U.S. patent application number 16/630880 was filed with the patent office on 2020-05-14 for chalcogenide glass material.
The applicant listed for this patent is NIPPON ELECTRIC GLASS CO., LTD.. Invention is credited to Yoshimasa MATSUSHITA, Fumio SATO.
Application Number | 20200148575 16/630880 |
Document ID | / |
Family ID | 65232374 |
Filed Date | 2020-05-14 |
![](/patent/app/20200148575/US20200148575A1-20200514-D00001.png)
United States Patent
Application |
20200148575 |
Kind Code |
A1 |
MATSUSHITA; Yoshimasa ; et
al. |
May 14, 2020 |
CHALCOGENIDE GLASS MATERIAL
Abstract
Provided is a small-diameter chalcogenide glass material having
excellent weather resistance and mechanical strength and being
suitable as an optical element for an infrared sensor. The
chalcogenide glass material has an unpolished side surface, a
pillar shape with a diameter of 15 mm or less, and a composition
of, in terms of % by mole, 40 to 90% S+Se+Te and an inside of the
glass material is free of stria with a length of 500 .mu.m or
more.
Inventors: |
MATSUSHITA; Yoshimasa;
(Otsu-shi, JP) ; SATO; Fumio; (Otsu-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIPPON ELECTRIC GLASS CO., LTD. |
Otsu-shi, Shiga |
|
JP |
|
|
Family ID: |
65232374 |
Appl. No.: |
16/630880 |
Filed: |
June 28, 2018 |
PCT Filed: |
June 28, 2018 |
PCT NO: |
PCT/JP2018/024619 |
371 Date: |
January 14, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C03C 3/321 20130101;
C03B 19/02 20130101; C03B 23/047 20130101; C03C 4/10 20130101; G01J
5/08 20130101; G02B 1/00 20130101; C03B 2201/86 20130101 |
International
Class: |
C03B 23/047 20060101
C03B023/047; C03C 3/32 20060101 C03C003/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2017 |
JP |
2017-149788 |
Claims
1. A chalcogenide glass material having an unpolished side surface,
a pillar shape with a diameter of 15 mm or less, and a composition
of, in terms of % by mole, 40 to 90% S+Se+Te, an inside of the
glass material being free of stria with a length of 500 .mu.m or
more.
2. The chalcogenide glass material according to claim 1, wherein
the side surface is a fire-polished surface.
3. The chalcogenide glass material according to claim 1,
containing, in terms of % by mole, over 0 to 50% Ge+Ga+Sb+As.
4. The chalcogenide glass material according to claim 1,
containing, in terms of % by mole, 0 to 40% Ge+Ga and 0 to 45%
Sb+As.
5. A method for producing a chalcogenide glass material, the method
comprising drawing a glass base material containing, in terms of %
by mole, 40 to 90% S+Se+Te by a redraw process.
6. The method for producing a chalcogenide glass material according
to claim 5, wherein a drawing temperature is equal to or lower than
a glass transition point of the chalcogenide glass material plus
100.degree. C.
7. The method for producing a chalcogenide glass material according
to claim 5, wherein the drawing is performed in a vacuum or in an
inert atmosphere.
8. An optical element using the chalcogenide glass material
according to claim 1.
9. An infrared sensor using the optical element according to claim
8.
Description
TECHNICAL FIELD
[0001] The present invention relates to chalcogenide glass
materials for use in infrared sensors, infrared cameras, and so
on.
BACKGROUND ART
[0002] Vehicle-mounted night vision devices, security systems, and
the like include infrared sensors for use to detect living bodies
at night. To sense infrared rays with wavelengths of about 8 to 14
.mu.m emitted from living bodies, such an infrared sensor is
provided, in front of the sensor part, with an optical element,
such as a filter or a lens, capable of transmitting infrared rays
in the above wavelength range.
[0003] Examples of a material for the optical element as described
above include Ge, Zn, and Se. These materials are crystalline
bodies and therefore have poor processability, which makes them
difficult to process into complicated shapes, such as an aspheric
lens. For this reason, these materials have the problem of making
mass production of the above optical element difficult and also
have the problem of making size reduction of the infrared sensor
difficult.
[0004] To cope with the above, chalcogenide glasses are proposed as
vitreous materials that can transmit infrared rays with wavelengths
of about 8 to 14 .mu.m and are relatively easily processable (see,
for example, Patent Literature 1).
