CN111561682A - Automobile headlamp lens and design method thereof - Google Patents

Automobile headlamp lens and design method thereof Download PDF

Info

Publication number
CN111561682A
CN111561682A CN202010420028.6A CN202010420028A CN111561682A CN 111561682 A CN111561682 A CN 111561682A CN 202010420028 A CN202010420028 A CN 202010420028A CN 111561682 A CN111561682 A CN 111561682A
Authority
CN
China
Prior art keywords
lens
zone
optical surface
diffractive
diffraction zone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010420028.6A
Other languages
Chinese (zh)
Inventor
江程
南基学
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yejia Optical Technology Guangdong Corp
Original Assignee
Yejia Optical Technology Guangdong Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yejia Optical Technology Guangdong Corp filed Critical Yejia Optical Technology Guangdong Corp
Priority to CN202010420028.6A priority Critical patent/CN111561682A/en
Publication of CN111561682A publication Critical patent/CN111561682A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S41/00—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps
    • F21S41/20—Illuminating devices specially adapted for vehicle exteriors, e.g. headlamps characterised by refractors, transparent cover plates, light guides or filters
    • F21S41/25—Projection lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0012—Optical design, e.g. procedures, algorithms, optimisation routines
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2102/00—Exterior vehicle lighting devices for illuminating purposes
    • F21W2102/10—Arrangement or contour of the emitted light
    • F21W2102/13—Arrangement or contour of the emitted light for high-beam region or low-beam region
    • F21W2102/135—Arrangement or contour of the emitted light for high-beam region or low-beam region the light having cut-off lines, i.e. clear borderlines between emitted regions and dark regions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21W—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO USES OR APPLICATIONS OF LIGHTING DEVICES OR SYSTEMS
    • F21W2107/00—Use or application of lighting devices on or in particular types of vehicles
    • F21W2107/10—Use or application of lighting devices on or in particular types of vehicles for land vehicles

Abstract

The invention provides a vehicle headlight lens and its design method, two surfaces of the lens body are respectively a refraction optical surface and a base surface, the base surface is provided with a diffraction optical surface, the diffraction optical surface comprises an outer diffraction zone and an inner diffraction zone which are concentrically arranged, the inner radius and the outer radius of the outer diffraction zone are kr respectivelymaxAnd rmaxRadius of the inner diffraction zone is krmax(ii) a The focal length of the lens body in the range of the outer diffraction zone is f1The focal length of the lens body in the range of the inner diffraction zone is f2The outer diffraction zone satisfies the phase modulation function:
Figure DDA0002496516450000011
the inner diffractive zone satisfies the phase modulation function:
Figure DDA0002496516450000012
the composite refractive optical surface and the diffractive optical surface can remarkably improve the dispersion performance, and the bifocal structure can effectively reduce the sensitivity to axial tolerance during assembly, can effectively reduce the assembly cost, and can effectively regulate and control the gradient value of a light and shade cut-off line.

