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 group, a diaphragm and a second lens group which are arranged from an image side to an object side. The first lens group comprises at least four lenses, and along the direction from the image side to the object side, the first lens closest to the image side in the first lens group has positive focal power, the second lens has negative focal power, the third lens has negative focal power, and the fourth lens has positive focal power. The second lens group comprises at least four lenses, and along the direction from the image side to the object side, the first lens closest to the diaphragm in the second lens group 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. The lens provided by the embodiment of the invention is high in definition and reliability, and can meet the projection requirements of high definition and high reliability.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of optical technologies, and in particular, to a lens, a projection device, a display device, and a vehicle. Background Art

[0002] With the development of intelligent vehicle technologies, an augmented reality head-up display (AR-HUD) has gradually become a mainstream configuration in automotive intelligent cockpits. 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 information such as the running speed, navigation, and signal lights of the vehicle while looking at the road surface, without having to look down at the instrument panel or the central control display below the steering wheel, thereby greatly improving the braking reaction time in case of an emergency and enhancing driving safety. In related technologies, an in-vehicle head-up display includes a projection optical engine and a projection lens. The projection optical engine modulates information such as navigation and instruments to be displayed into a light beam and projects it onto the projection lens, and the projection lens projects the image light beam onto the projection surface, so that the real-time road surface is fused with the information to be displayed. However, the existing projection lenses have the problem of low clarity. Summary of the Invention

[0003] The embodiments of the present application provide a lens, a projection device, a display device, and a vehicle, which can improve the clarity of the lens.

[0004] In the first aspect of the present application, a lens is provided, which includes a first lens group, a diaphragm, and a second lens group arranged from the image side to the object side. The first lens group includes at least four lenses. Along the direction from the image side to the object side, the first lens closest to the image side in the first lens group has a positive optical power, the second lens has a negative optical power, the third lens has a negative optical power, and the fourth lens has a positive optical power. The second lens group includes at least four lenses. Along the direction from the image side to the object side, the first lens closest to the diaphragm in the second lens group has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, and the fourth lens has a positive optical power.

[0005] Since the optical power structure of the four lenses closest to the image side in the first lens group is a positive-negative-negative-positive structure, and the optical power structure of the four lenses closest to the diaphragm in the second lens group is a negative-positive-positive-positive structure, the imaging ability of the lens can be improved, and further the clarity of the lens can be improved to meet the requirements of a high-clarity lens. In addition, the reliability of the lens can also be improved to meet the requirements of a high-reliability lens.

[0006] In a possible implementation manner, the lens satisfies the relationship: 13.5 mm ≤ EFL ≤ 14.5 mm, where EFL is the focal length of the lens.

[0007] When the focal length of the lens is between 13.5 mm and 14.5 mm, the imaging ability of the lens can be further improved, and the clarity of the lens can be further enhanced.

[0008] In a possible implementation, the lens satisfies the relational expression: 115 mm ≤ L ≤ 150 mm. Along the direction from the image side to the object side, L refers to the distance between the lens element closest to the image side in the lens and the image.

[0009] When the distance between the lens element closest to the image side in the lens and the image is between 115 mm and 150 mm, the clarity can be further improved to meet the requirements of a high-definition lens.

[0010] In a possible implementation, the first lens group satisfies the relational expression: -58 mm ≤ EFL1 ≤ -40 mm, where EFL1 refers to the focal length of the first lens group.

[0011] When the focal length of the first lens group is between -58 mm and -40 mm, the imaging ability of the lens can be further improved, and the clarity can be further enhanced. Additionally, the compactness of the lens can be improved.

[0012] In a possible implementation, the lens satisfies the relational expression: 2 ≤ R1 / EFL ≤ 5, where R1 is the radius of curvature of the image side surface of the lens element closest to the image side in the 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 lens element closest to the image side in the lens to the focal length of the lens is between 2 and 5, it is possible to avoid the image side surface of the lens element closest to the image side in the lens from being too flat, which is beneficial for aberration correction. Additionally, it is possible to avoid the image side surface of the lens element closest to the image side in the lens from being too convex, which is beneficial for packaging, transportation, or assembly.

[0014] In a possible implementation, the lens satisfies the relational expression: 26 mm ≤ R1 ≤ 70 mm, where R1 is the radius of curvature of the image side surface of the lens element closest to the image side in the lens.

[0015] When the radius of curvature of the image side surface of the lens element closest to the image side in the lens is between 26 mm and 70 mm, it is possible to avoid the image side surface of the lens element closest to the image side in the lens from being too flat, which is beneficial for aberration correction. Additionally, it is possible to avoid the image side surface of the lens element closest to the image side in the lens from being too convex, which is beneficial for packaging, transportation, or assembly.

[0016] In a possible implementation, the second lens group satisfies the relational expression: 19 mm ≤ EFL2 ≤ 25 mm, where EFL2 refers to the focal length of the second lens group.

[0017] When the focal length of the second lens group is between 19 mm and 25 mm, the imaging ability of the lens can be further improved, and the clarity can be further enhanced. Additionally, the compactness of the lens can be increased. Moreover, the matching degree between the chief ray angle of the rear-end chip (such as a projection chip) and the chief ray angle of the lens can be improved to enhance the optical efficiency.

[0018] In a possible implementation, the lens satisfies the relation: -10 ≤ R2 / EFL ≤ -3, where 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.

[0019] 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 between -10 and -3, it can prevent the object side surface of the lens closest to the object side from being too flat, which is beneficial to aberration correction. Additionally, it can prevent the object side surface of the lens closest to the object side from being too convex, which is beneficial to packaging, transportation, or assembly.

[0020] In a possible implementation, the lens satisfies the relation: -140 mm ≤ R2 ≤ -50 mm, where R2 is the curvature radius of the object side surface of the lens closest to the object side.

[0021] When the curvature radius of the object side surface of the lens closest to the object side is between -140 mm and -50 mm, it can prevent the object side surface of the lens closest to the object side from being too flat, which is beneficial to aberration correction. Additionally, it can prevent the object side surface of the lens closest to the object side from being too convex, which is beneficial to packaging, transportation, or assembly.

[0022] In a possible implementation, the lens satisfies the relation: 28 mm ≤ BFL ≤ 33 mm, where BFL is the back focal length of the lens.

[0023] When the back focal length of the lens is between 28 mm and 33 mm, it can prevent the optical path of the lens from being too long or too short, and can improve the application range of the lens. Among them, 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.

[0024] In a possible implementation, the first lens group includes a first lens with a positive focal power, a second lens with a negative focal power, a third lens with a negative focal power, and a fourth lens with a positive focal power arranged from the image side to the object side. The first lens is closest to the image side, and the fourth lens is closest to the aperture. The second lens group includes a fifth lens with a negative focal power, a sixth lens with a positive focal power, a seventh lens with a positive focal power, and an eighth lens with a positive focal power arranged from the image side to the object side. The fifth lens is closest to the aperture, and the eighth lens is closest to the object side.

[0025] When the first lens group is composed of a first lens with a positive focal power, a second lens with a negative focal power, a third lens with a negative focal power, and a fourth lens with a positive focal power, and the second lens group is composed of a fifth lens with a negative focal power, a sixth lens with a positive focal power, a seventh lens with a positive focal power, and an eighth lens with a positive focal power, the imaging ability of the lens can be improved to meet the lens requirements of high definition and high reliability. In addition, the number of lenses can be reduced to reduce the cost of the lens.

[0026] A second aspect of the present application provides a projection device, including a display unit and a lens as described in any one of the first aspects, and the second lens group of the lens is close to the display unit. Among them, the display unit is used to emit image light to the lens.

[0027] A third aspect of the present application provides a display device, including an imaging module and a projection device as described in the second aspect. Among them, the imaging module generates a target image based on the image light emitted by the projection device.

[0028] A fourth aspect of the present application provides a vehicle, including a display device as described in the third aspect.

