Vehicle-mounted projection optical system and motor vehicle

Abstract

The present invention discloses a vehicle-mounted projection optical system and a motor vehicle. The vehicle-mounted projection optical system includes a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, a galvanometer, and a prism, which are arranged in sequence from the object side to the image side. Due to the large aperture of the first lens, more light information can be collected under the same focal length, achieving a clear imaging effect in weak light and correcting axial chromatic aberration at the same time. The following six lenses can correct system chromatic aberration, spherical aberration and image curvature, increase the system aperture, and ensure the imaging performance of the optical system at high temperature without defocusing, so that the vehicle-mounted projection optical system can support an aperture of F1.7, and the total optical length is controlled within 64.2 mm, thereby providing a low-cost, high-temperature, non-defocused, large aperture and small vehicle-mounted projection optical system.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, in particular to a vehicle-mounted projection optical system and a motor vehicle. Background Art

[0002] Currently, vehicle-mounted projection optical systems generally have the following disadvantages: high cost, small aperture, large size, and out-of-focus under high temperature conditions.

[0003] Currently, the market often sacrifices other aspects to improve certain aspects. For example, to achieve ultra-low costs, all-plastic lenses are used, resulting in out-of-focus in high-temperature environments. Some lenses also incorporate multiple glass elements to meet resolution requirements and ensure performance in extreme environments, increasing costs and hindering their widespread adoption and promotion. Summary of the Invention

[0004] The main purpose of the present invention is to provide a vehicle-mounted projection optical system and a motor vehicle, aiming to provide a low-cost, high-temperature, non-defocused, large aperture, and small vehicle-mounted projection optical system.

[0005] To achieve the above-mentioned objectives, the present invention proposes a vehicle-mounted projection optical system, wherein the vehicle-mounted projection optical system has an object side and an image side arranged opposite to each other along the optical axis direction, and the vehicle-mounted projection optical system includes a first lens with negative optical focal length, a second lens with negative optical focal length, a third lens with negative optical focal length, a fourth lens with positive optical focal length, a fifth lens with negative optical focal length, a sixth lens with positive optical focal length, a seventh lens with positive optical focal length, a galvanometer, a prism and a photosensitive chip, arranged in sequence from the object side to the image side, so that the vehicle-mounted projection optical system can support an aperture of F1.7, and the total optical length is controlled within 64.2mm.

[0006] Optionally, the optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fourth lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The vehicle-mounted projection optical system meets the following conditions:

[0007] and and and and and and

[0008] Optionally, the first lens and the seventh lens are aspherical lenses, and the surface shapes of the first lens and the seventh lens satisfy the formula:

[0009]

[0010] Wherein, c is the curvature corresponding to the radius, y is the radial coordinate, k is the conic quadratic curve coefficient, and a1 to a8 represent the coefficients corresponding to each radial coordinate, respectively.

[0011] Optionally, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are spherical lenses.

[0012] Optionally, the first lens is made of plastic.

[0013] Optionally, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are made of glass.

[0014] Optionally, the seventh lens is made of low-softening glass.

[0015] Optionally, a stop is provided between the fourth lens and the fifth lens.

[0016] Optionally, the vehicle-mounted projection optical system further includes a protective glass, which is disposed between the seventh lens and the photosensitive chip.

[0017] The present invention also provides a motor vehicle, which includes a vehicle-mounted projection optical system, wherein the vehicle-mounted projection optical system has an object side and an image side arranged opposite to each other along the optical axis direction, and the vehicle-mounted projection optical system includes a first lens with negative optical focal length, a second lens with negative optical focal length, a third lens with negative optical focal length, a fourth lens with positive optical focal length, a fifth lens with negative optical focal length, a sixth lens with positive optical focal length, a seventh lens with positive optical focal length, a galvanometer, a prism and a photosensitive chip, which are arranged in sequence from the object side to the image side, so that the vehicle-mounted projection optical system can support an aperture of F1.7 and the total optical length is controlled within 64.2 mm.

