CN116880046A - Optical system - Google Patents

Optical system Download PDF

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Publication number
CN116880046A
CN116880046A CN202310980758.5A CN202310980758A CN116880046A CN 116880046 A CN116880046 A CN 116880046A CN 202310980758 A CN202310980758 A CN 202310980758A CN 116880046 A CN116880046 A CN 116880046A
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CN
China
Prior art keywords
lens
element group
optical system
wave plate
quarter wave
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310980758.5A
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Chinese (zh)
Inventor
姚嘉诚
张晓彬
戴付建
赵烈烽
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhejiang Sunny Optics Co Ltd
Original Assignee
Zhejiang Sunny Optics Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhejiang Sunny Optics Co Ltd filed Critical Zhejiang Sunny Optics Co Ltd
Priority to CN202310980758.5A priority Critical patent/CN116880046A/en
Publication of CN116880046A publication Critical patent/CN116880046A/en
Pending legal-status Critical Current

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Classifications

    • 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
    • G02B13/004—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 four lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • 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
    • G02B13/009—Miniaturised objectives for electronic devices, e.g. portable telephones, webcams, PDAs, small digital cameras having zoom function
    • 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
    • G02B15/00—Optical objectives with means for varying the magnification
    • G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • 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
    • G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
    • 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
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • 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
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/011—Head-up displays characterised by optical features comprising device for correcting geometrical aberrations, distortion
    • 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
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/0123—Head-up displays characterised by optical features comprising devices increasing the field of view
    • 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
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G02B2027/013—Head-up displays characterised by optical features comprising a combiner of particular shape, e.g. curvature

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

Abstract

The application discloses an optical system, which sequentially comprises a first element group, a second element group, a third element group and a fourth element group from a first side to a second side along an optical axis; the first element group comprises a first lens, a reflective polarizing element and a first quarter wave plate; the second element group comprises a second lens and a second quarter wave plate; the third element group comprises a third lens; the fourth element group comprises a fourth lens; wherein the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens, and the on-axis distance TD between the first side of the first element group and the second side of the fourth element group and the total effective focal length f of the optical system satisfy: TD/f <1.5.

Description

Optical system
Technical Field
The application relates to the field of optical devices, in particular to a foldback optical system.
Background
As the demand of users for virtual reality devices increases, higher demands are also being placed on optical systems in virtual reality devices, for example, optical systems need to have high resolution and small size.
The following two methods are generally employed to ensure that the optical system has a small size without affecting the angle of view of the optical system. The first method is to ensure a small size of the optical system by reducing the viewing distance of the optical system, which means that the eyes of the user are close to the optical system, which may cause muscular tension of the eyes of the user, thereby affecting the comfort of use of the user. The second method is to guide the returning light to the small image plane by increasing the number of lenses included in the optical system, which leads to an increase in processing or assembly tolerance of the optical system and an increase in the optical overall length of the optical system. In addition, the optical system often attaches a film layer such as a reflective polarizing element or a quarter wave plate on a curved surface with a certain curvature, and the quality of the film layer such as the reflective polarizing element or the quarter wave plate after film attachment is degraded due to the complex curved surface film attaching process, so that the performance of the optical system is degraded.
Disclosure of Invention
The present application 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 application provides an optical system including, in order from a first side to a second side along an optical axis, a first element group, a second element group, a third element group, and a fourth element group; the first element group comprises a first lens, a reflective polarizing element and a first quarter wave plate; the second element group comprises a second lens and a second quarter wave plate; the third element group comprises a third lens; the fourth element group comprises a fourth lens; wherein the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens, and the on-axis distance TD between the first side of the first element group and the second side of the fourth element group and the total effective focal length f of the optical system satisfy: TD/f <1.5.
According to an exemplary embodiment of the present application, the center thickness CT3 of the third lens on the optical axis, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the air interval T23 of the second element group and the third element group on the optical axis satisfy: 8.0< CT3/((N2+N3). Times.T23) <12.0.
According to an exemplary embodiment of the present application, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T23 of the second element group and the third element group on the optical axis, the abbe number V2 of the second lens, the abbe number V3 of the third lens, the effective focal length F2 of the second element group, and the effective focal length F3 of the third element group satisfy: (t23+ct2+ct3) × (v2+v3)/| (f2+f3) | <10.0.
According to an exemplary embodiment of the present application, the maximum field angle FOV of the optical system satisfies: 80 ° < FOV <120 °.
According to an exemplary embodiment of the present application, the radius of curvature R2 of the second side surface of the first lens, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the air interval T12 of the first element group and the second element group on the optical axis, the refractive index N1 of the first lens, and the refractive index N2 of the second lens satisfy: -3.0< r 2/((CT 1+ T12+ CT 2) × (N1 + N2)) <0.
According to an exemplary embodiment of the present application, the radius of curvature R5 of the first side of the third lens and the radius of curvature R6 of the second side of the third lens satisfy: 0.2< (R5-R6)/(R5+R6) <1.5.
According to an exemplary embodiment of the present application, the radius of curvature R7 of the first side of the fourth lens, the radius of curvature R8 of the second side of the fourth lens, and the effective focal length F4 of the fourth element group satisfy: 0< F4/R7-F4/R8<2.0.
According to an exemplary embodiment of the present application, the radius of curvature R6 of the second side of the third lens, the radius of curvature R8 of the second side of the fourth lens, the center thickness CT3 of the third lens on the optical axis, the center thickness CT4 of the fourth lens on the optical axis, and the air space T34 of the third element group and the fourth element group on the optical axis satisfy: 15.0< (R6-R8)/(CT3+T34+CT4) <0.
According to an exemplary embodiment of the present application, the dispersion coefficient V3 of the third lens, the dispersion coefficient V4 of the fourth lens, the center thickness CT3 of the third lens on the optical axis, the center thickness CT4 of the fourth lens on the optical axis, the effective focal length F3 of the third element group, and the effective focal length F4 of the fourth element group satisfy: 2.0< (v3×ct3+v4×ct4)/(f3+f4) <6.5.
According to an exemplary embodiment of the present application, the on-axis distance TD of the first side of the first element group to the second side of the fourth element group, the maximum field angle FOV of the optical system, and the total effective focal length f of the optical system satisfy: 0.5< TD/(tan (FOV/2). Times.f) <1.5.
According to an exemplary embodiment of the present application, the radius of curvature R5 of the first side of the third lens, the radius of curvature R6 of the second side of the third lens, and the effective focal length F3 of the third element group satisfy: 2.0< |R5+R6|/F3.
According to an exemplary embodiment of the present application, the effective focal length F3 of the third element group, the effective focal length F4 of the fourth lens group, the air interval T34 of the third element group and the fourth element group on the optical axis, the refractive index N3 of the third lens, the refractive index N4 of the fourth lens, and the total effective focal length F of the optical system satisfy: 0.2mm < (F3×T34/N3+F4×T34/N4)/F <2.0mm.
According to an exemplary embodiment of the present application, the effective focal length F1 of the first element group and the total effective focal length F of the optical system satisfy: F1/F <2.0.
According to an exemplary embodiment of the present application, the effective focal length F3 of the third element group and the total effective focal length F of the optical system satisfy: 0< F3/f <20.0.
According to an exemplary embodiment of the present application, the effective focal length F4 of the fourth element group and the total effective focal length F of the optical system satisfy: 0< F4/f <10.0.
