Visual system

Abstract

The application provides a visual system, comprising a lens barrel and a lens group in the lens barrel; the lens group comprises, in sequence from a first side to a second side: a first lens, the first side of which is a convex surface; a second lens, the first side of which is a flat surface and the second side of which is a convex surface; and a third lens, the first side of which is a concave surface and the second side of which is a convex surface, and the three lenses all have positive focal lengths; a partial reflection element is arranged between the second lens and the third lens, a first quarter-wave plate is attached to the first side of the second lens, a reflective polarizing element is attached to the first side of the first quarter-wave plate, an image surface is attached to a polarizing plate, a second quarter-wave plate is attached to the first side of the polarizing plate, and a first spacing element is arranged on the second side of the first lens; and the following conditions are met: 5.90 < f23 / (CT2+CT3) < 8.90; 4.40 < d0min / CT1 < 4.85; and 0.15 < T12 / (D1s-d1s) < 0.85.

Description

Technical Field

[0001] This application relates to the field of optical device technology, and in particular to a visual system. Background Technology

[0002] VR / AR optical modules are a crucial component of virtual reality and augmented reality technologies. Their development has improved user experience and product quality, and is continuously driving progress across the entire industry.

[0003] Existing VR / AR optical modules employ a folding-back architecture, which effectively shortens the overall physical length of the system by folding the optical path. However, the folding optical path in the folding-back architecture requires the optical path to undergo at least two reflections, which amplifies the divergence angle of stray light in the optical system. At the lens closest to the aperture stop, the height of the light path changes significantly during propagation. Stray light offset from the lens edge is prone to be reflected on the inner wall of the lens barrel and enters the actual image, interfering with the normal image. Summary of the Invention

[0004] This application provides a visual system comprising a lens barrel and a lens assembly assembled within the lens barrel; the lens assembly, from a first side to a second side, sequentially comprises: a first lens with positive optical power, the first side of which is convex; a second lens with positive optical power, the first side of which is planar and the second side of which is convex; and a third lens with positive optical power, the first side of which is concave and the second side of which is convex; a partial reflective element is disposed between the second lens and the third lens; a first quarter-wave plate is attached to the first side of the second lens; a reflective polarizing element is attached to the first side of the first quarter-wave plate; a polarizer is attached to the image surface of the visual system; and a second quarter-wave plate is attached to the first side of the polarizer. A half-wave plate, wherein a first spacer element is provided on the second side of the first lens; the visual system satisfies: 5.90 < f23 / (CT2+CT3) < 8.90; 4.40 < d0min / CT1 < 4.85 and 0.15 < T12 / (D1s-d1s) < 0.85; wherein f23 is the combined focal length of the second lens and the third lens, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, d0min is the minimum inner diameter of the lens barrel, CT1 is the center thickness of the first lens, T12 is the axial distance from the second side of the first lens to the first side of the second lens, D1s is the outer diameter of the first side of the first spacer element, and d1s is the inner diameter of the first side of the first spacer element.

[0005] In some embodiments of this application, the visual system further satisfies: 1.16≤f1 / (d0s+D0s)≤1.65, where f1 is the effective focal length of the first lens, d0s is the inner diameter of the first side of the lens barrel, and D0s is the outer diameter of the first side of the lens barrel.

[0006] In some embodiments of this application, the visual system further satisfies: 9.00 < d0m / CT3 < 12.80, where d0m is the inner diameter of the second side of the lens barrel and CT3 is the center thickness of the third lens.

[0007] In some embodiments of this application, the visual system further satisfies: 2.45 < TD / EP01 < 3.45, where TD is the axial distance from the first side surface of the first lens to the second side surface of the third lens, and EP01 is the distance along the optical axis from the first side surface of the lens barrel to the first side surface of the first spacer element.

[0008] In some embodiments of this application, the visual system further satisfies: 1.75 < L / (EP01+CP1) < 3.35, where L is the maximum height of the lens barrel, EP01 is the distance from the first side of the lens barrel to the first side of the first spacer element along the optical axis, and CP1 is the maximum thickness of the first spacer element.

[0009] In some embodiments of this application, the visual system further satisfies: 3.25 < d1m / (CTR+CTQ1+CT2) < 5.05, where d1m is the inner diameter of the second side of the first spacer element, CTR is the center thickness of the reflective polarizing element, CTQ1 is the center thickness of the first quarter-wave plate, and CT2 is the center thickness of the second lens.

