This application claims the benefit of Taiwan application Serial No. 97141686, filed Oct. 29, 2008, the subject matter of which is incorporated herein by reference.
1. Field of the Invention
The invention relates in general to a precipitating method and a light emitting diode and an apparatus using the same, and more particularly to a centrifugal precipitating method and a light emitting diode and an apparatus using the same.
2. Description of the Related Art
At present, the light emitting diode (LED) has a wide range of application including sign board, traffic signs, or the backlight source of a display device. Generally speaking, the LED manufacturing process is basically divided into the steps of chip bonding, wire bonding, adhesive dispensing, and packaging. The chip bonding step is for fixing the chip in several bowl-shaped recesses of a frame. The wire bonding step is for soldering wire onto the chip for being electrically connected to the chip. The adhesive dispensing step is for injecting colloid into the bowl-shaped recess for covering the chip. The packaging step is for dividing and packaging the LEDs accomplished on the frame.
The adhesive dispensing step is further divided into several sub-steps, such as the steps of mixing glue and fluorescent powder to obtain a colloid, deaeration, injecting the colloid into bowl-shaped recess, deaeration again, precipitating and baking the fluorescent powder. The sub-step of precipitating the fluorescent powder is one of the important factors affecting the light emitting effect of the LED and the uniformity of light and color distribution. Currently, there are two methods of precipitating the fluorescent powder, namely, heating and depositing the colloid. The two methods are disclosed below.
In the method of heating the colloid, the glue becomes thinner after being heated. As the specific gravity of the fluorescent powder is relatively greater than that of the glue, the fluorescent powder suspended in the colloid will be deposited at the bottom. Thus, the fluorescent powder will be precipitated on the bottom of the bowl-shaped recess due to the difference between the specific gravities of the fluorescent powder and the glue. However, not all types of glue can have a specific gravity which is significantly different from that of the fluorescent powder when being heated. As such, it is possible that the fluorescent powder can not be precipitated on the bottom of the bowl-shaped recess successfully.
According to the deposition method, the fluorescent powder is gradually precipitated on the bottom of the recess by the gravity. However, whether the fluorescent powder is capable of being precipitated on the bottom of the recess is determined according to the time period for deposition, the concentration of glue, and the specific gravity of the fluorescent powder. Thus, the time cost for manufacturing LED is increased, and the overall productivity of LED is decreased accordingly.
Thus, under the requirement of high efficiency, it is an imminent issue for the manufacturers to provide a method and apparatus capable of precipitating the fluorescent powder on the bottom of the recess and whereby increasing both of the light emitting effect and quality of LED.
The invention is directed to a centrifugal precipitating method and a light emitting diode (LED) and an apparatus using the same. A lighting structure is rotated so as to provide a centrifugal force thereto, and the fluorescent particles of the colloid are moved toward a bottom surface of the recess, whereby achieve the effect of efficiently precipitating the fluorescent particles. In an embodiment, the particle diameter of the fluorescent particles is preferably but non-limitedly less than 30 μm. According to the disclosure, the surface of the colloid in the lighting structure becomes even while the bubbles that are formed by the air in the colloid are also discharged. Thus, the light emitting effect, conformity rate and quality of the LED are correspondingly increased.
According to a first aspect of the present invention, a centrifugal precipitating method is provided. The method includes the following steps. A lighting structure is provided. The lighting structure includes a frame, a chip and a colloid. The frame has a recess. The chip is disposed on a bottom surface of the recess. The colloid includes a glue and several fluorescent particles. The glue is filled in the recess and covers the chip. The fluorescent particles are distributed in the glue. Then, the lighting structure is rotated to move the fluorescent particles toward the bottom surface of the recess.
According to a second aspect of the present invention, an LED including a frame, a chip and a colloid is provided. The frame has a recess. The chip is disposed on a bottom surface of the recess. The colloid includes a glue and several fluorescent particles. The glue is filled in the recess and covers the chip. The fluorescent particles are distributed in the glue by way of covering the bottom surface of the recess and the light output surface of the chip.
According to a third aspect of the present invention, a centrifugal precipitating apparatus used in a lighting structure is provided. The lighting structure includes a frame, a chip and a colloid. The frame has a recess. The chip is disposed on a bottom surface of the recess. The colloid includes a glue and several fluorescent particles. The glue is filled in the recess and covers the chip. The fluorescent particles are distributed in the glue. The centrifugal precipitating apparatus includes a rotation apparatus and a fixing mechanism. The rotation apparatus rotates the lighting structure, so that the fluorescent particles are moved toward the bottom surface of the recess. The fixing mechanism is disposed on the rotation apparatus for fixing the lighting structure.
