Display system

Abstract

The utility model discloses a display system. The display system sequentially comprises a diaphragm, a first lens with positive focal power, a reflective polarization element, a quarter-wave plate, a second lens with positive focal power and a partial reflection element from a first side to a second side along an optical axis, the reflective polarizing element is used for reflecting the image light from the second side to form first-time reflected image light; the partial reflection element is used for reflecting the first reflection image light to form second reflection image light; the reflective polarizing element is attached to the quarter-wave plate and is attached to the second side surface of the first lens; the second lens is configured as a variable focal length lens; the display system has a plurality of states, virtual image distances of the display system in different states are different, and the virtual image distances are axial distances from a virtual image formed by image light from the second side at a preset position to the diaphragm; the display system meets the condition that VID is larger than or equal to-5000 mm and smaller than or equal to-250 mm, and the VID is the virtual image distance of the display system.

Description

Technical Field

[0001] This application relates to the field of optical devices, and more particularly to a display 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, healthcare, and engineering. The display system of virtual reality devices and / or augmented reality devices is a catadioptric optical system, which shortens the body length of the display system by refracting the optical path, reduces the volume and weight of virtual reality devices and / or augmented reality devices, and improves the comfort of users.

[0003] In order to make the display system suitable for users with different refractive powers, for example, myopic users and hyperopic users, the existing display system can adjust the virtual image distance of the display system by adjusting the distance between the display screen and the lens, so as to ensure that users with different refractive powers can see clear images. However, users cannot clearly perceive the virtual image distance, but only the clarity. And when adjusting the virtual image distance, users prefer to view objects at a short distance, which will cause the virtual image to be very close to the human eye, thus causing problems such as near vision eye fatigue. Summary of the Utility Model

[0004] On the one hand, this application provides a display system that sequentially includes a diaphragm, a first lens with positive optical power, a reflective polarizing element, a quarter-wave plate, a second lens with positive optical power, and a partial reflection element along the optical axis from the first side to the second side. The reflective polarizing element is used to reflect the image light from the second side to form a first reflected image light. The partial reflection element is used to reflect the first reflected image light to form a second reflected image light. The reflective polarizing element is attached to and adhered to the second side surface of the first lens together with the quarter-wave plate. The second lens is configured as a variable focal length lens. The display system has multiple states, and the virtual image distance of the display system is different in different states. The virtual image distance is the axial distance from the virtual image formed by the image light from the second side at a predetermined position to the diaphragm. The display system satisfies: -5000mm ≤ VID ≤ -250mm, where VID is the virtual image distance of the display system.

[0005] According to an exemplary embodiment of the present application, the reflective polarizing element is disposed on the second side surface of the first lens, the quarter-wave plate is disposed on the second side surface of the reflective polarizing element, and the partial reflection element is disposed on the second side surface of the second lens; the display system satisfies: 1.3 < N2 < 1.5, where N2 is the refractive index of the second lens.

[0006] According to an exemplary embodiment of the present application, the display system satisfies: 1.1 < f2e / f2d < 1.35, where f2e is the effective focal length of the second lens in the fifth state, and f2d is the effective focal length of the second lens in the fourth state.

[0007] According to an exemplary embodiment of the present application, the display system satisfies: 1.25 < |R3n / R4n| < 4.5, n = a, b, c, d, e, where when n = a, R3n is the radius of curvature of the first side of the second lens in the first state, and R4n is the radius of curvature of the second side of the second lens in the first state; when n = b, R3n is the radius of curvature of the first side of the second lens in the second state, and R4n is the radius of curvature of the second side of the second lens in the second state; when n = c, R3n is the radius of curvature of the first side of the second lens in the third state, and R4n is the radius of curvature of the second side of the second lens in the third state; when n = d, R3n is the radius of curvature of the first side of the second lens in the fourth state, and R4n is the radius of curvature of the second side of the second lens in the fourth state; when n = e, R3n is the radius of curvature of the first side of the second lens in the fifth state, and R4n is the radius of curvature of the second side of the second lens in the fifth state.

[0008] According to an exemplary embodiment of the present application, the display system satisfies: 0.2 < |FG1 / f2d| < 1.8, where FG1 is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, and f2d is the effective focal length of the second lens in the fourth state.

[0009] According to an exemplary embodiment of the present application, the display system satisfies: 2.7 < (CT2e - CT2d) / (fe - fd) < 8.85, where CT2e is the central thickness of the second lens on the optical axis in the fifth state, CT2d is the central thickness of the second lens on the optical axis in the fourth state, fe is the total effective focal length of the display system in the fifth state, and fd is the total effective focal length of the display system in the fourth state.

[0010] According to an exemplary embodiment of the present application, the display system satisfies: 22 mm < fn < 25.1 mm, n = a, b, c, d, e, where when n = a, fn is the total effective focal length of the display system in the first state; when n = b, fn is the total effective focal length of the display system in the second state; when n = c, fn is the total effective focal length of the display system in the third state; when n = d, fn is the total effective focal length of the display system in the fourth state; when n = e, fn is the total effective focal length of the display system in the fifth state.

[0011] According to an exemplary embodiment of the present application, the display system satisfies: 5.4 < FNOn < 6.3, where n = a, b, c, d, e. When n = a, FNOn is the f-number of the display system in the first state; when n = b, FNOn is the f-number of the display system in the second state; when n = c, FNOn is the f-number of the display system in the third state; when n = d, FNOn is the f-number of the display system in the fourth state; when n = e, FNOn is the f-number of the display system in the fifth state.

[0012] According to an exemplary embodiment of the present application, the display system satisfies: 3.8 < TTLa / fa × FNOa < 4.6, where TTLa is the on-axis distance from the first side surface of the first lens to the image plane of the display system in the first state, fa is the total effective focal length of the display system in the first state, and FNOa is the f-number of the display system in the first state.

[0013] According to an exemplary embodiment of the present application, the display system satisfies: 13 mm < EYEBOX < 17 mm, where EYEBOX is the on-axis distance from the stop to the first side surface of the first lens.

[0014] The display system provided by the present application can realize the folding and reflection of the optical path by using a reflective polarizing element, a quarter-wave plate, and a partially reflective element, effectively shortening the body length of the display system, reducing the volume and weight of the display system, and realizing the light weight of the display system. At the same time, by setting the second lens as a variable focal length lens, the display system can have multiple states, and the virtual image distance of the display system is different in different states. The virtual image distance of the display system can vary within the range of -5000 mm to -250 mm, and the display system has good MTF values in different states, ensuring that users with different diopters can see clear images. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings. Among them:

[0016] Figure 1 FIG. 1 shows a schematic structural diagram of the display system according to Embodiment 1 of the present application in the first state;

[0017] Figure 2 FIG. 2 shows a schematic structural diagram of the display system according to Embodiment 1 of the present application in the second state;

[0018] Figure 3 FIG. 3 shows a schematic structural diagram of the display system according to Embodiment 1 of the present application in the third state;

[0019] Figure 4Shows a schematic structural diagram of the display system according to Embodiment 1 of the present application in the fourth state;

[0020] Figure 5 Shows a schematic structural diagram of the display system according to Embodiment 1 of the present application in the fifth state;

[0021] Figure 6A 、 Figure 6B 、 Figure 6C 、 Figure 6D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function (MTF) curve of the display system according to Embodiment 1 of the present application in the first state;

[0022] Figure 7A 、 Figure 7B 、 Figure 7C 、 Figure 7D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 1 of the present application in the fourth state;