Description

Automobile headlamp lens and design method thereof
Technical Field
The invention relates to a vehicle lamp lens, and particularly discloses an automobile headlamp lens and a design method thereof.
Background
By automotive headlamp lens is meant a lens structure for an automotive headlamp system, which typically comprises a light source, a light energy collecting element, a cut-off stop and a refractive lens, as shown in fig. 1. The refraction lens is used for imaging the light and dark cut-off line structure, so that the formed light spot meets the requirement of light intensity distribution of the dipped headlight, the cut-off line baffle is one of the light and dark cut-off line structures, and the cut-off line baffle can also adopt a part which is compounded with the structural member and has a shape similar to the light and dark cut-off line.
The car light lens is an optical part for energy distribution conversion, and from the perspective of imaging optics, the car light lens is an optical imaging system with a large numerical aperture, namely the F # of a lens is small and is generally less than 1.0, and the position-variable image of a near field is converted into an angle-variable image corresponding to a far field, so that the requirement on the utilization rate of energy is high. In an automotive headlamp system, in order to meet the cost requirement, a single-chip refractive lens is generally adopted for implementation.
The lighting standard of the automobile headlamp has a requirement on the gradient value of a cut-off line of a light and a shade, in the prior art, a single positive lens in an automobile headlamp system has negative chromatic aberration constantly, and when the system is actually applied, a test screen beyond 25m presents very obvious dispersive strip-shaped light spots, so that the requirement on the gradient value of the cut-off line is difficult to meet with high quality; in addition, in the prior art, the axial tolerance sensitivity of the automobile headlamp system is high, and because the cut-off line blocking sheet in the automobile headlamp system is positioned at the focus of the lens, a bright and dark cut-off line image is formed at a far distance, and according to the Newton formula f′The focal length is fixed, once the lens takes a tiny position, the focal object distance x is changed from 0 to a finite size, the focal image distance x' of the image space is changed from an infinite value to a finite value, the front-back difference value is infinite, the displacement of the lens in the existing automobile headlamp system generally cannot exceed 0.5% of the focal length of the lens, and the assembly requirement is highAnd the assembly cost is high.
Disclosure of Invention
Therefore, it is necessary to provide an automotive headlamp lens and a design method thereof, which can significantly improve dispersion performance and effectively reduce sensitivity to axial tolerance during assembly and use, in order to solve the problems in the prior art.
In order to solve the problems of the prior art, the invention discloses an automobile headlamp lens which comprises a lens body, wherein two surfaces of the lens body are respectively a refractive optical surface and a base surface, a diffractive optical surface is arranged on the base surface, the diffractive optical surface comprises an annular outer diffraction area and a circular inner diffraction area which are concentrically arranged, and the radius of the lens body is rmaxThe inner radius and the outer radius of the outer diffraction zone are each krmaxAnd rmaxRadius of the inner diffraction zone is krmax，0<k<1；
The focal length of the lens body in the range of the outer diffraction zone is f1The focal length of the lens body in the range of the inner diffraction zone is f2，f1≠f2Refractive power of optical surface
Figure BDA0002496516430000021
Satisfies the following conditions:
Figure BDA0002496516430000022
υrabbe number, upsilon, of refractive optical surfacedIs the equivalent abbe number of the diffractive optical surface,
Figure BDA0002496516430000023
the total focal power, the focal power of the outer diffractive zone
Figure BDA0002496516430000024
Satisfies the following conditions:
Figure BDA0002496516430000025
focal power of inner diffraction zone
Figure BDA0002496516430000026
Satisfy the requirement of
Figure BDA0002496516430000027
The total optical power of the outer diffraction zone being
Figure BDA0002496516430000028
The total optical power of the inner diffraction zone is
Figure BDA0002496516430000029
The outer diffractive zones satisfy the phase modulation function:
Figure BDA00024965164300000210
the inner diffractive zone satisfies the phase modulation function:
Figure BDA00024965164300000211
n is the number of terms of the phase polynomial, r is the radius, Ai、BiAre all phase polynomial coefficients.
Further, the lens body is a PC lens, a PMMA lens or a glass lens.
Further, the refractive optical surface is a curved surface structure having positive optical power.
Further, the base surface is a plane or a curved surface.
Further, the diffractive optical surface is a diffractive microstructure having positive optical power.
The invention also discloses a design method of the automobile headlamp lens, which comprises the following steps:
s1, setting the integral equivalent focal length of the lens body to be f according to the requirement, setting the two surfaces of the lens body to be a refractive optical surface and a base surface respectively, setting a diffractive optical surface on the base surface, and setting the focal power of the refractive optical surface to be f
Figure BDA00024965164300000212
Satisfies the following conditions:
Figure BDA00024965164300000213
υrabbe number, upsilon, of refractive optical surfacedIs the equivalent abbe number of the diffractive optical surface,
Figure BDA00024965164300000214
is the total focal power;
