TWI385781B - Lead frame - Google Patents

Description

Lead frame

The present invention relates to a lead frame that can carry a plurality of light-emitting wafers, and more particularly to a lead frame that prevents external moisture from penetrating into contact with the light-emitting wafer.

In recent years, LEDs have become more and more popular in applications due to their short size and low heat. At present, the mainstream application of LED is the backlighting of electronic products, such as mobile phones, notebook computers and televisions. The backlights that these electronic products generally require are white light, and the production of white LEDs is one of the important topics in the LED industry. At present, the production method of white LEDs can be roughly divided into excitation of phosphor powder or use of three primary color LEDs (red, blue, green). The way to stimulate the fluorescent powder to light out can be roughly divided into blue LED with yellow fluorescent powder, blue LED with red and green fluorescent powder or ultraviolet LED with three primary fluorescent powder. In general, RGB three-color LED mixed light has the advantages of high color saturation and high luminance, so it is widely used in high-end electronic products.

In addition, in the lighting market, LEDs have gradually replaced traditional lighting fixtures, such as automotive headlights, searchlights, and indoor lighting. Since the above lighting market must have sufficient light intensity to be able to identify objects at a distance, a light-emitting device with high-intensity illumination has been gradually developed on the market. As shown in Figure 1, it is a light-emitting device that is currently available on the market with high-brightness illumination.

Since the light-emitting device 1 having high-brightness light-emitting capability, whether by using the excitation fluorescent light-emitting method or the RGB three-color LED light mixing method, a plurality of light-emitting diodes 12 are required to be disposed on the lead frame 10, which may be practically applied. Up to tens or even one hundred or more light-emitting diodes 12 are described herein only by providing a plurality of light-emitting diodes 12. Therefore, the pedestal 102 must form a large area, so that the plurality of illuminating diodes 12 are simultaneously arranged above the susceptor 102, and the thermal energy generated by the plurality of illuminating diodes 12 can be transmitted through the susceptor 102 for thermal energy. Pass and then expel it outward. In order to solve the heat dissipation problem, a heat dissipating member 14 is attached to the bottom of the base 102 so that heat can be transmitted to the heat dissipating member 14 through the base 102. Further, the heat radiating member 14 exchanges heat with the air to achieve rapid heat dissipation.

However, in order to provide the susceptor 10 having a plurality of illuminating diodes 12, in order to provide the susceptor 102 having a large heat dissipating area, the pedestal 102 is formed into a flat shape, and the insulating body 100 is formed over the susceptor 102, and The area of the susceptor 102 is larger than the insulative housing 100. When the insulative housing 100 is formed on the base 102, a plurality of through holes 1024 are formed in the base 102 so that the insulative housing 100 can be fixed to the base 102 through the through holes 1024. In order to be coupled with the heat dissipating member 14, the base 102 must be provided with a locking hole 1026 so that the base 102 can be locked to the heat through the locking component 16 (screw as shown in FIG. 1). On member 14.

In the foregoing structure, the insulative housing 100 is coupled to the base 102 only through the through hole 1024. However, the insulative housing 100 is bonded to the base 102 by injection molding. Therefore, a horizontal bonding surface is formed between the insulative housing 100 and the base 102. However, the insulative housing 100 is formed on the base 102 by injection molding. The insulative housing 100 and the base 102 are made of two different materials. Therefore, the insulative housing 100 cannot be effectively and closely attached to the base 102. Therefore, the insulative housing 100 is required to pass through the through hole 1024. The combination of the bases 102.

However, since the insulative housing 100 is bonded to the base 102 by injection molding, the injection molding must undergo a process of cooling and shrinking, so that the deformation of the insulative housing 100 is easily caused, resulting in a sticker between the insulative housing 100 and the base 102. The mating surface cannot be in close contact with each other, and a gap is formed between the insulative surface of the insulative housing 100 and the base 102, so that the water vapor is entrained in the air, and the gap generated by the unadhesive bonding surface enters the insulation. In the solid crystal region generated by the body 100 and the susceptor 102, a problem of moisture infiltration occurs, causing damage to the light-emitting diode 12 inside the solid crystal region. In addition, the pedestal 102 is coupled to the heat dissipating member 14 through the locking component 16 . Therefore, during the locking process, the warping deformation of the susceptor 102 is also easily caused by the unevenness of the locking force, so that the insulating body 100 and the base are The gap between the seats 102 is increased, or the gap is increased, which causes the infiltration of water and gas to be intensified, which seriously affects the performance of the light-emitting device 1, and is more likely to cause failure of the light-emitting diode 12 and shorten its service life.