According to an exemplary embodiment of the present application, the central thickness CTR of the reflective polarizing element on the optical axis, the central thickness CTQ1 of the first quarter-wave plate on the optical axis, the central thickness CT1 of the first lens on the optical axis, the dispersion coefficient VR of the reflective polarizing element, the dispersion coefficient VQ1 of the first quarter-wave plate, the dispersion coefficient V1 of the first lens, and the effective focal length F1 of the first element group satisfy: 40.0< (CTR+CTQ1+CT1) × (VR+VQ1+V1)/F1 <70.0.
According to an exemplary embodiment of the present application, the refractive index NR of the reflective polarizing element, the refractive index NQ1 of the first quarter wave plate, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the radius of curvature R2 of the second side surface of the first lens, and the effective focal length F1 of the first element group satisfy: -5.0< (nr+nq1) ×r2/((n1+n2) ×f1) <0.
According to an exemplary embodiment of the present application, the maximum effective half-caliber DT31 of the first side of the third lens, the maximum effective half-caliber DT42 of the second side of the fourth lens, the radius of curvature R6 of the second side of the third lens, and the radius of curvature R8 of the second side of the fourth lens satisfy: (dt31+dt42)/| (r6+r8) | <1.0.
According to an exemplary embodiment of the present application, the radius of curvature R2 of the second side of the first lens, the maximum effective half-caliber DT12 of the second side of the first lens and the maximum effective half-caliber DT21 of the first side of the second lens satisfy: -2.0< R2/(DT 12+ DT 21) < -1.0.
According to an exemplary embodiment of the application, the second side of the first lens is provided with a partially reflective layer, the first side or the second side of the second lens being configured as a plane.
The optical system provided by the application is configured into a foldback optical system, the reflective polarizing element and/or the first quarter wave plate are/is attached on a plane in a plane film attaching mode, the attached quality of the reflective polarizing element and/or the first quarter wave plate can be ensured, the system performance is ensured, meanwhile, the reasonable focal length and smaller size of the optical system can be ensured as far as possible by restricting the ratio of the axial distance from the first side surface of the first element group to the second side surface of the fourth element group to the total effective focal length of the optical system and enabling the ratio to be smaller than 1.5, and meanwhile, the external view field performance of the optical system is optimized by the configuration among the structures.
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 structural view of an optical system according to the present application;
fig. 2 shows an enlarged view of region I of fig. 1;
fig. 3 shows a schematic configuration of an optical system according to embodiment 1 of the present application;
fig. 4A to 4C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 1 of the present application, respectively;
fig. 5 shows a schematic configuration of an optical system according to embodiment 2 of the present application;
fig. 6A to 6C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 2 of the present application, respectively;
fig. 7 shows a schematic configuration of an optical system according to embodiment 3 of the present application;
fig. 8A to 8C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 3 of the present application, respectively;
fig. 9 shows a schematic configuration of an optical system according to embodiment 4 of the present application;
fig. 10A to 10C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 4 of the present application, respectively;
Fig. 11 shows a schematic structural view of an optical system according to embodiment 5 of the present application;
fig. 12A to 12C 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. 13 shows a schematic structural view of an optical system according to embodiment 6 of the present application;
fig. 14A to 14C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 6 of the present application, respectively;
fig. 15 shows a schematic structural view of an optical system according to embodiment 7 of the present application;
fig. 16A to 16C show an on-axis chromatic aberration curve, an astigmatic curve, and a distortion curve of the optical system according to embodiment 7 of the present application, respectively;
fig. 17 shows a schematic configuration of an optical system according to embodiment 8 of the present application; and
fig. 18A to 18C show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical system according to embodiment 8 of the present application, respectively.
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 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.
Referring to fig. 1 and 2, a first aspect of the present application provides an optical system that may include a first element group, a second element group, a third element group, and a fourth element group sequentially arranged from a first side to a second side along an optical axis. The first element group may include, for example, a first lens, a reflective polarizing element, and a first quarter wave plate. The second element group may for example comprise a second lens and a second quarter wave plate. The third element group may, for example, include a third lens. The fourth element group may include, for example, a fourth lens. Adjacent ones of the first through fourth element groups may have an air space therebetween.
In an exemplary embodiment, the first side may be, for example, a human eye side and the second side may be, for example, a display side. Accordingly, the first side of each element (first lens, second lens, third lens, fourth lens, reflective polarizer, first quarter wave plate, second quarter wave plate) may be referred to as the near-eye side, and the second side may be referred to as the near-display side.
In an exemplary embodiment, the optical system may further comprise a stop, which may be arranged, for example, between the first side and the first lens. The image light on the display is refracted and reflected for many times by the fourth lens, the third lens, the second quarter wave plate, the first lens, the first quarter wave plate, the reflective polarizing element and the like, and finally projected to eyes of a user.
In an exemplary embodiment, the second side of the optical system may be provided with an image surface, which may be provided with a display, for example. The image light from the display can sequentially pass through the fourth lens, the third lens, the second quarter wave plate, the first lens and the first quarter wave plate to reach the reflective polarizing element, and then be reflected at the reflective polarizing element to form first reflected image light. The first reflected image light passes through the first quarter wave plate, the first lens and reaches the partially reflective layer, and then is reflected at the partially reflective layer to form second reflected image light. The second reflected image light passes through the first lens, the first quarter wave plate, the reflective polarizing element to the diaphragm in sequence and finally is projected into eyes of a user. In other examples, the order in which the image light passes through the second lens and the second quarter wave plate may be interchanged in forming the 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 body of the optical system is effectively shortened.
In an exemplary embodiment, the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens. The reflective polarizing element and/or the first quarter wave plate are/is attached to the plane by adopting a plane film attaching mode, so that the quality of the reflective polarizing element and/or the first quarter wave plate after being attached can be ensured, and the external visual field performance of the optical system is further improved.
As an example, the reflective polarizing element is attached to the first quarter wave plate and forms a film layer, and the attached film layer is attached to the first side surface of the first lens, where the reflective polarizing element is located on the first side surface of the first quarter wave plate. The reflective polarizing element and the first quarter wave plate are combined together to form one film layer, so that the number of attached surfaces of the film layer can be reduced, and the attached yield of the film layer is improved. And the film layer after compounding is attached to the plane, so that the stability of the film layer after attaching is improved, and the external visual field performance of the optical system is improved.
As an example, the first side or the second side of the second lens is configured to be planar, and the side of the second lens configured to be planar is provided with a second quarter wave plate. According to the optical system provided by the application, the first lens to the fourth lens are provided with two planes, and the aspheric designs of the third lens and the fourth lens are matched, so that the external visual field performance of the optical system can be improved.
In an exemplary embodiment, the optical system may further include a partially reflective layer, which may be attached to the second side of the first lens, for example. The partially reflective layer has a transflective effect on light. The second side surface of the first lens is provided with the partial reflecting layer, and the reflecting polarizing element and the first quarter wave plate of the first side surface of the first lens are combined, so that light rays can be folded back for many times, and the length of the body of the optical system is effectively reduced.
