CN102420284A - Self-focusing lens and LED (light-emitting diode) packaging structure - Google Patents

Abstract

The invention discloses a self-focusing lens consisting of multiple layers of packaging adhesives with step-type changing refractive indexes, wherein the multiple layers of the packaging adhesives are vertically arranged in the shape of multiple rectangles on a vertical cross section; the first layer of the packaging adhesives is arranged in the middle; the second layer of the packaging adhesives, the third layer of the packaging adhesives, ......, and the ith layer of the adhesives are arranged at two sides of the first layer of the packaging adhesives in turn; and the refractive index of the ith layer of the packaging adhesives is ni, and the size relationship of the refractive indexes is n1>n2>......>ni-1>ni. According to the invention, the multiple layers of the packaging adhesives with different refractive indexes are adopted and are arranged according to step-refraction indexes to form the self-focusing lens, and the self-focusing lens is simple in structure, strong in practicability; and the height of the self-focusing lens is designed, and the light extraction efficiency of side light emission of an LED chip is increased, so that the light-emitting efficiency of an LED top surface is increased and the light-emitting effect is good. The invention also discloses an LED packaging structure which is provided with the self-focusing lens.

Description

GRIN Lens and LED encapsulating structure

Technical field

The present invention relates to a kind of LED encapsulation technology field, relate in particular to the LED encapsulating structure that a kind of raising is got the GRIN Lens of optical efficiency and is provided with this GRIN Lens.

Background technology

Led chip is luminous in the angle of 2 π; Because the refractive index ratio of led chip is higher, when the light of chip outgoing arrives air interface, can produces total reflection and cause its light extraction efficiency to reduce, therefore; Improve the luminous efficiency of LED, the optical efficiency of getting of its encapsulating structure is an emphasis.

Get optical efficiency in order to improve; As shown in Figure 1, in traditional packaged type, adopt individual layer silica gel or the epoxy resin of refractive index between LED tube core refractive index and air refraction to encapsulate covering LED tube core; But because the restriction of encapsulating material refractive index; On the interface of emergent medium and air, 1. full emission takes place greater than the wide-angle incident ray of the cirtical angle of total reflection in incidence angle, and light extraction efficiency is lower.

In order to improve the total reflection that causes because of above-mentioned refringence; Improve and get optical efficiency; The someone proposes to use method that multilayered medium material carries out the led chip encapsulation to reduce the refringence between " chip-packaging plastic-air " in recent years; But the height to this multilayer packaging plastic in the prior art does not stipulate clearly that randomness is very big, can not guarantee that all light can both shine in the external world.

Recently, the outer sealing that U.S.'s publication 11/708459 proposes to adopt graded index, improves and gets optical efficiency through self focusing effect control beam projecting angle as lens (like Fig. 2).Yet this mode implements the comparison difficulty: at first, the outer sealing of graded index is not also created, and manufacture difficulty is very high; Secondly; Though 2., through can shining the external world after the outer sealing control of graded index, 3. for the wide-angle emergent ray for the light of chip low-angle outgoing; Because the restriction of material refractive index; Have a big chunk light can not shine the external world, and 4. the outer sealing of this graded index have no control action for horizontal light.Therefore, be necessary to propose a kind ofly can to regulate light efficiency comprehensively, overcome intersection because of outer sealing and air and produce the light loss problem that total reflection causes, GRIN Lens structure with high light extraction efficiency and industrialization value.

Summary of the invention

In view of this, the LED device that the object of the present invention is to provide a kind of raising to get the GRIN Lens of optical efficiency and utilize these lens to make.

For solving the problems of the technologies described above, technical scheme of the present invention is:

A kind of GRIN Lens; Multilayer packaging plastic by the refractive index phase step type changes is formed; The multilayer packaging plastic is a plurality of rectangles and vertically arranges on vertical tangent plane; The 1st layer of packaging plastic is arranged on the middle part, and the 1st layer of packaging plastic both sides set gradually the 2nd layer of packaging plastic, the 3rd layer of packaging plastic ... .. and i layer packaging plastic, the refractive index of i layer packaging plastic is n _i, the refractive index magnitude relationship is n ₁＞n ₂＞...＞n _I-1＞n _i

Preferably, said multilayer packaging plastic is made up of a plurality of annular encapsulation glue-lines that with the led chip are the center of circle, radii size increase progressively gradually respectively.

