VR optical system

Abstract

The invention provides a VR optical system, which sequentially comprises a first optical element group, a second optical element group and a third optical element group from human eyes to a display, and is characterized in that the first optical element group at least comprises a first lens; the second optical element group at least comprises a second lens; the third optical element group comprises a third lens, and the third lens has focal power; the first optical element group or the second optical element group further comprises a reflective polaroid and a quarter delay sheet; wherein the lenses are provided with side surfaces close to human eyes and side surfaces close to a display, and at least one surface of the first lens, the second lens and the third lens is provided with a partial reflection layer; the effective focal length FG1 of the first optical element group, the effective focal length FG2 of the second optical element group and the effective focal length group FG3 of the third optical element group meet the following conditions: 0 lt; fG1 / FG2 + FG3lt; 4.0, 0. According to the invention, the problem that miniaturization and high image quality cannot be considered at the same time in a VR optical system in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging equipment, and in particular to a VR optical system. Background Art

[0002] With the rise of AR and VR, VR optical devices have gradually entered the public eye, and consumers' expectations for VR optics have gradually increased, resulting in a gradual increase in the consumption of VR optical devices. Currently, VR optical devices are still under development, and there are still many areas that need to be improved, such as their size, weight, and imaging quality.

[0003] Normally, in order to improve image quality, the number of lenses in the optical lens will be increased, which can effectively balance various aberrations and help increase the imaging quality of the optical lens. As VR optical devices develop in the direction of miniaturization and lightweight, VR optical systems need to develop in the direction of miniaturization and lightweight. Increasing the number of lenses will increase the volume and weight of the VR optical system, and reducing the number of lenses will result in loss of image quality, making it difficult for the VR optical system to simultaneously meet the requirements of miniaturization and high imaging quality. In addition, the size of the lenses mounted in the VR optical system is small, which increases the difficulty of lens processing, resulting in lower design freedom of the lenses, making it difficult to improve the imaging quality of the VR optical system.

[0004] In other words, the VR optical system in the prior art has the problem of not being able to achieve both miniaturization and high image quality. Summary of the invention

[0005] The main purpose of the present invention is to provide a VR optical system to solve the problem that miniaturization and high image quality cannot be achieved at the same time in the VR optical system in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a VR optical system is provided, which includes a first optical element group, a second optical element group and a third optical element group in sequence from the human eye to the display, wherein the first optical element group includes at least a first lens; the second optical element group includes at least a second lens; the third optical element group includes a third lens, and the third lens has optical focal length; the first optical element group or the second optical element group also includes a reflective polarizer and a quarter retardation plate; wherein the lens has a side surface close to the human eye and a side surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflection layer; the effective focal length FG1 of the first optical element group, the effective focal length FG2 of the second optical element group and the effective focal length FG3 of the third optical element group satisfy the following: <FG1 / |FG2+FG3|<4.0。

[0007] Further, when the first optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the first lens is glued to the reflective polarizer near the side surface of the display.

[0008] Furthermore, when the second optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the second lens is glued to the quarter retardation plate on the side surface close to the human eye.

[0009] Furthermore, the center thickness CT2 of the second lens on the optical axis of the VR optical system and the center thickness CT3 of the third lens on the optical axis satisfy: 0.25 <CT2 / CT3<7.2。

[0010] Furthermore, the side surface of the third lens close to the display is convex.

[0011] Furthermore, the curvature radius R22 of the second lens surface close to the display side and the curvature radius R31 of the third lens surface close to the human eye side satisfy: 0.76 <R22 / R31<11.1。

[0012] Furthermore, the effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy the following relationship: 2.4 <FG1 / f<16.4。

[0013] Furthermore, the refractive index of the first lens, the second lens and the third lens is greater than 1.5 and less than 1.7.

[0014] Furthermore, the distance T12 between the side surface of the first lens close to the display and the side surface of the second lens close to the human eye on the optical axis of the VR optical system, and the distance T23 between the side surface of the second lens close to the display and the side surface of the third lens close to the human eye on the optical axis satisfy: 1.0 <T23 / T12<3.8。

[0015] Furthermore, the distance TD between the side surface of the first optical element group close to the human eye and the side surface of the third lens close to the display on the optical axis of the VR optical system and the center thickness CT1 of the first lens on the optical axis satisfy: 4.6 <TD / CT1<7.2。

[0016] Further, a curvature radius R11 of a surface of the first lens on the side close to the human eye and a curvature radius R22 of a surface of the second lens on the side close to the display satisfy: 0.6<|R11+R22| / (R11-R22)<5.8.

[0017] Further, a center thickness CT3 of the third lens on the optical axis of the VR optical system and a center thickness CTQ of the quarter retardation plate on the optical axis satisfy: 10≦CT3 / CTQ<61.4.

[0018] Further, the first optical element group has positive optical power.

