CN101251650B - LED three-dimensional optical system design method and optical system with given luminous intensity distribution - Google Patents

Abstract

The present invention discloses an LED three-dimensional optical system design method with given illumination distribution and an optical system, which belongs to the non-imaging optical technique of the applied optics field. A three-dimensional non-imaging optical system is formed in a region which has given illumination distribution, by using a light emitting diode as a light source. A three-dimensional lens is designed with the optical system. According to the geometrical shape of the given illumination distribution region, complying with the law of conversation of energy, the surface of the light source and the illumination plane are divided into corresponding energy regions on the long axis direction of the region in accordance with optical refraction, and energy division is carried out in the short axis direction in accordance with the principle of common function of total internal reflection and refraction. The coordinates and the normal vectors of all feature points of the optical system surface of the light source along the long axis direction and the short axis direction are calculated according to the energy corresponding relationship, so as to determine the optical system surface. The method and the system contribute to sufficiently utilizing energy and reducing engineering cost. The encapsulation of the optical system is flexible. Single chip encapsulation and multi-chip encapsulation can be adopted. The arrangement of a plurality of the optical systems is free, simple and flexible.

Description

The LED three-dimensional optical design method and the optical system of given Illumination Distribution

Technical field

The invention belongs to the nonimaging optics technology in the applied optics field, be particularly related to based on the nonimaging optics technology, (light emitting diodes is LED) as the LED three-dimensional optical design method and the optical system of the given Illumination Distribution of light source with light emitting diode.

Background technology

Compare with conventional light source, LED is all solid state light source, have that energy-saving and environmental protection, rich color, volume are little, compact conformation, response speed are fast, antidetonation, plurality of advantages such as shock-resistant, be applicable to and become the third generation lighting source that gets most of the attention by numerous areas such as comprising lighting of home, room light, auto bulb, mine illumination, field work and military operation.The led light source volume is little, and its light distribution is decay rapidly with the increase of emergence angle, can be similar to be considered as youth uncle light source.For different needs and application scenario, must adjust the light field that LED sends.Such design of Optical System belongs to the nonimaging optics scope.

The lens of traditional image optics design have rotational symmetry usually, be used for the point of object plane is looked like on the plane through being imaged onto behind the lens, what lens design was paid attention to is the preservation of picture information in imaging process, the light ray energy transfer efficiency then is placed on less important position, and therefore the common transfer efficiency of lens that designs is lower.

Nonimaging optics is to have grown up gradually abroad since the seventies in last century, specialize in a new optical branching of the power transfer problem of light, compare with traditional image optics, pay close attention to the transfer efficiency of energy more and in space and azimuthal distribution.The collection that nonimaging optics is mainly studied sun power at first utilizes problem, light coupled problem just, how the incident ray of a big input aperture is collected, be transmitted in a little output aperture fully, thereby in research process, improving aspect energy density utilizes, produce a cover gradually and be used to control the theory that light ray energy is transmitted, as " marginal ray theory " (Ries, H and Rabl, A " Edge-ray principle of nonimaging optics; " J.Opt.Soc.Am.43 712-715), (the H.Ries that " cuts out theory ", J.A.Muschaweck, " Tailoring freeform optical lensesfor illuminations; " Novel Optical Systems Design and Optimization IV, Proc.SPIE, vol 4442, pp.43-50, (2001)) (Andreas Timinger a, JuliusGeneral Illumination; ", Proc.SPIE, vol 5186, pp.128-132, and " symmetrical analysis theory " (Ries, H Shatz, N (2003)), Bortz, J and Spirkl, W " Performancelimitations of rotationally symmetric nonimaging devices " J.Opt.Soc.Am.A vol 14,10,2855-2862,1997).Another direction of nonimaging optics development is illuminator of design, can use a given light source to form given Illumination Distribution, just given Illumination Distribution problem on a target screen.

The problem that nonimaging optics faces in the space of different dimensions has different difficulty.The nonimaging optics of two-dimensional space is mainly studied to be had necessarily symmetricly, as rotates the symmetry and the optical system of translation symmetry.Though symmetry has been carried out certain simplification to the nonimaging optics problem, made things convenient for and found the solution, but symmetry itself will restrict the further raising of transfer efficiency, therefore for the basic energy transmission efficiency problem that solves, the difficulty that present nonimaging optics mainly faces is how will find the solution the space to be extended to field of three dimension, and design does not have symmetric optical system.This has been proposed a lot of advanced persons' theory and algorithm abroad:

Aspect the light coupled problem, the method that can design the three dimensions optical system at present theoretically has Bo Yinting to draw together arrow (J.C.Minano " design of three-dimensional nonimagingconcentrator with inhomogeneous media " J.opt.Soc.Am A (3) pp.1345-1353,1986), streamline method (R.Winston, W.T.Welford " Geometrical vectorflux and some new nonimaging concentrators ", J.opt.Soc.Am69 (4), pp.532-536,1979) and Lorentz method of geometry (Guti é rrez, M., Minano, J.C., Vega, C.and Ben í tez, P. " Application of Lorentz Geometryto Nonimaging optics:New 3D ideal concentrators ", J.opt.Soc.Am13, pp.532-540,1996), these methods have proved that theoretically free three-dimensional optical system can the realization theory transfer efficiency, yet because the method for design is very complicated, and the dielectric material that needs graded index can not be used for designing practical optical system.(Simultaneous multiplesurface SMS) is the method that is used for designing the practical optics system (P.Ben í tez, the J.C. of up-to-date proposition to multilist face method for designing simultaneously

