CN101452922B - Light emitting unit - Google Patents

Abstract

The invention relates to a light-emitting unit, which comprises a substrate, at least one light-emitting diode chip, at least one lead and at least one sealing colloid. The LED chip is disposed on the substrate by an adhesive material. A first end of the wire is connected to the LED chip, a second end of the wire is connected to the substrate, the second end has a first distance from the center point of the LED chip, and the highest point of the wire has a second distance from the substrate. The packaging colloid covers at least part of the LED chip, and the total volume of the packaging colloid and the LED chip is smaller than the volume of a cylinder formed by a first distance and a second distance, wherein the first distance is the radius of the cylinder, the second distance is the height of the cylinder, and the connection surface of the LED chip and the substrate is positioned on the same horizontal plane as the second end of the lead.

Description

light unit

technical field

The invention relates to a light emitting unit, in particular to a light emitting unit with a closed space.

Background technique

Since the light emitting diode (Light Emitting Diode, LED) has the advantages of high brightness and power saving, as the technology of the light emitting diode gradually matures, its application fields are becoming more and more extensive, such as light source and backlight source.

Referring to FIG. 1 , a conventional light-emitting unit 1 includes a substrate 11 , a light-emitting diode chip 12 , an encapsulant 13 and a reflective housing (lamp house) 14 . Wherein, the LED chip 12 is disposed on the substrate 11 and is electrically connected to the substrate 11 by wire bonding. The encapsulant 13 is a light-transmitting material and is used to protect the LED chip 12 . The reflective housing 14 utilizes reflection to concentrate the light emitting direction of the light emitting diodes.

In the prior art, when the light-emitting diode chip 12 emits light, it will generate a large amount of heat energy, and the thermal expansion of the materials of the light-emitting diode chip 12, the cured encapsulant 13, the substrate 11, and the reflective shell 14 is not the same. The same, so it will cause the wire W sandwiched between the light emitting diode chip 12, the encapsulant 13, the substrate 11 and the reflective shell 14 to be deformed or broken by being squeezed or pulled, which may cause the light emitting diode chip 12 Failure to emit light will also cause defects in the light emitting unit 1 . Among them, the influence caused by the different degrees of thermal expansion is more serious especially in the light-emitting unit with a large-area encapsulant.

In addition, the existing technical framework cannot improve the heat dissipation problem of the LED. The PN junction with the highest temperature is still covered by a high-thickness encapsulant, so heat can only be conducted to the substrate through heat conduction.

Therefore, how to provide a light-emitting unit that can prevent the wires of the light-emitting diode chip from being broken due to the difference in thermal expansion between the casing, the encapsulant, the light-emitting diode chip and the substrate, and a light-emitting unit that can improve heat dissipation have become important. one of the subjects.

Contents of the invention

In view of the above-mentioned problems, the object of the present invention is to overcome the deficiencies and defects of the prior art, and propose a method that can avoid the breakage of the wires of the light-emitting diode chip due to the difference in thermal expansion of the material between the housing, the sealing body, the light-emitting diode chip and the substrate. light emitting unit.

To achieve the above purpose, the present invention provides a light emitting unit, which includes a substrate, at least one light emitting diode chip, at least one wire and at least one encapsulant. The LED chip is arranged on the substrate with an adhesive material. A first end of the wire is connected to the LED chip, a second end is connected to the substrate, the second end has a first distance from the center point of the LED chip, and the highest point of the wire has a second distance from the substrate. The encapsulant covers at least part of the LED chip, and the sum of the volumes of the encapsulant and the LED chip is smaller than the volume of a cylinder formed by the first distance and the second distance, wherein the first distance is the radius of the cylinder, and the second The distance is the height of the cylinder, and the connection surface between the LED chip and the substrate is located at the same level as the second end of the wire.

To achieve the above purpose, the present invention also provides a light emitting unit, which includes a substrate, at least one light emitting diode chip, at least one encapsulant, and at least one wire. The light-emitting diode chip is arranged on the substrate with an adhesive material, and the encapsulant covers at least a part of the area of the light-emitting diode chip. A first end of the wire is connected to the light-emitting diode chip, a second end is connected to the substrate and at least a part of the wire is exposed to the encapsulant, wherein the connection surface between the light-emitting diode chip and the substrate is located at the same level as the second end of the wire level.

