JP2010085813A - Electro-optical device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of electrical corrosion in a wet processing process, and achieve high quality display, in an electro-optical device. <P>SOLUTION: On a substrate (10), the electro-optical device includes: a pixel electrode (9) and first conductive layers (71, 91) including a first conductive material; a second conductive layer (92) including a second conductive material whose ionization tendency is different in comparison with the first conductive material; and a thin film transistor (500), in which a source (500a1) and a drain (500a3) are connected to the first conductive layer and the second conductive layer, and which relays and connects the first conductive layer with the second conductive layer by applying a voltage to a gate (500b). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technical field of an electro-optical device such as a liquid crystal device, and an electronic apparatus such as a liquid crystal projector including the electro-optical device.

  In this type of electro-optical device, a pixel electrode, a scanning line for selectively driving the pixel electrode, a data line, and a TFT (Thin Film Transistor) as a pixel switching element are provided on a substrate. Thus, the active matrix driving is possible. In addition, a storage capacitor may be provided between the TFT and the pixel electrode for the purpose of increasing the contrast. For example, Patent Document 1 discloses a technique for ensuring a high aperture ratio by configuring a storage capacitor from a pair of transparent electrodes facing each other with a capacitor insulating film interposed therebetween.

  Here, in the active matrix driving, the operation of the TFT is controlled by supplying a scanning signal to the scanning line, and an image signal is supplied to the data line at a timing when the TFT is turned on. Display is realized. Such an electro-optical device has a technical problem that display unevenness occurs due to push-down of an image signal potential written to the data line. Patent Document 2 discloses a technique of providing a capacitor or a capacitor that is electrically connected to a part of a data line as means for solving such a technical problem.

Japanese Patent Laid-Open No. 6-148684 Japanese Patent Laid-Open No. 2004-125887

  Here, when the various functional films formed on the substrate as described above are formed of conductive materials having different ionization tendency, for example, when forming various functional films by patterning, wet etching or photo In a wet processing step such as resist stripping, there is a technical problem that these materials having different ionization tendencies are exposed to the processing solution at the same time, thereby causing galvanic corrosion. For example, a capacitor electrode made of an ITO (Indium Tin Oxide) film disposed on the upper layer side of a substrate and a wiring made of aluminum are simultaneously exposed to a processing solution such as an etching solution or a resist stripping solution used in a wet processing step. As a result, aluminum atoms having a high ionization tendency are dissolved in the processing solution and corroded. As a result, an error or error occurs in the voltage value of an electric signal such as an image signal, and the quality of the display image is deteriorated.

  The present invention has been made in view of the above-described problems, for example, and an electro-optical device capable of performing high-quality display while preventing the occurrence of electrolytic corrosion in a wet treatment process, and such an electro-optical device. It is an object to provide an electronic device including the device.

  In order to solve the above-described problems, an electro-optical device according to an aspect of the invention includes a plurality of pixel electrodes arranged on a pixel region, the first conductive material on the substrate, and the same as the first conductive material. A first conductive layer comprising a material and constituting at least a part of a wiring, an electrode and an electronic element for performing an electro-optic operation in the pixel region, and a first ionization tendency different from that of the first conductive material. A second conductive layer comprising at least another part of the wiring, the electrode and the electronic element, and one of a source and a drain is formed of the first conductive layer and the second conductive layer. The other of the source and the drain is electrically connected to the other of the first conductive layer and the second conductive layer, and a voltage is applied to the gate. The first conductive layer and The serial second conductive layer and a thin film transistor for relay connection.

  According to the electro-optical device of the present invention, on the substrate, for example, wirings such as scanning lines and data lines and electronic elements such as pixel switching TFTs are insulated from each other via an insulating film as necessary. A circuit for driving the pixel electrode is configured by stacking, and an image electrode is formed on the upper layer side. In particular, the pixel electrode in the present invention is formed including a first conductive material, for example, a transparent material such as an ITO film. During the operation of the electro-optical device, an image signal is supplied to the pixel electrode through the data line, for example, at a timing corresponding to the on / off operation of the pixel switching TFT. This enables image display in a pixel area or a pixel array area (typically referred to as “image display area”) in which a plurality of pixel electrodes are arranged.

  The first conductive layer is at least part of a wiring, an electrode, and an electronic element for performing an electro-optical operation in the pixel region. For example, the first conductive layer may be configured as one of a pair of capacitive electrodes constituting an additional capacitor for achieving high contrast, or a shield layer that blocks an electric field generated between conductive layers having different potentials. Etc. may be configured. The first conductive layer is formed to include the same first conductive material as the pixel electrode. In this manner, by forming the pixel electrode and the first conductive layer with the same material, it is possible to reduce the types of processing liquids such as the etching liquid and the resist stripping liquid used in the wet processing process in the electro-optical device manufacturing stage. It is possible to reduce the cost. Further, if they are formed of the same conductive material, even if the pixel electrode and the first conductive layer are simultaneously exposed to an acid such as a stripping solution in the step of forming the pixel electrode and the first conductive layer, electric contact occurs. Thus, the pixel electrode and the first conductive layer are not corroded.

