Source: https://patents.google.com/patent/US7486809?oq=5%2C666%2C293
Timestamp: 2018-06-23 14:39:56
Document Index: 350487054

Matched Legal Cases: ['art) 30', 'art 30', 'art 30', 'art 30', 'art 30', 'art 30']

US7486809B2 - Capacitance detection device, fingerprint sensor, biometric authentication device, and method for searching capacitance detection condition - Google Patents
Capacitance detection device, fingerprint sensor, biometric authentication device, and method for searching capacitance detection condition Download PDF
US7486809B2
US7486809B2 US11041265 US4126505A US7486809B2 US 7486809 B2 US7486809 B2 US 7486809B2 US 11041265 US11041265 US 11041265 US 4126505 A US4126505 A US 4126505A US 7486809 B2 US7486809 B2 US 7486809B2
US11041265
US20050179446A1 (en )
With a related art fingerprint sensor, a detection circuit for reading out information of ridges and valleys of a fingerprint is formed on a single-crystalline silicon substrate. See, for example, Japanese Unexamined Patent Publication Nos. 11-118415, 2000-346608, 2001-56204, and 2001-133213. However, since a fingerprint sensor needs to have a size of around 20 mm×20 mm as required for its use, the fingerprint sensor formed on a single-crystalline silicon becomes costly. To solve this problem, a fingerprint sensor using a thin film metal-insulator-semiconductor (MIS) device has been proposed. See, for example, Japanese Unexamined Patent Publication No. 2003-254706. By using a thin film MIS device, a fingerprint sensor can also be formed on a glass substrate or a plastic substrate.
FIG. 1 shows an exemplary circuit diagram of the fingerprint sensor 1. The fingerprint sensor 1 mainly includes a data line driver 10 for selecting the data lines 37, a scanning line driver 20 for selecting the scanning lines 36, a fingerprint detection part (an active matrix part) 30 in which the above-described capacitance detection circuits 30 are arranged in a matrix, and an amplifier circuit 40 for amplifying the detection signals output from the capacitance detection circuits 31. In the fingerprint detection part 30, the capacitance detection circuits 31 are arranged in a matrix (n rows×m columns), wherein n scanning lines 36 and n low-potential power supply lines 39 are wired in a row direction, while m data lines 37 are wired in a column direction. The data line driver 10 is composed of a shift resistor 11 which generates a timing signal for selecting the data line 37 when successively driven at an analog point, a buffer 13, the analog switch 14 for selecting the data lines 37, and further, an adjustment control circuit 12 for selecting only a specific data line which is predetermined at a time of searching for fingerprint detection conditions. The scanning line driver 20 is composed of the buffer 23 and the shift resistor 21 which generates a timing signal for successively selecting the scanning line 36.
In the exemplary embodiment, the search for the fingerprint detection condition can be carried out in a short period of time, since it is not necessary to search all the n×m capacitance detection circuits 31 arranged in the fingerprint detection part 30 but needs only to search n capacitance detection circuits 31 connected with the specific data line 37 in order to obtain the optimal fingerprint detection condition. Consequently, it is possible to reduce the total time required for the fingerprint detection including the time to search for the fingerprint detection condition, whereby high-speed sensing and low electric consumption become possible. However, in order to reduce the time required for preparation for search for the fingerprint detection condition, it is necessary that the driving speed of the scanning line driver 20 be as high as that of the data line driver 10 (to be described in detail later).
In the embodiment, the search for the fingerprint detection condition can be carried out in a short period of time, since it is not necessary to search all the n×m capacitance detection circuits 31 arranged in the fingerprint detection part 30 but needs only to search m capacitance detection circuits 31 that are connected with the specific scanning line 36 in order to obtain the optimal fingerprint detection condition. Consequently, it is possible to reduce the total time required for the fingerprint detection including the time to search for the fingerprint detection condition, whereby high-speed sensing and low electric consumption become possible.
In addition, if in the first and second embodiments described above, the speed at which the scanning line driver 20 is driven in the preparation period to search for a fingerprint detection condition is the same as the speed at which a fingerprint information is read in an ordinary manner, then the time required for preparation becomes the same as the time required for reading the fingerprint in an ordinary manner. Consequently, it becomes impossible to make the time of the preparation period shorter than the time required in a conventional manner in which all the n×m capacitance detection circuits 31 arranged in the fingerprint detection part 30 are used in order to search for the fingerprint detection condition. On the contrary, according to the present embodiment, these problems do not occur, since the preparation period can be shorter than the conventionally required time by merely matching the driving speed of the data line driver 10 during the preparation period with the speed at which the fingerprint information is read in an ordinary manner.
More detailed description of this aspect is as follows. For example, suppose that 100×100 capacitance detection circuits 31 are arranged in the fingerprint detection part 30 (m=100, n=100). If the time required for reading information from one capacitance detection circuit 31 is 1 μs, the time to read one frame will be 100×100×1 μs=10 ms. Then, when reading the fingerprint information in an ordinary manner, the driving speed of the data line driver 10 is 500 kHz, while the driving speed of the scanning line driver is 1/m= 1/100 of 500 kHz; that is, 5 kHz. Therefore, if, in the preparation period, the driving speeds of the data line driver 10 and the scanning line driver 20 are the same as the speed at which a fingerprint information is commonly read, then, the time required for the preparation period in the third embodiment, in which the fingerprint detection condition is searched for by driving the data line driver 10, is 1/100 of what is required for the preparation period in the first or second embodiment in which the fingerprint detection condition is searched for by driving the scanning line driver 20. Thus, in the present embodiment, the requirement specification level can remain low, and cost reduction is possible since there is no need to improve the driving capacity of the scanning line driver 20 during the preparation period.
US11041265 2004-02-17 2005-01-25 Capacitance detection device, fingerprint sensor, biometric authentication device, and method for searching capacitance detection condition Active 2027-02-26 US7486809B2 (en)
JP2004040375A JP2005233688A (en) 2004-02-17 2004-02-17 Capacitance detection device, fingerprint sensor, biometrics authentication device, and search method for capacitance detection condition
JP2004-040375 2004-02-17
US20050179446A1 true US20050179446A1 (en) 2005-08-18
US7486809B2 true US7486809B2 (en) 2009-02-03
ID=34697993
US11041265 Active 2027-02-26 US7486809B2 (en) 2004-02-17 2005-01-25 Capacitance detection device, fingerprint sensor, biometric authentication device, and method for searching capacitance detection condition
US (1) US7486809B2 (en)
EP (1) EP1564674A1 (en)
JP (1) JP2005233688A (en)
KR (1) KR100704579B1 (en)
CN (1) CN100417913C (en)
CN100423019C (en) * 2005-08-05 2008-10-01 奇景光电股份有限公司;许孟烈 Fingerprint acquisition apparatus and method therefor
JP5489060B2 (en) * 2009-08-19 2014-05-14 Ｔｏｔｏ株式会社 Capacitive rotary device and capacitive depressed device
US20010026635A1 (en) 1998-09-08 2001-10-04 Stefan Jung Method and device for capacitive image acquisition
JP2001525067A (en) 1997-05-13 2001-12-04 ベリディコム，インコーポレイテッド Capacitive fingerprint sensor having an adjustable gain
JP2003254706A (en) 2002-03-04 2003-09-10 Seiko Epson Corp Electrostatic capacity detector
JP2003295982A (en) 2002-04-03 2003-10-17 Sharp Corp Input information processing device
JP2004089675A (en) 2002-07-12 2004-03-25 Seiko Epson Corp Personal identification unit, card type information recording medium, and information processing system using the same
US20050179446A1 (en) 2005-08-18 application
JP2005233688A (en) 2005-09-02 application
CN100417913C (en) 2008-09-10 grant
KR20050082151A (en) 2005-08-22 application
KR100704579B1 (en) 2007-04-06 grant
CN1657864A (en) 2005-08-24 application
EP1564674A1 (en) 2005-08-17 application
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HARA, HIROYUKI;MIYASAKA, MITSUTOSHI;REEL/FRAME:016224/0299