Lens, projection device, vehicle lamp device and vehicle

Abstract

The embodiment of the invention provides a lens, a projection device, a vehicle lamp device and a vehicle, and belongs to the technical field of optics. The lens comprises at least five lenses arranged from an image side to an object side. The image side face of the lens closest to the image side in the lens is a concave face, the number of the lenses with the positive focal power in the lens is at least three, and the number of the lenses with the negative focal power in the lens is at least one. Wherein when the number of the lens with the negative focal power is one, the lens with the negative focal power is arranged between the lens, closest to the image side, in the lenses and the lens, closest to the object side, in the lenses. According to the lens provided by the embodiment of the invention, a relatively large field angle can be realized under the condition that Fno is less than or equal to 1.0, so that the lens can have the characteristics of a large aperture and a large field angle at the same time.

Description

Technical Field

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

[0002] With the development of intelligent vehicle technologies, vehicle headlamps are required to have traditional lighting functions and be able to project patterns to meet the increasing demands in aspects such as welcoming guests, information interaction, and autonomous driving. Therefore, in order to meet more and more requirements, the optical requirements for vehicle headlamps capable of projecting patterns will become increasingly strict. For example, it is required that the vehicle headlamp has a relatively wide field of view (FOV) that can be projected. The field of view can be one of the important indicators reflecting the amount of projected information. The larger the field of view, the greater the amount of information that can be projected. However, the lenses applied to vehicle headlamps cannot simultaneously have a large aperture and a large field of view. Summary of the Invention

[0003] The embodiments of the present application provide a lens, a projection device, a vehicle headlamp device, and a vehicle, which can enable the lens to simultaneously have a large aperture and a large field of view.

[0004] In a first aspect of the present application, a lens is provided, including at least five lenses arranged from the image side to the object side. The image side surface of the lens closest to the image side in the lens is a concave surface. The number of lenses with positive refractive power in the lens is at least three, and the number of lenses with negative refractive power in the lens is at least one. Among them, when the number of lenses with negative refractive power is one, the lens with negative refractive power is arranged between the lens closest to the image side and the lens closest to the object side in the lens.

[0005] The lens provided by the embodiments of the present application is composed of at least five lenses. At least three of the lenses have positive refractive power, at least one lens in the lens has negative refractive power, and the image side surface of the lens closest to the image side in the lens is a concave surface. It can achieve a large field of view under the condition that Fno is less than or equal to 1.0. Thus, the lens can simultaneously have the characteristics of a large aperture and a large field of view, and further can meet the projection requirements. In addition, on the premise of achieving a large aperture and a large field of view, it is also possible to ensure that the back focal length of the lens is long enough, which is beneficial to the setting of the rear optical path.

[0006] Among them, when the number of lenses with negative refractive power is one, the lens with negative refractive power is arranged between the lens closest to the image side and the lens closest to the object side in the lens, which can ensure that the lens simultaneously has the characteristics of a large aperture and a large field of view. In addition, when the number of lenses with negative refractive power is at least two, and the lens closest to the object side and / or the image side in the lens has negative refractive power, it can also make the lens simultaneously have the characteristics of a large aperture and a large field of view.

[0007] In a possible implementation, the lens satisfies the relation: 0.8 < BFL / EFL < 0.9, where BFL is the back focal length of the lens and EFL is the focal length of the lens.

[0008] After the lens provided by the embodiment of the present application satisfies the relation: 0.8 < BFL / EFL < 0.9, it can avoid the optical path of the lens from being too long or too short, which is beneficial to the design and the setting of the back-end optical path. In addition, it can also ensure that the lens has the characteristics of a large aperture and a large field of view at the same time.

[0009] In a possible implementation, the lens satisfies the relation: 33mm < EFL < 38mm, where EFL is the focal length of the lens.

[0010] The focal length of the lens provided by the embodiment of the present application is greater than 33mm and less than 38mm. On the premise of realizing a large aperture, it can realize a field of view angle greater than 20°X10°, where 20° refers to the field of view angle of the lens in the horizontal direction, and 10° refers to the field of view angle of the lens in the vertical direction.

[0011] In a possible implementation, the lens satisfies the relation: -4 < R1 / EFL < -2, 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.

[0012] By satisfying the relation: -4 < R1 / EFL < -2, the lens provided by the embodiment of the present application can reduce the manufacturing difficulty of the lens closest to the image side in the lens, improve the yield rate, and is beneficial to improving the economy while realizing a large aperture and a large field of view at the same time. In addition, it can also facilitate the correction of aberrations. In addition, it can also avoid the image side surface of the lens closest to the image side from being too prominent or too flat. Among them, the image side surface of the lens closest to the image side being too prominent may cause interference between this lens and the remaining components, and the image side surface of the lens closest to the image side being too flat will affect the shape of the vehicle lamp.

[0013] In a possible implementation, the lens satisfies the relation: -152mm < R1 < -99mm, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens.

[0014] By satisfying the relation: -152mm < R1 < -99mm, the lens provided by the embodiment of the present application can also reduce the manufacturing difficulty of the lens closest to the image side in the lens, improve the yield rate, and is beneficial to improving the economy while realizing a large aperture and a large field of view at the same time. In addition, it can also facilitate the correction of aberrations. In addition, it can also avoid the image side surface of the lens closest to the image side from being too prominent or too flat, and effectively balance the optical performance of the lens and the shape of the vehicle lamp.

[0015] In a possible implementation, the lens satisfies the relationship: -10 < R2 / EFL < 10, 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.