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

[0030] In a possible implementation manner, the vehicle further includes a windshield, and the image light emitted by the display device is incident on the windshield, and the windshield reflects the image light to the human eye. Description of the Drawings

[0031] Figure 1A It is a schematic structural diagram of the usage scenario of the display device provided by the embodiment of the present application;

[0032] Figure 1B It is a schematic structural diagram of a display device installed on a vehicle provided by the embodiment of the present application;

[0033] Figure 2 It is a schematic structural diagram of a lens provided by the embodiment of the present application;

[0034] Figure 3 It is a schematic structural diagram of the first projection device provided by the first embodiment of the present application;

[0035] Figure 4 It is Figure 3 the spherical chromatic aberration diagram of the lens in;

[0036] Figure 5 It is Figure 3 the astigmatism field curvature diagram of the lens in;

[0037] Figure 6 It is Figure 4 the distortion diagram of the lens in;

[0038] Figure 7 Schematic diagram of the structure of the second projection device provided in the second embodiment of the present application;

[0039] Figure 8 is Figure 7 spherical chromatic aberration diagram of the lens in

[0040] Figure 9 is Figure 7 astigmatism field curvature diagram of the lens in

[0041] Figure 10 is Figure 7 distortion diagram of the lens in

[0042] Figure 11 Schematic diagram of the structure of the third projection device provided in the third embodiment of the present application;

[0043] Figure 12 is Figure 11 spherical chromatic aberration diagram of the lens in

[0044] Figure 13 is Figure 11 astigmatism field curvature diagram of the lens in

[0045] Figure 14 is Figure 11 distortion diagram of the lens in

[0046] Figure 15 Schematic diagram of the structure of the fourth projection device provided in the fourth embodiment of the present application;

[0047] Figure 16 is Figure 15 spherical chromatic aberration diagram of the lens in

[0048] Figure 17 is Figure 15 astigmatism field curvature diagram of the lens in

[0049] Figure 18 is Figure 15 distortion diagram of the lens in

[0050] Figure 19 Schematic diagram of the structure of the fifth projection device provided in the fifth embodiment of the present application;

[0051] Figure 20 is Figure 19 spherical chromatic aberration diagram of the lens in

[0052] Figure 21 is Figure 19 astigmatism field curvature diagram of the lens in

[0053] Figure 22 is Figure 19The distortion diagram of the lens in

[0054] Explanation of reference numerals:

[0055] 100, lens;

[0056] 10, first lens group; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens;

[0057] 20, aperture stop;

[0058] 30, second lens group; 31, fifth lens; 32, sixth lens; 33, seventh lens; 34, eighth lens;

[0059] 200, modulation unit

[0060] 300, cover glass;

[0061] 400, projection device;

[0062] 500, display device;

[0063] 600, imaging module;

[0064] 700, display unit; 710, light source. Detailed implementation manners

[0065] The terms used in the implementation manners part of this application are only used to explain the specific embodiments of this application, and are not intended to limit this application.

[0066] For ease of understanding, first, relevant technical terms involved in the embodiments of this application are explained and described.

[0067] Focal length, also known as focal length, is a measure of the convergence or divergence of light in an optical system. It refers to the perpendicular distance from the optical center of a lens or lens group to the focal plane when an infinitely distant scene forms a clear image on the focal plane through the lens or lens group.

[0068] Image side: Taking 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.

[0069] 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 of the lens.

[0070] Back focal length (abbreviated as BFL) is defined as the distance from the lens closest to the imaging surface in the lens to the modulation unit.

[0071] Optical power characterizes the refractive ability of a lens for an incident parallel light beam.

[0072] Positive optical power indicates that the lens has a positive focal length and has the effect of converging light rays.

[0073] Negative optical power indicates that the lens has a negative focal length and has the effect of diverging light rays.

[0074] An aperture is a device used to control the amount of light passing through the lens and entering the interior of the electronic device. It is usually inside the lens, and the size of the aperture is expressed by the F# (F-number) value.

[0075] The aperture number F# is the relative value obtained by dividing the focal length of the lens by the diameter of the lens aperture (the reciprocal of the relative aperture). The smaller the F# value, the more light enters in the same unit of time.

[0076] Cover glass (CG) is used to protect the modulation unit.

[0077] The modulation unit is used to modulate the light beam emitted by the light source to generate the image light directed towards the lens.

[0078] The projection chip is used to modulate the light beam emitted by the light source to generate the image light directed towards the lens.

[0079] Digital micromirror devices (DMD) are used to reflect light to form an image.

[0080] Liquid crystal on silicon (LCOS) is used to reflect light to form an image.

[0081] Micro-electro-mechanical system (MEMS) can reflect light to form an image.

[0082] Axial chromatic aberration, also known as longitudinal chromatic aberration or position chromatic aberration, is a phenomenon where a parallel beam of light rays parallel to the optical axis converges at different positions before and after passing through the lens. This aberration is called position chromatic aberration or axial chromatic aberration. This is because the lens forms images of light of different wavelengths at different positions, resulting in the imaging planes of different colors not completely coinciding when the final image is formed, and the polychromatic light spreads to form chromatic dispersion.

[0083] Distortion, also known as aberration, refers to the degree of distortion of the image formed by an optical system with respect to the object itself. Distortion is caused by the influence of the diaphragm aberration. The height of the chief ray of different fields passing through the optical system does not equal the ideal image height at the Gaussian image plane, and the difference between the two is the distortion. Therefore, distortion only changes the imaging position of off-axis object points on the ideal plane, causing the shape of the image to be distorted, but does not affect the clarity of the image.

[0084] In recent years, an augmented reality (AR) head-up display (AR-HUD) has been proposed, which can fuse the AR effect projected and displayed by the HUD with real road surface information, enhance the driver's acquisition of road surface information, and realize functions such as AR navigation and AR warning. In related technologies, the augmented display head-up display includes a projection optical engine and a projection lens. The projection optical engine is used to modulate information such as navigation and instrument to be displayed into an imaging light beam and shoot it at the projection lens, and the projection lens projects the imaging light beam onto a projection surface to form an image, so that the real-time road surface is fused with the information to be displayed. However, the existing projection lenses have problems such as low clarity and low reliability, resulting in poor imaging quality and unable to meet the projection requirements of high clarity and high reliability.

[0085] In view of this, embodiments of the present application provide a lens 100, a projection device 400, a display device 500, and a vehicle. The lens 100 has strong imaging ability and can improve the clarity of the image to meet the projection requirements of high clarity. In addition, the lens 100 has high reliability and can meet the projection requirements of high reliability.

[0086] The vehicle provided by the embodiments of the present application may include, but is not limited to, a sedan, a truck, a motorcycle, a bus, a ship, an airplane, a helicopter, a lawn mower, a recreational vehicle, a playground vehicle, a construction vehicle, a tram, a golf cart, a train, or a trolley, etc. For example, in the embodiments of the present application, a sedan is taken as an example of the above vehicle for illustration. Therefore, the vehicle may include components such as a windshield and an instrument panel.

[0087] The display device 500 provided by the embodiments of the present application may be a display, a television, a head-up display, etc. For example, in the embodiments of the present application, a head-up display is taken as an example of the above display device 500 for illustration, as Figure 1A shown, Figure 1A is a schematic structural diagram of the usage scenario of the display device provided by the embodiments of the present application. Among them, the head-up display (abbreviation: HUD) can project navigation information, instrument information, etc. within the driver's forward field of view, avoiding the driver from looking down at this information, thus affecting driving safety. After the image projected by the HUD is reflected by the windshield (windshield), a virtual image is formed outside the vehicle, and these virtual images can be superimposed on the real environment outside the vehicle, so that the driver can obtain the visual effect of augmented reality (AR), thereby realizing functions such as AR navigation, adaptive cruise, and lane departure warning. Among them, the types of HUD include, but are not limited to, windshield (W)-HUD, augmented reality head-up display (AR-HUD), etc.

[0088] Figure 1BSchematic diagram of a structure in which a display device provided by an embodiment of the present application is installed on a vehicle.

[0089] Refer to Figure 1B As shown, the display device 500 can be installed in the instrument panel of the vehicle to achieve a hidden installation. In addition, the image light emitted by the display device 500 can be incident on the windshield, and the windshield can reflect the image light to the human eye, enabling the human eye to see a virtual image located outside the windshield.

[0090] Continue to refer to Figure 1B As shown, the display device 500 can include a projection device 400 and an imaging module 600. Among them, the imaging module 600 can generate a target image based on the image light emitted by the projection device 400.

