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. Wherein 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. The lens closest to the image side in the lens has positive focal power, the lens closest to the image side in the lens is made of plastic, and at least one of the image side surface and the object side surface of the lens closest to the image side in the lens is an aspheric surface. The lens meets the relational expression that EFL is larger than 33 mm and smaller than 38 mm, and EFL is the focal length of the lens. Through the arrangement, the lens can have a large aperture and a large field angle at the same time, and the economical efficiency and the optical performance of the lens can be improved.

Description

Technical Field

[0001] 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

[0002] 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 increasing demands for welcoming guests, information interaction, and autonomous driving. Therefore, to meet these growing needs, the optical requirements for headlights capable of projecting patterns are becoming 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 projectable information. However, current lenses used in projectable headlights, while possessing a large FOV, lack a large aperture. Summary of the Invention

[0003] This application provides a lens, a projection device, a vehicle lighting device, and a vehicle, which can enable the lens to have both a large aperture and a large field of view, and can improve the lens's economy and optical performance.

[0004] This application provides a lens comprising at least five lenses arranged from the image side to the object side. At least three lenses in the lens have positive optical power, and at least one lens has negative optical power. The lens closest to the image side has positive optical power, and the lens closest to the image side is made of plastic. At least one of the image side and the object side of the lens closest to the image side is aspherical. The lens satisfies the relationship: 33mm < EFL < 38mm, where EFL is the focal length of the lens.

[0005] The lens provided in this application embodiment has at least three lenses with positive optical power and at least one lens with negative optical power, the lens closest to the image side has positive optical power, and the focal length of the lens is between 33mm and 38mm. This allows for a projection field of view greater than 20° x 10° with Fno ≤ 1.0, enabling the lens to simultaneously possess both a large aperture and a large field of view. Here, 20° refers to the field of view in the horizontal direction, and 10° refers to the field of view in the vertical direction. Furthermore, increasing the back focal length of the lens facilitates the rear optical path arrangement, thereby improving image quality.

[0006] In addition, the lens element closest to the image side has positive optical power, and its material is plastic. This reduces lens costs while maintaining optical performance, significantly improving the lens's economic efficiency. Finally, at least one of the image-side and object-side surfaces of the lens element closest to the image side is aspherical, making it an aspherical lens. This corrects aberrations, improving overall lens performance and further enhancing optical performance.

[0007] In one possible implementation, the lens satisfies the relationship: 0.82 < BFL / EFL < 0.87, 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 0.82 < BFL / EFL < 0.87, 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: 0.8 < R1 / EFL < 3, 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 0.8 < R1 / EFL < 3, achieves both 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, balancing the lens's optical effect with the headlight design. An overly protruding image side of the lens may cause interference with other components, while an overly flat image side may affect the headlight design.

[0011] In one possible implementation, the lens satisfies the relationship: 28mm < R1 < 107mm, 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 28mm < R1 < 107mm, can simultaneously achieve a large aperture and a large 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: 0.8 < R2 / EFL < 2, 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 0.8 < R² / EFL < 2, 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, balancing the lens's optical effect with the headlight design. An excessively protruding object side of the lens closest to the object side can interfere with other optical components, compress the optical space between the lens and the projection chip, or damage the lens closest to the object side. An excessively concave object side of the lens closest to the object side is detrimental to aberration correction.

[0015] In one possible implementation, the lens satisfies the relationship: 28mm < R2 < 72mm, 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 28mm < R2 < 72mm. 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, a second aspect of this application provides a projection device including a display unit and a lens as described in any of the first aspects, wherein the display unit is configured to emit imaging light toward the lens.

[0018] 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.

[0019] 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.

[0020] A third aspect of this application provides a vehicle lighting device, which includes 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.

[0021] The fourth aspect of this application provides a means of transportation that includes the lighting device as described in the third aspect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of a vehicle lighting device provided in an embodiment of this application;

[0023] Figure 2 A schematic diagram of the structure of a lens provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of the first projection device provided in Embodiment 1 of this application;

[0025] Figure 4 for Figure 3 A spherical chromatic aberration diagram of the lens in the image;

[0026] Figure 5 for Figure 3 The image in the shot is like a fade-out curve;

[0027] Figure 6 for Figure 3 The distortion diagram of the lens in the image;

[0028] Figure 7 This is a schematic diagram of the structure of the second projection device provided in Embodiment 2 of this application;

[0029] Figure 8 for Figure 7 A spherical chromatic aberration diagram of the lens in the image;

[0030] Figure 9 for Figure 8 The image in the shot is like a fade-out curve;

[0031] Figure 10 for Figure 8 The distortion of the lens in the image.

