OPTICAL CONVERSION ELEMENT AND LIQUID CRYSTAL DISPLAY

摘要

PROBLEM TO BE SOLVED: To provide a practical optical element which has a function to convert a line light source or a point light source into a surface light source and relatively reduces light emitted to an oblique and frontward direction or controls the quantity thereof. SOLUTION: The optical conversion element 4 with a sheet like shape converts the linear light source into the surface light source by making light from the line light source incident from an end face, making it be reflected inside and making it be emitted form a front face 42. A number of prism parts 45 to reflect incident light are formed on a rear face. The angle θ which two slopes of each of the prism parts 45 form with each other is <=90 deg.. The tip of the top part which the two slopes of each of the prism parts 45 form with each other is a flat surface or a curved surface with >=0.1 μm and <=5 μm width. The pitch of each of the prism parts 45 is >=50 μm and <=300 μm and the depth d of each of the prism parts 45 is equal to or less than 10% of the total thickness t.