Thermal Management within Mobile RFID Readers through the Application of Temperature Governed Variable Non-Emissive Intervals

• US 20090052105A1
• Filed: 08/22/2007
• Published: 02/26/2009
• Est. Priority Date: 08/22/2007
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: SOLEIMANI, Mohammad, Chamberlin, Ian, Strzelczyk, Martin, Owens, Albert, Ngo, Son
• Granted Patent: US 7,782,586 B2
• Time in Patent Office: Days
• US Class Current: 361/103
• CPC Class Codes: G06F 1/206 comprising thermal management
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10207 parameter settings related to power consumption of the interrogator

Abstract

A thermal management system and method to control temperature in an RFID reader is described herein. In particular, by inserting variable periods of inactivity (or latency) at the beginning or at the end of each read cycle, proportional to an instantaneous temperature value of the RFID reader, over-heating and damage of RFID reader electronics is prevented. The RFID reader includes a thermal sensor and determines when the high power RF electronics is enabled. If the RFID reader is in an over-heated condition, it can be turned OFF and during this period any requests received on an interface to the RFID reader to perform a read of tag(s) are not processed.

Claims

1. A system for optimizing the operation of a radio frequency identifier (RFID) reader, comprising:

a thermal sensor configured to detect a temperature of an operating environment of the reader;

a controller configured to selectively turn off one or more components of the reader for a period between read operations, wherein a length of the period is based on the detected temperature.

2. The system of claim 1, wherein a component of the reader turned off includes a power amplifier.

3. The system of claim 1, further including a second thermal sensor configured to detect a temperature of a component of the reader.

4. The system of claim 1, wherein the component of the reader is a power amplifier.

5. The system of claim 4, wherein the controller includes programmable logic to alter a duty cycle of the power amplifier.

6. The system of claim 1, wherein the controller includes an analog to digital converter (ADC) coupled to an analog output of the thermal sensor.

7. The system of claim 6, wherein the ADC converts the analog output of the thermal sensor into a digital value corresponding to at least one of a normal temperature range, a hot temperature range and an over-temperature range.

8. A method for optimizing the operation of a radio frequency identification (RFID) reader, comprising:

sensing a temperature associated with an operating environment of the reader;

determining whether the sensed temperature indicates that the reader is operating in a non-optimal region; and

if the reader is operating in a non-optimal region, selecting a length for a time period during which the reader is inactive, wherein a length of the time period is based on the sensed temperature; and

placing one or more components of the reader into an inactive state for the duration of the time period.

9. The method of claim 8, further comprising:

placing the one or more components of the reader into an active state after the time period has elapsed.

10. The method of claim 8, wherein the step of determining comprises:

comparing the sensed temperature with preset temperature thresholds.

11. The method of claim 8, further comprising:

sensing a temperature of a component of a component of the reader.

12. The method of claim 11, wherein the length of the time period is based on the temperature of the operating environment and the temperature of the component.

13. The method of claim 11, further comprising:

sensing a temperature of a power amplifier of the reader.

14. A system for optimizing the operation of a radio frequency identification (RFID) reader, comprising:

means for sensing a temperature associated with an operating environment of the reader;

means for determining whether the sensed temperature indicates that the reader is operating in a non-optimal region; and

means for selecting a length for a time period during which the reader is inactive if the reader is operating in a non-optimal region, wherein a length of the time period is based on the sensed temperature; and

means for placing one or more components of the reader into an inactive state for the duration of the time period.