Visual system

Abstract

The present invention provides a visual system, which comprises an optical element group and a lens barrel assembly; the optical element group comprises a first lens with positive focal power, a reflective polarizing element, a quarter wave plate, a second lens with positive focal power, a partial reflecting element and a third lens with positive focal power in sequence from the first side to the second side along the optical axis; the first side surface of the first lens is a convex surface, and the second side surface is a plane; the second side surface of the second lens is a convex surface; the second side surface of the third lens is a convex surface; the lens barrel assembly comprises a first lens barrel, a second lens barrel and a third lens barrel, the first lens is arranged in the first lens barrel, the second lens is arranged in the second lens barrel, and the third lens is arranged in the third lens barrel; the position of the first lens relative to the image surface of the second side on the optical axis is fixed, and the distance of the second lens relative to the first lens on the optical axis is adjustable; the visual system satisfies: 1.4<(das+dcs) / dbs<1.7, 4.7 <Lac / Δf<6.65。

Description

Technical Field

[0001] The present disclosure relates to the field of optical devices, and particularly to a visual system. Background Art

[0002] With the development of science and technology, virtual reality devices and / or augmented reality devices are widely used in fields such as gaming, education, medical treatment, and engineering. The visual systems of virtual reality devices and / or augmented reality devices usually adopt Fresnel lenses. The overall length of such visual systems using Fresnel lenses is relatively large, and the volume and weight are relatively large, which affects the user experience. Moreover, such visual systems using Fresnel lenses do not have the function of diopter adjustment and cannot meet the usage requirements of users with different diopters. Summary of the Invention

[0003] On the one hand, the present disclosure provides such a visual system, which includes an optical element group and a lens barrel assembly. The optical element group sequentially includes a first lens with positive optical power, a reflective polarizing element, a quarter-wave plate, a second lens with positive optical power, a partial reflection element, and a third lens with positive optical power along the optical axis from the first side to the second side. The first side of the first lens is convex, and the second side is flat. The second side of the second lens is convex. The second side of the third lens is convex. The lens barrel assembly includes a first lens barrel, a second lens barrel, and a third lens barrel. The first lens is placed in the first lens barrel, the second lens is placed in the second lens barrel, and the third lens is placed in the third lens barrel. Among them, the position of the first lens on the optical axis relative to the image plane on the second side is fixed, and the distance of the second lens on the optical axis relative to the first lens is adjustable. The number of lenses with optical power in the visual system is three. The visual system satisfies: 1.4 < (das + dcs) / dbs < 1.7, 4.7 < Lac / Δf < 6.65, where das is the inner diameter of the first side end face of the first lens barrel, dbs is the inner diameter of the first side end face of the second lens barrel, dcs is the inner diameter of the first side end face of the third lens barrel, Lac is the distance along the optical axis between the second side end face of the first lens barrel and the first side end face of the third lens barrel, and Δf is the difference between the total effective focal length of the visual system in the first state and the total effective focal length of the visual system in the second state.

[0004] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 1.25 < f1 / (Das + Dam) < 1.9, where f1 is the effective focal length of the first lens, Das is the outer diameter of the first side end face of the first lens barrel, and Dam is the outer diameter of the second side end face of the first lens barrel.

[0005] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 0.45 < Lb / (Dbm - dbm) < 2.35, where Lb is the distance along the optical axis between the first side end face and the second side end face of the second lens barrel, dbm is the inner diameter of the second side end face of the second lens barrel, and Dbm is the outer diameter of the second side end face of the second lens barrel.

[0006] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 8.86 ≤ dam / (CT1 + CTR + CTQ) ≤ 11.93, where CT1 is the central thickness of the first lens on the optical axis, CTR is the central thickness of the reflective polarizing element on the optical axis, CTQ is the central thickness of the quarter-wave plate on the optical axis, and dam is the inner diameter of the second side end face of the first lens barrel.

[0007] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 1.93 ≤ f2 / Dbs ≤ 2.20, where f2 is the effective focal length of the second lens and Dbs is the outer diameter of the first side end face of the second lens barrel.

[0008] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 0.14 ≤ |Dcm - dcs| / CT3 ≤ 4.35, where dcs is the inner diameter of the first side end face of the third lens barrel, Dcm is the outer diameter of the second side end face of the third lens barrel, and CT3 is the central thickness of the third lens on the optical axis.

[0009] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 4.8 mm < (fg / R1)×La < 5.65 mm, where fg is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, R1 is the radius of curvature of the first side face of the first lens, and La is the distance along the optical axis between the first side end face and the second side end face of the first lens barrel.

[0010] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: -1.65 < Dcs / R6 < -0.35, where R6 is the radius of curvature of the second side face of the third lens and Dcs is the outer diameter of the first side end face of the third lens barrel.

[0011] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 0.85 < Lc / CT3 < 2.7, where Lc is the distance along the optical axis between the first side end face and the second side end face of the third lens barrel and CT3 is the central thickness of the third lens on the optical axis.

[0012] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 4.09 ≤ (La + Lb + Lc) / ΔL ≤ 6.26, where La is the distance along the optical axis between the first end face and the second end face of the first lens barrel, Lb is the distance along the optical axis between the first end face and the second end face of the second lens barrel, Lc is the distance along the optical axis between the first end face and the second end face of the third lens barrel, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state.

[0013] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 0.36 ≤ TD / dcm ≤ 0.60, where TD is the on-axis distance from the first side face of the first lens to the second side face of the third lens, and dcm is the inner diameter of the second end face of the third lens barrel.

[0014] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 1.0 < EPD / Lac < 1.2, where EPD is the entrance pupil diameter of the visual system, and Lac is the distance along the optical axis between the second end face of the first lens barrel and the first end face of the third lens barrel.

[0015] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 0.05 < Δf / |Das - dcm| < 2.55, where Δf is the difference between the total effective focal length of the visual system in the first state and the total effective focal length of the visual system in the second state, Das is the outer diameter of the first end face of the first lens barrel, and dcm is the inner diameter of the second end face of the third lens barrel.

[0016] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 1.65 < |dbs - dbm| / ΔL < 2.95, where dbs is the inner diameter of the first end face of the second lens barrel, dbm is the inner diameter of the second end face of the second lens barrel, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state.

[0017] According to an exemplary embodiment of the present disclosure, the visual system further satisfies: 1.56 ≤ (Dam + Dcm) / Dbm ≤ 1.90, where Dam is the outer diameter of the second end face of the first lens barrel, Dbm is the outer diameter of the second end face of the second lens barrel, and Dcm is the outer diameter of the second end face of the third lens barrel.