Et al, " Simultaneous multiple surface optical design method inthree dimensions ", Opt.Eng, 43 (7) 1489-1502, (2004)), owing to adopted the distinctive design theory of nonimaging optics in the design--" marginal ray " theory, realized having the three-dimensional surface optical system of uniform dielectric material, yet the SMS method for designing wants to be generalized to given Illumination Distribution problem, still require that given Illumination Distribution is transformed into optical wave-front earlier and adopt method to design then, therefore must find the solution several second nonlinears and cover special ampere equations with the light coupling;

Aspect given illumination problem, mainly contain two research directions at present: utilize the variational integral optimization method, the geometric approximation method is found the solution method (the L.Caffarelli and V.Oliker that second order nonlinear is covered special ampere equation, " Weak solutions of one inverse problem in geometric optics " Preprint, 1994.) (S.Kochengin and V.Oliker, " Determination ofreflector surfaces from near-field scattering data II.Numericalsolution; " Numerishe Mathematik 79 (4), pp.553-568,1998.) (L.Caffarelli, S.Kochengin, and V.Oliker, " On the numerical solution ofthe problem of reflector design with given far-field scattering data; " Contemporary Mathematics 226, pp.13-32,1999.) and the cut-out method of free three-dimensional surface.Adopt geometric approximation and this method of variational integral mainly to be used in the given Illumination Distribution problem of having only a reflecting surface of finding the solution.Utilize the method for geometric approximation the problem of finding the solution a reflective surface can be transformed into the problem of finding the solution a series of reflective surface, ask the method for the limit finally to obtain a convergent reflective surface to these a series of reflective surfaces then, yet can not guarantee the smooth degree of reflective surface, be called weak approximate solution; Adopt the method for variational integral the problem of finding the solution reflective surface can be changed into the problem that variation is asked extreme value, therefore be convenient to adopt the method for optimization to find the solution, more than all exist convergent to separate on two kinds of theoretical methods, but because solution procedure complexity, increase along with solving precision, calculated amount rapidly increases, and efficiency of algorithm is low; The method that free three-dimensional surface is cut out makes up the mathematical model of refractive surface on principle, target is to adopt refractive surface to realize given Illumination Distribution, final mathematical model still is summed up as finds the solution the special ampere of SEVERAL NONLINEAR second order illiteracy equation, and because in solution procedure, adopt the continuous method of curved surface Gaussian curvature to guarantee the local slickness of curved surface, can in small angle range, obtain more satisfactory Illumination Distribution, along with the increase of angle, can not guarantee the existence of refractive surface.

In the design of Optical System that given Illumination Distribution, illumination flat shape require, can adopt refraction or total reflection to change the light source light field distribution usually, realize designing requirement.Only adopting in the design proposal of refraction, it is limited that the emergence angle of source light changes degree, when realizing the optical system of less shooting angle, the wide-angle source light can not guarantee the existence of refractive surface, also promptly in the design that requires at less beam angle, can't consider the wide-angle source light, thereby reduce the light source efficiency of light energy utilization, as in the street lamp design, road is had a lot of social connections and has been limited the size of horizontal beam angle, and the refraction scheme is difficult for making full use of energy of light source on breadth wise dimension.And the design proposal of use total internal reflection, easily in low-angle, realize uniform illumination but can't when big shooting angle, guarantee the homogeneity of illumination, this just forces the deviser to increase the distance of system and target area, to reduce beam angle, as when street lamp designs, hoisting depth to be reducing the beam projecting angle, thereby in a disguised form improved cost; In addition, compare with refraction, its angular error of the source light after the total internal reflection can double, and this has also improved making the requirement of precision.

Design proposal among the present invention, both advantages have been taken all factors into consideration, at Illumination Distribution shape with certain breadth length ratio, adopt the refraction scheme at long axis direction, and adopt the scheme of total internal reflection in conjunction with refraction at short-axis direction, both overcome the shortcoming that refraction can not make full use of energy of light source, overcome the limitation that total internal reflection brings simultaneously, obtained good notional result and actual performance.

Summary of the invention

The LED three-dimensional optical design method and the optical system that the purpose of this invention is to provide a kind of given Illumination Distribution.It is characterized in that, with light emitting diode as light source, decide Illumination Distribution zone and form three-dimensional non-imaging optical system given, carry out the three-dimensional lens design with this optical system, the basic procedure of its three-dimensional lens design: at the geometric configuration in given Illumination Distribution zone, follow law of conservation of energy, according to light refraction the light source surface is divided into corresponding energy area with the illumination plane at regional long axis direction, and carries out energy binned according to total internal reflection and the coefficient principle of refraction at short-axis direction; Determine the initial value of any one initial point of given illumination plane and any one light-source angle, calculate the ranges of incidence angles of the energy area that the angular range of source light emergence angle and light source projects divide to the illumination plane of correspondence according to the energy corresponding relation, iterate all characteristic point coordinates and the normal vector that the method for finding the solution is obtained optical system surface according to angle corresponding relation and utilization again, thereby determine the surface of optical lens.

Described given illumination plane coordinate system and light source coordinate are rectangular coordinate system or cylindrical coordinate or spherical coordinate system or other preferred coordinate system.

The initial value of any one initial point of described given illumination plane and any one light-source angle be at illumination plane establishment long axis direction X and short-axis direction Y, set up coordinate system (X, Y), a given illumination plane initial point (x ₀, y ₀); The light source rising angle set up coordinate system (U, V), the initial value (u of a given light source rising angle ₀, v ₀); Given major axis zone of dispersion number N_L, minor axis zone of dispersion number N_W; Given light source height H; Given optical system height h; Given optical system material refractive index n and air refraction n ₀Given energy of light source and angle concern E (u, v).

