A five-piece glass lens vehicle lamp projection lens

Abstract

This invention provides a five-element glass lens for automotive headlight projection, belonging to the field of automotive lighting technology. The five-element glass lens comprises a first positive biconvex lens, a negative biconcave lens, a first positive meniscus lens, a second positive biconvex lens, and a second positive meniscus lens, arranged sequentially along the optical axis from the object plane to the image plane. The image plane side surface of the first positive meniscus lens is convex, and the object plane side surface is concave. Similarly, the object plane side surface of the second positive meniscus lens is convex, and the image plane side surface is concave. This invention's automotive headlight projection lens features a large relative aperture, high transmittance, low distortion, and strong high and low temperature stability, meeting the dual requirements of illumination and imaging in automotive projection headlights.

Description

Technical Field

[0001] This invention belongs to the field of automotive lighting technology, specifically relating to a five-element glass lens for automotive lighting projection. Background Technology

[0002] Currently, the development of new energy vehicles is progressing rapidly amidst the wave of technological advancements, especially the popularization of intelligent technology and social development. Consequently, more technologically advanced and intelligent in-vehicle components, functions, and driving experiences are increasingly favored. Among these, headlights are a key component that can bring a better driving experience and more efficient travel. Traditional gasoline-powered vehicle headlights only provide illumination, and their light distribution is uneven, illuminance utilization is low, and high beams can easily dazzle oncoming vehicles. They also cannot achieve precise light pattern control and intelligent interaction. Traditional headlights often use reflector bowls or single-lens structures, making it difficult to achieve projection imaging and supporting functions such as pattern projection, vehicle-to-everything (V2X) communication, and ADAS (Advanced Driver Assistance Systems) lane marking. Furthermore, existing headlight projection lenses often use a glass-plastic hybrid structure. Plastic lenses are prone to thermal expansion and contraction and surface drift under high and low temperature cycling conditions in vehicles, leading to focal length shift, reduced resolution, and light spot distortion. Plastic lenses also have weak temperature resistance, are prone to yellowing, and have poor vibration and impact resistance, making their lifespan insufficient to meet the requirements of the entire vehicle.

[0003] In addition, automotive lenses have stringent requirements for overall length, F-number, and temperature stability. There is a lack of automotive headlight projection lenses on the market that are simple in structure, highly reliable, high in brightness, compatible with DMD chips, and have high and low temperature stability. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a five-element glass lens for automotive headlight projection, which has the characteristics of large relative aperture, high transmittance, low distortion, and strong high and low temperature stability, in order to meet the dual needs of automotive projection headlights for illumination and imaging.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a five-element glass lens for vehicle headlight projection, comprising a first positive biconvex lens, a negative biconcave lens, a first positive meniscus lens, a second positive biconvex lens, and a second positive meniscus lens arranged sequentially along the optical axis from the object plane to the image plane. The image plane side surface of the first positive meniscus lens is convex, and the object plane side surface is concave. The object plane side surface of the second positive meniscus lens is convex, and the image plane side surface is concave.

[0006] Optionally, the front surface R1 of the first positive biconvex lens has a radius of curvature of +76.2mm to +76.6mm, the rear surface R2 has a radius of curvature of -509.0mm to -509.4mm, a thickness of 4.45mm to 4.55mm, and a refractive index of 1.90 to 1.91.

[0007] Furthermore, the front surface R3 of the negative biconcave lens has a radius of curvature of -27.8mm to -28.1mm, the rear surface R4 has a radius of curvature of 83.2mm to 83.5mm, a thickness of 4.95mm to 5.05mm, and a refractive index of 1.84 to 1.85.

[0008] Furthermore, the front surface R5 of the first positive meniscus lens has a radius of curvature of -70.7mm to -71.0mm, the rear surface R6 has a radius of curvature of -38.1mm to -38.5mm, a thickness of 7.65mm to 7.75mm, and a refractive index of 1.63 to 1.64.