[0018] The visual system provided by the present disclosure can realize the refraction of the light path by using a reflective polarizing element, a quarter wave plate and a partial reflective element, and can realize the diopter adjustment of the visual system by moving the second lens. At the same time, by constraining (das+dcs) / dbs and Lac / Δf respectively within a reasonable range, the visual system can be switched between the first state and the second state, the performance of the visual system can be improved, and the compact structural design of the visual system can be realized; the inner diameter of the first side end surface of the first lens barrel, the second lens barrel and the third lens barrel can also be restricted to reduce the light leakage phenomenon of the three lens barrels, and the light can be transmitted along a predetermined path inside the three lens barrels, reducing stray light and improving the imaging quality of the visual system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objects and advantages of the present disclosure will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings, in which:

[0020] Figure 1 A structural arrangement and parameter schematic diagram of a visual system according to an exemplary embodiment of the present disclosure are shown;

[0021] Figure 2 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 1 of the present disclosure;

[0022] Figure 3 A schematic diagram showing the structure of the visual system according to Embodiment 1 of the present disclosure when it is in the second state;

[0023] Figure 4 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 2 of the present disclosure;

[0024] Figure 5 A schematic diagram showing the structure of the visual system according to Embodiment 2 of the present disclosure when it is in the second state;

[0025] Figure 6 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 3 of the present disclosure;

[0026] Figure 7 A schematic diagram showing the structure of a visual system in a second state according to Embodiment 3 of the present disclosure;

[0027] Figure 8 shows the modulation transfer function curves when the visual system according to Embodiment 1, Embodiment 2 and Embodiment 3 of the present disclosure is in the first state;

[0028] Fig. 9 shows the modulation transfer function curves when the visual system according to Embodiment 1, Embodiment 2 and Embodiment 3 of the present disclosure is in the second state;

[0029] Fig.10 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 4 of the present disclosure;

[0030] Fig.11 A schematic diagram showing the structure of a visual system in a second state according to Embodiment 4 of the present disclosure;

[0031] Fig.12 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 5 of the present disclosure;

[0032] Fig.13 A schematic diagram showing the structure of the visual system according to Embodiment 5 of the present disclosure when it is in the second state;

[0033] Fig.14 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 6 of the present disclosure;

[0034] Fig.15 A schematic diagram showing the structure of the visual system according to Embodiment 6 of the present disclosure when it is in the second state;

[0035] Fig.16 shows a modulation transfer function curve when the visual system according to Embodiment 4, Embodiment 5 and Embodiment 6 of the present disclosure is in a first state;

[0036] Fig.17 shows the modulation transfer function curves when the visual system according to Embodiment 4, Embodiment 5 and Embodiment 6 of the present disclosure is in the second state;

[0037] Fig.18 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 7 of the present disclosure;

[0038] Fig.19 A schematic diagram showing the structure of a visual system in a second state according to Embodiment 7 of the present disclosure;

[0039] Fig. 20 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 8 of the present disclosure;

[0040] Fig.21 A schematic diagram showing the structure of a visual system in a second state according to Embodiment 8 of the present disclosure;

[0041] Fig. 22 A schematic diagram showing the structure of a visual system in a first state according to Embodiment 9 of the present disclosure;

[0042] Fig.23A schematic diagram showing the structure of a visual system in a second state according to Embodiment 9 of the present disclosure;

[0043] Fig.24 shows a modulation transfer function curve when the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present disclosure is in the first state;

[0044] Fig.25 shows a modulation transfer function curve when the visual system according to Embodiment 7, Embodiment 8 and Embodiment 9 of the present disclosure is in the second state;

[0045] Fig.26 The stray light simulation diagram is shown when the visual system satisfies (das+dcs) / dbs=1.3 and Lac / Δf=4.6;

[0046] Fig. 27 The stray light simulation diagram is shown when the visual system satisfies (das+dcs) / dbs=1.8 and Lac / Δf=6.8;

[0047] Fig.28 A stray light simulation diagram is shown when the visual system satisfies (das+dcs) / dbs=1.58 and Lac / Δf=6.33. DETAILED DESCRIPTION

[0048] In order to better understand the present disclosure, a more detailed description will be made of various aspects of the present disclosure with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present disclosure, and do not limit the scope of the present disclosure in any way. Throughout the specification, the same figure numerals refer to the same elements.

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

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

[0051] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the first side (e.g., the human eye side) is called the first side surface of the lens, and the surface of each lens closest to the second side (e.g., the display screen side) is called the second side surface of the lens.

[0052] It should also be understood that the terms "including" and / or "having", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. In addition, when describing embodiments of the present disclosure, the term "may" is used to mean "one or more embodiments of the present disclosure". And, the term "exemplary" is intended to refer to an example or illustration.

[0053] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this document.

[0054] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0055] The features, principles and other aspects of the present disclosure are described in detail below.

[0056] For visual systems, Fresnel lenses are usually used. Such visual systems using Fresnel lenses have a large total length, large volume and weight, which affects the user experience. In addition, the total effective focal length of such visual systems using Fresnel lenses is usually fixed, that is, the visual system does not have a zoom function, and thus cannot meet the requirements of users with different diopters. In order to achieve the diopter adjustment function, the visual system usually adopts a complex mechanical structure and multiple moving parts, which will further increase the volume of the visual system and make it impossible to achieve a compact design of the visual system.

[0057] The first aspect of the present disclosure provides a visual system, which may include an optical element group and a lens barrel assembly. The optical element group may include a first lens, a reflective polarizing element, a quarter-wave plate, a second lens, a partial reflection element, and a third lens arranged in sequence along the optical axis from the first side to the second side. Among them, the position of the first lens on the optical axis relative to the image plane is fixed, and the second lens can move relative to the first lens along the optical axis, that is, the distance of the second lens relative to the first lens on the optical axis is adjustable. The lens barrel assembly may include a first lens barrel, a second lens barrel, and a third lens barrel. Among them, the first lens is placed in the first lens barrel, the second lens is placed in the second lens barrel, and the third lens is placed in the third lens barrel. By using the reflective polarizing element, the quarter-wave plate, and the partial reflection element, the refraction and reflection of the optical path can be realized, and by moving the second lens, the visual system can be switched between the first state and the second state to realize the diopter adjustment of the visual system, so as to meet the usage requirements of users with different diopters, for example, to meet the usage requirements of users with diopters from +2D to -5D.

[0058] In one embodiment, the visual system may satisfy: 1.4 < (das + dcs) / dbs < 1.7, 4.7 < Lac / Δf < 6.65, where das is the inner diameter of the first side end face of the first lens barrel, dbs is the inner diameter of the first side end face of the second lens barrel, dcs is the inner diameter of the first side end face of the third lens barrel, Lac is the distance along the optical axis between the second side end face of the first lens barrel and the first side end face of the third lens barrel, and Δf is the difference between the total effective focal length of the visual system in the first state and the total effective focal length of the visual system in the second state. By restricting (das + dcs) / dbs and Lac / Δf within reasonable ranges respectively, the visual system can be switched between the first state and the second state to realize the diopter adjustment of the visual system. For example, the diopter of the visual system can be adjusted between +2D and -5D, and the performance of the visual system can be improved to realize the compact structural design of the visual system; at the same time, the inner diameters of the first side end faces of the first lens barrel, the second lens barrel, and the third lens barrel can be restricted, the light leakage phenomenon of these three lens barrels can be reduced, and the light can be transmitted along a predetermined path inside these three lens barrels, reducing stray light and improving the imaging quality of the visual system.

