Patent ID: 6629764
Filing Date: 2003-10-07
Classification: G02B

Abstract:
An illuminator comprising:a light source; a light guide having first and second side faces, the first side face having a thickness greater than a thickness of the second side face, the light guide having a horizontal upper surface and a bottom surface slanting toward the upper surface, wherein said light source is located adjacent the first side face; a reflector for reflecting light from said light source towards said first side face; a reflection sheet located adjacent the bottom surface of said light guide; and a light diffusion plate located on the upper surface of said light guide, wherein: the bottom surface comprises a plurality of groove groups extending substantially in parallel to said first side face and a plurality of flat faces connecting adjacent groove groups of said plurality of groove groups, a depth and a width of a constituent groove in each of said plurality of groove groups gradually increasing from said first side face towards the second side face, a pitch of the groove groups defined a sum of a width of the constituent grooves in each of said plurality of groove groups and a width of the flat face in said each groove group, the sum being constant throughout a distance from said first side face to said second side face of said light guide; adjacent groove groups of said plurality of groove groups are separated by a flat face, wherein widths of successive ones of said respective flat faces increase in a direction toward said first side face; widths of successive groove groups of said plurality of groove groups decrease in a direction toward said first side face.