In an exemplary embodiment, the on-axis distance TD of the first side of the first element group to the second side of the fourth element group and the total effective focal length f of the optical system may satisfy: TD/f <1.5. In an example, 0.8< TD/f <1.3. By restricting the ratio of the on-axis distance of the first side face of the first element group to the second side face of the fourth element group to the total effective focal length of the optical system and making the above ratio smaller than 1.5, it is possible to ensure that the optical system has a reasonable focal length and a smaller size as much as possible, which is advantageous for realizing miniaturization of the optical system.
In an exemplary embodiment, the center thickness CT3 of the third lens on the optical axis, the refractive index N2 of the second lens, the refractive index N3 of the third lens, and the air interval T23 of the second element group and the third element group on the optical axis may satisfy: 8.0< CT3/((N2+N3). Times.T23) <12.0. Through making the third lens have reasonable thickness, collocation reasonable second lens's refractive index, third lens's refractive index and second element group and third element group's air interval on the optical axis simultaneously, can ensure that optical system has reasonable focal length to be favorable to shortening optical system's body length, and then ensure that optical system realizes miniaturization.
In an exemplary embodiment, the center thickness CT2 of the second lens on the optical axis, the center thickness CT3 of the third lens on the optical axis, the air interval T23 of the second element group and the third element group on the optical axis, the abbe number V2 of the second lens, the abbe number V3 of the third lens, the effective focal length F2 of the second element group, and the effective focal length F3 of the third element group may satisfy: (t23+ct2+ct3) × (v2+v3)/| (f2+f3) | <10.0. By controlling the conditional expression, the optical system can be ensured to have smaller body length and reasonable focal length, meanwhile, the chromatic aberration of the optical system is reduced by matching with the reasonable chromatic dispersion coefficients of the second lens and the third lens, and the multiband light transmission capability of the optical system is improved.
In an exemplary embodiment, the maximum field angle FOV of the optical system may satisfy: 80 ° < FOV <120 °. By restricting the maximum angle of view of the optical system and making the maximum angle of view in the range of 80 ° to 120 °, it is possible to ensure that the user has a good feeling of experience and that the optical system has good imaging performance.
In an exemplary embodiment, the radius of curvature R2 of the second side surface of the first lens, the center thickness CT1 of the first lens on the optical axis, the center thickness CT2 of the second lens on the optical axis, the air interval T12 of the first element group and the second element group on the optical axis, the refractive index N1 of the first lens, and the refractive index N2 of the second lens may satisfy: -3.0< r 2/((CT 1+ T12+ CT 2) × (N1 + N2)) <0. By controlling the conditions, the curvature radius of the second side surface of the first lens is in a reasonable range, so that the side surface is ensured to have good beam-converging performance on light rays when the light rays are reflected, and the beam-converging capability of the optical system on the light rays with large angle of view is improved; meanwhile, the optical system can be ensured to have smaller body length, and miniaturization of the optical system is facilitated.
In an exemplary embodiment, the radius of curvature R5 of the first side of the third lens and the radius of curvature R6 of the second side of the third lens may satisfy: 0.2< (R5-R6)/(R5+R6) <1.5. In an example, 0.5< (r5—r6)/(r5+r6) <1.1. By constraining the radii of curvature of the first side and the second side of the third lens and making the radii of curvature of both sides larger, the sensitivity of one side can be ensured and the processing difficulty of the third lens can be reduced.
In an exemplary embodiment, the radius of curvature R7 of the first side of the fourth lens, the radius of curvature R8 of the second side of the fourth lens, and the effective focal length F4 of the fourth element group may satisfy: 0< F4/R7-F4/R8<2.0. In an example, 1.4< F4/R7-F4/R8<1.98. The sensitivity of the fourth lens can be reduced by restricting the ratio of the effective focal length of the fourth element group to the curvature radius of the two sides of the fourth lens, so that the processing difficulty of the fourth lens is reduced.
In an exemplary embodiment, the radius of curvature R6 of the second side of the third lens, the radius of curvature R8 of the second side of the fourth lens, the center thickness CT3 of the third lens on the optical axis, the center thickness CT4 of the fourth lens on the optical axis, and the air interval T34 of the third element group and the fourth element group on the optical axis may satisfy: 15.0< (R6-R8)/(CT3+T34+CT4) <0. By controlling the conditional expressions, the sensitivity of the third lens and the fourth lens and the length of the optical system body can be effectively controlled, and miniaturization and good workability of the optical system can be ensured.
In an exemplary embodiment, the dispersion coefficient V3 of the third lens, the dispersion coefficient V4 of the fourth lens, the center thickness CT3 of the third lens on the optical axis, the center thickness CT4 of the fourth lens on the optical axis, the effective focal length F3 of the third element group, and the effective focal length F4 of the fourth element group may satisfy: 2.0< (v3×ct3+v4×ct4)/(f3+f4) <6.5. By controlling the above conditions, the dispersion coefficients of the third lens and the fourth lens can be reasonably distributed, which is beneficial to correcting chromatic aberration of the optical system; meanwhile, the focal lengths of the third lens and the fourth lens can be restrained, so that the sensitivity of the optical system is reduced, and the performance yield of the optical system is improved.
In an exemplary embodiment, the on-axis distance TD of the first side of the first element group to the second side of the fourth element group, the maximum field angle FOV of the optical system, and the total effective focal length f of the optical system may satisfy: 0.5< TD/(tan (FOV/2). Times.f) <1.5. By controlling the conditional expression, the total optical length and the corresponding image height of the optical system can be respectively in a reasonable range, so that the optical system can meet the characteristics of miniaturization and small image height.
In an exemplary embodiment, the radius of curvature R5 of the first side of the third lens, the radius of curvature R6 of the second side of the third lens, and the effective focal length F3 of the third element group may satisfy: 2.0< |R5+R6|/F3. In an example, 2.0< |r5+r6|/f3<833.0, further 10.0< |r5+r6|/f3<80.0. The sensitivity of the third lens can be reduced by limiting the ratio of the sum of the curvature radiuses of the first side surface and the second side surface of the third lens to the effective focal length of the third element group within a certain range, and the processing difficulty of the third lens is further reduced.
In an exemplary embodiment, the effective focal length F3 of the third element group, the effective focal length F4 of the fourth lens group, the air interval T34 of the third element group and the fourth element group on the optical axis, the refractive index N3 of the third lens, the refractive index N4 of the fourth lens, and the total effective focal length F of the optical system may satisfy: 0.2mm < (F3×T34/N3+F4×T34/N4)/F <2.0mm. In examples, 0.5 mm.ltoreq.F3×T34/N3+F4×T34/N4)/F <1.6mm. By controlling the conditional expression, the focal power of the optical system can be reasonably distributed, and the reasonable air interval of the third element group and the fourth element group on the optical axis is matched, so that the sensitivity of the optical system is reduced, and the performance yield of the optical system is improved.
In an exemplary embodiment, the effective focal length F1 of the first element group and the total effective focal length F of the optical system may satisfy: F1/F <2.0. In an example, 0.5< f1/f <1.5. The ratio of the effective focal length of the first element group to the total effective focal length of the optical system is restrained, so that the optical power of the optical system is reasonably distributed, and the first lens is ensured to have larger light bending capacity.
In an exemplary embodiment, the effective focal length F3 of the third element group and the total effective focal length F of the optical system may satisfy: 0< F3/f <20.0. In an example, 1.0< F3/f <15.0. The ratio of the effective focal length of the third element group to the total effective focal length of the optical system is restrained, so that the optical power of the optical system is reasonably distributed, and the third lens is guaranteed to have better light transition capability.