[0023] Figure 8A 、 Figure 8B 、 Figure 8C 、 Figure 8D Respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 1 of the present application in the fifth state;

[0024] Figure 9 Shows a schematic structural diagram of the display system according to Embodiment 2 of the present application in the first state;

[0025] Figure 10 Shows a schematic structural diagram of the display system according to Embodiment 2 of the present application in the second state;

[0026] Figure 11 Shows a schematic structural diagram of the display system according to Embodiment 2 of the present application in the third state;

[0027] Figure 12 Shows a schematic structural diagram of the display system according to Embodiment 2 of the present application in the fourth state;

[0028] Figure 13 Shows a schematic structural diagram of the display system according to Embodiment 2 of the present application in the fifth state;

[0029] Figure 14A 、 Figure 14B 、 Figure 14C 、 Figure 14Drespectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 2 of the present application in the first state;

[0030] Figure 15A , Figure 15B , Figure 15C , Figure 15D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 2 of the present application in the fourth state;

[0031] Figure 16A , Figure 16B , Figure 16C , Figure 16D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 2 of the present application in the fifth state;

[0032] Figure 17 shows the structural schematic diagram of the display system according to Embodiment 3 of the present application in the first state;

[0033] Figure 18 shows the structural schematic diagram of the display system according to Embodiment 3 of the present application in the second state;

[0034] Figure 19 shows the structural schematic diagram of the display system according to Embodiment 3 of the present application in the third state;

[0035] Figure 20 shows the structural schematic diagram of the display system according to Embodiment 3 of the present application in the fourth state;

[0036] Figure 21 shows the structural schematic diagram of the display system according to Embodiment 3 of the present application in the fifth state;

[0037] Figure 22A , Figure 22B , Figure 22C , Figure 22D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 3 of the present application in the first state;

[0038] Figure 23A , Figure 23B , Figure 23C , Figure 23D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 3 of the present application in the fourth state;

[0039] Figure 24A , Figure 24B , Figure 24C ,Figure 24D Respectively shown are the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 3 of the present application in the fifth state;

[0040] Figure 25 Shown is a schematic structural diagram of the display system according to Embodiment 4 of the present application in the first state;

[0041] Figure 26 Shown is a schematic structural diagram of the display system according to Embodiment 4 of the present application in the second state;

[0042] Figure 27 Shown is a schematic structural diagram of the display system according to Embodiment 4 of the present application in the third state;

[0043] Figure 28 Shown is a schematic structural diagram of the display system according to Embodiment 4 of the present application in the fourth state;

[0044] Figure 29 Shown is a schematic structural diagram of the display system according to Embodiment 4 of the present application in the fifth state;

[0045] Figure 30A 、 Figure 30B 、 Figure 30C 、 Figure 30D Respectively shown are the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 4 of the present application in the first state;

[0046] Figure 31A 、 Figure 31B 、 Figure 31C 、 Figure 31D Respectively shown are the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 4 of the present application in the fourth state;

[0047] Figure 32A 、 Figure 32B 、 Figure 32C 、 Figure 32D Respectively shown are the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 4 of the present application in the fifth state;

[0048] Figure 33 Shown is a schematic structural diagram of the display system according to Embodiment 5 of the present application in the first state;

[0049] Figure 34 Shown is a schematic structural diagram of the display system according to Embodiment 5 of the present application in the second state;

[0050] Figure 35Shows a schematic structural diagram of the display system according to Embodiment 5 of the present application in the third state;

[0051] Figure 36 Shows a schematic structural diagram of the display system according to Embodiment 5 of the present application in the fourth state;

[0052] Figure 37 Shows a schematic structural diagram of the display system according to Embodiment 5 of the present application in the fifth state;

[0053] Figure 38A and Figure 38B and Figure 38C and Figure 38D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 5 of the present application in the first state;

[0054] Figure 39A and Figure 39B and Figure 39C and Figure 39D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 5 of the present application in the fourth state; and

[0055] Figure 40A and Figure 40B and Figure 40C and Figure 40D respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve, and modulation transfer function curve of the display system according to Embodiment 5 of the present application in the fifth state. Detailed implementation manner

[0056] To better understand the present application, more detailed descriptions of various aspects of the present application will be made with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of the exemplary embodiments of the present application and do not limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements.

[0057] It should be noted that in this specification, the expressions such as first and second are only used to distinguish one feature from another feature and do not represent any limitation on the feature. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens.

[0058] In the drawings, for the sake of convenience of illustration, the thickness, size, and shape of the lens have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0059] In this text, 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 side of the human eye) is called the first side surface of the lens, and the surface of each lens closest to the second side (e.g., the side of the display screen) is called the second side surface of the lens.

[0060] It should also be understood that the terms "comprising", "including", "having", "containing" and / or "including", when used in this specification, mean 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 the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0062] It should be noted that, without conflict, the embodiments and features in the embodiments of the present application may be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0063] The features, principles and other aspects of the present application will be described in detail below.

[0064] Referring to Figures 1 to 5 、 Figures 9 to 13 、 Figures 17 to 21 、 Figures 25 to 29 and Figures 33 to 37 , a first aspect of the present application provides a display system that may include a diaphragm, a first lens, a reflective polarizing element, a quarter-wave plate, a second lens, and a partially reflective element arranged in sequence along the optical axis from the first side to the second side. By using the reflective polarizing element, the quarter-wave plate, and the partially reflective element, the refraction and reflection of the optical path can be realized, effectively shortening the body length of the display system, reducing the volume and weight of the display system, and realizing the lightweight of the display system.

[0065] In an exemplary embodiment, the reflective polarizing element is attached to the quarter-wave plate and adhered to the second side of the first lens. The quarter-wave plate can be used to change the polarization state of light. For example, it can convert circularly polarized light into linearly polarized light, or convert linearly polarized light into circularly polarized light. The reflective polarizing element can reflect light in a predetermined direction (e.g., linearly polarized light) and transmit light in a direction orthogonal to the predetermined direction (e.g., linearly polarized light).

[0066] In an exemplary embodiment, the partially reflective element can be disposed on the second side of the second lens. The partially reflective element has a semi-transmissive and semi-reflective effect on light. The combination of the partially reflective element, the reflective polarizing element, and the quarter-wave plate can cause light to be refracted and reflected multiple times, effectively reducing the body length of the display system.

[0067] In an exemplary embodiment, the image light from the second side passes through the partially reflective element, the second lens, the quarter-wave plate, the reflective polarizing element, the first lens, etc., and is refracted and reflected multiple times and then transmitted to the aperture, and finally forms a virtual image at a predetermined position. As an example, the aperture can be the user's pupil.

[0068] In an exemplary embodiment, the reflective polarizing element can be used to reflect the image light from the second side to form the first reflected image light. The partially reflective element can be used to reflect the first reflected image light to form the second reflected image light.

[0069] In an exemplary embodiment, an image surface can be provided on the second side of the display system. A display screen can be provided on the image surface. The image light from the display screen can sequentially pass through the second lens, the quarter-wave plate, reach the reflective polarizing element, and then be reflected at the reflective polarizing element to form the 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 the 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 (e.g., the user's pupil) and finally forms an image at a predetermined position. The display system provided by the present application folds the required optical path by a combination of light reflection and refraction without affecting the projection quality, effectively shortening the body length of the display system.

