Visual system

Abstract

The utility model discloses a visual system which comprises a lens cone, an optical element group and a spacing element group, wherein the optical element group and the spacing element group are arranged in the lens cone; the optical element group comprises a first lens with positive focal power, a reflective polarization element, a first quarter-wave plate, a second lens with positive focal power, a third lens with negative focal power, a partial reflection element and a fourth lens with focal power which are sequentially arranged from the first side to the second side along the optical axis; a second quarter-wave plate and a linear polarization element; the spacing element group comprises a second spacing element; the second spacing element is arranged on the second side surface of the second lens and is in contact with the second side surface of the second lens; the effective focal length f2 of the second lens and the effective focal length f3 of the third lens meet the following conditions:-1.7 lt; f2 / f3lt; -1.2,-1.2; the curvature radius R4 of the second side surface of the second lens and the inner diameter d2s of the first side surface of the second spacing element meet the following conditions:-3.6 lt; r < 4 > / d < 2 < slt >; -1.5,-1.5; the curvature radius R5 of the first side surface of the third lens and the inner diameter d2m of the second side surface of the second spacing element satisfy the following formula:-2.2 lt; r < 5 > / d < 2 > mlt; and-1.6.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and in particular to a catadioptric optical system. Background Art

[0002] With the introduction of the concept of the metaverse, virtual reality and augmented reality technologies for human-computer interaction have ushered in a second opportunity for development. As an important entrance to human-computer interaction, the visual system plays a key role in it. The visual system is mainly divided into three types: optical systems using aspherical lenses, optical systems using Fresnel lenses, and catadioptric optical systems. Among them, the catadioptric optical system is a major innovation of the visual system itself, and it reserves space for the overall design of virtual reality equipment or augmented reality equipment, and has become the mainstream trend of research and development.

[0003] The catadioptric optical system shortens the length of the visual system by bending the optical path, thereby moving the center of gravity of the virtual reality device or augmented reality device backward and improving the user experience. However, the existing catadioptric optical system usually uses two lenses, which will cause the picture of the catadioptric optical system to be blurred and the image quality to be poor. Utility Model Content

[0004] The present application provides a visual system that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0005] One aspect of the present application provides such a visual system, which includes a lens barrel and an optical element group and a spacer element group disposed in the lens barrel. The optical element group includes a first lens with positive optical power, a reflective polarizing element, a first quarter-wave plate, a second lens with positive optical power, a third lens with negative optical power, a partial reflecting element, a fourth lens with optical power, a second quarter-wave plate, and a linear polarizing element arranged in sequence from the first side to the second side along the optical axis; the spacer element group includes a second spacer element, which is disposed on the second side of the second lens and contacts the second side of the second lens; wherein the effective focal length f2 of the second lens and the effective focal length f3 of the third lens satisfy: -1.7 <f2 / f3<-1.2;第二透镜的第二侧面的曲率半径R4与第二间隔元件的第一侧面的内径d2s满足:-3.6<R4 / d2s<-1.5;第三透镜的第一侧面的曲率半径R5与第二间隔元件的第二侧面的内径d2m满足:-2.2<R5 / d2m<-1.6。

[0006] According to an exemplary embodiment of the present application, the total effective focal length f of the visual system and the length L of the lens barrel along the direction of the optical axis satisfy: 1.8 <f / L<2.0。

[0007] According to an exemplary embodiment of the present application, the on-axis distance T23 from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness CP2 of the second spacer element satisfy: 0.1 < T23 / CP2 < 1.1.

[0008] According to an exemplary embodiment of the present application, the inner diameter d0s of the first side end surface of the lens barrel and the inner diameter d0m of the second side end surface of the lens barrel satisfy: 1.9 < d0s / d0m ≤ 2.1.

[0009] According to an exemplary embodiment of the present application, the outer diameter D0s of the first side end surface of the lens barrel and the radius of curvature R1 of the first side surface of the first lens satisfy: 1.5 < D0s / R1 < 1.9.

[0010] According to an exemplary embodiment of the present application, the outer diameter D2s of the first side surface of the second spacer element, the outer diameter D2m of the second side surface of the second spacer element and the outer diameter D0m of the second side end surface of the lens barrel satisfy: 1.8 < (D2s + D2m) / D0m < 2.9.

[0011] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element, and the first spacer element is placed on the second side surface of the first lens and in contact with the second side surface of the first lens. Wherein, the on-axis spacing distance EP01 between the first side end surface of the lens barrel and the first spacer element, the maximum thickness CP1 of the first spacer element and the on-axis central thickness CT1 of the first lens satisfy: 0.5 < (EP01 + CP1) / CT1 ≤ 0.8.

[0012] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element, and the first spacer element is placed on the second side surface of the first lens and in contact with the second side surface of the first lens. Wherein, the on-axis central thickness CTR of the reflective polarizing element, the on-axis central thickness CTQ1 of the first quarter-wave plate, the on-axis central thickness CT2 of the second lens and the on-axis spacing distance EP12 between the first spacer element and the second spacer element satisfy: 2.2 < (CTR + CTQ1 + CT2) / EP12 < 2.4.

[0013] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element, and the first spacer element is placed on the second side surface of the first lens and in contact with the second side surface of the first lens. Wherein, the combined focal length fz1 of the first lens, the reflective polarizing element, the first quarter-wave plate and the second lens, the outer diameter D1s of the first side surface of the first spacer element and the outer diameter D1m of the second side surface of the first spacer element satisfy: 0.4 < fz1 / (D1s + D1m) < 1.2.

[0014] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element, and the first spacer element is disposed on the second side surface of the first lens and in contact with the second side surface of the first lens. Wherein, the effective focal length f1 of the first lens and the inner diameter d1s of the first side surface of the first spacer element satisfy: 0.2 < d1s / f1 < 0.9.

[0015] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element, and the third spacer element is disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. Wherein, the effective focal length f3 of the third lens, the inner diameter d3s of the first side surface of the third spacer element, and the outer diameter D3s of the first side surface of the third spacer element satisfy: -2.8 < f3 / (d3s + D3s) < -1.4.

[0016] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element, and the third spacer element is disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. The spacing distance EP23 between the second spacer element and the third spacer element along the optical axis, the maximum thickness CP3 of the third spacer element, and the central thickness CT3 of the third lens on the optical axis satisfy: 1.2 < (EP23 + CP3) / CT3 ≤ 2.1.

[0017] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element, and the third spacer element is disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. Wherein, the combined focal length fz2 of the third lens, the fourth lens, the second quarter-wave plate, and the linear polarization element and the inner diameter d3m of the second side surface of the third spacer element satisfy: 1.0 < |fz2| / d3m < 2.2.

