A projection lens and display system

Abstract

The application discloses a projection lens and a display system. The projection lens comprises a display device, a lens assembly and an aperture stop arranged in sequence along a preset direction. The lens assembly comprises a plurality of lenses arranged along the preset direction. Wherein, 6mm≤f≤10mm, 26°≤FOV≤40°, 3mm≤h≤6mm, 4mm≤R≤10mm, 9mm≤L≤15mm. f is the focal length of the lens assembly, FOV is the field of view of the lens assembly, h is the aperture of the aperture stop, R is the aperture of the lens assembly, and L is the distance between the display device and the aperture stop along the preset direction AA. By reasonably designing the parameters of the lens assembly and the aperture stop, and adjusting the distance between the lens assembly and the aperture stop, various aberrations of the projection lens can be effectively corrected, the projection lens has the advantages of high resolution and small optical distortion, and the requirements of high resolution and high-quality imaging of the AR display device can be met.

Description

Technical Field

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

[0002] Augmented Reality (AR) display devices mainly consist of a projection lens and an optical waveguide device. The projection lens magnifies the image source of the display device to form a virtual image at a certain distance, and then projects it onto the retina through the optical waveguide device.

[0003] However, projection lenses in related technologies generally suffer from low resolution, making it difficult to meet the needs of AR display devices. Summary of the Invention

[0004] This application provides a projection lens and display system, which enables the projection lens to have high resolution, thus meeting the needs of AR display devices.

[0005] In a first aspect, this application provides a projection lens, comprising: a lens assembly including a plurality of lenses arranged along a preset direction, the preset direction being parallel to the optical axis of the lens assembly; a display device arranged along the preset direction with the lens assembly, the display device being used to emit light toward the lens assembly; and an aperture stop arranged along the preset direction with the lens assembly and located on the side of the lens assembly away from the display device; wherein, 6 mm ≤ f ≤ 10 mm, 26 degrees ≤ FOV ≤ 40 degrees, 3 mm ≤ h ≤ 6 mm, 4 mm ≤ R ≤ 10 mm, 9 mm ≤ L ≤ 15 mm; f is the focal length of the lens assembly, FOV is the field of view of the lens assembly, h is the aperture of the aperture stop, R is the aperture diameter of the lens assembly, and L is the distance between the display device and the aperture stop along the preset direction AA.

[0006] In some embodiments of this application, the lens assembly includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the preset direction. The first lens is located between the second lens and the display device. Specifically: the first lens has a planar light-incident surface and a concave light-outcident surface, with negative optical power; the second lens has a convex light-incident surface and a convex light-outcident surface, with positive optical power; the third lens has a convex light-incident surface and a convex light-outcident surface, with positive optical power; the fourth lens has a concave light-incident surface and a concave light-outcident surface, with negative optical power; and the fifth lens has a planar light-incident surface and a convex light-outcident surface, with positive optical power. The lens assembly can be composed of only five lenses. By combining different lenses and rationally allocating the optical power of each lens, the number of lenses can be reduced while maintaining the advantages of high resolution and low optical distortion in the projection lens. This simplifies the structure of the lens assembly and reduces the overall size and weight of the projection lens.

[0007] In some embodiments of this application, each lens in the lens assembly satisfies the following conditions: -15 mm ≤ f1 ≤ -5 mm, 0.5 mm ≤ T1 ≤ 1.2 mm, 1.8 ≤ n1 ≤ 2.0, 18 ≤ v1 ≤ 35; 3 mm ≤ f2 ≤ 20 mm, 1 mm ≤ T2 ≤ 1.8 mm, 1.8 ≤ n2 ≤ 2.0, 35 ≤ v2 ≤ 50; 3 mm ≤ f3 ≤ 15 mm, 1 mm ≤ T3 ≤ 2 mm, 1.8 ≤ n3 ≤ 2.0, 35 ≤ v3 ≤ 50; -15 mm ≤ f4 ≤ -3 mm, 0.5 mm ≤ T4 ≤ 1 mm, 1.8 ≤ n4 ≤ 2.0, 18 ≤ v4 ≤ 35; 3 mm ≤ f5 ≤ 20 mm, 0.8 mm ≤ T5 ≤ 1.5 mm, 1.8 ≤ n5 ≤ 2.0. 35≤v5≤50; where f1 is the focal length of the first lens, T1 is the thickness of the first lens, n1 is the refractive index of the first lens, and v1 is the Abbe constant of the first lens; f2 is the focal length of the second lens, T2 is the thickness of the second lens, n2 is the refractive index of the second lens, and v2 is the Abbe constant of the second lens; f3 is the focal length of the third lens, T3 is the thickness of the third lens, n3 is the refractive index of the third lens, and v3 is the Abbe constant of the third lens; f4 is the focal length of the fourth lens, T4 is the thickness of the fourth lens, n4 is the refractive index of the fourth lens, and v4 is the Abbe constant of the fourth lens; f5 is the focal length of the fifth lens, T5 is the thickness of the fifth lens, n5 is the refractive index of the fifth lens, and v5 is the Abbe constant of the fifth lens. By rationally allocating the parameters of each lens, the parameters of the lens assembly formed by combining multiple lenses can meet the requirements.