Therefore, how to provide a lead frame for a high-intensity light-emitting device that has an excellent heat dissipation effect and can effectively prevent moisture from penetrating and thereby prolonging the service life is a problem to be solved in the present invention.

One aspect of the present invention is to provide a lead frame for a high-intensity light-emitting device that has an excellent heat dissipation effect and can effectively prevent moisture from penetrating and thereby prolonging the service life.

To achieve the above, according to a first embodiment of the present invention, the lead frame of the present invention comprises a base, an insulative body and a bracket. The base includes an upper end surface and a lower end surface, and the upper end surface further includes a first surface and a second surface. The insulating body partially covers the pedestal and simultaneously forms a solid crystal region with the first surface to carry the plurality of luminescent wafers by the solid crystal region. The first surface is defined as a height reference plane and the lower end surface is lower than the first surface. The first surface has a height difference from the second surface. The bracket is partially covered by the insulative housing and includes a first connecting portion electrically connected to the light emitting chips and a second connecting portion electrically connected to the circuit.

The effect of effectively preventing moisture from penetrating into the light-emitting device is achieved by the height difference formed by the first surface and the second surface.

Further, according to the second embodiment of the present invention, the upper end surface of the base further includes a third surface, and the third surface, the first surface, and the second surface have a height difference therebetween. The third surface is disposed between the first surface and the second surface.

According to a third embodiment of the present invention, the upper end surface of the base further includes a fourth surface, and the fourth surface, the third surface, the first surface, and the second surface have a height difference therebetween. The third surface is disposed adjacent to the fourth surface between the first surface and the second surface.

Therefore, according to the above specific embodiments, the pedestal of the lead frame of the present invention utilizes a plurality of surfaces formed with a height difference therebetween to form a more complicated contact area between the insulating body and the pedestal, so that the water is After the gas penetrates from the gap between the insulating body and the pedestal, the length of the water gas infiltration path can be extended to change the flow direction of the water gas to increase the difficulty of water gas infiltration, thereby effectively preventing water and gas from penetrating into the solid crystal. The area is in contact with the illuminating wafer to prevent the illuminating diode from failing or shortening its service life.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

The lead frame of the present invention is mainly applied to a light-emitting device having high-intensity illumination, and therefore needs to carry a plurality of light-emitting chips, which can carry tens or more than one hundred. In fact, the luminescent wafer can be a light emitting diode, a laser diode or other semiconductor light emitting structure.

In contrast to prior art leadframe 10 (shown in Figure 1), the pedestal of the leadframe of the present invention includes a plurality of surfaces having a height difference therebetween to prevent moisture from penetrating into the illuminating device. As shown in the lead frame 20 of FIG. 2B, the upper end surface 2020 of the susceptor 202 includes a first surface 20200 and a second surface 20202 lower than the first surface 20200, such that the first surface 20200 and the second surface 20202 are formed. There is a high and low drop. In addition, it should be added that in order to make all embodiments have a clear height and positive and negative direction definition, the first surface of the pedestal is defined as a height reference plane, and the lower end surface of the pedestal is defined lower than the first a surface.

When the water entrained in the air penetrates into the second surface 20202 through the gap between the insulative housing 200 and the base 202, the infiltration path of the water vapor encounters a turning point formed by a similar surface having a height difference, turning It can block the infiltration of moisture and even the reverse flow of water. Moreover, the water gas needs to overcome the height difference to penetrate into the first surface 20200, and relatively lengthens the path length of the water gas to be infiltrated into contact with the light-emitting diode 4. Moreover, since the height difference is formed between the first surface 20200 and the second surface 20202, when the insulating body 200 is formed on the base 202, the insulating body 200 fills the height difference and is packaged. Covering the periphery of the first surface 20200, the insulating body 200 forms a better close fit with the periphery of the first surface 20200, thereby preventing moisture from penetrating into the first surface 20200. Further, the lead frame 20 of the present invention achieves the purpose of blocking the penetration of external moisture into the solid crystal region 20204 and contacting the light-emitting diode 4.

Furthermore, the upper end surface of the pedestal may include more surfaces having a height difference therebetween, as shown by the lead frame 21 in FIG. 3A and the lead frame 22 in FIG. The upper end surface 2120 of the susceptor 212 in FIG. 3A and FIG. 3B further includes a third surface 21204, which is higher than the first surface 21200 and the second surface, as compared with the pedestal 202 in FIG. 21202. Compared with the pedestal 212 in FIG. 3A, the upper end surface 2220 of the pedestal 222 in FIG. 4 further includes a fourth surface 22206, and the fourth surface is lower than the first surface 22200 and the second surface 22202. Thereby, the contact surface between the insulating body and the pedestal has more turning points capable of blocking the penetration of moisture, and relatively prolongs the infiltration path of moisture from the outside to the solid crystal region. In addition, the insulating body can be more closely attached to the pedestal by filling a plurality of turning points (that is, at the height difference) to prevent external moisture from penetrating into the lead frame.

