Visual system and electronic apparatus

Abstract

The invention provides a visual system and electronic equipment, the visual system sequentially comprises a reflective polarizing element, a quarter-wave plate, a first lens, a second lens and a screen, the second side surface of the first lens is a convex surface; the second side surface of the second lens is a convex surface; the visual system further comprises a partial reflection element, and the partial reflection element is located on the second side face of the first lens or the second side face of the second lens. The screen is configured to be movable along the optical axis to approach or leave the second lens. The visual system satisfies: 1.46 < = (CT1 + CT2) / [Delta] L < = 4.05; f / delta L is more than 3.90 and less than 5.95; cT1 is the center thickness of the first lens, CT2 is the center thickness of the second lens, delta L is the distance of the screen moving along the optical axis when the visual system moves from the first state to the second state, and f is the effective focal length of the visual system. The visual system not only effectively compresses the axial size of the catadioptric framework, but also can guarantee the stable output of the focal power of the lens.

Description

Technical Field

[0001] This application relates to the field of optical components, and more specifically, to a visual system and electronic equipment. Background Technology

[0002] As virtual reality technology iterates towards lightweight and high-definition, the catadioptric optical path architecture has become the mainstream choice for consumer VR devices due to its compact size and clear imaging. However, existing catadioptric solutions mostly use fixed optical structures, which are difficult to adapt to the refractive error needs of different users. Wearers need to wear glasses, which not only reduces wearing comfort but also easily causes problems such as glare and parallax.

[0003] Meanwhile, traditional diopter adjustment schemes mostly rely on mechanically moving lens groups, which suffers from drawbacks such as complex structure, low adjustment precision, and susceptibility to assembly errors, thus limiting the portability and user experience of VR devices. Against this backdrop, there is an urgent need for a catadioptric optical solution that achieves diopter adaptation without external devices by adjusting the back focal distance from the screen to the last lens, in order to overcome existing technological bottlenecks. Summary of the Invention

[0004] This application provides a visual system comprising, sequentially from a first side to a second side along the optical axis: a reflective polarizing element, a quarter-wave plate, a first lens, a second lens, and a screen. The first lens has positive optical power, and its second side surface is convex. The second lens has either positive or negative optical power, and its second side surface is convex. The quarter-wave plate is attached to the first side surface of the first lens, and the reflective polarizing element is attached to the first side surface of the quarter-wave plate. The visual system further includes a partial reflective element located on the second side surface of either the first lens or the second lens. The screen is configured to move along the optical axis to approach or move away from the second lens. The visual system satisfies the following conditions: 1.46 ≤ (CT1 + CT2) / ΔL ≤ 4.05; 3.90 < f / ΔL < 5.95. Wherein, CT1 is the center thickness of the first lens, CT2 is the center thickness of the second lens, ΔL is the distance the screen moves along the optical axis from the first state to the second state, and f is the effective focal length of the visual system.

[0005] In one embodiment, the effective focal length f1 of the first lens, the center thickness CTR of the reflective polarizing element, the center thickness CTQ of the quarter-wave plate, and the center thickness CT1 of the first lens satisfy: 12.05≤f1 / (CTR+CTQ+CT1)≤31.20.

[0006] In one embodiment, the radius of curvature R2 of the second side surface of the first lens and the radius of curvature R3 of the first side surface of the second lens satisfy: -1.35 < R2 / |R3| < -0.30.

[0007] In one embodiment, the on-axis distance TD from the first side surface of the first lens to the second side surface of the second lens and the on-axis distance BFLm from the second side surface of the second lens to the screen in the first state satisfy: 0.70 < TD / BFLm < 3.50.

[0008] In one embodiment, the combined focal length f12 of the first lens and the second lens, and the distance ΔL by which the screen moves along the optical axis from the first state to the second state satisfy: 6.50≤f12 / ΔL≤15.98.

[0009] In one embodiment, the effective focal length f2 of the second lens and the radius of curvature R4 of the second side surface of the second lens satisfy: -2.10 < |f2| / R4 < -0.70.

[0010] In one embodiment, the effective focal length f of the visual system, the center thickness CT2 of the second lens, and the on-axis distance BFLn from the second side of the second lens to the screen in the second state satisfy: 2.05 < f / (CT2+BFLn) < 2.85.

[0011] In one embodiment, the combined focal length f12 of the first lens and the second lens, the Abbe number V1 of the first lens, and the Abbe number V2 of the second lens satisfy: 0.30mm < f12 / (V1+V2) < 1.95mm.

[0012] In one embodiment, the distance ΔL that the screen moves along the optical axis when the visual system moves from the first state to the second state, the refractive index N2 of the second lens, and the refractive index N1 of the first lens satisfy: 4.20mm≤ΔL×(N2 / N1)≤8.73mm.

[0013] In one embodiment, the axial distance BFLm from the second side surface of the second lens to the screen in the first state, the axial distance BFLn from the second side surface of the second lens to the screen in the second state, and the radius of curvature R4 of the second side surface of the second lens satisfy: -0.58≤(BFLm+BFLn) / R4≤-0.05.