[0008] In some embodiments of this application, the display device includes a plurality of light-emitting units spaced apart on an emitting surface, the emitting surface being perpendicular to the preset direction. The small size of the light-emitting units provides excellent directivity, enabling them to emit light directionally and directly onto the surface of the illuminated object, resulting in high light utilization. Furthermore, the small size and light weight of the light-emitting units reduce the overall weight of the projection lens.

[0009] In some embodiments of this application, each lens in the lens assembly is made of optical glass. Compared with optical plastic, optical glass has better thermal stability. Display devices dissipate a lot of heat during operation, which affects the optical power and surface shape of optical plastic lenses. However, due to its good thermal stability, the surface shape and optical power of optical glass lenses are less prone to change, thus ensuring the optical performance stability of the projection lens.

[0010] In some embodiments of this application, at least one lens in the lens assembly has a spherical incident surface and an emitting surface. Spherical lenses are easier and less expensive to manufacture, which can reduce the manufacturing difficulty and cost of the lens assembly.

[0011] In some embodiments of this application, the incident surface and / or exit surface of at least one lens in the lens assembly is aspherical. Compared to a regular sphere, the design of aspherical surfaces allows different regions of the lens to have different optical properties, thereby enabling more functions.

[0012] In some embodiments of this application, the incident and / or exit surfaces of each lens in the lens assembly are provided with an anti-reflection coating. The anti-reflection coating can improve light transmittance, thereby improving the light efficiency of the lens assembly.

[0013] In some embodiments of this application, the aperture stop is located on the object-side focal plane of the lens assembly. This makes the projection lens an image-side telecentric lens, so that the main rays emitted by the display device at different field of view angles pass through the aperture stop and are parallel to the optical axis of the lens assembly. This maximizes the utilization of the light energy emitted by the display device in the direction perpendicular to the optical axis, thereby improving the light energy utilization rate of the projection lens.

[0014] Secondly, this application also provides a display system, including an optical waveguide device and a projection lens as described in any of the above embodiments; wherein the optical waveguide device and the projection lens are arranged along the preset direction, and the optical waveguide device is located on the light-emitting surface side of the projection lens.

[0015] The beneficial effects of this application are as follows: by rationally designing the parameters of the lens assembly and the aperture stop, and by adjusting the distance between the lens assembly and the aperture stop, various aberrations of the projection lens can be effectively corrected, so that the projection lens has the advantages of high resolution and low optical distortion, thereby meeting the requirements of high resolution and high quality imaging of AR display devices. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments or related technologies of this application, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the projection lens structure in one embodiment of this application;

[0018] Figure 2 This is a modulation transfer function curve of the projection lens in one embodiment of this application;

[0019] Figure 3 This is a field curvature curve diagram of the projection lens in one embodiment of this application;

[0020] Figure 4 This is an optical distortion curve of a projection lens in one embodiment of this application;

[0021] Figure 5 This is a schematic diagram of the structure of a display system in one embodiment of this application.

[0022] Figure label:

[0023] 10. Lens assembly; 20. First lens; 30. Second lens; 40. Third lens; 50. Fourth lens; 60. Fifth lens; 70. Display device; 71. Light-emitting unit; 80. Aperture stop; 90. Optical waveguide device. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0025] This application provides a projection lens and display system to solve the problem that projection lenses in related technologies generally have low resolution, making it difficult to meet the needs of AR display devices.

[0026] Firstly, this application provides a projection lens, such as Figure 1As shown, the projection lens includes a lens assembly 10, a display device 70, and an aperture stop 80.

