US007907137B2
`
`(12) United States Patent
`Shirasaki et al.
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 7,907,137 B2
`Mar. 15, 2011
`
`(54) DISPLAY DRIVE APPARATUS, DISPLAY
`APPARATUS AND DRIVE CONTROL
`METHOD THEREOF
`
`(75) Inventors: Tomoyuki Shirasaki, Higashiyamato
`(JP); Jun Ogura, Fussa (JP)
`(73) Assignee: Casio Computer Co., Ltd., Tokyo (JP)
`
`2/2005 Takahara et al.
`2005/0041002 A1
`3/2005 Yamano et al.
`2005/0057580 A1
`6/2007 Tsuge et al.
`2007, 0146251 A1
`2/2008 Shirasaki et al.
`2008.0030495 A1
`8, 2008 Nathan et al.
`2008/O191976 A1
`2008/0225.027 A1* 9/2008 Toyomura et al. ............ 345.204
`2008/0238953 A1 10/2008 Ogura
`2009/0189924 A1* 7/2009 Ogura ........................... 345,690
`(Continued)
`
`(*) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1285 days.
`(21) Appl. No.: 11/391,941
`
`CN
`
`FOREIGN PATENT DOCUMENTS
`1552052 A 12, 2004
`(Continued)
`
`OTHER PUBLICATIONS
`
`(22) Filed:
`
`Mar. 29, 2006
`
`(65)
`
`(30)
`
`Prior Publication Data
`US 2006/0221 O15A1
`Oct. 5, 2006
`
`Foreign Application Priority Data
`
`Mar. 31, 2005 (JP) ................................. 2005-101.905
`Mar. 31, 2005 (JP) ................................. 2005-105373
`
`(51) Int. Cl.
`(2006.01)
`G09G 5/00
`(52) U.S. Cl. ............. 34.5/212:345/98:345/99; 34.5/100;
`34.5/204
`(58) Field of Classification Search .............. 345/76–83,
`345/87-100, 204 215,690
`See application file for complete search history.
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`7.358,941 B2 * 4/2008 Ono et al. ....................... 345/82
`7,561,147 B2
`7/2009 Tsuge
`7,583,261 B2 * 9/2009 Shirasaki et al. ............. 345,212
`7,719,492 B2
`5, 2010 Childs
`2004/0239596 A1 12, 2004 Ono et al.
`2004/0246212 A1 12/2004 Kobayashi et al.
`2005, OO3O264 A1
`2/2005 Tsuge et al.
`
`Chinese Office Action (and English translation thereof) dated Nov.
`27, 2008, issued in a counterpart Chinese Applications.
`(Continued)
`Primary Examiner — Vijay Shankar
`(74) Attorney, Agent, or Firm — Holtz, Holtz, Goodman &
`Chick, PC
`
`ABSTRACT
`(57)
`There is provided a display drive apparatus for operating, in
`accordance with display data, a current control type optical
`elements each having a display pixel provided with the opti
`cal element and a drive element which Supplies a driving
`current to the optical element. The display drive apparatus
`includes a gradation signal creating circuit which generates a
`gradation signal corresponding to a luminance gradation of
`the display data and Supplies the gradation signal to the dis
`play pixel, a threshold Voltage detection circuit which detects
`a threshold voltage peculiar to the drive element of the display
`pixel, and a compensation Voltage application circuit which
`generates a compensation Voltage for compensating for the
`threshold voltage of the drive element on the basis of the
`threshold Voltage and applies the compensation Voltage to the
`drive element.
`
`39 Claims, 36 Drawing Sheets
`
`ThSHD
`coPENSATON
`AA
`
`FRAMEMEMORY
`
`--170
`
`EE
`AA
`
`--.
`
`rerun-
`SHIFTRESTER
`SPLAY
`ATAREGISTRUMIT
`AA
`THREshould
`THRESH
`DisPLAY
`consiTION
`DETECTONAA
`DATA
`DATA
`ISPLAYAAATCH
`50--WhdATALATchMT
`UNIT
`-12
`49 -- With Axe With Act -1509-30
`EMERATIONNIT
`PRECARE
`TECTION
`RABATONSNAL
`WOLTASE
`WLF AE
`(SRAEAONCURRENT
`NoN-LIHTERTIN
`detecTING
`DISPLAYWOTAGE
`WOAGE
`
`13
`
`- :
`
`Cs
`
`m
`4
`
`.
`
`It
`
`weomagniD)
`
`180-
`se SNAA
`
`| 161
`
`------ st-wa-
`
`o
`
`WL
`
`e tas
`J
`real
`}
`- H -- 4-ve
`3.
`? i-f
`s
`|-
`N
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 001
`
`

`

`US 7,907,137 B2
`Page 2
`
`U.S. PATENT DOCUMENTS
`2009,0201231 A1
`8/2009 Takahara et al.
`2009/02O7160 A1*
`8, 2009 Shirasaki et al. .
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`.
`
`. 345,212
`
`FOREIGN PATENT DOCUMENTS
`6, 2004
`1434 193
`A1
`12/1996
`8-330600
`5, 2001
`2001-147659
`T 2003
`2003-1958.10
`1, 2004
`2004-004675
`1, 2004
`2004-021219
`9, 2004
`2004-252110
`4/2005
`2005-115144
`5, 2006
`2006-11918O
`T 2006
`2006-178028
`T 2006
`2006-195477
`7/2007
`2007-519956
`2, 2008
`2008-504576
`10, 2003
`2003-0078741
`5, 2004
`10-2004-0041620
`4/2006
`10-2006-0032530
`
`A
`
`EP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`JP
`KR
`KR
`KR
`
`OTHER PUBLICATIONS
`International Preliminary Report on Patentability and Written Opin
`ion dated Aug. 29, 2006, issued in International Application No.
`PCT/JP2006/307283 filed Mar. 30, 2006, 12 sheets.
`Korean Office Action dated Aug. 31, 2009 and English translation
`thereof issued in a counterpart Korean Application No. 10-2007
`0077017 of related U.S. Appl. No. 1 1/888.474.
`Japanese Office Action dated Jun. 13, 2008 and English translation
`thereof issued in a counterpart Japanese Application No. 2006
`209534 of related U.S. Appl. No. 1 1/888,474.
`Japanese Office Action dated Jun. 11, 2008 and English translation
`thereof issued in a counterpart Japanese Application No. 2006
`218805 of related U.S. Appl. No. 1 1/888,474.
`Japanese Office Action dated Apr. 22, 2010 and English translation
`thereof in counterpart Japanese Application No. 2005-10 1905.
`Japanese Office Action dated Apr. 22, 2010 and English translation
`thereof in counterpart Japanese Application No. 2005-105373.
`* cited by examiner
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 002
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 1 of 36
`
`US 7,907,137 B2
`
`cAESN
`DATA
`DISPLAY
`DATA
`
`
`
`FRAME MEMORY
`
`170
`
`
`
`THRESHOLD
`DESION
`
`110
`
`SHIFT REGISTER
`DATA REGISTER UNIT
`DISPLAY
`THRESHOLD
`THRESHOLD
`DATA
`coMSNATION
`DETECTION DATA
`160 u-Vth DATA LATCHUNIT
`DISPLAYRAA LATCH-120
`GRADATION SIGNAL
`140
`Vth ADC Vth DAC -150 GENERATION UNIT
`130
`DETECTION
`PRE-CHARGE
`GRADATIONSIGNAL
`VOLTAGE
`VOLAGE/
`(GRADATION CURRENT/
`DETECTING
`NON-LIGHT EMITTING
`WOLTAGE
`DISPLAY VOLTAGE)
`9 Ao
`
`180-
`
`SWITCHING
`CONTROL
`SIGNAL AZ
`
`
`
`100
`
`VcomigND)
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 003
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 2 of 36
`
`US 7,907,137 B2
`
`THRESHOLD VOLTAGE
`DETECTION PERIODTdec
`-Ho
`VOLTAGE.--VOLTAGE.-- VOLTAGE
`APPLICATION CONVERGENCE READING
`PERIODTpv :
`PERIODTcv
`PERIOD Trv
`
`SWITCHING CONTROL
`SIGNAL AZ
`
`
`
`Vth DAC OUTPUT
`
`SELECTION SIGNALSse
`
`POWER SUPPLY
`VOLTAGE VSC
`
`ve-rich
`t
`Vs (GND) -----H
`VOLTAGEWgs. BETWEENGATE Vcp.....
`AND SOURCE OF THIN FILM
`TRANSISTOR Tr13
`(BOTH-ENDS POTENTIAL
`Vc OF CAPACITOR Cs)
`
`
`
`O--------------------------------
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 004
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 3 of 36
`
`US 7,907,137 B2
`
`-
`
`FRAME MEMORY
`
`...
`DISPLAY................
`(PSE
`
`SHIFT REGISTERI
`nAARESISTERNIT
`DATA REGISTER UNIT
`
`170
`---
`
`""
`110
`
`DISPLAYEAA LATCH
`With DATA LATCH UNIT
`with ADc Vth DAC -150 GADA9SIGNA
`GENERATION UNIT
`DETECTING
`VOLTAGE Vpw
`
`
`
`O
`
`O
`
`160
`
`140
`
`180 -
`
`
`
`SWITCHING
`CONTROL -
`SIGNALAZ (H)
`
`
`
`
`
`
`
`O
`Vcom (GND)
`
`-1
`PX
`
`FIG.3
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 005
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 4 of 36
`
`US 7,907,137 B2
`
`-----
`
`FRAME MEMORY
`
`------
`DISPLAY------------
`(PSE
`
`SHIFT REGISTER/
`ATARFOSSTERNIT
`DATA REGISTER UNIT
`
`170
`---
`
`110
`
`
`
`With DATA LATCH UNIT
`
`
`
`
`
`
`
`150ASSIGNA-130
`
`
`
`- - - 182
`
`Y
`
`OO
`
`up
`
`L
`Evcom)
`
`140
`
`180-
`
`SS
`SIGNALAZ (L)
`
`
`
`-
`1.
`181
`
`SSel
`(H)
`
`
`
`na
`
`VcomigND)
`
`to
`
`
`
`-1
`PX
`
`FIG.4
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 006
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 5 of 36
`
`US 7,907,137 B2
`
`---
`
`FRAME MEMORY
`
`ti------
`DISPLAY.................
`(PSE
`
`SHIFT REGISTER
`DATA REGISTER UNIT
`A REGISTERU
`
`170
`
`THRESHOLD
`DETECTION
`DATA
`
`O
`
`
`
`O
`
`N-1 82
`
`THRESHOLD
`:
`DETECTION DATA
`DISPLAYRAA LATCH-120
`160-Vth DATA LATCHUNIT
`GRADATION SIGNAL
`140- Vth ADC Vth DAC -150
`SiN-130
`DETECTION
`VOLTAGE Wodec
`180-
`SWITCHING
`CONTROL -
`SIGNALAZ (L)
`
`
`
`181
`
`f (H)
`
`SL
`
`D
`
`WCVth 13
`
`OEL
`
`1
`
`C
`
`FIG.5
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 007
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 6 of 36
`
`US 7,907,137 B2
`
`
`
`B.
`
`THRESHOLD VOLTAGE
`BOUNDARY
`EL LOADLINE
`CURRENT BETWEEN
`ORAN AND SOURCE
`
`IN CASE OF
`Vgsmax
`
`IN CASE OF
`Vgs1
`
`IN CASE OF
`Vgs2 (<Vgs1)
`
`0.0E:00;
`
`With 13max
`
`Vodsmax
`
`VOLTAGE Vds BETWEEN DRAIN AND SOURCE (V)
`
`FIG.6
