Lens, projection device, display device, and transportation means

Abstract

Embodiments of the present application relate to the technical field of optics, and provide a lens, a projection device, a display device, and a transportation means. The lens comprises a first lens and a fixed lens group. The first lens is closest to an image side and has positive focal power, and the first lens is used for moving relative to the fixed lens group in the optical axis direction of the lens. The fixed lens group comprises a first lens group, a stop, and a second lens group, and the first lens group is located between the first lens and the stop. In the first lens group, the lens that is closest to the first lens has negative focal power, the lens that is the second closest to the first lens has negative focal power, and the lens that is the third closest to the first lens has positive focal power. In the second lens group, the lens that is closest to the stop has negative focal power, the lens that is the second closest to the stop has positive focal power, the lens that is the third closest to the stop has positive focal power, and the lens that is the fourth closest to the stop has positive focal power. By means of the configuration, the lens has high definition and high reliability, and the cost of the lens is reduced.

Description

Lens, projection device, display device and vehicle

[0001] The present application claims priority to the Chinese patent application No. 202410538600.7, filed on April 30, 2024, and entitled "Lens, projection device, display device and vehicle", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] Embodiments of the present application relate to the field of optical technology, in particular to a lens, a projection device, a display device and a vehicle. BACKGROUND

[0003] 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, without looking down at the instrument panel or the central control display screen below the steering wheel, thereby greatly improving the braking reaction time in emergency situations and improving the safety of driving. 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

[0004] 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.

[0005] The first aspect of the present application provides a lens, comprising 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 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 comprises 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 comprises 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 closest to the first lens in the first lens group has a negative focal power, the second lens has a negative focal power, and the third lens has a positive focal power. The second lens group comprises 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 first lens closest to the stop in the second lens group 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.

[0006] By moving the first lens independently during focusing, the weight during assembly is low, the glue used during curing is reduced, which is conducive to reducing the cost of the lens. In addition, the lens architecture design can be simplified, such as not needing to match the 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.

[0007] The optical power architecture of the four lenses closest to the image side in the lens is positive-negative-negative-positive, and the optical power architecture 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, meeting 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.

[0008] In a possible implementation, the lens satisfies the relationship: 12.5mm≤EFL≤14.5mm, where EFL is the focal length of the lens.

[0009] 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.

[0010] 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.

[0011] 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 high-definition lenses.

[0012] 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.

[0013] 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 avoided to be too flat, which is conducive to aberration correction. In addition, the image side surface of the first lens can also be avoided to be too protruding, which is conducive to packaging, transportation or assembly.

[0014] 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.

[0015] When the curvature radius of the image-side surface of the first lens is located in the range of 20.1mm to 400mm, the image-side surface of the first lens can be prevented from being too flat, which is beneficial to aberration correction. In addition, the image-side surface of the first lens can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0016] In a possible implementation, the lens satisfies a relationship: -20≤R2 / EFL≤-2, R2 is the curvature radius of the object-side surface of the lens closest to the object side, and EFL is the focal length of the lens.

[0017] When the ratio of the curvature radius of the object-side surface of the lens closest to the object side to the focal length of the lens is located in the range of -20 to -2, the object-side surface of the lens closest to the object side can be prevented from being too flat, which is beneficial to 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 to packaging, transportation or assembly.

[0018] In a possible implementation, the lens satisfies a relationship: -500mm≤R2≤-500mm, R2 is the curvature radius of the object-side surface of the lens closest to the object side.

[0019] When the curvature radius of the object-side surface of the lens closest to the object side is located in the range of -500mm to -500mm, the object-side surface of the lens closest to the object side can be prevented from being too flat, which is beneficial to 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 to packaging, transportation or assembly.

[0020] In a possible implementation, the lens satisfies a relationship: 28mm≤BFL≤33mm, BFL is the back focal length of the lens.

[0021] When the back focal length of the lens is located in the range of 28mm to 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-end optical path.

[0022] 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.

[0023] The first lens group is composed of three lenses, the second lens group is composed of four lenses, and the lens is composed of eight lenses in combination with the first lens, which can not only improve the imaging capability of the lens to meet the requirements of high definition and high reliability, but also reduce the number of lenses and the cost of the lens, which is conducive to economic production.

[0024] 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.

[0025] In this way, the focusing of the lens can be realized by controlling the movement of the movable lens barrel relative to the fixed lens barrel, 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.

[0026] The second aspect of the present application provides a projection device, which includes a display unit and the lens of any one of the first aspect. The lens includes 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.

[0027] The third aspect of the present application provides a display device, which includes 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.