[0032] Explanation of reference numerals in the attached figures:

[0033] 100. Vehicle lighting system;

[0034] 110. Outer shell;

[0035] 120. Projection device;

[0036] 10. Lens;

[0037] 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens;

[0038] 16. Aperture; 17. Cover glass;

[0039] 20. Display unit;

[0040] 21. Light source unit; 211. Light source; 212. Collimation unit;

[0041] 22. Modulation unit;

[0042] 23. Reflection unit. Detailed Implementation

[0043] 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.

[0044] To facilitate understanding, the relevant technical terms involved in the embodiments of this application will first be explained and described.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] Back focal length (BFL) is defined as the distance from the lens element closest to the imaging plane to the modulation unit.

[0050] Optical power is the ability of a lens to refract a parallel beam of light incident from an incident lens.

[0051] Positive focal length means that the lens has a positive focal length and has the effect of converging light.

[0052] Negative power means that the lens has a negative focal length, which has the effect of diverging light.

[0053] 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.

[0054] 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.

[0055] The cover glass (CG) is used to protect the projection chip.

[0056] A modulation unit is used to modulate the light beam emitted by the light source to generate image light that forms an image.

[0057] Digital micromirror devices (DMDs) are used to reflect light to form images.

[0058] Liquid crystal on silicon (LCOS) is used to reflect light.

[0059] 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.

[0060] 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.

[0061] 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 in areas such as welcoming guests, information interaction, and autonomous driving. Therefore, to meet these growing demands, the optical requirements for headlights capable of projecting patterns will become increasingly stringent. For example, headlights will need 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.

[0062] However, lenses used in automotive headlights in related technologies cannot simultaneously possess both a large aperture and a wide field of view, failing to meet usage requirements. Furthermore, the excessively long optical path of these lenses leads to an insufficiently short rear-end optical path, increasing the difficulty of arranging components along the rear-end optical path. In addition, the poor optical performance of these lenses results in low image quality.

[0063] In view of this, embodiments of this application provide a lens, a projection device, a vehicle lighting device, and a vehicle. This lens simultaneously possesses the characteristics of a large aperture and a large field of view, meeting projection requirements. Furthermore, the optical path length of the lens is within a suitable range, increasing the length of the rear optical path and reducing the difficulty of rear optical path arrangement. In addition, by setting the lens near the image side as an aspherical lens, aberration correction is facilitated, further improving optical performance and thus image quality. At the same time, the lens near the image side is made of plastic, reducing lens cost and improving the lens's economic efficiency.

[0064] The vehicles provided in this application embodiment may include, but are not limited to, automobiles, trucks, motorcycles, boats, airplanes, helicopters, lawnmowers, recreational vehicles, amusement park vehicles, construction equipment, trams, golf carts, trains, or handcarts. Furthermore, the vehicles provided in this application embodiment may also be new vehicles that will emerge in the future.

[0065] The vehicle can be an electric vehicle, a gasoline-powered vehicle, or a hybrid vehicle, such as a pure electric vehicle, a range-extended electric vehicle, a new energy vehicle, a fuel cell vehicle, or a hybrid electric vehicle. Exemplarily, in this embodiment, a vehicle is used as an example of the aforementioned means of transportation.

[0066] The vehicle provided in this application includes a lighting device and a vehicle body. The vehicle body may include components such as seats, dashboards, and body panels that complete the structure or function of the vehicle. The lighting device has both illumination and projection functions, capable of providing illumination or meeting projection requirements.

[0067] The vehicle lighting device may include, but is not limited to, pixel display vehicle lights, near-field welcome lights, pedestrian or interactive vehicle lights, and automotive headlights. For example, in this embodiment, an automotive headlight is used as an example of the aforementioned vehicle lighting device. The automotive headlight is installed at the front or rear of the vehicle, and while fulfilling lighting requirements, it can also fulfill projection requirements.

[0068] Figure 1 This is a schematic diagram of a vehicle lighting device provided in an embodiment of this application.

[0069] See Figure 1 As shown, 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... Figure 1 As shown, the projection device 120 is disposed inside the housing 110. Of course, the projection device 120 may also be partially disposed inside the housing 110 and partially disposed outside the housing 110. The projection device 120 is used for projection imaging and display illumination.