s2, arranging the diffraction optical surface to comprise an outer diffraction zone and an inner diffraction zone which are in the same circle, wherein the inner radius of the outer diffraction zone is the same as the outer radius of the outer diffraction zone, and the outer radius of the outer diffraction zone is krmaxAnd rmaxThe inner diffraction zone is a ring structure with a radius of krmaxCircular structure of (1), 0<k<1；
S3, setting the outer diffraction zone and the inner diffraction zone to have different focuses F1And F2，F1And F2Total focal length f of the outer diffractive zone, offset by + - Δ f from the equivalent focal length f1Satisfies the following conditions: f. of1Total focal length f of inner diffraction zone ═ f + Δ f2Satisfies the following conditions: f. of2＝f-Δf；
S4, optical power of outer diffraction zone
Figure BDA00024965164300000215
Satisfies the following conditions:
Figure BDA00024965164300000216
focal power of inner diffraction zone
Figure BDA00024965164300000217
Satisfies the following conditions:
Figure BDA00024965164300000218
the total optical power of the outer diffraction zone being
Figure BDA00024965164300000219
The total optical power of the inner diffraction zone is
Figure BDA00024965164300000220
S5, the outer diffraction zone satisfies the phase modulation function:
Figure BDA00024965164300000221
the inner diffractive zone satisfies the phase modulation function:
Figure BDA00024965164300000222
n is the number of terms of the phase polynomial, r is the radius, Ai、BiAre all phase polynomial coefficients.
Further, the diffractive optical surface is a micro-lens structure composed of a plurality of concentric circular ring belts, and the radius r and the equivalent focal length f of the first circular ring belt satisfy the following conditions:
Figure BDA00024965164300000223
further, the power of the refractive optical surface
Figure BDA00024965164300000224
Satisfies the following conditions:
Figure BDA00024965164300000225
further, k is 0.5.
Further, the total focal length f of the outer diffractive zone1And total focal length f of the inner diffraction zone2Satisfies the following conditions: f. of1-f2≤0.02f。
The invention has the beneficial effects that: the invention discloses an automobile headlamp lens and a design method thereof, wherein a refraction optical surface and a diffraction optical surface are compounded on two surfaces of a lens body, so that the dispersion performance can be obviously improved, the sensitivity to axial tolerance when the lens is assembled and applied to an automobile headlamp system, namely the axial defocusing sensitivity, is effectively reduced by arranging a special bifocal structure, the assembly fault tolerance rate is high, the assembly requirement is relatively low, the assembly cost can be effectively reduced, the assembly efficiency is improved, in addition, the bifocal structure is matched with the lens with the compound surface structure, the gradient value of a light and shade cut-off line can be effectively regulated and controlled, and the gradient value requirement of the regulation standard on the light and shade cut-off line is effectively met.
Drawings
Fig. 1 is a schematic structural diagram of a conventional automotive headlamp system.
FIG. 2 is a schematic view of a lens structure according to the present invention.
Fig. 3 is an enlarged structural view of C in fig. 2 according to the present invention.
FIG. 4 is a schematic view of an optical path structure of the lens of the present invention assembled with a stop line stop plate.
Fig. 5 is a phase-radial plot of the phase modulation function of the present invention versus the rounding function and the Sag value.
Fig. 6 is a schematic view of an optical path structure when a refractive lens and a stop line stop sheet are assembled in the first embodiment of the present invention.
Fig. 7 is a schematic view of an optical path structure when the lens of the invention is assembled with the stop line stop plate in the first embodiment.
FIG. 8 is a graph of Sag value versus radial coordinate for the outer diffraction zone of the present invention.
FIG. 9 is a graph of Sag value versus radial coordinate for the inner diffraction zone of the present invention.
FIG. 10 is a graph of focus offset versus wavelength for a lens of the present invention compared to a conventional refractive lens.
The reference signs are: lens body 10, refractive optical surface 11, base surface 12, diffractive optical surface 13, outer diffractive region 131, inner diffractive region 132.
Detailed Description
For further understanding of the features and technical means of the present invention, as well as the specific objects and functions attained by the present invention, the present invention will be described in further detail with reference to the accompanying drawings and detailed description.
Refer to fig. 2 to 10.
The embodiment of the invention discloses an automobile headlamp lens, as shown in fig. 2 and 3, the automobile headlamp lens comprises a lens body 10, two surfaces of the lens body 10 are respectively a refractive optical surface 11 and a base surface 12, a diffractive optical surface 13 is arranged on the base surface 12, the maximum phase change value of the diffractive optical surface 13 is m lambda, preferably, the diffractive optical surface 13 is a micro-lens structure formed by a plurality of concentric circular ring belts, the diffractive optical surface 13 comprises a circular outer diffraction zone 131 and a circular inner diffraction zone 132 which are concentrically arranged, the circular outer diffraction zone 131 and the circular inner diffraction zone 132 have a common circle center, and the maximum caliber radius of the lens body 10 is rmaxThe inner radius and the outer radius of the outer diffraction region 131 are each krmaxAnd rmaxThe radius of the inner diffraction zone 132 is krmax，0<k<1；