In addition, the substrate 202 of the lead frame 20 shown in FIG. 2D is substantially the same size as the insulative housing 202. Therefore, the insulating body 200 and the base 202 (as shown in FIG. 2C) need to be opened with a locking hole for the screw. The locking hole can be locked, and the lead frame 20 is locked on the heat dissipating member 5 (as shown in FIG. 2D). However, the lead frame of the present invention is not limited thereto, and the base 232 of the lead frame 23 shown in FIG. 5 is smaller in size than the insulating body 230, so that only a locking hole is required to be opened on the insulating body 230, and the screw does not pass through the substrate. 232 and locked into the heat dissipating member. Since the insulative housing 230 can absorb a part of the locking force, and the substrate 232 is not directly stressed (not through the screw), when the lead frame 23 is locked on the heat dissipating member 5, the substrate 232 is less likely to be warped and deformed. Therefore, the gap between the insulating body 230 and the substrate 232 is not generated or increased, and the moisture is prevented from penetrating into the lead frame 23.

Since the injection molded insulating body is cooled or contracted or the base is locked by the locking force, a gap is formed between the base and the insulating body. If the bonding force between the insulating body and the pedestal is larger, the resulting gap will be relatively smaller. In order to tightly engage the insulating body and the base, in addition to indirectly utilizing the locking force of the screw, the direction of the joining force between the insulating body and the base can be increased. A plurality of through holes may be disposed on the base, as shown in FIG. 2B and FIG. 2C, the base 202 including the plurality of through holes 2024, and a groove may be disposed around the base, as shown in FIG. 6A and FIG. Base 242 shown in B. The insulative housing 240 fills the recess 2424 during injection molding, thereby increasing the longitudinal engagement force between the insulative housing 240 and the base 242 (as indicated by the arrow direction in FIG. 6A).

In addition to the purpose of blocking moisture infiltration, the leadframe of the present invention may have other variations in structure and materials to more quickly dissipate or direct the heat generated by the LED. Of course, the base of the lead frame described below still contains a plurality of surfaces having a height difference therebetween to achieve the main purpose of preventing moisture from penetrating.

In order to quickly dissipate the heat generated by the high-intensity illumination device, the base of the lead frame can be made of a material having a high thermal conductivity. Generally, the material of the pedestal is aluminum or copper, and the pedestal of the lead frame is theoretically all made of copper having a higher thermal conductivity, but the cost of copper is more expensive than aluminum. Therefore, the actual method is to combine two parts made of different materials into a base, as shown in the base 252 of FIG. 5A and FIG. 5B, the base 252 includes a first sub-base 2520 and a second sub-base. Block 2522. The material of the first sub-mount 2520 is copper, and the material of the second sub-base 2522 is aluminum. The first sub-base 2520 of small size and copper is used to carry a plurality of light-emitting diodes to quickly conduct heat. The second sub-base 2522 of larger size and aluminum can accommodate the first sub-mount 2520. In addition to helping to dissipate the heat conducted by the first sub-mount 2520, the second sub-base 2522 having a larger area is further The amount of heat exchange with the heat dissipating member can be increased to dissipate heat quickly. Further, the susceptor 252 takes into consideration the heat dissipation rate and the manufacturing cost.

In addition to the above method using a high thermal conductivity material, the heat dissipation rate can be increased by increasing the heat dissipation area, as shown in FIGS. 8A to 8C. The base 262 of the leadframe 26 in FIG. 8A includes a heat sink 2624 that protrudes symmetrically outwardly from the insulative housing 260. For example, the heat dissipation plate 2624 in FIG. 8B protrudes outward from the two sides of the insulative housing 260, and the heat dissipation plate 2624 in FIG. 6C protrudes outwardly around the insulative housing 260. The heat dissipation plate 2624 protruding from the insulative housing 260 can not only increase the heat dissipation area, but also interconnect the respective heat dissipation plates 2624 between the plurality of lead frames 26 to disperse heat evenly, thereby avoiding excessive concentration of heat.

In addition, the method of increasing the heat dissipation rate may also protrude from the lower edge of the insulative housing 270 as shown in FIG. The heat dissipating member 6 includes a concave space that is matched with the protruding portion of the susceptor 272, thereby increasing the contact area between the susceptor 272 and the heat dissipating member 6 to increase heat dissipation efficiency. Of course, the present invention is not limited thereto, and the pedestal may also include a concave space embedded in the protruding portion of the heat dissipating member.

