JP2017227672A - Substrate with transparent conductive film, liquid crystal panel and method for producing substrate with transparent conductive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate with a transparent conductive film that is resistant to temporal degradation, a liquid crystal panel and a substrate with a transparent conductive film.SOLUTION: A substrate with a transparent conductive film has a substrate 11 having a first face 11a and a second face 11b, a first transparent conductive film 12 provided on the first face 11a and composed of indium tin oxide, and a second transparent conductive film 13 provided on the first transparent conductive film 12 and composed of silicon oxide and tin oxide.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a substrate with a transparent conductive film, a liquid crystal panel, and a method for producing a substrate with a transparent conductive film.

  Conventionally, a liquid crystal display device with a touch panel having a function of detecting a touch position on a screen has been realized. For example, a liquid crystal display device with a touch panel is configured by pasting a touch panel on a display surface of a liquid crystal panel. Recently, an in-cell type liquid crystal panel in which a detection electrode of a touch panel is incorporated in a liquid crystal display panel constituting a display device has been considered.

  A so-called lateral electric field driving method that drives the liquid crystal by generating an electric field in the horizontal direction with respect to the liquid crystal panel substrate, such as an IPS (In-Plane Switching) method or an FFS (Fringe Field Switching) method for driving the liquid crystal, is adopted. An in-cell type liquid crystal panel generally has the following structure. That is, a counter substrate including a color filter substrate, a liquid crystal driving electronic circuit that drives liquid crystal, and a sensing sensor electrode that detects touch, and a liquid crystal sandwiched between these substrates are provided.

  In the in-cell type liquid crystal panel adopting such a lateral electric field driving method, an electrode is not formed on the color filter substrate and the color filter is charged, thereby causing a malfunction of the display operation. In order to prevent such charging, a transparent conductive film containing silicon with a high resistance indium tin oxide as a main material may be provided on the surface of the color filter substrate where the color filter is not formed to prevent charging. It has been proposed (see, for example, Patent Document 1).

Japanese Patent No. 5855948

However, a conductive film containing indium tin oxide as a main material and containing silicon has a problem in weather resistance and chemical resistance because indium tin oxide is exposed on the surface thereof, and is likely to deteriorate over time.
In view of the circumstances as described above, an object of the present invention is to provide a substrate with a transparent conductive film, a liquid crystal panel, and a substrate with a transparent conductive film that are less likely to deteriorate with time.

In order to achieve the above object, a substrate with a transparent conductive film according to one embodiment of the present invention includes a substrate, a first transparent conductive film, and a second transparent conductive film.
The substrate has a first surface and a second surface.
The first transparent conductive film is provided on the first surface and is made of indium tin oxide.
The second transparent conductive film is provided on the first transparent conductive film and includes silicon oxide and tin oxide.

In such a substrate with a transparent conductive film of the present invention, since the second transparent conductive film is provided on the first transparent conductive film, the first transparent conductive film (ITO film) and the second transparent conductive film are provided. There is little change with time of the sheet resistance of the laminated film composed of the film (ST film). In the case of a single ITO film, oxygen escapes from the ITO film, so the sheet resistance changes with time. On the other hand, in the case of a laminated film of an ITO film and an ST film, oxygen on the surface of the ITO film. It is considered that the loss of oxide (reduction of oxide) can be suppressed by the ST film, and as a result, the change with time of the sheet resistance of the laminated film can be reduced.
The first transparent conductive film (ITO film) is made of indium tin oxide, which contains indium tin oxide as a main component and contains a trace amount of elements such as Al and Zr mixed in the target manufacturing process. It is sufficient that the effects of the present invention can be obtained.

A substrate with a transparent conductive film, wherein the laminated film of the first transparent conductive film and the second transparent conductive film has a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ and transmission at a wavelength of 550 nm. The rate may be 95% or more. By using such a substrate with a transparent conductive film for an in-cell type liquid crystal panel, it is possible to prevent the charging of the substrate with the transparent conductive film by the laminated film while enabling touch sensing during a touch operation, and stable A liquid crystal panel having a touch panel function and display characteristics is obtained.

  In the substrate with a transparent conductive film, a color filter may be provided on the second surface. Thus, for example, it can be applied to a color filter substrate used in a liquid crystal panel or the like, and when this is used in a liquid crystal panel, charging to the color filter can be prevented by the laminated film, and malfunction due to charging can be prevented.

  The substrate with a transparent conductive film, wherein the first transparent conductive film has a thickness of 10 nm to 20 nm, the second transparent conductive film has a thickness of 20 nm to 55 nm, The refractive index of the transparent conductive film 2 may be 1.6 to 1.8. By adopting such a configuration, a laminated film of the first transparent conductive film and the second transparent conductive film that retains high transmittance, exhibits a desired sheet resistance, and has little change in sheet resistance with time can be obtained. .