[0028] The fourth aspect of the present application provides a vehicle, which includes the display device of the third aspect.

[0029] In a possible implementation, the display device is installed in the dashboard of the vehicle.

[0030] In a possible implementation, the vehicle further includes a windshield, and the image light emitted by the display device is reflected to the human eye by the windshield. BRIEF DESCRIPTION OF DRAWINGS

[0031] FIG. 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application;

[0032] FIG. 2 is a structural schematic diagram of a display device according to an embodiment of the present application in a use scenario;

[0033] FIG. 3 is a structural schematic diagram of a display device according to an embodiment of the present application installed on a vehicle;

[0034] FIG. 4 is a structural schematic diagram of a lens according to an embodiment of the present application;

[0035] FIG. 5 is a structural schematic diagram of a projection device according to an embodiment of the present application;

[0036] Figure 6 is a spherochromatic chart of the lens in Figure 5;

[0037] Figure 7 is a field curvature chart of the lens in Figure 5;

[0038] Figure 8 is a distortion chart of the lens in Figure 5.

[0039] Legend: 100, lens; 10, first lens; 20, fixed lens group; 30, first lens group; 31, second lens; 32, third lens; 33, fourth lens; 40, diaphragm; 50, second lens group; 51, fifth lens; 52, sixth lens; 55, seventh lens; 54, eighth lens; 200, modulation unit; 300, cover glass; 400, projection device; 500, display device; 600, imaging module; 700, display unit; 710, light source; 800, vehicle; 810, windshield; 820, vehicle body; X, optical axis direction. DETAILED DESCRIPTION

[0040] 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.

[0041] For ease of understanding, first, the related technical terms involved in the embodiments of the present application are explained and described.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Back focal length (BFL for short), defined as the distance from the lens closest to the imaging surface to the modulation unit in the lens.

[0046] Optical power, which represents the refractive ability of the lens to incident parallel light beams.

[0047] Positive optical power, indicating that the lens has a positive focal length and has a converging effect on light rays.

[0048] Negative optical power, indicating that the lens has a negative focal length and has a diverging effect on light rays.

[0049] Aperture, is used to control the amount of light through the lens into the electronic device inside the device, usually in the lens, the size of the aperture is expressed by F# (F-number) value.

[0050] F# aperture number, is the focal length of the lens / lens diameter derived from the relative value (relative aperture of the inverse), the smaller the F# aperture number value, in the same unit of time, the more light.

[0051] Cover glass (CG), used to protect the modulation unit.

[0052] Modulation unit, for modulating the light beam emitted by the light source to generate image light to the lens.

[0053] Projection chip, for modulating the light beam emitted by the light source to generate image light to the lens.

[0054] Digital micromirror devices (DMD), for reflecting light to form an image.

[0055] Liquid crystal on silicon (LCOS), for reflecting light to form an image.

[0056] Micro-electro-mechanical system (MEMS), can reflect light to form an image.

[0057] Axial chromatic aberration, also known as longitudinal chromatic aberration or position chromatic aberration, a bundle of parallel to the optical axis of light, after the lens will converge in different positions, this aberration is called position chromatic aberration or axial chromatic aberration. This is due to the different positions of the lens for each wavelength of light, so that the final imaging of different colors of light can not be completely coincident, and the dispersion of the complex color light.

[0058] Distortion, also known as distortion, the degree of distortion of the image formed by the optical system relative to the object itself. Distortion is due to the influence of diaphragm aberration, the chief ray of different field of view through the optical system after the intersection height of Gaussian image plane is not equal to the ideal image height, 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, so that the shape of the image is distorted, but does not affect the clarity of the image.

[0059] An augmented reality (AR) head-up display (AR-HUD) proposed in recent years can fuse the AR effect projected and displayed by the HUD with real road information, enhance the acquisition of road information by the driver, and realize AR navigation, AR early warning and other functions. In related technologies, the augmented display head-up display includes an optical engine and a lens. The optical engine is configured to modulate navigation, instrument and other information to be displayed into an imaging light beam and project the imaging light beam to the lens. The lens projects the imaging light beam to a projection surface to form an image, so that the real-time road and the information to be displayed are fused.

[0060] However, the existing lens has low definition 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 surface) process of the lens, the entire lens needs to be moved, which is heavy during assembly and requires a large amount of glue during curing, thereby increasing the cost of the lens and being 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.

[0061] 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, can improve the definition of the image, and meet the projection requirements of high definition. In addition, the lens 100 has high reliability, can meet the projection requirements of high reliability. In addition, the first lens closest to the image side is moved to realize 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.

