CN116400485A - Optical system and optical apparatus including the same - Google Patents

Optical system and optical apparatus including the same Download PDF

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Publication number
CN116400485A
CN116400485A CN202310496640.5A CN202310496640A CN116400485A CN 116400485 A CN116400485 A CN 116400485A CN 202310496640 A CN202310496640 A CN 202310496640A CN 116400485 A CN116400485 A CN 116400485A
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China
Prior art keywords
lens
optical system
wave plate
quarter wave
optical axis
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CN202310496640.5A
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Chinese (zh)
Inventor
戴付建
张晓彬
金银芳
赵烈烽
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Zhejiang Sunny Optics Co Ltd
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Zhejiang Sunny Optics Co Ltd
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Priority to CN202310496640.5A priority Critical patent/CN116400485A/en
Publication of CN116400485A publication Critical patent/CN116400485A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0015—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design
    • G02B13/002—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface
    • G02B13/0035—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras characterised by the lens design having at least one aspherical surface having three lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/001—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras
    • G02B13/0055—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element
    • G02B13/0065—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras employing a special optical element having a beam-folding prism or mirror
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/18—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical projection, e.g. combination of mirror and condenser and objective
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/286—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/02—Mountings, adjusting means, or light-tight connections, for optical elements for lenses
    • G02B7/021—Mountings, adjusting means, or light-tight connections, for optical elements for lenses for more than one lens

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

The application discloses an optical system, this optical system includes in order along the optical axis from first side to second side: the first lens group, the second lens and the third lens, wherein the first lens group sequentially comprises from a first side to a second side: the second side surface of the reflective polarizing element is attached to the first side surface of the quarter wave plate, and the second side surface of the quarter wave plate is attached to the first side surface of the first lens; a partial reflection layer is arranged on at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens; the first side surface of the first lens is a concave surface, and the second side surface is a convex surface; the second side surface of the second lens is a convex surface; and the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens satisfy: 0< R1/R4<2.

Description

Optical system and optical apparatus including the same
Technical Field
The present application relates to the field of optical elements, and more particularly, to an optical system and an optical apparatus including the same.
Background
2022 is one year of rapid development of AR/VR devices, in which several companies enter the AR/VR domain, and multiple areas lay out the AR/VR industry chain; in the AR/VR domain, competition is becoming more and more intense, especially in the VR domain.
Currently, VR architecture is becoming mature, and devices employing one-piece and two-piece refractive-reflective optical system architecture are increasing and becoming increasingly manufactured. To maintain competitiveness, many enterprises have laid out three-piece catadioptric optical system architectures. However, from the viewpoint of user experience, the body of the catadioptric optical system is long, and when the catadioptric optical system is used, the gravity center is positioned forward, the experience is poor, and improvement is urgently needed. In addition, the imaging quality of the refraction-reflection optical system is still to be improved, and the problems of fuzzy external vision field pictures and the like exist, so that the experience effect of a user is affected.
Disclosure of Invention
The application provides an optical system, the optical system includes in order from first side to second side along the optical axis: the first lens group, the second lens and the third lens, wherein the first lens group sequentially comprises from a first side to a second side: the second side surface of the reflective polarizing element is attached to the first side surface of the quarter wave plate, and the second side surface of the quarter wave plate is attached to the first side surface of the first lens; a partial reflection layer is arranged on at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens; the first side surface of the first lens is a concave surface, and the second side surface is a convex surface; the second side surface of the second lens is a convex surface; and the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens satisfy: 0< R1/R4<2.
In one embodiment, the center thickness CT1 of the first lens on the optical axis, the distance TD between the first side surface of the first lens and the second side surface of the third lens on the optical axis satisfies: 0< CT1/TD <0.6.
In one embodiment, the abbe number V1 of the first lens, the abbe number V2 of the second lens, the abbe number V3 of the third lens, the abbe number VRP of the reflective polarizing element, and the abbe number VQWP of the quarter wave plate satisfy: 30< (v1+v2+v3)/3 < vrp and 30< (v1+v2+v3)/3 < vqwp.
In one embodiment, the distance Tr1rBS on the optical axis from the first side of the first lens to the surface of the lens where the partially reflective layer is located and the distance TD on the optical axis from the first side of the first lens to the second side of the third lens satisfy: 0.3< Tr1rBS/TD <0.7.
In one embodiment, the radius of curvature R1 of the first side of the first lens, the central thickness CTRP of the reflective polarizing element on the optical axis, and the central thickness CTQWP of the quarter wave plate on the optical axis satisfy: -310< R1/(CTRP+CTQWP) < -40.
In one embodiment, the sum Σat of the effective focal length f of the optical system, the distance between the first lens group and the second lens on the optical axis, and the distance between the second lens and the third lens on the optical axis satisfies: 8<f/Σat <150.
In one embodiment, the effective radius DT11 of the first side of the first lens, the distance TD on the optical axis between the first side of the first lens and the second side of the third lens, satisfies: 0.6< DT11/TD <1.8.
In one embodiment, the radius of curvature R1 of the first side of the first lens, the radius of curvature RBS of the surface of the lens on which the partially reflective layer is located, and the effective focal length f of the optical system satisfy: -7.0< (r1+rbs)/f < -1.5.
In one embodiment, the radius of curvature R1 of the first side of the first lens and the effective focal length f of the optical system satisfy: -5< R1/f < -0.7.
In one embodiment, a distance SAG11 between an intersection point of the first side surface of the first lens on the optical axis and a vertex of a maximum effective radius of the first side surface of the first lens on the optical axis, a center thickness CT1 of the first lens on the optical axis, and an f-number Fno of the optical system satisfy: 8< SAG11/CT1 XFNo < -4.
In one embodiment, the distance SAG22 on the optical axis from the intersection of the second side of the second lens on the optical axis to the maximum effective radius vertex of the second side of the second lens satisfies the curvature radius R4 of the second side of the second lens: 0< SAG22/R4<40.5.
In one embodiment, the sum Σct of the effective focal length f of the optical system, the maximum field angle FOV of the optical system, the reflective polarizing element, the quarter wave plate, the center thicknesses of the first lens, the second lens, and the third lens on the optical axis satisfies: 1.5< f×tan (FOV/2)/ΣCT <3.5.
