Lens, projection device, vehicle lamp device, and vehicle

Abstract

Embodiments of the present application relate to the technical field of optics, and provide a lens, a projection device, a vehicle lamp device, and a vehicle. The lens comprises at least six lens elements arranged from an image side to an object side. The lens element in the lens closest to the image side has positive focal power, the lens has at least three lens elements having positive focal power, and the lens has at least one lens element having negative focal power. The lens satisfies the relation: 33 mm<EFL<38 mm, wherein EFL is the focal length of the lens. Such arrangement allows the lens to have both a large aperture and a wide field of view.

Description

Lenses, projection devices, vehicle lighting devices, and vehicles

[0001] This application claims priority to Chinese Patent Application No. 202410487235.1, filed on April 22, 2024, entitled "Lens, Projection Device, Vehicle Lighting Device and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of optical technology, and in particular to a lens, a projection device, a vehicle lighting device, and a vehicle. Background Technology

[0003] With the development of intelligent vehicle technology, vehicle headlights are required to not only have traditional lighting functions but also the ability to project patterns to meet increasing demands for welcoming guests, information interaction, and autonomous driving. Therefore, to meet these growing needs, the optical specifications of projectable headlights are becoming increasingly stringent. For example, they require a wide field of view (FOV), which is a crucial indicator of the amount of projected information; a larger FOV means a greater amount of information can be projected. However, the lenses in projectable headlights cannot simultaneously possess both a large aperture and a large FOV. Summary of the Invention

[0004] This application provides a lens, a projection device, a vehicle lighting device, and a vehicle, which can enable the lens to simultaneously possess a large aperture and a large field of view.

[0005] The first aspect of this application provides a lens comprising at least six lens elements arranged from the image side to the object side. The lens element closest to the image side has positive optical power, the lens has at least three lenses with positive optical power, and the lens has at least one lens with negative optical power. The lens satisfies the relationship: 33mm < EFL < 38mm, where EFL is the focal length of the lens.

[0006] The lens provided in this application embodiment is composed of at least six lenses. At least three lenses have positive optical power, at least one lens has negative optical power, and the lens closest to the image side has positive optical power. This allows for a large field of view while maintaining an Fno of less than or equal to 1.3, thus enabling the lens to simultaneously possess both a large aperture and a large field of view. Furthermore, the lens has a focal length greater than 33mm and less than 38mm, achieving a field of view greater than 20° x 10° while maintaining a large aperture. Here, 20° refers to the field of view in the horizontal direction, and 10° refers to the field of view in the vertical direction. Therefore, the lens provided in this application embodiment can achieve a projection field of view greater than 20° x 10° while maintaining an Fno of ≤ 1.3, thus meeting projection requirements.

[0007] In one possible implementation, the lens satisfies the relationship: BFL / EFL ≥ 0.846, where BFL is the back focal length of the lens and EFL is the focal length of the lens.

[0008] The lens provided in this application, after satisfying the relationship BFL / EFL≥0.846, can avoid the optical path of the lens being too long or too short, which is beneficial for the design and setting of the rear optical path. In addition, it can also ensure that the lens has the characteristics of both large aperture and large field of view.

[0009] In one possible implementation, the lens satisfies the relationship: 6 < R1 / EFL < 50, where R1 is the radius of curvature of the image side of the lens closest to the image side, and EFL is the focal length of the lens.

[0010] The lens provided in this application, by satisfying the relationship 6 < R1 / EFL < 50, can simultaneously achieve a large aperture and a large field of view while reducing the manufacturing difficulty of the lens closest to the image side, improving yield, and thus enhancing economic efficiency. Furthermore, it facilitates aberration correction. In addition, it avoids the image side of the lens closest to the image side being too protruding or too flat. An overly protruding image side may cause interference with other components, while an overly flat image side can affect the design of vehicle headlights.

[0011] In one possible implementation, the lens satisfies the relationship: 198mm < R1 < 1500mm, where R1 is the radius of curvature of the image side of the lens closest to the image side.

[0012] The lens provided in this application, by satisfying the relationship 198mm < R1 < 1500mm, can simultaneously achieve a large aperture and a wide field of view while reducing the manufacturing difficulty of the lens element closest to the image side, improving yield, and thus enhancing economic efficiency. Furthermore, it facilitates aberration correction. In addition, it avoids the image side of the lens element closest to the image side from being too protruding or too flat, effectively balancing the lens's optical performance and the headlight design.

[0013] In one possible implementation, the lens satisfies the relationship: 4 < R2 / EFL < 16, where R2 is the radius of curvature of the object side of the lens closest to the object side, and EFL is the focal length of the lens.

