公开(公告)号：EP1005689A4

公开(公告)日：2001-01-17

申请号：EP98924960

申请日：1998-05-28

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L

IPC: G09G3/30 ,  G09G3/20 ,  G09G3/22 ,  G09G3/36

CPC classification number: G09G3/22 ,  G09G3/2007 ,  G09G3/2011 ,  G09G3/2014 ,  G09G2310/0267 ,  G09G2320/043 ,  G09G2320/0606 ,  G09G2320/0626

Abstract: A circuit (300) and method for controlling the brightness of a display screen (200) implemented using a flat panel field emission display (FED) screen (200). A brightness control circuitry (300) is positioned across the row drivers (220) for altering the applied voltage (212) to the rows (230) causing a change in brightness cross the FED screen (200). The applied voltage (212) can be pulse width modulated or amplitude modulated to alter the brightness of the FED screen (200). Within one FED screen (200) implementation, it is more efficient to alter the row voltage (212); however, in alternative embodiment of the present invention the column voltages (207) are modulated in amplitude or pulse width to alter the brightness of the FED screen (200). The brightness control circuitry (300) of the present invention can be made responsive to a manual brightness knob (520) or can be responsive to an ambient light sensor (580a, 580b).

公开(公告)号：EP1031129A4

公开(公告)日：2001-01-10

申请号：EP98937003

申请日：1998-07-23

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L ,  SPINDT CHRISTOPHER J

IPC: G09G3/20 ,  G09G3/22 ,  G09G3/00 ,  G09G3/10

CPC classification number: G09G3/22 ,  G09G2320/029 ,  G09G2320/041 ,  G09G2320/043 ,  G09G2320/0606 ,  G09G2320/0626

Abstract: A method and apparatus to provide performance adjustments for FEDs during operation are provided. More specifically, the present invention provides two circuit embodiments for compensating for temperature induced brightness variations of the panel display. In a closed loop embodiment, a sample display circuit (501) that is substantially similar to a FED (300) being adjusted is used to generate a performance indicator signal which is compared against a reference signal to determine a difference signal. The difference signal is then used to adjust the operation performance of the FED as well as the sample display circuit. In an opened loop embodiment, a current source (609) generates a reference current across a sample resistor (603) which is made from the same material as the resistor layer (111) inside the FED's cathode (107). The voltage across the sample resistor is compared against a reference signal to determine a difference signal. The difference signal is then used to increase or decrease the brightness of the panel display, as needed, to compensate for temperature induced variations or other types of environment induced variations (e.g., humidity, aging, mild voltage drift that creates undesirable current drift, etc.) thereof.

公开(公告)号：EP1114411A4

公开(公告)日：2004-06-02

申请号：EP99935552

申请日：1999-07-14

Applicant: CANDESCENT TECH CORP

Inventor： MASLENNIKOV IGOR L ,  URBON DENNIS M ,  SPINDT CHRISTOPHER J ,  HANSEN RONALD L ,  CURTIN CHRISTOPHER J

IPC: H01J29/04 ,  G09G3/20 ,  G09G3/22 ,  H01J31/12 ,  H04N5/68 ,  G09G3/12

CPC classification number: G09G3/22 ,  G09G3/2011 ,  G09G2310/0267 ,  G09G2310/06 ,  G09G2320/029 ,  G09G2320/043 ,  G09G2330/02 ,  G09G2330/028

Abstract: A field emission display (700) having an improved operational life. In one embodiment, the field emission display (700) comprises a plurality of row lines (230), a plurality of column lines (250), and a plurality of electron emissive elements (40) disposed at intersections of the plurality of row lines (230) and column lines (250), a column driver circuit (740) and a row driver circuit (720). The column driver circuit (740) is coupled to drive column voltage signals over the plurality of column lines (250); and the row driver circuit (720) is coupled to activate and deactivate the plurality of row lines (230) with row voltage signals. According to the present invention, operation life of the field emission display is extended when the electron emissive elements are intermittently reverse-biased by the column voltage signals and the row voltage signals. In another embodiment, the row driver circuit is responsive to a SLEEP signal (770). The row driver circuit (720), upon receiving the SLEEP signal (770), drives a sleep-mode voltage over the row lines (230) to reverse-bias the electron emissive elements.

公开(公告)号：EP1066618A4

公开(公告)日：2001-11-07

申请号：EP98960800

申请日：1998-12-07

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L ,  FRIEDMAN JAY ,  STOIAN LEE

IPC: G09G3/20 ,  G09G3/22 ,  G09G3/32

CPC classification number: G09G3/22 ,  G09G3/2011 ,  G09G2310/027 ,  G09G2320/043 ,  G09G2320/0606 ,  G09G2320/0626 ,  G09G2320/0666

Abstract: A circuit for time multiplexing a voltage signal for controlling the color balance of a flat panel display (200). Within an FED screen, a matrix of rows (230) and columns (250) is provided and emitters are situated within each row-column intersection (100). Rows are sequentially activated during 'row on-time windows' by row drivers (220) and corresponding individual gray scale information (voltages) are driven over the columns by column drivers (240). Within each column driver, the present invention provides selection circuitry for driving a first voltage signal during a first part of the row on-time window and a second voltage during a second part of the row on-time window. The lengths of the first part and second part of the row on-time window can be adjusted for a given color, to adjust the color balance with respect to color.

