Lens device, projection device, vehicle lamp device and vehicle

Abstract

Embodiments of the present application relate to the technical field of optics, and provide a lens device, a projection device, a vehicle lamp device and a vehicle. The lens device comprises at least five lenses arranged from an image side to an object side. The image side surface of the lens in the lens device that is closest to the image side a concave surface. The lens device comprises at least three lenses having positive focal power, and comprises at least one lens having negative focal power. When there is one lens having negative focal power, the lens having negative focal power is arranged between the lens in the lens device that is closest to the image side and the lens in the lens device that is closest to the object side. The lens device provided by the embodiments of the present application can realize a large field-of-view angle under the condition that Fno is smaller than or equal to 1.0, so that the lens device can have the characteristic of having both a large aperture and a large field-of-view angle.

Description

Lenses, projection devices, lighting devices and vehicles

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on December 14, 2023, with application number 202311723350.6 and application name “Lens, projection device, car light device and vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of optical technology, and in particular to a lens, a projection device, a vehicle light device, and a vehicle. Background Art

[0003] With the development of smart car technology, headlights are required to not only provide traditional lighting functions but also project patterns to meet increasing demands for welcoming guests, information exchange, and autonomous driving. Therefore, to meet these growing demands, the optical requirements for pattern-projecting headlights are becoming increasingly stringent. For example, headlights are required to have a wide projectable field of view (FOV). The FOV is an important indicator of the amount of projected information; a wider FOV indicates a greater amount of projected information. However, lenses used in headlights cannot simultaneously offer both a large aperture and a wide FOV. Summary of the Invention

[0004] The embodiments of the present application provide a lens, a projection device, a vehicle lamp device, and a vehicle, which can enable the lens to have a large aperture and a large field of view.

[0005] In a first aspect, the present application provides a lens comprising at least five lens elements arranged from the image side to the object side. The image side surface of the lens element closest to the image side is concave, the number of lens elements with positive optical power in the lens element is at least three, and the number of lens elements with negative optical power in the lens element is at least one. When there is only one lens element with negative optical power, the lens element with negative optical power is positioned between the lens element closest to the image side and the lens element closest to the object side.

[0006] The lens provided in the embodiments of the present application is composed of at least five lens elements, at least three of which have positive focal power, and at least one of which has negative focal power. The image-side surface of the lens element closest to the image side is concave, which can achieve a large field of view angle under the condition that Fno is less than or equal to 1.0. Therefore, the lens can simultaneously have the characteristics of a large aperture and a large field of view angle, thereby meeting projection requirements. In addition, while achieving a large aperture and a large field of view angle, the lens can also ensure a sufficiently long back focal length, which is conducive to the configuration of the rear optical path.

[0007] When there is only one lens element with negative power, and the lens element is positioned between the lens element closest to the image side and the lens element closest to the object side, the lens can simultaneously achieve both a large aperture and a wide field of view. Alternatively, when there are at least two lens elements with negative power, and the lens element closest to the object side and / or image side has negative power, the lens can also achieve both a large aperture and a wide field of view.

[0008] In a possible implementation, the lens satisfies the relationship: 0.8<BFL / EFL<0.9, where BFL is the back focal length of the lens, and EFL is the focal length of the lens.

[0009] The lens provided in the embodiment of the present application satisfies the relationship: 0.8 < BFL / EFL < 0.9, which can prevent the lens's optical path from being too long or too short, facilitating the design and rear-end optical path configuration. Furthermore, it can ensure that the lens has both a large aperture and a wide field of view.

[0010] In a possible implementation, the lens satisfies the relationship: 33 mm < EFL < 38 mm, where EFL is the focal length of the lens.

[0011] The focal length of the lens provided in the embodiment of the present application is greater than 33 mm and less than 38 mm. It can achieve a field of view greater than 20°X10° while achieving a large aperture, where 20° refers to the field of view of the lens in the horizontal direction and 10° refers to the field of view of the lens in the vertical direction.

[0012] In a possible implementation, the lens satisfies the relationship: -4<R1 / EFL<-2, where R1 is the curvature radius of the image side surface of the lens element closest to the image side in the lens, and EFL is the focal length of the lens.

[0013] The lens provided in the embodiment of the present application satisfies the relationship: -4<R1 / EFL<-2. This can reduce the manufacturing difficulty of the lens closest to the image side in the lens while achieving a large aperture and a large field of view, improve the yield rate, and help improve economic efficiency. In addition, it can also facilitate the correction of aberrations. In addition, it can also prevent the image side of the lens closest to the image side of the lens from being too protruding or too flat. In particular, if the image side of the lens closest to the image side is too protruding, it may cause the lens to interfere with other components, and if the image side of the lens closest to the image side is too flat, it may affect the shape of the headlights.

[0014] In a possible implementation, the lens satisfies the relationship: -152 mm < R1 < -99 mm, where R1 is the radius of curvature of the image side of the lens element closest to the image side in the lens.

[0015] The lens provided in the embodiment of the present application satisfies the relationship: -152mm<R1<-99mm. This reduces the manufacturing difficulty of the lens closest to the image side while achieving both a large aperture and a wide field of view, improving yield and contributing to improved economic efficiency. Furthermore, it facilitates the correction of aberrations. Furthermore, it prevents the image side of the lens closest to the image side from being too protruding or too flat, effectively balancing the optical performance of the lens and the shape of the headlight.