[0014] In one embodiment, the air gap T12 between the second side of the first lens and the first side of the second lens on the optical axis and the entrance pupil diameter EPD of the visual system satisfy: 0.25≤T12 / EPD≤2.00.

[0015] In one embodiment, the axial distance TD between the first side surface of the first lens and the second side surface of the second lens, the center thickness CT1 of the first lens, and the center thickness CT2 of the second lens satisfy: 1.07≤TD / (CT1+CT2)≤1.50.

[0016] In one embodiment, the effective focal length f of the visual system and the on-axis distance BFLm from the second side surface of the second lens to the screen in the first state satisfy: 1.80 < f / BFLm < 4.20.

[0017] In one embodiment, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f of the visual system satisfy: 3.85 < |f1+f2| / f < 11.45.

[0018] This application also provides an electronic device, including the visual system provided in any embodiment of this application.

[0019] The visual system provided in this application embodiment, by constraining 1.46≤(CT1+CT2) / ΔL≤4.05 and 3.90<f / ΔL<5.95, can match the correlation characteristics between the lens group thickness ratio and the diopter adjustment range. Within the diopter adjustment range from the first state to the second state, the visual system can achieve clear imaging by controlling only a small movement of the screen. This effectively compresses the axial dimension of the catadioptric structure, meeting the design requirements of lightweight and portable VR devices, while ensuring stable output of lens optical power, reducing aberration fluctuations caused by screen movement, improving imaging clarity and field uniformity in all diopter states, and significantly optimizing the user wearing experience. Attached Figure Description

[0020] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments, taken in conjunction with the accompanying drawings. In the drawings:

[0021] Figure 1 This paper shows a schematic diagram of the visual system of Embodiment 1 provided in the present application in the first state; Figure 2 The modulation transfer function curve of the visual system in the first state according to Embodiment 1 of this application is shown; Figure 3 A schematic diagram of the visual system of Embodiment 1 provided in this application in the second state is shown; Figure 4 The modulation transfer function curve of the visual system in the second state according to Embodiment 1 of this application is shown; Figure 5 A schematic diagram of the visual system of Embodiment 2 provided in this application in the first state is shown; Figure 6 The modulation transfer function curve of the visual system in the first state according to Embodiment 2 of this application is shown; Figure 7 A schematic diagram of the visual system of Embodiment 2 provided in this application in the second state is shown; Figure 8 The modulation transfer function curve of the visual system in the second state according to Embodiment 2 of this application is shown; Figure 9 A schematic diagram of the visual system of Embodiment 3 provided in this application in the first state is shown; Figure 10 The modulation transfer function curve of the visual system in the first state according to Embodiment 3 of this application is shown; Figure 11 A schematic diagram of the visual system of Embodiment 3 provided in this application in the second state is shown; Figure 12 The modulation transfer function curve of the visual system in the second state according to Embodiment 3 of this application is shown; Figure 13 A schematic diagram of the visual system of Embodiment 4 provided in this application in the first state is shown; Figure 14 The modulation transfer function curve of the visual system in the first state according to Embodiment 4 of this application is shown; Figure 15 A schematic diagram of the visual system of Embodiment 4 provided in this application in the second state is shown; and Figure 16 The modulation transfer function curve of the visual system in the second state of Embodiment 4 provided in this application is shown. Detailed Implementation

[0022] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0023] It should be noted that in this specification, the terms "first," "second," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of this application, the first lens discussed below may also be referred to as the second lens, and the second lens may also be referred to as the first lens.

[0024] In the accompanying 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 illustrated by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to those shown in the drawings. The drawings are for illustrative purposes only and are not strictly to scale.

[0025] In this paper, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the location of the convexity is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the location of the concaveness is not defined, it means that the lens surface is concave at least in the paraxial region.

[0026] It should also be understood that the terms "comprising," "including," "having," "containing," and / or "comprising," when used in this specification, indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to an example or illustration.

[0027] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formalized sense, unless expressly so specified herein.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0029] The features, principles and other aspects of this application are described in detail below.

[0030] This application provides a visual system. The visual system, along the optical axis from a first side to a second side, sequentially includes: a reflective polarizing element, a quarter-wave plate, a first lens, a second lens, and a screen. The first lens has positive optical power, and its second side is convex; the second lens has either positive or negative optical power, and its second side is convex; the quarter-wave plate is attached to the first side of the first lens, and the reflective polarizing element is attached to the first side of the quarter-wave plate; the visual system also includes a partial reflective element located on the second side of the first lens or on the second side of the second lens; the screen is configured to move along the optical axis to approach or move away from the second lens, and the visual system satisfies: 1.46 ≤ (CT1 + CT2) / ΔL ≤ 4.05; 3.90 < f / ΔL < 5.95; CT1 is the center thickness of the first lens, CT2 is the center thickness of the second lens, ΔL is the distance the screen moves along the optical axis from the first state to the second state, and f is the effective focal length of the visual system.

