JP2006188422A - Method of clouding glass especially borosilicate glass, and glass tube and plate glass produced from glass for light emitting means having turbidity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of and a glass for preventing light passage in an undesired portion, particularly glass for a light emitting means by eliminating defects in the conventional techniques. <P>SOLUTION: The glass is obtained by melting and performing a thermal after-treatment so as to separate the glass into at least two phases and to have turbidity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for turbidity of glass, in particular borosilicate glass, a light emitting means having turbidity, a glass tube made of glass and a flat glass made of glass. In particular, the glass is intended to be a fluorescent lamp glass. Glass with turbidity has scattering ability.

  Glasses for the manufacture of gas discharge tubes such as fluorescent lamps are known. These glasses should have high stability against solarization in addition to strong ultraviolet absorption properties, and must be resistant to the harsh conditions prevailing in such gas discharge tubes.

  Fluorescent luminaires, especially miniaturized fluorescent lamps, are particularly useful in the production of TFT liquid crystal displays (LCDs) and in the case of displays illuminated on the back (non-emitter displays, so-called backlight units). Used as a light source. For this application, such fluorescent luminaires have very small dimensions, and therefore the lamp glass has only a very thin thickness.

  Glass for such use has a transmission of visible light in particular up to the wavelength region below 400 nm, in particular below 380 nm. The transmittance is relatively constant and decreases rapidly. In other words, gas discharge tubes, particularly fluorescent lamps, emit large components in the ultraviolet range upon insufficient absorption of glass in the ultraviolet wavelength region. Such components have deleterious effects on surrounding structural members such as polymers and other plastics. Therefore, these structural members become brittle over time. This can make all products unusable. Such a particularly harmful emission line is the emission line of mercury at 313 nm. Glass for use in fluorescent lamps should absorb this emission line as completely as possible. Furthermore, the highest possible absorption of the emission line at 364 nm is desirable.

  A fluorescent lamp glass for said use which absorbs ultraviolet rays within a desired range is known from US Pat. However, it has been found that such glasses show strong discoloration and in some cases solarization in the visible light wavelength region. Already during the sealing of raw materials, a yellowish brown discoloration often occurs.

From Patent Document 2, a zirconium oxide-containing and lithium oxide-containing borosilicate glass having a high stability is known. This borosilicate glass is particularly suitable for use as a molten glass with an iron-cobalt-nickel alloy. Such glasses can also contain colored components such as Fe ₂ O ₃ , Cr ₂ O ₃ , CoO and TiO ₂ .

Patent Document 3 describes a glass for ophthalmic use. This glass has a special refractive index and Abbe index and a density suitable for it. Such glass exhibits UV blocking between 310 nm and 335 nm and contains TiO ₂ as an UV absorber. It is specified that for the production of this glass, clarification with As ₂ O ₃ and Sb ₂ O ₃ is not sufficient, so in many cases clarification with chlorine is necessary. Finally, here too, despite the fact that such glass is very thin, the combination of Fe ₂ O ₃ and TiO ₂ results in the coloration of the glass, and thus only quartz raw materials with an iron content of less than 100 ppm Is intended to be used.

Borosilicate glasses with a slight content of B ₂ O ₃ are also known. Such borosilicate glasses containing zirconium oxide and containing lithium oxide are described, for example, in US Pat. This glass has high acid stability and alkali stability, as well as stability in hydrolysis, and is particularly suitable for melting with iron cobalt nickel alloy. Such glasses can contain colored components such as Fe ₂ O ₃ , Ca ₂ O ₃ , CoO and TiO ₂ . However, it is also known that the boron component in such glasses provides low chemical stability. For this reason, heretofore glasses with a high boron content, ie greater than 25% by weight, have not been considered as glasses for use in gas discharge tubes. This is because these glasses have very poor chemical stability. Therefore, it has been assumed until now that the fluorescent layer contained in such a lamp reacts with the substrate glass (Substratglas) under the severe conditions which prevail there.
U.S. Pat.No. 5,747,399 German Patent No. A-198 42 942 U.S. Pat.No. 4,565,791 German Patent A-19842942

  The disadvantages of the fluorescent lamp glass based on the prior art are that the fluorescent lamp glass is transparent, for example, in the use of fluorescent lamp glass in the area of bushings, even in places where the following is not desirable: In order to prevent leakage of scattered light, it had to be made opaque, for example by the deposition of a lacquer layer, in particular a black lacquer. This is troublesome especially in the production method.

  The object of the present invention is therefore to eliminate the disadvantages of the prior art and to provide a method and in particular a glass, in particular a glass for a light-emitting means, which prevents the passage of light in undesirable places.

According to the invention, the problem is that the glass, in particular, has the following components:
SiO ₂ 55~85 weight%
B ₂ O ₃ > 0 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
TiO ₂ > 1.0 to 10% by weight
Since the glass for light emitting means, having a glass composition containing, by weight, is exposed to a predetermined cooling after melting or one or several subsequent thermal aftertreatments, the glass has a visible turbidity, Solved.

  Such turbidity can also be quantified by the scattering power σ of the glass body material.

  In general, there are two different ways in which such turbidity can be achieved. In the first method, the glass is heated to the melting temperature. Turbidity can be achieved in two different ways. In the first method, the glass is cooled very quickly and then maintained at a predetermined temperature, for example, 730 ° C. for 30 minutes, in order to separate the glass.

  Instead, the glass can be cooled to room temperature in a limited temperature range or over the entire temperature range, i.e., for example, at a cooling rate of 20 K / h or even less. The purpose is to achieve glass separation and thus also turbidity.

  As an alternative to the above method, the glass may first be rapidly cooled to room temperature. The glass is held at a holding temperature in the range between room temperature and 600-900 ° C, preferably 650-800 ° C for 1-120 minutes, preferably 2-60 minutes, quite preferably 5-30 minutes, for example 730 ° C. It can be heated and maintained there for 30 minutes. Instead of maintaining at 730 ° C. for 30 minutes, the glass is also heated to this temperature, from which, to a limited extent, 1 to 200 K / h, preferably 2 to 100 K / h, quite particularly preferably 5 to 50 K / h. For example, it can be cooled at a cooling rate of 20 K / h or even less. The purpose is to achieve glass separation and thus also turbidity.

  The Tyndall effect or Tyndall scattering (according to J. Tyndall 1868) is a collective concept of phenomena caused by light scattering in colloidal solutions or colloids in matter. When converging light passes through such colloidal material, a light cone (Tyndall cone) is visible from the side due to scattered light and appears as turbidity.

  The Tyndall effect can be explained by the theory of light scattering. Smaller particles with additional conditions | m | × particle size << λ / 2π (m = ratio of the refractive index of the particle to the matrix) relative to the light wavelength λ scatter light based on Rayleigh theory To do. In the case of small particles, the scattered light or Tyndall effect is therefore blue and the passing light is reddish. Rayleigh-Gans theory is used for particle size << λ | m |, and Mie theory is used for particle >> λ / 2π.

The glass according to the invention is a glass that has been separated into two or more amorphous phases after heat treatment. Glass ceramics can also be produced appropriately. At least one phase is an amorphous glassy phase and at least one other phase is a crystalline phase. It is preferred that this crystalline phase is a TiO ₂ precipitate, in particular rutile. For example, other phases such as anatase are possible depending on the operating conditions and the composition of the glass. It is preferred that a glass-ceramic is obtained when the thermal aftertreatment is carried out for a long time, preferably> 30 minutes, very preferably> 60 minutes. In a particularly preferred embodiment, the thermal aftertreatment is> 120 minutes.

  According to Gottfried Schroeder, “Industrial Optics”, Vogel Publishers 1990, the scattering power σ can be defined by the following equation.

σ = (L _{20 °} + L _{10 °} ) / (2 · L _{5 °} )
The disclosure of this document is fully incorporated herein.

In this case, a parallel bundle of light radiation is inserted perpendicular to the plane (hence ε = O °). That is, L _{5 °,} L _{20 °, and} L _{70 °} are light densities measured during reflection or transmission at corresponding angles to the normal to the surface. When the maximum light density occurs at an angle of ε = 0 °, and this density drops to the half maximum value at the angle ε = γ (L _γ = L _0/2 ), this angle is called the half-value angle γ. According to the classification shown in DIN (German Industrial Standard) 5036, page 4, weak scattering when σ ≦ 0.4 and γ ≦ 27 °, and strong scattering when σ> 0.4 and γ ≦ 27 °. is there. Scattering power σ = 1, L _{5 °} = L _{20 °} = When L _{70 °} holds, the half-value angle γ is not defined in this case.

  The various scattering powers of, for example, diffusing glass are recognized by the fact that the diffusing glass is more or less transparent for weak scattering and only translucent for strong scattering. For example, if you bring a type swatch behind the frosted glass and expand the distance between the frosted glass and the type swatch to a legible limit, the large limit distance is weak scattering, i.e., the light that passes through without scattering. Means a high percentage.

  If the fluorescent glass described in the present application is cooled rapidly, for example after melting, for example at a cooling rate of 200 K / h, the glass does not show any appreciable separation and is surprisingly particularly high in the visible region The transmittance is shown.

  In the present invention, the transparency of the described glass can be adjusted by an appropriate heat treatment.

  In the present invention, when the glass is cooled and / or reheated too slowly in the temperature range important for separation, a particularly high titanium content, preferably> 1.0%, particularly preferably> 2%, no Particularly preferably at 3%, an even glass matrix is separated into two or more phases. This results in separation (Tyndall effect), which scatters the passing light. That is, this glass has the above scattering ability.

  The degree of separation is a function of time and temperature. That is, as the temperature increases, a slight holding time is required for proper turbidity. Another possibility of the modified embodiment is to select and adjust the content of titanium dioxide.

  In the case of a gas discharge tube having an external electrode, the glass produced according to the invention is preferably used in the region of the electrode. The purpose is therefore to prevent unwanted light leakage.

  The glasses described in this application are surprisingly suitable as support glass (Substratglas) in gas discharge tubes. This is because the expected reaction between the glass and the fluorescent layer does not occur, at least under the dominant conditions during use, and the glass is sufficiently corrosive stable during its use.

It is particularly preferred that the fluorescent lamp glass is borosilicate glass. The borosilicate glass contains SiO ₂ as a first component and an alkali or alkaline earth metal oxide such as Na ₂ O or K ₂ O as well as boron oxide B ₂ O ₃ as the other components.

Borosilicate glasses with a content of B ₂ O ₃ between 5 and 15% by weight show a high chemical stability. Furthermore, such borosilicate glasses can be adapted to metals, such as tungsten or alloys, such as Kovar, in terms of coefficient of thermal expansion (CTE), depending on the choice of composition range. This prevents stress in the bushing area.

Borosilicate glasses with a content of B ₂ O ₃ between 15 and 25% by weight have good workability and a similarly good compatibility with the thermal expansion coefficient (so-called CTE) to tungsten metal or Kovar alloy Indicates.

Borosilicate glasses with a B ₂ O ₃ content between 25 and 35% by weight show a slight dielectric loss factor tan δ when used as fluorescent lamp glasses. This is particularly advantageous when using fluorescent lamps without electrodes (so-called EEFL, which is a lamp with external electrodes).

In general, the glasses described in this application comprise a TiO ₂ content of more than 1% by weight, particularly preferably more than 2% by weight and very particularly preferably more than 3% by weight.

In the case of the glass shown here, the total of TiO ₂ + B ₂ O ₃ is particularly preferably in the range of 5 to 35% by weight, particularly in the range of 10 to 25% by weight.

When the sum of TiO ₂ + B ₂ O ₃ is in the above range, it is quite preferable that separation occurs. In this case, TiO ₂ supports the separation in the boron-containing glass composition.

In a first embodiment of the invention, the base glass usually contains at least 60% by weight of SiO ₂ , with at least 61% by weight, preferably at least 63% by weight being suitable. A very particularly preferred minimum amount of SiO ₂ is 65% by weight. The maximum amount of SiO ₂ is 75% by weight, in particular 73% by weight, with 72% by weight and especially up to 70% by weight of SiO ₂ being quite particularly suitable. B ₂ O ₃ is included in the present invention in an amount of more than 5% by weight, preferably more than 8% by weight, preferably more than 10% by weight and in particular at least 15% by weight, with at least 16% by weight Particularly preferred. The maximum amount of B ₂ O ₃ is a maximum of 35% by weight, but preferably a maximum of 32% by weight, with a maximum of 30% and 25% by weight being particularly suitable.

Al ₂ O ₃ is included in an amount of 0 to 10% by weight, with a minimum amount of 0.5% or 1% by weight and especially 2% by weight being preferred. The maximum amount of this substance is usually 5% by weight, preferably 3% by weight. The individual alkali metal oxides Li ₂ O ₃ , Na ₂ O and K ₂ O are each independently 0-20 or 0-10% by weight, 0.1% by weight or 0.2 and especially 0.5 A minimum amount of% by weight is preferred. The maximum amount of the individual alkali metal oxides is preferably up to 8% by weight, 0% to 2% by weight of Li ₂ O, 0% to 7% by weight for Na ₂ O, K ₂ For O, 0 to 8% by weight is preferred. In the basic glass according to the invention, the total alkali metal oxide is 0 to 25% by weight and in particular 0.5 to 5% by weight. Alkaline earth metal oxides such as magnesium, calcium and strontium are included in the present invention in amounts of 0 to 20% by weight and in particular in amounts of 0 to 8% or 0 to 5% by weight, respectively. In the present invention, the total of alkaline earth metal oxides is 0 to 20% by weight, preferably 0 to 10% by weight. In this case, the alkaline earth metal oxides, in particularly suitable embodiments, have a total of at least 0.5% by weight or> 1% by weight.

Furthermore, the base glass is preferably 0 to 3 wt% ZnO, 0 to 3 or 0 to 5 wt% ZrO ₂ , 0 to 1 or 0 to 0.5 wt% CeO in the first embodiment. _2, and containing _Fe 2 _{O 3} 0-1% or 0-0.5% by weight. Furthermore, WO ₃ , Bi ₂ 0 ₃ and MoO ₃ can be contained separately from each other in amounts of 0 to 5% by weight or 0 to 3% by weight, in particular 0.1 to 3% by weight.

Although the glass is very stable to solarization when exposed to ultraviolet radiation, the solarization stability is PdO, PtO ₃ , PtO ₂ , PtO, RhO ₂ , Rh ₂ O ₃ , IrO ₂ and / or Ir. It has been found that it can be further increased by a small content of ₂ O ₃ . The usual maximum content of these substances is a maximum of 0.1% by weight, preferably a maximum of 0.01% by weight, with a maximum of 0.001% by weight being particularly preferred. The minimum content is usually 0.01 ppm for this purpose, preferably at least 0.05 ppm and in particular at least 0.1 ppm.

The glass can contain minor amounts of CeO ₂ , PbO and Sb ₂ O ₃ for improved chemical stability, clarity and processability. However, it is preferred that these glasses do not contain such materials. As long as it contains iron, iron is changed to oxidation degree 3 ⁺ by use of during melting for example nitrate-containing raw material by oxidation conditions. This minimizes discoloration in the visible wavelength region.

Regarding glass, the following was found. That is, the disadvantages mentioned above, in particular the discoloration of the glass in the visible wavelength range, are due to the following: the glass melt is substantially free of chlorine, in particular chlorine and / or Sb ₂ O ₃ Therefore, it is at least partially prevented by not being added to the glass melt.

That is, in the present invention, it has been discovered that the blue discoloration of the glass, which occurs when chlorine is not used as a fining agent, particularly when TiO ₂ is used, is prevented. In the present invention, the maximum content of chlorine and fluorine is 2% by weight, particularly 1% by weight, and a maximum content of 0.1% by weight is preferred.