  If the film thickness of the first transparent conductive film is thinner than 10 nm, the sheet resistance is too high, and if it is thicker than 20 nm, the transmittance is lowered when a laminated film is formed. Further, if the thickness of the second transparent conductive film is less than 20 nm, a sufficient barrier function for suppressing oxygen escape from the surface of the first transparent conductive film cannot be obtained. The transmittance will be low. Further, a high transmittance laminated film can be obtained by setting the refractive index of the ST film to 1.6 to 1.8.

A liquid crystal panel according to one embodiment of the present invention includes a color filter substrate, a counter substrate, and a liquid crystal.
The color filter substrate includes a first substrate having a first surface and a second surface, a first transparent conductive film made of indium tin oxide provided on the first surface, and the first substrate. A laminated film of a second transparent conductive film containing silicon oxide and tin oxide provided on the transparent conductive film; and a color filter provided on the second surface.
The counter substrate includes a second substrate, a sensing sensor electrode and a liquid crystal driving electronic circuit provided on one surface of the second substrate.
The liquid crystal is sandwiched between substrates arranged such that the second surface of the color filter substrate and the one surface of the counter substrate face each other, and are driven and controlled by the liquid crystal driving electronic circuit.

  In such a liquid crystal panel of the present invention, since the color filter is prevented from being charged by the laminated film, there is no malfunction due to charging. Since this laminated film is formed by forming the second transparent conductive film (ST film) on the first transparent conductive film (ITO film), oxygen escapes from the ITO film surface (oxide) Reduction) is suppressed by the ST film, and as a result, the change in sheet resistance of the laminated film with time can be reduced. Therefore, it is possible to obtain a highly reliable liquid crystal panel with little change in touch sensing function over time.

In the liquid crystal panel, a sheet resistance of a laminated film of the first transparent conductive film and the second transparent conductive film is 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □, and a transmittance at a wavelength of 550 nm is 95. % Or more. As a result, an antistatic effect can be obtained while enabling touch sensing during a touch operation, and a liquid crystal panel having stable display characteristics can be obtained.

  In the liquid crystal panel, the first transparent conductive film has a thickness of 10 nm to 20 nm, the second transparent conductive film has a thickness of 20 nm to 55 nm, and the second transparent conductive film. The conductive film may have a refractive index of 1.6 to 1.8.

  With such a configuration, a laminated film of the first transparent conductive film and the second transparent conductive film is obtained that maintains high transmittance, obtains a desired sheet resistance, and has little change in sheet resistance over time. It is done. If the film thickness of the first transparent conductive film is thinner than 10 nm, the sheet resistance is too high, and if it is thicker than 20 nm, the transmittance is lowered when a laminated film is formed. Further, if the thickness of the second transparent conductive film is less than 20 nm, a barrier function of suppressing the escape of oxygen from the first transparent conductive film cannot be obtained sufficiently. The transmittance will be low. A decrease in transmittance can be prevented by setting the refractive index of the second transparent conductive film to 1.6 to 1.8.

In a method for manufacturing a substrate with a transparent conductive film according to one embodiment of the present invention, a first transparent conductive film is formed and a second transparent conductive film is formed.
The first transparent conductive film is formed by using a target made of indium tin oxide on the other surface of the substrate provided with a color filter on one surface, and an oxygen partial pressure of 0.0225 to 0.0325 Pa. The film is formed in a mixed gas atmosphere of argon and oxygen.
The film formation of the second transparent conductive film uses a target composed of silicon and tin oxide on the first transparent conductive film, and a mixed gas of argon and oxygen having an oxygen partial pressure of 1.3 to 2.7 Pa. Film formation is performed under an atmosphere.

By forming the first transparent conductive film in such an atmosphere, in order to obtain the desired high sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □, a large amount of oxygen is present in the film. The taken-in first transparent conductive film can be obtained. Then, by forming the second transparent conductive film on the first transparent conductive film, oxygen escape (reduction of oxide) on the surface of the first transparent conductive film can be suppressed, and the first transparent conductive film A substrate with a transparent conductive film in which the sheet resistance of the laminated film of the film and the second transparent conductive film is little changed with time is obtained.

  Moreover, the second transparent conductive film having a desired refractive index can be formed by forming the second transparent conductive film in the above-described mixed gas atmosphere having an oxygen partial pressure.

