Liquid crystal display panel and alkali-free glass substrate

Abstract

To suppress pattern deviation of a liquid crystal display panel.SOLUTION: A liquid crystal display panel of an active matrix drive type includes a substrate of non-alkali glass, a wiring film made of a metal, and an insulating film made of an inorganic material, wherein the wiring film has a thickness of 0.1 μm or more, the insulating film has a thickness of 100 nm or more, the substrate has a long side of 1,800 mm or more, a short side of 1,550 mm or more, and a thickness of 0.5 mm or less, and the metal has a product of a Young's modulus and a thermal expansion coefficient at room temperature of 10,000 * 10-7 GPa / °C. to 25,000 * 10-7 GPa / °C. The inorganic material has a smaller average thermal expansion coefficient (50°C to 350°C) than that of the non-alkali glass, and the non-alkali glass has a Young's modulus (E) of 70 to 95 GPa, an average thermal expansion coefficient (α) of 30°C to 45°C of 32 * 10 -7 to 44 * 10 -7 (1 / °C), and a predetermined composition.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal display panel, and more particularly to a liquid crystal display panel having a pixel array formed on a substrate made of a predetermined alkali-free glass. [Background technology]

[0002] In recent years, as liquid crystal display panels have become larger and higher definition, suppressing pattern misalignment of pixel arrays due to heat treatment during the manufacturing process has become one of the most important issues. Due to the demand for higher definition, the metal wiring of semiconductor element arrays formed on substrates has become thinner, and the tolerance for pattern misalignment has become increasingly smaller.

[0003] Pattern misalignment is thought to be caused by thermal contraction due to structural relaxation of the glass substrate during the manufacturing process of the liquid crystal display panel. The first method proposed to suppress this is to reduce the average thermal expansion coefficient of the glass. For this method, a glass with an average thermal expansion coefficient of 25×10 between 30 and 380°C is used. -7 ~36×10 -7 / °C (Patent Document 1), and an average thermal expansion coefficient of 30×10 -7 ~43×10 -7 / °C has been proposed (Patent Document 2). Glass with an average thermal expansion coefficient close to that of a-Si, p-Si, etc., which are formed on glass substrates has also been proposed (Patent Document 3).

[0004] The second method is to increase the strain point of the glass. Patent Document 1 proposes setting the strain point at 640°C or higher, Patent Document 2 proposes setting it at 710°C or higher but lower than 725°C, and Patent Document 3 proposes setting it at 680°C or higher but lower than 740°C.

[0005] Other proposals include lowering the density of the glass to suppress bending of the glass (Patent Documents 1 and 2) and increasing the Young's modulus (Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2002-308643 [Patent Document 2] International Publication No. 2013 / 161902 [Patent Document 3] Japanese Patent Publication No. 2014-118313 Summary of the Invention [Problem to be solved by the invention]

[0007] However, it is difficult to explain pattern misalignment due to the influence of structural relaxation of glass when the maximum temperature of heat treatment in the manufacturing process is relatively low, around 200 to 450° C. In fact, lowering the average thermal expansion coefficient of the substrate glass may actually increase pattern misalignment.

[0008] In view of the above circumstances, an object of the present invention is to suppress pattern misalignment in large-sized liquid crystal display panels, the maximum temperature of which is relatively low in the manufacturing process. [Means for solving the problem]

