This application claims the priority benefit of Taiwan application serial no. 95116888, filed on May 12, 2006. All disclosure of the Taiwan application is incorporated herein by reference.
1. Field of Invention
The present invention relates to a light emitting device and a wavelength converting material thereof. More particularly, the present invention relates to a light emitting device with high brightness and a wavelength converting material thereof.
2. Description of Related Art
The yellow phosphor encapsulant 130 is directly overlaid on the blue LED chip 120 and is located in the illumination range of the blue light. The yellow phosphor encapsulant 130 includes a transparent material 132 and yellow phosphors 134, wherein the yellow phosphors 134 are uniformly mixed in the transparent material 132 and is suitable for being activated by the blue light emitted by the blue LED chip 120 so as to emit a yellow light. The LED 100 can be used as a white light source after the blue light and yellow light therein are appropriately mixed.
Additionally, in the conventional art, in order to uniformly mix the blue light and yellow light in the LED 100, a scatter or air bubbles with light insensitivity and preferable reflectivity are doped in the yellow phosphor encapsulant 130 and are uniformly mixed with the yellow phosphors 134. However, this process consumes a part of the quantity of light and decreases the brightness of the LED 100.
Accordingly, an objective of the present invention is to provide a wavelength converting material with high wavelength converting efficiency.
Another objective of the present invention is to provide an LED with high brightness.
The wavelength converting material provided by the present invention includes a wavelength converting activator and a scatter. The wavelength converting activator is suitable for being activated by a light with a wavelength λ1 so as to emit a light with a wavelength λ2. The scatter is disposed on the wavelength converting activator. The scatter is suitable for scattering the light irradiated to a surface thereof.
According to the wavelength converting material described in an embodiment of the present invention, the material of the wavelength converting activator is selected from fluorescent material, phosphorous material, dyes, and any combination thereof. The composition of the wavelength converting activator is represented by, for example: (A)2x(B)2y(C)2z(D)3x+sy+tz:(E), wherein 0≦x≦15, 0≦y≦9, 0≦z≦4; s is the valence number of Component B; t is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Ni, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof.
According to the wavelength converting material described in an embodiment of the present invention, the material of the scatter is selected from, for example, Al2O3, ZnO, SiO2, TiO2, or the material with the composition of (A)2x′(B)2y′(C)2z′(D)3x′+s′y′+t′z′:(E), wherein 0≦x′≦15, 0≦y′≦9, 0≦z′≦4; s′ is the valence number of Component B; t′ is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Ni, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is Ce, Eu, Tb, Mn, and any combination thereof.
According to the wavelength converting material described in an embodiment of the present invention, the scatter is suitable for being activated by the light with the wavelength λ1 so as to emit a light with a wavelength λ3.
According to the wavelength converting material described in an embodiment of the present invention, the scatter is suitable for being activated by the light with the wavelength λ2 so as to emit a light with a wavelength λ3.
According to the wavelength converting material described in an embodiment of the present invention, a bonding compound is further included, which is disposed between the wavelength converting activator and the scatter. Furthermore, the bonding compound is suitable for being activated by the light with the wavelength λ1 so as to emit a light with a wavelength λ4.
According to the wavelength converting material described in an embodiment of the present invention, the wavelength converting activator includes a core and a first transparent coating. The core is suitable for being activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ2. The core is clad with the first transparent coating. The material of the core is selected from fluorescent material, phosphorous material, dyes, and any combination thereof. The composition of the core is represented by, for example: (A)2x(B)2y(C)2z(D)3x+sy+tz: (E) wherein 0≦x≦15, 0≦y≦9, 0≦z≦4; s is the valence number of Component B; t is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof, D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof.
According to the wavelength converting material described in an embodiment of the present invention, a second transparent coating is further included to clad the wavelength converting activator and the scatter, wherein the material of the second transparent coating is, for example, SiO2.
According to the wavelength converting material described in an embodiment of the present invention, the wavelength converting material further includes a transparent material, wherein the wavelength converting activator and the scatter are distributed in the transparent material.
The LED provided by the present invention includes a carrier, an LED chip, and a wavelength converting material. The LED chip is disposed on the carrier and electrically connected to the carrier, wherein the LED chip is suitable for emitting the light with the wavelength λ1. The wavelength converting material is disposed around the LED chip and includes a wavelength converting activator and a scatter. The wavelength converting activator is suitable for being activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ2. The scatter is disposed on the wavelength converting activator and suitable for scattering the light irradiated to a surface thereof.