[0016] The lens provided by the embodiment of the present application can, by satisfying the relationship: -10 < R2 / EFL < 10, reduce the manufacturing difficulty of the lens closest to the object side in the lens and improve the yield rate on the premise of simultaneously achieving a large aperture and a large field of view angle, which is beneficial to improving the economy. In addition, it can also prevent the object side surface of the lens closest to the object side from being too protruding or too concave. Among them, if the object side surface of the lens closest to the object side is too protruding, it will interfere with the remaining optical elements, or compress the optical space between the lens and the projection chip, or cause damage to the lens close to the object side. If the object side surface of the lens closest to the object side is too concave, it will be unfavorable for aberration correction.

[0017] In a possible implementation, the lens satisfies the relationship: -380 mm < R2 < 380 mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens.

[0018] The lens provided by the embodiment of the present application satisfies the relationship: -380 mm < R2 < 380 mm, and can also reduce the manufacturing difficulty of the lens closest to the object side in the lens and improve the yield rate on the premise of simultaneously achieving a large aperture and a large field of view angle, which is beneficial to improving the economy. In addition, it can also prevent the object side surface of the lens closest to the object side from being too protruding or too concave, effectively balancing the optical performance of the lens and the shape of the vehicle lamp.

[0019] In a possible implementation, the lens closest to the image side in the lens has a positive optical power.

[0020] The lens provided by the embodiment of the present application can, by setting the lens closest to the image side to a lens with a positive optical power, be beneficial to improving the economy of the lens on the premise of simultaneously achieving a large aperture and a large field of view angle.

[0021] In a possible implementation, the lens closest to the object side in the lens has a positive optical power.

[0022] The lens provided by the embodiment of the present application can, by setting the lens closest to the object side to a lens with a positive optical power, increase the amount of light entering the lens to improve the optical performance. In addition, it can also improve the economy of the lens.

[0023] The second projection device according to the first aspect of the present application includes a display unit and a lens according to any item of the first aspect, and the display unit is configured to emit imaging light to the lens.

[0024] In a possible implementation, the display unit includes a light source unit and a modulation unit. Among them, the modulation unit is configured to modulate the light beam emitted by the light source unit to generate imaging light and emit the imaging light to the lens.

[0025] In a possible implementation, the display unit further includes a reflection unit, and the reflection unit is configured to reflect the light beam emitted by the light source unit to the modulation unit.

[0026] A vehicle headlight device according to a third aspect of the present application includes a housing and a projection device according to any one of the second aspects, and at least a part of the projection device is disposed inside the housing.

[0027] A vehicle according to a fourth aspect of the present application includes the vehicle headlight device according to the third aspect. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a vehicle headlight device provided by an embodiment of the present application;

[0029] Figure 2 It is a schematic structural diagram of a lens provided by an embodiment of the present application;

[0030] Figure 3 It is a schematic structural diagram of a first projection device provided by Embodiment 1 of the present application;

[0031] Figure 4 It is Figure 3 the spherical chromatic aberration diagram of the lens in;

[0032] Figure 5 It is Figure 3 the astigmatism field curvature diagram of the lens in;

[0033] Figure 6 It is Figure 3 the distortion diagram of the lens in;

[0034] Figure 7 It is a schematic structural diagram of a second projection device provided by Embodiment 2 of the present application;

[0035] Figure 8 It is Figure 7 the spherical chromatic aberration diagram of the lens in;

[0036] Figure 9 It is Figure 8 the astigmatism field curvature diagram of the lens in;

[0037] Figure 10 It is Figure 8 the distortion diagram of the lens in;

[0038] Figure 11 It is a schematic structural diagram of a third projection device provided by Embodiment 3 of the present application;

[0039] Figure 12 For Figure 11 the spherical aberration diagram of the lens in

[0040] Figure 13 For Figure 11 the astigmatism field curvature diagram of the lens in

[0041] Figure 14 For Figure 11 the distortion diagram of lens 10 in

[0042] Description of reference numerals:

[0043] 100, vehicle headlamp device;

[0044] 110, housing; 120, projection device;

[0045] 10, lens; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 16, aperture; 17, cover glass;

[0046] 20, display unit; 21, light source unit; 211, light source; 212, collimating unit; 22, modulation unit; 23, reflection unit. Detailed implementation manners

[0047] The terms used in the implementation manners part of this application are only used to explain the specific embodiments of this application, rather than being intended to limit this application.

[0048] For ease of understanding, first, relevant technical terms involved in the embodiments of this application are explained and described.

[0049] Focal length, also known as focal length, is a measure of the aggregation 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.

[0050] 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.

[0051] 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.

[0052] Total length (total track length, abbreviated as TTL) refers to the total length from the vertex of the first lens arranged adjacent to the object side in the lens to the imaging surface of the lens, and is also known as the total optical length.

[0053] 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.

[0054] Optical power characterizes the refractive ability of a lens for incident parallel light beams.

[0055] Positive optical power indicates that the lens has a positive focal length and has the effect of converging light rays.

[0056] Negative optical power indicates that the lens has a negative focal length and has the effect of diverging light rays.

[0057] An aperture is a device used to control the amount of light passing through the lens into the interior of an electronic device. It is usually inside the lens, and the size of the aperture is expressed by the value of F# (F-number).

[0058] The aperture number F# is the relative value obtained by dividing the focal length of the lens by the clear aperture diameter of the lens (the reciprocal of the relative aperture). The smaller the value of the aperture number F#, the more light enters in the same unit time.

[0059] Cover glass (CG) is used to protect the projection chip.

[0060] The modulation unit is used to modulate the light beam emitted by the light source to generate the image light for forming an image.

[0061] Digital micromirror devices (DMD) are used to reflect light rays to form an image.

[0062] Liquid crystal on silicon (LCOS) is used to reflect light rays.