[0005] Recently, a small-diameter chalcogenide glass has been
desired for the purpose of further size reduction of infrared
sensors.
CITATION LIST
Patent Literature
[0006] [PTL 1] JP-A-2009-161374
SUMMARY OF INVENTION
Technical Problem
[0007] However, a small-diameter chalcogenide glass has poor
weather resistance and mechanical strength. Furthermore, when the
chalcogenide glass is used as an optical element for an infrared
sensor, there arises a problem that an image is distorted or
disturbed.
[0008] The present invention has been made in view of the above
situations and, therefore, has an object of providing a
small-diameter chalcogenide glass material having excellent weather
resistance and mechanical strength and being suitable as an optical
element for an infrared sensor.
Solution to Problem
[0009] The inventors have conducted various studies, consequently
have made the following findings, and have proposed the present
invention based on the findings. A small-diameter chalcogenide
glass material is typically produced by cutting and polishing. When
the side surface of the chalcogenide glass is polished, microscopic
polishing flaws are formed in the side surface, so that the
specific surface area of the side surface increases. As a result,
the area of contact of the chalcogenide glass with outside air
increases and, therefore, the weather resistance becomes likely to
decrease. Furthermore, small defects called Griffith flaws are
produced by the polishing process, so that the mechanical strength
becomes likely to decrease. Meanwhile, when producing a
small-diameter chalcogenide glass material, striae are likely to be
produced in the glass material. If there is a large-sized stria in
the chalcogenide glass material, images from the infrared sensor
are likely to be distorted or disturbed.
[0010] A chalcogenide glass material according to the present
invention is a chalcogenide glass material having an unpolished
side surface, a pillar shape with a diameter of 15 mm or less, and
a composition of, in terms of % by mole, 40 to 90% S+Se+Te, an
inside of the glass material being free of stria with a length of
500 .mu.m or more.
[0011] Since the side surface is unpolished, the specific surface
area is reduced, which makes the weather resistance likely to be
increased, and no Griffith flaw decreasing the mechanical strength
is produced, which makes the mechanical strength likely to be
increased. Furthermore, since there is no stria with a length of
500 .mu.m or more in the glass material, images from an infrared
sensor are less likely to be distorted or disturbed.
[0012] In the chalcogenide glass material according to the present
invention, the side surface is preferably a fire-polished surface.
Since the side surface is formed into a fire-polished surface, the
specific surface area is further reduced, so that the weather
resistance and mechanical strength are more likely to be
increased.
[0013] The chalcogenide glass material according to the present
invention preferably contains, in terms of % by mole, over 0 to 50%
Ge+Ga+Sb+As.
[0014] The chalcogenide glass material according to the present
invention preferably contains, in terms of % by mole, 0 to 40%
Ge+Ga and 0 to 45% Sb+As.
[0015] A method for producing a chalcogenide glass material
according to the present invention includes drawing a glass base
material containing, in terms of % by mole, 40 to 90% S+Se+Te by a
redraw process. Since the glass base material is redrawn, an
unpolished, small-diameter chalcogenide glass can be easily
obtained.
[0016] In the method for producing a chalcogenide glass material
according to the present invention, a drawing temperature is
preferably equal to or lower than a glass transition point of the
chalcogenide glass plus 100.degree. C. Since the drawing
temperature is equal to or lower than the glass transition point of
the chalcogenide glass plus 100.degree. C., the evaporation of the
glass components can be reduced, so that striae are less likely to
be produced.
[0017] In the method for producing a chalcogenide glass material
according to the present invention, the drawing is preferably
performed in a vacuum or in an inert atmosphere. Since the drawing
is performed in a vacuum or in an inert atmosphere, the evaporation
of the glass components can be further reduced, so that striae are
even less likely to be produced.
[0018] An optical element according to the present invention uses
the above-described chalcogenide glass material.
[0019] An infrared sensor according to the present invention uses
the above-described optical element.
Advantageous Effects of Invention
[0020] The present invention enables provision of a small-diameter
chalcogenide glass material having excellent weather resistance and
mechanical strength and being suitable as an optical element for an
infrared sensor.
BRIEF DESCRIPTION OF DRAWINGS
[0021] FIG. 1 is a photograph showing the inside of a sample
obtained in Example 1.
[0022] FIG. 2 is a photograph showing the inside of a sample
obtained in Comparative Example 1.
