EP0484160A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Position and function input system for a large area display
Assignee: Xerox Corp
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Filing: 1991-10-31
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Granted: —
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Expires: 2011-10-31
Abstract
Abstract An input device for simultaneously entering position and function information into an electronic system having a viewing surface (20) upon which is displayed information generated by the electronic system. A light pen (22) is provided for projecting a light spot onto the viewing surface for indicating the position of a location marker thereon and for indicating a function to be performed. The optical output of the light pen is modified to represent the selected function. A sensor (28) receives the light spot and, in conjunction with discrimination electronics, determines the location of the centroid of the light spot relative to the viewing surface, and determines the function to be performed.
Inventors
- 👤 Scott A. Elrod
- 👤 John Tang
- 👤 Scott L. Minneman
- 👤 Warren B. Jackson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 15:32
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/042; G06F3/0425; G06F3/033; G06F3/038; G06F3/0386
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
118 words
An input system for simultaneously entering position and function information into an electronic system comprising a viewing surface (20), means (12) for displaying said information upon said viewing surface, a source of illumination (22), means for projecting said source of illumination as a light spot upon one side of said viewing surface, means (Fig. 4) for modifying the illumination of said light spot so as to represent a function to be performed, and means (28) for sensing the light spot and for generating output signals representative of both the centroid of said light spot upon said viewing surface and the function to be performed, said means for sensing being located on the opposite side of said viewing surface.
Claim 2
Dependent Claim
33 words
An input system as defined in claim 1, wherein said means for modifying comprises means (54) for chopping said source of illumination at a frequency in accordance with said function to be performed.
Claim 3
Dependent Claim
32 words
An input system as defined in claim 1 or claim 2, wherein said means for modifying comprises means for generating an optical digital code in accordance with said function to be performed.
Claim 4
Dependent Claim
22 words
An input system as defined in any one of the preceding claims, wherein said means for sensing comprises a position sensing photodiode.
Claim 5
Dependent Claim
25 words
An input system as defined in claim 4, further comprising a lens (24) for focusing substantially said entire viewing surface upon said position sensing photodiode.
Claim 6
Dependent Claim
35 words
An input system as defined in any one of the preceding claims, wherein said means for displaying information projects a location marker on said viewing surface substantially located at the centroid of said light spot.
Claim 7
Dependent Claim
31 words
An input system as defined in any one of the preceding claims, wherein said source of illumination projects infra-red light and said means for sensing is sensitive to said infrared light.
Claim 8
Dependent Claim
28 words
An input system as defined in claim 7 when appended to claim 5, further comprising an infrared filter (26) located between said lens and said position sensing photodiode.
Claim 9
Dependent Claim
31 words
An input system as defined in any one of the preceding claims, wherein said means for projecting is wireless and includes a self-contained power source (32) for said source of illumination.
Claim 10
Independent Claim
99 words
A method of simultaneously entering position and function information into an electronic system comprising the steps of providing a viewing surface, displaying said information upon said viewing surface, providing a source of illumination, projecting said source of illumination as a light spot upon one side of said viewing surface, modifying the illumination of said light spot so as to represent a function to be performed, sensing the relative position of said light spot upon said viewing surface, and generating signals representative of both the centroid of said light spot upon said viewing surface and the function to be performed.
Claim 11
Dependent Claim
54 words
A method as defined in claim 10, further comprising the steps of projecting said light spot upon a sensor located on the opposite side of said viewing surface and interpreting said generated signals for displaying a location marker substantially at the centroid of said light spot and for invoking the function to be performed.
Claim 12
Dependent Claim
32 words
A method as defined in claim 10 or claim 11, wherein said step of modifying comprises chopping said source of illumination at a frequency in accordance with said function to be performed.
Claim 13
Dependent Claim
151 words
An input system for simultaneously entering position and function information into an electronic system from a plurality of sources, comprising a viewing surface (20), means (12) for displaying said information upon said viewing surface, a plurality of unique sources of illumination (22), the optical output of each identifying the source and identifying a function to be performed, means for projecting each of said sources of illumination as a light spot upon one side of said viewing surface, means (28) for sensing said light spots upon said viewing surface and for generating output signals representative of said light spots, said means for sensing being located on the opposite side of said viewing surface, and means for receiving said output signals and for generating signals representative of the locations of the centroids of each of said light spots relative to said viewing surface and signals representative of the identified functions to be performed.
Claim 14
Dependent Claim
69 words
An input system as defined in claim 13, wherein the optical output of each of said unique sources of illumination comprises means (54) for chopping said source of illumination into a group of frequencies closely clustered about a mean frequency, wherein each frequency is representative of a function to be performed (Fig. 3), said groups of frequencies being distinguishable from one another by electronic filtering of said mean frequencies.
Claim 15
Dependent Claim
53 words
An input system as defined in claim 14 wherein each of said means for chopping comprises a crystal oscillator (58, 60, 62) having a resonant frequency which establishes a clock frequency, and means (66, 68, 70) for dividing said clock frequency into a desired count in response to said function to be performed.
Claim 16
Dependent Claim
43 words
An electronic system as defined in any one of claims 13 to 15, wherein said means for receiving said output signals and for generating signals comprises a plurality of bandpass filters, each capable of passing only a single group of closely clustered frequencies.
Claim 17
Dependent Claim
47 words
An electronic system as defined in any one of claims 13 to 15, wherein said means for receiving said output signals and for generating signals comprises frequency-to-voltage converters and means for comparing said voltages with reference voltages for generating signals indicative of said functions to be performed.
Claim 18
Dependent Claim
60 words
An electronic system as defined in claim 13, wherein said means for sensing is a position sensing photodiode which generates a number of current signals in response to the light intensity and position of the centroids of said light spots projected thereon, each of said signals comprising a superposition of square waves at said frequencies of said sources of illumination.
References Cited (Backward Citations)
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