Method and apparatus for automatically maintaining a predetermined image quality in a display system

• US 6,075,513 A
• Filed: 03/28/1996
• Issued: 06/13/2000
• Est. Priority Date: 03/17/1994
• Status: Expired due to Term

• Current Assignee: NVIDIA Corporation
• Original Assignee: Cirrus Logic Incorporated
• Inventors: Ramamurthy, Sriram, Reddy, Modugu V., Reddy, Dayakar C.
• Primary Examiner(s): CHANG, KENT WU
• Application Number:
  US08/624,188
• Time in Patent Office: 1,538 Days
• Field of Search: 345/101, 345/102, 345/112, 345/204, 345/214, 345/200, 345/192, 345/193, 345/87, 345/213, 382/300, 395/200
• US Class Current: 345/589
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2370/04 Exchange of auxiliary data, i.e. other than image data, between monitor and graphics controller
• CPC Class Codes: G09G 2370/045 using multiple communication channels, e.g. parallel and serial
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04

Abstract

A digital system provides command data to a display system during the display time period such that minimal image degradation occurs. The digital system includes a CPU coupled to a graphics controller coupled to a display system via a cable. The display system includes an intelligent display driver controller (IDDC), driver circuits, display screen, and possibly sensors. The IDDC operates on image data and instructs the driver circuits to display an image on the display screen. Operating condition changes measured by transducers may result in a degradation in image quality unless a response is made. The digital system may automatically respond to operating condition changes to maintain a predetermined image quality level. Alternatively a user'"'"'s request may change the image quality. In either case the CPU is interrupted and it provides one or more control sets of command data interspersed within the image data transparently to the graphics controller. The IDDC receives one or more control sets from the graphics controller and may store a control set to adjust the control over the driver circuits thereby preserving the image quality. Changes to hardware and software are minimized to reduce the costs of adding these improvements.

Claims

1. A display system comprising:

a host processor, for generating display information and for generating a plurality of control set data for controlling a display device in response to a measured parameter;

a display controller, coupled to the host processor for receiving display information and for generating units of display data, the display controller including;

means for transferring units of display data from the display controller to a display device;

a replacing circuit coupled to the means for transferring, for automatically replacing units of display data with a plurality of sets of control data for transfer with the display data;

a display device, including;

a flat panel display, a display driver controller, for controlling operation of the flat panel display to display pixels on the display device represented by the display data, the display driver controller including;

a digital memory coupled to the display device for storing a selected control data set having a predetermined effect upon the image quality;

means for retrieving selected control data from the display data and modifying the control data set within the digital memory with the control data; and

means for replicating at least one pixel corresponding to the at least one unit based on a value of a neighboring unit of display data within a single frame;

wherein the display driver controller further comprises;

at least one sensor for measuring a value of at least one parameter indicative of an operating condition of the display device, the at least one parameter having a predetermined effect upon quality of the image; and

means for selecting one of the plurality of control sets as a function of the measured at least one parameter, wherein the display driver controller individually and automatically selects particular corrected color levels corresponding to the precorrected color levels from the selected control set.

2. A method of transferring control data to a display device during a display time while maintaining image quality, the method comprising the steps of:

sending a signature from a display controller to the display device during the display time as display data;

sending at least one control data set from a display controller as display data to the display device during the display time;

detecting, at the display device, the signature and control data set from within the display data;

storing, in the display device a control data set for use in controlling image quality of the display;

measuring, in the display device, a parameter of the display;

selecting, in the display device, a portion of the control data set to control image quality of the display in response to the measured parameter; and

replacing the control data set portion of the display data by replicating at least one pixel data based on a value of neighboring pixel data within a single frame during the sending of control set data.