[0019] According to another aspect of the present invention, a VR optical system is provided, which includes a first optical element group, a second optical element group and a third optical element group in sequence from the human eye to the display, wherein the first optical element group includes at least a first lens; the second optical element group includes at least a second lens; the third optical element group includes a third lens, and the third lens has optical power; the first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation film; wherein the lens has a side surface close to the human eye and a side surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflection layer; the effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy the following relationship: 2.4 <FG1 / f<16.4。

[0020] Further, when the first optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the first lens is glued to the reflective polarizer near the side surface of the display.

[0021] Furthermore, when the second optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the second lens is glued to the quarter retardation plate on the side surface close to the human eye.

[0022] Furthermore, the center thickness CT2 of the second lens on the optical axis of the VR optical system and the center thickness CT3 of the third lens on the optical axis satisfy: 0.25 <CT2 / CT3<7.2。

[0023] Furthermore, the side surface of the third lens close to the display is convex.

[0024] Furthermore, the curvature radius R22 of the second lens surface close to the display side and the curvature radius R31 of the third lens surface close to the human eye side satisfy: 0.76 <R22 / R31<11.1。

[0025] Furthermore, the refractive index of the first lens, the second lens and the third lens is greater than 1.5 and less than 1.7.

[0026] Furthermore, the distance T12 between the side surface of the first lens close to the display and the side surface of the second lens close to the human eye on the optical axis of the VR optical system, and the distance T23 between the side surface of the second lens close to the display and the side surface of the third lens close to the human eye on the optical axis satisfy: 1.0 <T23 / T12<3.8。

[0027] Furthermore, the distance TD between the side surface of the first optical element group close to the human eye and the side surface of the third lens close to the display on the optical axis of the VR optical system and the center thickness CT1 of the first lens on the optical axis satisfy: 4.6 <TD / CT1<7.2。

[0028] Further, a curvature radius R11 of a surface of the first lens on the side close to the human eye and a curvature radius R22 of a surface of the second lens on the side close to the display satisfy: 0.6<|R11+R22| / (R11-R22)<5.8.

[0029] Further, a center thickness CT3 of the third lens on the optical axis of the VR optical system and a center thickness CTQ of the quarter retardation plate on the optical axis satisfy: 10≦CT3 / CTQ<61.4.

[0030] Further, the first optical element group has positive optical power.

[0031] By applying the technical solution of the present invention, a VR optical system includes, from the human eye to the display, a first optical element group, a second optical element group and a third optical element group in sequence, wherein the first optical element group includes at least a first lens; the second optical element group includes at least a second lens; the third optical element group includes a third lens, and the third lens has optical focal length; the first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation film; wherein the lens has a side surface close to the human eye and a side surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflective layer; the effective focal length FG1 of the first optical element group, the effective focal length FG2 of the second optical element group and the effective focal length FG3 of the third optical element group satisfy the following: <FG1 / |FG2+FG3|<4.0。

[0032] By setting a reflective polarizer, a quarter retardation plate and a partial reflective layer in the VR optical system, the polarization principle is used to realize the folding of the light path, so as to increase the optical path while reducing the length of the VR optical system, which is conducive to achieving high image quality and miniaturization at the same time. The reflective polarizer and the quarter retardation plate are set in the first optical element group or the second optical element group, so that the folding position of the light path is close to the human eye side, the folding distance of the light path is increased, the optical path is effectively increased, and then the imaging quality of the VR optical system is increased, while the length of the VR optical system is shortened. At the same time, the focal lengths of the first optical element group, the second optical element group and the third optical element group are restricted, and the optical focal length of the system is reasonably allocated, which is conducive to improving the imaging quality of the VR optical system and achieving the coexistence of miniaturization and high image quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0034] Figure 1 A schematic diagram of a VR optical system according to Example 1 of the present invention is shown;

[0035] Figures 2 to 4 The axial chromatic aberration curve, the astigmatism curve and the distortion curve of Example 1 of the present invention are respectively shown;

[0036] Figure 5 A schematic diagram of a VR optical system according to Example 2 of the present invention is shown;

[0037] Figures 6 to 8 The axial chromatic aberration curve, astigmatism curve and distortion curve of Example 2 of the present invention are respectively shown;

[0038] Fig. 9 A schematic diagram of a VR optical system according to Example 3 of the present invention is shown;

[0039] Figures 10 to 12 The axial chromatic aberration curve, astigmatism curve and distortion curve of Example 3 of the present invention are respectively shown;

[0040] Fig.13 A schematic diagram of a VR optical system according to Example 4 of the present invention is shown;

[0041] Figures 14 to 16 The axial chromatic aberration curve, astigmatism curve and distortion curve of Example 4 of the present invention are respectively shown;

[0042] Fig.17 A schematic diagram of a VR optical system according to Example 5 of the present invention is shown;

[0043] Figures 18 to 20 The axial chromatic aberration curve, astigmatism curve and distortion curve of Example 5 of the present invention are respectively shown.

