Visual system

Abstract

The utility model discloses a visual system. The visual system comprises a lens cone, a spacing element group and an optical element group, wherein the spacing element group and the optical element group are assembled in the lens cone. The optical element set sequentially comprises a first lens with positive focal power, a reflective polarizing element, a first quarter-wave plate, a second lens with positive focal power, a third lens with negative focal power, a partial reflection element, a second quarter-wave plate, a polarizing film and a fourth lens with positive focal power from the first side to the second side along the optical axis. The spacer element group includes a second spacer element disposed on and in contact with a second side of the second lens. Wherein 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 spacing element along the optical axis direction meet the following conditions: 1.0 lt; t23 / CP2lt, T23 / CP2lt; 1.25, 1.25; the inner diameter d2s of the first side surface of the second spacing element, the outer diameter D2s of the first side surface of the second spacing element and the combined focal length fz1 of the reflective polarizing element, the first quarter-wave plate and the second lens meet the following conditions: 0.05 lt; (d2s + D2s) / fz1lt; and 0.4 part.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and in particular to a visual 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. Early visual systems mainly used aspherical lenses or Fresnel lenses, which had a long body length and the user's center of gravity was forward when worn, thus affecting the user's experience.

[0003] The catadioptric optical system is a major innovation in the visual system itself. It reserves space for the overall design of virtual reality devices or augmented reality devices and has become a mainstream trend in research and development. 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 blurry and the image quality to be poor. Utility Model Content

[0004] One aspect of the present application provides a visual system, which includes a lens barrel and a spacing element group and an optical element group assembled in the lens barrel. The optical element group includes a first lens with positive focal power, a reflective polarizing element, a first quarter-wave plate, a second lens with positive focal power, a third lens with negative focal power, a partial reflection element, a second quarter-wave plate, a polarizer and a fourth lens with positive focal power in sequence from the first side to the second side along the optical axis. The spacing element group includes a second spacing element placed on the second side of the second lens and in contact with the second side of the second lens. Among them, the on-axis distance T23 from the second side of the second lens to the first side of the third lens and the maximum thickness CP2 of the second spacing element along the optical axis satisfy: 1.0 <T23 / CP2<1.25;第二间隔元件的第一侧面的内径d2s、第二间隔元件的第一侧面的外径D2s与反射式片偏光元件、第一四分之一波片和第二透镜的组合焦距fz1满足:0.05<(d2s+D2s) / fz1<0.4。

[0005] According to an exemplary embodiment of the present application, the inner diameter d0s of the first side end surface of the lens barrel, the outer diameter D0s of the first side end surface of the lens barrel, and the effective focal length f1 of the first lens satisfy: 1.25<(d0s+D0s) / f1<1.7.

[0006] According to an exemplary embodiment of the present application, the total effective focal length f of the visual system and the distance L along the optical axis between the first side end face of the lens barrel and the second side end face of the lens barrel satisfy: 1.35 < f / L < 1.55.

[0007] According to an exemplary embodiment of the present application, the outer diameter D2m of the second side face of the second spacer element and the effective focal length f3 of the third lens satisfy: -0.3 < D2m / f3 < -0.1.

[0008] According to an exemplary embodiment of the present application, the inner diameter d0m of the second side end face of the lens barrel and the combined focal length fz2 of the second quarter-wave plate, the polarizer, and the fourth lens satisfy: 0.1 < d0m / fz2 < 0.5.

[0009] According to an exemplary embodiment of the present application, the radius of curvature R5 of the first side face of the third lens and the inner diameter d2m of the second side face of the second spacer element satisfy: -3.1 < R5 / d2m < -1.8.

[0010] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on the second side face of the first lens and in contact with the second side face of the first lens. The outer diameter D1s of the first side face of the first spacer element, the outer diameter D1m of the second side face of the first spacer element, and the radius of curvature R2 of the second side face of the first lens satisfy: 1.0 < (D1s + D1m) / R2 < 1.9.

[0011] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on the second side face of the first lens and in contact with the second side face of the first lens, and a third spacer element disposed on the second side face of the third lens and in contact with the second side face of the third lens. The maximum thickness CP1 of the first spacer element in the optical axis direction and the maximum thickness CP3 of the third spacer element in the optical axis direction satisfy: 0.5 < CP3 / CP1 < 2.25.

[0012] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on the second side face of the first lens and in contact with the second side face of the first lens. The distance EP12 between the first spacer element and the second spacer element along the optical axis, 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, and the central thickness CT2 of the second lens on the optical axis satisfy: 0.55 < EP12 / (CTR + CTQ1 + CT2) < 1.0.

[0013] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on and in contact with the second side surface of the third lens. The radius of curvature R6 of the second side surface of the third lens and the outer diameter D3s of the first side surface of the third spacer element satisfy: -5.5 < R6 / D3s < -3.65.

[0014] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on and in contact with the second side surface of the first lens. The on-axis distance TD from the first side surface of the first lens to the second side surface of the fourth lens and the distance EP01 from the first side end surface of the lens barrel to the first spacer element along the optical axis satisfy: 2.55 < TD / EP01 < 3.25.

[0015] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on and in contact with the second side surface of the third lens. The distance EP23 between the second spacer element and the third spacer element along the optical axis, the central thickness CTQ2 of the second quarter-wave plate on the optical axis, the central thickness CTL of the polarizer on the optical axis, and the central thickness CT4 of the fourth lens on the optical axis satisfy: 2.85 < EP23 / (CTQ2 + CTL + CT4) < 4.1.

[0016] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on and in contact with the second side surface of the third lens. The outer diameter D0m of the second side end surface of the lens barrel and the outer diameter D3m of the second side surface of the third spacer element satisfy: 0.8 < D0m / D3m < 1.2.

[0017] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on and in contact with the second side surface of the first lens. The inner diameter d1s of the first side surface of the first spacer element and the central thickness CT1 of the first lens on the optical axis satisfy: 4.5 < d1s / CT1 < 5.7.

[0018] According to an exemplary embodiment of the present application, the spacer element group further includes a first spacer element disposed on and in contact with the second side surface of the first lens. The inner diameter d1m of the second side surface of the first spacer element and the on-axis distance T12 from the second side surface of the first lens to the first side surface of the second lens satisfy: 10.75 ≤ d1m / T12 < 16.25.

