CN107816701A - A kind of downward back optical lens with non-smooth curve - Google Patents

本发明提供一种具有非平滑曲线的直下式背光透镜，该透镜为旋转对称体，该透镜包括底面、入射面和出射面，光线自入射面射入透镜内，自出射面射出透明外；该旋转对称体的对称轴为光轴Z，穿过Z轴的截面沿Z轴的一侧与入射面的相交线为入射曲线C1，与出射面的相交线为出射曲线C2；以Z轴为Y轴建立直角坐标系，X轴位于截面上，则C1和C2中至少有一条曲线为y＝Cj(x)。

The invention provides a direct-type backlight lens with non-smooth curves, the lens is a rotationally symmetrical body, the lens includes a bottom surface, an incident surface and an exit surface, light enters the lens from the incident surface, and exits the transparent exterior from the exit surface; The axis of symmetry of the rotationally symmetric body is the optical axis Z, the intersection line between the side of the Z axis and the incident surface along the Z axis is the incident curve C1, and the intersection line with the exit surface is the exit curve C2; the Z axis is Y Axes establish a rectangular coordinate system, and the X-axis is located on the section, then at least one of the curves in C1 and C2 is y=Cj(x).

一种具有非平滑曲线的直下式背光透镜A direct backlit lens with non-smooth curve

技术领域technical field

本发明属于光学器件领域，具体涉及一种具有非平滑曲线的直下式背光透镜。The invention belongs to the field of optical devices, and in particular relates to a straight-down backlight lens with non-smooth curves.

背景技术Background technique

目前，在背光照明当中，为了均匀光线，通常会搭配扩散透镜使用，使光源发出的光线能以较大角度出射，从而达到大面积照明的效果。然而，在实际使用中，光源发出的光线经过透镜的扩散之后，由于光线在光源的光轴附近比较集中，有时并不能完全消除中央亮点的现象，不利于背光照明。At present, in backlighting, in order to uniform the light, it is usually used with a diffuser lens, so that the light emitted by the light source can exit at a larger angle, so as to achieve the effect of lighting a large area. However, in actual use, after the light emitted by the light source is diffused by the lens, because the light is relatively concentrated near the optical axis of the light source, sometimes the phenomenon of the central bright spot cannot be completely eliminated, which is not conducive to backlighting.

直下式背光模块是在通过透镜将LED器件发出的光线扩散均匀地扩散在尽量大的范围内，并通过这些光斑的相互交叠在被照面上形成均匀亮度出射。现有技术中，一种方式是通过折射的方式将光线扩散，或者通过将光线压缩在透镜侧面出射的形式并凭借反射纸的作用，将光线在很小的混光距离的情况下分布在较大的范围。The direct-type backlight module diffuses the light emitted by the LED device evenly in as large a range as possible through the lens, and forms uniform brightness output on the illuminated surface through the overlapping of these light spots. In the prior art, one way is to diffuse the light through refraction, or compress the light to emerge from the side of the lens, and rely on the function of reflective paper to distribute the light in a relatively small mixing distance. large range.

然而，已经有很多实际应用发现，当混光距离和LED器件间距的比值小于1:3的情况下，容易在被照明面上出现局部色空间分布不均匀的情况，通常是偏黄或偏蓝的色斑。通常情况下，在其他照明应用中，可以通过调节表面微结构来进行混光，也可以通过将出光面进行磨砂处理来实现混光。然而，由于直下式背光的混光距离很短而器件间距很大，需要在一个很大出射角范围内形成均匀照明，光学曲面的冗余度很低；如果是通过磨砂的方式，会破坏原有的光学面对光线的控制，使得光斑严重缩小；而通过微结构的方式在很短混光距离的情况下会形成近场效应，将微结构的形态“成像”在很近的接受屏上面，使得光斑斑斑点点，无法形成均匀亮度分布的照明效果。However, many practical applications have found that when the ratio of the light mixing distance to the LED device spacing is less than 1:3, it is easy to have uneven local color space distribution on the illuminated surface, usually yellowish or bluish of stains. Usually, in other lighting applications, light mixing can be achieved by adjusting the surface microstructure, or by frosting the light-emitting surface. However, due to the short light mixing distance of the direct-lit backlight and the large device spacing, it is necessary to form uniform illumination within a large range of exit angles, and the redundancy of the optical surface is very low; if it is frosted, it will destroy the original Some optical surfaces control the light so that the spot is severely reduced; and the near-field effect will be formed in the case of a very short light mixing distance by means of microstructures, and the shape of the microstructures will be "imaged" on a very close receiving screen. , so that the light spots are spotty, and it is impossible to form a lighting effect with uniform brightness distribution.