[0044] The above drawings include the following reference numerals:

[0045] STO, human eye; E1, first lens; PR, reflective polarizer; QWP, quarter retardation plate; E2, second lens; E3, third lens; IMG, image plane. DETAILED DESCRIPTION

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0048] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0049] It should be noted that in this specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teaching of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0050] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0051] In this article, the paraxial area refers to the area 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 area; 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 area. The surface of each lens close to the object side is called the object side surface of the lens, and the surface of each lens close to the image side is called the image side surface of the lens. The judgment of the surface shape in the paraxial area can be based on the judgment method of the general knowledge in this field, and the positive and negative R value (R refers to the radius of curvature of the paraxial area, usually refers to the R value on the lens database (lens data) in the optical software) is used to judge the convexity. For the surface close to the human eye side, when the R value is positive, it is judged as a convex surface, and when the R value is negative, it is judged as a concave surface; for the surface close to the display side, when the R value is positive, it is judged as a concave surface, and when the R value is negative, it is judged as a convex surface.

[0052] In order to solve the problem in the prior art that miniaturization and high image quality cannot be achieved at the same time in VR optical systems, the present invention provides a VR optical system.

[0053] Embodiment 1

[0054] like Figures 1 to 20As shown, the VR optical system includes a first optical element group, a second optical element group and a third optical element group in sequence from the human eye to the display, wherein the first optical element group includes at least a first lens; the second optical element group includes at least a second lens; the third optical element group includes a third lens, and the third lens has optical focal length; the first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation film; wherein the lens has a side surface close to the human eye and a side surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflective layer; the effective focal length FG1 of the first optical element group, the effective focal length FG2 of the second optical element group and the effective focal length FG3 of the third optical element group satisfy the following: <FG1 / |FG2+FG3|<4.0。

[0055] By setting a reflective polarizer, a quarter retardation plate and a partial reflective layer in the VR optical system, the polarization principle is used to realize the folding of the light path, so as to increase the optical path while reducing the length of the VR optical system, which is conducive to achieving high image quality and miniaturization at the same time. The reflective polarizer and the quarter retardation plate are set in the first optical element group or the second optical element group, so that the folding position of the light path is close to the human eye side, the folding distance of the light path is increased, the optical path is effectively increased, and then the imaging quality of the VR optical system is increased, while the length of the VR optical system is shortened. At the same time, the focal lengths of the first optical element group, the second optical element group and the third optical element group are restricted, and the optical focal length of the system is reasonably allocated, which is conducive to improving the imaging quality of the VR optical system and achieving the coexistence of miniaturization and high image quality.

[0056] Optionally, when the first optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the first lens is glued to the reflective polarizer near the display side surface. Gluing the first lens, the reflective polarizer and the quarter retardation plate together is conducive to reducing the length of the VR optical system. The reflective polarizer and the quarter retardation plate are the same shape as the first lens near the display side surface, which increases the degree of freedom of the curved surface and is conducive to increasing the imaging quality of the VR optical system.

[0057] Optionally, when the second optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the second lens is glued to the quarter retardation plate on the side surface close to the human eye. Gluing the second lens, the reflective polarizer and the quarter retardation plate together is conducive to reducing the length of the VR optical system. The reflective polarizer and the quarter retardation plate are the same shape as the side surface of the second lens close to the human eye, which increases the degree of freedom of the curved surface and is conducive to increasing the imaging quality of the VR optical system.

[0058] It should be noted that whether the reflective polarizer and the quarter-wave retarder are provided on the first lens or the second lens, the reflective polarizer is closer to the human eye than the quarter-wave retarder.

[0059] In this embodiment, the central thickness CT2 of the second lens on the optical axis of the VR optical system and the central thickness CT3 of the third lens on the optical axis satisfy: 0.25 < CT2 / CT3 < 7.2. By controlling the ratio of the central thicknesses of the second lens and the third lens within a reasonable range, the optical powers of the second lens and the third lens can be controlled, so that the aberration of the second lens compensates for the aberration of the third lens, thereby reducing the aberration of the VR optical system and improving the imaging quality.

[0060] In this embodiment, the surface of the third lens close to the display side is convex. By setting the surface of the third lens close to the display side to be convex, the light is converged by the surface of the third lens close to the display side, which is beneficial to reducing the screen size.

[0061] In this embodiment, the curvature radius R22 of the surface of the second lens close to the display side and the curvature radius R31 of the surface of the third lens close to the human eye side satisfy: 0.76 < R22 / R31 < 11.1. By controlling R22 / R31 within a reasonable range, it is beneficial to avoid interference between the second lens and the third lens, which is beneficial to the assembly stability of the second lens and the third lens, and ensures the assembly stability of the VR optical system.

[0062] In this embodiment, the effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy: 2.4 < FG1 / f < 16.4. By controlling FG1 / f within a reasonable range, it is beneficial to control the distribution of the optical power of the first lens in the optical system, thereby controlling the focal length of the first lens to compensate for the aberration generated by the second lens and the third lens, and improving the imaging quality of the VR optical system.