In one embodiment, the first lens group has positive power, the second lens has positive power, the third lens has negative power and the first side thereof is concave.
In one embodiment, the effective focal length F1 of the first lens group and the effective focal length F of the optical system satisfy: 0.8< F1/f <1.2.
In one embodiment, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, and the center thickness CT3 of the third lens on the optical axis satisfy: the ratio of (CT 1+ CT 2)/CT 3 is less than or equal to 5 and less than 11.
In one embodiment, the third lens has positive optical power and its second side is convex.
In one embodiment, the center thickness CT3 of the third lens on the optical axis, the effective focal length f of the optical system, and the maximum field angle FOV of the optical system satisfy: 0.2< CT3/(f×tan (FOV/2)) <0.5.
In one embodiment, the radius of curvature R6 of the second side of the third lens and the effective focal length f3 of the third lens satisfy: -1.1< R6/f3< -0.1.
In one embodiment, the first lens has an abbe number V1, the second lens has an abbe number V2, the optical system has an effective focal length F, and the first lens group has an effective focal length F1 that satisfies: 2< (V1-V2) ×f/F1<5.
In another aspect, the present application also provides an optical apparatus including the optical system provided in at least one of the foregoing embodiments.
The optical system provided by the application is a three-piece type refraction and reflection optical system, and the folding effect of an imaging light path is realized by utilizing the additional function of a quarter wave plate on the polarized light phase, the light splitting function of a reflective polarizing element and the reflection function of a partial reflection layer, so that the height of the body can be better compressed, and the imaging quality is improved. Meanwhile, the surface type and the curvature radius of the lens are reasonably set, the first side surface of the first lens is a concave surface, the second side surface of the first lens is a convex surface, the second side surface of the second lens is a convex surface, and the curvature radius R1 of the first side surface of the first lens and the curvature radius R4 of the second side surface of the second lens meet the following conditions: and 0< R1/R4<2, which is favorable for reducing the included angle between light rays and the surface of the lens and reducing aberration, thereby improving the system performance.
Drawings
Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:
FIG. 1 shows a schematic diagram of a structural layout of an optical system and optical path foldback according to the present application;
Fig. 2 shows a schematic structural view of an optical system according to embodiment 1 of the present application;
fig. 3A to 3C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve, respectively, of the optical system according to embodiment 1 of the present application;
fig. 4 shows a schematic structural view of an optical system according to embodiment 2 of the present application;
fig. 5A to 5C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 2 of the present application, respectively;
fig. 6 shows a schematic structural view of an optical system according to embodiment 3 of the present application;
fig. 7A to 7C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 3 of the present application, respectively;
fig. 8 shows a schematic structural view of an optical system according to embodiment 4 of the present application;
fig. 9A to 9C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 4 of the present application, respectively;
fig. 10 shows a schematic structural view of an optical system according to embodiment 5 of the present application;
fig. 11A to 11C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 5 of the present application, respectively;
fig. 12 shows a schematic structural view of an optical system according to embodiment 6 of the present application; and
Fig. 13A to 13C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 6 of the present application, respectively.
Detailed Description
For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of exemplary embodiments of the application and are not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in this specification, the expressions first, second, etc. are only used to distinguish one feature from another feature, and do not represent any limitation of the feature. Accordingly, a first lens discussed below may also be referred to as a second lens, and a second lens may also be referred to as a first lens, without departing from the teachings of the present application.
In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.
Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.
It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the present application, use of "may" means "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The features, principles and other aspects of the present application are described in detail below with reference to the accompanying drawings and in connection with the embodiments.
The optical system according to an exemplary embodiment of the present application includes, in order from a first side to a second side along an optical axis: the first lens group, the second lens and the third lens, wherein the first lens group sequentially comprises from a first side to a second side: the second side surface of the reflective polarizing element is attached to the first side surface of the quarter wave plate, and the second side surface of the quarter wave plate is attached to the first side surface of the first lens; at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens is provided with a partial reflection layer. The reflection type polarizer and the quarter wave plate are attached to the first side face of the first lens, so that the polarization state of polarized light can be changed, light rays are reflected when passing through the first side face of the first lens for the first time, and light rays are transmitted when passing through the first side face of the first lens for the second time; at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens is provided with a partial reflection layer, and the optical path can be folded and the length of the optical system can be compressed by combining the polarizing film on the first side surface of the first lens.
The optical system provided by the application is a three-piece type refraction and reflection optical system, and the folding effect of an imaging light path is realized by utilizing the additional function of a quarter wave plate on the polarized light phase, the light splitting function of a reflective polarizing element and the reflection function of a partial reflection layer, so that the height of the body can be better compressed, and the imaging quality is improved.
In an exemplary embodiment, the first side of the first lens is concave and the second side is convex.
In an exemplary embodiment, the second side of the second lens is convex.
In an exemplary embodiment, the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens satisfy: 0< R1/R4<2.
The optical system according to an exemplary embodiment of the present application includes, in order from a first side to a second side along an optical axis: the first lens group, the second lens and the third lens, wherein the first lens group sequentially comprises from a first side to a second side: the second side surface of the reflective polarizing element is attached to the first side surface of the quarter wave plate, and the second side surface of the quarter wave plate is attached to the first side surface of the first lens; a partial reflection layer is arranged on at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens; the first side surface of the first lens is a concave surface, and the second side surface is a convex surface; the second side surface of the second lens is a convex surface; and the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens satisfy: 0< R1/R4<2. The polarization state of polarized light can be changed by attaching the reflective polarizer and the quarter wave plate on the first side surface of the first lens, so that light rays are reflected when passing through the first side surface of the first lens for the first time and transmitted when passing through the first side surface of the first lens for the second time; at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens is provided with a partial reflection layer, and the optical path can be folded and the length of the optical system can be compressed by combining the polarizing film on the first side surface of the first lens. Meanwhile, the surface types and the curvature radiuses of the first lens and the second lens are reasonably set, the first side face of the first lens is a concave face, the second side face of the first lens is a convex face, the second side face of the second lens is a convex face, and the shape of the lens is as above, so that the included angle between light rays and the surface of the lens is reduced, aberration is reduced, and system performance is improved.