The surface of described definite optical lens is according to above-mentioned given starting condition, adopts the method for variational integral to find the solution the surface curve of optical lens, be calculated as follows,

1) corresponding relation and the curve of calculating long axis direction: the illumination plane is divided into N_L zone by long axis direction, calculates each region energy weight E_L (i), the major axis coordinate x of i=0～N_L, zone boundary correspondence _i, i=0～N_L

2) according to energy weight and given angle initial value calculating energy corresponding relation, determine that the angular divisions of long axis direction concerns u _i, i=0～N_L satisfies

$\underset{u_{i-1}}{\overset{u_i}{\∫}}\underset{0}{\overset{\mathrm{\π}}{\∫}}E(u,v)\mathrm{dvdu}=E\_L\left(i\right),i=1~N\_L---\left(2.1\right)$

3) the angle of incidence of light degree uX of calculating long axis direction zoning, illumination plane correspondence _i, i=0～N_L is according to itself and source light angle u _i, the corresponding relation of i=0～N_L calculates long axis direction refractive surface normal vector ${\stackrel{\→}{n}}_X(u_i,v_0),i=0~N\_L;$ Adopt iteration technique to calculate the characteristic point coordinates (u of refractive surface one by one again _i, v ₀, R _i), i=0～N_L obtains long axis direction refraction curve.

4) corresponding relation and the curve of calculating short-axis direction are on the basis that long axis direction is divided, to different major axis incident angle uX _i, i=0～N_L, with the illumination plane according to short-axis direction be divided into respectively N_W the zone, calculate each region energy weight E_W (i, j), i=1～N_L, j=1～N_W, the minor axis coordinate y of zone boundary correspondence (i, j), i=0～N_L, j=0～N_W;

, and satisfy after superrefraction and the source light of outgoing through total internal reflection

$\underset{u_{i-1}}{\overset{u_i}{\∫}}\underset{v_{j-1}}{\overset{v_j}{\∫}}E(u,v)\mathrm{dvdu}+\underset{u_{i-1}}{\overset{u_i}{\∫}}\underset{v_{j-1}^{\′}}{\overset{v_j^{\′}}{\∫}}E(u,v)\mathrm{dvdu}=E\_W(i,j),i=1~N\_L,j=1~N\_W---(2.2)$

5) the angle of incidence of light degree vY of calculating short-axis direction zoning, illumination plane correspondence _{I, j}, i=0～N_L, j=0～N_W is then according to angle of incidence of light degree uX _i, i=0～N_L and vY _{I, j}, i=0～N_L, j=0～N_W and source light angle u _i, i=0～N_L and v _{I, j}, i=0～N_L, the corresponding relation of j=0～N_W, calculated direction optical system short-axis direction refractive surface normal vector respectively ${\stackrel{\→}{n}}_Y(u_i,v_j),i=0~N\_L,j=0~N\_W;$ The total internal reflection surface normal vector ${\stackrel{\→}{n}}_Y(u_i,v_j),i=0~N\_L,j=0~N\_W,$ Adopt iteration technique to calculate the characteristic point coordinates (u of refractive surface one by one again _i, v _j, R _{I, j}), (u _i, v _j', R _{I, j}'), i=0～N_L, j=0～N_W obtains the optical system surface curve.

Described light source has rectangle, ellipse, dolioform or the spindle and their stack of certain breadth length ratio on given illumination plane of deciding the Illumination Distribution zone.

Described given energy distribution of deciding the Illumination Distribution zone is that even distribution, Gaussian or Lorentz lorentz's type distribute.

The LED three-dimensional optical system of described given Illumination Distribution, form the LED three-dimensional optical system of pressing given Illumination Distribution according to the optical system surface curve that aforementioned calculation obtains, wherein the side is the total internal reflection curved surface, end face is the refraction curved surface, curved surface is straight line, circular arc line, parabolical, hyperbolic curve along the short-axis direction cross section, or the surface formation symmetrical structure of their combinations, and press light-source angle and launch; Curved surface is fan-shaped, shell-like or saddle-shaped continuous curve surface along long axis direction; Single or multiple LED are encapsulated in the optical system simultaneously, and a plurality of light source units are combined to form even or periodically variable Illumination Distribution on a large scale, and keep given Illumination Distribution shape invariance.

The described led light source that is encapsulated in the optical system is to be the led light source of single wavelength, the led light source of composite wavelength.

The led light source of described composite wavelength is the LED of a plurality of different wave length LED or single multi-wavelength LED or a plurality of multi-wavelengths.

Described optical system uses transparent material to adopt any means of mold, engraving, cutting, polishing or die casting to carry out processing and fabricating.

The employing of described optical system is bonding, ultra-sonic welded, fixing or any one mode of interlock are fixed on the encapsulation base plate of LED.

The described led light source that is encapsulated in the optical system, a plurality of light source units have certain spacing at the optical system long axis direction, and the spacing minimum value is by the height and the rising angle decision of optical system; And can closely arrange or keep a determining deviation at short-axis direction; Spacing between the optical system can equate also can be unequal, and arrangement mode adopts array or adopts non-array.

The refractive index of described transparent material is between 1.3～3.5;

Described optical system is to spend or spend less than 180 greater than spending, equal 180 greater than 180 to the subtended angle of light source.

