Patent ID: 8270103

Claim:
An imaging lens unit configured to be processed by a solder reflow process, comprising: a lens group consisting of one or more lenses; and a lens tube that supports the lens group, wherein the imaging lens unit comprises one or more cationically-cured epoxy resin lenses formed from a cationically-curable epoxy resin material, the lens tube is formed from a thermoplastic resin material having a deflection temperature under load of not lower than 200° C., and the imaging lens unit has a clearance between the lens tube and at least one of the cationically-cured epoxy resin lenses and has lens supporting portions that are provided at at least three locations inside the lens tube and that support the at least one cationically-cured epoxy resin lens, wherein the imaging lens unit has a clearance between the lens tube and the cationically-cured epoxy resin lens supported by the lens supporting portions, in a manner that satisfies the following formula (1): { L ×( T− 25)×α 2 −B ×( T− 25)×α 1 }×(1/2)≦ X (1) wherein B represents an inner diameter of the lens tube at an installation place of the cationically-cured epoxy resin lens at 25° C.; L represents a diameter of the cationically-cured epoxy resin lens at 25° C.; α 1 represents an average thermal expansion coefficient of the lens tube in a temperature range of from 25° C. to 260° C.; α 2 represents an average thermal expansion coefficient of the cationically-cured epoxy resin lens in the temperature range of from 25° C. to 260° C.; T represents the highest temperature (° C.) in the solder reflow process for the imaging lens unit; and X represents the clearance.