[0070] See also Figure 1 As shown, 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.

[0071] See also Figure 1 As shown, the display unit 20 includes 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.

[0072] See also the following for some possible implementations. Figure 1 As shown, the display unit 20 may also include a reflection unit 23, which is used to reflect the light beam emitted from the light source unit 21 to the modulation unit 22.

[0073] The specific structure of the reflecting unit 23 is not limited here. For example, see [link to previous section]. Figure 1 As shown, the reflection unit 23 can 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 mirror.

[0074] In this embodiment, the specific structure of the modulation unit 22 is not limited. For example, the modulation unit 22 can be a projection chip, which can modulate the light beam emitted by the light source unit 21 and generate imaging light directed towards the lens 10. The projection chip can include, but is not limited to, a DMD, LCOS, MEMS, or LCD.

[0075] In this embodiment, the specific structure of the light source unit 21 is not limited. For example, see below. Figure 1 As shown, 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 send the collimated beam to the reflection unit 23, and the reflection unit 23 reflects the collimated beam to the modulation unit 22.

[0076] It should be noted that when Figure 1 When the projection device 120 shown removes the reflection unit 23, the collimation unit 212 outputs the collimated beam to the modulation unit 22.

[0077] It should also be noted that, in addition to being used in the vehicle lighting device 100 and serving as a projection imaging and display lighting device, the projection device 120 provided in this application embodiment can also be used in devices such as projectors, head-up displays, and augmented reality (AR) glasses to serve as a projection imaging device.

[0078] The lens 10 provided in the embodiments of this application will now be described with reference to the accompanying drawings.

[0079] Figure 2 This is a schematic diagram of the structure of a lens provided in an embodiment of this application.

[0080] The lens 10 provided in this application embodiment includes at least five lenses arranged from the image side to the object side, for example... Figure 2 As shown, lens 10 may include five lenses arranged sequentially from the image side to the object side. The five lenses are designated as first lens 11, second lens 12, third lens 13, fourth lens 14, and fifth lens 15. Of course, the number of lenses may be more than five. Lens 10 satisfies the relationship: 33mm < EFL < 38mm, where EFL is the focal length of lens 10.

[0081] In this lens 10, the number of lenses with positive optical power is at least three, and the number of lenses with negative optical power is at least one, for example... Figure 2 As shown, four of the five lenses have positive optical power, and the other lens has negative optical power. Alternatively, three of the five lenses can have positive optical power, in which case the remaining two lenses have negative optical power. The lens closest to the image side of lens 10 has positive optical power. The material of the lens closest to the image side of lens 10 is plastic. At least one of the image-side and object-side surfaces of the lens closest to the image side of lens 10 is aspherical. See [link to documentation]. Figure 2 As shown, the first lens 11 is closest to the image side, that is, the first lens 11 has positive optical power, the material of the first lens 11 is plastic, and at least one of the image side and the object side of the first lens 11 is aspherical.

[0082] Because at least three lenses in lens 10 have positive optical power and at least one lens has negative optical power, the lens closest to the image side has positive optical power, and the focal length of lens 10 is between 33mm and 38mm, a projection field of view greater than 20° x 10° can be achieved with Fno ≤ 1.0, allowing lens 10 to simultaneously possess both a large aperture and a large field of view. 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, increasing the back focal length of lens 10 facilitates rear optical path arrangement, thereby improving image quality.

[0083] By setting at least one of the image side and object side of the lens closest to the image side in the lens 10 as an aspherical surface, the lens closest to the image side in the lens 10 is an aspherical lens, which can correct aberrations, thereby improving the overall performance of the lens 10 and further improving the optical effect.

[0084] During the use of the projection device 120, the individual lenses in the lens 10 are affected by the heat generated by the modulation unit 22, causing their temperatures to rise. Therefore, each lens has a temperature resistance requirement to ensure its optical performance, thereby ensuring the optical performance of the lens 10. The different distances between the individual lenses in the lens 10 and the modulation unit 22 result in different temperature resistance requirements for each lens. The lens closest to the modulation unit 22 has the highest temperature resistance requirement, while the lens farthest from the modulation unit 22 has the lowest temperature resistance requirement. In other words, the lens closest to the image side in the lens 10 has the lowest temperature resistance requirement, and the lens closest to the object side in the lens 10 has the highest temperature resistance requirement.