The invention has the beneficial effects as follows and overcome the limitation that adopts refraction in the conventional road lamp design separately or adopt total internal reflection theoretically, and kept refraction and had the advantage that beam angle, total internal reflection greatly realize less beam angle easily, according to the application demand on the different directions, design is divided at long axis direction with at short-axis direction two parts content, design respectively, in the simplified design difficulty, realize the efficient utilization factor of light source luminous energy, and had outstanding actual performance and economic worth.In design, the present invention has brought into play the advantage of light emitting diode aspect energy-conservation, is controlled in the specific scope by a kind of actual mechanism by the light that light emitting diode is sent, and realizes specific Illumination Distribution in the given area, far field.Simultaneously, having the field of illumination of specific illumination requirement can infinite expanding.The purpose of this invention provide a kind of simple and convenient, have a LED design of Optical System scheme of good Illumination Distribution and energy control.

The three-dimensional LED optical system of the present invention's design makes full use of the energy of light source, thereby saves the energy, has broad application prospects.

Description of drawings

Fig. 1 has specific breadth length ratio field of illumination synoptic diagram.

Fig. 2 divides synoptic diagram to the long axis direction of field of illumination energy and energy of light source.

Fig. 3 divides synoptic diagram once more to the short-axis direction energy of field of illumination energy and energy of light source.

Fig. 4 is that long axis direction is drawn the source light original angle and angle synoptic diagram behind lensing after the energy binned.

Fig. 5 is that energy is divided back short-axis direction source light original angle and the angle synoptic diagram behind lensing once more.

Fig. 6 is lens long axis direction surface curve and data point synoptic diagram thereof.

Fig. 7 is a series of short-axis direction surface curve of lens and data point synoptic diagram thereof.

Fig. 8 generates the lens curved surface synoptic diagram according to data point.

Fig. 9 has the encapsulation synoptic diagram that fan-shaped outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains.

Figure 10 has the encapsulation synoptic diagram that shell-like outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains.

Figure 11 has the encapsulation synoptic diagram that saddle-shape outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains.

Figure 12 is an encapsulation synoptic diagram according to the formation cruciform illumination zone optical lens of algorithm acquisition.

Figure 13 is that synoptic diagram is arranged according to the specific configuration mode by a plurality of light source units.

Figure 14 utilizes two formation rectangle illumination zone optical lenses that obtain according to algorithm to form an encapsulation synoptic diagram in cross illumination zone jointly.

Figure 15 is the process flow diagram of the design's method.

Embodiment

LED is as novel lighting source, and its volume is little, can be similar in the package lens design and regard pointolite as.The lens design method that proposes is based on energy conservation theory, the energy on illumination plane and the energy of pointolite is divided according to planimetric coordinates and orientation angle respectively in the present invention, and makes energy corresponding one by one.In this partition process, the algorithm among the present invention is at first separated according to major axis the energy on illumination plane with minor axis, simultaneously with energy of light source according to the counterparty to separating, calculate two kinds of energy corresponding relations on axially respectively; Separately discrete point and corresponding one by one will be set up subsequently in illumination planimetric coordinates and the light-source angle direction coordinate; Then according to the corresponding relation of this coordinate points, long axis direction according to refraction effect, at short-axis direction according to total internal reflection with reflect coefficient effect and iterate the coordinate that calculates the lens surface discrete data point successively, thereby determine the shape of lens surface.

It is emphasized that, in the algorithm that the present invention proposes, can determine long axis direction and short-axis direction in the illumination zone, perhaps can be divided into some stacks with specific breadth length ratio zone, then long axis direction, short-axis direction are considered different algorithms respectively: when long axis direction iterates calculating lens surface data point, only consider refraction effect; When short-axis direction iterated calculating lens surface data point, iterating result of calculation with major axis was initial point, the acting in conjunction of considering total internal reflection and refraction, finally obtains whole lens surface data point.

Utilize energy unit to divide the method for carrying out lens design, at first be used in the designing requirement that forms given light distribution and (see W.A.Parkyn, " adopting the method design illuminating lens of exterior differentiation geometry ", Proc.SPIE, vol 3482, pp.191-193 (1998) .).In the method that the present invention proposes, the energy unit division methods at first is separated into major axis and the minor axis both direction is considered respectively, and further promoting becomes point-to-point or regional mapping relations to the zone, and this energy distribution can be used for forming given uniform illumination and distribute or non-homogeneous Illumination Distribution.Its division methods is applicable to the relative and smaller situation of optical system of dimension of light source, and certain application value is also arranged in expansion light source.Since in the process of energy binned, two separated processing of variable of illumination planimetric coordinates and light-source angle coordinate, and therefore this method also can be thought the method that variable separates.

Suppose to send from light source, the light in our limit of consideration all incides on the plane of given illumination, can obtain according to law of conservation of energy:

${\∫\∫}_{\mathrm{\Ω}}I\left(\stackrel{\→}{i}\right)\mathrm{d\Ω}={\∫\∫}_{D}L\left(\stackrel{\→}{p}\right)\mathrm{ds}---\left(1\right)$

In formula (1)

The direction of expression light,

Be the light distribution on the pointolite angle direction.

Some position on the expression objective plane,

Illumination Distribution for given illumination plane.The solid angle scope that the Ω representative emits beam from light source, the range of exposures of D representative on objective plane.

A mapping on reflecting surface in the optical system or refractive surface are actually and realize from the light source to the irradiated plane $Y:\stackrel{\→}{i}\→\stackrel{\→}{p},$ Its implication makes conversion exactly $Y\left(\stackrel{\→}{i}\right)=\stackrel{\→}{p}$ Set up, and

Wherein The size of the Jacobian that the mapping Y of expression definition has.