[0014] The lens provided in this application, by satisfying the relationship 4 < R² / EFL < 16, can simultaneously achieve a large aperture and a large field of view, while reducing the manufacturing difficulty of the lens closest to the object side, improving yield, and thus enhancing economic efficiency. Furthermore, it avoids the object side of the lens closest to the object side being too protruding or too concave. An excessively protruding object side can interfere with other optical elements, compress the optical space between the lens and the projection chip, or even damage the object-side lens. An excessively concave object side is detrimental to aberration correction.

[0015] In one possible implementation, the lens satisfies the relationship: 140mm < R2 < 560mm, where R2 is the radius of curvature of the object side of the lens closest to the object side.

[0016] The lens provided in this application satisfies the relationship 140mm < R2 < 560mm. It can simultaneously achieve a large aperture and a wide field of view while reducing the manufacturing difficulty of the lens element closest to the object side, improving yield and thus enhancing cost-effectiveness. Furthermore, it avoids the object side of the lens element closest to the object side from being too protruding or too concave, effectively balancing the lens's optical performance and the headlight design.

[0017] In one possible implementation, the lens closest to the object side of the lens has positive optical power.

[0018] The lens provided in this application improves optical performance by setting the lens closest to the object side to have positive optical power, thereby increasing the amount of light entering the lens. Additionally, it also improves the lens's cost-effectiveness.

[0019] In one possible implementation, at least six lenses include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially from the image side to the object side. The first lens is closest to the image side and has positive optical power, while the sixth lens is closest to the object side. This arrangement reduces the number of lenses while simultaneously achieving a large field of view and a large aperture, thus improving the lens's cost-effectiveness.

[0020] The first aspect of this application includes two projection devices, comprising a display unit and a lens as described in any of the first aspects, wherein the display unit is used to emit imaging light to the lens.

[0021] In one possible implementation, the display unit includes a light source unit and a modulation unit. The modulation unit modulates the light beam emitted from the light source unit to generate imaging light and emits the imaging light towards the lens.

[0022] In one possible implementation, the display unit further includes a reflection unit for reflecting the light beam emitted from the light source unit to the modulation unit.

[0023] A third aspect of this application provides a vehicle lighting device, including a housing and a projection device as described in any of the second aspects, wherein at least a portion of the projection device is disposed inside the housing.

[0024] The fourth aspect of this application is a means of transportation, including the vehicle lighting device as described in the third aspect. Attached Figure Description

[0025] Figure 1 is a structural schematic diagram of a vehicle lighting device provided in an embodiment of this application;

[0026] Figure 2 is a schematic diagram of the structure of a lens provided in an embodiment of this application;

[0027] Figure 3 is a schematic diagram of the structure of the first projection device provided in Embodiment 1 of this application;

[0028] Figure 4 shows the spherical chromatic aberration of the lens in Figure 3;

[0029] Figure 5 is the image bokeh curve of the lens in Figure 3;

[0030] Figure 6 shows the distortion diagram of the lens in Figure 3;

[0031] Figure 7 is a schematic diagram of the structure of the second projection device provided in Embodiment 2 of this application;

[0032] Figure 8 shows the spherical chromatic aberration of the lens in Figure 7;

[0033] Figure 9 is a bokeh curve of the lens in Figure 7;

[0034] Figure 10 shows the distortion of the lens in Figure 7.

[0035] Explanation of reference numerals in the attached drawings: 100, vehicle lighting device; 110, housing; 120, projection device; 10, lens; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 16, sixth lens; 17, aperture; 18, cover glass; 20, display unit; 21, light source unit; 211, light source; 212, collimation unit; 22, modulation unit; 23, reflection unit. Detailed Implementation

[0036] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0037] To facilitate understanding, the relevant technical terms involved in the embodiments of this application will first be explained and described.

[0038] 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 vertical distance from the optical center of a lens or lens group to the focal plane when a scene at infinity is formed into a clear image on the focal plane.

[0039] The image side is the side where the image is located, with the lens as the boundary. The side of the lens that faces the image side is the image-side surface of the lens.

[0040] The object side is the side where the modulation unit is located, and the side of the lens facing the object side is the object side.

[0041] Total track length (TTL) refers to the total length from the vertex of the first lens element located near the object side to the image plane of the lens; it is also known as the total optical length.

[0042] Back focal length (BFL) is defined as the distance from the lens element closest to the imaging plane to the modulation unit.

[0043] Optical power is the ability of a lens to refract a parallel beam of light incident from an incident lens.

[0044] Positive focal length means that the lens has a positive focal length and has the effect of converging light.

[0045] Negative power means that the lens has a negative focal length, which has the effect of diverging light.

[0046] Aperture is a device used to control the amount of light passing through the lens into an electronic device. It is usually expressed in the lens using the F# (F-number) value.

