# US 2017/0255504 A1 · Fault detection for a display system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0255504 A1 - Document ID: US20170255504A1 - Status: Published application - Kind: A1 - Application number: 15/058,725 - Filed: 2016-03-02 - Published: 2017-09-07 - Earliest claimed: 2016-03-02 - Assignees: L-3 Communications Corporation - Applicants: L-3 Communications Corporation - Inventors: Mark FLETCHER; Ronald CHRISTIAN; William CUMBY - Web page: https://patentgrep.com/patent/US20170255504A1 ## CPC - G09G 3/006: {Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309)} - G09G 3/2096: {Details of the interface to the display terminal specific for a flat panel (suitable for both CRT and flat panel G09G5/006; specific for a CRT G09G1/167)} - G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)} - G09G 2330/08: Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared - G09G 2330/12: Test circuits or failure detection circuits included in a display system, as permanent part thereof - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract A fault detection system is provided for a display system including an AMLCD. A video processor embeds encoded fault detection data within the digital video stream that is sent directly to the AMLCD. The fault detection data is embedded in such a manner that it is not displayed by the AMLCD. The fault detection data in the digital video stream received by the AMLCD is detected by the AMLCD and is then sent back to the video processor. The video processor compares what was sent with what is received to determine whether there is a difference which may be indicative of a fault in the AMLCD or the path of the digital video stream. As an additional check, the AMLCD may send timing error data to the video processor indicating whether the AMLCD is working properly. The video processor generates and outputs a fault flag to initiate a corrective action if a fault is detected in the AMLCD and/or the path of the digital video stream. ## Claims ### Claim 1 A method for detecting a fault in a display system including an active matrix liquid crystal display (AMLCD), comprising: embedding fault detection data into a portion of a digital video stream that will not be displayed by the AMLCD; transmitting the digital video stream, with the embedded fault detection data, to the AMLCD; receiving detected fault detection data, detected by the AMLCD, from the AM LCD; comparing the embedded fault detection data with the received detected fault detection data detected by the AMLCD; and determining whether there is a fault in the AMLCD or in a path of the digital video stream based on results of the comparison. ### Claim 2 (depends on 1) The method of claim 1, wherein determining whether there is a fault includes detecting a difference between the detected fault detection data and the embedded fault detection data. ### Claim 3 (depends on 1) The method of claim 1, further comprising: receiving timing error data indicating whether a timing error occurred in the AMLCD, wherein determining whether there is a fault in the AMLCD is also based on the received timing error data. ### Claim 4 (depends on 1) The method of claim 1, further comprising outputting a signal to initiate corrective action responsive to determining that there is a fault in the AMLCD or in the path of the digital video stream. ### Claim 5 (depends on 1) The method of claim 1, wherein determining whether there is a fault in the display system or the path of the digital video stream includes determining whether there is a difference between the detected fault detection data and the embedded encoded fault detection data which exceeds a threshold. ### Claim 6 (depends on 1) The method of claim 1, wherein: embedding the fault detection data includes embedding a sequence of fault detection data across multiple consecutive digital video frames of the digital video stream; comparing the embedded fault detection data with the received detected fault detection data includes comparing the sequence of fault detection data embedded across the multiple consecutive digital video frames with a sequence of received detected fault detection data detected across the multiple consecutive digital video frames; and determining whether there is a fault in the display system or the path of the digital video stream includes detecting a difference between the sequence of fault detection data embedded across the multiple consecutive digital video frames and the sequence of received detected fault detection data detected across the multiple consecutive digital video frames. ### Claim 7 (depends on 1) The method of claim 1, wherein the fault detection data includes an encoded carryover pixel (COP) that is unique to a frame, among the plurality of digital video frames, of the digital video stream into which it is embedded. ### Claim 8 (depends on 7) The method of claim 7, wherein the COP is embedded into a blanking interval of the frame of the digital video stream. ### Claim 9 A fault detection system for a display system including an active matrix liquid crystal display (AMLCD), comprising an encoder configured to encode and embed fault detection data into a portion of a digital video frame that will not be displayed on the AMLCD, wherein the digital video frame is output, with the embedded encoded fault detection data to the AMLCD as part of a digital video stream including a plurality of digital video frames; and a comparison unit configured to receive captured fault detection data output by the display system, compare the captured fault detection data with the embedded encoded fault detection data to determine whether there is a difference between the captured fault detection data and the embedded encoded fault detection data, wherein the difference is indicative of a fault in the AMLCD or a path of the digital video frame. ### Claim 10 (depends on 9) The fault detection system of claim 9, wherein the comparison unit outputs a signal to initiate correction action responsive to detecting the difference between the captured fault detection data and the embedded encoded fault detection data. ### Claim 11 (depends on 10) The fault detection system of claim 10, wherein the comparison unit outputs the signal to initiate corrective action responsive to the difference between the captured fault detection data and the embedded encoded fault detection data exceeding a threshold. ### Claim 12 (depends on 9) The fault detection system of claim 9, wherein the encoder embeds a sequence of encoded fault detection data across multiple digital video frames, and the comparison unit detects a difference between a sequence of fault detection data captured across the multiple digital video frames and the embedded sequence of encoded fault detection data. ### Claim 13 (depends on 9) The fault detection system of claim 9, wherein the fault detection data includes an encoded carryover pixel (COP) that is unique to the digital video frame into which it is embedded among a plurality of digital video frames. ### Claim 14 (depends on 13) The fault detection system of claim 13, wherein the encoder uses pseudorandom binary sequence encoding to encode the COP. ### Claim 15 (depends on 13) The fault detection system of claim 13, wherein the COP is embedded into a blanking interval of the digital video frame. ### Claim 16 (depends on 9) The fault detection system of claim 9, wherein the comparison unit also analyzes timing error data received from the display system, wherein the timing error data indicates whether a timing error occurred in the display system.