[0031] The visual system provided in this application embodiment, by constraining 1.46≤(CT1+CT2) / ΔL≤4.05 and 3.90<f / ΔL<5.95, can match the correlation characteristics between the lens group thickness ratio and the diopter adjustment range. Within the diopter adjustment range from the first state to the second state, the visual system can achieve clear imaging by controlling only a small movement of the screen. This effectively compresses the axial dimension of the catadioptric structure, meeting the design requirements of lightweight and portable VR devices, while ensuring stable output of lens optical power, reducing aberration fluctuations caused by screen movement, improving imaging clarity and field uniformity in full diopter states, and significantly optimizing the user wearing experience.

[0032] In an exemplary embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display side. The visual system can be used, for example, in VR devices. The display side includes a screen (image surface), such as an LCD screen or an OLED screen, and is the "starting point" of the light path. Light emitted from the screen passes through the visual system and enters the human eye, thereby allowing the viewer to see the virtual image.

[0033] In the embodiments provided in this application, for example, a quarter-wave plate is at least partially attached to the first side surface of a first lens, and a reflective polarizing element is at least partially attached to the first side surface of the quarter-wave plate. By utilizing the reflective polarizing element, the quarter-wave plate, and the partially reflective element, optical path refraction can be achieved, effectively shortening the overall length of the visual system, reducing its volume and weight, and achieving a lighter visual system. The quarter-wave plate is used to change the polarization state of specific polarized light, for example, converting circularly polarized light into linearly polarized light, or vice versa. The reflective polarizing element can reflect light in a predetermined direction (e.g., S-direction linearly polarized light) and transmit light in a direction orthogonal to the predetermined direction (e.g., P-direction linearly polarized light).

[0034] For example, a partial reflective element may be located on the second side of the first lens and attached to it; or it may be located on the second side of the second lens and attached to it. The partial reflective element can provide both partial transmission and partial reflection of light. By placing a partial reflective element on the second side of the second lens, combined with a reflective polarizing element and a quarter-wave plate, light can be refracted multiple times, effectively reducing the overall length of the visual system.

[0035] In an exemplary embodiment, the visual system of this application may include at least one aperture stop. The aperture stop can constrain the optical path and control the light intensity. The aperture stop can be disposed at an appropriate location in the visual system; for example, the aperture stop can be located between a first side (e.g., the human eye side) and a reflective polarizing element.

[0036] In an exemplary embodiment, the positions of the first lens and the second lens on the optical axis are fixed. The screen can move relative to the second lens along the optical axis, meaning the distance between the screen and the second lens on the optical axis is adjustable. By moving the screen, the visual system can switch between a first state and a second state, thereby adjusting the diopter of the visual system to meet the usage needs of users with different diopter levels, such as users with diopter levels from +2D to -5D.

[0037] When the visual system is in its first state, its refractive power is +2D, suitable for users with a refractive power of +2D. When the visual system is in its second state, its refractive power is -5D, suitable for users with a refractive power of -5D. A negative sign for refractive power indicates that the user is myopic; a positive sign indicates that the user is hyperopic. The specific numerical value of refractive power represents the user's refractive error. For example, a refractive power of +1D indicates that the user's hyperopia is approximately 100 degrees, and a refractive power of -1D indicates that the user's myopia is approximately 100 degrees.

[0038] It should be understood that the visual system having two states (e.g., a first state and a second state) is merely exemplary. The visual system may also have at least one other state besides the first and second states. When the visual system is in other states, the refractive power of the visual system is between +2D and -5D. This application does not impose a specific limitation on the number of states that the visual system may have.

[0039] In an exemplary embodiment, the virtual image distance of the visual system differs in the first state and the second state. The virtual image distance can be, for example, the axial distance from the virtual image formed by the image light from the second side at a predetermined position to the aperture. Here, VID = 1000 / diopter.

[0040] In an exemplary embodiment, the effective focal length f1 of the first lens, the center thickness CTR of the reflective polarizing element, the center thickness CTQ of the quarter-wave plate, and the center thickness CT1 of the first lens satisfy: 12.05 ≤ f1 / (CTR+CTQ+CT1) ≤ 31.20. This embodiment, by reasonably controlling this conditional range, can optimize the thickness ratio of the front group optical elements, ensure the efficient utilization of the first lens's optical power, and improve the optical path folding efficiency and imaging quality of the visual system.

[0041] In an exemplary embodiment, the radius of curvature R2 of the second side surface of the first lens and the radius of curvature R3 of the first side surface of the second lens satisfy: -1.35 < R2 / |R3| < -0.30. This embodiment reasonably controls the range of this conditional expression, which can optimize the surface matching degree of the first and second lenses, reduce the spherical aberration and chromatic aberration of the system, and improve the imaging sharpness and field uniformity of the visual system.

[0042] In an exemplary embodiment, the axial distance TD between the first side surface of the first lens and the second side surface of the second lens, and the axial distance BFLm between the second side surface of the second lens and the screen in the first state, satisfy: 0.70 < TD / BFLm < 3.50. This embodiment reasonably controls the range of this conditional expression, which can optimize the axial dimension ratio of the visual system, balance the refractive adjustment range and structural compactness, and improve the space utilization of VR devices.

