Ambient-light-responsive touch screen data input method and system
First Claim
1. A touch screen system comprising:
- first and second photosensor units,each of said photosensor units having a front and a rear,means for mounting said units proximate to but outside of first and second successive corners, respectively, of a touch screen area and facing toward said touch screen area,a line scanner array of closely spaced photoresponsive elements in the rear of each of said units,a wide angle viewing lens assembly in the front of each of said units having a lateral field of view spanning said touch screen area for transmitting light from said lateral field of view with limited height above said touch screen area onto said line scanner array in the rear of the respective unit for activating at least one of said photo-responsive elements in each line scanner array with said touch screen area being substantially uniformly illuminated by a significant amount of ambient light when a pointer is brought near to a point in said touch screen area causing a change in light intensity at said point as viewed by said first and second units along first and second lines of vision, respectively, to said point, andcalculating means connected to the line scanner array of photo-responsive elements in each of said photosensor units for determining;
(a) the angle "A" between said first line of vision and a straight line of length "D" extending from near said first corner to near said second corner,(b) the angle "B" between said second line of vision and said straight line of length D,(c) the cotangent of angle A and the cotangent of angle B,(d) calculating the distance "Y" along a perpendicular line extending from said straight line to said point by dividing said length D by the sum of CtnA plus CtnB, and(e) calculating the distance "X" from said first corner to said perpendicular line of multiplying the value of Y times CtnA.
1 Assignment
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Accused Products
Abstract
A convenient predetermined rectangular passive area is converted into a touch screen suitable for feeding X and Y cartesian coordinate data into a computer by employing ambient light as the medium to sense positioning of a pointer brought near to any desired coordinate location of the touch screen. Such "pointer" can be a stylus, rod, dowel, finger, pencil, or similar relatively long, slim element readily movable by hand and capable of reflecting a significant proportion of incident ambient light or of creating sharp shadows. The passive area can be any selected rectangular area of suitable size in space or in the air, or on or near an inert panel of plywood, hardboard, sheetrock, or flat wall, etc., or in a region located before a video or tracking screen, selection chart or informational items, for example, a passive custom keyboard. When the pointer comes near this touch screen, respective rays of its reflected or shadowed ambient light enter at least two optical sensing units mounted proximate to (but outside of) at least two adjacent corners of the touch screen. Each unit concentrates a field of vision spanning the screen area, with limited height, onto a line array of photosensors to interpret the angles A and B of detected changes in light intensity levels. X and Y are then determined by intersection of angles A and B using trigonometric procedures. The rugged touch screen method and system advantageously work over wide ranges of sizes of rectangular areas.
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Citations
21 Claims
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1. A touch screen system comprising:
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first and second photosensor units, each of said photosensor units having a front and a rear, means for mounting said units proximate to but outside of first and second successive corners, respectively, of a touch screen area and facing toward said touch screen area, a line scanner array of closely spaced photoresponsive elements in the rear of each of said units, a wide angle viewing lens assembly in the front of each of said units having a lateral field of view spanning said touch screen area for transmitting light from said lateral field of view with limited height above said touch screen area onto said line scanner array in the rear of the respective unit for activating at least one of said photo-responsive elements in each line scanner array with said touch screen area being substantially uniformly illuminated by a significant amount of ambient light when a pointer is brought near to a point in said touch screen area causing a change in light intensity at said point as viewed by said first and second units along first and second lines of vision, respectively, to said point, and calculating means connected to the line scanner array of photo-responsive elements in each of said photosensor units for determining; (a) the angle "A" between said first line of vision and a straight line of length "D" extending from near said first corner to near said second corner, (b) the angle "B" between said second line of vision and said straight line of length D, (c) the cotangent of angle A and the cotangent of angle B, (d) calculating the distance "Y" along a perpendicular line extending from said straight line to said point by dividing said length D by the sum of CtnA plus CtnB, and (e) calculating the distance "X" from said first corner to said perpendicular line of multiplying the value of Y times CtnA. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 19)
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12. Touch screen apparatus comprising:
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a pair of photosensor units adapted to be mounted proximate to but outside of a pair of successive corners of a passive touch screen area substantially uniformly significantly illiminated by ambient light, each of said photosensor units having a front and a rear, each of said units including mounting means for mounting the respective unit stationary with the front of the unit facing toward said touch screen area, a light scanner array of closely spaced photo-responsive elements in the rear of each of said units, a wide angle viewing lens assembly in the front of each of said units intended to face toward said touch screen area, and each of said wide angle viewing lens assemblies being adapted for transmitting light from a lateral field of vision spanning said touch screen area and with limited height above said touch screen area onto the line scanner array in the rear of the respective unit for activating at least one of said photo-sensitive elements when a pointer is brought near to any point of said touch screen area substantially uniformly significantly illuminated by ambient light. - View Dependent Claims (13, 14)
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15. The method for converting a two-dimensional rectangular area into a touch screen comprising the steps of:
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preselecting a conveniently located rectangular area being substantially uniformly illuminated by ambient light, said rectangular area being defined by successive first, second, third and fourth boundaries, positioning a first line scanner array of closely spaced photo-responsive elements proximate to but outside of a first corner of said rectangular area, said first corner being at the junction of said first and second boundaries, facing said first line array of photosensors toward said rectangular area, orienting said first line array of photosensors generally perpendicular to a first straight line about bisecting the included angle of said first corner, focusing light from a field of vision spanning between the whole of said first and second boundaries with limited height away from said area onto said first line scanner array of photo-responsive elements, positioning a second line scanner array of closely spaced photo-responsive elements proximate to but outside of a second corner of said rectangular area, said second corner being at the junction of said second and third boundaries, facing said second line array of photosensors toward said rectangular area, orienting said second line array of photosensors generally perpendicular to a second straight line about bisecting the included angle of said second corner, focusing light from a field of vision spanning between the whole of said second and third boundaries with limited height away from said area onto said second line scanner array of photo-responsive elements, using said first array for determining the angle "A" of the direction from said first array to a change in light intensity level at a point within said rectangular area caused by a pointer oriented generally perpendicular to said two-dimensional rectangular area and brought near to said point, said angle "A" being determined relative to said second boundary, using said second array for determining the angle "B" of the direction from said second array to a change in light intensity level at said point, said angle "B" being determined relative to said second boundary, calculating the cotangent of angle A relative to said second boundary, calculating the cotangent of angle B relative to said second boundary, calculating the perpendicular distance "Y" from said second boundary to said point by using the quotient of the length "D" along said second boundary between said first and second corners divided by the sum of the cotangent of angle A and the cotangent of angle B, and calculating the perpendicular distance "X" from said first boundary to said point by multiplying the value of Y times the cotangent of angle A, thereby employing ambient light for converting a two-dimensional rectangular area into a touch screen for determining the X and Y coordinates of any point within said area to which is brought a pointer oriented generally perpendicular to said area. - View Dependent Claims (16, 17, 18)
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20. A touch screen system comprising:
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at least a first and a second photosensor unit; each of said photosensor units having a front and a rear; means for mounting said photosensor units proximate to but outside of at least first and second corners, respectively, of a touch screen area with said front of the respective photosensor unit facing toward said touch screen area and with said photosensor units being spaced apart by a convenient distance "D" and with said photosensor units being located near opposite ends of a straight line extending between said first and second corners; each of said photosensor units having a line scanner array of closely spaced photoresponsive elements in the rear thereof; each of said photosensor units having wide angle viewing lens means in the front thereof having a lateral field of viewing spanning said touch screen area for transmiting light from said touch screen area onto said line scanner array in the rear thereof; said touch screen area being substantially uniformly illuminated by a significant amount of ambient light; calculating means connected to said line scanner array of photoresponsive elements in each of said first and second photosensor units; said calculating means including data input means for initial input of the size of said convenient distance "D"; and said calculating means being adapted for using trigonometric relationships related to the size of said convenient distance "D" and related to said straight line for calculating coordinates "X" and "Y" of a point in said touch screen area near to which is brought a pointer causing a change in light intensity at said point. - View Dependent Claims (21)
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Specification