[0019] According to an exemplary embodiment of the present application, the spacer element group further includes a third spacer element disposed on and in contact with the second side surface of the third lens. The inner diameter d3s of the first side surface of the third spacer element, the inner diameter d3m of the second side surface of the third spacer element, and the effective focal length f4 of the fourth lens satisfy: 0.15 < (d3s + d3m) / f4 < 0.8.

[0020] The visual system provided by the present application uses four lenses. Reasonably configuring the optical powers of the four lenses is beneficial to improving the imaging quality of the visual system. Moreover, by coordinating and restricting the relationship between the on-axis distance from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness of the second spacer element, as well as the relationship between the inner diameter of the first side surface of the second spacer element, the outer diameter of the first side surface of the second spacer element, and the combined focal length of the reflective sheet polarizing element, the first quarter-wave plate, and the second lens, the shapes of the second side surface of the second lens and the first side surface of the third lens can be effectively controlled, ensuring good processability of the second lens and the third lens. At the same time, the second spacer element can also have good strength and forming conditions, ensuring stable bearing between the second lens, the third lens, and the second spacer element, and improving the assembly stability and assembly yield of the visual system. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] Figure 1 Shows a parameter annotation diagram of a visual system according to an embodiment of the present application;

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

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

[0025] Figure 4 Shows a schematic structural diagram of a visual system according to Embodiment 3 of the present 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 curve of the visual systems according to Embodiments 1, 2, and 3 of the present application;

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

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

[0029] Figure 8 Shows a schematic structural diagram of a visual system according to Embodiment 6 of the present 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 Embodiments 4, 5, and 6 of the present application;

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

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

[0033] Figure 12 Shows a schematic structural diagram of a 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 Embodiments 7, 8, and 9 of the present application. Detailed implementation manners

[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. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0036] It should be noted that in this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature and do not represent any limitation on the feature. 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 ease of illustration, the thickness, size, and shape of the lens 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 document, 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 object to be photographed is called the first side of the lens, and the surface of each lens closest to the image plane is called the second side of the lens.

[0039] It should also be understood that the terms "comprising" and / or "having", 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 used herein (including technical and scientific terms) 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 in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0042] Figure 1 It is a parameter annotation diagram according to an exemplary embodiment of the present application. Refer to Figure 1, D0s represents the outer diameter of the first side end face of the lens barrel, D0m represents the outer diameter of the second side end face of the lens barrel, d0s represents the inner diameter of the first side end face of the lens barrel, d0m represents the inner diameter of the second side end face of the lens barrel, D1s represents the outer diameter of the first side face of the first spacer element, D1m represents the outer diameter of the second side face of the first spacer element, d1s represents the inner diameter of the first side face of the first spacer element, d1m represents the inner diameter of the second side face of the first spacer element, D2s represents the outer diameter of the first side face of the second spacer element, D2m represents the outer diameter of the second side face of the second spacer element, d2m represents the inner diameter of the second side face of the second spacer element, d2s represents the inner diameter of the first side face of the second spacer element, D3s represents the outer diameter of the first side face of the third spacer element, D3m represents the outer diameter of the second side face of the third spacer element, d3s represents the inner diameter of the first side face of the third spacer element, d3m represents the inner diameter of the second side face of the third spacer element, EP01 represents the distance along the optical axis between the first side end face of the lens barrel and the first spacer element, CP1 represents the maximum thickness of the first spacer element along the optical axis direction, EP12 represents the distance along the optical axis between the first spacer element and the second spacer element, CP2 represents the maximum thickness of the second spacer element along the optical axis direction, EP23 represents the distance along the optical axis between the second spacer element and the third spacer element, CP3 represents the maximum thickness of the third spacer element along the optical axis direction, and L represents the distance along the optical axis between the first side end face of the lens barrel and the second side end face of the lens barrel.

[0043] The first aspect of the present application provides a visual system that may include an optical element group. 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 second quarter-wave plate, a polarizer, and a fourth lens 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.

[0045] In an exemplary embodiment, the first quarter-wave plate may be placed on the first side face of the second lens and at least partially adhered to the first side face of the second lens. The reflective polarizing element may be placed on the first side face of the first quarter-wave plate and at least partially adhered to the first side face of the first quarter-wave plate. The partial reflection element may be placed on the second side face of the third lens and at least partially adhered to the second side face of the third lens. The polarizer may be placed on the first side face of the fourth lens and at least partially adhered to the first side face of the fourth lens. The second quarter-wave plate may be placed on the first side face of the polarizer and at least partially adhered to the first side face of the polarizer.

[0046] In an exemplary embodiment, the visual system may further include a diaphragm, which may be disposed on the first side of the first lens. As an example, the diaphragm may be, for example, the pupil of the user. The image light from the second side passes through the fourth lens, the polarizer, the second quarter-wave plate, the partially reflecting element, the third lens, the second lens, the first quarter-wave plate, the reflective polarizing element, the first lens, etc., and is finally projected onto the user's eye on the first side after multiple refractions and reflections.

[0047] In an exemplary embodiment, the first side may be, for example, the human eye side, and the second side may be, for example, the display screen side. Correspondingly, the first side surfaces of the respective elements (such as the first lens, the second lens, the third lens, the fourth lens, the first quarter-wave plate, the second quarter-wave plate) may be referred to as the near-eye side surfaces, and the second side surfaces may be referred to as the near-screen side surfaces.

[0048] In an exemplary embodiment, an image plane may be disposed on the second side of the visual system, and a display screen may be disposed on the image plane. The light from the display screen sequentially passes through the fourth lens, the polarizer, the second quarter-wave plate, the third lens, the second lens, the first quarter-wave plate, reaches the reflective polarizing element, and then is reflected at the reflective polarizing element to form the first reflected image light. The first reflected image light sequentially passes through the first quarter-wave plate, the second lens, the third lens and reaches the partially reflecting element on the second side surface of the third lens, and then is reflected at the partially reflecting 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 is finally projected onto the user's eye. 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.

[0049] In an exemplary embodiment, the visual system may further include a spacer element group. The spacer element group may include one or more of a first spacer element, a second spacer element, and a third spacer element. Reasonable use of the spacer elements can effectively avoid the risk of stray light, reduce the interference to the image quality, and thus improve the imaging quality of the visual system.

