CN117806034A - Optical system and VR device including the same - Google Patents
Optical system and VR device including the same Download PDFInfo
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- CN117806034A CN117806034A CN202311873821.1A CN202311873821A CN117806034A CN 117806034 A CN117806034 A CN 117806034A CN 202311873821 A CN202311873821 A CN 202311873821A CN 117806034 A CN117806034 A CN 117806034A
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Abstract
The application discloses an optical system and VR device including the optical system. The optical system sequentially comprises from a first side to a second side along the optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having positive optical power, the first side of which is concave and the second side of which is convex. The optical system further includes a reflective polarizing element and a quarter wave plate attached to the first side or the second side of the first lens. The effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate satisfy 0.04< f/fz <0.16; the effective half-caliber T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile of the first side surface of the first lens, the effective half-caliber T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens, and the effective focal length f of the optical system meet 1.5< (T1a1+T1c1)/f <2.2.
Description
Technical Field
The present application relates to the field of optical elements, and more particularly, to an optical system and VR device including the same.
Background
With the proposal of the concept of "meta-universe", virtual reality technology (VR) has also gradually moved into people's lives. Based on the technical fusion of multiple aspects such as computer algorithm, graphic processing, optical display and the like, the three-dimensional dynamic view is gradually established and has an interaction function. On the one hand, the VR device not only better meets the practical requirements of life of people, but also greatly increases the comfort of use; on the other hand, in the early days, the aspherical surface or the fresnel lens body was long, which resulted in the VR device having a front center of gravity, and thus the user experience was poor, and a return type optical system was proposed.
The foldback optical system is folded through the light path, so that the length of the whole lens can be compressed to a great extent, the center of gravity of the VR device is moved backwards, and the use comfort of consumers is further improved. However, the current folded optical system still needs to further reduce the size and weight, and further improve the experience of the user, so as to meet the high requirements of the market and consumers. For a three-piece refractive-reflective optical system, those skilled in the art expect to optimize the optical parameters of the first lens on the side closest to the user or the side closest to the human eye, so as to further improve the control of the light exit angle, ensure the outer diameter size and the processability thereof, reduce the system volume and further improve the immersive experience of the user.
Disclosure of Invention
The application provides an optical system, can include in order from first side to second side along the optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having positive optical power, the first side of which is concave and the second side of which is convex; the optical system further includes: and the reflective polarizing element and the quarter wave plate are attached to the first side or the second side of the first lens. The optical system can satisfy: 0.04< f/fz <0.16 and 1.5< (t1a1+t1c1)/f <2.2, where f is an effective focal length of the optical system, fz is a combined focal length of the first lens, the reflective polarizing element, and the quarter wave plate, T1a1 is an effective half caliber from an optical center of a first side of the first lens to an upper edge of an effective diameter profile of the first side of the first lens, and T1c1 is an effective half caliber from an optical center of the first side of the first lens to a lower edge of the effective diameter profile of the first side of the first lens.
In one embodiment, an effective half-caliber T1b1 from an optical center of the first side surface of the first lens to a left edge of an effective diameter profile of the first side surface of the first lens and a center thickness CT1 of the first lens on the optical axis may satisfy: 2.7< T1b1/CT1<4.7.
In one embodiment, the effective focal length f1 of the first lens, the optical center of the second side of the first lens, the effective half-caliber T1a2 of the upper edge of the effective diameter profile of the second side of the first lens, the optical center of the second side of the first lens, the effective half-caliber T1b2 of the left edge of the effective diameter profile of the second side of the first lens, the effective half-caliber T1c2 of the lower edge of the effective diameter profile of the second side of the first lens, and the effective half-caliber T1d2 of the optical center of the second side of the first lens, the effective half-caliber of the right edge of the effective diameter profile of the second side of the first lens may satisfy: 1.6< f 1/(t1a2+t1b2+t1c2+t1d2) <6.1.
In one 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 center thickness CT1 of the first lens on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis may satisfy: 1.1< (CT2+CT3)/(CT1+CTR+CTQ) <2.0.
In one embodiment, the entrance pupil diameter EPD of the optical system may satisfy: 3.1< T1a1/EPD <4.3.
In one embodiment, the distance TD on the optical axis between the optical center of the first side of the first lens and the left edge of the effective diameter profile of the first side of the first lens, between the optical center of the first side of the first lens and the right edge of the effective diameter profile of the first side of the first lens, and between the first side of the first lens and the second side of the third lens may be as follows: 2.0< (T1b1+T1d1)/TD <3.2.
In one embodiment, the refractive index N1 of the first lens and the effective half-caliber T1d1 from the optical center of the first side surface of the first lens to the right edge of the effective diameter profile of the first side surface of the first lens may satisfy: 1.1< N1× (T1 a1/T1d 1) <1.4.
In one embodiment, an effective half-aperture T1a2 from an optical center of the second side of the first lens to an upper edge of an effective diameter profile of the second side of the first lens, an effective half-aperture T1c2 from an optical center of the second side of the first lens to a lower edge of an effective diameter profile of the second side of the first lens, and a maximum half field angle Semi-FOV of the optical system may satisfy: 1.5< (T1a2+T1c2)/(f×tan (Semi-FOV)) <2.0.
In one embodiment, the effective focal length f3 of the third lens, 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: -4.8< f 3/(R5+R6) < -0.1.
In one embodiment, the radius of curvature R4 of the second side of the second lens and the effective focal length f2 of the second lens may satisfy: -1.1< R4/f2< -0.1.
In one embodiment, the refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective half-caliber T1b2 from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens may satisfy: 18.2mm < (NR/NQ). Times.T1b2 <23.3mm.
In another aspect, the present application further provides an optical system, which may include, in order from a first side to a second side along an optical axis: a first lens having positive optical power; a second lens having positive optical power, the second side of which is convex; and a third lens having positive optical power, the first side of which is concave and the second side of which is convex; the optical system may further include: and the reflective polarizing element and the quarter wave plate are attached to the first side or the second side of the first lens. The optical system may satisfy 0.04< f/fz <0.16 and 3.1< T1a1/EPD <4.3, where f is an effective focal length of the optical system, fz is a combined focal length of the first lens, the reflective polarizing element, and the quarter wave plate, T1a1 is an effective half-caliber from an optical center of a first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens, and EPD is an entrance pupil diameter of the optical system.
