Title:
面状照明装置
Document Type and Number:
Japanese Patent JP4874875
Kind Code:
B2
Abstract:
The absolute value of the light amount is increased by providing main light sources (28) and auxiliary light sources (29) on four sides of a light guide plate (30) having a flat and rectangular light exit plane (30a) and a pair of rear planes (30b,30c) being formed on a side opposite from said light exit plane and inclined such that a thickness of said light guide plate in a direction perpendicular to said light exit plane grows thicker with an increasing distance from each of a pair of opposite light entrance planes (30d,30e) and joining each other in a middle between said pair of opposite light entrance planes; whereas the amounts of light emitted by LED chips (50) of the main light sources and the auxiliary light sources are adjusted such that illuminance is highest near the central area of the light guide plate to obtain a high-in-the-middle, bell-curve illuminance distribution for light emitted by the light guide plate. A planar lighting device achieving a reduced thickness and weight and capable of emitting an increased amount of illumination light is provided.
Inventors:
Osamu Iwasaki
Application Number:
JP2007151527A
Publication Date:
February 15, 2012
Filing Date:
June 07, 2007
Export Citation:
Assignee:
FUJIFILM Corporation
International Classes:
F21S2/00; F21Y101/02
Domestic Patent References:
| JP2004079488A | ||||
| JP11162234A | ||||
| JP9045121A |
Foreign References:
| WO2007020966A1 |
Attorney, Agent or Firm:
Nozomi Watanabe
Haruko Sanwa
Haruko Sanwa