In order to supply design rules for brightness viewing angle of liquid crystal display

this paper presents the detailed study of brightness viewing angle of side-type backlight unit. We consider that three reasons may have influence on the brightness viewing angle

which is type of light source entering light guide plate

type of light guide plate and collocation of optical film. First

short side entering type and long side entering type were studied; Second

different type of light guide plate

ink printed

injection and roll stamping light guide plate were studied; Last

different collocation of optical film were studied. Test data shows one half brightness viewing angle in horizontal direction of different entering type is about 50 under the same type of light guide plate and collocation of optical film

but short side entering type has different brightness distribution in horizontal direction. One half brightness viewing angle in horizontal direction of different light guide plate is about 50 under the same entering type and collocation of optical film

and brightness distribution in horizontal direction is almost same. The minimum value of one half brightness viewing angle is 27

maximal value is 82 under the same entering type and light guide plate. Our study shows the main factor of brightness viewing angle is collocation of optical film

secondary factor is type of light source entering the light guide plate

and different type of light guide plate has no influence on brightness viewing angle.