In one embodiment, an effective half-caliber T1b1 from an optical center of the first side surface of the first lens to a left edge of an effective diameter profile of the first side surface of the first lens and a center thickness CT1 of the first lens on the optical axis may satisfy: 2.7< T1b1/CT1<4.7.
In one embodiment, the effective focal length f1 of the first lens, the optical center of the second side of the first lens, the effective half-caliber T1a2 of the upper edge of the effective diameter profile of the second side of the first lens, the optical center of the second side of the first lens, the effective half-caliber T1b2 of the left edge of the effective diameter profile of the second side of the first lens, the effective half-caliber T1c2 of the lower edge of the effective diameter profile of the second side of the first lens, and the effective half-caliber T1d2 of the optical center of the second side of the first lens, the effective half-caliber of the right edge of the effective diameter profile of the second side of the first lens may satisfy: 1.6< f 1/(t1a2+t1b2+t1c2+t1d2) <6.1.
In one 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 center thickness CT1 of the first lens on the optical axis, the center thickness CTR of the reflective polarizing element on the optical axis, and the center thickness CTQ of the quarter-wave plate on the optical axis may satisfy: 1.1< (CT2+CT3)/(CT1+CTR+CTQ) <2.0.
In one embodiment, an effective half-caliber T1c1 from an optical center of the first side of the first lens to a lower edge of an effective diameter profile of the first side of the first lens may satisfy: 1.5< (T1a1+T1c1)/f <2.2.
In one embodiment, the distance TD on the optical axis between the optical center of the first side of the first lens and the left edge of the effective diameter profile of the first side of the first lens, between the optical center of the first side of the first lens and the right edge of the effective diameter profile of the first side of the first lens, and between the first side of the first lens and the second side of the third lens may be as follows: 2.0< (T1b1+T1d1)/TD <3.2.
In one embodiment, the refractive index N1 of the first lens and the effective half-caliber T1d1 from the optical center of the first side surface of the first lens to the right edge of the effective diameter profile of the first side surface of the first lens may satisfy: 1.1< N1× (T1 a1/T1d 1) <1.4.
In one embodiment, an effective half-aperture T1a2 from an optical center of the second side of the first lens to an upper edge of an effective diameter profile of the second side of the first lens, an effective half-aperture T1c2 from an optical center of the second side of the first lens to a lower edge of an effective diameter profile of the second side of the first lens, and a maximum half field angle Semi-FOV of the optical system may satisfy: 1.5< (T1a2+T1c2)/(f×tan (Semi-FOV)) <2.0.
In one embodiment, the effective focal length f3 of the third lens, 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: -4.8< f 3/(R5+R6) < -0.1.
In one embodiment, the radius of curvature R4 of the second side of the second lens and the effective focal length f2 of the second lens may satisfy: -1.1< R4/f2< -0.1.
In one embodiment, the refractive index NR of the reflective polarizing element, the refractive index NQ of the quarter-wave plate, and the effective half-caliber T1b2 from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens may satisfy: 18.2mm < (NR/NQ). Times.T1b2 <23.3mm.
In yet another aspect, the present application further provides a VR device, where the VR device includes an optical system provided in any one of the foregoing embodiments, and the first side is a human eye side and the second side is a display side.
The optical system comprises a first lens with positive focal power, a second lens with positive focal power and a third lens with positive focal power sequentially from a first side to a second side along an optical axis, wherein the second side surface of the second lens is a convex surface, the first side surface of the third lens is a concave surface, the second side surface is a convex surface, and a reflective polarizing element and a quarter wave plate are attached to the first side or the second side of the first lens. The optical system has a positive and positive optical architecture, and simultaneously controls the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate to meet 0.04< f/fz <0.16, under the precondition, the control of the light emergent angle of the first lens can be facilitated by controlling the effective half caliber T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile, the effective half caliber T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile and the effective focal length f of the optical system to meet 1.5< (T1a1+T1c1)/f < 2.2.
Drawings
Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:
fig. 1 shows a schematic configuration diagram of an optical system according to embodiment 1, embodiment 2, and embodiment 3 of the present application;
fig. 2, 3 and 4 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 1, example 2 and example 3, respectively;
fig. 5 shows a schematic structural view of an optical system according to embodiment 4, embodiment 5, and embodiment 6 of the present application;
fig. 6, 7 and 8 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 4, example 5 and example 6, respectively;
fig. 9 shows a schematic structural view of an optical system according to embodiment 7, embodiment 8, and embodiment 9 of the present application;
fig. 10, 11 and 12 show on-axis chromatic aberration curves, astigmatism curves and distortion curves of the optical systems of example 7, example 8 and example 9, respectively;
FIG. 13 shows a schematic view of the effective half-aperture in the a1, b1, c1, d1 directions of the first side of the first lens in an optical system according to an exemplary embodiment of the present application; and
Fig. 14 shows a schematic view of the effective half aperture in the a2, b2, c2, d2 direction of the second side of the first lens in the optical system according to the exemplary embodiment of the present application.
Detailed Description
For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of exemplary embodiments of the application and are not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
It should be noted that in this specification, the expressions first, second, etc. are only used to distinguish one feature from another feature, and do not represent any limitation of the feature. Accordingly, a first optical lens discussed below may also be referred to as a second optical lens, and a second optical lens may also be referred to as a first optical lens, without departing from the teachings of the present application.
In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.
Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.
It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the present application, use of "may" means "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The features, principles, and other aspects of the present application are described in detail below.
The optical system according to the exemplary embodiment of the present application may include a first lens, a second lens, and a third lens sequentially arranged from a first side to a second side along the optical axis, wherein the first lens may have positive optical power, the second lens may have positive optical power, and the third lens may have positive optical power.