  In the method for manufacturing a substrate with a transparent conductive film, the film formation of the first transparent conductive film and the film formation of the second transparent conductive film may be performed at 60 ° C. or less. Since the film is formed at 60 ° C. or lower as described above, the first transparent conductive film and the second transparent conductive film can be formed without deteriorating the color filter even when the color filter is formed on the substrate. Can do.

  As described above, according to the present invention, a laminated film of an ITO film, a (first transparent conductive film), and an ST film (second transparent conductive film) with little deterioration with time can be obtained as an antistatic film. Thus, a substrate with a transparent conductive film, a liquid crystal panel, and a substrate with a transparent conductive film, which have stable operating characteristics over a long period of time, can be obtained.

It is a schematic sectional drawing of the liquid crystal panel which concerns on one Embodiment of this invention. It is a figure which shows the time-dependent change of the sheet resistance of the board | substrate with a transparent conductive film which concerns on one Embodiment of this invention, and the board | substrate with a transparent conductive film as a comparative example. It is a figure which shows the time-dependent change of the sheet resistance of the board | substrate with a transparent conductive film and color filter board | substrate which concern on one Embodiment of this invention. The time-dependent change of the sheet resistance of the board | substrate with a transparent conductive film produced by making ST film 55nm and changing the film thickness of ITO film | membrane is shown. The time-dependent change of the sheet resistance of the board | substrate with a transparent conductive film produced by making ST film into 20 nm and changing the film thickness of an ITO film | membrane is shown. The time-dependent change of the sheet resistance of the board | substrate with a transparent conductive film produced by making ST film into 10 nm and changing the film thickness of an ITO film | membrane is shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, an in-cell type liquid crystal panel with a touch panel function that employs the FFS method will be described as an example, but the present invention is not limited thereto. For example, the present invention can also be applied to an IPS liquid crystal panel. Among a pair of substrates constituting the liquid crystal panel, one substrate is provided with a liquid crystal driving electronic circuit and an electrode for a sensing sensor, and no electrode is formed on the other substrate. The present invention can be applied to a configuration in which a color filter is formed.

[LCD panel]
FIG. 1 is a cross-sectional view schematically showing a liquid crystal panel 1 according to an embodiment of the present invention. As shown in FIG. 1, a liquid crystal panel 1 includes a color filter substrate 10 as a substrate with a transparent conductive film arranged with a predetermined gap, a counter substrate 20, a liquid crystal 40, a color filter substrate 10, and a counter substrate. 20 includes a pair of polarizing plates 50 and 51 provided so as to sandwich 20 and a cover glass 60 provided on the color filter substrate 10 side.

  The liquid crystal panel 1 has a function of displaying an image and a touch panel function.

  As shown in FIG. 1, a backlight is disposed on the counter substrate 20 side. A cover glass 60 is disposed on the color filter substrate 10 side, and a touch operation is performed by touching the surface of the cover glass 60 with a finger 70 or the like. Moreover, the cover glass 60 side becomes a display screen.

  The color filter substrate 10 includes a first glass substrate 11, a color filter 15, and an antistatic film 14.

  The first glass substrate 11 has a first surface 11a and a second surface 11b.

  The color filter 15 is formed on the second surface 11 b of the first glass substrate 11. The color filter 15 includes a black matrix formed in a lattice shape with a black resin and the like, and a red colored layer, a green colored layer, and a blue colored layer formed in, for example, stripes so as to fill the openings of the black matrix. An alignment film (not shown) is formed on the color filter 15.

  The openings formed by the grid-like black matrix correspond to sub-pixels, and one pixel is composed of three sub-pixels, a red sub-pixel, a green sub-pixel, and a blue sub-pixel.

  The antistatic film 14 as a transparent conductive film is provided on the first surface 11 a of the first glass substrate 11. The antistatic film 14 is a laminated film of an ITO film 12 as a first transparent conductive film made of indium tin oxide (ITO) and an ST film 13 as a second transparent conductive film containing silicon oxide and tin oxide. It is. The ITO film 12 constituting the antistatic film 14 is formed on the first surface 11 a of the glass substrate 11, and the ST film 13 is formed on the ITO film 12.

The antistatic film 14 is a film having a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ and a transmittance of 95% or more at a wavelength of 550 nm. The color filter 15 removes charges from the charged color filter 15. This prevents the charging of the battery. By setting the sheet resistance of the antistatic film 14 in this way, the antistatic film 14 has a charge removing function and can perform touch sensing during a touch operation.

