Optical lens with high efficiency and high image quality resolution

Abstract

The invention relates to an optical lens with high efficiency and high image quality resolution. The optical lens comprises a first lens, a second lens, a third lens, a fourth lens and an image surface which are arranged in sequence, wherein the first lens, the third lens and the fourth lens have positive focal power, and the second lens has negative focal power; the Abbe coefficient of the second lens is lower than that of the other three lenses; the first surface and the second surface of the second lens are bent towards one side far away from the image surface; the aperture diaphragm is arranged on the second lens or between the second lens and the object plane; and the vignetting diaphragm is arranged on the third lens or the fourth lens or between the third lens and the fourth lens. In the embodiment, the aperture diaphragm can limit the clear aperture of the system, so that the illumination efficiency is high; a vignetting diaphragm arranged on the third lens or the fourth lens or between the third lens and the fourth lens improves the image quality by limiting the clear aperture of the large view field; and the optical aberration of the system is corrected and optimized by combining four lenses.

Description

Technical Field

[0001] The invention relates to the field of optical design, and in particular to an optical lens with high efficiency and high image quality resolution. Background Art

[0002] Traditional headlight devices can provide good lighting at night, but when a vehicle appears in the opposite or same direction in front of the driver, it may cause dazzle to the other driver, posing a safety hazard.

[0003] Pixelated lighting fixtures can solve the above problems, mainly by identifying the position of the vehicle in front and shielding the vehicle position to avoid glare, while the area outside the vehicle in front is still well illuminated. The higher the resolution of the pixelated lighting device, the more accurately it can shield the area in front of the vehicle, making the lighting range outside the shielded area larger, and the surrounding Figure 1 It can be seen that Figure 1 When the pixels of the left segmentation are large, the obstacle is not illuminated. Figure 1 When the pixels segmented on the right are small, obstacles can be illuminated and driving is safer. Therefore, the pixel resolution is high and the lighting area can avoid more potential risks, providing safer driving at night.

[0004] High-resolution pixelated lighting devices are different from traditional lighting devices for car lights. They not only need to provide efficient lighting efficiency, but also need to take into account clear image resolution. Therefore, a lens group is needed to optimize and reduce various optical aberrations, such as distortion, spherical aberration, field curvature, etc., to obtain better image quality. Usually, a lens group with a smaller aperture can well optimize the optical aberration of the system, but a lens group with a smaller aperture cannot provide high lighting efficiency; a larger aperture has high lighting efficiency, but usually requires 5 or more lenses to correct aberrations, which makes the cost higher. Summary of the invention

[0005] Based on this, it is necessary to provide an optical lens with high efficiency and high image resolution to address at least some of the above problems.

[0006] An optical lens with high efficiency and high image quality resolution, comprising:

[0007] A first lens, a second lens, a third lens, a fourth lens and an image plane are arranged in sequence, wherein a side of each lens away from the image plane is a first surface, and a side close to the image plane is a second surface;

[0008] The first lens, the third lens and the fourth lens have positive optical power, and the second lens has negative optical power;

[0009] The Abbe coefficient of the second lens is lower than that of the other three lenses;

[0010] and the first surface and the second surface of the second lens are both curved toward a side away from the image plane;

[0011] An aperture stop is provided at the first lens, the second lens, or a position between the first lens and the second lens;

[0012] a vignetting stop, disposed at the third lens element or the fourth lens element or at a position between the third lens element and the fourth lens element;

[0013] The optical lens has a light exit aperture Z1 of the central field of view on the first surface of the first lens that is greater than 70% of the light aperture L1 of the surface, and a light exit aperture B1 of the edge field of view on the first surface of the first lens that is greater than 50% of the light aperture L1 of the surface;

[0014] The ratio of the clear aperture L4 of the second surface of the fourth lens facing the image plane to the back focus J1 of the lens group is greater than 2, and the light collection half angle α is greater than 35°.

[0015] In some embodiments, the aperture stop is disposed on a surface of the first lens or the second lens.

[0016] In some embodiments, the aperture stop is disposed on a surface of the first lens that is close to the image plane.

[0017] In some embodiments, the refractive index of the fourth lens is greater than the refractive index of the third lens.

[0018] In some embodiments, the surfaces of the first lens and the second lens are spherical or aspherical, and the surfaces of the third lens and the fourth lens are spherical.

[0019] In some embodiments, a distance L between a first surface of the first lens facing away from the image plane and the image plane does not exceed 80 mm.

[0020] In some embodiments, the half field of view FOV of the lens group is greater than 10.5°, and the aperture of the first lens ranges from 40 to 60 mm.

