Lighting device with light modulation for white light

• US 8,348,457 B2
• Filed: 11/25/2009
• Issued: 01/08/2013
• Est. Priority Date: 11/25/2008
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Citizen Electronics Company Limited
• Inventors: Kadotani, Norikazu, Fukasawa, Koichi
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US12/625,846
• Publication Number:
  US 20100134043A1
• Time in Patent Office: 1,140 Days
• Field of Search: 362/84, 362/230, 362/231, 362/260, 362/294, 362/373, 257/88, 257/89, 257/79, 257/102
• US Class Current: 362/231
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H05B 45/40 Details of LED load circuits

Abstract

In a lighting device, a first LED is formed by sealing a blue LED element by a first resin, the first resin having a first phosphor included in the first resin so as to raise a correlation color temperature of an emitted light color; and a second LED is formed by sealing a blue LED element by a second resin, the second resin having a second phosphor included in the second resin so as to lower a correlation color temperature of an emitted light color. The lighting device emits light from white light of a color having a first correlation color temperature to white light of a color having a second correlation color temperature, and the first correlation color temperature is higher than the second correlation color temperature. Consequently, various tones of white light can be more easily adjusted and controlled over a long period.

Claims

1. A lighting device, comprising:

a plurality of first light-emitting diodes each including a plurality of first blue light-emitting diode elements, a first resin sealing the plurality of blue light-emitting diode elements, a first phosphor included in the first resin to receive a part of blue light from the first blue light-emitting diode elements and emit first phosphor-converted light, the plurality of first light-emitting diodes each emitting a first white light that comprises blue light from the first blue light-emitting diode elements and first phosphor-converted light, and the first white light having a first correlation color temperature;

a plurality of second light-emitting diodes each including a plurality of second blue light-emitting diode elements, a second resin sealing the plurality of second blue light-emitting diode elements, a second phosphor included in the second resin to receive a part of blue light from the second blue light-emitting diode elements and emit second phosphor-converted light, the plurality of second light-emitting diodes each emitting a second white light that comprises blue light from the second blue light-emitting diode elements and second phosphor-converted light, the second white light having a second correlation color temperature;

a heat dissipation plate; and

the plurality of first light-emitting diodes and the plurality of second light-emitting diodes being provided in pairs with respect to each other,

one of the first light-emitting diodes and one of the second light-emitting diodes in one of the pairs being mounted on the heat dissipation plate as a combination light-emitting diode, and

the first correlation color temperature being higher than the second correlation color temperature.

2. The lighting device according to claim 1:

wherein a current supply to the first blue light-emitting diode elements and a current supply to the second blue light-emitting diode elements are controlled separately by a control circuit.

3. The lighting device according to claim 1:

wherein the first white light is white light of a daylight color, and

the second white light is white light of an electric light bulb color.

4. The lighting device according to claim 1:

wherein the first white light having the first correlation color temperature ranges around 6500K to 7000K, and

the second white light having the second correlation color temperature ranges around 2600K to 3000K.

5. The lighting device according to claim 1:

wherein the first phosphor is a yellow phosphor to receive blue light and emit yellow fluorescent light, and

the second phosphor is a red phosphor to receive blue light and emit red fluorescent light.