  In the present embodiment, the antistatic film 14 is composed of a laminated film of the ITO film 12 and the ST film 13. When the antistatic film is composed of a single ITO film, the sheet resistance of the ITO film decreases with time, and the touch sensing function deteriorates. This is presumably because the sheet resistance decreases as oxygen contained in the ITO film escapes. On the other hand, in this embodiment, the antistatic film 14 with little change in sheet resistance with time could be obtained by laminating the ST film 13 on the ITO film 12. This is presumably because the ST film 13 suppresses the escape of oxygen (reduction of oxide) from the surface of the ITO film 12 and functions as a reduction preventing film.

  The ITO film 12 preferably has a thickness of 10 to 20 nm. If the film thickness is less than 10 nm, the sheet resistance immediately after the film formation becomes higher than the desired resistance value, and when the antistatic film 14 is formed, a sufficient charge removal function cannot be provided. If the film thickness is greater than 20 nm, the transmittance will be low when the ST film 13 is laminated to form the antistatic film 14.

  The ST film 13 is desirably 20 to 55 nm thick. When the thickness is less than 20 nm, it is not possible to sufficiently obtain a barrier function of suppressing the escape of oxygen from the ITO film 12. Moreover, the transmittance | permeability will become low that it is a film thickness thicker than 55 nm. The ST film 13 preferably has a refractive index of 1.6 to 1.8. By setting the refractive index in this way, the antistatic film 14 having a high transmittance can be obtained.

  Thus, the ST film 13 functions as a barrier function that suppresses oxygen escape from the surface of the ITO film 12. Since the ST film 13 is transparent and conductive, and the refractive index can be adjusted by the ratio of oxygen introduced during film formation, and the lower refractive index can be easily obtained, the antistatic film 14 can obtain desired characteristics. It is easy to adjust and is optimal as a film laminated on the ITO film 12.

  The counter substrate 20 includes a second glass substrate 21 and a layer 22 including a sensing sensor electrode and a liquid crystal driving electronic circuit.

  The second glass substrate 21 has a first surface 21a and a second surface 21b. The layer 22 including the sensing sensor electrode and the liquid crystal driving electronic circuit is formed on the second surface 21 b which is one surface of the second glass substrate 21. An alignment film (not shown) is formed on the layer 22 including the sensing sensor electrode and the liquid crystal driving electronic circuit.

  The liquid crystal driving electronic circuit drives the liquid crystal 40. The sensing sensor electrode constitutes a part of the sensing sensor, and senses a touch operation on the surface of the cover glass 60.

  The layer 22 including the sensing sensor electrode and the liquid crystal driving electronic circuit includes a pixel electrode, a TFT (Thin Film Transistor), a gate line, a signal line, a common electrode, a common electrode driving line, and a sensing sensor. It has a drive line and a detection line for a sensing sensor.

  The electronic circuit for driving liquid crystal includes a pixel electrode, a TFT (Thin Film Transistor), a gate line, a signal line, a common electrode, and a common electrode driving line. These liquid crystal drive electronic circuits are driven and controlled by a drive control circuit provided on a drive circuit board (not shown) that is electrically connected to the liquid crystal panel.

  The sensing sensor electrode includes a sensing sensor drive line, a sensing sensor detection line, and a common electrode. The sensing sensor includes these sensing sensor electrodes and a touch position detection control circuit, and the touch position detection control circuit is provided on a drive circuit board (not shown) that is electrically connected to the liquid crystal panel. By providing the sensing sensor, the liquid crystal panel has a touch panel function. The common electrode used for driving the liquid crystal also functions as a sensor electrode.

  As described above, the counter substrate 20 includes a liquid crystal driving electronic circuit that generates an image to be displayed on the display screen of the liquid crystal panel 1, and a detection sensor that detects a touch by an instrument such as a finger 70 or a touch pen on the surface of the liquid crystal panel 1. A part of is provided.

  When the horizontal plane of the second glass substrate 21 is an XY plane, the gate line and the signal line are provided in the X direction and the Y direction, respectively, via an interlayer insulating film, and a TFT and a comb-like pixel electrode are provided at each intersection. Is provided. The gate electrode constituting the TFT is electrically connected to the gate line, and the source and drain constituting the TFT are electrically connected to the signal line and the pixel electrode, respectively.

  A plurality of common electrodes are formed in an island shape corresponding to each pixel. The TFT, the common electrode, and the pixel electrode have a configuration in which the TFT, the interlayer insulating film, the common electrode, the interlayer insulating film, and the pixel electrode are sequentially stacked from the glass substrate 21 side.

  The common drive line is electrically connected to the common electrode and is formed in the same layer as the signal line, the source, and the drain.

