Fingerprint sensors using membrane switch arrays
First Claim
1. A method of making an integrated texture sensor for sensing a texture that is protected from external contaminating particulates and will self-equalize using air from outside the sensor, comprising:
- a) forming a plurality of row lines and a plurality of column lines on a substrate, each of the row lines and column lines being insulated from each other, the row lines and column lines intersecting to form a switch area between adjacent row lines and adjacent column lines;
b) forming a lower electrode in each of a plurality of switch areas;
c) forming a sacrificial area directly over each lower electrode and a non-sacrificial area around each sacrificial area;
d) forming a membrane above each sacrificial area, the membrane being anchored to the non-sacrificial area, the membrane comprising an upper electrode disposed directly above the sacrificial area, wherein the membrane does not cover a channel area adjacent to the sacrificial area;
e) removing each sacrificial area by introducing a sacrificial etchant through the channel area, thereby forming a cavity region at each sacrificial area; and
f) sealing the channel area so as to close each cavity region from the external contaminating particulates while still self-equalizing pressure using the air that is external to the sensor that can flow through the channel.
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Accused Products
Abstract
A method of making an integrated texture sensor for sensing a texture is described. In one embodiment, the method is directed to a sensor that that is protected from external contaminating particulates and will self-equalize using air from outside the sensor. Further combinations of such protection among various membrane switches, in combination with various types of membranes, is described. In another embodiment, a method of making a skin-texture sensor for sensing a skin texture having a plurality of ridges and a plurality of valleys is described, such that when completed, applying a ridge of the texture to a membrane switch will cause flexure of the membrane resulting in a contact between the lower electrode and the upper electrode, the contact establishing an electrical communication between said one of the row lines and said one of the column lines, whereas disposing a valley of the texture over said each membrane switch will not result in the contact between the lower electrode and the upper electrode.
63 Citations
19 Claims
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1. A method of making an integrated texture sensor for sensing a texture that is protected from external contaminating particulates and will self-equalize using air from outside the sensor, comprising:
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a) forming a plurality of row lines and a plurality of column lines on a substrate, each of the row lines and column lines being insulated from each other, the row lines and column lines intersecting to form a switch area between adjacent row lines and adjacent column lines;
b) forming a lower electrode in each of a plurality of switch areas;
c) forming a sacrificial area directly over each lower electrode and a non-sacrificial area around each sacrificial area;
d) forming a membrane above each sacrificial area, the membrane being anchored to the non-sacrificial area, the membrane comprising an upper electrode disposed directly above the sacrificial area, wherein the membrane does not cover a channel area adjacent to the sacrificial area;
e) removing each sacrificial area by introducing a sacrificial etchant through the channel area, thereby forming a cavity region at each sacrificial area; and
f) sealing the channel area so as to close each cavity region from the external contaminating particulates while still self-equalizing pressure using the air that is external to the sensor that can flow through the channel. - View Dependent Claims (2, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 19)
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7. A method of making a skin-texture sensor for sensing a skin texture having a plurality of ridges and a plurality of valleys, comprising:
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a) establishing a base;
b) disposing a plurality of conductive row lines on the base;
c) disposing a plurality of conductive column lines on the base, the column lines being insulated from the row lines; and
d) forming an array of membrane switches on the base such that a spacing between adjacent switches in the array is less than one half of a spacing between adjacent ridges, each membrane switch corresponding to a pair of one of the row lines and one of the column lines, wherein forming each membrane switch of the array comprises;
disposing a lower electrode on the base, electrically connecting the lower electrode to said one of the row lines, disposing a flexible upper membrane structure over the lower electrode, the membrane structure comprising an upper electrode disposed facing the lower electrode and connected to said one of the column lines, whereinapplying a ridge of the texture to said each membrane switch causes a flexure of the membrane resulting in a contact between the lower electrode and the upper electrode, the contact establishing an electrical communication between said one of the row lines and said one of the column lines, and wherein disposing a valley of the texture over said each membrane switch does not result in the contact between the lower electrode and the upper electrode. - View Dependent Claims (8, 9, 10, 11)
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Specification
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- Resources
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Current AssigneeLenovo PC International Limited (Lenovo Group Ltd.)
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Original AssigneeSpringworks, LLC (Petters Group Worldwide LLC)
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InventorsStoessel, Christian, Prakash, Shiva, Deconde, Keith T., Hovey, Steve H., Ganapathi, Srinivasan K., Gluck, Randolph S.
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Granted Patent
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Time in Patent OfficeDays
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Field of Search
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US Class Current29/593
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CPC Class CodesG06V 40/1306 non-optical, e.g. ultrasoni...G06V 40/1329 Protecting the fingerprint ...H01H 1/0036 Switches making use of micr...H01H 67/22 Switches without multi-posi...Y10T 29/49004 including measuring or test...
