JP2003048749A - Uv absorbing filter glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass for an UV absorbing filter which sufficiently blocks rays at about 418 nm and blue light at a longer wavelength than the above wavelength. SOLUTION: The glass material contains Cu, I, SnO and one or more halogens selected from F, Cl and Br.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet absorbing filter glass used for liquid crystals and the like, which sharply cuts ultraviolet rays and visible rays having a short wavelength close to ultraviolet rays. More specifically, it is used for liquid crystal, etc.
The present invention relates to an ultraviolet absorbing filter glass capable of sharply blocking light rays up to a blue color.

[0002]

2. Description of the Related Art At present, light sources containing ultraviolet rays are used in many fields. For example, a liquid crystal projector uses a lamp for a light source including ultraviolet rays, such as a high pressure mercury lamp, a halogen discharge tube, a xenon discharge tube. However, since ultraviolet rays and visible light with a short wavelength close to ultraviolet rays are harmful to the life of the liquid crystal element, these light rays are protected by an ultraviolet absorbing glass filter etc. so that the liquid crystal element is not exposed to ultraviolet rays or visible light with a short wavelength close to ultraviolet rays. Need to shut off. Therefore, there has been a demand for a sharp cut filter that blocks and cuts the ultraviolet rays and visible light having a wavelength close to the ultraviolet rays, and that does not impair the amount of other visible light as much as possible.

As such a filter, a sharp cut filter in which copper chloride or copper bromide is added to a glass material is known, and has been used as a light source of a liquid crystal projector. However, this filter has a limit of a half-value absorption wavelength (a wavelength exhibiting absorption half of the maximum absorption) of 418 nm, and it is not possible to sufficiently cut a light beam having a wavelength of about 418 nm and a blue light having a longer wavelength than that. As a result, it has been found that the use of this filter damages the liquid crystal and shortens the life of the liquid crystal. Therefore, there has been a demand for a filter capable of sharply cutting blue light having a longer wavelength.

[0004]

DISCLOSURE OF THE INVENTION The inventor of the present invention relates to a glass for an ultraviolet absorption filter used in a liquid crystal projector or the like, that is, a glass for an ultraviolet absorption filter, which is a light beam of about 418 nm or a blue light having a wavelength longer than that. As a result of earnestly studying to develop a material that can be sufficiently cut and does not impair other visible light amount as much as possible, Cu, Cl or Br is added to the glass material.
The present invention has been completed by finding that the above object can be achieved by adding I together with halogen such as Sn and SnO.

[0005]

That is, the present invention provides C
The present invention provides an ultraviolet absorbing filter glass characterized by using a glass material containing at least one halogen selected from u, I, SnO and F, Cl and Br. The present invention further provides, in claim 9, Cu, I, S
Provided is a method for producing an ultraviolet absorbing filter glass, which comprises subjecting a glass material containing at least one halogen selected from nO and F, Cl and Br to a glass state, and then subjecting it to a high temperature heat treatment.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The ultraviolet absorbing filter of the present invention
The glass material used for the lath is usually SiO₂, B₂O
₃, Al₂O₃, Li₂O, Na₂O, K₂O, BaO, Zr
O₂Is included. In addition, the ultraviolet absorption of the present invention
The glass material used for the collection filter glass is Cu,
From I, halogens other than I, that is, F, Cl and Br
At least one selected, and containing SnO
Characterize. The halogens of I, Cl and Br are usually C
Combined with u, CuI₂, CuBr₂, CuCl₂Etc.
It is contained in the ultraviolet absorbing filter glass of the present invention.
However, as described later, part of the halogen is NaC.
Alkali halide such as 1, KCl, KBr, NaI
Contained as a group and / or alkaline earth metal halide
It may be. Especially, for the total weight of the glass material, S
iO₂25-65% by weight, B₂O₃5-30% by weight,
Al₂O₃1-20% by weight, Li₂0.5-10 weight of O
%, Na ₂1-25% by weight of O, K₂1-25% by weight of O,
1-15% by weight of BaO, ZrO ₂0.5-8 weight
%, CuI₂0.01-0.3% by weight, CuBr₂To
0.1-2 wt%, CuCl₂0.01-0.3 weight
% And SnO 0.1-3 wt% are preferable.
It is used well.

