Marking device for electronic presentation board

• US 6,292,177 B1
• Filed: 03/05/1997
• Issued: 09/18/2001
• Est. Priority Date: 03/05/1997
• Status: Expired due to Term

• Current Assignee: All Quality and Services, Inc., Pegasus Technologies (GE Aerospace), Luidia Incorporated (Luidia Global Co., Ltd.), Pnf Co., Ltd.
• Original Assignee: Tildenet, Inc.
• Inventors: Zloter, Isaac, Holtzman, Rafi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Nguyen, Jimmy H.
• Application Number:
  US08/811,947
• Time in Patent Office: 1,658 Days
• Field of Search: 345/173-180, 345/18-1-, 345/19-1-
• US Class Current: 345/173
• CPC Class Codes: G06F 3/043 using propagating acoustic waves

Abstract

A presentation board digitizer system for large boards preferably employs at least three spaced-apart ultrasound receivers assemblies. A current position of an ultrasound transmitter is assigned as a weighted centroid of time-of-flight position measurements based on at least two pairs of receiver assemblies. The weighting used varies as a function of the transmitter across the board. A preferred structure of an ultrasound receiver assembly for use in the system employs a pair of ultrasound receivers arranged side-by-side in a line perpendicular to the surface of the presentation board. The receives are connected so as to generate a total output signal corresponding to the instantaneous sum of the ultrasound signals received at each, such that the receiver assembly is most sensitive to ultrasound signals incident from a plane adjacent to the presentation board. Also described are a transmitter device for use with a conventional pen in which the ultrasound transmitter is a cylindrical element lying coaxial with the pen and adjacent to its tip, and a jointed eraser structure.

Claims

1. A narrow-band eraser device for use with a presentation board digitizer system including a presentation board, a first receiver and a second receiver, the narrow-band eraser device comprising:

(a) a handle connected by a pressure-sensitive element to

(b) an eraser element having a substantially flat eraser surface of a narrow rectangular shape comprised of a first end and a second end; and

(c) a collection of contact microswitches consisting essentially of a first microswitch controlling a first transmitter device located substantially at said first end and a second microswitch controlling a second transmitter device located substantially at said second end;

wherein when a first portion of said eraser surface proximate to said first end contacts the presentation board, said first microswitch activates said first transmitter device to present to said receivers an indication that said first portion is in contact with said presentation board;

wherein when a second portion of said eraser surface proximate to said second end contacts the presentation board, said second microswitch activates said second transmitter device to present to said receivers an indication that said second portion is in contact with said presentation board; and

wherein said pressure-sensitive element identifies to said presentation board digitizer system when at least a portion of said eraser surface contacts said presentation board.

2. The narrow-band eraser device of claim 1,

wherein said first transmitter device is comprised of a first infra-red transmitter and a first ultrasound transmitter, both transmitters activated by said first microswitch; and

wherein said second transmitter device is comprised of a second infra-red transmitter and a second ultrasound transmitter, both transmitters activated by said second microswitch;

wherein said first receiver and said second receiver are responsive to ultrasound received from at least one of said ultrasound transmitters; and

wherein said presentation board digitizer system is further comprised of a third receiver responsive to infra-red radiation received from at least one of said infrared transmitters.

3. The narrow-band eraser device of claim 2,

wherein each of said ultrasound transmitters is further comprised of a cylindrical ultrasound transmitter located in said handle, an ultrasound conductor tube going from said handle to said eraser element directing an ultrasound sound from said cylindrical ultrasound transmitter toward a reflector cone reflecting said ultrasound sound.

4. The narrow-band eraser device of claim 2,

wherein each of said infrared transmitters is located in said handle;

and

wherein each of said infrared transmitters emits infrared radiation to an associated infrared reflector located in said handle;

wherein each of said associated infrared reflectors reflect infrared radiation emitted by said infrared transmitters.

5. The narrow-band eraser device of claim 4,

wherein said first infrared transmitter is further located substantially at said first end;

and

wherein said second infrared transmitter is further located substantially at said second end.

6. The narrow-band eraser device of claim 1,

wherein said pressure-sensitive element includes a touch switch;

wherein when at least a portion of said eraser surface contacts said presentation board, a signal is transmitted to said touch switch enabling said pressure-sensitive element to identify said contact to said presentation board digitizer system.

7. The narrow-band eraser device of claim 6,

wherein said touch switch is further comprised of a printed circuit board and electrical circuitry enabling said touch switch to identify when said eraser surface is contacting said presentation board.