CN202868571U - High beam headlamp optical lens used for LED automotive headlamp illumination - Google Patents

Abstract

The utility model discloses a high beam headlamp optical lens used for LED automotive headlamp illumination. The high beam headlamp optical lens is made of a transparent material which is PC (polycarbonate), PMMA (polymethyl methacrylate) or optical glass, and comprises an incident plane and an emergent plane; a cavity for mounting an LED inside is formed in the center of the bottom surface of the lens; a part of the cavity wall of the cavity is a cylindrical surface; the incident plane comprises the cylindrical surface and a free curved surface at the top of the cylindrical surface; the outer side surface of the lens is the free curved surface; and the top surface of the lens is a plane which is the emergent plane. As an LED light source is high in light-emitting efficiency and the lens with the free curved surface is adopted, light rays emitted from the light source are nearly all collected and utilized, the energy utilization rate is very high, and both the light pattern and the light-emitting direction of the LED light source can be controlled at the same time; the cavity for mounting the LED is formed in the center of the bottom surface of the lens, so that the LED light source is easy to mount; the lens is small in volume, and the space is left greatly, so that a heat radiation device can be conveniently mounted; and the LED light source is turned on, and the light rays are emitted through the lens, so that the elliptic light pattern and the illuminance distribution meeting the national standard GB25991-2010 can be obtained.

Description

A kind of high beam optics lens for the LED automobile headlight illumination

Technical field

The utility model relates to LED vehicle light illumination technical field, particularly for the high beam optics lens of LED automobile headlight illumination.

Background technology

Light emitting diode (LED) is the automobile-used light source of the 4th generation after incandescent lamp, halogen tungsten lamp and high-intensity gas discharge lamp (HID).LED has the plurality of advantages such as volume is little, energy consumption is low, response is fast, the life-span is long, has complied with the trend of future automobile to future developments such as compact, energy-conservation, safety, fashion.In recent years, along with the application of LED in automobile lighting system constantly expanded, an increasing difficult problem is captured.It is still challenging that but LED is applied to car headlamp, and namely LED is different from the optical characteristics of orthodox car light source, will face complicated optical design when making LED be applied to headlamp.In order to satisfy the photometric standards of car headlamp, utilize simultaneously the little advantage of LED volume, adopt the free-form surface lens method for designing can improve the LED utilance, the establishment glare effect, and can reach the illumination requirement of instant and near light.

In the design of car headlamp, standard GB/T 25991-2010 stipulates the light distribution requirements of car headlamp, and purpose is to prevent that car headlamp from disturbing the opposite to sail vehicle and cause traffic accident.For dipped headlights, illuminated area generation one horizontal line that GB requirement 25m before car light is far away and horizontal line right side be 15 ° "cut-off"line upwards, and the brightness value size of zones of different has also been done corresponding regulation on the illuminated area.For high beam, then require the regulation zone illumination on before the car light 25m illuminated area far away up to standard.

The optical design form of LED car headlamp has refraction type, reflective and hybrid 3 kinds.Refractive LED headlamp module is made of light source, light-distribution lens usually, the light that sends from light source is through behind the light-distribution lens, form predetermined light type at receiving screen, the luminous intensity distribution of scioptics, can effectively reduce glare effect, compression optics system bulk, and optical system also has higher capacity usage ratio; The reflecting LED headlamp generally is made of light source and reflector, finishes all luminous intensity distribution tasks with single reflector, although this headlamp efficiency of light energy utilization is high, the difficult control of glare effect requires high to design, process; Hybrid LED headlamp melts refraction type, reflective advantage in one, can form good light type effect, but whole optical system is complicated, lower (the Yu Guiying of the efficiency of light energy utilization, Jin Ji, the research of the efficient paraboloid of LED car headlamp. infrared technique, 2009,31 (6): 367-370).

The utility model content

The subject matter that design faces for the LED headlamp, the utility model provides the high beam optics lens that are used for the LED automobile headlight illumination, this lens volume is little, glare effect is low, the efficiency of light energy utilization is high, fabrication and installation are convenient, and can produce the Illumination Distribution of the light distribution requirements that satisfies GB GB25991-2010.The utility model adopts following technical scheme.

