INFRARED-TRANSMITTING GLASS

Abstract

Provided is a thermally stable and inexpensive infrared-transmitting glass. An infrared-transmitting glass contains, in terms of % by mole, over 0 to 9% Ge, over 0 to 50% Ga, 50 to 90% Te, 0 to 40% Si+Al+Ti+Cu+In+Sn+Bi+Cr+Sb+Zn+Mn+Cs+Ag+As+Pb, and 0 to 40% F+Cl+Br+I.

Claims

1. An infrared-transmitting glass containing, in terms of % by mole, over 0 to 9% Ge, 18 to 50% Ga, 50 to 90% Te, 0 to 40% Si+Al+Ti+Cu+In+Sn+Bi+Cr+Sb+Zn+Mn+Cs+Ag+As+Pb, and 0 to 40% F+Cl+Br+I.

2. An optical element in which the infrared-transmitting glass according to claim 1 is used.

3. An infrared sensor in which the optical element according to claim 2 is used.

Description

EXAMPLES

[0031] Hereinafter, the present invention will be described with reference to examples, but is not limited to these examples.

[0032] Tables 1 and 2 show Examples of the present invention and a Comparative Example.

TABLE-US-00001 TABLE 1 1 2 3 4 5 8 7 8 9 Glass Composition Ge 5 5 7 9 3 1 4 4 1 (% by mole) Ga 10 18 10 2 7 4 22 27 32 Ag 5 2 10 18 7 8 Sn 3 1 2 I 3 6 9 Te 80 75 73 71 83 87 68 62 56 Vitrification good good good good good good good good good Internal Transmittance good good good good good good good good good

TABLE-US-00002 TABLE 2 10 11 12 13 14 15 16 17 18 Glass Composition Ge 1 1 2 5 1 2 1 2 15 (% by mole) Gs 37 42 45 6 4 2 1 1 Ag 14 23 28 33 37 45 Sn 9 6 7 2 I 2 1 3 15 20 18 8 8 Te 51 50 50 60 52 50 50 50 40 Vitrification good good good good good good good good poor Internal Transmittance good good good good good good good good

[0033] Each sample in Examples 1 to 17 and Comparative Example 18 was prepared in the following manner. A quartz glass ampoule was evacuated with the application of heat and a raw material batch formulated to give each glass composition shown in the tables was then put into the quartz glass ampoule. Next, the quartz glass ampoule was sealed with an oxygen burner. Thereafter, the sealed quartz glass ampoule was raised in temperature to 650 to 1000 C. at a rate of 10 to 40 C./hour in a melting furnace and then held for six to twelve hours. During the holding time, the quartz glass ampoule was turned upside down to stir the melt. Subsequently, the quartz glass ampoule was taken out of the melting furnace and rapidly cooled to room temperature, thus obtaining a sample.

[0034] Each of the obtained samples was subjected to X-ray diffraction and, based on its diffraction spectrum, whether the sample became vitrified was confirmed. In the tables, vitrified samples are represented to be good, whereas unvitrified samples are represented to be poor.

[0035] Furthermore, each sample was measured in terms of internal transmittance. With regard to the internal transmittance for each sample, the sample polished with a thickness of 2 mm0.1 mm and the sample polished with a thickness of 10 mm0.1 mm were each measured in terms of transmittance including surface reflectance loss and their internal transmittances at a wavelength of 8 to 14 m were calculated from the obtained measured values. Samples having an average internal transmittance of 80% or more are represented to be good, whereas samples having an average internal Ftransmittance of less than 80% are represented to be poor.

[0036] As shown in the tables, the samples in Examples 1 to 17 were confirmed to become vitrified. Furthermore, these samples had an internal transmittance as high as 80% or more at a wavelength of 8 to 14 m and thus exhibited good infrared transmission properties.

[0037] On the other hand, the sample in Comparative Example 18 was not vitrified and its internal transmittance at a wavelength of 8 to 14 m could not be measured.

INDUSTRIAL APPLICABILITY

[0038] The infrared-transmitting glass according to the present invention is suitable as a cover member for protecting a sensor part of an infrared sensor or an optical element, such as a lens, for focusing infrared light on an infrared sensor part of the infrared sensor.