Patent Application
20140268637
This application claims the priority benefit of Taiwan application serial no. 102109082, filed on Mar. 14, 2013. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Invention
The invention relates to a wavelength converting structure and a manufacturing method thereof. Particularly, the invention relates to a wavelength converting structure adapted to a light-emitting diode (LED) chip and a manufacturing method thereof
2. Description of Related Art
Since a light-emitting diode (LED) has advantages of long lifespan, small volume, high shock resistance, low heat generation and low power consumption, etc., it is widely used as indicators or light sources in home appliance and various apparatuses. In recent years, the LED is developed towards a trend of multi-color and high brightness, and an application field thereof has been extended to large-scale outdoor billboards, traffic light and related fields. In the future, the LED may even become a main illumination light source having both power saving and environmental friendly features.
Regarding a manufacturing method of a conventional LED package structure, the LED chip is first disposed on a base, and then a fluorescent layer is formed on the LED chip through a mold filling method. However, the fluorescent layer formed through the mold filling method is easy to produce bubbles therein, which influences a refractive index of the fluorescent layer and an appearance thereof. Moreover, by using the mold filling method, the fluorescent layer directly contacts the LED chip, and a wavelength converting efficiency of the fluorescent layer is attenuated under heat, which leads to problems of brightness decrease and color shift of the whole LED package structure. Moreover, by using the mold filling method, the amount of the fluorescent adhesive and position of the fluorescent powder at a junction of the base and the fluorescent layer cannot be controlled.
The invention is directed to a wavelength converting structure, which has a better device characteristic.
The invention is directed to a method for manufacturing a wavelength converting structure, which is used to manufacture the aforementioned wavelength converting structure.
The invention provides a wavelength converting structure, which is adapted to cover a carrier carrying at least one light-emitting diode (LED) chip. The wavelength converting structure includes a base film and a fluorescent layer. The base film has a first bending portion and a first flat portion connected to the first bending portion. The first flat portion is disposed on the carrier, and an accommodating space is defined by the first bending portion and the carrier. The LED chip is disposed in the accommodating space. The fluorescent layer is disposed on the base film and has a second bending portion and a second flat portion connected to the second bending portion. The second bending portion is conformal to the first bending portion, and the second flat portion is conformal to the first flat portion.
In an embodiment of the invention, a gap exists between the first bending portion of the base film and the LED chip.
In an embodiment of the invention, the gap is an air gap or a vacuum gap.
In an embodiment of the invention, the first bending portion is an arc structure.
In an embodiment of the invention, the first bending portion has a roof portion and a sidewall portion connected to the roof portion, the roof portion is parallel to the first flat portion, and the sidewall portion is perpendicular to the first flat portion.
In an embodiment of the invention, a material of the base film includes polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC) or polyurethane (PU).
In an embodiment of the invention, the fluorescent layer includes an adhesive and a fluorescent powder. The fluorescent powder includes a red fluorescent powder, a blue fluorescent powder, a yellow fluorescent powder, a green fluorescent powder or a combination thereof.
In an embodiment of the invention, the first bending portion includes a first sub-bending portion and a second sub-bending portion. The first sub-bending portion and the second sub-bending portion have a seamless connection therebetween and have a first recessed region. The second bending portion includes a third sub-bending portion and a fourth sub-bending portion. The third sub-bending portion and the fourth sub-bending portion have a seamless connection therebetween and have a second recessed region. The third sub-bending portion and the fourth sub-bending portion are respectively conformal to the first sub-bending portion and the second sub-bending portion. The second recessed region is disposed corresponding to the first recessed region, and the LED chip is disposed corresponding to the first recessed region.
The invention provides a method for manufacturing a wavelength converting structure, which includes following steps. A base film is provided, and the base film has an upper surface and a lower surface opposite to each other. A fluorescent layer is formed on the upper surface of the base film. The base film and the fluorescent layer are disposed in a mold to perform a thermocompression bonding process, such that the base film has a first bending portion and a first flat portion connected to the first bending portion, and the fluorescent layer has a second bending portion and a second flat portion connected to the second bending portion. The second bending portion is conformal to the first bending portion, and the second flat portion is conformal to the first flat portion. The mold is removed.
In an embodiment of the invention, the step of disposing the base film and the fluorescent layer into the mold to perform the thermocompression bonding process includes following steps. The mold including a male mold and a female mold is provided, where the lower surface of the base film contacts the male mold, and the fluorescent layer contacts the female mold. The thermocompression bonding process is performed on the mold, the base film and the fluorescent layer to deform the base film and the fluorescent layer through the mold.
In an embodiment of the invention, the method for manufacturing the wavelength converting structure further comprises performing a cooling process on the mold, the deformed base film and the deformed fluorescent layer after the thermocompression bonding process is performed and before the mold is removed.
According to the above descriptions, since the fluorescent layer of the wavelength converting structure of the invention has the design of the bending portion, and the base film is conformal to the fluorescent layer, when the wavelength converting structure covers the LED chip on the carrier, the wavelength converting structure does not directly contact the LED chip. In this way, the wavelength converting structure is not attenuated under heat, and has better device characteristic.