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 008
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 7 of 36
`
`US 7,907,137 B2
`
`DISPLAY DRIVE PERIOD Ee
`(ONE TREATMENT CYCLE PERIOD)
`WRITING
`PRE-CHARGEoPERAftöN
`PERIODTth PERIOD Twrt
`LIGHT EMITTING
`OPERATION PERIOD Tem
`
`SWITCHING CONTROL
`SIGNAL AZ
`
`
`
`PRE-CHARGE VOLTAGE
`Vpre (DATA LINEDL)
`
`GRADATION CURRENT data
`(DATA LINE DL)
`
`SELECTION SGNAL SSel
`
`POWER SUPPLY
`VOLTAGEWSC
`
`Vs (GND) -
`VOLTAGEWS BETWEEN GATE
`AND SOURCE OF THINFILM
`:
`TRANSISTORT13
`With 3-----1------
`(BOTH-ENDS PoteNTIAL
`O ririri-r
`Vc OF CAPACITOR Cs)
`LIGHT EMISSION DRIVENG
`CURRENT lem
`
`
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 009
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 8 of 36
`
`US 7,907,137 B2
`
`THRESHOLD
`COMPENSATION
`DATA
`
`FRAME MEMORY
`
`170
`------
`
`DISPLAY -
`( DATA)
`
`SHIFT REGISTER/
`NARESISTERNIT
`DATA REGISTER UNIT
`THRESHOLD
`COMPENSATION
`DATA
`160-Vth DATA LATCHUNIT
`ISPLAYBATALATCH-120
`
`110
`
`140
`
`150 AASISNA. 130
`With ADC With DAC
`PRE-CHARGE
`VOLTAGE Vpre
`
`180-
`YS
`SIGNALAZ (H)
`
`1.
`181
`
`
`
`\
`
`182
`
`N
`
`Y
`
`100
`
`VSC Wvcom)
`
`-1
`PX
`
`VcomigND)
`
`FIG.8
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 010
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 9 of 36
`
`US 7,907,137 B2
`
`-----
`
`FRAME MEMORY
`
`DISPLAY
`DATA
`
`i.
`
`SHIFT REGISTER/
`DATAREGISTER UNIT
`ATA REGISTER UNIT
`
`170
`---
`
`110
`
`:
`
`160-Vth DATA LATCHUNIT
`140
`With ADC With DAC
`
`DISPLAY
`DATA
`DISPLAYRAIA LATCH-120
`GRADATIONSIGNAL
`150 GENERATION UNIT
`130
`
`180 -
`
`
`
`SWITCHING
`CONTROL -
`SIGNALAZ (H)
`
`Wrt
`
`GRADATION
`CURRENT data
`
`100
`
`WL
`
`VSC ?t Svcom)
`
`r"
`
`OEL
`
`O
`Vcom (GND)
`
`Vc=Vth 13--Vodata
`1
`
`PX
`
`FIG.9
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 011
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 10 of 36
`
`US 7,907,137 B2
`
`-----
`
`FRAME MEMORY
`
`...
`DISPLAY................
`( DATA)
`
`SHIFT REGISTER/
`nATARESISTERNIT
`DATA REGISTER UNIT
`
`170
`--
`
`110
`
`160-Vth DATA LATCHUNIT
`140
`Vth ADC Vth DAC
`
`DISPLAYEAIALATCH-120
`GRADATION SIGNAL
`150 GENERATION UNIT
`130
`
`180-
`YS
`SIGNALAZ (H)
`
`Lo e
`in 182
`
`O
`/
`181
`
`N
`183
`
`---------------
`
`
`
`Stil ()
`
`s.
`
`DL
`
`YU
`100
`
`VL
`
`Vsc (H).
`(Vsc>Vcom)
`
`DC
`
`Vc=Vth13+Vdata Y
`- YOEL
`-1
`VcomigND)
`PX
`
`FIG.10
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 012