A kind of high beam optics lens for the LED automobile headlight illumination are made by transparent material, transparent material is PC or PMMA or optical glass, lens comprise the plane of incidence and exit facet, the bottom center of described lens is provided with one for LED installation cavity in the inner, a part of chamber wall of cavity is cylinder, and the described plane of incidence is made of described cylinder and the free form surface that is positioned at the cylinder top; The lateral surface of lens is another free form surface, and the end face of lens is that the plane is described exit facet.

The above-mentioned high beam optics lens that are used for the LED automobile headlight illumination, its free form surface shape is determined as follows:

Set up coordinate system take led light source as the origin of coordinates, plane, place, LED bottom surface is XOY plane, cross initial point and be the z axle with the axle of the vertical XOY in plane, the light source solid angle is divided, according to dazzle lamp lamp Illumination Distribution feature on illuminated area, the uses energy law of conservation is carried out oval endless belt to the field of illumination on the illuminated area and is divided, and then uses the catadioptric law to limit last free-form surface lens by numerical computations.

The above-mentioned high beam optics lens that are used for the LED automobile headlight illumination, the free form surface that is positioned at the lens outside is determined as follows with the shape that is positioned at the free form surface of inner chamber:

Set primary condition and the light source solid angle evenly divided,

The distance of target illumination identity distance LED is d, and for high beam, it is oval setting its target illumination zone, and its major semiaxis is a, and semi-minor axis is b; The total light flux of led light source is Q, and central light strength is I ₀=Q/ π; θ is the projection of emergent ray on XOY plane and the angle of X-axis in the coordinate system,

Angle for emergent ray and Z axis positive direction; Solid angle to light source is carried out discretization,

Be divided into i part, for each

All θ is divided into j part, forms a series of angle rings region, so just obtained

And the array of θ (i, j);

Every portion

The luminous flux of the every a θ angle inner light source in the angle is:

Corresponding when determining the free form surface of lateral surface of free form surface, lens at cylinder top

Span be respectively 0～ω,

Wherein the value of ω limits the size of lens bottom bore;

Utilize law of conservation of energy that endless belt is carried out in the target illumination zone and divide,

Corresponding to the endless belt dividing mode of light source solid angle, the rectangular co-ordinate of illuminated area also is divided into the vesica piscis region accordingly, and oval major semiaxis a, semi-minor axis b are divided into i part respectively at x on the y direction, and the ellipse of formation can be expressed as:

$\left\{\begin{array}{c}x=a_i\·\cos \mathrm{\α}\\ y=b_i\·\sin \mathrm{\α}\end{array},\right.$

In the formula, a _iI part of major semiaxis a behind the expression five equilibrium, b _iI part of semi-minor axis b behind the expression five equilibrium, the span of α is 0～2 π;

For each i, all α is divided into j part, in the receiving screen rectangular coordinate system, obtain with the light source solid angle in θ (i) and

Array is a one to one _i, b _i, x (i, j) and y (i, j) array;

For the free form surface at cylinder top, on the target illumination zone, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and the gross energy of this ring belt area is:

$E_l=\mathrm{\δ}\left(k\right)\·{\∫}_{-u}^u{\∫}_0^{-v}[S(x(i+1,j),y(i+1,j))-S(x(i,j),y(i,j))]\·\mathrm{dxdy},$

In the formula, S (x (i, j), y (i, j)) the part elliptical ring region area function of expression horizontal line below, u represents oval major semiaxis, v gets the oval semi-minor axis of expression, the span of the α corresponding with it is π～2 π, δ (k) represents brightness value, according to the default illumination E of the brightness value in zone on the illuminated area of GB GB25991-2010 high beam, is used for controlling the brightness value size of appointed area on the receiving screen in conjunction with δ (k) function, in order to form predetermined Illumination Distribution, have for the zones of different on the illuminated area

$\mathrm{\δ}\left(k\right)=t\·\frac{i-k}{i}\·E,$

In the formula, k be used for to cooperate i to form the fraction ordered series of numbers that successively decreases, and makes the illumination E trend that tapers off, and its value is k=1,2, L, and i, namely k is the integer between 1～i; 0≤t≤2, t value size is strengthened appointed area on the illuminated area or is weakened;

For the free form surface of lens lateral surface, on the target illumination zone, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and the gross energy of this ring belt area is:

$E_r=\mathrm{\δ}\left(k\right)\·{\∫}_{-u}^u{\∫}_0^{-v}[S(x(i+1,j),y(i+1,j))-S(x(i,j),y(i,j))]\·\mathrm{dxdy}$

