Nippon Soken, Inc.

Nippondenso Co., Ltd.

Minoru Yamamoto

Tadashi Hattori

Nobuei Ito

Satoshi Nakamura

Tadashi Ozaki

Yoshinori Ootsuka

Hiroshi Uesugi

Tadasi Hattori

Apparatus and process for synthesizing a diamond film of high purity at a high rate. Mixture gas of hydrocarbon gas and hydrogen gas is introduced into an arc discharge to produce a gas plasma. This gas plasma is blown against a substrate to deposit diamond. A plasma current power supply is connected with a third electrode disposed above the substrate to place the third electrode at a positive potential. An electrical current is supplied into the gas plasma from the third electrode. Flow of the electrical current through the plasma promotes the decomposition of the hydrogen and hydrocarbon. A diamond film of high purity can be deposited at a high rate. The invention is characterized in that the substrate is placed at a lower potential than the third electrode or the direction of the electrical current intersects the flow of the gas plasma although the electrical current is passed through the plasma. Therefore, it is unlikely that the accelerated electrons reach the substrate, elevating its temperature. Hence, diamond of high quality can be synthesized.

Apparatus for forming diamond film

A method and apparatus for forming a diamond film, has a casing in which vacuum is maintained at a predetermined value. A substrate is disposed within the casing so that the diamond film is formed thereon. A gas plasma generator for generating a gas plasma near the substrate from a plasma source gas and a carbon source gas by an arc discharge is provided within the casing. A detector detects a factor which is related to a change in a surface temperature of the diamond film, and an electronic controller controls in response to the detected factor the surface temperature of the diamond film so as to maintain such temperature near a predetermined optimal value for forming the diamond film. As the surface temperature is maintained near the optimal value by a feedback control, high purity diamond film is obtained irrespective of the thickness or the forming time thereof.

Method and apparatus for forming a diamond film

A device for synthesizing a diamond at a high synthesis speed and obtaining an improved purity of diamond is provided, and is characterized by having a vacuum vessel maintained under a predetermined vacuum; a positive electrode and a negative electrode arranged within the vacuum vessel so as to be opposed to each other; an arc discharge power source electrically connected to the positive electrode and the negative electrode and applying a predetermined power to cause an arc discharge in a space between the positive electrode and the negative electrode; a gas supply source which generates a gas plasma by flowing a plasma source gas over the arc discharge, and blowing a resulting gas plasma containing a carbon source gas over a substrate arranged downstream thereof; an electrical field application power source for applying an electrical field between an area at which the gas plasma is generated and the substrate, to give the substrate a higher potential and thereby provide a flow of a predetermined amount of current therebetween.

Process for forming diamond film

A device for forming a diamond film has a casing in which a vacuum is maintained to 50 Torr: a positive electrode and a negative electrode are disposed within the casing so that ends of the positive electrode and the negative electrode are opposed to each other through a space: a substrate is disposed near the space between the electrodes, a gas inlet pipe supplies a mixture gas of hydrogen, argon and methane to the space between the electrodes and an arc power supply is connected to the electrodes for supplying a predetermined arc output power thereacross to form an arc discharge column in the space therebetween. By supplying the mixture gas to the arc discharge column of which the temperature is extremely high, the mixture gas is decomposed at a high rate, and a diamond film of high purity grows on the substrate at a high speed.

Method and device for forming diamond film

A device for the detection of ignition misfire in an internal combustion engine is disclosed. A pressure detector detects changes in the combustion pressure of the engine, and a timing detector calculates a reference angular position of the engine. An ignition/misfire detection unit detects occurrences of ignition/misfire. The detection unit compares the output of the pressure detector with predetermined positive and negative reference voltages, and produces signals when these thresholds are passed. The period of a signal produced from the point of positive value detection to the negative value detection is counted and another period which is double the period from the generation of the positive value to the signal from the timing detector unit is counted. These two signals are then compared against one another, using a predetermined program, to detect if ignition or misfire has occurred in the internal combustion engine. A sample and hold circuit may also delay the value obtained by the pressure detector, if necessary.

Ignition/misfire detector for an internal combustion engine

A device for detection of knocking in a diesel engine has a pressure sensor including a piezoelectric element and detecting a rate of change in combustion pressure, an angle sensor for detecting the rotation of the engine or engine speed, and a knocking detector for receiving outputs from the pressure and angle sensors. The knocking detector serves to detect a rate of change in combustion pressure per unit angle upon necessary correction by the engine speed and to compare the obtained rate with a reference rate of 5 atm/deg, at which knocking occurs. Knocking is detected when the detected rate exceeds the reference rate.

Knocking detection device in diesel engine

A device for detecting an abnormality in a pressure detector in an internal combustion engine. This device includes a piezoelectric pressure detector, a timing detection unit, a selective connection unit, and an abnormality detection unit. The abnormality detection unit includes a capacitor connected to an oscillation circuit, and the piezoelectric pressure detector is connected in parallel with the series connection of the oscillation circuit and the capacitor.

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Okazaki, Japan

Minoru Yamamoto