DESCRIPTION OF EMBODIMENTS
[0023] A chalcogenide glass material according to the present
invention has an unpolished side surface and, particularly, the
side surface is preferably a fire-polished surface. If the side
surface is polished, the specific surface area of the side surface
increases, so that the reaction with oxygen and moisture in the air
is promoted, which makes the weather resistance likely to be
decreased. Furthermore, small defects called Griffith flaws are
produced by the polishing process, so that the mechanical strength
is likely to be decreased. If a polishing step is included in the
production process, a problem of cost rise also arises.
[0024] The chalcogenide glass material according to the present
invention has a pillar shape and its diameter is 15 mm or less,
preferably 10 mm or less, and particularly preferably 5 mm or less.
If the diameter is too large, this makes it difficult to reduce the
size of an infrared sensor. Although no particular limitation is
placed on the lower limit of the diameter, it is realistically 1 mm
or more.
[0025] The chalcogenide glass material according to the present
invention is free of stria with a length of 500 .mu.m or more. Even
if there are striae in the chalcogenide glass material, their
lengths are less than 500 .mu.m, preferably 200 .mu.m or less, more
preferably 100 .mu.m or less, still more preferably 50 .mu.m or
less, and particularly preferably 10 .mu.m or less. By doing so,
when the chalcogenide glass material is used as an optical element,
the reduction in resolution of an image due to distortion or
disturbance can be prevented.
[0026] The chalcogenide glass material according to the present
invention contains, in terms of % by mole, 40 to 90% S+Se+Te.
Reasons why the glass composition is limited as just described will
be described below. Note that in the following description of the
contents of components "%" refers to "% by mole" unless otherwise
specified.
[0027] Chalcogen elements, S, Se, and Te, are components for
forming the glass network. The content of S+Se+Te (the total amount
of S, Se, and Te) is 40 to 90%, preferably 50 to 80%, more
preferably 50 to 65%, and particularly preferably 55 to 65%. If the
content of S+Se+Te is too small, vitrification becomes difficult.
On the other hand, if the content of S+Se+Te is too large, the
glass components are likely to evaporate during melting and
redrawing, which is likely to cause striae.
[0028] The chalcogenide glass material may contain, in addition to
the above components, the various components mentioned below.
[0029] Ge, Ga, Sb, and As are components that widen the
vitrification range and increase the thermal stability of glass.
Ge+Ga+Sb+As (the total amount of Ge, Ga, Sb, and As) is preferably
over 0 to 50%, more preferably 10 to 45%, still more preferably 15
to 43%, yet still more preferably 20 to 43%, even still more
preferably 25 to 43%, and particularly preferably 30 to 43%. If the
content of Ge+Ga+Sb+As is too large, vitrification becomes
difficult.
[0030] Ge+Ga (the total amount of Ge and Ga) is preferably 0 to
40%, more preferably 2 to 35%, still more preferably 4 to 33%, yet
still more preferably 4 to 30%, even still more preferably 4 to
28%, and particularly preferably 4 to 25%. Sb+As (the total amount
of Sb and As) is preferably 0 to 45%, more preferably 5 to 40%,
still more preferably 10 to 35%, yet still more preferably 15 to
35%, and particularly preferably 20 to 35%.
[0031] The chalcogenide glass material having the above composition
is likely to exhibit a glass transition point of 100 to 400.degree.
C., 120 to 380.degree. C., or particularly 140 to 360.degree.
C.
[0032] Next, a description will be given of a method for producing
a chalcogenide glass material according to the present invention.
The chalcogenide glass material according to the present invention
can be produced by Production Method 1 below.
[0033] (Production Method 1)
[0034] Raw materials are mixed to give the above-described glass
composition, thus obtaining a raw material batch. Next, a quartz
glass ampoule is evacuated with the application of heat, the raw
material batch is then put into the quartz glass ampoule, and the
quartz glass ampoule is sealed with an oxygen burner while being
evacuated. Note that the diameter of the quartz glass ampoule is
preferably 15 mm or more, more preferably 17 mm or more, and
particularly preferably 20 mm or more. If the diameter of the
quartz glass ampoule is too small, a melt is difficult to move in
the quartz glass ampoule, so that a stirring effect cannot
sufficiently be obtained and striae are therefore likely to be
produced.
[0035] Next, the sealed quartz glass ampoule is raised in
temperature to 650 to 1000.degree. C. at a rate of 10.degree. C. to
20.degree. C./hour in a melting furnace and then held for six to
twelve hours. During the holding time, the quartz glass ampoule is
turned upside down as necessary to stir the melt.
