Patent Application
20050173713
The present invention is related to a light-emitting diode (LED) device, particularly to a LED device with at least three pins, having not only an electrostatic protective effect and high heat-dissipation efficiency, but also raised brightness thereof.
Owing to several advantages, such as small volume, low weight, low power consumption, and long service life, as examples, light-emitting diodes (LEDs) have been widely used in computer peripherals, communication products, and other electronic apparatuses.
Referring to
When a working power source is fed into the first lead frame 151 and second lead frame 153, the light-emitting die 11 may emit a light source and project it forwardly. Although the fundamental luminescent function is provided for this LED device 10, there is no limit on voltage. Therefore, the damage to the light-emitting die 11 may occur extremely easily owing to the excessively high voltage between two terminals of the first electrode 111 and second electrode 113 of the light-emitting die 11, if an electrostatic protective effect is generated.
For avoiding such damage phenomenon to the light-emitting die 11 resulted from the electrostatic protective effect, a LED with electrostatic protective function, as shown in
How to discharge heat, generated when irradiating, in order to keep the temperature of the light emitting die at an approximate working temperature becomes an important issue as the luminous emittance increases, because the increasing area of the light-emitting die or the larger working current supplied therefor has become a tendency for increasing the luminous emittance of the LED device. Although a simple electrostatic protective function is provided in the aforementioned LED, the raised working temperature, and thus the lowered luminous efficiency of the light-emitting die may occur easily, due to the fact that it is incapable of discharging heat generated along with irradiance timely. Moreover, the first lead 131, the first electrode 111, and the second lead 233 are placed on the projection path of the light source, in such a way that the shading effect may occur extremely easily, thus lowering brightness of the LED device 20 correspondingly.
For this purpose, how to design a novel light-emitting diode (LED) device, which may not only have the effect of preventing electrostatic damage, but also provide a superior heat-dissipating path, and enhance brightness thereof, aiming at the disadvantages of the above conventional art, is the key point of the present invention.
Accordingly, it is the primary object of the present invention to provide a multi-pin LED device including an accommodating base connectedly provided with at least one outwardly-extending heat-dissipating pin served for timely and directly discharging the working heat source, generated by a light-emitting die disposed within the accommodating base, and then controlling the temperature of the light-emitting device at an appropriate working temperature, in order to enhance the luminous efficiency.
It is the secondary object of the present invention to provide a multi-pin LED device having heat-dissipation function and electro-conductive pins disposed independently among each other, so as to eliminate the safety problem of electric leakage, which may occur if the heat-dissipation function and the electroconductivity are provided by a common pin.
It is another object of the present invention to provide a multi-pin LED device capable of being produced massively by means of an existed manufacturing process without additionally invested vast cost.
It is still another object of the present invention to provide a multi-pin LED device having light-emitting dies adhered onto an electrostatic discharge protection device in the manner of flip-chip, in such a way that the block for the projection light source provided by a first lead wire and a second lead wire is avoided, further enhancing brightness of the LED device.
For the purpose of achieving aforementioned objects, the present invention provides a multi-pin LED device, the main structure thereof comprising: an electrostatic discharge protection device having a first protective electrode and a second protective electrode; at least one light-emitting die fixedly provided on the electrostatic discharge protection device, the first electrode and the second electrode of each light-emitting die capable of being electrically connected to the corresponding first protective electrode and second protective electrode, respectively; an accommodating base used to fix the light-emitting die and the electrostatic discharge protection device, and connectedly provided with at least one heat-dissipating pin at the bottom thereof; at least one first electro-conductive pin electrically connected to the first protective electrode; and at least one second electro-conductive pin electrically connected to the second protective electrode.
The structural features and the effects to be achieved may further be understood and appreciated by reference to the presently preferred embodiments together with the detailed description.
Referring to
The light-emitting die 31 includes a first electrode 311 and a second electrode 313, while the electrostatic discharge protection device 37 at least includes a first protective electrode 371 and a second protective electrode 373. For the light-emitting die 31, the flip-chip method is used such that the first electrode 311 and the second electrode 313 of the light-emitting die 31 may be electrically connected to the corresponding first protective electrode 371 and the second protective electrode 373, respectively.