[0021] The above optical lens with high efficiency and high image resolution has at least the following beneficial technical effects:

[0022] The present invention provides a four-piece low-cost lens group design that combines high optical efficiency and good image quality under a large aperture.

[0023] In this embodiment, the aperture stop can limit the system aperture, the light exit aperture Z1 of the central field of view of the lens group on the first surface of the first lens is greater than 70% of the light exit aperture L1 of the surface, and the light exit aperture B1 of the edge field of view on the first surface of the first lens is greater than 50% of the light exit aperture L1 of the surface, so the lighting efficiency is high;

[0024] The ratio of the clear aperture L4 of the second surface of the fourth lens facing the image plane to the back intercept J1 of the lens group is greater than 2, so that the lens group can have a larger light collection angle (half angle α is greater than 35°) for the light source located at the image plane 50, thereby obtaining good lighting efficiency;

[0025] Since the nighttime lighting in the middle of the road is more demanding than that on both sides of the road, the lighting requirements for the central field of view of the lens group are higher, while the lighting brightness of the edge field of view can be reduced. Therefore, the vignetting stop provided in the third lens or the fourth lens or between the third lens and the fourth lens in this application improves the image quality by limiting the aperture of the edge field of view. In combination with the four lenses, the optical aberrations of the system, such as distortion, spherical aberration, and field curvature, are corrected and optimized to obtain better image quality.

[0026] The pixelated lighting device of the present application has high resolution and can more accurately shield the vehicle area in front, so that the lighting range outside the shielded area is larger. When the divided pixels are small, obstacles can be illuminated and driving is safer. Therefore, the pixel resolution is high and the lighting area can avoid more potential risks, providing safer driving at night. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram showing the comparison between the degree of pixel segmentation and the degree of illumination of obstacles;

[0028] Figure 2 A schematic diagram of an optical lens with high efficiency and high image resolution provided by an embodiment of the present invention;

[0029] Figure 3 for Figure 2 A schematic diagram of an aperture stop and a vignetting stop and a total length L of an optical lens having high efficiency and high image resolution;

[0030] Figure 4 Schematic diagram of the light aperture L1 of the first surface of the first lens and the light exit aperture Z1 of the central field of view;

[0031] Figure 5 Schematic diagram of the light aperture L1 of the first surface of the first lens and the light exit aperture B1 of the edge field of view;

[0032] Figure 6 Schematic diagram of the second surface clear aperture L4 of the fourth lens and the back intercept J1 of the lens group;

[0033] Figure 7 is a schematic diagram of the angle α of light rays collected in the central field of view of this embodiment;

[0034] Figure 8 Schematic diagram of MTF of this embodiment (0-12.5lp / mm);

[0035] Fig. 9Schematic diagram of MTF of this embodiment (0-8lp / mm);

[0036] Fig.10 is a distortion diagram of this embodiment;

[0037] In the figure,

[0038] 10. The first lens;

[0039] 20. Second lens;

[0040] 30. The third lens;

[0041] 40. The fourth lens;

[0042] 50. Image plane;

[0043] 60. Aperture diaphragm;

[0044] 70. Vignetting stop. DETAILED DESCRIPTION

[0045] The present invention will be further described below in conjunction with the accompanying drawings.

[0046] To facilitate understanding of the present invention, various embodiments defined by the claims of the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are given in the drawings, which contain various specific details to assist in this understanding, but these details should be regarded as exemplary only. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Accordingly, those of ordinary skill in the art will recognize that changes and improvements may be made to the various embodiments described herein without departing from the scope of the present invention defined by the appended claims. In addition, for the sake of clarity and brevity, descriptions of well-known functions and configurations may be omitted.

[0047] It will be apparent to those skilled in the art that the following description of various embodiments of the present invention is provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the appended claims.

[0048] Throughout the specification and claims of this application document, the words "include" and "comprise" and variations of the words, such as "include" and "include" mean "including but not limited to", and are not intended to (and will not) exclude other components, integers or steps. Features, integers or characteristics described in conjunction with a particular aspect, embodiment or example of the present invention will be understood to be applicable to any other aspect, embodiment or example described herein, unless incompatible therewith.

[0049] It should be understood that the singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise. The expressions "including" and / or "may include" used in the present invention are intended to indicate the presence of corresponding functions, operations, or elements, and are not intended to limit the presence of one or more functions, operations, and / or elements. In addition, in the present invention, the terms "including" and / or "having" are intended to indicate the presence of characteristics, quantities, operations, elements, and components, or combinations thereof, disclosed in the application documents. Therefore, the terms "including" and / or "having" should be understood as additional possibilities of one or more other characteristics, quantities, operations, elements, and components, or combinations thereof.

