| 摘要 |
PROBLEM TO BE SOLVED: To improve the use efficiency of light from a reflection mirror without decreasing the optical characteristics by constituting a side wall part so as to seal the side hole of a concave reflection mirror and to control a light- emitting region. SOLUTION: The light source device for image projection consists of a concave reflection mirror 7 having a spherical, ellipsoidal or parabolic reflection face, a discharge lamp 1 with a small electrode gap assembled in the concave reflection mirror 7, and a side wall part 9 attached to the open end of the concave reflection mirror 7. The side wall part 9 is formed to seal the side holes 8 of the concave reflection mirror 7 and to control the light-emitting region. Thereby, leaking of light from the reflection mirror 7 or decrease in the accuracy of the reflection face can be prevented, and irregularity in a dichroic reflection film formed on the reflection face can be avoided. Thus, decrease in the optical characteristics is prevented and the use efficiency of light can be improved. Moreover, a front cover can be easily attached without decreasing the optical characteristics and scattering of the broken discharge lamp when the lamp is broken can be prevented.
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