LED illumination device

• US 20100244061A1
• Filed: 03/25/2010
• Published: 09/30/2010
• Est. Priority Date: 03/26/2009
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Electric Works Company Limited (Panasonic Holdings Corporation)
• Inventors: Shirakawa, Tomoki, Matsubayashi, Yoko
• Granted Patent: US 8,455,887 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• 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 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: 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

An LED illumination device includes: a substrate; one or more red LED chips arranged on the substrate; a plurality of blue LED chips arranged on the substrate; and a plurality of third-color LED chips arranged on the substrate. Respective centers of the red LED chips are arranged on a circumference of a first circle having as its center a point on the substrate, respective centers of the blue LED chips being arranged on the circumference of a second circle concentric with and greater than the first circle, respective centers of the third-color LED chips being arranged in a region between the first circle and the second circle.

Claims

1. An LED illumination device comprising:

a substrate;

one or more red LED chips arranged on the substrate;

a plurality of blue LED chips arranged on the substrate; and

a plurality of third-color LED chips arranged on the substrate,

wherein respective centers of the red LED chips are arranged on a circumference of a first circle having as its center a point on the substrate, respective centers of the blue LED chips being arranged on the circumference of a second circle concentric with and greater than the first circle, respective centers of the third-color LED chips being arranged in a region between the first circle and the second circle.

2. The LED illumination device of claim 1, further comprising bell-shaped sealing portions for independently covering the red, blue and third-color LED chips, wherein curvatures of the sealing portions near the intersecting points between surfaces of the sealing portions and optical axes of the red, blue and third-color LED chips are set so that the sealing portions covering the blue LED chips have a smaller curvature than that of the sealing portions covering the red LED chips.

3. The LED illumination device of claim 1, further comprising a bell-shaped sealing portion for covering all the red, blue and third-color LED chips, the sealing portion including a light diffusion agent, concentration of the light diffusion agent being greater in a peripheral region of the first circle than in a region near the center of the first circle.

4. The LED illumination device of claim 1, further comprising a light diffusion member arranged at a light irradiation side of the red, blue and third-color LED chips, the light diffusion member having greater diffuseness in a peripheral region of the first circle than in a region near the center of the first circle.

5. The LED illumination device of claim 1, further comprising a reflection plate arranged at a light emission side of the red, blue and third-color LED chips, the reflection plate having a bell-shaped inner surface, curvature of the surface of the reflection plate at the intersecting points between the reflection plate and light emission surfaces of the red, blue and third-color LED chips being set so that the curvature of the surface of reflection plate around the blue LED chips becomes smaller than that around the red LED chips.