Preferably; Said the 1st layer of packaging plastic top is folded successively from bottom to top to be provided with packaging plastic in the packaging plastic in the 1st layer, the 2nd layer ... packaging plastic in .. and the i layer; The refractive index of said interior packaging plastic is phase step type from bottom to top successively decreases, and wherein, the refractive index of packaging plastic is n ' in the i layer _i, the refractive index magnitude relationship is n ' ₁＞n ' ₂＞...＞n ' _I-1＞n ' _i, and the refractive index n of the 1st layer of packaging plastic ₁Greater than the refractive index n of packaging plastic in the 1st layer ' ₁

Preferably, the width of said interior packaging plastic equates with the width of the 1st layer of packaging plastic.

LED encapsulating structure of the present invention; Comprise substrate, be installed on led chip on the substrate, be formed on the substrate and coat the rectangle GRIN Lens of led chip; Said GRIN Lens is made up of the multilayer packaging plastic that the refractive index phase step type changes; The multilayer packaging plastic is a plurality of rectangles on vertical tangent plane vertically arranges, and the 1st layer of packaging plastic is arranged on the middle part, is coated on the led chip; The 1st layer of packaging plastic both sides set gradually the 2nd layer of packaging plastic, the 3rd layer of packaging plastic ... .. and i layer packaging plastic, the refractive index of i layer packaging plastic is n _i, the refractive index magnitude relationship is n ₁＞n ₂＞...＞n _I-1＞n _iSaid each layer height of multilayer packaging plastic

Wherein, h is the height of led chip, and m representes the maximum distance at 1 layer of packaging plastic of led chip bottom margin to the and the 2nd layer of packaging plastic interface.

Preferably, said multilayer packaging plastic is made up of a plurality of annular encapsulation glue-lines that with the led chip are the center of circle, radii size increase progressively gradually respectively.

Preferably; Said the 1st layer of packaging plastic top is folded successively from bottom to top to be provided with packaging plastic in the packaging plastic in the 1st layer, the 2nd layer ... packaging plastic in .. and the i layer; The refractive index of said interior packaging plastic is phase step type from bottom to top successively decreases, and wherein, the refractive index of packaging plastic is n ' in the i layer _i, the refractive index magnitude relationship is n ' ₁＞n ' ₂＞...＞n ' _I-1＞n ' _i, and the refractive index n of the 1st layer of packaging plastic ₁Greater than the refractive index n of packaging plastic in the 1st layer ' ₁

Preferably, the width of said interior packaging plastic equates with the width of the 1st layer of packaging plastic.

Preferably; Substrate is provided with reflector; Said led chip is arranged in the reflector; Reflector is interior by the 1st layer of packaging plastic complete filling of GRIN Lens; The height of said reflector wherein, b representes the beeline of led chip bottom margin perpendicular to reflector madial wall top place, c is the diagonal width of led chip; The inclination angle ω of the madial wall of said reflector and vertical direction is:

Preferably; Substrate is provided with reflector; Said led chip is arranged in the reflector; Reflector is interior by the 1st layer of packaging plastic complete filling of GRIN Lens; The height of said reflector

wherein, b representes the beeline of led chip bottom margin perpendicular to reflector madial wall top place, c is the diagonal width of led chip; The inclination angle ω of the madial wall of said reflector and vertical direction is:

Compared with prior art, GRIN Lens of the present invention and the LED encapsulating structure that is provided with this GRIN Lens have the following advantages:

The employing actual different packaging plastic of multilayer refractive index of applying is more arranged according to step index, and is simple in structure, practical to form GRIN Lens, can improve the optical efficiency of getting of led chip lateral emitting;

Further, establish the multilayer refractive index and be the interior packaging plastic that phase step type successively decreases from bottom to top through folded on the 1st layer of packaging plastic, improved the light extraction efficiency of led chip end face, bright dipping is effective.