In addition, the lead frame of the present invention may have other variations to suit different applications, such as the manner of connection to the circuit, the manner of connection to the light emitting diode, and the appearance. Of course, the base of the lead frame described below still contains a plurality of surfaces having a height difference therebetween to achieve the main purpose of preventing moisture from penetrating.

The bracket 204 of the lead frame 20 in FIG. 2B is embedded in the insulative housing 200 except that the first connecting portion 2040 is electrically connected to the LED 4, and is exposed only in the manner of connecting the lead frame and the circuit. The second connecting portion 2042 is electrically connected to the external circuit through the wiring to provide the power of the light emitting diode 4. Of course, the method of setting the bracket is not limited thereto, and the bracket may protrude from the insulating body, as shown in FIG. 10A to FIG. Depending on the actual soldering of the board and the bracket, the second connection protruding from the insulative housing and connected to the board can remain flat or curved to facilitate soldering. For example, if the leadframe 28 is embedded in a recessed area of the circuit board (shown in phantom), as shown in FIGS. 10A and 10B, the second connecting portion 2842 of the bracket 284 can remain flat to be close to the circuit board. If the lead frame 28 is placed directly on the circuit board (shown in dashed lines), as shown in FIG. 10C, the second connecting portion 2842 needs to be bent to be close to the circuit board. Thereby, the solder paste on the circuit board can be easily adhered to the second connection portion 2842 when the tin furnace is passed.

For example, in the connection manner of the bracket of the lead frame and the LED, one row of the LEDs 4 arranged in an array in FIG. 2A is taken as an example, and the first connecting portion 2040 of the bracket 240 shown in FIG. The light-emitting diodes 4 closest to the first connecting portion 2040 are electrically connected to the light-emitting diodes 4, and the other light-emitting diodes 4 are electrically connected to each other only by wires. If one of the light-emitting diodes 4 of the column of LEDs 4 fails, the column of LEDs 4 cannot emit light. Therefore, the bracket 294 shown in FIG. 11 includes a plurality of first connecting portions 2940, and each of the first connecting portions 2940 is connected to the second connecting portion 2942. Each of the first connecting portions 2940 is elongated and electrically connected to each of the LEDs 7 of the column of the LEDs. Therefore, one of the LEDs 7 in the column is damaged and does not affect other components. The light-emitting diode 7 operates.

In appearance, since the size of the light-emitting diode is much smaller than that of a general lamp or a light bulb, the lead frame carrying the light-emitting diode can be easily changed according to actual application or manufacturing requirements. , as shown in Figure 12 and Figure 13. The base 302 in FIG. 12 has a circular shape, and the base 312 in FIG. 13 has an elliptical shape, and the insulative housing 310 has a circular shape. Of course, the appearance of the base 302, the base 312, and the insulative housing 310 is not limited thereto, and may be a triangle or other polygon.

It should be noted that the susceptor and the bracket depicted in the above various embodiments are separated, that is, the thermoelectric separation type lead frame. However, the lead frame of the present invention is not limited thereto, and the base may be integrally formed with one of the brackets, that is, the thermoelectric type lead frame.

Compared with the prior art, the base of the lead frame of the present invention utilizes a plurality of surfaces formed with a height drop therebetween to form a more complicated contact area between the insulating body and the base, so that the water vapor is from the insulating body. After infiltrating into the gap between the base and the base, the length of the water infiltration path can be extended to change the flow direction of the water vapor to increase the difficulty of infiltration of water and gas, thereby effectively preventing the infiltration of water and gas into the solid crystal region and the light emitting wafer. Contact to prevent the LED from failing or shortening its service life. Furthermore, in addition to the through hole or the recess, the base of the lead frame of the present invention can utilize a locking component to increase the bonding force between the base and the insulating body, thereby reducing the insulating body and the base. The gap between them can reduce the amount of moisture infiltration. In addition, the lead frame of the present invention may have a heat sink protruding from the insulating body and a substrate made of a different material to increase heat dissipation efficiency. In summary, the lead frame of the present invention has an excellent heat dissipation effect, and can effectively prevent moisture from infiltrating, thereby prolonging the service life of the high-intensity light-emitting device.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1. . . Illuminating device

10, 20, 21, 22, 23, 26, 28. . . Lead frame

100, 200, 230, 240, 260, 270, 280, 310. . . Insulating body

102, 202, 212, 222, 232, 242, 252, 262, 272, 302, 312. . . Pedestal

12, 4, 7. . . Light-emitting diode

14, 5, 6. . . Heat sink

16. . . Locking member

204, 284, 294. . . support

2022. . . Lower end

2020, 2120, 2220. . . Upper end

1026. . . Locking hole

1024, 2024. . . Through hole

2424. . . Groove

2624. . . Radiating plate

2520. . . First sub-base

2522. . . Second sub-base

21204. . . Third surface

22206. . . Fourth surface

20204. . . Solid crystal region

2040, 2940. . . First connection

2042, 2842, 2942. . . Second connection

20200, 21200, 22200. . . First surface

20202, 21202, 22202. . . Second surface

Figure 1 is a schematic view showing a lead frame of the prior art.