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 11 of 36
`
`US 7,907,137 B2
`
`-
`
`FRAME MEMORY
`
`.
`DISPLAY.............
`( DATA)
`
`SHIFT REGISTER/
`ATARSISTENT
`DATA REGISTER UNIT
`
`170
`---
`
`110
`
`
`
`180-
`
`SWITCHING
`CONTROL -
`SIGNALAZ (H)
`
`C
`/
`182 r
`
`CH
`(ON)
`
`190
`DETECTINGVOLTAGE
`D55SENSSEE
`POWER SOURCE
`DETECTING
`VOLTAGE Vpw
`
`O
`
`
`
`181
`---
`
`Ssel
`Se
`H (H)
`
`SL
`
`pv
`
`Y
`100
`
`VL
`
`Vsc (L
`'vcom)
`
`DC
`
`(ON)
`
`DL
`
`- - - - a am - - - - -
`
`Vc=Vcp> Vth 13
`
`OEL
`
`-1.
`PX
`
`O
`Vcom (GND)
`
`FIG.11
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 013
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 12 of 36
`
`US 7,907,137 B2
`
`DISPLAY DRIVE PERIOD Ea?
`(ONE TREATMENT CYCLE PERIOD)
`->
`WRITING
`PRE-CHARGEOPERATION
`PERIODTth PERIOD Twrt
`LIGHT EMITTING
`OPERATION PERIOD Tem
`
`SWITCHING CONTROL
`SIGNAL AZ
`
`
`
`PRE-CHARGE VOLTAGE
`Vpre (DATA LINE DL)
`
`Vpre
`
`NONIGHTEM.ING
`DISPLAY VOLTAGE WZero
`(DATA LINE DL)
`
`vzero.i.
`
`
`
`SELECTION SIGNAL SSel
`
`POWER SUPPLY
`VOLTAGE VSC
`
`Veri-i-
`Vs (GND)
`VOLTAGEWCS BETWEEN GATE
`AND SOURCE OF THEN FILM
`TRANSISTOR Tr13
`(BOTH-ENDSPOTENTIAL
`Vc OF CAPACITOR Cs)
`LIGHT EMISSION DRIVING
`CURRENT lem
`
`
`
`With 13----
`O -----------
`imsb ----------- i---------i----------------------------------------------------
`O
`
`FIG. 12
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 014
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 13 of 36
`
`US 7,907,137 B2
`
`---
`
`FRAME MEMORY
`
`170
`------
`
`DISPLAY
`DATA
`
`i.
`
`SHIFT REGISTER/
`DATA REGISTER UNIT
`
`DISPLAY
`DATA
`DISPLAYRIA LATCH-120
`160-Vth DATA LATCH UNIT
`GRADATION SIGNAL
`140
`Vth ADC Vth DAC -150
`AiN 130
`NON-LGHT EMTTING
`DISPLAY VOLTAGE WZero
`
`180-
`S
`SIGNALAZ (H)
`
`
`
`O AC
`N1 82
`
`YU
`
`-1
`PX
`
`O
`Vcom (GND)
`
`FIG.13
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 015
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 14 of 36
`
`US 7,907,137 B2
`
`r
`
`FRAME MEMORY
`
`------
`DISPLAY..............
`( DATA)
`
`SHIFT REGISTER
`nATARESISTERNIT
`DATA REGISTER UNIT
`
`170
`---
`
`110
`
`160-Vth DATA LATCH UNIT
`140 - Vth ADC
`
`DISPLAYRIA LATCH-120
`GRADATION SIGNAL
`150
`AiNN-130
`
`180 - T Lo
`C
`SG
`SIGNALAZ (H)
`
`182
`
`O
`N
`1.
`183
`181
`---------------
`
`
`
`Sil (L)
`
`SL
`
`DL
`
`Y
`
`100
`
`WL
`
`Vsc (H)
`(Vsc>Vcom)
`
`DC
`
`PX
`
`VcomigND)
`
`FIG.14
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 016
`
`