[0047] The aperture number F# is a relative value derived from the lens's focal length and the lens's light-gathering diameter (the reciprocal of the relative aperture). The smaller the aperture number F#, the more light enters the lens in the same unit of time.

[0048] The cover glass (CG) is used to protect the projection chip.

[0049] A modulation unit is used to modulate the light beam emitted by a light source to generate imaging light that forms an image.

[0050] Digital micromirror devices (DMDs) are used to reflect light to form images.

[0051] Liquid crystal on silicon (LCOS) is used to reflect light.

[0052] Axial chromatic aberration, also known as longitudinal chromatic aberration or positional chromatic aberration, occurs when a beam of light parallel to the optical axis converges at different positions after passing through a lens. This aberration is called positional chromatic aberration or axial chromatic aberration. This is because the lens images different wavelengths of light at different positions, causing the images of different colors of light to not completely overlap during the final imaging process, resulting in the dispersion of polychromatic light.

[0053] Distortion, also known as image distortion, refers to the degree of distortion in the image formed by an optical system relative to the object itself. Distortion occurs due to aperture aberration; the height of the intersection point between the principal ray from different fields of view and the Gaussian image plane after passing through the optical system is not equal to the ideal image height, and this difference is the distortion. Therefore, distortion only changes the imaging position of an off-axis object point on the ideal plane, causing distortion in the image shape, but it does not affect the image's sharpness.

[0054] With the development of intelligent vehicle technology, vehicle headlights need to not only have traditional lighting functions but also the ability to project patterns to meet increasingly diverse needs such as welcoming guests, information interaction, and autonomous driving. Therefore, to meet these growing demands, the optical requirements for projecting headlights will become increasingly stringent. For example, headlights are required to have a wide field of view (FOV), which is a crucial indicator of the amount of projected information; a larger FOV means a greater amount of information can be projected.

[0055] However, the lenses in projector headlights cannot simultaneously possess both a large aperture and a wide field of view, failing to meet diverse projection needs. Therefore, how to enable lenses to simultaneously possess both a large aperture and a wide field of view has become an urgent problem to be solved.

[0056] In view of this, embodiments of this application provide a lens 10, a projection device 120, a vehicle lighting device 100, and a vehicle. The lens 10 can simultaneously possess the characteristics of a large aperture and a large field of view, thereby improving the projection range and brightness to meet usage requirements.

[0057] The means of transportation may include, but is not limited to, cars, trucks, motorcycles, buses, boats, airplanes, helicopters, lawnmowers, recreational vehicles, amusement park vehicles, construction equipment, trams, golf carts, trains, or handcarts. In this embodiment, a car is used as an example for illustration.

[0058] The vehicle includes a vehicle body and a lighting device 100, which is mounted on the vehicle body. The lighting device 100 may include, but is not limited to, pixel display lights, near-field welcome lights, pedestrian or interactive lights, and headlights. For example, in this embodiment, the lighting device 100 is described as a car headlight. The lighting device 100 emits illumination light for lighting purposes, improving vehicle safety. It also emits imaging light for projection imaging, fulfilling display requirements.

[0059] Figure 1 is a structural schematic diagram of a vehicle lighting device 100 provided in an embodiment of this application.

[0060] Referring to Figure 1, the vehicle lighting device 100 may include a housing 110 and a projection device 120. At least a portion of the projection device 120 is disposed within the housing 110; for example, as shown in Figure 1, the projection device 120 is disposed inside the housing 110. Alternatively, the projection device 120 may be partially disposed inside the housing 110 and partially disposed outside the housing 110. The projection device 120 serves to project images and display lighting.

[0061] Referring to Figure 1, the projection device 120 may include a display unit 20 and a lens 10. The display unit 20 is used to emit imaging light to the lens 10. The lens 10 can emit imaging light to the outside of the housing 110 to form an image on the outside of the housing 110 or to provide illumination.

[0062] For example, referring to FIG1, the display unit 20 may include a light source unit 21 and a modulation unit 22. The modulation unit 22 is used to modulate the light beam emitted from the light source unit 21 to generate imaging light and emit the imaging light to the lens 10.

[0063] The specific structure of the modulation unit 22 is not limited here. For example, the modulation unit 22 may include a projection chip, which can modulate the light beam emitted by the light source unit 21 and generate imaging light that is directed toward the lens 10.

[0064] The projection chip may include, but is not limited to, DMD, LCOS, MEMS, or LCD.

[0065] In some possible implementations, continuing to refer to Figure 1, the light source unit 21 may include a light source 211 and a collimation unit 212. The collimation unit 212 is used to collimate the light emitted by the light source 211, and the modulation unit 22 is used to modulate the collimated light to generate imaging light emitted to the lens 10.

