CN102679265B - Method for realizing light beam dodging control by utilizing free-form surface lens - Google Patents

Abstract

The invention discloses a method for realizing light uniformity control of a beam by using a free-form surface lens, comprising: step 1: determining the light distribution form of a light source that requires uniform light control; step 2: determining the position information of the area for realizing uniform light control; 3: Determine the lens material; Step 4: Based on the law of energy conservation, divide the uniform light control area into several sub-areas; Step 5: Establish a one-to-one correspondence between any sub-area in Step 4 and the exit angle of the light source; Step 6: Based on The law of refraction and the corresponding relationship of steps 4 and 5 solve the surface shape of the free-form surface lens. The invention realizes uniform light control of light beams for arbitrary light sources, and the light beams passing through the free-form surface lens present uniform light spots of arbitrary shapes.

Description

A Method of Using Freeform Surface Lens to Realize Beam Homogenization Control

technical field

The invention relates to the technical field of applied optics, in particular to a method for realizing beam uniformity control by using a free-form surface lens.

Background technique

At present, the light sources emitted by most light source generating devices are non-uniform. For example, the light output by a laser satisfies a Gaussian distribution, and the light output by an LED satisfies a Lambertian distribution. However, a light source with better uniformity is required in many occasions, or a The light emitted by the light source is controlled in a required specific shape area, which requires uniform light control on the light source to meet the actual needs.

At present, there are the following methods for uniform light control: (1) microlens uniform light array. This method is mainly composed of a series of orthogonally distributed tiny lenses with a specific surface shape to form an array. After the beam passes through the array, the emitted light can be superimposed on each other to produce a uniform light effect. This method has high requirements on the processing and manufacturing level of the lens, and the structure is complex and the cost is high. (2) Complex lens system. A combination of a series of lenses is used to form a uniform light effect. This method has a better uniform light effect, but the structure is complicated and the cost is high.

In addition, none of the above methods can control the light beam emitted by the light source within a specific shaped area. In view of the above points, the present invention proposes a new design method for light uniformity control based on a free-form surface lens.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is: to overcome the complexity of the existing uniform light system and the problem that the light beam cannot be controlled, and to provide a new design method for uniform light control based on a free-form surface lens, which only uses one lens to realize Uniform light for any light source, light and make the exit spot any desired shape.

(2) Technical solutions

In order to achieve the above object, the present invention provides a method of utilizing a free-form surface lens to realize beam uniformity control, the method comprising:

Step 1: According to the provided light source information, determine the light distribution function of the light source

Step 2: Determine the shape and position of the target lighting area according to specific needs, wherein the shape of the target lighting area is a rectangle;

Step 3: Determine the refractive index n of the lens material according to the lens material;

其中

为过矩形中心的线段与矩形的长边a所成的角，即

Step 4: Divide the rectangular area into several sub-areas passing through the center of the rectangle, and the grid length corresponding to each sub-area satisfies the formula

in

is the angle formed by the line segment passing through the center of the rectangle and the long side a of the rectangle, that is

上任一点

与光源出射角θ的一一对应关系，其关系如公式∫I(θ)dθ＝∫Adρ，其中ρ为点

与矩形中心的距离，A为目标区域的平均光强值；Step 5: According to the law of energy conservation, establish step 4 to obtain the regional grid

Take office a little

One-to-one correspondence with the light source exit angle θ, the relationship is as in the formula ∫I(θ)dθ=∫Adρ, where ρ is a point

The distance from the center of the rectangle, A is the average light intensity value of the target area;

与目标矩形区域上任一点

的对应关系，根据折射定律对曲面面型进行求解；透镜前表面为平面，使光线正入射进入透镜，减少反射损耗；后表面每一网格上的点的法线满足关系公式

其中

为自由曲面透镜上某一网格的法线与光源的θ和方向的夹角，

为目标区域上某一网格的法线与光源的θ和

方向的夹角，

为光源发出的该条光线在θ和

方向上的夹角，n为透镜的折射率。Step 6: Obtained according to the formula in step 4 and the formula in step 5

and any point on the target rectangular area

According to the law of refraction, the surface type is solved; the front surface of the lens is a plane, so that the light is incident on the lens and reduces the reflection loss; the normal of each point on the rear surface satisfies the relational formula

in

is the normal of a grid on the free-form surface lens and the θ sum of the light source angle of direction,

is the normal of a mesh on the target area and the θ sum of the light source

angle of direction,

The ray emitted by the light source is at θ and

The included angle in the direction, n is the refractive index of the lens.

是旋转对称的。In the above scheme, the light source distribution function described in step 1

is rotationally symmetric.

In the above solution, the length and width of the rectangle in step 2 are a and b respectively, and the light source is located at h in front of the center of the rectangle.

In the above scheme, the lens material described in step 3 is light-transmitting material PMMA or glass.

满足公式

In the above scheme, the grid described in step 4 passes through the center of the rectangle, and the length

satisfy the formula

与光源出射角θ满足公式In the above scheme, the points described in step 5

and light source exit angle θ satisfy the formula

∫I(θ)dθ=∫Adρ.

In the above scheme, the front surface of the free-form surface lens described in step 6 is a plane, and the normal vector of each grid on the back surface satisfies the formula

(3) Beneficial effects

The advantage of the present invention compared with prior art is:

(1) The present invention adopts the design method of a single lens to realize uniform light control, and has simple structure, easy processing and low cost.