[0059] The following combines Fig.26 , Fig. 27 and Fig.28 to describe the imaging effect of the visual system. Among them, Fig.26 is the stray light simulation diagram when the visual system satisfies (das + dcs) / dbs = 1.3 and Lac / Δf = 4.6; Fig. 27 is the stray light simulation diagram when the visual system satisfies (das + dcs) / dbs = 1.8 and Lac / Δf = 6.8; Fig.28The stray light simulation diagram when the visual system satisfies (das + dcs) / dbs = 1.58 and Lac / Δf = 6.33. From Fig.26 it can be seen that when the visual system satisfies (das + dcs) / dbs = 1.3 and Lac / Δf = 4.6, the visual system has more stray light. From Fig. 27 it can be seen that when the visual system satisfies (das + dcs) / dbs = 1.8 and Lac / Δf = 6.8, the visual system has more stray light. However, when the optical system satisfies (das + dcs) / dbs = 1.58 and Lac / Δf = 6.33, the stray light of the visual system is significantly reduced (as Fig.28 ). It can be seen that by controlling the visual system to satisfy "1.4 < (das + dcs) / dbs < 1.7, 4.7 < Lac / Δf < 6.65", the stray light can be reduced and the imaging quality of the visual system can be improved.

[0060] In an exemplary embodiment, the first lens may have a positive optical power. The first side surface of the first lens may be convex, and the second side surface may be flat.

[0061] In an exemplary embodiment, the second lens may have a positive optical power. The first side surface of the second lens may be convex or concave, and the second side surface may be convex.

[0062] In an exemplary embodiment, the third lens may have a positive optical power. The first side surface of the third lens may be concave or flat, and the second side surface may be convex.

[0063] In an exemplary embodiment, the reflective polarizing element and the quarter-wave plate may be attached to each other and attached to the second side surface of the first lens. For example, the reflective polarizing element is at least partially attached to the second side surface of the first lens, and the quarter-wave plate is at least partially attached to the second side surface of the reflective polarizing element. The quarter-wave plate can be used to change the polarization state of light. For example, convert circularly polarized light to linearly polarized light, or convert linearly polarized light to circularly polarized light. The reflective polarizing element can reflect light in a predetermined direction (for example, linearly polarized light) and transmit light in a direction orthogonal to the predetermined direction (for example, linearly polarized light).

[0064] In an exemplary embodiment, the partial reflection element may be located on the second side surface of the second lens and at least partially attached to the second side surface of the second lens. The partial reflection element may have a semi-transmissive and semi-reflective effect on light. By providing a partial reflection element on the second side surface of the second lens and combining the reflective polarizing element and the quarter-wave plate, the light can be refracted and reflected multiple times, effectively reducing the body length of the visual system.

[0065] In an exemplary embodiment, the visual system may further include an aperture, which may be disposed between the first side and the first lens. Image light from the second side is transmitted to the aperture after multiple refractions and reflections through the third lens, the partially reflective element, the second lens, the quarter wave plate, the reflective polarizing element, the first lens, etc., and finally forms a virtual image at a predetermined position. As an example, the aperture may be, for example, the pupil of the user.

[0066] In an exemplary embodiment, an image surface may be provided on the second side of the visual system. A display screen may be provided on the image surface. The image light from the display screen may sequentially pass through the third lens, the second lens, and the quarter wave plate to reach the reflective polarizing element, and then be reflected at the reflective polarizing element to form a first reflected image light. The first reflected image light passes through the quarter wave plate, the second lens, and reaches the partially reflective element on the second side of the second lens, and then is reflected at the partially reflective element to form a second reflected image light. The second reflected image light sequentially passes through the second lens, the quarter wave plate, the reflective polarizing element, the first lens to the aperture (such as the user's pupil) and is finally imaged at a predetermined position. The visual system provided by the present disclosure folds the required optical path without affecting the projection quality by combining light reflection and refraction, thereby effectively shortening the main body length of the visual system.

[0067] In an exemplary embodiment, when the visual system is in the first state, the diopter of the visual system is +2D, which is suitable for users with a diopter of +2D; when the visual system is in the second state, the diopter of the visual system is -5D, which is suitable for users with a diopter of -5D. When the sign of the diopter is a negative sign, it indicates that the user is a myopic user; when the sign of the diopter is a positive sign, it indicates that the user is a hyperopic user; the specific value of the diopter indicates the diopter of the user. For example, a diopter of +1D indicates that the user's hyperopia is about 100 degrees, and a diopter of -1D indicates that the user's myopia is about 100 degrees.

[0068] It should be understood that the visual system having two states (for example, the first state and the second state) is merely exemplary, and the visual system may also have at least one other state besides the first state and the second state. When the visual system is in other states, the refractive power of the visual system is between +2D and -5D. The present disclosure does not specifically limit the number of states that the visual system has.

[0069] In an exemplary embodiment, the visual system has different virtual image distances in the first state and the second state, and the virtual image distance may be, for example, the on-axis distance from the virtual image formed by the image light from the second side at a predetermined position to the aperture stop.

[0070] In an exemplary embodiment, a lens barrel (e.g., a first lens barrel, a second lens barrel, a third lens barrel) may include a first side end face, a second side end face, an outer ring face, and an inner ring face. Among them, the end face closest to the first side of the lens barrel is the first side end face of the lens barrel, and the end face closest to the second side of the lens barrel is the second side end face of the lens barrel; in a direction perpendicular to the optical axis, the surface of the lens barrel farthest from the optical axis is the outer ring face, and the surface of the lens barrel closest to the optical axis is the inner ring face.

[0071] In an exemplary embodiment, the visual system may satisfy: 1.25 < f1 / (Das + Dam) < 1.9, where f1 is the effective focal length of the first lens, Das is the outer diameter of the first side end face of the first lens barrel, and Dam is the outer diameter of the second side end face of the first lens barrel. By controlling the above conditional expression, the ratio of the effective focal length of the first lens to the sum of the outer diameters of the first side end face and the second side end face of the first lens barrel can be constrained within a reasonable range, improving the light collection ability of the first lens, enabling as much light as possible to enter the visual system and be effectively utilized, improving the brightness and contrast of the image formed by the visual system, reducing aberration and distortion, and improving the overall performance of the visual system; at the same time, it can also make the structure of the visual system more compact, reduce the overall volume and weight of the visual system, and facilitate the carrying and installation of the visual system.

[0072] In an exemplary embodiment, the visual system may satisfy: 0.45 < Lb / (Dbm - dbm) < 2.35, where Lb is the distance along the optical axis between the first side end face and the second side end face of the second lens barrel, dbm is the inner diameter of the second side end face of the second lens barrel, and Dbm is the outer diameter of the second side end face of the second lens barrel. By controlling the above conditional expression, the ratio of the length of the second lens barrel in the direction of the optical axis to the wall thickness of the second lens barrel (e.g., the difference between the outer diameter and the inner diameter of the second lens barrel) can be constrained within a reasonable range, enhancing the structural strength of the second lens barrel to withstand the pressure and stress of internal optical elements and the external environment; at the same time, it can also make the second lens barrel have a longer length, enhancing the mechanical stability of the second lens barrel, and minimizing the deformation or displacement of the second lens barrel caused by vibration, shock, or temperature change as much as possible, improving the stability and accuracy of the visual system. In addition, a reasonable range of the length of the second lens barrel is conducive to achieving the accurate positioning of the second lens within the second lens barrel, reducing the degradation of the optical performance of the visual system caused by the offset or tilt of the second lens. The length of the second lens barrel in the direction of the optical axis and the difference between the outer diameter and the inner diameter of the second lens barrel will affect the thermal expansion performance of the visual system. By controlling Lb / (Dbm - dbm) within a reasonable range, the thermal expansion and contraction caused by temperature change can be reduced, improving the stability and accuracy of the visual system.