[0066] In some possible implementations, continuing to refer to Figure 1, the display unit 20 may further include a reflection unit 23, which reflects the light beam emitted from the light source unit 21 to the modulation unit 22. Specifically, as shown in Figure 1, the collimation unit 212 emits the collimated light beam to the reflection unit 23, and the reflection unit 23 reflects the collimated light beam to the modulation unit 22, ensuring that the modulation unit 22 modulates the collimated light beam.

[0067] The specific structure of the reflecting unit 23 is not limited here. For example, continuing to refer to Figure 1, the reflecting unit 23 can be a curved mirror, and the curved surface of the mirror reflects the light emitted by the light source unit 21 to the modulation unit 22.

[0068] It should be noted that the optical path in Figure 1 is only a schematic diagram, and other optical path schemes may also be used, which will not be described in detail here.

[0069] It should also be noted that, in addition to its application in the vehicle lighting device 100 for projection imaging and display lighting, the projection device 120 provided in this application embodiment can also be applied to devices such as projectors, head-up displays, and augmented reality (AR) glasses to perform projection imaging.

[0070] The lens 10 provided in the embodiments of this application will now be described with reference to the accompanying drawings.

[0071] Figure 2 is a schematic diagram of the structure of a lens 10 provided in an embodiment of this application.

[0072] The lens 10 provided in this application embodiment includes at least six lenses arranged from the image side to the object side. For example, as shown in FIG2, the lens 10 may include six lenses arranged sequentially from the image side to the object side. Of course, the number of lenses may be more than six. The six lenses are a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15, and a sixth lens 16 arranged sequentially from the image side to the object side. The first lens 11 is closest to the image side, and the sixth lens 16 is closest to the object side. This arrangement can reduce the number of lenses while achieving a large field of view and a large aperture, which is beneficial to improving the economy of the lens 10.

[0073] The lens closest to the image side in lens 10 has positive optical power, for example, as shown in Figure 2, the first lens 11 has positive optical power. Lens 10 has at least three lenses with positive optical power, and at least one lens with negative optical power, for example, as shown in Figure 2, four of the six lenses have positive optical power and the other two have negative optical power, or five of the six lenses have positive optical power and the other lens has negative optical power. Lens 10 satisfies the relationship: 33mm < EFL < 38mm, where EFL is the focal length of lens 10.

[0074] Lens 10 employs the following architecture: it consists of at least six lenses, with at least three lenses having positive optical power and at least one lens having negative optical power. The lens closest to the image side has positive optical power. Lens 10 has a focal length greater than 33mm and less than 38mm, achieving a large field of view greater than 20° x 10° with an Fno less than or equal to 1.3. This allows lens 10 to simultaneously possess both a large aperture and a large field of view, meeting projection requirements. Here, 20° refers to the field of view of lens 10 in the horizontal direction, and 10° refers to the field of view of lens 10 in the vertical direction. Furthermore, having the lens closest to the image side have positive optical power improves the economic efficiency of lens 10 while simultaneously achieving a large aperture and a large field of view.

[0075] In this embodiment of the application, the specific value of the focal length of the lens 10 is not limited, and may include, but is not limited to, 33.1mm, 33.5mm, 33.88mm, 33.9mm, 34mm, 34.5mm, 35mm, 35.3mm, 36mm, 37mm or 37.5mm.

[0076] Each lens element in lens 10 can be made of the same material; for example, each lens element can be made of optical glass or plastic.

[0077] In some possible implementations, lens 10 can also satisfy the relationship: BFL / EFL≥0.846, where BFL is the back focal length of lens 10 and EFL is the focal length of lens 10.

[0078] Correspondingly, after satisfying the relationship: BFL / EFL≥0.846, the optical path of lens 10 can be avoided to be too long or too short, which is beneficial for the design and setting of the rear optical path. In addition, it can also ensure that lens 10 has the characteristics of both large aperture and large field of view.

[0079] The specific ratio of BFL to EFL is not limited here, and may include, but is not limited to, 0.846, 0.847, 0.848, 0.849, 0.85, 0.8591, 0.86, 0.87, 0.88, or 0.89.

[0080] In some possible implementations, the lens 10 can also satisfy the relationship: 6 < R1 / EFL < 50, where R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 10, and EFL is the focal length of the lens 10.

[0081] Correspondingly, lens 10 satisfies the relationship: 6 < R1 / EFL < 50. This allows for the simultaneous achievement of a large aperture and a wide field of view while reducing the manufacturing difficulty of the lens closest to the image side, improving yield, and enhancing economic efficiency. Furthermore, it facilitates aberration correction. In addition, it avoids the image side of the lens closest to the image side being too protruding or too flat. An overly protruding image side may cause interference with other components, while an overly flat image side will affect the shape of the headlights.