[0009] Furthermore, the radius of curvature of the front surface R7 of the second positive biconvex lens is +198.2mm to +198.6mm, the radius of curvature of the rear surface R8 is -34.95mm to -35.05mm, the thickness is 9.25mm to 9.35mm, and the refractive index is 1.61 to 1.62.

[0010] Furthermore, the radius of curvature of the front surface R9 of the second positive meniscus lens is +45.3mm to +45.4mm, the radius of curvature of the rear surface R10 is +123.3mm to +123.6mm, the thickness is 4.95mm to 5.05mm, and the refractive index is 1.77 to 1.78.

[0011] Furthermore, an aperture stop is provided between the first positive biconvex lens and the negative biconcave lens.

[0012] Further, the air gap between the vertex of the rear surface of the first positive biconvex lens and the aperture stop is 0mm~0.1mm, the air gap between the aperture stop and the vertex of the adjacent side surface of the negative biconcave lens is 14.4mm~14.5mm, the air gap between the vertex of the rear surface of the negative biconcave lens and the vertex of the adjacent side surface of the first positive meniscus lens is 3.75mm~3.81mm, the air gap between the vertex of the rear surface of the first positive meniscus lens and the vertex of the adjacent side surface of the second positive biconvex lens is 0.1mm~0.3mm, and the air gap between the vertex of the rear surface of the second positive biconvex lens and the vertex of the adjacent side surface of the second positive meniscus lens is 0.1mm~0.3mm.

[0013] Furthermore, a protective glass is provided on the image plane side of the second positive meniscus lens.

[0014] Furthermore, the aforementioned five-element glass lens for vehicle headlight projection is compatible with a 0.46-inch DMD chip, has a maximum half-field of view of 7.8°, a pixel diameter of Φ11.6mm, a focal length EFL of 42.0mm~43.0mm, an F-number of 1.19~1.23, an optical total length TTL of 90.5~90.7mm, a lens length of 50.0~50.5mm, a temperature resistance of -40℃~70℃, a resolution of approximately 480P, and supports high-brightness projection illumination at a distance of 4~12m.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a five-element glass lens for vehicle headlight projection, achieving the effects of a simple structure, high reliability, high brightness, compatibility with DMD chips, and stable operation at temperatures ranging from -40℃ to 70℃.

[0016] This invention employs a five-element all-glass lens structure, avoiding the problems of thermal expansion and contraction, surface drift, yellowing, and poor impact resistance that easily occur in traditional glass-plastic hybrid lenses under high or low temperature environments. This invention achieves a passive, heat-free design by matching the optical parameters and surface design of each lens material. MTF curves show that the lens of this invention maintains stable center resolution, low astigmatism, and reliable image quality within a temperature range of -40℃ to 70℃, meeting the usage requirements of automotive headlights within this temperature range.

[0017] The absolute value of the distortion of the vehicle headlight projection lens of this invention is less than 1%, which is low and has high geometric fidelity. It can realize projection imaging, light pattern projection and intelligent switching between near and far beams.

[0018] The vehicle headlight projection lens of this invention adopts a large relative aperture design with an F number of 1.19 to 1.23. Combined with an optimized optical path structure, it has a large light transmission and higher illuminance. Within the full field of view range of 0° to 7.8°, the relative illuminance decreases by only about 10%, and the brightness distribution is uniform within an illumination distance of 4 to 12 meters, which can provide the driver with a more comfortable field of vision.

[0019] This invention, using five all-glass lenses, achieves a total optical length of 90.5 mm to 90.7 mm and a lens length of 50.0 mm to 50.5 mm through reasonable optical power distribution and surface design. The compact structure allows it to be easily installed in the limited internal space of automotive headlights, meeting the requirements of vehicle components for miniaturization and weight reduction.