[0091] Among them, the imaging module 600 can reflect the image light emitted by the projection device 400 to the windshield, and the windshield reflects the image light to the human eye to form a target image.

[0092] Regarding the specific structure of the imaging module 600, no limitation is imposed here. Exemplarily, as Figure 2 shown, the imaging module 600 can include a curved mirror, and the curved mirror is used to reflect the image light emitted by the projection device 400 to the windshield, and the windshield 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.

[0093] Refer to Figure 1B As shown, 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 transmits the image light to the imaging module 600.

[0094] Among them, the display unit 700 can include a light source 710 and a modulation unit 200. The light source 710 is used to generate a light beam carrying the image data of the input image. The modulation unit 200 is used to modulate the light beam generated by the light source 710 according to the image data and generate image light that is incident on the lens 100.

[0095] Regarding the specific structure of the modulation unit 200, no limitation is imposed here. Exemplarily, the modulation unit 200 can be a projection chip. Among them, the projection chip can be a reflective spatial light modulator and has the function of changing the polarization direction of the incident linearly polarized light, such as LCoS. Or, the projection chip can also be a reflective spatial light modulator and does not have the function of changing the polarization direction of the incident linearly polarized light, such as MEMS or DMD. Or, the projection chip can also be a transmissive spatial light modulator, such as LCD, etc.

[0096] In some possible implementations, the projection device 400 may further include a cover glass 300. Along the direction from the image side to the object side, the cover glass 300 is disposed between the lens 100 and the modulation unit 200, and the cover glass 300 can protect the modulation unit 200. The number of the cover glass 300 may be one or more, which is not limited herein. When the number of the cover glass 300 is more than one, all the cover glass 300 are disposed between the modulation unit 200 and the lens 100.

[0097] Next, the lens 100 provided by the embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0098] Figure 2 It is a schematic structural diagram of a lens provided by the embodiments of the present application. Refer to Figure 2 As shown, the lens 100 of the embodiments of the present application includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. The first lens group 10 is close to the image side, and the second lens group 30 is close to the object side. Among them, the first lens group 10 includes at least four lenses. For example Figure 2 As shown, the first lens group 10 may include four lenses. Of course, the number of lenses in the first lens group 10 may also be more than four. Along the direction from the image side to the object side, the first lens closest to the image side in the first lens group 10 has a positive optical power, the second lens has a negative optical power, the third lens has a negative optical power, and the fourth lens has a positive optical power. The second lens group 30 includes at least four lenses. For example Figure 2 As shown, the second lens group 30 may include four lenses. Of course, the number of lenses in the second lens group 30 may also be more than or less than four. Along the direction from the image side to the object side, the first lens closest to the diaphragm 20 in the second lens group 30 has a negative optical power, the second lens has a positive optical power, the third lens has a positive optical power, and the fourth lens has a positive optical power.

[0099] Combined with Figure 2 It can be seen that since the optical power structure of the four lenses closest to the image side in the first lens group 10 is a positive-negative-negative-positive structure, and the optical power structure of the four lenses closest to the diaphragm 20 in the second lens group 30 is a negative-positive-positive-positive structure, the imaging ability of the lens 100 can be improved, and further the clarity of the lens 100 can be improved to meet the requirements of a high-definition lens 100. In addition, the reliability of the lens 100 can also be improved to meet the requirements of a high-reliability lens 100.

[0100] There is no limitation on the number of lenses in the first lens group 10 and the number of lenses in the second lens group 30. Exemplarily, for example Figure 2As shown in the figure, both the first lens group 10 and the second lens group 30 are composed of four lenses. Among them, the first lens group 10 may include a first lens 11 with a positive focal power, a second lens 12 with a negative focal power, a third lens 13 with a negative focal power, and a fourth lens 14 with a positive focal power, arranged from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the aperture 20. The second lens group 30 may include a fifth lens 31 with a negative focal power, a sixth lens 32 with a positive focal power, a seventh lens 33 with a positive focal power, and an eighth lens 34 with a positive focal power, arranged from the image side to the object side. The fifth lens 31 is closest to the aperture 20, and the eighth lens 34 is closest to the object side.

[0101] When the first lens group 10 is composed of a first lens 11 with a positive focal power, a second lens 12 with a negative focal power, a third lens 13 with a negative focal power, and a fourth lens 14 with a positive focal power, and the second lens group 30 is composed of a fifth lens 31 with a negative focal power, a sixth lens 32 with a positive focal power, a seventh lens 33 with a positive focal power, and an eighth lens 34 with a positive focal power, the lens 100 is composed of eight lenses. The eight lenses and the aperture 20 form a front-four and back-four structure, which can improve the imaging ability of the lens 100 to meet the requirements of high-definition and high-reliability of the lens 100. In addition, the number of lenses can be reduced to reduce the cost of the lens 100.

[0102] It should be noted that when the number of lenses in the first lens group 10 is at least five, the lenses in the first lens group 10 except the four lenses closest to the image side are arranged between the fourth lens closest to the image side and the aperture 20, that is, between the fourth lens 14 and the aperture 20. Similarly, when the number of lenses in the second lens group 30 is at least five, the lenses in the second lens group 30 except the four lenses closest to the aperture 20 are arranged between the fourth lens closest to the aperture 20 and the object side (or the modulation unit 200), that is, between the eighth lens 34 and the object side (or the modulation unit 200).

[0103] In some possible implementation manners, the lens 100 may further satisfy the relational expression: 13.5mm ≤ EFL ≤ 14.5mm, where EFL is the focal length of the lens 100.

[0104] Correspondingly, when the focal length of the lens 100 is between 13.5mm and 14.5mm, the imaging ability of the lens 100 can be further improved, and the clarity of the lens 100 can be further improved.

[0105] There is no restriction on the specific value of the focal length of the lens 100. Among them, the focal length of the lens 100 can be 13.5mm, 13.6mm, 13.99mm, 14.0mm, 14.1mm, 14.2mm, 14.3mm, 14.4mm, 14.5mm, etc.

[0106] In some possible implementation manners, the lens 100 can further satisfy the relational expression: 115mm ≤ L ≤ 150mm. Along the direction from the image side to the object side, L refers to the distance between the lens closest to the image side in the lens 100 and the image (as Figure 2 shown by L in

[0107] Accordingly, when the distance between the lens closest to the image side in the lens 100 and the image is between 115mm and 150mm, the clarity can be further improved to meet the requirements of the high - definition lens 100.

[0108] There is no restriction on the specific value of L. Among them, L can be 115mm, 120mm, 121mm, 125mm, 128mm, 130mm, 131.5mm, 135mm, 139mm, 140mm, 143mm, 145.5mm, 148mm, 150mm, etc.

[0109] In some possible implementation manners, the first lens group 10 can further satisfy the relational expression: - 58mm ≤ EFL1 ≤ - 40mm, where EFL1 refers to the focal length of the first lens group 10.

[0110] Accordingly, when the focal length of the first lens group 10 is between - 58mm and - 40mm, the imaging ability of the lens 100 can be further improved, and the clarity can be further improved. In addition, the compactness of the lens 100 can also be improved.

[0111] There is no restriction on the specific value of the focal length of the first lens group 10. Among them, the focal length of the first lens group 10 can be - 58mm, - 57.985mm, - 57.5mm, - 55mm, - 53.6998mm, - 50mm, - 49mm, - 48mm, - 47.5mm, - 47mm, - 46mm, - 45mm, - 44mm, - 43.68mm, - 42mm, - 41.5mm, - 41.35mm, - 40mm, etc.

[0112] In some possible implementation manners, the lens 100 can further satisfy the relational expression: 2 ≤ R1 / EFL ≤ 5, where R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, and EFL refers to the focal length of the lens 100.

[0113] Correspondingly, when the ratio of the radius of curvature of the image side surface of the lens closest to the image side in the lens 100 to the focal length of the lens 100 is between 2 and 5, it is possible to avoid the image side surface of the lens closest to the image side in the lens 100 from being too flat, which is beneficial to aberration correction. In addition, it is also possible to avoid the image side surface of the lens closest to the image side in the lens 100 from being too convex, which is beneficial to packaging, transportation or assembly.

[0114] There is no limit on the specific value of the ratio of R1 / EFL. Among them, the ratio of R1 / EFL can be 2, 2.5, 2.8, 3, 3.1, 3.5, 3.987, 4, 4.1, 4.5, 4.9 or 5, etc.

[0115] In some possible implementation manners, the lens 100 can further satisfy the relational expression: 26 mm ≤ R1 ≤ 70 mm, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens 100.

[0116] Correspondingly, when the radius of curvature of the image side surface of the lens closest to the image side in the lens 100 is between 26 mm and 70 mm, it is possible to avoid the image side surface of the lens closest to the image side in the lens 100 from being too flat, which is beneficial to aberration correction. In addition, it is also possible to avoid the image side surface of the lens closest to the image side in the lens 100 from being too convex, which is beneficial to packaging, transportation or assembly.

[0117] There is no limit on the specific value of R1. Among them, the value of R1 can be 26 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 61.698 mm, 65 mm, 66 mm, 69 mm or 70 mm, etc.

[0118] In some possible implementation manners, the second lens group 30 can further satisfy the relational expression: 19 mm ≤ EFL2 ≤ 25 mm, where EFL2 refers to the focal length of the second lens group 30.

[0119] Correspondingly, when the focal length of the second lens group 30 is between 19 mm and 25 mm, the imaging ability of the lens 100 can be further improved, and the clarity can be further improved. In addition, the compactness of the lens 100 can also be improved. In addition, the matching degree of the chief ray angle of the rear-end chip and the chief ray angle of the lens 100 can be improved to improve the optical efficiency. Among them, the rear-end chip refers to the modulation unit 200 closest to the second lens group 30.

[0120] There is no limit on the specific value of the focal length of the first lens group 10. Among them, the focal length of the second lens group 30 can be 19 mm, 19.5 mm, 20 mm, 21.5 mm, 22 mm, 22.5 mm, 23 mm, 23.509 mm, 24 mm, 24.5 mm, 25 mm, 25.5 mm or 26 mm, etc.

[0121] In some possible implementations, the lens 100 can also satisfy the relational expression: -10 ≤ R2 / EFL ≤ -3, where R2 is the radius of curvature 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.

[0122] 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 between -10 and -3, it is possible to avoid the object side surface of the lens closest to the object side in the lens 100 from being too flat, which is beneficial to aberration correction. In addition, it is also possible to avoid the object side surface of the lens closest to the object side in the lens 100 from being too convex, which is beneficial to packaging, transportation or assembly.

[0123] There is no limitation on the specific ratio of R2 / EFL. Among them, the ratio of R2 / EFL can be -10, -9.5, -9, -8, -8.5, -8, -7.5, -7, -6.5, -6, -5.5, -5, -4.5, -4, -3.5 or -3, etc.

[0124] In some possible implementations, the lens 100 can also satisfy the relational expression: -140 mm ≤ R2 ≤ -50 mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens 100.

[0125] Correspondingly, when the radius of curvature of the object side surface of the lens closest to the object side in the lens 100 is between -140 mm and -50 mm, it is possible to avoid the object side surface of the lens closest to the object side in the lens 100 from being too flat, which is beneficial to aberration correction. In addition, it is also possible to avoid the object side surface of the lens closest to the object side in the lens 100 from being too convex, which is beneficial to packaging, transportation or assembly.

[0126] There is no limitation on the specific value of R2. Among them, the value of R2 can be -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 or -50 mm, etc.

[0127] In some possible implementations, the lens 100 can also satisfy the relational expression: 28 mm ≤ BFL ≤ 33 mm, where BFL is the back focal length of the lens 100.

[0128] Correspondingly, when the back focal length of the lens 100 is between 28 mm and 33 mm, it is possible to avoid the optical path of the lens 100 from being too long or too short, and the application range of the lens 100 can be improved. Among them, if the optical path of the lens 100 is too long, it is not conducive to design. If the optical path of the lens 100 is too short, it is not conducive to the setting of the rear optical path.

[0129] There is no limitation on the specific value of the back focal length of the lens 100 here. Among them, the focal length of the lens 100 can be 28mm, 28.6mm, 29mm, 29.5mm, 29.887mm, 30mm, 30.5mm, 31mm, 31.5mm, 32mm, 32.5mm or 33mm, etc.

[0130] The lens 100 and the projection device 400 provided by the embodiments of the present application will be described in detail below with reference to specific embodiments.

[0131] Figure 3 It is a schematic structural diagram of the first projection device provided in the first embodiment of the present application.

[0132] Combined with Figure 3 It can be seen that the projection device 400 provided in the first embodiment may include a modulation unit 200, a cover glass 300, and a lens 100. Among them, the lens 100 includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. Along the direction from the image side to the object side, the second lens group 30 is disposed between the diaphragm 20 and the modulation unit 200, and the cover glass 300 is disposed between the modulation unit 200 and the lens 100. The number of the cover glasses 300 is three, and the three cover glasses 300 are arranged at intervals along the direction from the image side to the object side.

[0133] Combined with Figure 3 It can be seen that the first lens group 10 may include a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the diaphragm 20. Among them, the first lens 11 has a positive optical power, and the focal length f1 of the first lens 11 = 33.05. The second lens 12 has a negative optical power, and the focal length f2 of the second lens 12 = -17.32. The third lens 13 has a negative optical power, and the focal length f3 of the third lens 13 = -35.85. The fourth lens 14 has a positive optical power, and the focal length f4 of the fourth lens 14 = 54.67.

[0134] Combined with Figure 3It can be known that the second lens group 30 may include a fifth lens 31, a sixth lens 32, a seventh lens 33, and an eighth lens 34 arranged in sequence from the image side to the object side. The fifth lens 31 is closest to the aperture 20. The fifth lens 31 and the sixth lens 32 form a cemented lens. The eighth lens 34 is closest to the modulation unit 200. Among them, the fifth lens 31 has a negative optical power, the sixth lens 32 has a positive optical power, the cemented lens formed by the fifth lens 31 and the sixth lens 32 has a positive optical power, and the focal length f56 of the cemented lens is 438.89. The seventh lens 33 has a positive optical power, and the focal length f7 of the seventh lens 33 is 101.32. The eighth lens 34 has a positive optical power, and the focal length f8 of the eighth lens 34 is 35.1757.

[0135] The lens closest to the image side in the lens 100 is the first lens 11. The radius of curvature of the image side surface of the first lens 11 is 32.67 mm, which is greater than 26 mm and less than 70 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 100 is 2.099, which is greater than 2 and less than 5, meeting the requirements. The focal length EFL1 of the first lens group 10 is -46.327 mm, which is greater than -58 mm and less than -40 mm, meeting the requirements.

[0136] The lens closest to the object side in the lens 100 is the eighth lens 34. The radius of curvature of the object side surface of the eighth lens 34 is -70.84 mm, which is greater than -140 mm and less than -50 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 34 to the focal length EFL of the lens 100 is -4.55, which is greater than -10 and less than -3, meeting the requirements. The focal length EFL2 of the second lens group 30 is 23.11 mm, which is greater than 19 mm and less than 25 mm, meeting the requirements.

[0137] In the direction from the image side to the object side, the distance between the object side surface of the eighth lens 34 and the modulation unit 200 is 30.81 mm, that is, the back focal length BFL of the lens 100 is 30.81 mm, which is greater than 28 mm and less than 33 mm, meeting the requirements.

[0138] The focal length EFL of the lens 100 is 14.2 mm, which is greater than 13.5 mm and less than 14.5 mm, meeting the requirements.

[0139] Table 1 shows the optical parameters of each optical element in the first projection device 400 provided in the first embodiment of the present application.

[0140]

[0141]

[0142] Among them, S1 is the image side of the first lens 11, S2 is the object side of the first lens 11, S3 is the image side of the second lens 12, S4 is the object side of the second lens 12, S5 is the image side of the third lens 13, S6 is the object side of the third lens 13, S7 is the image side of the fourth lens 14, S8 is the object side of the fourth lens 14, S9 is the aperture stop 20, S10 is the image side of the fifth lens 31, S11 is the cemented surface of the fifth lens 31 and the sixth lens 32, S12 is the object side of the sixth lens 32, S13 is the image side of the seventh lens 33, S14 is the object side of the seventh lens 33, S15 is the image side of the eighth lens 34, S16 is the object side of the eighth lens 34, S17 is the image side of the first cover glass 300 close to the lens 100, S18 is the object side of the first cover glass 300 close to the lens 100, S19 is the image side of the second cover glass 300 close to the lens 100, S20 is the object side of the second cover glass 300 close to the lens 100, S21 is the image side of the third cover glass 300 close to the lens 100, S22 is the object side of the third cover glass 300 close to the lens 100, S23 is the modulation unit 200, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0143] Among them, R is the radius of curvature of the optical element (such as a lens or the cover glass 300, etc.) at the corresponding position on the optical axis, TH is the surface thickness of the optical element in the optical axis direction, Nd is the refractive index of the d-line irradiating each optical element, and Vd is the Abbe number of the optical element.

