US6404136B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and circuit for controlling an emission current
Assignee: Motorola Solutions Inc
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Filing: 2000-07-05
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Granted: 2002-06-11
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Expires: 2020-07-05
Abstract
Abstract A method for controlling an emission current ( 134 ) in a field emission display ( 100 ) includes measuring an emission current ( 134 ), measuring a portion of the plurality of pixels receiving emission current ( 134 ) as a percentage of the plurality of pixels on the anode ( 138 ) to define a set point, comparing measured value to set point value and adjusting gate voltage to cause emission current to approach set point value. A field emission display ( 100 ) includes a control circuit ( 111 ), which has an analog-to-digital converter ( 150 ), a current controller ( 154 ), as display timing controller ( 151 ) and a gate voltage source ( 158 ). Analog-to-digital converter ( 150 ) is designed to be connected to power supply ( 146 ). Gate voltage source ( 158 ) is connected to gate extraction electrode ( 126 ) and applies thereto the offset voltage, which is manipulated by current controller ( 154 ) in response to an output signal ( 152 ) of analog-to-digital converter ( 150 ) and an output signal of display timing controller ( 151 ).
Inventors
- 👤 David Murray
- 👤 Ken Foo
- 👤 Kim A. Hasler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:28
CPC Classifications
G; G09; G09G; G09G3/00; G09G3/20; G09G3/22; G09G2320/00; G09G2320/04; G09G2320/043; G09G2320/06; G09G2320/0626
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
144 words
A method for controlling an emission current in a field emission display comprising the steps of: providing a plurality of electron emitter structures designed to emit electrons which define the emission current; providing a gate extraction electrode; applying a gate voltage to the gate extraction electrode; providing an anode having a plurality of pixels, wherein the plurality of pixels are designed to receive the emission current, and wherein at least a portion of the plurality of pixels receives the emission current; measuring the emission current, which defines a measured value; measuring the portion of the plurality of pixels receiving the emission current as a percentage of the plurality of pixels on the anode to define a set point value; comparing the measured value with the set point value, and adjusting the gate voltage to cause the emission current to approach the set point value.
Claim 2
Independent Claim
144 words
A method for controlling an emission current in a field emission display comprising the steps of: providing a plurality of electron emitter structures designed to emit electrons which define the emission current; providing a gate extraction electrode; applying a gate voltage to the gate extraction electrode; providing an anode having a plurality of pixels, wherein the plurality of pixels are designed to receive the emission current, and wherein at least a portion of the plurality of pixels receives the emission current; measuring the emission current, which defines a measured value; measuring the portion of the plurality of pixels receiving the emission current as a percentage of the plurality of pixels on the anode to define a set point value; comparing the measured value with the set point value, and adjusting the gate voltage to cause the emission current to approach the set point value.
Claim 3
Dependent Claim
43 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , further comprising the step of receiving a video signal having pixel data indicating the portion of the plurality of pixels to receive the emission current.
Claim 4
Dependent Claim
36 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , wherein the step of adjusting the gate voltage is performed continuously during operation of the field emission display.
Claim 5
Dependent Claim
47 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , wherein the step of measuring the emission current comprises the steps of receiving the emission current at the anode which defines an anode current, and measuring the anode current.
Claim 6
Dependent Claim
59 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , further comprising the step of coupling the anode to a power supply, and wherein the step of measuring the emission current comprises the steps of receiving the emission current at the anode and measuring a power output of the power supply.
Claim 7
Dependent Claim
59 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , further comprising the step of coupling the anode to a power supply, and wherein the step of measuring the emission current comprises the steps of receiving the emission current at the anode and measuring a current passing through the power supply.
Claim 8
Dependent Claim
49 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , wherein the step of adjusting the gate voltage comprises the step of adjusting the gate voltage in a manner sufficient to cause the emission current to equal the set point value.
Claim 9
Dependent Claim
71 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , wherein the step of applying a gate voltage comprises the step of applying an offset voltage to the gate extraction electrode, and wherein the step of adjusting the gate voltage comprises the step of adjusting the offset voltage in a manner sufficient to cause the emission current to approach the set point value.
Claim 10
Dependent Claim
48 words
The method for controlling an emission current in a field emission display as claimed in claim 1 , wherein the step of measuring the portion of the plurality of pixels receiving the emission current comprises the step of defining the set point based on a maximum anode current.
Claim 11
Dependent Claim
127 words
A field emission display comprising: a plurality of electron emitter structures designed to emit electrons which define an emission current; a gate extraction electrode spaced apart from the plurality of electron emitters; an anode having a plurality of pixels, wherein the plurality of pixels are disposed to receive emission current, and wherein at least a portion of the plurality of pixels receives the emission current; and a control circuit coupled to the anode and the gate extraction electrode, wherein the control circuit is coupled for receiving a video signal having pixel data which defines the portion of the plurality of pixels to receive emission current, and wherein the control circuit adjusts the emission current based on the portion of the plurality of pixels to receive emission current.
Claim 12
Dependent Claim
127 words
A field emission display comprising: a plurality of electron emitter structures designed to emit electrons which define an emission current; a gate extraction electrode spaced apart from the plurality of electron emitters; an anode having a plurality of pixels, wherein the plurality of pixels are disposed to receive emission current, and wherein at least a portion of the plurality of pixels receives the emission current; and a control circuit coupled to the anode and the gate extraction electrode, wherein the control circuit is coupled for receiving a video signal having pixel data which defines the portion of the plurality of pixels to receive emission current, and wherein the control circuit adjusts the emission current based on the portion of the plurality of pixels to receive emission current.
Claim 13
Dependent Claim
24 words
The field emission display as claimed in claim 10 , wherein the emission current is adjusted continuously during operation of the field emission display.
Claim 14
Dependent Claim
40 words
The field emission display as claimed in claim 10 , wherein the emission current is adjusted based on a portion of the plurality of pixels receiving the emission current as a percentage of the plurality of pixels on the anode.
Claim 15
Dependent Claim
151 words
The field emission display as claimed in claim 10 , wherein the control circuit comprises: a power supply having a first and second output, wherein the first output is coupled to the anode; an analog-to-digital converter having an input and an output, wherein the input is coupled to the second output of the power supply; a current controller having a first input, a second input and an output, wherein the second input is coupled to the output of the analog-to-digital converter; a display timing controller having an input and an output, wherein the input is coupled for receiving the video signal having pixel data, and wherein the output is coupled to the first input of the current controller; and a gate voltage source having an input and an output, wherein the input is coupled to the output of the current controller and the output is coupled to the gate extraction electrode.
Claim 16
Dependent Claim
60 words
The field emission display as claimed in claim 13 , wherein the gate voltage source comprises an offset voltage source and a scanning voltage source, wherein the offset voltage source is operably coupled to the scanning voltage source, such that the scanning voltage source, when activated, adds a scanning voltage to an offset voltage provided by the offset voltage source.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2005-06-10 | 2005-12-10 | 2006-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-06-10 | 2009-12-10 | 2010-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2013-06-10 | 2013-12-10 | 2014-06-11 | $7700.00 | Window Closed / Lapsed |