[0050] In an exemplary embodiment, the visual system may further include a lens barrel. The optical element group and the spacer element group are disposed in the lens barrel. Among them, the end surface of the lens barrel closest to the first side is the first side end surface of the lens barrel, and the end surface of the lens barrel closest to the second side is the second side end surface of the lens barrel.

[0051] In an exemplary embodiment, the spacer element group may include a second spacer element. 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 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 in the optical axis direction may satisfy: 1.0 < T23 / CP2 < 1.25; the inner diameter d2s of the first side surface of the second spacer element, the outer diameter D2s of the first side surface of the second spacer element, and the combined focal length fz1 of the reflective sheet polarizing element, the first quarter-wave plate, and the second lens may satisfy: 0.05 < (d2s + D2s) / fz1 < 0.4. Reasonably configuring the relationship between the axial distance from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness of the second spacer element, and the relationship between the inner diameter of the first side surface of the second spacer element, the outer diameter of the first side surface of the second spacer element, and the combined focal length of the reflective sheet polarizing element, the first quarter-wave plate, and the second lens can effectively control the shapes of the second side surface of the second lens and the first side surface of the third lens, ensure good processability of the second lens and the third lens, and at the same time enable the second spacer element to have good strength and forming conditions, ensure stable bearing between the second lens, the third lens, and the second spacer element, and improve the assembly stability and assembly yield of the visual system.

[0052] In an exemplary embodiment, the inner diameter d0s of the first side end surface of the lens barrel, the outer diameter D0s of the first side end surface of the lens barrel, and the effective focal length f1 of the first lens may satisfy: 1.25 < (d0s + D0s) / f1 < 1.7. Reasonably configuring the relationship between the inner diameter of the first side end surface of the lens barrel, the outer diameter of the first side end surface of the lens barrel, and the effective focal length of the first lens is beneficial to restricting the light passing amount of the visual system, keeping the field of view angle of the visual system within a reasonable range, and at the same time ensuring that the aberration of the first lens is at a reasonable level, which is conducive to improving the imaging quality of the visual system on the basis of ensuring good processability of the lens barrel.

[0053] In an exemplary embodiment, the total effective focal length f of the visual system and the distance L along the optical axis between the first side end surface and the second side end surface of the lens barrel may satisfy: 1.35 < f / L < 1.55. Reasonably configuring the ratio of the total effective focal length of the visual system to the distance along the optical axis between the first side end surface and the second side end surface of the lens barrel can make the aberration of the visual system at a reasonable level, thereby improving the imaging quality of the visual system, and at the same time can also restrict the distance along the optical axis between the first side end surface and the second side end surface of the lens barrel, which is beneficial to realizing the miniaturization of the visual system.

[0054] In an exemplary embodiment, the spacer element group may include a second spacer element. 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 outer diameter D2m of the second side surface of the second spacer element and the effective focal length f3 of the third lens may satisfy: -0.3 < D2m / f3 < -0.1. Reasonably configuring the ratio of the outer diameter of the second side surface of the second spacer element to the effective focal length of the third lens helps to control the assembly step difference among the second lens, the third lens, and the second spacer element, improving the assembly stability of the visual system; meanwhile, it also helps to control the aberration of the visual system at a reasonable level, improving the imaging quality of the visual system.

[0055] In an exemplary embodiment, the inner diameter d0m of the second side end surface of the lens barrel and the combined focal length fz2 of the second quarter-wave plate, the polarizer, and the fourth lens may satisfy: 0.1 < d0m / fz2 < 0.5. Reasonably configuring the ratio of the inner diameter of the second side end surface of the lens barrel to the combined focal length of the second quarter-wave plate, the polarizer, and the fourth lens can enable the visual system to have a wider field of view angle, ensuring that users can see more display content, such as virtual reality content or augmented reality content; meanwhile, it can also restrict the light beam path, reduce stray light, and improve the imaging quality of the visual system.

[0056] In an exemplary embodiment, the spacer element group may include a second spacer element. 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 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 spacer element may satisfy: -3.1 < R5 / d2m < -1.8. Reasonably configuring the ratio of the curvature radius of the first side surface of the third lens to the inner diameter of the second side surface of the second spacer element can effectively control the shape of the third lens within a reasonable range, thereby improving the processability of the third lens.

[0057] In an exemplary embodiment, the spacer element group may include a first 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 outer diameter D1s of the first side surface of the first spacer element, the outer diameter D1m of the second side surface of the first spacer element, and the curvature radius R2 of the second side surface of the first lens may satisfy: 1.0 < (D1s + D1m) / R2 < 1.9. Reasonably configuring the relationship among the outer diameter of the first side surface of the first spacer element, the outer diameter of the second side surface of the first spacer element, and the curvature radius of the second side surface of the first lens can utilize the buffering characteristics of the material of the first spacer element to effectively prevent the reflective polarizing element from directly contacting the first lens, reducing the assembly stress between the first lens and the second lens, improving the anti-vibration ability and drop reliability of the visual system, and meanwhile, it also helps to reduce the sensitivity of the first lens, improving the assembly yield of the visual system.

[0058] In an exemplary embodiment, the spacer element group may include a first 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 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. The maximum thickness CP1 of the first spacer element in the optical axis direction and the maximum thickness CP3 of the third spacer element in the optical axis direction may satisfy: 0.5 < CP3 / CP1 < 2.25. Reasonably configuring the ratio of the maximum thickness of the first spacer element in the optical axis direction to the maximum thickness of the third spacer element in the optical axis direction is beneficial to ensuring the forming strength of the first spacer element and the third spacer element, avoiding using spacer elements with larger thicknesses, and improving the assembly stability of the visual system.

[0059] In an exemplary embodiment, the spacer element group may include a first spacer element and a second 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 distance EP12 between the first spacer element and the second spacer element along the optical axis, 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, and the central thickness CT2 of the second lens on the optical axis may satisfy: 0.55 < EP12 / (CTR + CTQ1 + CT2) < 1.0. Reasonably controlling the relationship between the distance between the first spacer element and the second spacer element along the optical axis, the central thickness of the reflective polarizing element on the optical axis, the central thickness of the first quarter-wave plate on the optical axis, and the central thickness of the second lens on the optical axis can achieve a compact design of the visual system, reduce the volume and weight of the visual system and the device including the visual system, improve the wearing convenience of the device including the visual system, and at the same time, the edge thickness of the second lens can be controlled to improve the processability of the second lens.