[0043] In an exemplary embodiment, the combined focal length f12 of the first and second lenses and the distance ΔL that the screen moves along the optical axis from the first state to the second state satisfy: 6.50 ≤ f12 / ΔL ≤ 15.98. This embodiment reasonably controls this conditional range, which can optimize the matching degree between the optical power of the lens group and the refractive adjustment range, and ensure imaging stability under a large refractive adjustment range.

[0044] In an exemplary embodiment, the effective focal length f2 of the second lens and the radius of curvature R4 of the second side surface of the second lens satisfy: -2.10 < |f2| / R4 < -0.70. This embodiment reasonably controls the range of this condition, which is beneficial for adjusting the incident angle when light converges to the reflective polarizing element after passing through the second lens, and reducing the loss of light during the reflection process.

[0045] In an exemplary embodiment, the effective focal length f of the visual system, the center thickness CT2 of the second lens, and the axial distance BFLn from the second side of the second lens to the screen in the second state satisfy: 2.05 < f / (CT2 + BFLn) < 2.85. This embodiment reasonably controls the range of this conditional expression, which can optimize the system's axial dimensions and optical power ratio, ensure imaging clarity in -5D state, and take into account the optical stability throughout the refractive adjustment range.

[0046] In an exemplary embodiment, the combined focal length f12 of the first lens and the second lens, the Abbe number V1 of the first lens, and the Abbe number V2 of the second lens satisfy: 0.30mm < f12 / (V1+V2) < 1.95mm. This embodiment reasonably controls this conditional range, which can optimize the chromatic aberration characteristics matching of the lens group, effectively suppress system chromatic aberration, and improve the imaging color consistency of the entire field of view of the visual system.

[0047] In an exemplary embodiment, the distance ΔL the screen moves along the optical axis, the refractive index N2 of the second lens, and the refractive index N1 of the first lens satisfy the condition: 4.20mm ≤ ΔL × (N2 / N1) ≤ 8.73mm. This embodiment reasonably controls this conditional range, optimizing the compatibility between the refractive indices of the first and second lenses and the refractive adjustment range, ensuring optical path stability and imaging clarity under different states.

[0048] In an exemplary embodiment, the axial distance BFLm from the second side surface of the second lens to the screen in the first state, the axial distance BFLn from the second side surface of the second lens to the screen in the second state, and the radius of curvature R4 of the second side surface of the second lens satisfy: -0.58≤(BFLm+BFLn) / R4≤-0.05. This embodiment reasonably controls this conditional range, which can optimize the adaptation of the screen position and the surface shape of the second lens throughout the refractive adjustment, suppress aberration fluctuations, and ensure imaging consistency under different refractive power states.

[0049] In an exemplary embodiment, the air gap T12 between the second side surface of the first lens and the first side surface of the second lens on the optical axis, and the entrance pupil diameter EPD of the visual system, satisfy: 0.25 ≤ T12 / EPD ≤ 2.00. This embodiment reasonably controls this conditional range, which can optimize the matching degree between the system entrance pupil and the lens group, improve the light transmission efficiency of the entire field of view, suppress off-axis aberrations, and ensure the uniformity of imaging.

[0050] In an exemplary embodiment, the axial distance TD between the first side surface of the first lens and the second side surface of the second lens, the center thickness CT1 of the first lens, and the center thickness CT2 of the second lens satisfy: 1.07 ≤ TD / (CT1+CT2) ≤ 1.50. This embodiment reasonably controls the range of this conditional expression, thereby controlling the axial compactness of the visual system, optimizing the spatial arrangement of the lens group, and avoiding the impact of structural redundancy on the flexibility of refractive adjustment.

[0051] In an exemplary embodiment, the effective focal length f of the visual system and the on-axis distance BFLm from the second side surface of the second lens to the screen in the first state satisfy: 1.80 < f / BFLm < 4.20. This embodiment reasonably controls the range of this conditional expression, which can optimize the optical path structure ratio in the +2D state and ensure the imaging clarity and field uniformity in this refractive state.

[0052] In an exemplary embodiment, the effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f of the visual system satisfy: 3.85 < |f1+f2| / f < 11.45. This embodiment reasonably controls the range of this conditional expression, which can optimize the optical power distribution of the first and second lenses, improve the refractive accommodation response speed of the system, and ensure imaging stability across the entire accommodation range.

[0053] The following description, with reference to the accompanying drawings, further illustrates specific surface shapes and parameters of the visual system applicable to the above embodiments. It should be noted that any of the examples in Embodiments 1 to 4 described below are applicable to all embodiments of this application.

[0054] Example 1 like Figures 1 to 4 As shown, the visual system of Embodiment 1 is described. Figure 1 A schematic diagram of the visual system of Embodiment 1 in its first state (e.g., +2D state) is shown. Figure 2 The modulation transfer function curve of the visual system of Embodiment 1 in a first state (e.g., +2D state) is shown. Figure 3 A schematic diagram of the visual system of Embodiment 1 in a second state (e.g., -5D state) is shown. Figure 4 The modulation transfer function curve of the visual system of Embodiment 1 is shown when it is in the second state (e.g., -5D state).