[0063] In this embodiment, the refractive indices of the first lens, the second lens, and the third lens are greater than 1.5 and less than 1.7. By controlling the refractive indices of the three lenses so that the refractive indices of the lenses are in the range of low refractive indices, it is beneficial to the selection of low-stress materials, thereby reducing the influence of the birefringence of the materials on the polarization of the VR optical system.

[0064] In this embodiment, the distance T12 between the surface of the first lens close to the display side and the surface of the second lens close to the human eye side on the optical axis of the VR optical system, and the distance T23 between the surface of the second lens close to the display side and the surface of the third lens close to the human eye side on the optical axis satisfy: 1.0 < T23 / T12 < 3.8. By controlling T23 / T12 within a reasonable range, the air gaps in the VR optical system are evenly distributed, which is conducive to the abutment between the lenses, avoids the formation of large step structures, and is beneficial to increasing the assembly stability.

[0065] In this embodiment, the distance TD between the surface of the first optical element group close to the human eye side and the surface of the third lens close to the display side on the optical axis of the VR optical system, and the central thickness CT1 of the first lens on the optical axis satisfy: 4.6 < TD / CT1 < 7.2. By controlling TD / CT1 within a reasonable range, the proportion of the central thickness of the first lens in the total length of the entire optical system is reasonably controlled, the structural strength of the first lens is ensured, and it is beneficial to the stable abutment of the first lens.

[0066] In this embodiment, the radius of curvature R11 of the surface of the first lens close to the human eye side and the radius of curvature R22 of the surface of the second lens close to the display side satisfy: 0.6 < |R11 + R22| / (R11 - R22) < 5.8. By controlling |R11 + R22| / (R11 - R22) within a reasonable range, it is beneficial to control the shapes of the first lens and the second lens, is beneficial to applying films on the first lens and the second lens, and at the same time is beneficial to reducing the reflection of light between the two lenses, thereby reducing the ghost image intensity of the VR optical system.

[0067] In this embodiment, the central thickness CT3 of the third lens on the optical axis of the VR optical system and the central thickness CTQ of the quarter-wave retarder on the optical axis satisfy: 10 ≤ CT3 / CTQ < 61.4. By controlling CT3 / CTQ within a reasonable range, it is beneficial to control the central thickness of the quarter-wave retarder, ensure the support strength of the quarter-wave retarder, and at the same time is beneficial to the attachment between the quarter-wave retarder and the lens and the reflective polarizer.

[0068] In this embodiment, the first optical element group has a positive optical power. Setting the first optical element group to have a positive optical power is conducive to the convergence of light, which is beneficial to reducing the effective sizes of the second lens and the third lens and is beneficial to the miniaturization of the VR optical system.

[0069] Embodiment 2

[0070] As Figures 1 to 20As shown, the VR optical system includes a first optical element group, a second optical element group and a third optical element group in sequence from the human eye to the display, wherein the first optical element group includes at least a first lens; the second optical element group includes at least a second lens; the third optical element group includes a third lens, and the third lens has optical power; the first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation film; wherein the lens has a side surface close to the human eye and a side surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflection layer; the effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy the following relationship: 2.4 <FG1 / f<16.4。

[0071] By setting a reflective polarizer, a quarter retardation plate and a partial reflective layer in the VR optical system, the polarization principle is used to realize the folding of the light path, so as to increase the optical path while reducing the length of the VR optical system, which is conducive to achieving high image quality and miniaturization at the same time. The reflective polarizer and the quarter retardation plate are set in the first optical element group or the second optical element group, so that the folding position of the light path is close to the human eye side, the folding distance of the light path is increased, the optical path is effectively increased, and then the imaging quality of the VR optical system is increased, while the length of the VR optical system is shortened. At the same time, controlling FG1 / f within a reasonable range is conducive to controlling the distribution of the optical power of the first lens in the optical system, thereby controlling the focal length of the first lens to compensate for the aberrations generated by the second lens and the third lens, and increasing the imaging quality of the VR optical system.

[0072] Optionally, when the first optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the first lens is glued to the reflective polarizer near the display side surface. Gluing the first lens, the reflective polarizer and the quarter retardation plate together is conducive to reducing the length of the VR optical system. The reflective polarizer and the quarter retardation plate are the same shape as the first lens near the display side surface, which increases the degree of freedom of the curved surface and is conducive to increasing the imaging quality of the VR optical system.

[0073] Optionally, when the second optical element group includes a reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the second lens is glued to the quarter retardation plate on the side surface close to the human eye. Gluing the second lens, the reflective polarizer and the quarter retardation plate together is conducive to reducing the length of the VR optical system. The reflective polarizer and the quarter retardation plate are the same shape as the side surface of the second lens close to the human eye, which increases the degree of freedom of the curved surface and is conducive to increasing the imaging quality of the VR optical system.

[0074] It should be noted that whether the reflective polarizer and the quarter-wave retarder are disposed on the first lens or the second lens, the reflective polarizer is closer to the human eye than the quarter-wave retarder.

