Light source device and projection-type display apparatus

A light source device comprising:

• a blue laser light source;
• a green laser light source;
• a red laser light source;
• a first retardation plate that controls polarization of blue laser light emitted from the blue laser light source;
• a polarizing beam splitter that separates the blue laser light whose polarization is controlled by the first retardation plate into a first blue laser light and a second blue laser light;
• a second retardation plate that controls polarization of the second blue laser light separated by the polarizing beam splitter;
• a fluorescent plate that is excited by the first blue laser light separated by the polarizing beam splitter and emits fluorescent light including a green component and a red component;
• a first dichroic mirror that combines the second blue laser light whose polarization is controlled by the second retardation plate, green laser light emitted from the green laser light source, and red laser light emitted from the red laser light source, to generate combined laser light;
• a dynamic diffuser plate that diffuses the combined laser light combined by the first dichroic mirror to generate diffused laser light;
• and
• a second dichroic mirror that combines the diffused laser light diffused by the dynamic diffuser plate and the fluorescent light emitted from the fluorescent plate.