Light source device and projection type display apparatus

A light source device for a projection display apparatus, comprising:

• a phosphor;
• an excitation light source configured to output excitation light for exciting the phosphor;
• a surface-curved dichroic mirror having a curved surface and being configured to cause one of the excitation light from the excitation light source and fluorescence from the phosphor to pass through the curved surface and to cause the other of the excitation light and the fluorescence to be reflected along an optical path which is different from an optical path of the one of the excitation light and the fluorescence after passage through the curved surface;
• and
• a converging lens formed separately from the surface-curved dichroic mirror and positioned between the surface-curved dichroic mirror and the phosphor,
• wherein the surface-curved dichroic mirror is configured to cause the one of the excitation light and the fluorescence after passage through the curved surface, neither to substantially converge, nor to substantially diverge, but converge the other of the excitation light and the fluorescence that is reflected, on a direction which is different from a direction of the optical path of the one of the excitation light and the fluorescence after passage through the curved surface.