[0018] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element, and the third spacer element is disposed on the second side surface of the third lens and in contact with the second side surface of the third lens. Wherein, the effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacer element satisfy: 1.0 < |f4| / D3m < 1.4.

[0019] According to an exemplary embodiment of the present application, the first quarter-wave plate is disposed on the first side surface of the second lens; the reflective polarizing element is disposed on the first side surface of the first quarter-wave plate; the partial reflection element is disposed on the second side surface of the third lens; the second quarter-wave plate is disposed on the second side surface of the fourth lens; and the linear polarization element is disposed on the second side surface of the second quarter-wave plate.

[0020] The visual system provided by this application uses four lenses. By reasonably configuring the optical powers of the four lenses and making the visual system satisfy "-1.7 < f2 / f3 < -1.2", it is beneficial to improve the imaging quality of the visual system. At the same time, by cooperating with restricting the ratio of the curvature radius of the second side of the second lens to the inner diameter of the first side of the second spacer element and the ratio of the curvature radius of the first side of the third lens to the inner diameter of the second side of the second spacer element, the inner diameters of the first side and the second side of the second spacer element can be constrained within an appropriate range. While ensuring that the second spacer element has good processability, the second spacer element effectively blocks excess light, reducing the stray light risk and ghost image risk of the visual system. Description of the Drawings

[0021] Other features, objects, and advantages of this application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings. Among them:

[0022] Figure 1 Shows a schematic diagram of parameter markings of the visual system according to this application;

[0023] Figure 2 Shows a schematic structural diagram of the visual system according to Embodiment 1 of this application;

[0024] Figure 3 Shows a schematic structural diagram of the visual system according to Embodiment 2 of this application;

[0025] Figure 4 Shows a schematic structural diagram of the visual system according to Embodiment 3 of this application;

[0026] Figure 5A 、 Figure 5B 、 Figure 5C 、 Figure 5D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function (MTF) curve of the visual system according to Embodiment 1, 2, or 3 of this application;

[0027] Figure 6 Shows a schematic structural diagram of the visual system according to Embodiment 4 of this application;

[0028] Figure 7 Shows a schematic structural diagram of the visual system according to Embodiment 5 of this application;

[0029] Figure 8 Shows a schematic structural diagram of the visual system according to Embodiment 6 of this application;

[0030] Figure 9A 、 Figure 9B 、 Figure 9C 、Figure 9D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the visual system according to Embodiment 4, 5, or 6 of the present application;

[0031] Figure 10 shows a schematic structural diagram of the visual system according to Embodiment 7 of the present application;

[0032] Figure 11 shows a schematic structural diagram of the visual system according to Embodiment 8 of the present application;

[0033] Figure 12 shows a schematic structural diagram of the visual system according to Embodiment 9 of the present application; and

[0034] Figure 13A 、 Figure 13B 、 Figure 13C 、 Figure 13D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the visual system according to Embodiment 7, 8, or 9 of the present application. Detailed Embodiments

[0035] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements.

[0036] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0037] In the drawings, for the sake of convenience of illustration, the thickness, size, and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0038] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface 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 called the first side surface of the lens, and the surface of each lens closest to the second side (e.g., the display screen side) is called the second side surface of the lens.

[0039] It should also be understood that the terms "comprising", "comprises", "having", "includes" and / or "including", when used in this specification, denote the presence of the stated features, elements and / or components, but do not preclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when describing the embodiments of the present application, the 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.

[0040] 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 should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning 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.

[0041] It should be noted that, without conflict, the embodiments and features in the embodiments of this application may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0042] The features, principles and other aspects of the present application will be described in detail below.

[0043] Reference Figures 2 to 4 、 Figures 6 to 8 and Figures 10 to 12 , a first aspect of the present application provides a visual system that may include an optical element group, and the optical element group may include a first lens, a reflective polarizing element, a first quarter-wave plate, a second lens, a third lens, a partial reflection element, a fourth lens, a second quarter-wave plate, and a linear polarizing element arranged in sequence along the optical axis from the first side to the second side.

[0044] In an exemplary embodiment, the first lens may have a positive optical power. The second lens may have a positive optical power. The third lens may have a negative optical power. The fourth lens may have a positive optical power or a negative optical power. Reasonably configuring the optical powers of each lens is beneficial to improving the imaging quality of the visual system.

[0045] In an exemplary embodiment, the first side of the first lens may be convex, and the second side may be concave.

[0046] In an exemplary embodiment, the first side of the second lens may be flat, and the second side may be convex.

[0047] In an exemplary embodiment, the first side of the third lens may be concave, and the second side may be convex or concave.

[0048] In an exemplary embodiment, the first side surface of the fourth lens may be convex or concave, and the second side surface may be planar.

[0049] In an exemplary embodiment, the first quarter-wave plate may be disposed on the first side surface of the second lens. The first quarter-wave plate is used to change the polarization state of light. For example, it can convert circularly polarized light into linearly polarized light, or convert linearly polarized light into circularly polarized light. The circularly polarized light may include right-handed circularly polarized light or left-handed circularly polarized light. The linearly polarized light may include S linearly polarized light or P linearly polarized light.

[0050] In an exemplary embodiment, the reflective polarizing element may be disposed on the first side surface of the first quarter-wave plate. The reflective polarizing element is used to reflect linearly polarized light in a predetermined direction and transmit linearly polarized light orthogonal to the predetermined direction. For example, the reflective polarizing element may reflect S linearly polarized light and transmit P linearly polarized light, or the reflective polarizing element may reflect P linearly polarized light and transmit S linearly polarized light.

[0051] In an exemplary embodiment, the first side surface of the second lens may be planar. The reflective polarizing element and the first quarter-wave plate are bonded and attached to the first side surface of the second lens. By combining the reflective polarizing element and the first quarter-wave plate together and then attaching them to the first side plane of the second lens, the difficulty of the attachment process can be reduced, the attachment quality can be improved, and thus the performance of the visual system can be enhanced.

[0052] In an exemplary embodiment, the partial reflection element may be disposed on the second side surface of the third lens. The partial reflection element has a semi-transmissive and semi-reflective effect on light. By disposing the partial reflection element on the second side surface of the third lens and combining it with the reflective polarizing element and the first quarter-wave plate, the light can be refracted multiple times, effectively reducing the body length of the visual system.

