`
`
`(19) United States
`
`
`
`
`
`
`
`
`(12) Patent Application Publication (10) Pub. No.: US 2008/0007679 A1
`
`
`
`
`
`
`
`
`Ochiai et al.
`(43) Pub. Date: Jan. 10, 2008
`
`
`
`US 20080007679Al
`
`
`
`
`
`
`(54) TRANSFLECTIVE LIQUID CRYSTAL
`DISPLAY DEVICE
`
`
`
`
`
`(75)
`
`
`
`Inventors:
`
`
`
`
`
`
`
`Takahiro Ochiai, Chiba (JP);
`
`
`
`
`Takayuki Nakao, Atsugi (JP);
`
`
`
`
`Daisuke Sonoda, Chiba (JP);
`
`
`
`Hidekazu Miyake, Mobara (JP);
`
`
`
`
`Toshio Miyazawa, Chiba (JP);
`
`
`
`
`Masahiro Maki, Mobara (JP);
`
`
`
`
`Tohru Sasaki, Mobara (JP)
`
`
`
`
`
`
`Correspondence Address:
`
`
`Stanley P. Fisher
`Reed Smith LLP
`
`
`
`
`
`
`
`
`Suite 1400, 3110 Fairview Park Drive
`
`
`
`Falls Church, VA 22042-4503
`
`
`
`
`(73) Assignee:
`
`
`
`
`
`Hitachi Displays, Ltd.
`
`
`
`
`
`(21) Appl. No.:
`
`
`
`11/812,770
`
`
`
`(22)
`
`(30)
`
`
`
`
`
`Filed:
`
`
`
`
`
`Jun. 21, 2007
`
`
`
`
`
`
`Foreign Application Priority Data
`
`
`
`
`
`Jul. 7, 2006
`
`
`
`
`
`(JP) ................................. 2006-188258
`
`
`
`
`
`DPR
`
`
`
`Publication Classification
`
`
`
`
`
`
`(51)
`
`
`
`
`
`Int. Cl.
`
`
`
`(2006.01)
`G02F 1/1335
`
`
`
`
`(52) use. ....................................................... 349/114
`
`
`ABSTRACT
`(57)
`
`
`
`
`
`
`
`The manufacturing yield of transflective liquid crystal dis-
`
`
`
`
`
`
`
`
`play devices is to be enhanced. In a transflective liquid
`
`
`
`
`
`
`
`crystal display device including a liquid crystal display
`
`
`
`
`
`
`
`
`panel having a pair of substrates and a liquid crystal layer
`
`
`
`
`
`
`
`
`
`held between the pair of substrates, the liquid crystal display
`
`
`
`
`
`
`
`panel has a plurality of subpixels each having a transmissive
`
`
`
`
`
`
`
`
`
`
`part and a reflective part, wherein one of the pair of
`
`
`
`
`
`
`
`
`substrates has: an active element; a first
`insulating film
`
`
`
`
`
`
`
`disposed in a higher layer than the electrode of the active
`
`
`
`
`
`
`
`
`element and having a first contact hole; a counter electrode
`
`
`
`
`
`
`
`
`disposed in a higher layer than the first insulating film; a
`
`
`
`
`
`
`
`reflective electrode disposed in the reflective part in a higher
`
`
`
`
`
`
`
`
`layer than the counter electrode; a second insulating film
`
`
`
`
`
`
`
`
`disposed in a higher layer than the counter electrode and the
`
`
`
`
`
`
`
`
`reflective electrode and having a second contact hole; a pixel
`
`
`
`
`
`
`
`
`electrode disposed in a higher layer than the second insu-
`
`
`
`
`
`
`
`lating film; and an electroconductor formed in the first
`
`
`
`
`
`
`
`contact hole and electrically connected to the electrode of
`
`
`
`
`
`
`
`
`the active element, and the pixel electrode is electrically
`connected to the electroconductor via the second contact
`
`
`
`
`
`
`
`hole.