公开(公告)号：EP1016061A4

公开(公告)日：2001-01-17

申请号：EP98918827

申请日：1998-04-27

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L

IPC: G09G3/20 ,  G09G3/22 ,  G09G5/10

CPC classification number: G09G3/22 ,  G09G5/10 ,  G09G2320/029 ,  G09G2320/043 ,  G09G2320/0626 ,  G09G2360/144 ,  G09G2360/145

Abstract: A circuit and method for controlling the brightness of a display screen implemented using a field emission display (FED) screen (200). In an automatic brightness adjustment embodiment, an ambient light sensor (580) supplies the brightness signal that changes in proportion to the light sensed. The FED screen brightness is increased in response to increases in the light sensor output and decreased in response to decreases in the light sensor output. Another embodiment uses the light sensor (580) for brightness normalization where the FED screen (200) is used as the reference light level and the FED screen brightness is compensated for due to variations caused by age and manufacturing differences. A manual brightness adjustment (override) and automatic brightness on/off switch are also provided.

公开(公告)号：EP0965248A4

公开(公告)日：2000-05-31

申请号：EP97910729

申请日：1997-10-17

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L ,  SPINDT CHRISTOPHER J ,  FIELD JOHN E

IPC: H01J1/304 ,  G09G3/20 ,  G09G3/22 ,  H05B37/00

CPC classification number: G09G3/22 ,  G09G2310/027 ,  G09G2320/0276 ,  H01J2329/00

Abstract: A voltage-adjustment section (20) of an electronic device converts an input control voltage (VI) into an output control voltage (VO) in such a way that a collector current (ICP) form with electrons emitted from an emitter (EP) of an emission/collection cell (26), or triode, varies in a desired, typically linear, manner with the input control voltage. The triode further includes a collector (CP) that carries the collector current and a gate electrode (GP) that regulates the collector current as a function of the output control voltage. Control of the collector current so as to achieve the desired current/voltage relationship is achieved with an analog control loop containing the triode and an amplifier (28) coupled between the triode's collector and gate electrode. The triode thus typically has a linear gamma characteristic relative to the input control voltage. The voltage-adjustment section is suitable for use in a display device such as a flat-panel display.

公开(公告)号：EP1364361A4

公开(公告)日：2005-07-06

申请号：EP02725025

申请日：2002-02-26

Applicant: CANDESCENT TECH CORP

Inventor： DUNPHY JAMES C ,  HANSEN RONALD L ,  LINDBERG BRIAN E ,  TRUPPA JEROME M ,  ELLOWAY DONALD J ,  AMANIAMPONG DUKE K

IPC: H01J29/04 ,  G09G3/20 ,  G09G3/22 ,  H01J9/44 ,  H01J29/28 ,  H01J29/62 ,  H01J29/94 ,  H01J29/96 ,  H01J31/12

CPC classification number: H01J9/44 ,  G09G3/22 ,  G09G2310/066 ,  H01J2209/0223

Abstract: A circuit and method for turning-on and turning-off elements of an field emission display device to protect against emitter electrode(60) and gate electrode(50) degradation. The circuit(910) includes control logic(916) having a sequencer which in one embodiment can be realized using a state machine. Upon power-on, the control logic sends an enable signal to a high voltage power supply (912) that supplies voltage to the anode electrode (914). At this time a low voltage power supply (918) and driving circuitry (920)are disabled. Upon receiving a confirmation signal from the high voltage power supply, the control logic enables the low voltage power supply which supplies voltage to the driving circuitry (920). Upon receiving a confirmation signal from the low voltage power supply (918), or optionally after expiration of a predetermined time period, the control logic (916) then enables the driving circuitry (920) which drives the gate electrodes (50) and the emitter electrodes (60) which make up the rows and columns of the FED device. Upon power down, the control logic (916) first disables the low voltage power supply (918), then the high voltage power supply (912).

公开(公告)号：EP1074015A4

公开(公告)日：2001-11-07

申请号：EP98961963

申请日：1998-12-07

Applicant: CANDESCENT TECH CORP

Inventor： HANSEN RONALD L ,  FRIEDMAN JAY ,  FREIBERG PAUL

IPC: G09G3/20 ,  G09G3/22 ,  G09G3/32

CPC classification number: G09G3/22 ,  G09G3/2011 ,  G09G2310/027 ,  G09G2320/043 ,  G09G2320/0606 ,  G09G2320/0626 ,  G09G2320/0666

Abstract: A circuit and method for time multiplexing a voltage signal for controlling the color balance of a flat panel display, Field Emission Display (200). Row drivers (220) are sequentially activated during 'row on-time windows' and corresponding individual gray scale information (voltage) are driven by column drivers (240). In one embodiment, within each column driver (240a(i)), a first error compensation circuit (810a(i)), during the first frame of each frame pair, divides the first voltage data and generates a second voltage data having a negative error, and a second error compensation circuit (820a(i)) during the second frame of each frame pair generates a second voltage data having a positive error. Selection circuitry for driving a first voltage data during a first part of the row on-time window and a second voltage data during a second part of the row on-time window comprises multiplexers (830a(i) and 834a(i)), output register (320(i)), decoder (330a(i)), digital-to-analog converter (340a(i)), channel amplifier (370a(i)).

Abstract translation: 一种用于时间多路复用电压信号以控制平板显示器的色彩平衡的电路和方法，场发射显示器（200）。 行驱动器（220）在“行开启时间窗”期间被顺序地激活，并且对应的单独灰度级信息（电压）由列驱动器（240）驱动。 在一个实施例中，在每个帧对的第一帧期间，第一误差补偿电路（810a（i））在每个列驱动器（240a（i））内分割第一电压数据并且生成具有负的第二电压数据 误差，并且在每个帧对的第二帧期间第二误差补偿电路（820a（i））产生具有正误差的第二电压数据。 用于在行导通时间窗的第一部分期间驱动第一电压数据的选择电路和在行导通时间窗的第二部分期间的第二电压数据包括多路复用器（830a（i）和834a（i）），输出 （320a（i）），解码器（330a（i）），数模转换器（340a（i）），信道放大器（370a（i））。