The focal point of the lens body 10 in the range of the outer diffraction zone 131 is F1The focal point of the lens body 10 in the range of the inner diffraction zone 132 isF2，F1And F2Offset, focal length f of the lens body 10 within the outer diffractive zone 1311The focal length of the lens body 10 in the range of the inner diffraction zone 132 is f2，f1≠f2As shown in FIG. 4, it can be seen that there are two focal distances x corresponding to the ideal situation1And x2And the two focal object distances are not equal to 0, the corresponding image object distance is necessarily finite value according to the Newton formula, but not infinite of the common lens, when the stop line blocking piece and the lens are applied to an automobile headlamp system, the small stop line blocking piece is assembled, the small displacement of the small stop line blocking piece cannot cause huge change, the axial allowable tolerance is large, and the stop line blocking piece is arranged at F1And F2The method has the advantages of high fault tolerance rate of assembly, low assembly difficulty and focal power of the refractive optical surface 11
Figure BDA0002496516430000041
Satisfies the following conditions:
Figure BDA0002496516430000042
υrabbe number, upsilon, of refractive optical surface 11dIs the equivalent abbe number of the diffractive optical surface 13,
Figure BDA0002496516430000043
the power of the outer diffractive region 131 is the total power
Figure BDA0002496516430000044
Satisfies the following conditions:
Figure BDA0002496516430000045
the power of the inner diffractive zone 132
Figure BDA0002496516430000046
Satisfy the requirement of
Figure BDA0002496516430000047
Is well designed f1And f2The value of (a) is,
Figure BDA0002496516430000048
and
Figure BDA0002496516430000049
can be calculated by the power calculation formula, and the total power of the outer diffraction zone 131 is
Figure BDA00024965164300000410
The total optical power of the inner diffractive region 132 is
Figure BDA00024965164300000411
The outer diffractive region 131 satisfies the phase modulation function:
Figure BDA00024965164300000412
the inner diffractive region 132 satisfies the phase modulation function:
Figure BDA00024965164300000413
n is the number of terms of the phase polynomial, r is the radius, Ai、BiBoth are phase polynomial coefficients, and the surface profiles corresponding to the outer diffraction zone 131 and the inner diffraction zone 132 can be obtained from the two phase adjustment functions.
Through the compound refraction optical surface 11 in two surfaces of the lens body 10 and the diffraction optical surface 13, can effectively improve dispersion performance when being applied to the vehicle headlamps system, in addition, through the structure that sets up the bifocus, axial out-of-focus sensitivity when can effectively reduce lens assembly in the vehicle headlamps system, it is low to appear out-of-focus possibility during the assembly, and the assembly degree of difficulty is low, can effectively save assembly cost, improves assembly efficiency.
According to the requirement of the light distribution regulation of the automobile headlamp, the European standard ECE confirms that the cut-off line of the automobile headlamp must meet the requirement of a gradient value, namely the cut-off line cannot be too clear or too fuzzy. When the lens is applied to an automobile headlamp system, the lens which is compounded with the refraction optical surface 11 and the diffraction optical surface 13 is adopted, the chromatic aberration is small, the definition of a light and shade cut-off line can be improved from the aspect of visitation, the definition of an image surface can be reduced due to the existence of double focuses, so that the cut-off line is fuzzy, the gradient value can be reduced, and the gradient value can be effectively controlled due to the matching of the double focuses and the lens with the refraction and diffraction compound surface structure. The blurring of the cut-off line can be controlled by controlling the shift amount of the bifocal point.
In the present embodiment, the lens body 10 is a PC lens, a PMMA lens, or a glass lens.
In the present embodiment, the refractive optical surface 11 is a curved surface structure having positive optical power.
In the present embodiment, the base surface 12 is a plane or a curved surface.
In the present embodiment, the diffractive optical surface 13 is a diffractive microstructure having positive optical power.
The embodiment of the invention also discloses a design method of the automobile headlamp lens, which comprises the following steps:
s1, set up the holistic equivalent focal length of the lens body 10 as f according to the demand, the two sides that set up the lens body 10 are refraction optical surface 11 and basal plane 12 respectively, are provided with diffraction optical surface 13 on the basal plane 12, set up refraction optical surface 11 and diffraction optical surface 13 and satisfy:
Figure BDA00024965164300000414
the power of the refractive optical surface 11 can be calculated
Figure BDA00024965164300000415
Satisfies the following conditions:
Figure BDA00024965164300000416
initial power of diffractive optical surface 13
Figure BDA00024965164300000417
Satisfies the following conditions:
Figure BDA00024965164300000418
υrabbe number, upsilon, of refractive optical surface 11dIs the equivalent abbe number of the diffractive optical surface 13,
Figure BDA0002496516430000051
total focal power, total focal power
Figure BDA0002496516430000052
Passing through optical lensometerThe calculation formula is obtained by calculating according to the value of f;
s2, arranging the diffraction optical surface 13 to include an outer diffraction area 131 and an inner diffraction area 132 which are homocircular, wherein the inner radius and the outer radius of the outer diffraction area 131 are kr respectivelymaxAnd rmaxThe inner diffraction region 132 has a radius krmaxCircular structure of (1), 0<k<1；