[0055] like Figure 1 and Figure 3As shown, the visual system according to an exemplary embodiment of this application includes a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, and a screen IMG. The reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the screen IMG are arranged sequentially from the first side to the second side along the optical axis.

[0056] A quarter-wave plate (QWP) is attached to the first side of the first lens (E1), and a reflective polarizing element (RP) is attached to the first side of the quarter-wave plate (QWP).

[0057] The visual system also includes a partial reflective element BS. In Embodiment 1, this partial reflective element BS is located on the second side of the first lens E1.

[0058] In practical use, the visual system according to the exemplary embodiments of this application can be used as a VR lens, where the first side corresponds to the human eye side and the second side corresponds to the display side.

[0059] In Embodiment 1 of this application, the light beam emitted from the screen IMG passes through the second lens E2 and the first lens E1, and then enters the reflective polarizing element RP via the quarter-wave plate QWP. It is reflected at the reflective polarizing element RP and passes again through the quarter-wave plate QWP and the first lens E1 to reach the partial reflective element BS. Afterward, the light beam is reflected again at the partial reflective element BS and sequentially passes through the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP towards the first side (e.g., ...). Figure 1 It exits from the aperture STO and eventually enters the human eye.

[0060] In one embodiment of this application, the first lens E1 has positive optical power, the first side surface S1 of the first lens E1 is a plane, and the second side surface S2 of the first lens E1 is a convex surface; the second lens E2 has positive optical power, the first side surface S3 of the second lens E2 is a concave surface, and the second side surface S4 of the second lens E2 is a convex surface; the screen IMG is configured to move along the optical axis to approach or move away from the second lens.

[0061] The basic parameters of the visual system in Embodiment 1 are shown in Table 1 (unit: mm). In Table 1, S1 represents the first side surface of the first lens E1, S2 represents the second side surface of the first lens E1, and the second side surface S2 is attached with a partial reflective element BS. Therefore, S2 can also be regarded as the surface of the partial reflective element BS. S3 represents the first side surface of the second lens E2, S4 represents the second side surface of the second lens E2, and S5 represents the surface where the screen is located.

[0062] Table 1

[0063] In this embodiment, the second side surface S2 of the first lens, the first side surface S3 of the second lens, and the second side surface S4 of the second lens are all aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula: .

[0064] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the aspherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 1 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients. Table 2 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror S2, S3 and S4 in this embodiment.

[0065] Table 2

[0066] In this embodiment, the visual system has a first state (e.g., Figure 1 ) and the second state (e.g., Figure 3 The virtual image distance of the visual system is taken as D1, and the distance between the second side of the second lens and the screen is taken as D2. D1 and D2 are variables that can change with the state of the visual system. Table 3 shows the values ​​of D1 and D2 in different states of the visual system in Embodiment 1.

[0067] Table 3

[0068] Figure 2 The modulation transfer function curve of the visual system in Embodiment 1 when it is in the first state is shown. Figure 4 The modulation transfer function curve of the visual system in Embodiment 1 when it is in the second state is shown. From Figure 2 and Figure 4 As can be seen, the visual system given in Example 1 can achieve good imaging quality in both the first and second states.

[0069] Example 2 like Figures 5 to 8 As shown, the visual system of Embodiment 2 is described. Figure 5 A schematic diagram of the visual system of Embodiment 2 in the first state (e.g., +2D state) is shown. Figure 6The modulation transfer function curve of the visual system in Embodiment 2 in the first state (e.g., +2D state) is shown. Figure 7 A schematic diagram of the visual system of Embodiment 2 in the second state (e.g., -5D state) is shown. Figure 8 The modulation transfer function curve of the visual system of Embodiment 2 is shown in the second state (e.g., -5D state).

[0070] like Figure 5 and Figure 7 As shown, the visual system according to an exemplary embodiment of this application includes a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, and a screen IMG. The reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the screen IMG are arranged sequentially from the first side to the second side along the optical axis.

[0071] A quarter-wave plate (QWP) is attached to the first side of the first lens (E1), and a reflective polarizing element (RP) is attached to the first side of the quarter-wave plate (QWP).

[0072] The visual system also includes a partial reflective element BS. In Embodiment 2, this partial reflective element BS is located on the second side of the first lens E1.

[0073] In practical use, the visual system according to the exemplary embodiments of this application can be used as a VR lens, where the first side corresponds to the human eye side and the second side corresponds to the display side.

[0074] In the second embodiment of this application, the light beam emitted from the screen IMG passes through the second lens E2 and the first lens E1, and then enters the reflective polarizing element RP via the quarter-wave plate QWP. It is reflected at the reflective polarizing element RP and passes through the quarter-wave plate QWP and the first lens E1 again to reach the partial reflective element BS. Afterward, the light beam is reflected again at the partial reflective element BS and sequentially passes through the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP towards the first side (e.g., ...). Figure 5 and Figure 7 It exits from the aperture STO and eventually enters the human eye.

