close

Вход

Забыли?

вход по аккаунту

?

Патент USA US3080248

код для вставки
March 5, 1963
w. GEFFCKEN ETAL
3,030,240
OPTICAL GLASS FREE OF THORIUM
2 Sheets-Sheet 1v
Filed July 27, 1959
* ar - 05%205
4/
-
a”yw
vvv
‘.9
T
vvv\/\/\/\/k1o
f\/
a; 5
_
v
10
2O
\eo/w so 90 3205INVENTOR‘.‘
' WATER GEFFQKEN
F MAMTA HULS TICH
W y5
'
*}
42>» 4 ATTOWW
/
,
March 5, 1963
w. GEFFCKEN ETAL
1
3,080,240
OPTICAL GLASS FREE OF THORIUM
Filed July 27, 1959
2 Sheets-Sheet 2
AAYA
PM
AAAVA 6O
5” 2
v'vv v
40
mvyvvvm
90 r6120; 10
20
so
so
so
:0
so
so 5205
,
nvvavroRSI
WALTER GE PH EN§MARQA HULSTICH
3) W, ZMWPW
‘ A TTOR N E Y5
3,080,240=
United States Patent ()?Fice
Patented Mar. 5, 1963
2
1
tent of less than 27% by weight or with an nd-value of
more than 1.805 can no longer be regarded as stable. A
3,080,240
OPTICAL GLASS FREE OF THORIUM
Walter Getfcken and Marga Faulstich, Mainz, Germany,
characteristic of these compositions is a certain content
of alkaline earth oxide or lithium oxide, and generally
'assignors to Jenaer Glaswcrk Schott & Germ, Mainz, 5 of CaO which in all of the examples disclosed is present
Germany, a corporation of Germany
in amounts of at least 20% of the boric acid content in
Filed July 27, 1259, Ser. No. 829,722
accordance with a molar ratio of CaO to B203 of at least ,
Claims priority, application Germany Aug. 26, 1958
0.216. It is a well known fact that the glass range of
5 Claims. (Cl. 106-47)
pure lanthanum borate, which only exists in the imme
The present invention relates to optical glass com 10 diate vicinity of the composition La2O3= 60 and
positions which are free of thorium.
Prior to this invention, there has been a disclosure of
B203=40
is considerably enlarged by such a content in alkaline
glass compositions which substantially consist of La2O3,
earths relative to boric acid.
Ta2O5, ZrOz, and B203, are free of thorium, and are also
According to the present invention it has been un
15
intended to contain bivalent oxides and W03.
expectedly found that a content of bivalent ions or of
‘The limits of these known glass compositions in per
W03 may be completely avoided, that completely stable
centages by weight were disclosed to be as follows:
glass compositions may be produced merely from B203,
Percent
Lazog, and at least 4% by weight of ZrO2, and/or
20 Ta2O5, and that the optical position of these glass com
B203
La2O3 ..-_.
________________________________ ..._
__ 22
25 to 40
"£21205
_
__
ZrOz _________________________________ __
2 to
W03 _
BaO _
ZnO
__-
positions exceeds even the above mentioned types, pro~
vided the individual constituents are provided in percent
ages by weight as follows:
Percent
10 to 21
_
__
_..___
7
___.
0 to 20
0 to 20
___
O to
6
..._.
0 t0
6
_
25 B203 _________________________________ __ 20 to 40
ZrOz
T3205
wherein
..
_
0 to
t0 12
and provided the lanthanum oxide content has an abso
lute lower limit of 44—0.04 (ZrO2) percent by weight
30
and an absolute upper limit of 60% by weight, and
La2O3+Ta2O5+ZrO2+BaO(+ZnO--WO3)=50
by weight.
to
that it also lies between narrower limits dependent upon
the boric acid and zirconium contents which limits are
In an example of an optical position of nd=l.78, the
upper limit of the refraction was given as 11:44.7. How
ever, it may be proved that such a composition in which
determined by the values given in the following Table I:
Table I
210;, percent
B203
by Wt.