In an exemplary embodiment, the effective focal length F4 of the fourth element group and the total effective focal length F of the optical system may satisfy: 0< F4/f <10.0. In an example, 1.0< F4/f <6.0. The ratio of the effective focal length of the fourth element group to the total effective focal length of the optical system is restrained, so that the optical power of the optical system is reasonably distributed, and the fourth lens is guaranteed to have better light transition capability.
In an exemplary embodiment, a center thickness CTR of the reflective polarizing element on the optical axis, a center thickness CTQ1 of the first quarter-wave plate on the optical axis, a center thickness CT1 of the first lens on the optical axis, an abbe number VR of the reflective polarizing element, an abbe number VQ1 of the first quarter-wave plate, an abbe number V1 of the first lens, and an effective focal length F1 of the first element group may satisfy: 40.0< (CTR+CTQ1+CT1) × (VR+VQ1+V1)/F1 <70.0. The central thicknesses of the reflective polarizing element, the first quarter wave plate and the first lens on the optical axis are reasonably configured, and the ratio of the sum of the central thicknesses of the reflective polarizing element, the first quarter wave plate and the first lens on the optical axis to the effective focal length of the first element group is in a certain range, so that the focal length of the optical system can be effectively restrained.
In an exemplary embodiment, the refractive index NR of the reflective polarizing element, the refractive index NQ1 of the first quarter wave plate, the refractive index N1 of the first lens, the refractive index N2 of the second lens, the radius of curvature R2 of the second side surface of the first lens, and the effective focal length F1 of the first element group may satisfy: -5.0< (nr+nq1) ×r2/((n1+n2) ×f1) <0. By controlling the conditional expression, the incidence angle of light on the first quarter wave plate and the reflective polarizing element is reduced, and the angle effect of the first quarter wave plate is reduced.
In an exemplary embodiment, the maximum effective half caliber DT31 of the first side of the third lens, the maximum effective half caliber DT42 of the second side of the fourth lens, the radius of curvature R6 of the second side of the third lens, and the radius of curvature R8 of the second side of the fourth lens may satisfy: (dt31+dt42)/| (r6+r8) | <1.0. Through controlling the conditional expression, the maximum effective half caliber of the first side surface of the third lens and the maximum effective half caliber of the second side surface of the fourth lens can be restrained, the view angle of the optical system is further limited, and meanwhile, the reasonable curvature radiuses of the second side surfaces of the third lens and the fourth lens are matched, so that the third lens and the fourth lens have reasonable focal power and good forming capability, and the forming difficulty of the optical system is reduced.
In an exemplary embodiment, the radius of curvature R2 of the second side of the first lens, the maximum effective half-caliber DT12 of the second side of the first lens, and the maximum effective half-caliber DT21 of the first side of the second lens may satisfy: -2.0< R2/(DT 12+ DT 21) < -1.0. By controlling the conditional expression, the focal power of the first lens, the maximum effective half-caliber of the second side surface of the first lens and the maximum effective half-caliber of the second lens can be restrained, and the view angle of the optical system is further limited, so that the optical system is ensured to have the first lens with a larger view angle and good light collecting capability.
The optical system according to the above embodiment of the present application may employ a plurality of lenses, for example, four lenses as described above. By reasonably distributing the parameters of the reflective polarizing element, the first quarter wave plate and each lens, the length of the body of the optical system can be reduced, and the processability and imaging quality of the optical system can be improved. The optical system with the configuration has the characteristics of miniaturization, low sensitivity, 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 fourth 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.
However, those skilled in the art will appreciate that the number of lenses making up an optical system can be varied to achieve the various results and advantages described in this specification without departing from the scope of the application as claimed.
Referring to fig. 1 and 2, a second aspect of the present application provides an optical system that may include a first element group, a second element group, a third element group, and a fourth element group sequentially arranged from a first side to a second side along an optical axis. The first element group may include, for example, a first lens, a reflective polarizing element, and a first quarter wave plate. The second element group may for example comprise a second lens and a second quarter wave plate. The third element group may, for example, include a third lens. The fourth element group may include, for example, a fourth lens. Adjacent ones of the first through fourth element groups may have an air space therebetween.
Wherein the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens, and the on-axis distance TD between the first side of the first element group and the second side of the fourth element group, the maximum field angle FOV of the optical system, and the total effective focal length f of the optical system may satisfy: 0.5< TD/(tan (FOV/2). Times.f) <1.5. The optical system provided by the application adopts a plane film pasting mode to attach the reflective polarizing element and/or the first quarter wave plate on a plane, so that the quality of the reflective polarizing element and/or the first quarter wave plate after being attached can be ensured, the system performance is ensured, and simultaneously, the optical total length and the corresponding image height of the optical system are respectively in a reasonable range by restraining the axial distance from the first side surface of the first element group to the second side surface of the fourth element group, the maximum field angle of the optical system and the total effective focal length of the optical system, so that the optical system can simultaneously meet the characteristics of miniaturization and small image height.
Referring to fig. 1 and 2, a third aspect of the present application provides an optical system that may include a first element group, a second element group, a third element group, and a fourth element group sequentially arranged from a first side to a second side along an optical axis. The first element group may include, for example, a first lens, a reflective polarizing element, and a first quarter wave plate. The second element group may for example comprise a second lens and a second quarter wave plate. The third element group may, for example, include a third lens. The fourth element group may include, for example, a fourth lens. Adjacent ones of the first through fourth element groups may have an air space therebetween.
Wherein the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens, and the radius of curvature R6 of the second side of the third lens, the radius of curvature R8 of the second side of the fourth lens, the center thickness CT3 of the third lens on the optical axis, the center thickness CT4 of the fourth lens on the optical axis, and the air space T34 of the third element group and the fourth element group on the optical axis may satisfy: 15.0< (R6-R8)/(CT3+T34+CT4) <0. The optical system provided by the application adopts a plane film pasting mode to attach the reflective polarizing element and/or the first quarter wave plate on a plane, so that the quality of the reflective polarizing element and/or the first quarter wave plate after being attached can be ensured, the system performance is ensured, and simultaneously, the sensitivity of the third lens and the fourth lens and the length of the optical system body can be effectively controlled by restricting the center thickness and the surface type of the third lens and the fourth lens and the axial spacing of the third element group and the fourth element group, and the miniaturization and the good processability of the optical system are ensured.
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. 3 to 4C.
