; the quarter wave plate is attached to the far-light surface of the third lens, so that light rays are only reflected at the third lens, and image quality loss caused by assembly tolerance of the second lens and the third lens is reduced.

In this exemplary embodiment, the low beam surface of the quarter wave plate is at least partially in contact with the high beam surface of the third lens. In the embodiment of the application, the near light surface of the quarter wave plate is attached to the far light surface of the third lens, so that light rays are only reflected on the third lens, and on one hand, the image quality loss caused by the assembly tolerance of the second lens and the third lens is reduced; on the other hand, the risk of ghost images caused by light rays which are folded back between a plurality of elements is reduced.

In the present exemplary embodiment, the distance light surface and the near light surface of any one of the first lens E1 to the third lens E3 are aspherical surfaces, and the surface profile x of each aspherical lens may be defined by, but not limited to, the following aspherical 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); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspherical surface.

In the present exemplary embodiment, the above-described optical system may further include a diaphragm. The diaphragm may be disposed at an appropriate position as needed, for example, the diaphragm may be disposed between the object side and the first lens. Optionally, the optical system may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element located on the imaging surface.

The optical system according to the above-described embodiments of the present application may employ a plurality of lenses, for example, three lenses as described above. The focal power, the surface shape, the center thickness of each lens, the axial spacing between each lens and the like of each lens are reasonably distributed, so that the optical system has a larger imaging image surface, has the characteristics of wide imaging range and high imaging quality, and ensures the ultra-thin performance of the mobile phone.

In an exemplary embodiment, at least one of the mirrors of each lens is an aspherical mirror, i.e., at least one of the far-light surface of the first lens to the far-light surface of the third lens is an aspherical mirror. The aspherical lens is characterized in that: unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better radius of curvature characteristic, and has advantages of improving distortion aberration and improving astigmatic aberration. By adopting the aspherical lens, aberration occurring at the time of imaging can be eliminated as much as possible, thereby improving imaging quality. Optionally, at least one of the distal surface and the proximal surface of each of the first lens, the second lens, and the third lens is an aspherical mirror surface. Optionally, the distance light surface and the near light surface of each of the first lens, the second lens and the third lens are aspheric mirrors.

However, those skilled in the art will appreciate that the number of lenses making up an optical system can be varied to achieve the various results and advantages described in this specification without departing from the technical solutions claimed herein. For example, although three lenses are described as an example in the embodiment, the optical system is not limited to including three lenses, and may include other numbers of lenses if necessary.

Specific embodiments of an optical system suitable for the above-described embodiments are further described below with reference to the accompanying drawings.

Example 1

Fig. 1 is a schematic structural diagram of an optical system embodiment 1 of the present application, where the optical system includes: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

The first E1 lens to the third E3 lens are sequentially arranged from the human eye side to the display position along the optical axis; a reflective polarizing element RP and a quarter wave plate QWP are sequentially arranged between the second lens E2 and the third lens E3; the first lens E1, the second lens E2, the reflective polarizer RP, the quarter wave plate QWP and the third lens E3 have a high beam surface far from the display and a low beam surface near the display, respectively. The high beam side of the third lens E3 has a partially reflective layer.

As shown in table 1, the basic parameters of the optical system of example 1 are shown, wherein the units of radius of curvature, thickness, and focal length are all millimeters (mm).

TABLE 1

As shown in table 2, in embodiment 1, the total effective focal length f=26.63 mm of the optical system, and the distance ttl=29.99 mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 2

The optical system in embodiment 1 satisfies:

FG 23/f=1.08, where FG23 is the combined focal length of the second lens, reflective polarizing element, quarter wave plate, and third lens, and f is the effective focal length of the optical system.

(r4+r5+r6)/FG 23= -3.77, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, R6 is the radius of curvature of the third lens ' proximal surface, FG23 is the combined focal length of the second lens, reflective polarizer, quarter wave plate, and third lens.