40
37
33. 5
30. 5
27. 5
25. 0
22. 5
55. 0-58. 0
51. 5-58. 0
48. 5-53. 0
51. 5-56. 5
48. 0-56. 5
45. 0-56. 5
45. 0-55. 0
43. 5-54. 0
41. 5-55. 3
44. 0-54. 0
42. 5-52. 5
40. 0-52. 5
45. 0-53. 0
44. 0-52. 0
40. 0-51. 0
46. 5-51. 5
45. 5-51. 5
42. 0-49. 0
20. 0
50
50
44-45
In order to attain intermediate values, they should
the LazOa amounts to a maximum of 40% does not re
sult in a usable glass if the BaO and ZnO are omitted or 45 be graphically interpolated in the above table. The
T3305 content will then lie likewise between two limits
if the W03 does not amount to at least 12%. It is there
which are dependent upon the desired refraction of the
fore necessary to add bivalent oxides or larger amounts
glass in accordance with the following Table II:
Table II
of W03.
nd=
ZrOz, percent
by wt.
1.74
1.76
1.78
1.80
1.82
1.84
1.82
1.80
6.0-9.0
13.0-22.0
17.0-27.0
21.0-29.0
2. 0-9. 0
7. 0-14. 0
11. 5-21. 5
15. 5-25. 5
0-4. 0
0-10. 0
4. 5-17. 5
9. 0-21. 5
25.0-30.5
29.0-31.0
______ ._
19. 0-27. 0
23. 5-27. 0 ______ __
14. 0-25. 0
21. 0-20. 0
27.0
In another prior patent relating to the production of 60 According to the formula given above, in which
(ZrO2) is intended to indicate the percentage of ZIOZ
by Weight, the absolute lower limit of the lanthanum
oxide content will at 0% of ZrOz amount to 44%, while
alkaline earth metals, namely, of LaZO3, Ta2O5, ZrO2,
at 5% of ZrOz it decreases to 43%, and at 7% of ZrOs
and W03, and therefore correspond in this respect to
to 42%. The absolute lower limit of the La2O3 con
the above mentioned compositions, but differ therefrom
tent will decrease to 40% not until the ZrO2 content
by the requirement that the total of the percentages by
amounts to 10%. The existence of such a lower limit
weight of La2O3+Ta2O5+BaO+ZnO should be greater
is surprising particularly in view of the fact that it could,
than 70%, which means that the content in B2O3+possi~
on the contrary, be assumed that an increase of- the
bly SiO2+Al2O3 must be smaller than 30% by weight.
Consequently, the refractive indices attained must be high 70 lanthanum oxide content would result in a decrease in
the stability. This is true especially since the prior art
er and extend up to 1.83. A closer examination will show,
as stated in the begining expressly indicated the ‘value
however, that the glass compositions with a B203 con
a highly refractive glass, there have also been glass com
positions proposed which consist of the oxides of the
3,080,2’20
3
4
of the upper‘limit of La2'O3 to amount to 40% by weight
and since‘ it'also‘ restricted the ZrOz content to 7% by
The La2O3 contents of the glass compositions according
to the invention lie between 40 and 60% by weight and"
the Ta2O5 contents amount to 0 to 30% by weight. How~
this prior proposal therefore have an La2O3 content
ever, as indicated in FIGURES 2 to 4, the following re
which lies "below the absolute lower limit. and therefore 5 Strictions apply:
weight. The glass compositions prepared according to
require fortheir stabilization a content in bivalent oxides
For a ZrOz' content of 0%, Table _IV, ‘lined ‘applies;
or W03,wlrich leads to a considerable impairment of the
ForJaZrOé content of 5%',1Table.IV,11ne '2.appl1es; whilev
. w
optical position and,‘ especially if greater amounts of
For a ZrO21contentof‘10%’, Table IV,'hne~-3 apphes:
W043’ are applied, to .a strong yellow discoloration.
7
Intermediate values of ZrOz and B203; are to. be graphi
These. and otherfeatures and. advantages of the present 10 cally interpolated.