  The second conductive layer constitutes at least a part of another wiring, electrode, or electronic element for performing an electro-optical operation (for example, the above-described image display) different from the first conductive layer. For example, the second conductive layer can be configured as a constant potential line or the like for supplying a fixed potential to one of a pair of capacitor electrodes constituting the additional capacitor. The second conductive layer includes a second conductive material that has a different ionization tendency than the first conductive material. Therefore, if the first conductive layer and the second conductive layer are simultaneously exposed to a treatment liquid such as a stripping solution, as described above, the conductive material having a high ionization tendency is changed to the conductive material having a low ionization tendency. Electrons move, and constituent atoms of the conductive layer having a high ionization tendency are dissolved as ions into the treatment liquid, causing electrolytic corrosion and corroding the conductive layer. For example, when the first conductive layer is formed of a transparent electrode such as an ITO film and the second conductive layer is formed of a metal such as highly conductive aluminum, aluminum having a high ionization tendency is dissolved in the processing solution, The formed second conductive layer is corroded. Therefore, in the present invention, the electrolytic corrosion is prevented by interposing a transistor described below between the first conductive layer and the second conductive layer.

  The transistor is arranged so as to relay-connect between the first conductive layer and the second conductive layer when a voltage is applied to its gate. That is, one of the source and the drain is electrically connected to one of the first conductive layer and the second conductive layer, and the other of the source and the drain is connected to the other of the first conductive layer and the second conductive layer. Electrically connected. As described above, by disposing the transistor between the first conductive layer and the second conductive layer, it is possible to prevent the first conductive layer and the second conductive layer from being eroded in the manufacturing process of the electro-optical device. Of course, since the electro-optical device is not operating in the manufacturing stage, the transistor is always turned off, and the first conductive layer and the second conductive layer are kept electrically disconnected (that is, the conductive layer). And the capacitor electrodes are insulated). Therefore, even if the first conductive layer and the second conductive layer are exposed to the treatment liquid at the same time in the manufacturing process, there is no movement of electrons between them, and no electric corrosion occurs. On the other hand, when the electro-optical device is actually operated after the manufacturing process is completed, for example, the first conductive layer and the second conductive layer are always electrically connected by always turning on the transistor. Can be in a state. In other words, during the operation of the electro-optical device, the transistor functions as a part of the conductive wiring together with the first conductive layer and the second conductive layer. As described above, by providing the transistor, in the manufacturing process, the electro-optical device is actually completed while preventing the electric corrosion from occurring by electrically insulating the first conductive layer and the second conductive layer. In the operation, the first conductive layer and the second conductive layer can be electrically connected to function as if they were integrated wiring. Therefore, when the first conductive layer and the second conductive layer are electrically connected to each other and simultaneously exposed to the treatment liquid, the conductive layer is corroded (in other words, the conductive layer corrodes due to the battery effect or the battery action). ) Can be prevented.

  As described above, according to the electro-optical device of the present invention, it is possible to prevent the occurrence of electrolytic corrosion in the wet treatment process. As a result, a conductive layer made of a different conductive material can be formed with high quality, so that an electro-optical device capable of displaying a high-quality image without causing deterioration or error in an electric signal such as an image signal. Can be realized.

  In one aspect of the electro-optical device of the present invention, the pixel electrode and the first conductive layer are disposed to face each other via a capacitor insulating film, thereby forming a storage capacitor.

  According to this aspect, in the electro-optical device, the pixel electrode and the first conductive layer are used as a pair of capacitor electrodes, and the storage capacitor with the capacitor insulating film interposed therebetween is formed. For example, a storage capacitor connected to a pixel electrode to which an image signal is supplied can be formed by supplying a fixed potential to the first conductive layer formed on the lower layer side of the pixel electrode from a power supply line or the like. As a result, for example, the holding capacitance is added to the wiring capacitance of the wiring to which the image signal is applied, or the capacitance caused by the overlap with other wiring, so that the potential that the original image signal should have varies. That is, it is possible to suppress the push-down of the image signal potential written to the pixel electrode. As a result, it is possible to reduce or prevent the occurrence of display unevenness along, for example, the data line due to the push-down of the image signal potential written to the pixel electrode.

  In another aspect of the electro-optical device of the present invention, the first conductive material is ITO.

  According to this aspect, both the pixel electrode and the first conductive layer are made of ITO. Since ITO is a transparent conductive material, the transmittance of the electro-optical device is lowered by using it for the pixel electrode arranged for each pixel or the first conductive layer formed on the lower layer side of the pixel electrode. And good signal transmission can be realized. Therefore, by using ITO as the first conductive material, it is possible to realize an electro-optical device having high transmittance and capable of displaying a high-quality image.

  In addition, since ITO has a comparatively large resistance value compared with metal materials, such as aluminum, in this aspect, the 1st conductive layer formed with ITO should be formed as an element etc. for which high-speed operation is not required. Is preferred. For example, as described above, the capacitor electrode and the shield layer to which a fixed potential is applied may be formed of the first conductive material.

  In another aspect of the electro-optical device of the present invention, the second conductive layer constitutes an external connection terminal arranged in a peripheral region located around the pixel region.

  According to this aspect, the second conductive layer constituting at least a part of one wiring, electrode, or electronic element for performing the electro-optic operation is not in the image display region in which the electro-optic operation is performed, but in the peripheral region. It is formed as an external connection terminal. For this reason, the first conductive layer electrically connected to the second conductive layer via the transistor is mostly formed in the image display region, but a part thereof extends to the peripheral region. Therefore, the above-described transistor is also arranged in the peripheral region, and the source and drain are connected to the first conductive layer and the second conductive layer in the peripheral region.

  In another aspect of the electro-optical device of the present invention, a potential line for supplying a predetermined potential is provided on the substrate, and the gate is electrically connected to the potential line.