Based on the above, the present invention has the following beneficial technical effects: because the volume thickness of a light-emitting unit according to the present invention is much smaller than that of the prior art, it can prevent the wires connected between the light-emitting diode chip and the substrate from being pulled or squeezed. Deformation or breakage occurs. In addition, after the thickness of the encapsulant is reduced, the heat dissipation path of the LED chip can not only dissipate heat through the lower substrate, but also directly dissipate heat through the upper side.

Description of drawings

Fig. 1 is a schematic diagram of an existing lighting unit;

Fig. 2A is a schematic diagram of a light-emitting unit according to the first embodiment of the present invention, and Fig. 2B is a cross-sectional view along the line A-A in Fig. 2A;

3A and 3B are schematic diagrams of changes in the light emitting unit of the first embodiment of the present invention;

Fig. 4A is a schematic diagram of a light-emitting unit according to a second embodiment of the present invention, and Fig. 4B is a cross-sectional view of the light-emitting unit along the line A-A in Fig. 4A;

FIG. 5A and FIG. 5B are schematic diagrams of a variation of the light emitting unit of the second embodiment of the present invention;

FIG. 6 is a schematic diagram of another variation of the light emitting unit according to the second embodiment of the present invention;

Fig. 7 is a schematic diagram of the changing state of the reflective layer of the present invention disposed on the substrate;

Fig. 8 is a schematic diagram of another variation of the light emitting unit according to the second embodiment of the present invention;

9A and 9B are schematic diagrams of a light emitting unit according to a third embodiment of the present invention;

FIG. 10 is a schematic diagram of another variation of the light emitting unit according to the third embodiment of the present invention;

FIG. 11 is a schematic diagram of another variation of the light emitting unit of the third embodiment of the present invention.

Explanation of symbols in the figure

1, 2, 3, 4, 5 lighting units

11, 22, 32, 42 substrates

12, 23, 33, 43, 53 LED chips

13, 25, 25A, 25B, 45, 55 sealants

14. L reflective housing

21, 31 light-transmitting shell

211, 411, 511 confined space

231 center point

24. W wire

241 first end

242 second end

26, 46 connection electrodes

37, 37A～37D, 47 reflective layer

371 opening

38, 48 fluorescent conversion layer

412, 413 housing components

51, 51A hollow shell

A-A, B-B straight line

C cylinder

D1 first distance

D2 second distance

H highest point

S lens structure

T phosphor tape

T1 adhesive layer

T2 fluorescent layer

Detailed ways

A light emitting unit according to the present invention will be described below with reference to related drawings, wherein the same components are denoted by the same reference numerals.

first embodiment

Please refer to FIG. 2A and FIG. 2B at the same time, wherein FIG. 2B is a cross-sectional view of the light emitting unit 2 along the line A-A in FIG. 2A . A light emitting unit 2 according to the first embodiment of the present invention includes a substrate 22 , at least one LED chip 23 , at least one wire 24 and at least one encapsulant 25 . In this embodiment, the two wires 24 are taken as an example for illustration. In addition, in this embodiment, the light emitting unit 2 further includes a light-transmitting casing 21 .

The transparent casing 21 may have a transparent portion and a non-transparent portion, that is, the transparent casing 21 may be partially transparent and partially opaque, and of course the transparent casing 21 may also be completely transparent. Wherein, the material of the light-transmitting part of the light-transmitting housing 21 is, for example, at least one of polymer material, glass or quartz, while the material of the non-transparent part is, for example, at least one of polymer material, ceramic or metal. one. In this embodiment, the light-transmitting shell 21 is illustrated by taking a transparent polymer material as an example, and the polymer material is selected from polystyrene (polystyrene, PS), polycarbonate (polycarbonate, PC), styrene- At least one of methyl methacrylate resin (methylstyrene, MS), polymethylmethacrylate (polymethylmethacrylate, PMMA) or acrylonitrile-butadiene-styrene (Acrylonitrile Butadiene Styrene, ABS). In addition, if the material of the light-transmitting housing 21 is metal, there is an opening on the light-emitting surface of the LED chip 23 , which is a light-transmitting portion for emitting light. Since the metal itself has the advantages of high reflectivity, good heat dissipation effect and easy processing and molding, the application range of the light emitting unit 2 can be increased.

