JP2004258245A - Electro-optic device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce difference in the resistance of a conducting wire due to difference in inter-wiring distances between a plurality of conducting wires and to simplify designing and manufacturing of circuits. <P>SOLUTION: The widths of the conducting wires are changed according to the inter-wiring distances and the widths of the conducting wires are made equal in a plurality of wires of about 10 wires adjacent to each other and are changed stepwise. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２５】
断面積Ｓは配線の厚さｔと幅ｄの積であるから、抵抗値Ｒはまた数３で表すことができる。
【００２６】
【数３】

【００２７】
つまり数３より、引き回し抵抗値Ｒは配線の距離ｌに比例し、幅ｄに反比例することがわかる。
【００２８】
本実施形態の構造を有する電気光学装置においては、引き回し距離は画面上部ほど長くなり、画面下端と上端とでは、当該電気光学装置のサイズや形状により異なるが、およそ５〜３０倍の差異が生じる。従って従来のように配線の幅が一定であれば、画面上部ほど抵抗の増大、すなわち画質の低下が起こり、更には画面の上下で画質が不均一となる問題も生じる。
しかし、本実施形態のように配線の幅ｄを異ならせることにより、上述の問題を緩和させることが可能である。既に述べたように引き回し抵抗値Ｒは配線の幅ｄに反比例するから、配線の幅をある定数倍にすれば、引き回し抵抗値Ｒは前記定数の逆数倍となる。
【００２９】
配線距離の短い導線は細く、配線距離の長い導線は太くし、全ての配線の引き回し抵抗が一定になることが望ましいのだが、太くするにはサイズおよび形状の制約があり、また細くするにはスパッタリング工程での装置の性能による制約があり、実際には配線の幅は相応の値までに制限される。また、導線の幅の推移についても、連続的に幅を変化させるのが理想的であるが、コスト等の問題を考慮すると、複数の導線をまとめてグループ化し、同一グループの導線の幅を同一にし、グループ毎に導線の幅を段階的に変化させるようにしたほうが製造には容易である。
本実施形態の電気光学装置においては、導線Ｙ_１が１０μｍであるのに対して導線Ｙ_２ｎは３μｍであり、導線の幅を一定にした場合と比較して画面上下の抵抗差は１／３程度に抑えることが可能となる。
【００３０】
最後に、以上説明した電気光学装置を搭載した電子機器について説明する。
図６は電気光学装置１００を表示部とする携帯電話端末５０の外観図である。同図において携帯電話端末５０は、複数の操作ボタン５１の他、受話口５２，送話口５３と共に、電話番号等の各種情報を表示する表示部として上記電気光学装置１００を具備している。
また、携帯電話端末５０以外にも、上記電気光学装置１００は、コンピュータ、プロジェクタ、デジタルスチルカメラ、ムービーカメラ、車載機器、複写機、オーディオ機器等の各種電子機器の表示部として用いることも可能である。
【００３１】
＜変形例＞
なお、上述の実施形態においては、便宜上アクティブマトリクス型のＴＦＤ液晶を用いた電気光学装置を説明に用いたが、本発明は上述の装置に限定されるものではなく、その他種々の電気光学装置、例えばＴＦＴ（Ｔｈｉｎ Ｆｉｌｍ Ｔｒａｎｓｉｓｔｏｒ）液晶等の液晶表示装置、有機エレクトロ・ルミネセンス表示装置、プラズマディスプレイ表示装置等にも適用可能である。また、上述の装置以外の構成からなるアクティブマトリクス型のＴＦＤ液晶を用いた電気光学装置への適用も勿論可能である。
また、上述の実施形態においてはＲＧＢ３色のサブ画素から構成されるカラー表示の液晶表示装置であったが、引き回し抵抗の増大による画質の低下は単色表示であっても同様に起こる事象であるから、本発明は単色表示の液晶表示装置においても適用可能である。
【図面の簡単な説明】
【図１】本発明の一実施形態である電気光学装置の斜視図である。
【図２】同実施形態における電気光学装置の電気的構成を示すブロック図である。
【図３】同実施形態における電気光学装置の平面図である。
【図４】図３におけるＡ−Ａ’線に従った断面図である。
【図５】図３におけるＢの部分の拡大図である。
【図６】本発明に係る電気光学装置を表示部として搭載した電子機器の一例を示す図である。
【符号の説明】
１００…電気光学装置本体、１…パネル、２…データ線、３…走査線、４…画素、２０…素子基板、３０…対向基板、４０…シール材、４２…導電粒子、４３…液晶、５０…携帯電話端末。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electro-optical device such as a liquid crystal display device, an organic electroluminescence display device, and a plasma display device.