When the method for utilizing energy binned is found the solution a mapping from the light source to the objective plane, according to energy conservation formula (1), to the light source light direction adopt (u, v) coordinate system is described, to the position on illumination plane adopt (x, y) coordinate system is described and can obtains:

I(u，v)|J(u，v)|dudv＝L(x，y)|J(x，y)|dxdy (3)

Wherein | and J (u, v) | (u, v) coordinate system need be scaled dudv the Jacobian of unit area in order to adopt

| J (x, y) | (x, y) coordinate system need be scaled dxdy the Jacobian of unit area in order to adopt

With the energy of light source along the u line (along the v line also can) be divided into a series of energy area simultaneously with corresponding objective plane energy along the x line (along the y line also can) be divided into a series of energy areas, can obtain:

(∫I(u，v)|J(u，v)|dv)du＝(∫L(x，y)|J(x，y)|dy)dx (4)

Equation (4) is an One first-order ordinary differential equation f (u) du=g (x) dx, just can adopt the method for numerical evaluation to iterate after the given starting condition and find the solution.Find the solution out the vertical corresponding relation U=h (X) that obtains energy, identical method can draw horizontal corresponding relation V=m (Y).

To can obtain in equation (4) the substitution equation (3):

$I(u,v)\left|J(u,v)\right|\mathrm{du}=L(x,y)\left|J(x,y)\right|\frac{\∫I(u,v)\left|J(u,v)\right|\mathrm{du}}{\∫L(x,y)\left|J(x,y)\right|\mathrm{dx}}\mathrm{dx}---\left(5\right)$

The mapping relations of the point-to-point that is actually equation (a 3) requirement of satisfying to have Jacobian that from equation (4) and (5), obtains.In the definition of this mapping, key is that (u is v) with the variable (x that represents the illumination position to the variable that is used to represent radiation direction, y) divide other correspondence, in division, can adopt different orthogonal curvilinears to cut apart, as polar curve or rectangular coordinate curve.After the division by above-mentioned energy, just set up grid lattice point one-to-one relationship from light source to the illumination plane.Light from light source sends through behind the optical surface, just is projected onto corresponding correspondence position on the illumination plane.

It is pointed out that when long axis direction is divided, owing to only consider refraction effect, so the mapping relations that obtained $Y:\stackrel{\→}{i}\→\stackrel{\→}{p}$ Normally can lead continuously, thereby its curve that iterates is normally continuous; And at short-axis direction, owing to consider the effect of refraction and total internal reflection simultaneously, its mapping relations $Y:\stackrel{\→}{i}\→\stackrel{\→}{p}$ Usually discontinuous leading exists flex point or limit, needs to divide total internal reflection angle light and refraction angle light respectively according to energy corresponding relation and conservation of energy principle, and it is satisfied

$\underset{u_{i-1}}{\overset{u_i}{\∫}}\underset{v_{j-1}}{\overset{v_j}{\∫}}E(u,v)\mathrm{dvdu}+\underset{u_{i-1}}{\overset{u_i}{\∫}}\underset{v_{j-1}^{\′}}{\overset{v_j^{\′}}{\∫}}E(u,v)\mathrm{dvdu}=E\_W(i,j),i=1~N\_L,j=1~N\_W---\left(6\right)$

V in the formula _j, v _j' be respectively only by the light angle of refraction outgoing with by total internal reflection and the coefficient light angle of refraction; E (u, v), E (u, v ') is respectively the energy density of angle separately; (i is j) for dividing the corresponding energy weight in back for E_W.This calculating is complicated more than the calculating on the long axis direction.

Based on above principle, in the method for the present invention design, at first utilize the pass of energy conservation to tie up to pointolite and determine a vertical curve that constitutes by some discrete points corresponding to illumination plane long axis direction, form the corresponding relation of energy at long axis direction; Be starting point with the discrete point on this curve then, according to the division result of short-axis direction, some the horizontal curves that formation is made of some discrete points, form the thinner horizontal corresponding relation of energy, thereby the corresponding energy corresponding relation that the discrete point on light source light direction and illumination plane is formed, and obtain all discrete points of lens surface coordinate, determine the lens surface shape.Concrete steps are seen summary of the invention.

In above-mentioned steps, (x, y) (u v) preferably adopts same initial point, so that subsequent calculations to the illumination plane coordinate system with the light source direction coordinate system.As the coordinate of pointolite light direction, coordinate system (u v) can be spherical coordinates or polar coordinates etc. so that variables separation, and the illumination plane coordinate system (x y) generally can adopt rectangular coordinate.In the illumination zones that can be divided into some zones stacks with certain breadth length ratio, this stack can be not overlapping in the space, can overlap in the space and independent at energy space yet.

The selection of initial point is a very important design parameter, the position of having only rational selection initial point, as the boundary value of light source parameters and the boundary value of illumination plane parameter or the central value of light source parameters and the central value of illumination plane parameter are carried out correspondence, just may obtain easy, rational corresponding relation.In step, during according to the energy binned corresponding relation, it is accurate more to divide the close more approximate solution that obtains; This division can be carried out according to homenergic, also can according to as (x, y) the coordinate spacing that waits of coordinate system is carried out, also can be according to (u, v) the equal angles spacing of coordinate system is carried out.Reasonably set division points number, dividing mode and division principle, help obtaining simple, fast computing method.For initial light (u ₀, v ₀) and initial point (x ₀, y ₀) selection, can select the point of edge or center so that calculate.

In iterating of lens surface data point found the solution,, select (u for the ease of calculating ₀, v ₀) proper as initial light.Behind the curve of obtaining a long axis direction, point on the curve is a starting point successively, when finding the solution a series of horizontal curve, can select to find the solution more arbitrarily, as long as all horizontal curves that are starting point with these points are found the solution out, not necessarily find the solution in order.