[0075] In the second embodiment of this application, the first lens E1 has positive optical power, its first side surface S1 is concave, and its second side surface S2 is convex; the second lens E2 has positive optical power, its first side surface S3 is convex, and its second side surface S4 is convex; the screen IMG is configured to move along the optical axis to approach or move away from the second lens.

[0076] The basic parameters of the visual system in Embodiment 2 are shown in Table 4 (unit: mm). In Table 4, S1 represents the first side surface of the first lens E1, S2 represents the second side surface of the first lens E1, and the second side surface S2 is attached with a partial reflective element BS. Therefore, S2 can also be regarded as the surface of the partial reflective element BS. S3 represents the first side surface of the second lens E2, S4 represents the second side surface of the second lens E2, and S5 represents the surface where the screen is located.

[0077] Table 4

[0078] In this embodiment, the first side surface S1 of the first lens, the second side surface S2 of the first lens, the first side surface S3 of the second lens, and the second side surface S4 of the second lens are all aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula: .

[0079] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the aspherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 4 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients. Table 5 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror S1, S2, S3 and S4 in this embodiment.

[0080] Table 5

[0081] In this embodiment, the visual system has a first state (e.g., Figure 5 ) and the second state (e.g., Figure 7 The virtual image distance of the visual system is taken as D1, and the distance between the second side of the second lens and the screen is taken as D2. D1 and D2 are variables that can change with the state of the visual system. Table 6 shows the values ​​of D1 and D2 in different states of the visual system in Embodiment 2.

[0082] Table 6

[0083] Figure 6 The modulation transfer function curve of the visual system in Embodiment 2 when it is in the first state is shown. Figure 8The modulation transfer function curve of the visual system in Embodiment 2 when it is in the second state is shown. From Figure 6 and Figure 8 As can be seen, the visual system given in Embodiment 2 can achieve good imaging quality in both the first and second states.

[0084] Example 3 like Figures 9 to 12 As shown, the visual system of Embodiment 3 is described. Figure 9 A schematic diagram of the visual system of Embodiment 3 in the first state (e.g., +2D state) is shown. Figure 10 The modulation transfer function curve of the visual system in Embodiment 3 in the first state (e.g., +2D state) is shown. Figure 11 A schematic diagram of the visual system of Embodiment 3 in the second state (e.g., -5D state) is shown. Figure 12 The modulation transfer function curve of the visual system of Embodiment 3 is shown in the second state (e.g., -5D state).

[0085] like Figure 9 and Figure 11 As shown, the visual system according to an exemplary embodiment of this application includes a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, and a screen IMG. The reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the screen IMG are arranged sequentially from the first side to the second side along the optical axis.

[0086] A quarter-wave plate (QWP) is attached to the first side of the first lens (E1), and a reflective polarizing element (RP) is attached to the first side of the quarter-wave plate (QWP).

[0087] The visual system also includes a partial reflective element BS. In Embodiment 3, this partial reflective element BS is located on the second side of the second lens E2.

[0088] In practical use, the visual system according to the exemplary embodiments of this application can be used as a VR lens, where the first side corresponds to the human eye side and the second side corresponds to the display side.

[0089] In Embodiment 3 of this application, the light beam emitted from the screen IMG passes through the second lens E2 and the first lens E1, and then enters the reflective polarizing element RP via the quarter-wave plate QWP. It is reflected at the reflective polarizing element RP and passes again through the quarter-wave plate QWP, the first lens E1, and the second lens E2 to reach the partial reflective element BS. Afterward, the light beam is reflected again at the partial reflective element BS and sequentially passes through the second lens E2, the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP towards the first side (e.g., ...). Figure 9 and Figure 11 It exits from the aperture STO and eventually enters the human eye.

[0090] In Embodiment 3 of this application, the first lens E1 has positive optical power, its first side surface S1 is a plane, and its second side surface S2 is a convex surface; the second lens E2 has negative optical power, its first side surface S3 is a concave surface, and its second side surface S4 is a convex surface; the screen IMG is configured to move along the optical axis to approach or move away from the second lens.

[0091] The basic parameters of the visual system in Embodiment 3 are shown in Table 7 (unit: mm). In Table 7, S1 represents the first side surface of the first lens E1, S2 represents the second side surface of the first lens E1, S3 represents the first side surface of the second lens E2, S4 represents the second side surface of the second lens E2, and S5 is the surface where the screen is located. A partial reflective element BS is attached to the second side surface S4 of the second lens E2; therefore, S4 can also be considered as the surface of the partial reflective element BS.

[0092] Table 7

[0093] In this embodiment, the second side surface S2 of the first lens, the first side surface S3 of the second lens, and the second side surface S4 of the second lens are all aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula: .

[0094] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the aspherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 7 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients. Table 8 below shows the higher-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror S2, S3 and S4 in this embodiment.