  According to this aspect, the gate of the transistor is electrically connected to a potential line that supplies a predetermined potential (for example, a constant potential). Therefore, the transistor can be turned off in the wet treatment step in the manufacturing process, and the transistor can be turned on when the electro-optical device is completed. That is, in the wet treatment process, the first potential is not supplied to the gate of the transistor and the transistor is turned off, so that the first conductive layer and the second conductive layer can be electrically disconnected, and the electrical During operation of the optical device, a predetermined potential is supplied to the gate of the transistor and the transistor is turned on, whereby the first conductive layer and the second conductive layer can be electrically connected. Therefore, the occurrence of electrolytic corrosion in the wet treatment process can be prevented.

  In another aspect of the electro-optical device of the present invention, the electro-optical device includes a switching transistor that is provided corresponding to the pixel and controls switching of the pixel electrode, and the semiconductor layers constituting the transistor and the switching transistor are identical to each other. It consists of a membrane.

  According to this aspect, since the semiconductor layer constituting the transistor and the semiconductor layer constituting the switching transistor functioning as a pixel switching TFT are formed of the same film, both the semiconductor layers are formed in the same film formation step. It becomes possible to form. Therefore, it is possible to prevent the manufacturing process from becoming long and complicated, and the laminated structure on the substrate from becoming complicated.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  According to the electronic apparatus of the present invention, since the electro-optical device according to the present invention described above is provided, a projection display device, a television, a mobile phone, an electronic notebook, and a word processor capable of performing high-quality display. Various electronic devices such as a viewfinder type or a monitor direct view type video tape recorder, a workstation, a videophone, a POS terminal, and a touch panel can be realized. Further, as the electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  The operation and other advantages of the present invention will become apparent from the best mode for carrying out the invention described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a driving circuit built-in type TFT active matrix driving type liquid crystal device, which is an example of the electro-optical device of the present invention, is taken as an example.

<1. Liquid crystal device>
First, the overall configuration of the liquid crystal device according to the present embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is a schematic plan view showing a configuration of a liquid crystal device when the TFT array substrate 10 is viewed from the counter substrate 20 side together with each component formed thereon, and FIG. 2 is a plan view of FIG. It is HH 'sectional drawing.

  1 and 2, the liquid crystal device according to the present embodiment includes a TFT array substrate 10 and a counter substrate 20 that are arranged to face each other. The TFT array substrate 10 is, for example, a transparent substrate such as a quartz substrate or a glass substrate, or a silicon substrate. The counter substrate 20 is also a substrate made of the same material as the TFT array substrate 10, for example. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are sealed around the image display region 10a where the electro-optical operation is performed. They are bonded to each other by a sealing material 52 provided in the region.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, for example, in the sealing material 52, a gap material 56 such as a glass fiber or a glass bead for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  A data line driving circuit 101, a sampling circuit 7, a scanning line driving circuit 104, and an external circuit connection terminal 102 are formed in the peripheral area located around the image display area 10 a on the TFT array substrate 10.

  In the peripheral region on the TFT array substrate 10, a data line driving circuit 101 and a plurality of external circuit connection terminals 102 are provided along one side of the TFT array substrate 10 on the outer peripheral side of the seal region.

  Further, a region located on the inner side of the seal region in the peripheral region on the TFT array substrate 10 is covered with the frame light shielding film 53 along one side of the image display region 10 a along one side of the TFT array substrate 10. A sampling circuit 7 is arranged.

  The scanning line driving circuit 104 is provided along two sides adjacent to one side of the TFT array substrate 10 so as to be covered with the frame light shielding film 53. Further, in order to electrically connect the two scanning line driving circuits 104 provided on both sides of the image display region 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In the peripheral region on the TFT array substrate 10, vertical conduction terminals 106 are disposed in regions facing the four corners of the counter substrate 20, and vertical conduction is provided between the TFT array substrate 10 and the counter substrate 20. A material is provided corresponding to the vertical conduction terminal 106 and electrically connected to the terminal 106.

  In FIG. 2, on the TFT array substrate 10, a laminated structure is formed in which wirings such as TFTs for pixel switching, scanning lines, and data lines are formed. In the image display area 10a, pixel electrodes 9 are provided in a matrix form on the upper layer of wiring such as pixel switching TFTs, scanning lines, and data lines. The pixel electrode 9 is formed as a transparent electrode made of an ITO film. An alignment film 16 is formed on the pixel electrode 9.

  On the other hand, a light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. The light shielding film 23 is formed of, for example, a light shielding metal film or the like, and is patterned, for example, in a lattice shape in the image display region 10a on the counter substrate 20. On the light shielding film 23 (below the light shielding film 23 in FIG. 2), the counter electrode 21 made of an ITO film is formed, for example, in a solid shape so as to face the plurality of pixel electrodes 9, and further on the counter electrode 21 (FIG. 2, below the counter electrode 21), an alignment film 22 is formed.

  The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films. A liquid crystal storage capacitor is formed between the pixel electrode 9 and the counter electrode 21 by applying a voltage to each of the liquid crystal devices during driving.

  Although not shown here, on the TFT array substrate 10, in addition to the data line driving circuit 101 and the scanning line driving circuit 104, a plurality of data lines are precharged at a predetermined voltage level prior to the image signal. A precharge circuit to be supplied, an inspection circuit for inspecting the quality, defects, etc. of the liquid crystal device during manufacture or at the time of shipment may be formed.

  Next, the electrical configuration of the liquid crystal device according to the present embodiment will be described with reference to FIG. FIG. 3 is a block diagram showing an electrical configuration of the liquid crystal device according to the present embodiment.