[0144] Table 2 shows Figure 3 the optical parameters of the lens 100 in

[0145] f1 (mm) 33.049 R1 / EFL 2.099 f2 (mm) -17.317 R2 / EFL -4.55 f3 (mm) -35.848 EFL1 -46.327 f4 (mm) 54.665 EFL2 23.11 f56 (mm) 438.890 EFL (mm) 14.2 f7 (mm) 101.322 Fno 1.7 f8 (mm) 35.176 BFL (mm) 30.81

[0146] Among them, EFL is the focal length of the lens 100, EFL1 is the focal length of the first lens group 10, EFL2 is the focal length of the second lens group 30, Fno is the aperture of the lens 100, BFL is the back focal length of the lens 100, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 100, f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f3 is the focal length of the third lens 13, f4 is the focal length of the fourth lens 14, f56 is the focal length of the cemented lens composed of the fifth lens 31 and the sixth lens 3, f7 is the focal length of the seventh lens 33, and f8 is the focal length of the eighth lens 34.

[0147] Figure 4 is Figure 3 the spherical aberration diagram of the lens in Figure 4Among them, the vertical coordinate represents the normalized pupil coordinate, and the horizontal coordinate represents the aberration in the axial direction, with the unit of millimeters. In Figure 4 Among them, 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 this embodiment. From Figure 4 It can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0148] Figure 5 is Figure 3 the astigmatism field curvature diagram of the lens in Figure 6 is Figure 3 the distortion diagram of the lens in Figure 5 Among them, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 6 Among them, the solid line represents the distortion value of light with a central wavelength of 550 nm after passing through the lens 100 of this embodiment. Combining Figure 5 and Figure 6 it can be known that the lens 100 provided in this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0149] Figure 7 is the structural schematic diagram of the second projection device provided in the second embodiment of the present application.

[0150] Combining Figure 7 it can be known that the projection device 400 provided in the second embodiment may include a modulation unit 200, a cover glass 300, and a lens 100. Among them, the lens 100 includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. Along the direction from the image side to the object side, the second lens group 30 is arranged between the diaphragm 20 and the modulation unit 200, and the cover glass 300 is arranged between the modulation unit 200 and the lens 100. The number of cover glasses 300 is three, and the three cover glasses 300 are arranged at intervals along the direction from the object side to the image side.

[0151] Combining Figure 7 it can be known that the first lens group 10 may include a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the diaphragm 20. Among them, the first lens 11 has a positive optical power, and the focal length f1 of the first lens 11 = 60.01. The second lens 12 has a negative optical power, and the focal length f2 of the second lens 12 = -17.61. The third lens 13 has a negative optical power, and the focal length f3 of the third lens 13 = -50.70. The fourth lens 14 has a positive optical power, and the focal length f4 of the fourth lens 14 = 42.26.

[0152] Combination Figure 7 As can be seen, the second lens group 30 may include a fifth lens 31, a sixth lens 32, a seventh lens 33, and an eighth lens 34 arranged in sequence from the image side to the object side. The fifth lens 31 is closest to the aperture 20. The fifth lens 31 and the sixth lens 32 form a cemented lens. The eighth lens 34 is closest to the modulation unit 200. Among them, the fifth lens 31 has a negative optical power, the sixth lens 32 has a positive optical power, the cemented lens formed by the fifth lens 31 and the sixth lens 32 has a negative optical power, and the focal length f56 of the cemented lens is -2729.326. The seventh lens 33 has a positive optical power, and the focal length f7 of the seventh lens 33 is 80.60. The eighth lens 34 has a positive optical power, and the focal length f8 of the eighth lens 34 is 37.05.

[0153] The lens closest to the image side in the lens 100 is the first lens 11. The radius of curvature of the image side surface of the first lens 11 is 28.01 mm, which is greater than 26 mm and less than 70 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 100 is 2.0122, which is greater than 2 and less than 5, meeting the requirements. The focal length EFL1 of the first lens group 10 is -57.386 mm, which is greater than -58 mm and less than -40 mm, meeting the requirements.

[0154] The lens closest to the object side in the lens 100 is the eighth lens 34. The radius of curvature of the object side surface of the eighth lens 34 is -115.75 mm, which is greater than -140 mm and less than -50 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 34 to the focal length EFL of the lens 100 is -8.32, which is greater than -10 and less than -3, meeting the requirements. The focal length EFL2 of the second lens group 30 is 24.323 mm, which is greater than 19 mm and less than 25 mm, meeting the requirements.

[0155] In the direction from the image side to the object side, the distance between the object side surface of the eighth lens 34 and the modulation unit 200 is 30.83 mm, that is, the back focal length BFL of the lens 100 is 30.83 mm, which is greater than 28 mm and less than 33 mm, meeting the requirements.

[0156] The focal length EFL of the lens 100 is 13.91 mm, which is greater than 13.5 mm and less than 14.5 mm, meeting the requirements.

[0157] Table 3 shows the optical parameters of each optical element in the second projection device 400 provided in the second embodiment of the present application.

[0158]

[0159]

[0160] Among them, S1 is the image side of the first lens 11, S2 is the object side of the first lens 11, S3 is the image side of the second lens 12, S4 is the object side of the second lens 12, S5 is the image side of the third lens 13, S6 is the object side of the third lens 13, S7 is the image side of the fourth lens 14, S8 is the object side of the fourth lens 14, S9 is the aperture stop 20, S10 is the image side of the fifth lens 31, S11 is the cemented surface of the fifth lens 31 and the sixth lens 32, S12 is the object side of the sixth lens 32, S13 is the image side of the seventh lens 33, S14 is the object side of the seventh lens 33, S15 is the image side of the eighth lens 34, S16 is the object side of the eighth lens 34, S17 is the image side of the first cover glass 300 close to the lens 100, S18 is the object side of the first cover glass 300 close to the lens 100, S19 is the image side of the second cover glass 300 close to the lens 100, S20 is the object side of the second cover glass 300 close to the lens 100, S21 is the image side of the third cover glass 300 close to the lens 100, S22 is the object side of the third cover glass 300 close to the lens 100, S23 is the modulation unit 200, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0161] Among them, R is the radius of curvature of the optical element (such as a lens or the cover glass 300, etc.) at the corresponding position on the optical axis, TH is the surface thickness of the optical element in the optical axis direction, Nd is the refractive index of the d-line irradiated on each optical element, and Vd is the Abbe number of the optical element.

[0162] Table 4 shows Figure 7 the optical parameters of the lens 100 in

[0163] f1 (mm) 60.010 R1 / EFL 2.0122 f2 (mm) -17.614 R2 / EFL -8.32 f3 (mm) -50.703 EFL1 -57.386 f4 (mm) 42.259 EFL2 24.323 f56 (mm) -2729.326 EFL (mm) 13.91 f7 (mm) 80.598 Fno 1.9 f8 (mm) 37.052 BFL (mm) 30.83

[0164] Among them, EFL is the focal length of the lens 100, EFL1 is the focal length of the first lens group 10, EFL2 is the focal length of the second lens group 30, Fno is the aperture of the lens 100, BFL is the back focal length of the lens 100, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 100, f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f3 is the focal length of the third lens 13, f4 is the focal length of the fourth lens 14, f56 is the focal length of the cemented lens composed of the fifth lens 31 and the sixth lens 3, f7 is the focal length of the seventh lens 33, and f8 is the focal length of the eighth lens 34.

[0165] Figure 8 is Figure 7 the spherical aberration diagram of the lens in Figure 8Among them, the vertical coordinate represents the normalized pupil coordinate, and the horizontal coordinate represents the aberration in the axial direction, with the unit of millimeters. In Figure 8 Among them, the three curves respectively correspond to the axial aberration curves of light with wavelengths of 625 nm, 550 nm, and 455 nm after passing through the lens 100 of this embodiment. From Figure 8 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0166] Figure 9 is Figure 7 the astigmatism field curvature diagram of the lens in Figure 10 is Figure 7 the distortion diagram of the lens in Figure 9 Among them, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 10 Among them, the solid line represents the distortion value of light with a central wavelength of 550 nm after passing through the lens 100 of this embodiment. Combining Figure 9 and Figure 10 it can be known that the lens 100 provided in this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0167] Figure 11 is the structural schematic diagram of the third projection device provided in Embodiment 3 of the present application.

[0168] Combining Figure 11 it can be known that the projection device 400 provided in Embodiment 3 may include a modulation unit 200, a cover glass 300, and a lens 100. Among them, the lens 100 includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. Along the direction from the image side to the object side, the second lens group 30 is disposed between the diaphragm 20 and the modulation unit 200, and the cover glass 300 is disposed between the modulation unit 200 and the lens 100. The number of cover glasses 300 is three, and the three cover glasses 300 are arranged at intervals along the direction from the object side to the image side.

[0169] Combining Figure 11 it can be known that the first lens group 10 may include a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the diaphragm 20. Among them, the first lens 11 has a positive optical power, and the focal length f1 of the first lens 11 = 33.76. The second lens 12 has a negative optical power, and the focal length f2 of the second lens 12 = -16.56. The third lens 13 has a negative optical power, and the focal length f3 of the third lens 13 = -39.08. The fourth lens 14 has a positive optical power, and the focal length f4 of the fourth lens 14 = 43.78.

[0170] Combined Figure 11 It can be seen that the second lens group 30 may include a fifth lens 31, a sixth lens 32, a seventh lens 33, and an eighth lens 34 arranged in sequence from the image side to the object side. The fifth lens 31 is closest to the aperture 20. The fifth lens 31 and the sixth lens 32 form a cemented lens. The eighth lens 34 is closest to the modulation unit 200. Among them, the fifth lens 31 has a negative optical power, the sixth lens 32 has a positive optical power, the cemented lens formed by the fifth lens 31 and the sixth lens 32 has a positive optical power, and the focal length f56 of the cemented lens is 3992.74. The seventh lens 33 has a positive optical power, and the focal length f7 of the seventh lens 33 is 91.10. The eighth lens 34 has a positive optical power, and the focal length f8 of the eighth lens 34 is 35.08.

[0171] The lens closest to the image side in the lens 100 is the first lens 11. The radius of curvature of the image side surface of the first lens 11 is 32.35 mm, which is greater than 26 mm and less than 70 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 100 is 2.267, which is greater than 2 and less than 5, meeting the requirements. The focal length EFL1 of the first lens group 10 is -55.992 mm, which is greater than -58 mm and less than -40 mm, meeting the requirements.

[0172] The lens closest to the object side in the lens 100 is the eighth lens 34. The radius of curvature of the object side surface of the eighth lens 34 is -70.02 mm, which is greater than -140 mm and less than -50 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 34 to the focal length EFL of the lens 100 is -4.908, which is greater than -10 and less than -3, meeting the requirements. The focal length EFL2 of the second lens group 30 is 22.981 mm, which is greater than 19 mm and less than 25 mm, meeting the requirements.

[0173] Along the direction from the image side to the object side, the distance between the object side surface of the eighth lens 34 and the modulation unit 200 is 30.83 mm, that is, the back focal length BFL of the lens 100 is 30.83 mm, which is greater than 28 mm and less than 33 mm, meeting the requirements.

[0174] The focal length EFL of the lens 100 is 14.266 mm, which is greater than 13.5 mm and less than 14.5 mm, meeting the requirements.

[0175] Table 5 shows the optical parameters of each optical element in the third projection device 400 provided in the third embodiment of the present application.

[0176]

[0177]

[0178] Among them, S1 is the image side of the first lens 11, S2 is the object side of the first lens 11, S3 is the image side of the second lens 12, S4 is the object side of the second lens 12, S5 is the image side of the third lens 13, S6 is the object side of the third lens 13, S7 is the image side of the fourth lens 14, S8 is the object side of the fourth lens 14, S9 is the aperture stop 20, S10 is the image side of the fifth lens 31, S11 is the cemented surface of the fifth lens 31 and the sixth lens 32, S12 is the object side of the sixth lens 32, S13 is the image side of the seventh lens 33, S14 is the object side of the seventh lens 33, S15 is the image side of the eighth lens 34, S16 is the object side of the eighth lens 34, S17 is the image side of the first cover glass 300 close to the lens 100, S18 is the object side of the first cover glass 300 close to the lens 100, S19 is the image side of the second cover glass 300 close to the lens 100, S20 is the object side of the second cover glass 300 close to the lens 100, S21 is the image side of the third cover glass 300 close to the lens 100, S22 is the object side of the third cover glass 300 close to the lens 100, S23 is the modulation unit 200, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0179] Among them, R is the radius of curvature of the optical element (such as a lens or the cover glass 300, etc.) at the corresponding position on the optical axis, TH is the surface thickness of the optical element in the direction of the optical axis, Nd is the refractive index of the d-line irradiating each optical element, and Vd is the Abbe number of the optical element.

[0180] Table 6 shows Figure 11 the optical parameters of the lens 100 in

[0181] f1 (mm) 33.758 R1 / EFL 2.267 f2 (mm) -16.563 R2 / EFL -4.908 f3 (mm) -39.081 EFL1 -55.992 f4 (mm) 43.780 EFL2 22.981 f56 (mm) 3992.139 EFL (mm) 14.266 f7 (mm) 91.101 Fno 1.898 f8 (mm) 35.081 BFL (mm) 30.829

[0182] Among them, EFL is the focal length of the lens 100, EFL1 is the focal length of the first lens group 10, EFL2 is the focal length of the second lens group 30, Fno is the aperture of the lens 100, BFL is the back focal length of the lens 100, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 100, f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f3 is the focal length of the third lens 13, f4 is the focal length of the fourth lens 14, f56 is the focal length of the cemented lens composed of the fifth lens 31 and the sixth lens 3, f7 is the focal length of the seventh lens 33, and f8 is the focal length of the eighth lens 34.

[0183] Figure 12 is Figure 11 the spherical aberration diagram of the lens in Figure 12Among them, the vertical coordinate represents the normalized pupil coordinate, and the horizontal coordinate represents the aberration in the axial direction, with the unit of millimeter. In Figure 12 Among them, the three curves respectively correspond to the axial aberration curves of the light with a wavelength of 625 nm, the light with a wavelength of 550 nm, and the light with a wavelength of 455 nm after passing through the lens 100 of this embodiment. From Figure 12 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0184] Figure 13 For Figure 11 the astigmatism field curvature diagram of the lens in Figure 14 For Figure 11 the distortion diagram of the lens in Figure 13 Among them, S represents the field curvature value of the light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of the light with a wavelength of 550 nm in the sagittal image plane. In Figure 14 Among them, the solid line represents the distortion value of the light with a central wavelength of 550 nm after passing through the lens 100 of this embodiment. Combining Figure 13 and Figure 14 it can be known that the lens 100 provided by this embodiment controls the field curvature and distortion within the corresponding ranges, and can meet the use requirements.

[0185] Figure 15 is the structural schematic diagram of the fourth projection device provided by the fourth embodiment of the present application.

[0186] Combining Figure 15 it can be known that the projection device 400 provided by the fourth embodiment may include a modulation unit 200, a cover glass 300, and a lens 100. Among them, the lens 100 includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. Along the direction from the image side to the object side, the second lens group 30 is arranged between the diaphragm 20 and the modulation unit 200, and the cover glass 300 is arranged between the modulation unit 200 and the lens 100. The number of the cover glasses 300 is three, and the three cover glasses 300 are arranged at intervals along the direction from the object side to the image side.

[0187] Combining Figure 15 it can be known that the first lens group 10 may include a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the diaphragm 20. Among them, the first lens 11 has a positive optical power, and the focal length f1 of the first lens 11 = 33.05. The second lens 12 has a negative optical power, and the focal length f2 of the second lens 12 = -14.19. The third lens 13 has a negative optical power, and the focal length f3 of the third lens 13 = -73.9. The fourth lens 14 has a positive optical power, and the focal length f4 of the fourth lens 14 = 80.54.

[0188] CombiningFigure 15 It can be known that the second lens group 30 may include a fifth lens 31, a sixth lens 32, a seventh lens 33, and an eighth lens 34 arranged in sequence from the image side to the object side. The fifth lens 31 is closest to the aperture stop 20. The fifth lens 31 and the sixth lens 32 form a cemented lens. The eighth lens 34 is closest to the modulation unit 200. Among them, the fifth lens 31 has a negative optical power, the sixth lens 32 has a positive optical power, the cemented lens formed by the fifth lens 31 and the sixth lens 32 has a positive optical power, and the focal length f56 of the cemented lens is 263.74. The seventh lens 33 has a positive optical power, and the focal length f7 of the seventh lens 33 is 101.32. The eighth lens 34 has a positive optical power, and the focal length f8 of the eighth lens 34 is 35.18.

[0189] The lens closest to the image side in the lens 100 is the first lens 11. The radius of curvature of the image side surface of the first lens 11 is 32.67 mm, which is greater than 26 mm and less than 70 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 100 is 2.317, which is greater than 2 and less than 5, meeting the requirements. The focal length EFL1 of the first lens group 10 is -45.742 mm, which is greater than -58 mm and less than -40 mm, meeting the requirements.

[0190] The lens closest to the object side in the lens 100 is the eighth lens 34. The radius of curvature of the object side surface of the eighth lens 34 is -70.84 mm, which is greater than -140 mm and less than -50 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 34 to the focal length EFL of the lens 100 is -5.023, which is greater than -10 and less than -3, meeting the requirements. The focal length EFL2 of the second lens group 30 is 23.880 mm, which is greater than 19 mm and less than 25 mm, meeting the requirements.

[0191] In the direction from the image side to the object side, the distance between the object side surface of the eighth lens 34 and the modulation unit 200 is 30.81 mm, that is, the back focal length BFL of the lens 100 is 30.81 mm, which is greater than 28 mm and less than 33 mm, meeting the requirements.

[0192] The focal length EFL of the lens 100 is 14.102 mm, which is greater than 13.5 mm and less than 14.5 mm, meeting the requirements.

[0193] Table 7 shows the optical parameters of each optical element in the fourth projection device 400 provided in the fourth embodiment of the present application.

[0194]

[0195]

[0196] Among them, S1 is the image side of the first lens 11, S2 is the object side of the first lens 11, S3 is the image side of the second lens 12, S4 is the object side of the second lens 12, S5 is the image side of the third lens 13, S6 is the object side of the third lens 13, S7 is the image side of the fourth lens 14, S8 is the object side of the fourth lens 14, S9 is the aperture stop 20, S10 is the image side of the fifth lens 31, S11 is the cemented surface of the fifth lens 31 and the sixth lens 32, S12 is the object side of the sixth lens 32, S13 is the image side of the seventh lens 33, S14 is the object side of the seventh lens 33, S15 is the image side of the eighth lens 34, S16 is the object side of the eighth lens 34, S17 is the image side of the first cover glass 300 close to the lens 100, S18 is the object side of the first cover glass 300 close to the lens 100, S19 is the image side of the second cover glass 300 close to the lens 100, S20 is the object side of the second cover glass 300 close to the lens 100, S21 is the image side of the third cover glass 300 close to the lens 100, S22 is the object side of the third cover glass 300 close to the lens 100, S23 is the modulation unit 200, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0197] Among them, R is the radius of curvature of the optical element (such as a lens or the cover glass 300, etc.) at the corresponding position on the optical axis, TH is the surface thickness of the optical element in the direction of the optical axis, Nd is the refractive index of the d-line irradiated to each optical element, and Vd is the Abbe number of the optical element.

[0198] Table 8 shows Figure 15 the optical parameters of the lens 100 in

[0199] f1 (mm) 33.049 R1 / EFL 2.317 f2 (mm) -14.191 R2 / EFL -5.023 f3 (mm) -73.900 EFL1 -45.742 f4 (mm) 80.545 EFL2 23.880 f56 (mm) 263.742 EFL (mm) 14.102 f7 (mm) 101.322 Fno 2.01 f8 (mm) 35.176 BFL (mm) 30.809

[0200] Among them, EFL is the focal length of the lens 100, EFL1 is the focal length of the first lens group 10, EFL2 is the focal length of the second lens group 30, Fno is the aperture of the lens 100, BFL is the back focal length of the lens 100, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 100, f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f3 is the focal length of the third lens 13, f4 is the focal length of the fourth lens 14, f56 is the focal length of the cemented lens composed of the fifth lens 31 and the sixth lens 3, f7 is the focal length of the seventh lens 33, and f8 is the focal length of the eighth lens 34.

[0201] Figure 16 is Figure 15 the spherical aberration diagram of the lens in Figure 16Among them, the vertical coordinate represents the normalized pupil coordinate, and the horizontal coordinate represents the aberration in the axial direction, with the unit of millimeter. In Figure 16 Among them, the three curves respectively correspond to the axial aberration curves of the light with a wavelength of 625 nm, the light with a wavelength of 550 nm, and the light with a wavelength of 455 nm after passing through the lens 100 of this embodiment. From Figure 16 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0202] Figure 17 is Figure 15 the astigmatism field curvature diagram of the lens in Figure 18 is Figure 15 the distortion diagram of the lens in Figure 17 Among them, S represents the field curvature value of the light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of the light with a wavelength of 550 nm in the sagittal image plane. In Figure 18 Among them, the solid line represents the distortion value of the light with a central wavelength of 550 nm after passing through the lens 100 of this embodiment. Combining Figure 17 and Figure 18 it can be known that the lens 100 provided by this embodiment controls the field curvature and distortion within the corresponding ranges, and can meet the usage requirements.

[0203] Figure 19 is the structural schematic diagram of the fifth projection device provided in the fifth embodiment of the present application.

[0204] Combining Figure 19 it can be known that the projection device 400 provided in the fifth embodiment may include a modulation unit 200, a cover glass 300, and a lens 100. Among them, the lens 100 includes a first lens group 10, a diaphragm 20, and a second lens group 30 arranged from the image side to the object side. Along the direction from the image side to the object side, the second lens group 30 is disposed between the diaphragm 20 and the modulation unit 200, and the cover glass 300 is disposed between the modulation unit 200 and the lens 100. The number of the cover glasses 300 is three.

[0205] Combining Figure 19 it can be known that the first lens group 10 may include a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the fourth lens 14 is closest to the diaphragm 20. Among them, the first lens 11 has a positive optical power, and the focal length f1 of the first lens 11 is 33.05. The second lens 12 has a negative optical power, and the focal length f2 of the second lens 12 is -15.41. The third lens 13 has a negative optical power, and the focal length f3 of the third lens 13 is -33.46. The fourth lens 14 has a positive optical power, and the focal length f4 of the fourth lens 14 is 44.42.

[0206] Combining Figure 19It can be known that the second lens group 30 may include a fifth lens 31, a sixth lens 32, a seventh lens 33, and an eighth lens 34 arranged in sequence from the image side to the object side. The fifth lens 31 is closest to the aperture stop 20. The fifth lens 31 and the sixth lens 32 form a cemented lens. The eighth lens 34 is closest to the modulation unit 200. Among them, the fifth lens 31 has a negative optical power, the sixth lens 32 has a positive optical power, the cemented lens formed by the fifth lens 31 and the sixth lens 32 has a positive optical power, and the focal length f56 of the cemented lens is 354.70. The seventh lens 33 has a positive optical power, and the focal length f7 of the seventh lens 33 is 101.32. The eighth lens 34 has a positive optical power, and the focal length f8 of the eighth lens 34 is 35.18.

[0207] The lens closest to the image side in the lens 100 is the first lens 11. The radius of curvature of the image side surface of the first lens 11 is 32.67 mm, which is greater than 26 mm and less than 70 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 100 is 2.317, which is greater than 2 and less than 5, meeting the requirements. The focal length EFL1 of the first lens group 10 is -48.652 mm, which is greater than -58 mm and less than -40 mm, meeting the requirements.

