Television – Monitoring – testing – or measuring – Testing of image reproducer
Reexamination Certificate
1995-11-06
2001-12-04
Faile, Andrew (Department: 2611)
Television
Monitoring, testing, or measuring
Testing of image reproducer
C348S180000, C348S181000
Reexamination Certificate
active
06326996
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to monitors and televisions, and in particular to a display device having image generation capability without the need for connection to an external signal.
BACKGROUND OF THE INVENTION
Video and graphics display devices, such as television sets and monitors are known to sometimes provide faulty images. Some forms of faulty images include interference or shadowing, where a faint echo of the image is spaced a small distance from the intended image, or is distorted. Further faults include background noise, video ringing, incorrect control functionality, incorrect brightness, pincushion effects and refresh rate problems. Distortion is sometimes referred to as incorrect orthogonality, and is a measure of the geometrical accuracy of the image. Many displays use three color guns, red, green and blue, to generate multicolor images. The color guns must be properly aligned to provide sharp and accurate images. The images displayed on monitors and television sets are usually generated by a computer system in the case of monitors, or from an external broadcast source in the case of televisions. Monitors are also capable of displaying television signals that have been processed by a computer system. The sources of the broadcast signals range from ground based antennas and cable systems to satellite broadcast signals.
Many of the signals provided to television sets require significant processing and tuning prior to viewing on the television. Set top boxes for receiving, tuning and decrypting signals, as well as providing back channel communications to accounting and control facilities of the originator of the signals are common functions of such boxes. As can be seen, there is significant overhead in the equipment associated with the provision of the signal to either a monitor, television, or other type of display device. The complex processing of signals prior to the display device receiving the signal creates a problem with determining the source of a faulty image. Video drivers can be unique to each monitor, and they may also conflict with other software. Interference could be caused by a rain storm in the case of some small dish satellite systems, a nearby electronic device, overhead power lines, metal shelves, or operation of a motor attached to the same power supply system as used by the monitor or computer. It can be difficult to determine whether a faulty image is due to problems with the monitor itself, such as misaligned color guns, or is caused by interference, or problems with the received signal. It may also be caused by having the wrong video driver, or perhaps the video card in the computer is causing the faulty image.
Remote diagnosis by a repair person is virtually impossible, so in many cases, an expensive replacement display is needlessly sent to the user, wasting time, equipment and incurring high postage costs if the problem does not lie in the display. This creates a huge unnecessary burden on technical support services. If the repair person travelled to the display device, they would bring diagnostic equipment which would attach to the display and provide a test pattern as input to the display. The cost of sending a repair person is even more expensive than just shipping a new display. The test pattern comprised various geometric shapes and colors which allowed the repair person to visually inspect the displayed image for at least orthogonality, interference and correct alignment of the color guns. Such equipment is described in U.S. Pat. No. 5,345,263 to Miller. U.S. Pat. No. 5,247,358 to Richards shows the display of video signals stored on a computer for adjusting the brightness of the display. This again requires external equipment to determine the location of a faulty image.
Some display devices have microprocessors and on screen controls that provide menus for adjusting volume, channel and other characteristics of the display, including contrast and brightness. Viewing these menus can provide some clues as to where a faulty image may be originating, however, such menus are not designed for such diagnostic purposes, and do not provide good indications of problems. For instance, the images displayed in such menus usually use only one of the three color guns, and hence are incapable of showing improper alignment. The menu text is usually concentrated away from the edges of the displays, where orthogonality problems are most likely to be detected. A further display device is described in U.S. Pat. No. 4,901,147 to Tajima. The results of internal diagnostic routines are displayed by characters and graphics generated by the display circuitry and superposed on top of a video signal much like the display of on screen controls discussed above. Other monitors, such as a 100 inch monitor manufactured by Sony for military use are also thought to have some form of internal diagnostics.
There is a need for an independent diagnostic tool for displays which does not require additional equipment. There is also a need for a display diagnostic tool which is independent of the external display signals provided by computer systems, set top boxes and directly received from providers of such signals by the display device. There is a further need for a diagnostic tool which provides for ease of moving the display to a different location to determine if a local source of interference is causing the faulty picture. The tool must be simple to use in order for a non-technically oriented user to be able to diagnose problems with or without the aid of a telephone support person. It must also be inexpensive to implement.
SUMMARY OF THE INVENTION
A display device is provided with the capability to provide a self generated diagnostic image which is useful to help determine the functionality of the display device, and to assist in the isolation of problems causing faulty images on the display. In one embodiment, existing circuitry and software which provides on screen display functions is enhanced to provide for display of a predetermined pattern of geometric shapes and colors. The provision of the diagnostic image is activated by a user, either by pressing a button on the display, or via external control signals provided from an attached computer or set top box. The image may be superimposed over existing video images provided by external circuitry, or such external circuitry may be completely disconnected from the display device. In this manner, a user may view the diagnostic image, and determine if distorted images are caused by the display device, or with the external circuitry. In addition, since the image is self generated, the display device may be moved to a different location to help in determining if distortion or interference is being caused by sources external to the display.
In one embodiment, existing on-screen display circuitry is used to store the diagnostic pattern and to display it. This minimizes the cost of implementing the invention. A suitably programmed microprocessor provides for control of the components in the on-screen display circuitry. A read only memory under control of the microprocessor contains the test pattern, and is coupled to a signal generator for generating the red, green and blue signals representative of the pattern which are then provided to a multiplexor. The multiplexor also receives and switches between video input from an external source, and under control of the microprocessor, routes the appropriate signals to the guns and deflection yoke of a cathode ray tube (CRT). The diagnostic pattern may be either superimposed on the video signal, or the video signal may be isolated from the pattern with only the pattern being sent on to the CRT. The isolation also allows video signal connectors to be completely disconnected, and the pattern will still be displayed if desired. User controls are coupled to the microprocessor to enable the display of the diagnostic pattern. They are activated either through a separate switch or combination of buttons or switches, or by holding in a power-on button for a pred
Cool Kenneth J.
Faile Andrew
Gamon Owen J.
Gateway Inc.
Schwegman - Lundberg Woessner - Kluth
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