‘
invention .ascompared with the state of; the prior art will
Since La2O3=l00-—B2O3—ZrO2—Ta2O5, the La2O3
now be describedin detail with reference to the accomcontents result from the values as indicated and complied
panying drawings,,in which---
in Table-I.
Table IV
:
ZrOz'perceIitL
B2051I
‘
.
by wt.
.
40'
37
33.5
30.5
10.0-15.0
5. 0-13.5
0-' .5
triangular coordinates of glass compositions according
_
In FIGURE 1 of the drawings, the optical position of
14.5-24.5 ' 18.5-28.5
10. 5-21.0
15.0-25.0
4.0—l8.0
10.0-22.5
,_
25.0 ‘
22.5
22. 0-30; 0 “26.10- .0 ‘
18.0-26.0
21.0-27.0
14.0-25.0
18. 5-255
.
,
20.0
30.0’
25.0
25-20
The ‘optical positionof the glass compositions accord‘-‘
FIGURE" 1 shows an nd+v diagram in which the opti- cal- position‘ of‘a few known glass compositions and- a*
few compositions according to the present-invention is
entered; while
FIGURES 2 to 4 show three-component diagrams in'
to theinvention.
27.5
ing vto ‘the invention-'is-very extreme: This is-true-e‘s'pe
cially for the area 12%;: 1.75 to 1.80-where very-high~v-val'
ueseare attained,- as-well as for refractive indices'above'
1.'825,~ as’indicated' inFIGURE l inwhich a‘few'examples '
are marked by circles. In-thelatter-case'itis not only pos-i
30 sible to produce glass compositions withha' refractive in»
dex of up to 1.87 and more, but these compositions‘ also I
the known glass compositions is indicated by means of
small crosses-and that’ of-the glass compositions accord‘
ing to the invention by means'of small circles.
have extremely high v-values relative tosuch a refraction,
as could previously not be attained without any applica
tion of thorium.
35
FIGURES 2w 4 indicate the stable glass range of
The'best optical positions will be attained if the‘amount
the four-component systems LagOs, Ta2O5, ZrO2, and
of Ta2O5 is held in thevicinity of its'lower limit or, which
B203- as variables, while the zirconium content is shown
in each drawing as being constant and, amounting in
means practically the same, if the lanthanum oxide con
tent is made at least as high as the mean value resulting
FIGURE 2 to 0%, in FIGURE 3 to.5%, and in FIG
URE 4 to 10%. It should be noticed that at a ZrO2 con
from Table 1. Furthermore, the ZrOz content should
preferably be made as high as possible; for example, up
tent of 0%, the stable glass range does not reach the right-v
side limit of the coordinate system. Where the Ta2O5 con
to about 10% forrefractive indices above 1.78.
For refractive indices between 1.74 and 1.78, the upper
limit of the zirconium content may be very well expressed
tent amounts to zero. It is therefore impossibleto .pro-.
duce stableglass compositions if the contents‘of both
by the formula
ZrOz and T 21205 amount to zero. On the contrary, as 45
mentioned in the beginning, such stable compositions
The glass range is limited in FIGURES 2 to 4 toward
require atv least a minimum amount of 4% by weight of
the higher lanthanum oxide contents by a shaded marginal '
both ZrO2 and Ta2O5 taken together.
zone in order to indicate that the glass compositions fall
It. may 'be seen from these drawings that,‘ particularly
ing within this zone can be obtained without crystalliza- 1
with‘ a ZrO2 content of 0 to 5%, the range of the other
tion only in small units. If the lanthanum. oxide content
components B203, La2O3, and Ta2O5 forms a very narrow
is reduced by only 1 to 2%‘ and replaced by the same
strip, which'means that, with a given amount of boric
amount of Ta2O5, the stability will increase so quickly
acid, the admissible La2O3 content can be 'varied only
that large glass units or batches will become possible. If,
within very small limits. The above mentioned absolute .
however, the lanthanum oxide content is reduced to a
lower limit of 44-004 (ZrO2) is therefore attainable only
value below the lower limit, a partial phase separation
in the vicinity of 27% of B2O3,,as indicated in FIGURES
will occur.