[0010] In some embodiments of this application, the visual system further satisfies: 3.00≤f2 / D1m≤3.73, where f2 is the effective focal length of the second lens and D1m is the outer diameter of the second side of the first spacer element.

[0011] In some embodiments of this application, the visual system further satisfies: -2.70 < (R5 + R6) / D0m < -2.30, where R5 is the radius of curvature of the first side surface of the third lens, R6 is the radius of curvature of the second side surface of the third lens, and D0m is the outer diameter of the second side surface of the lens barrel.

[0012] In some embodiments of this application, the visual system further satisfies: 1.55 < f3 / (d0m+D0m) < 3.30, where f3 is the effective focal length of the third lens, d0m is the inner diameter of the second side of the lens barrel, and D0m is the outer diameter of the second side of the lens barrel.

[0013] In some embodiments of this application, the visual system further satisfies: 10.85 < (D0s - d0s) / (D0m - d0m) < 15.75, where D0s is the outer diameter of the first side of the lens barrel, d0s is the inner diameter of the first side of the lens barrel, D0m is the outer diameter of the second side of the lens barrel, and d0m is the inner diameter of the second side of the lens barrel.

[0014] In some embodiments of this application, the visual system further satisfies: 3.60 < (D1s + D1m) / f < 4.45, where D1s is the outer diameter of the first side of the first spacer element, D1m is the outer diameter of the second side of the first spacer element, and f is the effective focal length of the visual system.

[0015] In some embodiments of this application, the visual system further satisfies: 3.25 < f23 / L < 4.60, where f23 is the combined focal length of the second lens and the third lens, and L is the maximum height of the lens barrel.

[0016] In some embodiments of this application, the visual system further satisfies: 4.40 < d0min / EPD < 4.85, where d0min is the minimum inner diameter of the lens barrel and EPD is the entrance pupil diameter of the visual system.

[0017] In summary, under the condition that 5.90 < f23 / (CT2+CT3) < 8.90, the visual system will generate stray light near the first lens. Therefore, this application, by constraining the range of 4.40 < d0min / CT1 < 4.85 and 0.15 < T12 / (D1s-d1s) < 0.85, rationally designs the internal space of the lens barrel and the difference between the inner and outer diameters of the first spacer element, blocking stray light deflected towards the first lens without obstructing normal imaging light, thus directly suppressing stray light propagation at the optical path blocking level. When the upper limits of d0min / CT1 and T12 / (D1s-d1s) are exceeded, the gap between the first lens and the inner wall of the lens barrel widens. At this time, stray light refracted and deflected by the second and third lenses will enter this gap, undergoing multiple reflections on the inner wall of the lens barrel, forming diffuse stray light. This stray light propagates unrestricted towards the image surface, eventually forming numerous and scattered light spots. Meanwhile, the first spacer element cannot effectively block stray light that deviates towards the edge of the first lens. The stray light that should have been blocked by the spacer element passes directly through the gap and superimposes with the reflected light from the inner wall of the lens barrel, further increasing the number of light spots. When the lower limits of d0min / CT1 and T12 / (D1s-d1s) are exceeded, the edge of the first lens almost touches the inner wall of the lens barrel. At this time, stray light undergoes gap reflection between the edge of the first lens and the inner wall of the lens barrel (i.e., light reflects back and forth in a narrow space), and the energy gradually concentrates in a certain direction. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structural parameters of a visual system according to one embodiment of this application;

[0019] Figure 2 This is a schematic diagram of the visual system according to Embodiment 1 of this application;

[0020] Figure 3 This is a schematic diagram of the visual system according to Embodiment 2 of this application;

[0021] Figure 4 This is a schematic diagram of the visual system according to Embodiment 3 of this application;

[0022] Figure 5A A schematic diagram of the astigmatism curves of the visual system according to Embodiment 1, Embodiment 2 and Embodiment 3 of this application is shown.

[0023] Figure 5B A schematic diagram of the distortion curves of the visual system according to Embodiment 1, Embodiment 2 and Embodiment 3 of this application is shown;

[0024] Figure 6 This is a schematic diagram of the visual system according to Embodiment 4 of this application;

[0025] Figure 7 This is a schematic diagram of the visual system according to Embodiment 5 of this application;

[0026] Figure 8 This is a schematic diagram of the visual system according to Embodiment Six of this application;

[0027] Figure 9A A schematic diagram of the astigmatism curves of the visual system according to Embodiments 4, 5 and 6 of this application is shown.

[0028] Figure 9B A schematic diagram of the distortion curves of the visual system according to Embodiments 4, 5 and 6 of this application is shown.

[0029] Figure 10 This is a schematic diagram of the visual system according to Embodiment Seven of this application;

[0030] Figure 11 This is a schematic diagram of the visual system according to Embodiment 8 of this application;

[0031] Figure 12 This is a schematic diagram of the visual system according to Embodiment Nine of this application;

[0032] Figure 13AA schematic diagram of the astigmatism curves of the visual system according to Embodiments 7, 8 and 9 of this application is shown.

[0033] Figure 13B A schematic diagram of the distortion curves of the visual system according to Embodiments 7, 8 and 9 of this application is shown.

[0034] Figure 14 The stray light pattern of the visual system is shown when f23 / (CT2+CT3)=7.2, d0min / CT1=4.65 and T12 / (D1s-d1s)=0.55.

[0035] Figure 15 The stray light pattern of the visual system is shown when f23 / (CT2+CT3)=7.2, d0min / CT1=5.0 and T12 / (D1s-d1s)=1.05.

[0036] Figure 16 The stray light pattern of the visual system is shown when f23 / (CT2+CT3)=7.2, d0min / CT1=4.1 and T12 / (D1s-d1s)=0.1.

[0037] Explanation of reference numerals in the attached figures:

[0038] E1, first lens; E2, second lens; E3, third lens; P0, lens barrel; P1, first spacer element. Detailed Implementation

[0039] 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.

[0040] It should be noted that in this specification, the terms "first," "second," "third," 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 or the third lens.

[0041] 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.

[0042] 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. The surface shape in the paraxial region can be determined based on the sign of the R value (R refers to the radius of curvature of the paraxial region). Taking the first side as an example, when the R value is positive, it is determined to be convex, and when the R value is negative, it is determined to be concave; taking the second side as an example, when the R value is positive, it is determined to be concave, and when the R value is negative, it is determined to be convex.

[0043] 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.

[0044] 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.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other. The following embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this application. It should be pointed out that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] like Figure 1 and Figure 2As shown, this application provides a visual system, including a lens barrel P0 and a lens group assembled within the lens barrel P0; the lens group, from a first side to a second side, sequentially includes: a first lens E1 with positive optical power, the first side of the first lens E1 being convex; a second lens E2 with positive optical power, the first side of the second lens E2 being planar and the second side being convex; and a third lens E3 with positive optical power, the first side of the third lens E3 being concave and the second side being convex; a partial reflective element (BS) is disposed between the second lens E2 and the third lens E3; a first quarter-wave plate (QWP1) is attached to the first side of the second lens E2; a reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1); and a polarizer (LP) is attached to the image surface of the visual system. A second quarter-wave plate (QWP2) is attached to the first side of the first lens E1, and a first spacer element P1 is provided on the second side of the first lens E1; the visual system satisfies: 5.90 < f23 / (CT2+CT3) < 8.90; 4.40 < d0min / CT1 < 4.85 and 0.15 < T12 / (D1s-d1s) < 0.85; where f23 is the combined focal length of the second lens E2 and the third lens E3, CT2 is the center thickness of the second lens E2, CT3 is the center thickness of the third lens E3, d0min is the minimum inner diameter of the lens barrel P0, CT1 is the center thickness of the first lens E1, T12 is the axial distance from the second side of the first lens E1 to the first side of the second lens E2, D1s is the outer diameter of the first side of the first spacer element P1, and d1s is the inner diameter of the first side of the first spacer element P1.

[0047] like Figure 14 As shown, Figure 14 The image shows stray light spots when the visual system satisfies f23 / (CT2+CT3)=7.2, d0min / CT1=4.65, and T12 / (D1s-d1s)=0.55. The image shows a small number of spots, indicating that when the visual system meets the above conditions, there is little stray light interference in the image, and the visual system has good imaging quality.

[0048] like Figure 15 As shown, Figure 15The image shows stray light spots when the visual system satisfies f23 / (CT2+CT3)=7.2, d0min / CT1=5.0, and T12 / (D1s-d1s)=1.05. The image shows numerous stray spots scattered within a circular area. This is because the gap between the first lens E1 and the inner wall of the lens barrel P0 is too wide. At this time, stray light refracted and deflected by the second lens E2 and the third lens E3 enters this gap and undergoes multiple reflections on the inner wall of the lens barrel P0. Simultaneously, the first spacer element P1 cannot intercept the stray light deflected from the edge of the first lens E1. The two parts of stray light overlap, thus forming... Figure 15 The diffuse stray light in the image indicates that when the visual system exceeds the upper limit of the above conditional expression, the image is severely affected by stray light interference, and the imaging quality of the visual system deteriorates.

