CN102679266A - Implementation method of LED secondary light distribution lens with uniformly distributed rectangular light spots - Google Patents

Abstract

The invention discloses a method for realizing an LED secondary light distribution lens with uniform distribution of rectangular light spots, which includes: determining the light distribution of an LED light source that needs to be designed for light distribution; determining the rectangular area of illumination and the distance between the light source and the illumination area; Determine the lens material; divide the rectangular area into several line segments passing through the center of the rectangle; establish a one-to-one correspondence between any point on the line segment and the exit angle of the light source based on the law of energy conservation; solve the light distribution of the light distribution lens based on the law of refraction and the corresponding relationship surface. The invention realizes the secondary light distribution of the LED, the light spot is rectangular after the light distribution, and the light distribution is uniform.

Description

Realization method of LED secondary light distribution lens with uniform distribution of rectangular light spots

technical field

The present invention is applied to the field of optical technology, and in particular relates to a method for realizing an LED secondary light distribution lens with evenly distributed rectangular light spots.

Background technique

With the development trend of low-carbon energy-saving and green environmental protection, light-emitting diodes (LEDs) have attracted more and more attention due to their advantages of low energy consumption, high luminous efficiency and long life. As a new type of light source, LED is increasingly used in various lighting systems. However, LED lamps still have problems that need to be solved urgently. Due to the small size of the LED lamp, its light-emitting area is small and its directionality is strong, so the irradiation area is limited, and it needs to be distributed twice to meet the actual needs.

There are two methods currently used in light distribution: reflective light distribution and refraction light distribution. The reflective light distribution uses the principle of total reflection, so that the side of the light distribution lens becomes a total reflection surface, and all the light irradiated on the side is reflected back to the lens, thereby reducing the loss of side light energy and improving the utilization rate of light energy. However, the directionality of LED lights is single, the main light energy is concentrated in the middle part, and only the side is designed, so that most of the light energy concentrated in the middle part cannot be evenly distributed to the target lighting area, thus failing to meet the uniformity requirements.

Refractive light distribution adopts the principle of lens refraction, which can effectively disperse the light energy concentrated in the middle part to the target lighting area. At present, there are two main methods for realizing refractive light distribution: two-dimensional design and three-dimensional design. The two-dimensional design is to design the front surface and the rear surface of the secondary light distribution lens separately in two orthogonal directions, and then superimpose them. Although this method is easy to implement, it is only designed for two orthogonal lines. Others Most of the position errors are large, and the uniformity of the entire lens is poor.

The traditional three-dimensional design needs to establish a one-to-one correspondence between the entire refraction surface and the target lighting area, and carry out point-by-point design. The lens obtained by this method has better uniformity, but the design process is complicated and difficult to realize.

Contents of the invention

(1) Technical problems to be solved

In view of this, the technical problem to be solved by the present invention is: to overcome the shortcomings of the existing two-dimensional design and the complexity of the three-dimensional design, to provide a method for realizing the LED secondary light distribution lens with uniform distribution of rectangular light spots, and to make the curved surface of the lens The three-dimensional design is decomposed into several two-dimensional designs, which realizes the secondary light distribution of LED lights. The light spot is rectangular, and the light distribution in the entire rectangular area is uniform.

(2) Technical solution

In order to achieve the above object, the present invention provides a method for realizing an LED secondary light distribution lens with evenly distributed rectangular light spots, including:

Step 1: According to the provided LED light source information, determine the light distribution function I(θ) of the LED light source;

Step 2: Determine the length a, width b, and the distance h between the light source and the lighting area of the rectangular target lighting area according to specific needs;

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，

Step 4: Divide the rectangular target lighting area into several line segments passing through the center of the rectangle, and the length of the line segments 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,

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为目标照明区域的平均照度值；Step 5: According to the law of conservation of energy, establish step 4 to obtain the line segment

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 illuminance value of the target lighting area;

的对应关系，以及折射定律和几何关系，对配光曲面进行求解；透镜前表面为球面，使光线正入射进入透镜，减少反射损耗；后表面满足关系公式nsin(β+α)＝sin(β+θ_out)，其中tanβ为

方向上的曲线在

方向的斜率，θ_out为后表面出射光线在

方向的出射角。Step 6: Obtained according to the formula in step 4 and the formula in step 5 Any point on the lighting rectangle with the target

The corresponding relationship, as well as the law of refraction and geometric relationship, solve the light distribution surface; the front surface of the lens is a spherical surface, so that the light is incident on the lens and reduces the reflection loss; the rear surface satisfies the relational formula nsin(β+α)=sin(β +θ _out ), where tanβ is

The curve in the direction of

The slope of the direction, θ _out is the exit ray of the rear surface at

The direction of the exit angle.

In the above solution, the LED light source distribution function I(θ) described in step 1 is rotationally symmetric.

In the above solution, the shape of the rectangular target lighting area described in step 2 is a plane rectangle, and the LED light source is located at h above the center of the plane rectangle.

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

过矩形中心，线段长度满足公式

In the above scheme, the line segment described in step 4

Through the center of the rectangle, the length of the line segment satisfies the formula

与光源出射角θ满足公式∫I(θ)dθ＝∫Adρ。In the above scheme, any point on the target lighting area described in step 5

and the light source exit angle θ satisfy the formula ∫I(θ)dθ=∫Adρ.

In the above solution, the front surface of the secondary light distribution lens described in step 6 is a spherical surface, and the rear surface satisfies the formula nsin(β+α)=sin(β+θ _out ).