[0082] The specific ratio of R1 / EFL is not limited here, and can include, but is not limited to, 6.5, 7, 7.5, 8, 8.5, 8.9, 9, 9.5, 9.9, 10, 10.5, 11, 12, 13, 14.5, 20, 25, 30, 35, 40, 45, 48, 49.5, etc.

[0083] In some possible implementations, the lens 10 can also satisfy the relationship: 198mm < R1 < 1500mm, where R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 10.

[0084] Correspondingly, lens 10 can also satisfy the relationship: 198mm < R1 < 1500mm. This allows for the simultaneous achievement of a large aperture and a wide field of view, while reducing the manufacturing difficulty of the lens closest to the image side, improving yield, and enhancing economic efficiency. Furthermore, it facilitates aberration correction. In addition, it avoids the image side of the lens closest to the image side being too protruding or too flat, effectively balancing the optical performance of lens 10 with the design of the vehicle headlights.

[0085] The specific value of R1 is not limited here, and it can be, but is not limited to, 199mm, 200mm, 250mm, 300mm, 350mm, 390.5mm, 400mm, 480.95mm, 500mm, 600mm, 670mm, 700mm, 790mm, 800mm, 900mm, 1000mm, 1100mm, 1200mm, 1300mm, 1450mm, or 1499.5mm.

[0086] In some possible implementations, the lens 10 can also satisfy the relationship: 4 < R2 / EFL < 16, where R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 10, and EFL is the focal length of the lens 10.

[0087] Correspondingly, lens 10 satisfies the relationship: 4 < R² / EFL < 16. This allows for the simultaneous achievement of a large aperture and a wide field of view, while reducing the manufacturing difficulty of the lens closest to the object side, improving yield, and enhancing economic efficiency. Furthermore, it avoids the object side of the lens closest to the object side being too protruding or too concave. An excessively protruding object side can interfere with other optical components, compress the optical space between lens 10 and the projection chip, or damage the object-side lens. An excessively concave object side is detrimental to aberration correction.

[0088] The specific ratio of R2 / EFL is not limited here, and can include, but is not limited to, 4.3, 4.5, 5, 5.1, 5.159, 5.19, 5.195, 6, 7, 8, 9, 9.1, 9.22, 10, 10.5, 11, 11.654, 12, 12.5, 13, 13.5, 14, 14.5, 15, or 15.5, etc.

[0089] In some possible implementations, the lens 10 can also satisfy the relationship: 140mm < R2 < 560mm, where R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 10.

[0090] Correspondingly, lens 10 satisfies the relationship: 140mm < R2 < 560mm. This allows for the simultaneous achievement of a large aperture and a wide field of view, while reducing the manufacturing difficulty of the lens element closest to the object side, improving yield, and enhancing economic efficiency. Furthermore, it avoids the object side of the lens element closest to the object side being too protruding or too concave, effectively balancing the optical performance of lens 10 with the design of the vehicle headlights.

[0091] The specific value of R2 is not limited here, and can include, but is not limited to, 141mm, 145mm, 150mm, 160mm, 170mm, 180mm, 181mm, 182mm, 183mm, 184mm, 184.954mm, 200mm, 250mm, 300mm, 310mm, 340mm, 350mm, 355mm, 359mm, 360mm, 370mm, 400mm, 450mm, 500mm, 550mm, 555mm, or 559mm, etc.

[0092] In some possible implementations, the lens closest to the object side in lens 10 can have positive optical power, for example, as shown in Figure 2, the sixth lens 16 closest to the object side has positive optical power.

[0093] Correspondingly, by setting the lens closest to the object side as a lens with positive optical power, the amount of light entering the lens 10 can be increased, thereby improving optical performance. In addition, the economic efficiency of the lens 10 can also be improved.

[0094] It should be noted that the lens closest to the object side in lens 10 can have both positive and negative optical power.

[0095] In some possible implementations, at least one lens can be a spherical lens. For example, as shown in Figure 2, all six lenses in lens 10 can be spherical lenses. Of course, the number of spherical lenses can also be less than six.

[0096] Correspondingly, the more spherical mirrors in lens 10, the greater the reduction in the manufacturing difficulty of lens 10, which is beneficial to improving the yield rate. In addition, it can also improve the image quality.

[0097] In some possible implementations, as shown in Figure 2, the lens 10 may also include an aperture stop 17. The aperture stop 17 may be positioned between two adjacent lens elements in the lens 10. For example, as shown in Figure 2, the aperture stop 17 may be positioned between the fourth lens element 14 and the fifth lens element 15. Of course, the aperture stop 17 may also be positioned in other locations.

