Nihon Dempa Kogyo Co., Ltd.

Hiroyuki Mitome

Manabu Ito

Takeo Oita

Takeshi Uchida

Masakazu Nishiwaki

Daisuke Nishiyama

Hiroyuki Murakoshi

A crystal unit and a thermistor with negative resistance-temperature characteristics are housed in a thermostatic oven heated by a heater. A transistor driving the heater is controlled by an output of a differential amplifier, the thermistor is placed between a power supply voltage and an inverting input of the amplifier, and a first resistor used to adjust the temperature of a zero temperature coefficient point of the crystal unit is installed between the inverting input and a ground point. A second resistor is installed between the power supply voltage and a non-inverting input of the amplifier and a third resistor is installed between the non-inverting input and ground point. One of the second and third resistors is a resistor assembly made up of a plurality of resistance elements and one of these resistance elements is provided with positive resistance-temperature characteristics and adapted to detect ambient temperature.

Oven-controlled crystal oscillator

A metal base having plural protrusions at its bottom is engaged with and placed on standing metal pins in plural through holes provided in a base board, and a circuit board is fitted to an upper end of the metal pins. A crystal resonator is arranged on the circuit board via a heater element, and the metal base is covered with a metal cover, thereby obtaining a sealed structure of the crystal resonator. A two-stage counterbored portion including a first-stage and a second-stage counterbored portions is formed in the bottom of the base board, and a solder or conductive resin is filled in a gap between the first-stage counterbored portion formed around the metal pin inserted into the through hole, and the through hole and the metal pin to fix the metal pin in the though hole. Slits penetrating through the base board are formed around the metal pin.

Surface mounted crystal oscillator

The present invention relates to an oven controlled crystal oscillator that can obtain stable oscillation frequency by reducing a temperature change in an oscillation element. The oven controlled crystal oscillator comprises; a heat-conducting plate mounted on one surface of a circuit board, a crystal resonator mounted on a surface of the heat-conducting plate opposite to the surface of the circuit board, an oscillation element constituting an oscillation circuit together with the crystal resonator, and a thermistor that detects temperature of the crystal resonator, a heating resistance which heats the crystal resonator, and a temperature control element including at least a power transistor, to constitute a temperature control circuit together with the thermistor and the heating resistance. In the oven controlled crystal oscillator, two or more open areas communicating with the heat-conducting plate at least in the thickness direction thereof are formed on the periphery of the heat-conducting plate at positions point-symmetric with respect to the crystal resonator, and one or more of each of the power transistor and the heating resistance are arranged in the same number in all of the open areas.

Oven controlled crystal oscillator

A temperature controlled oscillator is provided with a circuit substrate having a crystal resonator, an oscillating circuit, and a temperature control circuit, arranged on one or both principal surfaces, and a container main body that accommodates the circuit substrate and has mount terminals on an outer bottom surface thereof. The temperature control circuit includes at least a first temperature sensor that detects an operating temperature of the crystal resonator, a second temperature sensor that detects a surrounding temperature of the container main body, and a heating resistor that applies heat to the crystal resonator, and lead wires extend from the circuit substrate and are connected electrically to the mount terminals. An insulation groove that passes through the circuit substrate in a thickness direction is formed between: a first lead wire closest to the second temperature sensor, and the second temperature sensor; and the heating resistor.

Temperature controlled crystal oscillator

A constant temperature oscillator includes a crystal oscillator that is provided upright on a circuit board, an oscillation element arranged on the circuit board and configuring an oscillation circuit in conjunction with the crystal oscillator, and a temperature control element including a heating chip resistance and a thermistor, arranged on the circuit board, and configuring a temperature control circuit that keeps an operating temperature of the crystal oscillator constant, and which is provided with a heat transfer plate between the heating chip resistance and the bottom face of the oscillator container, wherein, the heat transfer plate has a notch into which the heating chip resistance is fitted, and a heat sink lies between the heat transfer plate and the heating chip resistance and closely contacts with them.

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Saitama, Japan

Hiroyuki Mitome