Position detection system

• US 6,798,403 B2
• Filed: 10/23/2001
• Issued: 09/28/2004
• Est. Priority Date: 10/24/2000
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Watanabe, Kazuhiro, Kitada, Takashi
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): PIZIALI, JEFFREY J
• Application Number:
  US09/983,243
• Publication Number:
  US 20020047833A1
• Time in Patent Office: 1,071 Days
• Field of Search: 345/158, 345/162, 345/173, 345/175-183, 710/73, 178/18-1-, 178/18.09, 178/18.11, 178/19.01, 178/19.02, 178/19.05, 178/20-1-, 341/5, 250/227.13, 367/118, 367/119, 367/124, 367/126-129
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Abstract

A system for detecting a position of a stylus movable on an interactive board includes a position information transmitter and information detection sections. The stylus has the transmitter for transmitting to the detection sections electromagnetic wave signals or light signals, and ultrasonic wave signals. The position is detected based on measurement of direct distances for signal transmission between the stylus and the detection sections. The detected position information is output to a personal computer, image projector, printer, etc. Each detection section has an opening sized so that the ultrasonic waves are advantageously transmitted through the opening and substantially radially from its center to its piezoelectric element.

Claims

1. A coordinates detection system for detecting coordinates of an object movable to fixed detection means, said system comprising the fixed detection means, signal wave transmitter means and coordinates detection means, wherein:

said signal wave transmitter means is provided at said movable object and generates to transmit signals of electromagnetic wave and ultrasonic wave to said fixed detection means;

said fixed detection means comprises first and second detection means, said first detection means receiving and detecting a signal of electromagnetic wave transmitted from said transmitter means, and said second detection means detecting a signal of ultrasonic wave transmitted directly from said transmitter means;

said coordinates detection means detecting coordinates of a position of said movable object provided with said transmitter means by detecting a time difference between the detection of the transmitted waves of said first and said second detection means;

said second detection means defining an opening, the size of the opening being smaller than a detection element cone section of the second detection means, for passing therethrough to further transmit the transmitted signal of ultrasonic wave to said cone section by making the transmitted ultrasonic wave propagate radially from a center of opening to said cone section.

2. A coordinate detection system as claimed in claim 1, wherein said coordinate detection means includes amplification means having an amplification factor to be changed for amplification of the transmitted ultrasonic wave signal in dependence upon the detected coordinates of the object position.

3. A coordinate detection system as claimed in claim 1, wherein said coordinate detection means includes storage means for storing the detected coordinates of said movable object.

4. A coordinate detection system as claimed in claim 3, wherein said coordinate detection means selects a gain factor or a slice level for generation of a timing signal depending on position coordinates read out from said storage means.

5. A coordinate detection system as claimed in claim 2, wherein said coordinate detection means defines and partitions a coordinate space into a predetermined number of areas, said movable object being moved in said areas, said coordinate detection means include means for determining different gain factors depending on said areas.

6. A coordinate detection system as claimed in claim 2, wherein said coordinate detection means includes means for selectively applying a gain factor for the amplification of the signal of transmitted ultrasonic wave in dependence upon a position area in which said transmitter means exists.

7. A display system comprising:

board means and writing means movable thereon for generating to transmit signals of electromagnetic wave and ultrasonic wave, thereby transmitting information of a position of said writing means on said board;

first detection means for detecting a signal of electromagnetic wave transmitted from said writing means;

second detection means for detecting a signal of said ultrasonic wave transmitted from said writing means;

position detection means for detecting a position of said writing means on said board means based on signal detection results of said first detection means and said second detection means;

storage means for storing position information detected by said position detection means;

a computer having display means; and

transmission means for transmitting said position information stored in said storage means to said computer and enabling said display means based on the transmitted position information;

wherein

said second detection means defines an opening, the size of the opening being smaller than a detection element cone section of the second detection means, for passing to further transmit therethrough the transmitted signal of ultrasonic wave to said cone section by making the further transmitted ultrasonic wave propagate radially from a center of said opening to said cone section.

8. A display system as claimed in claim 7, further comprising reading means for reading images at least written on said board means.

9. A display system as claimed in claim 8, further comprising output means for outputting information at least of said images read by said reading means.

10. A display system as claimed in claim 7, further including means for executing PC operations for switching of images displayed on said display means from said board means by operating said writing means.

11. A display system as claimed in claim 7, wherein letters can be written on said board means even if said writing means is one having marking function.

12. A display system as claimed in claim 7, further comprising conveying means for conveying drawing means.

13. A display system as claimed in claim 8, further comprising data sending means for sending data obtained by said reading means to said computer.

14. A position detection system comprising:

signal transmitter means for generating to transmit an ultrasonic wave;

detection means, having a detection element cone section, for detecting the ultrasonic wave transmitted from said transmitter means, said detection means having means for defining an opening to make the transmitted ultrasonic wave pass therethrough for further transmission for the detection of the transmitted ultrasonic wave, said opening having a size smaller than that of said detection element cone section to make the further transmitted ultrasonic wave propagate radially from a center of said opening to said detection element cone section; and

position detection means for detecting a position of said transmitter means based on a detection result of the detection means.

15. A position detection system comprising:

signal transmitter means for generating to transmit an ultrasonic wave;

detection means for detecting an ultrasonic wave transmitted from said transmitter means;

means for defining an opening to make an ultrasonic wave transmitted from said transmitter means pass through said opening for further transmission to said detection means, said opening having a size smaller than that of a detection element cone section of said detection means to make the further transmitted ultrasonic wave propagate radially from a center of said opening to said detection element cone section; and

position detection means for detecting a position of said transmitter means based on a detection result of the detection means.

16. A position detection system comprising:

signal transmitter means for generating to transmit an electromagnetic wave and an ultrasonic wave;

first detection means for detecting the electromagnetic wave generated from said transmitter means;

second detection means for detecting the ultrasonic wave transmitted from said transmitter means, said second detection means having means for defining an opening to make the transmitted ultrasonic wave pass therethrough for further transmission for the detection of the transmitted ultrasonic wave by said second detection means, said opening having a size smaller than that of a detection element cone section of said second detection means to make the further transmitted ultrasonic wave propagate radially from a center of said opening; and

position detection means for detecting a position of said transmitter means based on detection results of said first and second detection means.

17. The system of claim 16, wherein said electromagnetic wave is a light wave.

18. A position detection system as claimed in claim 16, wherein said transmitter means generate to transmit sequential light signals as the electromagnetic wave signal and wherein said first detection means receives a first light signal and thereafter a second light signal.

19. A position detection system as claimed in claim 18, further including a display and color designation means for detecting a time difference between said first light signal and said second light signal received by said first detection means in order to designate a color display of the detected position.

20. A position detection system as claimed in claim 16, said transmitter means transmits said electromagnetic wave and said ultrasonic wave simultaneously.

21. A position detection system as claimed in claim 16, wherein said first detection means and said second detection means are provided with means for generating timing signals.

22. A position detection system as claimed in claim 16, wherein said second detection means includes amplification means for receiving and amplifying the transmitted ultrasonic wave signal.