[0020] This invention is specifically optimized for 0.46-inch DMD chips, with a maximum half-field of view of 7.8°, a pixel diameter of Φ11.6 mm, and a focal length of 42.0 mm to 43.0 mm. Through optical design optimization, this invention can control the angle of the principal rays emitted to the image plane within the receiving angle range required by the DMD chip, thereby achieving optical matching with the DMD chip.

[0021] This invention employs a five-element all-glass lens, which gives the lens excellent temperature resistance, humidity resistance, and vibration resistance, meeting the lifespan requirements of the entire vehicle's life cycle and reducing after-sales maintenance costs.

[0022] The five-element all-glass lens of this invention is a pure spherical design, which is easy to process, convenient to inspect, and has a high yield, making it suitable for mass production of automotive-grade lenses.

[0023] In summary, the five-element glass lens for vehicle headlight projection provided by this invention has significant advantages in terms of wide-temperature stability, imaging resolution, distortion control, illuminance uniformity, structural compactness, and DMD compatibility. It is particularly suitable for the application requirements of new energy vehicles for high-reliability and intelligent vehicle headlight projection systems. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 : An optical system arrangement diagram of the projection lens of the vehicle headlights of this invention; Figure 2 : An optical system arrangement diagram of the vehicle headlight projection lens of this invention without light transmission; Figure 3 MTF curve of the vehicle headlight projection lens of this invention at an ambient temperature of -40℃; Figure 4 MTF curve of the vehicle headlight projection lens of this invention at an ambient temperature of +20℃; Figure 5 MTF curve of the vehicle headlight projection lens of this invention at an ambient temperature of +70℃; Figure 6 : A dot pattern representation diagram of the projection lens of the vehicle headlights of this invention; Figure 7 : A distortion representation diagram of the vehicle headlight projection lens of this invention; Figure 8 : Relative illuminance curve of the vehicle headlight projection lens of this invention; Among them, 1. First positive biconvex lens; 2. Aperture stop; 3. Negative biconcave lens; 4. First positive meniscus lens; 5. Second positive biconvex lens; 6. Second positive meniscus lens; 7. Protective glass; 8. DMD chip. Detailed Implementation

[0026] To better understand the present invention, the following embodiments further illustrate the content of the invention, but the scope of protection of the present invention is not limited to the following embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0027] It should be noted that in this specification, the terms "first," "second," etc., are used only to distinguish one feature from another and do not imply any limitation on the features. Therefore, without departing from the teachings of the invention, the first lens discussed below may also be referred to as the second lens or the third lens.

[0028] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms (e.g., those defined in common dictionaries) shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art and shall not be interpreted in an idealized or overly formal sense unless expressly so specified herein.

[0029] The present invention provides a five-element glass lens for vehicle headlight projection, comprising a first positive biconvex lens 1, a negative biconcave lens 3, a first positive meniscus lens 4, a second positive biconvex lens 5, and a second positive meniscus lens 6 arranged sequentially along the optical axis from the object plane to the image plane.

[0030] In some embodiments, the image-side surface of the first positive meniscus lens 4 is convex and the object-side surface is concave, and the object-side surface of the second positive meniscus lens 6 is convex and the image-side surface is concave.

[0031] This invention employs five all-glass lenses to ensure high and low temperature stability, avoiding problems such as thermal drift, yellowing, and poor impact resistance associated with plastic lenses. The fewer lenses reduce the air-glass interface, lowering reflection loss and increasing transmittance, while also simplifying assembly and enhancing reliability. Through alternating optical powers, specific surface shapes, and the selection of all-glass materials, the five lenses collectively achieve a large relative aperture, high transmittance, low distortion, and high and low temperature stability.

[0032] In some embodiments, the radius of curvature of the front surface R1 of the first positive biconvex lens 1 ranges from +76.2 mm to +76.6 mm, and the radius of curvature of the rear surface R2 ranges from -509.0 mm to -509.4 mm; the thickness t1 ranges from 4.45 mm to 4.55 mm; and the refractive index n1 ranges from 1.90 to 1.91. Meeting these ranges can improve luminous flux and transmittance, supporting the requirements of large relative aperture designs.