According to the algorithm design lens among the present invention the time, can mediate to the energy distribution on illumination plane according to result of calculation, with the correction deviation, or get the result who adheres to specification more.

In some designs of using this method, the light source of some employing need once encapsulate, be that the light that light source sends need pass some given surfaces, as led light source is actual use in for the light extraction efficiency that improves LED and easy to use, need in advance led chip once to be encapsulated, and employing is as the packaged type of globe lens; Or in order to cooperate the once encapsulation of light source, on the substrate of the lower surface of lens, there is groove of definite shape etc.Therefore need to consider some given surfaces of existence in the design, as sphere or plane.In these influence factor unifications can being distributed to light source intensity this moment, be about to the light distribution situation from only considering the light distribution situation after the LED light distribution changes once encapsulation factors such as considering to comprise lens, groove into.The ray tracing that can earlier light source be sent is crossed these given surfaces.For known optical surface, it is n that light has refractive index from a side of this optical surface ₁Medium in incide opposite side to have refractive index be n ₂Medium in, can be easy to obtain the position of intersecting point P on light and known optical surface, thereby obtain normal direction in P point position, can utilize refraction law to obtain emergent ray direction after light leaves given optical surface then.The method on the given surface of ray tracing is ripe prior art, can be with reference to (R.Courant, L.Bers, J.J.Stoker " Modern Geometrical Optics (Modern Geometry optics) ", IntersciencePublishers, Inc, New York) document.

Division methods at the energy of given optical surface is the same with there not being the situation of given optical surface because energy binned definite be the corresponding relation on light source and illumination plane, and the effect of optical system is exactly to realize this corresponding relation.

According to above-mentioned method for designing, obtained the discrete data point of lens surface after, can be earlier the data point of all short-axis directions be linked to be line, constitute a series of curve, then these curves are connected into curved surface.This connection can be obtained these points, horizontal curve smooth, that have given tangential direction and corresponding little patch according to point coordinate on the curve and tangential direction according to NURBS (non-uniform rational b spline curve) theory.At last these little patchs are coupled together, just constituted the full surface of lens.

Describe below in conjunction with accompanying drawing:

Fig. 1 provided the present invention at the illumination area schematic: the illumination zone can be that the geometric figure with specific breadth length ratio includes but not limited to that (a) rectangle, (b) are oval, (c) is dolioform; Also can be geometric stack with specific breadth length ratio, and this stack can have in volume coordinate overlapping, " ten " word illumination zone as shown in (d).

Fig. 2 (a) expression is carried out energy binned to the illumination plane according to long axis direction: the border in 21 expression energy binned zones, and the zone that 22 expressions are divided, these regional energy can equate, also can be unequal; (b) expression is divided according to the principle of energy correspondence accordingly to light source 25, and the 23rd, the border of light-source angle direction zoning, the 24th, the zone after light-source angle is divided, these zones are corresponding one by one with zone 22 energy that the illumination plane is divided.

Fig. 3 (a) is illustrated on the basis that major axis divides, and further energy binned is carried out according to short-axis direction in the illumination plane: the border in 31 expression energy binned zones, and the zone after 32 expressions are further divided, these regional energy can equate, also can be unequal; (b) expression is carried out division on the corresponding short-axis direction to light source 25 according to the principle of energy correspondence, and the 33rd, the border of light-source angle direction zoning, the 34th, the zone after light-source angle is divided, these zones are corresponding one by one with zone 32 energy of illumination plane division.

Only consider the light source light line angle of refraction effect and the corresponding relation of illumination plane incident angle when Fig. 4 is illustrated in the long axis direction calculated curve: 21 expression major axis are divided the border of time domain, the 41st, its corresponding illumination plane incident angle, 42 is light angles that 41 light sources 25 before refraction send, and this division light ray energy that satisfies the corresponding region equals the energy of illumination plane respective regions; The 43rd, realize the refraction curved surface curve of this light corresponding relation, can be but be not limited to fan-shaped, shell, shape of a saddle outline line.

When Fig. 5 is illustrated in the short-axis direction calculated curve and considers total internal reflection and refraction effect simultaneously, the corresponding relation of light source light line angle and illumination plane incident angle: the 31st, the border of short-axis direction zoning, illumination plane, the light 51 that sends from light source 25, a part directly projects the illumination plane through unirefringence 52, another part 52 projects the illumination plane through total internal reflection and refraction, and through after the division of this light angle, the light ray energy that projects the illumination plane distributes and satisfies the energy distribution requirement of illumination plane; The 54th, the total internal reflection curve of this corresponding relation of realization, the refraction curve 55 of end face can be but be not limited to straight line, circular arc line, parabolical, hyperbolic curve and combination thereof.

Fig. 6 is according to long axis direction energy corresponding relation, iterates the major axis curve that calculate to obtain according to refraction effect and starting point, starting point can be on the curve in the discrete point 61 more arbitrarily; Iterate when calculating, data point 62 is as the initial value that iterates of adjacent new data point 63, and both satisfy corresponding light source light line angle vector respectively with the vector 621 and 631 that light source 60 constitutes, and both lines 64 are perpendicular to the normal vector 65 of the refractive surface of 62 correspondences.

Fig. 7 is on the basis that major axis calculates, and iterates data point 71 and the curve 72 that calculates a series of short-axis directions that obtain according to energy corresponding relation and total internal reflection, refraction effect.The account form that iterates long axis direction among account form and Fig. 6 of every horizontal curve is similar.Different is when calculating horizontal direction curve data point normal, must distinguish total internal reflection and refraction, thereby there is obvious flex point in the curve of its formation.