As shown in fig. 3, the optical system 100 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along an optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is concave and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 the basic parameter table of the optical system of example 1, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
TABLE 1
In embodiment 1, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-eye side S8 and the near-display side S9 of the third lens E3, the near-eye side S10 and the near-display side S11 of the fourth lens E4 are all aspherical surfaces, and the surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:
wherein x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c=1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the aspherical i-th order. Table 2 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S4, S7-S11 in example 1 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 4.3289E-01 2.1686E-02 -2.7449E-02 -4.8581E-03 2.0575E-03 5.2862E-04 1.5030E-04
S7 2.4267E+00 -2.4943E+00 8.6225E-01 -1.1198E-01 -1.8058E-02 -3.1086E-02 1.1422E-02
S8 4.9071E+00 -1.9923E+00 6.8425E-01 -2.4305E-01 3.5534E-02 -2.3509E-02 3.3611E-03
S9 1.8891E+00 7.7453E-02 -1.6507E-02 -9.4373E-02 4.5184E-02 1.8369E-03 1.5274E-02
S10 -3.1246E+00 6.0112E-01 2.5996E-01 2.3939E-01 -1.0799E-01 -8.8038E-02 -1.0118E-02
S11 7.4799E+00 -7.7532E-01 5.5241E-01 -5.6028E-01 1.6354E-01 -1.4244E-01 1.4115E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -6.7556E-04 -2.1901E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 -6.1916E-03 1.4864E-03 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 -6.0415E-04 1.2443E-02 1.0360E-03 -1.9227E-03 4.2187E-04 -1.1550E-03 4.1301E-04
S9 5.4147E-02 3.1070E-02 -1.6282E-02 -3.0189E-02 -1.3440E-02 1.3696E-02 -9.4971E-04
S10 8.0983E-02 7.1610E-02 -3.4167E-02 -7.3737E-02 -2.7814E-02 7.1817E-02 2.8273E-02
S11 -8.4386E-02 7.9492E-02 -5.5573E-02 3.8649E-02 -4.1101E-02 2.6123E-02 -6.0879E-03
TABLE 2
Fig. 4A shows an on-axis chromatic aberration curve of the optical system 100 of embodiment 1, which indicates the convergent focus deviation of light rays of different wavelengths after passing through the optical system 100. Fig. 4B shows an astigmatism curve of the optical system 100 of embodiment 1, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 4C shows a distortion curve of the optical system 100 of embodiment 1, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 4A to 4C, the optical system 100 provided in 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. 5 to 6C.
As shown in fig. 5, the optical system 200 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has positive optical power, and its near-human-eye side S6 is a plane and near-display side S7 is a convex surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is concave and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 3 shows the basic parameter table of the optical system of example 2, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
TABLE 3 Table 3
In embodiment 2, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-human eye side S8 and the near-display side S9 of the third lens E3, and the near-human eye side S10 and the near-display side S11 of the fourth lens E4 are aspherical surfaces. Table 4 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S4, S7-S11 in example 2 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 3.9555E-01 3.7287E-02 -2.4101E-02 -1.4503E-02 4.6114E-03 4.8805E-03 -2.8605E-04
S7 3.1277E+00 -2.5677E+00 9.4615E-01 1.2429E-01 1.6759E-03 -1.3656E-01 2.4581E-02
S8 5.8898E+00 -2.2942E+00 7.3693E-01 -6.0315E-02 9.5809E-02 -9.7918E-02 -2.1595E-02
S9 1.1168E+00 7.9603E-01 -2.3175E-01 -3.3070E-02 -2.7022E-01 1.9470E-01 -2.9293E-02
S10 -2.0619E+00 1.6416E+00 -3.2770E-01 1.4145E-01 -1.1040E-01 1.5952E-01 -1.6915E-01
S11 6.7642E+00 -5.3485E-01 5.1734E-01 -7.7158E-01 2.4953E-01 -6.6325E-02 1.3609E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -2.0882E-03 -1.2222E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 2.8595E-02 -3.3633E-02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 -6.8980E-03 -9.3528E-03 4.5942E-02 1.8782E-02 -1.1745E-02 -6.2689E-03 -7.8181E-04
S9 7.0963E-02 -4.2115E-02 1.0170E-01 -1.1081E-01 -5.8776E-03 2.7192E-02 -2.9826E-03
S10 4.9438E-02 3.3150E-02 9.3164E-02 -1.4933E-01 -4.7679E-02 7.0198E-02 8.0849E-03
S11 -1.6638E-01 5.5732E-02 4.9848E-02 2.3440E-02 -7.7809E-02 2.7819E-02 1.3856E-03
TABLE 4 Table 4
Fig. 6A shows an on-axis chromatic aberration curve of the optical system 200 of embodiment 2, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical system 200. Fig. 6B shows an astigmatism curve of the optical system 200 of embodiment 2, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 6C shows a distortion curve of the optical system 200 of embodiment 2, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 6A to 6C, the optical system 200 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. 7 to 8C.
As shown in fig. 7, the optical system 300 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is concave and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 5 shows the basic parameter table of the optical system of example 3, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
TABLE 5
In embodiment 3, the near display side S4 of the first lens E1, the near display side S7 of the second lens E2, the third lens E3The near-human-eye side surface S8 and the near-display side surface S9, and the near-human-eye side surface S10 and the near-display side surface S11 of the fourth lens E4 are aspherical surfaces. Table 6 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S4, S7-S11 in example 3 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 5.0634E-01 -1.2190E-03 1.2317E-02 -1.3622E-02 2.7949E-03 -2.1164E-03 1.5758E-03
S7 -2.9245E-01 -7.4404E-02 -5.0916E-02 3.8725E-02 -7.7924E-03 8.2782E-03 -5.7474E-03
S8 4.5214E+00 -8.9246E-01 4.4005E-01 -2.1158E-01 8.5724E-02 -5.4468E-02 1.6747E-02
S9 1.8477E+00 -5.6121E-01 2.0557E-01 -9.4131E-02 5.0505E-02 -3.6924E-02 9.5159E-03
S10 -3.5746E+00 1.0047E+00 -3.8688E-01 2.2027E-01 -1.0819E-01 3.9933E-02 9.5188E-03
S11 7.2500E+00 -1.3014E+00 8.1556E-01 -4.6482E-01 2.5530E-01 -1.8339E-01 1.2867E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -8.0946E-04 2.1112E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 -3.4718E-03 5.3242E-03 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 -3.2346E-03 7.7377E-03 2.9766E-03 -2.6964E-03 -1.6383E-03 -8.9498E-04 -9.7910E-04
S9 2.1668E-02 4.9109E-03 -5.3961E-03 -2.7354E-03 1.6982E-03 -3.7069E-03 1.6443E-03
S10 -2.7178E-03 1.2711E-02 -2.0912E-02 1.1726E-02 -2.7147E-03 6.3528E-04 -1.1476E-04
S11 -7.7853E-02 6.5405E-02 -5.4696E-02 3.8306E-02 -4.1027E-02 2.7785E-02 -6.4506E-03
TABLE 6
Fig. 8A shows an on-axis chromatic aberration curve of the optical system 300 of embodiment 3, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical system 300. Fig. 8B shows an astigmatism curve of the optical system 300 of embodiment 3, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 8C shows a distortion curve of the optical system 300 of embodiment 3, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 8A to 8C, the optical system 300 according to 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. 9 to 10C.
