Patent ID: 7378630

Claim:
A light emitting unit which radiates auxiliary light to a subject to be imaged, said light emitting unit comprising: a plurality of light emitting elements disposed so as to have radiation areas different from each other, said light emitting elements being electrically connected in series; and a changing device which changes the number of light emitting elements in a light emitting state in said light emitting elements, wherein said changing device comprises a plurality of switching circuits provided in parallel with each other, one end of each of said plurality of switching circuits being connected to the light emitting elements at a predetermined position in the plurality of light emitting elements connected in series, and wherein, when a constant voltage is applied to one end of each of said plurality of switching circuits, said plurality of switching circuits substantially maintain the amount of current flowing through said light emitting elements regardless of the number of the light emitting elements in the light emitting state, wherein said plurality of switching circuits respectively have voltage dividing resistors for substantially maintaining the amount of current flowing through said light emitting elements regardless of the number of the light emitting elements in the light emitting state, the voltage dividing resistors differing in resistance value from each other.