[0016] In a possible implementation, the lens satisfies the relationship: -10<R2 / EFL<10, where R2 is the radius of curvature of the object side of the lens element closest to the object side in the lens, and EFL is the focal length of the lens.

[0017] The lens provided in the embodiment of the present application satisfies the relationship: -10<R2 / EFL<10. Under the premise of achieving a large aperture and a large field of view at the same time, it can reduce the manufacturing difficulty of the lens closest to the object side of the lens, improve the yield rate, and help improve economic efficiency. In addition, it can also prevent the object side surface of the lens closest to the object side of the lens from being too protruding or too concave. Among them, if the object side surface of the lens closest to the object side is too protruding, it will interfere with the other optical elements, or compress the optical space between the lens and the projection chip, or cause damage to the lens close to the object side. If the object side surface of the lens closest to the object side is too concave, it will be detrimental to aberration correction.

[0018] In a possible implementation, the lens satisfies the relationship: -380 mm < R2 < 380 mm, where R2 is the radius of curvature of the object side surface of the lens element closest to the object side in the lens.

[0019] The lens provided in this embodiment satisfies the relationship: -380mm < R2 < 380mm. While simultaneously achieving a large aperture and a wide field of view, it also reduces the manufacturing difficulty of the lens element closest to the object side, improving yield and boosting cost efficiency. Furthermore, it prevents the object side of the lens element closest to the object side from being too protruding or too concave, effectively balancing the optical performance of the lens and the design of the headlight.

[0020] In one possible implementation, the lens element closest to the image side of the lens has positive refractive power.

[0021] The lens provided in the embodiment of the present application can improve the economy of the lens while achieving a large aperture and a large field of view by setting the lens closest to the image side to a lens with positive optical power.

[0022] In one possible implementation, the lens element closest to the object side of the lens has positive refractive power.

[0023] The lens provided in the embodiment of the present application can increase the amount of light entering the lens by setting the lens closest to the object side to have a positive optical power, thereby improving optical performance. In addition, it can also improve the cost-effectiveness of the lens.

[0024] In the first aspect of the present application, two projection devices are provided, comprising a display unit and a lens as described in any one of the first aspects, wherein the display unit is configured to emit imaging light toward the lens.

[0025] In a possible implementation, the display unit includes a light source unit and a modulation unit, wherein the modulation unit is configured to modulate the light beam emitted by the light source unit to generate imaging light, and emit the imaging light toward the lens.

[0026] In a possible implementation, the display unit further includes a reflection unit, and the reflection unit is configured to reflect the light beam emitted by the light source unit to the modulation unit.

[0027] A third aspect of the present application provides a vehicle lamp device, comprising a housing and a projection device as described in any one of the second aspects, wherein at least a portion of the projection device is disposed inside the housing.

[0028] A fourth aspect of the present application is a vehicle comprising the vehicle light device according to the third aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic structural diagram of a vehicle lamp device provided in an embodiment of the present application;

[0030] FIG2 is a schematic structural diagram of a lens provided in an embodiment of the present application;

[0031] FIG3 is a schematic structural diagram of a first projection device provided in Example 1 of the present application;

[0032] FIG4 is a diagram of spherical chromatic aberration of the lens in FIG3 ;

[0033] FIG5 is a diagram of astigmatism field curvature of the lens in FIG3 ;

[0034] FIG6 is a distortion diagram of the lens in FIG3 ;

[0035] FIG7 is a schematic structural diagram of a second projection device provided in Example 2 of the present application;

[0036] FIG8 is a diagram of spherical chromatic aberration of the lens in FIG7 ;

[0037] FIG9 is a diagram of astigmatism field curvature of the lens in FIG8 ;

[0038] FIG10 is a distortion diagram of the lens in FIG8 ;

[0039] FIG11 is a schematic structural diagram of a third projection device provided in Example 3 of the present application;

[0040] FIG12 is a diagram of spherical chromatic aberration of the lens in FIG11 ;

[0041] FIG13 is a diagram of astigmatism field curvature of the lens in FIG11 ;

[0042] FIG. 14 is a distortion diagram of the lens 10 in FIG. 11 .

[0043] Explanation of the accompanying drawings: 100, vehicle lamp device; 110, housing; 120, projection device; 10, lens; 11, first lens; 12, second lens; 13, third lens; 14, fourth lens; 15, fifth lens; 16, aperture; 17, cover glass; 20, display unit; 21, light source unit; 211, light source; 212, collimation unit; 22, modulation unit; 23, reflection unit. DETAILED DESCRIPTION

[0044] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0045] To facilitate understanding, the relevant technical terms involved in the embodiments of this application are first explained and illustrated.

[0046] 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 an infinitely distant scene forms a clear image on the focal plane through a lens or lens group.

[0047] The image side, with the lens as the boundary, the side where the image is located is the image side, and the side of the lens facing the image side is the image side of the lens.

[0048] 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 surface.

[0049] Total track length (TTL) refers to the total length from the vertex of the first lens element located near the object side of the lens to the imaging surface of the lens, also known as the total optical length.