[0053] In an exemplary embodiment, the second quarter-wave plate may be disposed on the second side surface of the fourth lens. The linear polarizing element may be disposed on the second side surface of the second quarter-wave plate. The linear polarizing element is used to convert natural light emitted from the display screen on the second side into linearly polarized light, and the second quarter-wave plate is used to convert the linearly polarized light from the linear polarizing element into circularly polarized light (e.g., right-handed circularly polarized light or left-handed circularly polarized light). By using the second quarter-wave plate and the linear polarizing element, the natural light emitted from the display screen can be converted into circularly polarized light, thereby reducing the influence of the material stress of the components between the display screen and the linear polarizing element and improving the contrast of the visual system.

[0054] In an exemplary embodiment, the second side surface of the fourth lens may be a plane. The second quarter-wave plate and the linear polarization element are bonded and attached to the second side surface of the fourth lens. By combining the second quarter-wave plate and the linear polarization element together and then attaching them to the second side plane of the fourth lens, the difficulty of the attachment process can be reduced, the attachment quality can be improved, and thus the performance of the visual system can be improved.

[0055] In an exemplary embodiment, the visual system may further include a diaphragm, and the diaphragm may be disposed between the first side and the first lens. The image light from the second side passes through the linear polarization element, the second quarter-wave plate, the fourth lens, the third lens, the second lens, the first quarter-wave plate, the reflective polarizing element, the first lens, etc. after multiple refractions and reflections, and finally projects onto the eyes of the user on the first side.

[0056] In an exemplary embodiment, the first side may be the human eye side, and the second side may be the display screen side. Correspondingly, the first side surfaces of the respective elements (the first lens, the reflective polarizing element, the first quarter-wave plate, the second lens, the third lens, the fourth lens, the first quarter-wave plate) may be referred to as the near-human-eye side surfaces, and the second side surfaces may be referred to as the near-screen side surfaces.

[0057] In an exemplary embodiment, an image plane may be provided on the second side of the visual system. A display screen may be provided on the image plane. The image light from the display screen can sequentially pass through the linear polarization element, the second quarter-wave plate, the fourth lens, the third lens, the second lens, the first quarter-wave plate, reach the reflective polarizing element, and then be reflected at the reflective polarizing element to form the first reflected image light. The first reflected image light passes through the first quarter-wave plate, the second lens, the third lens and reaches the partial reflection element on the second side surface of the third lens, and then is reflected at the partial reflection element to form the second reflected image light. The second reflected image light sequentially passes through the third lens, the second lens, the first quarter-wave plate, the reflective polarizing element, the first lens to the diaphragm and finally projects into the eyes of the user. The visual system provided in the present application folds the required optical path by a combination of light reflection and refraction without affecting the projection quality, effectively shortening the body length of the visual system.

[0058] In an exemplary embodiment, the visual system may further include a set of spacer elements. The set of spacer elements may include one or more of a first spacer element, a second spacer element, and a third spacer element. The first spacer element may be disposed on the second side surface of the first lens and at least partially in contact with the second side surface of the first lens. The second spacer element may be disposed on the second side surface of the second lens and at least partially in contact with the second side surface of the second lens. The third spacer element may be disposed on the second side surface of the third lens and at least partially in contact with the second side surface of the third lens. Reasonable use of the spacer elements can effectively avoid the risk of stray light, reduce the interference with image quality, and thus improve the imaging quality of the visual system.

[0059] In an exemplary embodiment, the visual system may further include a barrel. The optical element group and the set of spacer elements may be disposed within the barrel. The barrel may include a first side end face, a second side end face, an outer ring face, and an inner ring face. Among them, the end face of the barrel closest to the first side is the first side end face of the barrel, and the end face of the barrel closest to the second side is the second side end face of the barrel; in the direction perpendicular to the optical axis, the surface of the barrel farthest from the optical axis is the outer ring face, and the surface of the barrel closest to the optical axis is the inner ring face.

[0060] In an exemplary embodiment, the effective focal length f2 of the second lens and the effective focal length f3 of the third lens may satisfy: -1.7 < f2 / f3 < -1.2. Reasonably configuring the ratio of the effective focal length of the second lens to the effective focal length of the third lens is beneficial to improving the imaging quality of the visual system.

[0061] In an exemplary embodiment, the radius of curvature R4 of the second side surface of the second lens and the inner diameter d2s of the first side surface of the second spacer element may satisfy: -3.6 < R4 / d2s < -1.5; the radius of curvature R5 of the first side surface of the third lens and the inner diameter d2m of the second side surface of the second spacer element may satisfy: -2.2 < R5 / d2m < -1.6. Reasonably configuring the ratio of the radius of curvature of the second side surface of the second lens to the inner diameter of the first side surface of the second spacer element and the ratio of the radius of curvature of the first side surface of the third lens to the inner diameter of the second side surface of the second spacer element can constrain the inner diameters of the first side surface and the second side surface of the second spacer element within an appropriate range. While ensuring that the second spacer element has good processability, the second spacer element can effectively block excess light, reducing the risk of stray light and ghost images in the visual system.

[0062] In an exemplary embodiment, the total effective focal length f of the visual system and the length L of the lens barrel in the direction of the optical axis may satisfy: 1.8 < f / L < 2.0. By reasonably configuring the ratio of the total effective focal length of the visual system to the length of the lens barrel in the direction of the optical axis, the length of the lens barrel in the direction of the optical axis can be constrained within a certain range. While ensuring good machinability of the lens barrel, it is beneficial for the visual system to be miniaturized and avoid the problem of excessive length of the visual system and its entire equipment caused by an overly long lens barrel.

[0063] In an exemplary embodiment, the on-axis distance T23 from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness CP2 of the second spacer element may satisfy: 0.1 < T23 / CP2 < 1.1. By reasonably configuring the ratio of the on-axis distance from the second side surface of the second lens to the first side surface of the third lens to the maximum thickness of the second spacer element, the maximum thickness of the second spacer element can be constrained within a certain range. While ensuring good machinability and relatively high structural strength of the second spacer element, it is beneficial for the visual system to be miniaturized and avoid the problems of excessive thickness of the visual system and its entire equipment and poor experience effect caused by an overly large thickness of the second spacer element.

[0064] In an exemplary embodiment, the inner diameter d0s of the first side end surface of the lens barrel and the inner diameter d0m of the second side end surface of the lens barrel may satisfy: 1.9 < d0s / d0m ≤ 2.1. By reasonably configuring the ratio of the inner diameter of the first side end surface of the lens barrel to the inner diameter of the second side end surface of the lens barrel, the outer shapes of the lenses and spacer elements inside the lens barrel can be restricted, enabling the lenses and spacer elements inside the lens barrel to have appropriate outer diameters, thereby reducing the processing difficulty of the lenses and spacer elements inside the lens barrel and improving their machinability; at the same time, it can also avoid problems such as excessive opening of the lens barrel, steep inner wall surface trend, and poor machinability of the lens barrel caused by an overly large ratio, and improve the machinability of the lens barrel.