[0208] The lens closest to the object side in the lens 100 is the eighth lens 34. The radius of curvature of the object side surface of the eighth lens 34 is -70.84 mm, which is greater than -140 mm and less than -50 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the eighth lens 34 to the focal length EFL of the lens 100 is -5.023, which is greater than -10 and less than -3, meeting the requirements. The focal length EFL2 of the second lens group 30 is 23.122 mm, which is greater than 19 mm and less than 25 mm, meeting the requirements.

[0209] In the direction from the image side to the object side, the distance between the object side surface of the eighth lens 34 and the modulation unit 200 is 30.81 mm, that is, the back focal length BFL of the lens 100 is 30.81 mm, which is greater than 28 mm and less than 33 mm, meeting the requirements.

[0210] The focal length EFL of the lens 100 is 14.103 mm, which is greater than 13.5 mm and less than 14.5 mm, meeting the requirements.

[0211] Table 9 shows the optical parameters of each optical element in the fifth projection device 400 provided in the fifth embodiment of the present application.

[0212]

[0213]

[0214] Among them, S1 is the image side of the first lens 11, S2 is the object side of the first lens 11, S3 is the image side of the second lens 12, S4 is the object side of the second lens 12, S5 is the image side of the third lens 13, S6 is the object side of the third lens 13, S7 is the image side of the fourth lens 14, S8 is the object side of the fourth lens 14, S9 is the aperture stop 20, S10 is the image side of the fifth lens 31, S11 is the cemented surface of the fifth lens 31 and the sixth lens 32, S12 is the object side of the sixth lens 32, S13 is the image side of the seventh lens 33, S14 is the object side of the seventh lens 33, S15 is the image side of the eighth lens 34, S16 is the object side of the eighth lens 34, S17 is the image side of the first cover glass 300 close to the lens 100, S18 is the object side of the first cover glass 300 close to the lens 100, S19 is the image side of the second cover glass 300 close to the lens 100, S20 is the object side of the second cover glass 300 close to the lens 100, S21 is the image side of the third cover glass 300 close to the lens 100, S22 is the object side of the third cover glass 300 close to the lens 100, S23 is the modulation unit 200, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0215] Among them, R is the radius of curvature of the optical element (such as a lens or the cover glass 300, etc.) at the corresponding position on the optical axis, TH is the surface thickness of the optical element in the direction of the optical axis, Nd is the refractive index of the d-line irradiated to each optical element, and Vd is the Abbe number of the optical element.

[0216] Table 10 shows Figure 19 the optical parameters of the lens 100 in

[0217] f1 (mm) 33.049 R1 / EFL 2.317 f2 (mm) -15.409 R2 / EFL -5.023 f3 (mm) -33.464 EFL1 -48.652 f4 (mm) 44.419 EFL2 23.122 f56 (mm) 354.703 EFL (mm) 14.103 f7 (mm) 101.322 Fno 1.936 f8 (mm) 35.176 BFL (mm) 30.809

[0218] Among them, EFL is the focal length of the lens 100, EFL1 is the focal length of the first lens group 10, EFL2 is the focal length of the second lens group 30, Fno is the aperture of the lens 100, BFL is the back focal length of the lens 100, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 100, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 100, f1 is the focal length of the first lens 11, f2 is the focal length of the second lens 12, f3 is the focal length of the third lens 13, f4 is the focal length of the fourth lens 14, f56 is the focal length of the cemented lens composed of the fifth lens 31 and the sixth lens 3, f7 is the focal length of the seventh lens 33, and f8 is the focal length of the eighth lens 34.

[0219] Figure 20 is Figure 19 the spherical aberration diagram of the lens in Figure 20Among them, the vertical coordinate represents the normalized pupil coordinate, and the horizontal coordinate represents the aberration in the axial direction, with the unit of millimeters. In Figure 20 Among them, 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 this embodiment. From Figure 20 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0220] Figure 21 is Figure 19 the astigmatism field curvature diagram of the lens in Figure 22 is Figure 19 the distortion diagram of the lens in Figure 21 Among them, S represents the field curvature value of light with a wavelength of 550 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 550 nm in the sagittal image plane. In Figure 22 Among them, the solid line represents the distortion value of light with a central wavelength of 550 nm after passing through the lens 100 of this embodiment. Combining Figure 21 and Figure 22 it can be known that the lens 100 provided in this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0221] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, or an indirect connection through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0222] The device or element referred to in the embodiments of the present application or implied must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "a plurality" is two or more, unless otherwise precisely and specifically defined.

[0223] In the description, claims, and the above-mentioned drawings of the embodiments of the present application, terms such as "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0224] The term "a plurality" as used herein refers to two or more. The term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after; in a formula, the character " / " represents a "division" relationship between the associated objects before and after.

[0225] It can be understood that in the embodiments of the present application, the various numerical numbers involved are only for the convenience of description and are not used to limit the scope of the embodiments of the present application.

[0226] It can be understood that in the embodiments of the present application, the magnitude of the serial numbers of the above processes does not mean the order of execution, and the order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

Claims

1. A lens, characterized in that, it 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 comprises at least four lenses. Along the direction from the image side to the object side, the first lens closest to the image side in the first lens group has a positive focal power, the second lens has a negative focal power, the third lens has a negative focal power, and the fourth lens has a positive focal power; the second lens group comprises at least four lenses. Along the direction from the image side to the object side, the first lens closest to the diaphragm 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.

2. The lens according to claim 1, characterized in that, the lens satisfies the relation: 13.5mm ≤ EFL ≤ 14.5mm, where EFL is the focal length of the lens.

3. The lens according to claim 1 or 2, characterized in that, the lens satisfies the relation: 115mm ≤ L ≤ 150mm. Along the direction from the image side to the object side, L refers to the distance between the lens closest to the image side in the lens and the image.

4. The lens according to any one of claims 1 to 3, characterized in that, the first lens group satisfies the relation: -58mm ≤ EFL1 ≤ -40mm, where EFL1 refers to the focal length of the first lens group.

5. The lens according to any one of claims 1 to 4, characterized in that, the lens satisfies the relation: 2 ≤ R1 / EFL ≤ 5, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens, and EFL is the focal length of the lens.

6. The lens according to any one of claims 1 to 5, characterized in that, the lens satisfies the relation: 26mm ≤ R1 ≤ 70mm, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens.

7. The lens according to any one of claims 1 to 6, characterized in that, the second lens group satisfies the relation: 19mm ≤ EFL2 ≤ 25mm, where EFL2 refers to the focal length of the second lens group.

8. The lens according to any one of claims 1 to 7, characterized in that, the lens satisfies the relation: -10 ≤ R2 / EFL ≤ -3, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens, and EFL is the focal length of the lens.

9. The lens according to any one of claims 1 to 8, characterized in that, the lens satisfies the relation: -140mm ≤ R2 ≤ -50mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens.

10. The lens according to any one of claims 1 to 9, characterized in that, the lens satisfies the relation: 28mm ≤ BFL ≤ 33mm, where BFL is the back focal length of the lens.

11. The lens according to any one of claims 1 to 10, characterized in that, The first lens group includes a first lens with a positive focal power, a second lens with a negative focal power, a third lens with a negative focal power, and a fourth lens with a positive focal power arranged from the image side to the object side. The first lens is closest to the image side, and the fourth lens is closest to the diaphragm. The second lens group includes a fifth lens with a negative focal power, a sixth lens with a positive focal power, a seventh lens with a positive focal power, and an eighth lens with a positive focal power arranged from the image side to the object side. The fifth lens is closest to the diaphragm, and the eighth lens is closest to the object side.

12. A projection device Characterized in that It includes a display unit and a lens as described in any one of claims 1 to 11, and 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.

13. A display device Characterized in that It includes an imaging module and a projection device as described in claim 12; The imaging module generates a target image based on the image light emitted by the projection device.

14. A vehicle Characterized in that It includes a display device as described in claim 13.

15. The vehicle according to claim 14 Characterized in that The display device is installed in the instrument panel of the vehicle.

16. The vehicle according to claim 14 or 15, wherein the vehicle further includes a windshield, the image light emitted by the display device is incident on the windshield, and the windshield reflects the image light to the human eye.

Images