`
`
`CT
`
`
`
`PAS3
`
`
`
`0000
`0000
`
`
`
`
`ooooooooooooooN”
` WWWIW'
`
`
`PAS4
`
`RET1
`
`
`
`
`
`
`
`
`
`
`Page 1 of 34
`
`Tianma Exhibit 1005
`
`Page 1 of 34
`
`Tianma Exhibit 1005
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 1 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`
`
`Page 2 of 34
`
`Page 2 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 2 of 22
`
`
`
`US 2008/0007679 A1
`
`FIG.1 B
`
`
`
`
`
`
`
`D:
`
`Page 3 of 34
`
`\I/15(m:4u
`
`
`
`PIX(53)
`
`
`
`52
`
`Page 3 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 3 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.2
`
`
`
`
`
`PIX(51)
`
`
`
`
`
`CT
`
`15
`
`
`
`14
`
`13
`
`
`
`
`12
`
`
`
`
`
`11
`
`SUB1
`
`
`
`
`
`Page 4 of 34
`
`Page 4 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 4 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.4
`
`
`
`PlX(52)
`
`
`
`‘7
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 5 of 34
`
`Page 5 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 5 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`PlX(51)
`
`
`
`
`
`03 03 CD
`
`0:) 03 CD
`
`
`
`
`:-I/Ii5’:
`
`CT
`
`'\!l'\'1!l"1!l'QM
`
`
`Page 6 of 34
`
`Page 6 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 6 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`15
`
`
`
`14
`
`
`
`13
`
`SUB1
`
`
`
`
`12
`
`
`11
`
`
`
`
`
`Page 7 of 34
`
`Page 7 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 7 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.6C
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`CH2a
`
`
`
`CH1
`
`
`
`Poly-Si
`
`
`
`SUB‘
`
`
`
`
`
`
`CH2a
`
`
`
`CH1
`
`
`
`Poly-Si
`
`
`
`SUB1
`
`
`
`Page 8 of 34
`
`Page 8 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 8 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`
`
` RAL
`
`\:
`
`§
`
`‘ \\
`
`
`
`\\
`\\
`
`
`
`Page 9 of 34
`
`Page 9 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 9 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`Page 10 of 34
`
`Page 10 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 10 of 22
`
`
`
`US 2008/0007679 A1
`
`FIG.8
`
`
`
`
`
` H
`
`
`4—»
`
`'va
`
`
`
`
`-II-
`
`Ill!—
`
`nit/Ali
`
`
`Vb
`-)_
`
`. \
`
`—I_—
`
`
`
`
`
`
`
`7
`
`
`
`PlX(n,k)
`
`CTk
`
`
`CTk+1
`
`
`
`P1x(n,k)
`
`
`Gm
`
`
`
`PIX(n,k)
`
`
`
`Page 11 of 34
`
`Page 11 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 11 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.9
`
`
`
`
`
`
`VcomH
`
`S
`
`
`
`1/
`
`r-- -1
`
`I
`I
`
`I i
`
`I:
`
`L. _ _ _ _ _l
`
`
`
`
`
`
`VLp
`
`
`
`VHp
`
`
`
`VLp+1
`
`VHp+1
`
`
`
`
`
`VLp+2
`
`VHp+2
`
`
`
`L__ -4
`
`
`----1
`
`I
`
`
`x
`
`I
`
`I }
`
`I:
`
`
`L—————'I
`I
`I
`I
`L__ -4
`
`
`r----fi
`
`I
`I
`
`II
`
`: :
`
`
`I—————-JI
`I
`I
`I
`L__ _J
`
`
`
`
`CTk
`
`
`
`:TM4
`
`
`
`Tk+2
`
`Page 12 of 34
`
`Page 12 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 12 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.1O
`
`
`
`
`
`CH2b
`
`
`
`CH3b
`
`
`
`‘7
`
`
`
`
`
`I'i'.\
`Hfl%%%%%~
`
`
`
`DD1
`
`RAL2
`
`
`
`CT
`
`
`
`
`
`16
`
`
`
`15
`
`Page 13 of 34
`
`Page 13 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 13 of 22
`
`
`
`US 2008/0007679 A1
`
`FIG.11
`
`
`
`
`
`
`
`
`
`PIX
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`2
`
`
`24
`
`
`2g24
`g?
`
`‘———----—--
`
`
`
`
`
`CT
`
`
`
`PIX
`
`
`
`Page 14 of 34
`
`Page 14 of 34
`
`
`
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 14 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`V-CT-H
`
`Page 15 of 34
`
`Page 15 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 15 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 16 of 34
`
`Page 16 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 16 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.14
`
`
`
`
`
`PIX
`
`
`
`CT
`
`
`
`
`RAL
`
`
`
`Page 17 of 34
`
`Page 17 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 17 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`
`
`17
`
`CT
`
`
`RAL
`
`
`
`16
`
`14
`
`
`
`13
`
`
`
`
`
`12
`
`
`
`
`SUB1
`
`11
`
`Page 18 of 34
`
`Page 18 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 18 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
`POL2
`
`
`
`
`
`FIR
`
`SUBZ
`
`
`
`18
`
`
`RET
`
`MR
`
`0R2
`
`
`
`EFS
`
`0R1
`
`PIX
`
`17
`
`
`Wkfilf'filf'fil 4%" RAL
`
`II III-E CT
`
`”WWW/WWW 16
`
`
`LC
`
`15
`
`14
`
`13
`
`
`
`
`
`
`
`
`
`
`
`
`12
`
`
`
`11
`SUB1
`
`
`
`
`DD
`
`POL1
`
`
`
`Page 19 of 34
`
`Page 19 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 19 0f 22
`
`
`
`US 2008/0007679 A1
`
`
`
` G
`
`
`
`
`
`I
`
`DD
`
`
`
`
`CH4a
`
`
`
`D
`
`
`G'
`
`
`
`PIX
`
`RAL
`
`
`
`
`1'
`
`
`CH3a
`
`
`PD
`
`Poly-Si
`
`
`
`CH1
`
`
`
`D
`
`Page 20 of 34
`
`Page 20 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 20 of 22
`
`
`
`US 2008/0007679 A1
`
`FIG.19
`
`
`
`PIX
`
`
`
`COM
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`RAL
`
`
`
`COM
`
`
`
`
`
`
`Km
`
`
`Page 21 of 34
`
`Page 21 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 21 0f 22
`
`
`
`US 2008/0007679 A1
`
`FIG.21
`
`
`
`PIX
`
`
`
`
`
`
`§\\\\\\\\\\\\‘§ WWW §\\\\\\\\\\\\
`RAL
`
`
`—=— COM
`
`
`
`SUB1
`
`3O 4—i—V 31
`
`
`
`DPR
`
`
`
`
`
`
`
`
`WWWWWW \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\‘ SUBZN
`
`WWW0R2
`..N CFR
`...........