发明内容Contents of the invention

为解决现有技术的缺点和不足，本发明的首要目的在于提供一种具有非平滑曲线的直下式背光透镜。In order to solve the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a direct backlight lens with non-smooth curves.

本发明的方案为：一种具有非平滑曲线的直下式背光透镜，该透镜为旋转对称体，该透镜包括底面、入射面和出射面，光线自入射面射入透镜内，自出射面射出透明外；该旋转对称体的对称轴为光轴Z，穿过Z轴的截面沿Z轴的一侧与入射面的相交线为入射曲线C1，与出射面的相交线为出射曲线C2；以Z轴为Y轴建立直角坐标系，X轴位于截面上，则C1和C2中至少有一条曲线是按以下方式生成：The solution of the present invention is: a direct-type backlight lens with non-smooth curve, the lens is a rotationally symmetrical body, the lens includes a bottom surface, an incident surface and an exit surface, light enters the lens from the incident surface, and exits transparently from the exit surface Outside; the axis of symmetry of the rotationally symmetric body is the optical axis Z, the intersection line between the side of the Z axis and the incident surface along the Z axis is the incident curve C1, and the intersection line with the exit surface is the exit curve C2; The axis is the Y axis to establish a rectangular coordinate system, and the X axis is located on the section, then at least one of the curves in C1 and C2 is generated in the following way:

1)给定一平滑曲线C,该曲线C满足函数y＝C(x)，且其二阶导数为连续函数；1) Given a smooth curve C, the curve C satisfies the function y=C(x), and its second derivative is a continuous function;

2)在曲线C上等间隔取N个点，这些点的坐标为：2) Take N points at equal intervals on the curve C, and the coordinates of these points are:

y_i＝C(x_i)，(i＝1,2,…，N)，y _i =C(x _i ), (i=1,2,...,N),

其中x＝0时的点为第一个点，最后一个点为第N个点；The point when x=0 is the first point, and the last point is the Nth point;

3)将第奇数个点向上移动一个偏移量du，这些奇数点的坐标为：3) Move the odd-numbered points up by an offset du, and the coordinates of these odd-numbered points are:

y_{i_1}＝C(x)+du₁；y _{i_1} = C(x) + du ₁ ;

将第偶数个点向下移动相同的偏移量du，这些偶数点的坐标为：Move the even-numbered points down by the same offset du, and the coordinates of these even-numbered points are:

y_{i_2}＝C(x)-du₂；y _{i_2} = C(x) - du ₂ ;

经过位移的这些点的新坐标函数为y_i＝Cj(x)，其中y_i为第i个点的纵坐标；The new coordinate function of these points through displacement is y _i =Cj (x), wherein y _i is the ordinate of the i-th point;

4)用平滑连接方式逐段连接各点，形成新曲线y＝Cj(x)，即C1或/和C2。4) Connect each point segment by segment in a smooth connection manner to form a new curve y=Cj(x), ie C1 or/and C2.

