JPS6025377B2 - Glass for cathode ray tubes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to glass for cathode ray tubes, and in particular to a recently developed glass composition suitable for red color in cathode ray tubes for light sources used to display color images on stadium scoreboards, outdoor billboards, etc. Regarding.

A color image system using a cathode ray tube as a light source uses red, green, and blue phosphors coated on the inner surface of each glass bulb, and uses an electron beam to emit red, green, and blue monochromatic light. A plurality of these pixels are arranged in a grid to form one pixel, forming a large color image plane.

The cathode ray tube glass bulb for this light source easily transmits the red, green, and blue wavelength light rays emitted from the phosphor, but other wavelengths, such as sunlight at twilight, are easily transmitted to the human eye. It is desirable that yellow light, which is most felt and gives off a sense of broadness, be sufficiently absorbed to clearly reproduce the colors red, green, and blue.

For this purpose, glass bulbs are used which are colored red, green and blue, corresponding to the emission spectra of the red, green and blue phosphors. The present invention resides in such cathode ray tube glass,
It is specifically intended to provide a threaded glass for the red color.

Conventionally, cadmium mu selenium colored glass has been known as red glass. However, a light source cathode ray tube bulb made of red glass has the disadvantage that even when no light is being emitted, the reflection of external light makes it appear to the human eye as if it were emitting red light, reducing the contrast of the image. . Moreover, this cadmium-mooselenium-colored red glass is difficult to manufacture because it poses a pollution problem due to the toxicity of the cadmium component. The present invention has selective transmission-absorption characteristics in the visible wavelength range, transmits light in the red wavelength range sufficiently, absorbs yellow light sufficiently, and is not affected by external light reflection. Another object of the present invention is to provide glass for cathode ray tubes having optical properties that enable clear images with high contrast and brightness to be obtained.

By the way, in a cathode ray tube, a high operating voltage is applied to generate X-rays and electron beams, so the glass bulb has the ability to absorb X-rays, and also has the ability to absorb X-rays and electron beams for a long period of time. It is necessary that the color be browned by electron beam irradiation and that no discoloration that would result in a decrease in transmittance occurs.

An object of the present invention is to provide a cathode ray tube glass suitable for red light, which has high X-ray absorption ability and high resistance to browning due to X-rays and electron beams, and also has the above-mentioned optical properties. do. The present invention employs a glass with high X-ray absorption ability and low browning due to X-rays and electron beams as the base glass, and in order to impart the necessary optical properties to this glass, it also contains N03 and Mn○. It has been discovered that by adding an appropriate amount, a glass particularly suitable for use in cathode ray tubes for light sources can be obtained.

The color tone of the glass of the present invention is eight-tone reddish-purple. The cathode ray tube glass according to the present invention has Si02 of 50 to 7 in weight percent.
5%, AI203 0.5-3%, Ca0 0-4%,
Mg0 0-2%, Sr0 0-12%, 0-1
0%, POO O~3%, Zn0 0~3%, Zr02
0-3%, Li20 0-4%, Na20 3-15
%, K200~10%, Ti02 0~2%, Ce02
1.5-3%, N also 03 3-10%, Pr2031
．． 5-5%, Mn0 0.05-2.0%, Fe203
Consisting of 0 to 0.2%, provided that Sr○〇Ba0+POO
+Zn○×Zr02=5~25%, Na20×K20=
It is 5-20%. The attached drawings show examples of the ships described below.
Transmittance curve of the glass of the present invention listed in 1 (thickness of glass:
2 ribs).

With reference to this transmittance curve, N4 in the glass of the present invention
The meaning of the inclusion of the 03 component and the Mn◯ component will be explained. NMo03 increases the transmittance for red light compared to blue and green light, and significantly reduces the transmittance for yellow light.

That is, it has high transmission characteristics in the wavelength range of 600 to 73, which represents the red light of the spectrum, and sharp absorption characteristics in the wavelength range of 570 to 60, which represents the yellow light of the spectrum. Mn0 reduces the transmittance of 430 to 56 skin in the spectrum including blue light and green light, while maintaining the high transmission property for red light and the sharp absorption property for yellow light due to the above-mentioned N03.

Therefore, red light appears stronger overall,
Demonstrates high achromatic properties against red light. In the present invention,
By containing N03 and Mn0 as described above, a cathode ray tube glass having preferable optical characteristics of selective transmission and absorption is obtained.