[0027] The lens assembly 10 includes multiple lenses arranged along a preset direction AA, which is parallel to the optical axis of the lens assembly 10. The lenses can be made of optically transparent materials such as glass or resin, and each lens has one or more curved surfaces. They can change the direction of light propagation and control the light distribution to converge the light and ultimately form an image. The specific working principle of the lenses has been disclosed in related technologies and will not be elaborated upon here. To enable the lens assembly 10 to have various optical properties, the number of lenses in this application is set to multiple, and these lenses can be stacked together along the preset direction AA. The optical axis of the lens assembly 10 is the line passing through the center of each lens. Lenses can be classified as convex lenses or concave lenses according to their shape and function. Regardless of whether the lens is convex or concave, light rays incident on the lens along its optical axis will not undergo any change in optical properties; that is, the light rays will continue to propagate in the original direction.

[0028] The display device 70 and the lens assembly 10 are arranged along the preset direction AA. The display device 70 is used to emit light to the lens assembly 10. The light emitted by the display device 70 enters the lens assembly 10 from the light-incident side, and then the light is adjusted by the lens assembly 10 and exits from the light-exit side of the lens assembly 10 to form an imaging beam.

[0029] The aperture stop 80 and the lens assembly 10 are arranged along the preset direction AA and are located on the light-emitting side of the lens assembly 10. The imaging beam emitted from the lens assembly 10 exits through the hole in the aperture stop 80, and the size of the imaging beam can be adjusted using the aperture stop 80. The specific working principle of the aperture stop 80 has been disclosed in related technologies and will not be described in detail here.

[0030] Wherein, 6 mm ≤ f ≤ 10 mm, 26 degrees ≤ FOV ≤ 40 degrees, 3 mm ≤ h ≤ 6 mm, 4 mm ≤ R ≤ 10 mm, 9 mm ≤ L ≤ 15 mm; f is the focal length of the lens assembly 10, FOV is the field of view of the lens assembly 10, h is the aperture of the aperture stop 80, R is the diameter of the lens assembly 10, and L is the distance between the display device 70 and the aperture stop 80 along the preset direction AA.

[0031] It should be noted that the function of the lens assembly 10 is to magnify the image source displayed by the display device 70 and form a virtual image at a certain distance. By reasonably designing the parameters of the lens assembly 10 and the aperture stop 80, and by adjusting the distance between the lens assembly 10 and the aperture stop 80, various aberrations of the projection lens can be effectively corrected, so that the projection lens has the advantages of high resolution and low optical distortion, thereby meeting the requirements of high resolution and high quality imaging of AR display devices.

[0032] In one embodiment of this application, the focal length f of the lens assembly 10 can be 6.4 mm, the field of view (FOV) of the lens assembly 10 can be 28 degrees, the aperture h of the aperture stop 80 can be 4 mm, the aperture R of the lens assembly 10 can be 6 mm, and the distance L between the display device 70 and the aperture stop 80 along the preset direction AA can be 11.5 mm, so that the projection lens has higher resolution and less optical distortion.

[0033] See also Figure 1 As shown, in some embodiments of this application, at least one lens in the lens assembly 10 has a spherical light-incident surface and a spherical light-outcident surface.

[0034] In this case, only one lens may have a spherical light-incident surface and a spherical light-outcident surface, or multiple lenses may have spherical light-incident surfaces and spherical light-outcident surfaces. Spherical lenses have lower processing difficulty and cost, which can reduce the processing difficulty and manufacturing cost of lens assembly 10.

[0035] Of course, the incident surface and / or exit surface of at least one lens in the lens assembly 10 can also be aspherical. An aspherical surface refers to a shape other than a sphere, such as an irregular curved surface or a convex or concave surface composed of multiple planes. Compared with a regular sphere, the design of aspherical surfaces can make different regions of the lens have different optical properties, thereby enabling more functions.

[0036] Among them, only one lens may have an aspherical light-incident surface and / or an aspherical light-outcident surface, or multiple lenses may have aspherical light-incident surfaces and / or an aspherical light-outcident surfaces.

[0037] See also Figure 1 As shown in some embodiments of this application, the light-incident surface and / or light-outcident surface of each lens in the lens assembly 10 is provided with an anti-reflection coating. The anti-reflection coating can improve light transmittance, thereby improving the light efficiency of the lens assembly 10. The anti-reflection coating can be a single-layer anti-reflection coating or a multi-layer anti-reflection coating.

[0038] See also Figure 1As shown, in some embodiments of this application, the aperture stop 80 is located on the object-side focal plane of the lens assembly 10, making the projection lens an image-side telecentric lens. This ensures that the main rays emitted from the display device 70 at different field-of-view angles pass through the aperture stop 80 and are parallel to the optical axis of the lens assembly 10, maximizing the utilization of light energy emitted by the display device 70 in the direction perpendicular to the optical axis, thereby improving the light energy utilization rate of the projection lens. The specific definition of the object-side focal plane has been disclosed in related technologies and will not be elaborated upon here.