[0075] In this embodiment, the center thickness CT2 of the second lens on the optical axis of the VR optical system and the center thickness CT3 of the third lens on the optical axis satisfy: 0.25 < CT2 / CT3 < 7.2. By controlling the ratio of the center thicknesses of the second lens and the third lens within a reasonable range, the optical powers of the second lens and the third lens can be controlled, so that the aberration of the second lens compensates for the aberration of the third lens, thereby reducing the aberration of the VR optical system and improving the imaging quality.

[0076] In this embodiment, the surface of the third lens close to the display side is convex. By setting the surface of the third lens close to the display side to be convex, the light is converged by the surface of the third lens close to the display side, which is beneficial to reducing the screen size.

[0077] In this embodiment, the radius of curvature R22 of the surface of the second lens close to the display side and the radius of curvature R31 of the surface of the third lens close to the human eye side satisfy: 0.76 < R22 / R31 < 11.1. By controlling R22 / R31 within a reasonable range, it is beneficial to avoid interference between the second lens and the third lens, which is beneficial to the assembly stability of the second lens and the third lens and ensures the assembly stability of the VR optical system.

[0078] In this embodiment, the refractive indices of the first lens, the second lens, and the third lens are greater than 1.5 and less than 1.7. By controlling the refractive indices of the three lenses to be within the range of low refractive indices, it is beneficial to the selection of low-stress materials, thereby reducing the influence of the birefringence of the material on the polarization of the VR optical system.

[0079] In this embodiment, the distance T12 on the optical axis between the surface of the first lens close to the display side and the surface of the second lens close to the human eye side, and the distance T23 on the optical axis between the surface of the second lens close to the display side and the surface of the third lens close to the human eye side satisfy: 1.0 < T23 / T12 < 3.8. By controlling T23 / T12 within a reasonable range, the air gaps in the VR optical system are evenly distributed, which is beneficial to the bearing between the lenses, avoiding the formation of a large step structure, and is beneficial to increasing the assembly stability.

[0080] In this embodiment, the distance TD on the optical axis of the VR optical system between the surface of the first optical element group close to the human eye side and the surface of the third lens close to the display side, and the central thickness CT1 of the first lens on the optical axis satisfy: 4.6 < TD / CT1 < 7.2. By controlling TD / CT1 within a reasonable range, reasonably controlling the proportion of the central thickness of the first lens in the total length of the entire optical system, ensuring the structural strength of the first lens, and facilitating the stable bearing of the first lens.

[0081] In this embodiment, the radius of curvature R11 of the surface of the first lens close to the human eye side and the radius of curvature R22 of the surface of the second lens close to the display side satisfy: 0.6 < |R11 + R22| / (R11 - R22) < 5.8. By controlling |R11 + R22| / (R11 - R22) within a reasonable range, it is beneficial to control the shapes of the first lens and the second lens, beneficial to applying films on the first lens and the second lens, and at the same time beneficial to reducing the reflection of light between the two lenses, thereby reducing the ghost image intensity of the VR optical system.

[0082] In this embodiment, the central thickness CT3 of the third lens on the optical axis of the VR optical system and the central thickness CTQ of the quarter-wave retarder on the optical axis satisfy: 10 ≤ CT3 / CTQ < 61.4. By controlling CT3 / CTQ within a reasonable range, it is beneficial to control the central thickness of the quarter-wave retarder, ensure the support strength of the quarter-wave retarder, and at the same time beneficial to the attachment between the quarter-wave retarder and the lens and the reflective polarizer.

[0083] In this embodiment, the first optical element group has a positive optical power. Setting the first optical element group to have a positive optical power is beneficial to the convergence of light, thereby beneficial to reducing the effective sizes of the second lens and the third lens, and beneficial to the miniaturization of the VR optical system.

[0084] The VR optical system in this application can adopt multiple lenses, such as the three lenses mentioned above. By reasonably distributing the optical power, surface shape, central thickness of each lens, and the axial distance between each lens, etc., the imaging quality of the VR optical system can be effectively improved, and the volume of the VR optical system can be reduced.

[0085] In this application, at least one of the mirror surfaces of each lens is an aspherical mirror surface. The characteristics of an aspherical lens are 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 radius of curvature 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.

[0086] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the VR optical system can be changed to obtain the various results and advantages described in this specification. For example, although three lenses are described as an example in the embodiment, the VR optical system is not limited to including three lenses. If necessary, the VR optical system may also include other numbers of lenses.

[0087] The following further describes examples of specific surface shapes and parameters of the VR optical system applicable to the above-mentioned embodiments with reference to the accompanying drawings.

[0088] It should be noted that any one of the following examples 1 to 5 is applicable to all embodiments of the present application.

[0089] Example 1

[0090] like Figures 1 to 4 As shown, the VR optical system of Example 1 of the present application is described. Figure 1 A schematic diagram of the VR optical system structure of Example 1 is shown.

[0091] like Figure 1 As shown, the VR optical system includes the human eye STO, the first lens E1, the reflective polarizer PR, the quarter retardation film QWP, the second lens E2, the third lens E3 and the image plane IMG in order from the human eye to the display. Among them, the image plane IMG can be considered as the display.