In the formula, what S (x (i, j), y (i, j)) was corresponding is the area function of part elliptical ring region, horizontal line below, and u represents oval major semiaxis, and v represents oval semi-minor axis;

The light that sends from light source all projects on the illuminated area, then between ring belt area and light source solid angle by law of conservation of energy:

E _total＝E _l+E _r，

Unite above-mentioned variously, obtain corresponding x (i, j) and y (i, j) array;

Obtain the normal vector of putting on the described curved surface by the catadioptric law, utilize this normal vector to try to achieve the section, obtain the coordinate put on the curve by the intersection point of asking section and incident ray, the vector form of catadioptric law is expressed as:

Wherein n is the index of refraction in lens, and light total reflection occurs during through the free form surface of lens lateral surfaces, and this moment, the n value was 1; Light reflects during through the free form surface at cylinder top, and the value of n is decided on lens material,

Be the incident ray unit vector,

Be the emergent ray unit vector,

Be unit normal vector;

Determine three initial points, the position of these initial points limits the size of whole lens, limits respectively two boundary curves by these three initial points, and each the upper point by boundary curve is the free form surface that initial point limits inner chamber and lens lateral surface again.

The above-mentioned high beam optics lens that are used for the LED automobile headlight illumination, the span of the parameter alpha of corresponding part ellipse is π～2 π, the corresponding light source solid angle of the free form surface at lens top

Span be 0～ω, oval major semiaxis span is 0≤a≤1.5m, the semi-minor axis span is 0≤b≤1.125m; The free form surface of lens lateral surface is the same with the restriction of the free form surface of inner chamber, and difference is the corresponding light source solid angle of the free form surface of lens lateral surface

Span be

Oval major semiaxis span is 0≤a≤4m, and the semi-minor axis span is 0≤b≤3m, and wherein the value of ω limits the size of lens bottom bore.

The above-mentioned high beam optics lens that are used for the LED automobile headlight illumination, by the θ that limits with

Get the unit vector of incident ray, obtain coordinate sequence corresponding with emergent ray on the illuminated area by law of conservation of energy, catadioptric law, thereby get the direction vector of emergent ray, the unit vector of the coordinate by initial point and the emergent ray corresponding with it, obtain the normal vector of initial point, thereby limit the section of this point, the incident ray of this section and second point intersects determines second point; Limited down a bit with the straight line at the normal vector place of descending any is crossing by more front section, draw the coordinate of having a few by computer iterations, define thus the coordinate of distance light lens free form surface; With the coordinate setting-out match of the discrete point that obtains, carry out the mirror image symmetry and namely limit final lens shape.

The above-mentioned high beam optics lens that are used for the LED automobile headlight illumination, i, the size of j value has determined the accuracy of calculating, i, larger last result is more accurate for the value of j.

After adopting technique scheme, because the led light source luminous efficiency is high and adopt free-form surface lens, the light that penetrates from light source almost can all be collected utilization, therefore capacity usage ratio is very high, simultaneously, and led light source light type, light emission direction can be controlled.Light led light source, light can obtain ellipse-shaped light type and the Illumination Distribution that satisfies standard GB/T 25991-2010 through outgoing behind the lens.The middle part, bottom surface of lens is provided with one for LED installation cavity in the inner, makes led light source be easy to install, and the volume of lens is little, reserves the installation that a large amount of spaces is conducive to heat abstractor.

The beneficial effects of the utility model and advantage: all outgoing behind free-form surface lens of the light energy that led light source sends, do not need other servicing unit to carry out luminous intensity distribution, reduced the loss of light distributing system to luminous energy, improved the efficiency of light energy utilization; Adopt free-form surface lens, can effectively increase control light trend, suppress glare effect, reduce system bulk, can reach again the light distribution requirements of GB25991-2010 simultaneously.LED and heat abstractor are easy for installation, are conducive to improve the radiating efficiency of whole light fixture.Because led light source adopts the integrated chip encapsulation technology, takies small volume, has reserved more spaces for the lamp system indoor design, makes the more flexible freedom of form-making design of whole car light, meet attractive in appearanceization and the fairshaped requirement of modern car light design.

Description of drawings

Fig. 1 is the schematic diagram of light process lens luminous intensity distribution in the embodiment.