By means of silver adhesive, solder paste, AuSi, AuSn, or other thermally conductive materials, the electrostatic discharge protection device 37 may be directly adhered to the bottom of the accommodating base 359 provided with a heat-dissipating pin 355 extending outwardly. At the side of the accommodating base 359, there are provided with the first electro-conductive pin 351 and the second electro-conductive pin 353, to which the first protective electrode 371 and the second protective electrode 373 are electrically connected, correspondingly, via a first lead wire 331 and a second lead wire 333, respectively. The projection path from the light source may be not blocked by the first and second lead wires 331 and 333, resulting in raised brightness of the light-emitting element, due to the fact that the light-emitting die 31 is adhered onto the electrostatic discharge protection device 37 in the manner of flip-chip.
Moreover, on the exterior of the light-emitting die 31, electrostatic discharge protection device 37, accommodating base 359, first lead wire 331, second lead wire 333, top end of the first electro-conductive pin 351, and top end of the second electro-conductive pin 353, there may be provided with a protective layer 39 made from the material, such as glass, plastic, epoxy, for example, in order to protect internal structure from being damaged by the contact with external air. The protective layer 39 is also made as a convex lens, concave lens, and so forth, in such a way that the beam projected from the light-emitting die 31 may be uniformly dispersed or concentratedly projected depending upon the actual purpose.
Owing to AuSi, AuSn, silver adhesive, solder paste, or other adhesive material with high coefficient of thermal conductivity, which may be used to bond the electrostatic discharge protection device 37 onto the inner side of the accommodating base 387, in addition to the material with high coefficient of thermal conductivity, for instance Cu, Al, etc., which may be used to produce the accommodating base 359 and the heat-dissipating pin 355 extendingly outside of the protective material 39 therefrom, the heat source generated from the light-emitting die 31 may be discharged rapidly via the accommodating base 359 and the heat-dissipating pin 355, enabling the light-emitting die 31 to maintain a constant working temperature, further keeping the light-emitting die 31 at a constant working temperature. Therefore, increased luminous efficiency and prolonged service life may be obtained.
It is important for the heat to be transmitted to a circuit board (not shown) from the first electro-conductive pin 351, thus avoiding temperature rising of the circuit board, if the LED device 30 is installed on the circuit board, because the first electro-conductive pin 351 and the heat-dissipating pin 355 of the present invention are not interconnected together. Moreover, for the heat-dissipating pin 355 itself, no additional high working temperature is generated because it is not electrified, thereby the heat-dissipation effect of the light-emitting die is not affected. Meanwhile, the safety problem resulted from electric leakage may be avoided owing to independent heat-dissipation function and nonconductivity inherent to the heat-dissipating pin 355. An enhanced heat-dissipation effect may be achieved, of course, if the circuit board is designed with a heat-dissipating device (not shown) to which the heat-dissipating pin 355 may be also connected.
In addition, for the light-emitting die 31 which generates lower working temperature, it is still possible to connect one of the first electro-conductive pin 351 and the second electro-conductive pin 353 to the thermally conductive pin directly 355. As such, heat may be transmitted to a heat-dissipating device (not shown) on the circuit board via this one of the first electro-conductive pin 351 and the second electro-conductive pin 353.
The light-emitting die 31 is fixedly provided on the electrostatic discharge protection device 37 in the manner of flip-chip in the above embodiment, though, the light-emitting die 31 may be fixedly provided on the accommodating base 359 directly such that the first electrode 311 and the second electrode 313 of the light-emitting die 31 are directly and electrically connected to the first electro-conductive pin 351 and the second electro-conductive pin 353, correspondingly, as well, in another application field, if misgivings about the damage to the device resulted from the effect of electrostatic discharge may not present. Therefore, the working heat source generated from the light-emitting die 31 may be still discharged rapidly via the heat-dissipating pin 355.
Subsequently, referring to
Finally, referring to
Owing to the simple structure, high reliability, such a LED device having both of the electrostatic protective function and high heat-dissipation efficiency may be produced by the existed manufacturing equipment without investing additional vast cost.
The foregoing description is merely one embodiment of present invention and not considered as restrictive. All equivalent variations and modifications in process, method, feature, and spirit in accordance with the appended claims may be made without in any way from the scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 093102849 | Feb 2004 | TW | national |