In an exemplary embodiment, the second side of the second lens may be convex. The first side of the third lens may be concave and the second side may be convex.
In an exemplary embodiment, the optical system may further include a reflective polarizing element and a quarter wave plate. The reflective polarizing element and the quarter wave plate may be attached to the first side or the second side of the first lens.
In an exemplary embodiment, the first side may be, for example, a human eye side, and the second side may be, for example, a display side. The optical system may be used for VR devices, for example.
An optical system will be exemplarily described below with reference to fig. 1. As shown in fig. 1, the optical system according to the exemplary embodiment of the present application may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, and a partially reflective element BS, which are sequentially arranged from a first side to a second side, wherein the reflective polarizing element RP and the quarter wave plate QWP are attached to the second side of the first lens. In actual use, the optical system according to the exemplary embodiment of the present application may be used as a VR lens, in which case the first side corresponds to the human eye side and the second side corresponds to the display side. The optical system may also include an image plane IMG on a second side (e.g., display side). The light beam emitted from the image plane IMG may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the third lens E3, the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit toward the first side (e.g., the human eye side). In an exemplary embodiment, the partially reflective element BS may be a semi-transparent and semi-reflective film layer plated on the second side or the first side of the third lens E3.
In an exemplary embodiment, the effective half-caliber of the first side surface of the first lens in the a1, b1, c1, d1 directions is as shown in fig. 13, specifically, the effective half-caliber from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile of the first side surface of the first lens is T1a1; an effective half-caliber from the optical center of the first side surface of the first lens to the left edge of the effective diameter profile of the first side surface of the first lens is T1b1; an effective half-caliber from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens is T1c1; the effective half-caliber from the optical center of the first side surface of the first lens to the right edge of the effective diameter profile of the first side surface of the first lens is T1d1.
In an exemplary embodiment, the effective half-aperture of the second side of the first lens in the a2, b2, c2, d2 directions is as shown in fig. 14, specifically, the effective half-aperture from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens is T1a2; the effective half caliber from the optical center of the second side surface of the first lens to the left edge of the effective diameter outline of the second side surface of the first lens is T1b2; the effective half caliber from the optical center of the second side surface of the first lens to the lower edge of the effective diameter outline of the second side surface of the first lens is T1c2; the effective half-caliber from the optical center of the second side surface of the first lens to the right edge of the effective diameter profile of the second side surface of the first lens is T1d2.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 0.04< f/fz <0.16, where f is an effective focal length of the optical system and fz is a combined focal length of the first lens and the reflective polarizing element and the quarter-wave plate.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 1.5< (t1a1+t1c1)/f <2.2, where T1a1 is an effective half-caliber from an optical center of the first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens, T1c1 is an effective half-caliber from an optical center of the first side surface of the first lens to a lower edge of an effective diameter profile of the first side surface of the first lens, and f is an effective focal length of the optical system.
According to the optical system of the exemplary embodiment of the present application, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is a convex surface, the first side of the third lens is a concave surface, the second side is a convex surface, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The optical system has a positive and positive optical architecture, and simultaneously controls the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate to meet 0.04< f/fz <0.16, under the precondition, the control of the light emergent angle of the first lens can be facilitated by controlling the effective half caliber T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile, the effective half caliber T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile and the effective focal length f of the optical system to meet 1.5< (T1a1+T1c1)/f < 2.2.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 2.7< T1b1/CT1<4.7, where T1b1 is an effective half-caliber from an optical center of the first side surface of the first lens to a left edge of an effective diameter profile of the first side surface of the first lens, and CT1 is a center thickness of the first lens on the optical axis. The ratio of the effective half caliber of the optical center of the first side surface of the first lens to the left edge of the effective diameter outline of the first side surface of the first lens to the central thickness of the first lens on the optical axis is controlled within the range, so that the outer diameter size of the lens and the thickness ratio of the lens can be reasonably restrained, the forming of the lens is facilitated, and the thinning of the whole VR equipment is facilitated.
In an exemplary embodiment, the optical system of the present application may satisfy the condition 1.6< f 1/(t1a2+t1b2+t1c2+t1d2) <6.1, where f1 is an effective focal length of the first lens, T1a2 is an effective half-caliber from an optical center of the second side of the first lens to an upper edge of an effective diameter profile of the second side of the first lens, T1b2 is an effective half-caliber from an optical center of the second side of the first lens to a left edge of an effective diameter profile of the second side of the first lens, T1c2 is an effective half-caliber from an optical center of the second side of the first lens to a lower edge of an effective diameter profile of the second side of the first lens, and T1d2 is an effective half-caliber from an optical center of the second side of the first lens to a right edge of an effective diameter profile of the second side of the first lens. The effective semi-caliber of the edges in the upper, lower, left and right directions of the effective diameter profile can meet the condition 1.6< f 1/(T1a2+T1b2+T1c2+T1d2) <6.1 by controlling the effective focal length f1 of the first lens and the optical center of the second side surface of the first lens, so that the lens cannot be excessively bent; on the other hand, the outer diameter size of the lens can be ensured, both of which are advantageous in terms of moldability of the lens and lightness and thinness of the entire VR device.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 1.1< (CT 2+ CT 3)/(CT 1+ CTR + CTQ) <2.0, where CT2 is the center thickness of the second lens on the optical axis, CT3 is the center thickness of the third lens on the optical axis, CT1 is the center thickness of the first lens on the optical axis, CTR is the center thickness of the reflective polarizing element on the optical axis, and CTQ is the center thickness of the quarter wave plate on the optical axis. Through the central thickness of reasonable control first lens, second lens, third lens, reflective polarization component, quarter wave plate on the optical axis, can retrain the air interval between the lens, reduce the length of whole optical system, be favorable to the frivolousness of VR equipment.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 3.1< T1a1/EPD <4.3, where T1a1 is an effective half-caliber from an optical center of the first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens, and EPD is an entrance pupil diameter of the optical system. By controlling the ratio of the effective half caliber and the entrance pupil diameter from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile, the entrance pupil diameter can be increased on the premise of ensuring that the effective diameter size is certain, and the improvement of performance reduction caused by pupil deviation during eye rotation is facilitated, so that the comfort during eye vision is improved.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 2.0< (t1b1+t1d1)/TD <3.2, where T1b1 is an effective half-caliber from an optical center of the first side surface of the first lens to a left edge of an effective diameter profile of the first side surface of the first lens, T1d1 is an effective half-caliber from an optical center of the first side surface of the first lens to a right edge of an effective diameter profile of the first side surface of the first lens, and TD is a distance on an optical axis from the first side surface of the first lens to the second side surface of the third lens. The optical system is controlled to meet the condition of 2.0< (T1b1+T1d1)/TD <3.2, so that the overall length and the size of the visual system can be effectively restrained, and the later matching with a module is facilitated; meanwhile, the overall dimension of the whole optical lens is reduced as small as possible on the premise of ensuring the processability of the lens by restraining the overall dimension of the first lens.
