Visual optical system

Abstract

The application discloses a visual optical system, which comprises a first lens group and a second lens group from the side far from the screen to the side close to the screen along the optical axis, the first lens group comprises a first lens, a reflective polarizing element and a quarter-wave plate; the second lens group comprises a second lens and a partial reflection layer; wherein the side far from the screen of the first lens or the side far from the screen of the second lens is a Fresnel surface; the visual optical system further comprises a lens barrel and a first supporting part arranged on the side close to the screen of the first lens, the first supporting part is at least partially in contact with the side close to the screen of the first lens or the side far from the screen of the second lens; the first lens group, the second lens group and the first supporting part are all contained in the lens barrel, wherein the inner diameters of the side far from the screen and the side close to the screen of the first supporting part are both greater than 50 mm, and the inner diameter d1m of the side close to the screen of the first supporting part, the curvature radius R3 of the side far from the screen of the second lens and the curvature radius R4 of the side close to the screen of the second lens satisfy: -19.0 < d1m / (R3+R4) < 9.5.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical imaging, in particular to a visual optical system comprising a two-piece lens. BACKGROUND

[0002] In recent years, with the concept of "Meta Universe" being proposed, people's way of entertainment is becoming increasingly rich, among which, Augmented Reality (AR) and Virtual Reality (VR) devices and the like of human-computer interaction are increasingly favored by people. However, the common shortcomings of the current VR lenses are large volume, heavy weight and dizziness. Therefore, miniaturization, light weight and imaging quality of the lens become the most important factors to improve the experience of consumers.

[0003] Based on the above needs, Fresnel scheme and light path return scheme are proposed. The Fresnel scheme removes the straight propagation part and only retains the curved surface where refraction occurs, thereby reducing the lens thickness, so as to reduce the length and weight of the lens. The light path return scheme is to make the body length of the lens be compressed to half of the original, so as to make the center of gravity of the head-mounted device move backward, thereby increasing the experience of consumers. However, from the user experience, the weight and thickness of some devices using the Fresnel scheme and the light path return scheme still need to be improved, and the imaging quality cannot meet the user's needs due to the problems of chromatic aberration, aberration and various stray light.

[0004] Therefore, there is a need for a visual optical system that can meet the high experience of users, reduce the volume and weight, ensure the performance of the outer field of view and improve the imaging quality. SUMMARY

[0005] According to one aspect of the present application, a visual optical system is provided, which comprises a first lens group and a second lens group in sequence from the screen side to the screen side along the optical axis, the first lens group comprising a first lens, a reflective polarizing element and a quarter-wave plate; the second lens group comprising a second lens and a partial reflection layer; wherein the screen side of the first lens or the screen side of the second lens is a Fresnel surface; the visual optical system further comprises a lens barrel and a first supporting member placed on the screen side of the first lens, the first supporting member at least partially contacts the screen side of the first lens or the screen side of the second lens; the first lens group, the second lens group and the first supporting member are all contained in the lens barrel, wherein the inner diameter of the screen side and the screen side of the first supporting member is greater than 50mm, and the inner diameter d1m of the screen side of the first supporting member, the curvature radius R3 of the screen side of the second lens and the curvature radius R4 of the screen side of the second lens satisfy: -19.0 < d1m / (R3+R4) < 9.5.

[0006] According to another aspect of the present application, a visual optical system is provided, which comprises, in order from a screen-remote side to a screen-close side along an optical axis, a first lens group and a second lens group. The first lens group comprises a first lens, a reflective polarizing element and a quarter-wave plate. The second lens group comprises a second lens and a partial reflection layer. The screen-remote side surface of the first lens or the screen-remote side surface of the second lens is a Fresnel surface. The visual optical system further comprises a lens barrel and a first bearing member disposed on the screen-close side of the first lens. The first bearing member at least partially contacts the screen-close side of the first lens or the screen-remote side of the second lens. The first lens group, the second lens group and the first bearing member are all accommodated inside the lens barrel. The inner diameter of the screen-remote side and the screen-close side of the first bearing member is greater than 50 mm. The effective focal length F1 of the first lens group, the curvature radius R1 of the screen-remote side surface of the first lens, the outer diameter D1s of the screen-remote side of the first bearing member and the inner diameter d1s of the screen-remote side of the first bearing member satisfy the condition: 0.8 < F1 / R1 + D1s / d1s < 3.5.

[0007] In some embodiments, the visual optical system further comprises a first auxiliary bearing member. The first auxiliary bearing member is disposed on the screen-remote side of the first lens and at least partially contacts the screen-remote side surface of the first lens, or is disposed on the screen-remote side of the second lens and at least partially contacts the screen-remote side surface of the second lens.

[0008] In some embodiments, the reflective polarizing element and the quarter-wave plate are sequentially attached to the screen-close side surface of the first lens, and the partial reflection layer is attached to the screen-close side surface of the second lens.

[0009] In some embodiments, the effective focal length F1 of the first lens group, the curvature radius R1 of the screen-remote side surface of the first lens, the outer diameter D1s of the screen-remote side of the first bearing member and the inner diameter d1s of the screen-remote side of the first bearing member satisfy the condition: 0.8 < F1 / R1 + D1s / d1s < 3.5.

[0010] In some embodiments, the distance EP01 on the optical axis between the surface of the lens barrel on the screen-remote side to the surface of the first bearing member on the screen-remote side and the central thickness CT1 of the first lens satisfy the condition: 1.0 < EP01 / CT1 < 2.5.

[0011] In some embodiments, the outer diameter D1s of the screen-remote side of the first bearing member, the effective focal length F1 of the first lens group and the effective focal length F2 of the second lens group satisfy the condition: 0 mm < D1s / (F1 / F2) < 7.0 mm.

[0012] In some embodiments, the interval distance between the first lens group and the second lens group is less than 1.0 mm, and the maximum thickness CP1 of the first abutment, the inner diameter d1m of the first abutment near the screen side, and the inner diameter d1s of the first abutment away from the screen side satisfy: 0 mm < CP1 / (d1m / d1s) < 4.0 mm.

[0013] In some embodiments, the outer diameter D0m of the lens barrel near the screen side, the outer diameter D0s of the lens barrel away from the screen side, and the distance TD on the optical axis from the screen side face of the first lens to the screen side face of the second lens satisfy: 6.0 < (D0m+D0s) / TD < 8.5.

[0014] In some embodiments, the inner diameter d0s of the lens barrel away from the screen side, the inner diameter d1bs of the first auxiliary abutment away from the screen side, and the F number Fno of the visual optical system satisfy: 7.5 < d0s / d1bs*Fno < 10.5.

[0015] In some embodiments, the outer diameter D0m of the lens barrel near the screen side and the inner diameter d0m of the lens barrel near the screen side satisfy: 309.5 mm 2 <π(D0m 2 -d0m 2 )<393.0 mm 2 , where π is the circular ratio.

[0016] In some embodiments, the distance from the screen side face of the second lens to the screen is less than 20.0 mm, and the inner diameter d0m of the lens barrel near the screen side and the curvature radius R4 of the screen side face of the second lens satisfy: |d0m / R4| < 0.8.

[0017] In some embodiments, the maximum height L of the lens barrel, the distance EP01 on the optical axis from the screen side face of the lens barrel to the screen side face of the first abutment, the maximum thickness CP1 of the first abutment, and the central thickness CT2 of the second lens satisfy: (L-EP01-CP1) / CT2 < 1.0.

[0018] In some embodiments, the curvature radius R2 of the screen side face of the first lens, the curvature radius R3 of the screen side face of the second lens, and the inner diameter d1s of the screen side face of the first abutment satisfy: -38.0 < (R2+R3) / d1s < -8.5.

[0019] In some embodiments, the effective focal length F of the visual optical system and the maximum height L of the lens barrel satisfy: 1.5 < F / L < 2.5.

[0020] In some embodiments, the basic curvature of the Fresnel face is less than 10 -6 .

[0021] In some embodiments, the maximum thickness of the first abutment is greater than 0.2 mm, and the first abutment is at least partially in contact with the inner wall of the lens barrel.