(n1+n2)/nr=2.05, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, and Nr is the refractive index of the reflective polarizing element.

(n1+n2+n3)/nq=3.08, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, N3 is the refractive index of the third lens, and Nq is the refractive index of the quarter wave plate.

V1/N1-V2/n2=0.00, where V1 is the abbe number of the first lens, V2 is the abbe number of the second lens, N1 is the refractive index of the first lens, and N2 is the refractive index of the second lens.

V2+v3|/10nmax=7.27, where Nmax is the maximum refractive index of the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, V2 is the abbe number of the second lens, and V3 is the abbe number of the third lens.

CT 3/ct1=2.82, wherein CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno=8.15, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space of the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(r4+r5)/r6=1.82, where R4 is a radius of curvature of the second lens proximal surface, R5 is a radius of curvature of the third lens distal surface, and R6 is a radius of curvature of the third lens proximal surface.

(sag21+sag22)/(SAG 21-SAG 22) = -9.28, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4=5.02, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

TD/CT3 = 2.69, where TD is the on-axis distance from the far-light surface of the first lens to the near-light surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

In example 1, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and table 3 shows the higher order coefficients a that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 1 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

Face number	A4	A6	A8	A10
					S1	-6.2068E-02	-5.7943E-02	2.2887E-03	2.6299E-02
S2	-1.0750E-01	-2.9584E-01	3.0540E-02	4.5909E-02
					S3	1.1798E-01	2.3214E-01	-5.9860E-02	5.3373E-02
S4	-3.8381E-02	3.4172E-01	-4.6661E-02	1.8129E-02
					S7	4.1356E-02	3.2488E-02	2.2439E-01	-7.4613E-02
S8	2.3923E-01	4.9481E-02	8.8259E-03	-6.1318E-03

TABLE 3 Table 3

Fig. 2a shows an on-axis chromatic aberration curve of the optical system of embodiment 1, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the lens. Fig. 2b shows an astigmatism curve of the optical system of example 1, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 2c shows a distortion curve of the optical system of example 1, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 2a to 2c, the optical system according to embodiment 1 can achieve good imaging quality.

Example 2

Fig. 3 is a schematic structural diagram of an optical system in embodiment 2 of the present application, the optical system includes: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

As shown in table 4, the basic parameters of the optical system of example 2 are shown, wherein the units of radius of curvature, thickness, and focal length are all millimeters (mm).

TABLE 4 Table 4

As shown in table 5, in embodiment 2, the total effective focal length f=28.45 mm of the optical system, and the distance ttl=29.99 mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 5

The optical system in embodiment 2 satisfies:

FG 23/f=1.19, where FG23 is the combined focal length of the second lens, reflective polarizing element, quarter wave plate, and third lens, and f is the effective focal length of the optical system.

(r4+r5+r6)/FG 23= -6.17, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, R6 is the radius of curvature of the third lens ' proximal surface, FG23 is the combined focal length of the second lens, reflective polarizer, quarter wave plate, and third lens.

(n1+n2)/nr=2.14, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, and Nr is the refractive index of the reflective polarizing element.

(n1+n2+n3)/nq=3.17, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, N3 is the refractive index of the third lens, and Nq is the refractive index of the quarter wave plate.

V1/N1-V2/n2=24.99, where V1 is the abbe number of the first lens, V2 is the abbe number of the second lens, N1 is the refractive index of the first lens, and N2 is the refractive index of the second lens.

V2+v3|/10nmax=4.49, where Nmax is the maximum refractive index of the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, V2 is the abbe number of the second lens, and V3 is the abbe number of the third lens.

CT 3/ct1=1.90, where CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno=3.92, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space of the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(r4+r5)/r6=2.78, where R4 is a radius of curvature of the second lens proximal surface, R5 is a radius of curvature of the third lens distal surface, and R6 is a radius of curvature of the third lens proximal surface.

