Patent Application
20130119415
This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 100141242 filed in Taiwan, R.O.C. on Nov. 11, 2011, the entire contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a light emitting diode (LED) structure, in particular to an white-light LED structure diode capable of converting some of the light source with a wavelength of 400 nm˜500 nm into a light with a wavelength of 490 nm˜600 nm without affecting the light emission efficiency of the LED with a wavelength of 600 nm˜700 nm, and uniformly mixing the lights with different wavelengths to enhance the light mixing effect.
2. Description of the Related Art
In recent years, blue-light LED plus yellow phosphor package has become a mainstream of backlight source of white-light LED, but most yellow phosphor related patents are owned by a Japanese company, Nichia, and LED of these patents have a lower color rendering index, and the white-light LED produced by mixing blue light, red light and green light gains increasingly higher market share.
In present technologies, one or more chip packages can be installed on the same LED as disclosed in U.S. Pat. No. 6,577,073, wherein red-light and blue-light LEDs are installed on the same frame and covered with phosphor, so that after the phosphor is excited by blue light, a green light is emitted, and the green light is mixed with the red light and the blue-light to form a white-light dot light source. However, the red light has relatively lower light emission efficiency and blocked by the phosphor, so that the LED has lower light emission efficiency. Therefore, the LED structural design as disclosed in R.O.C. Pat. No. M380580, but such package structure comes with a complicated process, which is not favorable in mass production.
In view of the aforementioned shortcomings, the present invention provides a simple structure for facilitating the manufacture of LED package structures, and achieves the effects of enhancing the light mixing effect and the light emission efficiency, and providing a white-light dot light source of a higher color rending index.
Therefore, it is a primary objective of the present invention to provide an LED package structure, wherein phosphor is coated onto specific areas to improve the effects of exciting and converting light energy, reducing the probability of blocking lights of other wavelengths, and enhancing the overall light emission performance.
To achieve the foregoing objective, the present invention provides an LED package structure for enhancing a mixed light effect, comprising: at least one first light emitting chip, for providing a light source with a wavelength of 400 nm˜500 nm; at least one second light emitting chip, for providing light source with a wavelength of 600 nm˜700 nm; a frame structure, for containing and installing the first light emitting chip and the second light emitting chip, so that the lights passing through the first light emitting chip and the second light emitting chip are mixed to form a white-light dot light source, and the frame structure includes: a first containing portion, being a downwardly tapered cup structure for installing the first light emitting chip; a second containing portion, being a downwardly tapered cup structure for installing the second light emitting chip; a spacing portion, disposed between the first containing portion and the second containing portion, for bonding, connecting and installing the first light emitting chip and the second light emitting chip, for forming a white-light dot light source after the lights emitted from the first light emitting chip and the second light emitting chip are mixed in the light mixing area; a first colloid, doped with a green-light phosphor, and filled into the first containing portion, for encapsulating the first light emitting chip, such that after some of the light source emitted by the first light emitting chip is excited by the green-light phosphor, the light source changes its wavelength of 400 nm˜500 nm to a wavelength of 490 nm˜600 nm; a second colloid, filled into the second containing portion, for covering the second light emitting chip; and an encapsulating colloid, packaged and filled into the light mixing area, and disposed on the first colloid and the second colloid.
In view of the directional range of the exit light, the first containing portion and the second containing portion can be designed with a downwardly tapered trapezoid shape. To improve the light mixing and light emitting effects, the first containing portion and the second containing portion can be designed with a downwardly tapered trapezoid shape, and a bottom angle of the trapezoid shape not adjacent to the spacing portion is a right angle.
Wherein, the green-light phosphor of the first colloid is doped on a surface of the first light emitting chip and totally covered onto the first light emitting chip to achieve the light conversion effect and provide lights with different wavelengths to enhance the color rendering performance.
Wherein, the second colloid is doped with a dispersant to provide a more uniform light and avoid blocking the green-light phosphor. To achieve the uniform mixed light effect, the encapsulating colloid is doped with a dispersant, such that after the lights with different wavelengths are mixed uniformly, a white-light dot light source is produced.