  The liquid crystal device according to the present embodiment includes a scanning line driving circuit 104, a data line driving circuit 101, a peripheral area located around the image display area 10a of the TFT array substrate 10 (that is, an area other than the image display area 10a). A sampling circuit 7, an image signal line 171 and a capacitor CA are provided.

  The scanning line driving circuit 104 includes a Y clock signal CLY, an inverted Y clock signal CLYinv, and a Y start pulse DY from an external timing control circuit (not shown) via an external circuit connection terminal 102 (see FIG. 1). Is supplied. When the Y start pulse DY is input, the scanning line driving circuit 104 sequentially generates and outputs the scanning signal Gi (i = 1,..., M) at a timing based on the Y clock signal CLY and the inverted Y clock signal CLYinv. To do. The scanning line driving circuit 104 receives a high-potential-side power supply potential VDD and a potential lower than the high-potential-side power supply potential from an external power supply circuit (not shown) via an external connection terminal 102 (see FIG. 1). The low potential side power supply potential VSS is supplied.

  The data line driving circuit 101 is supplied with an X clock signal CLX, an inverted X clock signal CLXinv, and an X start pulse DX from an external timing control circuit via an external circuit connection terminal 102. When the X start pulse DX is input, the data line driving circuit 101 sequentially generates and outputs a sampling signal Si (i = 1,..., N) at a timing based on the X clock signal CLX and the inverted X clock signal XCLXinv. To do. The data line driving circuit 101 is supplied with a high-potential-side power supply potential VDD and a low-potential-side power supply potential VSS from an external power supply circuit via an external circuit connection terminal 102 (see FIG. 1).

  The sampling circuit 7 includes a plurality of sampling switches 77 provided for each data line 6. Each sampling switch 77 is composed of a P-channel or N-channel single-channel TFT. For this reason, as compared with the case where each sampling switch 77 is composed of complementary TFTs, the area on the TFT array substrate 10 required for disposing each sampling switch 77 can be reduced, so that a plurality of samplings can be obtained. The switches 77 can be arranged at a finer pitch.

  In FIG. 3, the liquid crystal device according to this embodiment includes data lines 6 and scanning lines 11 that are wired vertically and horizontally in an image display region 10 a that occupies the center of the TFT array substrate 10. Pixel portions 700 are provided in a matrix at positions corresponding to intersections at which the data lines 6 and the scanning lines 11 intersect each other. The pixel unit 700 includes a liquid crystal element 118, a pixel switching TFT 30, and a storage capacitor 70.

  The liquid crystal element 118 includes a pixel electrode 9, a counter electrode 21, and a liquid crystal layer 50 sandwiched between the pair of electrodes (see FIG. 2). The pixel electrode 9 holds the liquid crystal capacitance formed between the pixel electrode 9 and the counter electrode 21 for a certain period according to the image signal.

  The TFT 30 as an example of the “switching transistor” in the present invention is provided to apply the image signal supplied from the data line 6 to the selected pixel. The gate of the TFT 30 is electrically connected to the scanning line 11, and the source is electrically connected to the data line 6. The drain of the TFT 30 is electrically connected to the pixel electrode 9 (see FIG. 2) constituting the liquid crystal element 118.

  One capacitor electrode 71 of the storage capacitor 70 is electrically connected to the common potential line 91. The common potential line 91 extends to the peripheral region, and is connected to the connection terminal 102c via the transistor 500 which is a “transistor” in the present invention. The connection terminal 102 c is a part of the external connection terminal 102. (See FIG. 1) Then, the connection terminal 102c is held at the LCCOM voltage by a power supply circuit that is built in an external device connected to the external connection terminal 102 and outputs the LCCOM voltage.

  The storage capacitor 70 is added in parallel with the liquid crystal element 118. Since the voltage of the pixel electrode 9 is held by the storage capacitor 70 for a time that is, for example, three orders of magnitude longer than the time when the image signal is applied, the holding characteristics are improved, so that a high contrast ratio is realized. A specific configuration of the storage capacitor 70 will be described later.

  A gate electrode of the transistor 500 is electrically connected to a power supply potential line 95 to which a high potential side power supply potential VDD is supplied from a power supply circuit provided outside when the liquid crystal device is driven via an external circuit connection terminal 102. . Therefore, the transistor 500 is turned off in the manufacturing process of the liquid crystal device, and is turned on when the liquid crystal device is driven, so that electrical connection between the power supply terminal 102c and the common potential line 91 is switched. Can be controlled. Note that a specific structure of the transistor 500 will be described in detail later. The power supply potential line 95 is an example of the “potential line” according to the present invention.

  Each of the image signal lines 171 is electrically connected to the corresponding data line 6 via the sampling circuit 7. In this embodiment, six systems, that is, six-phase (N = 6) image signals VID1 to VID6 are generated, and six image signal lines 171 are provided corresponding to these six-phase image signals.

  The capacitor part CA is provided on the TFT array substrate 10 on the side opposite to the data line driving circuit 101 with respect to the image display area 10a in the peripheral area of the image display area 10a. The capacitor CA includes a plurality of capacitors 600 as an example of the “holding capacitor” according to the present invention. The plurality of capacitors 600 are electrically connected to the common potential line 91 and each data line 6. The capacitor 600 is connected to the other end of the data line 6 different from the one end to which the data line driving circuit 101 is connected. That is, the data line driving circuit 101 is disposed at one end of the data line 6 and the capacitor 600 is disposed at the other end.

  In the present embodiment, the capacitor CA (in other words, the plurality of capacitors 600) is configured to be provided on the opposite side of the data line driving circuit 101 with respect to the image display area 10a in the peripheral area. The capacitor unit CA may be configured to be provided in another area in the peripheral area or a part of the image display area 10a.