2 to 4,-and must be strictly de?ned, as will be subse
Provided that pure raw materials are applied, the
quently explained in greated detail. Since at a constant
glass compositions according to the invent-ion will be
Z1102 content and a givenarnount of boric acid, the total
colorless up to the highest‘ refractive indices, have great
of La2O3 and Tao, must likewise be constant, since 60 hardness, and av very‘ good chemical stability, especially
La2O3+Ta2O5=100——B2O3—ZrO2, the mentioned re.
if the Ta2O5 contents are not made too small.
quirement‘of a" small variability"applies similarly also
For producing the new glass compositions, the purest
t0 1121205.
possible raw materials La2O3, T8205, and ZrO2, prefer
As indicated in FIGURES 2 to 4, the boric acid con
ably in the form of oxides, and boric 'acid' in the form of
tents of the glass compositions according to the invention
vboric acid hydrate. are intimately mixed with each other
lie between 20 and 40% by weight. The refraction then
and ‘melted in portions in a platinum‘crucible at tempera
in e?ect depends only upon this B203 content as indicated
tures of 1300 to 1400” C. The highest temperatures
with’ considerable accuracy in the following Table III.
will be required for the composition with the highest
zro,=5\/100-(n,_1.74)
Table III
7 n5-
1.74v
1.76
38. 5-40
35. 5437
1.78
1.80
1.82
29. 5-30. 5
25-27. 5
B203, per-
cent _____ Q.
1.84
1.86
25
22. 5
,
32. 5-33.‘ 5 .
1.88
'
20
3,080,240
5
6
in which, when ZrOz is present in an ‘amount equal to
content in 'ra,o3+zpo2. The re?ning temperatures
should preferably be about 20° higher than the insertion
zero weight percent, the range of percentages by weight
of the ingredients in the glass is as follows:
temperatures. The molten mixture is thereafter stirred
until it has attained the viscosity necessary for casting,
lngredients-
that is, at a temperature between l000° and 1100° C.
Percent by weight
B203
__
_ 20-37
Finally, the molten mixture is cast in the usual manner
L212O3 ______________________________ __ 44-58
into preheated steel molds and then slowly cooled.
Ta2O5
5-3 1
The following Table V shows a few examples of the
when
ZrOz
is
present
in
an
amount
equal
to
5%
by
weight
glass compositions according to the invention.
the range of percentage by weight of the ingredients in the
10
Table V
‘glass is as follows:
N0.
B2 03
LazOa
T3205
ZI‘O:
'nd
|Ingredients—
v
Percent by weight
B203 _______________________________ __ 20-37
37
37
33
30
25
55
58
53
53
50
3
5
14
17
25
.
.
.
.
.
22
4O
5O
55
37
36
53
58
36
59 ...... _-
35
35
33
30
30
28
23
20
25
35
55
57
5G
45
53
52
50
50
50
50
35
34
33
30
30
25
25
25
23
21
25
28
...... -_
La2O3
51. 2
52. 1
48. 2
46. 7
43. 4
15
41. 7
52. 8
1. 754
1. 757
50. 5
51. 5
5
1. 762
50. 5
5
5
5
5
5
5
5
5
8
10
1. 766
1. 766
1. 777
1. 798
1. 798
1. 807
1. 850
1. 867
1. 840
1. 774
49. 8
50. 3
49. 3
44. 3
46. 7
45. 3
42. 2
41. 0
42. 9
48. 3
55 ______ ..56 ...... -.
10
10
1. 773
1. 781
49. 7
49. 4
52
5O
55
45
50
51
48
43
45
10
10
1n
10
1O
10
1.0
10
12
1. 787
1. 804
1. 803
1. 836
1. 837
1. 841
1. S53
1. 873
1. 843
48. 1
46. l
47. 2
42. 8
43. 6
43. 8
42. 4
40. O
42. 5
5
10
5
20
15
14
19
26
18
gredients in the glass is vas follows:
20
Ingredients-
Percent by weight
B203
La2O3
_
Ta2O5 ______________________________ __
(Zr02 representing a constant having a value of one of
cent:
ZIOz=0
the appended claims.
