Multi-package white LED device
Disclosed is a white LED device using a multi-package. The white LED device maximizes the efficiency of a green LED in the yellow gap to minimize a deviation in performance between the other color chips, in comparison with conventional white LED devices using RGB multi-chips. In addition, deviations in temperature, current and droop characteristics between the chips can be minimized, contributing to the simplification of a driving circuit. Therefore, the white LED device is suitable for commercialization. Furthermore, the white LED device has a higher color rendering index (R a ) (>80) than conventional white LED devices having single-package structures. The correlated color temperatures of the white LED device are controllable in the range of 2,700 to 12,000 K. The white LED device can express abundant colors for emotion lighting and can emit white light with high efficiency.
1. A multi-package white LED device comprising a plurality of single-color LED packages from which light beams are irradiated and mixed to achieve white light emission wherein at least one package of the plurality of single-color LED packages comprises: a blue light source; a phosphor disposed on the blue light source to absorb blue light emitted from the blue light source and emit light in the wavelength range of 500 to 700 nm; and a long-wavelength pass filter disposed on the phosphor to reflect blue light and transmit light in the wavelength range of 500 to 700 nm,
wherein the long-wavelength pass filter has a layer stack including first thin films and second thin films laminated alternately and repeatedly, the second thin films having a refractive index higher than that of the first thin films, and
wherein the long-wavelength pass filter includes third thin films as an uppermost layer and a lowermost layer with at least one of the uppermost layer and the lowermost layer having an optical thickness corresponding to 1/80 to 1/4.4 of the peak wavelength of the reflection band of the blue light source.
2. The multi-package white LED device according to claim 1 , wherein the light in the wavelength range of 500 to 700 nm is amber, yellow, green or red light.
3. The multi-package white LED device according to claim 1 , wherein the phosphor is a yellow, amber, green or red phosphor.
4. The multi-package white LED device according to claim 1 , wherein each of the first thin films and the second thin films constituting the layer stack formed between the uppermost layer and the lowermost layer has an optical thickness corresponding to ⅓ to ⅕ of the peak wavelength of the reflection band of the blue light source.
5. The multi-package white LED device according to claim 1 , wherein the first thin films are adjacent to the third thin films.
6. The multi-package white LED device according to claim 1 , wherein at least one of the uppermost layer and the lowermost layer has an optical thickness corresponding to 1/7 to 1/9 of the peak wavelength of the reflection band of the blue light source.
7. The multi-package white LED device according to claim 1 , wherein the number of the single-color LED packages is two or more.
8. The multi-package white LED device according to claim 1 , wherein the plurality of single-color LED packages comprises a) a combination of a red phosphor-converted single-color LED, a green phosphor-converted single-color LED, and a blue LED, b) a combination of a red LED, a green phosphor-converted single-color LED, and a blue LED, c) a combination of a red phosphor-converted single-color LED, an amber phosphor-converted single-color LED, a green phosphor-converted single-color LED, and a blue LED, d) a combination of a red LED, an amber phosphor-converted single-color LED, a green phosphor-converted single-color LED, and a blue LED, e) a combination of a red phosphor-converted single-color LED, a yellow phosphor-converted single-color LED, a green phosphor-converted single-color LED, and a blue LED, f) a combination of a red LED, a yellow phosphor-converted single-color LED, a green phosphor-converted single-color LED, and a blue LED, g) a combination of a yellow-based phosphor-converted white LED, a red phosphor-converted single-color LED, an amber phosphor-converted single-color LED, and a green phosphor-converted single-color LED, or h) a combination of a yellow-based phosphor-converted white LED, a red phosphor-converted single-color LED, and a green phosphor-converted single-color LED.
9. The multi-package white LED device according to claim 1 , wherein the plurality of single-color LED packages comprises a) a combination of a yellow phosphor-converted single-color LED and a blue LED, b) a combination of a green-based phosphor-converted bluish green LED and an amber phosphor-converted single-color LED, or c) a combination of a green-based phosphor-converted bluish green LED and a red phosphor-converted single-color LED.
10. The multi-package white LED device according to claim 1 , wherein the multi-package white LED device is part of a LED lamp.
11. The multi-package white LED device according to claim 1 , wherein the multi-package white LED device is part of a blacklight unit for a display.