  A plurality of drive lines for the sensor are formed in the X direction in the same layer as the gate electrode and the gate line. The sense sensor drive line is electrically connected to a part of the common electrode, and the common electrode connected to the sense sensor drive electrode functions as a drive electrode of the sense sensor. The sense sensor drive electrode is connected to a touch position detection control circuit (not shown), and the touch position detection control circuit outputs a drive signal for touch position detection.

  A plurality of detection lines for the sensor are formed in the Y direction in the same layer as the source and signal lines. The detection line for the sensor is electrically connected to another common electrode that is not electrically connected to the drive line for the sensor, and the common electrode connected to the detection line for the sensor is used as a detection electrode of the sensor. Function. The sensor sensor drive line is connected to a touch position detection control circuit (not shown), and the touch position detection control circuit receives a detection signal sent from the sensor sensor detection line. Then, the coordinates of the touch position are calculated by analyzing the received detection signal.

In the liquid crystal panel 1, at the display stage, a horizontal electric field is formed by the liquid crystal driving electronic circuit and the liquid crystal 40 is driven to display an image on the liquid crystal panel 1.
In the touch stage, the capacitance between the drive electrode and the detection electrode of the sensing sensor decreases when the finger approaches the display surface. Therefore, the touch position of the finger is detected by detecting the change in the capacitance with the sensing sensor. Is identified.

  The liquid crystal 40 is sandwiched between the color filter substrate 10 and the counter substrate 20. A gap between the two substrates is held by the spacer 41. The two substrates 10 and 20 are layers including a second surface 11b of the glass substrate 11 on which the color filter 15 of the color filter substrate 10 is formed, a sensing sensor electrode of the counter substrate 20, and a liquid crystal driving electronic circuit. It arrange | positions so that the 2nd surface 21b of the glass substrate 21 in which 22 was provided opposes. The liquid crystal 40 is driven by a liquid crystal driving electronic circuit.

  The cover glass 60 is bonded and fixed to the polarizing plate 50 by an adhesive layer (not shown).

  In the liquid crystal panel 1 according to the present embodiment, since the antistatic film 14 of a high resistance sheet in a predetermined range is provided on the color filter substrate 10, it is possible to detect touch during a touch operation and prevent the color filter 15 from being charged. The liquid crystal panel 1 having stable display characteristics can be obtained.

  Further, since the antistatic film 14 is composed of a laminated film of the ITO film 12 and the ST film 13, the ST film 13 suppresses the escape of oxygen from the surface of the ITO film 12, and the sheet resistance of the antistatic film 14 is reduced. Changes with time can be reduced. Therefore, the deterioration of the touch panel function is suppressed, and a liquid crystal panel having a stable touch panel function can be obtained.

[Evaluation of antistatic film]
Next, the evaluation result of the antistatic film formed on the color filter substrate described above will be described. Hereinafter, although it demonstrates using FIGS. 2-6, in any sample board | substrate, the film | membrane formed into a film on the following conditions is used for the ITO film | membrane and ST film | membrane.

The ITO film uses a target made of indium tin oxide (ITO) to which 10% by weight tin oxide (SnO ₂ ) is added, DC sputtering, a substrate temperature of 60 ° C., and an oxygen partial pressure of 0.025 Pa. Film formation was performed in a mixed gas atmosphere.

  The ST film uses a target with silicon (Si) of 12 at% and tin (Sn) of 88 at%, DC sputtering, a substrate temperature of 60 ° C., and a mixed gas atmosphere of argon and oxygen with an oxygen partial pressure of 2.5 Pa. The film was formed.

  The evaluation of the antistatic film was performed by measuring the sheet resistance. The sheet resistance of the transparent conductive film on the sample substrate was measured with a contact resistance measuring device, and the measurement was performed by bringing a needle-like probe into contact with the film surface. In the measurement of the laminated film, the measurement was performed by bringing a probe into contact with the film surface of the laminated film, that is, the ST film surface.

  Hereinafter, evaluation results will be described in order with reference to the drawings.

  FIG. 2 shows a glass substrate with an ITO film single layer (film thickness 10 nm), an ST film single layer (two types of film thickness 45 nm and 60 nm), and a laminated film (ITO film 10 nm) of the ITO film and ST film according to this embodiment. , Shows the change over time in the sheet resistance of the sample substrate on which the ST film (20 nm) is formed. The evaluation was performed at room temperature in the atmosphere.

As an antistatic film of a liquid crystal panel with a horizontal electric field type in-cell type touch panel function, a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ is used to enable touch sensing while maintaining a charge eliminating function. Things are desired. In the figure, a region having a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ is surrounded by a dotted line.

  As shown in FIG. 2, the ITO film single layer shows a desired sheet resistance at the time of film formation, but the sheet resistance is remarkably reduced with the passage of time. In the case of a single ITO film, the sheet resistance tends to decrease with time regardless of the film thickness.