Fig. 2 is led light source spherical coordinates schematic diagram in the embodiment.

Fig. 3 be in the embodiment on the illuminated area target area endless belt divide schematic diagram.

Fig. 4 is the schematic top plan view of distance light lens in the embodiment.

Fig. 5 is the schematic side view of distance light lens in the embodiment.

Fig. 6 is the front elevational schematic of distance light lens in the embodiment.

Fig. 7 is the three-dimensional section schematic perspective view of lens in the embodiment.

Fig. 8 is the 3 D stereo elevational schematic view of lens in the embodiment.

The specific embodiment

Below in conjunction with drawings and Examples implementation of the present utility model is made gold one and do not illustrate, but enforcement of the present utility model and protection are not limited to this.

1. set primary condition and the light source solid angle is evenly divided

At first the distance of target illumination face and LED is 25m, for high beam, the target setting field of illumination is that part is oval, its major semiaxis is 4m, semi-minor axis is 3m, and as shown in Figure 3, it is that the oval endless belt in distance light target area is divided figure, wherein 301 is the semiellipse ring belt area of horizontal line below, and a large amount of ring belt areas consists of far lighting shape zone jointly.The total light flux of led light source is 300lm, and the LED central light strength is 95.4930cd.Figure 2 shows that led light source spherical coordinates figure in the embodiment, according to the spherical coordinates diagram led light source solid angle is evenly divided.In coordinate system, θ is the projection of emergent ray 201 on XOY plane and the angle of X-axis 202, and span is 0～π,

Be the angle of emergent ray 201 with Z axis 203 positive directions, span is

Solid angle to light source is carried out discretization,

Direction

In be divided into respectively 90 parts by 1 ° of angle, for each

All the θ direction is divided into 180 parts by 1 ° of angle, forms a series of ring belt areas, so just obtained

And the array of θ (i, j), as shown in Figure 2.I, j represent the umber of five equilibrium, and the size of its value has determined the accuracy of calculating, in theory, i, larger last result is more accurate for the value of j.

Every portion

The luminous flux of the every a θ angle inner light source in the angle is:

Here corresponding when the free form surface at the top of calculating cylinder, lens lateral surface free form surface

Span be respectively 0～ω,

ω=26 °, and the value of ω affects the size of lens bottom bore.As shown in Figure 1, penetrate from the lens top after through two free form surfaces of lens from the light of led light source outgoing, wherein 101, the 102 free form surface two-dimensional representation that are respectively lens lateral surface free form surface, top.

2. utilizing law of conservation of energy that endless belt is carried out in the target illumination zone divides

As shown in Figure 3, corresponding to the endless belt dividing mode of light source solid angle, the rectangular co-ordinate of illuminated area also is divided into the vesica piscis region accordingly, and oval major semiaxis, semi-minor axis respectively at x, are divided into 90 parts on the y direction, and the ellipse of formation can be expressed as:

$\left\{\begin{array}{c}x=a_i\·\cos \mathrm{\α}\\ y=b_i\·\sin \mathrm{\α}\end{array}\right.$

In the formula, a _iI part of major semiaxis a behind the expression five equilibrium, b _iI part of semi-minor axis b behind the expression five equilibrium, the span of α is 0～2 π.

For each the group x, y, all α is divided into 180 parts, in the receiving screen rectangular coordinate system, obtain with the light source solid angle in θ (i) and Array is a one to one _i, b _i, x (i, j) and y (i, j) array.

For the free form surface at the top of cylinder, on the target illumination zone, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and as shown in Figure 3, the gross energy of this ring belt area is:

$E_l=\mathrm{\δ}\left(k\right)\·{\∫}_{-u}^u{\∫}_0^{-v}[S(x(i+1,j),y(i+1,j))-S(x(i,j),y(i,j))]\·\mathrm{dxdy}$

In the formula, the part elliptical ring region area function of S (x (i, j), y (i, j)) expression horizontal line below, u gets 1.5m and represents oval major semiaxis, and v gets 1.125m and represents oval semi-minor axis, and the span of the α corresponding with it is π～2 π.δ (k) represents brightness value, because the brightness value in zone is progressively to reduce by the centre is approximate to both sides on the illuminated area of GB GB25991-2010 high beam, therefore default illumination E, be used for controlling the brightness value size of appointed area on the receiving screen in conjunction with δ (k) function, in order to form predetermined Illumination Distribution, therefore have for the zones of different on the illuminated area

$\mathrm{\δ}\left(k\right)=t\·\frac{i-k}{i}\·E$

In the formula, k be used for to cooperate i to form the fraction ordered series of numbers that successively decreases, and makes the illumination E trend that tapers off, and its value is k=1,2, L, i; 0≤t≤2, t=1.63 here, t value size can be strengthened or weakens and need repeatedly adjust to reach optimal result in calculating appointed area on the illuminated area.