[0002]
[Prior art]
2. Description of the Related Art Display devices such as liquid crystal display devices, organic electroluminescence display devices, and plasma display devices utilizing electro-optical materials whose optical properties change upon application of a voltage have been put to practical use. These displays have electrodes for applying a voltage to the electro-optical material and a drive circuit, which are connected by conductors.
[0003]
When a plurality of the conductors are connected to the drive circuit, each of the conductors may have a different length. For example, in a liquid crystal display device used for a mobile phone terminal, a non-display area (a so-called picture frame) for arranging a lead wire and a driving circuit on two sides opposite to each other with respect to a screen display in accordance with the miniaturization of the terminal. Area) is required to be narrow, so the drive circuit is placed at the bottom of the screen, and the leads from the scanning electrodes from the top to the bottom of the screen are integrated into the drive circuit along the left and right sides of the screen in the frame area Some have a structure (hereinafter, referred to as a “routing structure”), and in such a case, the difference in the conductor distance is remarkable.
[0004]
If the conditions such as the material and cross-sectional area of the conductor are the same, the resistance of the conductor is proportional to its length. That is, if the signal from the drive circuit is an equal voltage, the longer the lead-out distance, the greater the resistance is affected by the resistance, and a larger voltage drop occurs. As a result, the input signal waveform, which is a pulse wave, is attenuated and dull before reaching the electrodes, resulting in a deterioration in image quality.
[0005]
There are several ways to solve this problem. For example, a method of using a low-resistance material for a conductive wire having a long wiring distance (for example, see Patent Literature 1), a method of adding a correction signal that compensates for attenuation of an input signal, and the like can be considered. However, the use of different materials for the conductors on the same substrate is inconvenient in terms of manufacturing cost, and the input of the correction signal has a large difference in voltage drop between the top and bottom of the screen, so the effect is expected. Can not.
[0006]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2002-297057
[Problems to be solved by the invention]
The present invention has been made under such a background, and an object of the present invention is to provide an electro-optical device that reduces the influence of resistance due to the routing of a conductive wire.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides an electro-optic material, a plurality of electrodes for applying a voltage to the electro-optic material, and a drive circuit for supplying a drive signal to each of the electrodes from a plurality of output terminals. A plurality of conductors respectively connecting the respective electrodes and the respective output terminals of the drive circuit, wherein the plurality of conductors have, at least in part, a cross section having a longer length than a shorter length. It is characterized by being large.
[0009]
By increasing the cross-sectional area of the conductor as the distance of the conductor increases, attenuation of the input signal to the electrode due to the difference in the distance between the drive circuit and the electrode can be reduced, and the cross-sectional area of the conductor can be reduced. Is changed stepwise rather than continuously, thereby making it possible to design and manufacture the circuit simply and inexpensively.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a case where the present invention is applied to an electro-optical device that is an active matrix type including a TFD (Thin Film Diode) element as a switching element and uses liquid crystal as an electro-optical material will be described with reference to the drawings. An embodiment of the present invention will be described.
In all the drawings, the dimensions of the components of the device are appropriately changed or the continuous structure is not shown in order to easily understand the configuration of the device.
[0011]
<Configuration of the embodiment>
FIG. 1 is a perspective view of the electro-optical device 100 according to the present invention as viewed from the rear side, that is, from the side where no image is displayed, and FIG. 2 is a block diagram showing the electrical configuration thereof. However, in FIG. 1, the back side and the observation side may be reversed. As shown in these two figures, a plurality of scanning lines (common electrodes) 2 are formed on the panel 1 so as to extend in the row (X) direction, while a plurality of data lines (segment electrodes) 3 are provided. It is formed to extend in the column (Y) direction. Each intersections of the scanning lines 2 and the data line 3 sub-pixels 4 _R consisting TFD element 5 and the liquid crystal display element _6, 4 _G, 4 _B are formed. The sub-pixels 4 _R , 4 _G , and 4 _B are pixels for displaying red (R), green (G), and blue (B), respectively, and the pixel 4 is formed by regularly arranging them.