[0073] In an exemplary embodiment, the visual system may satisfy: 8.86≤dam / (CT1+CTR+CTQ)≤11.93, wherein CT1 is the center thickness of the first lens on the optical axis, CTR is the center thickness of the reflective polarizing element on the optical axis, CTQ is the center thickness of the quarter wave plate on the optical axis, and dam is the inner diameter of the second side end face of the first lens barrel. By controlling the above conditional expression, the space inside the first lens barrel can be effectively utilized, so that the first lens, the reflective polarizing element and the quarter wave plate can be accurately installed in the first lens barrel, and interference between the first lens, the reflective polarizing element and the quarter wave plate can be avoided; at the same time, the inner diameter of the second side end face of the second lens barrel can be limited, the positioning accuracy of the second lens and other optical elements in the second lens barrel can be improved, the accurate position of the second lens and other optical elements on the optical axis can be ensured, and the optical performance of the visual system can be improved. In addition, a reasonable range of the inner diameter of the second lens barrel can enable the second lens barrel to provide better mechanical support for the second lens and other optical elements, which is conducive to reducing the displacement of the optical elements caused by vibration or external force interference and improving the stability of the visual system.

[0074] In an exemplary embodiment, the visual system may satisfy: 1.93≤f2 / Dbs≤2.20, wherein f2 is the effective focal length of the second lens, and Dbs is the outer diameter of the first side end face of the second lens barrel. By controlling the above conditional expression, the ratio of the effective focal length of the second lens to the outer diameter of the first side end face of the second lens barrel can be constrained within a reasonable range, thereby improving the light collection ability of the second lens, so that as much light as possible can be effectively gathered by the second lens, thereby improving the brightness and contrast of the image formed by the visual system; at the same time, the mechanical stability of the second lens barrel can be improved, and the fluctuation of the optical performance of the visual system caused by vibration or external force interference can be reduced as much as possible, thereby improving the stability and accuracy of the visual system. In addition, in a visual system with high requirements for focusing ability, a reasonable f2 / Dbs range is conducive to improving the focusing accuracy of the visual system, improving image clarity, reducing aberrations, and thus improving the overall performance of the visual system.

[0075] In an exemplary embodiment, the visual system may satisfy: 0.14 ≤ |Dcm - dcs| / CT3 ≤ 4.35, where dcs is the inner diameter of the first side end face of the third lens barrel, Dcm is the outer diameter of the second side end face of the third lens barrel, and CT3 is the central thickness of the third lens on the optical axis. By controlling the above conditional expression, the ratio of the wall thickness of the third lens barrel to the central thickness of the third lens can be constrained, so that the third lens barrel has good structural strength, which is beneficial to achieving the accurate positioning of the third lens in the third lens barrel, and reducing the degradation of the optical performance of the visual system caused by the offset or tilt of the third lens; at the same time, the assembly process of the third lens barrel can be simplified, unnecessary material use can be reduced, while ensuring the assembly yield of the third lens barrel, reducing assembly errors, improving production efficiency and reducing costs.

[0076] In an exemplary embodiment, the visual system may satisfy: 4.8 mm < (fg / R1)×La < 5.65 mm, where fg is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, R1 is the radius of curvature of the first side face of the first lens, and La is the distance along the optical axis between the first side end face and the second side end face of the first lens barrel. By controlling the above conditional expression, it is beneficial to optimize the imaging quality of the visual system, reduce aberration, and improve the clarity and contrast of the image formed by the visual system; at the same time, further controlling the good matching of the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate with the radius of curvature of the first side face of the first lens is beneficial to improving the stability of the optical performance of the visual system during the entire diopter adjustment process.

[0077] In an exemplary embodiment, the visual system may satisfy: -1.65 < Dcs / R6 < -0.35, where R6 is the radius of curvature of the second side face of the third lens, and Dcs is the outer diameter of the first side end face of the third lens barrel. By controlling the above conditional expression, the ratio of the outer diameter of the first side end face of the third lens barrel to the radius of curvature of the second side face of the third lens can be constrained within a reasonable range, achieving a tight fit between the third lens and the third lens barrel, and avoiding the degradation of the optical performance of the visual system caused by looseness or excessive clearance between the third lens and the third lens barrel; at the same time, the mechanical stability of the third lens barrel can be improved, and the performance fluctuation of the visual system caused by vibration, impact or temperature change can be reduced as much as possible, and the stability of the visual system can be improved. In addition, a reasonable Dcs / R6 range can reduce the manufacturing difficulty of the third lens barrel and improve the manufacturing accuracy of the third lens barrel.

[0078] In an exemplary embodiment, the visual system may satisfy: 0.85 < Lc / CT3 < 2.7, where Lc is the distance along the optical axis between the first side end face and the second side end face of the third lens barrel, and CT3 is the central thickness of the third lens on the optical axis. By controlling the above conditional expression, the ratio of the length of the third lens barrel in the direction of the optical axis to the central thickness of the third lens can be constrained within a reasonable range, realizing a tight fit between the third lens and the third lens barrel, and avoiding the degradation of the optical performance of the visual system caused by looseness or excessive clearance between the third lens and the third lens barrel; at the same time, the internal space of the third lens barrel can be utilized more reasonably, so that the third lens and other optical elements can be accurately installed and will not interfere with each other. In addition, the third lens and the third lens barrel are prone to thermal expansion when the temperature changes. By controlling Lc / CT3 within a reasonable range, the displacement or deformation of the third lens caused by thermal expansion can be reduced, which is beneficial to maintaining stable optical performance of the visual system in an environment with large temperature changes or long-term use, enhancing the adaptability of the visual system to different environments such as temperature and humidity, improving the durability of the visual system, and extending the service life of the visual system.

[0079] In an exemplary embodiment, the visual system may satisfy: 4.09 ≤ (La + Lb + Lc) / ΔL ≤ 6.26, where La is the distance along the optical axis between the first side end face and the second side end face of the first lens barrel, Lb is the distance along the optical axis between the first side end face and the second side end face of the second lens barrel, Lc is the distance along the optical axis between the first side end face and the second side end face of the third lens barrel, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state. By controlling the above conditional expression, without affecting the diopter adjustment function of the visual system, the structure of the visual system can be made more compact, which is beneficial to the carrying and installation of the visual system; at the same time, problems such as image blurring, distortion, or chromatic aberration caused by the movement of the second lens during the diopter adjustment process can be reduced, so that the image formed by the visual system can remain clear and sharp at different diopters. In addition, by controlling (La + Lb + Lc) / ΔL within a reasonable range, the structural strength of each lens barrel can be optimized, and the optical performance fluctuations of the visual system caused by vibration or external force interference can be reduced, ensuring that the visual system can be used for a long time or in a harsh environment, and each lens barrel has good wear resistance, reducing surface damage caused by friction or scratching.