[0050] The back focal length (BFL) is defined as the distance from the lens element closest to the imaging surface to the modulation unit.

[0051] Optical power represents the ability of a lens to refract an incident parallel light beam.

[0052] Positive optical power means that the lens has a positive focal length and has the effect of converging light.

[0053] Negative optical power means that the lens has a negative focal length and has the effect of diverging light.

[0054] The aperture is a device used to control the amount of light that passes through the lens and enters the interior of an electronic device. It is usually located inside the lens and is expressed in F# (F-number).

[0055] The aperture number F# is a relative value obtained by dividing the focal length of the lens by the diameter of the lens (the inverse of the relative aperture). The smaller the aperture number F#, the more light enters in the same unit time.

[0056] Cover glass (CG) is used to protect the projection chip.

[0057] The modulation unit is used to modulate the light beam emitted by the light source to generate image light that forms an image.

[0058] Digital micromirror devices (DMD) are used to reflect light to form images.

[0059] Liquid crystal on silicon (LCOS), used to reflect light.

[0060] 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 before and after passing through a lens. This is called positional chromatic aberration or axial chromatic aberration. This is because the lens positions images of different wavelengths of light differently, resulting in images of different colors not completely overlapping on the imaging plane. This causes the complex colors of light to scatter and form dispersion.

[0061] Distortion, also known as distortion, refers to the degree to which the image formed by an optical system is distorted relative to the object itself. Distortion is caused by aperture aberration. The height at which the chief rays of light from different fields of view intersect the Gaussian image plane after passing through the optical system is not equal to the ideal image height. The difference between the two is the distortion. Therefore, distortion only changes the image position of off-axis object points on the ideal plane, distorting the image shape but not affecting image clarity.

[0062] With the development of smart car technology, headlights are required to not only provide traditional lighting functions but also project patterns to meet the growing demands for welcoming guests, information exchange, and autonomous driving. Therefore, to meet these increasing demands, the optical requirements for headlights capable of projecting patterns will become increasingly stringent. For example, headlights are required to have a wide projectable field of view (FOV). The FOV is an important indicator of the amount of projected information; the larger the FOV, the greater the amount of information that can be projected. However, lenses used in headlights cannot simultaneously achieve a large aperture and a wide FOV. Therefore, how to achieve both a large aperture and a wide FOV has become a pressing issue.

[0063] In view of this, an embodiment of the present application provides a lens 10, a projection device 120, a headlight device 100 and a vehicle. The lens 10 can simultaneously have the characteristics of a large aperture and a large field of view, and can improve the projection range and brightness to meet usage requirements.

[0064] The vehicles provided in the embodiments of the present application may include, but are not limited to, cars, trucks, motorcycles, buses, boats, airplanes, helicopters, lawn mowers, recreational vehicles, amusement park vehicles, construction equipment, trams, golf carts, trains, or carts. In the embodiments of the present application, a bridge vehicle is used as an example of the above-mentioned vehicles for illustration. The vehicles may include a headlight device 100 that can emit light at night to ensure driving safety.

[0065] The vehicle lighting device 100 provided in the embodiment of the present application may include but is not limited to pixel display lights, near-field welcome lights, pedestrian or interactive lights, car headlights, etc. For example, in the embodiment of the present application, a car headlight is taken as an example of the above-mentioned vehicle lighting device 100. The vehicle lighting device 100 can play the role of projection imaging and display lighting, such as lighting at night.

[0066] Figure 1 is a schematic diagram of the structure of a vehicle lighting device provided in an embodiment of the present application. As shown in Figure 1 , vehicle lighting device 100 may include a housing 110 and a projection device 120. Projection device 120 is at least partially disposed within housing 110. For example, as shown in Figure 1 , projection device 120 is disposed within housing 110. Alternatively, projection device 120 may be partially disposed within housing 110 and partially disposed outside of housing 110. Projection device 120 is used for projecting images and displaying illumination.

[0067] 1 , the projection device 120 may include a display unit 20 and a lens 10. The display unit 20 is configured to emit imaging light to the lens 10. The lens 10 may emit the imaging light to the outside of the housing 110 to form an image outside the housing 110 or to provide lighting.

[0068] 1 , the display unit 20 includes a light source unit 21 and a modulation unit 22 . The modulation unit 22 is configured to modulate the light beam emitted by the light source unit 21 to generate imaging light, and emit the imaging light toward the lens 10 .

[0069] The specific structure of the modulation unit 22 is not limited here. For example, the modulation unit 22 can be a projection chip that modulates the light beam emitted by the light source unit 21 and generates imaging light directed toward the lens 10. The projection chip can include, but is not limited to, a DMD, LCOS, MEMS, or LCD.

[0070] In some possible implementations, as shown in FIG1 , the light source unit 21 may further include a light source 211 and a collimating unit 212 . The collimating unit 212 is configured to collimate the light emitted by the light source 211 and transmit the collimated light beam to the reflecting unit 23 , which then reflects the collimated light beam to the modulating unit 22 .

[0071] In some possible implementations, referring to FIG. 1 , the display unit 20 may further include a reflection unit 23 , and the reflection unit 23 is configured to reflect the light beam emitted by the light source unit 21 to the modulation unit 22 .

