FLAT LIGHTING DEVICE

• Main Author: AKAOKA HIROKI
• Format: Patent
• Language: English
• Published: 16.08.2002
• Edition: 7
• Subjects: BLASTING; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HEATING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21Sand F21V, RELATING TO THEFORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THELIGHT EMITTED; LIGHTING; MECHANICAL ENGINEERING; NON-PORTABLE LIGHTING DEVICES; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; SYSTEMS THEREOF; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ARTCOLLECTIONS [XRACs] AND DIGESTS; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLEEXTERIORS; WEAPONS

PROBLEM TO BE SOLVED: To provide a flat lighting device having an image plane with uniform brightness at its whole part. SOLUTION: Light reflection pattern 29 of a transparent base board 2 is formed so as to have a prescribed angle of inclination θ to the light axis direction. A light source part 5, composed of a light guide body 3 and point light sources 4a, 4b arranged at both end parts of the light guide body, close to one side surface 8 of the transparent base board 2. A light path conversion means 12 composed of a groove part 15 and a flat part 16 are formed at one side surface 10 of the light guide body 3. The groove part 15 is formed so that the farther the distance from the point light source at one side becomes, the deeper the depth of the groove becomes, and after passing through the deepest groove part formed at a prescribed position, the groove part is formed so that the nearer the distance from the point light source at the other side becomes, the shallower the depth of the groove becomes. The deepest groove part is formed at the position shifted from the central position of the light guide body toward either one of the point light source with an arbitrary distance. By the above, the distribution of the light going out from the light guide body 3 toward the transparent base board 2 can be changed, and unevenness of the brightness on an image plane is improved.