发明授权
US07522753B2 Electrostatic discharge protection of a capacitive type fingerprint sensing array 失效
电容型指纹感测阵列的静电放电保护

  • 专利标题: Electrostatic discharge protection of a capacitive type fingerprint sensing array
  • 专利标题(中): 电容型指纹感测阵列的静电放电保护
  • 申请号: US11162861
    申请日: 2005-09-27
  • 公开(公告)号: US07522753B2
    公开(公告)日: 2009-04-21
  • 发明人: Alexander KalnitskyAlan Kramer
  • 申请人: Alexander KalnitskyAlan Kramer
  • 申请人地址: US CA Emeryville
  • 专利权人: UPEK, Inc.
  • 当前专利权人: UPEK, Inc.
  • 当前专利权人地址: US CA Emeryville
  • 代理商 Jonathan A. Small
  • 主分类号: G06K9/00
  • IPC分类号: G06K9/00
Electrostatic discharge protection of a capacitive type fingerprint sensing array
摘要:
A planar fingerprint pattern detecting array includes a large number of individual skin-distance sensing cells that are arranged in a row/column configuration. Each sensing cell includes an amplifier having an ungrounded input mode and an ungrounded output node. Output-to-input negative feedback that is sensitive to the fingerprint pattern is provided for each amplifier by way of (1) a first capacitor plate that is placed vertically under the upper surface of a dielectric layer and is connected to the ungrounded amplifier input node, (2) a second capacitor plate that is placed vertically under the upper surface of the dielectric layer in close horizontal spatial relation to the first capacitor plate and is connected to the ungrounded output node, and (3) an ungrounded fingertip whose fingerprint pattern is to be detected, which ungrounded fingertip is placed on the upper surface of the dielectric layer in close vertical spatial relation with the first and second capacitor plates. Electrostatic discharge protection relative to electrostatic potential that may be carried by the ungrounded fingertip is provided by placing a number of grounded metal paths within the dielectric layer to spatially surround each of the first and second capacitor plates, this being done in a manner that does not disturb the ungrounded state of the fingertip.
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