[0036] Subsequently, the quartz glass ampoule is taken out of the
melting furnace and rapidly cooled to room temperature, thus
obtaining a glass base material. Thereafter, the quartz glass
ampoule is cut and the glass base material is taken out of the
ampoule.
[0037] When the obtained glass base material is drawn by a redraw
process, a pillar-like chalcogenide glass material having a smaller
diameter can be obtained. The side surface of the chalcogenide
glass material produced by the redraw process is a fire-polished
surface, which has excellent weather resistance and mechanical
strength.
[0038] The drawing temperature is preferably equal to or lower than
the glass transition point of the chalcogenide glass material plus
100.degree. C., more preferably equal to or lower than the glass
transition point of the chalcogenide glass material plus 80.degree.
C., still more preferably equal to or lower than the glass
transition point of the chalcogenide glass material plus 60.degree.
C., and particularly preferably equal to or lower than the glass
transition point of the chalcogenide glass material plus 40.degree.
C. If the drawing temperature is too high, the glass components
easily evaporate, so that striae are likely to be produced and the
refractive index of the inside of the glass material is likely to
be uneven. The atmosphere in which the drawing is performed is
preferably a vacuum or an inert atmosphere. The preferred inert
atmosphere is nitrogen, argon or helium atmosphere. Particularly
preferred is a nitrogen atmosphere because of its inexpensiveness.
If the drawing is performed without controlling the atmosphere,
components in the chalcogenide glass material react with oxygen in
the air, so that the evaporation of glass components is promoted.
For example, in the case of a sulfide-based chalcogenide glass
material containing much sulfur, sulfur in the glass material
reacts with oxygen, so that SO.sub.2 evaporates from the surface of
the glass material. Thus, striae are likely to be produced and the
refractive index of the inside of the glass material is likely to
be uneven. In addition, the glass material may be oxidized, so that
its infrared transparency tends to decrease.
[0039] As alternatives to Production method 1, a chalcogenide glass
material may be produced by Production Method 2 or 3 below.
[0040] (Production Method 2)
[0041] Raw materials are mixed to give the above-described glass
composition, thus obtaining a raw material batch. Next, a quartz
glass ampoule is evacuated with the application of heat, the raw
material batch is then put into the quartz glass ampoule, and the
quartz glass ampoule is sealed with an oxygen burner while being
evacuated. Note that the diameter of the quartz glass ampoule is
the same as described above.
[0042] Next, the sealed quartz glass ampoule is raised in
temperature to 650 to 1000.degree. C. at a rate of 10.degree. C. to
20.degree. C./hour in a melting furnace and then held for six to
twelve hours. During the holding time, the quartz glass ampoule is
turned upside down as necessary to stir the melt.
[0043] Next, the quartz glass ampoule is taken out of the melting
furnace and the melt is poured into a mold in an inert atmosphere
and rapidly cooled to room temperature, thus obtaining a
chalcogenide glass material. Thereafter, the obtained chalcogenide
glass material may be drawn by a redraw process. The material for
the mold is preferably carbon or quartz glass . If a metallic mold
is used, it may react with the melt to form an alloy. Because the
diameter of the chalcogenide glass material depends on the inner
diameter of the mold, the inner diameter of the mold should be
selected according to the diameter of a chalcogenide glass material
to be produced.
[0044] (Production Method 3)
[0045] Raw materials are mixed to give the above-described glass
composition, thus obtaining a raw material batch. Next, a quartz
glass ampoule is evacuated with the application of heat, the raw
material batch is then put into the quartz glass ampoule, and the
quartz glass ampoule is sealed with an oxygen burner while being
evacuated. The quartz glass ampoule preferably has a shape in which
a glass forming portion for glass formation with an inner diameter
of 15 mm or less is connected to a stirring portion for stirring
with an inner diameter of 15 mm or more. Thus, during stirring, the
melt flows into the stirring portion and thus can easily move in
the quartz glass ampoule. Note that the inner diameter of the glass
forming portion should be selected according to the diameter of a
chalcogenide glass material to be produced.
[0046] Next, the sealed quartz glass ampoule is raised in
temperature to 650 to 1000.degree. C. at a rate of 10.degree. C. to
20.degree. C./hour in a melting furnace and then held for six to
twelve hours. During the holding time, the quartz glass ampoule is
turned upside down as necessary to stir the melt.
