Patent ID: 8454203

Claim:
A discharge lamp unit comprising: a discharge lamp radiating light, inducing radiant heat; a supporting member supporting the discharge lamp; a circuit board supplying power to the discharge lamp being supported by the supporting member to allow the discharge lamp to radiate light; a casing member that holds the circuit board therein and holds the supporting member to be exposed outside of the casing member; a thermal absorption protect section being formed on a surface of the casing member on a side on which the supporting member is exposed, to allow the casing member to inhibit absorption of the radiant heat induced by the discharge lamp; a heat-radiation section formed on at least a portion of a surface of the casing member excluding the surface on the side on which the supporting member is exposed, the heat-radiation section facilitating radiation of heat in the casing member to the outside of the casing member; and a heat-insulating material disposed on a surface of the supporting member to be faced towards the circuit board, a dividing wall disposed between the supporting member and the circuit board in the space within the casing member, the dividing wall dividing the space on a plane perpendicular to a light axis direction of the discharge lamp, wherein the casing member is configured by a first casing member including the surface on the side on which the supporting member is exposed being mated with a second casing member not including the surface on the side on which the supporting member is exposed, and the thermal absorption protect section is formed on a surface of the first casing member, and the heat-radiation section is formed on a surface of the second casing member, and the thermal absorption protect section is configured such that a heat-insulating layer made of a material having a lower thermal conductivity than the casing member and a reflective layer forming a mirrored surface are laminated in order from the casing member side.