[0072] There is no limitation on the specific structure of the reflection unit 23. For example, referring to FIG1 , the reflection unit 23 may be a curved mirror, and the light emitted by the light source unit 21 is reflected to the modulation unit 22 by the curved surface of the curved mirror.

[0073] It should be noted that the projection device 120 provided in the embodiment of the present application can be used in devices such as projectors, head-up display devices, augmented reality (AR) glasses, etc., in addition to being used for projection imaging and display lighting of the vehicle lamp device 100. It can also be used to perform projection imaging.

[0074] The lens 10 provided in the embodiment of the present application is described below with reference to the accompanying drawings.

[0075] FIG2 is a schematic structural diagram of a lens provided in an embodiment of the present application.

[0076] The lens 10 provided in an embodiment of the present application includes at least five lenses arranged from the image side to the object side. For example, as shown in FIG2 , the lens 10 may include five lenses arranged in sequence from the image side to the object side, and the five lenses are respectively a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, and a fifth lens 15. Of course, the number of lenses may be more than five. As shown in FIG2 , the image side surface of the lens closest to the image side in the lens 10 is concave, that is, the image side surface of the first lens 11 is concave. The number of lenses with positive optical power in the lens 10 is at least three, and the number of lenses with negative optical power in the lens 10 is at least one. For example, as shown in FIG2 , four of the five lenses have positive optical power and one lens has negative optical power. Of course, the number of lenses with positive optical power in the five lenses may also be three, and the number of lenses with negative optical power in the five lenses may also be two. When there is only one lens element with negative power, the lens element with negative power is positioned between the lens element closest to the image side and the lens element closest to the object side in lens 10. For example, as shown in FIG2 , lens 10 may include a first lens element 11 with positive power, a second lens element 12 with positive power, a third lens element 13 with negative power, a fourth lens element 14 with positive power, and a fifth lens element 15 with positive power, arranged from the image side to the object side, with the first lens element 11 closest to the image side and the fifth lens element 15 closest to the object side. When there are multiple lens elements with negative power, the positions of the lens elements with negative power are not limited.

[0077] Lens 10 is composed of at least five lens elements, at least three of which have positive focal power, and at least one lens element in lens 10 has negative focal power. The image-side surface of the lens element closest to the image side in lens 10 is concave, enabling a wide field of view with an Fno of less than or equal to 1.0. Thus, lens 10 simultaneously possesses the characteristics of a large aperture and a wide field of view, thereby meeting projection requirements. Furthermore, while achieving both a large aperture and a wide field of view, lens 10 can also maintain a sufficiently long back focal length, facilitating the configuration of the rear optical path.

[0078] When there is one lens element with negative power, the lens element with negative power is positioned between the lens element closest to the image side and the lens element closest to the object side in lens 10, thereby ensuring that lens 10 simultaneously possesses the characteristics of a large aperture and a wide field of view. When there are at least two lens elements with negative power, the lens element closest to the object side and / or the image side in lens 10 may also have negative power, thereby also ensuring that lens 10 simultaneously possesses the characteristics of a large aperture and a wide field of view.

[0079] In some possible implementations, the lens 10 may further satisfy the relationship: 0.8<BFL / EFL<0.9, where BFL is the back focal length of the lens 10 , and EFL is the focal length of the lens 10 .

[0080] Accordingly, when the lens 10 satisfies the relationship: 0.8 < BFL / EFL < 0.9, it can prevent the optical path of the lens 10 from being too long or too short, which is beneficial for the design and the configuration of the rear optical path. In addition, it can ensure that the lens 10 has the characteristics of a large aperture and a large field of view.

[0081] There is no limitation on the specific ratio of BFL / EFL, and it may include but is not limited to 0.81, 0.82, 0.83, 0.84, 0.85, 0.8591, 0.86, 0.87, 0.88 or 0.89.

[0082] In some possible implementations, the lens 10 may further satisfy the relationship: 33 mm < EFL < 38 mm, where EFL is the focal length of the lens 10 .

[0083] Accordingly, the focal length of the lens 10 is greater than 33 mm and less than 38 mm, and can achieve a field of view greater than 20°X10° while achieving a large aperture, where 20° refers to the field of view of the lens 10 in the horizontal direction, and 10° refers to the field of view of the lens 10 in the vertical direction.

[0084] There is no limitation on the specific focal length of the lens 10 , and the focal length may include, but is not limited to, 33.5 mm, 33.88 mm, 33.9 mm, 34 mm, 34.5 mm, 35 mm, 35.3 mm, 36 mm, 37 mm, or 37.5 mm.

[0085] In some possible implementations, the lens 10 may also satisfy the relationship: -4<R1 / EFL<-2, where R1 is the curvature radius of the image side surface of the lens element closest to the image side in the lens 10, and EFL is the focal length of the lens 10.