[0009] The present invention provides an active matrix drive type liquid crystal display panel, which is manufactured by a manufacturing process including the steps of forming a metal film on at least one surface of an alkali-free glass substrate, patterning the resulting metal film to form a wiring film, and then forming a gate insulating film made of an inorganic material, and at least one surface of the alkali-free glass substrate is provided with the metal wiring film and the inorganic insulating film. That is, the present invention provides a semiconductor device comprising a substrate made of alkali-free glass, a wiring film made of metal, and an insulating film made of an inorganic substance formed on the surface of the wiring film, The wiring film has a thickness of 0.1 μm or more, The insulating film has a thickness of 100 nm or more, The substrate has a long side of 1800 mm or more, a short side of 1500 mm or more, and a thickness of 0.5 mm or less, The product of the Young's modulus and the thermal expansion coefficient of the metal at room temperature is 10,000 x 10 -7 GPa / ℃~25,000×10 -7 GPa / ℃, the inorganic material has an average thermal expansion coefficient (50°C to 350°C) smaller than that of the alkali-free glass; The alkali-free glass has a Young's modulus (E) of 70 to 95 GPa and an average thermal expansion coefficient (α) of 32 × 10 -7 ~45×10 -7 (1 / °C), and satisfies the following formula (1): 20α+7E≧1310 (1), In formula (1), the unit of α is 10 -7 (1 / ℃), E is in GPa, and, It has the following composition in mole percent on an oxide basis: SiO266~74, Al2O310~15, B2O30.1~5, MgO 2-12, CaO 3-11, SrO 0-10, BaO 0-5, ZrO20~2, Preferably, it has the following composition in mole percent on an oxide basis: SiO266~74, Al2O310~15, B2O3 0.1 to less than 3.0 MgO 2-10, CaO 3-11, SrO 0.1-10, BaO 0-5, ZrO20~2, It is a liquid crystal display panel. In yet another preferred example, the alkali-free glass has the following composition expressed in mole percent on an oxide basis: SiO268.0~74, Al2O310~15, B2O30.1~5, MgO 2~9.0, CaO 3-11, SrO 0-10, BaO 0-1, ZrO20~2, MgO+CaO+SrO+BaO: 18 or less. [Effects of the Invention]

[0010] After extensive investigation, the inventors discovered that in large-scale liquid crystal display panels in which the maximum heat treatment temperature in the manufacturing process is relatively low (for example, 450°C or less), the influence of the combination of the metal wiring film and the dielectric insulating film with the substrate glass cannot be ignored. While not intended to limit the scope of the present invention, when the maximum heat treatment temperature in the manufacturing process is relatively low, it is believed that warping of the glass substrate, rather than structural relaxation as has been considered in the past, is the major cause of pattern misalignment. In the liquid crystal display panel of the present invention, pattern misalignment is significantly suppressed by using a predetermined combination of the glass constituting the substrate, the metal constituting the wiring, the dielectric constituting the insulating film, and the design of the display panel. [Brief explanation of the drawings]

[0011] [Figure 1] 1(a) to 1(c) are diagrams showing the deformed state of the glass substrate in Example 1, with FIG. 1(b) showing the deformed state in step 1, FIG. 1(a) showing the deformed state in step 2, and FIG. 1(c) showing the deformed state in step 3. [Figure 2] FIG. 2 is a graph plotting a simulation of the warpage of a substrate when a copper pattern having a predetermined thickness and a silicon nitride film having a predetermined thickness covering the copper pattern are formed on the glass prepared in the examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] First, we will explain the alkali-free glass that constitutes the glass substrate of the liquid crystal display panel of the present invention. In the present invention, "alkali-free" glass means glass that is substantially free of alkali metal oxides such as Na2O and K2O. Here, "substantially free" means that it is free except for unavoidable impurities (the same applies hereinafter). In the present invention, the amount of alkali metal that is unavoidably contained is at most about 0.1 mol %.

[0013] The alkali-free glass contains SiO2 and Al2O3, which form the skeleton of the glass, as well as a predetermined amount of alkaline earth metal oxides. First, the content of each of these components on an oxide basis will be explained. In the following, unless otherwise specified, "%" means "mol %."

[0014] If the SiO2 content is less than 66%, the strain point is not high enough, and the thermal expansion coefficient and specific gravity tend to be too high. Therefore, the SiO2 content is 66% or more, preferably 66.5% or more. On the other hand, if the content exceeds 74%, the glass viscosity will be 10 2 The solubility tends to deteriorate, the devitrification temperature rises, and the Young's modulus decreases, for example, the temperature (T2) at which the poise becomes high (dPa·s). Therefore, the SiO2 content is 74% or less, preferably 73% or less, more preferably 72% or less, and even more preferably 71% or less.

[0015] Al2O3 has the effects of suppressing phase separation, improving the strain point, and increasing Young's modulus, but if its content is less than 10%, it is difficult to fully obtain these effects. Therefore, the Al2O3 content is 10% or more, preferably 11% or more, and more preferably 12% or more. On the other hand, if the content exceeds 15%, T2 increases, the solubility deteriorates, and the devitrification temperature also tends to increase. Therefore, the Al2O3 content is 15% or less, preferably 14% or less, and more preferably 13% or less.

