JP3154323B2 - UV transparent black glass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention also relates to an ultraviolet transmitting black glass that selectively transmits only near ultraviolet light.

[0002]

2. Description of the Related Art Special glass, which blocks visible light and transmits ultraviolet light, is used as a filter for utilizing only ultraviolet light, and is formed into a tube or bulb to be used as an envelope of a mercury lamp called a black light. . Examples of such glasses include those described in JP-B-48-8722 and JP-A-63-248738. Each of these glasses contains Co or an oxide of Co and Ni, and absorbs visible light by its inherent absorption.

The glass described in JP-B-48-8722 is based on a borosilicate glass so that it can be used for the envelope of a high-pressure black light, and contains CoO.
1-5% by weight, NiO 0.1-4% by weight, CoO + N
Ultraviolet transparent black glass having high thermal shock resistance containing 2 to 7% by weight of iO. In Japanese Patent Publication No. 48-8722, Table 1 shows a conventional typical ultraviolet-transmitting black glass other than the borosilicate glass. Since all of these glasses are for black light, 36
It has a transmission characteristic of transmitting a wavelength around 5 nm well and blocking visible light.

The glass described in Japanese Patent Application Laid-Open No. 63-248738 is an alkali silicate glass transmitting 280 to 500 nm and having improved solarization resistance to ultraviolet irradiation. In this glass, PbO and Sn
By containing O ₂ or Ce ⁴⁺ , Ti ⁴⁺ , Fe ³⁺ , and V ⁵⁺ , the absorption edge is shifted to the longer wavelength side to reduce the solarization of the glass.

[0005]

In recent years, studies have been conducted on the effects of ultraviolet rays of the sun on biological systems. In ground-based observations, the intensity of ultraviolet rays from the sun suddenly becomes zero at around 300 nm, but ultraviolet rays from artificial light sources such as discharge lamps are observed up to around 200 nm.
It is known that ultraviolet rays of up to 300 nm are absorbed in the upper layer of the atmosphere. For this reason, an ultraviolet sensor that detects only ultraviolet rays from the sun in a terrestrial environment is used in the research. A photodiode represented by a silicon photodiode is used as a light receiving element of this ultraviolet sensor. However, since the photodiode itself has sensitivity over a wide wavelength range, it is necessary to cut off unnecessary light rays.
315-400nm corresponding to ultraviolet light observed on the ground
There is a need for a filter that transmits only light.

Therefore, an attempt has been made to apply a conventionally known ultraviolet transmitting black glass as a filter for this solar ultraviolet sensor, but there were the following problems, and an appropriate one could not be obtained.

[0007] The glass according to the invention described in Japanese Patent Publication No. 48-8722 mentioned above is all 30
Since it transmits light in a range from less than 0 nm to more than 400 nm, it is not suitable for the intended use. Glass B described in Table 1 of Japanese Patent Publication No. 48-8722 has transmission characteristics in a substantially desired range, but has a maximum transmittance of only about 50%, and has a problem in sensitivity.

The glass described in Japanese Patent Application Laid-Open No. 63-248738 is also difficult to apply because it transmits light in the range of 280 to 500 nm and has a high transmittance on the long wavelength side of 700 nm or more. .

[0009] There are other glasses having similar transmittance characteristics, but if it is attempted to cut a wavelength of 315 nm or less while maintaining a certain transmittance similarly to the above-mentioned glasses, the transmission range shifts to the longer wavelength side. In many cases, light having a wavelength of 400 nm or more is transmitted. In order to obtain a filter that transmits only 315 to 400 nm using conventional glass, it is conceivable to increase the amount of the coloring agent to narrow the transmission range. However, in this method, the transmittance is reduced as a whole. Therefore, the disadvantage accompanied by the decrease in sensitivity cannot be eliminated.

In this type of filter, a change in transmittance due to the solarization of the glass directly affects the detection sensitivity. Therefore, a glass that does not cause the solarization has been demanded.