[0060] In an exemplary embodiment, the spacer element group may include a third spacer element. 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. The radius of curvature R6 of the second side surface of the third lens and the outer diameter D3s of the first side surface of the third spacer element may satisfy: -5.5 < R6 / D3s < -3.65. Reasonably configuring the ratio of the radius of curvature of the second side surface of the third lens to the outer diameter of the first side surface of the third spacer element is beneficial to restricting the shape of the third lens, thereby improving the processability of the third lens.

[0061] In an exemplary embodiment, the spacer element group may include a first 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 axial distance TD from the first side surface of the first lens to the second side surface of the fourth lens and the distance EP01 from the first side end surface of the lens barrel to the first spacer element along the optical axis may satisfy: 2.55 < TD / EP01 < 3.25. Reasonably configuring the ratio of the axial distance from the first side surface of the first lens to the second side surface of the fourth lens to the distance from the first side end surface of the lens barrel to the first spacer element along the optical axis is conducive to meeting the appearance requirements of the lens barrel on the basis of ensuring the performance of the visual system, thereby realizing the miniaturization of the visual system. At the same time, the edge thickness of the first lens can be controlled to ensure that the first lens has good processability and avoid the first lens being easily scratched due to the first lens protruding from the first side end surface of the lens barrel.

[0062] In an exemplary embodiment, the spacer element group may include a second spacer element and a third spacer element. 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. The distance EP23 between the second spacer element and the third spacer element along the optical axis, the central thickness CTQ2 of the second quarter-wave plate on the optical axis, the central thickness CTL of the polarizer on the optical axis, and the central thickness CT4 of the fourth lens on the optical axis may satisfy: 2.85 < EP23 / (CTQ2 + CTL + CT4) < 4.1. Reasonably configuring the relationship between the distance between the second spacer element and the third spacer element along the optical axis, the central thickness of the second quarter-wave plate on the optical axis, the central thickness of the polarizer on the optical axis, and the central thickness of the fourth lens on the optical axis can enable the second quarter-wave plate, the polarizer, and the fourth lens to have good strength, reduce the bonding difficulty between the second quarter-wave plate and the polarizer, and improve the assembly yield of the visual system.

[0063] In an exemplary embodiment, the spacer element group may include a third spacer element. 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. The outer diameter D0m of the second side end surface of the lens barrel and the outer diameter D3m of the second side surface of the third spacer element may satisfy: 0.8 < D0m / D3m < 1.2. Reasonably configuring the ratio of the outer diameter of the second side end surface of the lens barrel to the outer diameter of the second side surface of the third spacer element is conducive to restricting the outer diameters of the third lens and the fourth lens. On the basis of ensuring that the third lens and the fourth lens have a sufficiently wide mechanism part (for example, the non-effective diameter part), the wall thickness of the lens barrel is appropriate, improving the processability of the lens barrel; at the same time, the external dimensions of the lens barrel can be controlled to meet the requirements of the module end and realize the miniaturization of the visual system.

[0064] In an exemplary embodiment, the spacer element group may include a first 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 inner diameter d1s of the first side surface of the first spacer element and the central thickness CT1 of the first lens on the optical axis may satisfy: 4.5 < d1s / CT1 < 5.7. By reasonably configuring the ratio of the inner diameter of the first side surface of the first spacer element to the central thickness of the first lens on the optical axis, the angle and position of the incident light can be effectively controlled, and the optical performance of the first lens can be optimized, such as reducing system aberration, improving imaging quality, and overall optical characteristics; at the same time, the inner diameter of the first side surface of the first spacer element can also be restricted, so that the first spacer element effectively blocks the stray light at the first lens and improves the imaging quality of the visual system.

[0065] In an exemplary embodiment, the spacer element group may include a first 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 inner diameter d1m of the second side surface of the first spacer element and the axial distance T12 from the second side surface of the first lens to the first side surface of the second lens may satisfy: 10.75 ≤ d1m / T12 < 16.25. By reasonably configuring the ratio of the inner diameter of the second side surface of the first spacer element to the axial distance from the second side surface of the first lens to the first side surface of the second lens, it is beneficial to control the shapes of the second side surface of the first lens and the first side surface of the second lens, and improve the processability of the first lens and the second lens.

[0066] In an exemplary embodiment, the spacer element group may include a third spacer element. 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. The inner diameter d3s of the first side surface of the third spacer element, the inner diameter d3m of the second side surface of the third spacer element, and the effective focal length f4 of the fourth lens may satisfy: 0.15 < (d3s + d3m) / f4 < 0.8. By reasonably configuring the relationship between the inner diameter of the first side surface of the third spacer element, the inner diameter of the second side surface of the third spacer element, and the effective focal length of the fourth lens, it helps to ensure the refraction and focusing effects of light inside the fourth lens, optimize the design of the fourth lens, make the propagation of light inside the fourth lens more appropriate and effective, and at the same time, the third spacer element can also effectively block the stray light and improve the imaging quality of the visual system.

[0067] In an exemplary embodiment, the visual system may further include a filter for correcting color deviation and / or a protective glass for protecting the photosensitive element located on the image plane.

[0068] In an exemplary embodiment, one or more aspherical mirrors may be included in the mirrors of the first lens, the second lens, the third lens, and the fourth lens. The aspherical mirror has more curvature radius characteristics and has the advantages of improving distortion aberration and improving aberration. By using the aspherical mirror, it is possible to eliminate as much as possible the aberration that occurs during imaging, thereby improving the imaging quality.

[0069] On the other hand, the present application provides a visual system including a lens barrel and a spacer element group and an optical element group assembled in the lens barrel. The optical element group sequentially includes 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 partial reflection element, a second quarter-wave plate, a polarizer, and a fourth lens with a positive optical power along the optical axis from the first side to the second side. The spacer element group includes a first spacer element and a second spacer element. The first spacer element is placed on the second side surface of the first lens and is in contact with the second side surface of the first lens. The second spacer element is placed on the second side surface of the second lens and is in contact with the second side surface of the second lens.

