Visual system

Abstract

The utility model discloses a visual system which comprises a lens cone, an optical element group and a bearing element group, wherein the optical element group and the bearing 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 positive 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 polarizer; the bearing element group comprises a second bearing element; the second bearing 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 outer diameter D2s of the first side surface of the second bearing element and the outer diameter D2m of the second side surface of the second bearing element meet the following conditions: 1.0 lt; d < 2s > / D < 2mlt >; 1.2; 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 bearing element meet the following conditions: 1.0 lt; t23 / CP2lt, T23 / CP2lt; and 1.2.

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. 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] 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 a visual system, which includes a lens barrel and an optical element group and a supporting element group placed in the lens barrel. The optical element group includes a first lens with positive focal length, a reflective polarizing element, a first quarter-wave plate, a second lens with positive focal length, a third lens with negative focal length, a partial reflecting element, a fourth lens with positive focal length, a second quarter-wave plate and a polarizer arranged in sequence from the first side to the second side along the optical axis. The supporting element group includes a second supporting element, which is placed on the second side of the second lens and contacts the second side of the second lens. Wherein, the outer diameter D2s of the first side of the second supporting element and the outer diameter D2m of the second side of the second supporting element satisfy: 1.0 <D2s / D2m<1.2;第二透镜的第二侧面至第三透镜的第一侧面的轴上距离T23与第二承靠元件的最大厚度CP2满足:1.0<T23 / CP2<1.2。

[0006] 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 entrance pupil diameter EPD of the visual system satisfy the following relationship: 1.2 <d0s / EPD<1.4。

[0007] According to an exemplary embodiment of the present application, the inner diameter d2s of the first side surface of the second bearing element and the central thickness CT2 of the second lens on the optical axis satisfy: 11.0 < d2s / CT2 ≤ 16.2.

[0008] According to an exemplary embodiment of the present application, 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 length L of the lens barrel in the direction of the optical axis satisfy: 1.0 < TD / L < 1.2.

[0009] According to an exemplary embodiment of the present application, the effective focal length f4 of the fourth lens, the inner diameter d0m of the second end surface of the lens barrel and the outer diameter D0m of the second end surface of the lens barrel satisfy: 0.9 < f4 / (d0m + D0m) < 1.8.

[0010] According to an exemplary embodiment of the present application, the effective focal length f3 of the third lens and the inner diameter d2m of the second side surface of the second bearing element satisfy: -0.25 < d2m / f3 < -0.1.

[0011] According to an exemplary embodiment of the present application, the total effective focal length f of the visual system and the outer diameter D0s of the first end surface of the lens barrel satisfy: 1.2 < f / D0s < 1.3.

[0012] According to an exemplary embodiment of the present application, the effective focal length f1 of the first lens and the inner diameter d0s of the first end surface of the lens barrel satisfy: 2.0 < f1 / d0s < 4.1.

[0013] According to an exemplary embodiment of the present application, the effective focal length f2 of the second lens and the outer diameter D2s of the first side surface of the second bearing element satisfy: 0.05 < D2s / f2 < 0.25.

[0014] According to an exemplary embodiment of the present application, the bearing element group further includes a third bearing element, and the third bearing element is placed on the second side surface of the third lens and in contact with the second side surface of the third lens. Among them, the interval distance EP23 between the second bearing element and the third bearing element along the optical axis and the central thickness CT3 of the third lens on the optical axis satisfy: 1.2 < EP23 / CT3 < 2.1.

[0015] According to an exemplary embodiment of the present application, the bearing element group further includes a third bearing element, and the third bearing element is placed on the second side surface of the third lens and in contact with the second side surface of the third lens. Among them, the sum ∑CT of the central thicknesses of all the lenses from the first lens to the fourth lens on the optical axis, the maximum thickness CP2 of the second bearing element and the maximum thickness CP3 of the third bearing element satisfy: 0.7 ≤ ∑CT / (CP2 + CP3) ≤ 2.3.

[0016] According to an exemplary embodiment of the present application, the bearing element group further includes a third bearing element, which is placed on the second side of the third lens and in contact with the second side of the third lens. Wherein, the radius of curvature R6 of the second side of the third lens and the inner diameter d3s of the first side of the third bearing element satisfy: -6.1 < R6 / d3s < -3.4.

[0017] According to an exemplary embodiment of the present application, the bearing element group further includes a third bearing element, which is placed on the second side of the third lens and in contact with the second side of the third lens. Wherein, the radius of curvature R7 of the first side of the fourth lens and the inner diameter d3m of the second side of the third bearing element satisfy: 0.4 < d3m / R7 < 1.3.

[0018] According to an exemplary embodiment of the present application, the bearing element group further includes a third bearing element, which is placed on the second side of the third lens and in contact with the second side of the third lens. Wherein, the combined focal length fz2 of the third lens, the fourth lens, the second quarter-wave plate and the polarizer, the outer diameter D3s of the first side of the third bearing element and the outer diameter D3m of the second side of the third bearing element satisfy: 0.8 < fz2 / (D3s + D3m) ≤ 2.6.