3. A computer system comprising:

a display device for displaying an image comprising a plurality of pixels, said display device including;

a display driver controller and column and row pixel drivers coupled to the display driver controller, the display device for displaying an image comprising a plurality of pixels,

at least one sensor for measuring a value of at least one parameter indicative of an operating condition of the display device, the at least one parameter having a predetermined effect upon quality of the image, and

a digital memory storing a plurality of control sets, each of the plurality of control sets corresponding to a particular value of the at least one parameter, each of the plurality of control sets including a plurality of corrected color levels, each of the plurality of corrected color levels being associated with a corresponding one of the plurality of possible color levels; and

a display controller coupled by a set of signal lines to the display device, the signal lines configured to provide a plurality of precorrected color levels from the display controller to the display driver controller, each of the plurality of precorrected color levels indicating one of a plurality of possible color levels for a corresponding one of the plurality of pixels of the image;

wherein the display driver controller selects one of the plurality of control sets as a function of the measured at least one parameter, wherein the display driver controller individually and automatically selects particular corrected color levels corresponding to the precorrected color levels from the selected control set, and wherein the display driver controller transmits the selected corrected color levels to the column and row pixel drivers for displaying the image, each of the selected corrected color levels corresponding to a respective one of the plurality of pixels of the image.

4. The computer system according to claim 3, further comprising:

an interrupt signal line coupling the display controller to the display device, wherein an interrupt signal is transmitted to the display controller when a value of the at least one parameter changes by a predetermined threshold amount, and wherein the display driver controller selects one of the plurality of control sets only after the interrupt signal is transmitted.

5. The system according to claim 4, wherein the digital memory includes a random access memory coupled to the display device.

6. The system according to claim 3, wherein the display controller includes:

a graphics controller for controlling a process of providing the plurality of precorrected color levels from the display controller to the display driver controller, each of the plurality of precorrected color levels indicating one of the plurality of possible color levels for the corresponding one of the plurality of pixels of the image; and

means for substituting at least one of the plurality of precorrected color levels for a corresponding one of the plurality of pixels of the image with control data,

wherein the display driver controller selects one of the plurality of control sets as a further function of the control data.

7. The system according to claim 6, wherein the display driver controller substitutes the substituted at least one of the plurality of precorrected color levels for the corresponding one of the plurality of pixels with a precorrected color level of a particular one of the plurality of pixels adjacent the corresponding one of the plurality of pixels.

8. The system according to claim 3, wherein the control signal is coupled to the display device by a first and second set of signal cables, wherein the display controller provides image data over the first set of signal cables, wherein the display controller provides control data over the second set of control cables, and wherein the display driver controller selects one of the plurality of control sets as a further function of the control data.

9. The system according to claim 3, wherein the digital memory is coupled to the display driver controller.

10. The system according to claim 3, wherein the digital memory includes a nonvolatile memory.

11. The system according to claim 3, wherein the digital memory includes a volatile memory.

12. The system according to claim 3, wherein the color levels include a first level of red, a second level of green, and a third level of blue.

13. The system according to claim 3, wherein the display controller is physically separated from the display device.

14. The system according to claim 3, wherein the at least one sensor measures an operating temperature.

15. The system according to claim 3, wherein the at least one sensor measures a display voltage linearity.

16. The system according to claim 3, wherein the at least one sensor measures a power supply voltage.

17. The system according to claim 3, wherein the display device is a monitor, and the at least one sensor is mounted to the monitor.

18. The system according to claim 3, wherein the least one sensor is connected to the display controller.

19. A method for maintaining a quality of an image displayed on a display device having a display driver controller and column and row pixel drivers coupled to the display driver controller, the method comprising the steps of:

measuring in the display device, a value of at least one parameter indicative of an operating condition of the display device, the at least one parameter having a predetermined effect upon the quality of the image;

providing a plurality of precorrected color levels from a display controller over a set of signal lines to the display driver controller, each of the plurality of precorrected color levels indicating one of a plurality of possible color levels for a corresponding one of a plurality of pixels of the image;

storing a plurality of control sets within the display driver controller, each of the plurality of control sets corresponding to a particular value of the at least one parameter, each of the plurality of control sets including a plurality of corrected color levels, each of the plurality of corrected color levels being associated with a corresponding one of the plurality of possible color levels;

selecting one of the plurality of control sets as a function of the measured at least one parameter;

individually and automatically selecting particular corrected color levels corresponding to the precorrected color levels from the selected control set;

transmitting the selected corrected color levels to the column and row pixel drivers for displaying the image, each of the selected corrected color levels corresponding to a respective one of the plurality of pixels of the image; and

displaying each of the selected corrected color levels corresponding to the respective one of the plurality of pixels of the image.