[0018] In the technical solution provided by the present invention, a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, a galvanometer, and a prism are arranged in sequence from the object side to the image side. Due to the large aperture of the first lens, more light information can be collected under the same focal length, achieving the effect of clear imaging in weak light, and at the same time correcting axial chromatic aberration. Through the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, and the seventh lens, system chromatic aberration, spherical aberration, and image curvature can be corrected, the system aperture is increased, and the imaging performance of the optical system at high temperature is guaranteed without defocus, so that the vehicle-mounted projection optical system can support an aperture of F1.7, and the total optical length is controlled within 64.2 mm, thereby providing a low-cost, high-temperature, non-defocused, large aperture, and small-sized vehicle-mounted projection optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 A schematic structural diagram of an embodiment of a vehicle-mounted projection optical system provided by the present invention;

[0021] Figure 2 for Figure 1 MTF curve of the vehicle-mounted projection optical system in the visible light band;

[0022] Figure 3 for Figure 1 Defocus curve of the vehicle-mounted projection optical system in the visible light band at an ambient temperature of 20°C.

[0023] Description of Figure Numbers:

[0024] Label name Label name 1 First lens 7 Seventh lens 2 Second lens 8 Galvanometer 3 The third lens 9 Prism 4 Fourth lens 10 Photosensitive chip 5 Fifth lens 11 aperture 6 Sixth lens 12 Protective glass

[0025] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0028] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] Current automotive projection optical systems suffer from common shortcomings: high cost, small aperture, large size, and defocusing at high temperatures. Market solutions typically improve certain aspects at the expense of others. For example, to achieve ultra-low costs, all-plastic lenses are used, resulting in defocusing in high-temperature environments. Some lenses also incorporate multiple glass elements to meet resolution requirements and ensure performance in extreme environments, increasing costs and hindering their widespread adoption.

[0030] In order to solve the above problems, the present invention provides a vehicle-mounted projection optical system. Figure 1 This is a specific embodiment of the vehicle-mounted projection optical system provided by the present invention.

[0031] See also Figure 1The vehicle-mounted projection optical system has an object side and an image side arranged opposite to each other along the optical axis direction. The vehicle-mounted projection optical system includes a first lens 1 with negative optical focal length, a second lens 2 with negative optical focal length, a third lens 3 with negative optical focal length, a fourth lens 4 with positive optical focal length, a fifth lens 5 with negative optical focal length, a sixth lens 6 with positive optical focal length, a seventh lens 7 with positive optical focal length, a galvanometer 8, a prism 9 and a photosensitive chip 10, which are arranged in sequence from the object side to the image side, so that the vehicle-mounted projection optical system can support an aperture of F1.7, and the total optical length is controlled within 64.2 mm.

[0032] In the technical solution provided by the present invention, a first lens 1 with negative optical power, a second lens 2 with negative optical power, a third lens 3 with negative optical power, a fourth lens 4 with positive optical power, a fifth lens 5 with negative optical power, a sixth lens 6 with positive optical power, a seventh lens 7 with positive optical power, a galvanometer 8, and a prism 9 are arranged in sequence from the object side to the image side. The large aperture of the first lens 1 can collect more light information under the same focal length, achieving a clear imaging effect in weak light and correcting axial chromatic aberration at the same time. The second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, and the seventh lens 7 can correct system chromatic aberration, spherical aberration, and image curvature, increase the system aperture, and ensure the imaging performance of the optical system at high temperatures without defocusing, so that the vehicle-mounted projection optical system can support an aperture of F1.7, and the total optical length is controlled within 64.2 mm, thereby providing a low-cost, high-temperature, non-defocused, large aperture, and compact vehicle-mounted projection optical system.

[0033] It should be noted that optical power is equal to the difference between the image-side and object-side beam convergence, and it characterizes the optical system's ability to deflect light. The first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, and the seventh lens 7 are capable of projecting light beams in a desired direction.

[0034] Specifically, in this embodiment, the optical power of the first lens 1 is φ1, the optical power of the second lens 2 is φ2, the optical power of the third lens 3 is φ3, the optical power of the fourth lens 4 is φ4, the optical power of the fifth lens 5 is φ5, the optical power of the sixth lens 6 is φ6, and the optical power of the seventh lens 7 is φ7. The vehicle-mounted projection optical system meets the following conditions:

[0035] and and and and and and

[0036] Specifically, in this embodiment, the first lens 1 and the seventh lens 7 are aspherical lenses, and the surface shapes of the first lens 1 and the seventh lens 7 satisfy the formula:

[0037]

[0038] Where c is the curvature corresponding to the radius, y is the radial coordinate, k is the conic coefficient, and to represent the coefficients corresponding to the respective radial coordinates. It can be understood that the unit of y is the same as the unit of lens length. When the k coefficient is less than -1, the lens surface curve is a hyperbola; when the k coefficient is equal to -1, the lens surface curve is a parabola; when the k coefficient is between -1 and 0, the lens surface curve is an ellipse; when the k coefficient is equal to 0, the lens surface curve is a circle; when the k coefficient is greater than 0, the lens surface curve is an oblate circle.