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

[0020] The visual system provided by the present application uses four lenses, and reasonably configuring the optical power of the four lenses is beneficial to improving the imaging quality of the visual system; and by cooperating with restricting the ratio of the outer diameters of the first side and the second side of the second bearing element and the ratio of the axial distance from the second side of the second lens to the first side of the third lens to the maximum thickness of the second bearing element, it is possible to make the second bearing element have a sufficient bearing area, thereby ensuring that the second bearing element has good supporting ability, and can also limit the external dimensions of the visual system, ensuring that the visual system and its whole machine equipment have smaller external dimensions. At the same time, while ensuring that the second bearing element has good machinability and high structural strength, it is beneficial to the miniaturization of the visual system and avoids the problems of excessive thickness of the visual system and its whole machine equipment and poor experience effect caused by the excessive thickness of the second bearing element. Description of the Drawings

[0021] Other features, objects and advantages of the present 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 annotation of the visual system according to the present application;

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

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

[0025] Figure 4 Shows a schematic structural diagram of the 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 (MTF) curve of the visual system according to Embodiment 1, 2 or 3 of the present application;

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

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

[0029] Figure 8 Shows a schematic structural diagram of the 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 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 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 are respectively shown. Detailed implementation manners

[0035] To better understand the present application, more detailed descriptions will be made on various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the 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, and third 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 accompanying drawings, for the sake of convenience 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 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 (such as the human eye side) is called the first side surface of the lens, and the surface of each lens closest to the second side (such as the display screen side) is called the second side surface of the lens.

[0039] It should also be understood that the terms "comprise", "comprising", "have", "containing", and / or "containing" when used in this specification indicate the presence of the stated features, elements, and / or components, but do not exclude 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". And 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) shall 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) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and shall 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 this application and the features in the embodiments may be combined with each other. The following will detail this application with reference to the drawings and in conjunction with the embodiments.

[0042] The features, principles, and other aspects of this 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 this 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 reflecting element, a fourth lens, a second quarter-wave plate, and a polarizer 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 focal power. The second lens may have a positive focal power. The third lens may have a negative focal power. The fourth lens may have a positive focal power. Reasonably configuring the focal 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 planar, 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.

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

[0049] In an exemplary embodiment, the first quarter-wave plate may be disposed on the first side 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. Circularly polarized light may include right-handed circularly polarized light or left-handed circularly polarized light. Linearly polarized light may include S linearly polarized light or P linearly polarized light.

[0050] In an exemplary embodiment, a reflective polarizing element may be disposed on a first side surface of a first quarter-wave plate. The reflective polarizing element is configured 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, a first side surface of a second lens may be a plane. 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, a partial reflection element may be disposed on a second side surface of a 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 and reflected multiple times, effectively reducing the body length of the visual system.

[0053] In an exemplary embodiment, a second quarter-wave plate may be disposed on a second side surface of a fourth lens. A polarizer may be disposed on a second side surface of the second quarter-wave plate. The polarizer is configured to convert natural light emitted from a display screen on the second side into linearly polarized light, and the second quarter-wave plate is configured to convert the linearly polarized light from the polarizer 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 polarizer, the natural light emitted from the display screen can be converted into circularly polarized light, thereby reducing the influence of material stress of the components between the display screen and the polarizer and improving the contrast of the visual system.

[0054] In an exemplary embodiment, a second side surface of the fourth lens may be a plane. The second quarter-wave plate and the polarizer are bonded and attached to the second side surface of the fourth lens. By combining the second quarter-wave plate and the polarizer 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 enhanced.

[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 polarizer, 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., and is finally projected onto the eyes of the user on the first side after multiple refractions and reflections.

[0056] In an exemplary embodiment, the first side can be the human-eye side, and the second side can 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 second quarter-wave plate) can be referred to as the near-human-eye side surfaces, and the second side surfaces can be referred to as the near-screen side surfaces.

[0057] In an exemplary embodiment, an image plane can be provided on the second side of the visual system. A display screen can be provided on the image plane. The image light from the display screen can sequentially pass through a polarizer, 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 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 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 aperture and is finally projected into the user's eyes. The visual system provided in this application folds the required optical path through 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 can further include a support element group. The support element group can include one or more of a first support element, a second support element, and a third support element. The first support element can be placed on the second side surface of the first lens and at least partially contact the second side surface of the first lens. The second support element can be placed on the second side surface of the second lens and at least partially contact the second side surface of the second lens. The third support element can be placed on the second side surface of the third lens and at least partially contact the second side surface of the third lens. Reasonable use of the support elements can effectively avoid the risk of stray light and reduce the interference to the image quality, thereby improving the imaging quality of the visual system.

[0059] In an exemplary embodiment, the visual system can further include a lens barrel. The optical element group and the support element group can be placed inside the lens barrel. The lens barrel can include a first side end face, a second side end face, an outer ring face and an inner ring face, wherein the end face of the lens barrel closest to the first side is the first side end face of the lens barrel, and the end face of the lens barrel closest to the second side is the second side end face of the lens barrel; in the direction perpendicular to the optical axis, the surface of the lens barrel farthest from the optical axis is the outer ring face, and the surface of the lens barrel closest to the optical axis is the inner ring face.

[0060] In an exemplary embodiment, the outer diameter D2s of the first side surface of the second bearing element and the outer diameter D2m of the second side surface of the second bearing element may satisfy: 1.0 < D2s / D2m < 1.2; 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 bearing element may satisfy: 1.0 < T23 / CP2 < 1.2. By controlling the ratio of the outer diameters of the first and second side surfaces of the second bearing element and 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 bearing element, the outer diameters of the first and second side surfaces of the second bearing element can be constrained within a certain range, so that the second bearing element has a sufficient bearing area, thus ensuring that the second bearing element has good supporting ability, and can also limit the external dimensions of the visual system to ensure that the visual system and its entire equipment have smaller external dimensions; at the same time, while ensuring that the second bearing element has good machinability and high structural strength, it is beneficial for the visual system to be miniaturized, avoiding the problems of excessive thickness of the visual system and its entire equipment and poor experience effect caused by the excessive thickness of the second bearing element.