[0095] Table 8

[0096] In this embodiment, the visual system has a first state (e.g., Figure 9 ) and the second state (e.g., Figure 11The virtual image distance of the visual system is taken as D1, and the distance between the second side of the second lens and the screen is taken as D2. D1 and D2 are variables that can change with the state of the visual system. Table 9 shows the values ​​of D1 and D2 in different states of the visual system in Embodiment 3.

[0097] Table 9

[0098] Figure 10 The modulation transfer function curve of the visual system in Embodiment 3 when it is in the first state is shown. Figure 12 The modulation transfer function curve of the visual system in Embodiment 3 when it is in the second state is shown. From Figure 10 and Figure 12 As can be seen, the visual system given in Embodiment 3 can achieve good imaging quality in both the first and second states.

[0099] Example 4 like Figures 13 to 16 As shown, the visual system of Embodiment 4 is described. Figure 13 A schematic diagram of the visual system of Embodiment 4 in its first state (e.g., +2D state) is shown. Figure 14 The modulation transfer function curve of the visual system in Embodiment 4 is shown in the first state (e.g., +2D state). Figure 15 A schematic diagram of the visual system of Embodiment 4 in the second state (e.g., -5D state) is shown. Figure 16 The modulation transfer function curve of the visual system of Embodiment 4 is shown in the second state (e.g., -5D state).

[0100] like Figure 13 and Figure 15 As shown, the visual system according to an exemplary embodiment of this application includes a reflective polarizing element RP, a quarter-wave plate QWP, a first lens E1, a second lens E2, and a screen IMG. The reflective polarizing element RP, the quarter-wave plate QWP, the first lens E1, the second lens E2, and the screen IMG are arranged sequentially from the first side to the second side along the optical axis.

[0101] A quarter-wave plate (QWP) is attached to the first side of the first lens (E1), and a reflective polarizing element (RP) is attached to the first side of the quarter-wave plate (QWP).

[0102] The visual system also includes a partial reflective element BS. In embodiment four, the partial reflective element BS is located on the second side of the second lens E2.

[0103] In practical use, the visual system according to the exemplary embodiments of this application can be used as a VR lens, where the first side corresponds to the human eye side and the second side corresponds to the display side.

[0104] In Embodiment 4 of this application, the light beam emitted from the screen IMG passes through the second lens E2 and the first lens E1, and then enters the reflective polarizing element RP via the quarter-wave plate QWP. It is reflected at the reflective polarizing element RP and passes again through the quarter-wave plate QWP, the first lens E1, and the second lens E2 to reach the partial reflective element BS. Afterward, the light beam is reflected again at the partial reflective element BS and sequentially passes through the second lens E2, the first lens E1, the quarter-wave plate QWP, and the reflective polarizing element RP towards the first side (e.g., ...). Figure 13 and Figure 15 It exits from the aperture STO and eventually enters the human eye.

[0105] In Embodiment 4 of this application, the first lens E1 has positive optical power, its first side surface S1 is concave, and its second side surface S2 is convex; the second lens E2 has negative optical power, its first side surface S3 is concave, and its second side surface S4 is convex; the screen IMG is configured to move along the optical axis to approach or move away from the second lens.

[0106] The basic parameters of the visual system in Embodiment 4 are shown in Table 10 (unit: mm). In Table 10, S1 represents the first side surface of the first lens E1, S2 represents the second side surface of the first lens E1, S3 represents the first side surface of the second lens E2, S4 represents the second side surface of the second lens E2, and S5 is the surface where the screen is located. A partial reflective element BS is attached to the second side surface S4 of the second lens E2; therefore, S4 can also be considered as the surface of the partial reflective element BS.

[0107] Table 10

[0108] In this embodiment, the second side surface S2 of the first lens, the first side surface S3 of the second lens, and the second side surface S4 of the second lens are all aspherical surfaces. The surface shape of each aspherical lens can be defined using, but is not limited to, the following aspherical formula: .

[0109] in, For an aspherical surface along the optical axis at a height of h When the position is such that the distance from the vertex of the aspherical surface is the sag; c For the paraxial curvature of an aspherical surface, c =1 / R (i.e., paraxial curvature) c (The reciprocal of the radius of curvature R in Table 10 above). k The conic coefficient; Ai Is it an aspherical first i -th order correction coefficients. Table 11 below gives the higher order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 that can be used for each aspherical mirror S2, S3 and S4 in this embodiment.

[0110] Table 11

[0111] In this embodiment, the visual system has a first state (e.g., Figure 13 ) and the second state (e.g., Figure 15 The virtual image distance of the visual system is taken as D1, and the distance between the second side of the second lens and the screen is taken as D2. D1 and D2 are variables that can change with the state of the visual system. Table 12 shows the values ​​of D1 and D2 in different states of the visual system in Embodiment 4.

[0112] Table 12

[0113] Figure 14 The modulation transfer function curve of the visual system in Embodiment 4 when it is in the first state is shown. Figure 16 The modulation transfer function curve of the visual system in Embodiment 4 when it is in the second state is shown. From Figure 14 and Figure 16 As can be seen, the visual system given in Example 4 can achieve good imaging quality in both the first and second states.