[0092] In this embodiment, the first optical element group includes a first lens E1, a reflective polarizer PR and a quarter retardation plate QWP.

[0093] The surface of the first lens close to the human eye is convex, and the surface of the first lens close to the display is flat. The surface of the second lens close to the human eye is convex, and the surface of the second lens close to the display is concave. The surface of the third lens close to the human eye is convex, and the surface of the third lens close to the display is convex. The surface of the third lens close to the display has a partial reflective layer.

[0094] Table 1 shows the basic structural parameter table of the VR optical system of Example 1, wherein the units of the radius of curvature, thickness / distance and focal length are all in millimeters (mm), the arrangement order of the surfaces is the order in which the light passes, and the refraction / reflection is the refraction or reflection effect of the surface on the light during this passage.

[0095]

[0096]

[0097] Table 1

[0098] In Example 1, the surface shape of the aspheric lens in the first lens E1 to the third lens E3 can be defined by but not limited to the following aspheric surface formula:

[0099]

[0100] Among them, x is the distance vector height from the vertex of the aspherical surface when the aspherical surface is at a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c=1 / R (that is, the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 below gives the high-order coefficients A4, A6, A8, and A10 that can be used for each aspherical mirror surface in Example 1.

[0101]

[0102] Table 2

[0103] Figure 2 The axial chromatic aberration curve of the VR optical system of Example 1 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the VR optical system. Figure 3 An astigmatism curve of the VR optical system of Example 1 is shown, which indicates meridional field curvature and sagittal field curvature. Figure 4 The distortion curve of the VR optical system of Example 1 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0104] according to Figures 2 to 4 It can be seen that the VR optical system given in Example 1 can achieve good imaging quality.

[0105] Example 2

[0106] like Figures 5 to 8 As shown, the VR optical system of Example 2 of the present application is described. Figure 5 FIG. 2 is a schematic diagram of the VR optical system structure of Example 2. For the sake of brevity, some descriptions similar to Example 2 will be omitted.

[0107] like Figure 5 As shown, the VR optical system includes the human eye STO, the first lens E1, the reflective polarizer PR, the quarter retardation plate QWP, the second lens E2, the third lens E3 and the image plane IMG in sequence from the human eye to the display.

[0108] In this embodiment, the first optical element group includes a first lens E1, a reflective polarizer PR and a quarter retardation plate QWP.

[0109] The surface of the first lens close to the human eye is convex, and the surface of the first lens close to the display is flat. The surface of the second lens close to the human eye is convex, and the surface of the second lens close to the display is convex. The surface of the third lens close to the human eye is concave, and the surface of the third lens close to the display is convex. The surface of the third lens close to the display has a partial reflective layer.

[0110] Table 3 shows a basic structural parameter table of the VR optical system of Example 2, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0111]

[0112] Table 3

[0113] Table 4 gives the higher-order coefficients that can be used for each aspherical mirror surface in Example 5.

[0114]

[0115] Table 4

[0116] Figure 6 The axial chromatic aberration curve of the VR optical system of Example 2 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the VR optical system. Figure 7 An astigmatism curve of the VR optical system of Example 2 is shown, which indicates the meridional field curvature and the sagittal field curvature. Figure 8 The distortion curve of the VR optical system of Example 2 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0117] according to Figures 6 to 8 It can be seen that the VR optical system given in Example 2 can achieve good imaging quality.

[0118] Example 3

[0119] like Figures 9 to 12 As shown, the VR optical system of Example 3 of the present application is described. Fig. 9 FIG. 4 is a schematic diagram of the VR optical system structure of Example 3. For the sake of brevity, some descriptions similar to Example 3 will be omitted.

[0120] like Fig. 9 As shown, the VR optical system includes the human eye STO, the first lens E1, the reflective polarizer PR, the quarter retardation plate QWP, the second lens E2, the third lens E3 and the image plane IMG in sequence from the human eye to the display.

[0121] In this embodiment, the second optical element group includes a reflective polarizer PR, a quarter retardation plate QWP and a second lens E2.

[0122] The surface of the first lens close to the human eye is concave, and the surface of the first lens close to the display is convex. The surface of the second lens close to the human eye is flat, and the surface of the second lens close to the display is convex. The surface of the third lens close to the human eye is concave, and the surface of the third lens close to the display is convex. The surface of the third lens close to the display has a partial reflective layer.

[0123] Table 5 shows a basic structural parameter table of the VR optical system of Example 3, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0124]

[0125] Table 5

[0126] Table 6 gives the high-order coefficients that can be used for each aspherical mirror surface in Example 2.

[0127]

[0128] Table 6

[0129] Fig.10 The axial chromatic aberration curve of the VR optical system of Example 3 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the VR optical system. Fig.11 An astigmatism curve of the VR optical system of Example 3 is shown, which indicates the meridional field curvature and the sagittal field curvature. Fig.12 The distortion curve of the VR optical system of Example 3 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0130] according to Figures 10 to 12 It can be seen that the VR optical system given in Example 3 can achieve good imaging quality.