[0070] 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 in the optical axis direction may satisfy: 1.0 < T23 / CP2 < 1.25; the outer diameter D1s of the first side surface of the first spacer element, the outer diameter D1m of the second side surface of the first spacer element, and the curvature radius R2 of the second side surface of the first lens may satisfy: 1.0 < (D1s + D1m) / R2 < 1.9. By reasonably configuring the relationship between the on-axis distance from the second side surface of the second lens to the first side surface of the third lens and the maximum thickness of the second spacer element, and the outer diameter of the first side surface of the first spacer element, the outer diameter of the second side surface of the first spacer element, and the curvature radius of the second side surface of the first lens, it is possible to effectively control the shapes of the second side surface of the second lens and the first side surface of the third lens, ensure good processability of the second lens and the third lens; at the same time, the buffering characteristics of the material of the first spacer element can be utilized to effectively avoid direct contact between the reflective polarizing element and the first lens, reduce the assembly stress between the first lens and the second lens, improve the anti-vibration ability and drop reliability of the visual system, and also help to reduce the sensitivity of the first lens and improve the assembly yield of the visual system.

[0071] Those skilled in the art should understand that without departing from the technical solutions claimed in the present application, the number of lenses and spacer elements constituting the visual system can be changed to obtain the various results and advantages described in this specification.

[0072] The following further describes specific embodiments of the visual system applicable to the above embodiments with reference to the accompanying drawings.

[0073] Example 1

[0074] The following refers to Figure 2 Describe the visual system according to Embodiment 1 of the present application.

[0075] As Figure 2 shown, the visual system may include a barrel P0 and an optical element group and a spacer element group assembled in the barrel P0.

[0076] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. The aperture STO is disposed 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. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surface of each element is also referred to as the near-human-eye side surface, and the second side surface is also referred to as the near-screen side surface.

[0077] The first lens E1 has a positive optical power, its first side surface S1 is convex, and its second side surface S2 is concave. The second lens E2 has a positive optical power, its first side surface S3 is flat, and its second side surface S4 is convex. The third lens E3 has a negative optical power, its first side surface S5 is concave, and its second side surface S6 is convex. The fourth lens E4 has a positive optical power, its first side surface S7 is flat, and its second side surface S8 is convex. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the first side surface S3 of the second lens E2. The partial reflection element BS is attached to the second side surface S6 of the third lens E3. The second quarter-wave plate QWP2 and the polarizer LP are attached to the first side surface S7 of the fourth lens E4. It should be noted that the surfaces S1 to S8 are not shown in Figure 2 shown.

[0078] In this example, an image plane IMG may be provided on the second side of the visual system, and a display screen may be provided on the image plane IMG. The light from the display screen sequentially passes through the fourth lens E4, the polarizer LP, the second quarter-wave plate QWP2, the third lens E3, the second lens E2, the first quarter-wave plate QWP1, reaches the reflective polarizing element RP, and then is reflected at the reflective polarizing element RP to form the first reflected image light. The first reflected image light sequentially passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches the partial reflection element BS on the second side S6 of the third lens E3, and then is reflected at the partial reflection element BS to form the second reflected image light. The second reflected image light 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 aperture STO and finally projects onto the user's eyes. For example, the light after two reflections of this visual system finally projects onto the user's eyes. A protective glass may also be provided between the image plane IMG and the fourth lens E4. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 2 shown.

[0079] Table 1 shows the basic parameter table of the visual system in Embodiment 1. Among them, the units of the radius of curvature and the thickness / distance are both millimeters (mm). The image light from the display screen passes through each element in the order from serial number 24 to serial number 1 and projects onto the user's eyes.

[0080]

[0081] Table 1

[0082] In this embodiment, any one of the object side and the image side of the first side S5 and the second side S6 of the third lens E3 and the second side S8 of the fourth lens E4 is an aspherical surface. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0083]

[0084] Among them, x is the distance sag from the vertex of the aspherical surface when the aspherical surface is along the optical axis direction at a position with a height of h; 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 2 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, S6, and S8 in Embodiment 1.

[0085]

[0086]

[0087] Table 2

[0088] Example 2

[0089] Refer to the following Figure 3 to describe the visual system according to Embodiment 2 of the present application.

[0090] As Figure 3 shown, the visual system may include a lens barrel P0, and an optical element group and a spacer element group assembled in the lens barrel P0.

[0091] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be disposed on the second side of the visual system, and a protective glass may also be disposed between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 3 it.

[0092] 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 high-order term coefficient table of the aspherical mirror surface is the same as Table 2.

[0093] The difference between this embodiment and Embodiment 1 lies in that the structural dimensions of the lens barrel and some spacer elements, and the distances of some spacer elements along the optical axis direction are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 1 are shown in Table 8 later.

[0094] Example 3

[0095] Refer to the following Figure 4 to describe the visual system according to Embodiment 3 of the present application.

[0096] As Figure 4 shown, the visual system may include a lens barrel P0, and an optical element group and a spacer element group assembled in the lens barrel P0.

[0097] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4, which are arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be disposed on the second side of the visual system, and a protective glass may also be disposed between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 4 shown.

[0098] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 1, that is, the basic parameter table of the visual system of this embodiment is the same as Table 1, and the high-order term coefficient table of the aspherical mirror surface is the same as Table 2.

[0099] The difference between this embodiment and Embodiment 1 lies in that the structural dimensions of the lens barrel and some spacer elements, the spacing of some spacer elements in the optical axis direction, and other parameters are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 1 are shown in Table 8 below.

[0100] Figure 5A The axial chromatic aberration curves of the visual systems of Embodiments 1, 2, and 3 are shown, which represent the deviation of the focusing points of light rays of different wavelengths after passing through the visual system. Figure 5B The astigmatism curves of the visual systems of Embodiments 1, 2, and 3 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 5C The distortion curves of the visual systems of Embodiments 1, 2, and 3 are shown, which represent the distortion magnitude values corresponding to different field angles. Figure 5D The modulation transfer function curves of the visual systems of Embodiments 1, 2, and 3 are shown. According to Figures 5A to 5D it can be known that the visual systems given in Embodiments 1, 2, and 3 can achieve good imaging quality.

[0101] Example 4

[0102] The following refers to Figure 6 to describe the visual system according to Embodiment 4 of the present application.

[0103] As Figure 6 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group assembled in the lens barrel P0.

[0104] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4, which are arranged in sequence along the optical axis from the first side to the second side. The aperture STO is disposed 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. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surface of each element is also referred to as the near-eye side surface, and the second side surface is also referred to as the near-screen side surface.

