Lens, projection device, display device and vehicle

Abstract

The embodiment of the invention provides a lens, a projection device, a display device and a vehicle, and belongs to the technical field of optics. The lens comprises a first lens and a fixed lens group. The first lens is closest to the image side and has positive focal power. The first lens is used for moving relative to the fixed lens group along the optical axis direction of the lens. The fixed lens group comprises a first lens group, a diaphragm and a second lens group. The first lens group is located between the first lens and the diaphragm. The first lens closest to the first lens in the first lens group has negative focal power, the second lens has negative focal power, and the third lens has positive focal power. In the second lens group, the first lens closest to the diaphragm has negative focal power, the second lens has positive focal power, the third lens has positive focal power, and the fourth lens has positive focal power. Through the arrangement, the definition and reliability of the lens are high, and the cost of the lens is reduced.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the optical technical field, in particular to a lens, a projection device, a display device and a vehicle. BACKGROUND

[0002] With the development of intelligent automobile technology, augmented reality head-up display (AR-HUD) gradually becomes the mainstream configuration of the intelligent cockpit of the automobile. Through the augmented reality head-up display, the image to be displayed can be fused with the real-time road surface, so that the driver can see the speed, navigation, signal light and other information of the automobile running while looking at the road surface, thereby not needing to look down to observe the instrument panel or the central control display screen below the steering wheel, and thus the braking reaction time in an emergency situation can be greatly improved, and the safety of driving can be improved. In related technologies, the vehicle-mounted head-up display includes an optical machine and a lens, the optical machine modulates the navigation, instrument and other information to be displayed into an imaging light beam and shoots it to the lens, and the lens projects the imaging light beam to the projection surface, so that the real-time road surface and the information to be displayed are fused. However, the existing lens has the problem of low definition. SUMMARY

[0003] Embodiments of the present application provide a lens, a projection device, a display device and a vehicle, which can improve the definition and reliability of the lens and reduce the cost of the lens.

[0004] The first aspect of the present application provides a lens, which includes a first lens arranged from an image side to an object side and a fixed lens group. The first lens is closest to the image side and has a positive focal power, and the first lens is used to move relative to the fixed lens group in the direction of the optical axis of the lens. The fixed lens group includes a first lens group, a stop and a second lens group arranged from the image side to the object side, and the first lens group is located between the first lens and the stop. The first lens group includes at least three lenses arranged from the image side to the object side, and in the direction from the image side to the object side, the first lens group has a first lens closest to the first lens with a negative focal power, a second lens with a negative focal power, and a third lens with a positive focal power. The second lens group includes at least four lenses arranged from the image side to the object side, and in the direction from the image side to the object side, the second lens group has a first lens closest to the stop with a negative focal power, a second lens with a positive focal power, a third lens with a positive focal power and a fourth lens with a positive focal power.

[0005] By moving the first lens independently during focusing, the weight is low during assembly, the amount of glue used during curing is reduced, which is conducive to reducing the cost of the lens. In addition, the architecture design of the lens can be simplified, for example, without the need to match a flange structure, which can reduce the cost of the lens. In addition, the tolerance transmission chain can be reduced, and the precision can be improved.

[0006] The optical power structure of the four lenses closest to the image side in the lens is positive-negative-negative-positive, and the optical power structure of the four lenses closest to the diaphragm in the second lens group is negative-positive-positive-positive, so that the imaging capability of the lens can be improved, and the lens can have the characteristics of high definition and high resolution to meet the projection requirements. In addition, by controlling the movement of the first lens relative to the fixed lens group, the lens focusing can be realized, so that the imaging surface is clear. Therefore, by controlling the independent movement of the first lens during focusing, not only the definition can be realized, but also the reliability of the lens can be improved.

[0007] In a possible implementation, the lens satisfies the relationship: 12.5mm≤EFL≤14.5mm, where EFL is the focal length of the lens.

[0008] When the focal length of the lens is between 12.5mm and 14.5mm, the imaging capability of the lens can be further improved, and the definition of the lens can be further improved.

[0009] In a possible implementation, the lens satisfies the relationship: 100mm≤L≤150mm, where L refers to the distance between the first lens and the image in the direction from the image side to the object side.

[0010] When the distance between the first lens and the image is between 100mm and 150mm, the definition can be further improved to meet the requirements of the lens with high definition.

[0011] In a possible implementation, the lens satisfies the relationship: -0.5≤R1 / EFL≤2, where R1 is the radius of curvature of the image side surface of the first lens, and EFL is the focal length of the lens.

[0012] When the ratio of the radius of curvature of the image side surface of the first lens to the focal length of the lens is between 0.5 and 2, the image side surface of the first lens can be prevented from being too flat, which is beneficial for aberration correction. In addition, the image side surface of the first lens can also be prevented from being too protruding, which is beneficial for packaging, transportation or assembly.

[0013] In a possible implementation, the lens satisfies the relationship: 20.1mm≤R1≤400mm, where R1 is the radius of curvature of the image side surface of the first lens.

[0014] When the radius of curvature of the image side surface of the first lens is between 20.1mm and 400mm, the image side surface of the first lens can be prevented from being too flat, which is beneficial for aberration correction. In addition, the image side surface of the first lens can also be prevented from being too protruding, which is beneficial for packaging, transportation or assembly.