优先的，所述步骤4)中，一种平滑连接的方式为，任意一个点的前段连接的曲线导数与后段连接的曲线导数相等。Preferably, in the step 4), a smooth connection method is that the curve derivative of the previous connection at any point is equal to the curve derivative of the subsequent connection.

优先的，所述曲线y＝Cj(x)的二阶导数在xi处不连续。Preferably, the second derivative of the curve y=Cj(x) Discontinuous at xi.

优先的，当C1为y＝Cj(x)时，C1上任意点与坐标原点的直线，与Y轴的夹角为α1，与原点的距离为R1，则，在α1＜π/3的范围内，R1随α1单调递减。Preferentially, when C1 is y=Cj(x), the angle between any point on C1 and the origin of the coordinates is α1, and the distance from the origin is R1. Then, in the range of α1<π/3 Inside, R1 decreases monotonically with α1.

优先的，当C2为y＝Cj(x)时，C2上任意点与坐标原点的直线，与Y轴的夹角为α2，与原点的距离为R2，则，在α2＜π/3的范围内，R2随α2单调递减。Preferentially, when C2 is y=Cj(x), the angle between any point on C2 and the origin of the coordinates is α2, and the distance from the origin is R2. Then, in the range of α2<π/3 Inside, R2 decreases monotonically with α2.

优先的，若透镜折射率为n，则相对于α2的增量Δα2的R2的增量ΔR₂，有如下关系：Preferably, if the refractive index of the lens is n, the increment ΔR ₂ of R2 relative to the increment Δα2 of α2 has the following relationship:

优先的，所述步骤4)中，所述平滑连接方式，为余弦拟合连接、多项式拟合连接或B-spline拟合连接。Preferably, in the step 4), the smooth connection method is cosine fitting connection, polynomial fitting connection or B-spline fitting connection.

优先的，du₁和du₂的绝对值与C2最后一个点的横坐标x_N的比值，均不大于0.001。Preferably, the ratio of the absolute value of du ₁ and du ₂ to the abscissa x _N of the last point of C2 is not greater than 0.001.

优先的，du₁＝du₂＞0。Preferentially, du ₁ =du ₂ >0.

优先的，du₁＝du₂＜0。Preferably, du ₁ =du ₂ <0.

优选的，N大于10。Preferably, N is greater than 10.

本发明的原理为：Principle of the present invention is:

图1a和图1b解释了直下式背光透镜形成色空间分布不一致的原因，图中方形部分为蓝光LED芯片，圆形部分为黄色荧光粉：由于白光LED由芯片和荧光粉组成，在现有技术中，大多采用3030或3528或2835等圆形发光面的封装形态进行封装，蓝光的等效发光面是LED 芯片的发光面；而荧光粉涂层面积是一大于芯片发光面的圆形发光面。Figure 1a and Figure 1b explain the reasons for the inconsistency of the color space distribution formed by the direct-type backlight lens. The square part in the figure is the blue LED chip, and the circular part is the yellow phosphor. Among them, most of them are packaged in the packaging form of 3030 or 3528 or 2835 with a circular light-emitting surface. The equivalent light-emitting surface of blue light is the light-emitting surface of the LED chip; and the phosphor coating area is a circular light-emitting surface that is larger than the light-emitting surface of the chip. .

如图2a和图2b，1mm发光面和一个2.5mm发光面的朗伯发光体经过同一个扩散性光学系统后在被照面上的照度分布图，可以看到，这两个照度分布是明显不同的，这就是说明这两个光斑在叠加的时候，一定会出现有的地方偏蓝有的地方偏黄的问题。As shown in Figure 2a and Figure 2b, the illuminance distribution diagrams of a Lambertian illuminant with a 1mm light-emitting surface and a 2.5mm light-emitting surface on the illuminated surface after passing through the same diffusive optical system, it can be seen that the two illuminance distributions are obviously different Yes, this means that when these two light spots are superimposed, there will definitely be a problem that some places are blue and some places are yellowish.

