Showing papers on "Junction temperature published in 1983"

Semiconductor laser module having an improved temperature control arrangement

Abstract: A semiconductor laser device is provided including semiconductor laser element, a PN-junction element which is used for temperature detection, and a thermoelectric heat pump which is electrically connected to the PN-junction element. According to this arrangement, heat developing from the semiconductor laser element is sensed by exploiting the fact that the forward voltage V F of the PN-junction element or PN-junction diode changes in correspondence with the change of the ambient temperature (this phenomenon itself is a matter already known), and the change of the forward voltage V F is fed back to the thermoelectric heat pump. Therefore, even when the semiconductor laser device is placed in the condition of a very high ambient temperature (open air temperature), the semiconductor laser element is cooled down to a predetermined temperature by the thermoelectric heat pump so as to produce a prescribed optical power at all times. Thus, the semiconductor laser element itself is driven in an appropriate temperature condition (for example, 25° C.), so that the degradation of the semiconductor laser element can be prevented.

Thermal Runaway Prevention in Arc Spots

Abstract: After recapitulation of the energy balance equation of cathode arc spots, the condition of thermal runaway is derived, i.e., of the unlimited increase of the temperature at a finite critical current density, because of temperature dependent resistive heat generation. It is shown that in arc spots such a thermal runaway is not possible for two reasons. First, the temperature dependent electron emission cooling forces a limitation of the stationarily achievable temperature (negative feedback). The current density remains limited, however. Second, the short time scale of arc spot development (crater formation time, ~10 ns) is not sufficient for thermal runaway that needs ~100 ns (order-of-magnitude values), besides the case of very small protrusions, where the time scale drops to less than 0.1 ns.

New progress in the development of a 94-GHz pretuned module silicon IMPATT diode

Abstract: This paper presents 94-GHz pretuned modules with high efficiency. A description of device process and packaging technology is presented. CW output power levels of 345 mW with gold integrated heat sink and 800 mW with diamond heat sink have been achieved from double-drift IMPATT diodes at frequencies around 94 GHz, simultaneously with an efficiency around 10 percent and a junction temperature of 200-250°C.

Picture forming device

Abstract: PURPOSE:To record to a recording medium such as a photosensitive drum with the beam of a stabilized output, by detecting that the semiconductor laser reaches its steady state by a detection means outputting a permission signal for drive of a semiconductor laser detecting directly and easily the temperature at a junction part of a semiconductor laser (LD) element to always keep the temperature of the junction part at a fixed level. CONSTITUTION:When the temperature at a junction part of an LD element L exceeds a standard working temperature, the forward voltage is increased. Then the holding voltage Ef beomes higher than the set voltag Eg, and voltages Eh and Ei go to positive and negative respectively. As a result, transistors TR4 and TR5 are turned on and a current flows through a Peltier element PD toward an arrow head (j) to cool the element L. When the junction temperature of the element L is low, the Ef is lower than the Eg. Then the Eh and Ei go to negative and positive respectively. Thus TR3 and TR6 are turned on and a current flows through the element PD toward an arrow mark (k) to heat the element L. It is also possible to detect the junction temperature of the element L even under laser oscillation of the element L.

Thermally stabilized IMPATT oscillator

Abstract: An IMPATT oscillator is thermally stabilized for pulsed operation by utilizing the dissipative heat during subperiods of pulsed operation and a variable self-heating due to a bias voltage applied during non-oscillating subperiods. The oscillator comprises an IMPATT diode mounted on a platform which is attached to a housing defining a resonating cavity. The platform has a thermally insulating base with a layer of thermally and electrically conducting material applied thereon. The thickness of the layer of thermally and electrically conducting material must be sufficient to permit microwave resonances to occur within the cavity. The thermal resistance of the layer is selected to permit the junction temperature to remain constant even for the highest ambient temperature condition. Constant junction temperature over a wide range of ambient temperature produces constant power and frequency characteristics.

New Progress in a Development of a 94 GHz Pretuned Module Silicon Ikpati Diode

Abstract: Use of low pressure epitaxy and mainly a batch process for integrated heat sink technology, associated with a very low inductive quartz encapsulation giving a radial impedance match, are described. Results for two types of these pretuned modules, one on copper the other on Diamond IIa, are given for CW oscillations reaching 800 mW with 10 % efficiency and junction temperature rise of 200°C.

Device for measuring temperature of high-temperature furnace

Abstract: PURPOSE:To measure the temperature in a furnace even at the time of an accident, by switching a constant voltage compensating power supply to a variable compensation power supply even when the temperature in a thermostatic chamber exceeds a prescribed temperature CONSTITUTION:When a trouble such as an accident in a reactor is generated, the atmosphere of the inside of a magazine 2 is changed and the temperature in the thermostatic chamber 3 can not be kept at a prescribed cold junction temperature, the inputted resistance value of a temperature measuring resistor 15 exceeds a stored resistance value, so that a comparator 17 outputs a command signal indicating the switching of a relay 13 to connect the variable compensation power supply 16 to an adder 12 Since the variable compensation power supply 16 converts the inputted resistance value of the temperature measuring resistor 15 into the thermoelectromotive force of a reference contact (y) at the temperature in the thermostatic chamber at that time and outputs the converted thermoelectromotive force, the adder 12 outputs voltage equal to the thermoelectromotive force of a measuring contact X, making it possible to measure the temperature in the furnace