Patent ID: 8013683
Filing Date: 2011-09-06
Classification: H03L,H05K

Abstract:
1. A constant-temperature type crystal oscillator comprising: a crystal unit that is installed on one principal surface of a circuit substrate; and chip resistors, which function as heating elements, and which are installed on the other principal surface of the circuit substrate so as to face a principal surface of the crystal unit, the chip resistors heating up the crystal unit to keep an operational temperature of the crystal unit constant, wherein a heating metal film facing the principal surface of the crystal unit is provided on the one principal surface of the circuit substrate, wherein a heat conducting material is interposed between the principal surface of the crystal unit and the heating metal film to perform thermal coupling therebetween, wherein the heating metal film is thermally coupled to electrodes of the chip resistors via a plurality of electrode through holes, wherein the heating metal film includes a projecting portion, wherein a power transistor for supplying electric power to the chip resistors is disposed on the one principal surface of the circuit substrate, and wherein a collector of the power transistor is connected to the projecting portion of the heating metal film.