如图3a和图3b，同为2.5mm圆形发光面光强分布不同的两种光源经过同一个扩散性光学系统后在被照面上的照度分布图；其中一种光强分布是LED器件中黄光的分布，另一种是LED器件中蓝光部分的光强分布。我们发现，两个照度分布图差异较小。由此可见，相对于蓝光和黄光光强分布的不同，LED芯片和发光面的尺度差异才是造成被照面色空间分布不均匀的主要原因。As shown in Figure 3a and Figure 3b, the illuminance distribution diagrams of two light sources with different light intensity distributions on the same 2.5mm circular light-emitting surface pass through the same diffusive optical system on the illuminated surface; one of the light intensity distributions is the LED device. The distribution of yellow light, the other is the light intensity distribution of the blue part of the LED device. We found that the difference between the two illuminance profiles is small. It can be seen that, compared with the difference in the intensity distribution of blue light and yellow light, the scale difference between the LED chip and the light-emitting surface is the main reason for the uneven distribution of the illuminated surface color space.

本发明的主要原理在于，首先设计和优化一个能够实现均匀照明分布的光斑的透镜内曲面和外曲面。内曲面和外曲面是平滑的，其二阶导数是连续的。对于屏幕上的某一个位置，黄光和蓝光形成光束所覆盖的透镜出光面的范围是不同的，在某些位置有较大差别。通过本发明的技术方案，将外曲面在原有曲线的斜率分布上进行震荡，可以改变原有黄光和蓝光形成的光束覆盖范围，其特征在于，蓝光的范围会较为明显的向两端扩大；而黄光(大面积光源)的范围也会扩大，但扩大幅度不及小光源。原理是，通过震荡的结构形成了凸凹相间的微结构，这种微结构通过对黄光和蓝光成二次像，再从二次像位置发射。从光路上看，重新发射的光线由于成像位置远，黄光和蓝光的覆盖范围就会变小。最终这样的结果是，在原有透镜轮廓线斜率值周期性调制的光学曲面，可以降低光束覆盖范围对于发光光源尺寸的敏感性，从而改善颜色空间分布。The main principle of the present invention is to firstly design and optimize an inner curved surface and an outer curved surface of a lens capable of achieving a light spot with uniform illumination distribution. The inner and outer surfaces are smooth and their second derivatives are continuous. For a certain position on the screen, the scope of the lens light-emitting surface covered by the beams formed by the yellow light and the blue light is different, and there is a big difference in some positions. Through the technical solution of the present invention, the outer curved surface is oscillated on the slope distribution of the original curve, which can change the beam coverage formed by the original yellow light and blue light. It is characterized in that the range of blue light will obviously expand to both ends; The range of yellow light (large-area light source) will also expand, but the expansion rate is not as good as that of small light sources. The principle is that a convex-concave microstructure is formed through the oscillating structure. This microstructure forms a secondary image of yellow light and blue light, and then emits from the secondary image position. From the perspective of the optical path, the coverage of yellow light and blue light will become smaller due to the far imaging position of the re-emitted light. The final result of this is that the optical curved surface periodically modulates the slope value of the original lens contour line, which can reduce the sensitivity of the beam coverage to the size of the light source, thereby improving the color space distribution.

