Stock material or miscellaneous articles – Composite – Of quartz or glass
Reexamination Certificate
2002-03-14
2004-06-15
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Composite
Of quartz or glass
C428S034000, C428S428000, C428S448000, C428S450000, C428S666000, C428S673000, C428S680000, C428S698000, C428S704000, C427S165000
Reexamination Certificate
active
06749941
ABSTRACT:
Certain embodiments of this invention relate to an insulating glass (IG) window unit including a heat treatable coating having a silicon (Si) rich silicon nitride inclusive layer in order to achieve desired optical characteristics in the window unit. Other embodiments of this invention relate to a heat treatable coated article including a Si-rich silicon nitride inclusive layer in order to achieve desired color.
BACKGROUND AND SUMMARY OF THE INVENTION
Coated articles and IG window units are known in the art. For example, see U.S. Pat. Nos. 5,514,476, 5,800,933 and 6,014,872.
Commonly owned U.S. patent application Ser. No. 09/978,184, filed Oct. 17, 2001 (hereby incorporated herein by reference) discloses a coated article as follows, from the glass substrate outwardly (the top tin oxide layer may be omitted in certain instances) with example thicknesses listed in units of angstroms (Å):
TABLE 1
Example Coating of 09/978,184
Layer
Preferred Range (Å)
More Preferred (Å)
Example (Å)
Glass Substrate
TiO
2
0-700
Å
100-400
Å
200 Å
ZnO
x
25-200
Å
40-150
Å
90 Å
Ag
50-250
Å
80-200
Å
130 Å
NiCrO
x
5-100
Å
15-60
Å
30 Å
SnO
2
0-1,000
Å
500-900
Å
680 Å
ZnO
x
25-200
Å
40-150
Å
90 Å
Ag
50-250
Å
80-220
Å
168 Å
NiCrO
x
5-100
Å
15-60
Å
30 Å
SnO
2
0-500
Å
70-200
Å
125 Å
Si
3
N
4
0-500
Å
120-320
Å
220 Å
When the aforesaid coated article is coupled with another glass substrate in order to make an IG window unit, the resulting IG window unit (not heat treated (HT)) generally has the following optical characteristics (Ill. C, 2 degree observer):
TABLE 2
Optical Characteristics of IG Window Units with Above Coating
(non-HT)
Characteristic
General
More Preferred
T
vis
(or TY) (transmissive):
>=69%
>= 70%
a*
t
:
−6.0 to +1.0
−5.0 to −2.0
b*
t
:
−1.0 to 4.0
0.5 to 3.5
R
g
Y (glass side):
5 to 15%
8 to 12%
a*
g
:
−4.0 to +2.0
−3.0 to −1.0
b*
g
:
−4.0 to +2.0
−3.0 to +1.5
L*
g
:
34 to 42
36 to 40
R
f
Y (film side):
5 to 18%
9 to 15%
a*
f
:
−5.0 to +4.0
−3.0 to +2.0
b*
f
:
−8.0 to +8.0
−5.0 to +6.0
L*
f
:
33 to 48
35 to 45
In Table 2 above, T
vis
stands for visible light transmission, and a*
t
and b*
t
stand for transmissive (t) a* and b* color values, respectively. Glass side (g) and film side (f) values are presented in a similar manner. It is noted that the color values herein (e.g., a*, b*, L*) are calculated in accordance with the CIE LAB 1976 L*, a*, b* coordinate technique.
The IG units of Tables 1-2 (and thus Ser. No. 09/978,184) are not heat treated (HT). However, in commercial applications, at least some IG units often are required to be heat treated (e.g., tempered) for safety purposes. In office buildings for example, it is often desirable that some windows be heat treated while others need not be. Thus, a need for matchability (before heat treatment vs. after heat treatment) arises. In other words, it is desirable that window units which are heat treated (HT) substantially or approximately match their non-heat treated counterparts (e.g., with regard to color, visible transmission, reflectance, and/or the like), at least with respect to transmissive and glass side reflective optical characteristics, for architectural and/or aesthetic purposes.
