Numerous advantages of field emission cathodes of carbon materials such as reliability, high efficiency, long lifetime, and short switching time make them great candidates for vacuum electronics applications such as light sources, LCD backlights, and many others. However, because of field emission features of carbon emitters there exists an unevenness of light distribution on the phosphor screen in cathodoluminescent light sources. One of the methods of improving the light uniformity is the application of holographic light shaping diffusers. In the present work we have investigated a possibility to improve a brightness distribution in the cathodoluminescent light source with a carbon fiber cathode applying various holographic diffusers. (C) 2003 American Vacuum Society.