| 摘要 |
<p>A projection type display device which prevents light from a dichroic prism (910) constituting color synthesis means of an optical system, etc., from entering the back side of a liquid crystal light valve. The dichroic prism (910) comprises four triangular prisms having an equal refractive index, and a glass filter (912) for absorbing and cutting off a blue luminous flux is bonded to the incidence surface (910R) of a red luminous flux. After passing through each light valve (925), a modulated luminous flux of each color passes through a prism unit, is reflected by its X-shaped reflection surface and is directed toward the projection lens unit 6. At this time, part of the blue luminous flux may not be reflected by the reflection surface but incident on the back of the red light valve (925R). Light leaking from the prism in this way is absorbed and cut off by the filter (912). Accordingly, it is possible to prevent the erroneous operation of the liquid crystal light valve due to the entrance of light from the back surface.</p> |
