Method of event detection for intraoral image sensor

• US 20040065836A1
• Filed: 12/10/2002
• Published: 04/08/2004
• Est. Priority Date: 10/03/2002
• Status: Active Grant

• Current Assignee: Sirona Dental Systems LLC (Sirona Dental Systems Incorporated)
• Original Assignee: Schick Technologies, Inc.
• Inventors: Schick, David B., Armencha, Valeriy, Mandelkern, Stan
• Granted Patent: US 6,972,411 B2
• Time in Patent Office: Days
• US Class Current: 250/370.01
• CPC Class Codes: A61B 6/512 Intraoral means
• CPC Class Codes: A61B 6/563 involving image data transmission via a network
• CPC Class Codes: H04N 25/709 Circuitry for control of the power supply
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

A method of determining that radiation is incident upon a radiation sensor comprising a plurality of radiation sensitive pixels includes the steps of monitoring an amount of current drawn by the pixels, and generating a signal indicating a presence of incident radiation which the amount of current exceeds a predetermined amount.

Claims

1. A method of determining that radiation is incident upon a radiation sensitive sensor comprising a plurality of radiation sensitive pixels, said method comprising the steps of

monitoring an amount of current drawn by the plurality of radiation sensitive pixels;

generating a signal indicating a presence of incident radiation when the amount of current drawn by the plurality of radiation sensitive pixels exceeds a predetermined amount.

2. The method according to claim 1, wherein the amount of current drawn by the plurality of radiation sensitive pixels is measured using a resistor.

3. The method according to claim 2, wherein the signal indicating the presence of incident radiation is generated by a comparator.

4. The method according to claim 3, wherein the comparator compares a voltage proportional to the amount of current drawn by the plurality of radiation sensitive pixels with a fixed reference voltage.

5. The method according to claim 4, wherein the comparator generates a signal indicating the presence of incident radiation when the voltage proportional to the amount of current drawn by the plurality at radiation sensitive pixels exceeds the fixed reference voltage.

6. The method according to claim 1, wherein said sensor is an intraoral sensor adapted to capture x-ray images inside of a patient'"'"'s mouth.

7. The method according to claim 1, wherein said plurality of radiation sensitive pixels comprises a CMOS active pixel sensor array.

8. A radiation sensitive sensor, comprising

a plurality of radiation sensitive pixels;

an event detection circuit that determines that radiation is incident upon said plurality of pixels based upon an amount of electrical current drawn by said plurality of pixels.

9. A sensor according to claim 8, wherein said event detection circuit includes:

a resistor that senses an amount of current drawn by said plurality of pixels;

a voltage divider that generates a reference voltage; and

a comparator that generates a triggering signal when the voltage across said resistor exceeds the reference voltage.

10. A sensor according to claim 8, wherein said sensor is an intraoral sensor adapted to capture x-ray images inside of a patient'"'"'s mouth.

11. A sensor according to claim 8, wherein said plurality of radiation sensitive pixels comprises a CMOS active pixel sensor array.

12. A radiation sensitive sensor comprising:

means for generating an amount of electrical charge corresponding to an intensity of radiation incident on said sensor;

means for determining that radiation is incident on said generating means based upon an amount of electrical current drawn by said generating means.

13. A radiation sensor according to claim 12, wherein said determining means includes:

means for generating a reference voltage; and

means for generating a voltage proportional to the amount of electrical current drawn by said charge generating means.

14. A radiation sensor according to claim 12, wherein said determining means includes:

means for determining that radiation is incident on said charge generating means when the voltage proportional to the amount of current drawn by said charge generating means exceeds the reference voltage.

15. A radiation sensor according to claim 12, wherein said sensor is an intraoral sensor adapted to capture x-ray images inside of a patient'"'"'s mouth.

16. A radiation sensor according to claim 12, wherein said charge generating means comprises a CMOS active pixel sensor array.