[0016] B2O3 is an essential component that improves the meltability of glass and lowers the devitrification temperature. However, if its content exceeds 5%, the Young's modulus tends to decrease excessively and the thermal expansion coefficient tends to become too low. Therefore, the B2O3 content is 5% or less, preferably 4% or less, even less than 3%, more preferably 2.7% or less, even more preferably 2.5% or less, even more preferably 2.0% or less, and particularly preferably 1.5% or less. On the other hand, if the content is less than 0.1%, the meltability deteriorates, making it difficult to obtain a homogeneous glass. Therefore, the B2O3 content is 0.1% or more, preferably 0.2% or more, more preferably 0.3% or more, and even more preferably 0.5% or more.

[0017] MgO has the effect of improving solubility and reducing specific gravity without excessively increasing the thermal expansion coefficient and significantly lowering the strain point, but if its content is less than 2%, these effects cannot be fully achieved. Therefore, the MgO content is 2% or more, preferably 3% or more, and more preferably 4% or more. On the other hand, if the content exceeds 12%, the devitrification temperature becomes high. Therefore, the MgO content is 12% or less, preferably 10% or less, more preferably 9.5% or less, and even more preferably 9% or less.

[0018] CaO also has the effect of improving solubility, increasing Young's modulus, and lowering devitrification temperature without excessively increasing the thermal expansion coefficient or significantly lowering the strain point. If the CaO content is less than 3%, these effects cannot be fully achieved. The CaO content is 3% or more, preferably 4% or more, and more preferably 5% or more. On the other hand, if the CaO content exceeds 11%, the devitrification temperature will be high and the amount of phosphorus, an impurity in limestone (CaCO3), the raw material for CaO, may increase. Therefore, the CaO content is 11% or less, preferably 10% or less, more preferably 9% or less, and even more preferably 8% or less.

[0019] Although SrO is not an essential component, it has the effect of improving solubility without increasing the devitrification temperature. Furthermore, to obtain the effect of relatively increasing the thermal expansion coefficient, the SrO content is preferably 0.1% or more, more preferably 1% or more, and even more preferably 2% or more. On the other hand, if the SrO content exceeds 10%, the specific gravity and thermal expansion coefficient tend to become too high. Therefore, the SrO content is 10% or less, preferably 8% or less, more preferably 7% or less, and even more preferably 6% or less.

[0020] Although BaO is not an essential component, it has the effect of improving solubility and devitrification resistance, so it may be contained in an amount of 5% or less. However, if it exceeds this amount, the density tends to increase. It is preferably 4.5% or less, more preferably 4% or less, even more preferably 1% or less, particularly preferably 0.5% or less, and most preferably not contained at all.

[0021] ZrO2 is not an essential component, but it has the effect of lowering the melting temperature and promoting crystal precipitation during firing, so it may be contained in an amount of 2% or less. If the amount exceeds this amount, the devitrification resistance of the glass decreases and the relative dielectric constant (ε) tends to increase. The content is preferably 1.5% or less, more preferably 1% or less, even more preferably 0.5% or less, and most preferably substantially none.

[0022] In the alkali-free glass of the present invention, if the total amount (mol %) of alkaline earth metal oxides, i.e., MgO, CaO, SrO, and BaO, is less than 15%, the Young's modulus tends to be low and the solubility tends to be poor. Therefore, the total is preferably 15% or more, more preferably 16% or more, and even more preferably 17% or more. On the other hand, if the total exceeds 21%, the thermal expansion coefficient tends to be too high. It is preferably 20% or less, more preferably 19% or less, and even more preferably 18% or less.

[0023] Furthermore, it is preferable that the content of MgO and other alkaline earth metals satisfy the following three conditions. This makes it possible to increase the strain point without increasing the devitrification temperature, and further to improve the viscosity of the glass, particularly the glass viscosity, by 10.4 The temperature T4 at which the viscosity becomes dPa·s can be lowered. MgO / (MgO+CaO+SrO+BaO) is preferably 0.20 or more, more preferably 0.25 or more, even more preferably 0.3 or more, particularly preferably 0.4 or more, and most preferably 0.45 or more. MgO / (MgO+CaO) is 0.3 or more, more preferably 0.4 or more, even more preferably 0.52 or more, particularly preferably 0.55 or more, and most preferably 0.6 or more. MgO / (MgO+SrO) is 0.6 or more, more preferably 0.63 or more, and even more preferably 0.65 or more.