[0065] In an exemplary embodiment, the outer diameter D0s of the first side end surface of the lens barrel and the radius of curvature R1 of the first side surface of the first lens may satisfy: 1.5 < D0s / R1 < 1.9. By reasonably configuring the ratio of the outer diameter of the first side end surface of the lens barrel to the radius of curvature of the first side surface of the first lens, the outer diameter of the first side end surface of the lens barrel can be constrained within a certain range, improving the machinability of the lens barrel.

[0066] In an exemplary embodiment, the outer diameter D2s of the first side surface of the second spacer element, the outer diameter D2m of the second side surface of the second spacer element, and the outer diameter D0m of the second side end surface of the lens barrel may satisfy: 1.8 < (D2s + D2m) / D0m < 2.9. By reasonably configuring the ratio of the sum of the outer diameters of the first side surface and the second side surface of the second spacer element to the outer diameter of the second side end surface of the lens barrel, the outer diameters of the first side surface and the second side surface of the second spacer element can be constrained within a certain range, so that the second spacer element has a sufficient bearing area, thereby ensuring that the second spacer element has good supporting ability; at the same time, the external dimensions of the visual system can also be restricted to ensure that the visual system and its whole machine equipment have smaller external dimensions.

[0067] In an exemplary embodiment, the axial spacing distance EP01 between the first side end surface of the lens barrel and the first spacer element, the maximum thickness CP1 of the first spacer element, and the central thickness CT1 of the first lens on the optical axis may satisfy: 0.5 < (EP01 + CP1) / CT1 ≤ 0.8. By controlling the above conditional expression, the thicknesses of the first spacer element and the first lens can be reasonably allocated, so that the first spacer element and the first lens have high structural strength and good supporting ability; at the same time, the body length of the visual system can also be restricted to avoid the problems of excessive thickness of the visual system and its whole machine equipment and poor experience effect caused by the excessive thicknesses of the first spacer element and the first lens.

[0068] In an exemplary embodiment, 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 CT2 of the second lens on the optical axis, and the axial spacing distance EP12 between the first spacer element and the second spacer element may satisfy: 2.2 < (CTR + CTQ1 + CT2) / EP12 < 2.4. By controlling the above conditional expression, the thicknesses of the reflective polarizing element and the first quarter-wave plate can be constrained within a reasonable range, ensuring that the reflective polarizing element and the first quarter-wave plate have good processability, and at the same time, the problem of excessive wrinkles generated when the reflective polarizing element and the first quarter-wave plate are attached due to excessive thickness can also be avoided, improving the optical performance of the visual system.

[0069] In an exemplary embodiment, the combined focal length fz1 of the first lens, the reflective polarizing element, the first quarter-wave plate, and the second lens, the outer diameter D1s of the first side surface of the first spacer element, and the outer diameter D1m of the second side surface of the first spacer element may satisfy: 0.4 < fz1 / (D1s + D1m) < 1.2. By controlling the above conditional expression, the outer diameters of the first side surface and the second side surface of the first spacer element can be constrained within a reasonable range, so that the first spacer element has a sufficient bearing area, thereby ensuring that the first spacer element has good supporting ability; at the same time, the external dimensions of the visual system can also be limited to ensure that the visual system and its entire machine equipment have smaller external dimensions.

[0070] In an exemplary embodiment, the effective focal length f1 of the first lens and the inner diameter d1s of the first side surface of the first spacer element may satisfy: 0.2 < d1s / f1 < 0.9. By reasonably configuring the ratio of the inner diameter of the first side surface of the first spacer element to the effective focal length of the first lens, the inner diameter of the first side surface of the first spacer element can be constrained within a certain range, improving the processability of the first spacer element; at the same time, the effective focal length of the first lens can also be made positive to ensure that the first lens converges light.

[0071] In an exemplary embodiment, the effective focal length f3 of the third lens, the inner diameter d3s of the first side surface of the third spacer element, and the outer diameter D3s of the first side surface of the third spacer element may satisfy: -2.8 < f3 / (d3s + D3s) < -1.4. By controlling the above conditional expression, the inner diameter and the outer diameter of the first side surface of the third spacer element can be constrained within a reasonable range. While ensuring that the third spacer element has good processability, the third spacer element has a sufficient bearing area, improving the supporting ability of the third spacer element.

[0072] In an exemplary embodiment, the spacing distance EP23 along the optical axis between the second spacer element and the third spacer element, the maximum thickness CP3 of the third spacer element, and the central thickness CT3 of the third lens on the optical axis may satisfy: 1.2 < (EP23 + CP3) / CT3 ≤ 2.1. By controlling the above conditional expression, the thicknesses of the third spacer element and the third lens can be reasonably allocated, so that the third spacer element and the third lens have high structural strength and good supporting ability; at the same time, the body length of the visual system can also be limited to avoid the problem that the thickness of the visual system and its entire machine equipment is too large and the user experience effect is poor due to the excessive thicknesses of the third spacer element and the third lens.

[0073] In an exemplary embodiment, the combined focal length fz2 of the third lens, the fourth lens, the second quarter-wave plate, and the linear polarization element and the inner diameter d3m of the second side surface of the third spacer element may satisfy: 1.0 < |fz2| / d3m < 2.2. By controlling the above conditional expression, the inner diameter of the second side surface of the third spacer element can be constrained within a reasonable range, ensuring good processability of the third spacer element.

[0074] In an exemplary embodiment, the effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacer element may satisfy: 1.0 < |f4| / D3m < 1.4. By reasonably configuring the ratio of the absolute value of the effective focal length of the fourth lens to the outer diameter of the second side surface of the third spacer element, the outer diameter of the second side surface of the third spacer element can be constrained within a certain range, such that the third spacer element has sufficient bearing area, ensuring good supporting ability of the third spacer element; at the same time, the processability of the third spacer element can also be improved.

[0075] The visual system according to the above embodiments of the present application may employ multiple lenses, such as the four lenses described above. By reasonably allocating the parameters of the reflective polarizing element, the first quarter-wave plate, each lens, the lens barrel, and each spacer element, the body length of the visual system can be reduced, and the processability, assembly stability, and imaging quality of the visual system can be improved. The visual system configured as above has characteristics such as miniaturization and good imaging quality, and can well meet the usage requirements of various portable electronic products in the projection scenario. Moreover, the center of gravity of the visual system and the electronic device including the visual system moves backward, improving the user's wearing experience.

[0076] In an embodiment of the present application, at least one of the surfaces of each of the first lens to the fourth lens is an aspherical surface. The characteristics of an aspherical lens are that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0077] However, those skilled in the art should understand that without departing from the technical solutions claimed in the present application, the number of lenses constituting the visual system can be changed to obtain the various results and advantages described in this specification.

