Electronic display sign

• US 5,796,376 A
• Filed: 04/14/1995
• Issued: 08/18/1998
• Est. Priority Date: 12/18/1991
• Status: Expired due to Fees

• Current Assignee: CIE Research Incorporated
• Original Assignee: CIE Research Incorporated
• Inventors: Banks, Archie A.
• Primary Examiner(s): Powell, Mark R.
• Assistant Examiner(s): Srivastava, Vivek
• Application Number:
  US08/422,701
• Time in Patent Office: 1,222 Days
• Field of Search: 345/82, 345/1, 345/2, 345/4-6, 345/903
• US Class Current: 345/82
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09F 9/33 being semiconductor devices, e.g. diodes
• CPC Class Codes: G09G 2300/026 Video wall, i.e. juxtaposition of a plurality of screens to create a display screen of bigger dimensions
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: Y10S 345/903 Modular display

Abstract

An electronic display sign constructed around a system bus architecture is disclosed. The electronic display sign is preferably a modular construction wherein a number of modules are connected together to form a large display sign which is capable of displaying images at rates which exceed thirty frames a second. Display data is formatted and transmitted to display modules by a sign controller which resides on one of the panels. Each display panel is preferably provided with its own power source.

Claims

1. A modular electronic display sign for displaying bit-tapped image data as discrete points of light wherein the display sign includes X rows and Y columns of light sources, X and Y being integers greater than 1, arranged in at least two modular display panels of X/n rows and Y/n columns per display panel wherein n represents the number of display panels, each light source being individually controllable to display a bit-mapped image of b bits wherein b equals the X times the Y, said electronic display sign, comprising;

a sign controller which includes at least a means for receiving from an external source bit-mapped data signals representative of an image to be displayed on the display sign and control commands that determine a command definable frame display rate for the image independently of the display data and permitting display of images at different frame rates, a memory for storing the bit-mapped data and the control commands, a data transmission means for transmitting the bit-mapped data as addressed bit-mapped data, and a processor for operating the sign controller in accordance with a predefined program of instructions and the control commands that determine the command definable frame display rate for the image,

at least one sign system bus connected to the data transmission means;

at least two display panels having respective display surfaces which support an array of electrically powered light sources and an electronic circuit in connection with the light sources so that any one of the light sources may be selectively powered on; and

a panel control card associated with each display panel, each panel control card generating timing signals for powering on the light sources, and each panel control card being connected with a one of the at least one sign system bus and an electric power source, said panel control card being adapted to receive said addressed bit-mapped data signals from the system bus, which addressed bit-mapped data signals are representative of an image to be displayed by the light sources on the panel and to drive each light source using electric current from the power source in accordance with the signals in order to continuously display the image at a predefined refresh rate in accordance with timing signals generated by the panel control card until a new bit-mapped data signal addressed to the panel is received by the panel or a system reset signal is received by the panel.

2. The electronic display sign as claimed in claim 1 wherein the electronic circuit for selectively powering on the light sources on the display panel consists exclusively of a latch array and a sector drive circuit.

3. The electronic display sign as claimed in claim 2 wherein the light sources on the display surface comprise light emitting diodes.

4. The electronic display sign as claimed in claim 3 wherein the display surface supports 512 light emitting diodes.

5. The electronic display sign as claimed in claim 4 wherein the latch array includes 64 latches and the sector drive circuit includes 8 sector drivers.

6. The electronic display sign as claimed in claim 1 wherein the sign system bus is a standard ribbon cable bus.

7. The electronic display sign as claimed in claim 6 wherein the sign system bus includes eight data conductors, a data strobe conductor and an address strobe conductor.

8. An electronic display sign as claimed in claim 2 wherein the panel control card further includes DIP switches for selecting an address for the display panel.

9. An electronic display sign as claimed in claim 8 wherein the control card includes five DIP switches for selecting a five bit address for the control card.

10. An electronic display sign as claimed in claim 2 wherein the panel control card further includes DIP switches for fine tuning the power pulse width of the drive signal for the light sources so that the pulse width of the drive signals for the light sources may be used to match the steradiance of two or more panels respectively constructed with light emitting diodes from different production batches.

11. An electronic display sign as claimed in claim 1 wherein the data transmission means comprises a sign system bus driver circuit which includes an address coder, a first-in-first-out device and a state machine.

12. The electronic display sign as claimed in claim 11 wherein the first-in-first-out device is 9 bits wide and the processor uses the address coder to set a 9th bit in the first-in-first-out device to 1 if a byte loaded by the processor to the first-in-first-out device is an address byte and to 0 if the byte is a data byte.

13. The electronic display sign as claimed in claim 12 wherein the sign system bus is a standard ribbon cable having a capacity for at least eight data conductors, a data strobe conductor and an address strobe conductor.

14. The electronic display sign as claimed in claim 13 wherein the state machine drives the data strobe conductor high if the 9th bit of the first-in-first-out device is set to zero and drives the address strobe conductor high if said 9th bit is set to one.

15. The electronic display sign as claimed in claim 1 wherein the panel control card comprises a bus buffer connected to a one of the at least one sign system bus, a memory for storing the data signals received from the sign system bus and a controller for driving a latch array and at least one sector driver with current from the power source to power on the light sources in accordance with the data signals.

