CN102829432A - Novel LED total reflection lens capable of realizing continuous zooming and design method of novel LED total reflection lens - Google Patents

Abstract

The invention discloses a novel LED total reflection lens capable of realizing continuous zooming and a design method of the novel LED total reflection lens, and belongs to the field of semiconductor illumination. The lens comprises a bottom containing cavity, a total reflection surface, a peripheral plane and a central transmission surface, the total reflection surface and the bottom containing cavity are connected with the peripheral plane, the peripheral plane is connected with the central transmission surface, the bottom containing cavity, the total reflection surface, the peripheral plane and the central transmission surface are symmetric around an optical axis, and both the total reflection surface and the central transmission surface are free-form surfaces. The novel LED total reflection lens realizes continuous zooming by a single total reflection lens, and is convenient to mount and adjust, and a system is small in size and. By the design method, light energy is distributed in a free-form surface manner, so that light energy utilization rate of the system and illuminance uniformity degree of a target surface are increased.

Description

A kind of New LED total-reflection type lens and method for designing that realizes continuous vari-focus

Technical field

The invention belongs to field of semiconductor illumination, relate to a kind of New LED total-reflection type lens and method for designing that realizes continuous vari-focus.

Background technology

Nowadays, LED is long owing to its life-span, and numerous advantages such as low energy consumption have obtained in various fields using widely, like road lighting, and LED projector and room lighting or the like.In many application scenarios, the angle of visual field of illuminated target face and the distance of light source and light beam is not changeless, as is applied to the infrared illumination equipment of night monitoring system; Requirement can change the angle of visual field and the energy density distribution of self according to the zooming range of thermal camera; Make its range of exposures cover whole guarded region,, can cause the luminous energy waste if the angle of visual field of infrared lamp is excessive; Otherwise then can produce the flashlight effect, influence illuminating effect.Therefore, the LED lamp optical system that needs the design continuous vari-focus.

The lamp optical system of traditional realization continuous vari-focus adopts the multi-disc form of lens to carry out luminous intensity distribution more, some problem below this form exists.At first, this structure can't be collected the wide-angle light beam, has caused the waste of luminous energy.The second, because the lens number often more than 1, causes system bulk bigger.At last, the conventional lenses structure Design free degree is lower, to a certain or structure that the design of two kinds of patterns obtains only under this pattern effect better, depart from its beam uniformity of back and then obviously descend.

Summary of the invention

In order to solve the problem that exists in the prior art; The invention provides a kind of New LED total-reflection type lens and method that realizes continuous vari-focus; On the basis of traditional total-reflection type lens; To the demands of different of light distribution, design its transmission plane and fully reflecting surface according to collimation pattern and divergent mode respectively.

The technical scheme that technical solution problem of the present invention is adopted is following:

A kind of New LED total-reflection type lens of realizing continuous vari-focus; These lens comprise: bottom cavity volume, fully reflecting surface, peripheral planar and central homology face; Fully reflecting surface links to each other with peripheral planar with the bottom cavity volume; Peripheral planar links to each other with the central homology face, and bottom cavity volume, fully reflecting surface, peripheral planar and central homology face are with symmetrical, and fully reflecting surface and central homology face are free form surface.

Based on a kind of method for designing that realizes the New LED total-reflection type lens of continuous vari-focus, this method comprises the steps:

Step 1: according to the distance of light source led and central homology face and light through the central homology face after the collimation outgoing, the face structure of computer center's transmission plane;

Step 2: establishing LED is desirable lambert's body; Try to achieve normalized light distribution and corresponding accumulation light flux distribution; Incident accumulation luminous flux is by forming through the luminous flux of central homology face with through the luminous flux of fully reflecting surface outgoing; Make LED move specific range,, find the solution the critical value of central homology face and angle that fully reflecting surface distributes based on the distance of LED and bottom cavity volume and the half width of bottom cavity volume along optical axis direction;

Step 3: according to realizing that the far field uniform light distribution of target face illumination obtains desirable outgoing accumulation light flux distribution; Obtained by desirable outgoing Energy distribution form, outgoing accumulation luminous flux equals incident accumulation luminous flux, tries to achieve incident ray and the corresponding relation of emergent ray on the fully reflecting surface, and then calculates the fully reflecting surface face structure;

Step 4: in the optics simulation software, simulate,, add modifying factor, obtain incident ray and the corresponding relation of emergent ray on the new fully reflecting surface according to analog result; Utilize the optics simulation software to simulate once more, meet the requirements, accomplish the method for designing of the New LED total-reflection type lens of realizing continuous vari-focus until analog result.