[0078] The second aspect of the present application provides a visual system, which may include a barrel and an optical element group disposed within the barrel. The optical element group may include, in order from a first side to a second side along the optical axis, a first lens with a positive optical power, a reflective polarizing element, a first quarter-wave plate, a second lens with a positive optical power, a third lens with a negative optical power, a partially reflective element, a fourth lens with an optical power, a second quarter-wave plate, and a linear polarizing element.

[0079] The effective focal length f2 of the second lens and the effective focal length f3 of the third lens may satisfy: -1.7 < f2 / f3 < -1.2; the inner diameter d0s of the first-side end face of the barrel and the inner diameter d0m of the second-side end face of the barrel may satisfy: 1.9 < d0s / d0m ≤ 2.1. The visual system provided by the present application uses four lenses, rationally configures the optical powers of the four lenses, and makes the visual system satisfy "-1.7 < f2 / f3 < -1.2", which is beneficial to improving the imaging quality of the visual system; at the same time, by cooperating with restricting the ratio of the inner diameter of the first-side end face of the barrel to the inner diameter of the second-side end face of the barrel, the outer shapes of the lenses and spacer elements within the barrel can be restricted, so that the lenses and spacer elements within the barrel have appropriate outer diameters, thereby reducing the processing difficulty of the lenses and spacer elements within the barrel and improving the processability of the lenses and spacer elements within the barrel; it can also avoid problems such as excessive opening of the barrel, steep inner wall surface trend, and poor processability of the barrel caused by too large a ratio, and improve the processability of the barrel.

[0080] The following further describes specific embodiments of the visual system applicable to the above embodiments with reference to the accompanying drawings.

[0081] Example 1

[0082] The following refers to Figure 2 Describe the visual system according to Embodiment 1 of the present application.

[0083] As Figure 2 shown, the visual system may include a barrel P0 and an optical element group and a spacer element group disposed within the barrel P0.

[0084] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarizing element LP, which are arranged in sequence along the optical axis from the first side to the second side. A diaphragm STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. The first side surfaces of all the elements (e.g., the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the first spacer element P1, the second spacer element P2, and the third spacer element P3) are all referred to as the side surfaces close to the human eye, and the second side surfaces are all referred to as the side surfaces close to the screen.

[0085] The first lens E1 has a positive optical power. Its side surface S1 close to the human eye is convex, and its side surface S2 close to the screen is concave. The second lens E2 has a positive optical power. Its side surface S3 close to the human eye is flat, and its side surface S4 close to the screen is convex. The third lens E3 has a negative optical power. Its side surface S5 close to the human eye is concave, and its side surface S6 close to the screen is concave. The fourth lens E4 has a negative optical power. Its side surface S7 close to the human eye is concave, and its side surface S8 close to the screen is flat. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the side surface S3 close to the human eye of the second lens E2. The partial reflection element BS is attached to the side surface S6 close to the screen of the third lens E3. The second quarter-wave plate QWP2 and the linear polarizing element LP are attached to the side surface S8 close to the screen of the fourth lens E4.

[0086] In this example, an image plane IMG may be provided on the second side of the visual system. The image plane IMG may be provided with a display screen, for example. After the image light from the image plane IMG sequentially passes through the linear polarizing element LP, the second quarter-wave plate QWP2, the fourth lens E4, the third lens E3, the second lens E2, the first quarter-wave plate QWP1 and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. The light after the first reflection passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches the partial reflection element BS located on the side surface close to the screen of the third lens E3, and a second reflection occurs at the partial reflection element BS. The light after the second reflection sequentially passes through the third lens E3, the second lens E2, the first quarter-wave plate QWP1, the reflective polarizing element RP, the first lens E1 to the diaphragm and finally projects into the user's eyes. For example, the light of the visual system after two reflections finally projects into the user's eyes. A protective glass (not shown) may also be provided between the image plane IMG and the linear polarizing element LP.

[0087] Table 1 shows the basic parameter table of the visual system in Embodiment 1, where the units of the radius of curvature and the thickness / distance are both millimeters (mm). The image light from the image plane IMG passes through each element in the order of serial number 23 to serial number 1 and is finally projected into the human eye.

[0088]

[0089]

[0090] Table 1

[0091] In this embodiment, the side S5 close to the human eye and the side S6 close to the screen of the third lens E3, and the side S7 close to the human eye of the fourth lens E4 are all aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0092]

[0093] where x is the sagitta, the distance from the vertex of the aspherical surface at the position with a height of h along the optical axis direction; c is the paraxial curvature of the aspherical surface, c = 1 / R (that is, the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 , and A 20 that can be used for the aspherical surfaces S5 - S7 in Embodiment 1.

[0094] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S5 -1.7566E+00 -9.1856E-01 -6.6580E-01 -3.1489E-01 -1.1832E-01 -3.0614E-02 -4.3324E-03 0.0000E+00 0.0000E+00 S6 7.7626E-01 1.5793E-01 1.1307E-02 2.3290E-02 1.3885E-02 3.6322E-03 2.4337E-04 0.0000E+00 0.0000E+00 S7 1.0218E-01 -2.8597E-02 -3.6943E-03 -2.9453E-03 -9.3725E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0095] Table 2

[0096] Example 2

[0097] The following refers to Figure 3 to describe the visual system according to Embodiment 2 of the present application.

[0098] As Figure 3 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0099] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarizing element LP, which are arranged in sequence along the optical axis from the first side to the second side. A stop STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0100] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 1, that is, the basic parameter table of the visual system in this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some elements in the lens barrel P0 and the spacer element group are different.

[0101] Example 3

[0102] The following refers to Figure 4 Describe the visual system according to Embodiment 3 of the present application.

[0103] As Figure 4 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0104] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarizing element LP, which are arranged in sequence along the optical axis from the first side to the second side. A stop STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0105] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 1, that is, the basic parameter table of the visual system in this embodiment is the same as Table 1, and the aspheric coefficient table is the same as Table 2. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some elements in the lens barrel P0 and the spacer element group are different.

[0106] Figure 5A The axial chromatic aberration curve of the visual system of Embodiment 1, 2 or 3 is shown, which represents the deviation of the focusing points of light rays of different wavelengths after passing through the visual system. Figure 5B The astigmatism curve of the visual system of Embodiment 1, 2 or 3 is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 5CThe distortion curve of the visual system of Embodiment 1, 2 or 3 is shown, which represents the distortion magnitude values corresponding to different field angles of view. Figure 5D The modulation transfer function curve of the visual system of Embodiment 1, 2 or 3 is shown. According to Figures 5A to 5D it can be known that the visual systems given in Embodiment 1, 2 or 3 can achieve good imaging quality.

[0107] Example 4

[0108] The following refers to Figure 6 describe the visual system according to Embodiment 4 of the present application.

[0109] As Figure 6 shown, the visual system may include a barrel P0 and an optical element group and a spacer element group disposed within the barrel P0.

[0110] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarizing element LP arranged in sequence along the optical axis from the first side to the second side. A stop STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. The first side surfaces of each element (for example, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the first spacer element P1, the second spacer element P2, and the third spacer element P3) are all referred to as the near-eye side surfaces, and the second side surfaces are all referred to as the near-screen side surfaces.

[0111] The first lens E1 has a positive optical power, its near-eye side surface S1 is convex, and its near-screen side surface S2 is concave. The second lens E2 has a positive optical power, its near-eye side surface S3 is flat, and its near-screen side surface S4 is convex. The third lens E3 has a negative optical power, its near-eye side surface S5 is concave, and its near-screen side surface S6 is convex. The fourth lens E4 has a positive optical power, its near-eye side surface S7 is convex, and its near-screen side surface S8 is flat. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the near-eye side surface S3 of the second lens E2. The partial reflection element BS is attached to the near-screen side surface S6 of the third lens E3. The second quarter-wave plate QWP2 and the linear polarizing element LP are attached to the near-screen side surface S8 of the fourth lens E4.

[0112] In this example, an image plane IMG can be provided on the second side of the visual system. The image plane IMG can be provided with a display screen, for example. The image light from the image plane IMG sequentially passes through a linear polarization element LP, a second quarter-wave plate QWP2, a fourth lens E4, a third lens E3, a second lens E2, a first quarter-wave plate QWP1 and reaches a reflective polarizing element RP, where a first reflection occurs at the reflective polarizing element RP. The light reflected for the first time passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches a partial reflection element BS on the near-screen side of the third lens E3, where a second reflection occurs at the partial reflection element BS. The light reflected for the second time sequentially passes through the third lens E3, the second lens E2, the first quarter-wave plate QWP1, the reflective polarizing element RP, a first lens E1 to the diaphragm and finally projects into the user's eyes. For example, the light of the visual system after two reflections finally projects into the user's eyes. A protective glass (not shown) can also be provided between the image plane IMG and the linear polarization element LP.

[0113] Table 3 shows the basic parameter table of the visual system of Embodiment 4, where the units of the radius of curvature and the thickness / distance are both millimeters (mm). The image light from the image plane IMG passes through each element in the order from No. 23 to No. 1 and finally projects into the human eyes.

[0114]

[0115] Table 3

[0116] In this embodiment, the near-screen side S4 of the second lens E2, the near-eye side S5 and the near-screen side S6 of the third lens E3, and the near-eye side S7 of the fourth lens E4 are all aspherical surfaces. Table 4 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 for the aspherical surfaces S4 - S7 that can be used in Embodiment 4.

[0117] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S4 4.3326E-02 -3.0161E-03 -4.3411E-05 -1.6166E-05 3.7953E-06 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -3.8479E-01 1.1258E-01 6.1473E-02 -5.1302E-03 -2.5956E-02 -1.5649E-02 -3.6736E-03 0.0000E+00 0.0000E+00 S6 -1.7396E-02 2.4428E-04 -1.4953E-02 -1.7120E-02 -1.2611E-02 -5.6990E-03 -1.2368E-03 0.0000E+00 0.0000E+00 S7 1.3806E-01 6.7857E-04 7.1623E-04 -1.4453E-04 2.9049E-05 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0118] Table 4

[0119] Example 5

[0120] The following refers to Figure 7 to describe the visual system according to Embodiment 5 of the present application.

[0121] As Figure 7As shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0122] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarization element LP arranged in sequence along the optical axis from the first side to the second side. A diaphragm STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0123] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 4, that is, the basic parameter table of the visual system in this embodiment is the same as Table 3, and the aspherical coefficient table is the same as Table 4. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some elements in the lens barrel P0 and the spacer element group are different.

[0124] Example 6

[0125] The following refers to Figure 8 Describe the visual system according to Embodiment 6 of the present application.

[0126] As Figure 8 As shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0127] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarization element LP arranged in sequence along the optical axis from the first side to the second side. A diaphragm STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0128] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 4, that is, the basic parameter table of the visual system in this embodiment is the same as Table 3, and the aspherical coefficient table is the same as Table 4. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some elements in the lens barrel P0 and the spacer element group are different.

[0129] Figure 9A Shows the axial chromatic aberration curve of the visual system of Embodiment 4, 5 or 6, which represents the deviation of the focusing points of light rays of different wavelengths after passing through the visual system. Figure 9BThe astigmatism curve of the visual system according to Embodiment 4, 5 or 6 is shown, which represents the meridional field curvature and sagittal field curvature corresponding to different field angles. Figure 9C The distortion curve of the visual system according to Embodiment 4, 5 or 6 is shown, which represents the distortion magnitude values corresponding to different field angles. Figure 9D The modulation transfer function curve of the visual system according to Embodiment 4, 5 or 6 is shown. According to Figures 9A to 9D it can be known that the visual system given by Embodiment 4, 5 or 6 can achieve good imaging quality.

[0130] Example 7

[0131] The following refers to Figure 10 the visual system according to Embodiment 7 of the present application is described.

[0132] As Figure 10 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed in the lens barrel P0.

[0133] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarizing element LP arranged in sequence along the optical axis from the first side to the second side. A stop STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. The first side surfaces of each element (for example, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the first spacer element P1, the second spacer element P2, and the third spacer element P3) are all referred to as the near-eye side surfaces, and the second side surfaces are all referred to as the near-screen side surfaces.

[0134] The first lens E1 has a positive focal power, its near-eye side surface S1 is convex, and its near-screen side surface S2 is concave. The second lens E2 has a positive focal power, its near-eye side surface S3 is flat, and its near-screen side surface S4 is convex. The third lens E3 has a negative focal power, its near-eye side surface S5 is concave, and its near-screen side surface S6 is convex. The fourth lens E4 has a positive focal power, its near-eye side surface S7 is convex, and its near-screen side surface S8 is flat. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the near-eye side surface S3 of the second lens E2. The partial reflection element BS is attached to the near-screen side surface S6 of the third lens E3. The second quarter-wave plate QWP2 and the linear polarizing element LP are attached to the near-screen side surface S8 of the fourth lens E4.