Fig. 8 is the synoptic diagram that generates lens surface according to the lens surface data point that obtains, and wherein side 81 is the total internal reflection curved surface, and end face 82 is the refraction curved surface.Curved surface 81 is the plane of symmetry along the short-axis direction cross section, and presses light-source angle and launch, and only considers its total internal reflection effect to source light during calculating; Curved surface 82 is a continuous curve surface along long axis direction, can be shapes such as fan-shaped, the shell-like or the shape of a saddle, along short-axis direction then can be but be not limited to the surface of straight line, circular arc line, parabolical, hyperbolic curve and combination thereof, only consider the refraction action of 82 pairs of source lights of curved surface during calculating.

Fig. 9 (a) has the encapsulation 3 D stereo synoptic diagram that fan-shaped outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains, and Fig. 9 (b) is local 90 a enlarged diagram shown in Fig. 9 (a).Lens 91 can adopt the mode that includes but not limited to mold, engraving, cutting, polishing or die casting to make, and directly are bonded on the base plate 92; Light source led 94 places the shrinkage pool 93 at base plate 92 centers, and is positioned at lens 91 bottom centre; Lens form 180 degree subtended angles to light source 94, and top 95 is an arcuate surface, and what it formed at last is the uniform illumination zone with swelling-waist shape.

Figure 10 (a) has the encapsulation 3 D stereo synoptic diagram that shell-like outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains, and Figure 10 (b) is local 100 a enlarged diagram shown in Figure 10 (a).Lens 101 comprise that its bottom has as the annex 105 that connects, and can adopt the mode that includes but not limited to mold, engraving, cutting, polishing or die casting to make, the plane that its short-axis direction upper surface 107 constitutes for straight line; Lens 101 are fixed on the base plate 102 by parts 106; Light source is the LED103 with a package lens 104, is positioned at the center of design lens 101 bottom couplings 105; 101 pairs of light source angulations of encapsulation rear lens are less than 180 degree; Form the oval illumination zone that strong edge, illumination center is weak, illumination is successively decreased gradually at last.

Figure 11 (a) has the encapsulation 3 D stereo synoptic diagram that saddle-shape outward appearance, short-axis direction have the symmetrical appearance optical lens according to the long axis direction that algorithm obtains, and Figure 11 (b) is local 110 a enlarged diagram shown in Figure 11 (a).Light source is four and is the LED 113 that matrix pattern is arranged, and be positioned on the protruding attached frame 114 at base plate 112 centers, and light source 113 and additional 114 is immersed in the lens 111; Lens 111 can adopt the mode that includes but not limited to mold, engraving, cutting, polishing or die casting to make, and its top center depression is as saddle, and short-axis direction upper surface 116 is the plane of straight line formation; Lens 111 are engaged on the base plate by the interlock annex 115 on the base plate 112; 111 pairs of light source 113 angulations of lens are greater than 180 degree; Form at last and have the rectangular region of uniform illumination.

Figure 12 (a) is an encapsulation 3 D stereo synoptic diagram according to the single optical lens in formation cruciform illumination zone of algorithm acquisition, and Figure 12 (b) is the enlarged diagram of part 120 shown in Figure 12 (a).Lens 121 can be regarded two lens with lens 111 architectural features that obtain rectangle illumination shape as previously mentioned as, by cross stack gained; The light source that encapsulation is adopted is four LED123 that are cross spread; Lens are made and also can be adopted the mode that includes but not limited to mold, engraving, cutting, polishing or die casting to make, can be bonding by including but not limited to, ultra-sonic welded, the any-mode that adds heat fixation or interlock be fixed on the base plate 122; What form at last is the uniform illumination zone with cross shape.

Figure 13 is the schematic top plan view of the concrete in actual use arrangement mode of light source unit 131 in a plurality of formation rectangle illumination as shown in Figure 11 zone, include but not limited to following arrangement mode: (a) be according to the rectangular array synoptic diagram of arranging, wherein long axis direction is kept at a distance and is avoided covering mutually between lens rising angle, its spacing is by the beam angle of lens and size decision, and keeps a determining deviation at short-axis direction; Major axis keeps spacing and the array synoptic diagram of minor axis solid matter when (b) then having provided the rectangle permutation and arrange; (c) non-rectangular array, the staggered synoptic diagram of evenly arranging have been provided; (d) provided the non-homogeneous synoptic diagram of arranging.The illumination region shape that each light source unit 131 forms among the figure is identical, light distribution is also identical, and the number of light source unit depends on the illumination total value and the formed brightness value of each light source unit that will reach.

Figure 14 adopts a plurality of lens 141 to form the lens arrangement mode synoptic diagram in cross uniform illumination zone: (a) be the implementation schematic top plan view that adopts two lens, among the figure between two lens angle be 90 degree, form a rectangle illumination zone respectively, two zone stack backs form criss-cross uniform illumination zones, when arranging between the lens spacing by the size decision of lens beam angle and lens; (b) be the implementation synoptic diagram that adopts four lens, divide two groups, every group two lens, form 90 degree angles between group and the group, each lens forms a rectangle illumination zone, the stack back forms a criss-cross uniform illumination zone, and lenticular spacing is by the size decision of lens beam angle and lens.Each arrangement mode all can freely be expanded to reach required brightness value, and required expansion number depends on the illumination total value that will reach.