In an exemplary embodiment, the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens may further satisfy: 0.5< R1/R4<2.
In an exemplary embodiment, the optical system further includes a display disposed on a second side of the third lens, where the optical system is applicable to, for example, a VR device, and the first side may be, for example, a human eye side, and the second side may be, for example, a display side, and image light on a display screen is finally projected to an eye of a user after being refracted and reflected multiple times by the third lens, the second lens, the first lens, the quarter wave plate, the reflective polarizing element, and the like.
Referring to fig. 1, the optical system sequentially includes, from the first side to the second side in the optical axis direction, a stop STO, a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3, and a display S9. The reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8.
In an exemplary embodiment, the optical system further includes a partially reflective layer disposed on at least one of the second side of the first lens, the first side of the second lens, and the second side. The partial reflection layer has a semi-transmission and semi-reflection function. In some embodiments, as shown in fig. 2 and 4, the second side of the first lens is provided with a partially reflective layer, and light emitted from the display screen sequentially passes through the third lens, the second lens, the first lens, the quarter wave plate QWP, reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens again, and then the light beam is reflected again at the partially reflective layer on the second side of the first lens and passes through the first lens, the quarter wave plate QWP, the reflective polarizing element RP in order, passes through the aperture STO, and finally exits toward the eye side. In other embodiments, as shown in fig. 6, 8, 10 and 12, a partially reflective layer is disposed on the second side of the second lens, and light emitted from the display screen sequentially passes through the third lens, the second lens, the first lens, the quarter wave plate QWP, reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP, the first lens, reaches the second lens again, and then the light beam is reflected again at the partially reflective layer on the second side of the second lens and passes through the second lens, the first lens, the quarter wave plate QWP, the reflective polarizing element RP in order, passes through the aperture stop, and finally exits toward the human eye side.
In an exemplary embodiment, the reflective polarizing element and the quarter wave plate are combined, and a required structure can be obtained through one-time attaching procedure operation instead of two-time attaching, so that the angle position error caused by attaching is reduced, and the imaging quality is improved.
The optical system according to the exemplary embodiment of the present application can reflect light of a certain polarization direction while transmitting light orthogonal to the polarization direction by providing the reflective polarizing element; the polarization state of the light can be changed by arranging a quarter wave plate; the reflection and transmission can be realized through the partial reflection layer arranged on at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens, the refraction and reflection of the system light path can be realized, and the length of the VR device can be shortened.
In an exemplary embodiment, the optical system of the present application may satisfy: 0< CT1/TD <0.6, wherein CT1 is the center thickness of the first lens on the optical axis, and TD is the distance from the first side surface of the first lens to the second side surface of the third lens on the optical axis. Satisfies 0< CT1/TD <0.6, ensures the structural strength of the first lens by controlling the ratio of the center thickness of the first lens to the axial distance from the first lens to the third lens, and is beneficial to the assembly of an optical system.
In an exemplary embodiment, the optical system of the present application may satisfy: 30< (v1+v2+v3)/3 < vrpand 30< (v1+v2+v3)/3 < VQWP, where V1 is the dispersion coefficient of the first lens, V2 is the dispersion coefficient of the second lens, V3 is the dispersion coefficient of the third lens, VRP is the dispersion coefficient of the reflective polarizing element, VQWP is the dispersion coefficient of the quarter wave plate. The dispersion coefficients of the three lenses and the dispersion coefficients of the reflective polarizing element and the quarter wave plate are controlled to be larger, and accordingly, the refractive index is smaller, so that the influence on an optical system when the thickness of the reflective polarizing element and the quarter wave plate is changed is reduced.
In an exemplary embodiment, the optical system of the present application may satisfy: 0.3< Tr1rBS/TD <0.7, where Tr1rBS is a distance on the optical axis between the first side of the first lens and the surface of the lens where the partially reflective layer is located, and TD is a distance on the optical axis between the first side of the first lens and the second side of the third lens. Satisfying 0.3< Tr1rBS/TD <0.7, the ratio is larger by controlling the axial distance from the first side surface of the first lens to the surface of the lens where the partial reflecting layer is positioned and the axial distance from the first side surface of the first lens to the second side surface of the third lens, so that the light refraction is longer, and the length of the optical system is favorable to be shortened.
In an exemplary embodiment, the optical system of the present application may satisfy the condition-310 < R1/(ctrp+ctqwp) < -40, where R1 is a radius of curvature of the first side of the first lens, CTRP is a center thickness of the reflective polarizing element on the optical axis, and CTQWP is a center thickness of the quarter wave plate on the optical axis. Satisfies-310 < R1/(CTRP+CTQWP) < -40, and the ratio is larger by controlling the sum of the curvature radius of the first side surface of the first lens and the center thicknesses of the reflective polarizing element and the quarter wave plate, thereby being beneficial to controlling the bending degree of the first side surface of the first lens and further beneficial to the curved surface attaching degree of the reflective polarizing element and the quarter wave plate.
In an exemplary embodiment, the optical system of the present application may satisfy: 8<f/Σat <150, where f is the effective focal length of the optical system, Σat is the sum of the separation distance of the first lens group and the second lens on the optical axis and the separation distance of the second lens and the third lens on the optical axis. And 8<f/Sigma AT <150 is satisfied, and the lens spacing is smaller by controlling the ratio of the effective focal length of the optical system to the on-axis distance between the three lenses, so that the ghost image intensity between the lenses is reduced.
In an exemplary embodiment, the optical system of the present application may satisfy: 0.6< DT11/TD <1.8, wherein DT11 is the effective radius of the first side of the first lens and TD is the distance on the optical axis from the first side of the first lens to the second side of the third lens. Satisfies 0.6< D11/TD <1.8, and the effective radius of the first side surface of the first lens and the axial distance from the first side surface of the first lens to the second side surface of the third lens are controlled, namely the ratio of the caliber to the thickness of the lens is controlled, the strength of the lens is ensured, and the reliability of an optical system is facilitated.