[0085] Therefore, it can be seen that when the lens closest to the image side in lens 10 is made of plastic, it ensures optical performance while meeting temperature resistance requirements. At the same time, because plastic lenses are low-cost, the cost of lens 10 can be reduced, thus significantly improving its economic efficiency. Furthermore, the fact that the lens closest to the image side in lens 10 has positive optical power also improves the economic efficiency of lens 10.

[0086] 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, 33.2mm, 33.5mm, 33.88mm, 33.9mm, 34mm, 34.5mm, 35mm, 35.3mm, 36mm, 37mm or 37.5mm.

[0087] In some possible implementations, lens 10 can also satisfy the relationship: 0.82 < BFL / EFL < 0.87, where BFL is the back focal length of lens 10 and EFL is the focal length of lens 10.

[0088] Correspondingly, after satisfying the relationship 0.82 < BFL / EFL < 0.87, 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.

[0089] The specific ratio of BFL to EFL is not limited here, and may include, but is not limited to, 0.821, 0.83, 0.84, 0.85, 0.8591, 0.86, 0.867 or 0.869.

[0090] In some possible implementations, the lens 10 can also satisfy the relationship: 0.8 < R1 / EFL < 3, 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.

[0091] Correspondingly, lens 10 satisfies the relationship: 0.8 < R1 / EFL < 3. 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 design of the headlights.

[0092] The specific ratio of R1 / EFL is not limited here, and can include, but is not limited to, 0.81, 0.85, 0.9, 1, 1.1, 1.3, 1.5, 1.8, 1.9, 2.0, 2.1, 2.3, 2.5, 2.6 or 2.9.

[0093] In some possible implementations, the lens 10 can also satisfy the relationship: 28mm < R1 < 107mm, where R1 is the radius of curvature of the image side of the lens closest to the image side in the lens 10.

[0094] Correspondingly, lens 10 can also satisfy the relationship: 28mm < R1 < 107mm. 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.

[0095] The specific value of R1 is not limited here, and it can be, but is not limited to, 28.1mm, 28.5mm, 29mm, 29.5mm, 30mm, 30.35mm, 30.5mm, 31mm, 35mm, 40mm, 48.6mm, 50mm, 55mm, 60mm, 65mm, 70mm, 75.69mm, 80mm, 85.6mm, 90mm, 95mm, 100mm, 105mm, 105.56mm, 106mm, 106.36mm, or -106.7mm, etc.

[0096] In some possible implementations, lens 10 can also satisfy the relationship: 0.8 < R2 / EFL < 2, where R2 is the radius of curvature of the object side of the lens closest to the object side in lens 10, and EFL is the focal length of lens 10.

[0097] Correspondingly, lens 10 satisfies the relationship: 0.8 < R² / EFL < 2. 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.

[0098] The specific ratio of R2 / EFL is not limited here, and can include, but is not limited to, 0.81, 0.85, 0.9, 1, 1.1, 1.3, 1.5, 1.57, 1.6, 1.68, 1.7, 1.71, 1.75, 1.8, 1.85, 1.9 or 1.92.

[0099] In some possible implementations, the lens 10 can also satisfy the relationship: 28mm < R2 < 72mm, where R2 is the radius of curvature of the object side of the lens closest to the object side in the lens 10.

[0100] Correspondingly, lens 10 satisfies the relationship: 28mm < R2 < 72mm. 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, effectively balancing the optical performance of lens 10 with the design of the vehicle headlight.

[0101] The specific value of R2 is not limited here, and it can be, for example, including but not limited to, 28.1mm, 28.5mm, 29.3mm, 29.5mm, 30mm, 30.35mm, 30.5mm, 31mm, 35mm, 40mm, 48.65mm, 50mm, 55.9mm, 60mm, 65mm, 70mm, 71mm, 71.315mm, or 71.6mm.

[0102] In some possible implementations, the image-side surface of the lens closest to the image side in lens 10 can be aspherical, for example, see [link to relevant documentation]. Figure 2 As shown, the image side of the first lens 11 is aspherical, making the first lens 11 an aspherical mirror.

[0103] By setting the image side of the lens closest to the image side in lens 10 as an aspherical surface, aberrations can be corrected, further improving the optical effect.

