Control of Laser Speckle Noise Using Liquid Crystal Devices

Abstract

A laser is a light source because of its high efficiency and brightness with low power consumption and long lifetime, pure color and extremely wide color expression that can be realized by choosing the wavelength of laser light, and high directivity and small etendue of light which contribute to downsizing. These characteristics are strong merits, especially for a projection display system. However, there are serious problems in utilizing a laser as a light source. But laser beam is coherent light, strong interference occurs between laser light and the surface topography of objects such the screen. This is well known as “speckle noise”. Therefore, the suppression of speckle noise is necessary for laser displays such as these in an image projection system. In this study, in order to reduce the speckle noise, we used liquid crystal devices that have electrically controllable optical characteristics and manufactured a lot of LC cells.