  In the ST film single layer, the sheet resistance tends to increase gradually with time, and deviates from the desired sheet resistance value range.

On the other hand, in the laminated film of the ITO film and the ST film, although the sheet resistance slightly decreases after 12 hours from the film formation, the sheet resistance is almost flat thereafter and the sheet resistance hardly changes immediately after the film formation.
Thus, by forming the ST film on the ITO film, it is possible to reduce the change in sheet resistance with time.

  Next, a case where an antistatic film made of a laminate of an ITO film and an ST film is formed on a glass substrate and a case where it is formed on a color filter substrate will be compared using FIG.

  FIG. 3 shows a sample substrate in which an antistatic film according to the present invention is formed on a glass substrate and a sample substrate in which an antistatic film is formed on the surface of the color filter substrate on which the color filter is not formed, which are left at room temperature in the atmosphere. The change with time of the sheet resistance is shown. Furthermore, in FIG. 3, when a sample substrate having an antistatic film formed on a glass substrate and a sample substrate having an antistatic film formed on a color filter substrate are left in a high temperature and high humidity environment of 60 ° C. and 90% humidity for 120 hours. The sheet resistance value is shown.

As an antistatic film of a liquid crystal panel with a horizontal electric field type in-cell type touch panel function, a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ is used to enable touch sensing while maintaining a charge eliminating function. Things are desired. In the figure, the region where the sheet resistance is 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ corresponds to a region sandwiched between two thick horizontal lines.

  All the sample substrates used a laminated film of an ITO film 10 nm and an ST film 20 nm as an antistatic film.

  As shown in FIG. 3, when the substrate is formed at room temperature in the atmosphere, the sheet resistance of the antistatic film hardly changes over time regardless of whether the substrate on which the antistatic film is formed is a glass substrate or a color filter substrate. It was within the sheet resistance range.

  Further, even when left in a high temperature and high humidity environment for 120 hours, the sheet resistance of the antistatic film was within the range of the sheet resistance value required for the antistatic film, regardless of whether it was a glass substrate or a color filter substrate.

  Thus, it was confirmed that even when an antistatic film is formed on a color filter substrate, an antistatic film with little change in sheet resistance with time can be obtained.

4 to 6 show changes over time in sheet resistance of the antistatic film of a sample substrate prepared by forming an antistatic film on a glass substrate by changing the thickness of each of the ITO film and the ST film. In the figure, the region where the sheet resistance is 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ corresponds to a region sandwiched between two thick horizontal lines.

  FIG. 4 shows the change over time in the sheet resistance of the antistatic film formed with the ST film having a thickness of 55 nm and the ITO film having a thickness of 5 nm, 10 nm, and 20 nm.

  As shown in FIG. 4, the sheet resistance value of the antistatic film having an ITO film of 5 nm is outside the range of the sheet resistance value required for the antistatic film immediately after the film formation, and the desired sheet resistance is maintained even after 60 hours. It was out of the range of values. On the other hand, the sheet resistance value of the antistatic film having the ITO film thickness of 10 nm and 20 nm was within the range of the desired sheet resistance value over time.

  FIG. 5 shows the change over time of the sheet resistance of the antistatic film formed with the ST film having a thickness of 20 nm and the ITO film having a thickness of 5 nm, 10 nm, and 20 nm.

  As shown in FIG. 5, the sheet resistance value of the antistatic film having an ITO film of 5 nm is outside the range of the sheet resistance value required for the antistatic film immediately after the film formation, and the desired sheet resistance is maintained even after 60 hours. It was out of the range of values. On the other hand, the sheet resistance value of the antistatic film having the ITO film thickness of 10 nm and 20 nm was within the range of the desired sheet resistance value over time.

  FIG. 6 shows the change over time of the sheet resistance of the antistatic film formed with the ST film having a thickness of 10 nm and the ITO film having a thickness of 5, 10, and 20 nm.

  As shown in FIG. 6, the sheet resistance value of the antistatic film having an ITO film of 5 nm and 10 nm is outside the range of the sheet resistance value required for the antistatic film immediately after the film formation, and is desired even after 60 hours. It was out of the range of the sheet resistance value. In addition, in the antistatic film having an ITO film thickness of 20 nm, the sheet resistance value is within the desired sheet resistance value range over time, but the sheet resistance is close to the upper limit of the desired sheet resistance value range. Show.