[0086] Accordingly, lens 10 satisfies the relationship: -4<R1 / EFL<-2. This can reduce the manufacturing difficulty of the lens closest to the image side in lens 10 while achieving both a large aperture and a wide field of view, improve the yield rate, and thus contribute to improved economic efficiency. Furthermore, this can facilitate the correction of aberrations. Furthermore, it can also prevent the image side of the lens closest to the image side in lens 10 from being too protruding or too flat. If the image side of the lens closest to the image side is too protruding, it may cause interference with other components, while if the image side of the lens closest to the image side is too flat, it may affect the shape of the headlights.

[0087] There is no limitation on the specific ratio of R1 / EFL, and it may include but is not limited to -2.1, -2.5, -3, -3.5, -3.6, -3.8, -3.9 or -3.985.

[0088] In some possible implementations, the lens 10 may also satisfy the relationship: -152 mm < R1 < -99 mm, where R1 is the curvature radius of the image side surface of the lens element closest to the image side in the lens 10 .

[0089] Accordingly, lens 10 can also satisfy the relationship: -152mm < R1 < -99mm. This reduces the manufacturing difficulty of the lens element closest to the image side of lens 10, improves yield, and contributes to improved economic efficiency, while simultaneously achieving a large aperture and a wide field of view. Furthermore, it facilitates aberration correction. Furthermore, it prevents the image side of the lens element closest to the image side of lens 10 from being too protruding or too flat, effectively balancing the optical performance of lens 10 and the design of the headlight.

[0090] There is no limitation on the specific value of R1. For example, it may include but is not limited to -99.5mm, -100mm, -105mm, -110mm, -115mm, -120mm, -121mm, -125mm, -130mm, -135mm, -140mm, -145mm, -150mm, -151mm or -151.95mm, etc.

[0091] In some possible implementations, the lens 10 may further satisfy the relationship: -10<R2 / EFL<10, where R2 is the curvature radius of the object side surface of the lens element closest to the object side in the lens 10 , and EFL is the focal length of the lens 10 .

[0092] Accordingly, the lens 10 satisfies the relationship: -10<R2 / EFL<10. This can reduce the manufacturing difficulty of the lens closest to the object side in the lens 10 while achieving a large aperture and a large field of view, improve the yield rate, and help improve economic efficiency. In addition, it can also prevent the object side surface of the lens closest to the object side in the lens 10 from being too protruding or too concave. Among them, if the object side surface of the lens closest to the object side is too protruding, it will interfere with the other optical elements, or compress the optical space between the lens 10 and the projection chip, or cause damage to the lens closest to the object side. If the object side surface of the lens closest to the object side is too concave, it will be detrimental to aberration correction.

[0093] There is no limitation on the specific ratio of R2 / EFL, and it may include, but is not limited to, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 1.85, 1.897, 1.9, 1.95, 2, 2.5, 5.987, 2.6, 3, 3.5, 3.6, 4, 4.5, 5, 5.1, 5.159, 5.19, 5.195, 6, 7, 8, 9, 9.1, 9.22 or 9.984, etc.

[0094] In some possible implementations, the lens 10 may further satisfy the relationship: -380 mm < R2 < 380 mm, where R2 is the curvature radius of the object side surface of the lens element closest to the object side in the lens 10 .

[0095] Accordingly, lens 10 satisfies the relationship: -380mm < R2 < 380mm. This allows for both a large aperture and a wide field of view while reducing the manufacturing difficulty of the lens element closest to the object side of lens 10, improving yield and boosting cost efficiency. Furthermore, this prevents the object side of the lens element closest to the object side of lens 10 from being too protruding or too concave, effectively balancing the optical performance of lens 10 and the design of the headlight.

[0096] There is no limitation on the specific value of R2, and it may include, but is not limited to, -375mm, -370mm, -350mm, -300mm, -250mm, -200mm, -150mm, -100mm, 0, 10mm, 50mm, 73.5mm, 76.98mm, 79mm, 80mm, 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm, 121mm, 125mm, 129mm, 130mm, 140mm, 150mm, 160mm, 170mm, 180mm, 181mm, 182mm, 183mm, 184mm, 184.954mm, 200mm, 250mm, 300mm, 310mm, 340mm, 350mm, 355mm, 359mm, 360mm, 370mm or 375mm, etc.

[0097] In some possible implementations, the lens element closest to the image side in the lens 10 may have positive optical power. For example, as shown in FIG2 , the first lens element 11 closest to the image side has positive optical power. Of course, the first lens element 11 may also have negative optical power.

[0098] Accordingly, by setting the lens closest to the image side to a lens with positive refractive power, it is possible to achieve a large aperture and a large field of view at the same time, which is beneficial to improving the economy of the lens 10.

[0099] In some possible implementations, the lens element closest to the object side in the lens 10 may have positive optical power. For example, as shown in FIG. 2 , the fifth lens element 15 closest to the object side has positive optical power. Of course, the fifth lens element 15 may also have negative optical power.

[0100] Accordingly, by setting the lens closest to the object side to a lens with positive refractive power, the amount of light entering the lens 10 can be increased, thereby improving the optical performance. In addition, the cost-effectiveness of the lens 10 can also be improved.

[0101] In some possible implementations, at least one lens may be a spherical lens. For example, as shown in FIG2 , all five lenses in the lens 10 may be spherical lenses. Of course, the number of spherical lenses may be less than five.