[0015] In a possible implementation, the lens satisfies the relationship: -20≤R2 / EFL≤-2, where R2 is the radius of curvature of the object side surface of the lens closest to the object side, and EFL is the focal length of the lens.

[0016] When the ratio of the radius of curvature of the object side surface of the lens closest to the object side in the lens to the focal length of the lens is between -20 and -2, the object side surface of the lens closest to the object side can be prevented from being too flat, which is beneficial for aberration correction. In addition, the object side surface of the lens closest to the object side can also be prevented from being too protruding, which is beneficial for packaging, transportation or assembly.

[0017] In a possible implementation, the lens satisfies the relationship: -500mm≤R2≤-500mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side.

[0018] When the radius of curvature of the object side surface of the lens closest to the object side is between -500mm and -500mm, the object side surface of the lens closest to the object side can be prevented from being too flat, which is beneficial for aberration correction. In addition, the object side surface of the lens closest to the object side can also be prevented from being too protruding, which is beneficial for packaging, transportation or assembly.

[0019] In a possible implementation, the lens satisfies the relationship: 28mm≤BFL≤33mm, where BFL is the back focal length of the lens.

[0020] When the back focal length of the lens is between 28mm and 33mm, the optical path of the lens can be prevented from being too long or too short, which can improve the application range of the lens. If the optical path of the lens is too long, it is not conducive to design. If the optical path of the lens is too short, it is not conducive to the setting of the rear optical path.

[0021] In a possible implementation, the first lens group includes, arranged from the image side to the object side, a second lens with negative refractive power, a third lens with negative refractive power and a fourth lens with positive refractive power, the second lens is closest to the first lens, and the fourth lens is closest to the diaphragm. The second lens group includes, arranged from the image side to the object side, a fifth lens with negative refractive power, a sixth lens with positive refractive power, a seventh lens with positive refractive power and an eighth lens with positive refractive power, the fifth lens is closest to the diaphragm, and the eighth lens is closest to the object side.

[0022] The first lens group is composed of three lenses, the second lens group is composed of four lenses, and the first lens is combined, so that the lens is composed of eight lenses. This not only can improve the imaging capability of the lens to meet the needs of high definition and high reliability, but also can reduce the number of lenses and reduce the cost of the lens, which is beneficial for economic production.

[0023] In a possible implementation, the lens further includes a movable lens barrel and a fixed lens barrel, the movable lens barrel is configured to move relative to the fixed lens barrel along the optical axis of the lens, the first lens is mounted on the movable lens barrel, and the fixed lens group is mounted on the fixed lens barrel.

[0024] In this way, by controlling the movement of the movable lens barrel relative to the fixed lens barrel, the focusing of the lens can be achieved, so that the imaging surface is clear. In addition, the architecture of the lens can be simplified, which helps to reduce the cost of the lens.

[0025] The second aspect of the present application provides a projection device, comprising a display unit and the lens of any one of the first aspect. The lens comprises a first lens and a fixed lens group, and the fixed lens group is located between the first lens and the display unit. The second lens group of the lens is close to the display unit. The display unit is configured to emit image light to the lens.

[0026] The third aspect of the present application provides a display device, comprising an imaging module and the projection device of the second aspect. The imaging module is configured to generate a target image based on the image light emitted by the projection device.

[0027] The fourth aspect of the present application provides a vehicle, comprising the display device of the third aspect.

[0028] In a possible implementation, the display device is installed in the dashboard of the vehicle.

[0029] In a possible implementation, the vehicle further comprises a windshield, and the image light emitted by the display device is reflected to the human eye by the windshield. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A structural schematic diagram of a vehicle provided by an embodiment of the present application;

[0031] Figure 2 A structural schematic diagram of a display device usage scenario provided by an embodiment of the present application;

[0032] Figure 3 A structural schematic diagram of a display device installed on a vehicle provided by an embodiment of the present application;

[0033] Figure 4 A structural schematic diagram of a lens provided by an embodiment of the present application;

[0034] Figure 5 A structural schematic diagram of a projection device provided by an embodiment of the present application;

[0035] Figure 6 A Figure 5 A spherical aberration diagram of the lens in FIG. 8;

[0036] Figure 7 A Figure 5 A field curvature diagram of the lens in FIG. 8;

[0037] Figure 8 A Figure 5 A distortion diagram of the lens in FIG. 8.

[0038] Reference Signs List:

[0039] 100, lens;

[0040] 10, first lens;

[0041] 20, fixed lens group;

[0042] 30, first lens group; 31, second lens; 32, third lens; 33, fourth lens;

[0043] 40, diaphragm;

[0044] 50, second lens group; 51, fifth lens; 52, sixth lens; 55, seventh lens; 54, eighth lens;

[0045] 200, modulation unit;

[0046] 300, cover glass;

[0047] 400, projection device;

[0048] 500, display device;

[0049] 600, imaging module;

[0050] 700, display unit; 710, light source;

[0051] 800, vehicle; 810, windshield; 820, vehicle body;

[0052] X, optical axis direction. DETAILED DESCRIPTION

[0053] The terms used in the embodiment part of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application.

[0054] For ease of understanding, first, the related technical terms involved in the embodiments of the present application are explained and described.

[0055] Focal length, also known as focal length, is a way to measure the convergence or divergence of light in an optical system, which refers to the vertical distance from the optical center of the lens or lens group to the focal plane when the infinite scene passes through the lens or lens group to form a clear image on the focal plane.

[0056] Image side, with the lens as the boundary, the side where the image is located is the image side, and the side of the lens facing the image side is the image side of the lens.

[0057] Object side, the side where the modulation unit is located is the object side, and the side of the lens facing the object side is the object side.

[0058] Back focal length (BFL), defined as the distance from the lens closest to the imaging surface to the modulating unit.

[0059] Optical power, representing the refractive ability of a lens to a parallel incident light beam.

[0060] Positive optical power, indicating that the lens has a positive focal length and has a converging effect on light rays.

[0061] Negative optical power, indicating that the lens has a negative focal length and has a diverging effect on light rays.

[0062] Aperture, a device used to control the amount of light that enters the interior of an electronic device through the lens, usually inside the lens, and the size of the aperture is expressed by the F# (F-number) value.

[0063] F# (F-number), a relative value (the reciprocal of the relative aperture) derived from the focal length of the lens / the diameter of the lens, the smaller the F# value, the more light enters in the same unit of time.

[0064] Cover glass (CG), used to protect the modulating unit.

[0065] Modulating unit, used to modulate the light beam emitted by the light source to generate image light directed to the lens.

[0066] Projection chip, used to modulate the light beam emitted by the light source to generate image light directed to the lens.

[0067] Digital micromirror device (DMD), used to reflect light to form an image.

[0068] Liquid crystal on silicon (LCOS), used to reflect light to form an image.

[0069] Micro-electro-mechanical system (MEMS), which can reflect light to form an image.

[0070] Axial chromatic aberration, also known as longitudinal chromatic aberration or positional chromatic aberration, a bundle of parallel light rays along the optical axis will converge at different positions after passing through the lens, this aberration is called positional chromatic aberration or axial chromatic aberration. This is because the lens images different wavelengths of light at different positions, so that the images of different colors of light on the imaging plane cannot completely coincide, and the dispersion of complex color light is formed.

[0071] Distortion, also known as distortion, is the degree of distortion of the image of an object formed by an optical system relative to the object itself. Distortion is due to the influence of the diaphragm aberration, the intersection height of the chief ray of different fields after passing through the optical system is not equal to the ideal image height, and the difference between the two is the distortion. Therefore, distortion only changes the imaging position of the off-axis object point on the ideal plane, which causes the shape of the image to be distorted, but does not affect the sharpness of the image.

[0072] In recent years, an augmented reality (AR) head-up display (AR-HUD) is proposed, which can fuse the AR effect projected and displayed by the HUD with the real road information, enhance the driver's acquisition of the road information, and realize AR navigation, AR early warning and other functions. In the related art, the augmented display head-up display includes an optical machine and a lens, the optical machine is used to modulate the navigation, instrument and other information to be displayed into an imaging light beam and shoot to the lens, and the lens projects the imaging light beam to the projection surface to form an image, so that the real-time road and the information to be displayed are fused.

[0073] However, the existing lens has the problems of low sharpness and low reliability, resulting in poor imaging quality and being unable to meet the projection requirements of high definition and high reliability. In addition, in the focusing (adjusting the clarity of the imaging plane) process of the lens, the entire lens needs to be moved, which is heavy during assembly, and a large amount of glue needs to be used during curing, which increases the cost of the lens and is not conducive to economic production. At the same time, in order to focus, a flange structure is needed, which is not conducive to simplifying the architecture design. In addition, the tolerance transfer chain in the lens is long, the precision is poor, and the cost is high.

[0074] Therefore, the embodiments of the present application provide a lens 100, a projection device 400, a display device 500 and a vehicle 800, the lens 100 has strong imaging capability, which can improve the sharpness of the image to meet the projection requirements of high definition. In addition, the lens 100 has high reliability, which can meet the projection requirements of high reliability. In addition, the first lens closest to the image side is moved to achieve focusing, which can reduce the weight during assembly, reduce the amount of glue used during curing, and reduce the cost of the lens 100. At the same time, the architecture of the lens 100 can be simplified to reduce the cost. Finally, the tolerance transfer chain can be reduced to improve the precision.

[0075] The vehicle 800 can include, but is not limited to, a car, a truck, a motorcycle, a bus, a ship, an airplane, a helicopter, a lawn mower, an entertainment vehicle, an amusement park vehicle, a construction device, a trolley, a golf cart, a train or a trolley, etc. For example, as shown in the figure, the car is taken as the vehicle 800 in the following description. Figure 1 As shown, the vehicle 800 can include a vehicle body 820, a windshield 810 and other components. Among them, Figure 1A structural schematic diagram of a display device provided in an embodiment of the present application.

[0076] An embodiment of the present application further provides a display device 500, which can be a display, a television or a head-up display, etc. Exemplarily, a head-up display installed on a vehicle 800 is taken as an example of the display device 500, as shown in Figure 2 Figure 2 A structural schematic diagram of a display device usage scenario provided in an embodiment of the present application.