From the results shown in FIGS. 4 to 6, regardless of the thickness of the ST film, the ITO film needs to have a thickness of 10 nm or more, and if it is thinner than this, the sheet resistance value is higher than the desired sheet resistance value. End up.
Moreover, if the film thickness of the ST film is in the range of 20 to 55 nm, the sheet resistance value of the laminated film with the ITO film having the film thickness of 10 to 20 nm falls within the range of the desired sheet resistance value.

  Therefore, in order to obtain sheet resistance and transmittance required for the antistatic film and a barrier function for preventing oxygen loss, it is desirable that the ITO film and ST film constituting the antistatic film have the following film thicknesses.

  It is desirable that the ITO film has a thickness of 10 to 20 nm. If the film thickness is less than 10 nm, the sheet resistance immediately after the film formation becomes higher than the desired resistance value, and a sufficient charge removal function cannot be provided. Further, if the film thickness is thicker than 20 nm, the transmittance is lowered when the ST film is laminated to form an antistatic film.

  The ST film is desirably 20 to 55 nm thick. When the thickness is less than 20 nm, it is not possible to sufficiently obtain a barrier function of suppressing the escape of oxygen from the ITO film. Further, when the film thickness is greater than 55 nm, the transmittance of the ST film alone is lowered. The ST film preferably has a refractive index of 1.6 to 1.8, and the refractive index can be adjusted by the ratio of oxygen introduced during film formation. By using a film having a low refractive index, an antistatic film having a high transmittance can be realized.

[Color filter substrate manufacturing method]
Next, a method for manufacturing the color filter substrate 10 constituting the liquid crystal panel 1 will be described.

  First, a color filter substrate is prepared in which a color filter composed of a black matrix, a red colored layer, a green colored layer, and a blue colored layer is formed on one surface (second surface).

Next, an ITO film is formed on the other surface (first surface) of the color filter substrate where the color filter is not formed.
The ITO film uses a target made of indium tin oxide (ITO) to which 10% by weight tin oxide (SnO ₂ ) is added, and is a magnetron type DC sputtering apparatus. Was used to form a film having a thickness of 10 nm. As the mixed gas of argon and oxygen, a mixed gas having an argon flow rate of 100 sccm, an oxygen flow rate of 5 sccm, and an oxygen partial pressure of 0.025 Pa was used.
In the present embodiment, the target for forming the ITO film is a tin oxide addition amount of 10% by weight, but is not limited thereto. For example, 5 to 10% by weight can be used, and the film thickness range of a suitable ITO film is not significantly affected.

  In this embodiment, in order to obtain an ITO film having a high sheet resistance in a desired range, the film is formed by increasing the oxygen flow rate of the sputtering gas. As the sputtering gas, a mixed gas of argon and oxygen having an oxygen partial pressure of 0.0225 to 0.0325 Pa can be used, whereby an ITO film having a high sheet resistance in a desired range can be obtained.

Next, an ST film is formed on the ITO film.
The ST film is a magnetron-type DC sputtering apparatus using a target of Si at 12 at% and SnO at 88 at%, using a mixed gas of argon and oxygen as a sputtering gas at a substrate temperature of 60 ° C., to a thickness of 20 nm. A film was formed. As the mixed gas of argon and oxygen, a mixed gas having an argon flow rate of 30 sccm, an oxygen flow rate of 500 sccm, and an oxygen partial pressure of 2.5 Pa was used.
In the present embodiment, a target with 12 at% Si is used as the target for forming the ST film. However, the present invention is not limited to this, and the target can be selected up to about 30 at%. The same effect was obtained even when a target with Si of 32 at% was used.

  In this embodiment, in order to obtain an ST film having a high sheet resistance in a desired range and a refractive index of 1.6 to 1.8, the film is formed by adjusting the oxygen flow rate of the sputtering gas. Yes. As the sputtering gas, a mixed gas of argon and oxygen having an oxygen partial pressure of 1.3 to 2.7 Pa can be used, whereby an ST film having a high sheet resistance and a refractive index in a desired range can be obtained.

  In forming the ITO film and the ST film, the film is formed under a temperature condition of 60 ° C. Thereby, deterioration of a color filter with low heat resistance can be prevented.

  As described above, a color filter substrate on which an antistatic film as a transparent conductive film composed of a laminated film of an ITO film and an ST film is formed is manufactured.

As shown in FIG. 5, the antistatic film obtained in this embodiment has a sheet resistance of 5.73 × 10 ⁹ Ω / □ immediately after the film formation, and 2.3 × 10 ⁹ Ω / □ after 12 hours. After 60 hours, it was 1.85 × 10 ⁹ Ω / □, and the change in sheet resistance with time was small.