`00
`..............
`
`
`
`
`
`
`V 000000000000000 0 0 Q Q Q Q 00:: 2:1
`
`
`
`
`
`
`
`
`
`
`PA83 W /\/ PAS1
`
`
`
`
`
`
`\\\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\
`
`\\\\\\\\\\\\\\\\\\\\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\{§
`
`
`
`\\ \\\\\\\\\\\\.
`/////////////////////////////////////////
`//////////////////////////.\"/////////////
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 22 of 34
`
`
`
`PAS4
`
`
`
`RET1
`
`Page 22 of 34
`
`
`
`
`
`Patent Application Publication
`
`
`
`
`
`
`
`Jan. 10, 2008 Sheet 22 of 22
`
`
`
`US 2008/0007679 A1
`
`
`
`FIG
`
`
`
`FIG
`
`
`24
`
`15
`
`
`
`DD1
`
`
`
`Page 23 of 34
`
`Page 23 of 34
`
`
`
`
`
`
`US 2008/0007679 A1
`
`
`
`Jan. 10, 2008
`
`
`
`
`
`
`
`
`
`
`
`
`is formed, and a driving voltage is applied to the pixel
`
`
`
`
`
`
`electrode (PIX) through this contact hole.
`
`
`
`
`
`
`
`[0012] However,
`the transflective liquid crystal display
`
`
`
`
`
`
`
`device disclosed in Japanese Patent Application No. 2005-
`
`
`
`
`
`
`
`
`322049 involves a problem (2) that, in boring a hole in the
`
`
`
`
`
`
`
`
`counter electrode (CT) to apply a driving voltage to the pixel
`
`
`
`
`
`
`
`
`electrode (PIX) arranged on the liquid crystal side of one of
`
`
`
`
`
`
`
`
`the substrates and forming a contact hole therein, non-
`
`
`
`
`
`
`
`display parts increase and the transmissivity drops.
`
`
`
`
`
`
`
`[0013] Therefore, to solve this problem (2), the present
`
`
`
`
`
`
`applicant has already applied for a patent on a transflective
`
`
`
`
`
`
`
`liquid crystal display device having a novel pixel structure
`
`
`
`
`
`
`(see Japanese Patent Application No. 2006-109659).
`
`
`
`
`
`
`
`[0014] This transflective liquid crystal display device on
`
`
`
`
`
`
`
`which a patent is pending is intended to prevent the trans-
`
`
`
`
`
`
`
`
`missivity from dropping by using the gap between opposing
`
`
`
`
`
`
`
`
`counter electrodes (CT) as the opening in the counter
`
`
`
`
`
`
`
`
`electrodes (CT) required for the formation of the contact
`hole.
`
`
`
`
`
`
`SUMMARY OF THE INVENTION
`
`
`
`
`
`
`
`TRANSFLECTIVE LIQUID CRYSTAL
`DISPLAY DEVICE
`
`
`
`
`
`CLAIM OF PRIORITY
`
`
`
`
`
`
`
`
`
`
`
`
`[0001] The present application claims priority from Japa-
`
`
`
`
`
`
`
`nese Application JP 2006-188258 filed on Jul. 7, 2006, the
`
`
`
`
`
`
`content of which is hereby incorporated by reference into
`
`
`this application.
`
`BACKGROUND OF THE INVENTION
`
`
`
`
`
`
`
`
`
`
`1. Field of the Invention
`[0002]
`
`
`
`
`
`
`
`[0003] The present invention relates to transflective liquid
`
`
`
`
`
`
`
`crystal display devices, and more particularly to a transflec-
`
`
`
`
`
`
`
`tive liquid crystal display device of an in-plane switching
`
`
`
`
`type or a vertical alignment type.
`
`
`
`
`
`
`[0004]
`2. Description of the Related Art
`
`
`
`
`
`
`
`[0005] Transflective liquid crystal display devices each
`
`
`
`
`
`
`
`
`having a transmissive part and a reflective part
`in one
`
`
`
`
`
`
`
`
`subpixel are used as display units for mobile devices.
`
`
`
`
`
`
`
`
`Such transflective liquid crystal display devices use
`[0006]
`
`
`
`
`
`
`
`
`
`a system in which electric fields are applied to liquid crystals
`
`
`
`
`
`
`
`held between a pair of substrates in a direction normal to the
`
`
`
`
`
`
`
`planes of the paired substrates to drive the liquid crystals. In
`
`
`
`
`
`
`
`
`this case, to match the characteristics of the transmissive part
`
`
`
`
`
`
`
`
`
`and the reflective part, a level gap is provided between the
`
`
`
`
`
`
`
`
`
`transmissive part and the reflective part, and further a phase
`
`
`
`
`
`
`differential plate is arranged between a polarization plate
`
`
`
`
`
`and the liquid crystal layer.