[0061] In an exemplary embodiment, the inner diameter d0s of the first side end surface of the lens barrel and the entrance pupil diameter EPD of the visual system may satisfy: 1.2 < d0s / EPD < 1.4. By reasonably configuring the ratio of the inner diameter of the first side end surface of the lens barrel to the entrance pupil diameter of the visual system and making this ratio greater than 1.2, it can be ensured that the inner diameter of the first side end surface of the lens barrel is greater than the entrance pupil diameter of the visual system, and within a certain assembly eccentricity error, a sufficient number of light rays can be ensured to be incident on the visual system; at the same time, making this ratio less than 1.4 can reduce the number of stray light rays incident on the visual system and improve the imaging effect of the visual system.

[0062] In an exemplary embodiment, the inner diameter d2s of the first side surface of the second bearing element and the central thickness CT2 of the second lens on the optical axis may satisfy: 11.0 < d2s / CT2 ≤ 16.2. By reasonably configuring the ratio of the inner diameter of the first side surface of the second bearing element to the central thickness of the second lens on the optical axis, the inner diameter of the first side surface of the second bearing element and the central thickness of the second lens can be respectively constrained within a certain range, ensuring that the second bearing element and the second lens have good machinability, and enabling the second bearing element to effectively block excess light rays and reduce the stray light risk of the visual system.

[0063] In an exemplary embodiment, 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 length L of the lens barrel in the direction of the optical axis may satisfy: 1.0 < TD / L < 1.2. By reasonably configuring the ratio of the on-axis distance from the first side surface of the first lens to the second side surface of the fourth lens to the length of the lens barrel in the direction of the optical axis and making this ratio greater than 1, it can be ensured that the total length of the lens barrel is less than the on-axis distance from the first side surface of the first lens to the second side surface of the fourth lens, achieving an extreme compression of the total length of the lens barrel, thereby reducing the total length of the visual system and its entire equipment; at the same time, making this ratio less than 1.2 can ensure that the distance of the lens exceeding the first side end face or the second side end face of the lens barrel is appropriate, reducing the area of the first lens and the fourth lens exposed outside the lens barrel and reducing the risk of the first lens and the fourth lens being scratched during assembly and use.

[0064] In an exemplary embodiment, the effective focal length f4 of the fourth lens, the inner diameter d0m of the second side end face of the lens barrel, and the outer diameter D0m of the second side end face of the lens barrel may satisfy: 0.9 < f4 / (d0m + D0m) < 1.8. By reasonably configuring the ratio of the effective focal length of the fourth lens to the sum of the inner and outer diameters of the second side end face of the lens barrel, the effective focal length of the fourth lens can be made positive to ensure that the fourth lens converges light; at the same time, the inner diameter and outer diameter of the second side end face of the lens barrel can be constrained within an appropriate range to ensure good processability of the lens barrel and improve the structural strength of the lens barrel.

[0065] In an exemplary embodiment, the effective focal length f3 of the third lens and the inner diameter d2m of the second side surface of the second bearing element may satisfy: -0.25 < d2m / f3 < -0.1. By reasonably configuring the ratio of the inner diameter of the second side surface of the second bearing element to the effective focal length of the third lens, the effective focal length of the third lens can be made negative to ensure that the third lens diverges light; at the same time, the inner diameter of the second side surface of the second bearing element can be constrained within an appropriate range to ensure good processability of the second bearing element and enable the second bearing element to effectively block excess light, reducing the stray light risk of the visual system.

[0066] In an exemplary embodiment, the total effective focal length f of the visual system and the outer diameter D0s of the first side end face of the lens barrel may satisfy: 1.2 < f / D0s < 1.3. By reasonably configuring the ratio of the total effective focal length of the visual system to the outer diameter of the first side end face of the lens barrel, the outer diameter of the first side end face of the lens barrel can be constrained within a certain range, improving the processability of the lens barrel.

[0067] In an exemplary embodiment, the ratio of the effective focal length f1 of the first lens to the inner diameter d0s of the first side end face of the lens barrel may satisfy: 2.0 < f1 / d0s < 4.1. Reasonably configuring the ratio of the effective focal length of the first lens to the inner diameter of the first side end face of the lens barrel can make the effective focal length of the first lens positive, ensuring that the first lens converges light; at the same time, the inner diameter of the first side end face of the lens barrel can be restricted within an appropriate range, ensuring good processability of the lens barrel, and reducing the amount of stray light incident into the visual system, thereby improving the imaging effect of the visual system.

[0068] In an exemplary embodiment, the ratio of the effective focal length f2 of the second lens to the outer diameter D2s of the first side face of the second supporting element may satisfy: 0.05 < D2s / f2 < 0.25. Reasonably configuring the ratio of the outer diameter of the first side face of the second supporting element to the effective focal length of the second lens can make the effective focal length of the second lens positive, ensuring that the second lens converges light; at the same time, the outer diameter of the first side face of the second supporting element can be restricted within an appropriate range, ensuring good processability of the second supporting element and improving the structural strength of the second supporting element.