[0080] In an exemplary embodiment, the visual system may satisfy: 0.36 ≤ TD / dcm ≤ 0.60, where TD is the on-axis distance from the first side surface of the first lens to the second side surface of the third lens, and dcm is the inner diameter of the second side end surface of the third barrel. By controlling the above conditional expression, it is beneficial to reasonably distribute the spacing between the optical elements, avoid overcrowding or excessive gaps between the optical elements, thereby optimizing the overall structure of the visual system; at the same time, it can also reduce the light leakage phenomenon of the third barrel, reduce the stray light of the visual system, and improve the imaging quality of the visual system. In addition, the selection of TD and dcm will affect the cost of the visual system. By controlling TD / dcm within a reasonable range, while ensuring the optical performance of the visual system, more economical and easier-to-process materials can be selected, thereby reducing the overall cost of the visual system.

[0081] In an exemplary embodiment, the visual system may satisfy: 1.0 < EPD / Lac < 1.2, where EPD is the entrance pupil diameter of the visual system, and Lac is the distance along the optical axis between the second side end surface of the first barrel and the first side end surface of the third barrel. The entrance pupil diameter of the visual system affects the field of view of the visual system. By controlling the above conditional expression, the field of view of the visual system can be increased, enabling the user to observe a sufficiently wide scene, and at the same time, while satisfying the optical performance of the visual system, the distance along the optical axis between the second side end surface of the first barrel and the first side end surface of the third barrel can be further restricted, making the structure of the visual system more compact, and achieving miniaturization and portability of the visual system.

[0082] In an exemplary embodiment, the visual system may satisfy: 0.05 < Δf / |Das - dcm| < 2.55, where Δf is the difference between the total effective focal length of the visual system in the first state and the total effective focal length of the visual system in the second state, Das is the outer diameter of the first side end surface of the first barrel, and dcm is the inner diameter of the second side end surface of the third barrel. By controlling the above conditional expression, the dimensions between the barrels can be reasonably distributed, avoiding excessive gaps or too small gaps between the barrels and the corresponding lenses, improving the stability and reliability of the visual system, and the reasonable difference in barrel dimensions can effectively utilize the internal space of the barrels, ensuring that the optical elements can be accurately installed and will not interfere with each other; at the same time, it can also enable the visual system to have good imaging quality at different diopters, ensuring that users with different diopters can see clear images, so that the visual system can better adapt to different application scenarios and observation requirements, for example, adapting to scenarios such as different diopters or different observation distances. In addition, a reasonable range of Δf / |Das - dcm| can reduce the manufacturing difficulty of the barrels, improve the manufacturing accuracy of the barrels, and is more conducive to achieving precise manufacturing and assembly of the barrels.

[0083] In an exemplary embodiment, the visual system can satisfy: 1.65<|dbs-dbm| / ΔL<2.95, wherein dbs is the inner diameter of the first side end face of the second lens barrel, dbm is the inner diameter of the second side end face of the second lens barrel, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state. By controlling the above conditional formula, it is beneficial to optimize the performance of the visual system, so that the visual system can maintain a smooth and stable diopter adjustment effect when switching between the first state and the second state; at the same time, the difference in the inner diameters on both sides of the second lens barrel can be constrained, so that the size between the second lens barrel and the second lens is matched, and the gap between the second lens barrel and the second lens is prevented from being too large or too small, thereby improving the stability and reliability of the visual system. In addition, by controlling |dbs-dbm| / ΔL to be within a reasonable range, the visual system can have good imaging quality at different diopters, ensuring that users with different diopters can see clear images, so that the visual system can better adapt to different application scenarios and observation needs, for example, to different diopters or different observation distances.

[0084] In an exemplary embodiment, the visual system may satisfy: 1.56≤(Dam+Dcm) / Dbm≤1.90, wherein Dam is the outer diameter of the second side end face of the first lens barrel, Dbm is the outer diameter of the second side end face of the second lens barrel, and Dcm is the outer diameter of the second side end face of the third lens barrel. By controlling the above conditional formula, the size of each lens barrel can be reasonably allocated to avoid the gap between the lens barrel and the corresponding lens being too large or too small, thereby improving the stability and reliability of the visual system, and a reasonable lens barrel size ratio can effectively utilize the internal space of the lens barrel, ensuring that the optical elements can be accurately installed and will not interfere with each other. In addition, by controlling (Dam+Dcm) / Dbm to be within a reasonable range, it is beneficial to accurately locate the position of the optical element in the lens barrel, so that the visual system maintains the stability of optical performance.

[0085] The visual system according to the above-mentioned embodiment of the present disclosure may use multiple lenses, such as the three lenses described above. By reasonably allocating the parameters of the reflective polarizing element, the quarter-wave plate, each lens, and each lens barrel, the main body length of the visual system can be reduced, the imaging quality of the visual system can be improved, and the diopter adjustment of the visual system can be achieved, so that users with a diopter between +2D and -5D can see clear images. The visual system configured as above has the characteristics of diopter adjustment, lightness and thinness, and good imaging quality, and can well meet the use requirements of various portable electronic products in projection scenarios.

[0086] It should be understood that the present disclosure is concerned with the performance optimization of a three-piece visual system with a diopter adjustment function. Specifically, the present disclosure is concerned with, for example, how to achieve a compact structural design while achieving diopter adjustment, or, for example, how to improve the optical performance of a visual system while achieving diopter adjustment. The specific optical power distribution of the three lenses and the surface configuration of each lens are not the focus of the present disclosure, and these configurations can be adjusted accordingly as needed. In other words, although several specific optical power distributions and surface configurations are shown for the lenses in the embodiments of the present disclosure, it should be understood that these embodiments are merely exemplary, and the lenses in the present disclosure should not be limited to the several specific situations shown in the embodiments, but should be broadly understood as three lenses that achieve diopter adjustment.

[0087] In an embodiment of the present disclosure, at least one of the surfaces of the first lens, the second lens, and the third lens is an aspherical surface. The characteristic of an aspherical lens is that the curvature changes continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has a better curvature radius characteristic, and has the advantages of improving distortion aberration and improving astigmatism aberration. After adopting an aspherical lens, the aberration occurring during imaging can be eliminated as much as possible, thereby improving the imaging quality.