`

`U.S. Patent
`
`_.Ia
`
`US 7,907,137 B2
`
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`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 017
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 017
`
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 16 of 36
`
`US 7,907,137 B2
`
`
`
`OUTPUT CIRCUIT UNIT
`
`OUTPUT CIRCUIT UNIT
`
`SHIFT RESISTER CIRCUIT
`
`
`
`EKOHTOS HEAWOdHEATHCI \/ IVCI /ældA/AdA3)NINNVOS
`
`
`TVNº)IS TOHINOOaudáAdÄ? | TVN50||S TOHJENOS)
`
`
`XOM 1SM BOM?????TI L 30S_1SS X9$
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 018
`
`

`

`S.U
`
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`U.S. Patent
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`5, 2011
`Mar. 1
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`U.S. Patent
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`Mar. 15, 2011
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`LG Display Co., Ltd.
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`

`U.S. Patent
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`Mar. 15, 2011
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`US 7,907,137 B2
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`

`U.S. Patent
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`Mar. 15, 2011
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`Sheet 22 of 36
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`US 7,907,137 B2
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`LG Display Co., Ltd.
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`LG Display Co., Ltd.
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`

`U.S. Patent
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`Mar. 15, 2011
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`US 7,907,137 B2
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`U.S. Patent
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`Mar. 15, 2011
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`Sheet 25 of 36
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`US 7,907,137 B2
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`Page 027
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`LG Display Co., Ltd.
`Exhibit 1001
`Page 027
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`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 26 of 36
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`US 7,907,137 B2
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`LG Display Co., Ltd.
`Exhibit 1001
`Page 028
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`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 27 of 36
`
`US 7,907,137 B2
`
`
`
`LG Display Co., Ltd.
`Exhibit 1001
`Page 029
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
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`Sheet 28 of 36
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`US 7,907,137 B2
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`U.S. Patent
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`Mar. 15, 2011
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`US 7,907,137 B2
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`LG Display Co., Ltd.
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`U.S. Patent
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`Mar. 15, 2011
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`Sheet 30 of 36
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`US 7,907,137 B2
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`U.S. Patent
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`Mar. 15, 2011
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`US 7,907,137 B2
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`Page 033
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`

`U.S. Patent
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`Mar. 15, 2011
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`Sheet 32 of 36
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`

`

`U.S. Patent
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`Mar. 15, 2011
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`Sheet 33 of 36
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`US 7,907,137 B2
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`U.S. Patent
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`Mar. 15, 2011
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`Sheet 34 of 36
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`US 7,907,137 B2
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`Page 036
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`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 35 of 36
`
`US 7,907,137 B2
`
`DISPLAY
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`LG Display Co., Ltd.
`Exhibit 1001
`Page 037
`
`

`

`U.S. Patent
`
`Mar. 15, 2011
`
`Sheet 36 of 36
`
`US 7,907,137 B2
`
`Vpix
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`LG Display Co., Ltd.
`Exhibit 1001
`Page 038
`
`

