Abstract: An image having more pixels than can be displayed on a video monitor (16) is stored in an image buffer (10) in packed raster format. During a vertical retrace period, the video monitor generates several horizontal synchronization signals which clock a video memory controller (20). Each time the video memory controller is clocked, it moves a portion of a next successive row of data from the image buffer to a video memory (12). In this manner, several rows of new data are loaded into the video memory before the video monitor starts withdrawing data from the video memory to display the first raster scan line. As the raster scan line is indexed to move down the video image by the horizontal synchronization pulses, the same horizontal synchronization pulses continue to index the row addresses of the video memory controller keeping the transfer of new data into the video memory several lines ahead of the current raster scan line.
Type:
Grant
Filed:
October 9, 1990
Date of Patent:
May 4, 1993
Assignee:
Bell & Howell Publication Systems, Company
Inventors:
Daniel V. Cusick, John E. Conroy, Raymond G. Molnar, O. Nolan Daines
Abstract: An image is stored in raster format having N raster or data lines each with M pixel values in an image or print buffer memory (10). An addressing circuit (20) addresses the print buffer memory to read out m.times.n bit columns or blocks of data, where n=N unless cropping of the image is desired. The blocks are parallel loaded alternately into a first FIFO memory array (40) and a second FIFO memory array (62). Each FIFO memory array includes a plurality of FIFO memories (42a-p 64a-p) which store n data lines segments each of m/p bits. In the first n clock cycles of the first FIFO memory (42a), a multiplexer (46) passes the least significant bit (50) of each data line segment read out of the first FIFO memory. The next N times that the first FIFO memory is clocked, the multiplexer passes the next least significant bit and so on until all m/p bits have been passed serially to a laser printer (48).
Type:
Grant
Filed:
October 3, 1990
Date of Patent:
March 30, 1993
Assignee:
Bell & Howell Publication Systems Company
Inventors:
Daniel V. Cusick, Michael A. Chmura, Raymond G. Molnar
Abstract: Support apparatus for easily and independently adjusting tilt and swivel of a supported product, specifically a visual display device such as a computer monitor. The swivel mechanism permits the display device to be swivelled through a rotational angle greater than 360.degree., or greater than 180.degree. in each direction from a front reference position. The tilt mechanism utilizes a stack of elongate torsion springs or bars with the stack's mid-portion fixed against longitudinal rotation and with its ends rotatable, including means for providing resistance to such rotation, for counter-balancing the torque produced by the display device in its various tilt positions.
Type:
Grant
Filed:
March 6, 1989
Date of Patent:
April 24, 1990
Assignee:
Bell & Howell Publication Systems Company
Abstract: A self adjusting bezel assembly for a display screen, and specifically for an infrared radiation touch input display system, including a method for assemblying the bezel apparatus to the display screen. An outer bezel is mounted in fixed relation to the display device, and an inner bezel containing a radiation emitter and detector matrix is retained by and floats with respect to the outer bezel for being urged against the display screen in precise relation thereto.
Type:
Grant
Filed:
March 23, 1989
Date of Patent:
February 6, 1990
Assignee:
Bell & Howell Publication Systems Company