`
`
`
`
`
`
`
`
`[0007] On the other hand, IPS type transflective liquid
`
`
`
`
`
`
`
`
`crystal display devices are also known, in each of which
`
`
`
`
`
`
`
`
`pixel electrodes (PIX) and counter electrodes (CT) are
`
`
`
`
`
`
`
`
`
`
`formed over the same substrate, and gray scale levels are
`
`
`
`
`
`
`
`controlled by applying electric fields to these liquid crystals
`
`
`
`
`
`
`
`
`
`
`by rotating them within the substrate plane. For this reason,
`
`
`
`
`
`
`
`
`these devices have a significant feature that the relative
`
`
`
`
`
`
`
`
`
`shades of the display image are not reversed when the screen
`
`
`
`
`
`
`
`
`is looked at askew. To take advantage of this feature, it is
`
`
`
`
`
`
`proposed to structure a transflective liquid crystal display
`
`
`
`
`
`
`
`
`device by using an IPS type liquid crystal display device.
`
`
`
`
`
`[0008] However, structuring a transflective liquid crystal
`
`
`
`
`
`
`
`display device by using an IPS type liquid crystal display
`
`
`
`
`
`
`
`device involves a problem (1) that, when the transmissive
`
`
`
`
`
`
`
`part is normally black, the reflective part becomes normally
`
`
`
`
`
`
`
`
`white, namely the relative shades are reversed between the
`
`
`
`
`
`
`transmissive part and the reflective part.
`
`
`
`
`
`
`
`
`
`In view of this point, the present applicant has
`[0009]
`
`
`
`
`
`
`already applied for a patent on a transflective liquid crystal
`
`
`
`
`
`
`
`display device having a new pixel structure (see Japanese
`
`
`
`
`
`
`Patent Application No. 2005 -322049) intended to solve this
`
`
`problem (1).
`
`
`
`
`
`
`
`[0010] This transflective liquid crystal display device on
`
`
`
`
`
`
`
`
`which a patent is pending has a pixel structure for each
`
`
`
`
`
`
`
`subpixel in which an independent counter electrode for each
`
`
`
`
`
`
`
`
`
`of the transmissive part and the reflective part is provided
`
`
`
`
`
`
`
`against a common pixel electrode of the transmissive part
`
`
`
`
`
`
`
`
`
`and the reflective part, and reversal of the relative shades
`
`
`
`
`
`
`between them is prevented by applying different reference
`
`
`
`
`
`
`
`voltages (a counter voltage and a common voltage) to the
`
`
`
`
`
`
`transmissive part and the reflective part.
`
`
`
`
`
`
`
`
`
`
`[0011]
`In the IPS type liquid crystal display device, the
`
`
`
`
`
`
`
`pixel electrode (PIX) is disposed on the liquid crystal side of
`
`
`
`
`
`
`
`
`one of the paired substrates. In this arrangement, a hole is
`
`
`
`
`
`
`
`
`bored in the counter electrode (CT), in which a contact hole
`
`
`
`
`
`
`
`
`
`
`
`
`Page 24 of 34
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`[0015] The present inventors studied the transflective liq-
`
`
`
`
`
`
`
`uid crystal display device described in Japanese Patent
`
`
`
`
`
`
`Application No. 2006-109659, and found the following
`
`problems.
`
`
`
`
`
`
`
`FIG. 23 shows the essential part of the sectional
`[0016]
`
`
`
`
`
`
`structure of the connecting part which electrically connects
`
`
`
`
`
`
`the electrode of an active element to a pixel electrode in the
`
`
`
`
`
`
`
`
`pixel part of the liquid crystal panel in the transflective liquid
`
`
`
`
`
`
`crystal display device of Japanese Patent Application No.
`
`
`
`
`
`
`
`2006-109659, and FIG. 24, the essential part ofthe sectional
`
`
`
`
`
`
`structure of the connecting part which electrically connects
`the electrode of an active element to a counter electrode via
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`an ITO film in the peripheral circuit part of the liquid crystal
`
`
`
`
`
`
`
`panel in the transflective liquid crystal display device whose
`
`
`
`
`
`application to the structure of Japanese Patent Application
`No. 2006-109659 is under consideration.
`
`
`
`
`
`
`
`
`
`
`
`
`
`[0017]
`In FIG. 23 and FIG. 24, reference numerals 15, 16
`
`
`
`
`
`
`
`and 17 denote inter-layer insulating films; reference sign CT
`
`
`
`
`
`
`denotes a counter electrode; DD and DD1, electrodes func-
`
`
`
`
`
`
`
`tioning as the drain electrodes of thin-film transistors (active
`
`
`
`
`
`
`
`elements); PIX, a pixel electrode; RAL, a reflective elec-
`
`
`
`
`
`
`
`trode; and CH2, CH3 and CH4, contact holes.