The invention has the beneficial effects as follows: a kind of New LED total-reflection type lens of continuous vari-focus of realizing of the present invention adopt single total-reflection type lens to realize continuous vari-focus, and system bulk is less, and is convenient to debug.This method for designing adopts the free form surface form to carry out the luminous energy distribution, has improved the uniformity of illuminance of the efficiency of light energy utilization and the target face of system.

Description of drawings

A kind of structure chart of realizing the New LED total-reflection type lens of continuous vari-focus of Fig. 1 the present invention.

The specific embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is explained further details.

As shown in Figure 1; A kind of New LED total-reflection type lens of realizing continuous vari-focus; These lens comprise: by bottom cavity volume, fully reflecting surface 3, peripheral planar 4 and central homology face 5 that plane 1 and plane 2 constitute, fully reflecting surface 3 links to each other with peripheral planar 4 with bottom cavity volume 1, and peripheral planar 4 links to each other with central homology face 5; Said bottom cavity volume, fully reflecting surface 3, peripheral planar 4 and central homology face 5 are with symmetrical, and fully reflecting surface 3 and transmission plane 5 are free form surface.Light source is P in the position ₁The time realize beam collimation through the central homology face, at P ₂The time beam divergence then.When LED is positioned at position P ₁The time,

Light after plane 1 and 5 transmissions of central homology face, be parallel to optical axis and penetrate.When LED is positioned at position P ₂The time,

Light 2 transmissions through the plane, fully reflecting surface 3 total reflections, at last after 4 outgoing of plane with 1 realize jointly that with the light of central homology face 5 transmissions far field target face illumination is even through the plane.

Based on a kind of method for designing that realizes the New LED total-reflection type lens of continuous vari-focus, this method comprises the steps:

Step 1: according to the position P of light source led ₁With the distance and the 5 back collimation outgoing of light process central homology face of central homology face 5, the face structure of computer center's transmission plane 5;

Step 2: establishing LED is desirable lambert's body, tries to achieve normalized incident intensity and distributes and corresponding accumulation light flux distribution, promptly

I(α)=cosα

${\mathrm{\φ}}_s\left(\mathrm{\α}\right)=\∫I\left(\mathrm{\α}\right)\mathrm{dw}=\mathrm{\π}{\sin }^2\mathrm{\α}$ ，

Wherein, α is the incidence angle of light source, and w is the solid angle of light source, and incident accumulation luminous flux is by the luminous flux φ through the central homology face _Refract(α) with through the luminous flux φ of fully reflecting surface outgoing _TIR(α) form.

In step 1, the face structure of central homology face draws.Therefore, can try to achieve LED and move the light distribution form of any distance transmissive part and the size of the angle of visual field according to snell law and law of conservation of energy along optical axis.According to desired maximum field of view angle value, can confirm the distance that LED moves along optical axis.

Make LED move l to P along optical axis direction ₂, establish LED at P ₁The distance on when point and plane 1 is h, through the distance h of bottom cavity volume and the half width d of bottom cavity volume, finds the solution the critical value of central homology face and angle that fully reflecting surface distributes

The luminous flux φ of central homology face _Refract(α) with through the luminous flux φ of fully reflecting surface outgoing _TIR(α)

Wherein, α _βExpression is corresponding to the incidence angle of angle of emergence β;

Step 3: according to realizing the uniform light distribution of far field target face illumination, integration obtains the desirable outgoing accumulation light flux distribution through fully reflecting surface 3 and transmission plane 5;

