LIGHT EMITTING DEVICE AND ILLUMINATION APPARATUS

• US 20110222264A1
• Filed: 03/11/2011
• Published: 09/15/2011
• Est. Priority Date: 03/12/2010
• Status: Active Grant

• Current Assignee: Toshiba Lighting & Technology Corporation (Toshiba Corporation)
• Original Assignee: Toshiba Lighting & Technology Corporation (Toshiba Corporation)
• Inventors: Nishimura, Kiyoshi, Matsuda, Shuhei, Betsuda, Nobuhiko, Shibusawa, Soichi
• Granted Patent: US 8,820,950 B2
• Time in Patent Office: Days
• US Class Current: 362/84
• 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: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21S 8/026 intended to be recessed in a ceiling or like overhead structure, e.g. suspended ceiling
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• 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: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/06 Adjustment of display parameters
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• 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 33/48 characterised by the semiconductor body packages
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs

Abstract

According to one embodiment, a light emitting device which is attached to an illumination apparatus and radiates light having a correlated color temperature of 2900 to 3600K is provided. The light emitting device includes a substrate, blue light emitting LED elements and red light emitting LED elements mounted on the substrate, and a wavelength converting unit. The red light emitting LED elements have a luminous intensity of 0.2 to 2.5 times as large as that of the blue light emitting LED elements at normal use temperature in a state where the light emitting device is attached to the illumination apparatus. The wavelength converting unit is excited by light emitted from the blue light emitting LED elements and converts the light to light having a peak wavelength within a range of 500 to 600 nm.

Claims

1. A light emitting device which is attached to an illumination apparatus and radiates light having a correlated color temperature of 2400 to 3600K, the device comprising:

a substrate;

blue light emitting LED elements mounted on the substrate;

red light emitting LED elements which are mounted on the substrate and have a luminous intensity of 0.2 to 2.5 times as large as that of the blue light emitting LED elements at normal use temperature in a state where the light emitting device is attached to the illumination apparatus; and

a wavelength converting unit which is excited by light emitted from the blue light emitting LED elements and converts the light to light having a peak wavelength within a range of 500 to 600 nm.

2. The light emitting device according to claim 1, having series circuits in which the blue light emitting LED elements and the red light emitting LED element are connected in series.

3. The light emitting device according to claim 1, wherein the plurality of blue light emitting LED elements and the plurality of red light emitting LED elements are mounted on the substrate and arranged alternately.

4. An illumination apparatus comprising:

an apparatus body; and

the light emitting device according to claim 1 disposed on the apparatus body.