  Furthermore, it has been found that sulfates used as fining agents, for example, also cause glass discoloration in the visible wavelength region, similar to the materials described above. Therefore, it is also preferable not to use sulfate. In the present invention, the maximum content of sulfate is 2, particularly 1% by weight, and a maximum content of 0.1% by weight is preferred.

  Visible wavelength region means in this application the wavelength region between 380 nm and 800 nm.

Furthermore, for glass, it has been found that the above disadvantages can be further prevented when clarification is done with As ₂ O ₃ and under oxidizing conditions, and when TiO ₂ is added to control UV blocking. It was. That is, it is clear that the above disadvantages are prevented when at least 80%, usually at least 90%, preferably at least 95% and in particular 99% of the contained TiO ₂ is present as Ti ^4+. became. In many cases, 99.9 and 99.99% of titanium is present as Ti ⁴⁺ in the present invention. In some cases, a 99.999% Ti ⁴⁺ content was found to be appropriate. Therefore, the oxidation condition means a condition in which Ti ⁴⁺ is present in the aforementioned amount or is oxidized at this stage. These oxidation conditions are easily achieved in the melt, for example, by the addition of nitrates, in particular alkali metal nitrates and / or alkaline earth nitrates. Oxidizing melts can also be obtained by blowing oxygen and / or dry air. Furthermore, for example, when the raw material is melted, it is possible to generate an oxidative melt using a burner adjusting means for oxidizing.

Despite the addition of nitrate to the glass during melting, preferably in the form of alkali metal nitrate and / or alkaline earth metal nitrate, the concentration of NO ₃ in the in-process glass has a maximum of 0 after clarification. 0.01% by weight, often only at most 0.001% by weight.

  A preferred glass according to the present invention has the following composition, for example, in the first embodiment.

SiO ₂ 60- <79% by weight
B ₂ O ₃ 5 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20% by weight,
K ₂ O 0-20% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight,
ZnO 0-3 wt%,
ZrO ₂ 0-7% by weight,
TiO ₂ > 1.0-10 wt%,
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1% by weight,
Nd ₂ O ₃ 0 to 1% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ⁻ 0 to 2% by weight, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ > 1.0 to 10% by weight,
ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ is 0.00001 to 0.1% by weight.

In another preferred composition according to the first embodiment, 0.5 to 25% by weight of the alkali metal oxide ΣLi ₂ O + Na ₂ O + K ₂ O is preferred, and / or the total ΣMgO + CaO + SrO + BaO of the alkaline earth metal oxide is 0 to 20% by weight.

  Other preferred compositions include:

SiO ₂ 63~75 weight%
B ₂ O ₃ 10 to 22 wt%,
Al ₂ O ₃ 0 to 3% by weight,
Li ₂ O 0 to 5 wt%,
Na ₂ O 0 to 7 weight,
K ₂ O 0-7 wt%, provided
ΣLi ₂ O + Na ₂ O + K ₂ O 0.5-15% by weight,
MgO 0-3 wt%,
CaO 0-5% by weight,
SrO 0 to 3 wt%,
BaO 0 to 3 wt%, provided
ΣMgO + CaO + SrO + BaO 0-5 wt%,
ZnO 0-3 wt%,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0-10 wt%,
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1.0% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^(2-) 0-2% by weight,
Cl ^- 0 to 2 wt%,
F ⁻ 0 to 2% by weight, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ > 1.0 to 10% by weight.

All the glass compositions preferably contain the amount of Fe ₂ O ₃ described above, and very particularly preferably substantially free of FeO.

  In the second embodiment of the present invention, the following composition is used. This composition is particularly characterized by high chemical stability against acids, alkalis and water.

SiO ₂ 60~85 weight%
_{3 to} 10% by weight of B ₂ O ₃
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 5-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0.5 to 20% by weight,
ZnO 0-8% by weight,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0-10 wt%,
Fe ₂ O ₃ 0 to 5% by weight,
CeO ₂ 0-5% by weight,
MnO ₂ 0-5% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
0-5 wt% PbO,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃
Is at least> 1.0-10 wt%, wherein ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ is 0.1 wt%,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ⁻ 0 to 2% by weight.

A second embodiment of a glass suitable for the method has a minimum content of SiO ₂ of at least 60% by weight, preferably at least 62% by weight, with a minimum content of 64% by weight being particularly preferred. The maximum content of SiO _{2 in} the glass according to the invention is at most 85% by weight, in particular 79% by weight, preferably at most 75% by weight. A particularly preferred maximum content is 72% by weight. The very high SiO ₂ content is characterized by a small dielectric loss factor tan δ and is therefore particularly suitable for fluorescent lamps without electrodes.

The content of B ₂ O ₃ is at most 10% by weight, in particular at most 5% by weight, with a content of at most 4% by weight being preferred. A maximum content of at most 3% by weight of B ₂ O ₃ is particularly preferred. However, this material comprises in a preferred embodiment at least 0.1% by weight, with 0.5% by weight being preferred. A minimum content of 0.75% by weight is particularly preferred and 0.9% by weight is very particularly preferred.

The glass according to the second embodiment of the invention can in each case be free of Al ₂ O ₃ , but the glass usually contains Al ₂ O ₃ of 0.1, in particular 0.2% by weight. The minimum content of A minimum content of 0.3% by weight is preferred, a minimum content of 0.7% by weight, in particular at least 1.0% by weight, is particularly preferred. The maximum content of Al ₂ O ₃ is usually 10% by weight, preferably a maximum of 8% by weight. In many cases, a maximum content of 5% by weight, in particular 4% by weight, proved to be sufficient. Al ₂ O ₃ is particularly used for improving the crystallization stability of glass.

The glass based on the second embodiment contains an alkali metal oxide and an alkaline earth metal oxide. In so doing, the total content of alkali metal oxides is at least 0.5% by weight, in particular at least 2% by weight, but preferably at least 4% by weight, with a minimum total amount of alkali metal oxides of at least 5% by weight. Particularly preferred. The maximum content of all alkali metal oxides is at most 25% by weight, with a maximum content of 20% by weight and in particular 15% by weight being particularly preferred. In many cases, it has been found that a maximum content of 10% by weight is sufficient. Among them, the content of Li ₂ O is in the present invention from 0% by weight to at most 10% by weight, with a maximum content of at most 8% and in particular 6% by weight being preferred. K ₂ O is included in an amount of at least 0% by weight and at most 20% by weight, with a minimum content of 0.01% by weight, preferably 0.05% by weight being preferred. In individual cases, a minimum content of 1.0% by weight has proved suitable. The maximum content of K ₂ O is, in a preferred embodiment, a maximum of 18% by weight, with a maximum of 15 and especially a maximum of 10% by weight being preferred. In many cases it has been found that a maximum content of 5% by weight is sufficient.

The single content of Na ₂ O is 0% by weight in each case and a maximum of 20% by weight. However, the content of Na ₂ O is at least 1% by weight, in particular at least 3% by weight, preferably at least 5% by weight, in particular at least 10% by weight. In a particularly preferred embodiment, sodium oxide is included according to the invention in an amount of at least 12% by weight. The preferred maximum amount of Na ₂ O is 18% or 16% by weight, with an upper limit of 15% being particularly preferred.

  The content of individual alkaline earth metal oxides is up to 20% by weight with respect to CaO, but in individual cases a maximum content of 18% by weight, in particular up to 15% by weight, is sufficient. Although the glass according to the present invention may not contain a calcium component, the glass according to the present invention usually contains at least 1% by weight of CaO and preferably has a content of at least 2% by weight, in particular at least 3% by weight. In practice, a minimum content of 4% by weight has proven appropriate. The lower limit for MgO is in each case 0% by weight, but is preferably at least 0.3% by weight and preferably at least 0.5% by weight. The maximum content of MgO in the glass according to the invention is 8% by weight, preferably 00 up to 7% by weight and in particular up to 6% by weight. SrO and / or BaO can be omitted completely in the glass according to the present invention. However, at least one or both of these substances are included in a content of 0.5% by weight, preferably at least 1% by weight. The total content of all alkaline earth metal oxides obtained in the glass is at least 0.5% by weight and at most 20% by weight, with a minimum content of 1% by weight, in particular 2% by weight being preferred. In many cases, a minimum content of 6 or 7% by weight has proven appropriate. A preferred maximum content of alkaline earth metal oxide is 18% by weight, with a maximum of 15% being preferred. In some cases, a maximum content of 12% by weight proved to be sufficient. The glass according to the present invention is preferably soda lime glass.

The glass according to the second embodiment may not contain ZrO, but preferably contains a minimum content of 0.1% by weight and a maximum content of at most 8% by weight, preferably at most 5% by weight. A maximum content of 3% or 2% by weight can be quite suitable. ZrO ₂ was included in an amount of 0-7% by weight, in particular 0-5% by weight, and it was found that a maximum content of 3% by weight is sufficient in many cases.

The glass according to the second embodiment, in a preferred embodiment, has a TiO ₂ , PbO, As ₂ O ₃ and / or Sb ₂ content of greater than 0.3% by weight and at most 10% by weight, in particular at most 7% by weight. It has a total content of O ₃ . In this case, the preferred minimum content of As ₂ O ₃ and / or Sb ₂ O ₃ is at least 0.01% by weight, preferably at least 0.05% by weight and in particular at least 0.1% by weight. In this case, the usual maximum content is at most 2% by weight, in particular at most 1.5% by weight, with a maximum of 1% by weight and in particular 0.8% by weight being particularly preferred. Of the above components, it is preferable that TiO ₂ is contained in the glass according to the present invention in a concentration of> 1.0% by weight. The maximum content of TiO ₂ is preferably 8% by weight, preferably at most 5% by weight. The preferred minimum content of TiO ₂ is 0.5% by weight and in particular 1% by weight. The glass contains 0 to 5% by weight of PbO, with a maximum content of 2% by weight, in particular a maximum of 1% by weight being suitable. It is preferred that the glass does not contain lead. The content of Fe ₂ O ₃ and / or CeO ₂ is 0 to 5% by weight, preferably 0 to 1 and especially 0 to 0.5% by weight. The content of MnO ₂ and / or Nd ₂ O ₃ is 0 to 5% by weight, preferably 0 to 2, particularly 0 to 1% by weight. The components Bi ₂ O ₃ and / or MoO ₃ are each included in an amount of 0 to 5% by weight, preferably 0 to 4% by weight. As ₂ O ₃ and / or Sb ₂ O ₃ are each contained in the glass according to the invention in an amount of 0 to 1% by weight, with a minimum content of preferably 0.01, in particular 0. 02% by weight. The glass according to the invention, in a preferred embodiment, optionally contains a small amount of 0 to 2% by weight of SO ₄ ²⁻ and Cl ⁻ and / or F ⁻ as well in amounts of 0 to 2% by weight, respectively. . In this case, the total amount of Fe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + As ₂ O ₃ + Sb ₂ O ₃ is 1.0 to 10% by weight, preferably 2% by weight or 3.0 to 8% by weight.

If the glass does not contain a multivalent fining agent such as As ₂ O ₃ and / or Sb ₂ O ₃ , a fining agent such as chlorine and / or sulfate may be added to the glass.

  The glasses according to the first and second embodiments are particularly suitable for producing flat glass, especially by the float process, and the production of tube glass is particularly preferred. This glass is suitable for the production of tubes having a diameter of at least 0.5 mm, in particular at least 1 mm, with an upper limit of at most 2 cm, in particular at most 1 cm. Particularly preferred diameters of the tube are between 2 mm and 5 mm, with upper limits of 8 mm and 5 mm being preferred. It has been found that such a tube has a wall thickness of at least 0.05 mm, in particular at least 0.1 mm, with at least 0.2 mm being particularly preferred. The maximum thickness is at most 1 mm, preferably at most <0.8 mm or <0.7 mm.

  The fluorescent lamp glasses described in this application are particularly suitable for use in gas discharge tubes and fluorescent lamps, in particular miniaturized fluorescent lamps, and quite particularly for illumination, such as electronic display devices such as displays and for example Suitable for LCD screens in the case of mobile phones and computer monitors, especially for backlighting. The preferred display as well as the screen is a so-called flat display, in particular a flat backlight device. For example, a light emitting means containing no halogen, such as a light emitting means based on discharge of xenon atoms (xenon lamp), is particularly preferable. It has been found that this embodiment is particularly environmentally friendly.

It is preferred that the glasses described herein have slight dielectric properties. In this case, the dielectric constant is a maximum of 12 at 1 MHz and 25 ° C., preferably below 10. Values below 7 and in particular below 5 are quite particularly preferred. The dielectric loss factor tan δ [10 ⁻⁴ ] is a maximum of 120, preferably less than 100. Loss rates below 80 are particularly preferred, values below 50 and below 30 are particularly preferred. Values below 15 are quite particularly preferred.

  The glass described in this application is particularly for use in fluorescent lamps (EEFL) with external electrodes, and the electrode or electrode bushings are melted with the lamp glass, eg made of Kovar alloy, molybdenum, tungsten, etc. It is also suitable for fluorescent lamps made through glass. In the case of external electrodes, these electrodes can be formed by, for example, a conductive paste. A typical light emitting device using the glass according to the present invention is shown in the drawings.

  In the present invention, in particular in the case of the above-mentioned glasses according to the first and second embodiments, a suitable operation, in particular annealing, turbidity (Truebungen), ie a specific scattering power σ can be adjusted. .

  In order to adjust the predetermined turbidity, the glass is subjected to an annealing process, ie a thermal post-treatment. For example, turbidity is already obtained when a glass having the following composition (% by weight on an oxide basis) is heated in a heat treatment at a temperature of> 680 ° C. for less than 1 minute.

SiO ₂ 64.284
B ₂ O ₃ 19.00,
Al ₂ O ₃ 2.65,
Li ₂ O 0.65,
Na ₂ O 0.75,
K ₂ O 7.45,
ZnO 0.6,
TiO ₂ 4.5,
Fe ₂ O ₃ 0.016,
As ₂ O ₃ 0.1
If the annealing time is extended to, for example, 5 minutes or 10 minutes, the glass is opaque to visible light. If it is desired to lower the temperature and achieve the same turbidity at low temperatures as in the case of thermal aftertreatment, the annealing time must be extended accordingly. In order to produce a visible turbidity that is already reached after a time of 1 min or less at a temperature> 680 ° C., for example, the same glass composition must be annealed at 620 ° C. for 30 min.

  When it is intended to precisely adjust the degree of turbidity, annealing at low temperatures is particularly preferred. This is because better process control is guaranteed by a longer time.

  Turbidity or the desired turbidity is achieved even in the multi-stage process that is usual for the manufacture of fluorescent lamps.

  In the manufacture of fluorescent lamps, the first step of heating the glass is preferably used, for example, to deposit the fluorescent layer necessary for the fluorescent lamp on the basic glass. Following the heating of the glass, the glass is cooled in the second step. The cooling of the glass from the heating temperature of the first step can be done, for example, at room temperature or at a specific holding temperature.

  As shown in FIG. 5, the linear dependence of turbidity with temperature and time is shown as a first order approximation. Visible turbidity no longer occurs below this curve set by temperature and time.

  It is preferable that the glass has a scattering power of σ> 0.1. The glass is so treated and appears milky to the viewer due to its high scattering power.

  Glass turbidity does not need to be done by a subsequent annealing step, but can be achieved immediately after melting of the glass as well, as shown in FIG. By keeping for a predetermined time above the indicated temperature limit.

  A combination of an annealing process immediately after melting in the hot forming process and a subsequent annealing process is also possible.

  When glass, particularly the glass according to the first and second embodiments of Table 1A, is used for a fluorescent lamp as described in the present invention, the glass is first heated as described above, followed by cooling. can do. As described in the introductory part of the specification, in performing the appropriate process, this results in the glass obtained being completely transparent as a fluorescent lamp glass, i.e. having a thickness d = in the visible wavelength region. At 0.2 mm, it will have> 90% transmission.

  In the case of lamps, in particular fluorescent lamps and so-called backlights (CCFL), at the sides of the lamp, especially when trying to prevent radiation leakage at the point of sealing with the electrode bushings, in these areas exactly Table 1A The electrodes according to the first and second embodiments A1 and A2 of the electrode are heated to a temperature during which the desired area is opaque to visible light for a predetermined time during electrode sealing. This turbidity can be maintained or achieved in a subsequent annealing step.

  By this heat treatment, the transparent glass first becomes turbid like milk in the heated area. That is, the glass has a scattering power σ> 0.1, preferably σ> 0.4, according to the present invention.

  The high scattering power makes fluorescent lamps with such fluorescent lamp glasses opaque to light, especially in the area of electrode bushings, thus preventing unwanted leakage of radiation at these points of the lamp. Bring things.

  This method can also be used in the case of gas discharge lamps without electrodes, so-called EEFL lamps. In the case of such a lamp, this method is used to give the side a high scattering power in order to prevent light leakage at the side.

  However, this method is not limited to the side of the lamp, but can also be used for light shielding in the light emitting area. It is also possible to apply moldings, insert patterns, and partially block the glass, especially the lamp body area. For example, when a fluorescent lamp glass molding is appropriately applied, it is possible to darken a dot-like pattern, an annular pattern, or the entire surface.

  An advantage of the glass according to the present invention is that, for example, in order to reduce light emission at an undesired place, an additional component such as a paint is not required unlike the prior art.

In the case of TiO ₂ -containing glasses according to the invention, the method according to the invention leads to the separation of the glass into phases for these glasses under the conditions described above. Depending on the process parameters, this separation can come out in various ways. As a result of this, various strong turbidities of the glass occur. Furthermore, the wavelength region can be adjusted by the size / amount of the separated phases. In this wavelength range, the glass must be opaque.

It can generally be said that the larger the separated phase in terms of expansion, the greater the wavelength at which scattering or absorption occurs. The various phases of the separated system are glassy and / or crystalline phases. These phases, in particular, glass is at least _B 2 _{O 3} of greater and at least _B 2 _{O 3} less or more at least of TiO ₂ and TiO ₂ less phases.

It is preferable that this B ₂ O ₃ -rich and B ₂ O ₃ -rich phase is particularly amorphous. Under special conditions (e.g. long retention times at high temperatures) a crystalline phase part is formed. In a glass containing a large content of TiO ₂ , for example, rutile is formed.

  What is decisive for good turbidity due to having σ> 0.1 is the large difference in refractive index between the individual phases.

  The structure of separation may be spinodal or binodal. A permeable structure or a liquid particle structure may occur.

  The separation or crystallization temperature is between 50 ° C. and 400 ° C. above the Tg, preferably 50 ° C. to 200 ° C. above the Tg.

  The size of the separated phase of the liquid particles is from 100 nm to 1000 μm, preferably from 500 to 100 μm, very particularly preferably from 1000 nm to 1 μm.

  Depending on the adjustment of the process parameters, rutile microcrystals can also be generated. These microcrystals can be achieved in sizes of 100 nm to 1000 nm, preferably 500-100 μm, very particularly preferably 1000 nm-1 μm.

  When the separated phase is in the wavelength region of light, a specific wavelength region can be absorbed. In this case, the size of the separated phase correlates with the wavelength at which absorption occurs up to that wavelength. The separation effect on the two glassy phases or the glassy and crystalline phases can be exploited to adjust the transmission, for example UV blocking.

  In particular, in the case of a fluorescent lamp, this method is suitable for shielding the region between the end of the fluorescent layer and the sealing of the electrode.

  In the case of a lighting body, the light that leaks to the side or in general undesired, for a certain use, for example, a molding process using a photoresist (Photostrukturierungsprozesse), or a certain contact with the light It may be advantageous when in contact with photosensitive materials, which are only desired.

  As indicated previously, the thermal aftertreatment according to the present invention can also be incorporated into the reworking of glass tubes. Such thermal post-treatment, for example in the production of miniaturized gas discharge lamps or fluorescent lamps, is a process step in which the glass is heated again or wholly or partially after manufacture, for example as a glass tube, for example Glass tube alignment or electrode sealing to compensate for undulations in the glass tube due to seizure of the phosphor layer, manufacturing, or to form the tube into a U-shape, corrugation, jagged, snail, or spiral shape is there.

  The above process steps can likewise be carried out with the glass according to the invention when the glass is in a flat shape. These flat glasses are preferably used in flat backlight systems (eg, the OSRAM Planon® type). Here, on the one hand, the cover plate can be produced from the glass according to the invention. Since the separate glass according to the present invention performs the light scattering function, it is advantageous, for example, that in other cases ordinary diffuser plates (usually made of polymer) may not be used. Furthermore, a plurality of regions can be appropriately turbid in the flat glass. Flat glass can be used as support glass with or without a molded product. Turbidity of the flat glass can also be performed in the molding process as well. Preferred shapes are corrugated and, for example, moldings formed by deep drawing, such as “valleys and peaks”, grooves, and laminates. The purpose is to save the so-called spacers (spacers between the support and the cover glass) that are otherwise necessary. Furthermore, this molded product can be used to increase luminous efficiency.

The heat treatment can be performed as a separate process at a predetermined temperature. At high temperatures, a short time is sufficient. 0
This annealing step can likewise be achieved by passing a predetermined temperature profile (Durchlaufen). Various heating rates and holding times at a given temperature are possible.

  Besides the glass turbidity method, in which the glass has a scattering power> 0.1 in particular, the invention makes use of the glass produced by this method and in particular the following fluorescent lamps. This fluorescent lamp has at least partly a region with turbidity, in particular a scattering power σ> 0.1. The purpose is to prevent light leaking in this area.

  In addition to use in the area of light emitting means, such glasses can also be used, for example, to produce barcodes on the basis of glass, to provide logos in the glass and to form the glass in three dimensions. Used. For this purpose, the glass can be heated locally with a laser. In general, as a method of forming a molding on glass, all methods capable of locally heating the glass, for example, femtosecond laser or infrared heating means for selectively heating the glass are possible. It is.

  Hereinafter, the present invention will be described in detail with reference to the drawings and embodiments. FIG. 1 shows the principle diagram of a low-pressure discharge lamp, in particular a fluorescent lamp, in particular a fluorescent lamp, which is very particularly preferably miniaturized.

  FIG. 1 shows a so-called backlight lamp manufactured from a drawn tube glass. The central part 10 with reference numeral 10 is quite transparent. The bushing metal wires 14.1, 14.2 are inserted only in the two open ends 12.1, 12.2. The bushing is melted with a transparent tube glass, for example, in the annealing stage. By annealing, the open ends 12.1, 12.2 are turbid in milk color, thus preventing the leakage of scattered radiation.

  It is preferred that the glass in the region of the bushing is selected so that the expansion coefficient of the glass is in great agreement with the expansion coefficient of the metal wires 14.1, 14.2.

  FIGS. 2 to 4 illustrate the use of a backlight lamp so manufactured according to the invention.

  FIG. 2 shows a special use for the following applications. That is, in such an application, a plurality of individual downsized fluorescent lamps 110 made of glass according to the present invention are used in parallel to each other and provided on a plate 130 having a plurality of depressions 150. , The emitted light is reflected on the display. A reflective layer 160 is attached above the reflective plate 130. This reflective layer evenly distributes the light emitted by the fluorescent lamp 110 in the direction of the plate 130 as a kind of reflector, thus causing an even illumination of the display. This device is preferably used for a larger display, for example a television device.

  In the embodiment of FIG. 3, the fluorescent lamp 210 can also be attached to the display 202 on the outside. In this case, the light is evenly distributed across the display by a light transmission plate 250 used as a light guide, so-called LGP (light guide plate). Such a light transmission type plate has, for example, a surface with a molded product for dispersion of light. By applying the molding, the light is scattered and dispersed from the light-guided or light-transmitting plate.

  The fluorescent lamps 110 and 210 used in the light emitting device shown in FIGS. 2 and 3 can have glass tubes. The fluorescent lamp can have an electrode in the glass tube and an external electrode.

FIG. 4 shows another embodiment of the present invention. In this embodiment, the light emitting unit 310 includes a disk 315 with a molded product, a support disk 317, and boundary walls 390.1 and 390.2. These walls have an enclosed space 392. This enclosed space is in this case divided into individual radiation spaces 360.1, 360.2, 360.3, 360.4, 360.5. This section is formed by a plurality of channels having a predetermined depth (d _channel ) and a predetermined width (W _channel ) by parallel partition walls, i.e. so-called barriers 380 having a predetermined width (W _rib ), These channels are made by providing a discharge fluorescent material 350 attached to a support disk 317 with a predetermined thickness. These channels, together with the disk having the phosphor layer 370, form a plurality of radiation spaces 392. The backlight device shown in FIG. 4 is a gas discharge lamp having no electrode. That is, there is no bushing and there are only external electrodes 330a and 330b. The cover disk 410 shown in FIG. 4 provided above the light emitting unit 310 may be an opaque diffuser disk or a transparent disk, depending on the structure of the system. The lamp device shown in FIG. 4 without electrodes is a so-called EEFL (External Electrode Fluorescent Lamp) device. However, in principle, inner bonding is also possible. That is, plasma can be ignited by the inner electrode. This type of ignition is another technique. Such a system is called a CCFL (Cold Cathode Fluorescent Lamp) system. The device forms a large, flat backlight and is therefore also called a flat backlight. In the method according to the invention, the flat-backed disc and / or the cover disc 410 can be made turbid by selective heating, for example. By local heating, for example with an infrared emitter or laser, the predetermined area 400 of the cover plate, for example, has a high scattering power and can thus be turbid.

  The present invention will be described in detail by the following embodiments.

  The glass according to the invention was produced in a known manner and compared with the glasses described as comparative examples. The comparative glass was not exposed to heat treatment. Since the comparative glass was not exposed to heat treatment, no separation of the glass into various phases was confirmed. Therefore, these glasses have no turbidity at all. In this case, the raw material was melted in a flint glass crucible at about 1300 ° C.

  Tables 1A to 10B below describe glass compositions that are suitable for use in light emitting devices, particularly so-called backlights, and that exhibit turbidity after heat treatment. Ingredients below the composition range of these glasses are included (in weight percent based on oxide).

SiO ₂ 55~79% by weight,
B ₂ O ₃ 12.5-25% by weight,
Al ₂ O ₃ 0.5 to 10% by weight,
ΣLi ₂ O + Na ₂ O + K ₂ O 1-16 wt%,
ZrO ₂ 0-5% by weight,
ΣTiO ₂ + PbO + Sb ₂ O ₃ 1.0 to 11% by weight, provided that TiO ₂ is always ≧ 1.0% by weight.

  The following special composition ranges are particularly preferred when melting with tungsten bushings.

SiO ₂ 73~79% by weight,
B ₂ O ₃ 12.5-25% by weight,
Al ₂ O ₃ 0.5 to 10% by weight,
ΣLi ₂ O + Na ₂ O + K ₂ O 1-11 wt%,
ZrO ₂ 0.01 to 5% by weight,
ΣTiO ₂ + PbO + Sb ₂ O ₃ 1 to 11% by weight, provided that TiO ₂ is always ≧ 1.0% by weight.

The coefficient of thermal expansion (CTE) for glass having such a composition range is 34-43 × 10 ⁻⁷ / ° C. between 30 ° C. and 380 ° C. Therefore, the coefficient of thermal expansion (CTE) of the glass is in the range of the thermal expansion of the tungsten wire and therefore no stress is actually generated in the bushing region.

  The following special composition ranges (% by weight on oxide basis) are preferred when melting with a Kovar® bushing.

SiO ₂ 55~73% by weight,
B ₂ O ₃ 15.5-25% by weight,
Al ₂ O ₃ 1~10 wt%,
ΣLi ₂ O + Na ₂ O + K ₂ O 4-16% by weight,
ZrO ₂ 0.01 to 5% by weight,
ΣTiO ₂ + PbO + Sb ₂ O ₃ 1 to 11% by weight, provided that TiO ₂ is always ≧ 1.0% by weight.

In this regard, the coefficient of thermal expansion CTE is between 43 and 55 × 10 ⁻⁷ / ° C. Accordingly, the coefficient of thermal expansion CTE of glass is within the range of the coefficient of thermal expansion of Kovar (registered trademark) wire. Therefore, no actual stress is produced in the area of the bushing. Table 1A, the 1B, 15 to 17% by weight of _B 2 _{O 3} content and> 1.5 wt.% Of glass having a content of TiO ₂ is shown. The glass is referred to as Embodiments 1 to 5 and exhibits turbidity during an appropriate heat treatment, particularly after annealing. Comparative Examples 1 to 4 have a TiO ₂ content of <1.5% by weight. In these comparative examples, turbidity could not be clarified despite the post-annealing treatment.

実施の形態６ないし１３は、＞１．５重量％のＴｉＯ２含有量を有する。適切な熱処理の際に、これらガラスは熱処理中に濁る。 The glass having a content of B ₂ O ₃ in the range of 15 to 25% by weight and shown in Tables 1A and 1B exhibits good workability, and as described above, in terms of the coefficient of thermal expansion, the bushing The material can be adapted to tungsten and kovar.

Embodiments 6 to 13 have a TiO2 content of> 1.5% by weight. During proper heat treatment, these glasses become turbid during heat treatment.

Comparative Examples 5 to 9 have a TiO ₂ content of <1.5% by weight. During proper heat treatment, these glasses did not become turbid during heat treatment.

The glass based on Comparative Example 5 was still transparent after the thermal aftertreatment, whereas the glass based on Embodiment 6 showed turbidity. The glass according to Embodiment 6 has a TiO ₂ content of> 1.5% by weight.

All the glasses shown in Table 3 based on the embodiment described in 7-9 show turbidity during a suitable heat aftertreatment at 730 ° C. for 30 minutes.

The glass based on Comparative Example 6 in Table 4 is still transparent after the annealing treatment, whereas the glass based on Embodiment 10 in Table 4 shows turbidity. The glass according to Embodiment 10 was exposed to a thermal aftertreatment at 730 ° C. for 30 minutes.

The glass based on Comparative Example 7 in Table 5 is still transparent after the annealing treatment, whereas the glass based on Embodiment 11 in Table 5 has turbidity. The thermal aftertreatment continued at 730 ° C. for 30 minutes as well.

  Comparative Examples 8 and 9 did not show turbidity after the heat aftertreatment and were transparent. In contrast, the glasses based on Embodiments 12 and 13 are characterized by visible turbidity and Tyndall effect. The thermal aftertreatment lasts 30 minutes at 730 ° C.

Tables 8 to 10 show glasses having a B ₂ O ₃ content between 9% and 20% by weight and a SiO ₂ content between 60% and 73% by weight. These glasses are particularly suitable for bushings made of Kovar alloy in terms of expansion.

表１Ａないし１０Ｂの実施の形態１ないし３０に基づくガラスが、ランプ構造の領域に用いられるとき、これらのガラスは、例えばガラス引張り成形（Glaszug）でまずは管に成形され、あるいは、引き上げ法、圧延法またはフロート法により平板ガラスとして成形される。 Embodiments 14 to 30 have glass turbidity during appropriate heat treatment. On the other hand, Comparative Examples 10 and 13 do not show turbidity. Again, a thermal post-treatment at 730 ° C. (furnace temperature) for 30 minutes was performed.

When glasses according to embodiments 1 to 30 of Tables 1A to 10B are used in the area of the lamp structure, these glasses are first formed into tubes, for example by glass tensioning (Glaszug), or by pulling, rolling It is formed as a flat glass by the method or the float method.