[0069] In an exemplary embodiment, the distance EP23 between the second supporting element and the third supporting element along the optical axis and the central thickness CT3 of the third lens on the optical axis may satisfy: 1.2 < EP23 / CT3 < 2.1. Reasonably configuring the ratio of the distance between the second supporting element and the third supporting element along the optical axis to the central thickness of the third lens on the optical axis can respectively restrict the edge thickness and the central thickness of the third lens, and restrict the thickness ratio between the edge and the center of the third lens within an appropriate range, thereby improving the processability of the third lens.

[0070] In an exemplary embodiment, the sum ∑CT of the central thicknesses of all the lenses from the first lens to the fourth lens on the optical axis, the maximum thickness CP2 of the second supporting element, and the maximum thickness CP3 of the third supporting element may satisfy: 0.7 ≤ ∑CT / (CP2 + CP3) ≤ 2.3. By controlling the above conditional expression, the thicknesses of the second supporting element and the third supporting element can be reasonably allocated, making the second supporting element and the third supporting element have high structural strength and good supporting ability; at the same time, the total length of the visual system can be restricted, avoiding the problems of excessive total length of the visual system and its entire equipment and poor experience effect caused by excessive thicknesses of the second supporting element and the third supporting element.

[0071] In an exemplary embodiment, the ratio of the radius of curvature R6 of the second side surface of the third lens to the inner diameter d3s of the first side surface of the third bearing element may satisfy: -6.1 < R6 / d3s < -3.4. By reasonably configuring the ratio of the radius of curvature of the second side surface of the third lens to the inner diameter of the first side surface of the third bearing element, the radius of curvature of the second side surface of the third lens can be made negative, ensuring that the second side surface of the third lens converges light; at the same time, the inner diameter of the first side surface of the third bearing element can be constrained within an appropriate range, ensuring that the third bearing element has good processability, and enabling the third bearing element to effectively block excess light, reducing the stray light risk of the visual system.

[0072] In an exemplary embodiment, the ratio of the radius of curvature R7 of the first side surface of the fourth lens to the inner diameter d3m of the second side surface of the third bearing element may satisfy: 0.4 < d3m / R7 < 1.3. By reasonably configuring the ratio of the inner diameter of the second side surface of the third bearing element to the radius of curvature of the first side surface of the fourth lens, the radius of curvature of the first side surface of the fourth lens can be made positive, ensuring that the first side surface of the fourth lens converges light; at the same time, the inner diameter of the second side surface of the third bearing element can be constrained within an appropriate range, ensuring that the third bearing element has good processability, and enabling the third bearing element to effectively block excess light, reducing the stray light risk of the visual system.

[0073] In an exemplary embodiment, the combined focal length fz2 of the third lens, the fourth lens, the second quarter-wave plate, and the polarizer, the outer diameter D3s of the first side surface of the third bearing element, and the outer diameter D3m of the second side surface of the third bearing element may satisfy: 0.8 < fz2 / (D3s + D3m) ≤ 2.6. By controlling the above conditional expression, the outer diameters of the first side surface and the second side surface of the third bearing element can be constrained within a reasonable range, enabling the third bearing element to have sufficient bearing area, thereby ensuring that the third bearing element has good structural strength and support ability; at the same time, the external dimensions of the visual system can be restricted, ensuring that the visual system and its entire equipment have smaller external dimensions.

[0074] The visual system according to the above embodiment of the present application may employ multiple lenses, such as the four lenses described above. By reasonably allocating the parameters of the second quarter-wave plate, the polarizer, each lens, the lens barrel, and each bearing 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, can well meet the usage requirements of various portable electronic products in the projection scenario, and the center of gravity of the visual system and the electronic device including the visual system moves backward, improving the user's wearing experience.

[0075] In an embodiment of the present application, at least one of the surfaces of each lens among the first lens to the fourth lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature continuously changes 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 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.

[0076] 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.

[0077] The second aspect of the present application provides such a visual system, which may include a lens barrel and an optical element group disposed in the lens barrel. The optical element group may include 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 fourth lens with a positive optical power, a second quarter-wave plate, and a polarizer arranged in sequence along the optical axis from the first side to the second side.

[0078] The inner diameter d0s of the first side end face of the lens barrel and the entrance pupil diameter EPD of the visual system may satisfy: 1.2 < d0s / EPD < 1.4. The visual system provided by the present application uses four lenses, and reasonably configuring the optical powers of the four lenses is beneficial to improving the imaging quality of the visual system. Moreover, by cooperating to limit the ratio of the inner diameter of the first side end face of the lens barrel to the entrance pupil diameter of the visual system, making this ratio greater than 1.2 can ensure that the inner diameter of the first side end face of the lens barrel is greater than the entrance pupil diameter of the visual system, and within a certain assembly eccentricity error, ensure that a sufficient number of light rays are incident on the visual system; at the same time, it can also make this ratio less than 1.4, reducing the number of stray light incident on the visual system and improving the imaging effect of the visual system.

[0079] The third aspect of the present application provides such a visual system, which may include a lens barrel, an optical element group, and a supporting element group disposed in the lens barrel. The optical element group may include 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 fourth lens with a positive optical power, a second quarter-wave plate, and a polarizer arranged in sequence along the optical axis from the first side to the second side. The supporting element group may include a third supporting element, and the third supporting element is disposed on the second side face of the third lens and in contact with the second side face of the third lens.