The glass material used in the ultraviolet absorbing filter glass of the present invention further includes MgO, CaO and Zn.
It may contain O. The respective contents are 0.1-15% by weight of MgO and CaO with respect to the total weight of the glass material.
0.1-15 wt% and ZnO 0.1-15 wt%
Is preferred. The glass material used for the ultraviolet absorption filter glass of the present invention usually further contains an alkali metal halide and / or an alkaline earth metal halide. As the alkali metal halide, NaC
1, KCl, KBr, NaI and the like. The content of these is preferably in the range of 0.1 to 0.3% by weight with respect to the total amount of glass.

The glass material used for the ultraviolet absorbing filter glass of the present invention is characterized by using a copper compound of halogen other than I in combination with copper iodide, and as a result, it is possible to sharpen blue light having a wavelength longer than about 418 nm. Can be cut into For example, when copper chloride, copper bromide and copper iodide are combined, copper chloride has the effect of suppressing the formation of copper colloid, and copper bromide and copper iodide are copper bromide colloid and copper iodide colloid. And makes a large blue absorption, 418n
Even blue light with a wavelength longer than about m can be sharply cut. The contents of CuI ₂ , CuBr ₂ and CuCl ₂ are 0.01 to 0.3% by weight and 0.
The range of 3-2% by weight and 0.01-0.1% by weight is preferable. For example, when copper chloride is added in an amount of 0.3% by weight or more, absorption of copper ions appears. When the content of copper bromide is less than 0.3% by weight, a copper bromide colloid may not be produced. The amount of copper iodide added is 0.01-0.
In the range of 1%, it contributes to the formation of blue-absorbing copper iodide colloid, but if more is added, copper colloid is easily absorbed,
It may absorb blue and green and the glass may turn red.

SnO is necessary to form copper halides. As described above, the content of SnO in the glass material is preferably 1-3% by weight, but if it exceeds 0.5% by weight, the copper colloid may grow rapidly and the filter may turn red. Therefore, 0.1 is more preferable.
-0.5% by weight.

B ₂ O ₃ is the main glass component next to SiO ₂ ,
A more preferable content is 15 with respect to the total weight of the glass material.
It is about -30%. When it is 15% or more, melting of the glass is facilitated, and when it is 30% or less, water resistance of the glass is improved. Al ₂ O ₃ , Zr
O ₂ strengthens the water resistance and acid resistance of the glass, so it is preferable to contain O _{2 at} about 1-20 wt% and 0.5-8 wt%, respectively. Li ₂ O, which is an alkaline component, is preferably contained in an amount of about 0.5-10% by weight, and more preferably 1-3% by weight, in order to facilitate melting of glass. The content of Na ₂ O is preferably 1 to 25% by weight, but more preferably 1 to 5% by weight in order to prevent absorption of CuO. K ₂ O has an effect of suppressing the absorption of CuO, and its content is preferably 1 to 25% by weight, but in order to prevent the growth of copper colloid, the range of 1 to 10% by weight is more preferable.

The total content of Li ₂ O, Na ₂ O and K ₂ O is preferably 20% by weight or less based on the total amount of glass. Within this range, a copper halide colloid is likely to be produced. ZnO component of alkaline earth is B
It has a stronger reducing property than aO and is likely to form a copper colloid, but as described above, it may be contained if it is 15% by weight or less based on the total amount of glass. Similarly, MgO and CaO are also 15% by weight.
You may contain if it is the following ranges.

In the glass material used for the ultraviolet absorbing filter glass of the present invention, SiO ₂ , B ₂ O ₃ , Al ₂
O ₃ , Li ₂ O, Na ₂ O, K ₂ O, BaO, ZrO ₂ , C
uI ₂ , CuBr ₂ , CuCl ₂ and SnO compounds, as well as MgO, CaO, ZnO and NaCl, KCl, KB
Compounds such as r and NaI are usually mixed in a glass state, but some of them do not necessarily exist as independent compound molecules.