[0024] Also, Al2O3 × (MgO / (MgO + CaO + SrO + BaO)) is preferably 5.5 or more. If this ratio is less than 5.5, the Young's modulus tends to be low. It is more preferably 5.75 or more, even more preferably 6 or more, and most preferably 6.25 or more.

[0025] It has been discovered that the alkali-free glass of the present invention has a thermal expansion coefficient and Young's modulus that fall within ranges suitable for suppressing warpage when the relationship between the components, specifically the composition expressed in mole percent on an oxide basis, is 759 - 13.1 × SiO2 - 7.5 × Al2O3 - 15.5 × B2O3 + 9.7 × MgO + 21.8 × CaO + 27.2 × SrO + 27.9 × BaO ≧ 0.

[0026] In addition to the above components, the glass may contain ZnO, Fe2O3, SO3, F, Cl, and SnO2 in a total amount of 2% or less, preferably 1% or less, and more preferably 0.5% or less, which have the effect of improving the melting property, clarification, formability, etc. of the glass.

[0027] On the other hand, the glass preferably contains substantially no P2O5 to prevent deterioration of the properties of a thin film of metal or oxide, etc., formed on the surface of the glass sheet.Furthermore, to facilitate recycling of the glass, the glass preferably contains substantially no PbO, As2O3, or Sb2O3.

[0028] Next, various properties of the alkali-free glass will be described. The glass has an average thermal expansion coefficient (α) of 45×10 at 50 to 350°C. -7 / °C or less. This provides high thermal shock resistance and increases productivity during panel manufacturing. -7 / °C or less, and more preferably 41 × 10 -7 / °C or less, more preferably 40 × 10 -7 On the other hand, if α is too small, warping during film formation increases. -7 / ℃ or more. 33×10 -7 / ℃ or more is preferable, 35 × 10 -7 / °C or more is more preferable.

[0029] The glass has a Young's modulus (E) of 70 GPa or more. Such a high Young's modulus gives the glass high fracture toughness, making it suitable for use as a substrate for large displays. It is preferably 75 GPa or more, more preferably 78 GPa or more, even more preferably 80 GPa or more, and particularly preferably 83 GPa or more. On the other hand, if the Young's modulus is too high, the cuttability of the glass deteriorates, so it is 95 GPa or less. It is preferably 90 GPa or less, more preferably 88 GPa or less.

[0030] The above α and E satisfy the following formula (1). 20α+7E≧1310 (1) where α is in units of 10 -7 The unit of E is GPa. When the above formula (1) is satisfied, warping due to heating is small even for large substrates.

[0031] Preferably, the glass has a viscosity η of 10 2 The temperature T2 at which the poise (dPa·s) is reached is 1710°C or lower, which allows for relatively easy melting. It is more preferably lower than 1710°C, even more preferably 1700°C or lower, and even more preferably 1690°C or lower.

[0032] Preferably, the glass has a viscosity η of 10 4The poise temperature T4 is 1320°C or lower, which is suitable for float forming, more preferably 1315°C or lower, even more preferably 1310°C or lower, and even more preferably 1305°C or lower.

[0033] Preferably, the glass has a strain point of 680°C or higher, more preferably 710°C or higher, and even more preferably 730°C or higher. For the same reasons as for the strain point, the glass preferably has a glass transition point of 760° C. or higher, more preferably 770° C. or higher, and even more preferably 780° C. or higher.

[0034] Preferably, the glass has a specific gravity of 2.65 or less, more preferably 2.64 or less, and even more preferably 2.62 or less.

[0035] Preferably, the glass has a devitrification temperature of 1350°C or lower, which makes it easier to form by the float process. It is more preferably 1340°C or lower, and even more preferably 1330°C or lower. The devitrification temperature in the present invention is the temperature at which crystals precipitate on the surface and inside of the glass when observed with an optical microscope after heat treatment when crushed glass particles are placed in a platinum dish and heat treated for 17 hours in an electric furnace controlled at a constant temperature.