[0080] The radius of curvature R6 of the second side surface of the third lens and the inner diameter d3s of the first side surface of the third supporting element may satisfy: -6.1 < R6 / d3s < -3.4; the radius of curvature R7 of the first side surface of the fourth lens and the inner diameter d3m of the second side surface of the third supporting element may satisfy: 0.4 < d3m / R7 < 1.3. The visual system provided by the present application uses four lenses, and reasonably configuring the optical power of the four lenses is beneficial to improving the imaging quality of the visual system. Moreover, by cooperating with restricting the ratio of the radius of curvature of the second side surface of the third lens to the inner diameter of the first side surface of the third supporting element and the ratio of the inner diameter of the second side surface of the third supporting element to the radius of curvature of the first side surface of the fourth lens, it can be made that the radius of curvature of the second side surface of the third lens is negative and the radius of curvature of the first side surface of the fourth lens is positive, ensuring that the second side surface of the third lens and the first side surface of the fourth lens converge light rays; at the same time, the inner diameters of the first side surface and the second side surface of the third supporting element can also be constrained within an appropriate range, ensuring that the third supporting element has good processability and enabling the third supporting element to effectively block excess light rays and reduce the stray light risk of the visual system.

[0081] The following further describes specific embodiments of the visual system applicable to the above embodiments with reference to the accompanying drawings.

[0082] Example 1

[0083] The following refers to Figure 2 Describe the visual system according to Embodiment 1 of the present application.

[0084] As Figure 2 shown, the visual system may include a lens barrel P0 and an optical element group and a supporting element group disposed in the lens barrel P0.

[0085] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer 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 supporting element group may include a second supporting element P2 and a third supporting element P3. The first side surface of each element (for example, the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the second supporting element P2, and the third supporting element P3) is referred to as the side surface close to the human eye, and the second side surface is referred to as the side surface close to the screen.

[0086] The first lens E1 has a positive optical power. Its side S1 close to the human eye is convex, and its side S2 close to the screen is concave. The second lens E2 has a positive optical power. Its side S3 close to the human eye is flat, and its side S4 close to the screen is convex. The third lens E3 has a negative optical power. Its side S5 close to the human eye is concave, and its side S6 close to the screen is convex. The fourth lens E4 has a positive optical power. Its side S7 close to the human eye is convex, and its side S8 close to the screen is flat. The reflective polarizing element RP and the first quarter-wave plate QWP1 are attached to the side S3 of the second lens E2 close to the human eye. The partial reflection element BS is attached to the side S6 of the third lens E3 close to the screen. The second quarter-wave plate QWP2 and the polarizer LP are attached to the side S8 of the fourth lens E4 close to the screen.

[0087] 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. The image light from the image plane IMG sequentially passes through the polarizer 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, where the first reflection occurs. 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 S6 of the third lens E3 close to the screen, where the second reflection occurs. 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 aperture stop and finally projects into the user's eyes. For example, the light after two reflections of the visual system finally projects into the user's eyes. A protective glass (not shown) may also be provided between the image plane IMG and the polarizer LP.

[0088] Table 1 shows the basic parameter table of the visual system of 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 from No. 23 to No. 1 and finally projects into the human eyes.

[0089]

[0090]

[0091] Table 1

[0092] In this embodiment, the side S5 and the side S6 of the third lens E3 close to the human eye and the side S7 of the fourth lens E4 close to the human eye are all aspherical surfaces. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0093]

[0094] Among them, x is the sagitta, which is the distance from the vertex of the aspheric surface to the position along the optical axis at a height of h; c is the paraxial curvature of the aspheric 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 aspheric surface. Table 2 gives the high-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0095] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S5 -4.6221E-01 8.8946E-02 -5.5206E-02 -1.3412E-02 -5.1629E-03 -1.5918E-03 -3.8536E-04 0.0000E+00 0.0000E+00 S6 2.6838E-01 1.6185E-01 5.1195E-02 2.7031E-02 9.7489E-03 2.4221E-03 2.6929E-04 0.0000E+00 0.0000E+00 S7 1.1280E-01 -9.6967E-03 3.3226E-04 -1.9499E-04 -1.4313E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0096] Table 2

[0097] Example 2

[0098] The following refers to Figure 3 to describe the visual system according to Embodiment 2 of the present application.

[0099] As Figure 3 shown, the visual system may include a lens barrel P0 and an optical element group and a supporting element group disposed in the lens barrel P0.

[0100] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer 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 supporting element group may include a second supporting element P2 and a third supporting element P3.

[0101] 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 supporting element group are different.

[0102] Example 3

[0103] The following refers to Figure 4 to describe the visual system according to Embodiment 3 of the present application.

[0104] As Figure 4 shown, the visual system may include a lens barrel P0 and an optical element group and a supporting element group disposed in the lens barrel P0.

[0105] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer LP arranged in sequence along the optical axis from the first side to the second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The support element group may include a second support element P2 and a third support element P3.

[0106] 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 support element group are different.

[0107] 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 convergence 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 5C The 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. 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 seen that the visual systems given in Embodiment 1, 2 or 3 can achieve good imaging quality.

[0108] Example 4

[0109] The following refers to Figure 6 Describe the visual system according to Embodiment 4 of the present application.

[0110] As Figure 6 shown, the visual system may include a lens barrel P0 and an optical element group and a support element group disposed within the lens barrel P0.

[0111] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer LP arranged in sequence along the optical axis from the first side to the second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The support element group may include a second support element P2 and a third support element P3. The first side surfaces of the respective elements (e.g., the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the second support element P2, and the third support 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.