  The glass is heated for a period of 100-200 seconds at a furnace temperature of 700 to 750 ° C. resulting in a glass temperature of about 620 ° C., especially for baking of the phosphor layer, followed by cooling at a cooling rate of> 200 K / h. Is done. A sufficiently transparent glass with no apparent turbidity is then produced. The measured scattering power of the glass thus produced is σ <0.1.

  In another heating step, the cooled and sufficiently transparent glass is brought to a glass temperature of, for example, about 720 ° C., for example for 30 to 60 seconds, preferably 30 seconds to 30 seconds, for the formation of bushings for fluorescent lamps. It can be heated for 30 minutes, preferably 30 seconds to 15 minutes. This achieves turbidity as previously indicated with respect to the embodiment. In the present application, the glass temperature means a temperature generated in the glass itself. This temperature is measured, for example, with a pyrometer. Instead, the thermocouple can be attached directly to the glass. The opposite of the glass temperature is usually the temperature above the glass temperature.

This thermal post-treatment forms at least two phases. Glass is separated into at least _B 2 _{O 3} of greater and at least _B 2 _{O 3} less or more at least of TiO ₂ and TiO ₂ less phases.

  The phase separation temperature or crystallization temperature is between 50 ° C. and 400 ° C. above the Tg temperature, preferably between 50 ° C. and 200 ° C. above the Tg temperature.

  In response, the glass shows turbidity (diffuse daylight) that can be recognized by the eye. The scattering power in the annealed region is preferably σ> 0.1. Therefore, the bushing area appears milky.

  FIG. 5 shows the onset of turbidity for the thirteenth embodiment shown in Table 8 and the second embodiment shown in Table 1A.

  Regarding the onset of turbidity, the temperature and holding time shown in FIG. 5 during the annealing in the inclined furnace become clear. Curve 1000 represents the furnace temperature. The furnace temperature must be exceeded for the stated time of thermal aftertreatment. The purpose is that the turbidity starts in the case of the glass having the glass composition according to the second embodiment. Here, the turbidity that can be recognized by the eyes in diffuse daylight was used as a criterion for turbidity. It can clearly be seen that the temperature at the start of turbidity decreases as the time of the thermal aftertreatment increases.

  Curve 1002 represents the furnace temperature that must be exceeded at the stated time. Therefore, in the case of glass having a glass composition based on Embodiment 13, turbidity occurs, and turbidity occurs during the thermal post-treatment.

A decrease in the temperature limit line is also observed with increasing B ₂ O ₃ content. That is, the temperature limit line 1000 for a glass composition having a B ₂ O ₃ content of 19.0% by weight and a TiO ₂ content of 4.5% by weight is a content of B ₂ O ₃ of 16.9% by weight. And extends below a limit line 1002 indicating a TiO ₂ content of 4.0 wt%. From this, it is clear that the tendency of separation increases with an increase in the B ₂ O ₃ content and the TiO ₂ content.

1 shows a so-called backlight having a light-shielded area according to the invention. A basic form of a reflective base plate, support plate and substrate plate for a small backlight device is shown. 1 shows a backlight device having external electrodes. 1 shows a display device having a fluorescent lamp attached to the side. A diaphragm showing the course of the limit line at which turbidity occurs for various temperatures and processing durations.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Center part 12.1 ... Open end 12.2 ... Open end 14.1 ... Metal wire 14.2 ... Metal wire 110 ... Fluorescent tube 130 ... Plate 150 ... Depression 160 ... Reflective layer 202 ... Display 210 ... Fluorescence Tube 250 ... Light transmission type plate 310 ... Light emitting unit 315 ... Molded disk 330a ... External electrode 330b ... External electrode 360.1 ... Radiation space 360.2 ... Radiation space 360.3 ... Radiation space 360.4 ... Radiation space 360.5 ... Radiation space 380 ... Barrier 410 ... Cover disc

Claims (39)

