Light-emitting diode display

• US 6,639,574 B2
• Filed: 01/09/2002
• Issued: 10/28/2003
• Est. Priority Date: 01/09/2002
• Status: Expired

• Current Assignee: Landmark Screens, LLC
• Original Assignee: Landmark Screens, LLC
• Inventors: Scheibe, Paul O.
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Osorio, Ricardo
• Application Number:
  US10/045,096
• Publication Number:
  US 20030128174A1
• Time in Patent Office: 657 Days
• Field of Search: 345/82, 345/83, 345/46, 345/589, 345/590, 345/591, 345/593, 345/594, 345/596-599
• US Class Current: 345/83
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

The present invention relates to a light-emitting diode (“LED”) display apparatus used for a display such as a type of standing signboard. The light-emitting diode display is comprised of light-emitting diodes which use a plurality of colors, including blues, reds and greens, arranged in a specific pattern such as a matrix pattern. The display is appropriate for displaying either a moving or a stationary graphical image by powering the LEDs to combine to produce specific colors.

Claims

1. A method for displaying an image on a light-emitting diode display, the display having a first set of light-emitting diodes capable of emitting light having a first set of at least four chromaticities, method comprising:

identifying at least a first light-emitting diode from said first set capable of emitting light having at least one chromaticity for which an operating parameter is to be minimized;

identifying a first region of chromaticity with a first boundary available through operation of said at least one light-emitting diode and a first subset of said first set of light emitting diodes capable of emitting light having a first subset of chromaticities;

identifying a second region of chromaticity with a second boundary available through operation of a second subset of light emitting diodes capable of emitting light having a second subset of chromaticities;

specifying a desired color;

determining whether the desired color resides within the second boundary;

generating the desired color using the second set of light-emitting diodes if the desired color resides within the second boundary, thereby minimizing said operating parameter; and

generating the desired color using said at least one light-emitting diode and the second set of light-emitting diodes if the desired color does not reside within the second boundary.

2. The method of claim 1, wherein the operating parameter to be minimized is power.

3. The method of claim 1, wherein the operating parameter to be minimized is current.

4. The method of claim 1, wherein the operating parameter to be minimized is operating time.

5. The method of claim 1, further comprising the step of verifying that the desired color resides within the first boundary.

6. The method of claim 1, further comprising the step of verifying that the desired color resides within the first boundary or the second boundary.

7. A light-emitting diode display comprising:

a plurality of pixels arranged in a plurality of rows and columns to display a predetermined image, the plurality of pixels composed of a first set of light-emitting diodes capable of emitting light having a first set of at least four chromaticities;

digital input circuitry to input a digital signal for a desired color and a desired luminance;

a digital-to-analog converter capable of converting the digital signal to an analog signal, the digital-to-analog converter having a dynamic range;

control electronics capable of driving the plurality of pixels; and

a threshold operator capable of determining whether the desired color is within a first region of chromaticity with a first boundary available through operation of at least one light-emitting diode capable of emitting light having a first chromaticity and a first subset of said first set of light emitting diodes capable of emitting light having a first subset of chromaticities, wherein the first subset of light emitting diodes is less than or equal in number to the first set,

the threshold operator further capable of determining whether the desired color is within a second region of chromaticity with a second boundary available through operation of second subset of the first set of light emitting diodes having a second subset of chromaticities, the second subset not including the first light-emitting diode and, wherein the second subset of light-emitting diodes is less than or equal to the first set.

8. The light-emitting diode display of claim 7, wherein the desired color is within the first region of chromacity and the control electronics drives the at least one light-emitting diode and the second set of light-emitting diodes to generate the desired color.

9. The light-emitting diode display of claim 7, wherein the desired color is within the second region of chromacity and the control electronics drives the third set of light-emitting diodes to generate the desired color.

10. The light-emitting diode display of claim 7, wherein the control electronics implements a non-linear control function.

11. The light-emitting diode display of claim 9, wherein the control electronics implements a polynomial function.

12. The light-emitting diode display of claim 9, wherein the control electronics implements a piece-wise linear function.

13. The light-emitting diode display of claim 9, wherein the control electronics implements a control function closely matching human perceptible just-noticeable difference in intensity.

14. The light-emitting diode display of claim 7, wherein the parameter is power.

15. The light-emitting diode display of claim 7, wherein the parameter is current.

16. The light-emitting diode display of claim 7, wherein the parameter is operating time.

17. A light-emitting diode display system comprising:

a first set of light-emitting diodes capable of emitting light having a first set of chromacities, the first set of chromacities being equal to or greater than four;

a first memory device for storing digital information;

a first computer processor capable of executing the steps of

identifying at least one light-emitting diode capable of emitting light having a at least one chromacity from within the first set of diodes for which a parameter is to be minimized;

identifying a first region of chromacity with a first boundary available through operation of the at least one light-emitting diode and a second set of light emitting diodes capable of emitting light having a second set of chromacities, wherein the second set of light emitting diodes is less than or equal to the first set;

identifying a second region of chromacity with a second boundary available through operation of a third set of light emitting diodes capable of emitting light having a third set of chromacities, the third set not including the first light-emitting diode and, wherein the third set of light-emitting diodes is less than or equal to the first set;

specifyng a desired color;

determining whether the desired color resides within the second boundary;

if the desired color resides within the second boundary, generating the desired color using the third set of light-emitting diodes; and

if the desired color does not reside within the second boundary, generating the desired color using the at least one light-emitting diode and the second set of light-emitting diodes.

18. The system of claim 17, wherein the parameter to be minimized is power.

19. The system of claim 17, wherein the parameter to be minimized is current.

20. The system of claim 17, wherein the parameter to be minimized is operating time.

21. The system of claim 17, wherein the first computer processor is further capable of executing the step of verifying that the desired color resides within the first boundary.

22. The system of claim 17, wherein the first computer processor is further capable of executing the step of verifying that the desired color resides within the first boundary or the second boundary.

23. The system of claim 17, wherein a second computer processor is capable of sharing the executing the steps of

identifying at least one light-emitting diode capable of emitting light having a at least one chromacity from within the first set of diodes for which a parameter is to be minimized;

identifying a first region of chromacity with a first boundary available through operation of the at least one light-emitting diode and a second set of light emitting diodes capable of emitting light having a second set of chromacities, wherein the second set of light emitting diodes is less than or equal to the first set;

identifying a second region of chromacity with a second boundary available through operation of a third set of light emitting diodes capable of emitting light having a third set of chromacities, the third set not including the first light-emitting diode and, wherein the third set of light-emitting diodes is less than or equal to the first set;

specifying a desired color;

determining whether the desired color resides within the second boundary;

if the desired color resides within the second boundary, generating the desired color using the third set of light-emitting diodes; and

if the desired color does not reside within the second boundary, generating the desired color using the at least one light-emitting diode and the second set of light-emitting diodes.