[0088] The second aspect of the present disclosure provides a visual system, which includes an optical element group and a lens barrel assembly. The optical element group sequentially includes a first lens with positive optical power, a reflective polarizing element, a quarter-wave plate, a second lens with positive optical power, a partial reflection element, and a third lens with positive optical power along the optical axis from the first side to the second side. The first side of the first lens is convex, and the second side is flat. The second side of the second lens is convex. The second side of the third lens is convex. The lens barrel assembly includes a first lens barrel, a second lens barrel, and a third lens barrel. The first lens is placed in the first lens barrel, the second lens is placed in the second lens barrel, and the third lens is placed in the third lens barrel. Among them, the position of the first lens on the optical axis relative to the image plane on the second side is fixed, and the distance of the second lens on the optical axis relative to the first lens is adjustable. The number of lenses with optical power in the visual system is three. The visual system satisfies: 4.09 ≤ (La + Lb + Lc) / ΔL ≤ 6.26, 4.7 < Lac / Δf < 6.65, where La is the distance along the optical axis between the first-side end face and the second-side end face of the first lens barrel, Lb is the distance along the optical axis between the first-side end face and the second-side end face of the second lens barrel, Lc is the distance along the optical axis between the first-side end face and the second-side end face of the third lens barrel, ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state, Lac is the distance along the optical axis between the second-side end face of the first lens barrel and the first-side end face of the third lens barrel, and Δf is the difference between the total effective focal length of the visual system in the first state and the total effective focal length of the visual system in the second state.

[0089] The visual system provided by the present disclosure can realize the folding and reflection of the optical path by using a reflective polarizing element, a quarter-wave plate, and a partial reflection element, and can realize the diopter adjustment of the visual system by moving the second lens. At the same time, by respectively constraining (La + Lb + Lc) / ΔL and Lac / Δf within reasonable ranges, the visual system can be switched between the first state and the second state. For example, the diopter of the visual system can be adjusted between +2D and -5D, and problems such as image blurring, distortion, or chromatic aberration caused by the movement of the second lens during the diopter adjustment process can be reduced, so that the image formed by the visual system can remain clear and sharp at different diopters; at the same time, without affecting the diopter adjustment function of the visual system, the structure of the visual system can be made more compact, which is beneficial to the carrying and installation of the visual system. In addition, by respectively constraining (La + Lb + Lc) / ΔL and Lac / Δf within reasonable ranges, the structural strength of each lens barrel can be optimized, the optical performance fluctuations caused by vibration or external force interference of the visual system can be reduced, ensuring that the visual system can be used for a long time or in a harsh environment, and each lens barrel has good wear resistance, reducing surface damage caused by friction or scratching.

[0090] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present disclosure, the number of lenses constituting the visual system can be changed to obtain the various results and advantages described in this specification.

[0091] Specific embodiments of the visual system applicable to the above-mentioned embodiments are further described below with reference to the accompanying drawings. Example 1

[0092] The following reference Figure 2 and Figure 3 Describe the visual system of Example 1 of the present disclosure.

[0093] like Figure 2 and Figure 3 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb and a third lens barrel Pc.

[0094] The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflective element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. A stop STO (not shown) may be located on the object side of the first lens E1. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side.

[0095] The first lens E1 has positive optical power, its first side surface S1 is convex, and the second side surface S2 is a plane. The second lens E2 has positive optical power, its first side surface S3 is convex, and the second side surface S4 is convex. The third lens E3 has positive optical power, its first side surface S5 is concave, and the second side surface S6 is convex. The reflective polarizing element RP and the quarter-wave plate QWP are attached to the second side surface S2 of the first lens E1. The partially reflecting element BS is attached to the second side surface S4 of the second lens E2. It should be noted that the surfaces S1, S2, S3, S4, S5 and S6 are Figure 2 and Figure 3 Not shown.

[0096] In this example, an image surface IMG may be provided on the second side of the visual system, and the image surface IMG may be provided with a display screen, for example. After the image light from the image surface IMG passes through the third lens E3, the second lens E2, the quarter-wave plate QWP in sequence and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2 and reaches the partially reflective element BS located on the second side of the second lens, a second reflection occurs at the partially reflective element BS. The light reflected for the second time passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture in sequence and is finally imaged at a predetermined position. For example, the light of the visual system after two reflections is finally projected to the user's pupil.

[0097] Table 1 shows the basic parameters of the visual system of Example 1, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface IMG passes through the components in the order of sequence number 15 to sequence number 1 and is finally projected to the user's pupil.

[0098] Table 1

[0099]

[0100] In this embodiment, the first side surface S1 of the first lens E1, the first side surface S3 and the second side surface S4 of the second lens E2, and the first side surface S5 and the second side surface S6 of the third lens E3 are aspherical surfaces, and the surface shape of each aspherical surface can be defined by but not limited to the following formula:

[0101] (1)

[0102] in, is the distance vector height from the vertex of the aspheric surface when the aspheric surface is at a height of h along the optical axis; c is the paraxial curvature of the aspheric surface, c=1 / R (i.e., the paraxial curvature c is the reciprocal of the curvature radius R in Table 1 above); k is the cone coefficient; Ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 gives the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the surfaces S1, S3, S4, S5 and S6 that can be used in Example 1.

[0103] Table 2

[0104]

[0105] In this embodiment, the visual system has a first state (eg, Figure 2 ) and the second state (e.g., Figure 3). The virtual image distance of the visual system is W1, the spacing distance between the quarter wave plate and the second lens is W2, and the spacing distance between the second lens and the third lens is W3. W1, W2, and W3 are variables that may change as the state of the visual system changes.

[0106] Table 3 shows the values ​​of W1, W2, W3 and the total effective focal length f of the visual optics of Example 1 under different states of the visual system.

[0107] Table 3

[0108] Example 2

[0109] The following reference Figure 4 and Figure 5 Describe the visual system of Example 2 of the present disclosure.

[0110] like Figure 4 and Figure 5 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1.

[0111] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 1, that is, the basic parameter table of the visual system of this embodiment is the same as Table 1, the aspheric coefficient table is the same as Table 2, and the table of W1, W2, W3 and f is the same as Table 3. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some elements in the lens barrel assembly are different. Example 3

[0112] The following reference Figure 6 and Figure 7 Describe the visual system of Example 3 of the present disclosure.

[0113] like Figure 6 and Figure 7 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1.

[0114] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 1, that is, the basic parameter table of the visual system of this embodiment is the same as Table 1, the aspheric coefficient table is the same as Table 2, and the table of W1, W2, W3 and f is the same as Table 3. The difference between this embodiment and Embodiment 1 is that the structural dimensions of at least some elements in the lens barrel assembly are different.

[0115] Figure 8 The modulation transfer function curves of Example 1, Example 2 and Example 3 when the visual system is in the first state are shown. Fig. 9 The modulation transfer function curves of the visual systems of Embodiment 1, Embodiment 2 and Embodiment 3 when they are in the second state are shown. Figure 8 and Fig. 9 From the above, it can be seen that the visual systems provided in Example 1, Example 2 and Example 3 can achieve good imaging quality in both the first state and the second state. Example 4

[0116] The following reference Fig.10 and Fig.11 Describe the visual system of Example 4 of the present disclosure.

[0117] like Fig.10 and Fig.11 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb and a third lens barrel Pc.

[0118] The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflective element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. A stop STO (not shown) may be located on the object side of the first lens E1. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side.

[0119] The first lens E1 has positive optical power, its first side surface S1 is convex, and the second side surface S2 is a plane. The second lens E2 has positive optical power, its first side surface S3 is concave, and the second side surface S4 is convex. The third lens E3 has positive optical power, its first side surface S5 is concave, and the second side surface S6 is convex. The reflective polarizing element RP and the quarter-wave plate QWP are attached to the second side surface S2 of the first lens E1. The partially reflecting element BS is attached to the second side surface S4 of the second lens E2. It should be noted that the surfaces S1, S2, S3, S4, S5 and S6 are Fig.10 and Fig.11 Not shown.