[0022] According to an aspect of the present application, a visual optical system is provided, which comprises a lens barrel, a first lens group, a second lens group, and a first abutment. By changing the aspheric surface into a Fresnel surface, the thickness of the surface is reduced, which can effectively combine with the plane or curved surface of the next surface, reduce the thickness caused by the height, reduce the length of the optical system, and better balance the length and performance of the return optical system. By reasonably designing the related parameters and structure forms of the lenses, abutments, lens barrels and other optical elements, the inner diameter of the first abutment is greater than 50 mm, so that the inner diameter of the abutment after the light passes through the return and the Fresnel surface is set to block the excess light at the edge while ensuring complete imaging, and the curvature radius of the second lens away from the screen side is limited, which can effectively control the curvature radius of the two surfaces of the second lens within a certain range, limit the refractive power value of the second lens to make the light rays more optimal, and limit the shape of the aspheric surface of the second lens to ensure the machinability of the lens. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the following drawings:

[0024] Figure 1 The structure and part of the parameter schematic diagram of the visual optical system according to the embodiment of the present application are shown;

[0025] Figure 2A And Figure 2B The structure schematic diagram of the visual optical system with a Fresnel surface according to the embodiment of the present application is shown;

[0026] Figure 3 The optical path return schematic diagram of the visual optical system according to the embodiment of the present application is shown;

[0027] Figure 4 The structure schematic diagram of the visual optical system according to the embodiment 1 of the present application is shown;

[0028] Figure 5 The structure schematic diagram of the visual optical system according to the embodiment 2 of the present application is shown;

[0029] Figure 6A And Figure 6B The on-axis chromatic aberration curve and the astigmatism curve of the visual optical system according to the embodiment 1 and the embodiment 2 of the present application are shown;

[0030] Figure 7 The structure schematic diagram of the visual optical system according to the embodiment 3 of the present application is shown;

[0031] Figure 8 A structural schematic diagram of a visual optical system according to Embodiment 4 of the present application is shown;

[0032] Figure 9A and Figure 9B Axial chromatic aberration curves and astigmatism curves of the visual optical systems according to Embodiments 3 and 4 of the present application are shown, respectively;

[0033] Figure 10 A structural schematic diagram of a visual optical system according to Embodiment 5 of the present application is shown;

[0034] Figure 11 A structural schematic diagram of a visual optical system according to Embodiment 6 of the present application is shown;

[0035] Figure 12A and Figure 12B Axial chromatic aberration curves and astigmatism curves of the visual optical systems according to Embodiments 5 and 6 of the present application are shown, respectively;

[0036] Figure 13 A structural schematic diagram of a visual optical system according to Embodiment 7 of the present application is shown;

[0037] Figure 14 A structural schematic diagram of a visual optical system according to Embodiment 8 of the present application is shown;

[0038] Figure 15A and Figure 15B Axial chromatic aberration curves and astigmatism curves of the visual optical systems according to Embodiments 7 and 8 of the present application are shown, respectively;

[0039] Figure 16 A structural schematic diagram of a visual optical system according to Embodiment 9 of the present application is shown;

[0040] Figure 17 A structural schematic diagram of a visual optical system according to Embodiment 10 of the present application is shown; and

[0041] Figure 18A and Figure 18B Axial chromatic aberration curves and astigmatism curves of the visual optical systems according to Embodiments 9 and 10 of the present application are shown, respectively. DETAILED DESCRIPTION

[0042] For a better understanding of the present application, various aspects of the present application will be presented in more detail by reference to the attached drawings. It should be understood that these detailed description is merely a description of exemplary embodiments of the present application and is not intended in any way to limit the scope of the present application. Throughout the specification, like drawing reference numerals refer to like elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0043] It should be noted that the expressions first, second, third and the like in this specification are used only to distinguish one feature from another feature, and do not indicate any limitation on the features. Thus, the first lens discussed below can also be referred to as a second lens or a third lens without departing from the teachings of the present application.

[0044] In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for the sake of explanation. Specifically, the shape of the spherical surface or aspherical surface shown in the drawings is shown by way of example. That is, the shape of the spherical surface or aspherical surface is not limited to the shape of the spherical surface or aspherical surface shown in the drawings. The drawings are merely examples and are not drawn to scale.

[0045] In this specification, the paraxial region refers to a region near the optical axis. If a lens surface is convex and the position of the convex surface is not specified, it means that the lens surface is convex at least in the paraxial region. If a lens surface is concave and the position of the concave surface is not specified, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is referred to as the object side surface of the lens, and the surface of each lens closest to the image plane is referred to as the image side surface of the lens.

[0046] It should also be understood that the use of the terms "include", "includes", "including", "has", "have", "having", "comprises", "comprising", or "contains" or "containing", when used in this specification, indicates the presence of the stated features, elements, and / or components, but do not preclude the presence or addition of one or more other features, elements, components, and / or groups thereof. In addition, when expressions such as "at least one of" appear after the conjunction "or", they are intended to mean any one of the listed items or any combination of one or more of the listed items. In addition, when describing embodiments of the present application, the use of "may" indicates that "one or more embodiments of the present application". Also, the term "exemplary" is intended to refer to an example or illustration.

[0047] Unless otherwise defined, all terms used in this specification, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that the terms used herein, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0048] It should be noted that the embodiments and features in the present application can be combined with each other without conflict. The following embodiments only express several implementation manners of the present application, which are described in detail and specifically, but should not be understood as limitation to the patent scope of the present application. It should be noted that, for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the protection scope of the present application. For example, the lens group (i.e. the first lens to the sixth lens), the barrel structure and the spacer element in each embodiment of the present application can be combined arbitrarily, and are not limited to the combination of the lens group, the barrel structure, the spacer element and the like in the embodiment.

[0049] The features, principles and other aspects of the present application are described in detail below.

[0050] Reference Figure 1 According to the visual optical system of the embodiment of the present application, the first lens group and the second lens group are sequentially arranged from the screen side to the screen side along the optical axis. The first lens group can include the first lens E1, the reflective polarizing element RP and the quarter-wave plate QWP; the second lens group can include the second lens E2 and the partial reflection layer BS. The first lens E1 and the second lens E2 respectively have an incident surface close to the screen side and an emergent surface away from the screen side. The first lens E1 and the second lens E2 can have a spacing distance therebetween.

[0051] According to the visual optical system provided by the embodiment of the present application, the lens structure containing two pieces is adopted, so that the lens structure is more compact and light, and the structure design is optimized to eliminate chromatic aberration, phase difference and various stray light problems, and the forming quality is improved.

[0052] In the exemplary embodiment, the screen side surface (emergent surface) of the first lens E1 or the screen side surface (emergent surface) of the second lens E2 is a Fresnel surface. By replacing the aspherical surface lens with the Fresnel surface, the thickness of the surface is reduced, which can effectively combine with the plane or curved surface of the next surface, reduce the thickness caused by the height, reduce the length of the optical system, and better balance the length and performance of the return type optical system.

[0053] In the exemplary embodiment, the first lens group can have a positive focal power. The screen side surface (incident surface) of the first lens E1 is sequentially attached with the reflective polarizing element RP and the quarter-wave plate QWP.

[0054] As an exemplary embodiment, the reflective polarizing element RP and the quarter-wave plate QWP are designed on the same side of the first lens E1, and the two can be combined together to achieve one-time attachment, thereby improving production efficiency and reducing cost; at the same time, the combination of the two can avoid the angle deviation of the optical axis of the reflective polarizing element and the optical axis of the quarter-wave plate caused by the attachment process, and improve the imaging effect; in addition, through the above setting, it can also be controlled that the returned light is in the range of the second lens and the gap between the first lens, so that only the lens stress of the second lens needs to be controlled, and the material and forming requirements of the first lens are reduced.

[0055] In an exemplary embodiment, the second lens group can have positive refractive power. The partial reflection layer BS is attached to the screen side (light entrance surface) of the second lens E2.

[0056] In an exemplary embodiment, the visual optical system can further include a first supporting piece P1 located between the first lens E1 and the second lens E2, which can be placed on the screen side of the first lens E1 and at least partially in contact with the screen side of the first lens E1 or the screen side of the second lens E2, for example, the first supporting piece P1 can be arranged on the light entrance surface of the first lens E1 or the light exit surface of the second lens E2.