Having thus fully disclosed our invention, what we
B203
LazOa
T2205
31
37
33
so
25
22
55
5s
5s
as
50
50
s
a
14
17
25
2s
Zr0g=5
claim is:
1. A thorium oxide free optical glass consisting es
Percent 45
sentially of, by weight,
ZrOz
T3205
30
53
_. ____ __
5
2. A thorium oxide-free optical glass consisting es
sentially of, by weight,
B203
__
ZrOg
50
Percent
33
T8205
1.13203
M1203
___ 10
Percent by weight 60
20-40
__________________ _._- ___________ __ 40-60
2:02
53
5s
36
59
35
as
33
30
a0
2s
2a
20
as
57
56
4s
53
52
50
50
.... -
5
1
.... -
5
a
e
20
12
15
22
25
as
50
as
34
55
56
____ -_
.... __
as
30
30
25
25
25
2a
21
52
50
5s
45
50
51
48
43
a
10
5
2o
15
14.
19
26
0-12
T3205 ____
5
ZIOz=12
65
said glass including at lease 4% by weight of one of ZrOz,
Ta2O5 and mixtures thereof.
4. A thorium oxide free optical glass consisting of
B203, LazOg, Ta205, and ZrO2, the range of percentage
by weight of the ingredients in the glass being as follows: 70
IngredientsB203 ___
55
ZIOQ=10
3. A thorium oxide free optical glass consisting of the
following ingredients in the indicated percentages by
weight:
40
e7
36
5 55
_
Ingredients—
B203
0-27
0, 5, 10, and 12) de?ned by straight lines joining the
following composition points expressed in weight per
30
35
__
20-40
__.._ 40-57
5. A thorium oxide free optical glass according to claim
25 3 encompassing within the area of the ternary composi
tion diagram of the elements B203, La2O3 and Ta2O5
Although our invention has been illustrated and de
scribed with reference to the preferred embodiments
thereof, we wish to have it understood that it is in no
way limited to the details of such embodiments, but is
capable of numerous modi?cations within the scope of 40
B203
La2O3 ____
0-27
by weight the range of percentage by weight of the in
.
.
1. 747
5
5
5
3
6
20
12
15
22
25
17
5
____ 43-58
and when Z102 is present in an amount equal to 10%
5
5
1
_
Ta2O5 ______________________________ __
Percent by weight
____
20-40
Zr02
1.3.203 _______________________________
.---_
__
0-10
T3205 _______________________________ __
0"3 1
75
2a
45
18
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,861,000
2,866,712
2,899,322
3,006,776
Ge?cken et al _________ __ Nov. 18, 1958
Weissenberg et al _______ __ Dec. 30, 1958
Bromer et al __________ _... Aug. 11, 1959
Ge?cken _____________ __ Oct. 31, 1961
UNITED STATES PATENT OFFICE
CERTIFICATE, OF CORRECTION
Patent N0o 3vO80q24O
I
March 5,, 1963
Walter Geffcken et al0
It is hereby certified that error appears in the above numbered pat
ent requiring correction and that the said Letters Patent should read as
corrected below.
Column 27 line 29, for "(ZrOg)" read -- (ZrO2)2 ——;; line
729 for “begining?Q read —- beg-inning -—; column 3“ line 59?
for "'greated"I read —~ greater -=-; column 4, line 12a for
"complied" read --'- compiled ---3 column 5, line 65n for
‘"lease"
read
-=-
least —-—-,
Signed and sealed this 1st day of October 1963‘,
(SEAL)
Attest:
ERNEST w. SWIDER
Attesting Officer
4
DAVID L-YLADD
_
Commissioner of Patents
Документ
Категория
Без категории
Просмотров
0
Размер файла
511 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа