Electronic blackboards date at least to the mid-1960s, when emphasis was placed on the communication of graphical data, specifically handwriting and sketches, from one location to another. Fisher et al. U.S. Pat. No. 3,706,850 discloses a system related to such activity.
At about the same time, graphic tablets that allowed the entry of line drawings into a computer were developed. Whetstone et al. U.S. Pat. No. 3,838,212 is an early example of developments in this area.
By the mid-1980s, a third kind of a product group was developed to address the need for a local hard copy of material written and sketched onto a dry-erase, so-called whiteboard. This generic group of systems, known collectively as electronic copy boards, relates fundamentally to stand-alone devices that have much in common with well known reducing photocopiers.
Each of these previously known devices attempts to provide the user with a communication medium that uses familiar writing tools. In the case of electronic blackboards and electronic copy boards, the medium is a fixed wall-mounted surface meant for mass viewing, in which marking or writing is accomplished by the use of colored markers, and in which erasing is accomplished by wiping the surface with an eraser. In the case of the graphic tablet, the medium is a desktop slate and stylus meant for individual use.
Those skilled in the art recognize that both electronic blackboards and electronic copy boards typically require dedicated, highly specialized surfaces and equipment structures. These specialized structures result in an immobile, cumbersome, and relatively expensive systems. Systems and approaches generally in this line of technical art are illustrated, for example, in Cecreman U.S. Pat. No. 3,613,066 (“Cecreman”), Garwin et al. U.S. Pat. No. 4,558,313 (“Garwin”), Hansen U.S. Pat. No. 4,506,354 (“Hansen”), Enokido U.S. Pat. No. 4,670,751 (“Enokido”), Miyamori U.S. Pat. No. 4,711,977 (Re. No. 33,936) (“Miyamori”), Mallicoat U.S. Pat. No. 4,777,329 (“Mallicoat '329”), Stefik et al. U.S. Pat. No. 4,814,552 (“Stefik”), Mallicoat U.S. Pat. No. 5,248,856 (“Mallicoat '856”), Murakami U.S. Pat. No. 5,023,408 (“Murakami”), and Wilson U.S. Pat. No. 5,434,370 (“Wilson”).
Cecreman discloses a display panel and means responsive to the positions and moves of a pointer on the panel to generate information signals for a computer. Thin, coherent light beams parallel to the surface of the panel are systematically and repetitively displaced in crossing relation to scan at least part of the surface. The position of a marker relative to the display panel is detected by interference of the marker with the scanned light beams.
Garwin focuses on an indicator-to-data processing interface which employs a light source and a background reflector as constituents in a system to monitor occlusion of light occurring from the positioning and movement of a manually moved indicator over a surface.
Enokido discloses an eraser for an electronic blackboard having a variable erasing area. The eraser includes a small area erasing unit and a detachable large area erasing unit. Detectors determine when the eraser contacts the board surface, and whether the small area erasing unit or the large area erasing unit are currently in use.
Miyamori discloses an electronic blackboard, writing instrument, and position-detecting control unit. The system uses magnetic bias to detect the position of a writing/erasing element relative to that of video information displayed on a writing surface.
Mallicoat '329 and Mallicoat '856 address graphic input systems that employ ultrasound (“Mallicoat '329”) or scanned light (“Mallicoat '856”) to monitor the position of a mobile element over a surface. Mallicoat '856 includes at least two spaced transceiver-structure stations that optically track the position and motion of a writer or eraser based upon bar code techniques. While Mallicoat '856 suggests that these transceiver-structure stations may be retrofitted to a conventional writing-surface structure, no discussion is provided for performing such retrofit. Further, it is unclear whether the scanning technology disclosed in Mallicoat '856 would be suitable for a retrofit application.
Stefik discloses an input device, or stylus, for entering hand drawn forms into a computer. In particular, Stefik describes a writing instrument, a pressure switch for determining whether the instrument contacts the writing surface, an acoustic transmitter for triangulating the position of the stylus on the surface, and a wireless transmitter for transmitting data and timing information to the computer. In operation, the stylus transmits an infrared signal and an ultrasound pulse. The system receives the infrared signal essentially immediately. Two microphones receive the ultrasound pulse after a delay that is a function of the speed of sound and the distance of the stylus from each microphone. Based on the received pulses, the system calculates the stylus position. Switches for indicating functions are mounted on the stylus. Multiple styluses can be used, each transmitting a distinctive identification code so that the system can determine which stylus is the signal source.
Murakami describes an electronic blackboard, including a sensing tablet which senses the position of a writing tool that includes a tuned circuit having a predetermined resonant frequency.
Wilson discloses a graphic data acquisition system in which a digitized record is produced according to the X, Y, and Z position of a writing implement relative to a writing surface. An expanse of electromagnetic radiation is generated in a zone adjacent to the writing surface, and an electromagnetic interactive pen interacts with such electromagnetic radiation to produce a signal that locates the pen relative to the writing surface.
Previously known apparatus also provide transcription systems that may be removably attached to a writing surface, such as a whiteboard. For example, Holtzman U.S. Pat. No. 6,266,051 (“Holtzman”) describes retrofittable apparatus for converting a substantially planar surface into an electronic data capture device, in which the components of the system are readily retrofittable to a wide variety of otherwise conventional writing-surface structures, such as whiteboards. Conventional triangulation techniques are used to track the position and motion of a writer or eraser. An encoding facility associated with the writing implement provides the ability to distinguish whether the writing implement is used for marking or erasing, and also may determine the nature or character of written line width or eraser swath. A data stream thus generated can be used in a variety of ways, such as for example, to feed information into the memory of a digital computer, and/or to feed information for transmission to remote stations.
Although the Holtzman system provides a useful solution to the problem of retrofitting an electronic data capture function to a writing surface, it is also desirable to provide a more permanent installation to a writing surface, such as a whiteboard, after manufacture and/or sale/use thereof, and thereby avoid such concerns as positioning, and calibration. It also would be desirable to provide an inexpensive system.
It further would be advantageous to provide electronic transcription systems that adapt a writing surface, such as standard whiteboard, for use with an electronic transcription system and also avoid the use of temporary fasteners and other such expedients.