In an exemplary embodiment, the optical system of the present application may satisfy: -7.0< (r1+rbs)/f < -1.5, where R1 is the radius of curvature of the first side of the first lens, RBS is the radius of curvature of the surface of the lens where the partially reflective layer is located, and f is the effective focal length of the optical system. Satisfying-7.0 < (R1+RBS)/f < -1.5, by controlling the ratio of the sum of the radius of curvature of the first side surface of the first lens and the radius of curvature of the surface of the lens where the partial reflecting layer is positioned to the effective focal length of the optical system, the included angle between the light ray and the surface of the first lens can be reduced at the first side surface of the first lens, the possible aberration generated at the position can be effectively reduced, and the imaging quality of the optical system can be improved.
In an exemplary embodiment, the optical system of the present application may satisfy: -5< R1/f < -0.7, wherein R1 is the radius of curvature of the first side of the first lens and f is the effective focal length of the optical system. And the ratio of the curvature radius of the first side surface of the first lens to the effective focal length of the optical system is controlled to be minus 5< R1/f < -0.7, so that the first side surface of the first lens is beneficial to being controlled to be concave, the ratio is smaller, the curvature of the concave is smaller, light vertically enters the first side surface of the first lens, and aberration introduced by the first lens is reduced.
In an exemplary embodiment, the optical system of the present application may satisfy: -8< SAG11/CT1 XFNo < -4, wherein SAG11 is the distance on the optical axis between the intersection of the first side of the first lens on the optical axis and the vertex of the maximum effective radius of the first side of the first lens, CT1 is the central thickness of the first lens on the optical axis, FNo is the f-number of the optical system. Meets the requirements of-8 < SAG11/CT1 x FNo < -4, constrains the ratio of the sagittal height of the first side surface of the first lens to the central thickness of the first lens, and is beneficial to ensuring the molding of the first lens.
In an exemplary embodiment, the optical system of the present application may satisfy: 0< SAG22/R4<40.5, wherein SAG22 is the distance on the optical axis from the intersection of the second side of the second lens to the maximum effective radius vertex of the second side of the second lens, and R4 is the radius of curvature of the second side of the second lens. Satisfies 0< SAG22/R4<40.5, and indirectly controls the effective caliber of the second lens by controlling the sagittal height of the second side surface of the second lens and the curvature radius of the second side surface of the second lens, thereby being beneficial to miniaturization of the optical system.
In an exemplary embodiment, the optical system of the present application may satisfy: 1.5< f×tan (FOV/2)/Σct <3.5, where f is the effective focal length of the optical system, FOV is the maximum field angle of the optical system, Σct is the sum of the central thicknesses of the reflective polarizing element, quarter wave plate, first lens, second lens, and third lens on the optical axis. f×tan (FOV/2) is the screen size, and the ratio of the screen size to the center thickness of each element in the optical system is controlled to be within a certain range by controlling the sum of the screen size and the center thickness of each element in the optical system, namely, the ratio of 1.5< f×tan (FOV/2)/ΣCT <3.5 is satisfied, and the thickness of the optical system is effectively controlled on the premise of a certain screen size, thereby being beneficial to reducing the size of the optical system.
In an exemplary embodiment, the first lens group has positive optical power, the second lens has positive optical power, the third lens has negative optical power and the first side thereof is concave. The first lens group and the second lens are of positive focal power, so that light convergence is facilitated, and the light height is compressed; the third lens is of negative focal power, and the first lens group and the second lens are combined, so that positive and negative focal power collocation is beneficial to correcting system aberration.
In an exemplary embodiment, the third lens has positive optical power and its second side is convex. The third lens has positive focal power and the second side is convex, which is beneficial to further compressing the light height, thereby reducing the screen size.
In an exemplary embodiment, the optical system of the present application may satisfy: 0.8< F1/F <1.2, wherein F1 is the effective focal length of the first lens group and F is the effective focal length of the optical system. Satisfying 0.8< F1/f <1.2, the optical power of the first lens group is positive by controlling the ratio of the effective focal length of the first lens group to the effective focal length of the optical system, and the value is close to the focal length of the system, so that the first lens group is beneficial to converging light rays, and the size of the subsequent lens group is beneficial to being reduced.
In an exemplary embodiment, the optical system of the present application may satisfy: and (CT1+CT2)/CT 3<11, wherein CT1 is the central thickness of the first lens on the optical axis, CT2 is the central thickness of the second lens on the optical axis, and CT3 is the central thickness of the third lens on the optical axis. The ratio of the central thickness of the first lens and the second lens on the optical axis to the central thickness of the third lens on the optical axis is controlled to be larger, the folding length of the light path is ensured, and the length of the optical system is reduced.
In an exemplary embodiment, the optical system of the present application may satisfy: 0.2< CT3/(f×tan (FOV/2)) <0.5, wherein CT3 is the center thickness of the third lens on the optical axis, f is the effective focal length of the optical system, and FOV is the maximum field angle of the optical system. f×tan (FOV/2) is a screen size, and the distance from the first lens to the third lens is indirectly controlled by controlling the ratio of the center thickness of the third lens to the screen size to be smaller, so that the optical path refractive-back length is constrained.
In an exemplary embodiment, the optical system of the present application may satisfy: -1.1< R6/f3< -0.1, wherein R6 is the radius of curvature of the second side of the third lens and f3 is the effective focal length of the third lens. Satisfies-1.1 < R6/f3< -0.1, effectively constrains the shape of the third lens by controlling the ratio of the radius of curvature of the second side surface of the third lens to the effective focal length of the third lens, and is beneficial to the molding of the third lens.
In an exemplary embodiment, the optical system of the present application may satisfy: 2< (V1-V2) ×f/F1<5, wherein V1 is the dispersion coefficient of the first lens, V2 is the dispersion coefficient of the second lens, F is the effective focal length of the optical system, and F1 is the effective focal length of the first lens group. Satisfying 2< (V1-V2) xf/F1 <5, and by controlling the dispersion coefficients of the first lens and the second lens, the effective focal length of the first lens group and the effective focal length of the optical system, the monochromatic aberration and chromatic aberration of the constraint system are facilitated, so that the imaging quality of the system is improved.
In an exemplary embodiment, the optical system of the present application may include at least one aperture. The diaphragm can restrict the light path and control the intensity of light. The aperture may be arranged in a suitable position of the optical system, for example the aperture may be located on the first side of the first lens.