[0049] like Figure 16 As shown, Figure 16 The image shows stray light spots when the visual system satisfies f23 / (CT2+CT3)=7.2, d0min / CT1=4.1, and T12 / (D1s-d1s)=0.1. The image shows distinctly symmetrical bright spots. This is because the edge of the first lens E1 is almost in contact with the inner wall of the lens barrel P0. At this point, stray light undergoes gap reflection between the edge of the first lens E1 and the inner wall of the lens barrel P0, meaning the light is reflected back and forth within a narrow space, thus forming stray light spots. Figure 16 The light spot is concentrated in the medium energy range. This indicates that when the visual system exceeds the lower limit of the above conditional expression, the image is severely affected by stray light interference, and the imaging quality of the visual system deteriorates.

[0050] According to some embodiments of this application, the visual system further satisfies: 1.16 ≤ f1 / (d0s+D0s) ≤ 1.65, where f1 is the effective focal length of the first lens E1, d0s is the inner diameter of the first side of the lens barrel P0, and D0s is the outer diameter of the first side of the lens barrel P0. By reasonably controlling this conditional range, light utilization can be maximized, polarization control can be stabilized, and subsequent aberration correction effects can be guaranteed. Simultaneously, the feasibility of assembling the lens and lens barrel P0 can be ensured, guaranteeing sufficient strength of the lens barrel P0 and achieving a compact overall system design.

[0051] According to some embodiments of this application, the visual system also satisfies: 9.00 < d0m / CT3 < 12.80, where d0m is the inner diameter of the second side of the lens barrel P0, and CT3 is the center thickness of the third lens E3. By reasonably controlling this conditional range, it can be ensured that the emitted beam from the third lens E3 is unobstructed and free from stray light interference, stabilizing the aberration correction effect and polarization control accuracy, ultimately outputting an image with uniform illumination, clear sharpness, and high contrast; at the same time, it ensures reliable assembly of the third lens E3 (no eccentricity, no deformation), adapts to the installation dimensions of subsequent polarization elements, and achieves seamless integration of the system's backend.

[0052] According to some embodiments of this application, the visual system further satisfies: 2.45 < TD / EP01 < 3.45, where TD is the axial distance from the first side surface of the first lens E1 to the second side surface of the third lens E3, and EP01 is the distance along the optical axis from the first side surface of the lens barrel P0 to the first side surface of the first spacer element P1. By reasonably controlling this conditional range, "axial interference" between optical components and mechanical structures can be avoided, "axial positioning accuracy" of each component can be guaranteed, optical axis coaxiality can be improved, and the beam can be guaranteed to be "uninterrupted and undiverged" within the lens group. This stabilizes the working conditions of the front-end polarization element, avoids polarization distortion, and improves the imaging quality of the optical system. Simultaneously, the overall volume can be controlled to meet compactness requirements.

[0053] According to some embodiments of this application, the visual system further satisfies: 1.75 < L / (EP01+CP1) < 3.35, where L is the maximum height of the lens barrel P0, EP01 is the distance along the optical axis from the first side of the lens barrel P0 to the first side of the first spacer element P1, and CP1 is the maximum thickness of the first spacer element P1. By reasonably controlling this conditional range, front-end space redundancy can be avoided, the overall system volume can be made compact, and the rear-end space can be avoided from being encroached upon, which could lead to element compression or beam truncation, thus ensuring imaging quality.

[0054] According to some embodiments of this application, the visual system also satisfies: 3.25 < d1m / (CTR + CTQ1 + CT2) < 5.05, where d1m is the inner diameter of the second side of the first spacer element P1, CTR is the center thickness of the reflective polarizing element, CTQ1 is the center thickness of the first quarter-wave plate, and CT2 is the center thickness of the second lens E2. By reasonably controlling this condition range, stress-free attachment of the polarizing element can be ensured, polarization direction shift can be avoided, beam receiving efficiency of the second lens E2 can be guaranteed, optical power of the second lens E2 can be ensured, aberration correction of the cemented assembly can be effective, and imaging can be clear and uniform; at the same time, stray light introduced by the radial gap can be suppressed, ensuring the imaging quality of the optical system.