Here, in the present embodiment, a laminated film of an ITO film and an ST film is used as the antistatic film, but the antistatic film is configured by a single layer film formed by using ITO added with SiO ₂ as a target. It is possible to do. However, in such a film formed by adding Si to ITO, there is a problem in weather resistance and chemical resistance because ITO is exposed on the film surface. In addition, since the target component is directly reflected in the film forming component, it is difficult to adjust the resistance value and transmittance of the antistatic film.

  On the other hand, in this embodiment, since the laminated film of the ITO film and the ST film is adopted as the antistatic film, the ITO film is not exposed. Moreover, since an ITO film and an ST film can be formed using an existing target, manufacturing is easy.

  In the above-described embodiment, the laminated film of the ITO film and the ST film is formed as the antistatic film on the color filter substrate. However, the liquid crystal panel in which the color filter substrate and the counter substrate are bonded in advance and liquid crystal is injected is used. You may form the antistatic film of this invention in a state. Even in this case, the antistatic film can be formed under the same film forming conditions as those for forming the antistatic film on the color filter substrate.

  As described above, in this embodiment, an antistatic film with little change in sheet resistance with time can be obtained by using a laminated film of an ITO film and an ST film as the antistatic film. Therefore, a liquid crystal panel having an in-cell capacitive touch panel function including such an antistatic film has high operation reliability with no deterioration in touch sensitivity and no malfunction due to charging. .

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal panel 10 ... Color filter substrate 11 ... 1st glass substrate 11a ... 1st surface 11b ... 2nd surface 12 ... ITO film 13 ... ST film 14 ... Antistatic film 20 ... Opposite substrate 21 ... 2nd Glass substrate 21a ... 1st surface 21b ... 2nd surface 22 ... Layer provided with the sensor sensor electrode and the electronic circuit for liquid crystal drive 40 ... Liquid crystal

Claims (9)

A substrate having a first surface and a second surface;
A first transparent conductive film made of indium tin oxide provided on the first surface;
A substrate with a transparent conductive film, comprising: a second transparent conductive film containing silicon oxide and tin oxide provided on the first transparent conductive film. The substrate with a transparent conductive film according to claim 1,
The sheet resistance of the laminated film of the first transparent conductive film and the second transparent conductive film is 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □, and the transmittance at a wavelength of 550 nm is 95% or more. With board. The substrate with a transparent conductive film according to claim 1 or 2,
A substrate with a transparent conductive film, wherein a color filter is provided on the second surface. A substrate with a transparent conductive film according to any one of claims 1 to 3,
The first transparent conductive film has a thickness of 10 nm to 20 nm, the second transparent conductive film has a thickness of 20 nm to 55 nm, and the refractive index of the second transparent conductive film is 1 A substrate with a transparent conductive film, which is 6 to 1.8. A first substrate having a first surface and a second surface, a first transparent conductive film made of indium tin oxide provided on the first surface, and provided on the first transparent conductive film A color filter substrate comprising: a laminated film of a second transparent conductive film containing silicon oxide and tin oxide obtained; and a color filter provided on the second surface;
A counter substrate comprising a second substrate, a sensing sensor electrode and a liquid crystal driving electronic circuit provided on one surface of the second substrate;
A liquid crystal that is sandwiched between substrates disposed so that the second surface of the color filter substrate and the one surface of the counter substrate face each other, and that is driven and controlled by the liquid crystal driving electronic circuit. panel. The liquid crystal panel according to claim 5,
A liquid crystal panel, wherein the laminated film of the first transparent conductive film and the second transparent conductive film has a sheet resistance of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω / □ and a transmittance of 95% or more at a wavelength of 550 nm. The liquid crystal panel according to claim 5 or 6,
The first transparent conductive film has a thickness of 10 nm to 20 nm, the second transparent conductive film has a thickness of 20 nm to 55 nm, and the refractive index of the second transparent conductive film is 1 A liquid crystal panel of 6 to 1.8. Using a target made of indium tin oxide on the other surface of the substrate provided with a color filter on one surface, the oxygen partial pressure is 0.0225 to 0.0325 Pa in a mixed gas atmosphere of argon and oxygen. 1 transparent conductive film is formed,
A second transparent conductive film is formed on the first transparent conductive film in a mixed gas atmosphere of argon and oxygen having an oxygen partial pressure of 1.3 to 2.7 Pa using a target made of silicon and tin oxide. Film manufacturing method of substrate with transparent conductive film. It is a manufacturing method of a substrate with a transparent conductive film according to claim 8,
The film formation of the first transparent conductive film and the film formation of the second transparent conductive film are performed at 60 ° C. or less. A method for manufacturing a substrate with a transparent conductive film.

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