[0102] Accordingly, the more spherical mirrors the lens 10 provided in the embodiment of the present application uses, the greater the reduction in the difficulty of manufacturing the lens 10, which is beneficial for improving the yield rate and also improving the imaging quality.

[0103] In some possible implementations, as shown in FIG2 , the lens 10 may further include an aperture 16. The aperture 16 may be disposed between two adjacent lenses in the lens 10. For example, as shown in FIG2 , the aperture 16 may be disposed between the third lens 13 and the fourth lens 14. Of course, the aperture 16 may also be disposed at other locations.

[0104] In some possible implementations, as shown in FIG2 , the lens 10 may further include a cover glass 17 . The cover glass 17 is disposed between the lens element closest to the object side of the lens 10 and the modulation unit 22 , and is used to protect the modulation unit 22 .

[0105] In some possible implementations, the lens 10 may further include a filter (not shown) for correcting color deviation. The filter is arranged between the lens closest to the object side of the lens 10 and the modulation unit 22.

[0106] It should be noted that the lens 10 may be provided with either the cover glass 17 or the filter, or both.

[0107] The structure and performance of the projection device 120 provided in the embodiment of the present application are described below with reference to specific embodiments.

[0108] FIG3 is a schematic structural diagram of a first projection device provided in Example 1 of the present application.

[0109] As shown in FIG3 , a 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 in order from the image side to the object side. The first lens 11 is closest to the image side, and its image side is concave. The fifth lens 15 is closest to the image side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, which may be a DMD or LCOS.

[0110] The first lens element 11 has positive optical power, and the ratio of the focal length f1 of the first lens element 11 to the focal length EFL of the lens 10 is |f1 / EFL| = 3.27. 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| = 2.45. 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| = 2.11. 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| = 1.16. 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| = 1.77.

[0111] The lens element closest to the image side of lens 10 is first lens element 11. The radius of curvature R1 of the image side of first lens element 11 is -115 mm, which is greater than -152 mm and less than -99 mm, meeting the requirements. The ratio of the radius of curvature R1 of the image side of first lens element 11 to the focal length EFL of lens 10 is R1 / EFL = -3.25, which is greater than -4 and less than -2, meeting the requirements.

[0112] The lens element closest to the object side in lens 10 is fifth lens element 15. The radius of curvature of the object side surface of fifth lens element 15, R2, is 194 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio of the radius of curvature of the object side surface of fifth lens element 15, R2 / EFL, to the focal length (EFL) of lens 10 is 5.44, which is greater than -10 and less than 10, meeting the requirements.

[0113] The ratio of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10 is BFL / EFL=0.851, which is greater than 0.8 and less than 0.9, meeting the requirement.

[0114] The focal length EFL of the lens 10 is 35.75 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0115] Table 1 shows the optical parameters of the optical elements in the projection device 120 provided in the first embodiment.

[0116] Among them, S1 is the image side surface of the first lens 11, S2 is the object side surface of the first lens 11, S3 is the image side surface of the second lens 12, S4 is the object side surface of the second lens 12, S5 is the image side surface of the third lens 13, S6 is the object side surface of the third lens 13, S7 is the aperture 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.

[0117] Wherein, R is the radius of curvature of the optical element (such as a lens or glass cover) at the corresponding position of 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 irradiated by the d-ray, and Vd is the Abbe number of the optical element.

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

[0119] Wherein, EFL is the focal length of the lens 10, FOV is the maximum field of view of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side surface of the lens element closest to the image side in the lens 10, R2 is the radius of curvature of the object side surface of the lens element closest to the object side in the lens 10, f1 is the focal length of the first lens element 11, f2 is the focal length of the second lens element 12, f3 is the focal length of the third lens element 13, f4 is the focal length of the fourth lens element 14, and f5 is the focal length of the fifth lens element 15.

[0120] Figure 4 is a diagram of spherical chromatic aberration for the lens shown in Figure 3. In Figure 4, the ordinate represents the normalized pupil coordinate, and the abscissa represents the axial aberration, both in millimeters. The three curves in Figure 4 correspond to the axial aberration curves for light with a wavelength of 625 nm, light with a wavelength of 550 nm, and light with a wavelength of 455 nm after passing through the lens 10 of this embodiment. As can be seen from Figure 4, in this embodiment, the axial aberration is controlled within a very narrow range, resulting in good correction.

[0121] Figure 5 is a plot of astigmatism and field curvature for the lens shown in Figure 3, and Figure 6 is a plot of distortion for the lens shown in Figure 3. In Figure 5, S represents the field curvature for light with a wavelength of 525nm on the meridional image plane, and T represents the field curvature for light with a wavelength of 525nm on the sagittal image plane. In Figure 6, the solid line represents the distortion for light with a central wavelength of 525nm passing through the lens 10 of this embodiment. In this embodiment, combining Figures 5 and 6 shows that the lens 10 provided in this embodiment controls field curvature and distortion within the appropriate ranges, meeting the requirements of use.

[0122] FIG7 is a schematic structural diagram of a second projection device provided in Example 2 of the present application.

[0123] As shown in FIG7 , a 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 in order from the image side to the object side. The first lens 11 is closest to the image side, and its image-side surface is concave. The fifth lens 15 is closest to the image side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, which may be a DMD or LCOS.