[0055] According to some embodiments of this application, the visual system also satisfies: 3.00 ≤ f2 / D1m ≤ 3.73, where f2 is the effective focal length of the second lens E2, and D1m is the outer diameter of the second side surface of the first spacer element P1. By reasonably controlling this conditional range, it is ensured that the beam output by the second lens E2 is lossless, the polarization conversion is accurate, and the cemented aberration correction is effective, resulting in a clear, uniform, and high-contrast image; at the same time, the mechanical strength of the first spacer element P1 is guaranteed, avoiding deformation or volume redundancy, thus balancing system stability and compactness.

[0056] According to some embodiments of this application, the visual system further satisfies: -2.70 < (R5 + R6) / D0m < -2.30, where R5 is the radius of curvature of the first side surface of the third lens E3, R6 is the radius of curvature of the second side surface of the third lens E3, and D0m is the outer diameter of the second side surface of the lens barrel P0. By reasonably controlling this conditional range, the cemented assembly is ensured to accurately correct spherical aberration, coma, and chromatic aberration, resulting in clear imaging and accurate color reproduction; the strength and external adaptability of the rear end of the lens barrel P0 are guaranteed, avoiding deformation or adaptation failure; and the outgoing beam is guaranteed to match the rear-end components, improving light utilization and polarization control accuracy.

[0057] According to some embodiments of this application, the visual system also satisfies: 1.55 < f3 / (d0m+D0m) < 3.30, where f3 is the effective focal length of the third lens E3, d0m is the inner diameter of the second side of the lens barrel P0, and D0m is the outer diameter of the second side of the lens barrel P0. By reasonably controlling this conditional range, it is ensured that the cemented assembly accurately corrects aberrations, the beam quality meets the standards, the back-end polarization element has good adaptability, and the image is clear and has high contrast; at the same time, it ensures the strength and capacity of the back end of the lens barrel P0, avoids deformation or volume redundancy, and balances stability and compactness.

[0058] According to some embodiments of this application, the visual system further satisfies: 10.85 < (D0s - d0s) / (D0m - d0m) < 15.75, where D0s is the outer diameter of the first side of the lens barrel P0, d0s is the inner diameter of the first side of the lens barrel P0, D0m is the outer diameter of the second side of the lens barrel P0, and d0m is the inner diameter of the second side of the lens barrel P0. By reasonably controlling this conditional range, high-strength support on the first side is ensured to prevent deformation, redundant wall thickness on the second side is avoided, system weight and cost are controlled, lightweight structure is achieved, and portability requirements are met.

[0059] According to some embodiments of this application, the visual system also satisfies: 3.60 < (D1s + D1m) / f < 4.45, where D1s is the outer diameter of the first side of the first spacer element P1, D1m is the outer diameter of the second side of the first spacer element P1, and f is the effective focal length of the visual system. By reasonably controlling the range of this condition, complete beam transmission is ensured, imaging loss is avoided, stray light interference is suppressed, and imaging purity is improved. Simultaneously, it can support the core components and ensure precise alignment of the optical axis.

[0060] According to some embodiments of this application, the visual system also satisfies: 3.25 < f23 / L < 4.60, where f23 is the combined focal length of the second lens E2 and the third lens E3, and L is the maximum height of the lens barrel P0. By reasonably controlling this conditional range, it is ensured that the cemented assembly accurately corrects aberrations, the beam is uninterrupted, and the image is clear and pure; the radial volume of the lens barrel P0 is controlled to adapt to lightweight and portable scenarios.

[0061] According to some embodiments of this application, the visual system also satisfies: 4.40 < d0min / EPD < 4.85, where d0min is the minimum inner diameter of the lens barrel P0, and EPD is the entrance pupil diameter of the visual system. By reasonably controlling this conditional range, complete beam transmission is ensured, and luminous flux, resolution, and uniformity meet the standards; the internal component dimensions are adapted to ensure stable assembly without shaking or jamming; at the same time, the volume and weight are controlled to suit portable scenarios and avoid redundancy.

[0062] It should be noted that those skilled in the art should understand that the number of spacers constituting the visual system can be changed to obtain the various results and advantages described in this specification without departing from the technical solutions claimed in this application, and this application does not specifically limit this. For example, the visual system may also include other numbers of spacers than those described in the above embodiments, as needed.

