RU2280625C1 - Color filter glass - Google Patents

Abstract

FIELD: glassmaking industry.

SUBSTANCE: invention provides color filter glass for use in optic-laser instrumentation engineering for filters absorbing in UV spectrum region, which glass contains following components, wt %: PbO 63.5-78,39, TeO₂ 5.0-27,4, GeO₂ 3.0-13.0, B₂O₃ 6.0-9.05, La₂O₃ 0.01-0.1. Glass is characterized by refraction factor >1.8 and linear expansion factor 110-115 x 10^-7 K^-1. Glass synthesis temperature is 900-950°C.

EFFECT: achieved complete nontransparence in UV region and up to 400 nm with sharp edge in optical absorbance and increased light transmission in wavelength range 450-500 nm.

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Description

The invention relates to compositions of optical glasses and is intended for the manufacture of filters that are opaque in the ultraviolet region of the spectrum.

Known glass for light filters, containing in wt.%: SiO ₂ 99.1-99.97; Al ₂ O ₃ 0.01-0.5; Eu ₂ O ₃ 0.01-0.3; TiO ₂ 0.01-0.1 [1]. Glass is opaque in the short-wave ultraviolet region of the spectrum in the wavelength range of 160-200 nm. The disadvantage of glass is light transmission in the UV region of the spectrum in the wavelength range of 200-400 nm, and therefore it cannot be used for filters that absorb in this wavelength range.

Closest to the proposed glass for a light filter in terms of technical nature and the achieved result is glass containing in wt.%: SiO ₂ 99.5-99.97; Al ₂ O ₃ 0.01-0.1; TiO ₂ 0.01-0.1; GeO ₂ 0.01-0.3 [2].

Glass provides complete opacity in the short-wave ultraviolet region of the spectrum in the wavelength range of 160-220 nm, has minimal transparency in the UV region up to 300 nm and is transparent in the visible (400-700 nm) region of the spectrum. The disadvantage of glass is that it does not provide complete absorption in the wavelength range of 220-400 nm (light transmission at 300 nm is 8-15%, at 400 nm - 65-80%), which does not allow the use of the specified glass as a cut-off filter UV spectrum. In addition, glass is melted at a very high temperature - 1920-1940 ° C, which requires high energy consumption and special synthesis conditions.

The task of the invention is to ensure complete absorption in the UV region of the spectrum up to 400 nm, increase light transmission in the wavelength range of 450-500 nm and reduce the temperature of glass synthesis.

To solve this problem, we propose glass for a light filter, including PbO, TeO ₂ , GeO ₂ , B ₂ O ₃ , La ₂ O ₃ , which contains these components in the following ratio, wt.%: PbO 63.5-78.39; TeO ₂ 5.0-27.4; GeO ₃ 3.0-13.0; In ₂ O _3, 6.0-9.05; La ₂ O ₃ 0.01-0.1.

The quantitative ratio of these components in the proposed glass composition provides complete absorption in the wavelength range up to 400 nm, which allows you to create filters that cut off the UV region of the spectrum, increases light transmission in the wavelength range of 450-500 nm and reduces the temperature of glass synthesis to 900-950 ° FROM.

From literature sources, glass for light filters of such a chemical composition for solving this problem is unknown and we propose for the first time.

A mixture for cooking glass is prepared from the following raw materials: lead minium, tellurium dioxide, germanium dioxide, boric acid and lanthanum oxide. Raw materials are weighed on a technical scale, mixed thoroughly, sieved through a No. 0.5 sieve and poured into corundum crucibles, which are loaded into a cold electric oven. Glass is melted at a temperature of 900–950 ° С with a holding time of 30–35 min until complete penetration and clarification of the glass melt. The rate of temperature rise in the furnace is 300 ° C per hour.

Specific compositions and properties of the proposed glasses and prototype, as well as their spectral transmittance are presented in tables 1 and 2.

Compositions and properties of glasses

Table 1 Components and Features The content of components in the compositions, wt.% glass one 2 3 Prototype [2] Pbo 63.5 72.9 78.39 - TeO ₂ 27.4 5,0 9.3 - GeO ₂ 3.0 13.0 5,0 - B ₂ O ₃ 6.0 9.05 7.3 - La ₂ o ₃ 0.1 0.05 0.01 - SiO ₂ - - - 99.5-99.97 Al ₂ About ₃ - - - 0.01-0.1 TiO ₂ - - - 0.01-0.1 CeO ₂ - - - 0.01-0.3

Continuation of table 1 Synthesis temperature, ° С 900-950 900-950 900-950 1920-1940 Softening start temperature, ° С 350 345 320 - The linear expansion temperature coefficient in the range of 20-220 ° C, α · 10 ⁷ K ^-1 115 110 one hundred - Refractive index > 1.9 > 1.9 > 1.9 -

table 2
Spectral transmission of glasses Light transmission coefficient,% Wavelength nm one 2 3 Prototype [2] 160 0 0 0 0 200 0 0 0 0 220 0 0 0 0 300 0 0 0 8-10 350 0 0 0 - 400 0 0 0 73-80 450 72 75 82 - 500 88 90 90 83-85

Comparing the spectral characteristics of the proposed glass and the prototype, we can conclude that the proposed glass is opaque in a wide wavelength range of the UV region of the spectrum (160-400 nm), has increased transmission in the wavelength range of 450-500 nm, has a sharp edge of optical absorption and synthesized at significantly low temperatures (900-950 ° C).

Complete absorption by the glass of the UV region of the spectrum in the presence of a sharp edge of optical absorption allows us to produce filters that cut off the UV region of the spectrum. The low cooking temperature provides energy-saving glass synthesis technology.

The proposed glass for light filters is recommended for use in optical laser instrumentation.

Information sources

1. A.S. USSR No. 441246, IPC ³ C 03 C 3/06, publ. 08/30/74. Bull. Number 32.

2. A.S. USSR No. 923975, IPC ³ S 03 S 3/06, publ. 04/30/82. Bull. No. 16 (prototype).

Claims (1)

Glass for filters that absorb the UV region of the spectrum up to 400 nm, including PbO, TeO ₂ , GeO ₂ , B ₂ O ₃ , La ₂ O ₃ in the following ratio of components, wt.%: Pbo 63.5-78.39 TeO ₂ 5.0-27.4 GeO ₂ 3.0-13.0 B ₂ O ₃ 6.0-9.05 La ₂ o ₃ 0.1-0.01