[0105] The first lens E1 has a positive optical power, its first side surface S1 is convex, and its second side surface S2 is concave. The second lens E2 has a positive optical power, its first side surface S3 is flat, and its second side surface S4 is convex. The third lens E3 has a negative optical power, its first side surface S5 is concave, and its second side surface S6 is convex. The fourth lens E4 has a positive optical power, its first side surface S7 is flat, and its second side surface S8 is convex. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the first side surface S3 of the second lens E2. The partial reflection element BS is attached to the second side surface S6 of the third lens E3. The second quarter-wave plate QWP2 and the polarizer LP are attached to the first side surface S7 of the fourth lens E4. It should be noted that the surfaces S1 to S8 are not shown in Figure 6 the figure.

[0106] In this example, an image plane IMG may be provided on the second side of the visual system, and a display screen may be provided on the image plane IMG. The light from the display screen sequentially passes through the fourth lens E4, the polarizer LP, the second quarter-wave plate QWP2, the third lens E3, the second lens E2, the first quarter-wave plate QWP1, reaches the reflective polarizing element RP, and then is reflected at the reflective polarizing element RP to form a first reflected image light. The first reflected image light sequentially passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches the partial reflection element BS on the second side surface S6 of the third lens E3, and then is reflected at the partial reflection element BS to form a second reflected image light. The second reflected image light 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 aperture STO and finally projects onto the user's eyes. For example, the light after two reflections of this visual system finally projects onto the user's eyes. A protective glass may also be provided between the image plane IMG and the fourth lens E4. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 6 the figure.

[0107] Table 3 shows the basic parameter table of the visual system in Embodiment 4, where the unit of the radius of curvature and the thickness / distance is millimeter (mm). The image light from the display screen passes through each element in the order of No. 24 to No. 1 and is projected onto the user's eyes.

[0108]

[0109]

[0110] Table 3

[0111] In this embodiment, any one of the object side and the image side of the first side S5 and the second side S6 of the third lens E3 and the second side S8 of the fourth lens E4 is an aspherical surface. Table 4 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0112] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S5 -4.3410E-01 1.1114E-01 -4.1613E-02 -2.5404E-04 3.3580E-03 1.8738E-03 4.9089E-04 0.0000E+00 0.0000E+00 S6 3.8184E-01 1.5502E-01 1.8114E-02 4.7055E-03 4.4412E-04 -3.0054E-05 1.8337E-06 0.0000E+00 0.0000E+00 S8 -1.2977E-01 2.3621E-02 -1.3190E-03 -1.4779E-04 1.3903E-04 -1.7295E-04 -7.2783E-05 0.0000E+00 0.0000E+00

[0113] Table 4

[0114] Example 5

[0115] The following refers to Figure 7 to describe the visual system according to Embodiment 5 of the present application.

[0116] As Figure 7 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group assembled in the lens barrel P0.

[0117] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be disposed on the second side of the visual system, and a protective glass may also be disposed between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 7 .

[0118] 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 high-order term coefficient table of the aspherical mirror surface is the same as Table 4.

[0119] The difference between this embodiment and Embodiment 4 lies in that the structural dimensions of the lens barrel and some spacer elements, the spacing of some spacer elements along the optical axis direction, and other parameters are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 4 are shown in Table 8 below.

[0120] Example 6

[0121] The following refers to Figure 8 Describe the visual system according to Embodiment 6 of the present application.

[0122] As Figure 8 shown, the visual system may include a lens barrel P0 and an optical element group and a spacer element group assembled in the lens barrel P0.

[0123] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be disposed on the second side of the visual system, and a protective glass may also be disposed between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 8 it.

[0124] 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 high-order term coefficient table of the aspherical mirror surface is the same as Table 4.

[0125] The difference between this embodiment and Embodiment 4 lies in that the structural dimensions of the lens barrel and some spacer elements, the spacing of some spacer elements along the optical axis direction, and other parameters are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 4 are shown in Table 8 below.

[0126] Figure 9A shows the axial chromatic aberration curves of the visual systems of Embodiments 4, 5, and 6, which represent the deviation of the convergence points of light rays of different wavelengths after passing through the visual system. Figure 9B shows the astigmatism curves of the visual systems of Embodiments 4, 5, and 6, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles.Figure 9C The distortion curves of the visual systems of Examples 4, 5, and 6 are shown, which represent the distortion magnitude values corresponding to different field angles of view. Figure 9D The modulation transfer function curves of the visual systems of Examples 4, 5, and 6 are shown. According to Figures 9A to 9D it can be seen that the visual systems given in Examples 4, 5, and 6 can achieve good imaging quality.

[0127] Example 7

[0128] The following refers to Figure 10 the visual system according to Embodiment 7 of the present application.

[0129] As Figure 10 shown, the visual system may include a barrel P0 and an optical element group and a spacer element group assembled in the barrel P0.

[0130] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. The aperture stop STO is disposed 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. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surface of each element is also referred to as the near-human-eye side surface, and the second side surface is also referred to as the near-screen side surface.

[0131] The first lens E1 has a positive optical power, its first side surface S1 is convex, and its second side surface S2 is concave. The second lens E2 has a positive optical power, its first side surface S3 is flat, and its second side surface S4 is convex. The third lens E3 has a negative optical power, its first side surface S5 is concave, and its second side surface S6 is convex. The fourth lens E4 has a positive optical power, its first side surface S7 is flat, and its second side surface S8 is convex. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the first side surface S3 of the second lens E2. The partial reflection element BS is attached to the second side surface S6 of the third lens E3. The second quarter-wave plate QWP2 and the polarizer LP are attached to the first side surface S7 of the fourth lens E4. It should be noted that the surfaces S1 to S8 are not shown in Figure 10 the figure.

[0132] In this example, an image surface IMG may be provided on the second side of the visual system, and a display screen may be provided on the image surface IMG. The light from the display screen sequentially passes through the fourth lens E4, the polarizer LP, the second quarter-wave plate QWP2, the third lens E3, the second lens E2, the first quarter-wave plate QWP1, reaches the reflective polarizing element RP, and then is reflected at the reflective polarizing element RP to form the first reflected image light. The first reflected image light sequentially passes through the first quarter-wave plate QWP1, the second lens E2, the third lens E3 and reaches the partial reflection element BS on the second side S6 of the third lens E3, and then is reflected at the partial reflection element BS to form the second reflected image light. The second reflected image light 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 aperture STO and finally projects onto the user's eyes. For example, the light after two reflections of this visual system finally projects onto the user's eyes. A protective glass may also be provided between the image surface IMG and the fourth lens E4. Among them, the aperture STO, the partial reflection element BS and the image surface IMG are not shown in Figure 10 shown.