S3, setting the outer diffraction zone 131 and the inner diffraction zone 132 to have different focal points F1And F2，F1And F2Is shifted by +/- Δ f relative to the equivalent focal length f, Δ f is a minute focal length shift, and the total focal length f of the lens body 10 in the range of the outer diffraction zone 1311Satisfies the following conditions: f. of1F + Δ f, total focal length f of lens body 10 within inner diffractive zone 1322Satisfies the following conditions: f. of2＝f-Δf；
S4, optical power of outer diffraction zone 131
Figure BDA0002496516430000053
Satisfies the following conditions:
Figure BDA0002496516430000054
the power of the inner diffractive zone 132
Figure BDA0002496516430000055
Satisfies the following conditions:
Figure BDA0002496516430000056
the total optical power of the lens body 10 in the range of the outer diffraction zone 131 is
Figure BDA0002496516430000057
The total optical power of the lens body 10 within the inner diffractive zone 132 is
Figure BDA0002496516430000058
According to a power calculation formula in combination with a known f1And f2Can be calculated to obtain
Figure BDA0002496516430000059
And
Figure BDA00024965164300000510
although the power of the outer diffractive region 131
Figure BDA00024965164300000511
And the power of the inner diffractive region 132
Figure BDA00024965164300000512
All deviate from the initial focal power
Figure BDA00024965164300000513
And the focal power of the refractive surface
Figure BDA00024965164300000514
The achromatic formula is not established due to invariance, but the deviation of focal power is a tiny amount, so the influence on chromatic aberration can be ignored, and in addition, an optical system of the automobile headlamp is not an imaging optical system in a strict sense and only needs to restrain chromatic dispersion within an acceptable range;
s5, r of diffractive optical surface<krmaxThen, the outer diffractive region 131 satisfies the following phase modulation function:
Figure BDA00024965164300000515
r of the diffractive optical surface is larger than or equal to krmaxThat is, the inner diffractive region 132 satisfies the phase modulation function:
Figure BDA00024965164300000516
n is the number of terms of the phase polynomial, r is the radius from the axis of the lens body 10, Ai、BiAll are phase polynomial coefficients, the focal power of the diffraction surface is determined by a 2-order coefficient, a diffraction order and a designed wavelength, and a phase modulation coefficient higher-order coefficient can be set to be 0 in the initial design, so that two different focal powers obtained by calculation in the previous step
Figure BDA00024965164300000517
And
Figure BDA00024965164300000518
respectively substitute for
Figure BDA00024965164300000519
And
Figure BDA00024965164300000520
can be calculated to obtain A2And B2Thus, the phase modulation function of the diffractive optical surface 13 is obtained, and is converted into height values, also called Sag values, of the diffractive optical surface 13 at each corresponding radial position according to the phase modulation function, as shown in fig. 5, the vertical axis represents the DOE phase with a wavelength of 550nm, the horizontal axis represents the radial coordinate, the continuous and smooth curve is a phase modulation function curve, i.e., a curve in which the phase changes with the radius, the step-shaped curve is an integer function curve of the phase modulation function, the tooth-shaped curve is a Sag value curve of the diffractive optical surface 13, and the value 1 of the vertical axis in the figure corresponds to the height of 550nm, and the microlens structure of the diffractive optical surface 13 is manufactured according to the Sag value curve, so that other aberrations can be effectively reduced by constantly optimizing the high-order term coefficient.
The refractive index of common optical materials decreases with increasing wavelength, which makes the single-chip positive optical lens designed by the principle of refraction have different focal powers for different wavelengths of light, short wavelength focal length and long wavelength focal length. Therefore, the focal powers of different wavelengths are different, imaging is a phenomenon that chromatic aberration is generated and expressed as chromatic dispersion, and the chromatic dispersion performance of a material is generally represented by an abbe number v. For example, the most commonly used injection molding resin material PMMA for a lens for a vehicle lamp has an abbe number v of 58, and another commonly used resin material PC has an abbe number v of 28. The smaller the number, the greater the dispersion of the material, and as can be seen from the above numbers, the dispersion of PC is worse than that of PMMA. When the single lens designed by the refraction principle is used for imaging, chromatic aberration cannot be eliminated.
For diffractive optical elements, dispersion is a result of the diffractive splitting action of the surface microstructure on light of different wavelengths, and the diffractive dispersion action is much stronger than for refractive elements. In addition, the dispersion of the diffractive element depends on the size of the surface microstructure, independently of the substrate material. For a diffractive lens with positive optical power, the longer the wavelength of the light, the smaller the focal length, and conversely, the shorter the wavelength, the longer the focal length. This is exactly the opposite of a normal refractive lens. This is one of the particularly interesting features of a diffractive element whose optical microstructure produces a dispersion of opposite sign to that produced by the material. The abbe number v is only relevant for the wavelength used, and in the visible range of automotive lamp applications, the equivalent abbe number of the diffractive optics is calculated similarly to the definition of the conventional abbe number in three typical wavelengths, i.e. 486.1nm for F light, 589.3nm for D light and 656.3nm for C light:
Figure BDA0002496516430000061
from these values, it can be seen that the abbe number of the diffraction optical element in the visible light range is always negative at-3.4, and when v of the resin material PC before comparison is 28 or when v of PMMA is 58, the opposite sign of the dispersion is more clearly seen, and chromatic aberration can be effectively eliminated by the refractive optical surface 11 and the diffractive optical surface 13 having positive and negative abbe numbers, respectively.
When the single-chip projection type headlamp is applied, the two surfaces of the lens are respectively designed into a refractive optical surface 11 and a diffractive optical surface 13 through the optical properties of the composite refractive lens and the diffractive lens, the maximum phase change values of the diffractive optical surface 13 are m lambda, lambda is the designed wavelength, and m is the corresponding diffraction order.
Aiming at defocusing sensitivity in an automobile headlamp system, the robustness of the system is enhanced by designing a bifocal mode. The distance between the two foci can equivalently be considered as the diffuse spot of the paraxial equivalent focus of the lens. As shown in FIG. 4, it can be seen that the ideal situation corresponds to two focal object distances x1And x2Not equal to 0, according to Newton formula, the corresponding image object distance is necessarily finite value, but not infinite of general lens, thereby tiny displacement of tiny cut-off line baffle structure can not cause huge change, thereby increasing tolerance allowed by axial direction.
In addition, the definition of the image plane is inevitably reduced due to the double focal points. For the requirement of the light distribution regulation of the automobile headlamp, the European standard ECE confirms that the cut-off line of the automobile headlamp must meet the requirement of the Gradient value. In general, the cut-off line cannot be too clear or too blurred. The traditional technology meets the gradient requirement by adding an orange peel surface or micro-structural atomization to the light-emitting surface. The invention adopts the lens with the refraction and diffraction compound surface structure, so that the chromatic aberration is reduced, and the definition of a light and shade cut-off line is improved in the aspect of visitation. By designing the compound refraction and diffraction lens and the bifocal mode, the image plane definition can be reduced, the cut-off line is blurred, and the gradient value is reduced. By controlling the amount of shift of the bifocal point, the degree of blurring of the cut-off line can be controlled.
In this embodiment, in step S1, the diffractive optical surface 13 is a microlens structure composed of several concentric circular ring zones, and the radius r of the first circular ring zone and the equivalent focal length f satisfy:
Figure BDA0002496516430000062
in the present embodiment, in step S1, the refractive power of the refractive optical surface 11
Figure BDA0002496516430000063
Satisfies the following conditions:
Figure BDA0002496516430000064
in this embodiment, in step S2, k is 0.5, that is, the radius of the inner diffraction region 132 is 0.5rmaxThe inner radius of the outer diffraction region 131 is 0.5rmaxAs shown in fig. 4, the energy at different focal powers of the diffractive optical surface 13 is substantially similar, and the k value can also be measured by simulation or calculation to determine the boundary line where half of the light energy is located.
In the present embodiment, in step S3, the total focal length f of the outer diffraction zone 1311And the total focal length f of the inner diffractive zone 1322Satisfies the following conditions: f. of1-f2Less than or equal to 0.02f, namely 2 delta f is less than or equal to 0.02 f.
The lens body 10 is manufactured by using PMMA, and a refractive lens in the prior art is used as a prototype to design an equivalent focal length f of 61mm and a radius r of a maximum aperturemax70mm as shown in figure 6. According to the solution of the invention it is possible to obtain a vehicle headlamp lens as shown in the figures,as shown in FIG. 7, the total focal length f of the lens body 10 in the region of a radius of not less than 17.5mm161.6mm, the total focal length f of the lens body in the region of a radius of less than 17.5mm260.5 mm. The phase modulation function of the outer diffractive region 131 is
Figure BDA0002496516430000071
The phase modulation function of the inner diffractive region 132 is
Figure BDA0002496516430000072
The Sag values of the outer diffraction regions 131 and the Sag values of the inner diffraction regions 132 are shown in fig. 8 and 9, respectively.
The curve of the focus offset versus the wavelength of the lens of the invention obtained in the first comparative example and the refractive lens of the prior art is shown in fig. 10, wherein the vertical axis represents the focus offset, specifically the axial focus offset, the on-axis focus offset represents the magnitude of the axial chromatic aberration, and the horizontal axis represents the wavelength of light, and the on-axis chromatic aberration (F light — C light) of the refractive lens of the prior art, which can be obtained according to fig. 10, is about-1.0 mm, while the on-axis chromatic aberration of the lens of the invention is only-0.2 mm, which obviously shows that the lens of the automotive headlamp manufactured by the invention greatly reduces the chromatic aberration and improves the color effect.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The automobile headlamp lens is characterized by comprising a lens body (10), wherein two surfaces of the lens body (10) are respectively a refractive optical surface (11) and a base surface (12), a diffractive optical surface (13) is arranged on the base surface (12), the diffractive optical surface (13) comprises an annular outer diffraction zone (131) and a circular inner diffraction zone (132) which are concentrically arranged, and the radius of the lens body (10) is rmaxExternal derivativeThe inner radius and the outer radius of the radiation region (131) are krmaxAnd rmaxThe radius of the inner diffraction zone (132) is krmax，0<k<1；