[0033] In some embodiments, an aperture stop 2 is provided between the first positive biconvex lens 1 and the negative biconcave lens 3.

[0034] In some embodiments, the air gap d1 between the vertex of the rear surface of the first positive biconvex lens 1 and the aperture stop 2 ranges from 0 mm to 0.1 mm. In this way, the aperture stop 2 is close to the first positive biconvex lens 1, maximizing the utilization of its light transmission aperture.

[0035] In some embodiments, the air gap d2 between the aperture stop 2 and the adjacent side vertices of the negative biconcave lens 3 ranges from 14.4 mm to 14.5 mm. This provides a larger space to fully diverge light, which, in conjunction with the first positive biconvex lens 1, enhances the ability to correct spherical aberration and chromatic aberration.

[0036] In some embodiments, the radius of curvature of the front surface R3 of the negative biconcave lens 3 ranges from -27.8 mm to -28.1 mm, and the radius of curvature of the rear surface R4 ranges from 83.2 mm to 83.5 mm; the thickness t2 ranges from 4.95 mm to 5.05 mm; and the refractive index n2 ranges from 1.84 to 1.85. Meeting these ranges helps to reduce distortion and improve transmittance.

[0037] In some embodiments, the air gap d3 between the rear surface vertex of the negative biconcave lens 3 and the adjacent side vertex of the first positive meniscus lens 4 ranges from 3.75 mm to 3.81 mm. This avoids the lenses colliding with each other during vibration and does not introduce additional light energy loss, thus maintaining high transmittance.

[0038] In some embodiments, the radius of curvature of the front surface R5 of the first positive meniscus lens 4 ranges from -70.7 mm to -71.0 mm, and the radius of curvature of the rear surface R6 ranges from -38.1 mm to -38.5 mm; the thickness t3 ranges from 7.65 mm to 7.75 mm; and the refractive index n3 ranges from 1.63 to 1.64. Meeting these ranges is beneficial for improving the edge imaging quality under large relative apertures and enhancing vibration resistance.

[0039] In some embodiments, the air gap d4 between the rear surface vertex of the first positive meniscus lens 4 and the adjacent side vertex of the second positive biconvex lens 5 ranges from 0.1 mm to 0.3 mm.

[0040] In some embodiments, the radius of curvature of the front surface R7 of the second positive biconvex lens 5 ranges from +198.2 mm to +198.6 mm, and the radius of curvature of the rear surface R8 ranges from -34.95 mm to -35.05 mm; the thickness t4 ranges from 9.25 mm to 9.35 mm; and the refractive index n4 ranges from 1.61 to 1.62. Meeting these ranges is beneficial for achieving a large relative aperture while effectively shortening the overall optical length, meeting the requirements for compact vehicle installation; the large thickness improves structural rigidity; and the lower refractive index combined with the large curvature difference achieves the required optical power without introducing additional spherical aberration, thus reducing distortion.

[0041] In some embodiments, the air gap d5 between the rear surface vertex of the second positive biconvex lens 5 and the adjacent side vertex of the second positive meniscus lens 6 ranges from 0.1 mm to 0.3 mm.

[0042] In some embodiments, the radius of curvature of the front surface R9 of the second positive meniscus lens 6 ranges from +45.3 mm to +45.4 mm, and the radius of curvature of the rear surface R10 ranges from +123.3 mm to +123.6 mm; the thickness t5 ranges from 4.95 mm to 5.05 mm; and the refractive index n5 ranges from 1.77 to 1.78. By satisfying these ranges, the specific surface shape combined with a high refractive index effectively compresses the exit angle of the principal ray, allowing the light to be incident almost perpendicularly onto the DMD chip 8, improving light energy utilization, reducing edge vignetting, and enhancing illumination uniformity under a large relative aperture; further, it corrects residual distortion, resulting in a full field-of-view distortion of <1%.