[0133] Table 5 shows the basic parameter table of the visual system of Embodiment 7. Among them, the units of the radius of curvature and the thickness / distance are both millimeters (mm). The image light from the display screen passes through each element in the order of serial number 24 to serial number 1 and projects onto the user's eyes.

[0134]

[0135]

[0136] Table 5

[0137] In this embodiment, any one of the object side and the image side of the first side S5 and the second side S6 of the third lens E3 and the second side S8 of the fourth lens E4 is an aspherical surface. 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 S5, S6, S8 in Embodiment 7.

[0138] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S5 -1.5837E+00 -6.4837E-01 -6.2169E-01 -2.9333E-01 -1.0731E-01 -2.6438E-02 -2.9174E-03 0.0000E+00 0.0000E+00 S6 -1.7603E-01 -2.7204E-01 -2.8992E-01 -1.5499E-01 -6.0855E-02 -1.5901E-02 -2.0740E-03 0.0000E+00 0.0000E+00 S8 -3.4819E-02 2.7662E-03 4.0296E-03 -2.3324E-03 1.2051E-03 -4.8623E-04 7.0302E-05 0.0000E+00 0.0000E+00

[0139] Table 6

[0140] Example 8

[0141] The following refers to Figure 11Describe the visual system according to Embodiment 8 of the present application.

[0142] As Figure 11 shown, the visual system may include a lens barrel P0, and an optical element group and a spacer element group assembled within the lens barrel P0.

[0143] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4 arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be disposed on the second side of the visual system, and a protective glass may also be disposed between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 11 it.

[0144] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 7, that is, the basic parameter table of the visual system of this embodiment is the same as Table 5, and the high-order term coefficient table of the aspherical mirror surface is the same as Table 6.

[0145] The difference between this embodiment and Embodiment 7 lies in that the structural dimensions of the lens barrel and some spacer elements, the spacing of some spacer elements in the optical axis direction, and other parameters are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 7 are shown in Table 8 below.

[0146] Example 9

[0147] The following refers to Figure 12 Describe the visual system according to Embodiment 9 of the present application.

[0148] As Figure 12 shown, the visual system may include a lens barrel P0, and an optical element group and a spacer element group assembled within the lens barrel P0.

[0149] The optical element group includes 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 second quarter-wave plate QWP2, a polarizer LP, and a fourth lens E4, which are arranged in sequence along the optical axis from the first side to the second side. An aperture STO is disposed between the first side and the first lens E1. An image plane IMG may be provided on the second side of the visual system, and a protective glass may also be provided between the image plane IMG and the fourth lens E4. The spacer element group may include a first spacer element P1, a second spacer element P2, and a third spacer element P3. Among them, the aperture STO, the partial reflection element BS, and the image plane IMG are not shown in Figure 12 the figure.

[0150] 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 high-order term coefficient table of the aspherical mirror surface is the same as Table 6.

[0151] The difference between this embodiment and Embodiment 7 lies in that the structural dimensions of the lens barrel and some spacer elements, the spacing of some spacer elements along the optical axis direction, and other parameters are different. The numerical values of multiple parameters of the lens barrel and spacer elements included in the visual systems of this embodiment and Embodiment 7 are shown in Table 8 below.

[0152] Figure 13A The axial chromatic aberration curves of the visual systems of Embodiments 7, 8, and 9 are shown, which represent the deviation of the convergence points of light rays of different wavelengths after passing through the visual system. Figure 13B The astigmatism curves of the visual systems of Embodiments 7, 8, and 9 are shown, which represent the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 13C The distortion curves of the visual systems of Embodiments 7, 8, and 9 are shown, which represent the distortion magnitude values corresponding to different field angles. Figure 13D The modulation transfer function curves of the visual systems of Embodiments 7, 8, and 9 are shown. According to Figures 13A to 13D it can be known that the visual systems given in Embodiments 7, 8, and 9 can achieve good imaging quality.

[0153] Table 7 shows the values of the parameters f, f1, f2, f3, f4, fz1, fz2, and TD of each of Embodiments 1-9.

[0154] Example parameters 1 2 3 4 5 6 7 8 9 f (mm) 42.00 42.00 42.00 42.00 42.00 42.00 42.00 42.00 42.00 f1 (mm) 58.81 58.81 58.81 51.92 51.92 51.92 58.31 58.31 58.31 f2 (mm) 597.28 597.28 597.28 157.39 157.39 157.39 179.63 179.63 179.63 f3 (mm) -219.37 -219.37 -219.37 -105.99 -105.99 -105.99 -109.47 -109.47 -109.47 f4 (mm) 72.13 72.13 72.13 151.27 151.27 151.27 40.00 40.00 40.00 fz1 (mm) 597.28 597.28 597.28 157.39 157.39 157.39 179.63 179.63 179.63 fz2 (mm) 72.13 72.13 72.13 151.27 151.27 151.27 40.00 40.00 40.00 TD (mm) 25.39 25.39 25.39 25.39 25.39 25.39 25.39 25.39 25.39

[0155] Table 7

[0156] Table 8 shows the values of d1s, d1m, D1s, D1m, d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, d0s, d0m, D0s, D0m, EP01, CP1, EP12, CP2, EP23, CP3 and L parameters for each of the Examples 1-9. Among them, at least some of the above parameters can be measured according to Figure 1 the marking method shown, and the units of the parameters listed in Table 8 are all mm.

[0157]

[0158]

[0159] Table 8

[0160] Table 9 shows the values of the conditional expressions for each of the Examples 1-9.