For the free form surface of lens lateral surface, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and the gross energy of this ring belt area is:

$E_r=\mathrm{\δ}\left(k\right)\·{\∫}_{-u}^u{\∫}_0^{-v}[S(x(i+1,j),y(i+1,j))-S(x(i,j),y(i,j))]\·\mathrm{dxdy}$

In the formula, S (x (i, j), y (i, j)) corresponding is the area function of part elliptical ring region, horizontal line below, and u gets 4m and represents oval major semiaxis, and v gets 3m and represents oval semi-minor axis, the α corresponding with it, δ (k) value is with above described, and the value of δ (k) needs repeatedly to adjust to reach expected results in calculating.

The light that sends from light source of supposition all projects on the illuminated area during design, then between ring belt area and light source solid angle by law of conservation of energy:

E _total＝E _l+E _r

The abscissa array in the target illumination zone that the free form surface at the top of calculating cylinder is corresponding:

$E_l=\mathrm{\δ}\left(k\right)\·{\∫}_{-u}^u{\∫}_0^{-v}[S(x(i+1,j),y(i+1,j))-S(x(i,j),y(i,j))]\·\mathrm{dxdy}$

Correspondence and each x (i, j) calculate target illumination zone y (i, j) array:

y(i，j)＝b _i·sin[arc cos(x(i，j)/a _i)]

Above various simultaneous is set up equation group, set up double cycle calculations by computer and can obtain corresponding x (i, j) and y (i, j) array.

In like manner, use said method that endless belt is carried out in the corresponding target illumination of the free form surface of lens lateral surface zone and divide and obtain corresponding coordinate array.

3. obtain the normal vector of putting on the described curved surface by the catadioptric law, utilize this normal vector to try to achieve the section, obtain the coordinate put on the curve by the intersection point of asking section and incident ray, the vector form of catadioptric law can be expressed as:

Wherein n is the index of refraction in lens, and light total reflection occurs during through the free form surface of lens lateral surfaces, and this moment, the n value was 1; Light reflects during through the free form surface at cylinder top, and its value is decided on lens material.

Be the incident ray unit vector,

Be the emergent ray unit vector,

Be unit normal vector.

In calculating, at first need to determine the initial point of three calculating, for the lens top planes, its initial point of the free form surface of the free form surface at the top of cylinder, lens lateral surface is respectively: (0,0,0.04), (0,0,0.02), (0.03,0,0.038), the size of the whole lens of determining positions of these initial points, calculate respectively two boundary curves by these three initial points, each the upper point by boundary curve is the whole free form surface that initial point calculates inner chamber and lens lateral surface again.

In the computational process, the span of the parameter alpha of corresponding part ellipse is π～2 π, the corresponding light source solid angle of the free form surface at cylinder top

Span be 0～ω, oval major semiaxis span is 0≤a≤1.5m, the semi-minor axis span is 0≤b≤1.125m; The free form surface of lens lateral surface is the same with the computational methods of aforementioned free form surface, and difference is its corresponding light source solid angle

Span be

Oval major semiaxis span is 0≤a≤4m, and the semi-minor axis span is 0≤b≤3m, ω=26 ° here, and wherein the value of ω affect the size of bore bottom the lens.

Computational process: by determined θ in the step 1 and

Can obtain the unit vector of incident ray, can obtain coordinate sequence corresponding with emergent ray on the illuminated area by law of conservation of energy, catadioptric law, thereby can get the direction vector of emergent ray, the unit vector of the coordinate by initial point and the emergent ray corresponding with it, can obtain the normal vector of initial point, thereby determine the section of this point, determine second point thereby the incident ray of this section and second point intersects.Can be drawn down a bit with the straight line at the normal vector place of descending any is crossing by more front section, can draw the coordinate of having a few by computer iterations.Determined thus the coordinate of distance light lens free form surfaces.