[0063] Axial chromatic aberration, also known as longitudinal chromatic aberration or position chromatic aberration, is that a beam of light 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 positions of the images formed by the lens for lights of different wavelengths are different, so that when finally imaging, the imaging planes of lights of different colors cannot completely coincide, and the polychromatic light spreads to form dispersion.

[0064] Distortion, also known as aberration, is the degree of distortion of the image formed by an optical system for an object relative to the object itself. Distortion is due to the influence of the aperture aberration. The height of the chief ray of different fields of view passing through the optical system and intersecting with the Gaussian image plane is not equal to the ideal image height, and the difference between the two is the distortion. Therefore, distortion only changes the imaging position of off-axis object points on the ideal plane, making the shape of the image distorted, but does not affect the clarity of the image.

[0065] With the development of intelligent vehicle technology, in-vehicle headlights are required to have traditional lighting functions and be able to project patterns to meet the increasing demands in aspects such as welcome, information interaction, and autonomous driving. Therefore, in order to meet more and more requirements, the optical requirements for headlights capable of projecting patterns will become increasingly strict. For example, it is required that the headlights have a relatively wide field of view (FOV) that can be projected. The field of view can be one of the important indicators reflecting the amount of projected information. The larger the field of view, the greater the amount of information that can be projected. However, the lenses applied to vehicle headlights cannot simultaneously have a large aperture and a large field of view. Therefore, how to enable the lens to simultaneously have a large aperture and a large field of view has become an urgent problem to be solved.

[0066] In view of this, the embodiments of the present application provide a lens 10, a projection device 120, a vehicle headlight device 100, and a vehicle. The lens 10 can simultaneously have the characteristics of a large aperture and a large field of view, and can improve the projection range and brightness to meet the usage requirements.

[0067] The vehicle provided by the embodiments of the present application may include, but is not limited to, cars, trucks, motorcycles, buses, ships, airplanes, helicopters, lawn mowers, recreational vehicles, amusement park vehicles, construction equipment, trams, golf carts, trains, or handcarts, etc. Among them, in the embodiments of the present application, a car is taken as an example of the above vehicle for illustration. The vehicle may include a vehicle headlight device 100, which can emit illumination light at night to ensure driving safety.

[0068] The vehicle headlight device 100 provided by the embodiments of the present application may include, but is not limited to, pixel display headlights, near-field welcome headlights, pedestrian or interactive headlights, automotive headlights, etc. For example, in the embodiments of the present application, automotive headlights are taken as an example of the above vehicle headlight device 100 for illustration. The vehicle headlight device 100 can play the roles of projection imaging and display lighting, such as lighting at night.

[0069] Figure 1 It is a schematic structural diagram of a vehicle headlight device provided by an embodiment of the present application. Refer to Figure 1 As shown, the vehicle headlight device 100 may include a housing 110 and a projection device 120. At least a part of the projection device 120 is disposed inside the housing 110. For example, Figure 1 As shown, the projection device 120 is disposed inside the housing 110. Of course, a part of the projection device 120 may also be disposed inside the housing 110, and another part may be disposed outside the housing 110. The projection device 120 is used for projection imaging and display lighting.

[0070] Refer to Figure 1As shown, the projection device 120 may include a display unit 20 and a lens 10. The display unit 20 is configured to emit imaging light towards the lens 10, and the lens 10 may project the imaging light outside the housing 110 to form an image outside the housing 110 or serve as an illumination function.

[0071] See Figure 1 As shown, the display unit 20 includes a light source unit 21 and a modulation unit 22. Among them, the modulation unit 22 is configured to modulate the light beam emitted by the light source unit 21 to generate imaging light and emit the imaging light towards the lens 10.

[0072] Regarding the specific structure of the modulation unit 22, no limitation is imposed here. Exemplarily, the modulation unit 22 may be a projection chip, and the projection chip may modulate the light beam emitted by the light source unit 21 and generate imaging light directed towards the lens 10. Among them, the projection chip may include but is not limited to DMD, LCOS, MEMS, or LCD, etc.

[0073] In some possible implementation manners, continue to refer to Figure 1 As shown, the light source unit 21 may further include a light source 211 and a collimation unit 212. Among them, the collimation unit 212 is configured to collimate the light emitted by the light source 211 and transmit the collimated light beam to a reflection unit 23, and the reflection unit 23 reflects the collimated light beam to the modulation unit 22.

[0074] In some possible implementation manners, continue to refer to Figure 1 As shown, the display unit 20 may further include a reflection unit 23, and the reflection unit 23 is configured to reflect the light beam emitted by the light source unit 21 to the modulation unit 22.

[0075] Regarding the specific structure of the reflection unit 23, no limitation is imposed here. Exemplarily, continue to refer to Figure 1 As shown, the reflection unit 23 may be a curved mirror, and the light emitted by the light source unit 21 is reflected to the modulation unit 22 through the curved surface of the curved mirror.

[0076] It should be noted that in addition to being applied to the projection imaging and display illumination of the vehicle headlight device 100, the projection device 120 provided in the embodiments of the present application can also be applied to devices such as projectors, head-up display devices, and augmented reality (AR) glasses to play a role in projection imaging.

[0077] Next, with reference to the accompanying drawings, the lens 10 provided in the embodiments of the present application will be described.

[0078] Figure 2 It is a schematic structural diagram of a lens provided in an embodiment of the present application.

[0079] The lens 10 provided by the embodiment of the present application includes at least five lenses arranged from the image side to the object side. For example, Figure 2 As shown, the lens 10 may include five lenses arranged in sequence from the image side to the object side. The five lenses are respectively a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15. Of course, the number of lenses may also be more than five. As Figure 2 shown, the image side surface of the lens closest to the image side in the lens 10 is a concave surface, that is, the image side surface of the first lens 11 is a concave surface. The number of lenses with positive refractive power in the lens 10 is at least three, and the number of lenses with negative refractive power in the lens 10 is at least one. For example, Figure 2 As shown, four of the five lenses have positive refractive power and the other one has negative refractive power. Of course, the number of lenses with positive refractive power among the five lenses may also be three. In addition, the number of lenses with negative refractive power among the five lenses may also be two. Among them, when the number of lenses with negative refractive power is one, the lens with negative refractive power is disposed between the lens closest to the image side in the lens 10 and the lens closest to the object side in the lens 10. For example, Figure 2 As shown, the lens 10 may include a first lens 11 with positive refractive power, a second lens 12 with positive refractive power, a third lens 13 with negative refractive power, a fourth lens 14 with positive refractive power, and a fifth lens 15 with positive refractive power arranged from the image side to the object side. The first lens 11 is closest to the image side, and the fifth lens 15 is closest to the object side. When the number of lenses with negative refractive power is more than one, there is no limitation on the position of the lenses with negative refractive power.

[0080] The lens 10 is composed of at least five lenses. At least three of the lenses have positive refractive power, and at least one lens in the lens 10 has negative refractive power. The image side surface of the lens closest to the image side in the lens 10 is a concave surface, and a large field of view angle can be achieved under the condition that Fno is less than or equal to 1.0. Thus, the lens 10 can simultaneously have the characteristics of a large aperture and a large field of view angle, and further can meet the projection requirements. In addition, on the premise of achieving a large aperture and a large field of view angle, it can also ensure that the back focal length of the lens 10 is long enough, which is beneficial to the setting of the rear optical path.

[0081] Among them, when the number of lenses with negative refractive power is one, the lens with negative refractive power is disposed between the lens closest to the image side in the lens 10 and the lens closest to the object side in the lens 10, which can ensure that the lens 10 simultaneously has the characteristics of a large aperture and a large field of view angle. When the number of lenses with negative refractive power is at least two, the lens closest to the object side and / or the image side in the lens 10 may also have negative refractive power, which can also ensure that the lens 10 simultaneously has the characteristics of a large aperture and a large field of view angle.

[0082] In some possible implementation manners, the lens 10 may further satisfy the relational expression: 0.8 < BFL / EFL < 0.9, where BFL is the back focal length of the lens 10, and EFL is the focal length of the lens 10.

[0083] Correspondingly, after the lens 10 satisfies the relational expression: 0.8 < BFL / EFL < 0.9, it is possible to avoid the optical path of the lens 10 from being too long or too short, which is beneficial to the design and the setting of the back-end optical path. In addition, it can also ensure that the lens 10 has the characteristics of a large aperture and a large field of view angle at the same time. There is no limitation on the specific ratio of BFL / EFL here. For example, it may include but is not limited to 0.81, 0.82, 0.83, 0.84, 0.85, 0.8591, 0.86, 0.87, 0.88, or 0.89, etc.

[0084] In some possible implementation manners, the lens 10 may further satisfy the relational expression: 33 mm < EFL < 38 mm, where EFL is the focal length of the lens 10.

[0085] Correspondingly, when the focal length of the lens 10 is greater than 33 mm and less than 38 mm, it is possible to achieve a field of view angle greater than 20°×10° on the premise of realizing a large aperture, where 20° refers to the field of view angle of the lens 10 in the horizontal direction, and 10° refers to the field of view angle of the lens 10 in the vertical direction.

[0086] There is no limitation on the specific value of the focal length of the lens 10 here. For example, it may include but is not limited to 33.5 mm, 33.88 mm, 33.9 mm, 34 mm, 34.5 mm, 35 mm, 35.3 mm, 36 mm, 37 mm, or 37.5 mm, etc.

[0087] In some possible implementation manners, the lens 10 may further satisfy the relational expression: -4 < R1 / EFL < -2, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens 10, and EFL is the focal length of the lens 10.

[0088] Correspondingly, when the lens 10 satisfies the relational expression: -4 < R1 / EFL < -2, it is possible to reduce the manufacturing difficulty of the lens closest to the image side in the lens 10, improve the yield rate, and be beneficial to improving the economy on the premise of realizing a large aperture and a large field of view angle at the same time. In addition, it can also facilitate the correction of aberrations. Moreover, it can avoid the image side surface of the lens closest to the image side in the lens 10 from being too prominent or too flat. Among them, the too prominent image side surface of the lens closest to the image side may cause interference between this lens and the remaining components, and the too flat image side surface of the lens closest to the image side will affect the shape of the vehicle lamp. There is no limitation on the specific ratio of R1 / EFL here. For example, it may include but is not limited to -2.1, -2.5, -3, -3.5, -3.6, -3.8, -3.9, or -3.985, etc.

[0089] In some possible implementation manners, the lens 10 may further satisfy the relational expression: -152 mm < R1 < -99 mm, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens 10.

[0090] Correspondingly, the lens 10 may also satisfy the relational expression: -152 mm < R1 < -99 mm. Also, on the premise of simultaneously achieving a large aperture and a large field of view angle, the manufacturing difficulty of the lens closest to the image side in the lens 10 can be reduced, the yield can be improved, which is beneficial to enhancing the economy. In addition, it can facilitate the correction of aberrations. Moreover, it can avoid the image side surface of the lens closest to the image side in the lens 10 from being too protruding or too flat, effectively balancing the optical performance of the lens 10 and the shape of the vehicle lamp.

[0091] There is no limitation on the specific value of R1 here. For example, it may include but is not limited to -99.5 mm, -100 mm, -105 mm, -110 mm, -115 mm, -120 mm, -121 mm, -125 mm, -130 mm, -135 mm, -140 mm, -145 mm, -150 mm, -151 mm or -151.95 mm, etc.

[0092] In some possible implementation manners, the lens 10 may further satisfy the relational expression: -10 < R2 / EFL < 10, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens 10, and EFL is the focal length of the lens 10.

[0093] Correspondingly, when the lens 10 satisfies the relational expression: -10 < R2 / EFL < 10, on the premise of simultaneously achieving a large aperture and a large field of view angle, the manufacturing difficulty of the lens closest to the object side in the lens 10 can be reduced, the yield can be improved, which is beneficial to enhancing the economy. In addition, it can avoid the object side surface of the lens closest to the object side in the lens 10 from being too protruding or too concave. Among them, if the object side surface of the lens closest to the object side is too protruding, it will interfere with the remaining optical elements, or compress the optical space between the lens 10 and the projection chip, or cause damage to the lens close to the object side. If the object side surface of the lens closest to the object side is too concave, it will be unfavorable for aberration correction.

[0094] There is no limitation on the specific ratio of R2 / EFL here. For example, it may include but is not limited to -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 1.85, 1.897, 1.9, 1.95, 2, 2.5, 5.987, 2.6, 3, 3.5, 3.6, 4, 4.5, 5, 5.1, 5.159, 5.19, 5.195, 6, 7, 8, 9, 9.1, 9.22 or 9.984, etc.

[0095] In some possible implementations, the lens 10 may also satisfy the relationship: -380 mm < R2 < 380 mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens 10.

[0096] Correspondingly, the lens 10 satisfies the relationship: -380 mm < R2 < 380 mm. Also, on the premise of simultaneously achieving a large aperture and a large field of view angle, the manufacturing difficulty of the lens closest to the object side in the lens 10 can be reduced, the yield can be improved, which is beneficial to enhancing the economy. In addition, it can also prevent the object side surface of the lens closest to the object side in the lens 10 from being too prominent or too concave, effectively balancing the optical performance of the lens 10 and the shape of the vehicle lamp. There is no limitation on the specific value of R2 here. For example, it may include but is not limited to -375 mm, -370 mm, -350 mm, -300 mm, -250 mm, -200 mm, -150 mm, -100 mm, 0, 10 mm, 50 mm, 73.5 mm, 76.98 mm, 79 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 121 mm, 125 mm, 129 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 181 mm, 182 mm, 183 mm, 184 mm, 184.954 mm, 200 mm, 250 mm, 300 mm, 310 mm, 340 mm, 350 mm, 355 mm, 359 mm, 360 mm, 370 mm or 375 mm, etc. In some possible implementations, the lens closest to the image side in the lens 10 may have a positive optical power. For example Figure 2 as shown, the first lens 11 closest to the image side has a positive optical power. Of course, the first lens 11 may also have a negative optical power.

[0097] Correspondingly, by setting the lens closest to the image side as a lens with a positive optical power, on the premise of simultaneously achieving a large aperture and a large field of view angle, it is beneficial to improve the economy of the lens 10.

[0098] In some possible implementations, the lens closest to the object side in the lens 10 may have a positive optical power. For example Figure 2 as shown, the fifth lens 15 closest to the object side has a positive optical power. Of course, the fifth lens 15 may also have a negative optical power.

[0099] Correspondingly, by setting the lens closest to the object side as a lens with a positive optical power, the light input amount entering the lens 10 can be increased to improve the optical performance. In addition, the economy of the lens 10 can also be improved.

[0100] In some possible implementations, at least one lens may be a spherical mirror. For exampleFigure 2 As shown, all five lenses in the lens 10 can be spherical lenses. Of course, the number of spherical lenses can also be less than five.

[0101] Correspondingly, in the embodiment of the present application, the more spherical lenses the lens 10 adopts, the greater the degree of reducing the processing difficulty of the lens 10, which is beneficial to improving the yield. In addition, the imaging quality can also be improved.

[0102] In some possible implementation manners, as shown in Figure 2 As shown, the lens 10 may further include a diaphragm 16. Among them, the diaphragm 16 may be disposed between two adjacent lenses in the lens 10. For example, Figure 2 As shown, the diaphragm 16 may be disposed between the third lens 13 and the fourth lens 14. Of course, the diaphragm 16 may also be disposed at other positions.

[0103] In some possible implementation manners, as shown in Figure 2 As shown, the lens 10 may further include a cover glass 17. Among them, the cover glass 17 is used to be disposed between the lens closest to the object side in the lens 10 and the modulation unit 22, and the cover glass 17 is used to protect the modulation unit 22.

[0104] In some possible implementation manners, the lens 10 may further include a filter (not shown in the figure) for correcting color deviation. Among them, the filter is used to be disposed between the lens closest to the object side in the lens 10 and the modulation unit 22.

[0105] It should be noted that one of the cover glass 17 and the filter may be provided in the lens 10, or both may exist.

[0106] Next, the structure and performance of the projection device 120 provided in the embodiment of the present application will be described with reference to specific embodiments.

[0107] Figure 3 It is a schematic structural diagram of the first projection device provided in Embodiment 1 of the present application.

[0108] As shown in Figure 3 As shown, the projection device 120 may include a lens 10 and a modulation unit 22. Among them, the lens 10 includes a first lens 11, a second lens 12, a third lens 13, a diaphragm 16, a fourth lens 14, a fifth lens 15, and a cover glass 17 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the image side surface of the first lens 11 is concave. The fifth lens 15 is closest to the object side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, and the projection chip may be a DMD or an LCOS.

[0109] Among them, the first lens 11 has a positive optical power. The ratio of the focal length f1 of the first lens 11 to the focal length EFL of the lens 10 is: |f1 / EFL| = 3.27. The second lens 12 has a positive optical power. The ratio of the focal length f2 of the second lens 12 to the focal length EFL of the lens 10 is: |f2 / EFL| = 2.45. The third lens 13 has a negative optical power. The ratio of the focal length f3 of the third lens 13 to the focal length EFL of the lens 10 is: |f3 / EFL| = 2.11. The fourth lens 14 has a positive optical power. The ratio of the focal length f4 of the fourth lens 14 to the focal length EFL of the lens 10 is: |f4 / EFL| = 1.16. The fifth lens 15 has a positive optical power. The ratio of the focal length f5 of the fifth lens 15 to the focal length EFL of the lens 10 is: |f5 / EFL| = 1.77.

[0110] The lens closest to the image side in the lens 10 is the first lens 11. The radius of curvature R1 of the image side of the first lens 11 is -115 mm, which is greater than -152 mm and less than -99 mm, meeting the requirements. The ratio R1 / EFL of the radius of curvature R1 of the image side of the first lens 11 to the focal length EFL of the lens 10 is -3.25, which is greater than -4 and less than -2, meeting the requirements.

[0111] The lens closest to the object side in the lens 10 is the fifth lens 15. The radius of curvature R2 of the object side of the fifth lens 15 is 194 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side of the fifth lens 15 to the focal length EFL of the lens 10 is 5.44, which is greater than -10 and less than 10, meeting the requirements.

[0112] The ratio BFL / EFL of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10 is 0.851, which is greater than 0.8 and less than 0.9, meeting the requirements.

[0113] The focal length EFL of the lens 10 is 35.75 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0114] Table 1 shows the optical parameters of each optical element in the projection device 120 provided in the first embodiment.

[0115]

[0116]

[0117] 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 aperture stop 16, S8 is the image side of the fourth lens 14, S9 is the object side of the fourth lens 14, S10 is the image side of the fifth lens 15, S11 is the object side of the fifth lens 15, S12 is the image side of the cover glass 17, S13 is the object side of the cover glass 17, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0118] Among them, R is the radius of curvature of the optical element (such as a lens or a glass cover plate, 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.

[0119] Table 2 shows the optical parameters of the lens 10 provided in the first embodiment.

[0120] f1 (mm) 114.810 EFL (mm) 35.75 f2 (mm) 86.018 TTL (mm) 90.79 f3 (mm) -73.838 Fno 1.0 f4 (mm) 40.848 BFL (mm) 29.84 f5 (mm) 62.119 R1 (mm) -115 R2 (mm) 194.44 FOV (°) 22.3

[0121] Among them, EFL is the focal length of the lens 10, FOV is the maximum field of view angle of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 10, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 10, 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, and f5 is the focal length of the fifth lens 15.

[0122] Figure 4 For Figure 3 is the spherical aberration diagram of the lens in Figure 4 In Figure 4 the ordinate represents the normalized pupil coordinate, and the abscissa represents the aberration in the axial direction, with the unit of millimeter. In Figure 4 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and better correction is obtained.

[0123] Figure 5 For Figure 3 is the astigmatism field curvature diagram of the lens in Figure 6 For Figure 3 is the distortion diagram of the lens in Figure 5Among them, S represents the field curvature value of light with a wavelength of 525 nm on the meridional image plane, and T represents the field curvature value of light with a wavelength of 525 nm on the sagittal image plane. In Figure 6 Among them, the solid line represents the distortion value of light with a central wavelength of 525 nm passing through the lens 10 of this embodiment. In this embodiment, combining Figure 5 and Figure 6 it can be known that the lens 10 provided in this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0124] Figure 7 FIG. 10 is a schematic structural diagram of a second projection device provided in Embodiment 2 of the present application.

[0125] Referring to Figure 7 as shown, the projection device 120 may include a lens 10 and a modulation unit 22. Among them, the lens 10 includes a first lens 11, a second lens 12, a third lens 13, a diaphragm 16, a fourth lens 14, a fifth lens 15, and a cover glass 17 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the image side surface of the first lens 11 is a concave surface. The fifth lens 15 is closest to the image side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, and the projection chip may be a DMD or an LCOS.

[0126] Among them, the first lens 11 has a positive optical power, and the ratio of the focal length f1 of the first lens 11 to the focal length EFL of the lens 10: |f1 / EFL| = 3.33. The second lens 12 has a positive optical power, and the ratio of the focal length f2 of the second lens 12 to the focal length EFL of the lens 10: |f2 / EFL| = 2.32. The third lens 13 has a negative optical power, and the ratio of the focal length f3 of the third lens 13 to the focal length EFL of the lens 10: |f3 / EFL| = 2.227. The fourth lens 14 has a positive optical power, and the ratio of the focal length f4 of the fourth lens 14 to the focal length EFL of the lens 10: |f4 / EFL| = 1.188. The fifth lens 15 has a positive optical power, and the ratio of the focal length f5 of the fifth lens 15 to the focal length EFL of the lens 10: |f5 / EFL| = 1.787.

[0127] The lens closest to the image side in the lens 10 is the first lens 11, and the radius of curvature R1 of the image side surface of the first lens 11 = -101.6 mm, which is greater than -152 mm and less than -99 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 10 = -2.8968, which is greater than -4 and less than -2, meeting the requirements.

[0128] The lens closest to the object side in the lens 10 is the fifth lens 15. The radius of curvature R2 of the object side surface of the fifth lens 15 is 210.16 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio R2 / EFL of the radius of curvature R2 of the object side surface of the fifth lens 15 to the focal length EFL of the lens 10 is 5.9917, which is greater than -10 and less than 10, meeting the requirements.

[0129] The ratio BFL / EFL of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10 is 0.8508, which is greater than 0.8 and less than 0.9, meeting the requirements.

[0130] The focal length EFL of the lens 10 is 35.07 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0131] Table 3 shows the optical parameters of each optical element in the projection device 120 provided in the second embodiment.

[0132] Surface number Surface type R (mm) TH (mm) Nd Vd OBJ Spherical surface Infinity 10000 S1 Spherical surface -101.606 9.200 1.91 35.5 S2 Spherical surface -54.499 0.058 S3 Spherical surface 56.168 4.571 2.02 29.1 S4 Spherical surface 161.015 6.237 S5 Spherical surface -33.215 10.350 S6 Spherical surface 64.183 2.645 1.81 22.7 S7 Spherical surface Infinity 0.000 S8 Spherical surface 157.660 21.388 1.73 54.7 S9 Spherical surface -35.774 0.057 S10 Spherical surface 41.934 6.052 1.82 46.6 S11 Spherical surface 210.159 3.102 S12 Spherical surface Infinity 1.265 1.523 58.6 S13 Spherical surface Infinity 25.533 ImgH Spherical surface Infinity -0.052

[0133] Among them, S1 is the image side surface of the first lens 11, S2 is the object side surface of the first lens 11, S3 is the image side surface of the second lens 12, S4 is the object side surface of the second lens 12, S5 is the image side surface of the third lens 13, S6 is the object side surface of the third lens 13, S7 is the aperture stop 16, S8 is the image side surface of the fourth lens 14, S9 is the object side surface of the fourth lens 14, S10 is the image side surface of the fifth lens 15, S11 is the object side surface of the fifth lens 15, S12 is the image side surface of the cover glass 17, S13 is the object side surface of the cover glass 17, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0134] Among them, R is the radius of curvature of the optical element (such as a lens or a glass cover plate, etc.) at the corresponding position on the optical axis, Th is the surface thickness of the optical element in the direction along 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.

[0135] Table 4 shows the optical parameters of the lens 10 provided in the second embodiment.

[0136] f1 (mm) 116.747 EFL (mm) 35.07 f2 (mm) 81.496 TTL (mm) 90.46 f3 (mm) -78.113 Fno 1.0 f4 (mm) 41.662 BFL (mm) 29.84 f5 (mm) 62.661 R1 (mm) -101.6 R2 (mm) 210.16 FOV (°) 22.3

[0137] Wherein, EFL is the focal length of the lens 10, FOV is the maximum field of view angle of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens 10, R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens 10, 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, and f5 is the focal length of the fifth lens 15.

[0138] Figure 8 is Figure 7 the spherical aberration diagram of the lens in Figure 8 In Figure 8 , the ordinate represents the normalized pupil coordinate, and the abscissa represents the aberration in the axial direction, with the unit of millimeter. In Figure 8 , 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 passing through the lens 10 of this embodiment. It can be seen from

[0139] Figure 9 is Figure 8 the astigmatism field curvature diagram of the lens in Figure 10 is Figure 8 the distortion diagram of the lens in Figure 9 In Figure 10 , S represents the field curvature value of the light with a wavelength of 525 nm in the meridional image plane, and T represents the field curvature value of the light with a wavelength of 525 nm in the sagittal image plane. In Figure 9 and Figure 10 , it can be known that the lens 10 provided in this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0140] Figure 11 This is the structural schematic diagram of the third projection device provided in the third embodiment of the present application.

[0141] Refer to Figure 11As shown, the projection device 120 may include a lens 10 and a modulation unit 22. Among them, the lens 10 includes a first lens 11, a second lens 12, a third lens 13, a diaphragm 16, a fourth lens 14, a fifth lens 15, and a cover glass 17 arranged in sequence from the image side to the object side. The first lens 11 is closest to the image side, and the image side surface of the first lens 11 is concave. The fifth lens 15 is closest to the image side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, and the projection chip may be a DMD or an LCOS.

[0142] Among them, the first lens 11 has a positive optical power, and the ratio of the focal length f1 of the first lens 11 to the focal length EFL of the lens 10: |f1 / EFL| = 3.138. The second lens 12 has a positive optical power, and the ratio of the focal length f2 of the second lens 12 to the focal length EFL of the lens 10: |f2 / EFL| = 2.585. The third lens 13 has a negative optical power, and the ratio of the focal length f3 of the third lens 13 to the focal length EFL of the lens 10: |f3 / EFL| = 2.224. The fourth lens 14 has a positive optical power, and the ratio of the focal length f4 of the fourth lens 14 to the focal length EFL of the lens 10: |f4 / EFL| = 1.188. The fifth lens 15 has a positive optical power, and the ratio of the focal length f5 of the fifth lens 15 to the focal length EFL of the lens 10: |f5 / EFL| = 1.728.

[0143] The lens closest to the image side in the lens 10 is the first lens 11. The radius of curvature R1 of the image side surface of the first lens 11 = -132.25 mm, which is greater than -152 mm and less than -99 mm, meeting the requirements. The ratio of the radius of curvature R1 of the image side surface of the first lens 11 to the focal length EFL of the lens 10, R1 / EFL = -3.77, is greater than -4 and less than -2, meeting the requirements.

[0144] The lens closest to the object side in the lens 10 is the fifth lens 15. The radius of curvature R2 of the object side surface of the fifth lens 15 = 199.505 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of the fifth lens 15 to the focal length EFL of the lens 10, R2 / EFL = -5.688, is greater than -10 and less than 10, meeting the requirements.