[0050] In the present invention, the expression "or" includes any or all combinations of the words listed together. For example, "A or B" may include A or B, or may include both A and B.

[0051] It should be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or there can also be an intervening element; when an element is considered to be "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or there can also be an intervening element.

[0052] The terms “upper”, “lower”, “left”, “right”, etc. mentioned in the text are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. It should also be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the context of the relevant field and this specification, and should not be interpreted in an idealized or overly formal sense unless explicitly defined as such herein. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0054] like Figure 2-Figure 3 As shown, in one embodiment of the present invention, there is provided an optical lens with high efficiency and high image resolution, comprising:

[0055] A first lens 10, a second lens 20, a third lens 30, a fourth lens 40 and an image plane 50 are arranged in sequence, and a side of each lens away from the image plane 50 is a first surface, and a side close to the image plane 50 is a second surface;

[0056] The first lens 10, the third lens 30 and the fourth lens 40 have positive focal power, and the second lens 20 has negative focal power. The focal power φ represents the refraction ability of the optical system to the incident parallel light beam. The larger the value of φ, the more the parallel light beam is refracted; when φ>0, the light refraction is convergent; when φ<0, the light refraction is divergent. When φ=0, it corresponds to plane refraction. At this time, the parallel light beam along the axis is still a parallel light beam along the axis after refraction, and no refraction phenomenon occurs;

[0057] The Abbe coefficient of the second lens 20 is lower than that of the other three lenses, and the first surface and the second surface of the second lens 20 are both curved toward a side away from the image plane 50;

[0058] An aperture stop 60 is provided at the first lens 10, the second lens 20, or a portion between the first lens 10 and the second lens 20;

[0059] a vignetting stop 70 , disposed at the third lens 30 or the fourth lens 40 or at a position between the third lens 30 and the fourth lens 40 ;

[0060] The optical lens has a light exit aperture Z1 of the central field of view on the first surface of the first lens that is greater than 70% of the light aperture L1 of the surface, and a light exit aperture B1 of the edge field of view on the first surface of the first lens that is greater than 50% of the light aperture L1 of the surface;

[0061] The ratio of the clear aperture L4 of the second surface of the fourth lens facing the image plane to the back focus J1 of the lens group is greater than 2.

[0062] The following table shows the lens group surface shape, position and material parameters of a set of lens group embodiments of the present invention:

[0063]

[0064] The expression of aspheric lens is as follows:

[0065]

[0066] Among them, z is the vector height at position r on the aspherical surface, c is the paraxial curvature of the aspherical surface, c=1 / r, r is the radius of curvature, k is the cone coefficient, and A~J are high-order coefficients.

[0067] The following table shows the aspheric surface parameters:

[0068]

[0069] In this embodiment, the aperture stop 60 of the system coincides with the second surface of the first lens 10, and the vignetting stop 70 coincides with the first surface of the fourth lens 40. The total length of the lens group in this embodiment is 62.9 mm.

[0070] The lens assembly of the present invention has a high energy collection rate for each field of view. The light angle (half angle) collected by the central field of view of the specific implementation example 1 is greater than 43 degrees (as shown in the attached Figure 7 ), so the lens group has a higher lighting efficiency. If a light source with a light-emitting angle of 2π is placed on the image plane 50, its energy utilization rate can also be greater than 40%.

[0071] The lens assembly of the present invention has good imaging quality. Figure 8 , the MTF of the specific implementation case is at 12.5lp / mm, the central field of view is greater than 0.85 (corresponding to the curve of the top 0deg in the implementation case), and the edge field of view (corresponding to the curve of the bottom 12deg in the implementation case) is greater than 0.55; reference Fig. 9 , MTF is at 8lp / mm, the center field of view is greater than 0.95, and the edge field of view is greater than 0.75.

[0072] MTF is a scientific method to evaluate the resolution of a lens. The closer it is to 1, the better the image quality. Figure 8 The curve corresponding to the center field of view (0deg) is closer to 1 than the curve corresponding to the edge field of view (12deg), that is, the resolution of the center field of view is higher. lp / mm refers to the number of light and dark line pairs that can be seen within 1mm. The higher the number of line pairs, the higher the resolution.

[0073] refer to Fig.10 , the distortion of the lens assembly described in the present invention is no more than 5%.

