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US 6,667,740 B2Granted
Position sensor
AssigneeSynaptics (UK) Limited
InventorsDavid T. Ely, Ian P. Collins, Peter D. Cauwood, Steven R. Brace
Life of this patent
Estimating the term…
Abstract
A low cost x-y digitising system is provided for use in consumer electronic devices, such as portable digital assistants, mobile telephones, web browsers and the like. The digitiser includes a resonant stylus, an excitation winding for energising the resonant stylus and a set of sensor windings for sensing the signal generated by the stylus, from which the x-y position of the stylus is determined.
Claims37
A stylus for use with a position detector, the stylus comprising:
- an elongate housing;
- a movable tip mounted at one end of the housing for axial movement relative thereto in a first direction from a retracted position to an extended position and in a second, opposite direction from the extended position to the retracted position;
- a sensing coil fixed in the housing and having an abutment surface facing in said second direction;
- a flux linkage element mounted to the tip for movement relative to the coil;
- and
- movement-limiting means to define the extent of movement of the tip relative to the housing between said extended and retracted positions, said movement-limiting means comprising:
- a first limiting element mounted to the flux linkage element and having a first abutment surface facing in said first direction and a second abutment surface facing in said second direction;
- a second limiting element fixed in the housing axially adjacent to the coil and having first and second abutment surfaces facing in said first direction, the first abutment surface contacting the abutment surface of the coil;
- and
- the arrangement being such that when the tip is in the retracted position, the second abutment surface of the first limiting element contacts the second abutment surface of the second limiting element and when the tip is in the extended position the second abutment surface of the first limiting element contacts the abutment surface of the coil.
7 more elements
A stylus for use with a position detector, the stylus comprising:
- an elongate housing;
- a movable tip mounted at one end of the housing for axial movement relative thereto in a first direction from a retracted position to an extended position and in a second, opposite direction from the extended position to the retracted position;
- a sensing coil fixed in the housing and having an abutment surface facing in said second direction;
- a flux linkage element mounted to the tip for movement relative to the coil;
- and
- movement-limiting means to define the extent of movement of the tip relative to the housing between said extended and retracted positions, said movement-limiting means comprising a limiting element mounted to the flux linkage element and having an abutment surface facing in said first direction for contacting the abutment surface of said coil when the tip is in said extended position;
- characterised in that said flux linkage element is elongate and wherein the limiting element comprises a blind bore of a predetermined depth for receiving and holding said elongate element, whereby when the tip is in said extended position, the end of said elongate element is a predetermined distance from the abutment surface of said coil.
4 more elements
A stylus for use with a position detector, the stylus comprising:
- an elongate housing;
- a movable tip mounted at one end of the housing for axial movement between a retracted position and an extended position;
- a formerless sensing coil;
- and
- a flux linkage element which extends through the coil;
- wherein said formerless coil and said flux linkage element are mounted for relative movement with the movement of said tip, whereby the inductance of said coil is changed with the movement of said tip.
3 more elements
A stylus as for use with a position detector, the stylus comprising:
- an elongate housing;
- a movable tip mounted at one end of the housing for axial movement relative thereto in a first direction from a retracted position to an extended position and in a second, opposite direction from the extended position to the retracted position;
- a sensing coil;
- a flux linkage element;
- wherein the sensing coil and the flux linkage element are mounted for relative movement with the movement of said tip, whereby the inductance of said coil is changed with the movement of said tip;
- characterised by a movement limiter which defines the extent of movement of the tip relative to the housing between said extended and retracted positions, said movement limiter comprising a first limiting element mounted for movement with the tip and a second movement-limiting element fixed in the housing;
- wherein said first and second limiting elements comprise a first abutment surface facing in said first direction and a second abutment surface facing in said second direction and wherein the arrangement is such that when the tip is in the retracted position the second abutment surface of the first limiting element contacts the first abutment surface of the second limiting element and when the tip is in the extended position the first abutment surface of said first limiting element contacts the second abutment surface of said second limiting element.
4 more elements
A stylus for use with a position detector, the stylus comprising:
- an elongate housing;
- a movable tip mounted at one end of the housing for axial movement relative thereto in a first direction from a retracted position to an extended position and in a second, opposite direction from the extended position to the retracted position;
- a sensing coil having an abutment surface;
- a flux linkage element;
- wherein said sensing coil and said flux linkage element are mounted for relative movement with the movement of said tip, whereby the inductance of the coil is changed with the movement of the tip;
- and
- movement limiter operable to limit the movement of the tip relative to the housing comprising a limiting element mounted for movement with the tip and having an abutment surface facing in said first direction for contacting the abutment surface of said coil when the tip is in said extended position;
- characterised in that said flux linkage element is elongate and wherein the limiting element comprises a blind bore of a predetermined depth within said abutment surface for receiving and holding said elongate element, whereby when the tip is in said extended position, the end of said elongate element is a predetermined distance from the abutment surface of said coil.
5 more elements
Dependencies are inferred from the claim text.