16. The electronic display sign as claimed in claim 15 wherein the controller operates in one of a data acquisition mode and a display refresh mode, the sign normally operates in the display refresh mode, and the display refresh mode is disabled when the sign is in the data acquisition mode.

17. A modular electronic display sign for displaying bit-mapped image data as discrete points of light wherein the display sign includes X rows and Y columns of light sources, X and Y being integers greater than 1, arranged in at least two modular display panels of X/n rows and Y/n columns per display panel wherein n represents a number of modular units, each light source being individually controllable to display a bit-mapped image of b bits wherein b equals the X times the Y, said modular display sign comprising:

a sign controller which includes at least one means for receiving from an external source bit-mapped data signals representative of images to be displayed on the display sign and control commands that determine a command definable frame display rate for the image independently of the display data and permitting display of images at different frame rates, a memory for storing the bit-mapped data signals and the control commands, at least one sign system bus driver, and a processor for operating the sign controller in accordance with a pre-defined program of instructions and the control commands command definable frame display rate for the image;

a sign system bus connected to each of the at least one sign system bus driver;

at least one display panel connected to each sign system bus, the at least one display panel having a display surface which supports an array of electrically powered light sources and an electronic circuit in connection with the light sources so that any one of the light sources can be selectively powered on;

a panel control card associated with each display panel, the panel control card including a sign system bus buffer connected to the sign system bus, a memory, and a controller for generating timing signals, the panel control card further including means for assigning an address to the panel control card, and the controller operating to store in the memory data transferred by the sign controller on the sign system bus and addressed to the panel control card, and the controller further operating the electronic circuit and a power source to selectively power on the light sources in accordance with the data in a continuous refresh cycle in accordance with the timing signals generated by the controller whenever new data is not being received and the panel control card has not received a system reset signal.

18. The modular electronic display sign as claimed in claim 17 wherein the power source is a power supply associated with each display panel.

19. The modular electronic display sign as claimed in claim 18 wherein the array of light sources comprise light emitting diodes arranged in a matrix pattern and the electronic circuit comprises an XY grid.

20. A display panel for an electronic display sign of the type wherein a plurality of the display panels are juxtaposed to provide an integrated display surface which supports a plurality of discrete light sources which may be selectively powered on for displaying an image as points of light, said display panel comprising:

a display surface for supporting an array of light sources and an electronic circuit connected to the light sources so that the light sources can be selectively powered on;

a frame connected to the display surface;

a display panel control card connected to the frame, the display panel control card including a sign system bus buffer for connection with a sign system bus, a memory, a drive signal circuit for generating a drive signal to selectively power on the light sources, and a controller to operate the sign system bus buffer, the memory and the drive signal circuit in accordance with a pre-defined program of instructions;

whereby the predefined program of instructions is adapted to operate the display panel to receive from the system bus a block of addressed, bit-mapped display data arranged as consecutive contiguous bytes, which block of addressed bit-mapped display data represents an on/off condition for each of the light sources on the panel, and to drive each light source using electric current from the power source in accordance with the display data in order to continuously display at a predefined refresh rate an image represented by the display data in accordance with timing signals generated by the panel control card until a new block of bit-mapped display data addressed to the panel is received by the panel control card or a system reset signal is received by the panel control card.

21. An electronic display sign comprising:

at least one display panel having a display surface which supports a plurality of discrete electrically powered light sources and an electronic circuit in connection with the light sources so that each of the light sources may be selectively powered on, the display panel including a power source and a display panel controller for generating timing signals for powering on the light sources;

a sign controller for generating data signals representative of a pattern for selectively powering on the light sources and control signals for determining an intensity of illumination of the light sources, the sign controller including at least one interface for receiving display data for generating the data signals and control commands that determine a command definable frame display rate for the pattern independently of the display data and permitting display of images at different frame rates; and

a sign system bus in electrical connection with the sign controller and the display panel controller of the at least one display panel, the sign system bus communicating the data signals and the control signals from the sign controller to the at least one display panel controller to effect illumination of the light sources in accordance with the pattern and specified intensity of illumination, a refresh rate of the illumination of the light sources being controlled in accordance with the timing signals generated by the display panel controller.

22. An electronic display sign as claimed in claim 21 wherein the display panel comprises a modular unit adapted to be juxtaposed with other display panels to form a display sign having a continuous planar display surface.

23. The electronic display sign as claimed in claim 22 wherein the display panel comprises a rectangular display surface, a supporting frame affixed to the display surface, and a power supply and a display panel control card affixed to the supporting frame.

24. The electronic display sign as claimed in claim 23 wherein the display panel control card includes a panel controller, a sign system bus buffer, a memory, and an electronic circuit for selectively driving the light sources on the display panel.

25. The electronic display sign as claimed in claim 24 wherein the electronic circuit for selectively powering on the light sources on the display panel consists exclusively of a latch array and a sector drive circuit.

26. The electronic display sign as claimed in claim 24 wherein the light sources on the display surface comprise light emitting diodes.

27. The electronic display sign as claimed in claim 26 wherein the display surface supports 512 light emitting diodes.

28. The electronic display sign as claimed in claim 27 wherein the latch array includes 64 latches and the sector drive circuit includes 8 sector drivers.

29. The electronic display sign as claimed in claim 21 wherein the sign system bus is a standard ribbon cable bus.

30. The electronic display sign as claimed in claim 29 wherein the sign system bus includes 8 data conductors, a data strobe conductor and an address strobe conductor.