$I\left(\mathrm{\β}\right)=I_0/{\cos }^3\left(\mathrm{\β}\right)$

${\mathrm{\&phi;}}_t\left(\mathrm{\&beta;}\right)=I_0\mathrm{\&pi;}(1/{\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="HDA00001985590500011.png"\; state="\{\{state\}\}">cos</figure-callout>}}^2\mathrm{\&beta;}-1),\mathrm{\&beta;}\&Element;(0,{\mathrm{\&beta;}}_{\max })$

Normalization obtains I ₀=1/ (1/cos ²β _Max-1), obtained by desirable outgoing Energy distribution form, outgoing accumulation luminous flux equals incident accumulation luminous flux, promptly

${\mathrm{\&phi;}}_t\left(\mathrm{\&beta;}\right)={\mathrm{\&phi;}}_{\mathrm{refract}}\left(\mathrm{\&alpha;}\right)+{\mathrm{\&phi;}}_{\mathrm{TIR}}\left(\mathrm{\&alpha;}\right)$

Try to achieve incident ray and the corresponding relation of emergent ray on the fully reflecting surface;

Step 4: in the optics simulation software, simulate, owing in design process, LED is regarded as the ideal point light source, and the light-emitting area of actual LED has certain area, thereby must cause departing from of analog result and desired result.Therefore, need to introduce feedback procedure fully reflecting surface 3 is optimized, remember that the i time light distribution after feedback optimized is I _i(β), being accumulated light flux distribution behind the integration accordingly is φ _i(β).The target light intensity is distributed as I _t(β), accumulating light flux distribution accordingly is φ _t(β).Modifying factor ε _iBe expressed as the ratio of target distribution with the actual distribution of accumulation luminous flux:

${\mathrm{\&epsiv;}}_i={\mathrm{\&phi;}}_t\left(\mathrm{\&beta;}\right)/{\mathrm{\&phi;}}_0\left(\mathrm{\&beta;}\right)$

After utilizing modifying factor that the target accumulated luminous flux is revised, obtain the i+1 group corresponding relation of incident ray and emergent ray, be expressed as:

Obtain new lens arrangement thus, simulate with simulation software, repeat said process, meeting the requirements up to analog result gets final product.

In the present embodiment, light source adopts OSRAM SFH 4235 LED.P ₁With P ₂Apart from 1.5mm, the length overall 13.5mm of system, bore 26mm, these lens are realized 8 ° to 20 ° continuous vari-focus.

Claims (2)

1. New LED total-reflection type lens of realizing continuous vari-focus; It is characterized in that; These lens comprise: bottom cavity volume, fully reflecting surface, peripheral planar and central homology face, and fully reflecting surface links to each other with peripheral planar with the bottom cavity volume, and peripheral planar links to each other with the central homology face; Said bottom cavity volume, fully reflecting surface, peripheral planar and central homology face are with symmetrical, and fully reflecting surface and central homology face are free form surface.

2. based on the described a kind of method for designing that realizes the New LED total-reflection type lens of continuous vari-focus of claim 1, it is characterized in that this method comprises the steps:

Step 1: according to the distance of light source led and central homology face and light through the central homology face after the collimation outgoing, the face structure of computer center's transmission plane;

Step 2: establishing LED is desirable lambert's body; Try to achieve normalized light distribution and corresponding accumulation light flux distribution; Incident accumulation luminous flux is by forming through the luminous flux of central homology face with through the luminous flux of fully reflecting surface outgoing; Make LED move specific range,, find the solution the critical value of central homology face and angle that fully reflecting surface distributes based on the distance of LED and bottom cavity volume and the half width of bottom cavity volume along optical axis direction;

Step 3: according to realizing that the far field uniform light distribution of target face illumination obtains desirable outgoing accumulation light flux distribution; Obtained by desirable outgoing Energy distribution form, outgoing accumulation luminous flux equals incident accumulation luminous flux, tries to achieve incident ray and the corresponding relation of emergent ray on the fully reflecting surface, and then calculates the fully reflecting surface face structure;

Step 4: in the optics simulation software, simulate,, add modifying factor, obtain incident ray and the corresponding relation of emergent ray on the new fully reflecting surface according to analog result; Utilize the optics simulation software to simulate once more, meet the requirements, accomplish the method for designing of the New LED total-reflection type lens of realizing continuous vari-focus until analog result.

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