[0112] 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 polarizer LP are attached to the near-screen side surface S8 of the fourth lens E4.

[0113] 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, for example. After the image light from the image plane IMG sequentially passes through the polarizer 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 near-screen side surface 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 aperture 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 polarizer LP.

[0114] Table 3 shows the basic parameter table of the visual system of Example 4, where the unit of the radius of curvature and the thickness / distance is millimeter (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.

[0115]

[0116] Table 3

[0117] In this embodiment, 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 .

[0118] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S5 -3.2408E-01 -2.2957E-01 -3.3271E-01 -2.0137E-01 -1.1801E-01 -5.3238E-02 -9.1168E-03 0.0000E+00 0.0000E+00 S6 5.2280E-02 4.6291E-03 -4.7358E-02 -2.6200E-02 -1.7878E-02 -1.0288E-02 -1.8757E-03 0.0000E+00 0.0000E+00 S7 1.7461E-01 -2.2494E-03 -1.6176E-03 1.6677E-04 -3.0210E-04 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

[0119] Table 4

[0120] Example 5

[0121] The following refers to Figure 7 to describe the visual system according to Embodiment 5 of the present application.

[0122] As Figure 7 shown, the visual system may include a lens barrel P0 and an optical element group and a support element group disposed in the lens barrel P0.

[0123] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer LP arranged in sequence along the optical axis from the first side to the second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The support element group may include a second support element P2 and a third support element P3.

[0124] The structure of the optical element group in this embodiment is the same as that of the optical element group in Example 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 Example 4 is that the structural dimensions of at least some elements in the lens barrel P0 and the support element group are different.

[0125] Example 6

[0126] The following refers toFigure 8 Describe the visual system according to Embodiment 6 of the present application.

[0127] As Figure 8 shown, the visual system may include a lens barrel P0, and an optical element group and a supporting element group disposed within the lens barrel P0.

[0128] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer 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 supporting element group may include a second supporting element P2 and a third supporting element P3.

[0129] 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 aspheric 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 supporting element group are different.

[0130] 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 9B Shows the astigmatism curve of the visual system of Embodiment 4, 5 or 6, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 9C Shows the distortion curve of the visual system of Embodiment 4, 5 or 6, which represents the distortion magnitude values corresponding to different field angles. Figure 9D Shows the modulation transfer function curve of the visual system of Embodiment 4, 5 or 6. According to Figures 9A to 9D it can be known that the visual systems given in Embodiment 4, 5 or 6 can achieve good imaging quality.

[0131] Example 7

[0132] The following refers to Figure 10 Describe the visual system according to Embodiment 7 of the present application.

[0133] As Figure 10 shown, the visual system may include a lens barrel P0, and an optical element group and a supporting element group disposed within the lens barrel P0.

[0134] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer LP, which are arranged in sequence along the optical axis from the first side to the second side. An aperture STO (not shown) may also be provided between the first side and the first lens E1. The support element group may include a first support element P1, a second support element P2, and a third support element P3. The first side surfaces of each element (e.g., the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, the second support element P2, and the third support 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.

[0135] 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 convex. The fourth lens E4 has a positive optical power. Its side surface S7 close to the human eye is convex, 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 polarizer LP are attached to the side surface S8 close to the screen of the fourth lens E4.

[0136] 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 polarizer 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 reflected for the first time 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 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, the first lens E1 to the aperture 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 polarizer LP.

[0137] Table 5 shows the basic parameters of the visual system of Example 7, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface IMG passes through the components in the order of sequence number 23 to sequence number 1 and is finally projected into the human eye.

[0138]

[0139] Table 5

[0140] In this embodiment, the side surface S4 near the screen of the second lens E2, the side surface S5 near the screen and the side surface S6 near the screen of the third lens E3, and the side surface S7 near the eye of the fourth lens E4 are all aspherical surfaces. Table 6 shows the high-order coefficients A4, A6, A8, A9, A10, A11, A12, A13, A14, A15, A16, A17, A18, A19, A20, A21, A22, A23, A24, A25, A26, A27, A28, A29, A30, A31, A32, A33, A34, A35, A36, A37, A38, A39, A40, A41, A42, A43, A44, A45, A46, A47, A48, A49, A50, A51, 10 , A 12 , A 14 , A 16 , A 18 and A 20 .

[0141] 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

[0142] Table 6

[0143] Example 8

[0144] The following reference Figure 11 Describe the visual system according to Example 8 of the present application.

[0145] like Figure 11 As shown, the visual system may include a lens barrel P0 and an optical element group and a supporting element group placed in the lens barrel P0.

[0146] 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 (not shown), a fourth lens E4, a second quarter wave plate QWP2 and a polarizer LP arranged in sequence from the first side to the second side along the optical axis. A stop STO (not shown) may also be provided between the first side and the first lens E1. The supporting element group may include a first supporting element P1, a second supporting element P2 and a third supporting element P3.

[0147] 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 aspheric coefficient table is the same as Table 6. The difference between this embodiment and Embodiment 7 is that the structure size of at least part of the elements in the lens barrel P0 and the supporting element group is different.

[0148] Example 9

[0149] Refer to the following Figure 12 to describe the visual system according to Embodiment 9 of the present application.

[0150] As Figure 12 shown, the visual system may include a lens barrel P0, an optical element group, and a support element group disposed within the lens barrel P0.