  When the sampling switch 77 is turned on by such a capacitor 600, the image signal potential supplied to the data line 6 becomes smaller than the original image signal potential (that is, pushdown). It can be reduced or prevented. That is, for example, the capacitance around the data line 6 can be appropriately ensured by adding the capacitance of the capacitor 600 to the wiring capacity of the data line 6 or the capacitance generated by the overlapping of the data line 6 and another wiring. Can do. Therefore, it is possible to suppress a change in the potential that the data line 6 should hold, that is, a push-down of the image signal potential written to the data line 6. As a result, it is possible to reduce or prevent the occurrence of display unevenness along, for example, the data line 6 due to the push-down of the image signal potential written to the data line 6.

  Next, the operation principle of the liquid crystal device according to this embodiment will be described.

  3, the liquid crystal device according to the present embodiment adopts a TFT active matrix driving method, applies scanning signals G1, G2,..., Gm from the scanning line driving circuit 104 to the respective scanning lines 11 line-sequentially, and TFT 30 An image signal is applied from the data line driving circuit 101 to the data line 11 in the column of the selected pixel region in the horizontal direction in which is turned on. At this time, the image signal may be supplied to each data line 6 line-sequentially. Thereby, an image signal is supplied to the pixel electrode 9 in the selected pixel region. In the liquid crystal device according to the present embodiment, the TFT array substrate 10 and the counter substrate 20 are disposed to face each other via the liquid crystal layer 50 (see FIG. 2). By applying an electric field to the layer 50, the amount of transmitted light between the two substrates is controlled for each pixel, and an image is displayed in gradation.

  Image signals VID <b> 1 to VID <b> 6 that are serially and parallelly developed in six phases are supplied to each pixel unit 700 via N image signals 171 in this embodiment. As will be described below, the data lines 6 are sequentially driven for each data line group including six data lines 6 corresponding to the number of image signal lines 171 as a group.

  A sampling signal Si (i = 1, 2,..., N) is sequentially supplied from the data line driving circuit 101 to each sampling switch 77 corresponding to the data line group, and each sampling switch 77 is turned on according to the sampling signal Si. It becomes.

  Therefore, the image signals VID1 to VID6 are simultaneously supplied from each of the six image signal lines 171 to the data lines 6 belonging to the data line group and sequentially for each data line group through the sampling switch 77 switched to the ON state. Thus, the data lines 6 belonging to one data line group are driven simultaneously. Therefore, according to the liquid crystal device according to the present embodiment, since the data lines 6 are driven for each data line group, the driving frequency can be suppressed.

  An applied voltage defined by the potentials of the pixel electrode 9 and the counter electrode 21 is applied to the liquid crystal element 118. The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The light transmittance is increased, and light having a contrast according to the image signals VID1 to VID6 is emitted from the liquid crystal device according to the present embodiment as a whole, and an image is displayed.

  Next, a specific configuration of the pixel unit 700 of the liquid crystal device according to the present embodiment will be described with reference to FIG. In FIG. 4, in order to make each layer and each member recognizable on the drawing, the scale is different for each layer and each member. In FIG. 4, for convenience of explanation, illustration of a portion located above the pixel electrode 9 is omitted.

  As shown in FIG. 4, on the TFT array substrate 10, various components such as the pixel electrode 9 described above have a laminated structure. Specifically, the scanning line 11 is formed on the TFT array substrate 10, and the semiconductor layer 30 a constituting the pixel switching TFT 30 is formed on the upper layer side via the base insulating film 12.

  In FIG. 4, the TFT 30 includes a semiconductor layer 30a and a gate electrode 30b. The TFT 30 is an example of the “switching transistor” according to the present invention.

  The semiconductor layer 30a includes a source region 30a1, a channel region 30a2, a drain region 30a3, a source region side LDD region 30a4 formed between the source region 30a1 and the channel region 30a2, and a drain formed between the channel region 30a2 and the drain region 30a3. It consists of a region side LDD region 30a5. That is, the TFT 30 has an LDD structure.

  The source region 30a1 is electrically connected to the data line 6 through a contact hole 81 opened in the gate insulating film 41 and the interlayer insulating film. On the other hand, the drain region 30 a 3 is electrically connected to the drain relay wiring 7 formed in the contact hole 82 opened in the gate insulating film 41 and the interlayer insulating film 42. Further, the drain relay wiring 7 is electrically connected to the pixel electrode 9 through a contact hole 83 opened in the interlayer insulating film 43.

  The source region 30a1 and the drain region 30a3 are formed substantially in mirror symmetry with respect to the channel region 30a2. The source region 30a1, the channel region 30a2, the drain region 30a3, the source region side LDD region 30a4, and the drain region side LDD region 30a5 are impurity regions formed by implanting impurities into the semiconductor layer 30a by, for example, impurity implantation such as ion implantation. is there. The source region side LDD region 30a4 and the drain region side LDD region 30a5 are each formed as a low concentration impurity region having less impurities than the source region 30a1 and the drain region 30a3. According to such an impurity region, when the TFT 30 is not operating, the off-current flowing between the source region and the drain region can be reduced, and a decrease in the on-current flowing when the TFT 30 is operating can be suppressed. The TFT 30 preferably has an LDD structure. However, the TFT 30 may have an offset structure in which no impurity is implanted into the source region side LDD region 30a4 and the drain region side LDD region 30a5. A self-aligned type in which a source region and a drain region are formed by implanting at a high concentration may be used.