Next, the reason why the glass composition range is limited as described above in the present invention will be explained.

SiO2 is a major glass-forming oxide that is contained in large amounts, but if it exceeds 75%, solubility and processability deteriorate.
If it is less than 50%, the expansion coefficient will be too large and the chemical durability of the glass will be poor.

Ayu 203 has the effect of improving the chemical durability of glass, but if it is less than 0.5%, this effect cannot be obtained.
If it exceeds 3%, the glass becomes poorly soluble and bubbles are difficult to break. Ca○ and Mg0 have the effect of improving the chemical durability of glass, but when Ca04% and Mg02% are exceeded, the glass tends to devitrify. Sr○, Ba0, PO○, Zn
○, Z(]2 is contained in a total amount of 5 to 25% in order to provide the glass with high X-ray absorption ability,
If it exceeds 12% of S, 10% of sheer, 3% of Zn, and 23% of Zr, the meltability will deteriorate and devitrification will easily occur, and if it exceeds 3% of Pb, it will turn brown when exposed to X-rays or electron beams. It becomes easier to do. Li20 has the effect of improving the meltability of glass, but if it exceeds 4%, the expansion coefficient becomes too large and the strain point becomes too low. Na2
0, K20 is effective for improving the meltability of glass and adjusting the expansion coefficient of glass, but Na201
If it exceeds 5%, K2010% and Na20+K2020%, the chemical durability and electrical insulation properties of the glass will deteriorate, while if it is less than Na203%, K201% and Na20+K205%, the meltability will deteriorate and devitrification will occur easily. At the same time, the strain point of the glass becomes too high, resulting in poor workability.
Tj02 and Ce02 are added because they have the effect of preventing browning of the glass due to X-rays or electron beams, and their amounts are set to 22% or less of Ti0 and 1.5% to 3% of Ce02. If Ce02 is less than 1.5%, the above-mentioned effect will not be exhibited, while if it exceeds Ti022% or Ce023%, the glass will become unfavorably colored and will tend to devitrify. As previously explained with reference to the attached drawings, Nd203 is a component that imparts high transmission characteristics for red light and sharp absorption characteristics for yellow light to glass, and for this purpose, 3% or more is required. If it exceeds 10%, the transmittance of the wavelength range of red light, which requires high transmission characteristics, will decrease, and the melting properties of the glass will deteriorate, making it easy to cause devitrification, which is not preferable. As mentioned earlier, Mn0 is a component that reduces the transmittance in the wavelength range of blue light and green light and relatively improves the color rendering properties of red light, and for this purpose, Mn0 is
．． If the content exceeds 2%, it will affect the wavelength transmittance of red light, resulting in a decrease in it. Pr203 usually contains two of them in the raw material of Nd203.
It is a component contained in an amount of 5% or less, and the above-mentioned N
also has the same effect as 03 and can be added up to 5% to give the glass the desired transmission-absorption characteristics, but 1.5%
If the amount is less than that, the desired effect will not be obtained. Fe20
3 has the same effect as Mn○, reducing the transmittance of blue and green light wavelengths, but when it exceeds 0.2%, it interacts with MnO and causes browning due to sunlight's ultraviolet rays, i.e. , it becomes easier to cause solarization,
Degrades the optical properties of glass. Also, N et al.03, Pr2
2030~2% as a normal impurity in 03, Sm
There is no problem even if 2030 to 2% is included.

Examples of glasses according to the invention are shown in the table below.

Table of Examples As explained above, the glass of the present invention has an optical property of transmitting light in the red wavelength range sufficiently higher than light in other wavelength ranges, so it has excellent color rendering properties for red light. Furthermore, since the light does not appear to be emitting light due to reflection of external light when it is not emitting light, a clear image can be obtained.

Further, the glass of the present invention has high X-ray absorption ability, and
There is also little deterioration in transmittance due to browning due to X-rays and electron beams. The glass of the present invention having such various characteristics,
It is especially suitable as a red color glass for cathode ray tubes for light sources.

[Brief explanation of the drawing]

The drawing shows a transmittance curve of a cathode ray tube glass according to the present invention.

Claims (1)

[Claims] 1 Consists of ▲Mathematical formulas, chemical formulas, tables, etc.▼, provided that SrO+BaO+PbO+ZnO+Zr
O_2=5-25%, Na_2O+K_2O=5-20
% cathode ray tube glass.