[0145] The ratio of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10, BFL / EFL = 0.8502, is greater than 0.8 and less than 0.9, meeting the requirements.

[0146] The focal length EFL of the lens 10 = 35.075 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0147] Table 5 shows the optical parameters of each optical element in the projection device 120 provided in the third embodiment.

[0148]

[0149]

[0150] 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 aperture stop 16, S8 is the image side of the fourth lens 14, S9 is the object side of the fourth lens 14, S10 is the image side of the fifth lens 15, S11 is the object side of the fifth lens 15, S12 is the image side of the cover glass 17, S13 is the object side of the cover glass 17, OBJ is the projection plane (object plane), and ImgH is the imaging plane.

[0151] Among them, R is the radius of curvature of the optical element (such as a lens or a glass cover plate, etc.) at the corresponding position on the optical axis, Th is the surface thickness of the optical element in the direction along the optical axis, Nd is the refractive index of the d-line irradiated on each optical element, and Vd is the Abbe number of the optical element.

[0152] Table 6 shows the optical parameters of the lens 10 provided in the third embodiment.

[0153] f1 (mm) 110.074 EFL (mm) 35.075 f2 (mm) 90.656 TTL (mm) 90.53 f3 (mm) -78.009 Fno 1.0 f4 (mm) 41.682 BFL (mm) 29.83 f5 (mm) 60.612 R1 (mm) -132.25 R2 (mm) 199.505 FOV (°) 22.3

[0154] Among them, EFL is the focal length of the lens 10, FOV is the maximum field of view angle of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 10, R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 10, 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, and f5 is the focal length of the fifth lens 15.

[0155] Figure 12 For Figure 11 the spherical aberration diagram of the lens in Figure 12 In Figure 12 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 it can be seen that in this embodiment, the axial aberration is controlled within a very small range, and good correction is obtained.

[0156] Figure 13 is Figure 11 the astigmatism field curvature diagram of the lens in Figure 14 is Figure 11 the distortion diagram of lens 10 in Figure 13 wherein, S represents the field curvature value of light with a wavelength of 525 nm in the meridional image plane, and T represents the field curvature value of light with a wavelength of 525 nm in the sagittal image plane. In Figure 14 wherein, the solid line represents the distortion value of light with a central wavelength of 525 nm passing through lens 10 of this embodiment. In this embodiment, by combining Figure 13 and Figure 14 it can be known that the lens 10 provided by this embodiment controls the field curvature and distortion within the corresponding ranges and can meet the usage requirements.

[0157] In the description of the embodiments of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or an indirect connection through an intermediate medium, and it 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.

[0158] The devices or components indicated in the embodiments of the present application or implied must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to 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 specifically and precisely specified.

[0159] The terms "first", "second", "third", "fourth", etc. (if any) in the description of the embodiments, the claims, and the above drawings of the present application are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that 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 includes 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.

[0160] As used herein, the term "a plurality of" means two or more. The term "and / or" herein merely describes an associated relationship between associated objects and indicates that three relationships may exist. For example, A and / or B may represent three cases: A exists alone, both 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.

[0161] It should be understood that the various numerical numbers involved in the embodiments of the present application are only for convenience of description and are not used to limit the scope of the embodiments of the present application.

[0162] It should be understood that in the embodiments of the present application, the magnitude of the serial numbers of the above processes does not mean the sequence of execution, and the execution sequence 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, Comprising at least five lenses arranged from the image side to the object side; The image side surface of the lens closest to the image side in the lens is concave, the number of lenses with positive refractive power in the lens is at least three, and the number of lenses with negative refractive power in the lens is at least one, wherein: When the number of lenses with negative refractive power is one, the lens with negative refractive power is disposed between the lens closest to the image side in the lens and the lens closest to the object side in the lens.

2. The lens according to claim 1, wherein, The lens satisfies the relationship: 0.8 < BFL / EFL < 0.9, where BFL is the back focal length of the lens and EFL is the focal length of the lens.

3. The lens according to claim 1 or 2, characterized in that, The lens satisfies the relationship: 33 mm < EFL < 38 mm, where EFL is the focal length of the lens.

4. The lens according to any one of claims 1 to 3, characterized in that The lens satisfies the relationship: -4 < R1 / EFL < -2, 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.

5. The lens according to any one of claims 1 to 4, characterized in that The lens satisfies the relationship: -152 mm < R1 < -99 mm, where R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens.

6. The lens according to any one of claims 1 to 5, characterized in that, The lens satisfies the relationship: -10 < R2 / EFL < 10, 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.

7. The lens according to any one of claims 1 to 6, characterized in that, The lens satisfies the relationship: -380 mm < R2 < 380 mm, where R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens.

8. The lens according to any one of claims 1 to 7, characterized in that, The lens closest to the image side in the lens has positive refractive power.

9. The lens according to any one of claims 1 to 8, characterized in that, The lens closest to the object side in the lens has positive refractive power.

10. A projection device, characterized in that, Comprising a display unit and a lens according to any one of claims 1 to 9, the display unit being configured to emit imaging light towards the lens.

11. The projection device according to claim 10, wherein The display unit comprises a light source unit and a modulation unit; The modulation unit is configured to modulate the light beam emitted by the light source unit to generate the imaging light and emit the imaging light towards the lens.

12. The projection device according to claim 11, wherein The display unit further comprises a reflection unit configured to reflect the light beam emitted by the light source unit to the modulation unit.

13. A vehicle lamp device, characterized in that, Comprising a housing and a projection device according to any one of claims 10 to 12, at least a part of the projection device being disposed inside the housing.

14. A vehicle, characterized in that, Comprising a vehicle headlamp device according to claim 13.

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