The present invention has been made in view of such circumstances, and provides a glass that cuts visible light and ultraviolet light of 315 nm or less and transmits ultraviolet light of 315 to 400 nm and is hardly deteriorated in transmittance. The purpose is to:

[0012]

According to the present invention, in order to achieve the above object, 0.2 to 3% by weight of CoO, NiO by 100% by weight of a base glass transparent to ultraviolet rays.
4.5 to 15% , except for CoO + NiO 5 to 18% ,
_{CeO 2 0~1%, TiO 2 0.01~3} %, provided that C
eO ₂ + TiO ₂ containing 0.01 to 3%, CeO ₂ / T
The mass ratio of iO ₂ is less than 50.

The glass of the present invention has a wavelength of 315 to 4
It is characterized by selectively transmitting 00 nm ultraviolet rays.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The glass of the present invention contains CoO and NiO as essential components in order to completely absorb visible light. Since it is difficult for one of these components to completely absorb visible light, it is necessary to use both of them. When both components are less than the above lower limits, absorption of visible light is incomplete, and when added in excess of the respective upper limits, devitrification tends to occur and the maximum transmittance decreases.

If the total amount of CoO and NiO is less than 2%, light near 400 nm is transmitted, and if it exceeds 18%, the maximum transmittance near 365 nm becomes too low, and cobalt ions acting as network modifying ions And the amount of nickel ions is too large, and the glass tends to be devitrified, which is not preferable. A preferred range is that the CoO is 0.5 to
1.5%, NiO is 4.5 to 15%, more preferably 6.5 to 12%, and the total amount is 5 to 15%, more preferably 8%.
~ 12%.

CeO ₂ and TiO ₂ are used as ultraviolet absorbers. Although TiO ₂ may be used alone, the combined use of CeO ₂ has an effect of sharply cutting the short wavelength side.

If the TiO ₂ content is less than 0.01%, a necessary ultraviolet absorbing effect cannot be obtained, and if it exceeds 3%, 365 n
The transmittance around m is too low. This tendency is the same even when CeO ₂ is used in combination, and CeO ₂ and Ti
If the total amount of O ₂ exceeds 3%, the transmittance in the desired wavelength range becomes too low, which is not preferable. Preferably the upper limit is 2%
The following is assumed. Also, if CeO ₂ is added in excess of 1%,
Since the TiO ₂ content must be relatively reduced in order to maintain the desired transmission characteristics, CeO ₂ / Ti described below will be used.
The mass ratio of O ₂ exceeds 50, and the transmittance around 365 nm is reduced.

CeO ₂ and As ₂ O known as a fining agent
_{When 3} is used in combination, solarization tends to occur. Therefore, when CeO ₂ is used, As ₂ O is used.
It is said that it is preferable not to use ₃ as much as possible, but in the present invention, sufficient solarization resistance can be obtained even when As ₂ O ₃ is used.

TiO ₂ has an action of preventing solarization as well as an ultraviolet absorber, and is an essential component in the present invention. However, it has been found that there is a difference in how solarization occurs in relation to the CeO ₂ content. did. That is, when the mass ratio of CeO ₂ / TiO ₂ contained in the glass is less than 50, the deterioration with respect to the ultraviolet irradiation is small,
If it exceeds 50, the tendency of deterioration due to ultraviolet rays increases, and the initial characteristics of the filter cannot be maintained over a long period of use.

It should be noted that adding a Cu, V, Rh oxide as a coloring agent other than the above in order to adjust the absorption edge on the short wavelength side can be used as long as the desired characteristics are not impaired.

Since the heat resistance is not so important for the above-mentioned ultraviolet sensor for the base glass composition constituting the glass of the present invention, a soft glass such as soda-lime glass having a good melting property can be used as a base. In particular, when heat resistance is required, hard glass such as borosilicate glass may be used. In other words, the basic glass used in the present invention is a glass that does not contain a component that inhibits transmission in the ultraviolet region,
The desired transmission characteristics can be imparted by adding the above components.

Accordingly, the glass according to the present invention is prepared by weighing and mixing the above components with a known glass material constituting an ultraviolet-transmissive glass so as to have a predetermined ratio, melting the mixture, sufficiently stirring and refining the mixture, It can be obtained by molding into a shape suitable for the application and cooling. Since the melting conditions vary depending on the base glass composition, appropriate conditions are selected and performed.

[0023]

Embodiments of the present invention will be described below. Table 1 shows Examples of the present invention, Comparative Examples without CeO ₂ and TiO ₂ , and those with a mass ratio of CeO ₂ / TiO ₂ exceeding 50. In addition, the composition in a table | surface is shown by the mass%.