[0047] Subsequently, the quartz glass ampoule is taken out of the
melting furnace and the melt is moved to the glass forming portion
and rapidly cooled to room temperature, thus obtaining a
chalcogenide glass material.
[0048] Since the chalcogenide glass material according to the
present invention has excellent weather resistance and mechanical
strength and is free of stria of 500 .mu.m or more which may cause
image distortion or disturbance, it is suitable as an optical
element, such as a lens for focusing infrared light on an infrared
sensor part of an infrared camera.
EXAMPLES
[0049] Hereinafter, the present invention will be described with
reference to examples, but is not limited to the examples.
[0050] Tables 1 to 16 show Examples 1 to 180 according to the
present invention and Comparative Examples 1 and 2.
TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 11 12 Glass Ge
28.0 5.0 composition Ga (% by mole) Sb 12.0 33.0 As S 61.0 Se 60.0
Te Bi 1.0 Sn Glass transition point 278 230 (.degree. C.) Diameter
of glass base 15 15 15 15 21 30 15 15 15 15 21 30 material (mm)
Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0
11.0 13.0 glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00002 TABLE 2 Example 13 14 15 16 17 18 19 20 21 22 23 24
Glass Ge 22.0 33.0 composition Ga (% by mole) Sb As 20.0 12.0 S Se
58.0 55.0 Te Bi Sn Glass transition point 292 368 (.degree. C.)
Diameter of glass base 15 15 15 15 21 30 15 15 15 15 21 30 material
(mm) Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0
9.0 11.0 13.0 glass material (mm) Striae .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle.
TABLE-US-00003 TABLE 3 Example 25 26 27 28 29 30 31 32 33 34 35 36
Glass Ge 30.0 10.0 composition Ga (% by mole) Sb As 13.0 40.0 S Se
32.0 50.0 Te 25.0 Bi Sn Glass transition point 275 225 (.degree.
C.) Diameter of glass base 15 15 15 15 21 30 15 15 15 15 21 30
material (mm) Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0
3.0 5.0 7.0 9.0 11.0 13.0 glass material (mm) Striae .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle.
TABLE-US-00004 TABLE 4 Example 37 38 39 40 41 42 43 44 45 46 47 48
Glass Ge composition Ga (% by mole) Sb As 40.0 40.0 S 60.0 Se 60.0
Te Bi Sn Glass transition point 185 197 (.degree. C.) Diameter of
glass base 15 15 15 15 21 30 15 15 15 15 21 30 material (mm)
Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0
11.0 13.0 glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00005 TABLE 5 Example 49 50 51 52 53 54 55 56 57 58 59 60
Glass Ge composition Ga 20.0 8.2 (% by mole) Sb 27.7 As S 59.0 Se
Te 80.0 Bi Sn 5.1 Glass transition point 147 239 (.degree. C.)
Diameter of glass base 15 15 15 15 21 30 15 15 15 15 21 30 material
(mm) Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0
9.0 11.0 13.0 glass material (mm) Striae .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle.
TABLE-US-00006 TABLE 6 Example 61 62 63 64 65 66 67 68 69 70 71 72
Glass Ge 28.0 5.0 composition Ga (% by mole) Sb 12.0 33.0 As S 61.0
Se 60.0 Te Bi 1.0 Sn Glass transition point 278 230 (.degree. C.)
Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0
11.0 13.0 glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00007 TABLE 7 Example 73 74 75 76 77 78 79 80 81 82 83 84
Glass Ge 22.0 33.0 composition Ga (% by mole) Sb As 20.0 12.0 S Se
58.0 55.0 Te Bi Sn Glass transition point 292 368 (.degree. C.)
Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0
11.0 13.0 glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00008 TABLE 8 Example 85 86 87 88 89 90 91 92 93 94 95 96
Glass Ge 30.0 10.0 composition Ga (% by mole) Sb As 13.0 40.0 S Se
32.0 50.0 Te 25.0 Bi Sn Glass transition point 275 225 (.degree.
C.) Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0
9.0 11.0 13.0 glass material (mm) Striae .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle.
TABLE-US-00009 TABLE 9 Example 97 98 99 100 101 102 103 104 105 106
107 108 Glass Ge composition Ga (% by mole) Sb As 40.0 40.0 S 60.0
Se 60.0 Te Bi Sn Glass transition point 185 197 (.degree. C.)
Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0
11.0 13.0 glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00010 TABLE 10 Example 109 110 111 112 113 114 115 116 117
118 119 120 Glass Ge composition Ga 20.0 8.2 (% by mole) Sb 27.7 As
S 59.0 Se Te 80.0 Bi Sn 5.1 Glass transition point 147 239
(.degree. C.) Diameter of chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0
3.0 5.0 7.0 9.0 11.0 13.0 glass material (mm) Striae .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle.
TABLE-US-00011 TABLE 11 Example 121 122 123 124 125 126 127 128 129
130 131 132 Glass Ge 28.0 5.0 composition Ga (% by mole) Sb 12.0
33.0 As S 61.0 Se 60.0 Te Bi 1.0 Sn Glass transition point 278 230
(.degree. C.) Inner diameter of 15 15 15 15 21 30 15 15 15 15 21 30
stirring portion (mm) Inner diameter of 3.0 5.0 7.0 9.0 11.0 13.0
3.0 5.0 7.0 9.0 11.0 13.0 forming portion (mm) Diameter of
chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0 11.0 13.0
glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00012 TABLE 12 Example 133 134 135 136 137 138 139 140 141
142 143 144 Glass Ge 22.0 33.0 composition Ga (% by mole) Sb As
20.0 12.0 S Se 58.0 55.0 Te Bi Sn Glass transition point 292 368
(.degree. C.) Inner diameter of 15 15 15 15 21 30 15 15 15 15 21 30
stirring portion (mm) Inner diameter of 3.0 5.0 7.0 9.0 11.0 13.0
3.0 5.0 7.0 9.0 11.0 13.0 forming portion (mm) Diameter of
chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0 11.0 13.0
glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00013 TABLE 13 Example 145 146 147 148 149 150 151 152 153
154 155 156 Glass Ge 30.0 10.0 composition Ga (% by mole) Sb As
13.0 40.0 S Se 32.0 50.0 Te 25.0 Bi Sn Glass transition point 275
225 (.degree. C.) Inner diameter of 15 15 15 15 21 30 15 15 15 15
21 30 stirring portion (mm) Inner diameter of 3.0 5.0 7.0 9.0 11.0
13.0 3.0 5.0 7.0 9.0 11.0 13.0 forming portion (mm) Diameter of
chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0 11.0 13.0
glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00014 TABLE 14 Example 157 158 159 160 161 162 163 164 165
166 167 168 Glass Ge composition Ga (% by mole) Sb As 40.0 40.0 S
60.0 Se 60.0 Te Bi Sn Glass transition point 185 197 (.degree. C.)
Inner diameter of 15 15 15 15 21 30 15 15 15 15 21 30 stirring
portion (mm) Inner diameter of 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0
7.0 9.0 11.0 13.0 forming portion (mm) Diameter of chalcogenide 3.0
5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0 11.0 13.0 glass material (mm)
Striae .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
TABLE-US-00015 TABLE 15 Example 169 170 171 172 173 174 175 176 177
178 179 180 Glass Ge composition Ga 20.0 8.2 (% by mole) Sb 27.7 As
S 59.0 Se Te 80.0 Bi Sn 5.1 Glass transition point 147 239
(.degree. C.) Inner diameter of 15 15 15 15 21 30 15 15 15 15 21 30
stirring portion (mm) Inner diameter of 3.0 5.0 7.0 9.0 11.0 13.0
3.0 5.0 7.0 9.0 11.0 13.0 forming portion (mm) Diameter of
chalcogenide 3.0 5.0 7.0 9.0 11.0 13.0 3.0 5.0 7.0 9.0 11.0 13.0
glass material (mm) Striae .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle.
TABLE-US-00016 TABLE 16 Comparative Example 1 2 Glass Ge 5.0 4.0
composition Ga (% by mole) Sb 33.0 4.0 As S 61.0 Se 92.0 Te Bi 1.0
Sn Glass transition point (.degree. C.) 230 248 Diameter of glass
base material (mm) -- 15 Diameter of chalcogenide glass material
(mm) 5.0 5.0 Striae X X
[0051] Samples in Examples 1 to 60 and a sample in Comparative
Example 2 were produced in the following manner. Raw materials were
mixed to give each composition shown in the tables, thus obtaining
a raw material batch. Next, a 15-30 mm inner diameter quartz glass
ampoule washed in pure water was evacuated with the application of
heat, the raw material batch was then put into the quartz glass
ampoule, and the quartz glass ampoule was sealed with an oxygen
burner while being evacuated. The sealed quartz glass ampoule was
raised in temperature to 650 to 1000.degree. C. at a rate of 10 to
20.degree. 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 every two hours to stir the melt. Thereafter,
the quartz glass ampoule was taken out of the melting furnace and
rapidly cooled to room temperature, thus obtaining a columnar glass
base material having a diameter shown in the table.
