Temperature monitor

1. A passive temperature monitor comprising:

an electronic paper display comprising an electronically active ink, the electronic paper display configured to have a first visual display state and a second visual display state, wherein the electronic paper display is configured to utilize the electronically active ink in at least one of the first visual display state or the second visual display state to produce visual information; and

a passive temperature sensor electrically coupled to the electronic paper display, the passive temperature sensor configured such that when the temperature of the passive temperature sensor attains a predetermined value, the passive temperature sensor directly or indirectly produces a response that is communicated to, or sensible by, the electronic paper display, wherein the response is produced without an energy input other than ambient temperature; and

wherein the electronic paper display is configured to change from the first visual display state to the second visual display state upon receiving the communicated response, or sensing the response, from the passive temperature sensor.

2. The temperature monitor of claim 1 , wherein the predetermined value is attained via a decrease in temperature or an increase in temperature.

3. The temperature monitor of claim 1 , wherein the electronic paper display is bistable.

4. The temperature monitor of claim 1 , wherein the passive temperature sensor comprises a device that indirectly produces a potential difference when the predetermined value is attained, wherein the potential difference is the response communicated to, or is sensible by, the electronic paper display.

5. The temperature monitor of claim 4 , wherein the passive temperature sensor comprises a piezoelectric element and the device is arranged to impart a force on the piezoelectric element when the predetermined value is attained.

6. The temperature monitor of claim 5 , wherein the device is a temperature sensitive mechanical device.

7. The temperature monitor of claim 6 , wherein the temperature sensitive mechanical device is a bimetallic switch or a bimetallic strip.

8. The temperature monitor of claim 1 , wherein the passive temperature sensor comprises a device that directly produces a potential difference when the predetermined value is attained, wherein the potential difference is the response communicated to, or is sensible by, the electronic paper display.

9. The temperature monitor of claim 8 , wherein the device is a thermocouple.

10. The temperature monitor of claim 8 , wherein the passive temperature sensor is a thermocouple.

11. The temperature monitor of claim 1 , wherein the electronic paper display is configured to remain in the second display state regardless of any subsequent changes in the temperature of the passive temperature sensor.

12. A passive temperature monitoring system, comprising:

a first temperature monitor that includes a first electronic paper display comprising an electronically active ink, the first electronic paper display configured to have a first visual display state and a second visual display state, wherein the first electronic paper display is configured to utilize the electronically active ink in at least one of the first visual display state or the second visual display state to produce visual information, and a first passive temperature sensor electrically coupled to the first electronic paper display, the first passive temperature sensor configured such that when the temperature of the first passive temperature sensor attains a first predetermined value, the first passive temperature sensor directly or indirectly produces a first response that is communicated to, or is sensible by, the first electronic paper display, wherein the first response is produced without an energy input other than ambient temperature, and wherein the first electronic paper display is configured to change from the first visual display state to the second visual display state upon receiving the communicated first response, or sensing the first response, from the first passive temperature sensor; and

a second temperature monitor that includes a second electronic paper display comprising an electronically active ink, the second electronic paper display configured to have a first visual display state and a second visual display state, wherein the second electronic paper display is configured to utilize the electronically active ink in at least one of the first visual display state or the second visual display state to produce visual information, and a second passive temperature sensor electrically coupled to the second electronic paper display, the second passive temperature sensor configured such that when the temperature of the second passive temperature sensor attains a second predetermined value, the second passive temperature sensor directly or indirectly produces a second response that is communicated to, or is sensible by, the second electronic paper display, wherein the second response is produced without an energy input other than ambient temperature, and wherein the second electronic paper display is configured to change from the first visual display state to the second visual display state upon receiving the communicated second response, or sensing the second response, from the second passive temperature sensor;

wherein the first predetermined value is lower than the second predetermined value.

13. The temperature monitoring system of claim 12 , wherein the second visual display state of the first temperature monitor is different than the second visual display state of the second temperature monitor.

14. The temperature monitoring system of claim 12 , wherein the first predetermined value of the first temperature monitor is in a range from about −1° C. to 1° C.

15. The temperature monitoring system of claim 12 , wherein the second predetermined value of the second temperature monitor is in a range from about 5° C. to 10° C.

16. The temperature monitoring system of claim 12 , wherein the system is configured to be secured to a product or a set of products.

17. The temperature monitoring system of claim 16 , wherein the configuration includes an adhesive.

18. A package comprising:

a structure sized to contain one or more temperature sensitive devices, which structure includes at least one surface; and

a passive temperature monitor that includes:

an electronic paper display comprising an electronically active ink, the electronic paper display configured to have a first visual display state and a second visual display state, wherein the electronic paper display is configured to utilize the electronically active ink in at least one of the first visual display state or the second visual display state to produce visual information; and

a passive temperature sensor electrically coupled to the electronic paper display, the passive temperature sensor configured such that when the temperature of the passive temperature sensor attains a predetermined value, the passive temperature sensor directly or indirectly produces a response that is communicated to, or sensible by, the electronic paper display, wherein the response is produced without an energy input other than ambient temperature; and

wherein the electronic paper display is configured to change from the first visual display state to the second visual display state upon receiving the communicated response, or sensing the response, from the passive temperature sensor;

wherein the temperature monitor is secured to the surface of the structure.

19. A method of determining whether a product has been exposed to a temperature outside of a desired range, the method comprising:

securing to a product or product packaging at least one passive temperature monitor that includes:

an electronic paper display comprising an electronically active ink, the electronic paper display configured to have a first visual display state and a second visual display state, wherein the electronic paper display is configured to utilize the electronically active ink in at least one of the first visual display state or the second visual display state to produce visual information; and

a passive temperature sensor electrically coupled to the electronic paper display, the passive temperature sensor configured such that when the temperature of the passive temperature sensor attains a predetermined value, the passive temperature sensor directly or indirectly produces a response that is communicated to, or is sensible by, the electronic paper display, wherein the response is produced without an energy input other than ambient temperature; and

wherein the electronic paper display is configured to change from the first visual display state to the second visual display state upon receiving the communicated response, or sensing the response, from the passive temperature sensor; and

visually inspecting the display state of the electronic paper display(s).