[0057] In an exemplary embodiment, the visual optical system can further include a lens barrel P0, and the first lens group, the second lens group and the first supporting piece P1 are all accommodated inside the lens barrel P0.

[0058] As shown in Figure 2A and Figure 2B , according to the visual optical system with a Fresnel surface according to the embodiments of the present application, the light exit surface of the first lens E1 is a Fresnel surface, or the light exit surface of the second lens E2 is a Fresnel surface.

[0059] According to the visual optical system of the exemplary embodiments of the present application, the inner diameter of the first bearing piece P1 on the side away from the screen and the side close to the screen is greater than 50 mm, and the visual optical system can satisfy -19.0 < d1m / (R3+R4) < 9.5, wherein d1m is the inner diameter of the side close to the screen of the first bearing piece P1, R3 is the curvature radius of the light-out surface of the second lens E2, and R4 is the curvature radius of the light-in surface of the second lens. According to the visual optical system of the embodiments of the present application, the inner diameter of the first bearing piece is greater than 50 mm, so that the inner diameter of the bearing piece provided after the light is folded and the Fresnel surface can block the excess light rays at the edge while ensuring complete imaging, and the curvature radius of the side of the second lens away from the screen can be limited, which can effectively control the curvature radius of the two surfaces of the second lens within a certain range, thereby limiting the optical power value of the second lens and making the light rays more optimal, and also limiting the shape of the aspheric lens of the second lens to ensure the machinability of the lens. Meanwhile, when the side of the second lens away from the screen (i.e., the light-out surface) is a Fresnel surface, limiting the curvature radius can effectively control the height of the Fresnel teeth within a certain range, which can prevent the Fresnel teeth from being too high, making the machining difficult, the demolding difficult, and the imaging quality low, and can also ensure the Fresnel teeth within a certain height to avoid the optimization of the lens thickness and weight being too small.

[0060] According to the visual optical system of the exemplary embodiments of the present application, the inner diameter of the first bearing piece P1 on the side away from the screen and the side close to the screen is greater than 50 mm, and the visual optical system can satisfy -19.0 < d1m / (R3+R4) < 9.5, wherein d1m is the inner diameter of the side close to the screen of the first bearing piece P1, R3 is the curvature radius of the light-out surface of the second lens E2, and R4 is the curvature radius of the light-in surface of the second lens. According to the visual optical system of the embodiments of the present application, the inner diameter of the first bearing piece is greater than 50 mm, so that the inner diameter of the bearing piece provided after the light is folded and the Fresnel surface can block the excess light rays at the edge while ensuring complete imaging, and the curvature radius of the side of the second lens away from the screen can be limited, which can effectively control the curvature radius of the two surfaces of the second lens within a certain range, thereby limiting the optical power value of the second lens and making the light rays more optimal, and also limiting the shape of the aspheric lens of the second lens to ensure the machinability of the lens. Meanwhile, when the side of the second lens away from the screen (i.e., the light-out surface) is a Fresnel surface, limiting the curvature radius can effectively control the height of the Fresnel teeth within a certain range, which can prevent the Fresnel teeth from being too high, making the machining difficult, the demolding difficult, and the imaging quality low, and can also ensure the Fresnel teeth within a certain height to avoid the optimization of the lens thickness and weight being too small.

[0061] The visual optical system provided by some embodiments of the present application can be used in a virtual reality device, which combines the Fresnel scheme and the light path folding scheme. The Fresnel scheme removes the straight propagation part and only retains the curved surface that refracts, thereby reducing the lens thickness, so as to realize the reduction of the lens length and weight. The light path folding scheme compresses the body length of the lens to half of the original length by folding the light path, so as to move the center of gravity of the head-mounted device backward and increase the experience of consumers.

[0062] In the exemplary embodiments, the light-in surface of the first lens E1 can be a spherical surface or an aspherical surface, which can ensure that the light rays can be deflected well when passing through the first lens E1.

[0063] In the example embodiment, the light-incident surface and the light-emanating surface of the second lens E2 can both be convex.

[0064] In the example embodiment, the light-incident surface of the second lens E2 is aspherical and attached with a partial reflection layer BS to realize light turning back in the second lens E2 and reduce the height of the optical system.

[0065] Reference Figure 3 As shown, the visual optical system according to the embodiment of the present application utilizes the polarization characteristics of light to make the image light from the screen multiple reflect and refract in the second lens E2 and the first lens E1, shorten the length of the optical system by increasing the turning back times of the image light, and also reduce the number of optical lenses used, achieving the advantages of small volume, light weight and high resolving power.

[0066] Reference Figure 1 In the example embodiment, the visual optical system can further include a first auxiliary bearing piece P1b, which can be located on the side of the first lens E1 away from the screen and can be at least partially in contact with the light-emanating surface of the first lens E1, for example, can abut against the light-emanating surface of the first lens E1. Alternatively, the first auxiliary bearing piece P1b can also be located on the side of the second lens E2 away from the screen and can be at least partially in contact with the light-emanating surface of the second lens E2, for example, can abut against the light-emanating surface of the second lens E2. Since the thickness specification of the first auxiliary bearing piece P1b is easier to control, by selecting first auxiliary bearing pieces of different thicknesses, a reasonable range of air gap between lenses of different thicknesses can be achieved, ensuring that the production lens field curvature is within a certain range, thereby reducing the tolerance requirement of lens thickness and improving the utilization rate of lenses.

[0067] In the example embodiment, the visual optical system can satisfy the following conditional expression: 1.0 < EP01 / CT1 < 2.5, where EP01 is the distance on the optical axis from the surface of the lens barrel away from the screen to the surface of the first bearing piece away from the screen, and CT1 is the center thickness of the first lens. By limiting the thickness of the lens barrel top surface and the center thickness of the first lens within a certain range, the structural strength of the system can be ensured, and the processability of the first lens can also be ensured.

[0068] In the example embodiment, the visual optical system can satisfy the following conditional expression: 0 mm < D1s / (F1 / F2) < 7.0 mm, where D1s is the outer diameter of the first bearing piece away from the screen, F1 is the effective focal length of the first lens group, and F2 is the effective focal length of the second lens group. By controlling the effective focal lengths of the first lens group and the second lens group within a certain range, the optical power of the system is reasonably distributed, the system aberration is corrected, and the imaging quality of the system is improved under the premise of meeting the system focal length.

[0069] In the example embodiment, the interval distance between the first lens group and the second lens group is less than 1.0 mm, and the visual optical system can satisfy the following conditional expression: 0 mm < CP1 / (d1m / d1s) < 4.0 mm, wherein CP1 is the maximum thickness of the first bearing piece, d1m is the inner diameter of the first bearing piece on the side close to the screen, and d1s is the inner diameter of the first bearing piece on the side away from the screen. Satisfying the conditional expression can control the shape of the first bearing piece, which can limit the bearing area of the first bearing piece on the side close to the screen to ensure the support of the second lens, and limit the diameter-thickness ratio of the first bearing piece to ensure the processability.

[0070] In the example embodiment, the visual optical system can satisfy the following conditional expression: 6.0 < (D0m+D0s) / TD < 8.5, wherein D0m is the outer diameter of the lens barrel on the side close to the screen, D0s is the outer diameter of the lens barrel on the side away from the screen, and TD is the distance on the optical axis from the surface of the first lens on the side away from the screen to the surface of the second lens on the side close to the screen. By limiting the shape of the lens barrel structure and controlling the diameter-thickness ratio of the lens barrel, on the one hand, the lens barrel outer diameter is prevented from being too large to affect the assembly space of the whole machine design; on the other hand, the lens barrel outer diameter is prevented from being too small, which is difficult to process and form.

[0071] In the example embodiment, the visual optical system can satisfy the following conditional expression: 7.5 < d0s / d1bs*Fno < 10.5, wherein d0s is the inner diameter of the lens barrel on the side away from the screen, d1bs is the inner diameter of the first auxiliary bearing piece on the side away from the screen, and Fno is the aperture number of the visual optical system. Satisfying the conditional expression can control the system light inlet aperture to absorb the excess light from the screen side, which can avoid being too large to generate excess stray light, and can also prevent being too small to make the image too small and affect the user experience effect.