[0151] 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 (not shown), a fourth lens E4, a second quarter-wave plate QWP2, and a polarizer LP arranged in sequence along the optical axis from the first side to the second side. An aperture stop STO (not shown) may also be provided between the first side and the first lens E1. The support element group may include a first support element P1, a second support element P2, and a third support element P3.

[0152] 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 aspheric 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 elements in the lens barrel P0 and the support element group are different.

[0153] 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 13B shows the astigmatism curve of the visual system of Embodiment 7, 8, or 9, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 13C shows the distortion curve of the visual system of Embodiment 7, 8, or 9, which represents the distortion magnitude values corresponding to different field angles. Figure 13D shows the modulation transfer function curve of the visual system of Embodiment 7, 8, or 9. According to Figures 13A to 13D it can be known that the visual system given in Embodiment 7, 8, or 9 can achieve good imaging quality.

[0154] Table 7 gives the values of parameters such as f, f1, f2, f3, f4, EPD, fz2, TD, and ∑CT for each of Embodiments 1-9. Among them, the units of f, f1, f2, f3, f4, EPD, fz2, TD, and ∑CT in Table 7 are all millimeters (mm).

[0155] Parameter / Example 1 2 3 4 5 6 7 8 9 f 42.00 42.00 42.00 42.00 42.00 42.00 41.50 41.50 41.50 f1 60.68 60.68 60.68 120.50 120.50 120.50 85.14 85.14 85.14 f2 143.65 143.65 143.65 500.00 500.00 500.00 191.39 191.39 191.39 f3 -99.13 -99.13 -99.13 -207.14 -207.14 -207.14 -114.15 -114.15 -114.15 f4 61.68 61.68 61.68 39.51 39.51 39.51 32.78 32.78 32.78 EPD 23.00 23.00 23.00 23.00 23.00 23.00 23.00 23.00 23.00 fz2 140.51 140.51 140.51 48.18 48.18 48.18 45.10 45.10 45.10 TD 24.74 24.74 24.74 25.74 25.74 25.74 24.83 24.83 24.83 ∑CT 15.23 15.23 15.23 8.91 8.91 8.91 9.80 9.80 9.80

[0156] Table 7

[0157] Table 8 shows the values of parameters such as d2s, d2m, D2s, D2m, d3s, d3m, D3s, D3m, d0s, d0m, D0s, D0m, CP2, EP23, CP3, and L for each of Examples 1-9. Among them, 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 millimeters (mm).

[0158] Parameter / Example 1 2 3 4 5 6 7 8 9 d2s 27.3049 27.3049 27.3049 26.7078 26.7078 26.7078 27.3433 27.3433 27.3433 d2m 23.3539 23.3539 23.3539 25.5553 25.5553 25.7553 23.6286 24.0754 24.0754 D2s 28.3653 28.3653 28.3653 27.7681 27.7681 27.8681 28.7433 28.7433 28.7433 D2m 25.6449 25.6449 25.6449 27.0630 27.0630 27.2630 26.5371 26.9839 26.9839 d3s 22.3369 22.3369 22.3369 25.7050 25.7050 25.6054 23.1158 23.1158 23.6366 d3m 22.3369 22.3369 22.3369 25.7050 25.7050 25.6054 23.1158 23.1158 23.6366 D3s 27.0719 27.0719 27.0719 27.5463 27.5463 27.5463 27.8509 27.8509 27.8509 D3m 27.0719 27.0719 27.0719 27.5463 27.5463 27.5463 27.8509 27.8509 27.8509 d0s 30.1771 30.1771 30.1771 29.7381 29.7381 29.7381 31.0868 31.0868 31.0868 d0m 15.5937 15.5937 15.5937 16.5851 16.5851 16.5851 16.0236 16.0236 16.0236 D0s 33.1973 33.1973 33.1973 32.7584 32.7584 32.7584 34.1071 34.1071 34.1071 D0m 19.0200 19.0200 19.0200 20.0114 20.0114 20.0114 20.1157 20.1157 20.1157 CP2 6.8355 6.6355 6.5355 12.6466 12.5466 12.4466 11.3981 11.5483 11.5483 EP23 7.6497 7.8497 7.9497 2.1186 2.2186 2.3186 2.6302 2.4800 2.3760 CP3 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 L 22.3558 22.3558 22.3558 24.4073 24.4073 24.4073 21.9959 21.9959 21.7959

[0159] Table 8

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

[0161] Condition / Example 1 2 3 4 5 6 7 8 9 D2s / D2m 1.11 1.11 1.11 1.03 1.03 1.02 1.08 1.07 1.07 T23 / CP2 1.03 1.06 1.08 1.11 1.11 1.12 1.07 1.06 1.06 d0s / EPD 1.31 1.31 1.31 1.29 1.29 1.29 1.35 1.35 1.35 d2s / CT2 11.05 11.05 11.05 16.20 16.20 16.20 12.78 12.78 12.78 EP23 / CT3 1.21 1.24 1.25 1.63 1.71 1.78 2.02 1.91 1.83 TD / L 1.11 1.11 1.11 1.05 1.05 1.05 1.13 1.13 1.14 ∑CT / (CP2 + CP3) 2.20 2.26 2.30 0.70 0.70 0.71 0.85 0.84 0.84 R6 / d3s -6.01 -6.01 -6.01 -3.47 -3.47 -3.48 -4.27 -4.27 -4.17 d3m / R7 0.42 0.42 0.42 1.24 1.24 1.24 0.82 0.82 0.84 f4 / (d0m + D0m) 1.78 1.78 1.78 1.08 1.08 1.08 0.91 0.91 0.91 d2m / f3 -0.24 -0.24 -0.24 -0.12 -0.12 -0.12 -0.21 -0.21 -0.21 f / D0s 1.27 1.27 1.27 1.28 1.28 1.28 1.22 1.22 1.22 fz2 / (D3s + D3m) 2.60 2.60 2.60 0.87 0.87 0.87 0.81 0.81 0.81 f1 / d0s 2.01 2.01 2.01 4.05 4.05 4.05 2.74 2.74 2.74 D2s / f2 0.20 0.20 0.20 0.06 0.06 0.06 0.15 0.15 0.15

