This application claims the priority benefit of Taiwan application serial no. 96145693, filed on Nov. 30, 2007. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.
1. Field of Invention
The present invention relates to a light-emitting device and manufacture method thereof. The light-emitting device integrates the functions of an electronic substrate and a heat-dissipation module to manage the thermal conducting and electrical conducting individually. Volume of the light-emitting device can be reduced and accordingly the application field of the same is wide. The light-emitting device can be further incorporated with the existing lamp holder to form a light bulb for illumination.
2. Description of Related Art
Light-emitting diode (LED) is characterized by long life time, high illumination, high illuminating efficiency, and low power consumption and has the potential to become the mainstream of the future illuminating light source instead of the conventional one due to its high reliability, short response time, and high color definition and color rendering index. However, the present LED light bulbs are usually fabricated by multiple-level-package with several packaging interfaces, which may cause thermal resistance, especially heat may accumulate on the printed circuit board and lead to a low heat-dissipation efficiency. Due to the insufficient heat-dissipation capability, the temperature of LED can not be effectively reduced, which results in low illuminating efficiency and short life time.
In addition, when the number of LED is increased for a higher illumination, the number of source electrodes is accordingly increased, which results in the aforementioned problem of lower heat-dissipation and gets troubles in arranging the electrodes and occupying more available area.
Moreover, one skilled in the art has electrically connected the LED to a heat-dissipation base material for a ground signal. The heat-dissipation base material is capable of heat-dissipating and grounding simultaneously. However, the heat-dissipation base material may contact with other conductors and make the circuitry short to damage the LED and reduce the yield factor. To prevent the above problem, the size and profile of the heat-dissipation base material shall be limited.
Furthermore, although the LED is gradually applied in illumination, it is not compatible with the present lamps yet. The problem of incompatibility not only limits the illuminating application of LED, but also requires a lot of cost to replace the incompatible lamps for LED, which is neither economical nor environmentally friendly.
The main object of the present invention is to provide a composite structure and packaging method of a heat-dissipation module, wherein light-emitting diodes (especially LED chip die) are directly packaged on a post-like metal material in the form of “chip on heat-dissipation board”, to achieve high thermal conductivity and high stability to prevent heat accumulation in a printed circuit board and thus prolong the life time of light-emitting diodes.
Another object of the present invention is to provide a post-like metal material that can electrically connect the LED with the printed circuit board so as to decrease the overall area of the light-emitting device and increase its application range.
Another object of the present invention is to provide a light-emitting device, which can avoid the electrical short between the post-like metal material and other conductors, and thus improve the product yield.
Further another object of the present invention is to incorporate the light-emitting device with an existing lamp holder, wherein the light-emitting device can be directly adopted for illumination without replacing any present lamp equipment.
The manufacture method of the light-emitting device of the present invention includes: providing a post-like metal material having at least one through hole; providing at least one conductor surrounded with insulator in the through hole of the post-like metal material, wherein the conductor is post-like and two ends of the conductor are plated with metal by evaporation for being as electrodes; providing a printed circuit board having at least one electrode thereon, and electrically connecting one electrode at one end of the conductor to the electrode on the printed circuit board, such that the post-like metal material and the printed circuit board are incorporated into a composite heat-dissipation substrate having functions of thermal and electrical conduction; afterwards, providing and adhering a light-emitting diode to the post-like metal material; then, providing wires to electrically connect electrode of the light-emitting diode and the other electrode of the conductor through wire bonding, so as to form a complete electrical circuit for transmitting current; and finally, disposing phosphors and using an encapsulating material as a packaging material, to form the light-emitting device of the present invention.
In addition, concerning the method of integrating the post-like metal material, the conductor, and the insulator, the conductor can be encapsulated with the insulator first, and then the conductor and the insulator are inserted into the through hole of the post-like metal material as a whole. The second method is to dispose the conductor and the insulator separately into the through hole of the post-like metal material, wherein the insulator can be powdered and located between the conductor and the post-like metal material. Then, the conductor, the insulator, and the post-like metal material can be integrated together through a high-temperature sintering process. The third method is to providing a post-like metal material having a first surface and a second surface. Then, a ring groove is formed on the first surface forwarding the second surface. The conductor is formed by a part of the post-like metal material surrounded by the ring groove. Next, the insulator is filled into the ring groove and a high-temperature sintering process is conducted to combine the conductor, the insulator, and the post-like metal material together. Thereafter, the thickness of the post-like metal material is decreased by grinding, scraping, or digging the post-like metal material along the direction from the second surface to the first surface to expose the conductor and the insulator from the second surface.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the present invention as claimed.
The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The present invention is not restricted to the present embodiments, and can be realized in a wide variety of ways. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. Different parts of elements in the figures are not drawn to scale; some dimensions have been exaggerated to give a clearer description and understanding of the present invention.