[0098] In some possible implementations, the lens 10 may also include a cover glass 18 (not shown in the figure). The cover glass 18 is disposed between the lens closest to the object side of the lens 10 and the modulation unit 22, and the cover glass 18 is used to protect the modulation unit 22.

[0099] In some possible implementations, the lens 10 may also include a filter (not shown) for correcting color deviation. The filter is disposed between the lens closest to the object side of the lens 10 and the modulation unit 22.

[0100] It should be noted that the lens 10 may have one of a cover glass 18 and a filter, or both.

[0101] The structure and performance of the projection device 120 provided in this application will be described below with reference to specific embodiments.

[0102] Figure 3 is a schematic diagram of the structure of the first projection device 120 provided in Embodiment 1 of this application.

[0103] Referring to Figure 3, the projection device 120 may include a lens 10 and a modulation unit 22. The lens 10 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, an aperture 17, a fifth lens 15, a sixth lens 16, and a cover glass 18, arranged sequentially from the image side to the object side. The first lens 11 is closest to the image side, the sixth lens 16 is closest to the object side, and the cover glass 18 is disposed between the sixth lens 16 and the modulation unit 22. The modulation unit 22 may include a projection chip, which may be a DMD or an LCOS.

[0104] The first lens 11 has 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 is: |f1 / EFL|=10.8.

[0105] The second lens element 12 has negative optical power, and the ratio of the focal length f2 of the second lens element 12 to the focal length EFL of the lens 10 is: |f2 / EFL|=-4.

[0106] The third lens element 13 has positive optical power, and the ratio of the focal length f3 of the third lens element 13 to the focal length EFL of the lens 10 is: |f3 / EFL|=2.44.

[0107] The fourth lens element 14 has negative optical power, and the ratio of the focal length f4 of the fourth lens element 14 to the focal length EFL of the lens 10 is: |f4 / EFL|=-0.65.

[0108] The fifth lens element 15 has positive optical power, and the ratio of the focal length f5 of the fifth lens element 15 to the focal length EFL of the lens 10 is: |f5 / EFL|=1.0.

[0109] The sixth lens element 16 has positive optical power, and the ratio of the focal length f6 of the sixth lens element 16 to the focal length EFL of the lens 10 is: |f6 / EFL|=1.82.

[0110] The materials of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 can all be optical glass or plastic. In addition, the surface shape of each lens can be a spherical surface representing the model.

[0111] The focal length (EFL) of lens 10 is 35.34mm, which is greater than 33mm and less than 38mm, thus meeting the requirements.

[0112] The lens closest to the image side in lens 10 is the first lens 11. The radius of curvature R1 of the image side of the first lens 11 is 557.2 mm, which is greater than 198 mm and less than 1500 mm, thus meeting the requirements. The ratio of the radius of curvature R1 of the image side of the first lens 11 to the focal length EFL of lens 10, R1 / EFL, is 15.77, which is greater than 6 and less than 50, thus meeting the requirements.

[0113] The lens element closest to the object side in lens 10 is the sixth lens element 16. The radius of curvature of the object side surface of the sixth lens element 16, R2, is 214.88 mm, which is greater than 140 mm and less than 560 mm, thus meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of the sixth lens element 16 to the focal length EFL of lens 10, R2 / EFL, is 6.08, which is greater than 4 and less than 16, thus meeting the requirements.

[0114] The back focal length (BFL) of lens 10 is 29.88mm, and the ratio of the back focal length (BFL) of lens 10 to the focal length (EFL) of lens 10, BFL / EFL = 0.846, meets the requirements.

[0115] Table 1 shows the optical parameters of each optical element in the projection device 120 provided in this embodiment.

[0116] Wherein, S1 is the image-side surface of the first lens 11, S2 is the equivalent surface formed by the bonding of the image-side surface of the first lens 11 and the image-side surface of the second lens 12, S3 is the image-side surface of the second lens 12, S4 is the image-side surface of the third lens 13, S5 is the object-side surface of the third lens 13, S6 is the image-side surface of the fourth lens 14, S7 is the object-side surface of the fourth lens 14, S8 is the aperture stop 17, S9 is the image-side surface of the fifth lens 15, S10 is the object-side surface of the fifth lens 15, S11 is the image-side surface of the sixth lens 16, S12 is the object-side surface of the sixth lens 16, S13 is the image-side surface of the cover glass 18, S14 is the object-side surface of the cover glass 18, OBJ is the projection surface (object surface), and ImgH is the imaging surface.

[0117] Where R is the radius of curvature of the optical element (such as a lens or glass cover) at the corresponding position on the optical axis, Th is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0118] Table 2 shows the optical parameters of the lens 10 provided in this embodiment.

