US5570299A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coordinate input apparatus, vibration sensing device and method of evaluating same
Assignee: Canon Inc
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Filing: 1993-08-26
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Granted: 1996-10-29
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Expires: 2013-08-26
Abstract
Abstract Vibration applied to a tablet is sensed by a sensor provided on the tablet and a time delay from generation of the vibration to the sensing thereof is measured, whereby distance from the vibration source to the sensor can be measured. If the vicinity of the leading edge of the envelope of registration is sensed when sensing the vibration, the effects of reflected waves from the periphery of the tablet are reduced. To this end, the envelope is differentiated to detect an inflection point. The peak gain frequency of the differentiating circuit is greater than the frequency of vibration generated by the vibration source. As a result, the phase of the output signal produced by the differentiating circuit is advanced by about π/2 with respect to the phase of the input signal, thereby making it possible to sense vibration more quickly.
Inventors
- 👤 Masaki Tokioka
- 👤 Atsushi Tanaka
- 👤 Yuichiro Yoshimura
- 👤 Kiyoshi Kaneko
- 👤 Ryozo Yanagisawa
- 👤 Katsuyuki Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:25
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/043; G06F3/0433
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
184 words
A coordinate input apparatus, comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having a differentiating circuit for detecting a specific point in the envelope signal, wherein said differentiating circuit adopts a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiates the envelope signal at least one time and obtains a first zero-cross point which serves as the specific point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the specific point by said detecting means; and calculating means for calculating a distance between said vibration pen and said vibration sensing means based on the time measured by said measuring means, and for calculating a coordinate of a position of said vibration pen on said tablet based upon the calculated distance.
Claim 2
Dependent Claim
184 words
A coordinate input apparatus, comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having a differentiating circuit for detecting a specific point in the envelope signal, wherein said differentiating circuit adopts a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiates the envelope signal at least one time and obtains a first zero-cross point which serves as the specific point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the specific point by said detecting means; and calculating means for calculating a distance between said vibration pen and said vibration sensing means based on the time measured by said measuring means, and for calculating a coordinate of a position of said vibration pen on said tablet based upon the calculated distance.
Claim 3
Dependent Claim
70 words
The apparatus according to claim 1, wherein said generating means has a higher-order frequency filter for enlarging pass loss of a frequency higher than a cut-off frequency in order to enlarge the difference between amplitude transmission characteristics of a frequency of the envelope signal and a center frequency, and to prevent said differentiating circuit from outputting a signal having same waveform as the signal sensed by said vibration sensing means.
Claim 4
Dependent Claim
27 words
The apparatus according to claim 1, wherein said detecting means detects an inflection point of said envelope as the specific point by differentiating the envelope signal twice.
Claim 5
Dependent Claim
23 words
The apparatus according to claim 1, wherein said vibration pen generates vibration at a prescribed period in synchronism with said vibration sensing means.
Claim 6
Dependent Claim
32 words
The apparatus according to claim 1, further comprising display means for displaying an image, wherein said vibration transmitting means includes a transparent plate, said display means being provided beneath said transparent plate.
Claim 7
Dependent Claim
24 words
The apparatus according to claim 5, wherein a plurality of said vibration sensing means are provided at mutually different positions on said transparent plate.
Claim 8
Dependent Claim
28 words
The apparatus according to claim 1, wherein said detecting means detects a peak point of the envelope signal as the specific point by differentiating the envelope signal once.
Claim 9
Dependent Claim
71 words
The apparatus according to claim 7, wherein said generating means has a higher-order frequency filter for enlarging pass loss of a frequency higher than a cut-off frequency in order to enlarge the difference between amplitude transmission characteristics of a frequency of the envelope signal and a center frequency, and to prevent said differentiating circuit from outputting a signal having the same waveform as the signal sensed by said vibration sensing means.
Claim 10
Dependent Claim
23 words
The apparatus according to claim 7, wherein said vibration pen generates vibration at a prescribed period in synchronism with said vibration sensing means.
