Thermochromic bar code

• US 6,685,094 B2
• Filed: 12/03/1999
• Issued: 02/03/2004
• Est. Priority Date: 12/06/1997
• Status: Expired due to Term

• Current Assignee: KLT Techonology Inc., Thermacode Technology LLC
• Original Assignee: Thermacode Technology LLC
• Inventors: Cameron, Jon
• Primary Examiner(s): St. Cyr, Daniel
• Application Number:
  US09/453,545
• Publication Number:
  US 20020056756A1
• Time in Patent Office: 1,523 Days
• Field of Search: 235/468, 235/494, 235/375, 235/491, 235/462.01, 235/462.07, 235/469, 235/470, 503/204, 426/61
• US Class Current: 235/468
• CPC Class Codes: G06K 19/06018 one-dimensional coding
• CPC Class Codes: G06K 19/06046 Constructional details

Abstract

A bar code (10) incorporating thermochromic materials in selected modules (20) such that its code changes with temperature. Below a specified temperature, the bar code (10) displays a first code. Above this temperatures, the bar code (10) displays a second code. The bar code (10) is printed with conventional printing equipment onto conventional printing media, and is scanned with conventional bar code scanning equipment.

Claims

1. A method of producing a bar code, comprising the steps of:

printing bar code modules in a bar code space to define a bar code;

wherein the step of printing the bar code modules includes printing at least one bar code module with a thermochromic material; and

then

later optically scanning the bar code to detect whether a change has occurred in the thermochromic material of the at least one bar code module after the step of printing the bar code modules to thereby determine a storage temperature history of the bar code.

2. The method of producing a bar code of claim 1, wherein the step of printing further comprises:

printing the bar code module entirely with a quondam thermochromic material to define a revocable bar code wherein the bar code can be rendered permanently invisible in response to exposure to temperatures of the storage temperature history to warn a bar code reader of an existing or historically undesirable environmental condition.

3. The method of producing a bar code of claim 1, wherein the step of printing further comprises:

printing at least a second bar code module with at least a second thermochromic material to produce the bar code;

wherein the thermochromic material and the second thermochormic material responds to separate, respective temperature ranges; and

wherein the bar code can display a plurality of predetermined codes, including a null code, in order to measure a series of temperature variations to which the bar code has been subjected after the step of printing.

4. The method of claim 1, wherein the step of later optically scanning comprises the step of scanning the bar code with a bar code reader.

5. The method of claim 4, wherein said step of printing comprises including a plurality of codes which are incorporated into the bar code according to response of the thermochromic material to possible temperatures of the storage temperature history to which the bar cade is exposed after the step of printing.

6. The method of claim 1, wherein said step of printing comprises including a plurality of codes which are incorporated into the bar code according to response of the thermochromic material to possible temperatures of the storage temperature history to which the bar cade is exposed after the step of printing.

7. A bar code, comprising:

a first bar code portion produced in a bar code space;

a second bar code portion produced with a first thermochromic material; and

wherein said first thermochromic material will change appearance in response to historical temperature conditions to which said first thermochromic material is exposed after printing of said produced bar code, whereby existing or historical temperature conditions of said bar code can be determined when said bar code is scanned by a bar code reader, and whereby a plurality of codes can be incorporated into a single produced bar code.

8. A bar code as claimed in claim 7, further comprising a further bar code portion produced with a second thermochromic material wherein said first thermochromic material and said second thermochromic material respond to different respective temperature ranges.

9. The bar code of claim 7, wherein said second bar code portions comprises:

a revocable bar code portion produced entirely with a quondam thermochromic material, and

whereby said revocable bar code portion can be rendered permanently invisible to notify of an existing or historically environmental condition in an automated fashion.

10. A bar code comprising:

a bar code portion produced with a first thermochromic material, and

at least one additional bar code portion produced with a second thermochromic material,

wherein each of the first and second thermochromic materials responds to separate, respective temperature ranges; and

wherein said bar code can simultaneously display a plurality of predetermined codes, including a null code in order to indicate during a single bar code read, temperature variations to which said bar code has been exposed after said bar code was produced.

11. A bar code printed in a bar code space, said bar code comprising:

a plurality of digit regions disposed in the bar code space, in a preselected spacial relation;

one of said digit regions having a temperature module which is disposed in a distinct relative relation within said preselected spacial relation of said plurality of digit regions;

said temperature module having a thermochromic material disposed therein, wherein said thermochromic material is defined such that a color characteristic thereof is responsive to exposure to ambient temperatures relative a predetermined temperature value; and

wherein exposure of the bar code space to the ambient temperatures relative to the predetermined value changes a temperature of said thermochromic material of said temperature module relative to the predetermined temperature value, such that said color characteristic is changed in response to the temperature which changes a value for said temperature module and said digit to enable determining exposure of said bar code, after said bar code is produced, to the temperature by means of a bar code scanner.

12. The bar code of claim 11, wherein said thermochromic material is of a type which undergoes a permanent change in said color characteristic in response to changes in the temperature relative to the predetermined temperature value, after the bar code is produced.

13. The bar code of claim 11, wherein said thermochormic material and said bar code together comprise a second bar code printed in the bar code space initially occupied by said bar code, with said second bar code appearing in response to changes in ambient temperature to which said thermochromic material is exposed after said bar code is produced.

14. A method of monitoring environmental conditions of a product during a selected time duration, comprising the steps of:

providing a thermochromic material which in response to exposure to a selected one of the environmental conditions will change state;

including a marking of the thermochromic material in a bar code associated with the product, in a substantially fixed relational proximity to the product for the selected time duration; and

then, after expiration of the selected time duration,

optically scanning the marking to determine the state of the thermochromic material and identify whether the product has been exposed to the selected one of the environmental conditions.

15. The method of claim 14, wherein the step of providing comprises providing a thermochromic material which is of a quondom type, such that exposure to the selected one of the environmental conditions results in a permanent change in the state of the thermochromic material.

16. The method of claim 15, wherein the bar code is printed entirely of the thermochromic material, such that the bar code is rendered permanently illegible when exposed to the selected environmental condition.

17. The method of claim 14, wherein the step of providing comprises providing a thermochromic material which is of a type other than a quondom type, such that exposure to the selected one of the environmental conditions results in a reversible change in the state of the thermochromic material.

18. The method of claim 17, wherein a second marking of a quondom type of thermochromic material is included as a second marking in the bar code which is associated with the product, such that exposure to one of the environmental conditions results in a permanent change in the state of the thermochromic material of the second marking.

19. The method of claim 14, wherein a second marking of a quondom type of thermochromic material is included as a second marking in the bar code which is associated with the product, such that exposure to one of the environmental conditions results in a permanent change in the state of the thermochromic material of the second marking.

20. The method of claim 14, wherein the selected environmental condition is exposure to a selected temperature which is outside of a desired temperature range for the product.

21. The method of claim 20, wherein the desired temperature range for the product corresponds to a positional location for the product in a facility.

22. The method of claim 21, wherein the selected time duration is selected to correspond to a time duration running from when the marking of thermochromic material is associated with the product until removal of the product from the facility.

23. The method of claim 22, wherein a second marking of a quondom type of thermochromic material is included as a second marking in the bar code which is associated with the product, such that exposure to one of the environmental conditions results in a permanent change in the state of the thermochromic material of the second marking.