Optical device and protector

An optical device comprising:

• a plurality of optical modulators for respectively modulating a plurality of color lights according to image information;
• a color-combining optical device for combining and irradiating the respective color lights modulated by the optical modulators;
• a base made of heat-conductive material and fixed to at least either one of a pair of faces crossing with a light-incident face of the color-combining optical device;
• an optical conversion plate arranged on the downstream of the each optical modulator, the optical conversion plate having:
• an optical conversion film for converting an optical property of a light beam irradiated from the optical modulator;
• and a transparent member made of heat-conductive material on which the optical conversion film is attached;
• and
• a retaining plate made of heat-conductive material for supporting and fixing the optical conversion plate, the retaining plate having an opening for allowing the light beam to pass therethrough,
• wherein the retaining plate is fixed to a lateral face of the base,
• wherein at least two said optical conversion plates are provided as a first optical conversion plate and a second optical conversion plate,
• wherein the retaining plate includes:
• a plate member supporting and fixing the first optical conversion plate at the periphery of the opening;
• and a protrusion protruding from the plate member toward an out-of-plane direction and supporting and fixing the second optical conversion plate,
• wherein the plate member has a bonding portion attached to the lateral face of the base and a support portion supporting and fixing the first optical conversion plate, and
• wherein the support portion is recessed relative to the bonding portion toward a protruding direction of the protrusion.