[0072] In the example embodiment, the visual optical system can satisfy the following conditional expression: 309.5 mm < D0m < 393.0 mm 2 <π(D0m 2 -d0m 2 )<393.0mm 2 wherein D0m is the outer diameter of the lens barrel on the side close to the screen, d0m is the inner diameter of the lens barrel on the side close to the screen, and π is the circular ratio. By limiting the shape of the lens barrel, the inner diameter of the lens barrel on the side close to the screen can be prevented from being too small to limit the effective display range of the screen, and the inner diameter of the lens barrel on the side close to the screen can be prevented from being too large to generate additional stray light; at the same time, by limiting the inner and outer diameters of the lens barrel on the side close to the screen, the lens barrel can have a reasonable bearing support area, which can satisfy the support structure characteristics of the lens barrel and the processability of the lens barrel.

[0073] In the example embodiment, the distance from the light entrance surface of the second lens to the screen is less than 20.0 mm, and the visual optical system can satisfy the following conditional expression: |d0m / R4|<0.8, where d0m is the inner diameter of the lens barrel on the side close to the screen, and R4 is the curvature radius of the light entrance surface of the second lens. By limiting the structure of the second lens, which is the core lens of the folded optical path, the structure is more reasonable, which is beneficial to the processability of the second lens and the performance of the whole lens.

[0074] In the example embodiment, the visual optical system can satisfy the following conditional expression: (L-EP01-CP1) / CT2<1.0, where L is the maximum height of the lens barrel, EP01 is the distance on the optical axis between the surface of the lens barrel on the side away from the screen and the surface of the first bearing on the side away from the screen, and CP1 is the maximum thickness of the first bearing. Satisfying the conditional expression can prevent the lens barrel from being too long, affecting the TTL of the whole machine, and can also reasonably allocate the thickness of each lens component to ensure the processability of each component.

[0075] In the example embodiment, the visual optical system can satisfy the following conditional expression: -38.0<(R2+R3) / d1s<-8.5, where R2 is the curvature radius of the light entrance surface of the first lens, R3 is the curvature radius of the light exit surface of the second lens, and d1s is the inner diameter of the first bearing on the side away from the screen. Satisfying the conditional expression can limit the light path between the first lens and the second lens. Since the light entrance surface on the side close to the screen of the first lens is attached with a reflective polarizing element and a quarter-wave plate, the light reflection angle between the first lens and the second lens is prevented from being too large, which affects the polarization characteristics of the reflective polarizing element and the quarter-wave plate. At the same time, in combination with the limitation of the inner diameter of the first bearing on the side away from the screen, the stray light between the first lens and the second lens can be controlled, and the imaging quality can be improved.

[0076] In the example embodiment, the visual optical system can satisfy the following conditional expression: 1.5<F / L<2.5, where F is the effective focal length of the visual optical system, and L is the maximum height of the lens barrel. Satisfying the conditional expression can control the focal length of the optical imaging system, effectively constrain the field of view angle of the system, so that the system meets the characteristics of the large field of view of the VR lens, and at the same time, the maximum height of the lens barrel is limited, the length of the whole machine is compressed, and the user experience is ensured.

[0077] In the example embodiment, the basic curvature of the Fresnel surface of the visual optical system is less than 10 -6 By limiting the basic curvature of the Fresnel surface to be less than 10 -6 , the height of the Fresnel tooth can be prevented from being too large, which can ensure the good processability of the Fresnel surface and prevent the ghost distortion caused by the Fresnel surface from being too large, which affects the experience effect.

[0078] In the exemplary embodiment, the maximum thickness of the first abutting member of the visual optical system is greater than 0.2 mm, and the first abutting member is at least partially in contact with the inner wall of the lens barrel. When the gap between the first lens and the second lens is large, the edge thickness of the lens cannot be greatly increased to ensure the molding of the lens. Therefore, an abutting member is needed to form an assembly support. In order to ensure that the inside of the abutting diameter can shield stray light, the outer diameter of the abutting diameter needs to be partially in contact with the inner wall of the lens barrel.

[0079] According to the visual optical system of the above-mentioned embodiments of the present application, two lenses can be used. By reasonably allocating the focal length, surface shape, central thickness of each lens, and axial distance between the lenses, the incident light can be effectively converged, the total optical length can be reduced, and the processability can be improved, so that the visual optical system is more conducive to production and processing.

[0080] In the embodiments of the present application, at least one of the optical surfaces of each lens in the first lens and the second lens is a non-spherical mirror surface. The non-spherical lens has the characteristic that the curvature continuously changes from the center of the lens to the periphery of the lens. Unlike the spherical lens which has a constant curvature from the center of the lens to the periphery of the lens, the non-spherical lens has better curvature radius characteristics, and has the advantages of improving distortion aberration and improving astigmatism aberration. After using the non-spherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0081] Embodiments 1 to 10 of the visual optical system applicable to the above-mentioned exemplary embodiments will be further described below with reference to the accompanying drawings and in conjunction with examples.

[0082] Example 1

[0083] Figure 4 A structure schematic diagram of the visual optical system according to Embodiment 1 of the present application is shown. As shown in Figure 4 the visual optical system includes a lens barrel P0 and a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2 and a screen arranged in the lens barrel P0 in order from the screen side to the screen side along the optical axis. The first lens E1 has an outlight surface S1 away from the screen side and an inlight surface S2 close to the screen side. The second lens E2 has an outlight surface S5 away from the screen side and an inlight surface S6 close to the screen side.

[0084] In this embodiment, the first lens E1, the reflective polarizing element RP and the quarter-wave plate QWP can constitute a first lens group. Specifically, the light entrance surface S2 of the first lens E1 is sequentially attached with the reflective polarizing element RP and the quarter-wave plate QWP, and the reflective polarizing element RP and the quarter-wave plate QWP have optical surfaces S3 and S4, respectively. When the light passes through the reflective polarizing element RP, the reflective polarizing element can reflect light in a certain direction and can transmit light orthogonal to the reflected light. The quarter-wave plate QWP can be used to convert between circularly polarized light and linearly polarized light, achieve a turn-back of the optical path, and facilitate shortening the length of the visual optical system.

[0085] In this embodiment, the second lens E2 and the partial reflection layer BS constitute a second lens group. Specifically, the partial reflection layer BS is attached to the light entrance surface S6 of the second lens E2. The partial reflection layer BS has a semi-transmissive and semi-reflective effect on light. By providing the partial reflection layer BS on the light entrance surface S6 of the second lens E2, in combination with the reflective polarizing element RP and the quarter-wave plate QWP, the light can be turned back multiple times, thereby effectively reducing the length of the visual optical system.

[0086] In this embodiment, the light exit surface S1 of the first lens E1 is a thin Fresnel surface. The use of a Fresnel surface reduces the thickness of the surface, which can effectively combine with the plane or curved surface of the next surface to reduce the thickness caused by the height.

[0087] In this embodiment, the visual optical system can further include a first supporting member P1 located between the first lens E1 and the second lens E2, the first supporting member P1 can at least partially contact the side of the second lens E2 away from the screen, for example, can abut against the light exit surface S5 of the second lens E2 and at least partially contact the inner wall of the lens barrel P0; and a first auxiliary supporting member P1b located on the side of the first lens E1 away from the screen, the first auxiliary supporting member P1b can at least partially contact the side of the first lens E1 away from the screen and the inner wall of the lens barrel P0.

[0088] In this embodiment, the first lens E1 has a positive focal power, and the light exit surface S1 of the first lens E1 can be a convex surface.

[0089] In this embodiment, the second lens E2 has a positive focal power, and the light entrance surface S6 and the light exit surface S5 of the second lens E2 can both be convex surfaces.

[0090] In this embodiment, as an exemplary embodiment, the light entrance surface S2 of the first lens E1 can be a plane, facilitating the attachment of the reflective polarizing element RP and the quarter-wave plate QWP.

[0091] As an exemplary embodiment, the reflective polarizing element RP is combined with the quarter-wave plate QWP, avoiding separate attachment of the reflective polarizing element RP and the quarter-wave plate QWP, and improving the attachment efficiency.

