Patent ID: 8089325

Claim:
An oven controlled crystal oscillator comprising: a crystal vibrator with a crystal piece seal-enclosed therein and having external terminals; circuit elements of an oscillating stage that constitutes an oscillation output circuit together with the crystal vibrator, and of a buffering stage that buffer-amplifies output of said oscillating stage; circuit elements of a temperature control circuit that at least has a heater element that heats said crystal vibrator and a temperature sensor element that detects operating temperature of said crystal vibrator, and that maintains the operating temperature of said crystal vibrator at a constant temperature; a first circuit substrate having said crystal vibrator and at least some of said circuit elements arranged thereon; circuit substrates other than said first circuit substrate that are arranged in a vertical direction with respect to said first circuit substrate and that have said crystal vibrator and circuit elements other than said some circuit elements arranged thereon; and a metallic container that houses said crystal vibrator, said circuit elements, said first circuit substrate having these crystal vibrator and circuit elements arranged thereon, and the circuit substrates other than this, wherein: the circuit substrates other than said first circuit substrate include a second circuit substrate and a third substrate; on said first circuit substrate or said second circuit substrate, there are arranged said heater element and the circuit element of said oscillating stage thermally bonded to said heater element; on said third circuit substrate, there are arranged the circuit element of said buffering stage, and at least the circuit elements of said temperature control circuit excluding said heater element and said temperature sensor element; and said third circuit substrate is arranged so as to be distanced in the vertical direction and thermally isolated by a thermally conductive resin, with a clearance, from said first and second circuit substrates.