[0036] Preferably, the glass has a photoelastic constant of 31 nm / MPa / cm or less. Stress generated during the manufacturing process of a liquid crystal display panel or during use of a liquid crystal display device can cause the glass substrate to have birefringence, resulting in a gray display instead of a black image, and a decrease in the contrast of the liquid crystal display. This phenomenon can be suppressed by setting the photoelastic constant to 31 nm / MPa / cm or less. It is more preferably 30 nm / MPa / cm or less, even more preferably 29 nm / MPa / cm or less, even more preferably 28.5 nm / MPa / cm or less, and particularly preferably 28 nm / MPa / cm or less. Furthermore, taking into consideration the ease of ensuring other physical properties, the glass preferably has a photoelastic constant of 23 nm / MPa / cm or more, more preferably 25 nm / MPa / cm or more. The photoelastic constant can be measured by a disk compression method.

[0037] Preferably, the glass has a dielectric constant of 5.6 or higher. In the case of an in-cell touch panel (a liquid crystal display panel with a built-in touch sensor) as described in JP 2011-70092 A, a high dielectric constant for the glass substrate is preferable from the viewpoints of improving the sensing sensitivity of the touch sensor, reducing the driving voltage, and saving power. A dielectric constant of 5.6 or higher improves the sensing sensitivity of the touch sensor. A dielectric constant of 5.8 or higher is more preferable, and 6.0 or higher is even more preferable. Furthermore, in consideration of preventing degradation of image display quality (crosstalk), increased power consumption, and difficulty in achieving high resolution on the liquid crystal display, the dielectric constant is preferably 7.5 or less, more preferably 7 or less, and even more preferably 6.5 or less. The dielectric constant can be measured by the method described in JIS C-2141.

[0038] The liquid crystal display panel of the present invention is an active matrix drive panel comprising switching elements such as TFTs on a substrate made of the alkali-free glass. The substrate has long sides of 1800 mm or more and short sides of 1500 mm or more. Preferably, the long sides are 2100 mm or more and short sides are 1800 mm or more. More preferably, the long sides are 2400 mm or more and short sides are 2100 mm or more. The substrate also has a thickness of 0.5 mm or less, preferably 0.4 mm or less, and even more preferably 0.3 mm or less. There are no particular limitations on the upper limits of each side or the lower limits of the thickness of the substrate, but for example, the long sides are 3200 mm or less, the short sides are 2900 mm or less, and the plate thickness is 0.05 mm or more.

[0039] The substrate has a wiring film made of metal and an insulating film made of inorganic material on at least one surface thereof. The present invention suppresses pattern misalignment by combining the properties of these films with the alkali-free glass.

[0040] The wiring film constitutes a circuit pattern including gate electrodes, gate bus lines, auxiliary capacitance lines, auxiliary capacitance electrodes, etc. The wiring film has a thickness of 0.1 μm or more. There is no particular upper limit to the thickness, but in practice it is about 0.3 to 0.6 μm. With this thickness, it is possible to form gate bus lines as thin lines with widths of about 4 to 10 μm.

[0041] The product of the Young's modulus and the thermal expansion coefficient of the metal at room temperature is 10,000 x 10 -7 GPa / ℃~25,000×10 -7 GPa / ℃, preferably 10,000×10 -7 GPa / ℃~24,000×10 -7 GPa / ℃, more preferably 10,000×10 -7 GPa / ℃~22,000×10 -7 GPa / ° C. If the product is outside the above range, warping of the glass substrate after the wiring film is formed tends to increase.

[0042] Examples of the metal include copper, aluminum, molybdenum, titanium, chromium, tantalum, tungsten, and alloys thereof. The gate electrode may have a structure in which these metals are stacked. Preferably, copper, aluminum, molybdenum, or alloys thereof is used, and more preferably, copper, aluminum, or molybdenum is used. The products of Young's modulus and thermal expansion coefficient at room temperature for these metals are as follows: Copper: 21,000~23,000×10 -7 GPa / ℃ Aluminum: 16,000~17,000×10 -7 GPa / ℃ Molybdenum: 15,000~17,000×10 -7 GPa / ℃

[0043] The substrate is provided with an insulating film made of an inorganic material that covers the circuit pattern. The insulating film has a thickness of 100 nm or more. There is no particular upper limit to the thickness, but in practice it is about 300 to 400 nm.

[0044] The inorganic substance has an average thermal expansion coefficient (α) of the alkali-free glass, i.e., 32×10 -7 ~45×10 -7 / °C, and have a smaller average thermal expansion coefficient (50 to 350°C). Examples of such inorganic materials include silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, and aluminum oxynitride, which may be in a single layer or laminate structure. Silicon nitride, silicon oxide, or silicon oxynitride is preferably used. The average thermal expansion coefficients of these materials are, for example, as shown below. Silicon nitride: 32×10 -7 / ℃ Silicon oxide: 5.5×10 -7 / ℃ The thermal expansion coefficient of silicon oxynitride is considered to be somewhere between the above values ​​depending on the oxygen / nitrogen ratio.

[0045] It is known that film stress can be changed by controlling the film formation conditions, and by changing the film stress, it is possible to appropriately reduce the warpage of the glass substrate. However, in the case of a metal film for a gate electrode, the applied output during film formation becomes too large, increasing the possibility of abnormal discharge. In addition, in the case of a gate insulating film, hydrogen addition or the like can be used, but this may not result in a transistor with the desired characteristics. Therefore, when there are constraints on the film formation conditions or when further suppression of warpage is desired, the application of a specific glass substrate of the present invention makes it possible to effectively suppress warpage.

[0046] As liquid crystal display panels become more precise, the metal wiring film becomes thinner, resulting in a thicker metal wiring film to maintain resistance. A circuit pattern of the metal wiring film is formed on a glass substrate, and an insulating film is formed over almost the entire surface of the glass substrate, covering the spaces between and above the wiring. It has been discovered that, due to differences in the thermal expansion coefficients and Young's moduli of the glass substrate, the thickened metal wiring film, and the insulating film, warping occurs when the glass substrate, metal wiring film, and insulating film are integrated together during heat treatment in the manufacturing process. It has been found that warping is particularly likely to be significant when the circuit pattern of the metal wiring film is biased primarily vertically or horizontally. When warping occurs in the glass substrate, it is easy for the wiring and elements to deviate from their originally designed positions.

[0047] A TFT active layer, a passivation film, a planarization film, and other layers are provided on the insulating film to form a TFT substrate. The TFT substrate can be manufactured using a known manufacturing process, for example, with a maximum temperature of 450°C or less. This maximum temperature is typically the maximum temperature during the process of forming the TFT active layer. Depending on the type of semiconductor used and the process, the maximum temperature may be more preferably 400°C or less, even more preferably 370°C or less, and even more preferably 350°C or less. Considering the manufacturing process and the stability of TFT performance, the maximum temperature is preferably 200°C or more, more preferably 250°C or more, and even more preferably 300°C or more. Examples of semiconductors for such active layers include amorphous silicon (a-Si) and indium-gallium-zinc oxide semiconductors. The TFT may be a bottom-gate (inverse staggered) or top-gate (staggered) type. However, to fully utilize the effects of the present invention, an inverse staggered type is preferred, as it often involves forming a metal film and an insulating film early in the TFT manufacturing process. Known materials may be used for the passivation film, planarization film, and the like. That is, the liquid crystal display panel of the present invention is an active-matrix-driven liquid crystal display panel manufactured by a manufacturing process including the steps of forming a metal film on at least one surface of an alkali-free glass substrate, such as an amorphous silicon (a-Si) or indium-gallium-zinc oxide semiconductor, patterning the metal film to form a wiring film, and then forming a gate insulating film made of an inorganic material. That is, unlike manufacturing processes that involve high-temperature heat treatment such as LTPS, the maximum temperature in the manufacturing process of the liquid crystal display panel of the present invention (a liquid crystal display panel using amorphous silicon (a-Si) or an indium-gallium-zinc oxide semiconductor as TFTs) is a low-temperature heat treatment temperature, for example, 450°C or less. At least one surface of the alkali-free glass substrate is provided with the metal wiring film and the inorganic insulating film.

[0048] The TFT substrate is combined with a color filter substrate, liquid crystal molecules, a sealant, a polarizing plate, a light guide plate, various optical films, a backlight, etc. to form a liquid crystal display panel. The size of the display is appropriately selected depending on the application, and examples include panels for mobile displays with a diagonal length of approximately 3 to 10 inches, and 4K television displays with a diagonal length of 30 to 70 inches. For displays with a resolution of 30 inches or larger, the resolution is preferably 100 pixels per inch (hereinafter referred to as ppi) or higher, more preferably 150 ppi or higher, and even more preferably 200 ppi or higher. For mobile display applications, the resolution is preferably 300 ppi or higher, more preferably 400 ppi or higher, and even more preferably 500 ppi or higher. [Example]

[0049] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0050] The raw materials for each component were mixed so that the glass composition would be the target glass composition (unit: mol%) shown in Table 1, and melted in a platinum crucible at a temperature of 1500 to 1600°C. During melting, the glass was homogenized by stirring using a platinum stirrer. The molten glass was then poured out, formed into a plate, and slowly cooled. Various evaluations were carried out using this glass plate. In Table 1, Examples 1 to 4 and 7 to 12 are glasses that are examples of the present invention, and Examples 5 and 6 are glasses for comparison. The values ​​in parentheses indicate calculated values.

[0051] Table 1 shows the glass composition (unit: mol%) and the average thermal expansion coefficient (unit: × 10) at 50 to 300°C. -7 / °C), strain point (unit: °C), glass transition point (unit: °C), specific gravity (unit: g / cm 3 ), Young's modulus (GPa) (measured by ultrasonic method), and the temperature T2 (when the glass viscosity η is 10 2 dPa·s, unit: °C), and the temperature T4 (when the glass viscosity η is 10 4The table shows the temperature at which the viscosity becomes dPa·s (unit: °C), the devitrification temperature (unit: °C), the photoelastic constant (unit: nm / MPa / cm) (measured by the disk compression method), and the relative dielectric constant (measured by the method specified in JIS C-2141).

[0052] [Table 1]

[0053] To confirm the effects of the present invention, the deformation of a glass substrate was calculated using the finite element method. The calculation software used was MSC's MARC, and the calculation was performed using the following procedure. First, in step 1, the glass of Example 1 was used as a substrate with a substrate size of G6 (longer side 1800 mm, shorter side 1500 mm) and a thickness of 0.5 mm. A 200 nm-thick copper film was coated on the substrate at 200°C, and the substrate deformation was calculated when the substrate was cooled to room temperature (20°C). Next, in step 2, to simulate patterning with a width of 7 μm and a pitch of 70 μm, the substrate deformation was calculated when the copper film was anisotropic at room temperature, such that the Young's modulus in the edge axis direction was 1 / 10 of that in the long axis direction of the substrate. Furthermore, in step 3, the substrate to which the anisotropy was imparted in step 2 was heated to 200°C, and the silicon nitride film was coated with a thickness of 200 nm and the substrate was cooled to room temperature (20°C). The product of Young's modulus and thermal expansion coefficient of copper at room temperature in copper film is 21,000 x 10 -7 ~23,000×10 -7 GPa / ℃. The average thermal expansion coefficient of silicon nitride (50 to 350℃) is 32×10 -7 / °C, which is smaller than the average thermal expansion coefficient of glass. Figures 1(a) to 1(c) show the glass of Example 1 (Young's modulus 84 GPa, thermal expansion coefficient 39 × 10 -7 The calculation results for a substrate with a temperature of 1000 K ( / °C) are shown as contour diagrams. In step 1 (Fig. 1(b)), concentric deformation occurs due to the isotropic film, but in step 2 (Fig. 1(a)), saddle-shaped deformation is observed due to the anisotropy of the copper film. Furthermore, in step 3 (Fig. 1(c)), it was found that the deformation was reduced compared to step 2.

[0054] FIG. 2 shows the maximum warpage of the substrate after the silicon nitride film deposition, calculated using the method described above, assuming that the glasses of Examples 1 to 12 were used as glass substrates with a substrate size of G6 (longer side 1800 mm, shorter side 1500 mm) and a thickness of 0.5 mm, and that a copper pattern equivalent to a 200 nm film thickness, 7 μm width, and 70 μm pitch parallel to one direction was formed thereon, and a 200 nm thick silicon nitride film was formed covering the copper pattern over the entire glass substrate. In the figure, the warpage decreases toward the upper right and increases toward the lower left. The upper right portion of the straight line corresponds to the part corresponding to 20α + 7E ≧ 1300. As can be seen from the figure, the glasses of Examples 1 to 4 and 7 to 12, which satisfy the requirements of the present invention, exhibited small warpage and were less likely to cause pattern misalignment. On the other hand, Examples 5 and 6, which do not satisfy the glass composition and formula (1), exhibited large warpage and are likely to result in significant pattern misalignment.

[0055] Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2014-241601) filed on November 28, 2014, the contents of which are incorporated herein by reference. [Industrial Applicability]

[0056] In the liquid crystal display panel of the present invention, pattern misalignment is significantly suppressed by a predetermined combination of the substrate glass, wiring metal, dielectric, and display panel design.

Claims

1. An active matrix driven liquid crystal display panel, The liquid crystal display panel comprises an alkali-free glass substrate; a wiring film made of metal formed on at least one surface of the alkali-free glass substrate; an insulating film made of an inorganic material formed on the surface of the wiring film; The wiring film has a thickness of 0.1 μm or more, The insulating film has a thickness of 100 nm or more, The substrate has a long side of 1800 mm or more, a short side of 1500 mm or more, and a thickness of 0.5 mm or less, The metal has a Young's modulus and thermal expansion coefficient product of 10,000×10 at room temperature. －７ GPa / ℃~25,000×10 －７ GPa / °C, the inorganic material has an average thermal expansion coefficient (50°C to 350°C) smaller than that of the alkali-free glass; The alkali-free glass has a Young's modulus (E) of 70 to 95 GPa and an average thermal expansion coefficient (α) of 32×10 at 50°C to 350°C. －７ ~45 x 10 －７ (1 / °C), and satisfies the following formula (1): 20α+7E≧1310 (1), In formula (1), the unit of α is 10 －７ (1 / °C), E is in GPa, and, It has the following composition in mole percent on an oxide basis: Yes ２ 68.0~74, Al ２ O ３ 12-15 B ２ O ３ 2.0~5、 MgO 2-9.0, CaO 3-11, SrO 0-10, BaO >0~1, ZrO ２ 0~2、 MgO+CaO+SrO+BaO: 16 or less, MgO / (MgO+CaO): 0.27 to 0.50, LCD display panel.

2. The alkali-free glass has a composition expressed in mole percent on an oxide basis of 759-13.1×SiO ２ -7.5 x Al ２ O ３ -15.5 x B ２ O ３ 2. The liquid crystal display panel of claim 1, wherein the relationship: +9.7*MgO+21.8*CaO+27.2*SrO+27.9*BaO≥0 is satisfied.

3. 3. The liquid crystal display panel according to claim 1, wherein the metal is copper, aluminum, or molybdenum.

4. 4. The liquid crystal display panel according to claim 1, wherein the inorganic material is silicon nitride, silicon oxynitride or silicon oxide.

5. 5. The liquid crystal display panel according to claim 1, wherein the maximum temperature in the manufacturing process of the liquid crystal display panel is 450[deg.] C. or less.

6. In mole percent based on oxides, Yes ２ 68.0~74, Al ２ O ３ 12-15 B ２ O ３ 2.0~5、 MgO 2-9.0, CaO 3-11, SrO 0-10, BaO >0~1, ZrO ２ 0~2、 MgO+CaO+SrO+BaO: 16 or less, MgO / (MgO+CaO): 0.27 to 0.50, Young's modulus (E) is 70 to 95 GPa, and the average thermal expansion coefficient (α) at ​​50°C to 350°C is 32 x 10 －７ ~45 x 10 －７ (1 / °C), and satisfies the following formula (1): 20α+7E≧1310 (1), In formula (1), the unit of α is 10 －７ (1 / °C), E is in GPa, non-alkali glass substrate.

7. The alkali-free glass substrate has a composition expressed in mole percent on an oxide basis of 759-13.1×SiO ２ -7.5 x Al ２ O ３ -15.5 x B ２ O ３ The alkali-free glass substrate according to claim 6, which satisfies the relationship: +9.7×MgO+21.8×CaO+27.2×SrO+27.9×BaO≧0.

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