[0092] As an exemplary embodiment, the light entrance surface S6 of the second lens E2 can be aspherical. The light exit surface S1 of the first lens E1 is aspherical, and the light entrance surface S2 can be spherical or aspherical. An aspherical lens has better curvature radius characteristics, and has the advantages of improving the distortion aberration and improving the astigmatism aberration. By using an aspherical lens, the aberration that occurs during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0093] In this embodiment, the visual optical system can further include a stop STO arranged on the side away from the screen. The image light from the screen is incident on the stop STO after multiple refractions and reflections of the second lens E2 and the first lens E1, and then enters the human eye. Specifically, the image light from the display screen passes through the second lens E2 and the quarter-wave plate QWP in sequence to reach the reflective polarizing element RP, is then reflected at the reflective polarizing element RP, and passes through the quarter-wave plate QWP and the second lens E2 again to reach the partially reflective layer BS, after which the light beam is reflected at the partially reflective layer BS and is incident on the stop STO after passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 in sequence, and then exits towards the human eye side. According to the visual optical system provided in the present application, the required optical path is folded in a combination of light reflection and refraction without affecting the imaging quality, effectively shortening the length of the visual optical system.

[0094] Example 2

[0095] Figure 5 A structure schematic diagram of a visual optical system according to Embodiment 2 of the present application is shown. In this embodiment 2 and the following embodiments, part of the description similar to Embodiment 1 will be omitted for brevity.

[0096] As Figure 5 shown, the visual optical system barrel P0 of the present embodiment and the first lens E1, the reflective polarizing element RP, the quarter-wave plate QWP, the second lens E2, the partially reflective layer BS and the screen arranged in sequence from the side away from the screen to the side close to the screen. The light exit surface S1 of the first lens E1 is a thin Fresnel surface.

[0097] In this embodiment, the visual optical system can further include a first abutment P1 located between the first lens E1 and the second lens E2, the first abutment P1 can be at least partially in contact with the screen-remote side of the second lens E2, for example, can abut on the light-out surface S5 of the second lens E2 and be at least partially in contact with the inner wall of the lens barrel P0; and a first auxiliary abutment P1b located on the screen-remote side of the first lens E1, the first auxiliary abutment P1b can be at least partially in contact with the screen-remote side of the first lens E1 and the inner wall of the lens barrel P0.

[0098] The following Table 1 shows the basic parameter table of the visual optical systems of Embodiment 1 and Embodiment 2, wherein the units of the radius of curvature, thickness / distance are millimeters (mm).

[0099]

[0100]

[0101] Table 1

[0102] In Embodiment 1 and Embodiment 2, the light-out surface S1 of the first lens E1 and the light-in surface S6 of the second lens E2 are aspherical surfaces, and the surface type x of each aspherical surface can be defined by, but not limited to, the following aspherical surface formula:

[0103]

[0104] wherein x is the distance sag of the aspherical surface at a height h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the inverse of the radius of curvature R in Table 1 above); k is the conic coefficient; and Ai is the correction coefficient of the i-th order of the aspherical surface.

[0105] Table 2 gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16 and A18 of the aspherical surfaces S1 and S6 that can be used in Embodiment 1 and Embodiment 2. 10 12 14 16 18 20 .

[0106] Face No. A4 A6 A8 A10 A12 S1 1.04E-06 -9.87E-11 0.00E+00 0.00E+00 0.00E+00 S6 1.49E-07 3.55E-11 0.00E+00 0.00E+00 0.00E+00 Face No. A14 A16 A18 A20 S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0107] Table 2

[0108] Figure 6A The on-axis chromatic aberration curves of the visual optical systems of Embodiment 1 and Embodiment 2 are shown, which represent the deviation of the converging focal points of light rays of different wavelengths after passing through the lens. Figure 6B The astigmatism curves of the visual optical systems of Embodiment 1 and Embodiment 2 are shown, which represent the meridional image curvature and sagittal image curvature. According to the astigmatism curves, the meridional image curvature and the sagittal image curvature of the visual optical systems of Embodiment 1 and Embodiment 2 are shown.​​​​​Figure 6A and Figure 6B It can be seen that the visual optical system given in Embodiment 1 and Embodiment 2 can achieve good imaging quality.

[0109] Example 3

[0110] Figure 7 A structure diagram of a visual optical system according to Embodiment 3 of the present application is shown. As shown in the figure, the visual optical system comprises a lens barrel P0 and, arranged in order from the side far away from the screen to the side close to the screen, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflection layer BS and a screen. In this embodiment, the light-out surface S5 of the second lens E2 is a thin Fresnel surface. Figure 7

[0111] In this embodiment, the visual optical system can further comprise a first abutting member P1 located between the first lens E1 and the second lens E2, which can be at least partially in contact with the side of the second lens E2 far away from the screen, for example, can abut against the light-out surface S5 of the second lens E2 and be at least partially in contact with the inner wall of the lens barrel P0; and a first auxiliary abutting member P1b located on the side of the first lens E1 far away from the screen, which can be at least partially in contact with the side of the first lens E1 far away from the screen and the inner wall of the lens barrel P0.

[0112] In this embodiment, the first lens E1 has positive focal power, and the light-out surface S1 of the first lens E1 can be a convex surface.

[0113] In this embodiment, the second lens E2 has positive focal power, and both the light-in surface S6 and the light-out surface S5 of the second lens E2 can be convex surfaces.

[0114] In this embodiment, as an exemplary implementation, the light-in surface S2 of the first lens E1 can be a plane, which facilitates the attachment of the reflective polarizing element RP and the quarter-wave plate QWP.

[0115] As an exemplary implementation, the reflective polarizing element RP and the quarter-wave plate QWP are compounded together, which avoids the separate attachment of the reflective polarizing element RP and the quarter-wave plate QWP and improves the attachment efficiency.

[0116] As an exemplary implementation, the light-out surface S5 and the light-in surface S6 of the second lens E2 can be aspherical surfaces. The light-out surface S1 of the first lens E1 is an aspherical surface, and the light-in surface S2 can be a spherical surface or an aspherical surface. The aspherical lens has better curvature radius characteristics and has the advantages of improving the distortion aberration and improving the astigmatism aberration. The use of the aspherical lens can eliminate the aberration as much as possible during imaging, thereby improving the imaging quality.

[0117] ​In this embodiment, the visual optical system may further include an aperture stop STO disposed on the side away from the screen. Image light emitted from the screen is refracted and reflected multiple times by the second lens E2 and the first lens E1 before entering the aperture stop STO and then the human eye. Specifically, image light from the display screen passes sequentially through the second lens E2 and the quarter-wave plate QWP to reach the reflective polarizing element RP, is then reflected at the reflective polarizing element RP, and passes again through the quarter-wave plate QWP and the second lens E2 to reach the partial reflective layer BS. Afterward, the light beam is reflected at the partial reflective layer BS and passes sequentially through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 before entering the aperture stop STO and exiting towards the human eye. According to the visual optical system provided in this application, by combining light reflection and refraction, the required optical path is folded without affecting the image quality, effectively shortening the overall length of the visual optical system.

[0118] Example 4

[0119] Figure 8 A schematic diagram of the visual optical system according to Embodiment 4 of this application is shown. Figure 8 As shown, the visual optical system of this embodiment includes a lens barrel P0 and a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflective layer BS, and a screen, arranged sequentially from the side furthest from the screen to the side closest to the screen. In this embodiment, the light-emitting surface S5 of the second lens E2 is a thin Fresnel surface.

[0120] In this embodiment, the visual optical system may further include a first support member P1 located between the first lens E1 and the second lens E2. The first support member P1 may at least partially contact the side of the second lens E2 away from the screen, for example, it may abut against the light-emitting surface S5 of the second lens E2 and at least partially contact the inner wall of the lens barrel P0; and include a first auxiliary support member P1b located on the side of the first lens E1 away from the screen. The first auxiliary support member P1b may at least partially contact the side of the first lens E1 away from the screen and the inner wall of the lens barrel P0.