In an exemplary embodiment, the optical system of the present application may satisfy the condition of 1.1< N1× (T1 a1/T1d 1) <1.4, where N1 is the refractive index of the first lens, T1a1 is the effective half-caliber from the optical center of the first side of the first lens to the upper edge of the effective diameter profile of the first side of the first lens, and T1d1 is the effective half-caliber from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens. By controlling the optical system to satisfy the conditional expression 1.1< n1× (T1 a1/T1d 1) <1.4, the external dimensions of the first lens can be ensured, and the refractive index of the first lens can be controlled so as to select a low refractive index, low stress material, thereby reducing the influence of stress on the polarization state of the entire optical system.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 1.5< (t1a2+t1c2)/(f×tan (Semi-FOV)) <2.0, where T1a2 is an effective half-caliber from an optical center of the second side surface of the first lens to an upper edge of an effective diameter profile of the second side surface of the first lens, T1c2 is an effective half-caliber from an optical center of the second side surface of the first lens to a lower edge of an effective diameter profile of the second side surface of the first lens, f is an effective focal length of the optical system, and Semi-FOV is a maximum half field angle of the optical system. The optical system is controlled to meet the condition that (T1a2+T1c2)/(f×tan (Semi-FOV)) <2.0, so that the view angle of the whole system can be effectively controlled, and the system can meet the characteristic of large view field of the VR lens; meanwhile, the optical performance of the system and the outer diameter size of the whole device can be reasonably distributed, and the experience of use is improved.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression-4.8 < f 3/(r5+r6) < -0.1, where f3 is an effective focal length of the third lens, R5 is a radius of curvature of the first side of the third lens, and R6 is a radius of curvature of the second side of the third lens. The curvature radius of the first side surface and the second side surface of the third lens and the effective focal length of the third lens are controlled to meet the condition-4.8 f 3/(R5+R6) < -0.1, so that the control of the third lens on the light emergent angle is facilitated, the back focus of the system is synchronously controlled, the total length of the system is controlled, and the miniaturization target of VR equipment is met.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression-1.1 < R4/f2< -0.1, where R4 is a radius of curvature of the second side surface of the second lens and f2 is an effective focal length of the second lens. By controlling the ratio of the radius of curvature of the second side of the second lens to the effective focal length of the second lens within the range, the shape of the second lens is constrained, which is beneficial to reducing the sensitivity of the second lens, thereby improving the yield of assembly.
In an exemplary embodiment, the optical system of the present application may satisfy the conditional expression 18.2mm < (NR/NQ) ×t1b2<23.3mm, where NR is the refractive index of the reflective polarizing element, NQ is the refractive index of the quarter-wave plate, and T1b2 is the effective half-caliber from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens. The refractive indexes of the reflective polarizing element and the quarter-wave plate are close by controlling the optical system to meet the condition of 18.2mm < (NR/NQ) x T1b2<23.3mm, so that the influence on the optical system when the thickness of the reflective polarizing element and the quarter-wave plate is changed is reduced, and the selectivity of the polarizing element is increased.
In an exemplary embodiment, the optical system of the present application may include at least one aperture. The diaphragm can restrict the light path and control the intensity of light. The aperture may be arranged in a suitable position of the optical system, for example the aperture may be located between the first side (e.g. the human eye side) and the first lens.
In an exemplary embodiment, the above optical system may optionally further include a protective glass for protecting the photosensitive element located on the imaging surface.
According to the optical system of the exemplary embodiment of the present application, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is a convex surface, the first side of the third lens is a concave surface, the second side is a convex surface, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The optical system has a positive and positive optical architecture, and simultaneously controls the effective focal length f of the optical system and the combined focal length fz of the first lens, the reflective polarizing element and the quarter-wave plate to meet 0.04< f/fz <0.16, under the precondition, the control of the light emergent angle of the first lens can be facilitated by controlling the effective half caliber T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter profile, the effective half caliber T1c1 from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile and the effective focal length f of the optical system to meet 1.5< (T1a1+T1c1)/f < 2.2.
On the other hand, according to the optical system of the present exemplary embodiment, the first lens having positive optical power, the second lens having positive optical power, and the third lens having positive optical power are sequentially included from the first side to the second side along the optical axis, wherein the second side of the second lens is convex, the first side of the third lens is concave, the second side is convex, and the first side or the second side of the first lens is attached with the reflective polarizing element and the quarter-wave plate. The optical system has a positive optical architecture, and meanwhile, the effective focal length f of the optical system, the first lens, the reflective polarizing element and the combined focal length fz of the quarter-wave plate are controlled to be 0.04< f/fz <0.16, under the precondition, the effective half-caliber T1a1 from the optical center of the first side surface of the first lens to the upper edge of the effective diameter outline of the first side surface of the first lens and the entrance pupil diameter EPD of the optical system are controlled to be 3.1< T1a1/EPD <4.3, so that the entrance pupil diameter is increased on the premise that the effective diameter is fixed, the performance degradation caused by pupil deviation during the rotation of human eyes is improved, and the comfort during the vision is improved.