`

`US 7,907,137 B2
`
`1.
`DISPLAY DRIVE APPARATUS, DISPLAY
`APPARATUS AND DRIVE CONTROL
`METHOD THEREOF
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`
`This application is based upon and claims the benefit of
`priority from prior Japanese Patent Applications No. 2005
`101905, filed Mar. 31, 2005; and No. 2005-105373, filed Mar.
`31, 2005, the entire contents of both of which are incorporated
`herein by reference.
`
`BACKGROUND OF THE INVENTION
`
`10
`
`15
`
`2
`As shown in FIG. 35, a conventional organic EL display
`apparatus which is of an active matrix type generally has a
`configuration comprising: a display panel 110P in which a
`plurality of display pixels EMp are arranged in a matrix in the
`vicinity of intersections of a plurality of scanning lines (selec
`tion lines) SLp and a plurality of data lines (signal lines) DLp
`arranged to respectively extend in a row direction and a col
`umn direction; and a scanning driver 120P which is connected
`with the scanning lines SLp; and a data driver 130P which is
`connected with the data lines DL.
`As shown in FIG. 36, each of the display pixels EMp
`comprises a pixel drive circuit DCp. The circuit DCp includes
`a thin film transistor (TFT) Tr111 having a gate terminal
`connected with the scanning line SLp and source and drain
`terminals respectively connected with the data line DL and a
`contact point N111, and a thin film transistorTr112 having a
`gate terminal connected with the contact point N111 and a
`Source terminal receiving a predetermined power source Volt
`age Vdd. An organic EL element OEL has an anode terminal
`connected with a drain terminal D of the thin film transistor
`Tr112 of the pixel drive circuit DCp and a cathode terminal
`receiving a ground potential Vgnd lower than the power Sup
`ply voltage Vdd. In FIG. 36, reference numeral Cp denotes a
`capacitor formed between the gate and the source terminals of
`the thin film transistor Tr112.
`In the display apparatus comprising the display panel 110P
`constituted by the display pixels EMp having Such a configu
`ration, first, an ON-level scanning signal Voltage Ssel is
`sequentially applied to the Scanning line SLp in each row
`from the scanning driver 120P to turn on the thin film tran
`sistorTr111 of the display pixel EMp (the drive circuit DCp)
`in each row, thereby setting the display pixel EMp in a selec
`tion state.
`In synchronization with this selection timing, a gradation
`Voltage Vpix having a Voltage value corresponding to display
`data is generated by the data driver 130P and applied to the
`data line DLp in each column, and the gradation Voltage Vpix
`is thereby applied to the contact point N111 (that is, the gate
`terminal of the thin film transistorTr112) through the thin film
`transistor Tr111 of each display pixel EMp (the drive circuit
`DCp).
`As a result, the thin film transistor Tr112 is turned on in a
`conductive state (i.e., a conductive state corresponding to the
`gradation Voltage Vpix) corresponding to the potential (in a
`precise sense, a potential difference between the gate and the
`source) of the contact point N111. Thus, a predetermined
`driving current flows to the ground Voltage Vgnd from the
`power source voltage Vdd through the thin film transistor
`Tr112 and the organic EL element OEL. Consequently, the
`organic EL element OEL operates to emit light with a lumi
`nance gradation corresponding to display data (the gradation
`Voltage Vpix).
`Subsequently, an off-level scanning signal Voltage Ssel is
`applied to the Scanning line SLp from the Scanning driver
`120P. Thus, the thin film transistor Tr111 of the display pixel
`EMp in each row is turned off, the display pixel EMp is set to
`a non-selective state, and the data line DLp and the drive
`circuit DCp are electrically disconnected. At this time, the
`thin film transistor Tr112 maintains an ON state in such a
`manner that a predetermined Voltage is applied between the
`gate and the source terminals of the thin film transistor Tr112
`based on a potential which has been applied to the gate ter
`minal (the contact point N111) and held in the capacitor Cp.
`Therefore, in the same manner as the light emitting opera
`tion in the selective state, a predetermined driving current
`flows to the organic EL element OEL through the thin film
`transistor Tr112 from the power supply voltage Vdd, thereby
`
`1. Field of the Invention
`The present invention relates to a display drive apparatus, a
`display apparatus provided with the display drive apparatus,
`and a drive control method thereof, and more particularly, to
`a display drive apparatus which is applicable to a display
`panel formed by arranging a plurality of current control type
`optical elements which are driven by being supplied with a
`current corresponding to display data, a display apparatus
`provided with the display drive apparatus, and a drive control
`method thereof.
`2. Description of the Related Art
`In recent years, light weight and thin type display devices
`which consume a lower amount of electric power are con
`spicuously prevalent as monitors and displays of personal
`computers and video equipment. In particular, liquid crystal
`display (LCD) apparatuses are widely applied as display
`devices for mobile phones, digital cameras, personal data
`assistances (PDAs), and portable devices (mobile handsets)
`Such as electronic dictionaries.
`As a next-generation display device which follows such an
`LCD apparatus, research and development have been briskly
`made toward a full-scale popularization of a self-luminous
`type display device (a self-luminous type display) provided
`with a display panel in which organic electroluminescent
`elements (organic EL elements), inorganic electrolumines
`cent elements (inorganic EL elements) or optical elements
`Such as light emitting diodes (LEDs) are arranged in a matrix.
`In particular, a self-luminous type display to which an
`active matrix drive mode is applied has a higher display
`response speed than that of the above-described liquid crystal
`display. Further, the self-luminous type display does not have
`viewing angle dependency, and can achieve an increase in
`luminance/contrast and in fineness of a display image quality.
`Furthermore, the self-luminous type display does not require
`a backlight as different from the liquid crystal display, and
`hence the self-luminous type display has very advantageous
`characteristics in the application to portable devices that a
`further reduction in a thickness and a weight and/or a further
`decrease in power consumption is possible.
`Then, in Such a self-luminous type display, various driving
`control mechanisms and/or control methods for controlling
`an operation of the optical elements have been proposed.
`FIG. 35 is a schematic structural diagram showing a pri
`mary part of a conventional self-luminous display which is of
`a Voltage control active matrix type.
`FIG. 36 is an equivalent circuit diagram showing a struc
`tural example of a display pixel which is applicable to the
`conventional self-luminous type display.
`Here, FIG. 35 shows a circuit configuration of a display
`pixel comprising a light emitting element formed of an
`organic EL element OEL as the optical element.
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`LG Display Co., Ltd.
`Exhibit 1001
`Page 039
`
`

