Active Matrix Array Device
AssigneeKoninklijke Philips Electronics N.V.
InventorJohn R.A. Ayres
Life of this patent
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Abstract
An active matrix array device has driver circuitry for providing address signals to the matrix elements, including digital to analogue converter circuitry. This has a voltage selector for selecting a pair of voltages based on a first set of bits of the digital matrix element signal, and a converter arrangement for providing an analogue voltage level derived from the pair of voltages and from a second set of bits of the digital matrix element signal. The converter arrangement comprises first and second digital to analogue converter circuits (30, 32) in parallel and which are adapted to provide an analogue voltage level to an output of the converter arrangement alternately. The invention provides a more efficient use of substrate area for given circuit response requirements.
Claims27
An active matrix array device comprising an array of individually addressable matrix elements and driver circuitry for providing address signals to the matrix elements, the driver circuitry including digital to analogue converter circuitry for converting a digital pixel matrix element signal to an analogue drive level, wherein the digital to analogue converter circuitry comprises:
- a voltage selector (14) for selecting a pair of voltages based on a first set of bits (3 MSB) of the digital matrix element signal;
- and
- a converter arrangement (16) for providing an analogue voltage level derived from the pair of voltages and from a second set of bits (3 LSB) of the digital matrix element signal,
- wherein the converter arrangement comprises first and second digital to analogue converter circuits (30, 32) in parallel and which are adapted to provide an analogue voltage level to an output of the converter arrangement alternately.
An active matrix array device comprising an array of individually addressable matrix elements and driver circuitry for providing address signals to the matrix elements, the driver circuitry including digital to analogue converter circuitry for converting a digital pixel matrix element signal to an analogue drive level, wherein the digital to analogue converter circuitry comprises:
- a voltage selector (14) for selecting a pair of voltages based on a first set of bits (3 MSB) of the digital matrix element signal;
- and
- a converter arrangement (16) for providing an analogue voltage level derived from the pair of voltages and from a second set of bits (3 LSB) of the digital matrix element signal,
- wherein the converter arrangement comprises an amplifier (40) and a switched capacitor input arrangement (42) connected to the amplifier input, wherein the output of the amplifier (40) provides the output of the converter circuit, and wherein the input side of each capacitor (C′, C, 2C, 4C) of the capacitor arrangement (42) is coupled to the output of the amplifier through a respective feedback switch (46).
20-21. (canceled)
Digital to analogue converter circuitry for converting a digital signal to an analogue drive level, comprising:
- a voltage selector (14) for selecting a pair of voltages based on a first set of bits (3 MSB) of the digital signal;
- and
- a converter arrangement (16) for providing an analogue voltage level derived from the pair of voltages and from a second set of bits of the digital signal,
- wherein the converter arrangement comprises first and second digital to analogue converter circuits (30,32) in parallel and which are adapted to provide an analogue voltage level to an output of the converter arrangement alternately.
Digital to analogue converter circuitry for converting a digital signal to an analogue drive level, comprising:
- a voltage selector (14) for selecting a pair of voltages based on a first set of bits (3 MSB) of the digital signal;
- and
- a converter arrangement (16) for providing an analogue voltage level derived from the pair of voltages and from a second set of bits (3 LSB) of the digital signal,
- wherein the converter arrangement comprises an amplifier (40) and a switched capacitor input arrangement (42) connected to the amplifier input, wherein the output of the amplifier (40) provides the output of the converter circuit, and wherein the input side of each capacitor (C′, C, 2C, 4C) of the capacitor arrangement (42) is coupled to the output of the amplifier through a respective feedback switch (46).
A method of providing address signals to the matrix elements of an active matrix array device comprising an array of individually addressable matrix elements, the method comprising:
- selecting a pair of voltages (VH, VL) based on a first set of bits (3 MSB) of a digital matrix element signal;
- and
- providing an analogue voltage level derived from the pair of voltages and from a second set of bits (3 LSB) of the digital matrix element signal,
- wherein the analogue voltage level is provided alternately by first and second digital to analogue converter circuits (30,32) in parallel.
28-31. (canceled)
Dependencies are inferred from the claim text.