To enhance the light efficiency and the light mixing effect and achieve the easy manufacture, the LED package structure for enhancing mixed light effect of the present invention comprises: at least one first light emitting chip, for providing a light source with a wavelength of 400 nm˜500 nm; at least one second light emitting chip, for providing a light source with a wavelength of 600 nm˜700 nm; a frame structure, for containing and installing the first light emitting chip and the second light emitting chip, such that after lights emitted from the first light emitting chip and the second light emitting chip are mixed, a white-light dot light source for emitting light is formed, and the frame structure comprising: a first containing portion, being a downwardly tapered cup structure, and having a circular arc shaped cross-section, and the first containing portion for installing the first light emitting chip; a second containing portion, disposed adjacent to the first containing portion, and being a downwardly tapered cup structure and having a circular arc shaped cross-section, for installing the second light emitting chip; and a light mixing area, for forming a white-light dot light source after the lights emitted from the first light emitting chip and the second light emitting chip are mixed in the light mixing area; a first colloid, doped with a green-light phosphor, and filled into the first containing portion, for covering the first light emitting chip, such that after some of the light source emitted from the first light emitting chip is excited by the green-light phosphor, the light source changes its wavelength of 400 nm˜500 nm to a wavelength of 490 nm˜600 nm; a second colloid, filled into the second containing portion, for covering the second light emitting chip; and an encapsulating colloid, packaged and filled into the light mixing area and disposed on the first colloid and the second colloid.
Wherein, the second colloid is doped with a dispersant to produce a more uniform light, and the encapsulating colloid is doped with a dispersant to enhance the light mixing effect.
In the design of the present invention, the phosphor is doped at the top of the light source with the wavelength of 400 nm˜500 nm only, so that the light energy absorption of the phosphor can change the light to a light with a wavelength of 490 nm˜600 nm to increase the range of the wavelength covered by the exiting light, so as to enhance the light rendering performance of the white-light LED, and an exiting light with another wavelength will not be blocked by the phosphor cause a drop of the light emission efficiency, and thus the invention can overcome the drawbacks of the prior art. In addition, the shape of the frame in accordance with the present invention are designed for placing two different LED chips with different wavelengths separately and the dispensing and phosphor coating processes are simple to facilitate mass production.
The technical content of the present invention will become apparent by the detailed description of the following embodiments and the illustration of related drawings as follows.
With reference to
The first containing portion 140 and the second containing portion 142 have a light mixing area 144 disposed above, and packaged and filled with an encapsulating colloid 164 and situated on the first colloid 160 and the second colloid 162. Since the density of the green-light phosphor 180 doped in the first colloid 160 is adjusted according to an optical design, therefore the light entering from the first containing portion 140 into the light mixing area 144 includes the first light L1 and the third light L3 having two different wavelengths in the ranges of 400 nm˜500 nm and 490 nm˜600 nm respectively, while a second light L2 having a wavelength of 600 nm˜700 nm emitted from the second light emitting chip 12 also enters from the second containing portion 142 into the light mixing area 144, and these lights having three different wavelengths are mixed in the light mixing area 144 to achieve the effect of emitting white light. To enhance the light mixing effect, the encapsulating colloid 164 is doped with a dispersant 182, so that the light entering into the light mixing area 144 will produce optical reactions of diffusion and scattering to provide a more uniformly mixed light for the applications such as backlight and illumination by a white-light light source.
The white-light LED package structure 1 of the present invention is more applicable for two other methods of coating phosphor. Besides the uniform distribution method of uniformly doping in the first colloid 160, a remote phosphor coating method or a conformal coating method can be adopted to dope the green-light phosphor 180 into the first colloid 160. With reference to
With reference to
With reference to
In summation of the description above, the present invention has the following advantages:
1. The phosphor is arranged above the light source for exciting the phosphor, not only achieving the effect of converting the light energy into lights of different wavelengths, but also avoiding blocking the light of other light sources to improve the color rendering index of the white light and achieve the effects of enhancing light emission efficiency, and saving power consumption.
2. A containing groove is provided for containing the LED chip, and each containing groove is dispensed and coated with phosphor, which can be mass produced easily to simplify the complicated manufacturing process and improve the low yield rate of the prior art.
3. An optical design based on the shape of the frame is adopted to improve the light mixing effect and provide a white-light LED with the features of higher color rendering index, better uniformity and lower power consumption.
| Number | Date | Country | Kind |
|---|---|---|---|
| 100141242 | Nov 2011 | TW | national |