`
`
`
`
`
`
`
`[0018] The transflective liquid crystal display device
`
`
`
`
`
`
`described in Japanese Patent Application No. 2006-109659,
`
`
`
`
`
`
`
`
`
`
`as shown in FIG. 23, has a structure in which the pixel
`
`
`
`
`
`
`
`
`electrode (PIX)
`is brought
`into direct contact with the
`
`
`
`
`
`
`
`electrode (DD) of a thin-film transistor via a contact hole
`
`
`
`
`
`
`
`CH3. This structure is realized by forming the inter-layer
`
`
`
`
`
`
`
`
`
`insulating film 17 inside the contact hole CH2 of the
`
`
`
`
`
`
`
`
`inter-layer insulating film 16 as well, boring a hole in this
`
`
`
`
`
`
`
`
`
`inter-layer insulating film 17 and utilizing its pattern to
`
`
`
`
`
`
`
`
`machine the inter-layer insulating film 15 underneath and
`
`
`
`
`
`
`thereby to bore the contact hole CH3.
`
`
`
`
`
`
`
`
`[0019] However, when boring the contact hole CH3, the
`
`
`
`
`
`
`
`difference in film quality between the inter-layer insulating
`
`
`
`
`
`
`
`
`
`
`film 15 and the inter-layer insulating film 17 may invite
`
`
`
`
`
`
`
`
`some trouble in machining them together, which would
`
`
`
`
`
`
`result in faulty electrical connection of the pixel electrode
`
`
`
`
`
`
`(PIX) to the electrode (DD) of the thin-film transistor.
`
`
`
`
`
`
`
`
`[0020]
`In view of this problem,
`the present
`inventors
`
`
`
`
`
`
`examined the possibility of machining the inter-layer insu-
`
`
`
`
`
`
`
`lating film 15 before machining the inter-layer insulating
`
`
`
`
`
`
`
`
`
`film 17. In this case, however, the electrode (DD) of the
`
`
`
`
`
`
`Page 24 of 34
`
`
`
`
`
`US 2008/0007679 A1
`
`
`
`Jan. 10, 2008
`
`
`
`thin-film transistor was dissolved when the reflective elec-
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`trode (RAL) was patterned, resulting again in faulty elec-
`
`
`
`
`
`
`
`trical connection of the pixel electrode (PIX) to the electrode
`
`
`
`
`
`
`
`(DD) of the thin-film transistor. This faulty connection
`
`
`
`
`
`
`
`
`invites a fall
`in the manufacturing yield of transflective
`
`
`
`
`liquid crystal display devices.
`
`
`
`
`
`
`
`
`
`[0021]
`In the peripheral circuit part, controlling the poten-
`
`
`
`
`
`
`
`
`
`tial to be supplied to the counter electrode (CT) with a
`
`
`
`
`
`
`thin-film transistor requires electrical connection between
`
`
`
`
`
`
`
`
`the electrode (DDl) of the thin-film transistor and the
`
`
`
`
`
`
`
`counter electrode (CT). Where the fabricating process
`
`
`
`
`
`
`
`
`
`described with reference to FIG. 23 is to be used,
`it is
`
`
`
`
`
`
`necessary to electrically connect the electrode (DDl) of the
`
`
`
`
`
`
`
`thin-film transistor and the counter electrode (CT) by using
`
`
`
`
`
`
`
`
`
`
`the top layer ITO film 20 (machined at the same step as the
`
`
`
`
`
`
`
`
`
`pixel electrode (PIX)) as shown in FIG. 24, and the increase
`
`
`
`
`
`
`
`
`in connection resistance due to the high chain resistance of
`
`
`
`
`
`
`
`the ITO poses a problem. An increased connection resistance
`
`
`
`
`
`
`
`
`gives rise to fluctuations in the driving voltage applied to the
`
`
`
`
`
`
`
`counter electrode (CT), which presumably invites deterio-
`
`
`
`ration in display quality.
`
`
`
`
`
`
`
`[0022] An object of the present invention is to provide a
`
`
`
`
`
`
`
`
`technique which enables the manufacturing yield of trans-
`
`
`
`
`
`
`flective liquid crystal display devices to be enhanced.
`
`
`
`
`
`
`
`
`[0023] Another object of the invention is to provide a
`
`
`
`
`
`
`
`technique which enables the display quality of transflective
`
`
`
`
`
`liquid crystal display devices to be improved.
`
`
`
`
`
`
`
`
`
`[0024] These and other objects and novel features of the
`
`
`
`
`
`
`
`
`invention will become more apparent from the description in
`
`
`
`
`
`
`
`
`this specification when taken into conjunction with the
`
`
`accompanying drawings.
`
`
`
`
`
`[0025] A brief summary of typical aspects of the invention
`
`
`
`
`
`
`disclosed in the present application is given below.