A method of turbidizing a glass, wherein the glass composition comprises the following ingredients in weight percent:
SiO ₂ 55~85 weight%
B ₂ O ₃ > 0 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
TiO ₂ > 1.0-10 wt%,
The method wherein the glass is subjected to a thermal aftertreatment after melting, the thermal aftertreatment being performed such that the glass separates into at least two phases and has turbidity.   For thermal post-treatment, the glass is cooled from the melt to the holding temperature or heated from room temperature to the holding temperature in the first process step, and the cooling rate to the holding temperature is such that the glass becomes turbid as desired. The method of claim 1, wherein the method is selected to exhibit a degree σ> 0.1.   3. A method according to claim 2, characterized in that the time is in the range> 1 second to 60 minutes, preferably> 50 seconds to 30 minutes, more preferably more than 100 seconds to 30 minutes.   The holding temperature T is in the range of Tg + 50 ° C. <T <Tg + 500 ° C., preferably in the range of Tg + 50 ° C. <T <Tg + 400 ° C., and more preferably in the range of Tg + 50 ° C. <T <Tg + 200 ° C. The method according to 2 or 3.   5. A method according to any one of claims 2 to 4, characterized in that the glass is cooled from a holding temperature to a temperature below this holding temperature and preferably at room temperature.   6. The method of claim 5, wherein the cooling rate used to cool to a temperature below the holding temperature is greater than 20 K / h. The glass composition includes the following components:
SiO ₂ 60~75 weight%
B ₂ O ₃ > 5 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight
CaO 0-20% by weight
SrO 0-5% by weight
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
ZnO 0-3 wt%
ZrO ₂ 0 to 5% by weight
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1.0% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ⁻ 0 to 2% by weight, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is in the range of> 1.0 to 10% by weight, and the glass is PdO + PtO ₃ in a total amount of 0.00001% to 0.1% by weight. _{+ PtO 2 + PtO + RhO 2} + Rh 2 O 3 + IrO having a content of 2 + _Ir 2 _{O 3,} the method according to any one of claims 1 to 6. The glass composition has a TiO ₂ content in the range of more than 1.0 wt.% To 8 wt.%, Preferably more than 2 wt.% To 7 wt.%, More preferably more than 3 wt.% To 6 wt. The method according to claim 1, comprising: 9. Process according to any one of claims 1 to 8, characterized in that ΣTiO ₂ + B ₂ O ₃ is in the range of 5 to 35% by weight, preferably in the range of 10 to 25% by weight. The method according to claim 1, wherein the glass composition includes the following components.
SiO ₂ 60~85 weight%
B ₂ O ₃ 0-10% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 5-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight,
ΣMgO + CaO + SrO + BaO 3-20% by weight,
ZnO 0-8% by weight,
ZrO 0-5% by weight,
TiO ₂ > 1.0-10 wt%,
Fe ₂ O ₃ 0 to 5% by weight,
CeO ₂ 0-5% by weight,
MnO ₂ 0-5% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
PbO 0-5% by weight
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1, 0 to 10% by weight, provided that
ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ is 0.1% by weight,
And _SO ⁴ 2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ⁻ 0 to 2% by weight. The glass composition, the TiO _2, up to 8% by weight greater than 1.0 wt%, preferably up to 7% by weight more than 2% by weight, is quite preferably up to 6 wt% more than 3 wt% The method according to claim 10, comprising a range.   The glass produced by the method according to claim 1, wherein the glass has turbidity.   The glass tube containing glass produced by the method according to claim 1, wherein the glass tube has turbidity.   The flat glass containing the glass produced by the method according to claim 1, wherein the flat glass has turbidity. A light emitting means having a glass body, particularly a fluorescent lamp, wherein the glass of the glass body has a glass composition comprising the following components:
SiO ₂ 55~85 weight%
B ₂ O ₃ > 0 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0 to 5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
TiO ₂ > 1.0-10 wt%,
The light emitting means, wherein the glass body is at least partially turbid. Said glass composition comprises TiO ₂ in a range of more than 1.0 to 8% by weight, preferably more than 2% by weight to 7% by weight, quite preferably more than 3% by weight to 6% by weight. The light-emitting means according to claim 15. The glass composition comprises TiO ₂ and B ₂ O ₃ and ΣTiO ₂ + B ₂ O ₃ is in the range of 5 to 35% by weight, preferably in the range of 10 to 25% by weight. The light emitting means according to 16   The light emitting means according to any one of claims 15 to 17, wherein the glass body has a scattering power σ> 0.1, preferably σ> 0.4, in at least one region having turbidity. , Especially fluorescent lamps. The glass composition of the glass of the glass body is
SiO ₂ 60~75 weight%
B ₂ O ₃ > 18 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
ZnO 0-3 wt%,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1.0% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2 wt%, provided that
ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight, and the glass is PdO + PtO ₃ + PtO ₂ + PtO + RhO in a total amount of 0.00001 to 0.1% by weight. The light emitting means according to claim 15, comprising a content of ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ . The glass composition of the glass of the glass body is
SiO ₂ 60~85 weight%
B ₂ O ₃ 0-10% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 5-25% by weight,
ZrO ₂ 0 to 5% by weight
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0 to 5% by weight,
CeO ₂ 0-5% by weight,
MnO ₂ 0-5% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
PbO 0-5% by weight
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
However, ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight,
ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ is 0.1% by weight,
And _SO ⁴ 2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2% by weight
The light-emitting means according to claim 15, comprising:   The light emitting means is a gas discharge lamp, the gas discharge lamp is a fluorescent lamp, and the fluorescent lamp is an EEFL lamp, an LCD display, a computer monitor, a telephone display, and an illumination device for a display. Item 21. The light emitting means according to any one of Items 15 to 20.   The light-emitting means according to any one of claims 15 to 21, wherein the light-emitting means is turbid in the first part and sufficiently transparent in at least the second part.   23. The light emitting means according to claim 22, wherein the light emitting means has a plurality of electrical bushings, and these bushings are provided in the region of the second portion. A glass tube manufactured from glass, wherein the glass composition has the following components:
SiO ₂ 55~85 weight%
B ₂ O ₃ > 0 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
TiO ₂ > 1.0-10% by weight,
The glass tube is at least partially turbid. The glass composition has a TiO ₂ content in the range of more than 1.0 to 8% by weight, preferably more than 2% by weight to 7% by weight, more preferably more than 3% by weight to 6% by weight. 25. A glass tube according to claim 24, comprising: 26. The glass composition comprises TiO ₂ and B ₂ O ₃ and ΣTiO ₂ + B ₂ O ₃ is in the range of 5 to 35% by weight, preferably in the range of 10 to 25% by weight. The glass tube as described in. The runnable glass body has a scattering power σ> 0.1, preferably σ> 0.4, in at least one region having turbidity. The glass tube as described in. The glass composition of the glass of the glass tube is:
SiO ₂ 60~75% by weight,
B ₂ O ₃ > 18 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
ZnO 0-3 wt%,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1.0% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2% by weight,
However, ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight, and the glass is PdO + PtO ₃ + PtO in a total amount of 0.00001 to 0.1% by weight. _{2 + PtO + RhO 2 + Rh} 2 O 3 + IrO 24 claims, characterized in that it comprises a content of 2 + _Ir 2 _{O 3} to 27 glass tube according to any one of the. The glass composition of the glass of the glass tube is:
SiO ₂ 60~85% by weight,
B ₂ O ₃ 0-10% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20 wt%, but ΣLi ₂ O + Na ₂ O + K ₂ O 5-25 wt%,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0 to 5% by weight, provided that ΣMgO + CaO + SrO + BaO 3 to 20% by weight,
ZnO 0-8% by weight,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0 to 5% by weight,
CeO ₂ 0-5% by weight,
MnO ₂ 0-5% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
PbO 0-5% by weight
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
However, ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight, and ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ % By weight
And _SO ⁴ 2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2% by weight,
The glass tube according to any one of claims 24 to 28, comprising: The light emitting means is a part of a gas discharge lamp, the gas discharge lamp is a fluorescent lamp, and the fluorescent lamp is an EEFL lamp, an LCD display, a computer monitor, a telephone display, and an illumination device for the display. The glass tube according to any one of claims 24 to 29.
Light emitting means.   The glass tube according to any one of claims 24 to 30, wherein the glass tube has turbidity in the first portion and is sufficiently transparent in at least the second portion. It is a flat glass manufactured from glass, and the glass composition has the following components:
SiO ₂ 55~85% by weight,
B ₂ O ₃ > 0 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
TiO ₂ > 1.0-10% by weight,
The flat glass is characterized in that the flat glass is at least partially turbid. The glass composition comprises more than 1.0% by weight of TiO ₂ to 8%, preferably more than 2% by weight to 7% by weight, and most preferably more than 3% by weight to 6% by weight. The flat glass according to claim 32, characterized in that: The glass composition contains TiO ₂ and B ₂ O ₃ and ΣTiO ₂ + B ₂ O ₃ is in the range of 5 to 35 wt%, preferably in the range of 10 to 25 wt%. Flat glass as described in 2.   35. The flat glass according to any one of claims 32 to 34, characterized in that it has a scattering power [sigma]> 0.1, preferably [sigma]> 0.4, in at least one region having turbidity. Flat glass. The glass composition of the flat glass is
SiO ₂ 60~75% by weight,
B ₂ O ₃ > 18 to 35% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 0-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 0-20% by weight,
ZnO 0-3 wt%,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0-0.5 wt%,
CeO ₂ 0 to 0.5% by weight,
MnO ₂ 0 to 1.0% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
SO ₄ ^2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2% by weight,
However, ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight, and the glass is PdO + PtO ₃ + PtO in a total amount of 0.00001 to 0.1% by weight. The flat glass according to any one of claims 32 to 35, which has a content of ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ . The glass composition of the flat glass is
SiO ₂ 60~85% by weight,
B ₂ O ₃ 0-10% by weight,
Al ₂ O ₃ 0-10% by weight,
Li ₂ O 0-10% by weight,
Na ₂ O 0-20 weight,
K ₂ O 0-20% by weight, provided that
ΣLi ₂ O + Na ₂ O + K ₂ O 5-25% by weight,
MgO 0-8% by weight,
CaO 0-20% by weight,
SrO 0-5% by weight,
BaO 0-5% by weight, provided that
ΣMgO + CaO + SrO + BaO 3-20% by weight,
ZnO 0-8% by weight,
ZrO ₂ 0-5% by weight,
TiO ₂ > 1.0 to 10% by weight
Fe ₂ O ₃ 0 to 5% by weight,
CeO ₂ 0-5% by weight,
MnO ₂ 0-5% by weight,
Nd ₂ O ₃ 0-1.0% by weight,
WO ₃ 0~2% by weight,
Bi ₂ O ₃ 0-5% by weight,
MoO ₃ 0-5% by weight,
0-5 wt% PbO,
As ₂ O ₃ 0 to 1% by weight,
Sb ₂ O ₃ 0 to 1% by weight,
However, ΣFe ₂ O ₃ + CeO ₂ + TiO ₂ + PbO + AS ₂ O ₃ + Sb ₂ O ₃ is at least 1.0 to 10% by weight, and ΣPdO + PtO ₃ + PtO ₂ + PtO + RhO ₂ + Rh ₂ O ₃ + IrO ₂ + Ir ₂ O ₃ % By weight
And _SO ⁴ 2-0 to 2% by weight,
Cl ^- 0 to 2 wt%,
F ^- 0 to 2% by weight,
The flat glass according to any one of claims 32 to 36, comprising:   The flat glass is a part of a gas discharge lamp, the gas discharge lamp is a fluorescent lamp, and the fluorescent lamp is an EEFL lamp, an LCD display, a computer monitor, a telephone display, and an illumination device for the display. The flat glass according to any one of claims 32 to 37.   The flat glass according to any one of claims 32 to 38, wherein the flat glass has turbidity in the first portion and is sufficiently transparent in at least the second portion.

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