[0120] In this example, an image surface IMG may be provided on the second side of the visual system, and the image surface IMG may be provided with a display screen, for example. After the image light from the image surface IMG passes through the third lens E3, the second lens E2, the quarter-wave plate QWP in sequence and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2 and reaches the partially reflective element BS located on the second side of the second lens, a second reflection occurs at the partially reflective element BS. The light reflected for the second time passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture in sequence and is finally imaged at a predetermined position. For example, the light of the visual system after two reflections is finally projected to the user's pupil.

[0121] Table 4 shows the basic parameters of the visual system of Example 4, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface IMG passes through the components in the order of sequence number 15 to sequence number 1 and is finally projected to the user's pupil.

[0122] Table 4

[0123]

[0124] In this embodiment, the first side surface S1 of the first lens E1, the first side surface S3 and the second side surface S4 of the second lens E2, and the first side surface S5 and the second side surface S6 of the third lens E3 are aspherical surfaces. Table 5 shows the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the surfaces S1, S3, S4, S5 and S6 that can be used in Embodiment 4.

[0125] Table 5

[0126]

[0127] In this embodiment, the visual system has a first state (eg, Fig.10 ) and the second state (e.g., Fig.11 ). W1, W2 and W3 are variables that may change as the state of the visual system changes.

[0128] Table 6 shows the values ​​of W1, W2, W3 and the total effective focal length f of the visual optics of Example 4 under different states of the visual system.

[0129] Table 6

[0130] Example 5

[0131] The following reference Fig.12 and Fig.13 Describe the visual system of Example 5 of the present disclosure.

[0132] like Fig.12 and Fig.13 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1.

[0133] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 4, that is, the basic parameter table of the visual system of this embodiment is the same as Table 4, the aspheric coefficient table is the same as Table 5, and the table of W1, W2, W3 and f is the same as Table 6. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some elements in the lens barrel assembly are different. Example 6

[0134] The following reference Fig.14 and Fig.15 Describe the visual system of Example 6 of the present disclosure.

[0135] like Fig.14 and Fig.15 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1.

[0136] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 4, that is, the basic parameter table of the visual system of this embodiment is the same as Table 4, the aspheric coefficient table is the same as Table 5, and the table of W1, W2, W3 and f is the same as Table 6. The difference between this embodiment and Embodiment 4 is that the structural dimensions of at least some elements in the lens barrel assembly are different.

[0137] Fig.16 The modulation transfer function curves of Example 4, Example 5 and Example 6 when the visual system is in the first state are shown. Fig.17 The modulation transfer function curves of the visual systems of Embodiment 4, Embodiment 5 and Embodiment 6 when they are in the second state are shown. Fig.16 and Fig.17From the above, it can be seen that the visual systems provided in Example 4, Example 5 and Example 6 can achieve good imaging quality in both the first state and the second state. Example 7

[0138] The following reference Fig.18 and Fig.19 Describe the visual system of Example 7 of the present disclosure.

[0139] like Fig.18 and Fig.19 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb and a third lens barrel Pc.

[0140] The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflective element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. A stop STO (not shown) may be located on the object side of the first lens E1. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side.

[0141] The first lens E1 has positive optical power, and its first side surface S1 is convex, and the second side surface S2 is a plane. The second lens E2 has positive optical power, and its first side surface S3 is convex, and the second side surface S4 is convex. The third lens E3 has positive optical power, and its first side surface S5 is a plane, and the second side surface S6 is a convex surface. The reflective polarizing element RP and the quarter-wave plate QWP are attached to the second side surface S2 of the first lens E1. The partially reflecting element BS is attached to the second side surface S4 of the second lens E2. It should be noted that the surfaces S1, S2, S3, S4, S5 and S6 are Fig.18 and Fig.19 Not shown.

[0142] In this example, an image surface IMG may be provided on the second side of the visual system, and the image surface IMG may be provided with a display screen, for example. After the image light from the image surface IMG passes through the third lens E3, the second lens E2, the quarter-wave plate QWP in sequence and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. After the light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2 and reaches the partially reflective element BS located on the second side of the second lens, a second reflection occurs at the partially reflective element BS. The light reflected for the second time passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture in sequence and is finally imaged at a predetermined position. For example, the light of the visual system after two reflections is finally projected to the user's pupil. A protective glass E4 may also be provided between the image surface IMG and the third lens E3.

[0143] Table 7 shows the basic parameters of the visual system of Example 7, wherein the units of the radius of curvature and thickness / distance are all millimeters (mm). The image light from the image surface IMG passes through the components in the order of sequence number 17 to sequence number 1 and is finally projected to the user's pupil.

[0144] Table 7

[0145]

[0146] In this embodiment, the first side surface S1 of the first lens E1, the first side surface S3 and the second side surface S4 of the second lens E2, and the first side surface S5 and the second side surface S6 of the third lens E3 are aspherical surfaces. Table 8 shows the high-order coefficients A4, A6, A8, A10, A12, A14, A16, A18 and A20 of the surfaces S1, S3, S4, S5 and S6 that can be used in Embodiment 7.

[0147] Table 8

[0148]

[0149] In this embodiment, the visual system has a first state (eg, Fig.18 ) and the second state (e.g., Fig.19 ). W1, W2 and W3 are variables that may change as the state of the visual system changes.

[0150] Table 9 shows the values ​​of W1, W2, W3 and the total effective focal length f of the visual optics of Example 7 under different states of the visual system.

[0151] Table 9

[0152] Example 8

[0153] The following reference Fig. 20 and Fig.21 Describe the visual system of Example 8 of the present disclosure.

[0154] like Fig. 20 and Fig.21 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1. A protective glass E4 may also be provided between the image plane IMG and the third lens E3.

[0155] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 7, that is, the basic parameter table of the visual system of this embodiment is the same as Table 7, the aspheric coefficient table is the same as Table 8, and the table of W1, W2, W3 and f is the same as Table 9. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some elements in the lens barrel assembly are different. Example 9

[0156] The following reference Fig. 22 and Fig.23 Describe the visual system of Example 9 of the present disclosure.

[0157] like Fig. 22 and Fig.23 As shown, the visual system may include an optical element group and a lens barrel assembly. The lens barrel assembly may include a first lens barrel Pa, a second lens barrel Pb, and a third lens barrel Pc. The optical element group may include a first lens E1, a reflective polarizing element RP, a quarter wave plate QWP, a second lens E2, a partial reflection element BS (not shown), and a third lens E3 arranged in sequence from the first side to the second side along the optical axis. The aperture STO (not shown) may be located on the object side of the first lens E1. A protective glass E4 may also be provided between the image plane IMG and the third lens E3.