[0114] The optical parameters of the visual systems in Examples 1, 2, 3, and 4 are shown in Table 13 (unit: mm). The conditional expressions satisfied by the visual systems in Examples 1, 2, 3, and 4 are shown in Table 14.

[0115] Table 13

[0116] Table 14

[0117] The embodiments of this application achieve a catadioptric optical solution without external diopter adaptation by adjusting the back focal distance from the screen to the last lens, thereby overcoming the bottleneck of the prior art.

[0118] Furthermore, this application also provides an electronic device that includes the visual system provided in any embodiment of this application. This electronic device is, for example, a VR device, which may include the visual system provided in any of the above embodiments, with the first side being the human eye side and the second side being the display side.

[0119] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of protection involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the concept of this application. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A vision system comprising, in order along an optical axis direction from a first side to a second side: A reflective polarizing element, a quarter wave plate, a first lens, a second lens, and a screen, characterized in that the first lens has positive refractive power, and a second side surface of the first lens is convex; the second lens has positive refractive power or negative refractive power, and a second side surface of the second lens is convex; the quarter wave plate is attached to a first side surface of the first lens, and the reflective polarizing element is attached to a first side surface of the quarter wave plate; the visual system further comprises a partial reflection element, which is located on the second side surface of the first lens or on the second side surface of the second lens; the screen is configured to be movable along the optical axis to approach or move away from the second lens, wherein the visual system satisfies: 1.46≤(CT1+CT2) / ΔL≤4.05; 3.90 wherein CT1 is the center thickness of the first lens, CT2 is the center thickness of the second lens, ΔL is the distance along the optical axis by which the screen moves in the visual system from a first state to a second state, and f is the effective focal length of the visual system.

2. The vision system of claim 1, wherein, The effective focal length f1 of the first lens, the center thickness CTR of the reflective polarizing element, the center thickness CTQ of the quarter wave plate, and the center thickness CT1 of the first lens satisfy: 12.05≤f1 / (CTR+CTQ+CT1)≤31.

20.

3. The vision system of claim 1, wherein, The curvature radius R2 of the second side surface of the first lens and the curvature radius R3 of the first side surface of the second lens satisfy: -1.35 4. The vision system of claim 1, wherein, The on-axis distance TD from the first side surface of the first lens to the second side surface of the second lens and the on-axis distance BFLm from the second side surface of the second lens to the screen in the first state satisfy: 0.70 5. The vision system of claim 1, wherein, The combined focal length f12 of the first lens and the second lens and the distance ΔL along the optical axis by which the screen moves in the visual system from the first state to the second state satisfy: 6.50≤f12 / ΔL≤15.

98.

6. The vision system of claim 1, wherein, The effective focal length f2 of the second lens and the curvature radius R4 of the second side surface of the second lens satisfy: -2.10 7. The vision system of claim 1, wherein, The effective focal length f of the visual system, the center thickness CT2 of the second lens, and the on-axis distance BFLn from the second side surface of the second lens to the screen in the second state satisfy: 2.05 8. The vision system of claim 1, wherein, The combined focal length f12 of the first lens and the second lens, the Abbe number V1 of the first lens, and the Abbe number V2 of the second lens satisfy: 0.30mm 9. The vision system of claim 1, wherein, The distance ΔL that the screen moves along the optical axis, the refractive index N2 of the second lens, and the refractive index N1 of the first lens satisfy 4.20 mm ≤ ΔL × (N2 / N1) ≤ 8.73 mm when the visual system moves from the first state to the second state.

10. The vision system of claim 1, wherein, The on-axis distance BFLm from the second side surface of the second lens to the screen in the first state, the on-axis distance BFLn from the second side surface of the second lens to the screen in the second state, and the radius of curvature R4 of the second side surface of the second lens satisfy -0.58 ≤ (BFLm + BFLn) / R4 ≤ -0.

05.

11. The vision system of claim 1, wherein, The air separation T12 on the optical axis from the first side surface of the first lens to the second side surface of the second lens, and the entrance pupil diameter EPD of the visual system satisfy 0.25 ≤ T12 / EPD ≤ 2.

00.

12. The vision system of claim 1, wherein, The on-axis distance TD from the first side surface of the first lens to the second side surface of the second lens, the central thickness CT1 of the first lens, and the central thickness CT2 of the second lens satisfy 1.07 ≤ TD / (CT1 + CT2) ≤ 1.

50.

13. The vision system of claim 1, wherein, The effective focal length f of the visual system, and the on-axis distance BFLm from the second side surface of the second lens to the screen in the first state satisfy 1.80 < f / BFLm < 4.

20.

14. The vision system of claim 1, wherein, The effective focal length f1 of the first lens, the effective focal length f2 of the second lens, and the effective focal length f of the visual system satisfy 3.85 < |f1 + f2| / f < 11.

45.

15. An electronic device, comprising: A visual system comprising the visual system according to any one of claims 1-14. A visual system comprising the visual system according to any one of claims 1-14.

Images