Electric device and method of driving the same

• US 6,550,325 B1
• Filed: 10/27/1993
• Issued: 04/22/2003
• Est. Priority Date: 10/27/1992
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Teramoto, Satoshi, Rimantas, Vaitkus, Hiroki, Masaaki, Sato, Eiji, Inushima, Takashi
• Primary Examiner(s): PATEL, HARSHAD R
• Application Number:
  US08/141,632
• Time in Patent Office: 3,464 Days
• Field of Search: 338/225, 732/041.9, 732/042.5, 732/042.3, 732/042.6, 732/042.7
• US Class Current: 73/204.26
• CPC Class Codes: G01F 1/688 using a particular type of heating, cooling or sensing element G01F1/6847 takes precedence
• CPC Class Codes: G01F 15/006 characterised by the use of a particular material, e.g. anti-corrosive material G01F15/14 takes precedence

Abstract

A thermistor layer made of platinum is formed on a thin diamond film. An amount of heat carried away from the diamond film by a fluid is detected as a change in the temperature of the thermistor layer. The rear side of the diamond film is kept in contact with the fluid to prevent the material of the thermistor from being corroded by the fluid. In another aspect of the invention, a heating element and a thermistor are formed on one surface of a thin diamond film. The other surface is kept in contact with a fluid. The diamond film is heated by the heating element in a quite short time of about 0.2 second. The resulting response characteristics of the diamond film are detected by the thermistor. The flow rate is calculated from the response characteristics.

Claims

1. An electric device for monitoring a fluid comprising:

a diamond film having a first surface and a second surface on an opposite side of said first surface; and

a resistor provided on said first surface of said diamond film and measuring a temperature of said diamond film;

wherein at least said second surface is in contact with the fluid in response to a temperature change of said diamond film resulting from said heat transfer to sense a parameter of the fluid and said resistor is thermally connected with said diamond film.

2. An electric device for monitoring a fluid comprising:

a diamond film having a first surface and a second surface on an opposite side of said first surface; and

a resistor provided on said first surface of said diamond film,

wherein said resistor is thermally connected only with said diamond film, and said second surface is in contact with the fluid.

3. An electric device for monitoring a fluid comprising:

a substrate;

a diamond film supported by said substrate, wherein said diamond film is thermally insulated from said substrate; and

a resistor provided on said diamond film,

wherein said diamond film has an exposed surface to the fluid to be monitored.

4. An electric device for monitoring a fluid comprising:

a diamond film, having one and only one contact surface thereof in contact with the fluid; and

a resistor provided on an opposite surface of said diamond film to said one surface and thermally connected only with said diamond film,

wherein said contact surface is a terminal surface of crystal growth of said diamond film.

5. An electric device for monitoring a fluid comprising:

fluid contact means for providing a monitoring interface with the fluid to be monitored, said fluid contact means comprising a diamond film in direct contact with the fluid;

a heat generator provided on said diamond film; and

a thermally sensitive resistor provided on said diamond film,

wherein said thermally sensitive resistor is thermally connected with said heat generator only through said diamond film.

6. An electric device comprising:

a diamond film;

a heat generator provided on said diamond film; and

a thermally sensitive resistor provided on said diamond film,

wherein said heat generator generates a heat pulse, and said thermally sensitive resistor measures a temperature variation of said diamond film caused by said heat pulse.

7. An electric device provided on a path for passing a fluid therethrough comprising:

a diamond film, one surface of said diamond film forming a part of an inner wall of said path; and

a resistor provided on an opposite surface of said diamond film to said one surface and thermally connected only with said diamond film.

8. An electric fluid monitoring device provided on a path for passing a fluid therethrough, comprising:

fluid contact means for providing a monitoring interface with the fluid path to be monitored, said fluid contact means comprising a diamond film having a first surface and a second surface opposite to said first surface, said second surface in contact with said fluid; and

a resistor provided on said first surface of said diamond film and thermally connected only with said diamond film, said resistor changing resistance in response to a temperature change of said diamond film resulting from heat transfer with the fluid,

wherein said path is divided into a plurality of paths by a separator provided therein.

9. An electric fluid monitoring device comprising:

a fluid path;

a fluid with a Reynolds number of at least 4000 flowing in said fluid path;

fluid contact means on said fluid path for providing a monitoring interface with the fluid path, said fluid contact means comprising a diamond film having a first surface and a second surface opposite to said first surface, at least said second surface in contact with said fluid; and

a resistor provided on said second surface of said diamond film; and

a resistor provided on said first surface of said diamond film and thermally connected only with said diamond film.

10. An electric device comprising:

a diamond film, one planar surface of said diamond film in contact with a fluid; and

a resistor provided on an opposite surface of said diamond film to said one planar surface and thermally connected only with said diamond film,

wherein said one planar surface is oriented in a slanting direction to a direction in which said fluid flows.

11. An electric device comprising:

a diamond film in contact with a fluid;

means for intermittently supplying heat to said diamond film; and

means for measuring a temperature variation of said diamond film caused by said heat.

12. The device of claim 11 wherein flow rate or flow velocity of said fluid is obtained from said temperature variation.

13. The device of claim 11 further comprising means for obtaining output from said temperature variation in proportion to quantity of heat removed from said diamond film by said fluid.

14. An electric device comprising:

a diamond film having an exposed surface to contact a fluid to be monitored with said device;

supporting means for supporting said diamond film, said diamond film thermally insulated from said supporting means;

means for supplying a heat pulse to said diamond film;

means for measuring a temperature of said diamond film; and

means for calculating output from variation of said temperature caused by said heat pulse,

wherein said output is in proportion to quantity of heat removed from said diamond film by said fluid.