Specific examples of the optical system applicable to the above-described embodiments are further described below with reference to the drawings.
Example 1
An optical system according to embodiment 1 of the present application is described below with reference to fig. 1 to 4. Fig. 1 shows a schematic configuration of an optical system according to embodiment 1 of the present application.
As shown in fig. 1, the optical system sequentially includes, from a first side to a second side along an optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, and a partially reflecting element BS.
In this embodiment, the first lens E1 has positive power, and the first side surface thereof is convex and the second side surface thereof is planar. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex.
In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass through the third lens E3, the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit toward the first side.
In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP may be attached to the second side of the first lens E1, specifically, the first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3.
Table 1 shows basic parameters of the optical system of example 1, in which the unit of radius of curvature and thickness are both millimeters (mm).
TABLE 1
In embodiment 1, the first side S2 of the first lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S8 and the second side S9 of the third lens E3 are all aspheric, and the surface shape x of the aspheric lens can be defined by, but not limited to, the following aspheric formula:
wherein x is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at the position with the height h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c=1/R (i.e., paraxial curvatureThe rate c is the inverse of the radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the aspherical i-th order. Table 2 below shows the higher order coefficients A that can be used for the aspherical mirror surfaces S2, S6-S9 in example 1 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 And A 20 。
| Coefficient/surface | S2 | S6 | S7 | S8 | S9 |
| A4 | 5.4237E-06 | -1.5885E-06 | 1.0446E-06 | -9.2231E-07 | 2.8132E-07 |
| A6 | -2.3989E-09 | -2.0729E-09 | 1.1980E-09 | -1.5926E-09 | -2.8440E-10 |
| A8 | 3.6552E-12 | -2.6708E-12 | 8.8833E-13 | -1.6433E-12 | -1.4642E-12 |
| A10 | 0.0000E+00 | -8.1094E-15 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A12 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A14 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A16 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A18 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A20 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
TABLE 2
Example 2
The structure of the optical system according to embodiment 2 of the present application is the same as that of the optical system described in embodiment 1, and includes, in order from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, and a partially reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the third lens E3, the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit toward the first side. The basic parameter table of the optical system of this example is the same as table 1, and the higher order coefficient table of the aspherical mirror surface is the same as table 2.
This embodiment differs from embodiment 1 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. Specifically, T1a1 is an effective half-caliber from an optical center of the first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens; t1b1 is the effective half caliber from the optical center of the first side surface of the first lens to the left edge of the effective diameter profile of the first side surface of the first lens; t1c1 is the effective half caliber from the optical center of the first side surface of the first lens to the lower edge of the effective diameter profile of the first side surface of the first lens; t1d1 is the effective half caliber from the optical center of the first side surface of the first lens to the right edge of the effective diameter profile of the first side surface of the first lens; t1a2 is the effective half caliber from the optical center of the second side surface of the first lens to the upper edge of the effective diameter contour of the second side surface of the first lens; t1b2 is the effective half caliber from the optical center of the second side surface of the first lens to the left edge of the effective diameter profile of the second side surface of the first lens; t1c2 is the effective half caliber from the optical center of the second side surface of the first lens to the lower edge of the effective diameter profile of the second side surface of the first lens; and T1d2 is the effective half-caliber from the optical center of the second side of the first lens to the right edge of the effective diameter profile of the second side of the first lens. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example and example 1 are shown in table 7 below, respectively.
Example 3
The structure of the optical system according to embodiment 3 of the present application is also the same as that of the optical system described in embodiment 1, and includes, in order from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a third lens E3, and a partially reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partial reflection element BS, the third lens E3, the second lens E2, and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the second lens E2, and the third lens E3 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the third lens E3, the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP, and the first lens E1 to exit toward the first side. The basic parameter table of the optical system of this example is also the same as table 1, and the higher order coefficient table of the aspherical mirror is also the same as table 2.
This embodiment is also different from embodiment 1 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example are also shown in Table 7 below.
Fig. 2 shows on-axis chromatic aberration curves of the optical systems of embodiment 1, embodiment 2, and embodiment 3, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 3 shows astigmatism curves of the optical systems of example 1, example 2, and example 3, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 4 shows distortion curves of the optical systems of example 1, example 2, and example 3, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 2 to 4, the optical systems given in embodiment 1, embodiment 2 and embodiment 3 can achieve good imaging quality.
Example 4
An optical system according to embodiment 4 of the present application is described below with reference to fig. 5 to 8. Fig. 5 shows a schematic structural diagram of an optical system according to embodiment 4 of the present application.
As shown in fig. 5, the optical system sequentially includes, from a first side to a second side along the optical axis: a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a partially reflecting element BS.
In this embodiment, the first lens E1 has positive power, and the first side surface thereof is a plane and the second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex.
In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 again to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP and the reflective polarizing element RP to exit toward the first side.
In this embodiment, the reflective polarizing element RP and the quarter wave plate QWP may be attached to the first side of the first lens E1, specifically, the second side of the quarter wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter wave plate QWP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3.
Table 3 shows basic parameters of the optical system of example 4, in which the unit of radius of curvature and thickness are both millimeters (mm). In this example, the second side S5 of the first optical lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S8 and the second side S9 of the third lens E3 are all aspherical, and Table 4 shows the higher order coefficients A that can be used for the aspherical mirror surfaces S5 to S9 in example 4 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 And A 20 Wherein each aspherical surface profile can be defined by the formula (1) given in the above-described embodiment 1.