[0161] Conditional formula / Example 1 2 3 4 5 6 7 8 9 T23 / CP2 1.11 1.10 1.20 1.11 1.11 1.10 1.15 1.13 1.08 (d2s + D2s) / fz1 0.10 0.10 0.10 0.38 0.36 0.36 0.33 0.32 0.31 (D1s + D1m) / R2 1.89 1.74 1.69 1.17 1.08 1.02 1.59 1.48 1.44 (d0s + D0s) / f1 1.45 1.35 1.30 1.65 1.54 1.46 1.41 1.32 1.27 CP3 / CP1 2.21 1.88 0.51 2.21 1.47 1.47 1.54 1.54 2.19 EP12 / (CTR + CTQ1 + CT2) 0.83 0.88 0.97 0.76 0.80 0.80 0.60 0.60 0.80 f / L 1.46 1.46 1.50 1.45 1.49 1.39 1.48 1.48 1.53 D2m / f3 -0.14 -0.13 -0.14 -0.29 -0.29 -0.26 -0.28 -0.27 -0.27 R6 / D3s -3.69 -4.05 -4.18 -4.65 -4.94 -5.41 -4.22 -4.45 -4.36 d0m / fz2 0.25 0.25 0.23 0.11 0.11 0.11 0.48 0.42 0.42 TD / EP01 3.13 3.17 3.14 3.01 3.20 2.56 3.06 2.89 3.23 EP23 / (CTQ2 + CTL + CT4) 3.42 3.37 3.43 4.08 4.00 4.04 3.36 3.32 2.87 D0m / D3m 1.12 1.18 0.84 1.12 1.10 0.99 1.13 1.19 1.08 d1s / CT1 5.59 5.50 5.69 4.54 4.66 4.59 4.90 5.06 4.93 R5 / d2m -2.81 -2.99 -3.07 -1.95 -2.08 -2.11 -1.86 -1.93 -1.82 d1m / T12 10.92 10.75 11.11 15.78 16.22 15.96 11.75 12.15 11.83 (d3s + d3m) / f4 0.42 0.46 0.56 0.19 0.20 0.19 0.73 0.73 0.78

[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. The optical device is equipped with the visual system described above.

[0164] The above description is only the preferred embodiments of this application and the description of the applied technical principles. Those skilled in the art should understand that the scope of the application involved in this 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 application concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in this application.

Claims

1. A visual system, characterized in that: include: An optical element group, comprising, in order from the first side to the second side along the optical axis, 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 second quarter wave plate, a polarizing plate, and a fourth lens with positive optical power; a spacer element group, comprising a second spacer element 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, in which the spacer element group and the optical element group are assembled; Wherein, the number of lenses with optical power in the visual system is four; Wherein, 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 spacing element along the optical axis direction satisfy: 1.08≤T23 / CP2<1.25; The inner diameter d2s of the first side surface of the second spacing element, the outer diameter D2s of the first side surface of the second spacing element and the combined focal length fz1 of the reflective polarizing element, the first quarter-wave plate and the second lens satisfy: 0.05<(d2s+D2s) / fz1<0.

4.

2. The visual system according to claim 1, characterized in that: An inner diameter d0s of the first side end surface of the lens barrel, an outer diameter D0s of the first side end surface of the lens barrel, and an effective focal length f1 of the first lens satisfy the following: 1.25<(d0s+D0s) / f1<1.

7.

3. The visual system according to claim 1, characterized in that: The total effective focal length f of the visual system and the distance L between the first side end surface of the lens barrel and the second side end surface of the lens barrel along the optical axis satisfy: 1.35 <f / L<1.55。 4. The visual system according to claim 1, characterized in that: The outer diameter D2m of the second side surface of the second spacing element and the effective focal length f3 of the third lens satisfy: -0.3 <D2m / f3<-0.1。 5. The visual system according to claim 1, characterized in that: The inner diameter d0m of the second side end surface of the lens barrel and the combined focal length fz2 of the second quarter wave plate, the polarizing plate and the fourth lens satisfy: 0.1 <d0m / fz2<0.5。 6. The visual system according to claim 1, characterized in that: 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: -3.1 <R5 / d2m<-1.8。 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 disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; An outer diameter D1s of the first side surface of the first spacer element, an outer diameter D1m of the second side surface of the first spacer element, and a curvature radius R2 of the second side surface of the first lens satisfy: 1.0<(D1s+D1m) / R2<1.

9.

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 disposed on the second side of the first lens and in contact with the second side of the first lens, and a third spacer element disposed on the second side of the third lens and in contact with the second side of the third lens; The maximum thickness CP1 of the first spacing element along the optical axis direction and the maximum thickness CP3 of the third spacing element along the optical axis direction satisfy: 0.5 <CP3 / CP1<2.25。 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 disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; The distance EP12 between the first spacing element and the second spacing element along the optical axis, 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, and the center thickness CT2 of the second lens on the optical axis satisfy: 0.55 <EP12 / (CTR+CTQ1+CT2)<1.0。 10. 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 disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The curvature radius R6 of the second side surface of the third lens and the outer diameter D3s of the first side surface of the third spacing element satisfy: -5.5 <R6 / D3s<-3.65。 11. 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 disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; The on-axis distance TD from the first side surface of the first lens to the second side surface of the fourth lens and the distance EP01 along the optical axis between the first side end surface of the lens barrel and the first spacing element satisfy: 2.55 <TD / EP01<3.25。 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 disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The distance EP23 between the second spacing element and the third spacing element along the optical axis, the center thickness CTQ2 of the second quarter wave plate on the optical axis, the center thickness CTL of the polarizer on the optical axis and the center thickness CT4 of the fourth lens on the optical axis satisfy: 2.85 <EP23 / (CTQ2+CTL+CT4)<4.1。 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 disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; The outer diameter D0m of the second side end surface of the lens barrel and the outer diameter D3m of the second side surface of the third spacing element satisfy: 0.8 <D0m / D3m<1.2。 14. 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 disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; The inner diameter d1s of the first side surface of the first spacing element and the center thickness CT1 of the first lens on the optical axis satisfy: 4.5 <d1s / CT1<5.7。 15. 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 disposed on the second side surface of the first lens and in contact with the second side surface of the first lens; An inner diameter d1m of the second side surface of the first spacer element and an axial distance T12 from the second side surface of the first lens to the first side surface of the second lens satisfy the following: 10.75≤d1m / T12<16.

25.

16. 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 disposed on the second side surface of the third lens and in contact with the second side surface of the third lens; An inner diameter d3s of the first side surface of the third spacing element, an inner diameter d3m of the second side surface of the third spacing element, and an effective focal length f4 of the fourth lens satisfy: 0.15<(d3s+d3m) / f4<0.

8.

17. 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 first side surface of the fourth lens is a plane, and the second side surface is a convex surface.

Images