The focal length of the lens body (10) within the outer diffraction zone (131) is f1The focal length of the lens body (10) in the range of the inner diffraction zone (132) is f2，f1≠f2The power of the refractive optical surface (11)
Figure FDA0002496516420000013
Satisfies the following conditions:
Figure FDA0002496516420000014
υris Abbe number, upsilon, of the refractive optical surface (11)dIs an equivalent Abbe number of the diffractive optical surface (13),
Figure FDA00024965164200000113
the power of the outer diffraction zone (131) being the total power
Figure FDA0002496516420000015
Satisfies the following conditions:
Figure FDA0002496516420000016
the power of the inner diffractive zone (132)
Figure FDA0002496516420000017
Satisfy the requirement of
Figure FDA0002496516420000018
The total optical power of the outer diffraction zone (131) is
Figure FDA00024965164200000114
The total optical power of the inner diffraction zone (132) is
Figure FDA0002496516420000019
The outer diffractive zones (131) satisfy a phase modulation function:
Figure FDA0002496516420000011
the inner diffractive zone (132) satisfies a phase modulation function:
Figure FDA0002496516420000012
n is the number of terms of the phase polynomial, r is the radius, Ai、BiAre all phase polynomial coefficients.
2. Automotive headlamp lens according to claim 1, wherein the lens body (10) is a PC lens, a PMMA lens or a glass lens.
3. A vehicle headlight lens according to claim 1, wherein the refractive optical surface (11) is a curved surface structure having a positive optical power.
4. A vehicle headlight lens according to claim 3, wherein the base surface (12) is plane or curved.
5. The vehicle headlamp lens according to claim 3 or 4, wherein the diffractive optical surface (13) is a diffractive microstructure having a positive optical power.
6. A design method of an automobile headlamp lens is characterized by comprising the following steps:
s1, setting the integral equivalent focal length of the lens body (10) as f according to requirements, setting the two surfaces of the lens body (10) as a refractive optical surface (11) and a base surface (12), respectively, setting a diffractive optical surface (13) on the base surface (12), and setting the focal power of the refractive optical surface (11) as f
Figure FDA00024965164200000111
Satisfies the following conditions:
Figure FDA00024965164200000110
υris Abbe number, upsilon, of the refractive optical surface (11)dBeing diffractive optical surfaces (13), etcThe effective Abbe number of the active carbon,
Figure FDA00024965164200000112
is the total focal power;
s2, arranging the diffraction optical surface (13) to comprise an outer diffraction zone (131) and an inner diffraction zone (132) which are in the same circle, wherein the inner radius and the outer radius of the outer diffraction zone (131) are kr respectivelymaxAnd rmaxThe inner diffraction zone (132) has a radius krmaxCircular structure of (1), 0<k<1；
S3, setting the outer diffraction zone (131) and the inner diffraction zone (132) to have different focuses F1And F2，F1And F2The total focal length f of the outer diffractive zone (131) is shifted by + - Δ f relative to the equivalent focal length f1Satisfies the following conditions: f. of1F + Δ f, total focal length f of the inner diffractive zone (132)2Satisfies the following conditions: f. of2＝f-Δf；
S4, the focal power of the outer diffraction zone (131)
Figure FDA0002496516420000026
Satisfies the following conditions:
Figure FDA0002496516420000027
the power of the inner diffractive zone (132)
Figure FDA0002496516420000025
Satisfies the following conditions:
Figure FDA0002496516420000023
the total optical power of the outer diffraction zone (131) is
Figure FDA0002496516420000028
The total optical power of the inner diffraction zone (132) is
Figure FDA0002496516420000024
S5, the outer diffraction zone (131) satisfies the phase modulation function:
Figure FDA0002496516420000021
the inner diffractive zone (132) satisfies a phase modulation function:
Figure FDA0002496516420000022
n is the number of terms of the phase polynomial, r is the radius, Ai、BiAre all phase polynomial coefficients.
7. The design method of the automobile headlamp lens as claimed in claim 6, wherein the diffractive optical surface (13) is a micro-lens structure composed of a plurality of concentric circular rings, and the radius r and the equivalent focal length f of the first circular ring satisfy:
Figure FDA0002496516420000029
8. method for designing a lens for motor vehicle headlamps according to claim 6, characterized in that the focal power of the refractive optical surface (11)
Figure FDA00024965164200000211
Satisfies the following conditions:
Figure FDA00024965164200000210
9. the method for designing a lens for an automotive headlamp according to claim 6, wherein k is 0.5.
10. Method for designing a lens for a motor vehicle headlight as claimed in claim 6, characterized in that the total focal length f of the outer diffraction zone (131) is such that1And the total focal length f of the inner diffractive zone (132)2Satisfies the following conditions: f. of1-f2≤0.02f。
CN202010420028.6A 2020-05-18 2020-05-18 Automobile headlamp lens and design method thereof Pending CN111561682A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010420028.6A CN111561682A (en) 2020-05-18 2020-05-18 Automobile headlamp lens and design method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010420028.6A CN111561682A (en) 2020-05-18 2020-05-18 Automobile headlamp lens and design method thereof