[0104] It should be noted that, in addition to the image side being aspherical, in some embodiments, the object side of the lens closest to the image side in the lens 10 can also be aspherical, thus making the lens closest to the image side in the lens 10 an aspherical lens. Alternatively, in other embodiments, both the object side and the image side of the lens closest to the image side in the lens 10 are aspherical, thus making the lens closest to the image side in the lens 10 an aspherical lens.

[0105] In some possible implementations, all lens elements in lens 10 except for the one closest to the image side are made of optical glass, for example, see [link to relevant documentation]. Figure 2 As shown, the second lens 12, the third lens 13, the fourth lens 14 and the fifth lens 15 are all made of optical glass.

[0106] During the operation of the projection device 120, the modulation unit 22 generates heat, which is transferred to the lens 10, causing the temperature of the lenses in the lens 10 to rise. At this time, the lens closer to the modulation unit 22 has a higher temperature. Therefore, making the remaining lenses in the lens 10, except for the lens closest to the image side, of optical glass can better meet the temperature resistance requirements and help to further improve optical performance.

[0107] It should be noted that, except for the lens closest to the image side, the other lenses in lens 10 are made of optical glass. In some embodiments, lens 10 may also include a first lens group and a second lens group arranged from the image side to the object side, with the first lens group closest to the image side and the second lens group closest to the object side. Both the first and second lens groups include multiple lenses. The second lens group includes the lens closest to the object side, and all lenses in the second lens group are made of optical glass. The second lens group may have at least three lenses.

[0108] In some possible implementations, the lens closest to the object side in lens 10 can have positive optical power, for example... Figure 2 As shown, the fifth lens 15, which is closest to the object side, has positive optical power. Of course, the fifth lens 15 can also have negative optical power.

[0109] 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.

[0110] In some possible implementations, all the lenses in lens 10 except for the one closest to the image side can be spherical lenses, for example... Figure 2As shown, the second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15 are all spherical lenses.

[0111] Correspondingly, by setting the remaining lenses in lens 10, except for the one closest to the image side, as spherical lenses, the processing difficulty of these lenses can be reduced, and the image quality can be improved.

[0112] See also some possible implementations. Figure 2 As shown, the lens 10 may also include an aperture stop 16. The aperture stop 16 may be positioned between two adjacent lens elements in the lens 10, for example... Figure 2 As shown, the aperture stop 16 can be positioned between the third lens 13 and the fourth lens 14. Of course, the aperture stop 16 can also be positioned in other locations.

[0113] See also some possible implementations. Figure 2 As shown, the lens 10 may also include a cover glass 17. The cover glass 17 is disposed between the lens closest to the object side of the lens 10 and the modulation unit 22, and the cover glass 17 is used to protect the modulation unit 22.

[0114] 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.

[0115] It should be noted that the lens 10 may include either a cover glass 17 or a filter, or both.

[0116] The structure and performance of the projection device 120 provided in this application will be described below with reference to specific embodiments.

[0117] Figure 3 This is a schematic diagram of the structure of the first projection device provided in Embodiment 1 of this application.

[0118] See Figure 3 As shown, 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, an aperture 16, a fourth lens 14, a fifth lens 15, and a cover glass 17, arranged sequentially from the image side to the object side. The first lens 11 is closest to the image side, the fifth lens 15 is also 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 is a projection chip, which may be a DMD or LCOS.

[0119] 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|=7.60.

[0120] The second lens element 12 has positive 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|=7.47.

[0121] The third lens element 13 has negative 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|=-1.58.

[0122] The fourth lens element 14 has positive 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|=1.49.

[0123] 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|=1.46.

[0124] The lens closest to the image side in lens 10 is the first lens element 11, which is an aspherical lens. Therefore, the object side surface of the first lens element 11 is aspherical. The radius of curvature R1 of the image side surface of the first lens element 11 is 31.25 mm, which is greater than 28 mm and less than 107 mm, satisfying the requirements. The ratio of the radius of curvature R1 of the image side surface of the first lens element 11 to the focal length EFL of lens 10, R1 / EFL, is 0.889, which is greater than 0.8 and less than 3, satisfying the requirements.

[0125] The lens closest to the object side in lens 10 is the fifth lens element 15. The radius of curvature of the object side surface of the fifth lens element 15, R2, is 36.1 mm, which is greater than 28 mm and less than 72 mm, thus meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of the fifth lens element 15 to the focal length EFL of lens 10, R2 / EFL, is 1.026, which is greater than 0.8 and less than 2, thus meeting the requirements.