| Surface of the body | Element | Surface type | Radius of curvature | Thickness of (L) | Refractive index | Abbe number | Refraction/reflection |
| S0 | Spherical surface | Infinity is provided | -1290.0000 | Refraction by refraction | |||
| S1 | Diaphragm (STO) | Spherical surface | Infinity is provided | 15.0000 | Refraction by refraction | ||
| S2 | Reflective polarizing element (RP) | Spherical surface | Infinity is provided | 0.1000 | 1.497 | 57.59 | Refraction by refraction |
| S3 | Quarter Wave Plate (QWP) | Spherical surface | Infinity is provided | 0.1000 | 1.497 | 57.59 | Refraction by refraction |
| S4 | First lens (E1) | Spherical surface | Infinity is provided | 5.0358 | 1.497 | 57.59 | Refraction by refraction |
| S5 | Aspherical surface | -107.3018 | 0.7610 | Refraction by refraction | |||
| S6 | Second lens (E2) | Aspherical surface | -165.6273 | 4.2617 | 1.546 | 55.99 | Refraction by refraction |
| S7 | Aspherical surface | -110.6135 | 0.9733 | Refraction by refraction | |||
| S8 | Third lens (E3) | Aspherical surface | -1467.9535 | 3.8395 | 1.546 | 55.99 | Refraction by refraction |
| S9 | Partial reflecting member (BS) | Aspherical surface | -90.7947 | -3.8395 | 1.546 | 55.99 | Reflection of |
| S10 | Aspherical surface | -1467.9535 | -0.9733 | Refraction by refraction | |||
| S11 | Aspherical surface | -110.6135 | -4.2617 | Refraction by refraction | |||
| S12 | Aspherical surface | -165.6273 | -0.7610 | Refraction by refraction | |||
| S13 | Aspherical surface | -107.3018 | -5.0358 | 1.497 | 57.59 | Refraction by refraction | |
| S14 | Quarter Wave Plate (QWP) | Spherical surface | Infinity is provided | -0.1000 | 1.497 | 57.59 | Refraction by refraction |
| S15 | Reflective polarizing element (RP) | Spherical surface | Infinity is provided | 0.1000 | 1.497 | 57.59 | Reflection of |
| S16 | First lens (E1) | Spherical surface | Infinity is provided | 5.0358 | 1.497 | 57.59 | Refraction by refraction |
| S17 | Aspherical surface | -107.3018 | 0.7610 | Refraction by refraction | |||
| S18 | Second lens (E2) | Aspherical surface | -165.6273 | 4.2617 | 1.546 | 55.99 | Refraction by refraction |
| S19 | Aspherical surface | -110.6135 | 0.9733 | Refraction by refraction | |||
| S20 | Third lens (E3) | Aspherical surface | -1467.9535 | 3.8395 | 1.546 | 55.99 | Refraction by refraction |
| S21 | Aspherical surface | -90.7947 | 0.9418 | Refraction by refraction | |||
| S22 | Image plane (IMG) | Spherical surface | Infinity is provided | 0.0000 | Refraction by refraction |
TABLE 3 Table 3
TABLE 4 Table 4
Example 5
The structure of the optical system according to embodiment 5 of the present application is the same as that of the optical system described in embodiment 4, and includes, in order from the first side to the second side along the optical axis: a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a partially reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is a plane and a second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The second side of the quarter wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter wave plate QWP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP and the reflective polarizing element RP to exit toward the first side. The basic parameter table of the optical system of this example is the same as table 3 in example 4, and the higher order coefficient table of the aspherical mirror surface is the same as table 4 in example 4.
This embodiment differs from embodiment 4 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example and example 4 are shown in table 7 below, respectively.
Example 6
The structure of the optical system according to embodiment 6 of the present application is also the same as that of the optical system described in embodiment 4, and includes, in order from the first side to the second side along the optical axis: a reflective polarizing element RP, a quarter wave plate QWP, a first lens E1, a second lens E2, a third lens E3 and a partially reflecting element BS. The first lens E1 has positive optical power, and a first side surface thereof is a plane and a second side surface thereof is a convex surface. The second lens E2 has positive focal power, the first side surface is concave, and the second side surface is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The second side of the quarter wave plate QWP is attached to the first side of the first lens E1, and the second side of the reflective polarizing element RP is attached to the first side of the quarter wave plate QWP. The partially reflective element BS may be a semi-transparent film layer plated on the second side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the partially reflective element BS, the third lens E3, the second lens E2, the first lens E1 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and again pass through the quarter wave plate QWP, the first lens E1, the second lens E2 and the third lens E3 to the partially reflective element BS, and then be reflected again at the partially reflective element BS and sequentially pass through the third lens E3, the second lens E2, the first lens E1, the quarter wave plate QWP and the reflective polarizing element RP to exit toward the first side. The basic parameter table of the optical system of this example is also the same as table 3 in example 4, and the higher order coefficient table of the aspherical mirror surface is also the same as table 4 in example 4.
This embodiment is also different from embodiment 4 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example are also shown in Table 7 below.
Fig. 6 shows on-axis chromatic aberration curves of the optical systems of examples 4, 5 and 6, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 7 shows astigmatism curves of the optical systems of example 4, example 5, and example 6, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 8 shows distortion curves of the optical systems of example 4, example 5, and example 6, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 6 to 8, the optical systems given in embodiment 4, embodiment 5 and embodiment 6 can achieve good imaging quality.
Example 7
An optical system according to embodiment 7 of the present application is described below with reference to fig. 9 to 12. Fig. 9 shows a schematic structural view of an optical system according to embodiment 7 of the present application.
As shown in fig. 9, the optical system sequentially includes, from a first side to a second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partially reflective element BS, and a third lens E3.
In this embodiment, the first lens E1 has positive power, and the first side surface thereof is convex and the second side surface thereof is planar. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex.
In this embodiment, the light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP and the first lens E1 to exit toward the first side.
In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP may be attached to the second side of the first lens E1, specifically, the first side of the reflective polarizing element RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizing element RP. The partially reflective element BS may be a semi-transparent film layer plated on the first side of the third lens E3.
Table 5 shows basic parameters of the optical system of example 7, in which the unit of radius of curvature and thickness are both millimeters (mm). In this example, the first side S2 of the first lens E1, the first side S6 and the second side S7 of the second lens E2, and the first side S16 and the second side S17 of the third lens E3 are all aspherical, and Table 6 shows the higher order coefficients A that can be used for the aspherical mirrors S2, S6-S7, and S16-S17 in example 7 4 、A 6 、A 8 、A 10 、A 12 、A 14 、A 16 、A 18 And A 20 Wherein each aspherical surface profile can be defined by the formula (1) given in the above-described embodiment 1.