[0039] It should be noted that the characteristic of aspherical lenses is that their curvature changes continuously from the center of the lens to the periphery. Unlike spherical lenses, which have a constant curvature from the center to the periphery, aspherical lenses have a better curvature radius characteristic, which has the advantages of improving distortion and astigmatism. After using aspherical lenses, aberrations that occur during imaging can be eliminated as much as possible, thereby improving the imaging quality of the lens. In this way, the use of aspherical lenses can not only correct images and solve problems such as field of view distortion, but also make the lenses lighter, thinner, flatter, and maintain excellent impact resistance.

[0040] Specifically, in this embodiment, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are spherical lenses. By providing spherical lenses, while ensuring image quality and reliability, assembly sensitivity is reduced, thereby improving the yield rate of finished products.

[0041] Furthermore, in existing vehicle-mounted projection optical systems of the same type, plastic aspheric surfaces are used to achieve confocality and control costs. This results in poor lens reliability and inability to adapt to environments with large temperature fluctuations. To ensure the stability of the vehicle-mounted projection optical system while also balancing cost considerations, in this embodiment, the first lens 1 is made of plastic due to its strong impact resistance, light weight, and low cost. However, because plastic materials are chemically unstable when affected by ambient temperature, their refractive index is weaker than that of all-glass lenses, resulting in inferior image reproduction compared to glass lenses. To ensure the stability of the vehicle-mounted projection optical system under temperature fluctuations, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 are made of glass. Because glass lenses are less susceptible to thermal expansion and contraction, resulting in focus shifts, they can effectively resist thermal deformation and maintain high lens precision over time. The vehicle-mounted projection optical system utilizes a glass-plastic hybrid material, which not only saves costs and provides strong impact resistance, but also ensures system stability and high and low temperature compatibility.

[0042] Specifically, in this embodiment, the seventh lens element 7 is made of a low-softening glass. Low-softening glass is typically glass with an alkali metal or alkaline earth metal added, or with a forming material such as B2O3 or P2O5 added to lower the glass's softening point. Using softened glass is suitable for precision molding, extending mold life and reducing production costs.

[0043] In this way, by rationally designing the optical parameters and materials of each lens, the vehicle-mounted projection optical system is prevented from being out of focus in a high-temperature environment, ensuring clear resolution. The system uses a plastic material with extremely low water absorption while fully considering the changes in the refractive index and Abbe number of various lens materials at high and low temperatures, matching the surface shape and the change in air spacing, achieving positive and negative matching of the changes in the high and low temperature and humidity factors, and ensuring the synchronization and clarity of the image plane in high and low temperature and different humidity environments.

[0044] Furthermore, to improve imaging quality, in this embodiment, an aperture 11 is provided between the fourth lens element 4 and the fifth lens element 5. The aperture 11 limits the aperture of the on-axis light beam and blocks some light during zooming, thereby reducing light spots, increasing image contrast, and helping to improve image quality.

[0045] Furthermore, in this embodiment, the vehicle-mounted projection optical system further includes a protective glass 12 , and the protective glass 12 is disposed between the seventh lens 7 and the photosensitive chip 10 .

[0046] Specifically, the surface of the photosensitive chip 10 facing the object side is the imaging surface, that is, it can be the surface of a camera element such as a CCD or CMOS. It can be understood that the light carrying the information of the object can pass through the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the galvanometer 8 and the prism 9 in sequence, and finally form an image on the imaging surface.

[0047] It should be noted that when the aperture number supported by the vehicle-mounted projection optical system is F1.7, the operating distance is 0.74m, and the magnification is 95.8 times, the basic parameter table is shown in Table 1, where the units of curvature radius and thickness are both millimeters (mm).