Further; Confirm the height of GRIN Lens according to the maximum distance at the height of led chip and 1 layer of packaging plastic of led chip bottom margin to the and the 2nd layer of packaging plastic interface and the refractive index that covers the 1st layer of packaging plastic of led chip; The light that reaches adjusting leaves packing colloid fully; Can control lighting angle; Have the effect of control luminous intensity distribution, improve the effect of light extraction efficiency.Utilize the LED device of this GRIN Lens manufacturing can not need to add secondary lens, directly be used for low-angle illumination occasions such as shot-light, wall lamp.

Further; One reflector is set on substrate; Led chip is arranged in this reflector; The inclination angle of height and reflector madial wall and vertical plane through the accommodation reflex cup; Reach adjusting

light and can get into the multilayer packaging plastic through reflective cup reflects; And under the effect of multilayer packaging plastic not by total reflection leave packaging plastic, thereby can the light of led chip outgoing all be extracted into packaging plastic outside, light efficiency is greatly improved.

Description of drawings

Fig. 1 is traditional LED encapsulating structure cutaway view;

Fig. 2 is the LED encapsulating structure cutaway view of gradual index lens in the prior art;

Fig. 3 is the cutaway view that is provided with the LED encapsulating structure embodiment one of GRIN Lens of the present invention;

Fig. 4 is the vertical view that is provided with the LED encapsulating structure embodiment one of GRIN Lens of the present invention;

Fig. 5 is the cutaway view that is provided with the LED encapsulating structure embodiment two of GRIN Lens of the present invention.

Fig. 6 is the cutaway view that is provided with the LED encapsulating structure embodiment three of GRIN Lens of the present invention.

Embodiment

In order to make those skilled in the art understand technical scheme of the present invention better, the present invention is done further detailed description below in conjunction with accompanying drawing and specific embodiment.

Embodiment one

As shown in Figure 3, a kind of GRIN Lens that present embodiment provides and the LED encapsulating structure that utilizes this lens to make comprise substrate 101, are installed on led chip 102 on the substrate 101, are formed on the substrate 101 and coat the GRIN Lens 103 of led chip 102.The multilayer packaging plastic of GRIN Lens 103 is a plurality of rectangles and vertically arranges on vertical tangent plane; Wherein the 1st layer of packaging plastic is coated on the led chip 102; With the 1st layer of packaging plastic is the center, and other encapsulates glue-line---the 2nd layer of packaging plastic, the 3rd layer of packaging plastic ... .. i layer packaging plastic is arranged in order in the both sides of the 1st layer of packaging plastic; Refractive index with the 1st layer of packaging plastic is the center simultaneously, and the encapsulation glue-line refractive index of both sides is phase step type and changes, and the refractive index of establishing i layer packaging plastic is n _i, the refractive index magnitude relationship is n ₁＞n ₂＞...＞n _I-1＞n _i

A kind of GRIN Lens as shown in Figure 4, that present embodiment provides, the multilayer packaging plastic is made up of a plurality of annular encapsulation glue-lines that with the led chip are the center of circle, radii size increase progressively gradually respectively.

The height of GRIN Lens 103 and the functional relation of refractive index are derived as follows:

Among Fig. 3,5. be illustrated in the 1st layer of encapsulation medium, need do not pass through self focusing effect and the opticpath of an outgoing of GRIN Lens 103, α lightlike line for this reason gets into airborne maximum incident angle; 6. expression is through the opticpath of outgoing after the self focusing effect of GRIN Lens 103; M representes the maximum distance at 1 layer of packaging plastic of led chip 102 bottom margins to the and the 2nd layer of packaging plastic interface; H _LensThe height of expression GRIN Lens 103; The height of led chip 102 is h.

(1)

According to Snell's law and reflection law,, need to satisfy if 5. light shine the external world and total reflection does not take place from preparatory face

$\sin \mathrm{\&alpha;}<\frac{1}{n_1}---(1-1);$

Again,

Calculate by (1-1) with (1-2), draw

The height of GRIN Lens 103:

(2)

As can be seen from Figure 3: shine the external world will pass through the self focusing effect of GRIN Lens 103 greater than the light of α angle outgoing after, 6. this lightlike line belongs to, can know,

According to Snell's law, the deviation angular relationship of light from ground floor to a last Es-region propagations is:

${\mathrm{<figure-callout\; id="1"\; label="n"\; filenames="HDA0000104933580000011.png"\; state="\{\{state\}\}">n</figure-callout>}}_1\sin {\mathrm{\&theta;}}_1={\mathrm{<figure-callout\; id="2"\; label="n"\; filenames="HDA0000104933580000012.png"\; state="\{\{state\}\}">n</figure-callout>}}_2\sin {\mathrm{\&theta;}}_2=...=n_i\sin {\mathrm{\&theta;}}_i=n_i\cos {\mathrm{\&theta;}}_{\mathrm{out}}=n_i\sqrt{1-{\sin }^2{\mathrm{\&theta;}}_{\mathrm{out}}}---(1-5)$

And 6. light shine the external world and total reflection do not take place from preparatory face, needs to satisfy

$\sin {\mathrm{\&theta;}}_{\mathrm{out}}<\frac{1}{n_i}---(1-6);$

Calculate by (1-5) with (1-6), draw

The side angle of incidence of light ${\mathrm{\&theta;}}_1>\mathrm{Arcsin}\frac{\sqrt{n_i^2-1}}{n_1}---(1-7);$

Can know by (1-4) with (1-7); The LED device that utilizes GRIN Lens provided by the invention to make; Improved effectively scope chip light-emitting light get optical efficiency, improve the end face luminous efficiency.

In the present embodiment; During as

; The light of

can be through the 1st layer of packaging plastic by the total reflection outgoing, and the light of

can finally not left packing colloid by total reflection under the effect of multilayer packaging plastic.Therefore; The light that present embodiment can be regulated can not left packing colloid by total reflection, thereby reaches the purpose that improves light efficiency.

Present embodiment adopts actual, as the to have industrialization value multilayer step index material of more fitting to form GRIN Lens; According to the Si Nieer theorem; Derive the height of GRIN Lens and the functional relation of refractive index,, can confirm the height of GRIN Lens according to the refractive index of packaging plastic according to this functional relation; Also can select the refractive index of packaging plastic according to the height of GRIN Lens, can improve more effectively and get optical efficiency and end face light extraction efficiency.

Embodiment two

As shown in Figure 5, present embodiment and first embodiment difference are, in the present embodiment, a reflector 104 are set on substrate 101, place led chip 102 in the reflector 104.Wherein, scribble one deck high reflecting metal film on the inwall of reflector 104, and reflector 104 is interior by the 1st layer of packaging plastic complete filling of GRIN Lens 103.

Functional relation between the height of GRIN Lens 103, reflector 104 height, reflector 104 inclinations angle and the refractive index is derived as follows:

Among Fig. 5, represent respectively that 7. and 8. the high angle scattered light of led chip 102 outgoing is reflected the cup reflection after two opticpaths of left and right sides GRIN Lens effect outgoing; H _LensThe height of expression GRIN Lens 103; H _CupThe height of expression reflector 104; ω is the inclination angle of reflector 104 madial walls and vertical direction; The height of led chip 102 is h; M representes the maximum distance at 1 layer of packaging plastic of led chip bottom margin to the and the 2nd layer of packaging plastic interface; B representes the beeline of led chip bottom margin to reflector madial wall top place perpendicular, and at the bottom of the straight line AB vertical reflection cup cup, intersection point is B; The diagonal width of led chip 102 is c.