[0077] The head-up display (HUD) can project navigation information, instrument information, etc. in the driver's field of view, avoiding the driver's looking down to check the information, thereby affecting the driving safety. The image projected by the HUD is reflected by the windshield 810 (windshield glass) to form virtual images outside the vehicle 800, which can be superimposed on the real environment outside the vehicle 800, so that the driver can obtain the visual effect of augmented reality (AR), thereby realizing the functions of AR navigation, adaptive cruise, lane departure warning, etc. The types of the HUD include, but are not limited to, windshield 810 (W)-HUD, augmented reality head-up display (AR-HUD), etc.

[0078] Figure 3 A structural schematic diagram of a display device installed on a vehicle provided in an embodiment of the present application.

[0079] Referring to Figure 3 , the display device 500 can be installed in the instrument panel of the vehicle 800 to realize hidden installation. In addition, the image light (as shown by the solid arrows in Figure 3 ) emitted by the display device 500 can be incident to the windshield 810, and the windshield 810 can reflect the image light to the human eye, so that the human eye can see the virtual images located outside the windshield 810.

[0080] Continuing to refer to Figure 3 , the display device 500 can include a projection device 400 and an imaging module 600. The imaging module 600 can generate a target image based on the image light emitted by the projection device 400.

[0081] The imaging module 600 can reflect the image light emitted by the projection device 400 to the windshield 810, and the windshield 810 can reflect the image light to the human eye to form the target image.

[0082] The specific structure of the imaging module 600 is not limited here. Exemplarily, as shown in Figure 3 ​As shown, the imaging module 600 can include a curved mirror for reflecting the image light emitted by the projection device 400 to the windshield 810, which can reflect the image light to the human eye. In addition, since the concave surface of the curved mirror can reflect the imaging light, the image generated by the projection device 400 can be magnified by the curved mirror, and the user can see the magnified virtual image.

[0083] Referring to Figure 3 As shown, the projection device 400 can include a display unit 700 and a lens 100, the display unit 700 is configured to emit image light to the lens 100, and the lens 100 is configured to transmit the image light to the imaging module 600.

[0084] The display unit 700 can include a light source 710 and a modulation unit 200, the light source 710 is configured to generate a light beam carrying image data. The modulation unit 200 is configured to modulate the light beam generated by the light source 710 according to the image data, and generate image light directed to the lens 100.

[0085] The specific structure of the modulation unit 200 is not limited here. Exemplarily, the modulation unit 200 can be a projection chip. The projection chip can be a reflective spatial light modulator and have a function of changing the polarization direction of the incident linearly polarized light, for example, an LCoS. Alternatively, the projection chip can also be a reflective spatial light modulator and not have a function of changing the polarization direction of the incident linearly polarized light, for example, a MEMS or a DMD. Alternatively, the projection chip can also be a transmissive spatial light modulator, for example, an LCD, etc.

[0086] In some possible implementation manners, the projection device 400 can further include a cover glass 300, which is disposed between the lens 100 and the modulation unit 200 in the direction from the image side to the object side, and the cover glass 300 can protect the modulation unit 200.

[0087] The number of cover glasses 300 can be one or more, which is not limited here. In addition, when the number of cover glasses 300 is more than one, all the cover glasses 300 are disposed between the modulation unit 200 and the lens 100.

[0088] The lens 100 provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0089] Figure 4 A structural schematic diagram of a lens provided by the embodiments of the present application.

[0090] Referring to Figure 4As shown, the lens 100 comprises a first lens 10 and a fixed lens group 20 arranged from the image side to the object side. The first lens 10 is closest to the image side and has a positive focal power, and the first lens 10 is configured to move relative to the fixed lens group 20 along the optical axis direction X of the lens 100. The fixed lens group 20 comprises a first lens group 30, a diaphragm 40 and a second lens group 50 arranged from the image side to the object side, and the first lens group 30 is closest to the first lens 10 and is located between the first lens 10 and the diaphragm 40.

[0091] Since the first lens 10 can move relative to the fixed lens group 20 along the optical axis direction X, the focusing can be achieved by moving the first lens 10, and the imaging surface is clear. Therefore, by moving the first lens independently during focusing, the weight during assembly is low, the amount of glue used during curing is reduced, and the cost of the lens 100 is reduced. In addition, the architecture design of the lens 100 can be simplified, for example, without the need for a flange structure, which can reduce the cost of the lens 100. In addition, the tolerance transmission chain can be reduced, and the precision can be improved.

[0092] The first lens group 30 comprises at least three lenses arranged from the image side to the object side, for example Figure 4 As shown, the first lens group 30 comprises three lenses, i.e. a second lens 31, a third lens 32 and a fourth lens 33, and the number of lenses constituting the first lens group 30 can also be more than three. In the first lens group 30, the first lens closest to the first lens 10 has a negative focal power, the second lens has a negative focal power, and the third lens has a positive focal power along the direction from the image side to the object side, for example Figure 4 As shown, the second lens 31 is closest to the first lens 10, the second lens 31 has a negative focal power, the third lens 32 has a negative focal power, and the fourth lens 33 has a positive focal power, and the fourth lens 33 is closest to the diaphragm 40.