Furthermore, the light-transmitting shell 21 made of polymer material can also be doped with a plurality of scattering centers to increase the effect of light diffusion. Wherein, the scattering body is, for example, scattering particles or scattering bubbles, and the material of the scattering particles can be organic scattering particles or inorganic scattering particles having a refractive index different from that of the light-transmitting shell 21, such as aluminum oxide (Al ₂ O ₃ ), barium sulfate (BaSO ₄ ) or silicon dioxide (SiO ₂ ), etc.

The substrate 22 is, for example, a glass substrate, a resin substrate, a ceramic substrate or a metal substrate, and forms a closed space 211 with the transparent housing 21 . Wherein, the closed space 211 may be vacuum or filled with gas, such as nitrogen or inert gas. In addition, the closed space 211 can also be filled with a colloid or a fluid, wherein the colloid is, for example, a liquid colloid or an elastic colloid, and the fluid is, for example, an oily fluid, and the refractive index of the liquid colloid, elastic colloid or oily fluid is greater than 1.3. In addition, when the surface of the light-transmitting shell 21 is a curved surface, the refractive index of the liquid colloid, elastic colloid or oily fluid can be greater than or equal to the light-transmitting shell 21, which can cause the light-collecting function, making the light-transmitting shell The light emitting surface of 21 forms an effect similar to a convex lens.

The LED chip 23 is disposed on the substrate 22 with an adhesive material. The emission spectrum of the light emitting diode chip 23 is, for example, the visible light range and/or the ultraviolet light range. If the emission spectrum of the light emitting diode chip 23 is in the visible light range, the light emitting diode chip 23 can be selected from red light emitting diode chips, green light emitting diode chips A group formed by light emitting diode chips, blue light emitting diode chips and combinations thereof.

Please refer to FIG. 2B , a first end 241 of the wire 24 is connected to the LED chip 23 , and a second end 242 of the wire 24 is connected to the substrate 22 . There is a first distance D1 between the second end 242 of the wire 24 and the center point 231 of the LED chip 23 , and a second distance D2 between the highest point H of the wire 24 and the substrate 22 . Wherein, it should be noted that the center point 231 of the LED chip 23 refers to the geometric center point of the bonding surface of the LED chip 23 and the substrate 22 .

Please refer to FIG. 2A and FIG. 2B at the same time, the encapsulant 25 covers at least part of the LED chip 23, and the total volume of the encapsulant 25 and the LED chip 23 is smaller than a distance formed by the first distance D1 and the second distance D2. The volume of cylinder C, wherein the first distance D1 is the radius of cylinder C, and the second distance D2 is the height of cylinder C. In this embodiment, the encapsulant 25 completely covers the LED chip 23 and the wire 24 as an example for illustration. The encapsulant 25 can be a multilayer refractive index material structure, and its material property is that the refractive index of the material is arranged from large to small along with the distance from each LED chip 23 from near to far. Therefore, by virtue of the characteristics of the multi-layer refractive index material structure of the encapsulant 25 , the range of light emission from the LED chip 23 can be increased, thereby making the light emission of the light emitting unit 2 more uniform.

In addition, please refer to FIG. 3A , the encapsulant 25A can also be extended between the wire 24 and the substrate 22 . In addition, please refer to FIG. 3B , at least part of the wires 24 may also be exposed on the sealing body 25B.

Please refer to FIG. 2A again. In this embodiment, the light emitting unit 2 further includes at least two connection electrodes 26 . The connection electrodes 26 are electrically connected to the LED chips 23 , and the connection electrodes 26 can be disposed at one end of the substrate 22 , at both ends of the substrate 22 or at any position on the substrate 22 . Wherein, the connection electrode 26 is disposed outside the transparent housing 21 . In this embodiment, the connection electrode 26 is set at one end of the substrate 22 as an example.