[0012]
Each wire _X 1 a plurality of data lines _3, X 2, ..., are connected to the X driver 7 which is the driver circuit via the _{X m,} and a plurality of scanning lines 2 each conductor _{Y 1, Y 3, Y 5} , _{..., Y 2n-1,} i.e. conductor _{Y 2n-1} of the odd-numbered counted from the top are connected to the Y driver 8a, whereas conductors _{Y 2, Y 4, Y 6} , ..., Y 2n, i.e. counted from the top even number The second conducting wire _Y2n is connected to the Y driver 8b. In the present embodiment, the values of m and n in X _m and Y _2n are such that m is about 720 and n is about 160. When it is not necessary to particularly distinguish the Y driver 8a and the Y driver 8b, the Y driver 8 is simply referred to as a Y driver 8 below. Also, conductors _{X 1,} X 2, ..., _{X m} and conductors _{Y 1,} Y 2, _..., the even _{Y 2n,} respectively denoted as wire X and conductor Y when it is not needed to distinguish.
These conductive wires X and Y are formed by sputtering Cr (chromium) on a substrate, and the film pressure is constant.
The control circuit 9 supplies various control signals to the X driver 7 and the Y driver 8, and the voltage forming circuit 10 supplies a data voltage and a scanning voltage.
[0013]
As shown in FIG. 1, the electro-optical device 100 according to the present invention includes a Y driver 8 on each of the left and right sides of the X driver 7 and is symmetrical. Along with this, the plurality of scanning lines 2 connected to the Y driver 8 have a structure in which they are routed on the left and right frame regions of the panel 1 as shown in FIG. By adopting such a structure, it is possible to reduce the non-display area on the left and right of the electro-optical device 100, that is, the so-called frame region, and the electro-optical device 100 is required to have a narrow frame region and a symmetrical shape. It is effective for application to.
[0014]
Next, the configuration of the panel 1 will be described.
FIG. 3 is a plan view seen from the front side of the observer. FIG. 4 is a sectional view taken along the line AA 'in FIG. In these two figures, a pixel electrode 21, a peripheral light-shielding layer 22, an alignment film 23, and the like are formed on an element substrate 20, which is a first substrate, and a reflective layer is formed on an opposing substrate 30, which is a second substrate. 31, a color filter 32, a light-shielding layer 33, an overcoat layer 34, an alignment film 35 and the like are formed, and a liquid crystal 43 is sealed between the two substrates.
[0015]
As shown in these figures, the electro-optical device 100 includes an element substrate 20 and an opposing substrate 30 which are opposed to each other, which are bonded together by a sealing material 40, and a liquid crystal is formed in a region surrounded by both substrates and the sealing material 40. 43 is enclosed. The sealing material 40 is formed in a substantially rectangular frame shape along the outer periphery of the counter substrate 30. An opening for enclosing the liquid crystal is formed in a part of the sealing material 40. After the liquid crystal is sealed through the opening, the sealing material 41 is used for sealing.
[0016]
A large number of conductive particles 42 (conductive members) having conductivity are dispersed in the sealing material 40. These conductive particles are, for example, plastic particles or the like subjected to metal plating, and have a function of electrically connecting wirings formed on each of the element substrate 20 and the counter substrate 30 and a spacer for maintaining a constant cell gap between the two substrates. It also has the function of
[0017]
As shown in FIG. 3, the distal end portions of the plurality of conductive wires Y form a plurality of conducting portions Ya. Similarly, a leading end of the scanning line 2 forms a conducting portion 2a. The conducting portions Ya and 2a are conducted through the conductive particles 42 in the sealing material 40, so that the scanning line 2 is conducted to the Y driver 8.