[0093] The second lens group 50 comprises at least four lenses arranged from the image side to the object side, for example Figure 4 As shown, the second lens group 50 comprises four lenses, i.e. a fifth lens 51, a sixth lens 52, a seventh lens 55 and an eighth lens 54, and the number of lenses constituting the second lens group 50 can also be more than four. In the second lens group 50, the first lens closest to the diaphragm 40 has a negative focal power, the second lens has a positive focal power, the third lens has a positive focal power, and the fourth lens has a positive focal power along the direction from the image side to the object side, for example Figure 4 As shown, the fifth lens 51 is closest to the diaphragm 40, the fifth lens 51 has a negative focal power, the sixth lens 52 has a positive focal power, the seventh lens 55 has a positive focal power, the eighth lens 54 has a positive focal power, and the eighth lens 54 is closest to the object side.

[0094] In summary, the optical power architecture of the four lenses closest to the image side in the lens 100 is positive-negative-negative-positive, and the optical power architecture of the four lenses closest to the diaphragm 40 in the second lens group 50 is negative-positive-positive-positive, so that the imaging capability of the lens 100 can be improved, and the lens 100 can have the characteristics of high definition and high resolution to meet the projection requirements. In addition, by controlling the movement of the first lens 10 relative to the fixed lens group 20, the lens 100 can be focused to make the imaging surface clear. Therefore, by controlling the independent movement of the first lens 10 during focusing, not only the definition can be achieved, but also the reliability of the lens 100 can be improved.

[0095] In addition, as shown in Figure 4 , the first lens group 30 is composed of three lenses, the second lens group 50 is composed of four lenses, and in combination with the first lens 10, the lens 100 is composed of eight lenses. This not only improves the imaging capability of the lens 100 to meet the requirements of high definition and high reliability, but also reduces the number of lenses and the cost of the lens 100, which is conducive to economic production.

[0096] As shown in Figure 4 , the first lens group 30 includes three lenses, and the three lenses are located between the first lens 10 and the diaphragm 40. Therefore, when the number of lenses in the first lens group 30 exceeds three, all the lenses in the first lens group 30 are arranged between the first lens 10 and the diaphragm 40. Similarly, when the number of lenses in the second lens 31 is four or more, all the lenses in the second lens group 50 are arranged between the diaphragm 40 and the object side.

[0097] In some possible implementations, the lens 100 can also satisfy the relationship: 12.5mm≤EFL≤14.5mm, where EFL is the focal length of the lens 100.

[0098] Correspondingly, when the focal length of the lens 100 is between 12.5mm and 14.5mm, the imaging capability of the lens 100 can be further improved, and the definition of the lens 100 can be further improved.

[0099] The specific value of the focal length of the lens 100 is not limited here. The focal length of the lens 100 can be 12.5mm, 12.8mm, 13mm, 13.5mm, 13.6mm, 13.99mm, 14.0mm, 14.1mm, 14.2mm, 14.3mm, 14.4mm or 14.5mm, etc.

[0100] In some possible implementations, the lens 100 can also satisfy the relationship: 100mm≤L≤150mm, where L refers to the distance between the first lens 10 and the image (projection surface) in the direction from the image side to the object side (as shown by L in Figure 4 ).

[0101] Correspondingly, when the distance between the first lens 10 and the image is between 100mm and 150mm, the definition can be further improved to meet the requirements of the high-definition lens 100.

[0102] The specific value of L is not limited herein. L can be 105mm, 110mm, 111mm, 112mm, 115mm, 120mm, 121mm, 125mm, 128mm, 130mm, 131.5mm, 135mm, 139mm, 140mm, 143mm, 145.5mm, 148mm or 150mm, etc.

[0103] In some possible implementation manners, the lens 100 can also satisfy the relationship: -0.5≤R1 / EFL≤2, R1 is the radius of curvature of the image side of the first lens 10, and EFL refers to the focal length of the lens 100.

[0104] Correspondingly, when the ratio of the radius of curvature of the image side of the first lens 10 to the focal length of the lens 100 is between -0.5 and 2, the image side of the first lens 10 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the image side of the first lens 10 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0105] The specific ratio of R1 / EFL is not limited herein. The ratio of R1 / EFL can be -0.5, -0.45, -0.4187, -0.4, -0.35, -0.3, -0.1, 1, 1.1, 1.5, 1.689 or 2, etc.

[0106] In some possible implementation manners, the lens 100 can also satisfy the relationship: 20.1mm≤R1≤400mm, R1 is the radius of curvature of the image side of the lens 100 closest to the image side.

[0107] Correspondingly, when the radius of curvature of the image side of the first lens 10 is between 20.1mm and 400mm, the image side of the first lens 10 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the image side of the first lens 10 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0108] The specific value of R1 is not limited herein. The value of R1 can be 20.1mm, 20.5mm, 21mm, 21.6mm, 22mm, 22.8mm, 23mm, 23.5mm, 24mm, 25mm, 26mm, 30mm, 35mm, 40mm, 45mm, 50mm,

[0109] 55mm, 60mm, 61.698mm, 65mm, 66mm, 69mm, 70mm, 100mm, 150mm, 200mm, 250mm,

[0110] 300mm, 350mm, 400mm, etc.