`
`
`
`
`
`
`
`(1) A transflective liquid crystal display device
`[0026]
`
`
`
`
`
`
`
`
`includes a liquid crystal display panel having a pair of
`
`
`
`
`
`
`
`
`
`substrates and a liquid crystal layer held between the pair of
`
`
`
`
`
`
`
`
`substrates, the liquid crystal display panel having a plurality
`
`
`
`
`
`
`
`
`of subpixels each having a transmissive part and a reflective
`
`
`
`
`
`
`
`
`
`
`part, wherein one of the pair of substrates has: an active
`
`
`
`
`
`
`
`
`element; a first insulating film disposed in a higher layer than
`
`
`
`
`
`
`
`
`the electrode of the active element and having a first contact
`
`
`
`
`
`
`
`
`hole; a counter electrode disposed in a higher layer than the
`
`
`
`
`
`
`
`first insulating film; a reflective electrode disposed in the
`
`
`
`
`
`
`
`
`reflective part in a higher layer than the counter electrode; a
`
`
`
`
`
`
`
`
`second insulating film disposed in a higher layer than the
`
`
`
`
`
`
`
`
`counter electrode and the reflective electrode and having a
`
`
`
`
`
`
`
`second contact hole; a pixel electrode disposed in a higher
`
`
`
`
`
`
`
`
`layer than the second insulating film; and an electroconduc-
`
`
`
`
`
`
`
`
`
`tor formed in the first contact hole and electrically connected
`
`
`
`
`
`
`
`
`
`to the electrode of the active element, and the pixel electrode
`
`
`
`
`
`
`
`is electrically connected to the electroconductor via the
`second contact hole.
`
`
`
`
`
`
`
`
`
`
`(2) In the configuration described in (1) above, the
`[0027]
`
`
`
`
`
`
`electroconductor is disposed inside and outside the first
`contact hole all over.
`
`
`
`
`
`
`
`
`
`
`
`
`
`(3) In the configuration described in (1) or (2)
`[0028]
`
`
`
`
`
`
`
`
`
`above, the one substrate has a third insulating film disposed
`
`
`
`
`
`
`
`
`
`in a higher layer than the electrode of the active element and
`
`
`
`
`
`
`
`
`
`
`in a lower layer than the first
`insulating film;
`the third
`
`
`
`
`
`
`
`
`
`insulating film has a third contact hole; and the electrocon-
`
`
`
`
`
`
`ductor is electrically connected to the electrode of the active
`element via the first and third contact holes.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`(4) In the configuration described in either one of
`[0029]
`
`
`
`
`
`
`
`
`(1) to (3) above, the electroconductor is formed at the same
`
`
`
`
`
`
`
`
`step as the counter electrode and electrically separated from
`the counter electrode.
`
`
`
`
`
`
`
`
`
`
`[0030]
`(5) In the configuration described in either one of
`
`
`
`
`
`
`
`
`(1) to (4) above, the electrode of the active element contains
`in the surface thereof 1% or more of the material of the
`
`
`
`
`
`
`
`
`
`reflective electrode.
`
`
`
`
`
`
`
`
`
`(6) In the configuration described in either one of
`[0031]
`
`
`
`
`
`
`
`
`(1) to (5) above, the electrode of the active element is formed
`
`
`
`
`
`
`
`
`
`
`of a material that is etched with the etchant or etching gas for
`the reflective electrode.
`
`
`
`
`
`
`
`
`
`
`[0032]
`(7) In the configuration described in either one of
`
`
`
`
`
`
`
`
`(1) to (6) above, the pixel electrode is arranged superposed
`
`
`
`
`
`
`
`
`
`over the counter electrode, and the pixel electrode,
`the
`
`
`
`
`
`
`
`
`second insulating film and the counter electrode together
`
`
`
`constitute a holding capacitance.
`
`
`
`
`
`
`
`(8) In the configuration described in either one of
`[0033]
`
`
`
`
`
`
`
`
`
`(1) to (7) above, each of the plurality of subpixels has the
`
`
`
`
`
`
`
`
`pixel electrode shared between the transmissive part and the
`
`
`
`
`
`
`
`
`
`reflective part and the counter electrodes independent for the
`
`
`
`
`
`
`
`
`
`transmissive part and the reflective part; and the driving
`
`
`
`
`
`
`
`
`voltages applied to the counter electrodes differ between the
`
`
`
`
`
`
`transmissive part and the reflective part.
`
`
`
`
`
`
`
`(9) In the configuration described in either one of
`[0034]
`
`
`
`
`
`
`
`
`
`(1) to (7) above, the reflective part is provided with a phase
`
`
`differential plate.