[0124] The first lens element 11 has positive optical power, and the ratio of the focal length f1 of the first lens element 11 to the focal length EFL of the lens 10 is: |f1 / EFL| = 3.33. 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| = 2.32. 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| = 2.227. 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| = 1.188. 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| = 1.787.

[0125] The lens element closest to the image side in lens 10 is first lens element 11. The radius of curvature of the image side of first lens element 11, R1, is -101.6 mm, which is greater than -152 mm and less than -99 mm, meeting the requirements. The ratio of the radius of curvature R1 of the image side of first lens element 11 to the focal length EFL of lens 10, R1 / EFL, is -2.8968, which is greater than -4 and less than -2, meeting the requirements.

[0126] The lens element closest to the object side in lens 10 is fifth lens element 15. The object-side curvature radius R2 of fifth lens element 15 is 210.16 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio of the object-side curvature radius R2 of fifth lens element 15 to the focal length EFL of lens 10 is R2 / EFL = 5.9917, which is greater than -10 and less than 10, meeting the requirements.

[0127] The ratio of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10 is BFL / EFL=0.8508, which is greater than 0.8 and less than 0.9, meeting the requirement.

[0128] The focal length EFL of the lens 10 is 35.07 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0129] Table 3 shows the optical parameters of the optical elements in the projection device 120 provided in the second embodiment.

[0130] Among them, S1 is the image side surface of the first lens 11, S2 is the object side surface of the first lens 11, S3 is the image side surface of the second lens 12, S4 is the object side surface of the second lens 12, S5 is the image side surface of the third lens 13, S6 is the object side surface of the third lens 13, S7 is the aperture 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] Wherein, R is the radius of curvature of the optical element (such as a lens or glass cover) at the corresponding position of 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 irradiated by the d-ray, and Vd is the Abbe number of the optical element.

[0132] Table 4 shows the optical parameters of the lens 10 provided in the second embodiment.

[0133] Wherein, EFL is the focal length of the lens 10, FOV is the maximum field of view of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side surface of the lens element closest to the image side in the lens 10, R2 is the radius of curvature of the object side surface of the lens element closest to the object side in the lens 10, f1 is the focal length of the first lens element 11, f2 is the focal length of the second lens element 12, f3 is the focal length of the third lens element 13, f4 is the focal length of the fourth lens element 14, and f5 is the focal length of the fifth lens element 15.

[0134] Figure 8 is a diagram of spherical chromatic aberration for the lens shown in Figure 7. In Figure 8, the ordinate represents the normalized pupil coordinate, and the abscissa represents the axial aberration, both in millimeters. The three curves in Figure 8 correspond to the axial aberration curves for light with a wavelength of 625 nm, light with a wavelength of 550 nm, and light with a wavelength of 455 nm after passing through the lens 10 of this embodiment. As can be seen from Figure 8, in this embodiment, the axial aberration is controlled within a very narrow range, resulting in good correction.

[0135] Figure 9 is a plot of astigmatism and field curvature for the lens shown in Figure 8, and Figure 10 is a plot of distortion for the lens shown in Figure 8. In Figure 9, S represents the field curvature for light with a wavelength of 525nm on the meridional image plane, and T represents the field curvature for light with a wavelength of 525nm on the sagittal image plane. In Figure 10, the solid line represents the distortion for light with a central wavelength of 525nm passing through the lens 10 of this embodiment. In this embodiment, combining Figures 9 and 10 shows that the lens 10 provided by this embodiment controls field curvature and distortion within the appropriate ranges, meeting the requirements of use.

[0136] FIG11 is a schematic structural diagram of a third projection device provided in Example 3 of the present application.

[0137] As shown in FIG11 , a 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 in order from the image side to the object side. The first lens 11 is closest to the image side, and its image-side surface is concave. The fifth lens 15 is closest to the image side, and the cover glass 17 is disposed between the fifth lens 15 and the modulation unit 22. The modulation unit 22 may be a projection chip, which may be a DMD or LCOS.

[0138] The first lens element 11 has positive optical power, and the ratio of the focal length f1 of the first lens element 11 to the focal length EFL of the lens 10 is |f1 / EFL| = 3.138. 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| = 2.585. 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| = 2.224. 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| = 1.188. 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| = 1.728.

[0139] The lens element closest to the image side in lens 10 is first lens element 11. The radius of curvature of the image side surface of first lens element 11, R1, is -132.25 mm, which is greater than -152 mm and less than -99 mm, meeting the requirements. The ratio of the radius of curvature R1 of the image side surface of first lens element 11 to the focal length EFL of lens 10, R1 / EFL, is -3.77, which is greater than -4 and less than -2, meeting the requirements.

[0140] The lens element closest to the object side in lens 10 is fifth lens element 15. The radius of curvature of the object side surface of fifth lens element 15, R2, is 199.505 mm, which is greater than -380 mm and less than 380 mm, meeting the requirements. The ratio of the radius of curvature R2 of the object side surface of fifth lens element 15 to the focal length EFL of lens 10, R2 / EFL, is -5.688, which is greater than -10 and less than 10, meeting the requirements.