[0126] The ratio of the back focal length BFL of lens 10 to the focal length EFL of lens 10, BFL / EFL = 0.8396, is greater than 0.82 and less than 0.87, which meets the requirements.

[0127] Lens 10 has a focal length EFL of 35.18mm, which is greater than 33mm and less than 38mm, thus meeting the requirements.

[0128] Table 1 shows the optical parameters of each optical element in the projection device 120 provided in this embodiment.

[0129] Face number Surface type R(mm) TH(mm) Nd Vd OBJ spherical endless 10000 S1 spherical 31.254 6.131 1.59 29.9 S2 spherical 36.097 15.835 S3 spherical -33.698 10.004 1.80 46.6 S4 spherical -32.964 3.06 S5 spherical -108.461 1.995 1.92 18.9 S6 spherical 102.114 2.476 S7 spherical Infinity 0.000 S8 spherical 148.484 8.284 1.73 54.7 S9 spherical -50.902 0.300 1.79 47.5 S10 spherical 34.373 9.452 S11 spherical 193.841 28.128 1.523 58.6 S12 spherical Infinity 1.100 S13 spherical Infinity 0.310 ImgH spherical Infinity 0

[0130] Wherein, 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 surface (object surface), and ImgH is the imaging surface.

[0131] 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 in the direction of the optical axis, Nd is the refractive index of each optical element when d-line is irradiated, and Vd is the Abbe number of the optical element.

[0132] Table 2 shows the optical parameters of the lens 10 provided in this embodiment.

[0133] f1(mm) 267.362 EFL (mm) 35.18 f2 (mm) 262.855 TTL(mm) 87.08 f3 (mm) -55.611 Fno 0.90 f4 (mm) 52.551 BFL (mm) 29.54 f5 (mm) 51.255 R1(mm) 31.25 R2 (mm) 36.1 FOV (°) 22.3

[0134] Wherein, EFL is the focal length of lens 10, FOV is the maximum field of view 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, 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, and f5 is the focal length of the fifth lens 15.

[0135] Figure 4 for Figure 3 The spherical chromatic aberration diagram of the lens in the image. Figure 4 In the diagram, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberrations along the axial direction, with units of millimeters. Figure 4 In the diagram, the three curves correspond to the axial aberration curves of light with wavelengths of 625nm, 550nm, and 455nm after passing through the lens 10 in this embodiment. From... Figure 4 As can be seen, in this embodiment, the axial aberration is controlled within a very small range, resulting in good correction.

[0136] Figure 5 for Figure 3 The image in the scene is like an ending sequence. Figure 6 for Figure 3 The distortion diagram of the lens in the image. Figure 5In the diagram, 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. Figure 6 In the image, the solid line represents the distortion value of light with a center wavelength of 525nm passing through the lens 10 of this embodiment. In this embodiment, combined with... Figure 5 and Figure 6 It can be seen that the lens 10 provided in this embodiment controls field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0137] Figure 7 This is a schematic diagram of the structure of the second projection device provided in Embodiment 2 of this application.

[0138] See Figure 7 As shown, 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, an aperture 16, a fourth lens 14, a fifth lens 15, and a cover glass 17, arranged sequentially from the image side to the object side. The first lens 11 is closest to the image side, the fifth lens 15 is also 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 is a projection chip, which may be a DMD or LCOS.

[0139] 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|=4.78.

[0140] The second lens element 12 has positive 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|=9.94.

[0141] The third lens element 13 has negative 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|=-2.33.

[0142] The fourth lens element 14 has positive 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|=0.77.

[0143] The fifth lens element 15 has negative optical power. 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|=-7.07.

[0144] The lens closest to the image side in lens 10 is the first lens element 11, which is an aspherical lens. Therefore, the object side surface of the first lens element 11 is aspherical. The radius of curvature R1 of the image side surface of the first lens element 11 is 39.78 mm, which is greater than 28 mm and less than 107 mm, satisfying the requirements. The ratio of the radius of curvature R1 of the image side surface of the first lens element 11 to the focal length EFL of lens 10, R1 / EFL, is 1.13, which is greater than 0.8 and less than 3, satisfying the requirements.

[0145] The lens closest to the object side in lens 10 is the fifth lens element 15. The radius of curvature R2 of the object side surface of the fifth lens element 15 is 62.38 mm, which is greater than 28 mm and less than 72 mm, thus meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of the fifth lens element 15 to the focal length EFL of lens 10, R2 / EFL, is 1.77, which is greater than 0.8 and less than 2, thus meeting the requirements.

