Code reader

• US 20060138233A1
• Filed: 12/29/2004
• Published: 06/29/2006
• Est. Priority Date: 12/29/2004
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Huomo, Heikki, Korhonen, Raimo, Kemppainen, Antti, Strommer, Esko
• Granted Patent: US 7,490,772 B2
• Time in Patent Office: Days
• US Class Current: 235/451
• CPC Class Codes: G06K 19/067 Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
• CPC Class Codes: G06K 7/081 electrostatic, e.g. by detecting the charge of capacitance between electrodes

Abstract

A method for reading a code, which code comprises code elements and the first part of the code elements is substantially conductive and the conductivity of the second part is substantially different from that of the first part, in which method the reader couples to the code in a capacitive manner, in which case the signal level of the signal formed by the reader varies according to the conductivity of the code element, and a correction factor is determined of at least one code element for correcting the signal. In addition, the invention relates to a code reader and electric ink.

Claims

1. A method for reading a code, which code comprises code elements and the first part of the code elements is substantially conductive and the conductivity of the second part is substantially different from that of the first part, in which method the reader couples to the code in a capacitive manner, in which case the signal level of the signal formed by the reader varies according to the conductivity of the code element, wherein a correction factor is determined of at least one code element for correcting the signal.

2. The method according to claim 1, wherein the signal is adjusted on the basis of the correction factor in order to correct the signal.

3. The method according to claim 2, wherein the adjusting takes place on the time domain of the signal.

4. The method according to claim 2, wherein that the adjusting is linear on the reading range of the code.

5. The method according to claim 2, wherein the adjusting changes on the reading range of the code.

6. The method according to claim 1, wherein the code comprises several code elements for correcting the signal.

7. The method according to claim 6, wherein the correction is based on comparing predefined code elements.

8. The method according to claim 7, wherein the pre-determined code elements are located in the beginning and the end of the code.

9. The method according to claim 1, wherein said correction factor is received from another code separate from the code.

10. The method according to claim 9, wherein the other code is located above and/or below the actual code.

11. The method according to claim 9, wherein the reader is arranged to read the other code simultaneously while reading the actual code.

12. The method according to claim 1, wherein said correction factor is arranged to correct the signal deviation caused by the changes in the reading speed of the code.

13. The method according to claim 1, wherein the second reader is arranged to read said code a second time in such a manner that the correction is performed from the delay between the signals.

14. The method according to claim 6, wherein the mutual size differences of the code elements are identified on the basis of the duration of the signal level.

15. The method according to claim 6, wherein the mutual size differences of the code elements are identified on the basis of the amplitude of the signal level.

16. The method according to claim 6, wherein the speed of the reader in relation to the code is determined on the basis of the mutual size differences of the code elements.

17. The method according to claim 6, wherein the speed correction used for interpreting the code is determined on the basis of the mutual size differences of the code elements.

18. The method according to claim 1, wherein the first part of the code element is made of conductive ink.

19. The method according to claim 18, wherein the ink is arranged to be conductive on the frequency of the electromagnetic field generated by the reader.

20. The method according to claim 1, wherein the code comprises at least two bars, which are the same by their conductivity.

21. The method according to claim 1, wherein the code comprises several bars, whose conductivity values are substantially different from each other.

22. A code reader for reading a code, which code comprises code elements, and the first part of the code elements is substantially conductive and the conductivity of the second part is substantially different from that of the first part, and the code reader is

arranged to couple to the code in a capacitive manner, and

arranged to form a signal, whose signal level varies according to the conductivity of the code element,

wherein the code reader in addition comprises a member, which is arranged to determine a correction factor for correcting the signal.

23. The code reader according to claim 22, wherein the member is arranged to determine said correction factor from at least one code element.

24. The code reader according to claim 23, wherein on the basis of the correction factor the member is arranged to adjust the signal for correcting the signal.

25. The code reader according to claim 24, wherein the member is arranged to adjust the signal on a time domain.

26. The code reader according to claim 24, wherein the adjusting is linear on the reading range of the code.

27. The code reader according to claim 24, wherein the adjusting changes on the reading range of the code.

28. The code reader according to claim 22, wherein the member is arranged to determine the correction factor from several code elements and that the code comprises several code elements for correcting the signal.

29. The code reader according to claim 28, wherein the correction is based on comparing predefined code elements.

30. The code reader according to claim 29, wherein the pre-determined code elements are located in the beginning and the end of the code.

31. The code reader according to claim 23, wherein the member is arranged to receive said correction factor from another code that is separate from the code.

32. The code reader according to claim 31, wherein the other code is located above and/or below the actual code.

33. The code reader according to claim 31, wherein the reader is arranged to read the other code simultaneously with reading the actual code.

34. The code reader according to claim 23, wherein said correction factor is arranged to correct the signal deviation caused by the changes in the reading speed of the code.

35. The code reader according to claim 23, wherein the second reader is arranged to read said code a second time in such a manner that the member is arranged to perform the correction from the delay between the signals.

36. The code reader according to claim 22, wherein the code reader is arranged to determine the mutual size differences of the code elements according to the detected edges of the signal.

37. The code reader according to claim 22, wherein the code reader is arranged to determine the mutual size differences of the code elements according to the amplitude of the signal level.

38. The code reader according to claim 22, wherein the code reader is arranged to determine the speed of the reader in relation to the code on the basis of the mutual size differences of the code elements.

39. The code reader according to claim 22, wherein the code reader is arranged to determine the correction factor used in interpreting the code on the basis of the mutual size differences of the code elements.

40. The code reader according to claim 22, wherein the sensor head comprises two or more electrodes.

41. The code reader according to claim 40, wherein two or more electrodes are placed in the code reader in such a manner that they are consecutive in relation the reading direction of the code.

42. The code reader according to claim 22, wherein the coder reader is connected to at least one of the following:

a mobile terminal, a communication device, an electronic notebook, a personal digital assistant.

43. The code reader according to claim 22, wherein the first part of the code element is made of conductive ink.

44. The code reader according to claim 43, wherein the ink is arranged to be conductive on the frequency of the electromagnetic field generated by the reader.

45. The code reader according to claim 22, wherein the code comprises at least two bars, which are the same by their conductivity.

46. The code reader according to claim 22, wherein the code comprises several bars, whose conductivity values are substantially different from each other.

47. A mobile device, which comprises a code reader for reading a code, which code comprises code elements, and the first part of the code elements is substantially conductive and the conductivity of the second part is substantially different from that of the first part, and the code reader is

arranged to couple to the code in a capacitive manner, and

arranged to form a signal, whose signal level varies according to the conductivity of the code element,

wherein the code reader in addition comprises a member in connection with the sensor head, which is arranged to determine a correction factor for correcting the signal.

48. A conductive ink, which determines a code, which comprises code elements in such a manner that the first part of the code element is substantially conductive and the conductivity of the second part is substantially different from that of the first part, which code determined by the ink is arranged to couple in a capacitive manner to the reader in order to vary the signal level of the signal according to the conductivity of the code element in the reader, wherein a correction factor for correcting the signal can be determined from the code element made of the ink.