[0070] In an exemplary embodiment, the first side can be, for example, the human eye side, and the second side can be, for example, the display screen side. Correspondingly, the first side of each element (the first lens, the reflective polarizing element, the quarter-wave plate, the second lens, and the partially reflective element) can be referred to as the near-eye side, and the second side can be referred to as the near-screen side.

[0071] In an exemplary embodiment, the first lens can have a positive optical power.

[0072] In an exemplary embodiment, the second lens may have a positive optical power.

[0073] In an exemplary embodiment, the first side surface of the first lens may be convex or concave, and the second side surface may be convex or flat.

[0074] In an exemplary embodiment, the first side surface of the first lens may be convex or concave, and the second side surface may be convex.

[0075] In an exemplary embodiment, the second lens may be configured as a variable focal length lens. The display system may have multiple states, and the virtual image distances of the display system in different states are different. The virtual image distance may be the axial distance from the virtual image formed by the image light from the second side at a predetermined position to the aperture. By setting the second lens as a variable focal length lens, the display system can have multiple states, and the virtual image distances of the display system in different states are different. The display system has good MTF values in different states, ensuring that users with different refractive powers can see clear images. It should be understood that the concept of the virtual image distance in this article is the same, and the virtual image distance will not be elaborated hereinafter.

[0076] In an exemplary embodiment, the display system may satisfy: -5000 mm ≤ VID ≤ -250 mm, where VID is the virtual image distance of the display system. By controlling the virtual image distance of the display system to vary within the range of -5000 mm to -250 mm, users with different refractive powers can see clear images. For example, users with refractive powers from -0.2 D to -4 D can see clear images. Among them, refractive power = 1000 / VID. When the sign of the refractive power is negative, it indicates that the user is a myopic user. The specific value of the refractive power represents the refractive degree of the user. For example, a refractive power of -1 D means that the myopia degree of the user is about 100 degrees.

[0077] In an exemplary embodiment, the display system may have a first state, a second state, a third state, a fourth state, and a fifth state. Among all the states of the display system, the display system may have the largest virtual image distance in the fifth state, and the display system may have the smallest virtual image distance in the fourth state. The virtual image distance of the display system in the first state may be -1300 mm. The virtual image distance of the display system in the second state may be -500 mm. The virtual image distance of the display system in the third state may be -333.33 mm. The virtual image distance of the display system in the fourth state may be -250 mm. The virtual image distance of the display system in the fifth state may be -5000 mm. It should be understood that the number of states of the display system and the virtual image distances of the display system in different states are only exemplary, and the present application does not specifically limit the number of states of the display system and the virtual image distances of the display system in different states.

[0078] In an exemplary embodiment, the second lens may include a first deformation portion, a second deformation portion, and a glass substrate. The first deformation portion is disposed on a first side surface of the glass substrate and is used to adjust the shape of the first side surface of the second lens; the second deformation portion is disposed on a second side surface of the glass substrate and is used to adjust the shape of the second side surface of the second lens. By controlling the first deformation portion and / or the second deformation portion, the shape of the first side surface and / or the second side surface of the second lens can be adjusted, thereby adjusting the effective focal length of the second lens.

[0079] As an example, the first deformation portion may be, for example, a first film layer, the second deformation portion may be, for example, a second film layer, and a liquid may be filled in the first film layer and the second film layer. By squeezing the first film layer and / or the second film layer with a power device such as a motor, the shape of the first film layer and / or the second film layer can be changed, thereby changing the shape of the first side surface and / or the second side surface of the second lens, and realizing the adjustment of the effective focal length of the second lens.

[0080] In an exemplary embodiment, the display system may satisfy: 1.3 < N2 < 1.5, where N2 is the refractive index of the second lens. Reasonably configuring the refractive index of the second lens is beneficial to correcting the aberration of the display system.

[0081] In an exemplary embodiment, the display system may satisfy: 1.1 < f2e / f2d < 1.35, where f2e is the effective focal length of the second lens in the fifth state, and f2d is the effective focal length of the second lens in the fourth state. Reasonably configuring the ratio of the effective focal length of the second lens in the fifth state to the effective focal length of the second lens in the fourth state can enable the display system to have different virtual image distances in the fourth state and the fifth state, ensuring that users with different diopters can see clear images. At the same time, it can also prevent the effective focal length of the second lens from changing too much between the fourth state and the fifth state, and improve the service life of the display system. As an example, among all states of the display system, the display system may have the largest virtual image distance in the fifth state, and the display system may have the smallest virtual image distance in the fourth state.

[0082] In an exemplary embodiment, the display system may satisfy: 1.25 < |R3n / R4n| < 4.5, where n = a, b, c, d, e. When n = a, R3n is the radius of curvature of the first side surface of the second lens in the first state, and R4n is the radius of curvature of the second side surface of the second lens in the first state; when n = b, R3n is the radius of curvature of the first side surface of the second lens in the second state, and R4n is the radius of curvature of the second side surface of the second lens in the second state; when n = c, R3n is the radius of curvature of the first side surface of the second lens in the third state, and R4n is the radius of curvature of the second side surface of the second lens in the third state; when n = d, R3n is the radius of curvature of the first side surface of the second lens in the fourth state, and R4n is the radius of curvature of the second side surface of the second lens in the fourth state; when n = e, R3n is the radius of curvature of the first side surface of the second lens in the fifth state, and R4n is the radius of curvature of the second side surface of the second lens in the fifth state. By reasonably configuring the ratio of the radius of curvature of the first side surface and the second side surface of the second lens in different states, the second lens can have an appropriate effective focal length in different states, which is beneficial to realizing the adjustment of the total effective focal length of the display system. At the same time, it can also ensure that the second lens converges light and reduces the aberration of the display system.

[0083] In an exemplary embodiment, the display system may satisfy: 0.2 < |FG1 / f2d| < 1.8, where FG1 is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, and f2d is the effective focal length of the second lens in the fourth state. By reasonably configuring the ratio of the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate to the effective focal length of the second lens in the fourth state, the focal lengths of the components in the display system can be reasonably allocated, which is beneficial to ensuring that the display system has good optical performance.

[0084] In an exemplary embodiment, the display system may satisfy: 2.7 < (CT2e - CT2d) / (fe - fd) < 8.85, where CT2e is the central thickness of the second lens on the optical axis in the fifth state, CT2d is the central thickness of the second lens on the optical axis in the fourth state, fe is the total effective focal length of the display system in the fifth state, and fd is the total effective focal length of the display system in the fourth state. By controlling the above conditional formula, the central thickness of the second lens in the fourth state and the fifth state can be constrained within an appropriate range, improving the shape stability of the second lens, making the structure of the display system more compact, reducing the body length of the display system while ensuring the process feasibility of the second lens, realizing the miniaturization of the display system, and at the same time, the exit angle of the light exiting from the second lens can be restricted. As an example, among all states of the display system, the display system may have the largest virtual image distance in the fifth state and the smallest virtual image distance in the fourth state.

[0085] In an exemplary embodiment, the display system may satisfy: 22 mm < fn < 25.1 mm, where n = a, b, c, d, e. When n = a, fn is the total effective focal length of the display system in the first state; when n = b, fn is the total effective focal length of the display system in the second state; when n = c, fn is the total effective focal length of the display system in the third state; when n = d, fn is the total effective focal length of the display system in the fourth state; when n = e, fn is the total effective focal length of the display system in the fifth state. By controlling the total effective focal length of the display system to vary within the range of 22 mm to 25.1 mm, the virtual image distance of the display system can be made to vary within the range of -5000 mm to -250 mm, ensuring that users with different diopters can see clear images. For example, users with a diopter ranging from -0.2 D to -4 D can see clear images.

