WO2007069729A1 - Front glass substrate for plasma display and plasma display apparatus - Google Patents

Abstract

Disclosed is a front glass substrate for use in a plasma display, which comprises 100 wt% of a base glass composition and 0.25 to 0.80 wt% of an iron oxide component as a coloring ingredient, wherein the base glass composition consists of 60-70 wt% of SiO2, 0.5-5 wt% of Al2O3, 2-6 wt% of Na2O, 8-16 wt% of K2O, 10-20 wt% of Na2O+K2O, 8-15 wt% of MgO, 0-6 wt% of CaO, 0-5 wt% of SrO, 0-5 wt% of BaO, 10-20 wt% of MgO+CaO+SrO+BaO and 0.5-5 wt% of ZrO2, and the ratio of the weight of a bivalent iron oxide to the total weight of the iron oxide component (the weight of a bivalent iron oxide/the total weight of the iron oxide component) is 0.25 to 0.55.

Description

 Specification

 Front glass substrate for plasma display and plasma display device

 [0001] The present invention has a near-infrared absorbing ability, an excellent light transmission performance in the visible wavelength region of 380 to 770 nm, particularly 380 to 480 nm, and further has heat resistance and an appropriate thermal expansion coefficient. The present invention relates to a front glass substrate for plasma display and a plasma display device using the same.

 Background of the Invention

 A plasma display panel (hereinafter referred to as PDP) has a structure in which a discharge gas such as helium-xenon is enclosed in a discharge space formed between a pair of glass substrates. An electrode is formed on each substrate, and a discharge of the above-mentioned sealed gas in a desired discharge cell is generated by applying a predetermined voltage between the predetermined electrodes. The ultraviolet rays generated by this discharge excite the phosphor formed in the discharge cell, and the visible light emitted from the excited phosphor constitutes the image display of the PDP.

 [0003] Particularly in the case of a color display PDP, color display is realized by forming a phosphor layer of red, green, or blue in each discharge cell. At this time, the emission wavelengths of the red, green, and blue phosphors are red: 620 nm, green: 550 nm, and blue: 460 nm. As described above, in the PDP, the discharge state of the discharge cell is controlled, the ultraviolet rays generated during the discharge are converted into visible light by the phosphor, and the desired image is displayed by transmitting the light through the front glass substrate force. .

 [0004] However, when a plasma discharge is performed using a gas such as neon-xenon gas as the discharge gas, powerful near-infrared rays are emitted in the forward direction of the PDP. This near-infrared ray has no effect on the image display, but it is close to the center wavelength of the emission spectrum characteristics of light-emitting diodes (hereinafter referred to as LEDs) used in remote controller devices that are popular today. Therefore, the operation of the remote controller device using such an LED is disturbed and the device receiving the signal of the remote controller device malfunctions.

[0005] The remote controller device and the device on the receiving side thereof are used to operate the PDP device itself. Forces not only related to the near infrared rays, but also other devices installed around the PDP device, such as video tape recorders and air conditioners There can be enough. Furthermore, near infrared rays are inevitably adversely affected by devices other than those using LEDs.

 [0006] For these reasons, it has been proposed to add near-infrared absorption by adding iron oxide or the like (see, for example, Patent Document 1).

 [0007] Furthermore, in the PDP device, when a phosphor emits light, a part of the phosphor is scattered on the inner surface of the front glass substrate, and reflection is repeated on the inner and outer surfaces of the glass substrate, thereby causing adjacent pixels across the partition to pass through. A phenomenon (blurring) occurs in which the video is blurred. In order to suppress this phenomenon, NiO, CoO and Nd 2 O have the ability to absorb light in the visible light range.

 A glass substrate has been proposed that has 2 3 and the like and absorbs light before adjoining adjacent pixels (see, for example, Patent Documents 2 and 3).

 Patent Document 1: JP 2001-139342 A

 Patent Document 2: Japanese Patent Laid-Open No. 11-1342

 Patent Document 3: Japanese Patent Laid-Open No. 11 171587

 Summary of the Invention

 [0008] However, acid pig iron contains both divalent and trivalent iron in glass, and divalent iron oxide absorbs infrared rays but does not absorb light in the visible wavelength region, so there is no problem. However, trivalent iron oxide has the problem of absorbing light in the visible wavelength region. For example, in the composition described in JP-A-2001-139342, the light transmittance of 380 to 480 nm is low.

 [0009] Since the light of 380 to 480 nm contains the blue emission wavelength of 460 nm of the phosphor, the luminance of the blue light emitted by the phosphor is lowered when the transmittance of light of 380 to 480 nm of the front glass substrate is low. As a result, the color display balance becomes poor. In particular, since the blue phosphor of the PDP device has lower luminous efficiency than other phosphors, a front glass substrate that transmits the blue light emission wavelength as much as possible is desirable.

[0010] Further, in order to prevent halation, NiO or CoO as described in JP-A-11-1342 When these components are contained, these components reduce the transmittance almost uniformly over the entire visible wavelength region. Therefore, it is preferable that the luminance of the image is reduced by absorbing light emitted by red, green, and blue phosphors. There is a risk of consequences.

 [0011] Nd O is a very expensive raw material having a good transmittance in the visible wavelength region.

 twenty three

 For this reason, when it is added in a large amount, it becomes expensive.

[0012] Sarakuko, the PDP substrate needs to be a high strain point glass because it includes a heating step during panel fabrication. If the strain point is low, problems such as warpage occur during the process.

[0013] Further, the thermal expansion coefficient needs to be consistent with other members.

 [0014] As described above, the properties required for the PDP substrate have various powers, and a glass composition that satisfies all of them has not yet been obtained.

 The object of the present invention is to solve the above problems, suppress halation, have near-infrared absorption ability, and have excellent light transmission performance in the visible wavelength region of 380 to 770 nm, particularly 380 to 480 nm. It is another object of the present invention to provide a plasma display front glass substrate having a heat resistance and a thermal expansion coefficient suitable as a display substrate, and a plasma display device using the same.

 [0016] According to the present invention, in terms of weight%, the SiO force is 0 to 70, AlO is 0.5 to 5, N

 2 2 3

 a O 2-6, K O 8-16, Na O + K O 10-20, MgO 8-15, CaO 0-6

2 2 2 2

 , SrO force ~ 5, BaO 0 ~ 5, MgO + CaO + SrO + BaO 10 ~ 20, ZrO 0.5

 2

When the weight of the basic glass composition is 100% by weight as a coloring component and the basic glass composition is only ˜5, iron oxide is contained in an amount of 0.25 to 0.80% by weight. For plasma displays, the weight ratio of divalent iron oxide to total iron oxide (weight of divalent iron oxide Z weight of total iron oxide) in pig iron is 0.25 to 0.55 A front glass substrate is provided.

 Furthermore, according to this invention, the plasma display apparatus provided with said front glass substrate for plasma displays as a front glass substrate is provided.

 Brief Description of Drawings

 FIG. 1 is a transmittance curve (plate thickness: 2.8 mm) between the glass of Example 1 and the glass of Comparative Example 1.

Detailed description [0018] According to the present invention, halation is suppressed, near-infrared absorbing ability is provided, and light transmission performance in the visible wavelength region of 380 to 770 nm, particularly 380 to 480 nm is excellent. A front glass substrate for plasma display having a suitable heat resistance and thermal expansion coefficient as a substrate and a plasma display device using the same can be provided.

 [0019] SiO is a main component of glass, and if it is less than 60% by weight,

 2

 Deteriorates chemical durability. On the other hand, if it exceeds 70%, the high-temperature viscosity of the glass melt increases, making glass molding difficult. Moreover, the linear expansion coefficient of glass becomes too small. Therefore, the range is 60 to 70%, preferably 62 to 68%.

[0020] Al 2 O is a component that increases the strain point, and if the weight percent is less than 0.5, the effect is obtained.

 twenty three

 I can't. On the other hand, if it exceeds 5%, the high-temperature viscosity of the glass melt increases and the tendency to devitrification increases. Therefore, the range of 0.5-5%, preferably 0.5-4, more preferably 0.5-3% is preferred.

 [0021] Na 2 O is an essential component that acts as a flux when melting glass together with K 2 O. Less than 2%

 twenty two

 If it is, their action is insufficient, and if it exceeds 6%, the strain point decreases too much. Therefore, the range is 2 to 6%, preferably 2 to 5%.

[0022] K 2 O exhibits the same effect as Na 2 O and has a mixed alkali effect with Na 2 O.

 2 2 2

 It is an essential component that suppresses the migration of Lucari ion and increases the volume resistivity of the glass. If it is less than 8%, their action is insufficient, and if it exceeds 16%, the linear expansion coefficient becomes excessive and the strain point is too low, so that it is 8 to 16%, preferably 9 to 15%. The range is preferably 10-14.

 [0023] Regarding the amount of the alkali component R 0 (Na 0, K Ο), the total amount is made 10 to 20%.

 2 2 2

 Thus, the strain point, linear thermal expansion coefficient, high temperature viscosity and devitrification temperature can be maintained in appropriate ranges. If the total amount of alkali components is less than 10%, the coefficient of linear thermal expansion is too low.

The Young's modulus increases and the desired Young's modulus cannot be maintained. In addition, the devitrification tendency of glass increases. If it exceeds 20%, the strain point is lowered too much and the volume resistivity is lowered. Therefore, it is in the range of 10 to 20%, preferably 12 to 20%, more preferably 12 to 19%.

[0024] MgO has the effect of lowering the viscosity of the molten glass when the glass is melted and also has an increased strain point. Has the effect of raising. If it is less than 8%, their action is insufficient, and if it exceeds 15%, the tendency of devitrification of the glass increases and it becomes difficult to form molten glass. Accordingly, the range is 8 to 15%, preferably 8 to 14%, more preferably 8 to 13%.

 [0025] CaO has the effect of lowering the viscosity of the molten glass at the time of melting the glass and the effect of increasing the strain point of the glass. However, when it exceeds 6%, the tendency to devitrification increases. Therefore, the range is 0 to 6%, preferably 0.5 to 5%, and more preferably 1 to 4%.

 [0026] SrO is not an essential component, but has the action of reducing the high-temperature viscosity of the glass melt and suppressing the occurrence of devitrification in the presence of CaO. If it exceeds 5%, the density becomes too high, so a range of 5% or less, preferably 3% or less is desirable.

 [0027] Although BaO is not an essential component, it has the effect of suppressing the devitrification tendency of the glass melt and has the effect of lowering the Young's modulus. The range of 3% or less is desirable.

 [0028] Furthermore, within the above composition range, the total amount of divalent metal oxides RO (R is Mg, Ca, Sr, Ba) is in the range of 10 to 20%, so that the meltability of the glass is improved. While maintaining a good range, it is possible to obtain a glass having an appropriate range of thermal expansion coefficient by making the viscosity-temperature gradient moderate and improving the moldability of the glass, excellent in heat resistance, chemical durability, etc. . If the total RO is less than 10%, the high-temperature viscosity increases, making it difficult to melt and mold the glass. In addition, the strain point is lowered too much and the thermal expansion coefficient is lowered. On the other hand, if it exceeds 20%, the density increases, the tendency to devitrification increases, and the chemical durability decreases. Therefore, it is 10 to 20%, preferably 11 to 19, and more preferably 12 to 18%.

 [0029] In order for the glass to have both near infrared absorption performance and visible light transmission performance sufficiently, the ratio of R OZ (R O + R0) is preferably 0.40 or more. 0. If less than 4, trivalent iron oxide

twenty two

 The effect of suppressing light absorption in the visible wavelength region becomes insufficient, so that the transmittance of visible light, particularly light of 380 to 480 nm is too low. Therefore, the ratio of R 0 / (R O + R0) is 0.40 or more,

 twenty two

 Preferably it is 0.45 or more, more preferably 0.50 or more.

[0030] Further, in order to have both near-infrared absorption performance and visible light transmission performance and increase the strain point of glass, the ratio of MgOZRO (R is Mg, Ca, Sr, Ba) is 0.5. The above is desirable. If it is less than 0.5, the effect of suppressing light absorption in the visible wavelength region by trivalent iron oxide iron is ineffective. In addition to this, a desired strain point cannot be obtained. Therefore, the ratio of MgOZRO is 0.5 or more, preferably 0.60 or more.

[0031] ZrO has the effect of increasing the strain point of glass and improving the chemical durability of glass.

 2

 Have. When the content is less than 5%, their action is insufficient, and when the content exceeds 5%, the density increases, and any desired values cannot be maintained. Therefore, the range is 0.5 to 5%, preferably 1 to 3.5%.

 [0032] Acid ferrous iron (iron oxide (II) and iron oxide (III)) is essential for imparting near-infrared absorption performance to glass, and is preferably 0.25 to 0.80%. If it is less than 0.25, sufficient near-infrared absorptivity cannot be imparted. On the other hand, if it exceeds 0.80, the visible light transmittance is remarkably lowered! In addition, the weight ratio of the divalent iron oxide (iron oxide (II)) to the total amount of iron oxide (iron oxide (Π) and iron oxide (ΠΙ)) Iron weight Z total iron oxide weight) is an important value that determines the balance between near infrared absorption performance and visible light transmission performance.If this value is less than 0.25, sufficient near infrared absorption performance cannot be obtained. However, the visible light transmittance is too low. On the other hand, if it exceeds 0.55, the near-infrared absorption performance is sufficient, but the absorption of near-infrared rays also affects visible light transmission, which is not preferable.

 [0033] Further, in order to impart near-infrared absorption performance or suppress halation, CoO may be contained up to a range of 25 ppm or less as another coloring component, but if CoO exceeds 25 ppm, visible light may be contained. CoO content is 25ppm or less, preferably 20ppm or less, more preferably lOppm or less because the permeation performance deteriorates too much. In addition, in order to adjust the color tone of the glass to the desired color tone, NiO is 80 ppm or less and MnO is 150 pp as other coloring components.

 2 m or less, and Se may be contained up to the range of lOppm or less. However, if NiO exceeds 80 ppm, the absorption wavelength of the blue phosphor becomes remarkably absorbed.

 If it exceeds 2 ppm, the visible light transmission performance deteriorates too much, and if Se exceeds 10 ppm, the visible light transmission performance deteriorates too much, and its toxic viewpoint power is preferable.

[0034] The glass of a preferred embodiment of the present invention has substantially the above component strength, but may contain other components in a total amount of up to 3% within a range not impairing the object of the present invention. For example, SO, Cl, F, As O, etc. may be added up to 1% in total to improve glass melting, fining and moldability.

 3 2 3

. Also, TiO and CeO are used to prevent electron beam browning in PDPs. It may be contained up to 1% or up to 1% in total.

[0035] By using such a basic glass composition and coloring component, the glass substrate of the present invention has a transmittance T force of 850 nm or less when the thickness is 2.8 mm.

 850

 It has infrared absorption performance and has a transmittance of light with a wavelength of 550 nm.

 550

 The transmittance (T — T) of light with a long wavelength of 850 nm is 25% or more.

 850 550 850

 Excess ratio T Power difference of 75% or more and transmittance of light with a wavelength of 850 nm T (T — T) is 25

480 850 480 850

% Transmittance of light with a wavelength of 430 nm T Power Transmittance of light with a wavelength of 850 nm or more with T power of> 75%

 430

 When the difference from the transmittance T (T — T) is 25% or more, the light transmittance T at a wavelength of 380 nm, T force is 0% or more

850 430 850 380 and wavelength 850nm light transmittance T difference (T — T) can be 15% or more

 850 380 850

 It is. As described above, since visible light has a high transmittance power S of 380 to 480 nm, it can have both near infrared absorption performance and high visible light transmission performance. Note that the transmittance T of light having a wavelength of 850 nm is preferably 50% or less, more preferably 45% or less.

 850

[0036] The glass substrate of the present invention, it points forces consistency with other members in the plasma display panel during manufacture the thermal expansion coefficient is 70~90 X 10- ⁷ Z ° C, also the thermal deformation in the heat treatment Point force The strain point is preferably 570 ° C or higher.

 [0037] [Example 1 10 and Comparative Example 1 5]

 Hereinafter, the present invention will be described based on examples. However, the present invention is not limited to these examples.

 [0038] (Glass creation)

Silica sand, acid aluminum, sodium carbonate, sodium sulfate, potassium carbonate, magnesium oxide, calcium carbonate, strontium carbonate, barium carbonate, zirconium silicate and ferric oxide (iron oxide (ΠΙ)), In order to adjust the weight ratio of iron oxide (that is, ferrous oxide or iron oxide (Π)) and the total iron oxide, a blended raw material consisting of cellulose powder as a reducing agent and cobalt oxide as another coloring component is used. Filled in a platinum crucible and melted by heating at 1400-1600 ° C for about 6 hours in an electric furnace. That is, the total amount of iron oxide was added in the form of iron (III) oxide. In order to reduce a part of this acid iron (III) to acid iron (III), the reducing agent was added. During the heating and melting, the glass melt was stirred with a platinum rod to homogenize the glass. [0039] Next, the molten glass was poured into a vertical mold to form a glass block, which was transferred to an electric furnace maintained at 450 to 650 ° C and gradually cooled in the furnace. The obtained glass was homogeneous without bubbles or striae. A sample was prepared by cutting this glass and polishing it to a thickness of 2.8 mm.

 [0040] With respect to the glass sample thus prepared, the transmittance was measured in the visible light region and the near infrared region, and the weight ratio of the divalent iron oxide to the total iron oxide (the divalent acid concentration). Iron weight Z (weight of total iron oxide), strain point and coefficient of thermal expansion were measured. The results are shown in Table 1 and Table 2.

 [0041] The weight ratio of divalent iron oxide to total iron oxide (weight of divalent iron oxide Z weight of total iron oxide) was measured by chemical analysis. The strain point was measured by a beam bending method based on JIS R3103-2. The expansion coefficient was determined by measuring the average linear expansion coefficient at 30 to 300 ° C. using a thermomechanical analyzer TMA8310 (manufactured by Rigaku Corporation).

[table 1]

ガラス組成 Si0₂ 65.5 66.3 66.8 67 )4, 61.4 66.0 66

Glass composition Si0 ₂ 65.5 66.3 66.8 67) 4, 61.4 66.0 66

Al ₂ 0 ₃ 1.2 I .3 1.7 I .2 1.11 • 8 2.8 1.7 0.9 Na ₂ 0 3.0 4.0 3.5 3.6 1 2.1 4.3 3.6 K ₂ 0 12.4 14.3 12.7 II .2 I.9 • 6 11.9 8.0 10.7

R ₂ 0 (= Na _z O + K ₂ 0) 15.4 18.3 16.2 14.8, 0 14.0 12.3 14.3

MgO 10.9 I I .1 10.2 10.2 8.6 10.2 13.5 CaO 2.8 0.1 1.8 2.1 8 3.6 2.7 0.5 SrO 1.7 0.4 1.3 2 4.8 1.7 0.2 BaO 1 2.5 3.1

RO (Bi MgO + GaO + SrO + BaO 15.4 11.6 13.3 14.0 ί.7 2.6 17.0 17.1 17.3 rO 2.5 2.5 2.0 2.5 4 t.6 3.4 4.8 3.0 0.9

R ₂ 0 / (R ₂ 0 + RO) 0.50 0.61 0.55 0.51 L47 0.53 0.55 0.45 0.42 0.45 Fe ₂ 0 ₃ (wt%) 0.63 0.29 0.62 0. 0.78 0.63 0.63 0.63 Fe0 / (Fe0 + Fe ₂ O ₃ ) 0.39 0.38 0.36 0. 0.39 0.40 0.42 0.41 CoO (ppm) 19 19 NiO (ppm) 63 MnO _s (ppm) 123

Comparative Example 1 2 3 4 5

Glass composition Si0 ₂ 54.0 57.5 54.7 54.0 65.5

(wt%) Al ₂ 0 ₃ 9.0 6.5 6.8 8.5 1.2

Na ₂ 0 4.2 4.5 5.0 2.0 3.0

 12.4

Coloring ingredients

Transmittance (%)

- 4 歪点 °c 590 575 584 623 586

-4 strain point ° c 590 575 584 623 586

Expansion coefficient Χ 10 ^_7 Ζ 85 81 83 81 79

[0042] Examples 1 to 10 in Table 1 are glasses of the present invention, and Comparative Example 15 in Table 2 is a conventional high strain point glass. As is apparent from Table 1, all the glass substrates of the present invention have high visible light, particularly high transmittance of 380 to 480 nm, and excellent near infrared absorption performance. Furthermore, the strain point and the thermal expansion coefficient are values suitable for the front glass substrate for plasma display.

 [0043] On the other hand, the glasses of Comparative Examples 1 to 4 have near-infrared absorption performance, but are inferior in transmission performance of visible light, particularly 380 to 480 nm. The glass of Comparative Example 5 has a high visible light transmittance! /, But the near-infrared absorption performance is remarkably inferior.

 FIG. 1 shows transmittance curves of the glass of Example 1 and the glass of Comparative Example 1. It can be seen from FIG. 1 that the glass of this example has the same amount of iron oxide as the glass of comparative example 1 and the same ratio of divalent iron oxide Z total iron oxide as the glass of comparative example 1. It is clear that it has the same near-infrared absorption performance and excellent light transmission performance of visible light, especially 380-480nm.

Claims

The scope of the claims  [1] Substantially expressed in weight%, SiO force 0 to 70, Al O 0.5 to 5, Na O 2 to 6, K 2 O  2 2 3 2 2 force ^ 8 ~ 16, Na O + K O force 10 ~ 20, MgO force 8 ~ 15, CaO force 0 ~ 6, SrO force 0 ~ 5, Ba  twenty two  A group consisting of 0 to 5 O, MgO + CaO + SrO + BaO 10 to 20 and ZrO 0.5 to 5 only  2  When the weight of the basic glass composition and the basic glass composition is 100% by weight as a coloring component, the iron oxide is contained in an amount of 0.25 to 0.80% by weight. Plasma display, characterized in that the weight ratio of pig iron to total acid iron iron (divalent acid iron iron weight Z total acid iron iron weight) is 0.25-0.55 Front glass substrate. [2] Light transmittance at a wavelength of 850 nm when the thickness of the glass substrate is 2.8 mm T force ½0  850 % And below, transmittance of light with a wavelength of 550 nm T power of 75% and above and transmission of light with a wavelength of 850 nm  550  Difference from rate T (T — T) ¾5% or more, transmittance of light with wavelength 480nm T force 75% or more 850 550 850 480 and 850 nm wavelength light transmittance T difference (T — T) more than 25%, wavelength 430 nm  850 480 850  Light transmittance T of light with a power of 75% or more and a wavelength of 850 nm  430 850 430 ) Is 25% or more, light transmittance at a wavelength of 380 nm, T force ¾0% or more and light at a wavelength of 850 nm 850 380  2. The difference (T — T) with the transmittance T of the liquid crystal is 15% or more.  850 380 850  Front glass substrate for plasma display. [3] The front glass substrate for a plasma display according to claim 1 or 2, wherein CoO is contained as a coloring component in an amount of 0 to 25 ppm. [4] The front glass substrate for plasma display according to any one of claims 1 to 3, wherein the strain point is 570 ° C or higher. [5] a front glass substrate for plasma display according to claim 1 to 4 thermal expansion coefficient characterized in that it is a ^{70 X 10- 7 / ° C~90 X} 10- 7 / ° C. [6] The front glass substrate for plasma display according to any one of claims 1 to 5 as the front glass substrate;