[0062] 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 lawnmower, 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, as shown in FIG. 1, the vehicle 800 can include a vehicle body 820, a windshield 810 and other components. FIG. 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application.

[0063] The embodiments of the present application also provide a display device 500, which can be a display, a television or a head-up display, etc. For example, as shown in the figure, the head-up display installed on the vehicle 800 is taken as the display device 500 in the following description, as shown in FIG. 2. FIG. 2 is a structural schematic diagram of a display device usage scenario according to an embodiment of the present application.

[0064] The head-up display (HUD) can project navigation information, instrument information, etc. in the driver's field of view, avoiding the driver looking down to check the information, thereby affecting the driving safety. The image projected by the HUD is reflected by the windshield 810 (windshield), and a virtual image is formed outside the vehicle 800. The virtual image 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.

[0065] FIG. 3 is a structural schematic diagram of a display device provided by an embodiment of the present application installed on a vehicle.

[0066] Referring to FIG. 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 emitted by the display device 500 (as shown by the solid arrows in FIG. 3) 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 image located outside the windshield 810.

[0067] Continuing to refer to FIG. 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.

[0068] 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.

[0069] The specific structure of the imaging module 600 is not limited here. Exemplarily, as shown in FIG. 3, the imaging module 600 can include a curved mirror, which is used to 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. 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.

[0070] Referring to FIG. 3, the projection device 400 can include a display unit 700 and a lens 100, the display unit 700 is used to emit image light to the lens 100, and the lens 100 transmits the image light to the imaging module 600.

[0071] 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.

[0072] 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.

[0073] In some possible implementation manners, the projection device 400 can further include a cover glass 300. The cover glass 300 is arranged 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.

[0074] The number of the cover glass 300 can be one or more, which is not limited here. In addition, when the number of the cover glass 300 is more than one, all the cover glasses 300 are arranged between the modulation unit 200 and the lens 100.

[0075] The lens 100 provided by the embodiments of the present application is described in detail below with reference to the accompanying drawings.

[0076] FIG. 4 is a structural schematic diagram of a lens provided by an embodiment of the present application.

[0077] Referring to FIG. 4, the lens 100 includes 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. 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 includes a first lens group 30, a diaphragm 40 and a second lens group 50 arranged from the image side to the object side. The first lens group 30 is closest to the first lens 10, and the first lens group 30 is located between the first lens 10 and the diaphragm 40.

[0078] 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 then 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, which is beneficial to reduce the cost of the lens 100. In addition, the architecture design of the lens 100 can be simplified, for example, without the need to match the 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.

[0079] The first lens group 30 includes at least three lenses arranged from the image side to the object side, for example, as shown in FIG. 4, the first lens group 30 includes three lenses, which are the second lens 31, the third lens 32 and the fourth lens 33 respectively. Of course, the number of lenses constituting the first lens group 30 can also be more than three. In the direction from the image side to the object side, the first lens closest to the first lens 10 in the first lens group 30 has a negative focal power, the second lens has a negative focal power, and the third lens has a positive focal power. For example, as shown in FIG. 4, 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. The fourth lens 33 is closest to the diaphragm 40.

[0080] The second lens group 50 includes at least four lenses arranged from the image side to the object side, for example, as shown in FIG. 4, the second lens group 50 includes four lenses, which are the fifth lens 51, the sixth lens 52, the seventh lens 55 and the eighth lens 54 respectively. Of course, the number of lenses constituting the second lens group 50 can also be more than four. In the direction from the image side to the object side, the first lens closest to the diaphragm 40 in the second lens group 50 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. For example, as shown in FIG. 4, 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, and the eighth lens 54 has a positive focal power. The eighth lens 54 is closest to the object side.

[0081] In summary, the focal power architecture of the four lenses closest to the image side in the lens 100 is positive-negative-negative-positive, and the focal 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 then the lens 100 can have the characteristics of high definition and high resolution, and meet the projection requirements. In addition, by controlling the movement of the first lens 10 relative to the fixed lens group 20, the focusing of the lens 100 can be achieved, so that the imaging surface is 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.

[0082] In addition, as shown in FIG. 4, the first lens group 30 is composed of three lenses, and the second lens group 50 is composed of four lenses, in combination with the first lens 10, so that the lens 100 is composed of eight lenses, which not only can improve the imaging capability of the lens 100 to meet the requirements of high definition and high reliability, but also can reduce the number of lenses and reduce the cost of the lens 100, which is conducive to economic production.

[0083] As shown in FIG. 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 than four, all the lenses in the second lens group 50 are arranged between the diaphragm 40 and the object side.