在原连续曲线(母线)的基础上，通过周期性地调整曲面每点斜率差值，可以实现上述功能；同时，在已经能够实现较大光斑的情况下使用这种曲面斜率调制，且保证这种斜率的调整足够微小，可以避免光斑尺寸、大小和均匀性不会有太大变化，且能够很好地实现局部色斑的改善。图4a和图4b分别为改善前后的照度分布图；图5a和图5b分别为改善前后的色差分布图。从二者的比较可以看出，本发明的方案降低了原有图4a的照度分布的“亮环”即照度突变的情况下，同时也获得了更加均匀的色差分布。图4a为使用平滑曲线的照度分布，图4b为使用本发明的照度分布，后者的光斑火毒更均匀，环状的结构更少。图5a为使用平滑曲线的色差分布，图5b为使用本发明的色差分布，后者的色均匀性也有所改善。On the basis of the original continuous curve (bus bar), the above functions can be realized by periodically adjusting the slope difference of each point on the surface; at the same time, the slope modulation of this surface can be used when a larger spot can be achieved, and this The adjustment of the slope is small enough to avoid large changes in the spot size, size, and uniformity, and to achieve a good improvement in local color spots. Figure 4a and Figure 4b are the illuminance distribution diagrams before and after improvement; Figure 5a and Figure 5b are the color difference distribution diagrams before and after improvement respectively. From the comparison of the two, it can be seen that the scheme of the present invention reduces the "bright ring" of the original illumination distribution in Figure 4a, that is, the sudden change in illumination, and at the same time obtains a more uniform color difference distribution. Fig. 4a shows the illuminance distribution using a smooth curve, and Fig. 4b shows the illuminance distribution using the present invention, the latter has more uniform flare and less ring-like structures. Figure 5a shows the color difference distribution using the smooth curve, and Figure 5b shows the color difference distribution using the present invention, the color uniformity of the latter is also improved.

附图说明Description of drawings

图1a为现有技术中蓝光LED芯片和黄色荧光粉形成的白光器件组合的仰视图Figure 1a is a bottom view of a combination of white light devices formed by blue LED chips and yellow phosphor powder in the prior art

图1b为图1a的侧视光路图Figure 1b is a side view optical path diagram of Figure 1a

图2a为1mm尺寸光源经过透镜后形成的照度分布图Figure 2a is the illuminance distribution diagram formed by a 1mm light source passing through the lens

图2b为2.5mm尺寸光源经过透镜后形成的照度分布图Figure 2b is the illuminance distribution diagram formed by the 2.5mm light source passing through the lens

图3a为2.5mm尺寸光源中的黄光照度分布图Figure 3a is the yellow light illuminance distribution diagram in the 2.5mm size light source

图3b为2.5mm尺寸光源中的蓝光照度分布图Figure 3b is the blue light illuminance distribution diagram in the 2.5mm size light source

图4a为现有技术透镜的照度分布图Fig. 4a is the illuminance distribution diagram of prior art lens

图4b为本发明透镜的照度分布图Fig. 4b is the illuminance distribution diagram of the lens of the present invention

图5a为现有技术透镜的色差分布图Fig. 5a is the chromatic aberration distribution diagram of prior art lens

图5b为本发明透镜的色差分布图Figure 5b is a chromatic aberration distribution diagram of the lens of the present invention

图6为本发明透镜的截面曲线图Fig. 6 is the sectional graph of lens of the present invention

具体实施方式Detailed ways

下面结合附图对本发明的具体实施方式做进一步说明：The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

如图6所示，本实施例一种具有非平滑曲线的直下式背光透镜，该透镜为旋转对称体，该透镜包括底面、入射面和出射面，光线自入射面射入透镜内，自出射面射出透明外；该旋转对称体的对称轴为光轴Z，穿过Z轴的截面沿Z轴的一侧与入射面的相交线为入射曲线C1，与出射面的相交线为出射曲线C2；以Z轴为Y轴建立直角坐标系，X轴位于截面上，则C1和C2中至少有一条曲线是按以下方式生成：As shown in Figure 6, the present embodiment is a direct-type backlight lens with a non-smooth curve. The lens is a rotationally symmetrical body. The lens includes a bottom surface, an incident surface and an exit surface. The surface is transparent; the symmetry axis of the rotationally symmetric body is the optical axis Z, the intersection line of the cross section passing through the Z axis along the side of the Z axis and the incident surface is the incident curve C1, and the intersection line with the exit surface is the exit curve C2 ; Establish a Cartesian coordinate system with the Z axis as the Y axis, and the X axis is located on the section, then at least one of the curves in C1 and C2 is generated in the following way:

1)给定一平滑曲线C,该曲线C满足函数y＝C(x)，且其二阶导数为连续函数；1) Given a smooth curve C, the curve C satisfies the function y=C(x), and its second derivative is a continuous function;

2)在曲线C上等间隔取N个点，这些点的坐标为：2) Take N points at equal intervals on the curve C, and the coordinates of these points are:

y_i＝C(x_i)，(i＝1,2,…，N)，y _i =C(x _i ), (i=1,2,...,N),

其中x＝0时的点为第一个点，最后一个点为第N个点；The point when x=0 is the first point, and the last point is the Nth point;

3)将第奇数个点向上移动一个偏移量du，这些奇数点的坐标为：3) Move the odd-numbered points up by an offset du, and the coordinates of these odd-numbered points are:

y_{i_1}＝C(x)+du₁；y _{i_1} = C(x) + du ₁ ;

将第偶数个点向下移动相同的偏移量du，这些偶数点的坐标为：Move the even-numbered points down by the same offset du, and the coordinates of these even-numbered points are:

y_{i_2}＝C(x)-du₂；y _{i_2} = C(x) - du ₂ ;

经过位移的这些点的新坐标函数为y_i＝Cj(x)，其中y_i为第i个点的纵坐标；The new coordinate function of these points through displacement is y _i =Cj (x), wherein y _i is the ordinate of the i-th point;

4)用平滑连接方式逐段连接各点，形成新曲线y＝Cj(x)，即C1或/和C2。4) Connect each point segment by segment in a smooth connection manner to form a new curve y=Cj(x), ie C1 or/and C2.

透镜的曲线如图6所示，深黑色曲线为原平滑曲线，相对浅灰色的曲线为改进后的透镜曲线；原深黑色平滑曲线被多个点分割为若干段，改进后的相对浅灰色曲线绕于深黑色线段之间。The curve of the lens is shown in Figure 6. The dark black curve is the original smooth curve, and the relatively light gray curve is the improved lens curve; the original dark black smooth curve is divided into several segments by multiple points, and the improved relatively light gray curve Wrapped between dark black line segments.

所述步骤4)中，一种平滑连接的方式为，任意一个点的前段连接的曲线导数与后段连接的曲线导数相等。In the step 4), a smooth connection method is that the curve derivative of the previous connection at any point is equal to the curve derivative of the rear connection.

所述曲线y＝Cj(x)的二阶导数在xi处不连续。The second derivative of the curve y=Cj(x) Discontinuous at xi.

当C1为y＝Cj(x)时，C1上任意点与坐标原点的直线，与Y轴的夹角为α1，与原点的距离为R1，则，在α1＜π/3的范围内，R1随α1单调递减。When C1 is y=Cj(x), the angle between any point on C1 and the origin of the coordinates is α1, and the distance from the origin is R1. In the range of α1<π/3, R1 Decreases monotonically with α1.

当C2为y＝Cj(x)时，C2上任意点与坐标原点的直线，与Y轴的夹角为α2，与原点的距离为R2，则，在α2＜π/3的范围内，R2随α2单调递减。When C2 is y=Cj(x), the angle between any point on C2 and the origin of the coordinates is α2, and the distance from the origin is R2. In the range of α2<π/3, R2 Decreases monotonically with α2.

若透镜折射率为n，则相对于α2的增量Δα2的R2的增量ΔR₂，有如下关系：If the refractive index of the lens is n, the increment ΔR ₂ of R2 relative to the increment Δα2 of α2 has the following relationship:

所述步骤4)中，所述平滑连接方式，为余弦拟合连接、多项式拟合连接或B-spline拟合连接。(B-spline，即B-样条曲线，是现有数学函数的一种。)In the step 4), the smooth connection method is cosine fitting connection, polynomial fitting connection or B-spline fitting connection. (B-spline, or B-spline curve, is a type of existing mathematical function.)

du₁和du₂的绝对值与C2最后一个点的横坐标x_N的比值，均不大于0.001。The ratio of the absolute value of du ₁ and du ₂ to the abscissa x _N of the last point of C2 is not greater than 0.001.

du₁＝du₂＞0。du ₁ =du ₂ >0.