As shown in fig. 9, the optical system 400 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is convex and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 the basic parameter table of the optical system of example 4, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
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TABLE 7
In embodiment 4, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-human eye side S8 and the near-display side S9 of the third lens E3, and the near-human eye side S10 and the near-display side S11 of the fourth lens E4 are aspherical surfaces. Table 8 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S4, S7-S11 in example 4 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 3.7880E-01 -1.3276E-02 -1.9525E-02 -3.6426E-03 2.2939E-03 -2.1570E-03 -1.7314E-03
S7 4.2963E+00 -2.6099E+00 7.7483E-01 -1.6245E-01 5.9652E-02 -1.7248E-01 2.6885E-02
S8 7.0551E+00 -2.2956E+00 5.5123E-01 -3.0050E-01 1.0096E-01 -3.9728E-02 2.0227E-02
S9 1.6406E+00 3.1010E-01 -1.6278E-01 -5.5014E-02 -2.3162E-01 2.3375E-01 -5.0110E-02
S10 -3.4678E+00 4.7797E-01 -1.8923E-01 1.3875E-02 -1.4342E-01 5.0254E-02 -1.2222E-01
S11 8.4484E+00 -1.0961E+00 7.5517E-01 -7.7316E-01 1.7394E-01 -2.3457E-01 1.7794E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 5.4551E-04 8.3062E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 3.5951E-02 1.9151E-02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 1.3041E-02 4.1169E-03 3.7458E-03 3.2123E-04 6.0696E-06 -2.6117E-03 5.5614E-05
S9 8.0065E-02 -8.9831E-02 5.5650E-02 -7.3454E-02 7.0694E-03 2.9752E-02 2.4033E-02
S10 1.5115E-01 1.4108E-01 1.5007E-01 -1.0094E-01 -1.7390E-02 1.3094E-01 7.1573E-02
S11 -1.2755E-02 2.1377E-01 2.2995E-02 -8.7395E-02 -9.7813E-02 1.0335E-01 2.5634E-02
TABLE 8
Fig. 10A shows an on-axis chromatic aberration curve of the optical system 400 of embodiment 4, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical system 400. Fig. 10B shows an astigmatism curve of the optical system 400 of embodiment 4, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 10C shows a distortion curve of the optical system 400 of embodiment 4, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 10A to 10C, the optical system 400 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. 11 to 12C.
As shown in fig. 11, the optical system 500 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along an optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is convex and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 9 shows the basic parameter table of the optical system of example 5, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
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TABLE 9
In embodiment 5, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-human eye side S8 and the near-display side S9 of the third lens E3, and the near-human eye side S10 and the near-display side S11 of the fourth lens E4 are aspherical surfaces. Table 10 shows the higher order coefficients A that can be used for each of the aspherical mirror surfaces S4, S7-S11 in example 5 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 3.9853E-01 3.6868E-02 -2.3897E-02 -1.4437E-02 5.2343E-03 4.8731E-03 -4.1553E-04
S7 1.7625E+00 -2.4982E+00 8.3879E-01 9.2019E-02 3.8925E-03 -1.2092E-01 1.9140E-02
S8 5.5421E+00 -2.2720E+00 7.2018E-01 -5.5594E-02 9.8185E-02 -9.2562E-02 -1.4617E-02
S9 1.2405E+00 6.0795E-01 -1.8747E-01 -2.3203E-02 -2.5749E-01 1.8481E-01 -2.2571E-02
S10 -2.1849E+00 1.5124E+00 -2.5105E-01 1.2802E-01 -1.0776E-01 1.5629E-01 -1.6604E-01
S11 6.7664E+00 -5.6466E-01 5.3134E-01 -7.6836E-01 2.5238E-01 -6.0800E-02 1.3065E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -2.0884E-03 6.0780E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 2.5528E-02 -3.7337E-02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 1.2071E-03 -1.0614E-02 4.1488E-02 1.7877E-02 -9.5941E-03 -4.8533E-03 -2.2292E-03
S9 7.3176E-02 -4.1220E-02 9.7475E-02 -1.1009E-01 -6.8528E-03 3.2752E-02 -6.1950E-03
S10 6.2257E-02 3.7105E-02 9.0051E-02 -1.4378E-01 -4.9431E-02 6.4252E-02 7.7923E-03
S11 -1.6456E-01 5.5236E-02 4.7793E-02 2.1940E-02 -7.5710E-02 2.8269E-02 1.1505E-03
Table 10
Fig. 12A shows an on-axis chromatic aberration curve of the optical system 500 of embodiment 5, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical system 500. Fig. 12B shows an astigmatism curve of the optical system 500 of embodiment 5, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 12C shows a distortion curve of the optical system 500 of embodiment 5, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 12A to 12C, the optical system 500 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. 13 to 14C.
As shown in fig. 13, the optical system 600 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is concave and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is concave and near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 11 shows the basic parameter table of the optical system of example 6, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
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TABLE 11
In embodiment 6, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-eye side S8 and the near-display side S9 of the third lens E3, and the near-eye side S10 and the near-display side S11 of the fourth lens E4 are aspherical surfaces. Table 12 shows the higher order coefficients A that can be used for each of the aspherical mirror surfaces S4, S7-S11 in example 6 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 4.0017E-01 2.9386E-02 -2.1659E-02 -1.3859E-02 5.4608E-03 4.2744E-03 -5.5103E-04
S7 1.7575E+00 -2.4378E+00 8.2224E-01 9.0045E-02 -1.2067E-02 -1.2852E-01 1.7684E-02
S8 5.7081E+00 -2.2307E+00 7.0447E-01 -8.7826E-02 8.5295E-02 -9.7380E-02 -7.1900E-03
S9 1.2912E+00 6.4868E-01 -2.0322E-01 -4.0536E-02 -2.5076E-01 1.8791E-01 -2.0268E-02
S10 -1.1249E+00 1.4141E+00 -2.1631E-01 1.3206E-01 -9.7595E-02 1.6532E-01 -1.6258E-01
S11 6.8546E+00 -5.4365E-01 5.3568E-01 -7.6830E-01 2.5110E-01 -6.2553E-02 1.3107E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -2.0190E-03 1.7068E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 2.4864E-02 -3.3764E-02 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 2.7921E-03 1.7930E-03 4.9466E-02 1.6235E-02 -1.5635E-02 -7.7696E-03 -2.1536E-03
S9 6.7769E-02 -4.1022E-02 1.0253E-01 -1.1052E-01 -9.7613E-03 3.0456E-02 -4.1535E-03
S10 5.8768E-02 3.5340E-02 9.5911E-02 -1.4360E-01 -5.1471E-02 6.3893E-02 5.5005E-03
S11 -1.6520E-01 5.5943E-02 4.8244E-02 2.2513E-02 -7.6176E-02 2.8475E-02 1.0187E-03
Table 12
Fig. 14A shows an on-axis chromatic aberration curve of the optical system 600 of example 6, which represents the convergent focus deviation of light rays of different wavelengths after passing through the optical system 600. Fig. 14B shows an astigmatism curve of the optical system 600 of embodiment 6, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 14C shows a distortion curve of the optical system 600 of example 6, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 14A to 14C, the optical system 600 provided in embodiment 6 can achieve good imaging quality.
Example 7
An optical system according to embodiment 7 of the present application is described below with reference to fig. 15 to 16C.
As shown in fig. 15, the optical system 700 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative optical power, and its near-human-eye side S5 is concave and near-display side S6 is plane. The second quarter wave plate QWP2 has a near-eye side and a near-display side S7, which is attached to the near-display side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is convex and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is concave.
In this example, the second side of the optical system may be provided with an image surface S13, the image surface S13 may be provided with a display, for example, and the display has a near-human eye side surface S12. After the image light from the display passes through the fourth lens E4, the third lens E3, the second quarter wave plate QWP2, the second lens E2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 13 shows the basic parameter table of the optical system of example 7, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 19 to number 2 and is finally projected into the human eye.
