Hilliard-lyons Patent Management, Inc.

Cornelius J Starkey, Iv

Lee T Todd, Jr

Hubbard B Spencer, Iii

Thomas J McSorley

James P Galvin, Jr

Disclosed are systems and techniques for image generation applicable in general to any long persistence display device, particularly one in which contrast builds over a number of frames. The display device disclosed in detail by way of example herein is a high resolution cathodochromic CRT (CCRT) in a projection system. The system includes a deflection generator for the display device capable of writing to at least individual image lines in any order and, in some embodiments, to individually-addressed pixels. In raster-scanned embodiments, an image memory is included, capable of storing pixel data on a line-by-line basis. An image controller serves to read particular lines from the image memory and to write corresponding image lines on the display device. In one embodiment, those scan lines which have no picture information (e.g. all white lines in the case of a CCRT) are skipped as lines are read from the image memory and written to the display device, substantially increasing the frame refresh rate in the time-critical operation of writing to a CCRT. The skipping of lines is perferably implemented by storing a 'skip word' with each line of pixel data in the image memory, each skip word indicating a particular successive line to scan, and thus which lines to skip. The use of 'skip words' also permits programmable interlace to be implemented. 'Rolling writing' techniques of the invention facilitate display of partial raster images which become available line-by-line over a period of time, as well as point writing for annotation.

Programmable interlace with skip and contrast enhancement in long

Disclosed are systems and techniques for alignment of CRT-based display systems, particularly those employing a high resolution cathodochromic projection CRT. The disclosed techniques permit all major CRT-related alignment to be performed at a factory or other centralized facility, with automatic precision alignment in the field of the overall display system, including a CRT assembly as one element. A replaceable, standardized CRT subsystem includes a CRT assembly, itself subject to sample variations, and a non-volatile personality memory, such as an EEPROM, having stored parameters specifically applicable to the CRT assembly on an individual basis. The CRT assembly has no field adjustable parts, but does include elements for electron beam control, such as electromagnetic coils for focus and deflection permanently affixed to the CRT. Thus at the factory, a skilled operator having appropriate equipment available performs an electronic alignment procedure with reference to a particular CRT. In the case of a projection display system, the CRT is mounted during alignment within an optical projection system which represents a standardized optical configuration, identical to the optical configuration in which the CRT will be operated in the field. Alignment parameters are digitally recorded as data in the non-volatile 'personality' memory, which then applies specifically to that CRT assembly. When the CRT subsystem including the CRT assembly and the personality memory are later mated with the display electronics subsystem, the display electronic subsystem reads and correctly interprets the data from the personality memory to effect corrections tailored to that particular CRT. When field replacement of a CRT eventually becomes necessary, the replacement CRT is supplied with its own personality memory, which is plugged into the circuit in place of the original one.

CRT display system with automatic alignment employing personality memory

An improved method for erasure of an image target in a CCRT projection system includes the steps of projecting a defocused electron beam onto the target forming a scan line, establishing an energy level below the erase threshold to prevent erasure of any portion of the target within the single line, scanning multiple lines across the full target, and overlapping the scan lines sufficiently to provide integrated heat energy to cause erasure. The energy level is established at about 75% of the erase threshold or about 0.3 joule/cm.sup.2. The power is preferably set at 30 kv and 400 microamps with a single scan line being established at 0.056 inch. Preferably, the scan line is set to overlap 5-12 times to cause erasure, with the optimum being approximately 8 overlaps. In the related CCRT set up of the erasure mode, after overlapping the scan lines, the energy level is gradually increased until the integrated heat energy is sufficient to cause erasure. With these parameters established, the desired erasure of the target is assured when needed.

Growing community of inventors

Lexington, KY, United States of America

Cornelius J Starkey, Iv