The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
The embodiment of this invention provides a centrifugal precipitating method. The method includes the following steps. Firstly, a lighting structure is provided. The lighting structure includes a frame, a chip and a colloid. The frame has a recess. The chip is disposed on a bottom surface of the recess. The colloid includes a glue and several fluorescent particles. The glue is filled in the recess and covers the chip. The fluorescent particles are distributed in the glue. Next, the lighting structure is rotated to move the fluorescent particles toward the bottom surface of the recess.
Two embodiments are disclosed below for elaborating a centrifugal precipitating method and a light emitting diode (LED) and apparatus using the same. However, anyone who is skilled in the art of the invention will understand that the drawings and disclosure are for elaboration only, and are intended to limit the invention.
The present embodiment of the invention is exemplified by performing the centrifugal precipitating method on the lighting structure 10 in
The centrifugal precipitating apparatus 200 in
The disposition and functions of the circuit elements in the centrifugal precipitating apparatus 200 are illustrated as follows. The centrifugal precipitating apparatus 200 includes a rotation apparatus 210 and a fixing mechanism 220. The rotation apparatus 210 has an accommodation recess 211 for rotation. In the present embodiment of the invention, the fixing mechanism 220, for example, is implemented by several engaging members, which are located on an inner wall 211s of the accommodation recess 211 for fixing the lighting structure by way of engaging. The structure and type of the fixing mechanism 220 are not limited to the above exemplification, and any mechanisms capable of fixing the lighting structure on the inner wall 211s of the accommodation recess 211 can also be used in the present embodiment of the invention.
The centrifugal precipitating method of
Next, the method proceeds to step 303, the lighting structure 10 is fixed on an inner wall 211s of the accommodation recess 211 of the rotation apparatus 210 by the fixing mechanism 220. Preferably, the colloid 130 of the lighting structure 10 is disposed to face the rotation axis Y of the accommodation recess 211. In general, when the colloid 130 of the lighting structure 10 is disposed to face the rotation axis Y of the accommodation recess 211 (i.e., the colloid 130 is vertically disposed on the lighting structure 10), the colloid 130 may disperse outside the recess 111 due to gravity. Thus, the present embodiment of the invention may adjust the dimensions of the recess 111 and the pre-precipitated LED 100 so as to avoid the colloid 130 dispersing outside the recess 111. In the present embodiment of the invention, the length and width of the recess 111 are adjusted to be smaller than 50 mm, and the length and width of the pre-precipitated LED 100 are adjusted to be smaller than 7 mm. It is only an exemplification of the present embodiment of the invention to avoid the colloid 130 dispersing outside the recess 111 by adjusting the dimensions of the recess 111 and the pre-precipitated LED 100. In other exemplification, it is also practicable to avoid the colloid 130 dispersing outside the recess 111 by driving the pre-precipitated LED 100 to swing or by appropriately selecting the glue 131 of the colloid 130 and its co-operated mechanism, which can be referred to the second embodiment for further description. Besides, because the pre-precipitated LEDs 100 of the lighting structure 10 are arranged along a direction D, the lighting structure 10 is preferably fixed on the inner wall 211s with the direction D being parallel to the rotation axis Y of the accommodation recess 211, whereby the centrifugal force can be evenly provided to the pre-precipitated LEDs 100.
Then, the method proceeds to step 305, the lighting structure 10 is driven to rotate by the accommodation recess 211 of the rotation apparatus 210 which is rotated. That is, when the accommodation recess 211 is driven at a rotation speed of 3000 rpm (revolutions per minute) for example, the accommodation recess 211 being rotated drives the lighting structure 10 to rotate through the fixing mechanism 220. Because the frame 110 of the lighting structure 10 is a flexible structure, the lighting structure 10 being driven turns into a condition as being attached on the inner wall 211s of the accommodation recess 211 due to the centrifugal force. Besides, as the lighting structure 10 is fixed with its colloid facing the rotation axis Y of the accommodation recess 211, the fluorescent particles P of the colloid 130 of each pre-precipitated LED 100 are moved toward the bottom surface 111s of the recess 111 by the centrifugal force generated during rotation, whereby the fluorescent particles P of the colloid 130 are distributed in a manner illustrated in
As indicated in
In addiction, when the LED is disposed on the backlight module as a light source, the axial light intensity of the LED is preferably close to the luminous flux measured by an integrating sphere when the LED is disposed on the backlight module, so that the LED has an even light color distribution when being disposed on the backlight module.
