Data transmission to optical terminals

1. A method of transmitting information from a handheld device to a terminal, said terminal including a digital imaging system and a platen separate from said digital imaging system, said digital imaging system having a depth of focus corresponding to a range of distances in relation to a surface of said platen, the method comprising:

encoding the information as a barcode pattern;

generating the barcode pattern on a display comprised by the handheld device;

periodically modulating a size of the barcode pattern on the display while maintaining internal relative dimensions within the barcode pattern such that the periodically modulating barcode pattern can be displayed at a range of distances above the platen of the terminal; and

displaying the periodically modulating barcode pattern to the platen and the digital imaging system by positioning the display of the handheld device facing said platen, wherein the periodically modulating barcode pattern together with the depth of focus facilitate accurate reading of said barcode pattern and flexibility in the positioning of the display of the handheld device in relation to the platen.

2. The method recited in claim 1 wherein the barcode pattern comprises a two-dimensional barcode pattern.

3. The method recited in claim 1 wherein the barcode pattern comprises a color barcode pattern.

4. The method recited in claim 1 further comprising changing the barcode pattern on the display, such that the encoded information comprised by the barcode pattern changes, during a time interval when the periodically modulating barcode pattern is displayed to the digital imaging system.

5. The method recited in claim 1 further comprising encrypting the information prior to encoding the information as the barcode pattern, wherein encoding the information as the barcode pattern comprises encoding the encrypted information.

6. The method recited in claim 5 wherein encrypting the information comprises encrypting the information with a one-time encryption key.

7. A handheld device comprising:

a display screen; and

a processor coupled with the display screen and operable to transmit information from the handheld device to a terminal, said terminal including a digital imaging system and a platen separate from said digital imaging system, said digital imaging system having a depth of focus corresponding to a range of distances in relation to a surface of said platen, the processor having:

instructions to encode the information as a barcode pattern;

instructions to generate the barcode pattern on the display screen;

instructions to periodically modulate a size of the barcode pattern on the display screen while maintaining internal relative dimensions within the barcode pattern such that the periodically modulating barcode pattern can be displayed at a range of distances above the platen of said terminal; and

instructions to display the periodically modulating barcode pattern to the platen and the digital imaging system to transmit the information from the handheld device to the terminal such that when the display of the handheld device is positioned facing said platen, the periodically modulating barcode pattern together with the depth of focus facilitate accurate reading of said barcode pattern and flexibility in the positioning of the display of the handheld device in relation to the platen.

8. The handheld device recited in claim 7 wherein the barcode pattern comprises a two-dimensional barcode pattern.

9. The handheld device recited in claim 7 wherein the barcode pattern comprises a color barcode pattern.

10. The handheld device recited in claim 7 wherein the processor further has instructions to change the barcode pattern on the display screen during a time interval when the periodically modulating barcode pattern is displayed to the digital imaging system.

11. The handheld device recited in claim 7 wherein the process further has instructions to encrypt the information prior to encoding the information as the barcode pattern, wherein the instructions to encode the information as the barcode pattern comprise instructions to encode the encrypted information.

12. The handheld device recited in claim 11 wherein the instructions to encrypt the information comprise instructions to encrypt the information with a one-time encryption key.