[0063] The following describes some specific, non-limiting embodiments of the above-described embodiments of this application in more detail with reference to the accompanying drawings. Figure 2 In the visual system provided in this application, the optical path undergoes two reflections. The image light emitted from the image plane (IMG) is first reflected once at the reflective polarizing element (RP), and then reflected a second time at the partial reflective element (BS) before exiting from the aperture (STO) to the human eye.

[0064] Example 1

[0065] like Figure 2 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0066] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0067] In this embodiment, the first lens E1, the second lens E2, and the third lens E3 all have positive optical power. The first side of the first lens E1 is convex and the second side of the first lens E1 is flat. The first side of the second lens E2 is flat and the second side of the second lens E2 is convex. The first side of the third lens E3 is concave and the second side of the third lens E3 is convex.

[0068] In addition, Table 1 shows the basic optical parameters of the visual system of Embodiment 1, where the units of radius of curvature and thickness / distance are millimeters (mm).

[0069] Table 1

[0070]

[0071] In this embodiment, the second side surface of the second lens E2 and the first side surface of the third lens E3 are both aspherical surfaces, and the surface shape x of each aspherical surface can be defined using, but is not limited to, the following aspherical formula:

[0072] ;

[0073] Where x is the distance vector from the vertex 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 reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the i-th order correction coefficient of the aspherical surface. Table 2 below gives the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, and A14 of each aspherical surface in Example 1.

[0074] Table 2

[0075]

[0076] Example 2

[0077] like Figure 3 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0078] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0079] It is worth noting that, compared with Embodiment 1 above, the visual system of Embodiment 2 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 2 is the same as Table 1, and the aspherical coefficient table is the same as Table 2. However, the visual system of Embodiment 2 has different structural parameters from the visual system of Embodiment 1 above. That is, the difference between Embodiment 2 and Embodiment 1 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and the spacer assembly in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 2 are shown in Table 8 below.

[0080] Example 3

[0081] like Figure 4 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0082] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0083] It is worth noting that, compared with Embodiment 1 above, the visual system of Embodiment 3 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 3 is the same as Table 1, and the aspherical coefficient table is the same as Table 2. However, the visual system of Embodiment 3 has different structural parameters than the visual system of Embodiment 1 above. That is, the difference between Embodiment 3 and Embodiment 1 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 3 are shown in Table 8 below.

[0084] The astigmatic curves of the visual system in Examples 1, 2, and 3 are as follows: Figure 5A As shown; the distortion curves of the visual system in Embodiments 1, 2, and 3 are as follows. Figure 5B As shown. According to Figure 5A and Figure 5B It can be seen that the visual systems in Embodiment 1, Embodiment 2 and Embodiment 3 can all achieve good imaging quality.

[0085] Example 4

[0086] like Figure 6 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0087] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0088] In this embodiment, the first lens E1, the second lens E2, and the third lens E3 all have positive optical power. The first side of the first lens E1 is convex and the second side of the first lens E1 is flat. The first side of the second lens E2 is flat and the second side of the second lens E2 is convex. The first side of the third lens E3 is concave and the second side of the third lens E3 is convex.

[0089] In addition, Table 3 shows the basic optical parameters of the visual system of Embodiment 4, where the units of radius of curvature and thickness / distance are millimeters (mm).

[0090] Table 3

[0091]

[0092] In this embodiment, the first side surface of the first lens E1, the second side surface of the second lens E2, and the first side surface of the third lens E3 are all aspherical surfaces. The surface shape x of each aspherical surface can be defined using, but is not limited to, the aspherical formula in Embodiment 1. Table 4 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, and A14 of each aspherical surface in Embodiment 4.

[0093] Table 4

[0094]

[0095] Example 5

[0096] like Figure 7As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0097] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0098] It is worth noting that, compared with Embodiment 4 above, the visual system of Embodiment 5 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 5 is the same as Table 3, and the aspherical coefficient table is the same as Table 4. However, the visual system of Embodiment 5 has different structural parameters than the visual system of Embodiment 4 above. That is, the difference between Embodiment 5 and Embodiment 4 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 5 are shown in Table 8 below.

[0099] Example 6

[0100] like Figure 8 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0101] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0102] It is worth noting that, compared with Embodiment 4 above, the visual system of Embodiment 6 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 6 is the same as Table 3, and the aspherical coefficient table is the same as Table 4. However, the visual system of Embodiment 6 has different structural parameters than the visual system of Embodiment 4 above. That is, the difference between Embodiment 6 and Embodiment 4 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 6 are shown in Table 8 below.

