CN103912844A - LED uniform-collimation optical system - Google Patents

Abstract

The invention relates to the technical field of LED lighting collimation optical system, in particular to an LED uniform-collimation optical system comprising a first free-form surface lens and a second free-form surface lens which are coaxial. The first and second free-form surface lenses are 0.01m-0.1m in spacing. The first free-form surface lens comprises a first surface which is a rotational symmetric free-form surface, a second surface which is a rotational symmetric free-form surface, a third surface which is a rotational symmetric paraboloid, a fifth surface which is a rotational symmetric free-form surface, and a fourth surface which is a cylindrical surface used for connecting the third surface and the fifth surface. The second free-form surface lens comprises three surfaces; the first surface is a free-form surface and controls the direction of light from the second free-from surface lens; the second surface and the third surface are a connecting surface and a light emission face of the second free-form surface lens respectively. The system is well capable of controlling the light and capable of shaping the LED light into uniform round light spots.

Description

LED is the optical system of collimation evenly

Technical field

The present invention relates to the collimating optical system technical field of LED illumination, be specifically related to the evenly optical system of collimation of a kind of LED.

Technical background

LED is as a kind of new type light source, and due to its high light efficiency, the life-span is long, nonhazardous etc., and advantage makes it the perfect replacer who becomes traditional light source such as incandescent lamp, fluorescent lamp.But because the light distribution of LED is that circular lambert's type distributes, if directly apply to illumination, can in target face, form very inhomogeneous Illumination Distribution, cannot meet the requirement of various illumination occasions to light fixture optical property.In order to make LED better be applied to lighting field, need designs secondary optics system to redistribute the light distribution of LED, it can be formed evenly or other specific Illumination Distribution in target face.

In the illumination such as optic communication, photoelectronic imaging application scenario, not only need Uniform Illumination, also needing light is collimated light.For this reason, at least need the direction of two optical surface control LED light, wherein first Surface forming is uniformly distributed, and second curved surface changes radiation direction makes it collimation.Chinese invention patent application description CN103148443A has proposed a kind of for obtaining two free form surface thick lenses of even collimated light beam and the method for designing of array thereof.This thick lens comprises two free form surfaces, can obtain the even collimated ray for LED light source.But owing to there is total reflection phenomenon between different refractivity medium, therefore this lens can not be collected whole light of LED, therefore can cause the light efficiency of lens not high enough, affect the propagation distance of whole system.

Summary of the invention

The object of the invention is to need for optic communication, photoelectronic imaging etc. the occasion of collimated illumination, design a kind of evenly optical system of collimation of LED that realizes the even collimated illumination of circular light spot, this optical system can be collected whole light of LED, has higher light efficiency.

For achieving the above object, the designed LED of the present invention is the optical system of collimation evenly, comprises the first free-form surface lens and second free-form surface lens of coaxial setting, and described the first free-form surface lens and the second free-form surface lens spacing are 0.01m-0.1m;

Described the first free-form surface lens comprises first surface, is Rotational Symmetry free form surface, for the light refraction that LED is sent, make refraction after light ray parallel in z axle; The second curved surface, is Rotational Symmetry free form surface, for the light refraction that LED is sent, makes the light after refraction become the light sending with spot light on x axle and overlap; The 3rd curved surface, for rotation is to parabola, paraboloidal focus is the virtual optical source point of the second curved surface refracted ray; The 5th curved surface, for Rotational Symmetry free form surface, for controlling the light through being parallel to z axle after first surface, the second curved surface and the 3rd curved surface, the light that makes this bundle be parallel to z axle is forming uniform Illumination Distribution on any disk vertical with z axle after the 5th curved surface in space; And the 4th curved surface, be the face of cylinder, for connecting the 3rd curved surface and the 5th curved surface;

Described the second free-form surface lens, is made up of three curved surfaces, and wherein first surface is free form surface, the direction of the light beam that control the second free-form surface lens sends, and the second curved surface and the 3rd curved surface are respectively connection curved surface and the beam projecting face of lens.

Further, the coordinate of putting on described first surface and the second curved surface is calculated by following formula: set the initial point of the first free form surface, obtain its outline line by following formula iteration:

$\left\{\begin{array}{c}{x}_i=\frac{z_{i-1}+x_{i-1}k}{\cot {\mathrm{\θ}}_i+k}\\ z_i=x_i\cot {\mathrm{\θ}}_i\end{array}\right.---\left(1\right)$

Wherein (x _i, z _i) be the coordinate of the calculative point of current iteration, (x _i-1, z _i-1) be more front coordinate, (N _x, N _z) be more front normal vector coordinate, after obtaining contour curve, can obtain whole curved surface take z axle as symmetry axis rotating 360 degrees.

Again further, the z axial coordinate of the coordinate of described the 5th surface points and free form surface obtains by Simultaneous Iteration, establishes the coordinate of putting on the 5th curved surface and free form surface and is respectively (x ₁, y ₁, z ₁) and (x ₂, y ₂, z ₂), the angular region of light source is divided into M × N part, the luminous flux in every part is identical, calculates x, the y axial coordinate of the 5th corresponding curved surface.The cross section of outgoing hot spot is divided into M × N the unit that area is equal simultaneously, and calculates x, the y axial coordinate of corresponding points on corresponding free form surface, the initial point of selected two curved surfaces, solves by the method for iteration the z axial coordinate of putting on initial skeleton curve and is:

$\left\{\begin{array}{c}{z}_{1,i}=\frac{-(x_{1,i}-x_{1,i-1})N_{1x}-(y_{1,i}-y_{1,i-1})N_{1y}}{N_{1z}}+z_{1,i-1}\\ z_{2,i}=\frac{-(x_{2,i}-x_{2,i-1})N_{2x}-(y_{2,i}-y_{2,i-1})N_{2y}}{N_{2z}}+z_{2,i-1}\end{array}\right.---\left(2\right)$

Wherein (x _{1, i}, y _{1, i}, z _{1, i}) and (x _{2, i}, y _{2, i}, z _{2, i}) be the coordinate of putting on the 5th curved surface of calculative the first free-form surface lens of current iteration and the first surface of the second free-form surface lens, (x _{1, i-1}, y _{1, i-1}, z _{1, i-1}) and (x _{2, i-1}, y _{2, i-1}, z _{2, i-1}) be corresponding before any coordinate, (N _1x, N _1y, N _1z) and (N _2x, N _2y, N _2z) be more front normal vector coordinate, obtaining obtaining next skeleton curve by (2) formula iteration after initial skeleton curve, after obtaining all skeleton curves, obtain the 5th curved surface and the first free form surface by the mode of setting-out.

Design LED of the present invention evenly collimates secondary optical system, there is good light control ability, the light of LED can be shaped as to uniform circular light spot, because LED plane of light incidence collimation time has adopted fully reflecting surface, therefore can collect the light of whole LED and can not reduce because of total reflection the light efficiency of optical system.

Accompanying drawing explanation

Fig. 1 is concrete overall structure schematic diagram of implementing of the present invention.

The side view of Fig. 2 Fig. 1.

The cutaway view of Fig. 3 Fig. 2.

Fig. 4 is the side view of the second free-form surface lens (2) in Fig. 1.

Fig. 5 is the cutaway view of Fig. 4.

Fig. 6 .1 is the simulation result figure that is embodied in the Illumination Distribution in target face in optical design software;

Fig. 6 .2 is embodied in optical design software in outgoing hot spot target face the simulation result figure of Illumination Distribution on two centre coordinate axles;

In figure, 1-the first free-form surface lens, 11-first surface; 12-the second curved surface; 13-the 3rd curved surface; 14-the 4th curved surface; 15-the 5th curved surface; 2-the second free-form surface lens; 21-free form surface; 22-connects curved surface; 23-beam projecting face.

The specific embodiment

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail:

LED shown in Fig. 1-4 is the optical system of collimation evenly, comprises that the first free-form surface lens 1 of coaxial setting and the second free-form surface lens 2, the first free-form surface lens 1 and the second free-form surface lens 2 spacing are 0.01m-0.1m; The first free-form surface lens 1 comprises first surface 11, is Rotational Symmetry free form surface, for the light refraction that LED is sent, make refraction after light ray parallel in z axle, the LED light of this free form surface control and the angle of z axle are determined by the refractive index of lens material; The second curved surface 12, is Rotational Symmetry free form surface, for the light refraction that LED is sent, makes the light after refraction become the light sending with spot light on x axle and overlap; The 3rd curved surface 13, for rotation is to parabola, paraboloidal focus is the virtual optical source point of the second curved surface refracted ray; The 5th curved surface 15, for Rotational Symmetry free form surface, for controlling the light through being parallel to z axle after first surface 11, the second curved surface 12 and the 3rd curved surface 13, the light that makes this bundle be parallel to z axle is forming uniform Illumination Distribution on any disk vertical with z axle after the 5th curved surface 15 in space; And the 4th curved surface 14, be the face of cylinder, for connecting the 3rd curved surface 13 and the 5th curved surface 15; The second free-form surface lens 2, is made up of three curved surfaces, and wherein first surface is free form surface 21, the direction of the light beam that control the second free-form surface lens 2 sends, and the second curved surface and the 3rd curved surface are respectively connection curved surface 22 and the beam projecting face 23 of lens.

On first surface 11 and the second curved surface 12, the coordinate of point is calculated by following formula: set the initial point of the first free form surface, obtain its outline line by following formula iteration:

$\left\{\begin{array}{c}{x}_i=\frac{z_{i-1}+x_{i-1}k}{\cot {\mathrm{\θ}}_i+k}\\ z_i=x_i\cot {\mathrm{\θ}}_i\end{array}\right.---\left(3\right)$

Wherein (x _i, z _i) be the coordinate of the calculative point of current iteration, (x _i-1, z _i-1) be more front coordinate, (N _x, N _z) be more front normal vector coordinate, after obtaining contour curve, can obtain whole curved surface take z axle as symmetry axis rotating 360 degrees.

The z axial coordinate simultaneous of the coordinate of the 5th 15, curved surface and free form surface 21 is asked for and is obtained, and the coordinate of establishing point on the 5th curved surface 15 and free form surface 21 is respectively (x ₁, y ₁, z ₁) and (x ₂, y ₂, z ₂), the angular region of light source is divided into M × N part, the luminous flux in every part is identical, calculates x, the y axial coordinate of the 5th corresponding curved surface 15.The cross section of outgoing hot spot is divided into M × N the unit that area is equal simultaneously, and calculates x, the y axial coordinate of corresponding points on corresponding free form surface 21, the initial point of selected two curved surfaces, solves by the method for iteration the z axial coordinate of putting on initial skeleton curve and is:

$\left\{\begin{array}{c}{z}_{1,i}=\frac{-(x_{1,i}-x_{1,i-1})N_{1x}-(y_{1,i}-y_{1,i-1})N_{1y}}{N_{1z}}+z_{1,i-1}\\ z_{2,i}=\frac{-(x_{2,i}-x_{2,i-1})N_{2x}-(y_{2,i}-y_{2,i-1})N_{2y}}{N_{2z}}+z_{2,i-1}\end{array}\right.---\left(4\right)$

Wherein (x _{1, i}, y _{1, i}, z _{1, i}) and (x _{2, i}, y _{2, i}, z _{2, i}) be the coordinate of putting on the 5th curved surface of calculative the first free-form surface lens of current iteration and the first surface of the second free-form surface lens, (x _{1, i-1}, y _{1, i-1}, z _{1, i-1}) and (x _{2, i-1}, y _{2, i-1}, z _{2, i-1}) be corresponding before any coordinate, (N _1x, N _1y, N _1z) and (N _2x, N _2y, N _2z) be more front normal vector coordinate, obtaining obtaining next skeleton curve by (2) formula iteration after initial skeleton curve, after obtaining all skeleton curves, obtain the 5th curved surface 15 and free form surface 21 by the mode of setting-out.

As a specific embodiment of the present invention, LED is positioned at the origin of coordinates.This optical system comprises two parts, the first free-form surface lens 1 and the second free-form surface lens 2.