(sag21+sag22)/(SAG 21-SAG 22) =5.31, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4=0.89, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

TD/CT3 = 2.13, where TD is the on-axis distance from the far-light surface of the first lens to the near-light surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

In example 2, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and Table 6 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 2 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

Face number	A4	A6	A8	A10
					S1	-2.4103E-01	-2.1493E-01	6.9071E-03	-8.5895E-03
S2	1.3770E-01	-2.2978E-01	-7.4459E-02	1.5565E-02
					S3	1.2197E-01	3.1781E-01	-8.1798E-02	2.8712E-04
S4	-3.0442E-02	1.0082E-01	9.1627E-02	-2.2374E-02
					S7	2.6607E-01	6.6022E-02	3.5223E-02	4.8705E-02
S8	-7.4565E-02	1.0880E-01	7.9410E-03	-3.7533E-04

TABLE 6

Fig. 4a shows an on-axis chromatic aberration curve of the optical system of embodiment 2, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the lens. Fig. 4b shows an astigmatism curve of the optical system of example 2, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 4c shows a distortion curve of the optical system of example 2, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 4a to 4c, the optical system according to embodiment 2 can achieve good imaging quality.

Example 3

Fig. 5 is a schematic structural diagram of an optical system in embodiment 3 of the present application, the optical system includes: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

As shown in table 7, the basic parameters of the optical system of example 3 were shown, wherein the units of radius of curvature, thickness, and focal length were all millimeters (mm).

TABLE 7

As shown in table 8, in embodiment 3, the total effective focal length f=26.63 mm of the optical system, and the distance ttl=29.99 mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 8

The optical system in embodiment 3 satisfies:

CT 3/ct1=2.83, where CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno=8.17, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space of the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(sag21+sag22)/(SAG 21-SAG 22) = -9.31, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4=5.03, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

In example 3, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and Table 9 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 3 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

Face number	A4	A6	A8	A10
					S1	-5.8364E-02	-5.8442E-02	2.4239E-03	2.6687E-02
S2	-1.0750E-01	-2.9590E-01	3.0991E-02	4.6645E-02
					S3	7.6651E-02	2.4256E-01	-6.2274E-02	5.4120E-02
S4	-5.0433E-02	3.4333E-01	-4.7694E-02	1.8296E-02
					S7	3.4344E-02	3.0611E-02	2.2525E-01	-7.5393E-02
S8	2.3321E-01	5.0190E-02	8.5167E-03	-6.1455E-03

TABLE 9

Fig. 6a shows an on-axis chromatic aberration curve of the optical system of embodiment 3, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the lens. Fig. 6b shows an astigmatism curve of the optical system of example 3, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 6c shows a distortion curve of the optical system of example 3, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 6a to 6c, the optical system according to embodiment 3 can achieve good imaging quality.

Example 4

Fig. 7 is a schematic structural diagram of an optical system of embodiment 4 of the present application, the optical system including: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

As shown in table 10, the basic parameters of the optical system of example 4 were shown, wherein the units of radius of curvature, thickness, and focal length were all millimeters (mm).

Table 10

As shown in table 11, in embodiment 4, the total effective focal length f=29.87 mm of the optical system, and the distance ttl= 30.98mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 11

The optical system in embodiment 4 satisfies:

FG 23/f=0.96, where FG23 is the combined focal length of the second lens, reflective polarizing element, quarter wave plate, and third lens, and f is the effective focal length of the optical system.

(r4+r5+r6)/FG 23= -7.37, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, R6 is the radius of curvature of the third lens ' proximal surface, FG23 is the combined focal length of the second lens, reflective polarizer, quarter wave plate, and third lens.

(n1+n2)/nr=2.15, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, and Nr is the refractive index of the reflective polarizing element.

(n1+n2+n3)/nq=3.15, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, N3 is the refractive index of the third lens, and Nq is the refractive index of the quarter wave plate.

V1/N1-V2/n2= -23.19, where V1 is the abbe number of the first lens, V2 is the abbe number of the second lens, N1 is the refractive index of the first lens, and N2 is the refractive index of the second lens.

V2+v3|/10nmax=8.01, where Nmax is the maximum refractive index of the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, V2 is the abbe number of the second lens, and V3 is the abbe number of the third lens.

CT 3/ct1=7.87, wherein CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno= 30.98, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space between the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(r4+r5)/r6=2.61, where R4 is a radius of curvature of the second lens proximal surface, R5 is a radius of curvature of the third lens distal surface, and R6 is a radius of curvature of the third lens proximal surface.

(sag21+sag22)/(SAG 21-SAG 22) = -0.44, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4= -2.13, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

TD/CT3 = 1.72, where TD is the on-axis distance from the far-light surface of the first lens to the near-light surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

In example 4, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and Table 12 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 4 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

Face number	A4	A6	A8	A10
					S1	-6.6537E-02	-1.5579E-01	-1.0627E-01	1.3356E-02
S2	-1.0460E-02	-3.4232E-01	-1.7173E-01	-2.0332E-02
					S3	-7.9799E-02	-2.7833E-01	-1.0099E-01	-1.9830E-02
S4	-8.1178E-02	-1.1870E-01	4.2704E-04	2.3704E-02
					S7	2.8672E-01	-2.9025E-03	2.8759E-03	-8.1075E-04
S8	1.1272E-01	-9.1425E-04	-3.7528E-03	-8.9808E-05

Table 12

Fig. 8a shows an on-axis chromatic aberration curve of the optical system of embodiment 4, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the lens. Fig. 8b shows an astigmatism curve of the optical system of example 4, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 8c shows a distortion curve of the optical system of example 4, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 8a to 8c, the optical system according to embodiment 4 can achieve good imaging quality.

Example 5

Fig. 9 is a schematic structural diagram of an optical system of embodiment 5 of the present application, the optical system including: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

As shown in table 13, the basic parameters of the optical system of example 5 were shown, wherein the units of radius of curvature, thickness, and focal length were all millimeters (mm).

TABLE 13

As shown in table 14, in embodiment 5, the total effective focal length f=29.87 mm of the optical system, and the distance ttl= 30.98mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 14

The optical system in embodiment 5 satisfies:

FG 23/f=0.85, where FG23 is the combined focal length of the second lens, reflective polarizing element, quarter wave plate, and third lens, and f is the effective focal length of the optical system.

(r4+r5+r6)/FG 23= -8.99, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, R6 is the radius of curvature of the third lens ' proximal surface, FG23 is the combined focal length of the second lens, reflective polarizer, quarter wave plate, and third lens.

(n1+n2)/nr=2.19, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, and Nr is the refractive index of the reflective polarizing element.

(n1+n2+n3)/nq=3.29, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, N3 is the refractive index of the third lens, and Nq is the refractive index of the quarter wave plate.

V1/N1-V2/n2= -25.84, where V1 is the abbe number of the first lens, V2 is the abbe number of the second lens, N1 is the refractive index of the first lens, and N2 is the refractive index of the second lens.

V2+v3|/10nmax=7.01, where Nmax is the maximum refractive index of the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, V2 is the abbe number of the second lens, and V3 is the abbe number of the third lens.

CT 3/ct1=3.80, wherein CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno=35.58, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space of the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(r4+r5)/r6=3.16, where R4 is a radius of curvature of the second lens proximal surface, R5 is a radius of curvature of the third lens distal surface, and R6 is a radius of curvature of the third lens proximal surface.

(sag21+sag22)/(SAG 21-SAG 22) = -0.52, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4= -2.53, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

TD/CT3 = 2.21, where TD is the on-axis distance from the far-light surface of the first lens to the near-light surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

In example 5, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and Table 15 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 5 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

TABLE 15

Fig. 10a shows an on-axis chromatic aberration curve of the optical system of embodiment 5, which represents the deviation of the converging focus after passing light rays of different wavelengths through the lens. Fig. 10b shows an astigmatism curve of the optical system of example 5, which represents meridional image surface curvature and sagittal image surface curvature. Fig. 10c shows a distortion curve of the optical system of example 5, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 10a to 10c, the optical system according to embodiment 5 can achieve good imaging quality.

Example 6

Fig. 11 is a schematic structural diagram of an optical system of embodiment 6 of the present application, the optical system including: stop STO, first lens E1, second lens E2, reflective polarizer RP, quarter wave plate QWP, third lens E3, display.

As shown in table 16, the basic parameters of the optical system of example 6 were shown, wherein the units of radius of curvature, thickness, and focal length were all millimeters (mm).

Table 16

As shown in table 17, in embodiment 6, the total effective focal length f=29.97 mm of the optical system, and the distance ttl=31.00 mm on the optical axis from the telephoto surface S1 of the first lens E1 to the imaging surface of the optical system.

TABLE 17

The optical system in embodiment 6 satisfies:

FG 23/f=1.56, where FG23 is the combined focal length of the second lens, reflective polarizing element, quarter wave plate, and third lens, and f is the effective focal length of the optical system.

(r4+r5+r6)/FG 23= -5.82, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, R6 is the radius of curvature of the third lens ' proximal surface, FG23 is the combined focal length of the second lens, reflective polarizer, quarter wave plate, and third lens.

(n1+n2)/nr=2.22, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, and Nr is the refractive index of the reflective polarizing element.

(n1+n2+n3)/nq=3.25, where N1 is the refractive index of the first lens, N2 is the refractive index of the second lens, N3 is the refractive index of the third lens, and Nq is the refractive index of the quarter wave plate.

V1/N1-V2/n2= 24.83, where V1 is the abbe number of the first lens, V2 is the abbe number of the second lens, N1 is the refractive index of the first lens, and N2 is the refractive index of the second lens.

V2+v3|/10nmax=5.23, where Nmax is the maximum refractive index of the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, V2 is the abbe number of the second lens, and V3 is the abbe number of the third lens.

CT 3/ct1=1.71, wherein CT1 is the center thickness of the first lens on the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

CT2/t23×fno=7.20, where CT2 is the center thickness of the second lens on the optical axis, T23 is the air space of the second lens and the third lens on the optical axis, and Fno is the relative F-number.

(r4+r5)/r6=3.05, where R4 is the radius of curvature of the second lens ' proximal surface, R5 is the radius of curvature of the third lens ' distal surface, and R6 is the radius of curvature of the third lens ' proximal surface.

(sag21+sag22)/(SAG 21-SAG 22) =2.59, wherein SAG21 is the on-axis distance between the intersection of the second lens distal surface and the optical axis to the effective radius vertex of the second lens distal surface, and SAG22 is the on-axis distance between the intersection of the second lens proximal surface and the optical axis to the effective radius vertex of the second lens proximal surface.

R2/r4=0.33, where R2 is the radius of curvature of the first lens 'proximal surface and R4 is the radius of curvature of the second lens' proximal surface.

TD/CT3 = 1.65, where TD is the on-axis distance from the far-light surface of the first lens to the near-light surface of the third lens, and CT3 is the center thickness of the third lens on the optical axis.

In example 6, the distance and near light surfaces of any one of the first to third lenses E1 to E3 are aspherical, and Table 18 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S1, S2, S3, S4, S7 and S8 in example 6 ₄ 、A ₆ 、A ₈ And A ₁₀ 。

Face number	A4	A6	A8	A10
					S1	-2.4442E-01	-8.2261E-02	7.6604E-03	4.3819E-05
S2	-8.6047E-02	1.7941E-01	-9.1849E-03	-1.4291E-02
					S3	4.5472E-01	8.6253E-02	-3.7131E-02	-5.4029E-03
S4	-4.2015E-01	-1.5530E-01	3.6077E-02	-1.0629E-04
					S7	3.1915E-02	-1.9514E-02	1.7659E-02	4.9350E-03
S8	4.5520E-02	-1.7004E-03	2.1327E-03	6.8725E-04

TABLE 18

Fig. 12a shows an on-axis chromatic aberration curve of the optical system of example 6, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the lens. Fig. 12b shows an astigmatism curve of the optical system of example 6, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 12c shows a distortion curve of the optical system of example 6, which represents the magnitude of distortion at different viewing angles. As can be seen from fig. 12a to 12c, the optical system according to embodiment 6 can achieve good imaging quality.

The foregoing description of the preferred embodiments of the present invention is not intended to limit the invention to the precise form disclosed, and any such modifications, improvements, equivalents, and so forth which fall within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

1. A visual optical system, the optical system comprising: a first lens, a second lens, a reflective polarizing element, a quarter wave plate, a third lens, and a display;

the first lens to the third lens are sequentially arranged from the human eye side to the display position along the optical axis;

the reflective polarizing element and the quarter wave plate are arranged between the second lens and the third lens;

the first lens, the second lens, the reflective polarizing element, the quarter wave plate and the third lens respectively have at least one high beam surface far from the display and one low beam surface near to the display;

the low beam surface of the third lens has a partially reflective layer;

wherein a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, and an effective focal length f of the optical system satisfy: 0.5< FG23/f <2.0.

2. The visual optical system of claim 1, wherein a radius of curvature R4 of the second lens ' proximal surface, a radius of curvature R5 of the third lens ' distal surface, a radius of curvature R6 of the third lens ' proximal surface, and a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter wave plate, and the third lens satisfy:

-10<(R4+R5+R6)/FG23<-3。

3. the visual optical system according to claim 1, wherein a refractive index N1 of the first lens, a refractive index N2 of the second lens, and a refractive index Nr of the reflective polarizing element satisfy: 2< (N1+N2)/Nr <2.5.

4. The visual optical system of claim 1, wherein the refractive index N1 of the first lens, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the refractive index Nq of the quarter wave plate satisfy: 3< (N1+N2+N3)/Nq <3.5.

5. The visual optical system according to claim 1, wherein an abbe number V1 of the first lens, an abbe number V2 of the second lens, a refractive index N1 of the first lens, and a refractive index N2 of the second lens satisfy:

-26<V1/N1-V2/N2<25。

6. The visual optical system according to claim 1, wherein a maximum refractive index Nmax among the first lens, the second lens, the reflective polarizing element, the quarter wave plate, and the third lens, an abbe number V2 of the second lens, and an abbe number V3 of the third lens satisfy: 5< |V2+V3|/10Nmax <8.5.

7. The visual optical system according to claim 1, wherein a center thickness CT1 of the first lens on the optical axis and a center thickness CT3 of the third lens on the optical axis satisfy: 1< CT3/CT1<8.

8. The visual optical system according to claim 1, wherein a center thickness CT2 of the second lens on the optical axis, an air interval T23 of the second lens and the third lens on the optical axis, and a relative F-number Fno, satisfy: 3< CT2/T23 Xfno <36.

9. The visual optical system of claim 1, wherein the radius of curvature R4 of the second lens proximal surface, the radius of curvature R5 of the third lens distal surface, and the radius of curvature R6 of the third lens proximal surface satisfy: 1.5< (R4+R5)/R6 <3.5.

10. The visual optical system of claim 1, wherein an on-axis distance SAG21 between an intersection of the second lens distal surface and the optical axis and an effective radius vertex of the second lens distal surface, and an on-axis distance SAG22 between an intersection of the second lens proximal surface and the optical axis and an effective radius vertex of the second lens proximal surface satisfy:

-10<(SAG21+SAG22)/(SAG21-SAG22)<3。