| 摘要 |
PROBLEM TO BE SOLVED: To separate color and combine color with high accuracy and project an image with high image quality, by applying a wavelength selective reflecting film to one of two faces forming a prism vertical angle, and arranging a plurality of dichroic prisms with specified prism vertical angles mutually opposedly so that the wavelength selective reflecting films form a cross. SOLUTION: Each of dichronic prisms 11-14 has a wavelength selective reflecting film applied to one of two faces forming each of prism vertical anglesθ11-θ14 of isosceles triangular prisms. The prism vertical anglesθ11-θ14 of the prisms 11-14 are to be less than 90 deg., for instance, 89 deg.-90 deg., so that a clearance is not generated when the ridgelines forming four prism vertical angles intersect, and the wavelength selective reflecting film applied faces and non-applied faces of the prisms 11-14 are mutually opposedly arranged so that the wavelength selective reflecting films 11R, 13R reflecting red light and the wavelength selective reflecting films 12B, 14B reflecting blue light are orthogonal in a cross shape, and are fixed to each other with an adhesive.
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