[0018]
Actually, a polarizing plate for polarizing incident light, a retardation plate for compensating for interference color, and the like are attached to the outer surfaces of the element substrate 20 and the counter substrate 30. Since it has no direct relation to the invention, its illustration and description are omitted.
By adopting the above-described structure of the panel 1, it is possible to mount the IC chip or the like, which had to be conventionally performed on both substrates, on only one of the element substrates. It is possible to simplify and improve the manufacturing efficiency.
[0019]
Next, the structure of the conductor portion will be described.
FIG. 5 is an enlarged view of a conductive wire portion B in FIG. As shown in the figure, the conductors Y ₁ , Y ₃ , Y ₅ ,..., Y _2n-1 in the present embodiment are characterized in that their line widths are not constant. In the figure, the group _{G 1,} G 2 consisting of a plurality of wires Y, ..., the line width of the individual conductors contained within the _{G k} are equal, the group _{G 1,} G 2, ..., the line width of the conductor of _{G k} Are w ₁ , w ₂ ,..., W _k , respectively.
[0020]
(Equation 1)
w ₁ > w ₂ >...> w _k
[0021]
The line width of these wires are 10μm approximately in conductors Y ₁ to be connected to the electrode of the LCD screen upper end, the lower part of the screen, i.e. the line width as it approaches the driving circuit stepwise narrows, the electrodes of the liquid crystal screen bottom The length of the connecting wire Y _2n-1 is about 3 μm. That is, the line width is gradually increased as the length of the lead wires becomes longer. The distance between adjacent conductors, that is, the width of the insulating portion is constant, and its value is about 3 μm.
In the present embodiment, the line width of the conductor is changed about every ten lines. However, the number of conductors having the same line width may be larger or smaller.
Although the structure described above is for the conductor connected to the Y driver 8a, the same applies to the conductor connected to the Y driver 8b.
[0022]
<Operation of Embodiment>
The operation of the electro-optical device having the above configuration will be described below.
The voltage supplied from the voltage forming circuit 10 is applied to the pixels 4 on the panel 1 through a driving circuit and a conductor, and an image is formed on a display area. At this time, the input signal waveform output from the voltage forming circuit 10 is attenuated by the electric resistance before reaching the pixel 4, and a signal waveform different from the original waveform is applied to the pixel 4. Therefore, there is a problem that the color of the pixel 4 displayed on the screen is different from the expected color.
[0023]
The above-mentioned voltage drop is mainly caused by the output resistance from the drive circuit, the wiring resistance due to the wiring wiring, and the electrode resistance on the electrodes, of which the output resistance and the electrode resistance are values specific to the device and are always constant. .
The routing resistance depends on the routing distance of the wiring. Assuming that the cross-sectional area of the wiring is S, the distance is 1 and the specific resistance is ρ, the resistance value R due to the routing resistance is expressed by Equation 2.
[0024]
(Equation 2)

[0025]
Since the cross-sectional area S is the product of the thickness t and the width d of the wiring, the resistance value R can be expressed by the following equation (3).
[0026]
[Equation 3]

[0027]
That is, according to Equation 3, it is understood that the routing resistance value R is proportional to the distance l of the wiring and inversely proportional to the width d.
[0028]
In the electro-optical device having the structure of the present embodiment, the routing distance becomes longer toward the upper part of the screen, and a difference of about 5 to 30 times occurs between the lower end and the upper end of the screen depending on the size and shape of the electro-optical device. . Therefore, if the width of the wiring is constant as in the related art, there is a problem that the resistance increases, that is, the image quality deteriorates toward the upper part of the screen, and further, the image quality becomes uneven at the top and bottom of the screen.
However, by changing the width d of the wiring as in the present embodiment, the above-described problem can be reduced. As described above, the routing resistance value R is inversely proportional to the wiring width d. Therefore, if the wiring width is multiplied by a certain constant, the routing resistance value R becomes the reciprocal of the constant.
[0029]
It is desirable that the conductors with short wiring distances be thin, and the conductors with long wiring distances be thick, and that the routing resistance of all wiring be constant. Due to the performance of the apparatus in the sputtering process, the width of the wiring is actually limited to a corresponding value. Ideally, the width of conductors should also be changed continuously.However, considering the cost and other issues, multiple conductors are grouped together and the width of conductors in the same group is the same. It is easier to manufacture if the width of the conductive wire is changed stepwise for each group.