N大于10。N is greater than 10.

本实施例的原理为：The principle of this embodiment is:

图1a和图1b解释了直下式背光透镜形成色空间分布不一致的原因，图中方形部分为蓝光LED芯片，圆形部分为黄色荧光粉：由于白光LED由芯片和荧光粉组成，在现有技术中，大多采用3030或3528或2835等圆形发光面的封装形态进行封装，蓝光的等效发光面是LED 芯片的发光面；而荧光粉涂层面积是一大于芯片发光面的圆形发光面。Figure 1a and Figure 1b explain the reasons for the inconsistency of the color space distribution formed by the direct-type backlight lens. The square part in the figure is the blue LED chip, and the circular part is the yellow phosphor. Among them, most of them are packaged in the packaging form of 3030 or 3528 or 2835 with a circular light-emitting surface. The equivalent light-emitting surface of blue light is the light-emitting surface of the LED chip; and the phosphor coating area is a circular light-emitting surface that is larger than the light-emitting surface of the chip. .

如图2a和图2b，1mm发光面和一个2.5mm发光面的朗伯发光体经过同一个扩散性光学系统后在被照面上的照度分布图，可以看到，这两个照度分布是明显不同的，这就是说明这两个光斑在叠加的时候，一定会出现有的地方偏蓝有的地方偏黄的问题。As shown in Figure 2a and Figure 2b, the illuminance distribution diagrams of a Lambertian illuminant with a 1mm light-emitting surface and a 2.5mm light-emitting surface on the illuminated surface after passing through the same diffusive optical system, it can be seen that the two illuminance distributions are obviously different Yes, this means that when these two light spots are superimposed, there will definitely be a problem that some places are blue and some places are yellowish.

如图3a和图3b，同为2.5mm圆形发光面光强分布不同的两种光源经过同一个扩散性光学系统后在被照面上的照度分布图；其中一种光强分布是LED器件中黄光的分布，另一种是LED器件中蓝光部分的光强分布。我们发现，两个照度分布图差异较小。由此可见，相对于蓝光和黄光光强分布的不同，LED芯片和发光面的尺度差异才是造成被照面色空间分布不均匀的主要原因。As shown in Figure 3a and Figure 3b, the illuminance distribution diagrams of two light sources with different light intensity distributions on the same 2.5mm circular light-emitting surface pass through the same diffusive optical system on the illuminated surface; one of the light intensity distributions is the LED device. The distribution of yellow light, the other is the light intensity distribution of the blue part of the LED device. We found that the difference between the two illuminance profiles is small. It can be seen that, compared with the difference in the intensity distribution of blue light and yellow light, the scale difference between the LED chip and the light-emitting surface is the main reason for the uneven distribution of the illuminated surface color space.