TABLE 13
In example 7, the near-display side S4 of the first lens E1 and the near-human eye side of the second lens E2The surface S5, the near-eye side surface S8 and the near-display side surface S9 of the third lens E3, and the near-eye side surface S10 and the near-display side surface S11 of the fourth lens E4 are aspherical surfaces. Table 14 shows the higher order coefficients A that can be used for each of the aspherical mirror surfaces S4, S5, S8-S11 in example 7 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 And A 26 。
Face number A4 A6 A8 A10 A12 A14
S4 9.6484E-01 -5.8118E-02 -3.2365E-04 7.4224E-03 -1.0168E-03 -4.2892E-04
S5 7.4019E+00 -7.8154E-01 -8.4200E-03 -1.5451E-04 -3.3709E-06 -7.8549E-08
S8 3.3033E+00 6.0722E-01 -2.0580E-01 -6.8298E-02 -3.8919E-02 -3.5035E-02
S9 1.0171E+01 -1.1613E+00 -2.5638E-02 -2.0548E-01 8.7486E-02 -6.0957E-03
S10 -9.8505E-01 -1.0561E+00 1.3011E+00 -1.3150E-01 -2.0505E-01 6.1989E-02
S11 -2.6504E+00 8.0567E-01 4.2812E-01 6.0392E-02 -2.0704E-01 -1.9349E-02
Face number A16 A18 A20 A22 A24 A26
S4 -3.0269E-04 -7.8223E-04 -1.3914E-05 0.0000E+00 0.0000E+00 0.0000E+00
S5 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 5.4610E-03 4.0733E-03 1.9025E-03 -2.1165E-04 -1.3373E-05 -6.1046E-07
S9 9.4747E-04 5.6004E-03 -2.2649E-03 -2.2624E-05 -1.9802E-07 0.0000E+00
S10 3.1263E-02 -1.5201E-03 -9.2811E-03 -3.3584E-05 1.8998E-06 1.1990E-07
S11 -3.6326E-02 2.9973E-02 3.6279E-03 2.4197E-06 0.0000E+00 0.0000E+00
TABLE 14
Fig. 16A shows an on-axis chromatic aberration curve of the optical system 700 of embodiment 7, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the optical system 700. Fig. 16B shows an astigmatism curve of the optical system 700 of embodiment 7, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 16C shows a distortion curve of the optical system 700 of embodiment 7, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 16A to 16C, the optical system 700 provided in embodiment 7 can achieve good imaging quality.
Example 8
An optical system according to embodiment 8 of the present application is described below with reference to fig. 17 to 18C.
As shown in fig. 17, the optical system 800 includes a first element group, a second element group, a third element group, and a fourth element group, which are sequentially arranged from a first side to a second side along the optical axis. The first element group includes a first lens E1, a reflective polarizing element RP, and a first quarter wave plate QWP1, and in other examples, the first element group further includes a partially reflective layer BS (not shown). The second element group includes a second lens E2 and a second quarter wave plate QWP2. The third element group includes a third lens E3. The fourth element group includes a fourth lens E4. In this embodiment, the first side refers to the human eye side and the second side refers to the display side. The first side of each element (first lens E1, second lens E2, third lens E3, fourth lens E4, reflective polarizing element RP, first quarter wave plate QWP1 and second quarter wave plate QWP 2) is referred to as the near-eye side, and the second side is referred to as the near-display side.
The first lens E1 has positive optical power, its near-human-eye side surface S3 is a plane, the near-display side surface S4 is a convex surface, and a partially reflective layer BS is attached. The reflective polarizing element RP has a near-eye side S1 and a near-display side, the first quarter wave plate QWP1 has a near-eye side S2 and a near-display side, the near-display side of the reflective polarizing element RP is attached to the near-eye side S2 of the first quarter wave plate QWP1, and the near-display side of the first quarter wave plate QWP1 is attached to the near-eye side S3 of the first lens E1. The second lens E2 has negative power, and its near-eye side S6 is a plane and near-display side S7 is a concave surface. The second quarter wave plate QWP2 has a near-eye side S5 and a near-display side, which is attached to the near-eye side S6 of the second lens E2. The third lens E3 has positive power, and its near-eye side S8 is concave and near-display side S9 is convex. The fourth lens E4 has positive power, and its near-eye side S10 is convex and its near-display side S11 is convex.
In this example, the second side of the optical system may be provided with an image surface S14, and the image surface S14 may be provided with a display, for example. The optical system further comprises a third quarter wave plate QWP3, the third quarter wave plate QWP3 having a near-eye side S12 and a near-display side, the near-display side being attached to the near-eye side S13 of the display. After the image light from the display passes through the fourth lens E4, the third lens E3, the second lens E2, the second quarter wave plate QWP2, the first lens E1, the first quarter wave plate QWP1 in order and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the first quarter wave plate QWP1, the first lens E1, and reaches the partially reflective layer BS, the second reflection occurs at the partially reflective layer BS. The light reflected the second time passes through the first lens E1, the first quarter wave plate QWP1, the reflective polarizing element RP, 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 15 shows the basic parameter table of the optical system of example 8, in which the unit of radius of curvature, thickness/distance is millimeter (mm). Image light from the display passes through the elements in the order of number 20 to number 2 and is finally projected into the human eye.
TABLE 15
In example 8, the near-display side S4 of the first lens E1, the near-display side S7 of the second lens E2, the near-eye side S8 and the near-display side S9 of the third lens E3, and the near-eye side S10 and the near-display side S11 of the fourth lens E4 are aspherical surfaces. Table 16 shows the higher order coefficients A that can be used for each of the aspherical mirror surfaces S4, S7-S11 in example 8 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 、A 20 、A 22 、A 24 、A 26 、A 28 And A 30 。
Face number A4 A6 A8 A10 A12 A14 A16
S4 5.0634E-01 -1.2190E-03 1.2317E-02 -1.3622E-02 2.7949E-03 -2.1164E-03 1.5758E-03
S7 -2.9245E-01 -7.4404E-02 -5.0916E-02 3.8725E-02 -7.7924E-03 8.2782E-03 -5.7474E-03
S8 4.5214E+00 -8.9246E-01 4.4005E-01 -2.1158E-01 8.5724E-02 -5.4468E-02 1.6747E-02
S9 1.8477E+00 -5.6121E-01 2.0557E-01 -9.4131E-02 5.0505E-02 -3.6924E-02 9.5159E-03
S10 -3.5746E+00 1.0047E+00 -3.8688E-01 2.2027E-01 -1.0819E-01 3.9933E-02 9.5188E-03
S11 7.2500E+00 -1.3014E+00 8.1556E-01 -4.6482E-01 2.5530E-01 -1.8339E-01 1.2867E-01
Face number A18 A20 A22 A24 A26 A28 A30
S4 -8.0946E-04 2.1112E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S7 -3.4718E-03 5.3242E-03 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00
S8 -3.2346E-03 7.7377E-03 2.9766E-03 -2.6964E-03 -1.6383E-03 -8.9498E-04 -9.7910E-04
S9 2.1668E-02 4.9109E-03 -5.3961E-03 -2.7354E-03 1.6982E-03 -3.7069E-03 1.6443E-03
S10 -2.7178E-03 1.2711E-02 -2.0912E-02 1.1726E-02 -2.7147E-03 6.3528E-04 -1.1476E-04
S11 -7.7853E-02 6.5405E-02 -5.4696E-02 3.8306E-02 -4.1027E-02 2.7785E-02 -6.4506E-03
Table 16
Fig. 18A shows an on-axis chromatic aberration curve of the optical system 800 of embodiment 8, which represents the deviation of the converging focus of light rays of different wavelengths after passing through the optical system 800. Fig. 18B shows an astigmatism curve of the optical system 800 of embodiment 8, which represents a meridional image surface curvature and a sagittal image surface curvature corresponding to different angles of view. Fig. 18C shows a distortion curve of the optical system 800 of embodiment 8, which represents distortion magnitude values corresponding to different angles of view. As can be seen from fig. 18A to 18C, the optical system 800 provided in embodiment 8 can achieve good imaging quality.