As mentioned above, since the LED chip 23 is located in the airtight space 211 of the light-transmitting housing 21 , the light-transmitting housing 21 can protect the LED chip 23 from external environmental factors such as moisture or dust. Therefore, the encapsulant 25 of the light emitting unit 2 in this embodiment only serves to improve the light extraction efficiency and the light output range of the LED chip 23 . Since the volume thickness of the encapsulant 25 is much smaller than that of the prior art encapsulant, the wire 24 connected between the LED chip 23 and the substrate 22 can be prevented from being deformed or broken due to being pulled or squeezed. In addition, after the thickness of the encapsulant 25 is reduced, the heat dissipation path of the light-emitting diode chip 23 can not only dissipate heat through the lower substrate 22, but also directly dissipate heat through the upper part, and if the airtight space 211 is filled with gas, liquid colloid, elastic colloid or oil The heat dissipation effect of the light-emitting diode chip 23 can be improved through its thermal convection effect.

second embodiment

Please refer to Figure 4A and Figure 4B at the same time, wherein Figure 4B is a cross-sectional view of the light emitting unit 3 along the line B-B in Figure 4A, the difference between the light emitting unit 3 of the second embodiment of the present invention and the first embodiment lies in: the light emitting unit 3 further includes a reflective portion and at least one fluorescent conversion layer 38 . Wherein, the reflective part can be a part of the light-transmitting housing 31 , or a reflective layer 37 can be added as described in this embodiment.

The reflective layer 37 is disposed on the outer surface of the light-transmitting housing 31 , and has at least one opening 371 , and the opening 371 corresponds to a light emitting surface of the LED chip 33 . The material of the reflective layer 37 is selected from one of the ultraviolet light band (200-400nm), visible blue light band (400-480nm) or full visible light band (400-780nm) in the reflection spectrum, and its reflectivity is at least greater than 50%. In addition, the reflective layer 37 can also be formed on the outer surface of the transparent housing 31 by coating or printing materials such as titanium dioxide (TiO ₂ ), barium sulfate (BaSO ₄ ) or aluminum oxide (Al ₂ O ₃ ), or The above-mentioned materials are added into the plastic material, and then the reflective layer 37 is formed by means of extrusion molding, injection molding and the like. Moreover, the reflective layer 37 can also be realized by a reflective film, a lens or a multi-layer coating material on the outer surface of the transparent housing 31 .

The fluorescent conversion layer 38 can be disposed on at least part of the outer surface and/or part of the inner surface of the transparent casing 31 or directly doped in the transparent casing 31 . In this embodiment, the fluorescent conversion layer 38 is disposed on the outer surface of the transparent casing 31 corresponding to the opening 371 . And the fluorescent conversion layer 38 is selected from at least one of a yellow fluorescent conversion layer, a red fluorescent conversion layer, a green fluorescent conversion layer or a blue fluorescent conversion layer.

The light emitting direction of the light emitting unit 3 can be concentrated through the arrangement of the reflective layer 37 , and the light emitted by the LED chip 33 can be mixed in the light-transmitting housing 31 before being emitted by using the reflective layer 37 . Moreover, the color of the light emitted by the light emitting unit 3 can be changed through the fluorescent conversion layer 38 .

In addition, as shown in FIG. 5A , the reflective layer 37A can also be disposed on the inner surface of the light-transmitting housing 31, and the reflective layer 37A also has an opening 371, which corresponds to the light-emitting surface of the light-emitting diode chip 33, and The fluorescent conversion layer 38 can also be disposed on the inner surface or the outer surface of the transparent casing 31 corresponding to the opening 371 . Here, the fluorescent conversion layer 38 is disposed on the inner surface of the light-transmitting housing 31 corresponding to the opening 371 as an example for illustration. In addition, please refer to FIG. 5B , the reflective layer 37B and the reflective layer 37C may also be provided on the inner surface and the outer surface of the transparent casing 31 at the same time. It should be noted that the reflective layer 37B and reflective layer 37C disposed on the inner and outer surfaces of the light-transmitting housing 31A are dislocated, but should avoid covering the light-emitting opening 371 .

Please refer to FIG. 6, the fluorescent conversion layer can also be replaced by a phosphor tape (phosphor tape) T, and the phosphor tape T is arranged on at least part of the outer surface of the light-transmitting housing 31 and/or The inner surface, here, the phosphor tape T is attached to the outer surface of the light-transmitting casing 31 as an example for illustration. The phosphor tape T, for example, has an adhesive layer T1 and a phosphor layer T2, and the phosphor layer T2 is doped with phosphor to change the color of the emitted light. It should be noted that the phosphor tape T can have different compositions according to different requirements.

