| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem of a conventional line light source that has sacrificed the efficiency of light because the light source employs LED chips with a spread directivity characteristic to take precedence of the uniformity over other characteristics. SOLUTION: In the line light source where LED chips of surface mount type are placed on a board in a line, each LED chip has a focusing function and a ratio of the arrangement interval of the LED chips to a distance from each LED chip to a lighted face is decided by the following equation denoting the directivity of the LED chips; L(θ)=L(0 deg.)=L(0 deg.)/(2*cos2θ), where L(θ) is the lightness at an angle θ and θ is an angle from a perpendicular drawn from the LED chip to an original face. |