The ultraviolet absorbing filter glass of the present invention comprises
For example, it can be manufactured as follows. SiO
₂, B₂O₃, Ai₂O₃, Li₂O, Na₂O, K₂O, Mg
O, CaO, BaO, ZnO, ZrO₂Lord of glass etc.
A component or a compound that produces them in the process of manufacturing glass,
For example H₃BO₃, Na₂B_FourO₇, Al (OH)₃, Li₂
CO₃, K ₂CO₃, BaCO₃Carbonate compounds and hydroxides
Etc., SnO, and further CuI₂, CuBr₂, CuCl₂
Such as copper halide or glass during the manufacturing process
Compounds formed, such as copper compounds and NaCl, KCl,
Alkali metal halides or halogens such as KBr and NaI
Alkaline earth metal etc.
Melts at about 30 ° C. CuI₂, CuCl₂, CuBr
₂Is a compound of copper and halogen in glass materials.
It may be added or other forms, such as copper compounds and N
Alkali halides such as aCl, KCl, KBr and Nal
Added as remetal or alkaline earth metal halide, etc.
They may be produced during the glass manufacturing process. part
Is a compound of halogen with copper, and the others are compounds other than copper
It may be added. For example, CuBr₂And KC
l, added as KI, Cu in the glass manufacturing process
I₂, CuCl₂May be generated. Molten glass
Is poured into a mold and subjected to various post-treatments such as removing strain after cooling.
Then, an ultraviolet absorbing filter glass is obtained.

As described above, the glass material is completed through the steps of melting, molding, slow cooling, etc., but the ultraviolet absorbing filter glass of the present invention is preferably further subjected to high temperature heat treatment. By this high temperature heat treatment, the transmission characteristic curve of glass can be moved to the long wavelength side,
Blue light can be cut more effectively. This high temperature heat treatment is preferably 2 at 500-700 ° C.
Although it is a heat treatment for about 0 to 100 minutes, the glass material has already undergone a heat history in the process of completion such as melting, forming, and gradual cooling steps, so the optimum treatment conditions for the high temperature heat treatment may vary depending on the manufacturing lot. different. Further, the optimum processing conditions differ depending on the desired light absorption edge and the movement width of the transmittance curve, but basically, the transmittance curve moves to a longer wavelength side as the processing time increases at a high temperature. However, since excessive heat treatment causes copper colloid to grow and the absorption at 580 nm becomes large, more preferably at 550 to 650 ° C,
The processing time is about 20-90 minutes. By appropriately combining the processing temperature and the processing time, the light absorption edge is 0.1 nm while maintaining flat transmission characteristics in the visible region.
Can be managed with the accuracy of. In this way, a filter having a half-value absorption wavelength of 430 nm can be manufactured while maintaining flat transmission characteristics in the visible region.

[0015]

EXAMPLES The present invention will be described below with reference to examples, but these examples do not limit the scope of the present invention.

[Example 1] SiO ₂ (M-SiO ₂ ) 4
8.7 parts by weight, H ₃ BO ₃ 23.1 parts by weight, Na ₂ B ₄ O
₇ 11.4 parts by weight, NaCl 0.1 part by weight, NaI
0.1 part by weight, Al (OH) ₃ 13.3 parts by weight, L
i ₂ CO ₃ 5.2 parts by weight, K ₂ CO ₃ 8.4 parts by weight, B
6.2 parts by weight of aCO ₃ , 3.8 parts by weight of ZrO ₂ , Sn
0.5 parts by weight of O and 1.2 parts by weight of CuBr ₂ were mixed and melted at 1250 to 1430 ° C. in an electric furnace. In the process of melting the raw materials and forming glass, H ₃ BO ₃ and Al (O
H) ₃ desorbs water to form B ₂ O ₃ and Al ₂ O ₃ , respectively. Carbon dioxide is desorbed from Li ₂ CO ₃ , K ₂ CO ₃ and BaCO ₃ to produce Li ₂ O, K ₂ O and BaO, respectively. Na ₂ B ₄ O ₇ decomposes into B ₂ O ₃ and Na ₂ O. Therefore, the composition in the obtained glass material is the composition described in Table 1. In addition, CuBr ₂ , NaCl, N
A part of aI reacts to form CuI ₂ , CuCl ₂ or NaBr. The molten glass was poured into carbon, hand-pressed, rapidly cooled, and strained in a cooling furnace to obtain two samples. The thickness of the sample was 1.5 mm. One of the samples was heat-treated in an electric furnace at a temperature of 520 ° C. for 30 minutes. The spectral characteristics are shown in FIG. Another sample was heat-treated in an electric furnace at a temperature of 620 ° C. for 30 minutes. This spectral characteristic is also shown in FIG. The half cut absorption wavelength of the sharp cut filter glass thus obtained is 4
It was 30 nm.