In
In
In generally, the white light of the LED is achieved by exciting the materials in the fluorescent particles with the light emitted by the chip. As indicated in
In
In
This embodiment differs with the first embodiment in the design of the cartridge, the heater and the fixing mechanism of a centrifugal precipitating apparatus. Similar or identical components in the embodiment are labeled with similar or identical reference numbers and repetitive descriptions are not repeated here. Besides, the present embodiment of the invention is again taken the pre-precipitated LED 100 of the lighting structure 10 in
The cartridge 230′ is for receiving and fixing several lighting structures 10 as indicated in
The heater 240′ is for increasing the temperature at each lighting structure 10. In the present embodiment of the invention, the temperature at each lighting structure 10 is correspondingly increased as the temperature at the cavity of the accommodation recess 211′ is increased. The glue 131 of the colloid 130 of the present embodiment of the invention can be implemented by a thermosetting material. As such, when the heater 240′ increases the temperature at the cavity of the accommodation recess 211′ and correspondingly increases the temperature at each lighting structure 10, the surface of the glue 131 of each lighting structure 10 is temporarily solidified. Therefore, this embodiment can reduce the likelihood that the colloid 130 filled in the recess 111 may disperse outside when the lighting structure 10 is vertically disposed. The heater 240′ can also be disposed on the inside of the centrifugal precipitating apparatus 200 as indicated in
According to the present embodiment of the invention, the fixing mechanism 220′ is swingably disposed on the accommodation recess 211′ of the rotation apparatus 210′ for fixing and driving each lighting structure 10 to swing along a first direction D1. Thus, the colloid 130 can be evenly distributed in the recess 111, and can be avoided from being dispersing outside the recess 111 when each lighting structure 10 is vertically disposed.
Corresponding to the designs of the cartridge 230′, the heater 240′ and the fixing mechanism 220′ of the centrifugal precipitating apparatus 200′, the centrifugal precipitating method of the present embodiment of the invention includes steps 301, 303′ and 305 as indicated in
The method begins at step 301, several lighting structures 10 as indicated in
Next, the method proceeds to step 303′ which includes steps 303a and 303b for fixing the lighting structure 10 on the rotation apparatus 210′. In step 303a, several lighting structures 10 are disposed in the cartridge 230′. Next, in step 303b, the fixing mechanism 220′ is used for fixing the cartridge 230′ on an inner wall 211s of the accommodation recess 211′ of the rotation apparatus 210.
The accommodation recess 211′ of the present embodiment of the invention has, for example, a diameter of 100 cm. In step 305, the accommodation recess 211′ is rotated at, for example, a rotation speed of 1500 rpm, so that the lighting structure 10 is driven to rotate through the fixing mechanism 220′ and the cartridge 230′. As the lighting structure 10 is fixed in the cartridge 230′ with its colloid facing the rotation axis Y of the accommodation recess 211′, the fluorescent particles P of the colloid 130 of each pre-precipitated LED 100 are moved toward the bottom surface 111s of the recess 111 by the centrifugal force generated during rotation, whereby the fluorescent particles P of the colloid 130 are distributed in a manner illustrated in
In the centrifugal precipitating method of the present embodiment of the invention, the step 305 is further executed by using the heater 240′ to increase the temperature in the cavity of the accommodation recess 211′, so as to heat each lighting structure 10. Thus, the surface of the glue 131 is solidified to avoid the colloid 130 dispersing outside the recess 111. Besides, in step 305, each lighting structure 10 can be driven to swing along a first direction D1 of
According to the second embodiment of the invention, more lighting structures 10 can be processed at the same time through the use of a cartridge 230′, hence having the advantage of increasing productivity in addition to the advantages disclosed in the first embodiment. Besides, the disposition of the heater 240′ and the swingable design of the fixing mechanism 220′ can avoid the colloid 130 from being dispersed outside the recess 111.
According to the centrifugal precipitating method and LED and apparatus using the same disclosed in the above embodiments of the invention, a centrifugal force is provided to the lighting structure so that the fluorescent particles of the colloid are moved toward a bottom surface of the recess. Therefore, the fluorescent particles can quickly precipitate on the light output surface of the chip and on the bottom surface of the recess. Besides, the surface of the colloid in the lighting structure is even while the air stored in the colloid is also discharged. Thus, the light emitting effect, conformity rate, and quality of the LED are correspondingly increased. Moreover, with the application of the cartridge, productivity is further increased in an above-mentioned embodiment.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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097141686 | Oct 2008 | TW | national |