[0086] In an exemplary embodiment, the display system may satisfy: 5.4 < FNOn < 6.3, where n = a, b, c, d, e. When n = a, FNOn is the f-number of the display system in the first state; when n = b, FNOn is the f-number of the display system in the second state; when n = c, FNOn is the f-number of the display system in the third state; when n = d, FNOn is the f-number of the display system in the fourth state; when n = e, FNOn is the f-number of the display system in the fifth state. The entrance pupil diameter of the display system may be the size of the user's eye pupil. When the entrance pupil diameter of the display system is a fixed value, by controlling the f-number of the display system to vary within the range of 5.4 to 6.3, the change of the total effective focal length of the display system can be achieved, thereby ensuring that the display system has different virtual image distances in different states.

[0087] In an exemplary embodiment, the display system may satisfy: 3.8 < TTLa / fa×FNOa < 4.6, where TTLa is the on-axis distance from the first surface of the first lens to the image plane of the display system in the first state, fa is the total effective focal length of the display system in the first state, and FNOa is the f-number of the display system in the first state. By controlling the above conditional expression, the on-axis distance from the first surface of the first lens to the image plane of the display system in the first state can be constrained within a reasonable range, avoiding the problem of poor portability caused by an overly large body length of the display system, or avoiding the problems of excessive production difficulty and assembly difficulty caused by an overly thin first lens or second lens due to an overly small body length of the display system; at the same time, when the entrance pupil diameter of the display system is a fixed value, the f-number of the display system in the first state can be restricted, that is, the total effective focal length of the display system in the first state can be restricted, which is beneficial to the imaging of the display system. The entrance pupil diameter of the display system may be the size of the user's eye pupil.

[0088] In an exemplary embodiment, the display system may satisfy: 13 mm < EYEBOX < 17 mm, where EYEBOX is the axial distance from the aperture stop to the first side surface of the first lens. By reasonably configuring the axial distance from the aperture stop (e.g., the user's eye pupil) to the first side surface of the first lens, it is possible to avoid the problem that the user cannot clearly see the virtual image formed due to the user's eye pupil being too far from the first lens, and avoid the problem that the user's eyelashes or eyes touch the first lens due to the user's eye pupil being too close to the first lens; at the same time, it can also ensure that the display system can be adapted to users with different eye socket depths.

[0089] In an exemplary embodiment, the display system may satisfy: 10 mm < △f2 < 120 mm, where △f2 is the difference between the maximum focal length value and the minimum focal length value of the second lens. As an example, 16.4 mm < △f2 < 112.1 mm. By reasonably configuring the difference between the maximum focal length value and the minimum focal length value of the second lens, the virtual image distance of the display system can be varied within the range of -5000 mm to -250 mm, ensuring that users with different diopters can see clear images. For example, users with a diopter of -0.2 D to -4 D can see clear images.

[0090] The display system according to the above embodiments of the present application may employ multiple lenses, such as the two lenses described above. By reasonably allocating the parameters of the reflective polarizing element, the quarter-wave plate, and each lens, the body length of the display system can be reduced, the comfort of the user can be improved, and at the same time, the virtual image distance of the display system can be varied within the range of -5000 mm to -250 mm, ensuring that users with a diopter of -0.2 D to -4 D can all see clear images. The display system configured as above has the characteristics of miniaturization and good imaging quality, and can well meet the usage requirements of various portable electronic products in the projection scenario.

[0091] In an embodiment of the present application, the first side surface of the first lens is an aspherical surface. The characteristics of an aspherical lens are that the curvature continuously changes from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics and has the advantages of improving distortion aberration and improving astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0092] Refer to Figures 1 to 5 、 Figures 9 to 13 、 Figures 17 to 21 、 Figures 25 to 29 and Figures 33 to 37, a second aspect of the present application provides a display system which may sequentially include a diaphragm, a first lens with positive optical power, a reflective polarizing element, a quarter-wave plate, a second lens with positive optical power, and a partial reflection element along the optical axis from the first side to the second side. The reflective polarizing element is used to reflect the image light from the second side to form a first reflected image light. The partial reflection element is used to reflect the first reflected image light to form a second reflected image light. The reflective polarizing element is attached to and adheres to the second side surface of the first lens in combination with the quarter-wave plate. The second lens may be configured as a variable-focus lens. The display system may have multiple states, and the virtual image distances of the display system in different states are different. The virtual image distance may be the axial distance from the virtual image formed by the image light from the second side at a predetermined position to the diaphragm.

[0093] The display system may satisfy: 10mm < △f2 < 120mm, where △f2 is the difference between the maximum focal length value and the minimum focal length value of the second lens. The display system provided by the present application can realize the folding and reflection of the optical path by using the reflective polarizing element, the quarter-wave plate, and the partial reflection element, effectively shortening the body length of the display system, reducing the volume and weight of the display system, and realizing the light-weight of the display system. At the same time, by setting the second lens as a variable-focus lens and reasonably configuring the difference between the maximum focal length value and the minimum focal length value of the second lens, the virtual image distances of the display system in different states can be different, and the display system has good MTF values in different states, ensuring that users with different diopters can see clear images. For example, users with diopters from -0.2D to -4D can see clear images.

[0094] However, those skilled in the art should understand that without departing from the technical solutions claimed in the present application, the number of lenses constituting the display system can be changed to obtain the various results and advantages described in this specification.

[0095] The following further describes specific embodiments of the display system applicable to the above embodiments with reference to the accompanying drawings.

[0096] Example 1

[0097] The following refers to Figures 1 to 5 , Figures 6A to 6D , Figures 7A to 7D , Figures 8A to 8D to describe the display system of Embodiment 1.

[0098] As Figures 1 to 5As shown, the display system may include a stop STO, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, and a partial reflection element BS arranged in sequence along the optical axis from the first side to the second side. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surfaces of each element are all referred to as the near-eye side surfaces, and the second side surfaces are all referred to as the near-screen side surfaces.

[0099] The first lens E1 has a positive optical power. Its near-eye side surface S1 is concave, and its near-screen side surface S2 is convex. The reflective polarizing element RP has a near-eye side surface and a near-screen side surface S3. The near-eye side surface of the reflective polarizing element RP is attached to the near-screen side surface S2 of the first lens E1. The quarter-wave plate QWP has a near-eye side surface and a near-screen side surface S4. The near-eye side surface of the quarter-wave plate QWP is attached to the near-screen side surface S3 of the reflective polarizing element RP. The second lens E2 has a positive optical power. Its near-eye side surface S5 is concave, and its near-screen side surface S6 is convex. The partial reflection element BS is attached to the near-screen side surface S6 of the second lens E2.

[0100] In this example, an image plane IMG may be provided on the second side of the display system, and a display screen may be provided on the image plane IMG. After the image light from the image plane IMG sequentially passes through the second lens E2, the quarter-wave plate QWP, and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. The light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2, and reaches the partial reflection element BS located on the near-screen side surface of the second lens E2, where a second reflection occurs. The light reflected for the second time sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the stop (such as the user's eye pupil) and finally forms an image at a predetermined position. For example, the light rays after two reflections of this display system are finally projected into the user's eye pupil. A protective glass E3 may also be provided between the image plane IMG and the second lens E2.