Unfortunately, coatings of Ser. No. 09/978,184 cannot withstand HT without significant color and/or durability change. Thus, coatings of Ser. No. 09/978,184 cannot be HT and then used commercially to achieve matchability with their non-HT counterparts.
It will be apparent from the above that there exists a need in the art for coatings that, upon HT, approximately match non-HT coatings of Ser. No. 09/978,184 in the context of IG window units with regard to visible transmission, visible reflectance, transmissive color, and/or glass side reflective color.
While coatings having multiple infrared (IR) reflecting Ag layers are desirable in certain instances, they tend to have very low sheet resistance (R
s
) values thereby making them difficult to easily HT (without resulting in damage or becoming prohibitively costly) using inexpensive HT processing/machinery. This is because the dual Ag layers tend to reflect much of the energy in the furnace intended for tempering the underlying glass substrate. Single silver coatings, with higher sheet resistances, are easier to HT in this regard. Thus, in certain example non-limiting instances it would be desirable for coatings herein to achieve the aforesaid matchability and/or be of the single Ag layer type (or have higher R
s
) so that they can be more easily heat treated using conventional low-tech radiant tempering furnaces.
U.S. Pat. Nos. 5,514,476 and 5,800,933 discloses coated articles including: glass substrate/Si
3
N
4
/NiCr/Ag/NiCr/Si
3
N
4
. Unfortunately, upon HT and use in an IG unit, the resulting IG units do not approximately match the general aforesaid optical characteristics of IG units set forth in Table 2.
WO 02/04375 discloses a dual-silver low-E coating have good color characteristics after HT and lamination. Unfortunately, the coatings of WO 02/04375 require multiple silver (Ag) layers and have very low sheet resistance (R
s
) (e.g., about 4-5 ohms/square) before HT. This makes the coatings of WO 02/04375 difficult to HT using conventional low-tech radiant tempering furnaces since the dual Ag layers reflect much of the energy intended for tempering the underlying glass substrate. It is noted that WO 02/04375 is a counterpart to U.S. Ser. No. 09/794,224, filed Feb. 28, 2001.
An object of certain example embodiments of this invention is to provide a coating that, upon HT and in the context of IG window units, approximately matches an IG unit including a non-HT coating of Ser. No. 09/978,184 (see general desired optical characteristics in Table 2 above) with respect to visible transmission (T
vis
), visible glass side reflectance (R
g
Y), transmissive color (a* and/or b*), and/or glass side reflective color (a* and/or b*).
Another object of certain example embodiments of this invention is to provide a single silver (Ag) coating (i.e., including only one Ag layer) that, upon HT and in the context of IG window units, approximately matches an IG unit including a non-HT coating of Ser. No. 09/978,184 with respect to visible transmission (T
vis
), visible glass side reflectance (R
g
Y), transmissive color (a* and/or b*), and/or glass side reflective color (a* and/or b*).
In certain example embodiments of this invention, it would be desirable for the coating, prior to HT, to have a sheet resistance (R
s
) prior to HT of at least 8 ohms/square, more preferably of at least 10 ohms/square, and sometimes from about 11 to 20 ohms/square, so that the coating can be easily HT while on a supporting glass substrate in conventional low-tech radiant tempering furnaces. In certain example embodiments, the coating has only one Ag layer.
Another object of certain example embodiments of this invention is to provide a heat treatable coating that achieves certain desired color characteristics (whether corresponding to non-HT coatings of Ser. No. 09/978,184 or not) through the use of a layer comprising Si-rich (non-stoichiometric) silicon nitride.
Another object of certain example embodiments of this invention is to provide a heat treatable coating that includes a non-stoichiometric silicon nitride layer, wherein the amount of Si in the layer is adjusted (i.e., increased relative to stoichiometric Si
3
N
4
) so as to increase the layer's index of refraction “n” and/or extinction coefficient “k”, in order to achieve desired op
Guardian Industries Corp.
Morris Terrel
Nixon & Vanderhye P.C.
Piziali Andrew T
LandOfFree
Insulating glass (IG) window unit including heat treatable... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Insulating glass (IG) window unit including heat treatable..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Insulating glass (IG) window unit including heat treatable... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3364698