  In FIG. 4, the gate electrode 30b is disposed on the upper layer side of the semiconductor layer 30a via the gate insulating film 41, and is formed so as to face the channel region 30a2. The interlayer insulating film 41 is formed over almost the entire surface of the TFT array substrate 10. The gate insulating film 41 is made of, for example, conductive polysilicon.

In FIG. 4, the scanning line 11 is provided on the lower layer side of the semiconductor layer 30 a on the TFT array substrate 10 through the base insulating film 12. The scanning line 11 is, for example, tungsten (W),
It is made of a light-shielding conductive material such as a refractory metal material such as Ti or TiN. According to such a scanning line 11, the TFT 30 receives the return light such as the back surface reflection on the TFT array substrate 10 or the light emitted from another liquid crystal device by a multi-plate projector or the like and penetrating the composite optical system. The channel region 30a2 and the drain region side LDD region 30La5 can be shielded almost or completely. In particular, in the present embodiment, the scanning line 11 is formed wider than the semiconductor layer 30a, so that light that is incident on the TFT array substrate 10 from the lateral direction or obliquely toward the semiconductor layer 30a is also shielded. Is configured to enhance.

  In FIG. 4, the base insulating film 12 is made of, for example, a silicon oxide film. The base insulating film 12 is formed on the entire surface of the TFT array substrate 10 in addition to the function of insulating the semiconductor layer 30a from the scanning line 11, so that it remains after polishing the surface of the TFT array substrate 10 or after cleaning. It has a function of preventing deterioration of the characteristics of the TFT 30 due to dirt or the like.

  In FIG. 4, the data line 6 and the drain relay wiring 7 are provided on the upper layer side of the semiconductor layer 30 a on the TFT array substrate 10 via the gate insulating film 41. The data line 6 is electrically connected to the source region 30a1 of the TFT 30 through a contact hole 81 opened in the interlayer insulating film 41. Since the contact hole 81 penetrates only one layer of the interlayer insulating film (that is, the interlayer insulating film 41), the depth thereof can be relatively short, and the opening can be easily performed by etching or the like. Further, since the aspect ratio is small, a good contact can be easily formed even at the bottom. The drain relay wiring 7 is electrically connected to the drain region 30a3 of the TFT 30 through a contact hole 83 opened in the first interlayer insulating film 41, and is a contact opened through the interlayer insulating film 43. The pixel electrode 9 is electrically connected through a hole 85. Therefore, it is possible to avoid a situation where the interlayer distance between the drain relay wiring 7 and the drain region 30a3 is long and it is difficult to connect the two with a single contact hole. Furthermore, the presence of the drain relay wiring 7 can reduce the electrical resistance between the pixel electrode 9 and the drain region 30a3.

  Here, both the data line 6 and the drain relay line 7 are made of a conductive material having a light shielding property. By providing the data line 6 and the drain relay wiring 7 in this way, the semiconductor layer 30a can be effectively protected from light entering from above the TFT array substrate 10. In particular, in this embodiment, the data line 6 and the drain relay wiring 7 are formed wider than the semiconductor layer 30a, so that not only the light entering from directly above the TFT array substrate 10, but also the lateral or oblique incidence. It is formed so as to improve the light shielding property against the light to be attempted. By providing the upper light shielding film in this way, light leakage current generated in the semiconductor layer 30a can be suppressed, and malfunction of the TFT 30 can be prevented.

  Further, on the upper layer side, the capacitor electrode 71 is disposed so as to face the pixel electrode 9 with the capacitor insulating film 75 interposed therebetween, and the storage capacitor 70 is formed. The capacitive electrode 71 corresponds to the “first conductive layer” in the present invention. The capacitor electrode 71 is formed on the lower layer side of the pixel electrode 9 with the capacitor insulating film 75 interposed therebetween, and is formed of the same first conductive material as that of the pixel electrode 9. In this manner, by forming the pixel electrode 9 and the capacitor electrode 71 with the same material, it is possible to reduce the types of treatment liquids such as a stripping liquid used in the manufacturing process of the liquid crystal device, and to reduce the cost of the liquid crystal device. It can be manufactured. Further, it is effective in reducing the number of steps in the manufacturing process of the liquid crystal device. Further, if the pixel electrode 9 and the capacitor electrode 71 are formed of the same conductive material, even if the pixel electrode 9 and the capacitor electrode 71 are exposed to a treatment solution such as a stripping solution in the manufacturing process, the pixel electrode 9 and the capacitor electrode 71 are eroded. Nor.

  Particularly in the present embodiment, both the pixel electrode 9 and the capacitor electrode 71 are made of ITO. Since ITO is a transparent conductive material, by using it for the pixel electrode arranged for each pixel or the capacitor electrode 71 formed on the lower layer side of the pixel electrode, without reducing the transmittance of the liquid crystal device, Image signals can be transmitted satisfactorily, and high-quality image display can be realized.

  The capacitor electrode 71 is electrically connected to the common potential line 91 and is held at the common potential LCCOM (see FIG. 3). The capacitor insulating film 75 is a single-layer structure made of, for example, a silicon oxide (SiO 2) film such as an HTO (High Temperature Oxide) film, an LTO (Low Temperature Oxide) film, a silicon nitride (SiN) film, or the like. It may be formed so as to have a multilayer structure.

