| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem associated with lowered luminance on the periphery of a diffusion plate due to color irregularity compared with the luminance on the center portion. <P>SOLUTION: In the direct LCD backlight constructed by mounting light emitting diodes (LEDs) 2 on the upper face of an insulating printed circuit board 1, surrounding a circumference of side faces of the LEDs 2 with a frame member 3, and arranging a diffusion plate 4 on the upper face of the frame member 3 and opposite to the LEDs 2, a color tone equivalent to that on the center portion is obtained on the outer peripheral portion by making pitches of arrangement of the LEDs 2 narrower on the outer peripheral portion (P1) of the printed circuit board 1 than those on the center portion (P3), wherein the LEDs 2 consists of a light source of three primary colors red (R), green (G), and blue (B). The color irregularity and the lowering of luminance on the outer peripheral portion are prevented. Since the LED mounting area is made equivalent to the effective display area, space-saving is achieved, and reduction in the number of mounted LEDs can be expected with respect to the effective display area. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