[0158] The structure of the optical element group of this embodiment is the same as that of the optical element group of Embodiment 7, that is, the basic parameter table of the visual system of this embodiment is the same as Table 7, the aspheric coefficient table is the same as Table 8, and the table of W1, W2, W3 and f is the same as Table 9. The difference between this embodiment and Embodiment 7 is that the structural dimensions of at least some elements in the lens barrel assembly are different.

[0159] Fig.24 The modulation transfer function curves of Example 7, Example 8 and Example 9 when the visual system is in the first state are shown. Fig.25 The modulation transfer function curves of the visual systems of Embodiment 7, Embodiment 8 and Embodiment 9 when they are in the second state are shown. Fig.24 and Fig.25 From the above, it can be seen that the visual systems provided in Example 7, Example 8 and Example 9 can achieve good imaging quality in both the first state and the second state.

[0160] Table 10 gives the basic parameters of each of Examples 1 to 9, such as the values ​​of f1, f2, f3, fg, TD, ΔL, Δf, and EPD.

[0161] Table 10

[0162]

[0163] Table 11 gives the values ​​of parameters such as das, dam, Das, Dam, dbs, dbm, Dbs, Dbm, dcs, dcm, Dcs, Dcm, Lac, La, Lb and Lc in each of Examples 1 to 9. The above parameters can be calculated according to Figure 1 The units of the parameters listed in Table 11 are all millimeters (mm).

[0164] Table 11

[0165]

[0166] Table 12 shows the values ​​of the conditional expressions of each of Examples 1 to 9.

[0167] Table 12

[0168]

[0169] The present disclosure also provides an optical device, which can be an independent projection device such as a projector, or a projection module integrated in a mobile electronic device such as a virtual reality device or an augmented reality device. The optical device is equipped with the visual system described above.

[0170] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other.

Claims

1. A visual system, characterized in that: include: The optical element group includes, in order from the first side to the second side along the optical axis: A first lens having positive optical power, wherein the first side surface is convex and the second side surface is flat; Reflective polarizing element; quarter wave plate; a second lens having positive optical power, wherein the second side surface of the second lens is convex; a partially reflective element; and a third lens element having positive power, wherein the second side surface of the third lens element is convex; The lens barrel assembly comprises a first lens barrel, a second lens barrel and a third lens barrel, wherein the first lens is placed in the first lens barrel, the second lens is placed in the second lens barrel, and the third lens is placed in the third lens barrel; Wherein, the position of the first lens on the optical axis relative to the image plane of the second side is fixed, and the distance of the second lens on the optical axis relative to the first lens is adjustable; The number of lenses having optical power in the visual system is three; The first side is a human eye side, and the second side is a display screen side; The visual system meets the following requirements: 1.4<(das+dcs) / dbs<1.7, 4.7 <Lac / Δf<6.65, Among them, das is the inner diameter of the first side end surface of the first lens barrel, dbs is the inner diameter of the first side end surface of the second lens barrel, dcs is the inner diameter of the first side end surface of the third lens barrel, Lac is the distance between the second side end surface of the first lens barrel and the first side end surface of the third lens barrel along the optical axis, and Δf is the difference between the total effective focal length when the visual system is in the first state and the total effective focal length when the visual system is in the second state.

2. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 1.25 <f1 / (Das+Dam)<1.9, Wherein, f1 is the effective focal length of the first lens, Das is the outer diameter of the first side end surface of the first lens barrel, and Dam is the outer diameter of the second side end surface of the first lens barrel.

3. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 0.45 <Lb / (Dbm-dbm)<2.35, Wherein, Lb is the distance between the first side end surface of the second lens barrel and the second side end surface of the second lens barrel along the optical axis, dbm is the inner diameter of the second side end surface of the second lens barrel, and Dbm is the outer diameter of the second side end surface of the second lens barrel.

4. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 8.86≤dam / (CT1+CTR+CTQ)≤11.93, Among them, CT1 is the center thickness of the first lens on the optical axis, CTR is the center thickness of the reflective polarizing element on the optical axis, CTQ is the center thickness of the quarter wave plate on the optical axis, and dam is the inner diameter of the second side end face of the first lens barrel.

5. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 1.93≤f2 / Dbs≤2.20, Wherein, f2 is the effective focal length of the second lens, and Dbs is the outer diameter of the first side end surface of the second lens barrel.

6. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 0.14≤ Dcm-dcs / CT3≤4.35, Wherein, dcs is the inner diameter of the first side end surface of the third lens barrel, Dcm is the outer diameter of the second side end surface of the third lens barrel, and CT3 is the center thickness of the third lens on the optical axis.

7. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 4.8mm<(fg / R1)×La<5.65mm, Among them, fg is the combined focal length of the first lens, the reflective polarizing element and the quarter-wave plate, R1 is the radius of curvature of the first side surface of the first lens, and La is the distance between the first side end surface of the first lens barrel and the second side end surface of the first lens barrel along the optical axis.

8. The visual system according to claim 1, wherein: The visual system also meets the following requirements: -1.65 <Dcs / R6<-0.35, Wherein, R6 is the curvature radius of the second side surface of the third lens, and Dcs is the outer diameter of the first side end surface of the third lens barrel.

9. The visual system according to claim 1, wherein: The visual system also meets the following requirements: 0.85 <Lc / CT3<2.7, Wherein, Lc is the distance between the first side end surface of the third lens barrel and the second side end surface of the third lens barrel along the optical axis, and CT3 is the center thickness of the third lens on the optical axis.

10. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 4.09≤(La+Lb+Lc) / ΔL≤6.26, Among them, La is the distance between the first side end surface of the first lens barrel and the second side end surface of the first lens barrel along the optical axis, Lb is the distance between the first side end surface of the second lens barrel and the second side end surface of the second lens barrel along the optical axis, Lc is the distance between the first side end surface of the third lens barrel and the second side end surface of the third lens barrel along the optical axis, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state.

11. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 0.36≤TD / dcm≤0.60, Wherein, TD is the on-axis distance from the first side surface of the first lens to the second side surface of the third lens, and dcm is the inner diameter of the second side end surface of the third lens barrel.

12. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 1.0 <EPD / Lac<1.2, Wherein, EPD is the entrance pupil diameter of the visual system, and Lac is the distance between the second side end surface of the first lens barrel and the first side end surface of the third lens barrel along the optical axis.

13. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 0.05<Δf / The-dcm <2.55, Among them, Δf is the difference between the total effective focal length when the visual system is in the first state and the total effective focal length when the visual system is in the second state, Das is the outer diameter of the first side end surface of the first lens barrel, and dcm is the inner diameter of the second side end surface of the third lens barrel.

14. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 1.65< dbs-dbm / ΔL<2.95, Among them, dbs is the inner diameter of the first side end surface of the second lens barrel, dbm is the inner diameter of the second side end surface of the second lens barrel, and ΔL is the movable distance of the second lens when the visual system switches between the first state and the second state.

15. The visual system according to any one of claims 1 to 9, wherein: The visual system also meets the following requirements: 1.56≤(Dam+Dcm) / Dbm≤1.90, Wherein, Dam is the outer diameter of the second side end surface of the first lens barrel, Dbm is the outer diameter of the second side end surface of the second lens barrel, and Dcm is the outer diameter of the second side end surface of the third lens barrel.

Images