[0039] like Figure 5 As shown, in some embodiments of this application, the display device 70 includes a plurality of light-emitting units 71 spaced apart on an emitting surface, the emitting surface being perpendicular to the preset direction AA. Each light-emitting unit 71 can emit light toward the lens assembly 10. The display device 70 is constructed using a plurality of smaller light-emitting units 71. The light-emitting units 71 have good directivity, they can emit light in a directional manner and directly illuminate the surface of the object being illuminated, resulting in high light utilization. Furthermore, the light-emitting units 71 are small in size and light in weight, which can reduce the overall weight of the projection lens.

[0040] The multiple light-emitting units 71 can be arranged in an array or scattered. The light-emitting units 71 can be display devices 70 such as Micro LED (micro light-emitting diode) or Micro OLED (micro organic light-emitting diode).

[0041] See also Figure 1 As shown, in some embodiments of this application, the lens assembly 10 can be made of optical glass. Compared with optical plastic, optical glass has better thermal stability. The display device 70 dissipates a lot of heat during operation, which affects the optical power and surface shape of optical plastic lenses. However, due to its good thermal stability, the surface shape and optical power of optical glass lenses are less likely to change, thus ensuring the optical performance stability of the projection lens.

[0042] It should also be noted that, especially when the display device 70 is composed of multiple light-emitting units 71, the brightness of the display device 70 is greater and may dissipate more heat. Using optical glass for the lens can ensure the optical performance stability of the projection lens while ensuring the performance of the display device 70.

[0043] See also Figure 1 As shown, in some embodiments of this application, the lens assembly 10 includes a first lens 20, a second lens 30, a third lens 40, a fourth lens 50, and a fifth lens 60 arranged sequentially along the preset direction AA, wherein the first lens 20 is located between the second lens 30 and the display device 70; wherein:

[0044] The light-incident surface of the first lens 20 is a plane, the light-outceasing surface is a concave surface, and the optical power is negative;

[0045] The light-incident surface of the second lens 30 is convex, the light-outcrystal surface is convex, and the optical power is positive;

[0046] The light-incident surface of the third lens 40 is convex, the light-outcrystal surface is convex, and the optical power is positive.

[0047] The light-incident surface of the fourth lens 50 is concave, the light-outcrystal surface is concave, and the optical power is negative.

[0048] The fifth lens 60 has a planar incident surface, a convex exit surface, and a positive optical power.

[0049] It should be noted that the lens assembly 10 can be composed of only 5 lenses. By combining different lenses and rationally allocating the optical power of each lens, the number of lenses can be reduced while maintaining the advantages of high resolution and low optical distortion in the projection lens. This makes the structure of the lens assembly 10 simpler and reduces the overall size and weight of the projection lens.

[0050] Of course, while ensuring the performance of the lens assembly 10, the lens assembly 10 can also be composed of more or fewer lenses, such as the lens assembly 10 being composed of 4, 6 or other numbers of lenses.

[0051] The lenses in the lens assembly 10 can satisfy the following:

[0052] -15 mm ≤ f1 ≤ -5 mm, 0.5 mm ≤ T1 ≤ 1.2 mm, 1.8 ≤ n1 ≤ 2.0, 18 ≤ v1 ≤ 35;

[0053] 3 mm ≤ f2 ≤ 20 mm, 1 mm ≤ T2 ≤ 1.8 mm, 1.8 ≤ n2 ≤ 2.0, 35 ≤ v2 ≤ 50;

[0054] 3 mm ≤ f3 ≤ 15 mm, 1 mm ≤ T3 ≤ 2 mm, 1.8 ≤ n3 ≤ 2.0, 35 ≤ v3 ≤ 50;

[0055] -15 mm ≤ f4 ≤ -3 mm, 0.5 mm ≤ T4 ≤ 1 mm, 1.8 ≤ n4 ≤ 2.0, 18 ≤ v4 ≤ 35;

[0056] 3 mm ≤ f5 ≤ 20 mm, 0.8 mm ≤ T5 ≤ 1.5 mm, 1.8 ≤ n5 ≤ 2.0, 35 ≤ v5 ≤ 50;