[0119] Where EFL is the focal length of lens 10, Fno is the aperture of lens 10, BFL is the back focal length of lens 10, TTL is the total optical length of lens 10, R1 is the radius of curvature of the image side of the lens closest to the image side of lens 10, and R2 is the radius of curvature of the object side of the lens closest to the object side of 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, f5 is the focal length of the fifth lens 15, and f6 is the focal length of the sixth lens 16.

[0120] Figure 4 is a spherical chromatic aberration diagram of lens 10 in Figure 3.

[0121] In Figure 4, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 4, the three curves correspond to the axial aberration curves of light with wavelengths of 625 nm, 550 nm, and 455 nm after passing through the lens 10 of this embodiment. As can be seen from Figure 4, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0122] Figure 5 is the image bokeh curve of lens 10 in Figure 3, and Figure 6 is the distortion diagram of lens 10 in Figure 3.

[0123] In Figure 5, S represents the field curvature of light with a wavelength of 525 nm in the meridional image plane, and T represents the field curvature of light with a wavelength of 525 nm in the sagittal image plane. In Figure 6, the solid line represents the distortion value of light with a center wavelength of 525 nm passing through the lens 10 of this embodiment. In this embodiment, as can be seen from Figures 5 and 6, the lens 10 provided in this embodiment controls the field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0124] Figure 7 is a schematic diagram of the structure of the second projection device 120 provided in Embodiment 2 of this application.

[0125] Referring to Figure 7, the projection device 120 may include a lens 10 and a modulation unit 22. The lens 10 includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, an aperture 17, a fifth lens 15, a sixth lens 16, and a cover glass 18, arranged sequentially from the image side to the object side. The first lens 11 is closest to the image side, the sixth lens 16 is closest to the object side, and the cover glass 18 is disposed between the sixth lens 16 and the modulation unit 22. The modulation unit 22 may include a projection chip, which may be a DMD or an LCOS.

[0126] The materials of the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 can all be optical glass or plastic. In addition, the surface shape of each lens can be a spherical surface representing the model.

[0127] The first lens 11 has 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 is: |f1 / EFL|=9.654.

[0128] The second lens element 12 has negative optical power, and the ratio of the focal length f2 of the second lens element 12 to the focal length EFL of the lens 10 is: |f2 / EFL|=-3.912.

[0129] The third lens element 13 has positive optical power, and the ratio of the focal length f3 of the third lens element 13 to the focal length EFL of the lens 10 is: |f3 / EFL|=2.43.

[0130] The fourth lens element 14 has negative optical power. The ratio of the focal length f4 of the fourth lens element 14 to the focal length EFL of the lens 10 is: |f4 / EFL|=-0.646.

[0131] The fifth lens element 15 has positive optical power, and the ratio of the focal length f5 of the fifth lens element 15 to the focal length EFL of the lens 10 is: |f5 / EFL|=1.0.

[0132] The sixth lens element 16 has positive optical power, and the ratio of the focal length f6 of the sixth lens element 16 to the focal length EFL of the lens 10 is: |f6 / EFL|=1.82.

[0133] The focal length (EFL) of lens 10 is 35.34mm, which is greater than 33mm and less than 38mm, thus meeting the requirements.

[0134] The lens closest to the image side in lens 10 is the first lens 11. The radius of curvature R1 of the image side of the first lens 11 is 519.11 mm, which is greater than 198 mm and less than 1500 mm, thus meeting the requirements. The ratio of the radius of curvature R1 of the image side of the first lens 11 to the focal length EFL of lens 10, R1 / EFL, is 14.69, which is greater than 6 and less than 50, thus meeting the requirements.

[0135] The lens element closest to the object side in lens 10 is the sixth lens element 16. The radius of curvature of the object side surface of the sixth lens element 16, R2, is 255.52 mm, which is greater than 140 mm and less than 560 mm, thus meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of the sixth lens element 16 to the focal length EFL of lens 10, R2 / EFL, is 7.23, which is greater than 4 and less than 16, thus meeting the requirements.

[0136] The back focal length (BFL) of lens 10 is 29.88mm, and the ratio of the back focal length (BFL) of lens 10 to the focal length (EFL) of lens 10, BFL / EFL = 0.846, meets the requirements.

[0137] Table 3 shows the optical parameters of each optical element in the projection device 120 provided in this embodiment 2.