[0131] Example 4

[0132] like Figures 13 to 16 As shown, the VR optical system of Example 4 of the present application is described. Fig.13 FIG. 4 is a schematic diagram of the VR optical system structure of Example 4. For the sake of brevity, some descriptions similar to Example 4 will be omitted.

[0133] like Fig.13 As shown, the VR optical system includes the human eye STO, the first lens E1, the reflective polarizer PR, the quarter retardation plate QWP, the second lens E2, the third lens E3 and the image plane IMG in sequence from the human eye to the display.

[0134] In this embodiment, the second optical element group includes a reflective polarizer PR, a quarter retardation plate QWP and a second lens E2.

[0135] The surface of the first lens close to the human eye is concave, and the surface of the first lens close to the display is convex. The surface of the second lens close to the human eye is flat, and the surface of the second lens close to the display is concave. The surface of the third lens close to the human eye is convex, and the surface of the third lens close to the display is convex. The surface of the third lens close to the display has a partial reflective layer.

[0136] Table 7 shows the basic structural parameter table of the VR optical system of Example 4, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0137]

[0138]

[0139] Table 7

[0140] Table 8 gives the higher-order coefficients that can be used for each aspherical mirror surface in Example 2.

[0141]

[0142] Table 8

[0143] Fig.14 The axial chromatic aberration curve of the VR optical system of Example 4 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the VR optical system. Fig.15 An astigmatism curve of the VR optical system of Example 4 is shown, which indicates the meridional field curvature and the sagittal field curvature. Fig.16 The distortion curve of the VR optical system of Example 4 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0144] according to Figures 14 to 16 It can be seen that the VR optical system given in Example 4 can achieve good imaging quality.

[0145] Example 5

[0146] like Figures 17 to 20 As shown, the VR optical system of Example 5 of the present application is described. Fig.17 FIG. 5 is a schematic diagram of the structure of the VR optical system of Example 5. For the sake of brevity, some descriptions similar to Example 5 will be omitted.

[0147] like Fig.17 As shown, the VR optical system includes the human eye STO, the first lens E1, the reflective polarizer PR, the quarter retardation plate QWP, the second lens E2, the third lens E3 and the image plane IMG in sequence from the human eye to the display.

[0148] In this embodiment, the second optical element group includes a reflective polarizer PR, a quarter retardation plate QWP and a second lens E2.

[0149] The surface of the first lens close to the human eye is concave, and the surface of the first lens close to the display is convex. The surface of the second lens close to the human eye is flat, and the surface of the second lens close to the display is convex. The surface of the third lens close to the human eye is concave, and the surface of the third lens close to the display is convex. The surface of the third lens close to the display has a partial reflective layer.

[0150] Table 9 shows the basic structural parameter table of the VR optical system of Example 5, wherein the units of the radius of curvature, thickness / distance and focal length are all millimeters (mm).

[0151]

[0152] Table 9

[0153] Table 10 gives the higher-order coefficients that can be used for each aspherical mirror surface in Example 3.

[0154]

[0155] Table 10

[0156] Fig.18 The axial chromatic aberration curve of the VR optical system of Example 5 is shown, which indicates the deviation of the focal point of light of different wavelengths after passing through the VR optical system. Fig.19 An astigmatism curve of the VR optical system of Example 5 is shown, which indicates meridional field curvature and sagittal field curvature. Fig. 20 The distortion curve of the VR optical system of Example 5 is shown, which represents the distortion magnitude values ​​corresponding to different field angles.

[0157] according to Figures 18 to 20 It can be seen that the VR optical system given in Example 5 can achieve good imaging quality.

[0158] Example 1 and Example 2 illustrate the direction of the light emitted from the image plane IMG. The light emitted from the image plane IMG passes through the third lens surface close to the display side (surface 18), the third lens surface close to the human eye side (surface 17), the second lens surface close to the display side (surface 16), and the second lens surface close to the human eye side (surface 15) in sequence, and then is incident on the quarter retardation plate surface close to the display side (surface 14). The quarter retardation plate converts the light into a light of a first polarization state. The light of the first polarization state is incident on the reflective polarizer surface close to the display side (surface 13, which is also the surface of the quarter retardation plate close to the human eye side) and is reflected to form a first reflected light. The first reflected light is incident on the quarter retardation plate surface close to the display side (surface 12). The quarter retardation plate QWP converts the first reflected light into a light of a second polarization state. The light of the second polarization state passes through the second lens surface close to the human eye side (surface 11), The second lens is close to the display side surface (surface 10) and the third lens is close to the human eye side surface (surface 9), and then reflected by the third lens close to the display side surface (surface 8, and partially reflected by the third lens close to the display side surface) to form a second reflected light. The second reflected light passes through the third lens close to the human eye side surface (surface 7), the second lens close to the display side surface (surface 6), and the second lens close to the human eye side surface (surface 5) in sequence, and then is incident on the quarter retardation plate close to the display side surface (surface 4). The quarter retardation plate QWP converts the second magnetic reflected light into light of the third polarization state. The light of the third polarization state is incident on the surface (surface 3) of the reflective polarizer close to the display side, and is transmitted by the surface (surface 3) of the reflective polarizer close to the display side. The transmitted light passes through the surface (surface 2) of the first lens close to the display side and the surface (surface 1) of the first lens close to the human eye side in sequence, and then is incident on the human eye STO.