[0057] f1 is the focal length of the first lens 20, T1 is the thickness of the first lens 20, n1 is the refractive index of the first lens 20, and v1 is the Abbe constant of the first lens 20; f2 is the focal length of the second lens 30, T2 is the thickness of the second lens 30, n2 is the refractive index of the second lens 30, and v2 is the Abbe constant of the second lens 30; f3 is the focal length of the third lens 40, T3 is the thickness of the third lens 40, n3 is the refractive index of the third lens 40, and v3 is the Abbe constant of the third lens 40; f4 is the focal length of the fourth lens 50, T4 is the thickness of the fourth lens 50, n4 is the refractive index of the fourth lens 50, and v4 is the Abbe constant of the fourth lens 50; f5 is the focal length of the fifth lens 60, T5 is the thickness of the fifth lens 60, n5 is the refractive index of the fifth lens 60, and v5 is the Abbe constant of the fifth lens 60.

[0058] It is understandable that the lens assembly 10 is formed by combining multiple lenses. By reasonably allocating the various parameters of each lens, the parameters of the lens assembly 10 formed by combining multiple lenses can meet the requirements.

[0059] In one embodiment of this application, the parameters of each lens in the lens assembly 10 can be shown in Table 1 below:

[0060]

[0061] Table 1

[0062] Wherein, S21 is the light-incident surface of the first lens 20, and S22 is the light-exiting surface of the first lens 20; S31 is the light-incident surface of the second lens 30, and S32 is the light-exiting surface of the second lens 30; S41 is the light-incident surface of the third lens 40, and S42 is the light-exiting surface of the second lens 30; S51 is the light-incident surface of the fourth lens 50, and S52 is the light-exiting surface of the fourth lens 50; S61 is the light-incident surface of the fifth lens 60, and S62 is the light-exiting surface of the fifth lens 60.

[0063] See Figures 2 to 4 As shown, Figure 2 This is a graph showing the modulation transfer function (MTF) curves of the projection lens when the parameters of each lens are the data in Table 1. Figure 2 The horizontal axis of the modulation transfer function curve represents the spatial resolution value, and the vertical axis represents the MTF value. The unit of spatial resolution is line pairs per millimeter. Figure 3 This is a field curvature curve of the projection lens when the parameters of each lens are the data in Table 1. Figure 3 The horizontal axis of the field curvature curve of the projection lens represents the field curvature value, and the vertical axis represents the field angle value. Figure 4 This is a graph showing the optical distortion of the projection lens when the parameters of each lens are as shown in Table 1. Figure 4 The horizontal axis of the optical distortion curve of the projection lens represents the optical distortion value, and the vertical axis represents the field of view value.

[0064] It should be noted that MTF reflects the resolving power of a projection lens and can be used to evaluate the image quality of a projection lens. It reflects the lens's ability to reproduce object details. At a higher spatial resolution, a larger MTF value indicates higher resolving power and better image quality. Figure 2 As can be seen from the data, the MTF value of the projection lens in this embodiment is greater than 0.5 at a spatial resolution of 125 line pairs / mm, which means that the projection lens in this embodiment has a very high resolution.

[0065] It should also be noted that field curvature causes a decrease in sharpness at the edges of the field of view relative to the center. A greater field curvature means a decrease in MTF (Mean Transmission Frequency), and the greater the field curvature, the greater the decrease in MTF. Figure 3 As can be seen from the embodiments of this application, the field curvature of the projection lens is between -0.05 mm and 0.05 mm, which is within a small range.

[0066] It should also be noted that the degree of optical distortion greatly affects the image quality of a projection lens. Figure 4 As can be seen from the above, the optical distortion of the projection lens in this embodiment is less than 0.2%, indicating that the distortion of the image projected by the projection lens in this embodiment is very small.

[0067] Based on the aforementioned projection lens, this application also provides a display system, such as... Figure 5 As shown, the display system includes an optical waveguide device 90 and a projection lens as described in any of the above embodiments.

[0068] The optical waveguide device 90 and the projection lens are arranged along the preset direction AA, and the optical waveguide device 90 is located on the light-emitting surface side of the projection lens.

[0069] It should be noted that the optical waveguide device 90 can transmit the light beam emitted from the projection lens. The size and specific type of the optical waveguide device 90 can be selected according to actual needs, and this application does not impose specific limitations.

[0070] The display system can be an AR display device, or it can be an electronic device such as a projector, wearable watch, mobile phone, or tablet. Taking an AR display device as an example, the light emitted by the display device 70 passes through the projection lens, which magnifies the image source displayed by the micro-display device 70. The light emitted from the projection lens propagates through the optical waveguide device 90 and exits near the eye, finally entering the human eye to form an image.