[0135] In this example, the second side of the visual system may be provided with an image plane IMG, and the image plane IMG may be provided with a display screen, for example. The image light from the image plane IMG sequentially passes through a linear polarization element LP, a second quarter-wave plate QWP2, a fourth lens E4, a third lens E3, a second lens E2, a first quarter-wave plate QWP1 and reaches a reflective polarizing element RP, where a first reflection occurs. The light reflected for the first time passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches a partial reflection element BS on the near-screen side of the third lens E3, where a second reflection occurs. The light reflected for the second time sequentially passes through the third lens E3, the second lens E2, the first quarter-wave plate QWP1, the reflective polarizing element RP, a first lens E1 to the diaphragm and finally projects into the user's eyes. For example, the light of the visual system after two reflections finally projects into the user's eyes. A protective glass (not shown) may also be provided between the image plane IMG and the linear polarization element LP.

[0136] Table 5 shows the basic parameter table of the visual system of Embodiment 7, where the units of the radius of curvature and the thickness / distance are both millimeters (mm). The image light from the image plane IMG passes through each element in the order from No. 23 to No. 1 and finally projects into the human eyes.

[0137]

[0138] Table 5

[0139] In this embodiment, the near-screen side S4 of the second lens E2, the near-eye side S5 and the near-screen side S6 of the third lens E3, and the near-eye side S7 of the fourth lens E4 are all aspherical surfaces. Table 6 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 that can be used for the aspherical surfaces S4 - S7 in Embodiment 7.

[0140] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S4 4.3986E-02 -2.0543E-03 -2.0872E-05 -9.4960E-06 7.6199E-07 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 S5 -1.9456E-01 1.6301E-02 2.0676E-02 -1.3665E-02 -1.6130E-02 -1.2575E-02 -1.2809E-03 0.0000E+00 0.0000E+00 S6 1.9752E-02 -4.9490E-03 -7.2719E-03 -1.1055E-02 -6.8125E-03 -4.4695E-03 -5.0325E-04 0.0000E+00 0.0000E+00 S7 8.6077E-02 8.7608E-04 -1.6652E-04 -1.7153E-04 1.1682E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0141] Table 6

[0142] Example 8

[0143] The following refers to Figure 11 to describe the visual system according to Embodiment 8 of the present application.

[0144] As Figure 11As shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0145] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarization element LP arranged in sequence along the optical axis from a first side to a second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0146] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 7, that is, the basic parameter table of the visual system in this embodiment is the same as Table 5, and the aspherical coefficient table is the same as Table 6. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some of the elements in the lens barrel P0 and the spacer element group are different.

[0147] Example 9

[0148] The following refers to Figure 12 Describe the visual system according to Embodiment 9 of the present application.

[0149] As Figure 12 As shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group disposed within the lens barrel P0.

[0150] The optical element group may include a first lens E1, a reflective polarizing element RP, a first quarter-wave plate QWP1, a second lens E2, a third lens E3, a partial reflection element BS, a fourth lens E4, a second quarter-wave plate QWP2, and a linear polarization element LP arranged in sequence along the optical axis from a first side to a second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3.

[0151] The structure of the optical element group in this embodiment is the same as that of the optical element group in Embodiment 7, that is, the basic parameter table of the visual system in this embodiment is the same as Table 5, and the aspherical coefficient table is the same as Table 6. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some of the elements in the lens barrel P0 and the spacer element group are different.

[0152] Figure 13A Shows the axial chromatic aberration curve of the visual system of Embodiment 7, 8, or 9, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the visual system. Figure 13BShows the astigmatism curves of the visual systems of Examples 7, 8, or 9, which represent the meridional field curvature and sagittal field curvature corresponding to different field angles. Figure 13C Shows the distortion curves of the visual systems of Examples 7, 8, or 9, which represent the distortion magnitude values corresponding to different field angles. Figure 13D Shows the modulation transfer function curves of the visual systems of Examples 7, 8, or 9. According to Figures 13A to 13D It can be seen that the visual systems given in Examples 7, 8, or 9 can achieve good imaging quality.

[0153] Table 7 gives the values of parameters such as f, f1, f2, f3, f4, fz1, fz2, etc. for each of Examples 1 - 9. Among them, the units of f, f1, f2, f3, f4, fz1, fz2 in Table 7 are all millimeters (mm).

[0154] Parameter / Example 1 2 3 4 5 6 7 8 9 f 42.00 42.00 42.00 41.50 41.50 41.50 41.50 41.50 41.50 f1 32.00 32.00 32.00 85.14 85.14 85.14 100.00 100.00 100.00 f2 79.62 79.62 79.62 191.39 191.39 191.39 200.00 200.00 200.00 f3 -63.48 -63.48 -63.48 -114.15 -114.15 -114.15 -146.25 -146.25 -146.25 f4 -28.43 -28.43 -28.43 32.78 32.78 32.78 38.83 38.83 38.83 fz1 25.09 25.09 25.09 60.94 60.94 60.94 68.81 68.81 68.81 fz2 -18.56 -18.56 -18.56 45.10 45.10 45.10 52.04 52.04 52.04

[0155] Table 7

[0156] Table 8 gives the values of parameters such as d1s, D1s, D1m, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, d0s, d0m, D0s, D0m, EP01, CP1, EP12, CP2, EP23, CP3, and L for each of Examples 1 - 9. Among them, the above parameters can be measured according to the Figure 1 indicated marking method, and the units of the parameters listed in Table 8 are all millimeters (mm).

[0157]

[0158]

[0159] Table 8

[0160] In summary, Table 9 shows the conditional values of each of Examples 1 to 9.

[0161] Conditional expression / Example 1 2 3 4 5 6 7 8 9 f2 / f3 -1.25 -1.25 -1.25 -1.68 -1.68 -1.68 -1.37 -1.37 -1.37 R4 / d2s -1.59 -1.59 -1.61 -3.42 -3.42 -3.42 -3.57 -3.57 -3.57 R5 / d2m -2.09 -2.09 -2.12 -1.71 -1.68 -1.68 -1.94 -1.94 -1.96 (EP01 + CP1) / CT1 0.55 0.55 0.55 0.71 0.71 0.66 0.80 0.80 0.80 f3 / (d3s + D3s) -1.43 -1.43 -1.43 -2.24 -2.24 -2.22 -2.79 -2.79 -2.78 f / L 1.97 1.97 1.97 1.89 1.89 1.90 1.86 1.86 1.86 (EP23 + CP3) / CT3 1.25 1.24 1.24 2.10 1.98 1.90 1.88 1.76 1.70 (CTR + CTQ1 + CT2) / EP12 2.35 2.35 2.35 2.31 2.31 2.31 2.22 2.22 2.22 T23 / CP2 0.14 0.14 0.14 1.07 1.06 1.06 1.05 1.04 1.04 d0s / d0m 2.10 2.10 2.10 1.94 1.94 1.94 1.97 1.97 1.97 fz1 / (D1s + D1m) 0.45 0.45 0.45 1.02 1.02 1.02 1.15 1.15 1.15 D0s / R1 1.83 1.83 1.83 1.61 1.61 1.61 1.55 1.55 1.55 |fz2| / d3m 1.01 1.01 1.01 1.95 1.95 1.91 2.19 2.19 2.17 (D2s + D2m) / D0m 1.84 1.85 1.85 2.75 2.77 2.77 2.81 2.81 2.81 d1s / f1 0.84 0.84 0.83 0.32 0.32 0.32 0.27 0.27 0.27 |f4| / D3m 1.09 1.09 1.09 1.18 1.18 1.18 1.36 1.36 1.36

[0162] Table 9

[0163] This application also provides an optical device, which can be an independent projection device such as a projector, or a projection module integrated on a mobile electronic device such as a virtual reality device. This optical device is equipped with the visual system described above.