Fig. 2 and Fig. 3 are side-looking and the cutaway views of the first free-form surface lens 1 in Fig. 1, and wherein first surface 11, the second curved surface 12, the 3rd curved surface 13 are planes of incidence of LED light, and object is that the spherical wave collimation that LED is sent is the plane wave vertical with z axle.

First surface 11 is by the light refraction from LED to parallel with z axle, and this curved surface is rotational symmetric, only need calculate a contour curve while therefore calculating, then revolves to turn around around z axle to obtain the face type of first surface 11.While calculating contour curve, first determine the coordinate figure of initial point, initial point is the intersection point of curved surface and z axle, calculates the coordinate figure of putting on contour curve by the mode of iteration.Make current known point (x _i-1, z _i-1) normal vector be N=(N _x, N _z), under the contour curve that calculate, any corresponding incident ray and the angle of z axle are θ _i, lower any coordinate figure (x _i, z _i) be:

$\left\{\begin{array}{c}{x}_i=\frac{z_{i-1}+x_{i-1}k}{\cot {\mathrm{\θ}}_i+k}\\ z_i=x_i\cot {\mathrm{\θ}}_i\end{array}\right.---\left(5\right)$

Wherein k=N _x/ N _z.The z coordinate figure of implementing the initial point of mean camber S11 at this is 5mm, and the corresponding LED light of curved edges and z axle clamp angle are 30 °.

The object of the second curved surface 12 be make the reverse extending line of light that LED the sends emergent ray after this curved surface refraction meet at x axle a bit, thereby obtain a virtual optical source point.The initial point of the second curved surface 12 is the marginal point of first surface 11, uses equally (1) when calculating.

The focus of the 3rd curved surface 13 is the virtual optical source point that the second curved surface 12 is created, and utilizes total reflection principle, by the light reflection from the second curved surface 12 to z axle parallel direction.

The energy by the plane wave through after curved surface first surface 11, the second curved surface 12 and the 3rd curved surface 13 of the 5th curved surface 15 is redistributed, and makes certain center in space form and be uniformly distributed on z axle and on the disk vertical with z axle.On the 4th curved surface 14, the coordinate account form of point is for utilizing the conservation of energy, incident wavefront and target circle plane are divided into the grid that energy is equal, determine the corresponding relation between mesh point according to space topological, recycling (1) formula can be calculated the coordinate of point on the 5th curved surface 15.Because the 5th curved surface 15 is rotational symmetric, therefore only need to calculate contour curve can obtain curved surface face type.In this enforcement, this disk is positioned at z=70mm place, and radius is 20mm, and the initial point of the 5th curved surface 15 is (0,0,17.36).

After calculating all curved surfaces of the first free-form surface lens 1, height is 20.55mm, and wide is 32.44mm.The space height forming between first surface 11 and the second curved surface 12 is 5mm, and wide is 4.9mm, for placing LED light source.

Fig. 4 and Fig. 5 are side-looking and the cutaway views of the second free-form surface lens 12 in Fig. 1.The second free-form surface lens 2 in this enforcement is made up of free form surface 21, connection curved surface 22, beam projecting face 23.

Joint face and beam projecting face that to connect curved surface 22, beam projecting face 23 be lens, do not change the exit direction of light in actual use.

The object of free form surface 21 be by the refraction of optical beam from the first free-form surface lens 1 to z axle parallel direction.Adopt Snell's law to calculate the coordinate of putting on free form surface, computational methods still adopt formula (1).

Fig. 6 .1 and Fig. 6 .2 are the simulation results that is originally implemented in the outgoing hot spot obtaining in optical design software, obtain by 1,000,000 light of trace, wherein Fig. 6 .1 is the Illumination Distribution in target face, in figure, gray value size is directly proportional to brightness value, and Fig. 6 .2 is the Illumination Distribution on two centre coordinate axles in target face.Simulation result shows that the optical efficiency of the lens combination of this enforcement is 80.82%.Illuminance uniformity on x axle and y axle is 75%, good uniformity.