TABLE 5
| Coefficient/surface | S2 | S6 | S7 | S16 | S17 |
| A4 | 7.2366E-06 | 6.0313E-07 | 9.2076E-06 | -7.1202E-07 | 3.0692E-06 |
| A6 | -5.2882E-09 | -3.5877E-09 | -2.5261E-09 | 3.0802E-09 | -2.0769E-08 |
| A8 | -7.8065E-12 | -9.0413E-12 | 1.0453E-11 | -4.9956E-12 | -4.2219E-11 |
| A10 | 0.0000E+00 | 0.0000E+00 | -1.4568E-14 | 0.0000E+00 | 1.2862E-13 |
| A12 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A14 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A16 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A18 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
| A20 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 | 0.0000E+00 |
TABLE 6
Example 8
The structure of the optical system according to embodiment 8 of the present application is the same as that of the optical system described in embodiment 7, and includes, in order from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partially reflective element BS, and a third lens E3. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the first side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP and the first lens E1 to exit toward the first side. The basic parameter table of the optical system of this example is the same as table 5 in example 7, and the higher order coefficient table of the aspherical mirror surface is the same as table 6 in example 7.
This embodiment differs from embodiment 7 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example and example 7 are shown in table 7 below, respectively.
Example 9
The structure of the optical system according to embodiment 9 of the present application is also the same as that of the optical system described in embodiment 7, and includes, in order from the first side to the second side along the optical axis: a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partially reflective element BS, and a third lens E3. The first lens E1 has positive optical power, and a first side surface thereof is convex and a second side surface thereof is plane. The second lens E2 has positive optical power, and the first side surface thereof is convex, and the second side surface thereof is convex. The third lens E3 has positive optical power, and the first side surface thereof is concave and the second side surface thereof is convex. The first side of the reflective polarizer RP is attached to the second side of the first lens E1, and the first side of the quarter-wave plate QWP is attached to the second side of the reflective polarizer RP. The partially reflective element BS may be a semi-transparent film layer plated on the first side of the third lens E3. The light beam emitted from the image plane IMG located at the second side may sequentially pass through the third lens E3, the partial reflection element BS, the second lens E2 and the quarter wave plate QWP to the reflective polarizing element RP, be reflected at the reflective polarizing element RP and pass through the quarter wave plate QWP and the second lens E2 again to the partial reflection element BS, and then be reflected again at the partial reflection element BS and sequentially pass through the second lens E2, the quarter wave plate QWP, the reflective polarizing element RP and the first lens E1 to exit toward the first side. The basic parameter table of the optical system of this example is also the same as table 5 in example 7, and the higher order coefficient table of the aspherical mirror surface is also the same as table 6 in example 7.
This embodiment is also different from embodiment 7 in that the values of the effective half apertures T1a1, T1b1, T1c1, T1d1 of the first side face of the first lens E1 in the a1, b1, c1, d1 directions are different, and the values of the effective half apertures T1a2, T1b2, T1c2, T1d2 of the second side face of the first lens in the a2, b2, c2, d2 directions are different. The values of T1a1, T1b1, T1c1, T1d1, T1a2, T1b2, T1c2, T1d2 in this example are also shown in Table 7 below.
Fig. 10 shows on-axis chromatic aberration curves of the optical systems of examples 7, 8, and 9, which represent the focus deviation of light rays of different wavelengths after passing through the lens. Fig. 11 shows astigmatism curves of the optical systems of examples 7, 8, and 9, which represent meridional image plane curvature and sagittal image plane curvature. Fig. 12 shows distortion curves of the optical systems of example 7, example 8, and example 9, which represent distortion magnitude values corresponding to different angles of view. As can be seen from fig. 10 to 12, the optical systems given in embodiment 7, embodiment 8 and embodiment 9 can achieve good imaging quality.
In the embodiments 1 to 9 of the present invention, the combined focal length fz of the first lens and the reflective polarizing element and the quarter-wave plate, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, the effective focal length f3 of the third lens, the effective focal length f of the optical system, the entrance pupil diameter EPD of the optical system, the optical axis distance TD of the first side of the first lens to the second side of the third lens, the optical axis center thickness CTR of the reflective polarizing element, the optical axis center thickness CTQ of the quarter-wave plate, the maximum half field angle Semi-FOV of the optical system, the optical center of the first side of the first lens to the effective radius profile upper edge of the first side of the first lens, the effective half aperture T1a 1' an effective half-diameter T1b1 from an optical center of a first side of the first lens to a left edge of an effective diameter profile of the first side of the first lens, an effective half-diameter T1c1 from an optical center of the first side of the first lens to a lower edge of an effective diameter profile of the first side of the first lens, an effective half-diameter T1d1 from an optical center of the first side of the first lens to a right edge of an effective diameter profile of the first side of the first lens, an effective half-diameter T1a2 from an optical center of a second side of the first lens to an upper edge of an effective diameter profile of the second side of the first lens, an effective half-diameter T1b2 from an optical center of the second side of the first lens to a left edge of an effective diameter profile of the second side of the first lens, the effective half-calibre T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens and the effective half-calibre T1d2 from the optical center of the second side of the first lens to the right edge of the effective diameter profile of the second side of the first lens are shown in table 7.