According to the LED described in an embodiment of the present invention, the material of the wavelength converting activator is selected from fluorescent material, phosphorous material, dyes, and any combination thereof. The composition of the wavelength converting activator is represented by, for example, (A)2x(B)2y(C)2z(D)3x+sy+tz:(E), wherein 0≦x≦15, 0≦y≦9, 0≦z≦4; s is the valence number of Component B; t is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Ti, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof.
According to the LED described in an embodiment of the present invention, the material of the scatter is, for example, Al2O3, ZnO, SiO2, TiO2, or the material with the composition of (A)2x′(B)2y′(C)2z′(D)3x′+s′y′+t′z′:(E), wherein 0≦x′≦15, 0≦y′≦9, 0≦z′≦4; s′ is the valence number of Component B; t′ is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Ni, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof.
According to the LED described in an embodiment of the present invention, the scatter is suitable for being activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ3.
According to the LED described in an embodiment of the present invention, the scatter is suitable for being activated by the light with the wavelength λ2 so as to emit the light with the wavelength λ3.
According to the LED described in an embodiment of the present invention, a bonding compound is further included, which is disposed between the wavelength converting activator and the scatter. The bonding compound is suitable for being activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ4.
According to the LED described in an embodiment of the present invention, the wavelength converting activator includes a core and a first transparent coating. The core is suitable for being activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ2. The core is clad with the first transparent coating, wherein the material of the first transparent coating is, for example, SiO2. The material of the core is selected from fluorescent material, phosphorous material, dyes, and any combination thereof. The composition of the core is represented by, for example: (A)2x(B)2y(C)2z(D)3x+sy+l′z:(E), wherein 0≦x≦15, 0≦y≦9, 0≦z≦4; s is the valence number of Component B; t is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof.
Furthermore, the light refractive index of the transparent material is approximate to that of the first transparent coating, so as to avoid total reflection and F Fresnel loss at the junction of the first transparent coating and the transparent material when the light is irradiated into the transparent material from the first transparent coating.
According to the LED described in an embodiment of the present invention, a second transparent coating is further included to clad the wavelength converting activator and the scatter, wherein the second transparent coating is, for example, SiO2.
According to the LED described in an embodiment of the present invention, the wavelength converting material further includes a transparent material, wherein the wavelength converting activator and the scatter are distributed in the transparent material.
Since the scatters on the wavelength converting activators increase the gap of two wavelength converting activators adjacent to each other, the light with the wavelength λ1, activates the wavelength converting activators through the gap between the wavelength converting activators when the wavelength converting materials are irradiated by the light with the wavelength λ1. Therefore, these wavelength converting activators can be sufficiently activated so as to emit the light with the wavelengths λ2. As such, the brightness of a light emitting diode with the wavelength converting material is higher.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred 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.
The material of the scatter 320 is selected from, for example, Al2O3, ZnO, SiO2, TiO2, and any material capable of reflecting the light with the specific wavelength. The scatter 320 is physically or chemically bonded with the wavelength converting activator 310 and is disposed on the wavelength converting activator 310. It should be noted that the scatter 320 can be provided with only the function of reflecting a light in a specific wavelength range, or also can be with the functions of reflecting a light in a specific wavelength range and being activated by another light in another specific wavelength range at the same time. The material of such scatters 320 with dual-function is selected from, for example, Al2O3, ZnO, SiO2, TiO2, or the material with the composition of (A)2x′(B)2y′(C)2z′(D)3x′+s′y′+t′z′:(E), wherein 0≦x′≦15, 0≦y′≦9, 0≦z′≦4; s′ is the valence number of Component B; t′ is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is Mg, Ca, Sr, Ba, Zn, Cu, Ni, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof. It should be noted that at least one set of the numeral values from x′ and x, y′ and y, z′ and z, s′ and s, and t′ and t are different. That is, the component elements of the scatter 320 with dual-function can be the same as those of the wavelength converting activator 310, but the ratios of the compositions of them are different.
The scatter 320 is further activated by the light with the wavelength λ1 to emit a light with a wavelength λ3 and reflect the light with the wavelength λ2. Additionally, in another embodiment, the scatter 320 is also activated by the light with the wavelength λ2 to emit a light with the wavelength λ3 and reflect the light with the wavelength λ1. Definitely, in another embodiment of the present invention, a part of the scatter 320 is suitable for being activated by the light with the wavelength λ1 to emit the light with the wavelength λ3 and reflect the light with the wavelength λ2. The remaining part of the scatter 320 is suitable for being activated by the light with the wavelength λ2 to emit the light with the wavelength λ3 and reflect the light with the wavelength λ1.