In order to make the aforementioned and other features and advantages of the invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
As shown in
Moreover, a material of the base film 110a includes polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polyurethane (PU), silicone or epoxy. Further, the base film 110a must have a high light transmittance and a low material deformation degree in order to form a high quality wavelength converting structure. Preferably, the material of the base film 110a includes polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC) or polyurethane (PU). The fluorescent layer 120a is composed of an adhesive 126a and a fluorescent powder 128a, where the fluorescent powder 128a includes a red fluorescent powder, a blue fluorescent powder, a yellow fluorescent powder, a green fluorescent powder or a combination thereof, which is not limited by the invention. Moreover, the fluorescent layer 120a of the present embodiment is directly adhered on the base film 110a, and is fixed on the carrier 10 through the base film 110a. A part of light emitted from the LED chip 20 can penetrate through the base film 110a to excite the fluorescent powder 128a in the fluorescent layer 120a to generate an excitation light, another part of light emitted from the LED chip 20 can directly penetrate through the base film 110a and the adhesive of the fluorescent layer 120a to produce a mixing light, for example, a white light with the excitation light.
Referring to
The fluorescent layer 120c of the present embodiment is disposed on the base film 110c, and the second bending portion 122c thereof includes a third sub-bending portion 122c1 and a fourth sub-bending portion 122c2. The third sub-bending portion 122c1 and the fourth sub-bending portion 122c2 have a seamless connection therebetween, i.e. are fondled integrally, and have a second recessed region C2. The second flat portion 124c is connected to edges of the third sub-bending portion 122c1 and the fourth sub-bending portion 122c2. Particularly, the third sub-bending portion 122c1 and the fourth sub-bending portion 122c2 of the second bending portion 120c are respectively conformal to the first sub-bending portion 112c1 and the second sub-bending portion 112c2 of the first bending portion 110c, and a position of the second recessed region C2 corresponds to a position of the first recessed region C1.
Since the fluorescent layer 120c of the wavelength converting structure 100c of the present embodiment has the second recessed region C2, after the light emitted from the LED chip 20 passes through the fluorescent layer 120c, an irradiation angle θa thereof can be increased to about 160 degrees. Namely, the irradiation light shape of the whole light-emitting device (including the carrier 10, the LED chip 20 and the wavelength converting structure 100c) has a wide angle. In this way, the light-emitting device complies with a light shape specification of a streetlight.
Only the structures of the wavelength converting structures 100a and 100b of the invention are introduced above, and the method for manufacturing the wavelength converting structures 100a and 100b is not introduced. Accordingly, the method for manufacturing the wavelength converting structure 100a is described in a following embodiment, and the wavelength converting structure 100a with the bending portion of an arc structure is taken as an example for description, and the method for manufacturing the wavelength converting structure 100a is described in detail below with reference of
Then, referring to
Then, referring to
In detail, referring to
Then, a cooling process can be performed on the mold M and the deformed base film 110a and the fluorescent layer 120a, so as to cure the base film 110a and the fluorescent layer 120a. Finally, referring to
Since the wavelength converting structure 100a of the present embodiment is manufactured through the mold M based on the thermocompression bonding process, none bubble is generated during the manufacturing process of the wavelength converting structure 100a compared to the conventional technique of forming the fluorescent layer through a mold filling method, such that the conventional problems that the bubbles influence the refractive index of the fluorescent layer and spoil an appearance thereof are avoided. Moreover, in the present embodiment, the fluorescent layer 120a is first evenly coated on the upper surface 111a of the base film 110a, and then the thermocompression bonding process is performed by using the mold M to form the bending portion (the first bending portion 112a and the second bending portion 122a) and the flat portion (the first flat portion 114a and the second flat portion 124a). Therefore, the problem that the amount of the fluorescent adhesive and position of the fluorescent powder at a junction of the base and the fluorescent layer cannot be controlled by using the conventional mold filling method is avoided. Moreover since the wavelength converting structure 100a is manufactured by using the mold M according to the thermocompression bonding process, a thickness and an appearance of the wavelength converting structure 100a can be changed by adjusting a distance and shapes of the male mold M1 and the female mold M2.
In summary, since the fluorescent layer of the wavelength converting structure of the invention has the design of the bending portion, and the base film is conformal to the fluorescent layer, when the wavelength converting structure covers the LED chip on the carrier, the wavelength converting structure does not directly contact the LED chip. In this way, the wavelength converting structure is not attenuated under heat, and has better device characteristic. Moreover, since the wavelength converting structure is manufactured through the mold according to the thermocompression bonding process, none bubble is generated during the manufacturing process, and the wavelength converting structure may have better device characteristic and appearance. Moreover, a thickness and the appearance of the wavelength converting structure can be changed through the mold, by which manufacturing flexibility of the wavelength converting structure is improved.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102109082 | Mar 2013 | TW | national |