Claim 11
Dependent Claim
32 words
The apparatus according to claim 7, further comprising display means for displaying an image, wherein said vibration transmitting means includes a transparent plate, said display means being provided beneath said transparent plate.
Claim 12
Dependent Claim
24 words
The apparatus according to claim 10, wherein a plurality of said vibration sensing means are provided at mutually different positions on said transparent plate.
Claim 13
Dependent Claim
181 words
A coordinate input apparatus comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having two serially-connected differentiating circuits for detecting an inflection point in the envelope signal, wherein said two serially-connected differentiating circuits adopt a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiate the envelope signal, and obtain a first zero-cross point which serves as the inflection point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the specific point by said detecting means; and calculating means for calculating a distance between said vibration pen and said sensing means based on the time measured by said measuring means, and calculating a coordinate of a position of said vibration pen in said tablet based upon the calculated distance.
Claim 14
Dependent Claim
181 words
A coordinate input apparatus comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having two serially-connected differentiating circuits for detecting an inflection point in the envelope signal, wherein said two serially-connected differentiating circuits adopt a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiate the envelope signal, and obtain a first zero-cross point which serves as the inflection point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the specific point by said detecting means; and calculating means for calculating a distance between said vibration pen and said sensing means based on the time measured by said measuring means, and calculating a coordinate of a position of said vibration pen in said tablet based upon the calculated distance.
Claim 15
Dependent Claim
246 words
A coordinate input apparatus comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having two serially-connected differentiating circuits for detecting an inflection point in the envelope signal, wherein said two serially-connected differentiating circuits adopt a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiate said envelope signal, and obtain a first zero-cross point which serves as the inflection point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the inflection point by said detecting means; and calculating means for calculating a distance between said vibration pen and said sensing means based on the time measured by said measuring means, and a coordinate of a position of said vibration pen in said tablet based upon the calculated distance, wherein said generating means has a higher-order frequency filter for enlarging pass loss of a frequency higher than a cut-off frequency in order to enlarge the difference between the amplitude transmission characteristics of a frequency of the envelope signal and a center frequency, and to prevent said differentiating circuits from outputting a signal having the same waveform as the signal sensed by said vibration sensing means.
Claim 16
Dependent Claim
246 words
A coordinate input apparatus comprising: a tablet for transmitting vibration; a vibration pen for applying vibration to said tablet; a plurality of vibration sensing means for sensing vibration transmitted by said tablet; generating means for generating an envelope signal based on the vibration sensed by said vibration sensing means; detecting means having two serially-connected differentiating circuits for detecting an inflection point in the envelope signal, wherein said two serially-connected differentiating circuits adopt a frequency the same as or higher than that of the vibration applied by said vibration pen as peak gain frequency, differentiate said envelope signal, and obtain a first zero-cross point which serves as the inflection point; measuring means for measuring time from the application of the vibration from said vibration pen to said tablet to the detection of the inflection point by said detecting means; and calculating means for calculating a distance between said vibration pen and said sensing means based on the time measured by said measuring means, and a coordinate of a position of said vibration pen in said tablet based upon the calculated distance, wherein said generating means has a higher-order frequency filter for enlarging pass loss of a frequency higher than a cut-off frequency in order to enlarge the difference between the amplitude transmission characteristics of a frequency of the envelope signal and a center frequency, and to prevent said differentiating circuits from outputting a signal having the same waveform as the signal sensed by said vibration sensing means.
References Cited (Backward Citations)
EP0169538A2
Cited
US4665282A
Cited
US4931965A
Cited
EP0423843A2
Cited
JPH01236320A
Cited
JPH02125322A
Cited
JPH02130614A
Cited
JPH02130612A
Cited
JPH02130616A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-10-29 | 2000-04-29 | 2000-10-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-29 | 2004-04-29 | 2004-10-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-29 | 2008-04-29 | 2008-10-29 | $7700.00 | Window Closed / Lapsed |