本发明的主要原理在于，首先设计和优化一个能够实现均匀照明分布的光斑的透镜内曲面和外曲面。内曲面和外曲面是平滑的，其二阶导数是连续的。对于屏幕上的某一个位置，黄光和蓝光形成光束所覆盖的透镜出光面的范围是不同的，在某些位置有较大差别。通过本发明的技术方案，将外曲面在原有曲线的斜率分布上进行震荡，可以改变原有黄光和蓝光形成的光束覆盖范围，其特征在于，蓝光的范围会较为明显的向两端扩大；而黄光(大面积光源)的范围也会扩大，但扩大幅度不及小光源。原理是，通过震荡的结构形成了凸凹相间的微结构，这种微结构通过对黄光和蓝光成二次像，再从二次像位置发射。从光路上看，重新发射的光线由于成像位置远，黄光和蓝光的覆盖范围就会变小。最终这样的结果是，在原有透镜轮廓线斜率值周期性调制的光学曲面，可以降低光束覆盖范围对于发光光源尺寸的敏感性，从而改善颜色空间分布。The main principle of the present invention is to firstly design and optimize an inner curved surface and an outer curved surface of a lens capable of achieving a light spot with uniform illumination distribution. The inner and outer surfaces are smooth and their second derivatives are continuous. For a certain position on the screen, the scope of the lens light-emitting surface covered by the beams formed by the yellow light and the blue light is different, and there is a big difference in some positions. Through the technical solution of the present invention, the outer curved surface is oscillated on the slope distribution of the original curve, which can change the beam coverage formed by the original yellow light and blue light. It is characterized in that the range of blue light will obviously expand to both ends; The range of yellow light (large-area light source) will also expand, but the expansion rate is not as good as that of small light sources. The principle is that a convex-concave microstructure is formed through the oscillating structure. This microstructure forms a secondary image of yellow light and blue light, and then emits from the secondary image position. From the perspective of the optical path, the coverage of yellow light and blue light will become smaller due to the far imaging position of the re-emitted light. The final result of this is that the optical curved surface periodically modulates the slope value of the original lens contour line, which can reduce the sensitivity of the beam coverage to the size of the light source, thereby improving the color space distribution.

在原连续曲线(母线)的基础上，通过周期性地调整曲面每点斜率差值，可以实现上述功能；同时，在已经能够实现较大光斑的情况下使用这种曲面斜率调制，且保证这种斜率的调整足够微小，可以避免光斑尺寸、大小和均匀性不会有太大变化，且能够很好地实现局部色斑的改善。图4a和图4b分别为改善前后的照度分布图；图5a和图5b分别为改善前后的色差分布图。从二者的比较可以看出，本发明的方案降低了原有图4a的照度分布的“亮环”即照度突变的情况下，同时也获得了更加均匀的色差分布。图4a为使用平滑曲线的照度分布，图4b为使用本发明的照度分布，后者的光斑火毒更均匀，环状的结构更少。图5a为使用平滑曲线的色差分布，图5b为使用本发明的色差分布，后者的色均匀性也有所改善。On the basis of the original continuous curve (bus bar), the above functions can be realized by periodically adjusting the slope difference of each point on the surface; at the same time, the slope modulation of this surface can be used when a larger spot can be achieved, and this The adjustment of the slope is small enough to avoid large changes in the spot size, size, and uniformity, and to achieve a good improvement in local color spots. Figure 4a and Figure 4b are the illuminance distribution diagrams before and after improvement; Figure 5a and Figure 5b are the color difference distribution diagrams before and after improvement respectively. From the comparison of the two, it can be seen that the scheme of the present invention reduces the "bright ring" of the original illumination distribution in Figure 4a, that is, the sudden change in illumination, and at the same time obtains a more uniform color difference distribution. Fig. 4a shows the illuminance distribution using a smooth curve, and Fig. 4b shows the illuminance distribution using the present invention, the latter has more uniform light spots and less annular structures. Figure 5a shows the color difference distribution using the smooth curve, and Figure 5b shows the color difference distribution using the present invention, the color uniformity of the latter is also improved.

根据上述说明书的揭示和教导，本发明所属领域的技术人员还可以对上述实施方式进行变更和修改。因此，本发明并不局限于上面揭示和描述的具体实施方式，对发明的一些修改和变更也应当落入本发明的权利要求的保护范围内。此外，尽管本说明书中使用了一些特定的术语，但这些术语只是为了方便说明，并不对本发明构成任何限制。According to the disclosure and teaching of the above-mentioned specification, those skilled in the art to which the present invention belongs can also make changes and modifications to the above-mentioned embodiment. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.