In addition, the above-mentioned reflective layer is described as being disposed on the transparent casing as an example, however, the reflective layer may also be disposed on the surface of the substrate. Please refer to FIG. 7 , a light emitting diode chip 33 is disposed on a surface of the substrate 32 . A reflective layer 37D is disposed around the LED chip 33 on the substrate 32 . The reflective layer 37D is used to reflect the light emitted by the LED chip 33 to the substrate 32 , thereby increasing the utilization rate of the light emitted by the LED chip 33 . Wherein, if the substrate 32 is a transparent substrate, the reflective layer 37D may also be disposed on the other surface opposite to the LED chip 33 . The material of the reflective layer 37D is the same as that of the reflective layer in the above-mentioned embodiment, and will not be repeated here.

In addition, as shown in FIG. 8 , a reflective housing (lamp house) L may also be provided around the LED chip 33 on the circuit substrate 32 , so as to reflect and concentrate the light emitting direction of the LED chip 33 .

third embodiment

Please refer to FIG. 9A and FIG. 9B at the same time. The difference between the light emitting unit 4 of the third embodiment of the present invention and the first embodiment is that the enclosed space 411 of the light emitting unit 4 is composed of two housing components 412 and 413 . A plurality of LED chips 43 and at least two connecting electrodes 46 are disposed on the substrate 42 . The above LED chips 43 are arranged in a two-dimensional manner as an example, but it is not limiting. The encapsulant 45 encapsulates the LED chip 43 in the same manner as the first embodiment. The base plate 42 is interposed between the two casing elements 412 , 413 . Wherein, a reflective layer 47 can be arranged or formed on the substrate 42, and a fluorescent conversion layer 48 can be arranged or formed on the casing element 412, but it is not limiting, and its variations can also refer to the above-mentioned embodiments , of course, the fluorescent conversion layer can also be replaced by a fluorescent tape. In addition, the casing elements 412, 413 can also have a light-transmitting portion and a non-light-transmitting portion the same as the first embodiment, for example, the casing element 412 on the substrate 42 is a light-transmitting portion, and the casing under the substrate 42 is a light-transmitting portion. The element 413 is a non-light-transmitting part. In addition, at least one of the housing elements 412 and 413 may have a plurality of diffusers whose material is the same as that of the diffusers in the first embodiment, so details will not be repeated here.

After the housing elements 412 and 413 are arranged correspondingly, they can be combined by gluing or fusing to form the enclosed space 411 . Among them, the gluing method includes UV curing after sealing, thermal curing after sealing or natural drying after sealing. In addition, the housing components 412 and 413 can also be combined by locking or clipping first, and then combined by gluing or fusing.

In addition, please refer to FIG. 10 , the enclosed space 511 of the light emitting unit 5 can also be formed by a hollow casing 51 . The hollow casing 51 can also have a reflective layer and a fluorescent conversion layer, which are arranged on an outer surface and/or an inner surface of a part of the hollow casing 51. Of course, the fluorescent conversion layer can also be changed to utilize fluorescent light. body tape instead. Wherein, the cross-sectional shape of the hollow shell 51 is non-limiting, and it can be, for example, circular, elliptical, triangular, quadrilateral, polygonal or irregular, and can have different variations according to different designs, and the hollow shell The body 51 can have a plurality of scatterers as in the previous embodiments. The encapsulant 55 also encapsulates the LED chip 53 in the same manner as the first embodiment.

In addition, please refer to FIG. 11 , if the housing shape on the light-emitting surface of the light-emitting diode chip 53 is triangular, quadrilateral, polygonal or irregular, etc., the outer shell of the housing on each light-emitting diode chip 53 is The surface or the inner surface may have a lens structure S. Here, the lens structure S disposed on the outer surface of the hollow casing 51A is used as an example for illustration, but it is not limiting. In this way, the light emitted by the LED chip 53 can be concentrated.

