| 摘要 |
An image projection apparatus has three cathode ray tubes for respectively generating images of red, green and blue light, two dichroic mirrors each reflecting any one among the red, green and blue images and allowing the remaining images to be passed through them to combine the three colour images, and a lens unit enlarging and projecting the combined image to a large-sized screen. Two of the CRTs are arranged to be symmetrical to each other with respect to the optical axis of the third CRT, so as to form an angle of less than 180 deg. between the optical axes of the other two CRTs. The two dichroic mirrors are arranged with respect to one another and the CRTs to allow the incident angle of incoming light to be less than 45 deg. respectively, relative to lines normal to the two mirrors, respectively, to increse the reflectance of the mirrors. Both incident angles of the incoming light from the two cathode ray tubes to the two dichroic mirrors is 37.5 degrees. Loss of light is reduced by increasing reflectance of both mirrors.
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