[0111] In some possible implementation manners, the lens 100 can also satisfy a relationship: -20≤R2 / EFL≤-2, R2 is the curvature radius of the object side surface of the closest object side lens in the lens 100, and EFL is the focal length of the lens 100.

[0112] Correspondingly, when the ratio of the curvature radius of the object side surface of the closest object side lens in the lens 100 to the focal length of the lens 100 is located in -20 to -2, the object side surface of the closest object side lens in the lens 100 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the object side surface of the closest object side lens in the lens 100 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0113] The specific ratio of R2 / EFL is not limited here. The ratio of R2 / EFL can be -20, -15, -10, -9.5, -9, -8, -8.5, -8, -7.5, -7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5, -3, -2.5, -2, etc.

[0114] In some possible implementation manners, the lens 100 can also satisfy a relationship: -500mm≤R2≤500mm, R2 is the curvature radius of the object side surface of the closest object side lens in the lens 100.

[0115] Correspondingly, when the curvature radius of the object side surface of the closest object side lens in the lens 100 is located in -500mm to 500mm, the object side surface of the closest object side lens in the lens 100 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the object side surface of the closest object side lens in the lens 100 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0116] The specific value of R2 is not limited here. The value of R2 can be -500 mm, -450 mm, -300 mm, -180 mm, -150 mm, -140 mm, -135 mm, -130 mm, -125 mm, -120 mm, -115 mm, -110 mm, -105 mm, -100 mm, -95 mm, -90 mm, -85 mm, -80 mm, -75 mm, -70 mm, -65 mm, -60 mm, -55 mm, -50 mm, 50 mm, 100 mm, 150 mm, 250 mm, 350 mm, 400 mm, 450 mm, 500 mm, etc.

[0117] In some possible implementation manners, the lens 100 can also satisfy the relationship: 28 mm≤BFL≤33 mm, where BFL is the back focal length of the lens 100.

[0118] Correspondingly, when the back focal length of the lens 100 is between 28 mm and 33 mm, the optical path of the lens 100 can be avoided to be too long or too short, and the application range of the lens 100 can be improved. Wherein, the optical path of the lens 100 is too long, which is not conducive to design. The optical path of the lens 100 is too short, which is not conducive to the setting of the rear optical path.

[0119] The specific value of the back focal length of the lens 100 is not limited here. The focal length of the lens 100 can be 28 mm, 28.6 mm, 29 mm, 29.5 mm, 29.887 mm, 30 mm, 30.5 mm, 31 mm, 31.5 mm, 32 mm, 32.5 mm or 33 mm, etc.

[0120] In some possible implementation manners, the lens 100 can also include a movable barrel (not shown in the figure) and a fixed barrel (not shown in the figure), the movable barrel is used to move relative to the fixed barrel along the optical axis direction X of the lens 100, the first lens 10 is mounted on the movable barrel, and the fixed lens group 20 is mounted on the fixed barrel.

[0121] In this way, by controlling the movement of the movable barrel relative to the fixed barrel, the focusing of the lens 100 can be realized, so that the imaging surface is clear. In addition, the architecture of the lens 100 can be simplified, which helps to reduce the cost of the lens 100.

[0122] In some embodiments, the movable barrel can be movably connected to the fixed barrel, and the movable barrel is supported by the fixed barrel, which helps to reduce the number of parts of the lens 100. Of course, in other embodiments, the movable barrel can also be not connected with the fixed barrel.

[0123] The lens 100 and the projection device 400 will be described in detail below in combination with specific embodiments.

[0124] Figure 5 FIG. 1 shows a schematic structural diagram of a projection device according to an embodiment of the present application.

[0125] Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two. Figure 5 Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two.

[0126] Figure 5 Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two.

[0127] Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two. Figure 5 Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two.

[0128] Figure 5 Referring to FIG. 1, the projection device 400 according to the embodiment of the present application can include a modulation unit 200, a cover glass 300, and a lens 100. The cover glass 300 is disposed between the modulation unit 200 and the lens 100 along an optical axis direction X of the lens 100. The number of the cover glass 300 can be two, and the two cover glasses 300 are arranged side by side along the optical axis direction X of the lens 100. It should be noted that the number of the cover glass 300 can be less than or more than two.

[0129] ​​The first lens 10 has positive refractive power, and the focal length f1 of the first lens 10 is 30.471. The second lens 31 has negative refractive power, and the focal length f2 of the second lens 31 is -18.962. The third lens 32 has negative refractive power, and the focal length f3 of the third lens 32 is -29.934. The fourth lens 33 has positive refractive power, and the focal length f4 of the fourth lens 33 is 55.229. The fifth lens 51 has negative refractive power, and the sixth lens 52 has positive refractive power. The fifth lens 51 and the sixth lens 52 constitute a cemented lens, and the cemented lens has negative refractive power. The focal length f56 of the cemented lens is -112.950. The seventh lens 55 has positive refractive power, and the focal length f7 of the seventh lens 55 is 65.373. The eighth lens 54 has positive refractive power, and the focal length f8 of the eighth lens 54 is 36.17.