`

`US 7,907,137 B2
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`maintaining the light emitting operation. This light emitting
`operation is controlled to continue for, e.g., one frame period
`until the gradation Voltage Vpix corresponding to the next
`display data is applied to (written in) the display pixel EMP in
`each row.
`Such a drive control method is referred to as a voltage
`gradation specification mode (or a Voltage gradation specifi
`cation drive) since a current value of a driving current which
`flows to the organic EL element OEL is controlled to perform
`a light emitting operation with a predetermined luminance
`gradation by adjusting a Voltage value of the gradation Volt
`age Vpix applied to each display pixel EMp (specifically, the
`gate terminal of the thin film transistor Tr112 of the drive
`circuit DCp).
`In the drive circuit DCp as shown in FIG. 36, the current
`path is connected in series to the organic EL element OEL, so
`that the element characteristics (particularly, the threshold
`voltage characteristics) of the thin film transistor Trr112 for
`drive which allows the flow of a driving current correspond
`ing to the display data (gradation Voltage) may change (shift)
`depending on the usage time, the drive history and the like. In
`Such a case, a relation between a gate Voltage (a potential of
`the contact point 111) and a driving current (a current
`between the source and the drain terminals) which flows
`between the source and the drain terminals changes, and
`thereby a current value of a driving current which flows at a
`predetermined gate Voltage fluctuates (for example,
`decreases). As a result, it becomes difficult to stably realize a
`light emitting operation for a long period with an appropriate
`luminance gradation corresponding to the display data.
`Furthermore, in the case where variation occurs in element
`characteristics (the threshold voltage) of the thin film transis
`tors Tr111 and Tr112 in the display panel 110P for each
`display pixel EMp (the drive circuit DCp), or in the case
`where variation occurs in the element characteristics of the
`transistors Tr111 and Tr112 for each display panel 110P
`depending on the manufacture lots, the current value of the
`driving current largely varies for each display pixel or each
`display panel in the drive circuit which is of a Voltage grada
`tion specification mode, so that an appropriate gradation con
`trol becomes unable to be performed.
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`BRIEF SUMMARY OF THE INVENTION
`
`The present invention has advantages of compensating for
`change and variation in the element characteristics of the
`drive element and providing a favorable and uniform display
`image quality in a display drive apparatus and a display appa
`ratus provided with the display drive apparatus, the display
`drive apparatus operating, in accordance with display data, an
`optical element of a display pixel provided with an optical
`element and a drive element for Supplying a driving current to
`the optical element.
`In order to attain the above advantages, a display drive
`apparatus according to the present invention comprises: a
`gradation signal generation circuit which generates a grada
`tion signal corresponding to a luminance gradation of the
`display data and Supplies the gradation signal to a display
`pixel; a threshold voltage detection circuit which detects a
`threshold voltage peculiar to a drive element of the display
`pixel; and a compensation Voltage application circuit which
`generates a compensation Voltage for compensating for the
`threshold voltage of the drive element on the basis of the
`threshold Voltage and applies the compensation Voltage to the
`drive element.
`The display drive apparatus may further comprise: a
`memory circuit which stores threshold data corresponding to
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