Example: for the free form surface at the top of cylinder, the distance of LED dazzle lamp lamp lens distance illuminated area is 25m, if starting point is (0 on the boundary line of the free form surface at the top of cylinder, 0,0.02), namely LED is 0.02m apart from the distance of lens cylinder top free form surface, lens top starting point is (0,0,0.04), namely lens height is 0.04m.Solid angle to light source is carried out discretization,

Be divided into 90 parts, for each

All θ is divided into 180 parts, obtains

And the array of θ (i, j), corresponding to the division of light source solid angle illuminated area is divided into x (i, j) and y (i, j) array.Initial angle θ is 0 °,

Value from

Arrive

Here suppose boundary curve corresponding be the horizontal center line of objective plane, y is that the value of 0, x is from x (1,1) to x (26,1).For starting point, can obtain the normal vector of starting point by law of conservation of energy, catadioptric law (N _x[1], N _y[1], N _z[1]), can obtain tangent line by normal vector and starting point coordinate is z+0.02=0, and this is (1) formula; Angle is

Linear equation be: This is (2) formula; By (1), two straight lines of (2) formula gained intersect, and obtain x (2) by step 3, z (2).By that analogy: the corresponding linear equation of k point is

Corresponding tangential equation is:

N _z[k-1](x-x(k-1))-N _x[k-1](z-z(k-1))＝0

Can obtain the k point coordinates by two straight lines are crossing, when k=26, namely obtain the coordinate array of all data points on the boundary line.

Respectively with on the boundary line each the point as starting point, for each starting point, its normal vector is known, therefore N can be passed through in the section _x(x-x ₀)+N _y(y-y ₀)+N _z(z-z ₀)=0 determines, by lower any linear equation (rectilinear direction angle θ,

Be mapped one by one)

Can determine the down coordinate of any by above-mentioned two equations.Because incident ray, the direction vector of emergent ray can in the hope of, therefore can be obtained the normal vector at each some place by law of conservation of energy, catadioptric law, set up two with this and recirculate, can obtain the coordinate array of whole free form surface.

4. the point that utilizes machine emulated software to obtain fits to curved surface

The coordinate of the discrete point that obtains is imported to mechanical modeling software successively, and the setting-out match is carried out the mirror image symmetry and namely can be obtained final high beam lens physical model.The high beam optical lens with free curved surface top view of Fig. 4 for obtaining by such scheme, wherein 402 is the lens mounting groove, and 404 is cylinder, and 403 is cylinder top free form surface, and 405 is lens outside free form surface.Fig. 5 is described lens side view, and wherein 501 is the lens top planes; Fig. 6 is described lens front view; Fig. 7 is the three-dimensional section schematic perspective view of described lens; Fig. 8 is its 3 D stereo elevational schematic view.

After adopting technique scheme, because the led light source luminous efficiency is high and adopt free-form surface lens, the light that penetrates from light source almost can all be collected utilization, therefore capacity usage ratio is very high, simultaneously, and led light source light type, light emission direction can be controlled.Light led light source, light can obtain ellipse-shaped light type and the Illumination Distribution that satisfies standard GB/T 25991-2010 through outgoing behind the lens.The middle part, bottom surface of lens is provided with one for LED installation cavity in the inner, makes led light source be easy to install, and the volume of lens is little, reserves the installation that a large amount of spaces is conducive to heat abstractor.

Claims (3)

1. high beam optics lens that are used for the LED automobile headlight illumination, it is characterized in that comprising the plane of incidence and exit facet, the bottom center of described lens is provided with one for LED installation cavity in the inner, a part of chamber wall of cavity is cylinder, and the described plane of incidence is made of described cylinder and the free form surface that is positioned at the cylinder top; The lateral surface of lens is another free form surface, and the end face of lens is that the plane is described exit facet.