With embodiment one; If light shines end face and total reflection does not take place from the 1st layer of packaging plastic, need satisfy the height of GRIN Lens 103:

By geometrical relationship draws

and draw if make light after GRIN Lens control, can shine end face according to the side angle of incidence of light of embodiment one, need satisfy the height of reflector 104:

When ω was enough big, the high angle scattered light of led chip 102 outgoing was reflected cup reflection after left GRIN Lens effect outgoing, and 7. this lightlike line belongs to.According to geometrical relationship, the minimum incidence angle at the ground floor of left GRIN Lens 103 and second layer packaging plastic interface

And the side angle of incidence of light

according to embodiment one draws

The inclination angle of reflector 104

When ω was enough little, the high angle scattered light of led chip 102 outgoing was reflected cup reflection after right GRIN Lens effect outgoing, and 8. this lightlike line belongs to.According to geometrical relationship, the minimum incidence angle at the ground floor of right GRIN Lens 103 and second layer packaging plastic interface

In like manner draw,

Therefore, cup 104 reflects after GRIN Lens 103 effects shine end face when high angle scattered light is reflected, and the inclination angle ω of reflector 104 need satisfy:

Present embodiment adds the reflector that the inclination angle is

on the basis of embodiment one; And limit lens height for

and the reflector height reach this lightlike line of regulating

among the embodiment one for

and can get into the multilayer packaging plastic through reflective cup reflects, and under the effect of multilayer packaging plastic not by total reflection leave packaging plastic.Therefore, present embodiment can all be extracted into the light of chip outgoing the packaging plastic outside, to reach the purpose of effective raising light efficiency.

Embodiment three

As shown in Figure 6; The difference of present embodiment and embodiment two is; In the present embodiment, the 1st layer of packaging plastic top is folded successively from bottom to top is provided with packaging plastic in the packaging plastic in the 1st layer, the 2nd layer ... packaging plastic in .. and the i layer, said in the refractive index of packaging plastic be phase step type from bottom to top and successively decrease; Wherein, the refractive index of packaging plastic is n ' in the i layer _i, the refractive index magnitude relationship is n ' ₁＞n ' ₂＞n ' _I-1＞n ' _I-1＞n ' _i, and the refractive index n of the 1st layer of packaging plastic ₁Greater than the refractive index n of packaging plastic in the 1st layer ' ₁The width of interior packaging plastic equates with the width of the 1st layer of packaging plastic.

In the present embodiment; The light of

angular range of led chip emission; Be the interior packaging plastic effect that phase step type successively decreases from bottom to top and arrive the external world from the top outgoing of the 1st layer of packaging plastic and through the multilayer refractive index; Increase the optical transmission rate, improved the light extraction efficiency of led chip end face; The light of

angular range of led chip emission; The light that can regulate this angular range through the height qualification of multilayer packaging plastic can finally not left packing colloid by total reflection under the self focusing effect of multilayer packaging plastic, improve the light extraction efficiency of led chip side; The light of

angular range of led chip emission; Get into the multilayer packaging plastic through reflective cup reflects, and under the effect of multilayer packaging plastic not by total reflection leave packaging plastic.Therefore, the LED encapsulating structure of embodiment three can greatly improve the optical efficiency of getting of led chip.

More than the present invention has been carried out detailed introduction, use concrete example in the literary composition principle of the present invention and execution mode set forth, the explanation of above embodiment just is used for helping to understand method of the present invention and core concept thereof.Should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention, can also carry out some improvement and modification to the present invention, these improvement and modification also fall in the protection range of claim of the present invention.

Claims (10)

1. GRIN Lens; It is characterized in that; Multilayer packaging plastic by the refractive index phase step type changes is formed, and the multilayer packaging plastic is a plurality of rectangles on vertical tangent plane vertically arranges, and the 1st layer of packaging plastic is arranged on the middle part; The 1st layer of packaging plastic both sides set gradually the 2nd layer of packaging plastic, the 3rd layer of packaging plastic ... .. and i layer packaging plastic, the refractive index of i layer packaging plastic is n _i, the refractive index magnitude relationship is n ₁＞n ₂＞...＞n _I-1＞n _i

2. GRIN Lens as claimed in claim 1 is characterized in that, said multilayer packaging plastic is made up of a plurality of annular encapsulation glue-lines that with the led chip are the center of circle, radii size increase progressively gradually respectively.