[0074] The present invention provides a four-piece low-cost lens group design that combines high optical efficiency and good image quality under a large aperture.

[0075] In this embodiment, the aperture stop 60 can limit the light aperture of the system. Figure 4 , Figure 5 The light-emitting aperture Z1 of the central field of view of the lens group on the first surface of the first lens 10 is larger than 70% of the light-transmitting aperture L1 of the surface, and the light-emitting aperture B1 of the edge field of view on the first surface of the first lens 10 is larger than 50% of the light-transmitting aperture L1 of the surface, so the lighting efficiency is high;

[0076] refer to Figure 6 The ratio of the light-clearance diameter L4 (diameter of the light-clearance area) of the second surface of the fourth lens 40 close to the image plane 50 to the back focus J1 of the lens group (the distance between the center of the second surface of the fourth lens 40 close to the image plane 50 and the image plane 50) is greater than 2, which enables the lens group to have a larger light collection angle for the light source located at the image plane 50 (as shown in the figure, the half angle α is 43°), thereby obtaining good lighting efficiency.

[0077] Because the nighttime illumination in the middle of the road is higher than that on both sides of the road, the illumination requirement of the central field of view of the lens group is higher, while the illumination brightness of the edge field of view can be reduced. Therefore, the vignetting stop 70 provided in the third lens 30 or the fourth lens 40 or between the third lens 30 and the fourth lens 40 of the present application improves the image quality by limiting the aperture of the edge field of view, that is, the setting of the vignetting stop 70 of the present application improves the image quality by sacrificing the illumination of the edge field of view. In combination with the four lenses, the optical aberrations of the system, such as distortion, spherical aberration, field curvature, etc., are corrected and optimized to obtain better image quality.

[0078] The pixelated lighting device of the present application has high resolution and can more accurately shield the vehicle area in front, making the lighting range outside the shielded area larger. Figure 1 It can be seen that when the segmented pixels are small, obstacles can be illuminated and driving is safer. Therefore, with high pixel resolution, the illuminated area can avoid more potential risks and provide safer driving at night.

[0079] In some embodiments, the aperture stop 60 is disposed on the surface of the first lens 10 and the second lens 20. The aperture stop 60 is used to limit the aperture of the system. If it is disposed between the first lens 10 and the second lens 20 or between the first lens 10 and the object plane, an additional component for shielding light needs to be provided. However, when the aperture stop 60 is disposed on the lens surface, the area outside the lens aperture is not transparent. Therefore, the lens itself determines the aperture of the light, and no additional device is required, which can greatly save costs.

[0080] refer to Figure 3 In some embodiments, the aperture stop 60 is disposed on a surface of the first lens 10 close to the image plane 50. When the lens group is used in a vehicle lighting device, the image plane 50 is the position of the light source, and the light emitted by the light source passes through the fourth lens 40, the third lens 30, and the second lens 20 in sequence, and finally exits from the first lens 10. The aperture stop 60 is disposed on the surface of the first lens 10 close to the image plane 50 so that the aperture of each field of view in the first lens 10 is as large as possible, that is, more light is emitted, thereby obtaining a higher lighting efficiency.

[0081] Referring to the figure, in some embodiments, the refractive index of the fourth lens 40 is greater than the refractive index of the third lens 30. When the lens group is used for vehicle lighting, the light source is set at the image plane 50 of the lens group, and the fourth lens 40 is closer to the light source. The light emitted by the light source preferentially passes through the fourth lens 40. The high refractive index has a stronger deflection energy for the light, and more energy emitted by the light source can be collected into the lens group, making the lighting efficiency of the lens group higher. Therefore, it is preferred to apply a material with a higher refractive index than the third lens 30 to the fourth lens 40.

[0082] In some embodiments, the surfaces of the first lens 10 and the second lens 20 may be spherical or aspherical, and the surfaces of the third lens 30 and the fourth lens 40 are spherical. Since the third lens and the fourth lens are made of glass, and the processing cost of a glass spherical surface is much lower than that of an aspherical surface, the use of a spherical design can reduce costs, and thus the lens assembly of the present invention can have better cost control.

[0083] In some embodiments, the refractive index and Abbe coefficient of the material of the first lens, the second lens, the third lens, and the fourth lens are all different. Lenses of materials with different characteristics cooperate with each other to adjust to reduce chromatic aberration, and through actual tests, four lenses with different Abbe coefficients can better balance the chromatic aberration of the lens group.