2. high beam optics lens for the LED automobile headlight illumination according to claim 1 is characterized in that the shape that is positioned at the free form surface in the lens outside and is positioned at the free form surface of inner chamber limits as follows:

Limit primary condition and the light source solid angle evenly divided,

The distance of target illumination identity distance LED is d, and for high beam, it is oval limiting its target illumination zone, and its major semiaxis is a, and semi-minor axis is b; The total light flux of led light source is Q, and central light strength is I ₀=Q/ π; θ is the projection of emergent ray on XOY plane and the angle of X-axis in the coordinate system,

Angle for emergent ray and Z axis positive direction; Solid angle to light source is carried out discretization, Be divided into i part, for each

, all θ is divided into j part, form a series of angle rings region, so just obtained

And the array of θ (i, j);

Every portion The luminous flux of the every a θ angle inner light source in the angle is:

Corresponding when limiting the free form surface of lateral surface of free form surface, lens at cylinder top

Span be respectively 0～ω, , wherein the value of ω limits the size of lens bottom bore;

Utilize law of conservation of energy that endless belt is carried out in the target illumination zone and divide,

Corresponding to the endless belt dividing mode of light source solid angle, the rectangular co-ordinate of illuminated area also is divided into the vesica piscis region accordingly, and oval major semiaxis a, semi-minor axis b are divided into i part respectively at x on the y direction, and the ellipse of formation can be expressed as:

，

In the formula, a _iI part of major semiaxis a behind the expression five equilibrium, b _iI part of semi-minor axis b behind the expression five equilibrium, the span of α is 0～2 π;

For each i, all α is divided into j part, in the receiving screen rectangular coordinate system, obtain with the light source solid angle in θ (i) and

Array is a one to one _i, b _i, x (i, j) and y (i, j) array;

For the free form surface at cylinder top, on the target illumination zone, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and the gross energy of this ring belt area is:

，

In the formula, S (x (i, j), y (i, j)) the part elliptical ring region area function of expression horizontal line below, u represents oval major semiaxis, v gets the oval semi-minor axis of expression, the span of the α corresponding with it is π～2 π, δ (k) represents brightness value, according to the brightness value restriction illumination E in zone on the illuminated area of GB GB25991-2010 high beam, is used for controlling the brightness value size of appointed area on the receiving screen in conjunction with δ (k) function, in order to form the Illumination Distribution that limits, have for the zones of different on the illuminated area

，

In the formula, k be used for to cooperate i to form the fraction ordered series of numbers that successively decreases, and makes the illumination E trend that tapers off, and its value is k=1, and 2 ..., i, namely k is the integer between 1 ~ i; 0≤t≤2, t value size is strengthened appointed area on the illuminated area or is weakened;

For the free form surface of lens lateral surface, on the target illumination zone, every a θ angle is corresponding to be the ring belt area that the part ellipse surrounds, and the gross energy of this ring belt area is:

In the formula, what S (x (i, j), y (i, j)) was corresponding is the area function of part elliptical ring region, horizontal line below, and u represents oval major semiaxis, and v represents oval semi-minor axis;

The light that sends from light source all projects on the illuminated area, then between ring belt area and light source solid angle by law of conservation of energy:

E _total=E _l+E _r ，

Unite above-mentioned variously, obtain corresponding x (i, j) and y (i, j) array;

Obtain the normal vector of putting on the described curved surface by the catadioptric law, utilize this normal vector to try to achieve the section, obtain the coordinate put on the curve by the intersection point of asking section and incident ray, the vector form of catadioptric law is expressed as:

，

Wherein n is the index of refraction in lens, and light total reflection occurs during through the free form surface of lens lateral surfaces, and this moment, the n value was 1; Light reflects during through the free form surface at cylinder top, and the value of n is decided on lens material,

Be the incident ray unit vector,

Be the emergent ray unit vector,

Be unit normal vector;

Limit three initial points, the position of these initial points limits the size of whole lens, limits respectively two boundary curves by these three initial points, and each the upper point by boundary curve is the free form surface that initial point limits inner chamber and lens lateral surface again.

3. high beam optics lens for the LED automobile headlight illumination according to claim 2, the span that it is characterized in that the parameter alpha of corresponding part ellipse is π～2 π, the corresponding light source solid angle of the free form surface at lens top Span be 0～ω, oval major semiaxis span is 0≤a≤1.5m, the semi-minor axis span is 0≤b≤1.125m; The free form surface of lens lateral surface is the same with the restriction of the free form surface of inner chamber, and difference is the corresponding light source solid angle of the free form surface of lens lateral surface

Span be

, oval major semiaxis span is 0≤a≤4m, and the semi-minor axis span is 0≤b≤3m, and wherein the value of ω limits the size of lens bottom bore.

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