[0043] In some embodiments, a protective glass 7 is disposed on the image plane side of the second positive meniscus lens 6. The protective glass 7 serves to protect the DMD chip 8 from dust, moisture, and physical damage.

[0044] Examples 1-3: Refer to Figure 1 and Figure 2 A five-element glass lens for vehicle headlight projection includes a first positive biconvex lens 1, an aperture 2, a negative biconcave lens 3, a first positive meniscus lens 4, a second positive biconvex lens 5, a second positive meniscus lens 6, and a protective glass 7 arranged sequentially along the optical axis from the object plane to the image plane. The image plane side surface of the first positive meniscus lens 4 is convex, and the object plane side surface is concave. The object plane side surface of the second positive meniscus lens 6 is convex, and the image plane side surface is concave.

[0045] The specific parameters of the first positive biconvex lens 1, aperture 2, negative biconcave lens 3, first positive meniscus lens 4, second positive biconvex lens 5, and second positive meniscus lens 6 in Examples 1-3 are shown in Table 1 below.

[0046] Table 1 Specific Parameters Figure 3-5The figure shows the MTF (modulation transfer function) curves of Example 1 at ambient temperatures of -40℃, +20℃, and +70℃, respectively. These curves represent the lens imaging modulation at different spatial frequencies within each field of view. The horizontal axis represents the spatial frequency (unit: period / mm), and the vertical axis represents the modulation transfer function value. The figure shows the tangential (T) and arc (S) modulation transfer function curves at different field of view angles. It can be seen from the figure that the lens of the present invention exhibits stable center resolution and good tangential performance within the vehicle-mounted temperature range of -40℃ to 70℃.

[0047] Figure 6 The diagram shows the dot pattern representation of Embodiment 1, illustrating the actual imaging spot shape, size, and energy distribution in each field of view of the lens. As can be seen from the diagram, the dot pattern in the on-axis field of view of the lens of the present invention exhibits a regular concentric circle distribution, with good spherical aberration correction.

[0048] Figure 7 The diagram illustrates the distortion performance of Example 1, showing the F-Tanθ distortion of light rays at different image heights on the imaging plane. The horizontal axis represents the F-Tanθ distortion value (unit: %), and the vertical axis represents the half field of view (unit: °). As can be seen from the diagram, the lens of the present invention exhibits extremely low F-Tanθ distortion (<1%) and excellent geometric fidelity.

[0049] Figure 8 The relative illumination curve of Example 1 is shown, which represents the relative illumination values ​​at different field-of-view angles on the imaging plane. The horizontal axis represents the half-field angle (unit: °), and the vertical axis represents the relative illumination (unit: %). As can be seen from the figure, the lens of the present invention has extremely excellent relative illumination, with a decrease of only about 10% across the entire field of view, and excellent uniformity of image plane brightness.

[0050] The five-element glass lens for vehicle headlight projection designed according to the above scheme has a maximum half field of view of 7.8°, a pixel diameter of Φ11.6mm, a focal length (EFL) of 42.0mm~43.0mm, an F-number of 1.19~1.23, a total optical length (TTL) of 90.5~90.7mm, a lens length of 50.0~50.5mm, a temperature resistance range of -40℃~70℃, a resolution of approximately 480P, and high-brightness projection illumination at a range of 4~12m.

[0051] Compared with the prior art, the five-element glass lens of the present invention provides a superior vehicle headlight projection lens with excellent performance. It achieves the effect of a compact and simple structure, high reliability, high brightness, DMD chip compatibility, and stable operation at -40℃ to 70℃.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered by the claims of the present invention.

Claims

1. A five-piece glass lens automotive lamp projection lens characterized by: The first positive biconvex lens (1), the second negative biconcave lens (3), the third positive meniscus lens (4), the fourth positive biconvex lens (5), and the fifth positive meniscus lens (6) are arranged sequentially along the optical axis from the object plane to the image plane. The image plane side surface of the first positive meniscus lens (4) is convex and the object plane side surface is concave. The object plane side surface of the second positive meniscus lens (6) is convex and the image plane side surface is concave.

2. A five-element glass lens vehicle lamp projection lens according to claim 1, characterized in that: The first positive biconvex lens (1) has a front surface R1 with a radius of curvature of +76.2mm to +76.6mm, a rear surface R2 with a radius of curvature of -509.0mm to -509.4mm, a thickness of 4.45mm to 4.55mm, and a refractive index of 1.90 to 1.

91.

3. The vehicle headlight projection lens with a five-element glass lens as described in claim 1, characterized in that: The negative biconcave lens (3) has a front surface R3 radius of curvature of -27.8mm to -28.1mm, a rear surface R4 radius of curvature of 83.2mm to 83.5mm, a thickness of 4.95mm to 5.05mm, and a refractive index of 1.84 to 1.

85.

4. A five-element glass lens for vehicle headlight projection as described in claim 1, characterized in that: The first positive meniscus lens (4) has a front surface R5 radius of curvature of -70.7mm to -71.0mm, a rear surface R6 radius of curvature of -38.1mm to -38.5mm, a thickness of 7.65mm to 7.75mm, and a refractive index of 1.63 to 1.

64.

5. A five-element glass lens for vehicle headlight projection as described in claim 1, characterized in that: The second positive biconvex lens (5) has a front surface R7 radius of curvature of +198.2mm to +198.6mm, a rear surface R8 radius of curvature of -34.95mm to -35.05mm, a thickness of 9.25mm to 9.35mm, and a refractive index of 1.61 to 1.

62.

6. A five-element glass lens for vehicle headlight projection as described in claim 1, characterized in that: The second positive meniscus lens (6) has a front surface R9 radius of curvature of +45.3mm to +45.4mm, a rear surface R10 radius of curvature of +123.3mm to +123.6mm, a thickness of 4.95mm to 5.05mm, and a refractive index of 1.77 to 1.

78.

7. A vehicle headlight projection lens with a five-element glass lens as described in any one of claims 1-6, characterized in that: An aperture stop (2) is provided between the first positive biconvex lens (1) and the negative biconcave lens (3).

8. A five-element glass lens for vehicle headlight projection as described in claim 7, characterized in that: The air gap between the vertex of the rear surface of the first positive biconvex lens (1) and the aperture (2) is 0 mm to 0.1 mm. The air gap between the aperture (2) and the vertex of the adjacent side surface of the negative biconcave lens (3) is 14.4 mm to 14.5 mm. The air gap between the vertex of the rear surface of the negative biconcave lens (3) and the vertex of the adjacent side surface of the first positive meniscus lens (4) is 3.75 mm to 3.81 mm. The air gap between the vertex of the rear surface of the first positive meniscus lens (4) and the vertex of the adjacent side surface of the second positive biconvex lens (5) is 0.1 mm to 0.3 mm. The air gap between the vertex of the rear surface of the second positive biconvex lens (5) and the vertex of the adjacent side surface of the second positive meniscus lens (6) is 0.1 mm to 0.3 mm.

9. A five-element glass lens for vehicle headlight projection as described in claim 8, characterized in that: A protective glass (7) is provided on the image plane side of the second positive meniscus lens (6).

10. A vehicle headlight projection lens with a five-element glass lens as described in any one of claims 1-9, characterized in that: It is compatible with a 0.46-inch DMD chip (8), with a maximum half field of view of 7.8°, a pixel diameter of Φ11.6mm, a focal length EFL of 42.0mm~43.0mm, an F number of 1.19~1.23, an optical total length TTL of 90.5~90.7mm, and a lens length of 50.0~50.5mm.

Images