Display driver and method for driving an emissive video display

• US 6,809,711 B2
• Filed: 05/03/2001
• Issued: 10/26/2004
• Est. Priority Date: 05/03/2001
• Status: Expired due to Term

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Funston, David L.
• Primary Examiner(s): Nguyen, Chanh
• Assistant Examiner(s): Bell, Paul A.
• Application Number:
  US09/848,067
• Publication Number:
  US 20020186187A1
• Time in Patent Office: 1,272 Days
• Field of Search: 345/76, 345/82, 345/98, 345/99, 345/100, 345/204, 345/211, 345/212, 345/213, 345/214, 345/581, 345/667, 345/698, 345/699, 345/55, 713/324
• US Class Current: 345/82
• CPC Class Codes: G09G 2310/0259 with use of an analog or digital ramp generator in the column driver or in the pixel circuit
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]

Abstract

According to a feature of the present invention, a method is provided for using a two-dimensional matrix of light emitting elements to display an image electronically encoded in the form of illumination values. An array of elements including less than all of the elements in the matrix to display the image is defined. A sweep rate for writing the illumination values for the elements in the array is determined, and a sweep signal having the illumination values for the elements in the array is generated, where the sweep signal writes illumination values for the elements in the array at the determined sweep rate. According to another embodiment of the present invention, a display driver generates an image encoded in the form of illumination values. The driver includes an image source and a controller receiving the image from the image source, said controller being adapted to (1) define an array of elements including fewer than all of the elements in the matrix for display of the image (2) determine a sweep rate for writing illumination values to the array of elements, and (3) generate images by writing illumination values to the elements in the array at the sweep rate.

Claims

1. A method for using a two-dimensional matrix of light emitting elements to display an image electronically encoded in the form of illumination values, the method comprising the steps of:

a) defining an array of elements including less than all of the elements in the matrix to display the image;

b) determining a pixel rate for writing the illumination values for the elements in the array;

c) assembling the illumination values for the elements of the array into horizontal scan lines and generating a sweep signal including each scan line; and

d) generating a sweep signal incorporating each of the scan lines wherein the sweep signal writes illumination values for the elements in the array at the determined pixel rate and wherein the number of elements in each horizontal row of the array is not the same and further comprising the step of determining a horizontal sweep rate for each scan line, wherein the horizontal sweep rate for each scan line is at least equal to the pixel rate divided by the number of illumination values in each horizontal scan line.

2. The method of claim 1, wherein step a) comprises defining the elements in the array also based upon the shape of the image to be displayed by the array.

3. The method of claim 1, wherein step a) comprises defining the elements in the array of elements also based upon the size of the image to be displayed by the array.

4. The method of claim 1, wherein step a) comprises defining the elements in the array based upon image content.

5. The method of claim 1, wherein step a) further comprises the steps of selecting a display mode and defining the elements in the array from among a set of predefined arrays based on the display mode selection.

6. The method of claim 1, wherein step b) further comprises determining the pixel rate for the array to be at least equal to the predefined refresh rate of the elements multiplied by the number of elements in the array.

7. The method of claim 1, wherein step b) comprises determining the pixel rate by reference to a look-up table that matches the number of elements in the array to a pixel rate.

8. The method of claim 1, wherein the horizontal sweep rate for each row is at least equal to the pixel rate multiplied by the number of elements in that horizontal row of the array.

9. The method of claim 1, wherein the step of determining a pixel rate further comprises determining a sweep rate for each array, and the step of generating a sweep signal comprises generating more than one sweep signal, with each sweep signal writing illumination values for the elements in each array at a rate that is at least equal to the pixel rate for that array.

10. The method of claim 1, wherein the sweep signal is at least the number of elements in all of the arrays multiplied by the refresh rate of the elements, and the step of generating a sweep signal comprises generating a sweep signal that writes illumination values to the elements of all of the arrays.

11. A method for using a two-dimensional matrix of light emitting elements to display an image electronically encoded in the form of illumination values, the method comprising the steps of:

a) defining an array of elements including less than all of the elements in the matrix to display the image;

b) determining a pixel rate for writing the illumination values for the elements in the array; and

c) generating a sweep signal having the illumination values for the elements in the array wherein the sweep signal writes illumination values for the elements in the array at the determined pixel rate;

wherein more than one image is to be displayed at the same time wherein one array of elements is defined to display each one of said images and wherein the elements in the array of elements are defined based upon the number of images to be displayed.

12. A method for using a matrix display of light emissive elements organized into a vertical array of horizontal rows to display an image encoded in the form of illumination values, the method comprising the steps of:

a) defining a set of horizontal rows having fewer than the total number of horizontal rows in the display for displaying the image;

b) determining a pixel rate for writing illumination values for the image to the elements in the defined set of horizontal rows;

c) generating a sweep signal that writes illumination values to the elements in each row in the set of horizontal rows; and

d) writing a sweep signal having illumination values to the elements in the array at the determined pixel rate wherein the step of defining a set of horizontal rows for displaying the image comprises selecting a set of horizontal rows for displaying the image based upon the content of the image.

13. The method of claim 12, wherein the step of defining a set of horizontal rows for displaying the image further comprises defining a number of rows based upon the shape of the image.

14. The method of claim 12, wherein the step of defining a set of horizontal rows for displaying the image further comprises defining a number of rows based upon the size of the image.

15. The method of claim 12, wherein the step of defining a set of horizontal rows further comprises the steps of selecting a display mode based upon the content of the image and defining the elements in the array from among a set of predefined arrays based on a the display mode selection.

16. The method of claim 12, wherein the pixel rate is at least equal to the predefined refresh rate multiplied by the number of elements in the array.

17. The method of claim 16, wherein the horizontal clock rate is at least equal to the number of horizontal lines in the array multiplied by the refresh rate.

18. A display driver for using a two-dimensional matrix of light emitting elements to display more than one image encoded in the form of illumination values, the driver comprising:

a) an image source; and

b) a controller receiving the image from the image source, said controller being adapted to

(1) define an array of elements comprising fewer than all of the elements in the matrix for display of each image,

(2) determine a pixel rate for writing illumination values to the arrays of elements,

(3) generate images by writing illumination values to the elements in each array at the pixel rate determined for that array,

c) separately enabled row drivers receiving the illumination values and operating the elements of the display in response to the illumination values;

wherein the controller defines at least one array of elements for displaying the images wherein said controller positions the arrays to reduce the number of row drivers that must be enabled to display the images in the arrays.

19. A display driver for using a two-dimensional matrix of light emitting elements to display more than one image encoded in the form of illumination values, the driver comprising:

a) an image source;

b) a controller receiving the images from the image source, said controller being adapted to

(1) define an array of elements comprising fewer than all of the elements in the matrix for display of each image,

(2) determine a pixel rate for writing illumination values to each array of elements,

(3) generate images by writing illumination values to the elements in each array at the pixel rate, and

c) separately enabled row drivers and column drivers receiving the illumination values and operating the elements of the display in response to the illumination values;

wherein the controller enables less than all of the drivers while also enabling at least those row and column drivers necessary to operate the elements in each array and wherein said controller positions the arrays to reduce the number of row and column drivers that are enabled to display the images.