[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 explanation of the applied technical principles. Those skilled in the art should understand that the scope of the utility model 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 inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in this application.

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 partially reflecting element, a fourth lens with positive optical power, a second quarter wave plate and a polarizer, which are arranged in sequence from a first side to a second side along an optical axis; A supporting element group, comprising a second supporting element, wherein the second supporting element is disposed on a second side surface of the second lens and contacts the second side surface of the second lens; as well as A lens barrel, wherein the optical element group and the supporting element group are placed in the lens barrel; Wherein, the number of lenses with optical power in the visual system is four; The outer diameter D2s of the first side surface of the second supporting element and the outer diameter D2m of the second side surface of the second supporting element satisfy: 1.0 <D2s / D2m≤1.11; 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 supporting element satisfy: 1.0 <T23 / CP2≤1.12。 2. 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 entrance pupil diameter EPD of the visual system satisfy the following: 1.29≤d0s / EPD<1.

4.

3. The visual system according to claim 1, characterized in that: The inner diameter d2s of the first side surface of the second supporting element and the center thickness CT2 of the second lens on the optical axis satisfy: 11.0 <d2s / CT2≤16.2。 4. The visual system according to claim 1, characterized in that: The axial distance TD from the first side surface of the first lens to the second side surface of the fourth lens and the length L of the lens barrel along the direction of the optical axis satisfy: 1.0 <TD / L≤1.14。 5. The visual system according to claim 1, characterized in that: The effective focal length f4 of the fourth lens, the inner diameter d0m of the second side end surface of the lens barrel and the outer diameter D0m of the second side end surface of the lens barrel satisfy: 0.9 <f4 / (d0m+D0m)<1.8。 6. The visual system according to claim 1, characterized in that: The effective focal length f3 of the third lens and the inner diameter d2m of the second side surface of the second supporting element satisfy: -0.25 <d2m / f3<-0.1。 7. The visual system according to claim 1, characterized in that: The total effective focal length f of the visual system and the outer diameter D0s of the first side end surface of the lens barrel satisfy: 1.2 <f / D0s<1.3。 8. The visual system according to claim 1, characterized in that: The effective focal length f1 of the first lens and the inner diameter d0s of the first side end surface of the lens barrel satisfy: 2.0 <f1 / d0s<4.1。 9. The visual system according to claim 1, characterized in that: The effective focal length f2 of the second lens and the outer diameter D2s of the first side surface of the second supporting element satisfy: 0.05 <D2s / f2<0.25。 10. The visual system according to any one of claims 1 to 9, characterized in that: The supporting element group further includes a third supporting element, and the third supporting element is disposed on the second side surface of the third lens and contacts the second side surface of the third lens; The spacing distance EP23 between the second supporting element and the third supporting element along the optical axis and the center thickness CT3 of the third lens on the optical axis satisfy: 1.2 <EP23 / CT3≤2.02。 11. The visual system according to any one of claims 1 to 9, characterized in that: The supporting element group further includes a third supporting element, and the third supporting element is disposed on the second side surface of the third lens and contacts the second side surface of the third lens; The sum of the center thicknesses ΣCT of all lenses from the first lens to the fourth lens on the optical axis, the maximum thickness CP2 of the second supporting element and the maximum thickness CP3 of the third supporting element satisfy: 0.7≤ΣCT / (CP2+CP3)≤2.

3.

12. The visual system according to any one of claims 1 to 9, characterized in that: The supporting element group further includes a third supporting element, and the third supporting element is disposed on the second side surface of the third lens and contacts the second side surface of the third lens; The curvature radius R6 of the second side surface of the third lens and the inner diameter d3s of the first side surface of the third supporting element satisfy: -6.01≤R6 / d3s≤-3.

47.

13. The visual system according to any one of claims 1 to 9, characterized in that: The supporting element group further includes a third supporting element, and the third supporting element is disposed on the second side surface of the third lens and contacts the second side surface of the third lens; The curvature radius R7 of the first side surface of the fourth lens and the inner diameter d3m of the second side surface of the third supporting element satisfy: 0.4 <d3m / R7≤1.24。 14. The visual system according to any one of claims 1 to 9, characterized in that: The supporting element group further includes a third supporting element, and the third supporting element is disposed on the second side surface of the third lens and contacts 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 polarizer, the outer diameter D3s of the first side surface of the third supporting element and the outer diameter D3m of the second side surface of the third supporting element satisfy the following conditions: 0.8 <fz2 / (D3s+D3m)≤2.6。 15. The visual system according to any one of claims 1 to 9, 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 a second side surface of the fourth lens; and The polarizer 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 9, 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, and the second side surface is a convex surface; The first side surface of the fourth lens is a convex surface, and the second side surface is a flat surface.

Images