[0121] Table 3 shows the basic parameters of the visual optical systems of Examples 3 and 4, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0122]

[0123]

[0124] Table 3

[0125] In Examples 3 and 4, the light-emitting surface S1 of the first lens E1, the light-emitting surface S5 of the second lens E2, and the light-incident surface S6 are all aspherical surfaces. The surface shape x of each aspherical lens can be limited by, but is not limited to, the above formula (1).

[0126] Table 4 lists the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1, S5, and S6 in Examples 3 and 4. 10 A 12 A 14 A 16 A 18 and A 20 .

[0127] Face No. A4 A6 A8 A10 A12 S1 1.09E-06 -1.81E-09 5.28E-12 -9.36E-15 0.00E+00 S5 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 5.34E-08 4.93E-10 0.00E+00 0.00E+00 0.00E+00 Face No. A14 A16 A18 A20 S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0128] Table 4

[0129] Figure 9A The on-axis chromatic aberration curves of the visual optical systems of Embodiments 3 and 4 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 9B Astigmatism curves for the visual optical systems of Examples 3 and 4 are shown, representing meridional and sagittal image plane curvature. According to... Figure 9A and Figure 9B It can be seen that the visual optical systems given in Examples 3 and 4 can achieve good imaging quality.

[0130] Example 5

[0131] Figure 10 A schematic diagram of the visual optical system according to Embodiment 5 of this application is shown. Figure 10 As shown, the visual optical system includes a lens barrel P0 and, arranged sequentially from the side furthest from the screen to the side closest to the screen, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflective layer BS, and a screen. In this embodiment, the light-emitting surface S1 of the first lens E1 is a thin Fresnel surface. Using a Fresnel surface reduces the thickness of this surface, effectively combining it with the planar or curved surface of the subsequent surface, and reducing the increase in thickness caused by the sag.

[0132] In this embodiment, the visual optical system may further include a first support member P1 located between the first lens E1 and the second lens E2. The first support member P1 may at least partially contact the side of the second lens E2 away from the screen, for example, it may abut against the light-emitting surface S5 of the second lens E2 and at least partially contact the inner wall of the lens barrel P0; and include a first auxiliary support member P1b located on the side of the first lens E1 away from the screen. The first auxiliary support member P1b may at least partially contact the side of the first lens E1 away from the screen and the inner wall of the lens barrel P0.

[0133] In this embodiment, the first lens E1 has positive focal power, and the light-out surface S1 of the first lens E1 can be a convex surface.

[0134] In this embodiment, the second lens E2 has positive focal power, and both the light-in surface S6 and the light-out surface S5 of the second lens E2 can be convex surfaces.

[0135] In this embodiment, the reflective polarizing element RP is combined with the quarter-wave plate QWP, avoiding separate attachment of the reflective polarizing element RP and the quarter-wave plate QWP, and improving the attachment efficiency.

[0136] In this embodiment, the light-in surface S6 of the second lens E2 can be an aspheric surface. Both the light-out surface S1 and the light-in surface S2 of the first lens E1 are aspheric surfaces. The aspheric lens has better curvature radius characteristics, and has the advantages of improving the distortion aberration and improving the astigmatism aberration. The use of the aspheric lens can eliminate the aberration as much as possible during imaging, thereby improving the imaging quality.

[0137] In this embodiment, the visual optical system can further include a stop STO arranged on the side away from the screen. The image light from the screen is incident on the stop STO after multiple refractions and reflections of the second lens E2 and the first lens E1, and then enters the human eye. Specifically, the image light from the display screen passes through the second lens E2 and the quarter-wave plate QWP in sequence to reach the reflective polarizing element RP, is then reflected at the reflective polarizing element RP, and passes through the quarter-wave plate QWP and the second lens E2 again to reach the partial reflection layer BS, after which the light beam is reflected at the partial reflection layer BS and passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 in sequence before being incident on the stop STO and then being emitted towards the human eye side. According to the visual optical system provided in the present application, the required optical path is folded in a combination of light reflection and refraction without affecting the imaging quality, effectively shortening the length of the visual optical system.

[0138] Example 6

[0139] Figure 11 A structure schematic diagram of a visual optical system according to Embodiment 6 of the present application is shown. As shown in the figure, the visual optical system includes a lens barrel P0 and, arranged in sequence from the side away from the screen to the side close to the screen, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflection layer BS, and a screen. Figure 11

[0140] In this embodiment, the light-out surface S1 of the first lens E1 is a thin Fresnel surface.

[0141] ​In this embodiment, the visual optical system may further include a first support member P1 located between the first lens E1 and the second lens E2. The first support member P1 may at least partially contact the screen-proximity side of the first lens E1, for example, it may abut against the light-incident surface S2 of the first lens E1 and at least partially contact the inner wall of the lens barrel P0; and a first auxiliary support member P1b located on the screen-remote side of the second lens E2. The first auxiliary support member P1b may at least partially contact the screen-remote side of the second lens E2 and the inner wall of the lens barrel P0.

[0142] Table 5 shows the basic parameters of the visual optical systems of Examples 5 and 6, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0143]

[0144]

[0145] Table 5

[0146] In Examples 5 and 6, the light-emitting surface S1 and light-incident surface S2 of the first lens E1 and the light-incident surface S6 of the second lens E2 are both aspherical surfaces, and the surface shape x of each aspherical lens can be limited by, but is not limited to, the above formula (1).

[0147] Table 6 lists the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1, S2, S3, S4, and S6 in Examples 5 and 6. 10 A 12 A 14 A 16 A 18 and A 20 .

[0148] Face No. A4 A6 A8 A10 A12 S1 5.31E-06 -8.82E-10 0.00E+00 0.00E+00 0.00E+00 S2 5.90E-07 6.10E-10 -1.15E-13 0.00E+00 0.00E+00 S3 5.90E-07 6.10E-10 -1.15E-13 0.00E+00 0.00E+00 S4 5.90E-07 6.10E-10 -1.15E-13 0.00E+00 0.00E+00 S6 5.08E-07 4.24E-10 0.00E+00 0.00E+00 0.00E+00 Face No. A14 A16 A18 A20 S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0149] Table 6

[0150] Figure 12A The on-axis chromatic aberration curves of the visual optical systems of Embodiments 5 and 6 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 12B Astigmatism curves for the visual optical systems of Embodiments 5 and 6 are shown, representing meridional and sagittal image plane curvature. According to... Figure 12A and Figure 12B It can be seen that the visual optical systems given in Examples 5 and 6 can achieve good imaging quality.

[0151] Example 7

[0152] Figure 13A structural diagram of a visual optical system according to Embodiment 7 of the present application is shown. As shown in the diagram, the visual optical system comprises a lens barrel P0 and, arranged in order from the side far from the screen to the side close to the screen, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partially reflective layer BS, and a screen. Figure 13

[0153] In this embodiment, the light-out surface S1 of the first lens E1 is a thin Fresnel surface. The use of a Fresnel surface reduces the thickness of the surface, which can effectively combine with the plane or curved surface of the next surface, reducing the thickness caused by the height.

[0154] In this embodiment, the visual optical system can further comprise a first supporting member P1 located between the first lens E1 and the second lens E2, which can be at least partially in contact with the side of the second lens E2 far from the screen, for example, can be in contact with the light-out surface S5 of the second lens E2 and can be at least partially in contact with the inner wall of the lens barrel P0; and a first auxiliary supporting member P1b located on the side of the first lens E1 far from the screen, which can be at least partially in contact with the side of the first lens E1 far from the screen and the inner wall of the lens barrel P0.

[0155] In this embodiment, the first lens E1 has a positive focal power, and the light-out surface S1 and the light-in surface S2 of the first lens E1 can both be convex.

[0156] In this embodiment, the second lens E2 has a positive focal power, and the light-in surface S6 and the light-out surface S5 of the second lens E2 can both be convex.

[0157] In this embodiment, the reflective polarizing element RP and the quarter-wave plate QWP are compounded together, avoiding the separation of the reflective polarizing element RP and the quarter-wave plate QWP, and improving the attachment efficiency.

[0158] In this embodiment, the light-in surface S6 of the second lens E2 can be an aspheric surface. The light-out surface S1 and the light-in surface S2 of the first lens E1 are both aspheric surfaces.