Figure 2A is a schematic view of a lead frame according to a first embodiment of the present invention.

Figure 2B is a cross-sectional view of the lead frame of Figure 2A taken along line A-A.

Figure 2C is a schematic view of the base and the bracket of Figure 2A.

Figure 2D is a schematic view showing the bonding of the lead frame and the heat sink in Figure 2A.

Figure 3A is a schematic view of a lead frame according to a second embodiment of the present invention.

Figure 3B is a schematic view of the susceptor in Figure 3A.

Figure 4 is a schematic view showing a lead frame according to a third embodiment of the present invention.

Figure 5 is a schematic view showing a lead frame according to a fourth embodiment of the present invention.

Figure 6A is a schematic view showing a lead frame according to a fifth embodiment of the present invention.

Figure 6B is a schematic view of the susceptor of Figure 6A.

Figure 7A is a schematic view showing a lead frame according to a sixth embodiment of the present invention.

Figure 7B is a schematic view showing the first sub-base and the second sub-base in Figure 7A.

Figure 8A is a schematic view showing a lead frame according to a seventh embodiment of the present invention.

Figure 8B is a perspective view corresponding to the lead frame of Figure 8A.

FIG. 8C is another perspective view corresponding to the lead frame in FIG. 8A.

Figure 9 is a schematic view showing a lead frame according to an eighth embodiment of the present invention.

Figure 10A is a schematic view showing a lead frame according to a ninth embodiment of the present invention.

Figure 10B is a cross-sectional view of the lead frame taken along line A-A of Figure 10A.

Figure 10C is a schematic view showing the lead frame of Figure 10B including a bent bracket.

Figure 11 is a schematic view showing a lead frame according to a tenth embodiment of the present invention.

Figure 12 is a schematic view showing a susceptor according to an eleventh embodiment of the present invention.

Figure 13 is a schematic view showing a lead frame according to a twelfth embodiment of the present invention.

4. . . Light-emitting diode

20. . . Lead frame

200. . . Insulating body

202. . . Pedestal

204. . . support

2020. . . Upper end

2022. . . Lower end

2024. . . Through hole

20204. . . Solid crystal region

2040. . . First connection

2042. . . Second connection

20200. . . First surface

20202. . . Second surface

Claims (10)

A lead frame for carrying a plurality of light-emitting chips, comprising: a base comprising an upper end surface and a lower end surface, the upper end surface comprising a first surface and a second surface; an insulating body partially covering the The pedestal and the first surface form a solid crystal region, wherein the solid crystal region is used to carry the illuminating wafers, and the first surface is defined as a height reference surface and the lower end surface is lower than the first surface, the first a surface having a height difference from the second surface; and a bracket partially covered by the insulative housing, comprising a first connection portion electrically connected to the light emitting chip and a second connection electrically connected to a circuit The upper end surface of the base includes a third surface, and the third surface, the first surface and the second surface have a height difference therebetween, and the third surface is disposed on the first surface and Between the second surfaces, the first surface and the second surface are both higher than the third surface. The lead frame of claim 1, wherein the first surface is higher than the second surface. The lead frame of claim 1, wherein the lower end surface is exposed to the insulating body. The lead frame of claim 3, wherein the lower end surface protrudes from the insulating body. The lead frame of claim 1, wherein the second connection The joint protrudes from one side of the insulating body. The lead frame of claim 1, wherein the base comprises a through hole, and the insulating body fills the through hole. The lead frame of claim 1, wherein one side of the base comprises a recess, and the insulating body fills the recess. The lead frame of claim 1, wherein the base comprises a heat dissipation plate that protrudes symmetrically outwardly from the insulating body. The lead frame of claim 1, wherein the upper end surface of the base comprises a fourth surface, the fourth surface, the third surface, the first surface and the second surface Each has a height difference, and the third surface is disposed adjacent to the fourth surface between the first surface and the second surface. The lead frame of claim 9, wherein the third surface is higher than the first surface and the second surface, the fourth surface being lower than the first surface and the second surface.