A platesetter may have an optical imaging head which includes a diffractive modulator having individually controlled ribbons associated with individual pixels imaged onto a printing plate. While a p-type region 22 of the Si photodiode 20 is disposed in a part on the rear face 21b side of an Si substrate 21, a p-type region 32 of the InGaAs photodiode 30 is disposed in a part on the front face 31a side of an InGaAs substrate 31. The bonding region includes a metal layer which covers the interconnect region.