[0103] The astigmatic curves of the visual system in Examples 4, 5, and 6 are as follows: Figure 9A As shown; the distortion curves of the visual system in Examples 4, 5, and 6 are as follows. Figure 9B As shown. According to Figure 9A and Figure 9B It can be seen that the visual systems in Embodiments 4, 5 and 6 can all achieve good imaging quality.

[0104] Example 7

[0105] like Figure 10 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0106] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0107] In this embodiment, the first lens E1, the second lens E2, and the third lens E3 all have positive optical power. The first side surface of the first lens E1 is convex, and the second side surface of the first lens E1 is convex. The first side surface of the second lens E2 is flat, and the second side surface of the second lens E2 is convex. The first side surface of the third lens E3 is concave, and the second side surface of the third lens E3 is convex.

[0108] In addition, Table 5 shows the basic optical parameters of the visual system of Embodiment 7, where the units of radius of curvature and thickness / distance are millimeters (mm).

[0109] Table 5

[0110]

[0111] In this embodiment, the first side surface of the first lens E1, the second side surface of the second lens E2, and the first side surface of the third lens E3 are all aspherical surfaces. The surface shape x of each aspherical surface can be defined using, but is not limited to, the aspherical formula in Embodiment 1. Table 6 below shows the conic coefficient k and higher-order coefficients A4, A6, A8, A10, A12, and A14 of each aspherical surface in Embodiment 7.

[0112] Table 6

[0113]

[0114] Example 8

[0115] like Figure 11 As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0116] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0117] It is worth noting that, compared with Embodiment 7 above, the visual system of Embodiment 8 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 8 is the same as Table 5, and the aspherical coefficient table is the same as Table 6. However, the visual system of Embodiment 8 has different structural parameters than the visual system of Embodiment 7 above. That is, the difference between Embodiment 8 and Embodiment 7 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 8 are shown in Table 8 below.

[0118] Example 9

[0119] like Figure 12As shown, the visual system in this embodiment includes a lens barrel P0 and a lens group assembled within the lens barrel P0. The lens group includes, from the first side to the second side, a first lens E1, a second lens E2, and a third lens E3. A partial reflective element (BS) is disposed between the second lens E2 and the third lens E3. A first quarter-wave plate (QWP1) is attached to the first side of the second lens E2. A reflective polarizing element (RP) is attached to the first side of the first quarter-wave plate (QWP1). A polarizer (LP) is attached to the image plane (IMG). A second quarter-wave plate (QWP2) is attached to the first side of the polarizer (LP).

[0120] In this embodiment, a first spacer element P1 is also provided on the second side of the first lens E1.

[0121] It is worth noting that, compared with Embodiment 7 above, the visual system of Embodiment 9 has the same optical parameters, that is, the basic optical parameter table of the visual system of Embodiment 9 is the same as Table 5, and the aspherical coefficient table is the same as Table 6. However, the visual system of Embodiment 9 has different structural parameters than the visual system of Embodiment 7 above. That is, the difference between Embodiment 9 and Embodiment 7 is that the dimensional values ​​of some structural parameters of the lens barrel P0 and multiple spacer elements in the visual system are different. Specifically, the values ​​of each relevant structural parameter in Embodiment 9 are shown in Table 8 below.

[0122] The astigmatic curves of the visual system in Examples 7, 8, and 9 are as follows: Figure 13A As shown; the distortion curves of the visual system in Examples 7, 8, and 9 are as follows. Figure 13B As shown. According to Figure 13A and Figure 13B It can be seen that the visual systems in Embodiments 7, 8 and 9 can all achieve good imaging quality.

[0123] In summary, the other optical parameters of the visual systems in Examples 1 to 9 are shown in Table 7 below.

[0124] Table 7

[0125]

[0126] The structural parameters of the visual systems in Examples 1 to 9 are shown in Table 8 below. The unit of each structural parameter in the table is millimeters (mm).

[0127] Table 8

[0128]

[0129] The visual systems in Examples 1 to 9 satisfy the conditions in Table 9 below.

