1. Technical Field
The present disclosure relates to a light-emitting diode (LED) and a method for manufacturing the LED.
2. Description of Related Art
LEDs have been widely promoted as a light source of electronic devices owing to many advantages, such as high luminosity, low operational voltage and low power consumption. In practice, the LED generally includes a base, two electrodes located on the base, a light-emitting chip electrically connected with the two electrodes, and an encapsulation sealing the electrodes and the light-emitting chip. The electrodes are made of metal which has good thermal conductivity, whereby the electrodes can take away part of the heat generated by the light-emitting chip. However, the electrodes each have a limited area, whereby the heat dissipating efficiency of the LED by the electrodes is not good enough.
Therefore, an LED and a method for manufacturing the LED capable of overcoming the above described shortcoming is desired.
Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Embodiment of the present LED and the method for making the LED will now be described in detail below and with reference to the drawings.
Referring to
The base 10 is a rectangular plate and made of electrically insulating material, such as plastic or silicone. Two spaced protrusions 11 extend from a top surface of the base 10, and each of the protrusions 11 has an E-shaped configuration as viewed from a top of the base 10. The two protrusions 11 are arranged in mirror symmetry. The two electrodes 20 are located on top surfaces of the two protrusions 11, respectively. Each electrode 20 has a configuration matching that of the corresponding protrusion 11. A remaining part of the top surface of the base 10 without the protrusions 11 is lower than the top surfaces of the protrusions 11, and the thermal conductivity layer 30 is located on the remaining part of the top surface of the base 10. A height difference between the top surface of each protrusion 11 and the top surface of the base 10 is greater than twice the thickness of the thermal conductivity layer 30, so the electrode 20 located on the top surface of each protrusion 11 is apart and electrically insulated from the thermal conductivity layer 30.
A shape of each electrode 20 is the same as the corresponding protrusion 11 of the base 10. That is to say, each electrode 20 also has an E-shaped configuration as viewed from the top of the base 10, so each electrode 20 entirely covers the top surface of the corresponding protrusion 11. Each electrode 20 includes a connection portion 21 and three branches 22 extending from one side of the connection portion 21. The two connection portion 21 of the two electrodes 20 are adjacent to each other, in order to be electrically connected with two electrical contacts of the light-emitting chip 40. The branches 22 of the two electrodes 20 are extending along opposite directions from the two connection portions 21, respectively. The electrodes 20 and the thermal conductivity layer 30 are made of the same metal material, such as copper or aluminum.
The two electrical contacts of the light-emitting chip 40 are electrically connected to the two electrodes 20, respectively, by soldering, wherein soldering balls are formed on the two electrical contacts of the light-emitting chip 40, which are melted to connect with the two electrodes 20 by surface mounting technology. Alternatively, the light-emitting chip 40 can also be electrically connected to the two electrodes 20 by wire boding or eutectic bonding.
The encapsulation 50 is substantially cuboid-shaped, covers the light-emitting chip 40, the two electrodes 20 and the thermal conductivity layer 30, and seals the light-emitting chip 40 therein. The encapsulation 50 is made of heat-resistant and translucent material, such as plexiglass or epoxy resin. The free ends of the branches 22 of the two electrodes 20 extend outward from opposite sides of the encapsulation 50 to electrically with an external circuit structure (not shown) thereby to obtain external power for driving the light-emitting chip 40. The peripheral portion of the thermal conductivity layer 30 is uncovered by the encapsulation 50 and exposed to air, thus facilitating dissipation of heat from the thermal conductivity layer 30 to air.
In the LED 100, the top surface of the base 10 facing to the light-emitting chip 40 is entirely covered by the electrodes 20 and the thermal conductivity layer 30; therefore, the heat generated by the LED 100 can be efficiently transferred to outside via the electrodes 20 and the thermal conductivity layer 30, whereby the heat dissipating efficiency of the LED 100 is improved.
Referring to
The LED 100 can be manufactured in following steps.
As shown in
A metal sheet 70 is provided on the substrate 60, such as a copper or an aluminum sheet, and the metal sheet 70 entirely covers the top surface 61 of the substrate 60.
As shown in
As shown in
As shown in
A light-emitting chip 40 is provided on the base 10. The light-emitting chip 40 is electrically connected to the two electrodes 20 by flip chip bonding, with two electrical contacts formed on a bottom surface of the light-emitting chip 40 being soldered to the two electrodes 20, respectively.
An encapsulation 50 is formed on the light-emitting chip 40. The encapsulation 50 covers the top surface of the thermal conductivity layer 30 and seals the light-emitting chip 40 and the electrodes 20. In this embodiment, the bottom surface of the encapsulation 50 facing the light-emitting chip 40 defines a receiving groove 51 for receiving the light-emitting chip 40, the electrodes 20 and the protrusions 11 therein. The encapsulation 50 is made of heat-resistant and translucent material, such as plexiglass or epoxy resin. The encapsulation 50 can be formed in advance and then adhered to the top surface of the base 10. Alternatively, the encapsulation 50 can be injection molded onto the top surface of the base 10. In addition, a phosphor (not shown) can be mixed in the encapsulation 50 to obtain a desired color of light of the LED 100.
In the process, the electrodes 20 are formed on the base 10 by the way of stamping without using any chemical, thereby avoiding environment pollution. Further, the remaining part of the metal sheet 70 besides the electrodes 20 is utilized to constitute the thermal conductivity layer 30, thereby avoiding material waste and improving the heat dissipating efficiency of the LED 100.
The shapes of the electrodes 20 and the protrusions 11 of the base 10 can be adjusted by changing the shapes of the grooves 82 of the stamping mold 80. Referring to
In the previous embodiments, the two electrodes 20, 20a each have a flat structure. Referring to
Particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.
Number | Date | Country | Kind |
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101111049 | Mar 2012 | TW | national |