[0159] ​In this embodiment, the visual optical system can further include a light stop STO disposed on the side away from the screen. The image light from the screen enters the light stop STO after multiple refractions and reflections of the second lens E2 and the first lens E1, and then enters the human eye. Specifically, the image light from the display screen passes through the second lens E2 and the quarter-wave plate QWP in sequence to reach the reflective polarizing element RP, is then reflected at the reflective polarizing element RP, and passes through the quarter-wave plate QWP and the second lens E2 again to reach the partially reflective layer BS, after which the light beam is reflected at the partially reflective layer BS and enters the light stop STO after passing through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, and the first lens E1 in sequence, and then exits towards the side of the human eye. According to the visual optical system provided in the present application, the required optical path is folded in a combination of light reflection and refraction without affecting the imaging quality, effectively shortening the length of the body of the visual optical system.

[0160] Example 8

[0161] Figure 14 A structure diagram of a visual optical system according to Embodiment 8 of the present application is shown. As shown in Figure 14 the visual optical system includes a lens barrel P0 and, arranged in sequence from the side away from the screen to the side close to the screen, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partially reflective layer BS, and a screen.

[0162] In this embodiment, the light-out surface S1 of the first lens E1 is a thin Fresnel surface.

[0163] In this embodiment, the visual optical system can further include a first abutting member P1 located between the first lens E1 and the second lens E2, which can be at least partially in contact with the side close to the screen of the first lens E1, for example, can be abutted on the light-in surface S2 of the first lens E1 and can be at least partially in contact with the inner wall of the lens barrel P0, and a first auxiliary abutting member P1b located on the side away from the screen of the second lens E2, which can be at least partially in contact with the side away from the screen of the second lens E2 and the inner wall of the lens barrel P0.

[0164] Table 7 shows a table of basic parameters of the visual optical systems of Embodiment 7 and Embodiment 8, wherein the units of the radius of curvature and the thickness / distance are millimeters (mm).

[0165]

[0166] Table 7

[0167] In Examples 7 and 8, the light-emitting surface S1 and light-incident surface S2 of the first lens E1 and the light-incident surface S6 of the second lens E2 are both aspherical surfaces, and the surface shape x of each aspherical lens can be limited by, but is not limited to, the above formula (1).

[0168] Table 8 lists the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1, S2, S3, S4, and S6 in Examples 7 and 8. 10 A 12 A 14 A 16 A 18 and A 20 .

[0169] Face No. A4 A6 A8 A10 A12 S1 6.33E-06 -1.30E-09 0.00E+00 0.00E+00 0.00E+00 S2 6.51E-07 7.18E-10 -1.61E-13 0.00E+00 0.00E+00 S3 6.92E-07 7.22E-10 -1.51E-13 0.00E+00 0.00E+00 S4 6.50E-07 7.51E-10 -1.58E-13 0.00E+00 0.00E+00 S6 6.80E-07 4.67E-10 0.00E+00 0.00E+00 0.00E+00 Face No. A14 A16 A18 A20 S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S2 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S3 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0170] Table 8

[0171] Figure 15A The on-axis chromatic aberration curves of the visual optical systems of Embodiments 7 and 8 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 15B Astigmatism curves for the visual optical systems of Embodiments 7 and 8 are shown, representing meridional and sagittal image plane curvature. According to... Figure 15A and Figure 15B It can be seen that the visual optical systems given in Examples 7 and 8 can achieve good imaging quality.

[0172] Example 9

[0173] Figure 16 A schematic diagram of the visual optical system according to Embodiment 9 of this application is shown. Figure 16 As shown, the visual optical system includes a lens barrel P0 and a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflective layer BS, and a screen, arranged sequentially from the side furthest from the screen to the side closest to the screen.

[0174] In this embodiment, the light-emitting surface S5 of the second lens E2 is a thin Fresnel surface.

[0175] In this embodiment, the visual optical system may further include a first support member P1 located between the first lens E1 and the second lens E2. The first support member P1 may at least partially contact the side of the second lens E2 away from the screen, for example, it may abut against the light-emitting surface S5 of the second lens E2 and at least partially contact the inner wall of the lens barrel P0; and include a first auxiliary support member P1b located on the side of the first lens E1 away from the screen. The first auxiliary support member P1b may at least partially contact the side of the first lens E1 away from the screen and the inner wall of the lens barrel P0.

[0176] In this embodiment, the first lens E1 has positive refractive power, and the light-out surface S1 of the first lens E1 can be convex.

[0177] In this embodiment, the second lens E2 has positive refractive power, and both the light-in surface S6 and the light-out surface S5 of the second lens E2 can be convex.

[0178] As an exemplary embodiment, the reflective polarizing element RP is combined with the quarter-wave plate QWP, avoiding separate attachment of the reflective polarizing element RP and the quarter-wave plate QWP, and improving the attachment efficiency.

[0179] In this embodiment, the light-in surface S6 of the second lens E2 can be aspherical. The light-out surface S1 of the first lens E1 is aspherical, and the light-in surface S2 can be spherical.

[0180] In this embodiment, the visual optical system can further include a stop STO arranged on the side away from the screen. The image light from the screen is incident on the stop STO after multiple refractions and reflections of the second lens E2 and the first lens E1, and then enters the human eye. Specifically, the image light from the display screen passes through the second lens E2 and the quarter-wave plate QWP in sequence to reach the reflective polarizing element RP, is then reflected at the reflective polarizing element RP, and passes through the quarter-wave plate QWP and the second lens E2 again to reach the partial reflection layer BS, after which the light beam is reflected at the partial reflection layer BS and passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 in sequence, and is then incident on the stop STO, and then exits towards the human eye side. According to the visual optical system provided in the present application, the required optical path is folded in a combination of light reflection and refraction without affecting the imaging quality, effectively shortening the length of the visual optical system.

[0181] Example 10

[0182] Figure 17 A structure schematic diagram of a visual optical system according to Embodiment 10 of the present application is shown. As shown in Figure 17 the visual optical system includes a lens barrel P0, and a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, a partial reflection layer BS, and a screen arranged in sequence from the side away from the screen to the side close to the screen.

[0183] In this embodiment, the light-out surface S5 of the second lens E2 is a thin Fresnel surface.

[0184] In this embodiment, the visual optical system may further include a first support member P1 located between the first lens E1 and the second lens E2. The first support member P1 may at least partially contact the side of the second lens E2 away from the screen, for example, it may abut against the light-emitting surface S5 of the second lens E2 and at least partially contact the inner wall of the lens barrel P0; and include a first auxiliary support member P1b located on the side of the first lens E1 away from the screen. The first auxiliary support member P1b may at least partially contact the side of the first lens E1 away from the screen and the inner wall of the lens barrel P0.

[0185] Table 9 shows the basic parameters of the visual optical systems of Examples 9 and 10, where the units for radius of curvature and thickness / distance are millimeters (mm).

[0186]

[0187] Table 9

[0188] In Examples 9 and 10, the light-emitting surface S1 of the first lens E1, the light-emitting surface S5 of the second lens E2, and the light-incident surface S6 are all aspherical surfaces. The surface shape x of each aspherical lens can be defined by, but is not limited to, the above formula (1).

[0189] Table 10 lists the higher-order coefficients A4, A6, A8, and A6 that can be used for the aspherical surfaces S1, S5, and S6 in Examples 9 and 10. 10 A 12 A 14 A 16 A 18 and A 20 .

[0190] Face No. A4 A6 A8 A10 A12 S1 1.82E-06 3.30E-09 -9.06E-12 6.13E-15 0.00E+00 S5 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 3.80E-07 4.16E-10 0.00E+00 0.00E+00 0.00E+00 Face No. A14 A16 A18 A20 S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S5 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0191] Table 10

[0192] Figure 18A The on-axis chromatic aberration curves of the visual optical systems of Embodiments 9 and 10 are shown, which represent the deviation of the focal point of light of different wavelengths after passing through the lens. Figure 18B Astigmatism curves for the visual optical systems of Embodiments 9 and 10 are shown, representing meridional image plane curvature and sagittal image plane curvature. According to... Figure 18A and Figure 18B It can be seen that the visual optical systems given in Examples 9 and 10 can achieve good imaging quality.