The raw materials of these glasses are weighed and mixed so as to have the compositions shown in the table, and the mixed materials are placed in a platinum crucible.
The mixture was heated at a temperature of 1450 ° C. in an oxidizing atmosphere and melted for 4 hours, sufficiently stirred and clarified, and then cast into a mold to form a glass block. After this was slowly cooled, a thin plate was sliced and polished to a thickness of 1 mm to obtain a sample.

The spectral transmittance of the obtained sample was measured. 1 and Comparative Sample No. 1 12
Is shown in FIG. Note that the samples of other examples are also No. The transmittance characteristics were almost the same as those of Sample No. 1.

After measuring the transmittance, each sample was subjected to 40
At a distance of 30 cm from a 0 W mercury lamp, 200
After irradiating with a time ray, the transmittance was measured again, and the extent of decrease in the transmittance at the peak wavelength before and after the ultraviolet irradiation was investigated. The results are shown in Table 1 as "Transmittance decrease width".

As shown in the transmittance curve of FIG. 1, the sample of the comparative example transmits light in a range of less than 300 nm to more than 400 nm, whereas the sample of the example according to the present invention transmits light of a wavelength range of 315 to 400 nm. Is transmitted at a transmittance of 60% or more, and the visible region of 400 to 700 nm can be completely absorbed and blocked. This is an ideal characteristic as a filter for a solar ultraviolet sensor, and has the advantage that the characteristic can be realized with a thinness of 1 mm. In order to obtain the transmission and absorption characteristics shown in FIG.
O must be contained at 4.5% or more, and the total amount of NiO and CoO must be 5% or more. However, when the amount of the coloring agent added is small, the thickness of the sample can be increased so that the desired transmission and absorption characteristics can be obtained.

Also, the "permeability decrease width" shown in Table 1 is 1.1% at the maximum in the sample of the embodiment according to the present invention, whereas the transmittance of the comparative example is 3.8% or less. 5.5
%, Which indicates that the glass of the present invention is excellent in the effect of preventing solarization by ultraviolet irradiation.

As is clear from Table 1, these transmission characteristics and solarization resistance are unchanged regardless of whether the base glass is a soft glass such as an alkali silicate glass or a hard glass such as a borosilicate glass. can get. Therefore, it is possible to select and respond to the basic glass composition in accordance with the characteristics required depending on the use and the use environment, such as heat resistance, chemical durability, moldability, and the like.

The glass of the present invention is not limited to the above-mentioned solar light / ultraviolet sensor, but may be used for an envelope for black light, a filter for an ultraviolet ray inspection device, or the like as long as the characteristics are acceptable. it can.

[0031]

[Table 1]

[Table 1]

As described above, according to the present invention, CoO, NiO, CeO ₂ , TiO _2
2 is contained in a predetermined amount so that visible light and 315
An ultraviolet ray of 315 nm or less and an ultraviolet ray of 315 to 400 nm can be transmitted, and an ideal transmittance as a filter for a solar ultraviolet ray sensor can be obtained with a small thickness.

Further, the glass of the present invention has an excellent effect of preventing solarization caused by irradiation with ultraviolet rays, and thus has an effect of maintaining the initial transmission characteristics for a long period of time even in applications exposed to ultraviolet rays.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. 1 and Comparative Example N
o. It is a curve figure which shows the spectral transmittance of 12 samples.

[Description of References] 1 No. 1 spectral transmittance 2 Comparative Example No. 1 12 spectral transmittance

Claims (2)

(57) [Claims] 1. A base glass 100 transparent to ultraviolet rays.
CoO 0.2 to 3% by mass%, Ni
O 4.5 to 15% , provided that CoO + NiO 5 to 18
% , CeO ₂ 0 to 1%, TiO ₂ 0.01 to 3%, but containing CeO ₂ + TiO ₂ 0.01 to 3%, CeO ₂
/ Ultraviolet transmission black glass mass ratio of TiO ₂ is equal to or less than 50. 2. The ultraviolet-transparent black glass according to claim 1, wherein the ultraviolet ray having a wavelength of 315 to 400 nm is selectively transmitted.