[0101] Table 1 shows the basic parameter table of the display system of Embodiment 1, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0102]

[0103]

[0104] Table 1

[0105] In this embodiment, the display system has a first state (abbreviated as a), a second state (abbreviated as b), a third state (abbreviated as c), a fourth state (abbreviated as d), and a fifth state (abbreviated as e). Among them, the virtual image distance of the display system is D1, the central thickness of the second lens on the optical axis is D2, the radius of curvature of the first side surface of the second lens is W1, the radius of curvature of the second side surface of the second lens is W2, and D1, D2, W1, and W2 are variables that can change with the change of the display system state.

[0106] Table 2 shows the values of D1, D2, W1, W2, f2, and f in Embodiment 1 under different states of the display system.

[0107] Status a b c d e D1 (mm) -1300 -500 -333.33 -250 -5000 D2 (mm) 6.50 6.0928 5.7157 5.3392 6.7585 W1 (mm) -167.01 -188.43 -206.49 -226.61 -160.59 W2 (mm) -51.01 -51.19 -51.07 -50.91 -51.24 f2 (mm) 222.47 213.98 206.98 200.60 228.16 f (mm) 24.76 24.76 24.63 24.47 24.91

[0108] Table 2

[0109] In this embodiment, the near-eye side surface S1 of the first lens E1 is an aspherical surface, and the surface profile x of the aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0110]

[0111] Among them, x is the distance sagitta from the vertex of the aspherical surface when the aspherical surface is at a position with a height of h along the optical axis direction; c is the paraxial curvature of the aspherical surface, c = 1 / R (that is, 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 correction coefficient of the i-th order of the aspherical surface. Table 3 gives the high-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 , and A 20 that can be used for the aspherical surface S1 in Embodiment 1.

[0112] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2E-06 7E-09 -3E-11 6E-14 -6E-17 0E+00 0E+00 0E+00 0E+00

[0113] Table 3

[0114] Figure 6A shows the axial chromatic aberration curve of the display system in Embodiment 1 in the first state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 6B shows the astigmatism curve of the display system in Embodiment 1 in the first state, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 6C shows the distortion curve of the display system in Embodiment 1 in the first state, which represents the distortion magnitude values corresponding to different field angles. Figure 6D shows the modulation transfer function curve of the display system in Embodiment 1 in the first state. According toFigures 6A to 6D It can be seen that the display system given in Embodiment 1 can achieve good imaging quality in the first state.

[0115] Figure 7A The axial chromatic aberration curve of the display system of Embodiment 1 in the fourth state is shown, which represents the deviation of the convergence point of the light ray with a wavelength of 555 nm after passing through the display system. Figure 7B The astigmatism curve of the display system of Embodiment 1 in the fourth state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles of view. Figure 7C The distortion curve of the display system of Embodiment 1 in the fourth state is shown, which represents the distortion magnitude values corresponding to different field angles of view. Figure 7D The modulation transfer function curve of the display system of Embodiment 1 in the fourth state is shown. According to Figures 7A to 7D It can be seen that the display system given in Embodiment 1 can achieve good imaging quality in the fourth state.

[0116] Figure 8A The axial chromatic aberration curve of the display system of Embodiment 1 in the fifth state is shown, which represents the deviation of the convergence point of the light ray with a wavelength of 555 nm after passing through the display system. Figure 8B The astigmatism curve of the display system of Embodiment 1 in the fifth state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles of view. Figure 8C The distortion curve of the display system of Embodiment 1 in the fifth state is shown, which represents the distortion magnitude values corresponding to different field angles of view. Figure 8D The modulation transfer function curve of the display system of Embodiment 1 in the fifth state is shown. According to Figures 8A to 8D It can be seen that the display system given in Embodiment 1 can achieve good imaging quality in the fifth state.

[0117] Example 2

[0118] The following refers to Figures 9 to 13 、 Figures 14A to 14D 、 Figures 15A to 15D 、 Figures 16A to 16D to describe the display system of Embodiment 2.

[0119] As Figures 9 to 13 shown, the display system may include a stop STO, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, and a partially reflective element BS arranged in sequence along the optical axis from the first side to the second side. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surface of each element is called the near-human-eye side surface, and the second side surface is called the near-screen side surface.

[0120] The first lens E1 has a positive focal power. Its side S1 near the human eye is convex, and its side S2 near the screen is convex. The reflective polarizing element RP has a side near the human eye and a side S3 near the screen. The side of the reflective polarizing element RP near the human eye is attached to the side S2 of the first lens E1 near the screen. The quarter-wave plate QWP has a side near the human eye and a side S4 near the screen. The side of the quarter-wave plate QWP near the human eye is attached to the side S3 of the reflective polarizing element RP near the screen. The second lens E2 has a positive focal power. Its side S5 near the human eye is concave, and its side S6 near the screen is convex. The partial reflection element BS is attached to the side S6 of the second lens E2 near the screen.

[0121] In this example, an image plane IMG can be provided on the second side of the display system, and a display screen can be provided on the image plane IMG. After the image light from the image plane IMG sequentially passes through the second lens E2, the quarter-wave plate QWP, and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. The light after the first reflection passes through the quarter-wave plate QWP, the second lens E2, and reaches the partial reflection element BS located on the side of the second lens E2 near the screen, and a second reflection occurs at the partial reflection element BS. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture (such as the user's eye pupil) and finally forms an image at a predetermined position. For example, the light after two reflections of the display system is finally projected into the user's eye pupil. A protective glass E3 can also be provided between the image plane IMG and the second lens E2.

[0122] Table 4 shows the basic parameter table of the display system of Embodiment 2, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0123]

[0124]

[0125] Table 4

[0126] In this embodiment, the display system has a first state (abbreviated as a), a second state (abbreviated as b), a third state (abbreviated as c), a fourth state (abbreviated as d), and a fifth state (abbreviated as e). Among them, the virtual image distance of the display system is D1, the central thickness of the second lens on the optical axis is D2, the radius of curvature of the first side of the second lens is W1, the radius of curvature of the second side of the second lens is W2, and D1, D2, W1, and W2 are variables, which can change with the change of the state of the display system.

[0127] Table 5 shows the values of D1, D2, W1, W2, f2, and f of Embodiment 2 in different states of the display system.

[0128] Status a b c d e D1 (mm) -1300 -500 -333.33 -250 -5000 D2 (mm) 3.7509 3.4123 3.1364 2.8570 3.8734 W1 (mm) -56.56 -59.13 -61.26 -63.37 -55.33 W2 (mm) -41.12 -41.08 -41.02 -40.91 -41.00 f2 (mm) 436.70 395.94 367.34 343.82 455.88 f (mm) 22.28 22.23 22.17 22.09 22.21

[0129] Table 5

[0130] In this embodiment, the side S1 of the first lens E1 close to the human eye is an aspherical surface. Table 6 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 , and A 20 for the aspherical surface S1 that can be used in Example 2.

[0131] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -1.4E-06 6.0E-09 -2.5E-11 5.5E-14 -5.1E-17 0.0E+00 0.0E+00 0.0E+00 0.0E+00

[0132] Table 6

[0133] Figure 14A shows the axial chromatic aberration curve of the display system in Example 2 in the first state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 14B shows the astigmatism curve of the display system in Example 2 in the first state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles. Figure 14C shows the distortion curve of the display system in Example 2 in the first state, which represents the distortion magnitude values corresponding to different field angles. Figure 14D shows the modulation transfer function curve of the display system in Example 2 in the first state. According to Figures 14A to 14D , it can be seen that the display system given in Example 2 can achieve good imaging quality in the first state.