[0084] In some possible implementation manners, the lens 100 can also satisfy the relationship: 12.5mm≤EFL≤14.5mm, where EFL is the focal length of the lens 100.

[0085] 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.

[0086] The specific value of the focal length of the lens 100 is not limited herein. 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, and the like.

[0087] In some possible implementation manners, 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 FIG. 4).

[0088] 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 lens 100 with high definition.

[0089] 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, and the like.

[0090] In some possible implementation manners, the lens 100 can also satisfy a relationship: -0.5≤R1 / EFL≤2, R1 is the curvature radius of the image side surface of the first lens 10, and EFL refers to the focal length of the lens 100.

[0091] Correspondingly, when the ratio of the curvature radius of the image side surface of the first lens 10 to the focal length of the lens 100 is located in the range of -0.5 to 2, the image side surface of the first lens 10 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the image side surface of the first lens 10 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0092] 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, and the like.

[0093] In some possible implementation manners, the lens 100 can also satisfy a relationship: 20.1mm≤R1≤400mm, R1 is the curvature radius of the image side surface of the lens closest to the image side in the lens 100.

[0094] Correspondingly, when the curvature radius of the image side surface of the first lens 10 is located in the range of 20.1mm to 400mm, the image side surface of the first lens 10 can be prevented from being too flat, which is beneficial to aberration correction. In addition, the image side surface of the first lens 10 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0095] 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, 55mm, 60mm, 61.698mm, 65mm, 66mm, 69mm, 70mm, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, and the like.

[0096] 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 lens closest to the object side in the lens 100, and EFL is the focal length of the lens 100.

[0097] Correspondingly, when the ratio of the radius of curvature of the object side surface of the lens closest to the object side in the lens 100 to the focal length of the lens 100 is located in the range of -20 to -2, the object side surface of the lens closest to the object side 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 lens closest to the object side in the lens 100 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0098] 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, and the like.

[0099] In some possible implementation manners, the lens 100 can also satisfy 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 in the lens 100.

[0100] Correspondingly, when the radius of curvature of the object side surface of the lens closest to the object side in the lens 100 is located in the range of -500mm to 500mm, the object side surface of the lens closest to the object side 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 lens closest to the object side in the lens 100 can also be prevented from being too protruding, which is beneficial to packaging, transportation or assembly.

[0101] The specific value of R2 is not limited here. The value of R2 can be -500mm, -450mm, -300mm, -180mm, -150mm, -140mm, -135mm, -130mm, -125mm, -120mm, -115mm, -110mm, -105mm, -100mm, -95mm, -90mm, -85mm, -80mm, -75mm, -70mm, -65mm, -60mm, -55mm, -50mm, 50mm, 100mm, 150mm, 250mm, 350mm, 400mm, 450mm, 500mm, and the like.

[0102] In some possible implementation manners, the lens 100 can also satisfy the relationship: 28mm≤BFL≤33mm, where BFL is the back focal length of the lens 100.

[0103] Correspondingly, when the back focal length of the lens 100 is located in the range of 28mm to 33mm, the optical path of the lens 100 can be prevented from being too long or too short, which can improve the application range of the lens 100. The optical path of the lens 100 being too long is not conducive to design. The optical path of the lens 100 being too short is not conducive to the setting of the rear-end optical path.

[0104] The rear focal length of the lens 100 is not limited herein. 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.

[0105] In some possible implementation manners, the lens 100 can further include a movable barrel (not shown in the figure) and a fixed barrel (not shown in the figure), the movable barrel is configured 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.

[0106] In this way, by controlling the movement of the movable barrel relative to the fixed barrel, the focusing of the lens 100 can be achieved, 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.

[0107] 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 to the fixed barrel.

[0108] The lens 100 and the projection device 400 will be described in detail below in combination with specific embodiments.

[0109] FIG. 5 is a structural schematic diagram of a projection device provided in an embodiment of the present application.

[0110] Referring to FIG. 5, the projection device 400 provided in the embodiment can include the modulation unit 200, the cover glass 300, and the lens 100. The cover glass 300 is arranged between the modulation unit 200 and the lens 100 along the 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 also be less than or more than two.

[0111] Continuing to refer to FIG. 5, the lens 100 includes the first lens 10 and the 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 includes the first lens group 30, the diaphragm 40, and the second lens group 50 arranged from the image side to the object side, and the first lens group 30 is located between the diaphragm 40 and the first lens 10 along the direction from the image side to the object side, and the second lens group 50 is arranged between the diaphragm 40 and the modulation unit 200.