When the scatter 320 is chemically bonded with the wavelength converting activator 310, a bonding compound 330 is located between the scatter 320 and the wavelength converting activator 310. The scatter 320 is suitable for scattering the light irradiated to the surface thereof.
It should be noted that since the amount of the bonding compound 330 generated depends on the conditions of bonding reaction, in addition to exposing a part of the surface of the wavelength converting activator 310 as shown in
Additionally, in addition to being in the form of particles, the wavelength converting material 300 can also be in the form of gel during manufacturing. Referring to
Furthermore, the wavelength converting activator can further include a core and a first transparent coating besides the fluorescent material, phosphorous material, dyes, and any combination thereof. The relative description will be described in detail below.
The material of the core 312 is selected from, for example, fluorescent material, phosphorous material, dyes, and any combination thereof. More particularly, the composition of the wavelength converting activator 310 is represented by, for example (A)2x(B)2y(C)2z(D)3x+sy+tz:(E), wherein 0≦x≦15, 0≦y≦9, 0≦z≦4; s is the valence number of Component B; t is the valence number of Component C; and A is selected from Y, Ce, Tb, Gd, Sc, Sm, Eu, Al, Ga, Tl, In, B, Lu, and any combination thereof; B is selected from Mg, Ca, Sr, Ba, Zn, Cu, Li, Na, K, Ag, and any combination thereof; C is selected from Mo, W, P, V, Si, Ti, Zr, Nb, Ta, and any combination thereof; D is selected from O, S, Se, and any combination thereof; and E is selected from Ce, Eu, Tb, Mn, and any combination thereof. The first transparent coating 314 is clad on the core 312, wherein the first transparent coating 314 is, for example, SiO2 or another transparent material. The scatter 320 is physically or chemically bonded with the first transparent coating 314.
Definitely, the wavelength converting material 301 of the present embodiment can further include a transparent material 340 as shown in
Additionally, in another embodiment of the present invention, the wavelength converting material can include a second transparent coating in addition to the first transparent coating. Referring to
Of course, the wavelength converting material 302 in the present embodiment can further include a transparent material as shown in
Based on the above, according to the present invention, the above wavelength converting material (such as the wavelength converting materials 300, 301, and 302) can be further applied in various light-emitting devices such as LEDs, field emission devices (FEDs), or other light-emitting devices. An LED is taken as an example for illustrating in detail below.
The wavelength converting material 300′ is disposed around the LED chip 520. Furthermore, the LED 500 in the present invention further includes a molding compound 540 disposed on the carrier 510, so as to seal the LED chip 520 and the wavelength converting material 300′ between the carrier 510 and the molding compound 540.
When the LED chip 520 emits the light with the wavelength λ1, a part of the light with the wavelength λ1 is directly irradiated to the wavelength converting activator 310. The remaining part of the light with the wavelength λ1 is irradiated to the scatter 320 and then irradiated to the wavelength converting activator 310 after being scattered by the scatter 320. Then, the wavelength converting activator 310 is activated by the light with the wavelength λ1 so as to emit the light with the wavelength λ2. As such, after the lights with the two wavelengths are mixed, the LED chip 520 can emit a color light with a specific color. For example, when λ1 is in the wavelength range of the blue light and λ2 is in the wavelength range of the yellow right, the LED chip 520 can emit white light.
Although the LED 500 with the wavelength converting material 300′ is taken as an example, in another embodiment of the present invention, the LED with the wavelength converting material 301 in the form of gel or with the wavelength converting material 302 can also be employed. It should be noted that when the LED employs the wavelength converting material 301 in the form of gel during manufacturing, in the present embodiment, the light refraction index of the transparent material can be adjusted to be approximate to that of the first transparent coating 314, so as to avoid total reflection and Fresnel loss at the junction of the first transparent coating 314 and the transparent material 340 when the light is irradiated into the transparent material 340 from the first transparent coating 314.
In view of the above, the LED and the wavelength converting material provided by the present invention have at least the following advantages.
1. Since the scatters are capable of scattering light irradiated to the surface thereof, the light with the wavelength λ1 emitted by the LED and the light with the wavelength λ2 emitted by the activated wavelength converting activators can be uniformly mixed.
2. Since the scatters on the wavelength converting activators can increase the gap between two adjacent wavelength converting activators, the wavelength converting activators can be sufficiently activated. Taking
3. When the LED has the wavelength converting material, since the wavelength converting activator can be activated more sufficiently, the brightness of the LED provided by the present invention is higher.
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 invention. In view of the foregoing, it is intended that the present invention is overlaid on modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
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