Publications (1)

Publication Number Publication Date
CN111561682A true CN111561682A (en) 2020-08-21

Family

ID=72068229

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010420028.6A Pending CN111561682A (en) 2020-05-18 2020-05-18 Automobile headlamp lens and design method thereof

Country Status (1)

Country Link
CN (1) CN111561682A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116136294A (en) * 2023-04-17 2023-05-19 常州星宇车灯股份有限公司 Composite lens, manufacturing method thereof, car lamp and manufacturing module of composite lens
WO2024036740A1 (en) * 2022-08-15 2024-02-22 常州星宇车灯股份有限公司 Lens and vehicle lamp having same

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03122902A (en) * 1989-10-06 1991-05-24 Koito Mfg Co Ltd Heat lamp for car
CN1590835A (en) * 2003-07-23 2005-03-09 肖特股份有限公司 Lighting apparatus, lens and method of making the lens
CN102239439A (en) * 2008-12-05 2011-11-09 Hoya株式会社 Diffractive multifocal lens
US8950906B2 (en) * 2013-02-06 2015-02-10 Chen-Wei Hsu Zoom lens with multi-layers for illumination
CN107076380A (en) * 2014-09-09 2017-08-18 黑拉许克联合股份有限公司 Lighting device for vehicle
CN108626686A (en) * 2017-03-21 2018-10-09 法雷奥照明公司 Lighting module with chromatic aberration correction
CN210072174U (en) * 2019-07-23 2020-02-14 苏州大学 Single-chip achromatic mobile phone lens

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03122902A (en) * 1989-10-06 1991-05-24 Koito Mfg Co Ltd Heat lamp for car
CN1590835A (en) * 2003-07-23 2005-03-09 肖特股份有限公司 Lighting apparatus, lens and method of making the lens
CN102239439A (en) * 2008-12-05 2011-11-09 Hoya株式会社 Diffractive multifocal lens
US8950906B2 (en) * 2013-02-06 2015-02-10 Chen-Wei Hsu Zoom lens with multi-layers for illumination
CN107076380A (en) * 2014-09-09 2017-08-18 黑拉许克联合股份有限公司 Lighting device for vehicle
CN108626686A (en) * 2017-03-21 2018-10-09 法雷奥照明公司 Lighting module with chromatic aberration correction
CN210072174U (en) * 2019-07-23 2020-02-14 苏州大学 Single-chip achromatic mobile phone lens

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024036740A1 (en) * 2022-08-15 2024-02-22 常州星宇车灯股份有限公司 Lens and vehicle lamp having same
EP4350209A4 (en) * 2022-08-15 2024-04-10 Changzhou Xingyu Automotive Lighting Systems Co Ltd Lens and vehicle lamp having same
CN116136294A (en) * 2023-04-17 2023-05-19 常州星宇车灯股份有限公司 Composite lens, manufacturing method thereof, car lamp and manufacturing module of composite lens
CN116136294B (en) * 2023-04-17 2023-06-27 常州星宇车灯股份有限公司 Composite lens, manufacturing method thereof, car lamp and manufacturing module of composite lens

Similar Documents

Publication Publication Date Title
TWI603115B (en) Lens module
CN107076380B (en) Lighting device for vehicle
CN111561682A (en) Automobile headlamp lens and design method thereof
CN107894655B (en) Mobile phone lens module adopting annular aperture diffraction optics
CN106249380A (en) Optical imaging system
CN107505692B (en) Catadioptric objective lens
CN106353878A (en) Optical imaging system
TWI407176B (en) Auto-focusing lens module
CN108020908A (en) Optical imaging system
CN206757158U (en) Optical imaging system
CN107462972A (en) Optical imaging system
CN107643582A (en) Optical imaging system
CN107340589A (en) Optical imaging system
CN104216094B (en) A kind of optical lens
CN107643581A (en) Optical imaging system
CN103765278A (en) Four-lens module for image capture
CN107462982A (en) Optical imaging system
CN217718235U (en) Large-view-range and large-imaging-area optical system
Du et al. Doublet liquid variable-focus lens for spherical aberration correction
CN112987143B (en) Lens, camera module and electronic equipment
US5440422A (en) Method for manufacturing ultraviolet microscope dry objectives and microscope objectives manufactured in accordance with this method
CN109856900B (en) Optical lens group
CN105158883A (en) Projection lens and projection device
CN218938630U (en) Four-piece type digital car lamp projection lens
KR20180105707A (en) How to use prism-reinforced lens and prism-reinforced lens

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication

Application publication date: 20200821

RJ01 Rejection of invention patent application after publication