Eri Miyamoto

Novel diffraction grating light guide for LED backlight

In conventional LED backlight as that used in mobile liquid crystal displays (LCDs), typically the structure consists of a light guide, a diffusing sheet, prism sheets and so on. In this work we would like to propose a novel light guide where we have applied a special diffraction grating technology which provides a high performance with a thinner backlight. The special designed diffraction gratings on the light guide redirects incident light by diffraction to the front direction without the utilization of prism sheets. For testing the performance we made a diffraction grating light guide suited for a 2.4 inch backlight with 4 LEDs in a trial. As a result, the backlight that consisted of a diffraction grating light guide, with either a single or none prism sheet achieved equivalent performance to conventional backlights.