[0112] Continuing to refer to FIG. 5, the first lens group 30 includes, arranged in order from the image side to the object side, a second lens 31, a third lens 32, and a fourth lens 33, the second lens 31 being closest to the first lens 10, and the fourth lens 33 being closest to the stop 40.

[0113] Continuing to refer to FIG. 5, the second lens group 50 can include, arranged in order from the image side to the object side, a fifth lens 51, a sixth lens 52, a seventh lens 55, and an eighth lens 54, the fifth lens 51 being closest to the stop 40, the fifth lens 51 and the sixth lens 52 constituting a cemented lens, and the eighth lens 54 being closest to the modulation unit 200.

[0114] 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, the sixth lens 52 has positive refractive power, the cemented lens constituted by the fifth lens 51 and the sixth lens 52 has negative refractive power, and 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.

[0115] 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, satisfying 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, satisfying the requirement.

[0116] 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, i.e., the back focal length BFL of the lens 100 is 31.85 mm, which is greater than 28 mm and less than 33 mm, satisfying the requirement.

[0117] 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, satisfying 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, satisfying the requirement.

[0118] 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, satisfying the requirement.

[0119] Table 1 shows optical parameters of each optical element in the projection device 400 provided by the embodiments of the present application.

[0120] wherein R is the radius of curvature of the optical element (such as a lens or cover glass 300, etc.) at the position corresponding to the optical axis, TH is the thickness of the optical element in the direction X along the optical axis, Nd is the refractive index of the optical element for d-line illumination, and Vd is the Abbe number of the optical element.

[0121] 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), and ImgH is the imaging surface.

[0122] Table 2 shows the conjugate values under different projection distance conditions of L / D.

[0123] 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.

[0124] As can be seen from Table 2, by controlling the movement of the first lens 10 relative to the fixed lens group 20 along the optical axis X by different distances, the distance between the image side surface of the first lens 10 and the image (projection surface) changes. For example, when D changes from 2.830 mm to 1.613 mm, the corresponding L also changes from 110.000 mm to 130.000 mm.

[0125] Table 3 shows the optical parameters of the lens 100 in FIG. 5.

[0126] EFL = EFL1 + EFL2 + BFL, wherein EFL is the focal length of the lens 100, EFL1 is the focal length of the four lenses of 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 the lens 100, R1 is the radius of curvature of the image side surface of the first lens 10, R2 is the radius of curvature of the object side surface of the lens closest to the object side in the 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 composed of 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.

[0127] FIG. 6 is a spherical aberration diagram of the lens 100 in FIG. 5. In FIG. 6, the ordinate represents a normalized pupil coordinate, and the abscissa represents an aberration in the axial direction, in millimeters. In FIG. 6, the three curves respectively correspond to the axial aberration curves of light with a wavelength of 625 nm, light with a wavelength of 550 nm, and light with a wavelength of 455 nm after passing through the lens 100 of the present embodiment. As can be seen from FIG. 6, in the present embodiment, the axial aberration is controlled within a very small range, and a good correction is obtained.

[0128] FIG. 7 is a field curvature diagram of the lens 100 in FIG. 5, and FIG. 8 is a distortion diagram of the lens 100 in FIG. 5. In FIG. 7, S represents the field curvature value of light with a wavelength of 550 nm on the meridional image surface, and T represents the field curvature value of light with a wavelength of 550 nm on the sagittal image surface. In FIG. 8, the solid line represents the distortion value of light with a central wavelength of 550 nm after passing through the lens 100 of the present embodiment. As can be seen from FIGS. 7 and 8, the lens 100 provided in the present embodiment controls the field curvature and the distortion within the corresponding ranges, and can meet the use requirements.

[0129] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, can be fixed connection, can also be indirect connection through an intermediate medium, can be the communication inside two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0130] 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 a limitation of 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 and limited.

[0131] The terms "first", "second", "third", "fourth" and the like in the description and in the claims of the present application, and above-described drawings, if any, are used to distinguish between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the use of the terms so construed herein can be interchanged, under appropriate circumstances, and that the embodiments of the present application described herein are capable of

[0132] The term "a plurality" or "a plurality of" means two or more. The term "and / or" herein is merely an associative relationship of the associated objects, and means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " herein generally means that the front and rear associated objects are in an "or" relationship; in the formula, the character " / " means that the front and rear associated objects are in a "division" relationship.

[0133] It can be understood that various numerical numbers involved in the embodiments of the present application are only for convenient differentiation, and do not limit the scope of the embodiments of the present application.

[0134] It can be understood that the size of the serial number of each process in the embodiments of the present application does not mean the order of execution, and the execution order of each process should be determined according to 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