[0048] Table 1

[0049]

[0050]

[0051] The aspheric coefficients of the first lens and the seventh lens are shown in the following table:

[0052] Table 2 Coefficients of the first surface S1 of the first lens

[0053] S1 k 1.122151 a1 0 a2 0.0013149064 a3 -3.1584965e-005 a4 6.1154119e-007 a5 -7.3669325e-009 a6 4.0402583e-011 a7 4.3086764e-014 a8 -1.008754e-015

[0054] Table 3 Coefficients of the second surface S2 of the first lens

[0055]

[0056]

[0057] Table 4 Coefficients of the first surface S13 of the seventh lens

[0058] S2 k -2.157682 a1 0 a2 -7.6870038e-006 a3 7.0737527e-008 a4 1.6159394e-010 a5 -2.1938971e-010 a6 7.2626139e-012 a7 -9.1557073e-014 a8 4.1459458e-016

[0059] Table 5 Coefficients of the second surface S14 of the seventh lens

[0060] S2 k -1.610618 a1 0 a2 4.3601572e-006 a3 3.0062353e-007 a4 -2.0821641e-008 a5 4.0865372e-010 a6 -3.185758e-012 a7 1.3421287e-015 a8 7.2513745e-017

[0061] Figure 2 is the MTF curve of the vehicle-mounted projection optical system in the visible light band; wherein the abscissa is the spatial frequency and the ordinate is the contrast; TSDiff.Limit is the diffraction limit in the meridional and sagittal directions, and TS 0.00 (deg) represents the diffraction curve in the meridional and sagittal directions at a field of view of 0.00 on the image plane.

[0062] Figure 3This is a defocus curve diagram of the vehicle-mounted projection optical system in the visible light band at an ambient temperature of 20°C. The horizontal axis represents the defocus amount in millimeters, and the vertical axis represents the contrast. TS 0.00 (deg) represents the diffraction curve in the meridian and sagittal directions at a field of view of 0.00 on the image plane.

[0063] Depend on Figure 2 and Figure 3 It can be seen that the MTF of the field of view at the center (0, 0) of the visible light band of the vehicle-mounted projection optical system in this embodiment can be close to 0.8, the defocus curve is concentrated, and the resolution is high.

[0064] The present invention also provides a motor vehicle, which includes the above-mentioned vehicle-mounted projection optical system. Since the motor vehicle includes the vehicle-mounted projection optical system, the specific structure of the vehicle-mounted projection optical system refers to the above-mentioned embodiment. Since the vehicle-mounted projection optical system of this motor vehicle adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0065] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A vehicle-mounted projection optical system, characterized in that: The vehicle-mounted projection optical system has an object side and an image side arranged opposite to each other along an optical axis. The vehicle-mounted projection optical system includes, arranged in order from the object side to the image side, a first lens with negative optical power, a second lens with negative optical power, a third lens with negative optical power, a fourth lens with positive optical power, a fifth lens with negative optical power, a sixth lens with positive optical power, a seventh lens with positive optical power, a galvanometer mirror, a prism, and a photosensitive chip, so that the vehicle-mounted projection optical system can support an aperture of F1.7 and a total optical length is controlled within 64.2 mm. The optical power of the first lens is The optical power of the second lens is The optical power of the third lens is The optical power of the fourth lens is The optical power of the fifth lens is The optical power of the sixth lens is The optical power of the seventh lens is The vehicle-mounted projection optical system meets the following conditions: and and and and and and 2. The vehicle-mounted projection optical system according to claim 1, wherein: The first lens and the seventh lens are aspherical lenses, and the surface shapes of the first lens and the seventh lens satisfy the formula: Wherein, c is the curvature corresponding to the radius, y is the radial coordinate, k is the conic quadratic curve coefficient, and a1 to a8 represent the coefficients corresponding to each radial coordinate, respectively.

3. The vehicle-mounted projection optical system according to claim 1, wherein: The second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are spherical lenses.

4. The vehicle-mounted projection optical system according to claim 1, wherein: The first lens is made of plastic.

5. The vehicle-mounted projection optical system according to claim 1, wherein: The second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are made of glass.

6. The vehicle-mounted projection optical system according to claim 1, wherein: The seventh lens is made of low-softening glass.

7. The vehicle-mounted projection optical system according to claim 1, wherein: A stop is provided between the fourth lens and the fifth lens.

8. The vehicle-mounted projection optical system according to claim 1, wherein: The vehicle-mounted projection optical system further includes a protective glass, which is disposed between the seventh lens and the photosensitive chip.

9. A motor vehicle, characterized in that: The vehicle-mounted projection optical system comprises the vehicle-mounted projection optical system according to any one of claims 1 to 8.

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