[0134] Figure 15A shows the axial chromatic aberration curve of the display system in Example 2 in the fourth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 15B shows the astigmatism curve of the display system in Example 2 in the fourth state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles. Figure 15C shows the distortion curve of the display system in Example 2 in the fourth state, which represents the distortion magnitude values corresponding to different field angles. Figure 15D shows the modulation transfer function curve of the display system in Example 2 in the fourth state. According to Figures 15A to 15D , it can be seen that the display system given in Example 2 can achieve good imaging quality in the fourth state.

[0135] Figure 16AThe axial chromatic aberration curve of the display system according to Embodiment 2 in the fifth state is shown, which represents the deviation of the converging point of the light with a wavelength of 555 nm after passing through the display system. Figure 16B The astigmatism curve of the display system according to Embodiment 2 in the fifth state is shown, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 16C The distortion curve of the display system according to Embodiment 2 in the fifth state is shown, which represents the distortion magnitude values corresponding to different field angles of view. Figure 16D The modulation transfer function curve of the display system according to Embodiment 2 in the fifth state is shown. According to Figures 16A to 16D it can be known that the display system given in Embodiment 2 can achieve good imaging quality in the fifth state.

[0136] Example 3

[0137] The following refers to Figures 17 to 21 , Figures 22A to 22D , Figures 23A to 23D , Figures 24A to 24D to describe the display system of Embodiment 3.

[0138] As Figures 17 to 21 shown, the display system may include a stop STO, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, and a partially reflective element BS arranged in sequence along the optical axis from the first side to the second side. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side surface of each element is referred to as the near-human-eye side surface, and the second side surface is referred to as the near-screen side surface.

[0139] The first lens E1 has a positive optical power, its near-human-eye side surface S1 is a convex surface, and its near-screen side surface S2 is a flat surface. The reflective polarizing element RP has a near-human-eye side surface and a near-screen side surface S3, and the near-human-eye side surface of the reflective polarizing element RP is attached to the near-screen side surface S2 of the first lens E1. The quarter-wave plate QWP has a near-human-eye side surface and a near-screen side surface S4, and the near-human-eye side surface of the quarter-wave plate QWP is attached to the near-screen side surface S3 of the reflective polarizing element RP. The second lens E2 has a positive optical power, its near-human-eye side surface S5 is a convex surface, and its near-screen side surface S6 is a convex surface. The partially reflective element BS is attached to the near-screen side surface S6 of the second lens E2.

[0140] In this example, an image surface IMG may be provided on the second side of the display system, and a display screen may be provided on the image surface IMG. After the image light from the image surface IMG sequentially passes through the second lens E2, the quarter-wave plate QWP, and reaches the reflective polarizing element RP, the first reflection occurs at the reflective polarizing element RP. The light reflected for the first time passes through the quarter-wave plate QWP, the second lens E2, and reaches the partial reflection element BS on the near-screen side of the second lens E2, and the second reflection occurs at the partial reflection element BS. The light reflected for the second time sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture (such as the user's eye pupil) and finally forms an image at a predetermined position. For example, the light after two reflections of the display system is finally projected into the user's eye pupil. A protective glass E3 may also be provided between the image surface IMG and the second lens E2.

[0141] Table 7 shows the basic parameter table of the display system of Embodiment 3, where the unit of the radius of curvature and the thickness / distance is millimeter (mm).

[0142]

[0143]

[0144] Table 7

[0145] In this embodiment, the display system has a first state (abbreviated as a), a second state (abbreviated as b), a third state (abbreviated as c), a fourth state (abbreviated as d), and a fifth state (abbreviated as e). Among them, the virtual image distance of the display system is D1, the central thickness of the second lens on the optical axis is D2, the radius of curvature of the first side of the second lens is W1, the radius of curvature of the second side of the second lens is W2, and D1, D2, W1, and W2 are variables, which may change with the change of the display system state.

[0146] Table 8 shows the values of D1, D2, W1, W2, f2, and f in different states of the display system of Embodiment 3.

[0147] Status a b c d e D1 (mm) -1300 -500 -333.33 -250 -5000 D2 (mm) 6.50 6.5568 6.2777 5.9721 6.9414 W1 (mm) 349.23 150.45 132.72 122.10 230.98 W2 (mm) -78.05 -91.44 -93.57 -94.64 -84.74 f2 (mm) 196.63 175.82 169.68 164.84 191.41 f (mm) 22.02 22.99 22.89 22.71 22.86

[0148] Table 8

[0149] In this embodiment, the near-eye side S1 of the first lens E1 is an aspherical surface. Table 9 gives the higher-order term coefficients A4, A6, A8, A 10 、A 12 、A 14 、A 16 、A 18 and A 20 .

[0150] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -6.8E-06 1.3E-08 -2.8E-11 3.4E-14 -1.8E-17 0.0E+00 0.0E+00 0.0E+00 0.0E+00

[0151] Table 9

[0152] Figure 22A shows the axial chromatic aberration curve of the display system in Embodiment 3 in the first state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 22B shows the astigmatism curve of the display system in Embodiment 3 in the first state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 22C shows the distortion curve of the display system in Embodiment 3 in the first state, which represents the distortion magnitude values corresponding to different field angles of view. Figure 22D shows the modulation transfer function curve of the display system in Embodiment 3 in the first state. According to Figures 22A to 22D it can be known that the display system given in Embodiment 3 can achieve good imaging quality in the first state.

[0153] Figure 23A shows the axial chromatic aberration curve of the display system in Embodiment 3 in the fourth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 23B shows the astigmatism curve of the display system in Embodiment 3 in the fourth state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 23C shows the distortion curve of the display system in Embodiment 3 in the fourth state, which represents the distortion magnitude values corresponding to different field angles of view. Figure 23D shows the modulation transfer function curve of the display system in Embodiment 3 in the fourth state. According to Figures 23A to 23D it can be known that the display system given in Embodiment 3 can achieve good imaging quality in the fourth state.

[0154] Figure 24A shows the axial chromatic aberration curve of the display system in Embodiment 3 in the fifth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 24B shows the astigmatism curve of the display system in Embodiment 3 in the fifth state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 24C shows the distortion curve of the display system in Embodiment 3 in the fifth state, which represents the distortion magnitude values corresponding to different field angles of view. Figure 24D shows the modulation transfer function curve of the display system in Embodiment 3 in the fifth state. According to Figures 24A to 24D it can be known that the display system given in Embodiment 3 can achieve good imaging quality in the fifth state.

[0155] Example 4

[0156] Refer to the following Figures 25 to 29 , Figures 30A to 30D , Figures 31A to 31D , Figures 32A to 32D to describe the display system of Example 4.

[0157] As Figures 25 to 29 shown, the display system may include a stop STO, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, and a partially reflective element BS arranged in sequence along the optical axis from the first side to the second side. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element is referred to as the near-human-eye side, and the second side is referred to as the near-screen side.

[0158] The first lens E1 has a positive optical power, its near-human-eye side S1 is concave, and its near-screen side S2 is convex. The reflective polarizing element RP has a near-human-eye side and a near-screen side S3, and the near-human-eye side of the reflective polarizing element RP is attached to the near-screen side S2 of the first lens E1. The quarter-wave plate QWP has a near-human-eye side and a near-screen side S4, and the near-human-eye side of the quarter-wave plate QWP is attached to the near-screen side S3 of the reflective polarizing element RP. The second lens E2 has a positive optical power, its near-human-eye side S5 is concave, and its near-screen side S6 is convex. The partially reflective element BS is attached to the near-screen side S6 of the second lens E2.