[0130] The radius of curvature R1 of the image side surface of the first lens 10 is 23.68 mm, which is greater than 20.1 mm and less than 400 mm, and meets the requirement. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 10 to the focal length EFL of the lens 100 is 1.63, which is greater than -0.2 and less than 2, and meets the requirement.

[0131] In the direction from the image side to the object side, the distance between the object side surface of the eighth lens 54 and the modulation unit 200 is 31.85 mm, that is, the back focal length BFL of the lens 100 is 31.85 mm, which is greater than 28 mm and less than 33 mm, and meets the requirement.

[0132] The lens closest to the object side in the lens 100 is the eighth lens 54, and the radius of curvature R2 of the object side surface of the eighth lens 54 is -102.89 mm, which is greater than -500 mm and less than 500 mm, and meets the requirement. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 54 to the focal length EFL of the lens 100 is -7.096, which is greater than -20 and less than -2, and meets the requirement.

[0133] The focal length EFL of the lens 100 is 14.5 mm, which is greater than 13.5 mm and equal to 14.5 mm, and meets the requirement.

[0134] Table 1 shows the optical parameters of each optical element in the projection device 400 provided in the embodiment of the present application.

[0135]

[0136]

[0137] Wherein, R is the radius of curvature of the optical element (such as a lens or a cover plate glass 300) at the corresponding position of the optical axis, TH is the surface thickness of the optical element in the direction X along the optical axis, Nd is the refractive index of the d-line illumination to each optical element, and Vd is the Abbe number of the optical element.

[0138] Wherein, S1 is the image side surface of the first lens 10, S2 is the object side surface of the first lens 10. S3 is the image side surface of the second lens 31, S4 is the object side surface of the second lens 31. S5 is the image side surface of the third lens 32, S6 is the object side surface of the third lens 32. S7 is the image side surface of the fourth lens 33, S8 is the object side surface of the fourth lens 33. S9 is the diaphragm 40, S10 is the image side surface of the fifth lens 51, S11 is the cemented surface of the fifth lens 51 and the sixth lens 52, S12 is the object side surface of the sixth lens 52. S13 is the image side surface of the seventh lens 55, S14 is the object side surface of the seventh lens 55. S15 is the image side surface of the eighth lens 54, S16 is the object side surface of the eighth lens 54. S17 is the image side surface of the first cover glass 300 close to the lens 100, S18 is the object side surface of the first cover glass 300 close to the lens 100, S19 is the image side surface of the second cover glass 300 close to the lens 100, S20 is the object side surface of the second cover glass 300 close to the lens 100, OBJ is the projection surface (object surface), ImgH is the imaging surface.

[0139] Table 2 shows the conjugate values under different projection distance conditions of L / D.

[0140] L (mm) 110.000 130.000 140.323 150.000 D (mm) 2.830 1.613 0.880 0.278

[0141] Wherein, L refers to the distance between the first lens 10 and the projection surface (image), and D refers to the distance between the first lens 10 and the second lens 31.

[0142] From Table 2, it can be seen that by controlling the first lens 10 to move different distances along the optical axis X relative to the fixed lens group 20, the distance between the image side surface of the first lens 10 and the image (projection surface) changes. For example, when D changes from 2.830mm to 1.613mm, the corresponding L also changes from 110.000mm to 130.000mm.

[0143] Table 3 shows the optical parameters of the lens 100 in Figure 5 .

[0144] f1 (mm) 30.471 R1 / EFL 1.63 f2 (mm) -18.962 R2 / EFL -7.096 f3 (mm) -29.934 EFL1 -112.36 f4 (mm) 55.229 EFL2 26.153 f56 (mm) -112.950 EFL (mm) 14.5 f7 (mm) 65.373 BFL (mm) 31.850 f8 (mm) 36.177

[0145] Wherein, EFL is the focal length of lens 100, EFL1 is the focal length of the four lenses from the first lens 10 to the fourth lens 33, EFL2 is the focal length of the second lens group 50, BFL is the back focal length of lens 100, R1 is the radius of curvature of the image side of the first lens 10, R2 is the radius of curvature of the object side of the lens closest to the object side in lens 100, f1 is the focal length of the first lens 10, f2 is the focal length of the second lens 31, f3 is the focal length of the third lens 32, f4 is the focal length of the fourth lens 33, f56 is the focal length of the cemented lens formed by the fifth lens 51 and the sixth lens 523, f7 is the focal length of the seventh lens 55, and f8 is the focal length of the eighth lens 54.

[0146] Figure 6 for Figure 5 The spherical chromatic aberration diagram of lens 100. Figure 6 In the diagram, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberrations along the axial direction, with units of millimeters. Figure 6 In the diagram, the three curves correspond to the axial aberration curves of light with wavelengths of 625nm, 550nm, and 455nm after passing through the lens 100 in this embodiment. From... Figure 6 As can be seen, in this embodiment, axial aberration is controlled within a very small range, resulting in good correction.