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In order to avoid oxidation of the wires 50 in the atmosphere, encapsulating material 60 can be used as a packaging material. The encapsulating material 60 can be silicon rubber, and the packaging area shall include the first surface 11 of the post-like metal material 10 and covers at least the electrode 25 on the top end 211 of each conductor 21, the light-emitting diodes 40, and the wires 50, so as to isolate the aforementioned devices from the atmosphere, to form the light-emitting device 1 of the present invention. Furthermore, phosphors 70 can be disposed around the light-emitting diodes 40 so as to change the color of the light emitted by the light-emitting diodes 40. Hence, the addition of phosphors 70 is optional. The phosphors 70 can be disposed individually before packaging or be doped into and mixed with the encapsulating material 60 for packaging.
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The lamp holder 9 includes a stand 91 being metallic and tube-like, and a shade 92 being cup-like and disposed beside the stand 91, wherein the shade 92 includes an inner side 921 and an outer side 922. The light-emitting device 1 is disposed at the inner side of the shade 92. The shade 92 is an insulator made of ceramic materials or polymer, or can be metallic. The inner side 921 of the shade 92 can be plated with metal such as aluminum, nickel, or silver to form a reflective layer, so as to converge and amplify the output light of the light-emitting device 1. The first electrical signal input 911 and the second electrical signal input 912 on the stand 91 are electrically connected to the first and second input electrodes 33, 34 on the printed circuit board 30 of the light-emitting device 1 through conducting wires 913, respectively, so as to provide electrical signals to the light-emitting device 1, and then the light-emitting device 1 emits light.
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The manufacture method of a light-emitting device 1 of a LED in the present invention includes the following steps: providing a post-like metal material 10, which includes a first surface 11, a second surface 12, and a plurality of through holes 13 passing through the first surface 11 and second surface 12; providing a plurality of conductors 21 encapsulated by insulators 20 and disposed in the through holes 13 of the post-like metal material 10, wherein the conductors 21 are post-like; providing a printed circuit board 30, wherein the printed circuit board 30 includes a top surface 31 and a plurality of electrodes 32 disposed on the top surface 31; facing the second surface 12 of the post-like metal material 10 to the top surface 31 of the printed circuit board 30, and electrically connecting one end of each conductor 21 to the corresponding electrode 32; providing at least one light-emitting diode 40 with electrodes 41, and attaching the light-emitting diodes 40 on the first surface 11 of the post-like metal material 10; providing a plurality of wires 50, wherein one end of each wire 50 is electrically connected to the electrode 41 of the corresponding light-emitting diode 40, and the other end of the wire 50 is electrically connected the end of the corresponding conductor 21 that is not connected to the electrode 32 of the printed circuit board 30; providing an encapsulating material 60 for packaging. The encapsulating material 60 mainly encapsulates the first surface 11 of the post-like metal material 10, and shall covers at least the top end 211 of each conductor 21, the light-emitting diodes 40, and the wires 50. Phosphors 70 can also be disposed around the light-emitting diodes 40 or doped into the encapsulating material 60.
In addition, concerning the method of integrating the post-like metal material 10, the conductors 21, and the insulators 20, the conductors 21 can be encapsulated with the insulators 20 first, and then the conductors 21 and the insulators 20 are inserted into the through holes 13 of the post-like metal material 10 as a whole. The second method is to dispose the conductors 21 and the insulators 20 separately into the through holes 13 of the post-like metal material 10, wherein the insulators 20 can be powdered and located between the conductors 21 and the post-like metal material 10. Then, the conductors 21, the insulators 22, and the post-like metal material 10 can be combined together through a high-temperature sintering process.
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As stated above, the present invention packages the light-emitting diode 40 directly on the post-like metal material 10 to achieve a design of light-emitting device 1 with high heat-dissipating efficiency and high stability.
In addition, the electrodes 32 of the printed circuit board 30 is located below the post-like metal material 10, such that the electrode 41 of each light-emitting diode 40 can be electrically connected to the corresponding electrode 32 on the printed circuit board 30 via the corresponding conductor 21 in the post-like metal material 10, so as to decrease the overall area of the light-emitting device 1 and increase its application range.
Moreover, each light emitting device 40 of the light-emitting device 1 is collocated with two conductors 21, wherein one of the conductors 21 transmits an electrical signal, and the other transmits a ground signal. In other words, the ground signal is not transmitted by the post-like metal material 10. Therefore, thus the electrical short between the post-like metal material 10 and other conductors can be prevented.
Furthermore, the light-emitting device 1 can be incorporated with an existing lamp holder 9, wherein the light-emitting device 1 of LED can be directly adopted for illumination without replacing any present lamp.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the present invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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96145693 | Nov 2007 | TW | national |