[0130] Table 9

[0131]

[0132] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0133] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A visual system, characterized in that, Includes a lens barrel and a lens assembly assembled within the lens barrel; The lens group, from the first side to the second side, sequentially includes: a first lens with positive optical power, the first side of which is convex; a second lens with positive optical power, the first side of which is planar and the second side of which is convex; and a third lens with positive optical power, the first side of which is concave and the second side of which is convex. A partial reflective element is disposed between the second lens and the third lens. A first quarter-wave plate is attached to the first side of the second lens, and a reflective polarizing element is attached to the first side of the first quarter-wave plate. A polarizer is attached to the image surface of the visual system, and a second quarter-wave plate is attached to the first side of the polarizer. A first spacer element is disposed on the second side of the first lens. The visual system satisfies: 5.90 < f23 / (CT2+CT3) < 8.90; 4.40 < d0min / CT1 < 4.85 and 0.15 < T12 / (D1s-d1s) < 0.85; where f23 is the combined focal length of the second lens and the third lens, CT2 is the center thickness of the second lens, CT3 is the center thickness of the third lens, d0min is the minimum inner diameter of the lens barrel, CT1 is the center thickness of the first lens, T12 is the axial distance from the second side of the first lens to the first side of the second lens, D1s is the outer diameter of the first side of the first spacer element, and d1s is the inner diameter of the first side of the first spacer element.

2. The visual system according to claim 1, characterized in that, The visual system also satisfies: 1.16≤f1 / (d0s+D0s)≤1.65, where f1 is the effective focal length of the first lens, d0s is the inner diameter of the first side of the lens barrel, and D0s is the outer diameter of the first side of the lens barrel.

3. The visual system according to claim 1, characterized in that, The visual system also satisfies: 9.00 < d0m / CT3 < 12.80, where d0m is the inner diameter of the second side of the lens barrel and CT3 is the center thickness of the third lens.

4. The visual system according to claim 1, characterized in that, The visual system also satisfies: 2.45 < TD / EP01 < 3.45, where TD is the axial distance from the first side of the first lens to the second side of the third lens, and EP01 is the distance along the optical axis from the first side of the lens barrel to the first side of the first spacer element.

5. The visual system according to claim 1, characterized in that, The visual system also satisfies: 1.75 < L / (EP01+CP1) < 3.35, where L is the maximum height of the lens barrel, EP01 is the distance from the first side of the lens barrel to the first side of the first spacer element along the optical axis, and CP1 is the maximum thickness of the first spacer element.

6. The visual system according to claim 1, characterized in that, The visual system also satisfies: 3.25 < d1m / (CTR+CTQ1+CT2) < 5.05, where d1m is the inner diameter of the second side of the first spacer element, CTR is the center thickness of the reflective polarizing element, CTQ1 is the center thickness of the first quarter-wave plate, and CT2 is the center thickness of the second lens.

7. The visual system according to claim 1, characterized in that, The visual system also satisfies: 3.00≤f2 / D1m≤3.73, where f2 is the effective focal length of the second lens and D1m is the outer diameter of the second side of the first spacer element.

8. The visual system according to claim 1, characterized in that, The visual system also satisfies: -2.70 < (R5 + R6) / D0m < -2.30, where R5 is the radius of curvature of the first side of the third lens, R6 is the radius of curvature of the second side of the third lens, and D0m is the outer diameter of the second side of the lens barrel.

9. The visual system according to claim 1, characterized in that, The visual system also satisfies: 1.55 < f3 / (d0m+D0m) < 3.30, where f3 is the effective focal length of the third lens, d0m is the inner diameter of the second side of the lens barrel, and D0m is the outer diameter of the second side of the lens barrel.

10. The visual system according to claim 1, characterized in that, The visual system also satisfies: 10.85 < (D0s - d0s) / (D0m - d0m) < 15.75, where D0s is the outer diameter of the first side of the lens barrel, d0s is the inner diameter of the first side of the lens barrel, D0m is the outer diameter of the second side of the lens barrel, and d0m is the inner diameter of the second side of the lens barrel.

11. The visual system according to claim 1, characterized in that, The visual system also satisfies: 3.60 < (D1s + D1m) / f < 4.45, where D1s is the outer diameter of the first side of the first spacer element, D1m is the outer diameter of the second side of the first spacer element, and f is the effective focal length of the visual system.

12. The visual system according to claim 1, characterized in that, The visual system also satisfies: 3.25 < f23 / L < 4.60, where f23 is the combined focal length of the second lens and the third lens, and L is the maximum height of the lens barrel.

13. The visual system according to claim 1, characterized in that, The visual system also satisfies: 4.40 < d0min / EPD < 4.85, where d0min is the minimum inner diameter of the lens barrel and EPD is the entrance pupil diameter of the visual system.

Images