[0159] In this example, an image plane IMG may be provided on the second side of the display system, and a display screen may be provided on the image plane IMG. After the image light from the image plane IMG sequentially passes through the second lens E2, the quarter-wave plate QWP, and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. The light after the first reflection passes through the quarter-wave plate QWP, the second lens E2, and reaches the partially reflective element BS located on the near-screen side of the second lens E2, where a second reflection occurs at the partially reflective element BS. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture (such as the user's eye pupil) and finally forms an image at a predetermined position. For example, the light after two reflections of this display system is finally projected into the user's eye pupil. A protective glass E3 may also be provided between the image plane IMG and the second lens E2.

[0160] Table 10 shows the basic parameter table of the display system of Example 4, where the unit of the radius of curvature and the thickness / distance is millimeter (mm).

[0161]

[0162]

[0163] Table 10

[0164] In this embodiment, the display system has a first state (abbreviated as a), a second state (abbreviated as b), a third state (abbreviated as c), a fourth state (abbreviated as d), and a fifth state (abbreviated as e). Among them, the virtual image distance of the display system is D1, the central thickness of the second lens on the optical axis is D2, the radius of curvature of the first side of the second lens is W1, the radius of curvature of the second side of the second lens is W2, and D1, D2, W1, and W2 are variables that can change with the change of the state of the display system.

[0165] Table 11 shows the values of D1, D2, W1, W2, f2, and f in different states of the display system in Embodiment 4.

[0166] Status a b c d e D1 (mm) -1300 -500 -333.33 -250 -5000 D2 (mm) 6.50 6.0856 5.7103 5.3355 6.7516 W1 (mm) -142.27 -154.82 -165.60 -177.41 -137.82 W2 (mm) -47.55 -47.58 -47.43 -47.26 -47.74 f2 (mm) 215.67 208.01 201.73 195.85 220.26 f (mm) 24.97 24.99 24.90 24.78 25.09

[0167] Table 11

[0168] In this embodiment, the near-eye side S1 of the first lens E1 is an aspherical surface. Table 12 gives the higher-order term coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 , and A 20 of the aspherical surface S1 that can be used in Embodiment 4.

[0169] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.1E-06 4.9E-09 -2.6E-11 7.9E-14 -1.2E-16 0.0E+00 0.0E+00 0.0E+00 0.0E+00

[0170] Table 12

[0171] Figure 30A shows the axial chromatic aberration curve of the display system in Embodiment 4 in the first state, which represents the deviation of the focus point of the light with a wavelength of 555 nm after passing through the display system. Figure 30B shows the astigmatism curve of the display system in Embodiment 4 in the first state, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 30C shows the distortion curve of the display system in Embodiment 4 in the first state, which represents the distortion magnitude values corresponding to different field angles. Figure 30D shows the modulation transfer function curve of the display system in Embodiment 4 in the first state. According to Figures 30A to 30D It can be seen that the display system given in Embodiment 4 can achieve good imaging quality in the first state.

[0172] Figure 31AShows the axial chromatic aberration curve of the display system of Embodiment 4 in the fourth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 31B Shows the astigmatism curve of the display system of Embodiment 4 in the fourth state, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 31C Shows the distortion curve of the display system of Embodiment 4 in the fourth state, which represents the distortion magnitude values corresponding to different field angles. Figure 31D Shows the modulation transfer function curve of the display system of Embodiment 4 in the fourth state. According to Figures 31A to 31D it can be seen that the display system given in Embodiment 4 can achieve good imaging quality in the fourth state.

[0173] Figure 32A Shows the axial chromatic aberration curve of the display system of Embodiment 4 in the fifth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 32B Shows the astigmatism curve of the display system of Embodiment 4 in the fifth state, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles. Figure 32C Shows the distortion curve of the display system of Embodiment 4 in the fifth state, which represents the distortion magnitude values corresponding to different field angles. Figure 32D Shows the modulation transfer function curve of the display system of Embodiment 4 in the fifth state. According to Figures 32A to 32D it can be seen that the display system given in Embodiment 4 can achieve good imaging quality in the fifth state.

[0174] Example 5

[0175] The following refers to Figures 33 to 37 、 Figures 38A to 38D 、 Figures 39A to 39D 、 Figures 40A to 40D to describe the display system of Embodiment 5.

[0176] As Figures 33 to 37 shown, the display system may include a stop STO, a first lens E1, a reflective polarizing element RP, a quarter-wave plate QWP, a second lens E2, and a partially reflective element BS arranged in sequence along the optical axis from the first side to the second side. In this embodiment, the first side refers to the human eye side, and the second side refers to the display screen side. The first side of each element is referred to as the near-eye side, and the second side is referred to as the near-screen side.

[0177] The first lens E1 has a positive focal power. Its side S1 close to the human eye is concave, and its side S2 close to the screen is convex. The reflective polarizing element RP has a side close to the human eye and a side S3 close to the screen. The side of the reflective polarizing element RP close to the human eye is attached to the side S2 of the first lens E1 close to the screen. The quarter-wave plate QWP has a side close to the human eye and a side S4 close to the screen. The side of the quarter-wave plate QWP close to the human eye is attached to the side S3 of the reflective polarizing element RP close to the screen. The second lens E2 has a positive focal power. Its side S5 close to the human eye is concave, and its side S6 close to the screen is convex. The partial reflection element BS is attached to the side S6 of the second lens E2 close to the screen.

[0178] In this example, an image plane IMG can be provided on the second side of the display system. The image plane IMG can be provided with a display screen. After the image light from the image plane IMG sequentially passes through the second lens E2, the quarter-wave plate QWP and reaches the reflective polarizing element RP, a first reflection occurs at the reflective polarizing element RP. The light after the first reflection passes through the quarter-wave plate QWP, the second lens E2 and reaches the partial reflection element BS located on the side of the second lens E2 close to the screen, and a second reflection occurs at the partial reflection element BS. The light after the second reflection sequentially passes through the second lens E2, the quarter-wave plate QWP, the reflective polarizing element RP, the first lens E1 to the aperture (such as the user's eye pupil) and finally forms an image at a predetermined position. For example, the light after two reflections of the display system is finally projected into the user's eye pupil. A protective glass E3 can also be provided between the image plane IMG and the second lens E2.

[0179] Table 13 shows the basic parameter table of the display system in Embodiment 5, where the unit of the radius of curvature and the thickness / distance is millimeter (mm).

[0180]

[0181] Table 13

[0182] In this embodiment, the display system has a first state (abbreviated as a), a second state (abbreviated as b), a third state (abbreviated as c), a fourth state (abbreviated as d) and a fifth state (abbreviated as e). Among them, the virtual image distance of the display system is D1, the central thickness of the second lens on the optical axis is D2, the radius of curvature of the first side of the second lens is W1, the radius of curvature of the second side of the second lens is W2, and D1, D2, W1 and W2 are variables, which can change with the change of the state of the display system.

[0183] Table 14 shows the values of D1, D2, W1, W2, f2 and f in different states of the display system in Embodiment 5.