Table 17 gives the values of the basic parameters of each of examples 1 to 8.
Condition/example 1 2 3 4 5 6 7 8
f(mm) 14.06 13.94 13.95 14.27 13.96 14.06 20.80 13.95
F1(mm) 15.44 15.26 15.58 16.06 15.25 15.18 15.17 15.58
F2(mm) -242.13 10000.00 -2235.80 -236.97 -240.29 -240.16 -112.58 -2235.80
F3(mm) 89.03 57.17 192.88 86.27 54.18 44.30 33.96 192.88
F4(mm) 22.23 22.61 20.61 17.15 21.38 24.52 118.59 20.61
FOV(°) 110.0 110.0 100.0 86.0 110.0 110.0 110.0 110.0
EPD(mm) 5.00 5.00 4.00 5.00 5.00 5.00 5.00 5.00
TABLE 17
In summary, table 18 shows the values of the conditional expressions of each of examples 1 to 8.
Condition/example 1 2 3 4 5 6 7 8
TD/f 1.18 1.19 1.17 1.26 1.19 1.18 0.86 1.17
CT3/((N2+N3)×T23) 9.17 11.76 9.29 11.31 11.62 11.66 11.40 9.29
(T23+CT2+CT3)×(V2+V3)/|(F2+F3)| 3.62 0.06 0.26 4.25 3.42 3.30 8.77 0.26
R2/((CT1+T12+CT2)×(N1+N2)) -2.22 -2.21 -2.15 -2.35 -2.21 -2.20 -1.72 -2.15
(R5-R6)/(R5+R6) 0.93 0.72 0.64 1.03 1.00 0.93 1.02 0.64
F4/R7-F4/R8 1.89 1.47 1.90 1.50 1.48 1.47 1.96 1.90
(R6-R8)/(CT3+T34+CT4) -3.43 -1.03 -7.88 -3.04 -1.36 -0.71 -14.17 -7.88
(V3×CT3+V4×CT4)/(F3+F4) 4.28 5.22 2.09 4.25 5.45 6.04 2.05 2.09
TD/(tan(FOV/2)×f) 0.83 0.83 0.98 1.35 0.83 0.83 0.60 0.82
|R5+R6|/F3 14.30 3.19 2.39 33.84 832.08 15.89 78.60 2.39
(F3×T34/N3+F4×T34/N4)/f 0.82 0.58 1.59 0.75 0.55 0.50 1.31 1.59
F1/f 1.10 1.09 1.12 1.13 1.09 1.08 0.73 1.12
F3/f 6.33 4.10 13.82 6.05 3.88 3.15 1.63 13.82
F4/f 1.58 1.62 1.48 1.20 1.53 1.74 5.70 1.48
(CTR+CTQ1+CT1)×(VR+VQ1+V1)/F1 64.64 64.93 67.02 61.10 64.87 65.27 46.57 67.02
(NR+NQ1)×R2/((N1+N2)×F1) -3.09 -3.09 -3.08 -3.10 -3.09 -3.09 -3.32 -3.08
(DT31+DT42)/|(R6+R8)| 0.47 0.68 0.29 0.40 0.63 0.73 0.48 0.30
R2/(DT12+DT21) -1.37 -1.36 -1.46 -1.80 -1.36 -1.35 -1.35 -1.29
TABLE 18
The present application also provides an optical apparatus, which 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 virtual reality device. The optical device is equipped with the optical system described above.
The above description is only illustrative of the preferred embodiments of the present application and of the principles of the technology employed. It will be appreciated by persons skilled in the art that the scope of the application referred to in the present application 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 application (but not limited to) having similar functions 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 element group including a first lens, a reflective polarizing element, and a first quarter wave plate;
a second element group including a second lens and a second quarter wave plate;
a third element group including a third lens;
A fourth element group including a fourth lens;
wherein the first side of the first lens is configured as a plane, and the reflective polarizing element and/or the first quarter wave plate is attached to the first side of the first lens, and
an on-axis distance TD from the first side of the first element group to the second side of the fourth element group and a total effective focal length f of the optical system satisfy: TD/f <1.5.
2. The optical system according to claim 1, wherein a center thickness CT3 of the third lens on the optical axis, a refractive index N2 of the second lens, a refractive index N3 of the third lens, and an air interval T23 of the second element group and the third element group on the optical axis satisfy: 8.0< CT3/((N2+N3). Times.T23) <12.0.
3. The optical system according to claim 1, wherein a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, an air interval T23 of the second element group and the third element group on the optical axis, an abbe number V2 of the second lens, an abbe number V3 of the third lens, an effective focal length F2 of the second element group, and an effective focal length F3 of the third element group satisfy: (t23+ct2+ct3) × (v2+v3)/| (f2+f3) | <10.0.
4. The optical system of claim 1, wherein the maximum field angle FOV of the optical system satisfies: 80 ° < FOV <120 °.
5. The optical system according to claim 1, wherein a radius of curvature R2 of the second side surface of the first lens, a center thickness CT1 of the first lens on the optical axis, a center thickness CT2 of the second lens on the optical axis, an air interval T12 of the first element group and the second element group on the optical axis, a refractive index N1 of the first lens, and a refractive index N2 of the second lens satisfy: -3.0< r 2/((CT 1+ T12+ CT 2) × (N1 + N2)) <0.
6. The optical system of claim 1, wherein a radius of curvature R5 of the first side of the third lens and a radius of curvature R6 of the second side of the third lens satisfy: 0.2< (R5-R6)/(R5+R6) <1.5.
7. The optical system of claim 1, wherein a radius of curvature R7 of the first side of the fourth lens, a radius of curvature R8 of the second side of the fourth lens, and an effective focal length F4 of the fourth element group satisfy: 0< F4/R7-F4/R8<2.0.
8. The optical system according to claim 1, wherein a radius of curvature R6 of the second side surface of the third lens, a radius of curvature R8 of the second side surface of the fourth lens, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis, and an air interval T34 of the third element group and the fourth element group on the optical axis satisfy: 15.0< (R6-R8)/(CT3+T34+CT4) <0.
9. The optical system according to claim 1, wherein an abbe number V3 of the third lens, an abbe number V4 of the fourth lens, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis, an effective focal length F3 of the third element group, and an effective focal length F4 of the fourth element group satisfy: 2.0< (v3×ct3+v4×ct4)/(f3+f4) <6.5.
10. The optical system of claim 1 or 4, wherein an on-axis distance TD from a first side of the first element group to a second side of the fourth element group, a maximum field angle FOV of the optical system, and a total effective focal length f of the optical system satisfy: 0.5< TD/(tan (FOV/2). Times.f) <1.5.
CN202310980758.5A 2023-08-04 2023-08-04 Optical system Pending CN116880046A (en)

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