Claims (3)

1. the evenly optical system of collimation of a LED, it is characterized in that comprising: first free-form surface lens (1) of coaxial setting and the second free-form surface lens (2), described the first free-form surface lens (1) and the second free-form surface lens (2) spacing are 0.01m-0.1m;

Described the first free-form surface lens (1) comprises first surface (11), is Rotational Symmetry free form surface, for the light refraction that LED is sent, make refraction after light ray parallel in z axle; The second curved surface (12), is Rotational Symmetry free form surface, for the light refraction that LED is sent, makes the light after refraction become the light sending with spot light on x axle and overlap; The 3rd curved surface (13), for rotation is to parabola, paraboloidal focus is the virtual optical source point of the second curved surface refracted ray; The 5th curved surface (15), for Rotational Symmetry free form surface, be used for controlling the light that is parallel to afterwards z axle through first surface (11), the second curved surface (12) and the 3rd curved surface (13), the light that makes this bundle be parallel to z axle is forming uniform Illumination Distribution on any disk vertical with z axle after the 5th curved surface (15) in space; And the 4th curved surface (14), be the face of cylinder, for connecting the 3rd curved surface (13) and the 5th curved surface (15);

Described the second free-form surface lens (2), formed by three curved surfaces, wherein first surface is free form surface (21), the direction of the light beam that control the second free-form surface lens (2) sends, and the second curved surface and the 3rd curved surface are respectively connection curved surface (22) and the beam projecting face (23) of lens.

2. the evenly optical system of collimation of LED according to claim 1, it is characterized in that: the coordinate of the upper point of described first surface (11) and the second curved surface (12) is calculated by following formula: set the initial point of the first free form surface, obtain its outline line by following formula iteration:

$\left\{\begin{array}{c}{x}_i=\frac{z_{i-1}+x_{i-1}k}{\cot {\mathrm{\θ}}_i+k}\\ z_i=x_i\cot {\mathrm{\θ}}_i\end{array}\right.---\left(1\right)$

Wherein (x _i, z _i) be the coordinate of the calculative point of current iteration, (x _i-1, z _i-1) be more front coordinate, (N _x, N _z) be more front normal vector coordinate, after obtaining contour curve, can obtain whole curved surface take z axle as symmetry axis rotating 360 degrees.

3. the evenly optical system of collimation of LED according to claim 1, it is characterized in that: described the 5th coordinate of curved surface (15) point and the z axial coordinate simultaneous of free form surface (21) are asked for and obtained, the coordinate of establishing the upper point of the 5th curved surface (15) and free form surface (21) is respectively (x ₁, y ₁, z ₁) and (x ₂, y ₂, z ₂), the angular region of light source is divided into M × N part, the luminous flux in every part is identical, calculates x, the y axial coordinate of the 5th corresponding curved surface (15).The cross section of outgoing hot spot is divided into M × N the unit that area is equal simultaneously, and calculate x, the y axial coordinate of the upper corresponding points of corresponding free form surface (21), the initial point of selected two curved surfaces, solves by the method for iteration the z axial coordinate of putting on initial skeleton curve and is:

$\left\{\begin{array}{c}{z}_{1,i}=\frac{-(x_{1,i}-x_{1,i-1})N_{1x}-(y_{1,i}-y_{1,i-1})N_{1y}}{N_{1z}}+z_{1,i-1}\\ z_{2,i}=\frac{-(x_{2,i}-x_{2,i-1})N_{2x}-(y_{2,i}-y_{2,i-1})N_{2y}}{N_{2z}}+z_{2,i-1}\end{array}\right.---\left(2\right)$

Wherein (x _{1, i}, y _{1, i}, z _{1, i}) and (x _{2, i}, y _{2, i}, z _{2, i}) be the coordinate of putting on the 5th curved surface of calculative the first free-form surface lens of current iteration and the first surface of the second free-form surface lens, (x _{1, i-1}, y _{1, i-1}, z _{1, i-1}) and (x _{2, i-1}, y _{2, i-1}, z _{2, i-1}) be corresponding before any coordinate, (N _1x, N _1y, N _1z) and (N _2x, N _2y, N _2z) be more front normal vector coordinate, obtaining obtaining next skeleton curve by (2) formula iteration after initial skeleton curve, after obtaining all skeleton curves, obtain the 5th curved surface (15) and free form surface (21) by the mode of setting-out.