[0141] The ratio of the back focal length BFL of the lens 10 to the focal length EFL of the lens 10 is BFL / EFL=0.8502, which is greater than 0.8 and less than 0.9, meeting the requirement.

[0142] The focal length EFL of the lens 10 is 35.075 mm, which is greater than 33 mm and less than 38 mm, meeting the requirements.

[0143] Table 5 shows the optical parameters of the optical elements in the projection device 120 provided in the third embodiment.

[0144] Among them, S1 is the image side surface of the first lens 11, S2 is the object side surface of the first lens 11, S3 is the image side surface of the second lens 12, S4 is the object side surface of the second lens 12, S5 is the image side surface of the third lens 13, S6 is the object side surface of the third lens 13, S7 is the aperture 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.

[0145] Wherein, R is the radius of curvature of the optical element (such as a lens or glass cover) at the corresponding position of 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 irradiated by the d-ray, and Vd is the Abbe number of the optical element.

[0146] Table 6 shows the optical parameters of the lens 10 provided in the third embodiment.

[0147] Wherein, EFL is the focal length of the lens 10, FOV is the maximum field of view of the lens 10, Fno is the aperture of the lens 10, BFL is the back focal length of the lens 10, TTL is the total optical length of the lens 10, R1 is the radius of curvature of the image side surface of the lens element closest to the image side in the lens 10, R2 is the radius of curvature of the object side surface of the lens element closest to the object side in the lens 10, f1 is the focal length of the first lens element 11, f2 is the focal length of the second lens element 12, f3 is the focal length of the third lens element 13, f4 is the focal length of the fourth lens element 14, and f5 is the focal length of the fifth lens element 15.

[0148] Figure 12 is a diagram of spherical chromatic aberration for the lens shown in Figure 11. In Figure 12, the ordinate represents the normalized pupil coordinate, and the abscissa represents the axial aberration, both expressed in millimeters. The three curves in Figure 12 correspond to the axial aberration curves for light with a wavelength of 625 nm, light with a wavelength of 550 nm, and light with a wavelength of 455 nm after passing through the lens 10 of this embodiment. As can be seen from Figure 12, in this embodiment, the axial aberration is controlled within a very narrow range, resulting in good correction.

[0149] Figure 13 is a plot of astigmatism and field curvature for the lens shown in Figure 11, and Figure 14 is a plot of distortion for lens 10 shown in Figure 11. In Figure 13, S represents the field curvature for light with a wavelength of 525nm on the meridional image plane, and T represents the field curvature for light with a wavelength of 525nm on the sagittal image plane. In Figure 14, the solid line represents the distortion for light with a central wavelength of 525nm passing through lens 10 of this embodiment. In this embodiment, combining Figures 13 and 14 shows that lens 10 provided in this embodiment controls field curvature and distortion within the appropriate ranges, meeting usage requirements.

[0150] In the description of the embodiments of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to a fixed connection, an indirect connection via an intermediate medium, internal communication between two components, or an interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on specific circumstances.

[0151] In the embodiments of the present application, any device or element referred to or implied must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present application. In the description of the embodiments of the present application, the meaning of "plurality" is two or more, unless otherwise specifically specified.

[0152] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0153] The term "plurality" in this document refers to two or more. The term "and / or" in this document simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. Furthermore, the character " / " in this document generally indicates an "or" relationship between the related objects; in a formula, the character " / " indicates a "division" relationship between the related objects.

[0154] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0155] It can be understood that in the embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean 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 the present application.

Claims

1. A lens, characterized in that: comprising at least five lenses arranged from the image side to the object side; The image side surface of the lens closest to the image side in the lens is a concave surface, the number of the lenses with positive optical power in the lens is at least three, and the number of the lenses with negative optical power in the lens is at least one, wherein: When the number of the lens having negative refractive power is one, the lens having negative refractive power is disposed between the lens closest to the image side and the lens closest to the object side in the lens.

2. The lens according to claim 1, characterized in that: The lens satisfies the relationship: 0.8<BFL / EFL<0.9, wherein 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: 33mm<EFL<38mm, wherein 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: -4<R1 / EFL<-2, wherein R1 is the radius of curvature of the image side surface of the lens closest to the image side in the lens, and EFL is the focal length of the lens.

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

6. The lens according to any one of claims 1 to 5, characterized in that: The lens satisfies the relationship: -10<R2 / EFL<10, wherein R2 is the radius of curvature of the object side surface of the lens closest to the object side in the lens, and EFL is the focal length of the lens.

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

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

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

10. A projection device, characterized in that: The invention comprises a display unit and the lens as claimed in any one of claims 1 to 9, wherein the display unit is used to emit imaging light to the lens.

11. The projection device according to claim 10, 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 by the light source unit to generate the imaging light, and emit the imaging light to the lens.

12. The projection device according to claim 11, characterized in that: The display unit further includes a reflection unit, and the reflection unit is used to reflect the light beam emitted by the light source unit to the modulation unit.

13. A vehicle lamp device, characterized in that: The invention comprises a housing and the projection device according to any one of claims 10 to 12, wherein at least a part of the projection device is arranged inside the housing.

14. A means of transport, characterized in that: Comprising the vehicle light device as claimed in claim 13.

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