[0147] Figure 7 for Figure 5 The image of the 100-shot scene in the middle is a fading curve. Figure 8 for Figure 5 The distortion image of lens 100 in the image. Figure 7 In the diagram, S represents the field curvature of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature of light with a wavelength of 550 nm in the sagittal image plane. Figure 8 In the diagram, the solid line represents the distortion value of light with a center wavelength of 550nm passing through the lens 100 in this embodiment. (Combined with...) Figure 7 and Figure 8 It can be seen that the lens 100 provided in this embodiment controls field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0148] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0149] In the embodiments of the present application or the devices or elements implied by the present application must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0150] The terms "first", "second", "third", "fourth" and the like in the description of the embodiments of the present application and the above-mentioned drawings (if any) are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the embodiments of the present application described herein can be implemented, for example, in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0151] The term "a plurality of" herein refers to two or more. The term "and / or" herein is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " herein generally represents that the associated objects before and after are in an "or" relationship; in the formula, the character " / " represents that the associated objects before and after are in a "division" relationship.

[0152] It can be understood that the various numbers involved in the embodiments of the present application are only for the convenience of differentiation in the description, and do not limit the scope of the embodiments of the present application.

[0153] It can be understood that in the embodiments of the present application, the size of the serial number of each process described above does not mean the order of execution, and the execution order of each process should be determined by its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claims

1. A lens characterized by comprising: comprises a first lens and a fixed lens group arranged from an image side to an object side; the first lens is closest to the image side and has a positive refractive power, the first lens being configured to move relative to the fixed lens group in a direction of an optical axis of the lens; the fixed lens group comprises a first lens group, a diaphragm and a second lens group arranged from the image side to the object side, the first lens group being located between the first lens and the diaphragm; the first lens group comprises at least three lenses arranged from the image side to the object side, in a direction from the image side to the object side, a first lens closest to the first lens in the first lens group has a negative refractive power, a second lens has a negative refractive power, and a third lens has a positive refractive power; the second lens group comprises at least four lenses arranged from the image side to the object side, in a direction from the image side to the object side, a first lens closest to the diaphragm in the second lens group has a negative refractive power, a second lens has a positive refractive power, a third lens has a positive refractive power, and a fourth lens has a positive refractive power.

2. The lens according to claim 1, characterized in that, the lens satisfies a relationship: 12.5mm ≤ EFL ≤ 14.5mm, the EFL being a focal length of the lens.

3. The lens according to claim 1 or 2, characterized in that, the lens satisfies a relationship: 100mm ≤ L ≤ 150mm, the L being a distance between the first lens and an image in a direction from the image side to the object side.

4. The lens according to any one of claims 1 to 3, characterized in that, the lens satisfies a relationship: -0.5 ≤ R1 / EFL ≤ 2, the R1 being a radius of curvature of an image side surface of the first lens, and the EFL being a focal length of the lens.

5. The lens according to any one of claims 1 to 4, characterized in that, the lens satisfies a relationship: 20.1mm ≤ R1 ≤ 400mm, the R1 being a radius of curvature of an image side surface of the first lens.

6. The lens according to any one of claims 1 to 5, characterized in that, the lens satisfies a relationship: -20 ≤ R2 / EFL ≤ -2, the R2 being a radius of curvature of an object side surface of the lens closest to the object side, and the EFL being a focal length of the lens.

7. The lens according to any one of claims 1 to 6, characterized in that the lens satisfies a relationship: -500mm ≤ R2 ≤ 500mm, the R2 being a radius of curvature of an object side surface of the lens closest to the object side.

8. The lens according to any one of claims 1 to 7, characterized in that the lens satisfies a relationship: 28mm ≤ BFL ≤ 33mm, the BFL being a back focal length of the lens.

9. The lens according to any one of claims 1 to 8, characterized in that, the first lens group comprises a second lens having a negative refractive power, a third lens having a negative refractive power, and a fourth lens having a positive refractive power arranged from the image side to the object side, the second lens being closest to the first lens, and the fourth lens being closest to the diaphragm; the second lens group comprises a fifth lens having a negative refractive power, a sixth lens having a positive refractive power, a seventh lens having a positive refractive power, and an eighth lens having a positive refractive power arranged from the image side to the object side, the fifth lens being closest to the diaphragm, and the eighth lens being closest to the object side.

10. The lens according to any one of claims 1 to 9, characterized in that, the lens further comprises a movable barrel and a fixed barrel, the movable barrel being configured to move relative to the fixed barrel in a direction of an optical axis of the lens, the first lens being mounted on the movable barrel, and the fixed lens group being mounted on the fixed barrel.

11. A projection apparatus, characterized by comprising: a lens as claimed in any one of claims 1 to 10, and a display unit; The lens comprises a first lens and a fixed lens group, the fixed lens group is located between the first lens and the display unit; The display unit is used for emitting image light to the lens.

12. A display device comprising: The projection device comprises an imaging module and the display device of claim 11. The imaging module generates a target image based on the image light emitted by the projection device.

13. A vehicle, characterized by The display device comprises the display device of claim 12.

14. The vehicle of claim 13, wherein, The display device is installed in an instrument panel of the vehicle.

15. Vehicle according to claim 13 or 14, characterized in that The vehicle further comprises a windshield, the image light emitted by the display device is incident to the windshield, and the windshield reflects the image light to a human eye.

Images