[0184] Status a b c d e D1 (mm) -1300 -500 -333.33 -250 -5000 D2 (mm) 6.4184 6.0182 5.6497 5.2819 6.6700 W1 (mm) -158.84 -174.43 -186.25 -198.58 -154.59 W2 (mm) -51.29 -51.48 -51.38 -51.24 -51.50 f2 (mm) 165.23 159.82 155.62 151.75 168.21 f (mm) 22.83 22.78 22.63 22.47 22.98

[0185] Table 14

[0186] In this embodiment, the side S1 of the first lens E1 close to the human eye is an aspherical surface. Table 15 gives the higher-order coefficients A4, A6, A8, A 10 , A 12 , A 14 , A 16 , A 18 and A 20 of the aspherical surface S1 that can be used in Embodiment 5.

[0187] Face number A4 A6 A8 A10 A12 A14 A16 A18 A20 S1 -2.6E-06 6.4E-09 -2.9E-11 6.3E-14 -6.4E-17 0.0E+00 0.0E+00 0.0E+00 0.0E+00

[0188] Table 15

[0189] Figure 38A shows the axial chromatic aberration curve of the display system of Embodiment 5 in the first state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 38B shows the astigmatism curve of the display system of Embodiment 5 in the first state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 38C shows the distortion curve of the display system of Embodiment 5 in the first state, which represents the distortion magnitude values corresponding to different field angles of view. Figure 38D shows the modulation transfer function curve of the display system of Embodiment 5 in the first state. According to Figures 38A to 38D , it can be seen that the display system given in Embodiment 5 can achieve good imaging quality in the first state.

[0190] Figure 39A shows the axial chromatic aberration curve of the display system of Embodiment 5 in the fourth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 39B shows the astigmatism curve of the display system of Embodiment 5 in the fourth state, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different field angles of view. Figure 39C shows the distortion curve of the display system of Embodiment 5 in the fourth state, which represents the distortion magnitude values corresponding to different field angles of view. Figure 39D shows the modulation transfer function curve of the display system of Embodiment 5 in the fourth state. According to Figures 39A to 39D , it can be seen that the display system given in Embodiment 5 can achieve good imaging quality in the fourth state.

[0191] Figure 40A shows the axial chromatic aberration curve of the display system of Embodiment 5 in the fifth state, which represents the deviation of the convergence point of the light with a wavelength of 555 nm after passing through the display system. Figure 40BThe astigmatism curve of the display system of Embodiment 5 in the fifth state is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different field angles of view. Figure 40C The distortion curve of the display system of Embodiment 5 in the fifth state is shown, which represents the distortion magnitude values corresponding to different field angles of view. Figure 40D The modulation transfer function curve of the display system of Embodiment 5 in the fifth state is shown. According to Figures 40A to 40D it can be known that the display system given in Embodiment 5 can achieve good imaging quality in the fifth state.

[0192] Table 16 gives the basic parameters of each of Embodiments 1 to 5, such as the values of TTLa, FG1, FNOa, FNOb, FNOc, FNOd, and FNOe.

[0193]

[0194]

[0195] Table 16

[0196] Table 17 shows the values of the conditional expressions of each of Embodiments 1 to 5.

[0197]

[0198] Table 17

[0199] This application also provides an optical device, which can be an independent projection device such as a projector, or a projection module integrated on a mobile electronic device such as a virtual reality device. The optical device is equipped with the display system described above.

[0200] The above description is only the preferred embodiments of this application and the explanation of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above technical features, and 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 technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A display system, characterized in that, It sequentially includes a diaphragm, a first lens with positive optical power, a reflective polarizing element, a quarter-wave plate, a second lens with positive optical power, and a partial reflection element along the optical axis from the first side to the second side; the reflective polarizing element is used to reflect the image light from the second side to form a first reflected image light; the partial reflection element is used to reflect the first reflected image light to form a second reflected image light; The reflective polarizing element is attached to and adhered to the second side surface of the first lens in contact with the quarter-wave plate; The second lens is configured as a variable focal length lens; The number of lenses with optical power in the display system is two; The display system has multiple states, and the virtual image distances in different states of the display system are different. The virtual image distance is the axial distance from the virtual image formed by the image light from the second side at a predetermined position to the diaphragm; The display system satisfies: -5000mm ≤ VID ≤ -250mm, where VIDn is the virtual image distance of the display system.

2. The display system according to claim 1, characterized in that, The partial reflection element is disposed on the second side surface of the second lens; the second side surface of the second lens is a convex surface; The display system satisfies: 1.3 < N2 < 1.5, where N2 is the refractive index of the second lens.

3. The display system according to claim 1, wherein The display system satisfies: 1.1 < f2e / f2d < 1.35, where f2e is the effective focal length of the second lens in the fifth state, and f2d is the effective focal length of the second lens in the fourth state.

4. The display system according to claim 1, wherein The display system satisfies: 1.25 < |R3n / R4n| < 4.5, n = a, b, c, d, e, where when n = a, R3n is the curvature radius of the first side surface of the second lens in the first state, and R4n is the curvature radius of the second side surface of the second lens in the first state; when n = b, R3n is the curvature radius of the first side surface of the second lens in the second state, and R4n is the curvature radius of the second side surface of the second lens in the second state; when n = c, R3n is the curvature radius of the first side surface of the second lens in the third state, and R4n is the curvature radius of the second side surface of the second lens in the third state; when n = d, R3n is the curvature radius of the first side surface of the second lens in the fourth state, and R4n is the curvature radius of the second side surface of the second lens in the fourth state; when n = e, R3n is the curvature radius of the first side surface of the second lens in the fifth state, and R4n is the curvature radius of the second side surface of the second lens in the fifth state.

5. The display system according to claim 1, wherein The display system satisfies: 0.2 < |FG1 / f2d| < 1.8, where FG1 is the combined focal length of the first lens, the reflective polarizing element, and the quarter-wave plate, and f2d is the effective focal length of the second lens in the fourth state.

6. The display system according to claim 1, wherein The display system satisfies: 2.7 < (CT2e - CT2d) / (fe - fd) < 8.85, Wherein, CT2e is the central thickness of the second lens on the optical axis in the fifth state, CT2d is the central thickness of the second lens on the optical axis in the fourth state, fe is the total effective focal length of the display system in the fifth state, and fd is the total effective focal length of the display system in the fourth state.

7. The display system according to any one of claims 1-6, characterized in that, The display system satisfies: 22mm < fn < 25.1mm, n = a, b, c, d, e, Wherein, when n = a, fn is the total effective focal length of the display system in the first state; when n = b, fn is the total effective focal length of the display system in the second state; when n = c, fn is the total effective focal length of the display system in the third state; when n = d, fn is the total effective focal length of the display system in the fourth state; when n = e, fn is the total effective focal length of the display system in the fifth state.

8. The display system according to any one of claims 1-6, characterized in that, The display system satisfies: 5.4 < FNOn < 6.3, n = a, b, c, d, e, Wherein, when n = a, FNOn is the f-number of the display system in the first state; when n = b, FNOn is the f-number of the display system in the second state; when n = c, FNOn is the f-number of the display system in the third state; when n = d, FNOn is the f-number of the display system in the fourth state; when n = e, FNOn is the f-number of the display system in the fifth state.

9. The display system according to any one of claims 1-6, characterized in that, The display system satisfies: 3.8 < TTLa / fa × FNOa < 4.6, Wherein, TTLa is the on-axis distance from the first side surface of the first lens to the image plane of the display system in the first state, fa is the total effective focal length of the display system in the first state, and FNOa is the f-number of the display system in the first state.

10. The display system according to any one of claims 1-6, characterized in that, The display system satisfies: 13mm < EYEBOX < 17mm, Wherein, EYEBOX is the on-axis distance from the diaphragm to the first side surface of the first lens.

Images