TABLE 7
Examples 1 to 9 each satisfy the conditions shown in table 8.
| Condition/example | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| f/fz | 0.15 | 0.15 | 0.15 | 0.11 | 0.11 | 0.11 | 0.05 | 0.05 | 0.05 |
| (T1a1+T1c1)/f | 1.82 | 1.68 | 1.94 | 1.75 | 1.89 | 2.02 | 2.04 | 1.91 | 1.76 |
| T1b1/CT1 | 3.08 | 2.80 | 3.02 | 4.19 | 4.62 | 4.53 | 3.68 | 3.75 | 3.40 |
| f1/(T1a2+T1b2+T1c2+T1d2) | 1.72 | 1.88 | 1.68 | 2.62 | 2.40 | 2.35 | 5.40 | 5.51 | 6.02 |
| (CT2+CT3)/(CT1+CTR+CTQ) | 1.20 | 1.20 | 1.20 | 1.55 | 1.55 | 1.55 | 1.98 | 1.98 | 1.98 |
| T1a1/EPD | 3.73 | 3.13 | 4.05 | 3.26 | 3.89 | 4.22 | 4.22 | 3.89 | 3.26 |
| (T1b1+T1d1)/TD | 2.41 | 2.19 | 2.36 | 2.84 | 3.13 | 3.07 | 2.21 | 2.25 | 2.05 |
| N1×(T1a1/T1d1) | 1.25 | 1.16 | 1.39 | 1.16 | 1.25 | 1.39 | 1.39 | 1.25 | 1.16 |
| (T1a2+T1c2)/(f×tan(Semi-FOV)) | 1.68 | 1.55 | 1.79 | 1.57 | 1.70 | 1.82 | 1.96 | 1.84 | 1.70 |
| f3/(R5+R6) | -0.80 | -0.80 | -0.80 | -0.11 | -0.11 | -0.11 | -4.75 | -4.75 | -4.75 |
| R4/f2 | -1.05 | -1.05 | -1.05 | -0.19 | -0.19 | -0.19 | -0.65 | -0.65 | -0.65 |
| (NRP/NQWP)×T1b2(mm) | 20.65 | 18.73 | 20.22 | 21.12 | 23.28 | 22.80 | 19.76 | 20.17 | 18.30 |
TABLE 8
The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It should be understood by those skilled in the art that the scope of protection referred to in this application is not limited to the specific combination of the above technical features, but also encompasses other technical solutions formed by any combination of the above technical features or their equivalents without departing from the spirit of the application. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.
Claims (10)
1. An optical system, comprising, in order from a first side to a second side along an optical axis:
a first lens having positive optical power;
a second lens having positive optical power, the second side of which is convex; and
a third lens with positive focal power, the first side surface of which is concave, and the second side surface of which is convex;
the optical system further includes: a reflective polarizing element and a quarter wave plate attached to the first side or the second side of the first lens;
The optical system satisfies:
0.04< f/fz <0.16, and
1.5<(T1a1+T1c1)/f<2.2，
wherein f is an effective focal length of the optical system, fz is a combined focal length of the first lens, the reflective polarizing element and the quarter-wave plate, T1a1 is an effective half-caliber from an optical center of the first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens, and T1c1 is an effective half-caliber from an optical center of the first side surface of the first lens to a lower edge of the effective diameter profile of the first side surface of the first lens.
2. The optical system of claim 1, wherein an effective half-diameter T1b1 from an optical center of the first side of the first lens to a left edge of an effective diameter profile of the first side of the first lens and a center thickness CT1 of the first lens on the optical axis satisfy:
2.7<T1b1/CT1<4.7。
3. the optical system of claim 1, wherein the effective focal length f1 of the first lens, the optical center of the second side of the first lens, and the effective half-caliber T1a2 from the optical center of the second side of the first lens to the upper edge of the effective diameter profile of the second side of the first lens, the effective half-caliber T1b2 from the optical center of the second side of the first lens to the left edge of the effective diameter profile of the second side of the first lens, the effective half-caliber T1c2 from the optical center of the second side of the first lens to the lower edge of the effective diameter profile of the second side of the first lens, and the effective half-caliber T1d2 from the optical center of the second side of the first lens to the right edge of the effective diameter profile of the second side of the first lens satisfy:
1.6<f1/(T1a2+T1b2+T1c2+T1d2)<6.1。
4. 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, a center thickness CT1 of the first lens on the optical axis, a center thickness CTR of the reflective polarizing element on the optical axis, and a center thickness CTQ of the quarter-wave plate on the optical axis satisfy:
1.1<(CT2+CT3)/(CT1+CTR+CTQ)<2.0。
5. the optical system of claim 1, wherein an entrance pupil diameter EPD of the optical system satisfies:
3.1<T1a1/EPD<4.3。
6. the optical system of claim 1, wherein a distance TD on the optical axis between an optical center of the first side of the first lens to an effective half-diameter T1b1 of the left edge of the effective diameter profile of the first side of the first lens, an effective half-diameter T1d1 of the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens, and a distance TD between the first side of the first lens to the second side of the third lens satisfies:
2.0<(T1b1+T1d1)/TD<3.2。
7. the optical system of claim 1, wherein the refractive index N1 of the first lens and the effective half-caliber T1d1 from the optical center of the first side of the first lens to the right edge of the effective diameter profile of the first side of the first lens satisfy:
1.1<N1×(T1a1/T1d1)<1.4。
8. The optical system of claim 1, wherein an effective half-diameter T1a2 from an optical center of the second side of the first lens to an upper edge of an effective diameter profile of the second side of the first lens, an effective half-diameter T1c2 from an optical center of the second side of the first lens to a lower edge of an effective diameter profile of the second side of the first lens, and a maximum half field angle Semi-FOV of the optical system satisfy:
1.5<(T1a2+T1c2)/(f×tan(Semi-FOV))<2.0。
9. an optical system, comprising, in order from a first side to a second side along an optical axis:
a first lens having positive optical power;
a second lens having positive optical power, the second side of which is convex; and
a third lens with positive focal power, the first side surface of which is concave, and the second side surface of which is convex;
the optical system further includes: a reflective polarizing element and a quarter wave plate attached to the first side or the second side of the first lens;
the optical system satisfies:
0.04< f/fz <0.16, and
3.1<T1a1/EPD<4.3，
wherein f is an effective focal length of the optical system, fz is a combined focal length of the first lens, the reflective polarizing element and the quarter-wave plate, T1a1 is an effective half-caliber from an optical center of the first side surface of the first lens to an upper edge of an effective diameter profile of the first side surface of the first lens, and EPD is an entrance pupil diameter of the optical system.
10. A VR device comprising the optical system of any one of claims 1-9, wherein the first side is a human eye side and the second side is a display side.
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