`
`
`
`
`
`
`
`(10) A transflective liquid crystal display device
`[0035]
`
`
`
`
`
`
`
`
`includes a liquid crystal display panel having a pair of
`
`
`
`
`
`
`
`
`
`substrates and a liquid crystal layer held between the pair of
`
`
`
`
`
`
`
`
`substrates, the liquid crystal display panel having a plurality
`
`
`
`
`
`
`
`
`of subpixels each having a transmissive part and a reflective
`
`
`
`
`
`
`
`
`
`
`part, wherein one of the pair of substrates has: an active
`
`
`
`
`
`
`
`
`element; a first insulating film disposed in a higher layer than
`
`
`
`
`
`
`
`
`the electrode of the active element and having a first contact
`
`
`
`
`
`
`
`
`hole; a common electrode in a higher layer than the first
`
`
`
`
`
`
`
`insulating film; a reflective electrode disposed in the reflec-
`
`
`
`
`
`
`
`
`tive part in a higher layer than the common electrode; a
`
`
`
`
`
`
`
`
`second insulating film disposed in a higher layer than the
`
`
`
`
`
`
`
`
`common electrode and the reflective electrode and having a
`
`
`
`
`
`
`
`second contact hole; a pixel electrode disposed in a higher
`
`
`
`
`
`
`
`
`layer than the second insulating film; and an electroconduc-
`
`
`
`
`
`
`
`
`
`tor forrned in the first contact hole and electrically connected
`
`
`
`
`
`
`
`
`
`to the electrode of the active element, the pixel electrode
`
`
`
`
`
`
`
`being electrically connected to the electroconductor via the
`second contact hole.
`
`
`
`
`
`
`
`
`
`(11) In the configuration described in (10) above,
`[0036]
`
`
`
`
`
`
`
`the electroconductor is disposed inside and outside the first
`contact hole all over.
`
`
`
`
`
`
`
`
`
`
`(12) In the configuration described in (10) or (11)
`[0037]
`
`
`
`
`
`
`
`
`above, the one substrate has a third insulating film disposed
`
`
`
`
`
`
`
`
`in a higher layer than the electrode of the active element and
`
`
`
`
`
`
`
`
`
`in a lower layer than the first
`insulating film;
`the third
`
`
`
`
`
`
`
`
`insulating film has a third contact hole; and the electrocon-
`
`
`
`
`
`ductor is electrically connected to the electrode of the active
`element via the first and third contact holes.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`(13) In the configuration described in either one of
`[0038]
`
`
`
`
`
`
`
`(10) to (12) above, the electroconductor is formed at the
`
`
`
`
`
`
`
`
`
`same step as the common electrode and electrically sepa-
`rated from the common electrode.
`
`
`
`
`
`
`
`
`
`
`
`
`[0039]
`(14) In the configuration described in either one of
`
`
`
`
`
`
`
`
`
`
`(10) to (13) above,
`the electrode of the active element
`contains in the surface thereof 1% or more of the material of
`
`
`
`
`
`
`the reflective electrode.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`Page 25 of 34
`
`Page 25 of 34
`
`
`
`
`
`US 2008/0007679 A1
`
`
`
`Jan. 10, 2008
`
`
`
`
`
`
`
`
`
`
`(15) In the configuration described in either one of
`[0040]
`
`
`
`
`
`
`
`
`(10) to (14) above, the electrode of the active element is
`formed of a material that is etched with the etchant or
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`etching gas for the reflective electrode.
`
`
`
`
`
`
`
`(16) In the configuration described in either one of
`[0041]
`
`
`
`
`
`
`
`
`(10) to (15) above, the pixel electrode is arranged super-
`
`
`
`
`
`
`
`
`
`posed over the common electrode, and the pixel electrode,
`
`
`
`
`
`
`
`
`the second insulating film and the common electrode
`
`
`
`
`together constitute a holding capacitance.
`
`
`
`
`
`
`
`(17) In the configuration described in either one of
`[0042]
`
`
`
`
`
`
`
`
`(10) to (16) above, the other of the pair of substrates has a
`counter electrode.
`
`
`
`
`
`
`
`
`
`(18) A transflective liquid crystal display device
`[0043]
`
`
`
`
`
`
`
`
`includes a liquid crystal display panel having a pair of
`
`
`
`
`
`
`
`
`
`substrates and a liquid crystal layer held between the pair of
`
`
`
`
`
`
`
`
`substrates, the liquid crystal display panel having a plurality
`
`
`
`
`
`
`
`
`of subpixels each having a transmissive part and a reflective
`
`
`
`
`
`
`
`
`
`
`part, wherein one of the pair of substrates has: an active
`
`
`
`
`
`
`
`element which supplies a driving potential to a counter
`
`
`
`
`
`
`
`electrode; a first insulating film disposed in a higher layer
`
`
`
`
`
`
`
`
`than the electrode of the active element and having a first
`
`
`
`
`
`
`
`
`contact hole; and the counter electrode disposed in a higher
`
`
`
`
`
`
`
`
`
`layer than the first insulating film,
`the counter electrode
`
`
`
`
`
`
`
`being electrically connected to the electrode of the active
`element via the first contact hole.
`
`
`
`
`
`
`
`
`
`
`
`
`
`(19) In the configuration described in (18) above,
`[0044]
`
`
`
`
`
`
`
`
`the subpixel has a reflective electrode in the reflective part;
`
`
`
`
`
`
`
`
`
`and a metal film formed at the same step as the reflective
`
`
`
`
`
`
`electrode is electrically connected to the counter electrode
`inside and outside the first contact hole all over.
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`[0045] Effects provided according to typical aspects of the
`
`
`
`
`
`
`
`
`invention disclosed in the present application are stated
`below.
