Patent ID: 7108399

Claim:
A light source unit comprising: a substrate formed of a material having high heat conductivity; a light emitting diode (LED) group comprising a plurality of light emitting diodes mounted on the substrate for irradiating beam to an object; a chip resistor group comprising a plurality of chip resistors mounted on said substrate in the same direction as said LED group; a light emission controlling circuit for supplying power for light emission to the LED group so as to heat said substrate with heat generated simultaneously with light emission from said LED group; a heat generation controlling circuit for supplying power for heat generation to said chip resistor group so as to heat the substrate with heat generated in said chip resistor group; temperature determining means in the form of a chip mounted on said substrate for determining a temperature of said substrate; and a control unit for determining the amount of power to be supplied for light emission to said LED group by said light emission controlling circuit and for determining the amount of power to be supplied for heat generation to said chip resistor group by said heat generation controlling circuit; wherein said control unit comprises a warm-up controlling unit for warming up said LED group, and a light source controlling unit for enabling said LED group to scan said object; and wherein said warm-up controlling unit operable to provide a command to supply the maximum power for light emission said light emission controlling circuit and is operable to provide command to supply the maximum power for heat generation until the temperature of the substrate as determined by said temperature determining means reaches a predeterminined threshold.