[0084] In some embodiments, an anti-reflection film may be provided on part or all of the surfaces of the first lens 10, the second lens 20, the third lens 30, and the fourth lens 40. The anti-reflection film reduces the energy loss caused by Fresnel reflection when light passes through the lens surface, thereby improving the lighting efficiency of the system.

[0085] refer to Figure 3 In some embodiments, the distance L between the first surface of the first lens 10 away from the image plane 50 and the image plane 50 does not exceed 80 mm, preferably, is less than 65 mm. Compared with the traditional lighting optical system, it has a smaller depth and is more advantageous for being arranged in a lamp with limited space.

[0086] In some embodiments, the half field of view FOV of the lens group is greater than 10.5°. The lens group of the present invention has a wider field of view FOV, and the half FOV of the implementation case is 12 degrees, which makes the range of illumination larger and improves driving safety. The lighting device equipped with the lens group can provide more lighting to one side of the curve when the vehicle enters a curve to improve driving safety. The larger FOV provided by the lens group means a larger range of providing more lighting to the curve.

[0087] In some embodiments, the aperture of the first lens 10 is in the range of 40 to 60 mm. If the aperture is less than 40 mm, a higher system lighting effect cannot be obtained, and if the aperture is greater than 60 mm, the lens group is unable to obtain a better image resolution.

[0088] A light emitting component comprises a light source and any one of the above-mentioned optical lenses with high efficiency and high image resolution, wherein the light source is disposed on an image plane 50 .

[0089] A vehicle comprises a vehicle body and the light-emitting component, wherein the light-emitting component is arranged on the vehicle body.

[0090] In the above description, although expressions such as "first" and "second" may be used to describe various elements of the present invention, they are not intended to limit the corresponding elements. For example, the above expressions are not intended to limit the order or importance of the corresponding elements. The above expressions are used to distinguish one component from another component.

[0091] The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. A singular expression includes a plural expression unless there is a significant difference in context or scheme therebetween.

[0092] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.

[0093] Those skilled in the art will understand that the various technical features of the above-described embodiments may be omitted, added or combined in any manner accordingly. To make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, and the simple transformation methods that can be thought of by those skilled in the art and the solutions for making adaptive and functional structural transformations to the prior art should be considered to be within the scope of this specification.

[0094] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that although the present invention has been shown and described with reference to various embodiments, for ordinary technicians in the field, various deformations and improvements in several forms and details can be made without departing from the concept of the present invention, and without departing from the scope of the present invention defined by the attached claims, all of which belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. An optical lens with high efficiency and high image resolution, characterized in that: include: A first lens, a second lens, a third lens, a fourth lens and an image plane are arranged in sequence, wherein a side of each lens away from the image plane is a first surface, and a side close to the image plane is a second surface; The first lens, the third lens and the fourth lens have positive optical power, and the second lens has negative optical power; The Abbe coefficient of the second lens is lower than that of the other three lenses; and the first surface and the second surface of the second lens are both curved toward a side away from the image plane; An aperture stop is provided at the first lens, the second lens, or a position between the first lens and the second lens; a vignetting stop, disposed at the third lens element or the fourth lens element or at a position between the third lens element and the fourth lens element; The optical lens has a light exit aperture Z1 of the central field of view on the first surface of the first lens that is greater than 70% of the light aperture L1 of the surface, and a light exit aperture B1 of the edge field of view on the first surface of the first lens that is greater than 50% of the light aperture L1 of the surface; The ratio of the clear aperture L4 of the second surface of the fourth lens facing the image plane to the back focus J1 of the lens group is greater than 2, and the light collection half angle α is greater than 35°.

2. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: The aperture stop is arranged on the surface of the first lens or the second lens.

3. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: The aperture stop is arranged on a surface of the first lens close to the image plane.

4. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: The refractive index of the fourth lens is greater than the refractive index of the third lens.

5. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: The surfaces of the first lens and the second lens are spherical or aspherical, and the surfaces of the third lens and the fourth lens are spherical.

6. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: A distance L between a first surface of the first lens facing away from the image plane and the image plane does not exceed 80 mm.

7. The optical lens with high efficiency and high image resolution according to claim 1, characterized in that: The half field of view FOV of the lens group is greater than 10.5°, and the aperture range of the first lens is 40 to 60 mm.

8. A light emitting component, characterized in that: It comprises a light source and an optical lens with high efficiency and high image resolution as described in any one of claims 1 to 7, wherein the light source is arranged on the image plane.

9. A vehicle, characterized in that: It comprises a vehicle body and the light-emitting assembly as claimed in claim 8, wherein the light-emitting assembly is arranged on the vehicle body.

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