[0071] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A projection lens, characterized in that, include: A lens assembly includes a plurality of lenses arranged along a preset direction, the preset direction being parallel to the optical axis of the lens assembly; The lens assembly includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens arranged sequentially along the preset direction, wherein the first lens is located between the second lens and the display device; A display device is arranged along the preset direction with the lens assembly, and the display device is used to emit light to the lens assembly; An aperture stop is arranged along the preset direction with the lens assembly and is located on the side of the lens assembly away from the display device; Wherein, 6 mm ≤ f ≤ 10 mm, 26 degrees ≤ FOV ≤ 40 degrees, 3 mm ≤ h ≤ 6 mm, 4 mm ≤ R ≤ 10 mm, 9 mm ≤ L ≤ 15 mm; f is the focal length of the lens assembly, FOV is the field of view of the lens assembly, h is the aperture of the aperture stop, R is the diameter of the lens assembly, and L is the distance between the display device and the aperture stop along the preset direction AA. Each lens in the lens assembly satisfies the following: -15 mm ≤ f1 ≤ -5 mm, 0.5 mm ≤ T1 ≤ 1.2 mm, 1.8 ≤ n1 ≤ 2.0, 18 ≤ v1 ≤ 35; 3 mm ≤ f2 ≤ 20 mm, 1 mm ≤ T2 ≤ 1.8 mm, 1.8 ≤ n2 ≤ 2.0, 35 ≤ v2 ≤ 50; 3 mm ≤ f3 ≤ 15 mm, 1 mm ≤ T3 ≤ 2 mm, 1.8 ≤ n3 ≤ 2.0, 35 ≤ v3 ≤ 50; -15 mm ≤ f4 ≤ -3 mm, 0.5 mm ≤ T4 ≤ 1 mm, 1.8 ≤ n4 ≤ 2.0, 18 ≤ v4 ≤ 35; 3 mm ≤ f5 ≤ 20 mm, 0.8 mm ≤ T5 ≤ 1.5 mm, 1.8 ≤ n5 ≤ 2.0, 35 ≤ v5 ≤ 50; Where f1 is the focal length of the first lens, T1 is the thickness of the first lens, n1 is the refractive index of the first lens, and v1 is the Abbe constant of the first lens; f2 is the focal length of the second lens, T2 is the thickness of the second lens, n2 is the refractive index of the second lens, and v2 is the Abbe constant of the second lens; f3 is the focal length of the third lens, T3 is the thickness of the third lens, n3 is the refractive index of the third lens, and v3 is the Abbe constant of the third lens; f4 is the focal length of the fourth lens, T4 is the thickness of the fourth lens, n4 is the refractive index of the fourth lens, and v4 is the Abbe constant of the fourth lens; f5 is the focal length of the fifth lens, T5 is the thickness of the fifth lens, n5 is the refractive index of the fifth lens, and v5 is the Abbe constant of the fifth lens.

2. The projection lens according to claim 1, characterized in that, The first lens has a planar light-incident surface, a concave light-outcident surface, and a negative optical power. The second lens has a convex light-incident surface, a convex light-outceasing surface, and a positive optical power. The third lens has a convex light-incident surface, a convex light-outceasing surface, and a positive optical power. The fourth lens has a concave light-incident surface, a concave light-outcident surface, and a negative optical power. The fifth lens has a planar incident surface, a convex exit surface, and a positive optical power.

3. The projection lens according to claim 1, characterized in that, The display device includes a plurality of light-emitting units spaced apart on an emitting surface, the emitting surface being perpendicular to the preset direction.

4. The projection lens according to claim 1, characterized in that, The lenses in the lens assembly are all made of optical glass.

5. The projection lens according to claim 1, characterized in that, At least one lens in the lens assembly has a spherical incident surface and an emitting surface.

6. The projection lens according to claim 1, characterized in that, At least one lens in the lens assembly has an incident surface and / or an exit surface that is aspherical.

7. The projection lens according to claim 1, characterized in that, The light-incident surface and / or light-outcident surface of each lens in the lens assembly are provided with an anti-reflection coating.

8. The projection lens according to claim 1, characterized in that, The aperture stop is located on the object-side focal plane of the lens assembly.

9. A display system, characterized in that, Includes optical waveguide devices and a projection lens as described in any one of claims 1 to 8; The optical waveguide device and the projection lens are arranged along the preset direction, and the optical waveguide device is located on the light-emitting surface side of the projection lens.

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