Figure 15 has provided the basic flow sheet of lens design: mainly comprise the initial parameter of determining lens design, according to conservation of energy principle go top long axis direction corresponding relation, according to refraction effect and energy corresponding relation calculate the major axis curve, according to conservation of energy principle further divide the energy relationship of short-axis direction, according to these parts of generation of optical surface behind total internal reflection and refraction effect and the major axis curve calculation minor axis curve.Only need vertical corresponding relation owing to finding the solution vertical curve, determine that horizontal corresponding relation also only needs to determine vertical corresponding relation earlier, and when the calculating horizontal curve, need to determine earlier vertical curve and horizontal corresponding relation.

Lens according to method for designing design of the present invention can have non-rotating symmetric shape, can form given Illumination Distribution design on an objective plane, its illumination plane has certain breadth length ratio or can simply be divided into some certain breadth length ratio zones that have; The time can consider less than 180 degree, equal 180 degree or in design, thereby can make full use of the energy of light source greater than the source light plane angles of 180 degree, thereby in theory and the target that in fact realizes saving the energy.According to the design concept requirement, on behalf of the led light source of future development trend, the size of light source will become a kind of suitable illumination Design light source and the actual light source that uses much smaller than the size of optical system.In addition, each light source unit that design constitutes can form one with the proportional Illumination Distribution of given illumination in whole field of illumination, therefore can be according to the concrete illumination requirement and the luminous flux level of light source, a plurality of light source units are lined up combination, given Illumination Distribution of common formation, and this arrangement is limited little, and design is free, flexible, simple.The present invention compares with existing lighting engineering, has characteristics efficient, energy-conservation and flexible and convenient to use, and in various illumination occasions, as road lighting, Landscape Lighting etc. all have broad application prospects.

Claims (2)

1. the LED three-dimensional optical design method of a given Illumination Distribution, form the non-imaging optical system of three-dimensional as light source, in given Illumination Distribution zone with light emitting diode, carry out the three-dimensional lens design with this optical system, the basic procedure of its three-dimensional lens design is: establish long axis direction X and short-axis direction Y on the illumination plane, set up coordinate system (X, Y), a given illumination plane initial point (x ₀, y ₀); The light source rising angle set up coordinate system (U, V), the initial value (u of a given light source rising angle ₀, v ₀); Given major axis zone of dispersion number N_L, minor axis zone of dispersion number N_W; Given light source height H; Given optical system height h; Given optical system material refractive index n and air refraction n ₀Given energy of light source and angle concern E (u, v), calculate the ranges of incidence angles of the energy area that the angular range of source light emergence angle and light source projects divide to the illumination plane of correspondence again according to the energy corresponding relation, iterate all characteristic point coordinates and the normal vector that the method for finding the solution is obtained optical system surface according to angle corresponding relation and utilization, thereby determine the surface of optical lens, it is characterized in that, the division of energy area is the geometric configuration at given Illumination Distribution zone on the illumination plane, follow law of conservation of energy, according to light refraction the light source surface is divided into corresponding energy area with the illumination plane at regional long axis direction, and carries out energy binned according to total internal reflection and the coefficient principle of refraction at short-axis direction;

The surface of described definite optical lens is according to above-mentioned given starting condition, adopts the method for variational integral to find the solution the surface curve of optical lens, be calculated as follows,

1) corresponding relation and the curve of calculating long axis direction: the illumination plane is divided into N_L zone by long axis direction, calculates each region energy weight E_L (i), the major axis coordinate x of i=0～N_L, zone boundary correspondence _i, i=0～N_L;

2) according to energy weight and given angle initial value calculating energy corresponding relation, determine that the angular divisions of long axis direction concerns u _i, i=0～N_L satisfies

3) the angle of incidence of light degree uX of calculating long axis direction zoning, illumination plane correspondence _i, i=0～N_L is according to itself and source light angle u _i, the corresponding relation of i=0～N_L calculates long axis direction refractive surface normal vector

Adopt iteration technique to calculate the characteristic point coordinates of refractive surface one by one again, obtain long axis direction refraction curve;

4) corresponding relation and the curve of calculating short-axis direction are on the basis that long axis direction is divided, to different major axis incident angle uX _i, i=0～N_L, with the illumination plane according to short-axis direction be divided into respectively N_W the zone, calculate each region energy weight E_W (i, j), i=1～N_L, j=1～N_W, the minor axis coordinate y of zone boundary correspondence (i, j), i=0～N_L, j=0～N_W

, and satisfy after superrefraction and the source light of outgoing through total internal reflection

V in the formula _j, v ' _jBe respectively only by the light angle of refraction outgoing with by total internal reflection and the coefficient light angle of refraction;

5) the angle of incidence of light degree vY of calculating short-axis direction zoning, illumination plane correspondence _{I, j}, i=0～N_L, j=0～N_W is then according to angle of incidence of light degree uX _i, i=0～N_L and vY _{I, j}, i=0～N_L, j=0～N_W and source light angle u _i, i=0～N_L and v _{I, j}, i=0～N_L, the corresponding relation of j=0～N_W, calculating optical system short-axis direction refractive surface normal vector respectively

I=0～N_L, j=0～N_W; The total internal reflection surface normal vector

I=0～N_L, j=0～N_W adopts iteration technique to calculate the characteristic point coordinates of refractive surface one by one again, obtains the optical system surface curve;

Described light source has the rectangle, ellipse of certain breadth length ratio, dolioform, spindle or their stack on the illumination plane in given Illumination Distribution zone.

2. according to the LED three-dimensional optical design method of the described given Illumination Distribution of claim 1, it is characterized in that the energy distribution in described given Illumination Distribution zone is that even distribution, Gaussian or Lorentz lorentz's type distribute.

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