Patent ID: 7714956
Filing Date: 2010-05-11
Classification: G02B,G02F

Abstract:
1. A front-illuminating device comprising: a light source; and a light-directing body that is placed in front of an object to be illuminated, the light-directing body having an incident surface on which light from the light source is made incident, a first light-releasing surface from which light is released to the object to be illuminated and a second light-releasing surface, placed face to face with the first light-releasing surface, for releasing light reflected from the object to be illuminated, wherein the object to be illuminated is a reflection-type liquid crystal element, wherein the second light-releasing surface is formed into a stepped shape having slanting portions for reflecting light mainly from the light source toward the first light-releasing surface and flat portions for transmitting light reflected mainly from the object to be illuminated are alternately placed, and an optical means, which suppresses light from the slanting portions on the second light-releasing surface of the light-directing body from being reflected by the first light-releasing surface, is placed on the first light-releasing surface, wherein the second light-releasing surface is formed so as to include N steps (N>1), each step including one flat portion and one slanting portion and having a width (Wi) and wherein the width of each step is such as to satisfy the following relationship: