CN219978615U

CN219978615U - Optical system

Info

Publication number: CN219978615U
Application number: CN202320632167.4U
Authority: CN
Inventors: 陈威望; 游金兴; 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: 2023-03-24
Filing date: 2023-03-24
Publication date: 2023-11-07
Anticipated expiration: 2033-03-24

Abstract

The application discloses an optical system, which comprises a lens barrel, a lens group and a spacing element group, wherein the lens group and the spacing element group are arranged in the lens barrel, the lens group comprises a first lens, a second lens and a third lens which are sequentially arranged from a first side to a second side along an optical axis, and a reflective polarizing element and a quarter wave plate are sequentially arranged between the second lens and the third lens; the spacer element group comprises a first spacer element arranged between the first lens and the second lens and contacting the second side surface of the first lens; wherein, the inner diameter d0s of the first side end surface of the lens barrel, the interval EP01 of the first side end surface of the lens barrel and the first interval element along the optical axis, the curvature radius R2 of the second side surface of the first lens and the total effective focal length f of the optical system satisfy: 10< d0s/EP01+|R2/f| <36.

Description

Optical system

Technical Field

The application relates to the field of optical devices, in particular to an optical system.

Background

With the concept of "meta-universe" being proposed, the manner of entertainment for users is increasingly abundant, and devices such as Virtual Reality (VR)/augmented Reality (Augmented Reality, AR) technology of human-computer interaction are increasingly favored by users. Among these, miniaturization and high imaging quality of VR/AR devices are important factors affecting the user experience.

The optical system used by the conventional VR/AR device generally has defects of large volume, dizziness and the like, and the defects can lead the VR/AR device to have larger volume and poorer imaging quality, so that the VR/AR device cannot realize miniaturization and high imaging quality, and the experience of a user is seriously affected.

Disclosure of Invention

The present utility model provides an optical system that at least solves or partially solves at least one problem, or other problems, present in the prior art.

An aspect of the present utility model provides an optical system including a lens barrel, and a lens group and a spacer element group disposed in the lens barrel, the lens group including a first lens, a second lens, and a third lens sequentially arranged from a first side to a second side along an optical axis, wherein a reflective polarizing element and a quarter-wave plate are sequentially disposed between the second lens and the third lens; the spacer element group comprises a first spacer element arranged between the first lens and the second lens and contacting the second side surface of the first lens; wherein, the inner diameter d0s of the first side end surface of the lens barrel, the interval EP01 of the first side end surface of the lens barrel and the first interval element along the optical axis, the curvature radius R2 of the second side surface of the first lens and the total effective focal length f of the optical system satisfy: 10< d0s/EP01+|R2/f| <36.

According to an exemplary embodiment of the application, the first side or the second side of the third lens is provided with a partially reflective layer.

According to an exemplary embodiment of the present application, the first side of the reflective polarizing element is attached to the second side of the second lens, and the second side of the quarter-wave plate is attached to the first side of the third lens.

According to an exemplary embodiment of the present application, the second side of the reflective polarizing element is attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate is attached to the first side of the third lens.

According to an exemplary embodiment of the application, the spacer element group further comprises a second spacer element arranged between the second lens and the third lens and in contact with the second side of the second lens, wherein the radius of curvature R4 of the second side of the second lens, the radius of curvature R5 of the first side of the third lens and the inner diameter d2s of the first side of the second spacer element satisfy: -3< (R4+R5)/d 2s < -1 >.

According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed between the second lens and the third lens and in contact with the second side surface of the second lens, wherein a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens, a first side end surface of the lens barrel, and a spacing EP01 of the first spacer element along the optical axis satisfy: 2.0< FG23/(EP 01+EP 12) <6.0.

According to an exemplary embodiment of the present application, the length L of the lens barrel in the direction of the optical axis, the center thickness CT1 of the first lens on the optical axis, and the center thickness CT2 of the second lens on the optical axis satisfy: 3<L/(CT1+CT2) <5.

According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed between the second lens and the third lens and in contact with the second side surface of the second lens, wherein a spacing EP02 of the first side end surface of the lens barrel and the second spacer element along the optical axis and a center thickness CT1 of the first lens on the optical axis satisfy: 1.0< EP02/CT1<7.0.

According to an exemplary embodiment of the present application, the length L of the lens barrel in the direction of the optical axis, the interval EP02 of the first side end surface of the lens barrel and the second interval element along the optical axis, and the relative F number Fno of the optical system satisfy: 13< L/EP02×FNo <30.

According to an exemplary embodiment of the present application, the inner diameter D0s of the first side end surface of the lens barrel, the outer diameter D0s of the first side end surface of the lens barrel, the radius of curvature R5 of the first side surface of the third lens, and the radius of curvature R6 of the second side surface of the third lens satisfy: -53< (R5+R6)/|D0s-d0s| < 5.0.

According to an exemplary embodiment of the present application, the abbe number V2 of the second lens, the refractive index N2 of the second lens, the total effective focal length f of the optical system, and the on-axis distance TD from the first side of the first lens to the second side of the third lens satisfy: 11< (V2/N2) × (f/TD) <45.

According to an exemplary embodiment of the present application, the on-axis distance TD from the first side surface of the first lens to the second side surface of the third lens satisfies the following with the interval EP01 along the optical axis between the first side end surface of the lens barrel and the first interval element: 3< TD/EP01<11.

According to an exemplary embodiment of the present application, the inner diameter D1s of the first side surface of the first spacer element, the outer diameter D1s of the first side surface of the first spacer element and the central thickness CT1 of the first lens on the optical axis satisfy: 2< (D1 s-D1 s)/CT 1<15.

According to an exemplary embodiment of the present application, the spacer element group further includes a second spacer element disposed between the second lens and the third lens and in contact with the second side surface of the second lens, wherein a spacing P2m of the second spacer element and the second side end surface of the lens barrel along the optical axis, a center thickness CT2 of the second lens on the optical axis, and an air spacing T23 of the second lens and the third lens along the optical axis satisfy: 2< P2 m/(CT 2+ T23) <5.

The application can restrict the surface shape of the first lens by limiting the ratio of the curvature radius of the second side surface of the first lens to the total effective focal length of the optical system within a certain range, thereby controlling the emergent angle of light rays at the first lens and improving the imaging quality of the optical system; meanwhile, the inner diameter of the first side end face of the lens barrel and the interval between the first side end face of the lens barrel and the first interval element along the optical axis are controlled in a matched mode, the thickness of a non-optical effective part of the first lens is limited, the machinability of the first lens is guaranteed, the optical system is more compact, and the miniaturization of the optical system is achieved.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the accompanying drawings in which:

fig. 1 shows a schematic parametric diagram of an optical system according to the application;

fig. 2 shows a schematic configuration of an optical system of example 1 according to a first embodiment of the present application;

fig. 3 shows a schematic configuration of an optical system of example 2 according to a first embodiment of the present application;

fig. 4 shows a schematic structural view of an optical system of example 3 according to a first embodiment of the present application;

fig. 5A to 5C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve, respectively, of the optical system according to the first embodiment of the present application;

fig. 6 shows a schematic structural view of an optical system of example 1 according to a second embodiment of the present application;

fig. 7 shows a schematic configuration of an optical system of example 2 according to a second embodiment of the present application;

fig. 8 shows a schematic structural view of an optical system of example 3 according to a second embodiment of the present application;

fig. 9A to 9C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve, respectively, of an optical system according to a second embodiment of the present application;

Fig. 10 shows a schematic structural view of an optical system of example 1 according to a third embodiment of the present application;

fig. 11 shows a schematic structural view of an optical system of example 2 according to a third embodiment of the present application;

fig. 12 is a schematic view showing the structure of an optical system of example 3 according to a third embodiment of the present application; and

fig. 13A to 13C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve, respectively, of an optical system according to a third embodiment of the present application.

Detailed Description

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the application and is not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification.

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.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. Specifically, 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. The surface of each lens closest to the first side (e.g., the human eye side) is referred to as the first side of the lens, and the surface of each lens closest to the second side (e.g., the display screen side) is referred to as the second side of the lens.

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 describing embodiments of the application, use of "may" means "one or more embodiments of the 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, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

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

Fig. 1 shows a schematic diagram of parameters of an optical system according to an exemplary embodiment of the application. As shown in fig. 1, D1s denotes an inner diameter of the first side surface of the first spacer element, D1s denotes an outer diameter of the first side surface of the first spacer element, D2s denotes an inner diameter of the first side surface of the second spacer element, D0s denotes an inner diameter of the first side end surface of the lens barrel, D0s denotes an outer diameter of the first side end surface of the lens barrel, EP01 denotes a spacing of the first side end surface of the lens barrel and the first spacer element along the optical axis, EP12 denotes a spacing of the first spacer element and the second spacer element along the optical axis, EP02 denotes a spacing of the first side end surface of the lens barrel and the second spacer element along the optical axis, P2m denotes a spacing of the second spacer element and the second side end surface of the lens barrel along the optical axis, and L denotes a length of the lens barrel in a direction in which the optical axis is located.

As shown in fig. 2 to 4, 6 to 8, and 10 to 12, an optical system according to an exemplary embodiment of the present application may include a lens barrel and a lens group disposed within the lens barrel, and the lens group may include a first lens, a second lens, and a third lens sequentially arranged from a first side to a second side along an optical axis. In the first lens to the third lens, an air space may be provided between any adjacent two lenses. A reflective polarizing element and a quarter wave plate may be disposed between the second lens and the third lens in this order.

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 screen side. Accordingly, the first side of each element (first lens, second lens, third lens, reflective polarizing element, and quarter wave plate) may be referred to as the near-eye side, and the second side may be referred to as the near-screen side.

In an exemplary embodiment, the optical system may further include a spacing element group disposed within the lens barrel, and the spacing element group may include at least a first spacing element that may be disposed between the first lens and the second lens and at least partially in contact with the second side of the first lens. In other examples, the set of spacer elements may further include a second spacer element, which may be disposed between the second lens and the third lens and at least partially in contact with the second side of the second lens. The reasonable use of the spacing element can effectively avoid the stray light risk, reduce the interference to the image quality, and further improve the imaging quality of the optical system.

In an exemplary embodiment, the first side of the reflective polarizing element may be bonded to the second side of the second lens, and the second side of the quarter-wave plate may be bonded to the first side of the third lens. By attaching the reflective polarizing element and the quarter-wave plate to the second side surface of the second lens and the first side surface of the third lens, respectively, the attaching difficulty of the reflective polarizing element and the quarter-wave plate can be reduced, and the attaching yield of the reflective polarizing element and the quarter-wave plate can be improved.

In an exemplary embodiment, the second side of the reflective polarizing element may be attached to the first side of the quarter-wave plate, and the second side of the quarter-wave plate may be attached to the first side of the third lens. The reflective polarizing element and the quarter-wave plate are attached together to form one film layer, so that the number of attached surfaces of the film layer can be reduced, and the attaching yield of the film layer can be improved.

In an exemplary embodiment, the optical system may further include a diaphragm, which may be disposed between the first side and the first lens. The eyes of the user can watch the image projected by the display screen at the position of the diaphragm, namely, the image light on the display screen is finally projected to the eyes of the user after being refracted and reflected for a plurality of times by the third lens, the quarter wave plate, the reflective polarizing element, the second lens, the first lens and the like.

In an exemplary embodiment, the first side or the second side of the third lens may be provided with a partially reflective layer. The partially reflective layer has a transflective effect on light. By plating the partially reflective layer on the first side or the second side of the third lens, the partially reflective layer can be far away from the reflective polarizing element, and the refractive length of the optical system can be increased.

In an exemplary embodiment, a light source may be provided on the display screen. The image light of the light source can be emitted from the display screen, sequentially passes through the third lens and the quarter-wave plate, reaches the reflective polarizing element, and is reflected at the reflective polarizing element to form first reflected image light. The first reflected image light passes through the quarter wave plate and reaches the partially reflective layer on the second side of the third lens, and then is reflected at the partially reflective layer to form second reflected image light. The second reflected image light passes through the third lens, the quarter-wave plate, the reflective polarizing element, the second lens, and the first lens in sequence to the diaphragm (i.e., the position where the user's eyes view the image). In other examples, image light exiting the display screen may pass through the third lens directly to the reflective polarizing element and then be reflected at the reflective polarizing element to form first reflected image light. The optical system provided by the application folds the required optical path on the premise of not influencing the projection quality in a light reflection and refraction combined mode, and the length of the optical system is effectively shortened.

In an exemplary embodiment, the inner diameter d0s of the first side end surface of the lens barrel, the interval EP01 of the first side end surface of the lens barrel and the first interval element along the optical axis, the radius of curvature R2 of the second side surface of the first lens, and the total effective focal length f of the optical system may satisfy: 10< d0s/EP01+|R2/f| <36. The application can restrict the surface shape of the first lens by limiting the ratio of the curvature radius of the second side surface of the first lens to the total effective focal length of the optical system within a certain range, thereby controlling the emergent angle of light rays at the first lens and improving the imaging quality of the optical system; meanwhile, the inner diameter of the first side end face of the lens barrel and the interval between the first side end face of the lens barrel and the first interval element along the optical axis are controlled in a matched mode, the thickness of a non-optical effective part of the first lens is limited, the machinability of the first lens is guaranteed, the optical system is more compact, and the miniaturization of the optical system is achieved.

In an exemplary embodiment, the radius of curvature R4 of the second side of the second lens, the radius of curvature R5 of the first side of the third lens, and the inner diameter d2s of the first side of the second spacer element may satisfy: -3< (R4+R5)/d 2s < -1 >. The correlation between the curvature radius of the second side surface of the second lens, the curvature radius of the first side surface of the third lens and the inner diameter of the first side surface of the second spacing element is reasonably controlled, so that the stability of the optical system can be effectively ensured.

In an exemplary embodiment, a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens, a spacing EP01 of the first side end surface of the lens barrel and the first spacing element along the optical axis, and a spacing EP12 of the first spacing element and the second spacing element along the optical axis may satisfy: 2.0< FG23/(EP 01+EP 12) <6.0. The combined focal length of the second lens, the reflective polarizing element, the quarter wave plate and the third lens, the mutual relation between the interval of the first side end face of the lens barrel and the interval of the first interval element and the interval of the second interval element along the optical axis and the interval of the first interval element and the second interval element along the optical axis are reasonably controlled, the thickness of the lens barrel can be limited, the compactness of the optical system is facilitated to be realized, the off-axis aberration of the optical system can be corrected, and the overall image quality of the optical system is improved.

In an exemplary embodiment, a length L of the lens barrel in a direction in which the optical axis is located, a center thickness CT1 of the first lens on the optical axis, and a center thickness CT2 of the second lens on the optical axis may satisfy: 3<L/(CT1+CT2) <5. By limiting the ratio of the length of the lens barrel in the direction of the optical axis to the sum of the center thicknesses of the first lens and the second lens within a certain range, the optical system can be made more compact, which is advantageous for realizing miniaturization of the optical system.

In an exemplary embodiment, the interval EP02 of the first side end surface of the lens barrel and the second interval element along the optical axis and the center thickness CT1 of the first lens on the optical axis may satisfy: 1.0< EP02/CT1<7.0. The mutual relation between the interval between the first side end surface of the lens barrel and the second interval element along the optical axis and the central thickness of the first lens on the optical axis is reasonably controlled, the maximum appearance of the lens barrel can be limited, the compactness of an optical system is facilitated, meanwhile, the off-axis aberration of the optical system can be corrected, and the overall image quality of the optical system is improved.

In an exemplary embodiment, a length L of the lens barrel in a direction in which the optical axis is located, a spacing EP02 of the first side end surface of the lens barrel and the second spacing element along the optical axis, and a relative F number Fno of the optical system may satisfy: 13< L/EP02×FNo <30. The length of the lens barrel in the direction of the optical axis, the interval between the first side end surface of the lens barrel and the second interval element along the optical axis and the relative F number of the optical system are reasonably controlled, the total effective focal length of the optical system can be indirectly controlled, and the optical system can meet the characteristic of large field angle.

In an exemplary embodiment, the inner diameter D0s of the first side end surface of the lens barrel, the outer diameter D0s of the first side end surface of the lens barrel, the radius of curvature R5 of the first side surface of the third lens, and the radius of curvature R6 of the second side surface of the third lens may satisfy: -53< (R5+R6)/|D0s-d0s| < 5.0. The inner diameter of the first side end surface of the lens barrel, the outer diameter of the first side end surface of the lens barrel, the mutual relation between the curvature radius of the first side surface of the third lens and the curvature radius of the second side surface of the third lens are reasonably controlled, the sensitivity of the third lens is reduced, the wall thickness size of the lens barrel can be effectively controlled on the premise of ensuring the optical performance of the optical system, and the balance of the compactness of the optical system and the processability of the lens barrel is realized.

In an exemplary embodiment, the abbe number V2 of the second lens, the refractive index N2 of the second lens, the total effective focal length f of the optical system, and the on-axis distance TD from the first side of the first lens to the second side of the third lens may satisfy: 11< (V2/N2) × (f/TD) <45. The abbe number of the second lens, the refractive index of the second lens, the total effective focal length of the optical system and the on-axis distance from the first side surface of the first lens to the second side surface of the third lens are reasonably controlled, so that aberration introduced by the third lens can be corrected, and the performance of the optical system is improved.

In an exemplary embodiment, the on-axis distance TD from the first side surface of the first lens to the second side surface of the third lens and the interval EP01 along the optical axis of the first side end surface of the lens barrel and the first interval element may satisfy: 3< TD/EP01<11. The axial distance between the first side surface of the first lens and the second side surface of the third lens and the mutual relation between the first side end surface of the lens barrel and the interval of the first interval element along the optical axis are reasonably controlled, so that the first lens and the third lens can keep the optimal relative position, the interval element has smaller thickness on the premise of ensuring that the interval element has proper strength, and the thickness of equipment using the optical system is reduced on the premise of ensuring that the optical system has a certain length.

In an exemplary embodiment, the inner diameter D1s of the first side surface of the first spacer element, the outer diameter D1s of the first side surface of the first spacer element, and the center thickness CT1 of the first lens on the optical axis may satisfy: 2< (D1 s-D1 s)/CT 1<15. The interrelationship between the internal diameter of the first side surface of the first interval element, the external diameter of the first side surface of the first interval element and the central thickness of the first lens on the optical axis is reasonably controlled, so that the assembly stability of the first lens is improved, stray light generated by the first lens is blocked, and the imaging quality of the optical system is improved.

In an exemplary embodiment, the interval P2m of the second spacer element and the second side end surface of the lens barrel along the optical axis, the center thickness CT2 of the second lens on the optical axis, and the air interval T23 of the second lens and the third lens along the optical axis may satisfy: 2< P2 m/(CT 2+ T23) <5. The space structure of the whole optical system can be rationalized by reasonably controlling the interval between the second interval element and the second side end face of the lens barrel along the optical axis, the central thickness of the second lens on the optical axis and the air interval between the second lens and the third lens along the optical axis, and the stability of the optical system is facilitated to be realized, thereby improving the performance of the optical system.

The optical system according to the above-described embodiment of the present application may employ a plurality of lenses and at least one spacer element, such as the three-lens and two spacer elements described above. By reasonably distributing the parameters of each lens and each interval element, the miniaturization of the optical system can be realized, the stray light phenomenon of the optical system is improved, and the processability, the assembly stability and the imaging quality of the optical system are improved. The optical system with the configuration has the characteristics of miniaturization, good assembly stability, less parasitic light, compact structure, good imaging quality and the like, and can well meet the use requirements of various portable electronic products in projection scenes.

In an embodiment of the present application, at least one of the mirrors of each of the first to third lenses is an aspherical mirror. The aspherical lens is characterized in that: the curvature varies continuously from the center of the lens to the periphery of the lens. 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 during imaging can be eliminated as much as possible, thereby improving imaging quality. Optionally, the first side and the second side of each of the first lens to the third lens are aspherical mirror surfaces.

However, those skilled in the art will appreciate that the number of lenses and spacing elements making up an optical system can be varied to achieve the various results and advantages described in this specification without departing from the scope of the application as claimed

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

First embodiment

An optical system according to a first embodiment of the present application is described below with reference to fig. 2 to 5C. Fig. 2 shows a schematic configuration diagram of an optical system 110 of example 1 according to a first embodiment of the present application; fig. 3 shows a schematic structural view of an optical system 120 of example 2 according to the first embodiment of the present application; fig. 4 shows a schematic configuration of an optical system 130 according to example 3 of the first embodiment of the present application.

As shown in fig. 2 to 4, each of the optical systems 110, 120, 130 includes a lens barrel, and a lens group and a spacing element group disposed in the lens barrel, the lens group including, in order from a first side (i.e., a human eye side) to a second side (i.e., a display screen side): a first lens E1, a second lens E2, and a third lens E3. Wherein, a reflective polarizing element RP and a quarter wave plate QWP are arranged between the second lens E2 and the third lens E3 in sequence. The near-screen side of the third lens E3 is provided with a partially reflective layer BS. The stop STO may be disposed between the human eye side and the first lens E1. The spacer element group includes: a first spacer element P1 and a second spacer element P2.

The first lens E1 has positive power, and its near-eye side S1 is convex and near-screen side S2 is convex. The second lens E2 has positive focal power, and its near-eye side S3 is concave and near-screen side S4 is convex. The near-eye side surface S9 of the third lens E3 is concave, and the near-screen side surface S10 is convex. The reflective polarizing element RP has a near-human eye side surface S5 (not shown) and a near-screen side surface S6 (not shown), and the near-human eye side surface S5 may be attached to the near-screen side surface S4 of the second lens E2. The quarter wave plate QWP has a near-human eye side S7 (not shown) and a near-screen side S8 (not shown), the near-screen side S8 of which is attachable to the near-human eye side S9 of the third lens E3. A near-eye side S11 (not shown) of the partially reflective layer BS may be attached to a near-screen side S10 of the third lens E3.

In this example, a light source may be provided on the display screen S12. After the image light from the display screen S12 sequentially passes through the third lens E3, the quarter-wave plate QWP and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected once passes through the quarter-wave plate QWP and reaches the partially reflective layer BS on the near-screen side of the third lens E3, a second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the third lens E3, the quarter wave plate QWP, the reflective polarizing element RP, the second lens E2, the first lens E1, and finally, the target object (not shown) in the projection space in this order. For example, the light reflected by the optical system twice is finally projected into eyes of a user.

Table 1 shows a basic parameter table of the optical system of the first embodiment, in which the unit of curvature radius, thickness/distance is millimeter (mm). The image light from the display screen S12 passes through the elements in the order of number 15 to number 1 and is finally projected into a target object in space such as human eyes.

TABLE 1

In the present embodiment, the value of the total effective focal length f of the optical system is 26.63mm, and the value of the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens is 28.64mm.

In the first embodiment, the near-eye side surface S1 and the near-screen side surface S2 of the first lens E1, the near-eye side surface S3 and the near-screen side surface S4 of the second lens E2, and the near-eye side surface S9 and the near-screen side surface S10 of the third lens E3 are all aspheric, and the surface shape z of each aspheric lens can be defined by, but not limited to, the following aspheric formula:

wherein z is the depth of the aspheric surface (the point on the aspheric surface at a distance y from the optical axis, and the tangential plane tangential to the vertex on the optical axis of the aspheric surface, the perpendicular distance between the two); c is the curvature of the apex of the aspheric surface; k is the coefficient of the conical surface,is the radial distance; u is r/r _n ；r _n Is normalized radius; a, a _m Is the mth order Q ^con Coefficients; q (Q) _m ^con Is the mth order Q ^con A polynomial. Table 2 shows polynomial coefficients a that can be used for each of the aspherical mirrors S1, S2, S3, S4, S9 and S10 in the first embodiment ₀ 、a ₁ 、a ₂ And a ₃ 。

Face number	a0	a1	a2	a3
					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
					S9	4.1356E-02	3.2488E-02	2.2439E-01	-7.4613E-02
S10	2.3923E-01	4.9481E-02	8.8259E-03	-6.1318E-03

TABLE 2

The optical systems 110, 120, and 130 in examples 1, 2, and 3 of the first embodiment are different in the structural dimensions of the lens barrel and the spacer element included. Table 3 shows some basic parameters of the lens barrels, the spacing elements of the optical systems 110, 120 and 130 of the first embodiment, such as D1s, D2s, D0s, EP01, EP12, EP02, P2m and L, etc., and some of the basic parameters listed in table 3 are measured according to the labeling method shown in fig. 1, and the basic parameters listed in table 3 are all in millimeters (mm).

TABLE 3 Table 3

Fig. 5A shows on-axis chromatic aberration curves of the optical systems 110, 120, and 130 of the first embodiment, which represent the convergent focus deviation of light rays of different wavelengths after passing through the optical systems 110, 120, and 130. Fig. 5B shows astigmatism curves of the optical systems 110, 120, and 130 of the first embodiment, which represent meridional image surface curvature and sagittal image surface curvature corresponding to different image heights. Fig. 5C shows distortion curves of the optical systems 110, 120, and 130 of the first embodiment, which represent distortion magnitude values corresponding to different image heights. As can be seen from fig. 5A to 5C, the optical systems 110, 120, and 130 according to the first embodiment can achieve good imaging quality.

Second embodiment

An optical system according to a second embodiment of the present application is described below with reference to fig. 6 to 9C. Fig. 6 shows a schematic structural diagram of an optical system 210 of example 1 according to a second embodiment of the present application; fig. 7 shows a schematic structural diagram of an optical system 220 of example 2 according to a second embodiment of the present application; fig. 8 shows a schematic structural diagram of an optical system 230 according to example 3 of the second embodiment of the present application.

As shown in fig. 6 to 8, each of the optical systems 210, 220, 230 includes a lens barrel, and a lens group and a spacing element group disposed in the lens barrel, the lens group including, in order from a first side (i.e., a human eye side) to a second side (i.e., a display screen side): a first lens E1, a second lens E2, and a third lens E3. Wherein, a reflective polarizing element RP and a quarter wave plate QWP are arranged between the second lens E2 and the third lens E3 in sequence. The near-screen side of the third lens E3 is provided with a partially reflective layer BS. The stop STO may be disposed between the human eye side and the first lens E1. The spacer element group includes: a first spacer element P1 and a second spacer element P2.

The first lens E1 has positive power, and its near-eye side S1 is convex and near-screen side S2 is convex. The second lens E2 has negative focal power, and its near-eye side S3 is concave and near-screen side S4 is convex. The third lens E3 has positive power, and its near-eye side surface S9 is concave and near-screen side surface S10 is convex. The reflective polarizing element RP has a near-human eye side surface S5 (not shown) and a near-screen side surface S6 (not shown), and the near-human eye side surface S5 may be attached to the near-screen side surface S4 of the second lens E2. The quarter wave plate QWP has a near-human eye side S7 (not shown) and a near-screen side S8 (not shown), the near-screen side S8 of which is attachable to the near-human eye side S9 of the third lens E3. A near-eye side S11 (not shown) of the partially reflective layer BS may be attached to a near-screen side S10 of the third lens E3.

Table 4 shows a basic parameter table of the optical system of the second embodiment, in which the unit of curvature radius, thickness/distance is millimeter (mm). The image light from the display screen S12 passes through the elements in the order of number 15 to number 1 and is finally projected into a target object in space such as human eyes.

TABLE 4 Table 4

In the present embodiment, the value of the total effective focal length f of the optical system is 28.45mm, and the value of the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens is 33.73mm.

In the second embodiment, the near-human eye side surface S1 and the near-screen side surface S2 of the first lens E1, the near-human eye side surface S3 and the near-screen side surface S4 of the second lens E2, and the near-human eye side surface S9 and the near-screen side surface S10 of the third lens E3 are aspherical surfaces. Table 5 shows polynomial coefficients a that can be used for each of the aspherical mirrors S1, S2, S3, S4, S9 and S10 in the second embodiment ₀ 、a ₁ 、a ₂ And a ₃ 。

Face number	a0	a1	a2	a3
					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
					S9	2.6607E-01	6.6022E-02	3.5223E-02	4.8705E-02
S10	-7.4565E-02	1.0880E-01	7.9410E-03	-3.7533E-04

TABLE 5

The optical systems 210, 220, and 230 in examples 1, 2, and 3 of the second embodiment are different in the structural dimensions of the lens barrel and the spacer element included. Table 6 shows some basic parameters of the lens barrels, the spacing elements of the optical systems 210, 220 and 230 of the second embodiment, such as D1s, D2s, D0s, EP01, EP12, EP02, P2m and L, etc., and some of the basic parameters listed in table 6 are measured according to the labeling method shown in fig. 1, and the basic parameters listed in table 6 are all in millimeters (mm).

Examples/parameters	d1s	D1s	d2s	d0s	D0s	EP01	EP12	EP02	P2m	L
											2-1	60.88	75.08	64.05	63.88	78.05	6.71	3.14	13.87	18.9	32.77
2-2	60.88	75.08	61	62.74	78.65	7.48	4.34	12.01	19.47	31.48
											2-3	60.88	80.08	61	83.11	85.8	4.48	4.34	9.02	20.4	29.42

TABLE 6

Fig. 9A shows on-axis chromatic aberration curves of the optical systems 210, 220, and 230 of the second embodiment, which represent the convergent focus deviation of light rays of different wavelengths after passing through the optical systems 210, 220, and 230. Fig. 9B shows astigmatism curves of the optical systems 210, 220, and 230 of the second embodiment, which represent meridional image surface curvature and sagittal image surface curvature corresponding to different image heights. Fig. 9C shows distortion curves of the optical systems 210, 220, and 230 of the second embodiment, which represent distortion magnitude values corresponding to different image heights. As can be seen from fig. 9A to 9C, the optical systems 210, 220, and 230 according to the second embodiment can achieve good imaging quality.

Third embodiment

An optical system according to a third embodiment of the present application is described below with reference to fig. 10 to 13C. Fig. 10 shows a schematic structural view of an optical system 310 of example 1 according to a third embodiment of the present application; fig. 11 shows a schematic structural view of an optical system 320 according to example 2 of the third embodiment of the present application; fig. 12 shows a schematic configuration of an optical system 330 according to example 3 of the third embodiment of the present application.

As shown in fig. 10 to 12, each of the optical systems 310, 320, 330 includes a lens barrel, and a lens group and a spacing element group disposed in the lens barrel, the lens group including, in order from a first side (i.e., a human eye side) to a second side (i.e., a display screen side): a first lens E1, a second lens E2, and a third lens E3. Wherein, a reflective polarizing element RP and a quarter wave plate QWP are arranged between the second lens E2 and the third lens E3 in sequence. The near-screen side of the third lens E3 is provided with a partially reflective layer BS. The stop STO may be disposed between the human eye side and the first lens E1. The spacer element group includes: a first spacer element P1 and a second spacer element P2.

The first lens E1 has negative focal power, and its near-eye side S1 is concave and its near-screen side S2 is concave. The second lens E2 has positive optical power, and its near-eye side S3 is convex and its near-screen side S4 is convex. The third lens E3 has positive power, and its near-eye side surface S9 is concave and near-screen side surface S10 is convex. The reflective polarizing element RP has a near-human eye side surface S5 (not shown) and a near-screen side surface S6 (not shown). The quarter wave plate QWP has a near-eye side S7 (not shown) and a near-screen side S8 (not shown). The near-screen side S6 of the reflective polarizer RP may be bonded to the near-eye side S7 of the quarter-wave plate QWP. The near-screen side S8 of the quarter wave plate QWP may be attached to the near-eye side S9 of the third lens E3. A near-eye side S11 (not shown) of the partially reflective layer BS may be attached to a near-screen side S10 of the third lens E3.

In this example, a light source may be provided on the display screen S12. After the image light from the display screen S12 sequentially passes through the third lens E3 and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected once passes through the quarter-wave plate QWP and reaches the partially reflective layer BS on the near-screen side of the third lens E3, a second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the third lens E3, the quarter wave plate QWP, the reflective polarizing element RP, the second lens E2, the first lens E1, and finally, the target object (not shown) in the projection space in this order. For example, the light reflected by the optical system twice is finally projected into eyes of a user.

Table 7 shows a basic parameter table of the optical system of the third embodiment, in which the unit of curvature radius, thickness/distance is millimeter (mm). The image light from the display screen S12 passes through the elements in the order of number 13 to number 1 and is finally projected into a target object in space such as human eyes.

TABLE 7

In the present embodiment, the value of the total effective focal length f of the optical system is 29.87mm, and the value of the combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens is 28.81mm.

In the third embodiment, the near-human eye side surface S1 and the near-screen side surface S2 of the first lens E1, the near-human eye side surface S3 and the near-screen side surface S4 of the second lens E2, and the near-human eye side surface S9 and the near-screen side surface S10 of the third lens E3 are aspherical surfaces. Table 8 shows the aspherical mirror surfaces S1, S2, S3, S4 which can be used in the third embodimentPolynomial coefficients a of S9 and S10 ₀ 、a ₁ 、a ₂ And a ₃ 。

Face number	a0	a1	a2	a3
					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
					S9	2.8672E-01	-2.9025E-03	2.8759E-03	-8.1075E-04
S10	1.1272E-01	-9.1425E-04	-3.7528E-03	-8.9808E-05

TABLE 8

The optical systems 310, 320, and 330 in examples 1, 2, and 3 of the third embodiment are different in the structural dimensions of the lens barrel and the spacer element included. Table 9 shows some basic parameters of the lens barrels, the spacing elements, such as D1s, D2s, D0s, EP01, EP12, EP02, P2m, and L, etc., of the optical systems 310, 320, and 330 of the third embodiment, some of the basic parameters listed in table 9 are measured according to the labeling method shown in fig. 1, and the basic parameters listed in table 9 are all in millimeters (mm).

Examples/parameters	d1s	D1s	d2s	d0s	D0s	EP01	EP12	EP02	P2m	L
											3-1	54.56	80.07	64.54	69.07	84.08	6.86	3.09	10.15	22.33	32.48
3-2	54.56	81.07	67.65	69.87	84.04	8.71	4.09	12.99	21.09	34.08
											3-3	54.56	84.07	67.65	86.16	89.25	5.36	4.09	9.65	21.78	31.43

TABLE 9

Fig. 13A shows on-axis chromatic aberration curves of the optical systems 310, 320, and 330 of the third embodiment, which represent the convergent focus deviation of light rays of different wavelengths after passing through the optical systems 310, 320, and 330. Fig. 13B shows astigmatism curves of the optical systems 310, 320, and 330 of the third embodiment, which represent meridional image surface curvature and sagittal image surface curvature corresponding to different image heights. Fig. 13C shows distortion curves of the optical systems 310, 320, and 330 of the third embodiment, which represent distortion magnitude values corresponding to different image heights. As can be seen from fig. 13A to 13C, the optical systems 310, 320, and 330 according to the third embodiment can achieve good imaging quality.

In summary, table 10 shows the values of the conditional expressions of the examples in the first to third embodiments.

Condition/example	1-1	1-2	1-3	2-1	2-2	2-3	3-1	3-2	3-3
										d0s/EP01+\|R2/f\|	16.20	16.20	35.06	11.71	10.58	20.74	15.79	13.74	21.79
(R4+R5)/d2s	-1.30	-1.30	-1.30	-2.39	-2.51	-2.51	-2.38	-2.27	-2.27
										FG23/(EP01+EP12)	3.33	3.33	5.45	3.42	2.85	3.82	2.89	2.25	3.05
L/(CT1+CT2)	4.50	4.43	4.04	3.89	3.74	3.49	3.24	3.40	3.13
										(R5+R6)/\|D0s-d0s\|	-5.08	-5.08	-23.32	-9.75	-8.68	-51.36	-8.80	-9.32	-42.75
(V2/N2)×(f/TD)	35.86	35.86	35.86	12.13	12.13	12.13	44.74	44.74	44.74
										TD/EP01	4.53	4.53	10.35	3.98	3.57	5.96	4.08	3.21	5.22
(D1s-d1s)/CT1	4.40	4.03	5.12	2.15	2.15	2.90	12.31	12.79	14.24
										EP02/CT1	2.48	2.48	1.54	2.10	1.81	1.36	4.90	6.27	4.66
P2m/(CT2+T23)	3.82	3.74	3.81	4.29	4.41	4.63	2.35	2.22	2.29
										L/EP02×Fno	20.41	20.11	29.61	13.44	14.91	18.56	19.17	15.72	19.51

Table 10

The above description is only illustrative of the preferred embodiments of the present utility model and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the utility model referred to in the present utility model is not limited to the specific combinations of the technical features described above, but also covers other technical features formed by any combination of the technical features described above or their equivalents without departing from the inventive concept. Such as the above-mentioned features and the technical features disclosed in the present utility model (but not limited to) having similar functions are replaced with each other.

Claims

1. An optical system, comprising:

the lens group comprises a first lens, a second lens and a third lens which are sequentially arranged from a first side to a second side along an optical axis, wherein a reflective polarizing element and a quarter wave plate are sequentially arranged between the second lens and the third lens;

a spacer element group including a first spacer element disposed between the first lens and the second lens and in contact with a second side of the first lens; and

A lens barrel in which the lens group and the spacing element group are disposed,

wherein an inner diameter d0s of the first side end surface of the lens barrel, an interval EP01 of the first side end surface of the lens barrel and the first interval element along the optical axis, a curvature radius R2 of the second side surface of the first lens, and a total effective focal length f of the optical system satisfy: 10< d0s/EP01+|R2/f| <36.

2. The optical system of claim 1, wherein the first side or the second side of the third lens is provided with a partially reflective layer.

3. The optical system of claim 1, wherein the first side of the reflective polarizing element is attached to the second side of the second lens and the second side of the quarter-wave plate is attached to the first side of the third lens.

4. The optical system of claim 1, wherein the second side of the reflective polarizing element is attached to the first side of the quarter-wave plate and the second side of the quarter-wave plate is attached to the first side of the third lens.

5. The optical system of claim 1, wherein the set of spacer elements further comprises a second spacer element disposed between the second lens and the third lens and in contact with a second side of the second lens,

Wherein a radius of curvature R4 of the second side of the second lens, a radius of curvature R5 of the first side of the third lens and an inner diameter d2s of the first side of the second spacer element satisfy: -3< (R4+R5)/d 2s < -1 >.

6. The optical system of claim 1, wherein the set of spacer elements further comprises a second spacer element disposed between the second lens and the third lens and in contact with a second side of the second lens,

wherein a combined focal length FG23 of the second lens, the reflective polarizing element, the quarter-wave plate, and the third lens, a spacing EP01 of the first side end face of the lens barrel and the first spacing element along the optical axis, and a spacing EP12 of the first spacing element and the second spacing element along the optical axis satisfy: 2.0< FG23/(EP 01+EP 12) <6.0.

7. The optical system according to claim 1, wherein a length L of the lens barrel in a direction in which the optical axis is located, a center thickness CT1 of the first lens on the optical axis, and a center thickness CT2 of the second lens on the optical axis satisfy: 3<L/(CT1+CT2) <5.

8. The optical system of any of claims 1-7, wherein the set of spacer elements further comprises a second spacer element disposed between the second lens and the third lens and in contact with a second side of the second lens,

Wherein, the interval EP02 between the first side end face of the lens barrel and the second interval element along the optical axis and the central thickness CT1 of the first lens on the optical axis satisfy the following conditions: 1.0< EP02/CT1<7.0.

9. The optical system of any of claims 1-7, wherein the set of spacer elements further comprises a second spacer element disposed between the second lens and the third lens and in contact with a second side of the second lens,

wherein, the length L of the lens barrel in the direction of the optical axis, the interval EP02 of the first side end surface of the lens barrel and the second interval element along the optical axis and the relative F number FNo of the optical system satisfy the following conditions: 13< L/EP02×FNo <30.

10. The optical system according to any one of claims 1 to 7, wherein an inner diameter D0s of the first side end surface of the lens barrel, an outer diameter D0s of the first side end surface of the lens barrel, a radius of curvature R5 of the first side surface of the third lens, and a radius of curvature R6 of the second side surface of the third lens satisfy: -53< (R5+R6)/|D0s-d0s| < 5.0.

11. The optical system of any one of claims 1-7, wherein an abbe number V2 of the second lens, a refractive index N2 of the second lens, a total effective focal length f of the optical system, and an on-axis distance TD from the first side of the first lens to the second side of the third lens satisfy: 11< (V2/N2) × (f/TD) <45.

12. The optical system according to any one of claims 1 to 7, wherein an on-axis distance TD from the first side surface of the first lens to the second side surface of the third lens and a spacing EP01 of the first side end surface of the lens barrel and the first spacing element along the optical axis satisfy: 3< TD/EP01<11.

13. The optical system according to any one of claims 1 to 7, wherein an inner diameter D1s of the first side surface of the first spacer element, an outer diameter D1s of the first side surface of the first spacer element, and a center thickness CT1 of the first lens on the optical axis satisfy: 2< (D1 s-D1 s)/CT 1<15.

14. The optical system of any of claims 1-7, wherein the set of spacer elements further comprises a second spacer element disposed between the second lens and the third lens and in contact with a second side of the second lens,

wherein, the interval P2m of the second interval element and the second side end surface of the lens barrel along the optical axis, the center thickness CT2 of the second lens on the optical axis and the air interval T23 of the second lens and the third lens along the optical axis satisfy: 2< P2 m/(CT 2+ T23) <5.