[0164] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) disclosed in the present application that have similar functions.

Claims

1. A visual system, characterized in that: include: An optical element group, comprising a first lens with positive optical power, a reflective polarizing element, a first quarter wave plate, a second lens with positive optical power, a third lens with negative optical power, a partial reflecting element, a fourth lens with optical power, a second quarter wave plate and a linear polarizing element arranged in sequence from a first side to a second side along an optical axis; a spacer element group, comprising a second spacer element, the second spacer element being disposed on a second side surface of the second lens and in contact with the second side surface of the second lens; as well as A lens barrel, wherein the optical element group and the spacer element group are placed in the lens barrel; Wherein, the number of lenses with optical power in the visual system is four; The effective focal length f2 of the second lens and the effective focal length f3 of the third lens satisfy: -1.7 <f2 / f3<-1.2; The curvature radius R4 of the second side surface of the second lens and the inner diameter d2s of the first side surface of the second spacing element satisfy: -3.6 <R4 / d2s≤-1.59; A curvature radius R5 of the first side surface of the third lens and an inner diameter d2m of the second side surface of the second spacing element satisfy: -2.12≤R5 / d2m≤-1.

68.

2. The visual system according to claim 1, characterized in that: The total effective focal length f of the visual system and the length L of the lens barrel along the direction of the optical axis satisfy the following conditions: 1.86≤f / L<2.

0.

3. The visual system according to claim 1, characterized in that: The axial distance T23 from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness CP2 of the second spacer element satisfy: 0.1 <T23 / CP2<1.1。 4. The visual system according to claim 1, characterized in that: The inner diameter d0s of the first side end surface of the lens barrel and the inner diameter d0m of the second side end surface of the lens barrel satisfy: 1.9 <d0s / d0m≤2.1。 5. The visual system according to claim 1, characterized in that: The outer diameter D0s of the first side end surface of the lens barrel and the curvature radius R1 of the first side surface of the first lens satisfy: 1.5 <D0s / R1≤1.83。 6. The visual system according to claim 1, characterized in that: An outer diameter D2s of the first side surface of the second spacing element, an outer diameter D2m of the second side surface of the second spacing element, and an outer diameter D0m of the second side end surface of the lens barrel satisfy the following: 1.8<(D2s+D2m) / D0m≤2.

81.

7. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a first spacer element, the first spacer element being disposed on a second side surface of the first lens and in contact with the second side surface of the first lens; The spacing distance EP01 between the first side end surface of the lens barrel and the first spacing element along the optical axis, the maximum thickness CP1 of the first spacing element and the center thickness CT1 of the first lens on the optical axis satisfy: 0.5<(EP01+CP1) / CT1≤0.

8.

8. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a first spacer element, the first spacer element being disposed on a second side surface of the first lens and in contact with the second side surface of the first lens; Among them, the center thickness CTR of the reflective polarizing element on the optical axis, the center thickness CTQ1 of the first quarter wave plate on the optical axis, the center thickness CT2 of the second lens on the optical axis and the spacing distance EP12 between the first spacing element and the second spacing element along the optical axis satisfy: 2.2<(CTR+CTQ1+CT2) / EP12<2.

4.

9. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a first spacer element, the first spacer element being disposed on a second side surface of the first lens and in contact with the second side surface of the first lens; The combined focal length fz1 of the first lens, the reflective polarizing element, the first quarter wave plate and the second lens, the outer diameter D1s of the first side surface of the first spacing element and the outer diameter D1m of the second side surface of the first spacing element satisfy the following conditions: 0.4 <fz1 / (D1s+D1m)<1.2。 10. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a first spacer element, the first spacer element being disposed on a second side surface of the first lens and in contact with the second side surface of the first lens; The effective focal length f1 of the first lens and the inner diameter d1s of the first side surface of the first spacing element satisfy: 0.27≤d1s / f1≤0.

84.

11. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a third spacer element, the third spacer element being disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The effective focal length f3 of the third lens, the inner diameter d3s of the first side surface of the third spacing element and the outer diameter D3s of the first side surface of the third spacing element satisfy: -2.8 <f3 / (d3s+D3s)<-1.4。 12. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a third spacer element, the third spacer element being disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The spacing distance EP23 between the second spacing element and the third spacing element along the optical axis, the maximum thickness CP3 of the third spacing element and the center thickness CT3 of the third lens on the optical axis satisfy: 1.2<(EP23+CP3) / CT3≤2.

1.

13. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a third spacer element, the third spacer element being disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The combined focal length fz2 of the third lens, the fourth lens, the second quarter wave plate and the linear polarization element and the inner diameter d3m of the second side surface of the third spacing element satisfy: 1.0<|fz2| / d3m<2.

2.

14. The visual system according to any one of claims 1 to 6, characterized in that: The spacer element group further includes a third spacer element, the third spacer element being disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The effective focal length f4 of the fourth lens and the outer diameter D3m of the second side surface of the third spacing element satisfy: 1.09≤|f4| / D3m<1.

4.

15. The visual system according to any one of claims 1 to 6, characterized in that: The first quarter wave plate is disposed on a first side surface of the second lens; The reflective polarizing element is disposed on a first side surface of the first quarter-wave plate; The partial reflective element is disposed on the second side surface of the third lens; The second quarter wave plate is disposed on the second side surface of the fourth lens; and The linear polarization element is arranged on the second side surface of the second quarter wave plate.

16. The visual system according to any one of claims 1 to 6, characterized in that: The first side surface of the first lens is a convex surface, and the second side surface is a concave surface; The first side surface of the second lens is a plane surface, and the second side surface is a convex surface; The first side surface of the third lens is a concave surface; The second side surface of the fourth lens is a plane.

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