(3) Beneficial effects

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

1. The present invention adopts the realization method of refraction light distribution lens, and uses the law of energy conservation to establish a one-to-one correspondence between the points in the target lighting rectangular area and the outgoing angle of the LED light source, so that the light intensity distribution in the lighting area has a good Uniformity.

2. The present invention overcomes the shortcomings of large errors in the current two-dimensional design, and makes the two-dimensional design with only two orthogonal directions become a multi-directional two-dimensional design for the entire lens surface, solving the problem of orthogonal two-dimensional design. Design error in design.

3. Compared with the traditional three-dimensional light distribution design, the present invention decomposes the three-dimensional curved surface into multiple two-dimensional curves, which greatly reduces the design difficulty, and at the same time can obtain the same uniformity as the traditional three-dimensional light distribution design.

Description of drawings

Fig. 1 is the schematic structural diagram of the LED secondary light distribution lens realized according to the present invention, wherein 1 is the designed back surface, 2 is the spherical front surface, and 3 is the position of the LED light source;

Fig. 2 is the front view of the spherical front surface in the LED secondary light distribution lens realized according to the present invention;

Fig. 3 is the front view of the spherical rear surface in the LED secondary light distribution lens realized according to the present invention;

Figure 4 is the circular light spot of the LED light source before the secondary light distribution lens is added;

Figure 5 shows the rectangular light spot obtained after adding a secondary light distribution 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.

The implementation method of the LED secondary light distribution lens with evenly distributed rectangular light spots provided by the present invention comprises the following steps:

Step 1: According to the provided LED light source information, determine that the light distribution function of the LED light source satisfies the relationship: I(θ)=80*cos ² θ;

Step 2: Determine the length a=30m, width b=16m of the rectangular target lighting area as required, and the distance h=10m between the light source and the lighting area;

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

在本实施例中

Step 4: Divide the rectangular lighting area into several line segments passing through the center of the rectangle, and the length of the line segments 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,

In this example

上任一点

与LED光源出射角

的一一对应关系；其中ρ为点

与矩形中心的距离，A为目标照明区域的平均照度值；Step 5: Create a line segment according to the formula ∫I(θ)dθ=∫Adρ

Take office a little

Outgoing angle with LED light source

One-to-one correspondence; where ρ is a point

The distance from the center of the rectangle, A is the average illuminance value of the target lighting area;

Step 6: Substituting the relationship obtained in step 5 into the formula nsin(β+α)=sin(β+θ _out ) to solve the light distribution surface in different The slope tanβ of the direction, so as to obtain the data of the entire rear surface of the lens that plays the role of light distribution, 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, the front surface of the lens is spherical, as shown in Figure 1 and Figure 2, and the LED light source is located at the center of the sphere, as shown in Figure 1 3 , light enters the lens at normal incidence on the front surface, reducing reflection loss.

Step 7: Assemble the lens obtained in step 6 with the LED light source in step 1 to obtain a spot shape as shown in Figure 5, while the spot shape of the bare lamp without the lens is circular (as shown in Figure 4). It can be seen that, The LED secondary light distribution lens realized according to the invention can obtain rectangular light spots, 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. A method for realizing an LED secondary light distribution lens that is uniformly distributed in a rectangular spot, characterized in that it comprises: Step 1: According to the provided LED light source information, determine the light distribution function I(θ) of the LED light source; Step 2: Determine the length a, width b, and the distance h between the light source and the lighting area of the rectangular target lighting area according to specific needs; Step 3: Determine the refractive index n of the lens material according to the lens material; Step 4: Divide the rectangular target lighting area into several line segments passing through the center of the rectangle, and the length of the line segments 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,

Step 5: According to the law of conservation of energy, establish step 4 to obtain the line segment

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 illuminance value of the target lighting area; Step 6: Obtained according to the formula in step 4 and the formula in step 5

Any point on the lighting rectangle with the target

The corresponding relationship, as well as the law of refraction and geometric relationship, solve the light distribution surface; the front surface of the lens is a spherical surface, so that the light is incident on the lens and reduces the reflection loss; the rear surface satisfies the relational formula nsin(β+α)=sin(β +θ _out ), where tanβ is

The curve in the direction of

The slope of the direction, θ _out is the exit ray of the rear surface at The direction of the exit angle. 2. The method for realizing the LED secondary light distribution lens with uniform distribution of rectangular light spots according to claim 1, characterized in that the LED light source distribution function I(θ) described in step 1 is rotationally symmetric. 3. The method for realizing the LED secondary light distribution lens with uniform distribution of rectangular light spots according to claim 1, wherein the shape of the rectangular target lighting area described in step 2 is a plane rectangle, and the LED light source is located on the plane h above the center of the rectangle. 4. The realization method of the LED secondary light distribution lens with uniform distribution of rectangular light spots according to claim 1, characterized in that the lens material described in step 3 is light-transmitting material PMMA or glass. 5. The method for realizing the LED secondary light distribution lens with uniform distribution of rectangular light spots according to claim 1, characterized in that the line segment described in step 4

Through the center of the rectangle, the length of the line segment satisfies the formula

6. The method for realizing the LED secondary light distribution lens with uniform distribution of rectangular light spots according to claim 1, characterized in that any point on the target illumination area described in step 5

and the light source exit angle θ satisfy the formula ∫I(θ)dθ=∫Adρ. 7. The realization method of the LED secondary light distribution lens that is uniformly distributed in rectangular light spots according to claim 1, wherein the front surface of the secondary light distribution lens described in step 6 is a spherical surface, and the rear surface satisfies the formula nsin(β+α)=sin(β+ _θout ).

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