3. according to claim 1 or claim 2 GRIN Lens; It is characterized in that; Said the 1st layer of packaging plastic top is folded successively from bottom to top to be provided with envelope in the packaging plastic in the 1st layer, the 2nd layer ... packaging plastic in .. and the i layer; The refractive index of said interior packaging plastic is phase step type from bottom to top successively decreases, and wherein, the refractive index of packaging plastic is n ' in the i layer _i, the refractive index magnitude relationship is n ' ₁＞n ' ₂＞...＞n ' _I-1＞n ' _i, and the refractive index n of the 1st layer of packaging plastic ₁Greater than the refractive index n of packaging plastic in the 1st layer ' ₁

4. GRIN Lens as claimed in claim 3 is characterized in that, the width of said interior packaging plastic equates with the width of the 1st layer of packaging plastic.

5. LED encapsulating structure; It is characterized in that; Comprise substrate, be installed on led chip on the substrate, be formed on the substrate and coat the rectangle GRIN Lens of led chip, said GRIN Lens is made up of the multilayer packaging plastic that the refractive index phase step type changes, and the multilayer packaging plastic is a plurality of rectangles and vertically arranges on vertical tangent plane; The 1st layer of packaging plastic is arranged on the middle part; Be coated on the led chip, the 1st layer of packaging plastic both sides set gradually the 2nd layer of packaging plastic, the 3rd layer of packaging plastic ... .. and i layer packaging plastic, the refractive index of i layer packaging plastic is n _i, the refractive index magnitude relationship is n ₁＞n ₂＞...＞n _I-1＞n _iSaid each layer height of multilayer packaging plastic Wherein, h is the height of led chip, and m representes the maximum distance at 1 layer of packaging plastic of led chip bottom margin to the and the 2nd layer of packaging plastic interface.

6. LED encapsulating structure as claimed in claim 5 is characterized in that, said multilayer packaging plastic is made up of a plurality of annular encapsulation glue-lines that with the led chip are the center of circle, radii size increase progressively gradually respectively.

7. like claim 5 or 6 described LED encapsulating structures; It is characterized in that; Said the 1st layer of packaging plastic top is folded successively from bottom to top to be provided with packaging plastic in the packaging plastic in the 1st layer, the 2nd layer ... packaging plastic in .. and the i layer; The refractive index of said interior packaging plastic is phase step type from bottom to top successively decreases, and wherein, the refractive index of packaging plastic is n ' in the i layer _i, the refractive index magnitude relationship is n ' ₁＞n ' ₂＞...＞n ' _I-1＞n ' _i, and the refractive index n of the 1st layer of packaging plastic ₁Greater than the refractive index n of packaging plastic in the 1st layer ' ₁

8. LED encapsulating structure as claimed in claim 7 is characterized in that, the width of said interior packaging plastic equates with the width of the 1st layer of packaging plastic.

9. like claim 5 or 6 described LED encapsulating structures; It is characterized in that; Substrate is provided with reflector; Said led chip is arranged in the reflector, and by the 1st layer of packaging plastic complete filling of GRIN Lens, the height of said reflector wherein in the reflector; B representes the beeline of led chip bottom margin to reflector madial wall top place perpendicular, and c is the diagonal width of led chip; The inclination angle ω of the madial wall of said reflector and vertical direction is:

10. LED encapsulating structure as claimed in claim 7; It is characterized in that; Substrate is provided with reflector; Said led chip is arranged in the reflector, and by the 1st layer of packaging plastic complete filling of GRIN Lens, the height of said reflector wherein in the reflector; B representes the beeline of led chip bottom margin to reflector madial wall top place perpendicular, and c is the diagonal width of led chip; The inclination angle ω of the madial wall of said reflector and vertical direction is:

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