`
`
`
`
`
`
`
`
`[0046] According to the invention, it is made possible to
`
`
`
`
`
`achieve improvement of the display quality of transflective
`
`
`
`
`
`
`
`
`liquid crystal display devices while enhancing the manufac-
`
`
`
`
`
`
`
`turing yield of transflective liquid crystal display devices.
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`
`
`
`
`
`
`
`
`
`
`[0047] These and other features, objects and advantages of
`
`
`
`
`
`
`
`
`
`the present invention will become more apparent from the
`
`
`
`
`
`
`
`following description when taken in conjunction with the
`
`
`
`accompanying drawings wherein:
`
`
`
`
`
`
`FIG. 1A shows a plan of the electrode structure of
`[0048]
`
`
`
`
`
`
`
`the subpixel in a transflective liquid crystal display device,
`
`
`
`
`
`which is a first embodiment of the present invention;
`
`
`
`
`
`
`
`[0049]
`FIG. 1B shows only the pixel electrode, counter
`
`
`
`
`
`
`
`
`electrode and reflective electrode taken out of FIG. 1A;
`
`
`
`
`
`
`
`FIG. 2 shows the essential part of a sectional
`[0050]
`
`
`
`
`
`
`structure along line A-A' in FIG. 1A;
`
`
`
`
`
`
`
`FIG. 3 shows the essential part of a sectional
`[0051]
`
`
`
`
`
`
`structure along line B-B' in FIG. 1A;
`
`
`
`
`
`
`
`FIG. 4 shows the essential part of a sectional
`[0052]
`
`
`
`
`
`
`structure along line C-C' in FIG. 1A;
`
`
`
`
`
`
`
`
`
`FIG. 5 shows the essential parts of the sectional
`[0053]
`
`
`
`
`
`
`
`structures of the transmissive part and the reflective part in
`
`
`
`
`
`
`
`
`
`the transflective liquid crystal display device of the first
`
`embodiment;
`
`
`
`
`
`
`FIG. 6A shows an essential part of the manufac-
`[0054]
`
`
`
`
`
`
`
`
`turing process of the transflective liquid crystal display
`
`
`
`
`
`
`
`device which is the first embodiment of the invention;
`
`
`
`
`
`
`
`FIG. 6B shows the essential part following FIG. 6A
`[0055]
`
`
`
`
`
`
`
`
`of the manufacturing process of the transflective liquid
`
`
`
`crystal display device;
`
`
`
`
`
`
`
`
`
`
`
`Page 26 of 34
`
`
`
`
`
`
`
`
`
`
`FIG. 6C shows the essential part following FIG. 6B
`[0056]
`
`
`
`
`
`
`
`of the manufacturing process of the transflective liquid
`
`
`
`crystal display device;
`
`
`
`
`
`
`
`FIG. 6D shows the essential part following FIG. 6C
`[0057]
`
`
`
`
`
`
`
`
`of the manufacturing process of the transflective liquid
`
`
`
`crystal display device;
`
`
`
`
`
`
`
`FIG. 6E shows the essential part following FIG. 6D
`[0058]
`
`
`
`
`
`
`
`
`of the manufacturing process of the transflective liquid
`
`
`
`crystal display device;
`
`
`
`
`
`
`
`
`FIG. 6F shows the essential part following FIG. 6E
`[0059]
`
`
`
`
`
`
`
`
`of the manufacturing process of the transflective liquid
`
`
`
`crystal display device;
`
`
`
`
`
`
`
`
`FIG. 7 shows an equivalent circuit to the pixel part
`[0060]
`
`
`
`
`
`
`
`
`
`of liquid crystal display panel of the transflective liquid
`
`
`
`
`
`
`
`crystal display device which is the first embodiment of the
`
`invention;
`
`
`
`
`
`
`
`FIG. 8 illustrates the voltage waveforms of the
`[0061]
`
`
`
`
`
`subpixel ((PXL) (n, k)) as shown in FIG. 7;
`
`
`
`
`
`
`FIG. 9 shows an equivalent circuit to the peripheral
`[0062]
`
`
`
`
`
`
`
`
`circuit part of the liquid crystal display panel in the trans-
`
`
`
`
`
`
`flective liquid crystal display device of the first embodiment;
`
`
`
`
`
`
`
`
`FIG. 10 shows the essential part of the sectional
`[0063]
`
`
`
`
`
`structure of the connecting part surrounded by broken lines
`
`
`in FIG. 9;
`
`
`
`
`
`
`[0064]
`FIG. 11 shows a plan of the electrode structure of
`
`
`
`
`
`
`
`
`the subpixel in the transflective liquid crystal display device,
`
`
`
`
`
`
`which is the first embodiment of the invention;
`
`
`
`
`
`
`
`[0065]
`FIG. 12 shows the reference voltages to be applied
`
`
`
`
`
`
`
`
`
`
`to the counter electrode of the transmissive part and the
`
`
`
`
`
`
`
`counter electrode of the reflective part in the transflective
`
`
`
`
`
`
`liquid crystal display device of the first embodiment