[0146] The ratio of the back focal length BFL of lens 10 to the focal length EFL of lens 10, BFL / EFL = 0.8389, is greater than 0.82 and less than 0.87, which meets the requirements.

[0147] Lens 10 has a focal length EFL of 35.2mm, which is greater than 33mm and less than 38mm, thus meeting the requirements.

[0148] Table 3 shows the optical parameters of each optical element in the projection device 120 provided in this embodiment 2.

[0149]

[0150]

[0151] Wherein, 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 surface (object surface), and ImgH is the imaging surface.

[0152] 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 in the direction of the optical axis, Nd is the refractive index of each optical element when d-line is irradiated, and Vd is the Abbe number of the optical element.

[0153] Table 4 shows the optical parameters of the lens 10 provided in this embodiment 2.

[0154] f1(mm) 168.650 EFL (mm) 35.2 f2 (mm) 349.590 TTL(mm) 84.52 f3 (mm) -81.919 Fno 0.90 f4 (mm) 27.111 BFL (mm) 29.53 f5 (mm) -248.505 R1(mm) 39.78 R2 (mm) 62.38 FOV (°) 22.3

[0155] Wherein, EFL is the focal length of lens 10, FOV is the maximum field of view 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, 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, and f5 is the focal length of the fifth lens 15.

[0156] Figure 8 for Figure 7 The spherical chromatic aberration diagram of the lens in the image. Figure 8 In the diagram, the vertical axis represents the normalized pupil coordinates, and the horizontal axis represents the aberrations along the axial direction, with units of millimeters. Figure 8 In the diagram, the three curves correspond to the axial aberration curves of light with wavelengths of 625nm, 550nm, and 455nm after passing through the lens 10 in this embodiment. From... Figure 8 As can be seen, in this embodiment, the axial aberration is controlled within a very small range, resulting in good correction.

[0157] Figure 9 for Figure 8 The image in the scene is like an ending sequence. Figure 10 for Figure 8 The distortion diagram of the lens in the image. Figure 9 In the diagram, 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. Figure 10 In the image, the solid line represents the distortion value of light with a center wavelength of 525nm passing through the lens 10 of this embodiment. In this embodiment, combined with... Figure 9 and Figure 10 It can be seen that the lens 10 provided in this embodiment controls field curvature and distortion within the corresponding range, which can meet the usage requirements.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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 by comprising: The lens includes at least five lenses arranged from an image side to an object side; 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; The lens closest to the image side in the lens has positive refractive power, the lens closest to the image side in the lens is made of plastic, and at least one of the image side surface and the object side surface of the lens closest to the image side in the lens is aspherical; The lens satisfies the relationship: 33mm < EFL < 38mm, where the EFL is the focal length of the lens.

2. The lens according to claim 1, characterized in that, The lens satisfies the relationship: 0.82 < BFL / EFL < 0.87, where the BFL is the back focal length of the lens, and the 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: 0.8 < R1 / EFL < 3, where the R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens, and the 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: 28mm < R1 < 107mm, where the R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens.

5. The lens according to any one of claims 1 to 4, characterized in that, The lens satisfies the relationship: 0.8 < R2 / EFL < 2, where the R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens, and the 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 relationship: 28mm < R2 < 72mm, where the R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens.

7. The lens according to any one of claims 1 to 6, characterized in that The image side surface of the lens closest to the image side in the lens is aspherical.

8. The lens according to any one of claims 1 to 7, characterized in that The lenses other than the lens closest to the image side in the lens are made of optical glass.

9. A projection apparatus, characterized by comprising: The projection device includes a display unit and a lens as claimed in any one of claims 1 to 8, the display unit being configured to emit imaging light to the lens.

10. The projection apparatus according to claim 9, wherein, The display unit includes a light source unit and a modulation unit; The modulation unit is configured to modulate a light beam emitted by the light source unit to generate the imaging light, and to emit the imaging light to the lens.

11. The projection apparatus according to claim 10, wherein, The display unit further includes a reflection unit configured to reflect the light beam emitted by the light source unit to the modulation unit.

12. A vehicle lamp device characterized by comprising: The projection device includes a housing and a projection device as claimed in any one of claims 9 to 11, at least a part of the projection device being disposed inside the housing.

13. A vehicle, characterized by The vehicle lamp device includes the vehicle lamp device as claimed in claim 12.

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