[0159] The directions of the light in Examples 3 to 5 are similar to those in Examples 1 and 2, and will not be described in detail here.

[0160] It should be noted that, in the process of the light in the first polarization state being converted into the light in the third polarization state, it passes through two quarter-retardation plates, thereby making the polarization direction of the light in the first polarization state perpendicular to the polarization direction of the light in the third polarization state. Therefore, the reflective polarizing element reflects the light in the first polarization state and transmits the light in the third polarization state.

[0161] In summary, Examples 1 to 5 satisfy the relationships shown in Table 6 respectively.

[0162] Expression / Example Example 1 Example 2 Example 3 Example 4 Example 5 FG1 / (FG2+FG3) 1.526 3.963 0.692 0.704 0.006 CT2 / CT3 0.2504 5.695 7.160 0.308 0.437 R22 / R31 1.238 1.095 0.771 0.864 11.030 FG1 / f 9.454 16.377 5.105 2.413 2.407 T23 / T12 1.047 1.109 1.336 3.740 2.480 TD / CT1 7.133 7.164 6.856 4.733 4.686 |R11+R22| / (R11-R22) 5.746 0.647 1.235 0.737 1.310 CT3 / CTQ 52.500 10.000 10.000 61.380 57.750

[0163] Table 6

[0164] Table 7 gives some parameters of the VR optical systems of Examples 1 to 5.

[0165]

[0166]

[0167] Table 7

[0168] The present application also provides an imaging device, whose electronic photosensitive element can be a photosensitive coupled device (CCD) or a complementary metal oxide semiconductor element (CMOS). The imaging device can be an independent imaging device such as a digital camera, or an imaging module integrated in a mobile electronic device such as a mobile phone. The imaging device is equipped with the VR optical system described above.

[0169] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0170] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0171] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0172] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A VR optical system, characterized in that: From the human eye to the display, it includes a first optical element group, a second optical element group and a third optical element group in sequence, wherein: The first optical element group includes at least a first lens; The second optical element group includes at least a second lens; The third optical element group includes a third lens, and the third lens has optical power; The first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation plate; The lens has a surface close to the human eye and a surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflective layer; The effective focal length FG1 of the first optical element group, the effective focal length FG2 of the second optical element group and the effective focal length group FG3 of the third optical element group satisfy the following: <FG1 / |FG2+FG3|<4.0。 2. The VR optical system according to claim 1, characterized in that: When the first optical element group includes the reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the first lens is glued to the reflective polarizer near the side surface of the display.

3. The VR optical system according to claim 1, characterized in that: When the second optical element group includes the reflective polarizer and a quarter retardation plate, the reflective polarizer is glued to the quarter retardation plate, and the second lens is glued to the quarter retardation plate on the side surface close to the human eye.

4. The VR optical system according to claim 1, characterized in that: The center thickness CT2 of the second lens on the optical axis of the VR optical system and the center thickness CT3 of the third lens on the optical axis satisfy: 0.25 <CT2 / CT3<7.2。 5. The VR optical system according to claim 1, characterized in that: The side surface of the third lens close to the display is convex.

6. The VR optical system according to claim 1, characterized in that: The curvature radius R22 of the second lens surface close to the display side and the curvature radius R31 of the third lens surface close to the human eye side satisfy: 0.76 <R22 / R31<11.1。 7. The VR optical system according to claim 1, characterized in that: The effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy the following relationship: 2.4 <FG1 / f<16.4。 8. The VR optical system according to claim 1, characterized in that: The refractive indexes of the first lens, the second lens and the third lens are greater than 1.5 and less than 1.

7.

9. The VR optical system according to any one of claims 1 to 8, characterized in that: The distance T12 between the side surface of the first lens close to the display and the side surface of the second lens close to the human eye on the optical axis of the VR optical system, and the distance T23 between the side surface of the second lens close to the display and the side surface of the third lens close to the human eye on the optical axis satisfy: 1.0 <T23 / T12<3.8。 10. A VR optical system, characterized in that: From the human eye to the display, it includes a first optical element group, a second optical element group and a third optical element group in sequence, wherein: The first optical element group includes at least a first lens; The second optical element group includes at least a second lens; The third optical element group includes a third lens, and the third lens has optical power; The first optical element group or the second optical element group further includes a reflective polarizer and a quarter retardation plate; The lens has a surface close to the human eye and a surface close to the display, and at least one surface of the first lens, the second lens and the third lens has a partial reflective layer; The effective focal length FG1 of the first optical element group and the effective focal length f of the VR optical system satisfy the following relationship: 2.4 <FG1 / f<16.4。

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