(2) The present invention adopts the free-form surface lens design method, utilizes the law of energy conservation to establish a one-to-one correspondence between points in the target area and the light source exit angles, so that for a light source with any light intensity distribution, the light intensity distribution in the target area All have good uniformity.

(3) The present invention realizes the control of any light source in a target area of any shape, and well realizes the restriction effect on light distribution.

Description of drawings

Fig. 1 is a schematic structural view of a free-form surface lens provided according to the present invention, 1 is the designed rear surface, and 2 is the front surface;

Fig. 2 is the front view of the rear surface of the free-form surface lens shown in Fig. 1;

Fig. 3 is a side view of the rear surface of the free-form surface lens shown in Fig. 1;

Figure 4 shows the corresponding relationship between the light source and the target area;

Figure 5 is the exit spot of the light source before adding a free-form surface lens;

Figure 6 shows the rectangular spot obtained after adding a free-form surface lens.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

A method for realizing beam uniformity control by using a free-form surface lens, the method comprising the following steps:

Step 1: According to the provided light source information, determine that the light distribution function of the light source satisfies the Gaussian distribution, with a diameter of 10mm;

Step 2: Determine the target dodging area as needed. This example is a rectangle with length a=30mm, width b=16mm, and the distance between the light source and the target area h=10mm;

Step 3: select the lens material as PMMA, and the refractive index of this material is n=1.49;

本例中

Step 4: Divide the rectangular lighting area into several grids passing through the center of the rectangle, and the length of the grid line segment satisfies formula 1, namely in is the angle formed by the line segment passing through the center of the rectangle and the long side a of the rectangle, that is

In this example

与光源出射角

的一一对应关系(如图4)；其中ρ为点与矩形中心的距离，A为目标区域的平均光强值；Step 5: Create a line segment according to the formula ∫I(θ)dθ=∫Adρ Take office a little

and light source exit angle

One-to-one correspondence (as shown in Figure 4); where ρ is a point The distance from the center of the rectangle, A is the average light intensity value of the target area;

其中

为自由曲面透镜上某一网格的法线与光源的θ和

方向的夹角，

为目标区域上某一网格的法线与光源的θ和

方向的夹角，

为光源发出的该条光线在θ和

方向上的夹角，n为透镜的折射率，求解出配光曲面在不同θ，

方向的法线，进而求解曲面上每个网格的坐标数据，最后生成透镜实体。得到的透镜后表面的面形如图1中1和图3所示，透镜前表面为平面，如图1中2和图2所示，光线在前表面正入射进入透镜，减少反射损耗。Step 6: Substitute the relationship obtained in step 5 into formula (3), namely

in

is the normal of a grid on the free-form surface lens and the θ sum of the light source

angle of direction,

is the normal of a mesh on the target area and the θ sum of the light source

angle of direction,

The ray emitted by the light source is at θ and

The included angle in the direction, n is the refractive index of the lens, and the light distribution surface is solved at different θ,

The normal of the direction, and then solve the coordinate data of each mesh on the surface, and finally generate the lens entity. The surface shape of the rear surface of the obtained lens is shown in Figure 1 and Figure 3, and the front surface of the lens is a plane, as shown in Figure 1 and Figure 2, and the light is incident on the front surface and enters the lens to reduce reflection loss.

Step 7: Simulate the lens obtained in step 6 and the light source in step 1, and the spot shape obtained is shown in Figure 6, while the spot shape of the light source without the lens is Gaussian distribution circle (Figure 5), it can be seen that , the free-form surface lens designed according to the present invention can obtain a rectangular spot, and the illuminance is evenly distributed in the rectangular area.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (7)

1. utilize free-form surface lens to realize a method for the even photocontrol of light beam, it is characterized in that, the method comprises:

Step 1: according to the light source data providing, determine the light distribution function of light source θ and

for point

solid angle;

Step 2: determine according to specific needs shape and the position in target illumination region, wherein this target illumination region is shaped as rectangle;

Step 3: according to lens material, determine the refractive index n of lens material;

Step 4: rectangular area is divided into some subregions of crossing rectangular centre, and Gridding length corresponding to every sub regions meets formula

wherein, the length that a and b are rectangle and wide,

Step 5: according to law of conservation of energy, establishment step 4 obtains area grid

upper any point with the one-to-one relationship of light source angle of emergence θ, its relation is as formula

wherein ρ is a little

with the distance of rectangular centre, the average intensity value that A is target area;

Step 6: obtain according to formula in formula and step 5 in step 4

with any point on target rectangle region

corresponding relation, according to the law of refraction, curved surface face type is solved; Lens front surface is plane, makes light normal incidence enter lens, reduces reflection loss; The normal of the point on each grid of rear surface meets relation formula

wherein

for the normal of a certain grid on free-form surface lens and the θ of light source and the angle of direction,

for the normal of a certain grid on target area and the θ of light source and

the angle of direction,

this light sending for light source at θ and

angle in direction, the refractive index that n is lens.

2. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the distribution of light sources function described in step 1

rotational symmetric.

3. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the length of rectangle described in step 2 and wide a and the b of being respectively, and light source is positioned at h place, rectangular centre the place ahead.

4. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the lens material described in step 3 is light transmissive material PMMA or glass.

5. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the grid described in step 4 is crossed rectangular centre, length

meet formula

6. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the point described in step 5

θ meets formula with the light source angle of emergence

7. the method for utilizing free-form surface lens to realize the even photocontrol of light beam according to claim 1, is characterized in that, the front surface of the free-form surface lens described in step 6 is plane, and the normal vector of each grid of rear surface meets formula

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