  As described above, by forming the storage capacitor 70, the potential holding characteristic of the pixel electrode 9 is improved, and display characteristics such as improvement of contrast and reduction of flicker can be improved. In addition, since the storage capacitor 70 is formed by the pixel electrode 9 and the capacitor electrode 71, for example, compared to a case where the storage capacitor is formed by providing an upper electrode and a lower electrode in addition to the pixel electrode 9, the device configuration Can be simplified. Furthermore, since the capacitor electrode 71 is provided on the lower layer side than the pixel electrode 9, electrical or electromagnetic coupling between the pixel electrode 9 and the lower layer side (for example, the data line 6) of the capacitor electrode 71 is prevented. It can also function as a shield layer. Therefore, it is possible to reduce the possibility of potential fluctuations or the like in the pixel electrode 9.

  Next, referring to FIG. 5, the laminated structure in the peripheral region will be specifically described. FIG. 5 is a cross-sectional view schematically showing a laminated structure in the peripheral region. In FIG. 5, the scales of the layers and members are different from each other in order to make the layers and members recognizable on the drawing.

  In the peripheral region, a transistor 500, which is an example of the “transistor” of the present invention, is formed on the TFT array substrate 10 via the base insulating film 12. The transistor 500 includes a semiconductor layer 500a and a gate electrode 500b disposed with the gate insulating film 41 interposed therebetween. Further, the semiconductor layer 500a is formed between the source region 500a1, the channel region 500a2, the drain region 500a3, the source region side LDD region 500a4 formed between the source region 500a1 and the channel region 500a2, and between the channel region 500a2 and the drain region 500a3. The drain region side LDD region 500a5 is formed. The gate electrode 500b is disposed so as to oppose the channel region 500a2. The gate electrode 500b is made of conductive polysilicon, like the TFT 30 in the image display region 10a.

  The source region 500 a 1 is electrically connected to the common potential line 91 via the source relay wiring 94 formed in the contact hole 84. As described above, the common potential line 91 is held at the LCCOM potential. The common potential line 91 is formed of the same material as the pixel electrode 9 and the capacitor electrode 71, that is, ITO in this embodiment. Here, the source relay wiring 94 is made of aluminum having good conductivity. As described above, on the source region 500a1 side of the transistor 500, the source relay wiring 94 formed of aluminum and the common potential line 91 formed of ITO are electrically connected. Therefore, there is no electric corrosion at the location during the manufacturing process.

  The common potential line 91 is formed in the same layer as the capacitor electrode 71 in the image display region 10a (see FIG. 4). Specifically, the common potential line 91 and the capacitor electrode 71 are formed from the same film on the TFT array substrate 10 and are formed by patterning.

  A storage capacitor electrode 93 is formed on the common potential line 91 via a capacitor insulating film 75. That is, a capacitor 600 (see FIG. 3) having the common potential line 91 and the additional capacitance electrode 93 as a pair of electrodes is formed in the peripheral region. By providing the capacitor 600 in this manner, when the sampling switch 77 is switched to the ON state, the image signal potential supplied to the data line 6 becomes smaller than the original image signal potential (that is, push). Down) can be reduced or prevented.

  In the present embodiment, the storage capacitor line 93 is also made of ITO. In this way, by forming the storage capacitor line 93 with the same material as the capacitor electrode 71 in the image display region 10a, it is possible to reduce the types of treatment liquids such as a stripping liquid used in the manufacturing process of the liquid crystal device, A liquid crystal device can be manufactured at a lower cost. Furthermore, it is possible to prevent the occurrence of electrolytic corrosion due to a processing solution such as a stripping solution in the manufacturing process.

  On the other hand, the drain region 500 a 3 of the transistor 500 is electrically connected to the power supply line 92 formed on the upper layer side through the contact hole 86. The power supply line 92 is connected to the output terminal of a power supply circuit (not shown in FIG. 5) provided in the peripheral region, and is held at the LCCOM potential. In the present embodiment, in particular, the power supply line 92 is formed of aluminum having good conductivity like the source relay wiring 94, and both are formed in the same layer. That is, the power supply line 92 and the source relay wiring 94 are formed on the same base layer by patterning the same film, that is, the aluminum film formed in the same process.

  The power supply line 92 in the present embodiment is an example of the “second conductive layer” in the present invention. In this embodiment, in particular, the power supply line 92 is configured as a wiring for supplying a constant potential (that is, LCCOM potential) to the capacitor electrode 71, the common potential line 91, and the like. The power supply line 92 and the common potential line 91 arranged in the peripheral region can also function as a shield layer that prevents electrical or electromagnetic coupling with the lower layer side (for example, the data line 6).

  The power supply line 92 and the source relay wiring 94 are made of a conductive material having a different ionization tendency from the common potential line 91, the pixel electrode 9, and the capacitor electrode 71. In this embodiment, in particular, the power supply line 92 and the source relay wiring 94 are made of aluminum that has a higher ionization tendency than ITO. Therefore, if the common potential line 91, the power supply line 92, and the source relay wiring 94 are directly and electrically connected, the power supply line 92 and the source formed of aluminum are exposed when exposed to an acid such as a stripping solution. Electrons move from the relay wiring 94 to the common potential line 91 formed of ITO, and the aluminum atoms constituting the power supply line 92 and the source relay wiring 94 are dissolved into an acid such as a stripping solution as ions. Therefore, in this embodiment, as shown in FIG. 5, the electrolytic corrosion is prevented from occurring by interposing the transistor 500 between the power supply line 92 and the common potential line 91. That is, in the manufacturing process, since the driving voltage is not applied to the gate electrode 500b, the transistor 500 is off. Therefore, the power supply line 92 and the common potential line 91 are electrically insulated from each other, and even when exposed to an acid such as a stripping solution at the same time, electrons do not move between them. For this reason, even if a potential difference is generated between the power supply line 92 and the common potential line 91 in the manufacturing process, no electrolytic corrosion occurs.

  On the other hand, during the operation of the liquid crystal device, the LCCOM voltage is applied to the common potential line 91 by applying a turn-on voltage to the gate electrode 500b to short-circuit the source region 500a1 and the drain region 500a3 of the transistor 500. be able to.

  As described above, according to the present embodiment, it is possible to prevent the occurrence of galvanic corrosion in a wet treatment process that is exposed to an acid such as a stripping solution, so that wiring and the like in a laminated structure can be produced with high quality. As a result, it is possible to reduce a loss or noise when the image signal propagates through the wiring or the like, and to realize a liquid crystal device capable of displaying a high-quality image.

  In this embodiment, the transistor 500 is provided in the peripheral region. However, by arranging the transistor 500 in the image display region 10a and extending the common potential line 91 to the peripheral region, a constant potential is applied to the power supply line 92. You may supply.

<Modification>
Subsequently, a modification of the above-described embodiment will be described with reference to FIG. In the liquid crystal device according to this modification, the capacitor 600 is provided in the peripheral region as in the above-described embodiment, but the ITO layer (that is, the common potential line 91 and the storage capacitor line 93) formed over two layers. ) Is different from the above-described embodiment in that the layer formed on the upper side functions as a common potential line. That is, in FIG. 5, the lower ITO layer extends to the peripheral region as the common potential line 91 and is connected to the power supply line 92 via the transistor 500, but as in the present modification shown in FIG. 6, The upper ITO layer may be extended to the peripheral region as the common potential line 91 and connected to the power supply line 92 via the transistor 500. The laminated structure other than the capacitor 600 is the same as in FIG.

  In this modification, the transistor 500 is provided in the peripheral region. However, by arranging the transistor 500 in the image display region 10a and extending the common potential line 91 to the peripheral region, a constant potential is applied to the power supply line 92. You may supply.

<Electronic equipment>
Next, the case where the liquid crystal device which is the above-described electro-optical device is applied to various electronic devices will be described.

  FIG. 7 is a plan view showing a configuration example of the projector. Hereinafter, a projector using the liquid crystal device as a light valve will be described.

  As shown in FIG. 7, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Therefore, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B.

  In addition, since light corresponding to each primary color of R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 7, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type, a monitor direct-view type video tape recorder, a car navigation device, a pager, an electronic device Examples include a notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel. Needless to say, the present invention can be applied to these various electronic devices.

  In addition to the liquid crystal devices described in the above embodiments, the present invention includes a reflective liquid crystal device (LCOS), a plasma display (PDP), a field emission display (FED, SED), an organic EL display, and a digital micromirror device. (DMD), electrophoresis apparatus and the like are also applicable.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, In addition, an electronic apparatus including the electro-optical device is also included in the technical scope of the present invention.

It is a top view which shows the whole structure of the liquid crystal device which concerns on 1st Embodiment. It is H-H 'sectional drawing of FIG. 1 is a block diagram illustrating an electrical configuration of a liquid crystal device according to a first embodiment. It is sectional drawing which shows the laminated structure in the image display area | region of the liquid crystal device which concerns on this embodiment. It is sectional drawing which shows the laminated structure in the peripheral region of the liquid crystal device which concerns on this embodiment. It is sectional drawing which shows the laminated structure in the peripheral region of the liquid crystal device which concerns on a modification. It is a top view which shows the structure of the projector which is an example of the electronic device to which the electro-optical apparatus is applied.

Explanation of symbols

  6 data line, 7 drain relay wiring, 9 pixel electrode, 10 TFT array substrate, 10a image display area, 11 scanning line, 12 base insulating film, 30 TFT, 70 storage capacitor, 71 capacitive electrode, 75 capacitive insulating film, 91 common Potential line, 92 power line, 93 storage capacitor electrode, 102 external connection terminal, 500 transistor, 600 capacitor

Claims (7)

On the board
A plurality of pixel electrodes comprising a first conductive material and arranged in a pixel region;
A first conductive layer comprising the same material as the first conductive material, and constituting at least part of wiring, electrodes and electronic elements for performing an electro-optic operation in the pixel region;
A second conductive layer comprising a second conductive material having an ionization tendency different from that of the first conductive material, and constituting at least another part of the wiring, the electrode, and the electronic element;
One of the source and the drain is electrically connected to one of the first conductive layer and the second conductive layer, and the other of the source and the drain is connected to the first conductive layer and the second conductive layer. An electro-optical device comprising: a thin film transistor electrically connected to the other of the first and second thin film transistors that relay-connects the first conductive layer and the second conductive layer by applying a voltage to the gate.   2. The electro-optical device according to claim 1, wherein the pixel electrode and the first conductive layer are disposed to face each other with a capacitor insulating film therebetween, thereby forming a storage capacitor.   The electro-optical device according to claim 1, wherein the first conductive material is ITO (Indium Tin Oxide).   4. The electro-optical device according to claim 1, wherein the second conductive layer constitutes an external connection terminal arranged in a peripheral region located around the pixel region. 5. A potential line for supplying a predetermined potential on the substrate;
The electro-optical device according to claim 1, wherein the gate is electrically connected to the potential line. A switching transistor that is provided corresponding to the pixel electrode and controls the switching of the pixel electrode;
6. The electro-optical device according to claim 1, wherein the semiconductor layers constituting the transistor and the switching transistor are made of the same film.   An electronic apparatus comprising the electro-optical device according to claim 1.

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