[0193] The following Tables 11-1 and 11-2 respectively show the optical parameters of the visual optical system and the spacing of each optical element of Examples 1 to 10, such as the effective focal length F, the F number FNO, the half of the maximum field of view Semi-FOV, the focal length value of each lens group, and the related parameters of the first bearing and the lens barrel. The units of the distance and the focal length value are millimeters (mm).

[0194] Parameter / Example 1 2 3 4 5 Semi-FOV (°) 47.97 47.97 47.97 47.97 47.97 F 33.62 33.62 29.55 29.55 33.02 F1 115638.30 115638.30 68765.42 68765.42 3535.17 F2 159.72 159.72 121.05 121.05 147.13 FNO 8.41 8.41 7.39 7.39 6.60 d1bs 38.181 38.181 38.621 38.621 37.897 d1s 57.043 58.408 53.678 53.112 61.259 d1m 56.841 58.408 52.845 53.112 60.262 D1s 59.719 63.779 57.024 58.483 64.236 d0s 45.641 45.641 46.082 46.082 46.262 d0m 63.783 65.779 60.189 60.189 68.290 D0s 55.305 55.305 55.746 55.746 55.926 D0m 67.479 69.475 63.385 63.385 71.486 CP1 3.522 0.100 1.150 0.100 3.544 L 16.989 16.989 16.453 16.453 20.073 EP01 7.585 11.007 8.697 8.697 9.747

[0195] Table 11-1

[0196] Parameter / Example 6 7 8 9 10 Semi-FOV (°) 47.97 50.00 50.00 47.97 47.97 F 33.02 33.56 33.56 33.62 33.62 F1 3535.17 4378.59 4378.59 115638.30 115638.30 F2 147.13 152.43 152.43 159.72 159.72 FNO 6.60 8.39 8.39 8.46 8.46 d1bs 60.070 40.011 62.008 40.065 38.841 d1s 60.588 61.607 61.020 54.802 54.830 d1m 60.588 61.023 61.020 54.838 54.830 D1s 64.710 64.665 65.972 60.033 60.577 d0s 66.248 48.358 67.952 46.982 45.759 d0m 67.022 67.973 67.973 63.107 64.004 D0s 69.444 58.022 71.148 56.867 55.644 D0m 70.218 71.168 71.168 66.303 67.200 CP1 0.100 3.235 0.100 1.792 0.100 L 16.064 19.044 15.814 16.668 17.077 EP01 9.372 9.241 9.121 6.233 6.769

[0197] Table 11-2

[0198] In summary, in Examples 1 to 10, the visual optical system respectively satisfies the following conditional expressions shown in Table 12.

[0199]

[0200]

[0201] Table 12

[0202] The above description is merely preferred embodiments of the present application and the technical principles used. Those skilled in the art should understand that the scope of the application disclosed in the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or equivalent features without departing from the inventive concept. For example, the above features can be replaced with the technical features disclosed in the present application (but not limited to) having similar functions to form technical solutions.

Claims

1. A visual optical system, comprising a first lens group and a second lens group sequentially along the optical axis from the side furthest from the screen to the side closest to the screen, characterized in that, The first lens group includes a first lens, a reflective polarizing element, and a quarter-wave plate, wherein the reflective polarizing element and the quarter-wave plate are sequentially attached to the side of the first lens near the screen. The second lens group includes a second lens and a partial reflective layer, the partial reflective layer being attached to the side of the second lens near the screen. The number of lenses with optical power in the visual optical system is two; The side of the first lens away from the screen is convex, and the side closer to the screen is either flat or convex. The second lens has convex surfaces on both the side away from the screen and the side near the screen; The side of the first lens away from the screen or the side of the second lens away from the screen is a Fresnel surface; The visual optical system further includes a lens barrel and a first support member positioned on the screen side of the first lens, wherein the first support member is in at least partial contact with the screen side of the first lens or the screen-away side of the second lens; the first lens group, the second lens group, and the first support member are all housed inside the lens barrel. The inner diameters of the first support member on both the side away from the screen and the side near the screen are greater than 50mm, and the inner diameter d1m of the first support member on the side near the screen, the radius of curvature R3 of the second lens on the side away from the screen, and the radius of curvature R4 of the second lens on the side near the screen satisfy: -18.40≤d1m / (R3+R4)≤8.

36.

2. The visual optical system according to claim 1, wherein, The visual optical system further includes a first auxiliary support member, which is located on the side of the first lens away from the screen and at least partially in contact with the side of the first lens away from the screen, or located on the side of the second lens away from the screen and at least partially in contact with the side of the second lens away from the screen.

3. The visual optical system according to claim 1, wherein, The effective focal length F1 of the first lens group, the radius of curvature R1 of the side of the first lens away from the screen, the outer diameter D1s of the first support member away from the screen, and the inner diameter d1s of the first support member away from the screen satisfy: 1.13≤F1 / R1+D1s / d1s≤3.

13.

4. The visual optical system according to claim 1, wherein, The distance EP01 between the surface of the lens barrel away from the screen and the surface of the first support member away from the screen on the optical axis satisfies the following condition: 1.45≤EP01 / CT1≤2.

29.

5. The visual optical system according to claim 1, wherein, The outer diameter D1s of the first support member away from the screen, the effective focal length F1 of the first lens group, and the effective focal length F2 of the second lens group satisfy: 0.08mm≤D1s / (F1 / F2)≤6.75mm.

6. The visual optical system according to claim 1, wherein, The distance between the first lens group and the second lens group is less than 1.0 mm, and the maximum thickness CP1 of the first support member, the inner diameter d1m of the first support member near the screen side and the inner diameter d1s of the first support member away from the screen side satisfy: 0.10 mm ≤ CP1 / (d1m / d1s) ≤ 3.60 mm.

7. The visual optical system according to claim 1, wherein, The outer diameter D0m of the lens barrel near the screen, the outer diameter D0s of the lens barrel away from the screen, and the distance TD from the side of the first lens away from the screen to the side of the second lens near the screen on the optical axis satisfy: 6.57≤(D0m+D0s) / TD≤8.

09.

8. The visual optical system according to claim 2, wherein, The inner diameter d0s of the lens barrel away from the screen, the inner diameter d1bs of the first auxiliary support member away from the screen, and the aperture number Fno of the visual optical system satisfy: 7.28 ≤ d0s / d1bs Fno≤10.

14.

9. The visual optical system according to claim 1, wherein, The outer diameter D0m of the lens barrel near the screen and the inner diameter d0m of the lens barrel near the screen satisfy: 310.18mm 2 ≤π(D0m 2 -d0m 2 ≤392.61mm 2 , where π is the ratio of a circle's diameter to its circumference.

10. The visual optical system according to claim 1, wherein, The distance from the side of the second lens near the screen to the screen is less than 20.0 mm, and the inner diameter d0m of the lens barrel near the screen and the radius of curvature R4 of the second lens near the screen satisfy: 0.37≤|d0m / R4|≤0.

50.

11. The visual optical system according to claim 1, wherein, The maximum height L of the lens barrel, the distance EP01 from the side of the lens barrel away from the screen to the side of the first support member away from the screen on the optical axis, the maximum thickness CP1 of the first support member, and the center thickness CT2 of the second lens satisfy: 0.51≤(L-EP01-CP1) / CT2<1.

0.

12. The visual optical system according to any one of claims 1-11, wherein, The radius of curvature R2 of the first lens near the screen side, the radius of curvature R3 of the second lens away from the screen side, and the inner diameter d1s of the first support member away from the screen side satisfy: -37.87≤(R2+R3) / d1s≤-9.

06.

13. The visual optical system according to any one of claims 1-11, wherein, The effective focal length F of the visual optical system and the maximum height L of the lens barrel satisfy the following condition: 1.64 ≤ F / L ≤ 2.

12.

14. The visual optical system according to any one of claims 1-11, wherein, The fundamental curvature of the Fresnel surface is less than 10. -6 .

15. The visual optical system according to any one of claims 1-11, wherein, The maximum thickness of the first support member is greater than 0.2 mm, and the first support member is in at least partial contact with the inner wall of the lens barrel.

Images