Color and brightness tracking in a cathode ray tube display system
First Claim
1. Color and brightness tracking control apparatus for a color cathode ray tube display instrument system subjected to viewing under a wide range of ambient light conditions comprising(a) a cathode ray tube having a display screen for emitting images in a plurality of different colors dependent upon the independent and variable energization of cathode means for producing at least two independent primary colors the relative brightnesses of which determine said plurality of colors,(b) video command means for commanding at least one image to be displayed in at least one predetermined color comprised of components of said two primary colors at the required relative brightness levels,(c) ambient light sensor means for providing a signal corresponding to the range between the extremes of ambient light conditions existing in the vicinity of said display instrument,(d) computer means including(i) memory means containing data representing the independent cathode energizations required to produce each of said primary color component relative brightnesses over said range of ambient light conditions, and(ii) processor means responsive at least in part to said light sensor means for continuously computing a reference display brightness and for deriving from said memory means cathode energization data required to produce said two primary color component relative brightnesses at the existing ambient light conditions, and(e) means responsive to said video command means and said derived cathode energization data for energizing said cathode means to thereby produce said predetermined color image at the existing ambient light conditions.
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Accused Products
Abstract
A color cathode ray tube display apparatus particularly for use under a wide range of ambient light conditions, such as in an aircraft cockpit, wherein each of the primary color phosphors has a unique brightness versus cathode drive characteristic, which characteristic also is dependent upon whether the displayed information is raster written or stroke written and wherein such characteristics also may vary from tube to tube. The output of at least one cockpit ambient light sensor in addition to a pilot selected brightness is used on a continuous basis to calculate a reference brightness level for the sensed ambient brightness conditions and display writing mode, this reference brightness level being used to calculate the corresponding brightness level for each of the primary color components of the commanded symbology color and concomitant drive voltages to the CRT'"'"'s cathode or cathodes. The operation and ambient brightness calculations are preferably performed by a microprocessor and associated personality PROM containing the color/brightness characteristics of the particular cathode ray tube to which it is dedicated. The computations used are preferably logarithmic as is the data whereby not only to simplify calculations but more importantly to correspond to the normal logarithmic reception characteristics of the human eye.
359 Citations
12 Claims
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1. Color and brightness tracking control apparatus for a color cathode ray tube display instrument system subjected to viewing under a wide range of ambient light conditions comprising
(a) a cathode ray tube having a display screen for emitting images in a plurality of different colors dependent upon the independent and variable energization of cathode means for producing at least two independent primary colors the relative brightnesses of which determine said plurality of colors, (b) video command means for commanding at least one image to be displayed in at least one predetermined color comprised of components of said two primary colors at the required relative brightness levels, (c) ambient light sensor means for providing a signal corresponding to the range between the extremes of ambient light conditions existing in the vicinity of said display instrument, (d) computer means including (i) memory means containing data representing the independent cathode energizations required to produce each of said primary color component relative brightnesses over said range of ambient light conditions, and (ii) processor means responsive at least in part to said light sensor means for continuously computing a reference display brightness and for deriving from said memory means cathode energization data required to produce said two primary color component relative brightnesses at the existing ambient light conditions, and (e) means responsive to said video command means and said derived cathode energization data for energizing said cathode means to thereby produce said predetermined color image at the existing ambient light conditions.
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11. Color and brightness tracking control apparatus for a color cathode ray tube display instrument system subjected to viewing under a wide range of ambient light conditions comprising
(a) a cathode ray tube having a display screen for emitting images in a plurality of different colors dependent upon the individual and variable energization of cathode means for producing at least three individual primary colors the relative brightnesses of which determine said plurality of colors, (b) video command means for commanding a predetermined plurality of colors in which a plurality of images are to be displayed, each of said colors comprising a plurality of predetermined components of said primary colors at predetermined relative brightness levels, (c) ambient light sensor means for providing a signal which varies in accordance with the extremes of ambient light intensities existing in the vicinity of said display instrument, (d) digital computer means including (i) memory means containing data representing the individual cathode energization required to produce each of said primary color component relative brightness levels required to produce each of said predetermined plurality of colors over said range of ambient light intensity conditions, and (ii) processor means responsive at least in part to said light sensor means for continuously computing a reference display brightness dependent upon the existing ambient light intensity conditions and for deriving from said memory means the cathode energization data required to produce each of said predetermined plurality of colors at the existing ambient light intensity conditions, and (e) means responsive to said video command means and said derived cathode energization data for energizing said cathode means to thereby produce said predetermined plurality of color images at the existing ambient light intensity conditions.
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12. A method of operating a color cathode ray tube (CRT) display instrument, which is viewable under a wide range of ambient light conditions, with the aid of a digital computer, comprising
(a) providing said computer with a stored data base peculiar to said CRT display including at least a plurality of cathode drive excitations required to produce a corresponding plurality of brightnesses of each of the CRT'"'"'s primary color emissions, (b) constantly measuring the ambient light conditions in the vicinity of said display, (c) constantly providing the computer with said ambient light measure, (d) repetitively calculating in the computer at a rate substantially greater than the refresh rate of said CRT display, a reference display brightness compatible with said ambient light conditions, and (e) repetitively extracting from said data base at said calculation rate a cathode drive excitation corresponding to the brightness of each color component emission for the existing ambient light conditions.
Specification