Patent ID: 8817388

Claim:
An imaging device equipped with a photodetector, the imaging device comprising: a first lens having a positive or negative refractive power; a second lens having a positive or negative refractive power and including an object side which is concave; a third lens having a positive or negative refractive power and including an object side and an imaging side which are both aspherical; and a fourth lens having a positive or negative refractive power and including an object side and an imaging side which are both aspherical, wherein the first lens to the fourth lens are arranged in sequence from an object, and the imaging device meets Conditional Expression 1 to Conditional Expression 3: 0.25 <FBL/f< 0.35 [Conditional Expression 1] 3.5 <OL/FBL< 4.5 [Conditional Expression 2] f/D≦ 2.6 [Conditional Expression 3] where FBL denotes a distance from a last imaging side to a photodetector of a device part in the imaging device, OL denotes a distance from the object side of the first lens to the photodetector with reference to an optical axis, f denotes a focal length of the imaging device with reference to the optical axis, and D denotes an aperture of an entrance pupil of the imaging device.