[0052] The obtained glass base material was heated to a temperature
30 to 50.degree. C. higher than the glass transition point in a
nitrogen atmosphere and drawn by a redraw process, thus obtaining a
columnar chalcogenide glass material having a diameter shown in the
table.
[0053] Samples in Examples 61 to 120 were produced in the following
manner. Raw materials were mixed to give each composition shown in
the tables, thus obtaining a raw material batch. Next, a 15-50 mm
inner diameter quartz glass ampoule washed in pure water was
evacuated with the application of heat, the raw material batch was
then put into the quartz glass ampoule, and the quartz glass
ampoule was sealed with an oxygen burner while being evacuated. The
sealed quartz glass ampoule was raised in temperature to 650 to
1000.degree. C. at a rate of 10 to 20.degree. 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 every two
hours to stir the melt. Thereafter, the quartz glass ampoule was
taken out of the melting furnace, a portion thereof was cut in a
nitrogen atmosphere, and the melt was poured into a carbon-made
mold and rapidly cooled to room temperature, thus obtaining a
columnar chalcogenide glass material having a diameter shown in the
table.
[0054] Samples in Examples 121 to 180 were produced in the
following manner. Raw materials were mixed to give each composition
shown in the tables, thus obtaining a raw material batch. Next, a
quartz glass ampoule washed in pure water was evacuated with the
application of heat, the raw material batch was then put into the
quartz glass ampoule, and the quartz glass ampoule was sealed with
an oxygen burner while being evacuated. The sealed quartz glass
ampoule having an inner diameter of a stirring portion and an inner
diameter of a forming portion each shown in the table was raised in
temperature to 650 to 1000.degree. C. at a rate of 10 to 20.degree.
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 every two hours to stir the melt. Thereafter, the quartz glass
ampoule was taken out of the melting furnace and the melt was moved
to the forming portion and rapidly cooled to room temperature, thus
obtaining a columnar chalcogenide glass material having a diameter
shown in the table.
[0055] Comparative Example 1 was produced in the following manner.
Raw materials were mixed to give a composition shown in the table,
thus obtaining a raw material batch. Next, a 5 mm inner diameter
quartz glass ampoule washed in pure water was evacuated with the
application of heat, the raw material batch was then put into the
quartz glass ampoule, and the quartz glass ampoule was sealed with
an oxygen burner while being evacuated. The sealed quartz glass
ampoule was raised in temperature to 800.degree. C. at a rate of
15.degree. C./hour in a melting furnace and then held for ten
hours. During the holding time, the quartz glass ampoule was turned
upside down every two hours to stir the melt. Thereafter, the
quartz glass ampoule was taken out of the melting furnace and
rapidly cooled to room temperature, thus obtaining a chalcogenide
glass material.
[0056] The obtained samples were measured or evaluated in terms of
glass transition point and striae.
[0057] The glass transition point was measured with a TMA
(thermo-mechanical analyzer).
[0058] Striae were evaluated in the following manner. The inside of
each of the obtained samples was observed by a shadow graph method
using infrared light with a wavelength of 1 .mu.m. Samples in which
striae with a length of 500 .mu.m or more were observed are
indicated by a "circle" sign, whereas samples in which no stria
with a length of 500 .mu.m or more was observed are indicated by a
"cross" sign. FIG. 1 shows a photograph of the inside of the sample
in Example 1. FIG. 2 shows a photograph of the inside of the sample
in Comparative Example 1.
[0059] No stria with a length of 500 .mu.m or more was observed in
the samples in Examples 1 to 180 and, therefore, these samples
exhibited excellent homogeneity. In addition, since these samples
were unpolished, they can be considered to have excellent weather
resistance and mechanical strength. On the other hand, striae with
a length of 500 .mu.m or more were observed in the samples in
Comparative Examples 1 and 2 and, therefore, these samples
exhibited poor homogeneity.
INDUSTRIAL APPLICABILITY
[0060] The chalcogenide glass material according to the present
invention is suitable as an optical element, such as a lens for
focusing infrared light on an infrared sensor part of an infrared
camera.
* * * * *