In the electro-optical device according to the present embodiment, the conductor Y ₁ is 10 μm, whereas the conductor Y _2n is 3 μm, and the resistance difference between the upper and lower parts of the screen is １ ／ as compared with the case where the width of the conductor is constant. It can be suppressed to the extent.
[0030]
Finally, an electronic device equipped with the above-described electro-optical device will be described.
FIG. 6 is an external view of a mobile phone terminal 50 having the electro-optical device 100 as a display unit. In the figure, a mobile phone terminal 50 includes the electro-optical device 100 as a display unit for displaying various information such as a telephone number, in addition to a plurality of operation buttons 51, an earpiece 52 and a mouthpiece 53.
In addition to the mobile phone terminal 50, the electro-optical device 100 can be used as a display unit of various electronic devices such as a computer, a projector, a digital still camera, a movie camera, a vehicle-mounted device, a copying machine, and an audio device. is there.
[0031]
<Modification>
In the above-described embodiment, the electro-optical device using the active matrix type TFD liquid crystal is used for convenience, but the present invention is not limited to the above-described device, and various other electro-optical devices, For example, the present invention can be applied to a liquid crystal display device such as a TFT (Thin Film Transistor) liquid crystal, an organic electroluminescence display device, a plasma display device, and the like. Further, it is of course possible to apply to an electro-optical device using an active matrix type TFD liquid crystal having a configuration other than the above-described device.
Further, in the above-described embodiment, the liquid crystal display device of the color display is composed of the RGB three-color sub-pixels. However, the deterioration of the image quality due to the increase of the drawing resistance is the same phenomenon even in the case of the single-color display. The present invention is also applicable to a monochromatic liquid crystal display device.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electro-optical device according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating an electrical configuration of the electro-optical device according to the embodiment.
FIG. 3 is a plan view of the electro-optical device according to the embodiment.
FIG. 4 is a sectional view taken along line AA ′ in FIG. 3;
FIG. 5 is an enlarged view of a portion B in FIG. 3;
FIG. 6 is a diagram illustrating an example of an electronic apparatus in which the electro-optical device according to the invention is mounted as a display unit.
[Explanation of symbols]
Reference Signs List 100 electro-optical device main body, 1 panel, 2 data lines, 3 scanning lines, 4 pixels, 20 element substrates, 30 counter substrates, 40 sealing materials, 42 conductive particles, 43 liquid crystals, 50 ... mobile phone terminals.

Claims (4)

An electro-optic material,
A plurality of electrodes for applying a voltage to the electro-optical material,
A drive circuit for supplying a drive signal to each of the electrodes from a plurality of output terminals,
A plurality of conductors respectively connecting each of the electrodes and each output terminal of the drive circuit,
The electro-optical device according to claim 1, wherein at least a part of the plurality of conductors has a longer cross section than a longer one. An electro-optic material,
A first substrate and a second substrate that are arranged to face each other with the electro-optical material interposed therebetween;
A plurality of electrodes for applying a voltage to the electro-optical material and a first electrode group arranged on the first substrate;
A second electrode group that is a plurality of electrodes that apply a voltage to the electro-optical material and is disposed on the second substrate;
A conducting member for conducting each electrode of the first electrode group to the second substrate;
A drive circuit that supplies a drive signal to each of the first and second electrode groups from a plurality of output terminals, and is provided on the second substrate;
Each electrode of the first electrode group and each output terminal of the drive circuit are connected via the conductive member along the second substrate, and at least a portion having a longer length is shorter. An electro-optical device comprising: a conductor having a larger cross-sectional area than that of the electro-optical device. The plurality of conductors are divided into a plurality of groups in order of length, and the plurality of conductors have different cross-sectional areas for each group, and those belonging to a group including a longer conductor have a larger cross-sectional area. The electro-optical device according to claim 1, wherein: An electronic apparatus comprising the electro-optical device according to claim 1 as a display unit.

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