To sum up, according to the light emitting unit of the present invention, the light emitting diode chip is placed in a closed space, and the light emitting diode chip is protected from external environmental factors such as moisture or dust through the casing. Therefore, the encapsulant of the light-emitting unit of the present invention has the function of improving the light-extraction efficiency and the light-extraction range of the LED chip. Since the volume thickness of the encapsulant is much smaller than that of the prior art, the wires connected between the light-emitting diode chip and the substrate can be prevented from being deformed or broken due to being pulled or squeezed. In addition, after the thickness of the encapsulant is reduced, the heat dissipation path of the LED chip can not only dissipate heat through the lower substrate, but also directly dissipate heat through the upper part, and if the enclosed space is filled with gas, liquid colloid, elastic colloid or oily fluid, etc., The thermal convection effect can further improve the heat dissipation effect of the LED chip.

In addition, the light emitting unit of the present invention may further include a reflective layer and a fluorescent conversion layer. In addition to fixing the light emitting direction on the light-transmitting shell provided with the reflective layer, the light emitted by the plurality of light-emitting diode chips can be mixed before the light in the light-transmitting shell. The fluorescent conversion layer can be used to change the light color of the light-emitting unit, so as to increase the application range of the light-emitting unit. The phosphor conversion layer can be replaced by phosphor tape to increase process efficiency and product reliability.

The above description is for illustration only, not for limitation. Any equivalent modification or change without departing from the spirit and scope of the present invention shall be included in the scope of the claims.

Claims (16)

1. a luminescence unit is characterized in that, comprises:

One substrate;

At least one light-emitting diode chip for backlight unit is arranged on this substrate with an adhesion material;

At least one lead, one first end is connected in this light-emitting diode chip for backlight unit, and one second end is connected in this substrate, and the central point of this second end and this light-emitting diode chip for backlight unit has one first distance, and the peak of this lead and this substrate have a second distance; And

At least one adhesive body, at least this light-emitting diode chip for backlight unit of cover part, and the cumulative volume of this adhesive body and this light-emitting diode chip for backlight unit is less than a cylindrical volume that is formed by this first distance and this second distance, wherein this first distance is this cylindrical radius, this second distance is this cylindrical height, and this light-emitting diode chip for backlight unit and the joint face of this substrate are that this second end with this lead is positioned at identical horizontal plane.

2. luminescence unit as claimed in claim 1 wherein, exposes to this adhesive body to this lead of small part.

3. luminescence unit as claimed in claim 1 wherein, more comprises:

One confined space, wherein this light-emitting diode chip for backlight unit, this lead and this adhesive body are positioned at this confined space.

4. luminescence unit as claimed in claim 3 wherein, more comprises:

One printing opacity housing, itself and this substrate links to form this confined space.

5. luminescence unit as claimed in claim 4 wherein, more comprises:

At least one phosphor body adhesive tape, be arranged at this printing opacity housing to the outer surface of small part and/or to the inner surface of small part.

6. luminescence unit as claimed in claim 3 wherein, more comprises:

At least two casing members, wherein this confined space is formed between the described casing member.

7. luminescence unit as claimed in claim 6 wherein, more comprises:

At least one phosphor body adhesive tape is arranged at one of them the part outer surface and/or the part inner surface at least of described casing member.

8. luminescence unit as claimed in claim 3 wherein, more comprises:

One hollow housing, wherein this confined space is formed in this hollow housing.

9. luminescence unit as claimed in claim 8 wherein, more comprises:

At least one phosphor body adhesive tape, be arranged at this hollow housing to the outer surface of small part and/or to the inner surface of small part.

10. as claim 4,6 or 8 described luminescence units, wherein, one of them or this hollow housing at least of this printing opacity housing, described casing member have a plurality of scattering objects.

11. luminescence unit as claimed in claim 10, wherein, described scattering object is scattering particles or scattering bubble.

12. luminescence unit as claimed in claim 3 wherein, more comprises:

One gas, filling is in this confined space.

13. luminescence unit as claimed in claim 12, wherein, this gas is nitrogen or noble gas.

14. luminescence unit as claimed in claim 3 wherein, is a vacuum in this confined space.

15. luminescence unit as claimed in claim 3 wherein, more comprises:

A colloid or a fluid, filling is in this confined space.

16. luminescence unit as claimed in claim 1, wherein, the emission spectrum of this light-emitting diode chip for backlight unit comprises visible-range and/or ultraviolet light range.

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