[0017]

[Table 1]

Example 2 Except that the glass composition was changed.
Same as Example 1. The composition in the obtained glass material is as shown in Table 2, and further, CuBr ₂ ,
Part of NaCl and NaI react to react with CuI ₂ , CuCl ₂
It also forms NaBr. In this way the thickness is 1.5 mm
2 samples were obtained. One of the samples was heat-treated in an electric furnace at a temperature of 520 ° C. for 30 minutes. The spectral characteristics are shown in FIG. Another sample was heat-treated in an electric furnace at a temperature of 620 ° C. for 30 minutes. This spectral characteristic is also shown in FIG. The half cut absorption wavelength of the sharp cut filter glass thus obtained was 430 nm.

[0019]

[Table 2]

[0020]

The ultraviolet absorbing filter glass of the present invention maintains flat transmission characteristics in the visible region,
It is possible to obtain an absorption wavelength of about 430 nm as a half-value absorption wavelength, and it is possible to sufficiently cut blue light having a longer wavelength as compared with a conventional ultraviolet absorption filter glass having a maximum absorption wavelength of about 418 nm. Further, by vapor-depositing an antireflection coat or an ultraviolet reflection coat on this filter glass having a half-value absorption wavelength of 430 nm, stronger ultraviolet rays can be effectively cut and aging is unlikely to occur. As a result, it is possible to effectively cut off ultraviolet rays and visible light having a short wavelength close to ultraviolet rays, which are harmful to the life of the liquid crystal element, so that the liquid crystal is protected and the color reproducibility of the projection screen is not impaired. And a device using a lamp for a light source including ultraviolet rays such as a high pressure mercury lamp, a halogen discharge tube, a xenon discharge tube,
For example, it can be suitably used for a liquid crystal projector or the like.

[Brief description of drawings]

FIG. 1 shows the transmittance curve of the sample obtained in Example 1.

2 is a graph showing the transmittance curve of the sample obtained in Example 2. FIG.

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Claims (10)

[Claims] 1. Cu, I, SnO and F, Cl and Br
An ultraviolet-absorbing filter glass comprising a glass material containing at least one halogen selected from the group consisting of: 2. SiO based on the total weight of the glass material₂To
25-65% by weight, B₂O₃5-30% by weight, Al₂O₃
1-20% by weight, Li₂0.5-10 wt% O, Na
₂1-25% by weight of O, K₂1-25% by weight of O and BaO
1-15% by weight, ZrO₂0.5-8% by weight, CuI₂
0.01-0.3% by weight, CuBr ₂0.1-2 layers
%, CuCl₂0.01-0.3 wt% and SnO
0.1 to 3% by weight is contained.
UV absorption filter glass. 3. 0.1 to 15% by weight of MgO and C
3. The ultraviolet absorption filter glass according to claim 2, which contains 0.1-15% by weight of aO and 0.1-15% by weight of ZnO. 4. The ultraviolet absorbing filter glass according to claim 1, which contains an alkali metal halide and / or an alkaline earth metal halide. 5. B ₂ O _{3 in an amount} of 15 to 30% by weight and Li ₂ O in an amount of 1
-3% by weight, 1-5% by weight of Na ₂ O, 1-10% by weight of K ₂ O and 0.1-0.5% by weight of SnO. Absorption filter glass. 6. The ultraviolet absorbing filter glass according to claim 1, wherein the glass material is a glass material which has been completed in a glass state and then subjected to a high temperature heat treatment. 7. The ultraviolet absorbing filter glass according to claim 6, wherein the high temperature heat treatment is a heat treatment at 550 to 700 ° C. for 20 to 100 minutes. 8. The liquid crystal display device according to claim 1, which is for liquid crystal.
UV absorption filter glass of No. 7 to No. 7. 9. Cu, I, SnO and F, Cl and Br
A method for producing an ultraviolet-absorbing filter glass, which comprises subjecting a glass material containing at least one halogen selected from the following to a glass state and then subjecting it to a high-temperature heat treatment. 10. The method for producing an ultraviolet absorbing filter glass according to claim 9, wherein the high temperature heat treatment is a heat treatment at 550 to 700 ° C. for 20 to 100 minutes.