In an exemplary embodiment, the effective focal length F of the optical system may be, for example, in the range of 25.5mm to 33.8mm, the focal length F1 of the first lens group may be, for example, in the range of-229.0 mm to 9656.0mm, the effective focal length F2 of the second lens may be, for example, in the range of-940.0 mm to 322.0mm, and the effective focal length F3 of the third lens may be, for example, in the range of-474.0 mm to 348.0 mm.
According to some embodiments of the present application, the optical system according to the present application is a low-volume optical system of high definition imaging quality, and in application, the optical system according to the exemplary embodiments of the present application may be suitable for VR devices. By reasonably setting the effective focal length, the maximum field angle, the entrance pupil diameter, the center thickness of the lens, the refractive index, the Abbe number, the curvature radius and other parameters of the optical system, and by reasonably setting the diaphragm parameters, the purpose of wide angle of the VR device can be met, the chromatic aberration of the system can be corrected, and the imaging quality of the system can be improved. The bearing elements are arranged between the lenses, so that the processing and forming performances of the lenses can be facilitated, the sensitivity of the lenses can be reduced, the assembly yield can be improved, and the VR equipment miniaturization target can be met on the premise of ensuring the performances of the optical system.
Specific examples of the optical system applicable to the above-described embodiments are further described below with reference to the drawings.
Example 1
An optical system according to embodiment 1 of the present application is described below with reference to fig. 2 to 3C. Fig. 2 shows a schematic configuration of an optical system according to embodiment 1 of the present application.
As shown in fig. 2, the optical system sequentially includes, from a first side to a second side along the optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 2, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S4 of the first lens E1.
Table 1 shows basic parameters of the optical system of example 1, in which the unit of radius of curvature and thickness are both millimeters (mm). Table 1 only exemplifies the correspondence between the surface numbers of the partial surfaces and the partial elements, and the positions of the common surfaces in table 1 are inconvenient to mark all the elements due to the problem of the common surfaces of the adjacent elements.
Figure SMS_1
Figure SMS_2
TABLE 1
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP in order to the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S4 of the first lens E1 and passes through the first lens E1, the quarter wave plate QWP, the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S4 of the first lens E1. In an example, the partially reflective layer may be plated at a region of the second side S4 of the first lens E1 away from the optical axis.
In embodiment 1, the reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the third lens E3 are all aspheric on the first side and the second side, and the surface form x of each aspheric lens can be defined by, but not limited to, the following aspheric formula:
Figure SMS_3
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,
Figure SMS_4
is the radial distance; r is (r) n Is normalized radius; u is r/r n ；a m Is the mth order Q con Coefficients; q (Q) m con Is the mth order Q con A polynomial. Table 2 below shows the higher order coefficients a that can be used for each of the aspherical mirrors S1, S2, S3, S4, S5, S6, S7 and S8 in example 1 0 、a 1 、a 2 And a 3 。
Face number a 0 a 1 a 2 a 3
S1 -9.6015E-02 -2.8221E-02 3.0950E-02 2.2307E-03
S2 -9.6015E-02 -2.8221E-02 3.0950E-02 2.2307E-03
S3 -9.6015E-02 -2.8221E-02 3.0950E-02 2.2307E-03
S4 -1.7536E-01 2.1371E-02 1.4276E-02 -2.2234E-03
S5 -3.8312E-01 1.7814E-01 -8.7838E-02 -1.2893E-02
S6 -2.1499E-01 4.7951E-01 2.2208E-01 -7.7146E-02
S7 1.6150E-01 1.6404E-01 -3.0321E-02 -7.0093E-02
S8 -3.1354E-02 3.8923E-01 -1.4739E-01 -1.6540E-02
TABLE 2
Table 3 shows values of parameters such as the maximum field angle FOV, F-stop F no, effective focal length F of the optical system, effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), effective focal length F2 of the second lens E2, and effective focal length F3 of the third lens E3 of the optical system in embodiment 1.
Figure SMS_5
TABLE 3 Table 3
Fig. 3A shows an on-axis chromatic aberration curve of the optical system of embodiment 1, which indicates the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 3B shows an astigmatism curve of the optical system of embodiment 1, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 3C shows a distortion curve of the optical system of embodiment 1, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 3A to 3C, the optical system of embodiment 1 can achieve good imaging quality.
Example 2
An optical system according to embodiment 2 of the present application is described below with reference to fig. 4 to 5C. In this embodiment and the following embodiments, descriptions of portions similar to embodiment 1 will be omitted for brevity. Fig. 4 shows a schematic structural view of an optical system according to embodiment 2 of the present application.
As shown in fig. 4, the optical system sequentially includes, from a first side to a second side along an optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 4, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S4 of the first lens E1.
Table 4 shows basic parameters of the optical system of example 2, in which the unit of radius of curvature and thickness are both millimeters (mm). Table 4 only exemplifies the correspondence between the surface numbers of the partial surfaces and the partial elements, and the positions of the common surfaces in table 4 are inconvenient to mark all the elements due to the problem of the common surfaces of the bonding between the adjacent elements. Table 5 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 2, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Figure SMS_6
Figure SMS_7
/>
TABLE 4 Table 4
Face number a 0 a 1 a 2 a 3
S1 2.2678E-01 4.8368E-02 -3.8900E-03 -1.4582E-02
S2 2.2678E-01 4.8368E-02 -3.8900E-03 -1.4582E-02
S3 2.2678E-01 4.8368E-02 -3.8900E-03 -1.4582E-02
S4 1.7070E-01 2.8904E-02 -1.8839E-02 -1.5550E-03
S5 1.7934E-01 4.5977E-02 -6.8587E-02 2.6923E-02
S6 -1.9511E-01 6.7312E-02 1.4206E-01 5.0502E-02
S7 -4.3142E-02 8.5068E-03 2.4669E-01 1.2067E-01
S8 -1.1994E-01 2.2683E-01 2.6295E-02 2.7582E-02
TABLE 5
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP in order to the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S4 of the first lens E1 and passes through the first lens E1, the quarter wave plate QWP, the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S4 of the first lens E1. In an example, the partially reflective layer may be plated at a region of the second side S4 of the first lens E1 away from the optical axis.
Table 6 shows values of parameters such as the maximum field angle FOV of the optical system, the F-stop F no, the effective focal length F of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), the effective focal length F2 of the second lens E2, and the effective focal length F3 of the third lens E3 in example 2.
Figure SMS_8
TABLE 6
Fig. 5A shows an on-axis chromatic aberration curve of the optical system of embodiment 2, which represents the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 5B shows an astigmatism curve of the optical system of embodiment 2, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 5C shows a distortion curve of the optical system of embodiment 2, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 5A to 5C, the optical system according to embodiment 2 can achieve good imaging quality.
Example 3
An optical system according to embodiment 3 of the present application is described below with reference to fig. 6 to 7C. Fig. 6 shows a schematic structural diagram of an optical system according to embodiment 3 of the present application.
As shown in fig. 6, the optical system sequentially includes, from a first side to a second side along an optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 6, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S6 of the second lens E2.
Table 7 shows basic parameters of the optical system of example 3, in which the unit of radius of curvature and thickness are both millimeters (mm). Table 7 only exemplifies the correspondence between the surface numbers of the partial surfaces and the partial elements, and the positions of the common surfaces in table 7 are inconvenient to mark all the elements due to the problem of the common surfaces of the bonding between the adjacent elements. Table 8 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 3, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Surface of the body Element name Surface type Radius of curvature Thickness of (L) Refractive index Abbe number Refraction/reflection
Spherical surface Infinity is provided Infinity is provided
STO Diaphragm (STO) Spherical surface Infinity is provided 22.4497 Refraction by refraction
S1 Reflective polarizerPiece (RP) Aspherical surface -52.3329 0.2000 1.50 57.00 Refraction by refraction
S2 Quarter Wave Plate (QWP) Aspherical surface -52.3329 0.2000 1.50 57.00 Refraction by refraction
S3 First lens (E1) Aspherical surface -52.3329 5.0189 1.48 60.00 Refraction by refraction
S4 Aspherical surface -44.7519 1.5303 Refraction by refraction
S5 Second lens (E2) Aspherical surface -38.8319 1.8496 1.68 19.00 Refraction by refraction
S6 Partial reflecting member (BS) Aspherical surface -42.1501 -1.8496 1.68 19.00 Reflection of
S5 Aspherical surface -38.8319 -1.5303 Refraction by refraction
S4 Aspherical surface -44.7519 -5.0189 1.48 60.00 Refraction by refraction
S3 Quarter Wave Plate (QWP) Aspherical surface -52.3329 -0.2000 1.50 57.00 Refraction by refraction
S2 Aspherical surface -52.3329 0.2000 1.50 57.00 Reflection of
S3 Aspherical surface -52.3329 5.0189 Refraction by refraction
S4 Aspherical surface -44.7519 1.5303 Refraction by refraction
S5 Second lens (E2) Aspherical surface -38.8319 1.8496 1.68 19.00 Refraction by refraction
S6 Aspherical surface -42.1501 0.1000 Refraction by refraction
S7 Third lens (E3) Aspherical surface 65.3211 19.3368 1.48 59.83 Refraction by refraction
S8 Aspherical surface -81.1681 2.8335 Refraction by refraction
S9 Display (S9) Spherical surface Infinity is provided
TABLE 7
Figure SMS_9
Figure SMS_10
TABLE 8
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP, and then reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again to the second lens E2, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S6 of the second lens E2 and passes through the second lens E2, the first lens E1, the quarter wave plate QWP, and the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the human eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S6 of the second lens E2. In an example, the partially reflective layer may be plated at a region of the second side surface S6 of the second lens E2 away from the optical axis.
Table 9 shows values of parameters such as the maximum field angle FOV of the optical system, the F-stop F no, the effective focal length F of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), the effective focal length F2 of the second lens E2, and the effective focal length F3 of the third lens E3 in example 3.
Figure SMS_11
TABLE 9
Fig. 7A shows an on-axis chromatic aberration curve of the optical system of embodiment 3, which indicates the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 7B shows an astigmatism curve of the optical system of embodiment 3, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 7C shows a distortion curve of the optical system of example 3, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 7A to 7C, the optical system provided in embodiment 3 can achieve good imaging quality.
Example 4
An optical system according to embodiment 4 of the present application is described below with reference to fig. 8 to 9C. Fig. 8 shows a schematic structural diagram of an optical system according to embodiment 4 of the present application.
As shown in fig. 8, the optical system sequentially includes, from a first side to a second side along the optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 8, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S6 of the second lens E2.
Table 10 shows basic parameters of the optical system of example 4, in which the unit of radius of curvature and thickness are both millimeters (mm). The correspondence between the surface numbers of the partial surfaces and the partial elements is shown in table 10 only by way of example, and the positions of the common surfaces in table 10 are inconvenient to mark all the elements due to the problem of the common surfaces of the adjacent elements. Table 11 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 4, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Surface of the body Element name Surface type Radius of curvature Thickness of (L) Refractive index Abbe number Refraction/reflection
Spherical surface Infinity is provided Infinity is provided
STO Diaphragm (STO) Spherical surface Infinity is provided 17.9275 Refraction by refraction
S1 Reflective polarizing element (RP) Aspherical surface -87.3615 0.2000 1.50 57.00 Refraction by refraction
S2 Quarter Wave Plate (QWP) Aspherical surface -87.3615 0.2000 1.50 57.00 Refraction by refraction
S3 First lens (E1) Aspherical surface -87.3615 2.4764 1.68 19.05 Refraction by refraction
S4 Aspherical surface -226.9014 0.3387 Refraction by refraction
S5 Second lens (E2) Aspherical surface -190.2984 8.2212 1.49 55.39 Refraction by refraction
S6 Partial reflecting member (BS) Aspherical surface -52.9129 -8.2212 1.49 55.39 Reflection of
S5 Aspherical surface -190.2984 -0.3387 Refraction by refraction
S4 Aspherical surface -226.9014 -2.4764 1.68 19.05 Refraction by refraction
S3 Quarter Wave Plate (QWP) Aspherical surface -87.3615 -0.2000 1.50 57.00 Refraction by refraction
S2 Aspherical surface -87.3615 0.2000 1.50 57.00 Reflection of
S3 Aspherical surface -87.3615 2.4764 Refraction by refraction
S4 Aspherical surface -226.9014 0.3387 Refraction by refraction
S5 Second lens (E2) Aspherical surface -190.2984 8.2212 1.49 55.39 Refraction by refraction
S6 Aspherical surface -52.9129 3.0734 Refraction by refraction
S7 Third lens (E3) Aspherical surface 175.2235 11.3445 1.61 23.11 Refraction by refraction
S8 Aspherical surface -74.4238 1.4766 Refraction by refraction
S9 (S9) Spherical surface Infinity is provided
Table 10
Face number a 0 a 1 a 2 a 3
S1 1.7318E-01 9.6863E-02 -4.4572E-02 5.2719E-03
S2 1.7318E-01 9.6863E-02 -4.4572E-02 5.2719E-03
S3 1.7318E-01 9.6863E-02 -4.4572E-02 5.2719E-03
S4 -2.5063E-01 8.8944E-02 1.2895E-02 -1.8220E-02
S5 2.3471E-01 7.6660E-02 -2.4657E-03 -6.3724E-02
S6 2.1155E-01 1.0203E-01 -8.2616E-02 9.2680E-03
S7 -1.0376E+00 -2.1803E-01 2.5416E-02 2.8979E-01
S8 1.2916E+00 -2.7952E-01 -1.2674E-03 6.6774E-02
TABLE 11
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP, and then reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again to the second lens E2, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S6 of the second lens E2 and passes through the second lens E2, the first lens E1, the quarter wave plate QWP, and the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the human eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S6 of the second lens E2. In an example, the partially reflective layer may be plated at a region of the second side surface S6 of the second lens E2 away from the optical axis.
Table 12 shows values of parameters such as the maximum field angle FOV, F-stop F no, effective focal length F of the optical system, effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), effective focal length F2 of the second lens E2, and effective focal length F3 of the third lens E3 of the optical system in example 4.
Figure SMS_12
Table 12
Fig. 9A shows an on-axis chromatic aberration curve of the optical system of embodiment 4, which indicates the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 9B shows an astigmatism curve of the optical system of embodiment 4, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 9C shows a distortion curve of the optical system of example 4, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 9A to 9C, the optical system provided in embodiment 4 can achieve good imaging quality.
Example 5
An optical system according to embodiment 5 of the present application is described below with reference to fig. 10 to 11C. Fig. 10 shows a schematic structural diagram of an optical system according to embodiment 5 of the present application.
As shown in fig. 10, the optical system sequentially includes, from a first side to a second side along an optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 10, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S6 of the second lens E2.
Table 13 shows basic parameters of the optical system of example 5, in which the unit of radius of curvature and thickness are both millimeters (mm). Table 13 only exemplifies the correspondence between the surface numbers of the partial surfaces and the partial elements, and the positions of the common surfaces in table 13 are inconvenient to mark all the elements due to the problem of the common surfaces of the adjacent elements. Table 14 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 5, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Figure SMS_13
Figure SMS_14
TABLE 13
Face number a 0 a 1 a 2 a 3
S1 -1.4345E-01 6.8938E-02 1.8020E-02 -1.0906E-06
S2 -1.4345E-01 6.8938E-02 1.8020E-02 -1.0906E-06
S3 -1.4345E-01 6.8938E-02 1.8020E-02 -1.0906E-06
S4 -3.2276E-01 2.8809E-02 -2.9282E-02 -4.3712E-02
S5 3.1209E-01 -4.7400E-02 -1.5831E-01 -6.6148E-03
S6 -2.0127E-02 4.1501E-02 -2.8304E-02 2.2660E-02
S7 -2.0946E-01 1.9303E-01 -3.2473E-02 4.8329E-02
S8 5.9797E-01 7.5649E-02 -3.0103E-01 1.0044E-01
TABLE 14
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP, and then reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again to the second lens E2, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S6 of the second lens E2 and passes through the second lens E2, the first lens E1, the quarter wave plate QWP, and the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the human eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S6 of the second lens E2. In an example, the partially reflective layer may be plated at a region of the second side surface S6 of the second lens E2 away from the optical axis.
Table 15 shows values of parameters such as the maximum field angle FOV of the optical system, the F-stop F no, the effective focal length F of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), the effective focal length F2 of the second lens E2, and the effective focal length F3 of the third lens E3 in example 5.
Figure SMS_15
TABLE 15
Fig. 11A shows an on-axis chromatic aberration curve of the optical system of embodiment 5, which indicates the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 11B shows an astigmatism curve of the optical system of embodiment 5, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 11C shows a distortion curve of the optical system of example 5, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 11A to 11C, the optical system provided in embodiment 5 can achieve good imaging quality.
Example 6
An optical system according to embodiment 6 of the present application is described below with reference to fig. 12 to 13C. Fig. 12 shows a schematic structural diagram of an optical system according to embodiment 6 of the present application.
As shown in fig. 12, the optical system includes, in order from a first side to a second side along an optical axis: stop STO, reflective polarizer RP, quarter wave plate QWP, first lens E1, second lens E2, third lens E3, and display S9.
As shown in fig. 12, the reflective polarizing element RP has a first side surface S1 and a second side surface S2, the quarter wave plate QWP has a first side surface S2 and a second side surface S3, and the first lens E1 has a first side surface S3 and a second side surface S4. S2 is a common surface of the second side surface of the reflective polarizing element RP and the first side surface of the quarter wave plate QWP, and the second side surface of the reflective polarizing element RP is attached to the first side surface of the quarter wave plate QWP; s3 is a common surface of the second side surface of the quarter wave plate QWP and the first side surface of the first lens E1, and the second side surface of the quarter wave plate QWP is attached to the first side surface of the first lens E1. The second lens E2 has a first side surface S5 and a second side surface S6. The third lens E3 has a first side S7 and a second side S8. The optical system further includes a partially reflective layer BS (not shown) disposed on the second side S6 of the second lens E2.
Table 16 shows basic parameters of the optical system of example 6, in which the unit of radius of curvature and thickness are both millimeters (mm). Table 16 only exemplifies the correspondence between the surface numbers of the partial surfaces and the partial elements, and the positions of the common surfaces in table 16 are inconvenient to mark all the elements due to the problem of the common surfaces of the adjacent elements. Table 17 shows the higher order coefficients that can be used for each of the aspherical mirror surfaces in example 6, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Figure SMS_16
Figure SMS_17
Table 16
Face number a 0 a 1 a 2 a 3
S1 -2.1712E-02 1.3117E-01 -1.0344E-02 -1.7705E-03
S2 -2.1712E-02 1.3117E-01 -1.0344E-02 -1.7705E-03
S3 -2.1712E-02 1.3117E-01 -1.0344E-02 -1.7705E-03
S4 -2.2357E-01 6.8785E-02 5.8637E-03 1.3164E-02
S5 2.9870E-01 5.5230E-02 5.5996E-03 4.1828E-03
S6 -1.7381E-01 1.5302E-01 -3.4292E-02 1.0244E-03
S7 -2.4055E-01 -1.6728E-01 -1.7089E-01 6.1945E-02
S8 -5.6240E-02 -1.0233E-01 -2.2354E-01 3.2467E-02
TABLE 17
For example, when the optical system is applied to, for example, a VR device, the first side may, for example, be the human eye side and the second side may, for example, be the display side. Light from the display S9 passes through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP, and then reaches the reflective polarizing element RP, is reflected at the reflective polarizing element RP and passes through the quarter wave plate QWP and the first lens E1 again to the second lens E2, and then the light beam is reflected again at the partially reflective layer BS on the second side surface S6 of the second lens E2 and passes through the second lens E2, the first lens E1, the quarter wave plate QWP, and the reflective polarizing element RP in order, passes through the aperture stop STO and finally exits toward the human eye side. In an exemplary embodiment, the partially reflective layer may be a semi-transparent and semi-reflective film layer plated on the second side S6 of the second lens E2. In an example, the partially reflective layer may be plated at a region of the second side surface S6 of the second lens E2 away from the optical axis.
Table 18 shows values of parameters such as the maximum field angle FOV of the optical system, the F-stop F no, the effective focal length F of the optical system, the effective focal length F1 of the first lens group (including the reflective polarizing element RP, the quarter-wave plate QWP, and the first lens E1), the effective focal length F2 of the second lens E2, and the effective focal length F3 of the third lens E3 in example 6.
Figure SMS_18
TABLE 18
Fig. 13A shows an on-axis chromatic aberration curve of the optical system of embodiment 6, which indicates the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 13B shows an astigmatism curve of the optical system of example 6, which represents meridional image plane curvature and sagittal image plane curvature. Fig. 13C shows a distortion curve of the optical system of example 6, which represents distortion magnitude values corresponding to different half angles of view. As can be seen from fig. 13A to 13C, the optical system provided in embodiment 6 can achieve good imaging quality.
In summary, the relationships shown in the optical system table 19 of examples 1 to 6.
Figure SMS_19
Figure SMS_20
TABLE 19
The present application also provides an optical device that may be a stand-alone projection device, such as a projector, or may be a projection module integrated on a mobile electronic device, such as a VR. The optical apparatus is equipped with the optical system described above.
The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It should be understood by those skilled in the art that the scope of protection referred to in this application is not limited to the specific combination of the above technical features, but also encompasses other technical solutions formed by any combination of the above technical features or their equivalents without departing from the spirit of the application. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims (10)

1. An optical system, comprising, in order from a first side to a second side along an optical axis: a first lens group, a second lens and a third lens, wherein,
the first lens group sequentially comprises from a first side to a second side: the device comprises a reflective polarizing element, a quarter wave plate and a first lens, wherein a second side surface of the reflective polarizing element is attached to a first side surface of the quarter wave plate, and a second side surface of the quarter wave plate is attached to a first side surface of the first lens;
a partial reflection layer is arranged on at least one of the second side surface of the first lens, the first side surface and the second side surface of the second lens;
The first side surface of the first lens is a concave surface, and the second side surface of the first lens is a convex surface;
the second side surface of the second lens is a convex surface; and
the radius of curvature R1 of the first side of the first lens and the radius of curvature R4 of the second side of the second lens satisfy: 0< R1/R4<2.
2. The optical system according to claim 1, wherein a center thickness CT1 of the first lens on the optical axis, a distance TD between a first side of the first lens and a second side of the third lens on the optical axis satisfies: 0< CT1/TD <0.6.
3. The optical system according to claim 1, wherein an abbe number V1 of the first lens, an abbe number V2 of the second lens, an abbe number V3 of the third lens, an abbe number VRP of the reflective polarizing element, and an abbe number VQWP of the quarter wave plate satisfy:
30< (v1+v2+v3)/3 < vrp and 30< (v1+v2+v3)/3 < vqwp.
4. The optical system according to claim 1, wherein a distance Tr1rBS on the optical axis from the first side of the first lens to the surface of the lens where the partially reflective layer is located and a distance TD on the optical axis from the first side of the first lens to the second side of the third lens satisfy: 0.3< Tr1rBS/TD <0.7.
5. The optical system according to claim 1, wherein a radius of curvature R1 of the first side of the first lens, a center thickness CTRP of the reflective polarizing element on the optical axis, and a center thickness CTQWP of the quarter wave plate on the optical axis satisfy: -310< R1/(CTRP+CTQWP) < -40.
6. The optical system according to claim 1, wherein a sum Σat of an effective focal length f of the optical system, a separation distance of the first lens group from the second lens on the optical axis, and a separation distance of the second lens from the third lens on the optical axis satisfies: 8<f/Σat <150.
7. The optical system according to claim 1, wherein an effective radius DT11 of the first side of the first lens, a distance TD between the first side of the first lens and the second side of the third lens on the optical axis satisfies: 0.6< DT11/TD <1.8.
8. The optical system according to claim 1, wherein a radius of curvature R1 of the first side surface of the first lens, a radius of curvature RBS of a surface of the lens where the partially reflective layer is located, and an effective focal length f of the optical system satisfy: -7.0< (r1+rbs)/f < -1.5.
9. The optical system according to any one of claims 1 to 8, wherein a radius of curvature R1 of the first side of the first lens and an effective focal length f of the optical system satisfy: -5< R1/f < -0.7.
10. Optical device, characterized in that it comprises an optical system according to at least one of claims 1 to 9.
CN202310496640.5A 2023-04-27 2023-04-27 Optical system and optical apparatus including the same Pending CN116400485A (en)

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