[0138] Wherein, S1 is the image-side surface of the first lens 11, S2 is the equivalent surface formed by the bonding of the image-side surface of the first lens 11 and the image-side surface of the second lens 12, S3 is the image-side surface of the second lens 12, S4 is the image-side surface of the third lens 13, S5 is the object-side surface of the third lens 13, S6 is the image-side surface of the fourth lens 14, S7 is the object-side surface of the fourth lens 14, S8 is the aperture stop 17, S9 is the image-side surface of the fifth lens 15, S10 is the object-side surface of the fifth lens 15, S11 is the image-side surface of the sixth lens 16, S12 is the object-side surface of the sixth lens 16, S13 is the image-side surface of the cover glass 18, S14 is the object-side surface of the cover glass 18, OBJ is the projection surface (object surface), and ImgH is the imaging surface.

[0139] Where R is the radius of curvature of the optical element (such as a lens or glass cover) at the corresponding position on the optical axis, Th is the surface thickness of the optical element along the optical axis, Nd is the refractive index of each optical element when d-line is incident on it, and Vd is the Abbe number of the optical element.

[0140] Table 4 shows the optical parameters of the lens 10 provided in this embodiment 2.

[0141] Where EFL is the focal length of lens 10, Fno is the aperture of lens 10, BFL is the back focal length of lens 10, TTL is the total optical length of lens 10, R1 is the radius of curvature of the image side of the lens closest to the image side of lens 10, and R2 is the radius of curvature of the object side of the lens closest to the object side of 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, f5 is the focal length of the fifth lens 15, and f6 is the focal length of the sixth lens 16.

[0142] Figure 8 is a spherical chromatic aberration diagram of lens 10 in Figure 7.

[0143] In Figure 8, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberration in the axial direction, in millimeters. In Figure 8, the three curves correspond to the axial aberration curves of light with wavelengths of 625 nm, 550 nm, and 455 nm after passing through the lens 10 of this embodiment. As can be seen from Figure 8, in this embodiment, the axial aberration is controlled within a very small range, achieving good correction.

[0144] Figure 9 is the image bokeh curve of lens 10 in Figure 7, and Figure 10 is the distortion diagram of lens 10 in Figure 7.

[0145] In Figure 9, S represents the field curvature of light with a wavelength of 525 nm in the meridional image plane, and T represents the field curvature of light with a wavelength of 525 nm in the sagittal image plane. In Figure 10, the solid line represents the distortion value of light with a center wavelength of 525 nm passing through the lens 10 of this embodiment. In this embodiment, as can be seen from Figures 9 and 10, the lens 10 provided in this embodiment controls the field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0146] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0147] The devices or elements referred to in the embodiments of this application or implied herein must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the embodiments of this application. In the description of the embodiments of this application, "a plurality of" means two or more, unless otherwise precisely specified.

[0148] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the present application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0149] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects; in formulas, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0150] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application.

[0151] It is understood that, in the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A lens, characterized in that, It includes at least six lenses arranged from the image side to the object side; The lens closest to the image side of the lens has positive optical power, and the number of lenses with positive optical power in the lens is at least three, while the number of lenses with negative optical power in the lens is at least one. The lens satisfies the following relationship: 33mm < EFL < 38mm, where EFL is the focal length of the lens.

2. The lens according to claim 1, characterized in that, The lens satisfies the following relationship: BFL / EFL≥0.846, 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 following relationship: 6 < R1 / EFL < 50, where R1 is the radius of curvature of the image side of the lens closest to the image side, and 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 following relationship: 198mm < R1 < 1500mm, where R1 is the radius of curvature of the image side of the lens closest to the image side.

5. The lens according to any one of claims 1 to 4, characterized in that, The lens satisfies the following relationship: 4 < R2 / EFL < 16, where R2 is the radius of curvature of the object side of the lens closest to the object side, 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 following relationship: 140mm < R2 < 560mm, where R2 is the radius of curvature of the object side of the lens closest to the object side.

7. The lens according to any one of claims 1 to 6, characterized in that, The lens closest to the object side in the lens has positive optical power.

8. The lens according to any one of claims 1 to 7, characterized in that, The at least six lenses include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged sequentially from the image side to the object side, wherein the first lens is closest to the image side and has positive optical power, and the sixth lens is closest to the object side.

9. A projection device, characterized in that, It includes a display unit and a lens as described in any one of claims 1 to 8, wherein the display unit is used to emit imaging light to the lens.

10. The projection device according to claim 9, characterized in that, The display unit includes a light source unit and a modulation unit; The modulation unit is used to modulate the light beam emitted from the light source unit to generate the imaging light, and to emit the imaging light into the lens.

11. The projection device according to claim 10, characterized in that, The display unit further includes a reflection unit, which is used to reflect the light beam emitted from the light source unit to the modulation unit.

12. A vehicle lighting device, characterized in that, It includes a housing and a projection device as described in any one of claims 9 to 11, wherein at least a portion of the projection device is disposed inside the housing.

13. A means of transportation, characterized in that, Includes the vehicle lighting device as described in claim 12.

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