Ruggedized switchable glazing, and/or method of making the same

Abstract

Certain example embodiments of this invention relate to ruggedized switchable glazings, and/or methods of making the same. The PDLC stack of certain example embodiments includes an outer substrate, a low-E UV blocking coating deposited on an inner surface of the outer substrate, a first PVB or EVA laminate, a first PET layer, a first TCO layer, the PDLC layer, a second TCO layer, a second PET layer, a second PVB or EVA laminate, and an inner substrate. The substrates may be glass substrates. The low-E UV blocking coating may include at least two layers of or including silver and/or may include one or more IR layers. Thus, certain example embodiments may advantageously reduce one or more problems associated with residual haze, color change, flicker, structural changes in the polymer and/or the LC, degradations in state-switching response times, delamination, etc. The PDLC stack of certain example embodiments may be used in connection with any form of coated article, such as, for example, windows, windshields, IG units, etc.

Claims

1. A coated article including a low-E coating supported by a glass substrate, the low-E coating comprising: first and second IR reflecting layers comprising silver and/or gold; a UV blocking layer that blocks significant amounts of UV light having a wavelength of from 380-400 nm so that no more than about 20% of light having a wavelength of from 380-400 nm passes through the low-E coating; wherein the UV blocking layer is positioned so as to not directly contact the first and second IR reflecting layers; and wherein the UV blocking layer is located between and directly contacting first and second layers comprising tin oxide.

2. The coated article of claim 1, further comprising first and second polymer inclusive laminating layers separated by at least a liquid crystal inclusive layer, wherein the low-E coating is provided between the glass substrate and the first and second polymer inclusive laminating layers.

3. The coated article of claim 2, wherein the liquid crystal inclusive layer is stable up to at least about 110 C.

4. The coated article of claim 2, wherein the liquid crystal inclusive layer is stable up to at least about 120 C.

5. The coated article of claim 1, wherein an off-axis haze of the coated article is less than or equal to about 4 at an incidence of approximately 45.

6. The coated article of claim 1, wherein an off-axis haze of the coated article is less than or equal to about 3 at an incidence of approximately 45.

7. The coated article of claim 1, wherein an off-axis haze of the coated article is less than or equal to about 2 at an incidence of approximately 45.

8. The coated article of claim 1, wherein the UV blocking layer comprises zinc oxide.

9. The coated article of claim 1, wherein the UV blocking layer comprises zinc oxide doped with bismuth.

10. The coated article of claim 1, wherein the UV blocking layer comprises bismuth.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features and advantages may be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which:

(2) FIG. 1a is a conventional PDLC glass window in an off state;

(3) FIG. 1b is a conventional PDLC glass window in an on state;

(4) FIG. 2 is a cross-sectional view of a window in accordance with an example embodiment of this invention;

(5) FIG. 3 is a cross-sectional view of an insulating glass (IG) window unit in accordance with an example embodiment of this invention;

(6) FIG. 4 is a graph of experimental data that illustrates the general ineffectiveness of the PVB in containing the UVA incidence (the vertical axis of the graph represents percent transmission, and the horizontal, axis of the graph represents wavelength in nm);

(7) FIG. 5 is a graph of experimental data that illustrates the advantages gained by ruggedizing the PDLC in accordance with an example embodiment (the vertical axis of the graph represents percent transmission, and the horizontal axis of the graph represents wavelength in nm);

(8) FIG. 6 is an example multi-layer low-E UV blocking coating that may be used in connection with certain example embodiments; and

(9) FIG. 7 is another example multi-layer low-E UV blocking coating that may be used in connection with certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

(10) Certain example embodiments provide PDLC windows using an effective blocking layer as well as a double or triple silver layer so as to reduce the incidence of the PDLC warming and therefore help to solve of one or more of the above-described and/or other problems associated with conventional PDLC techniques. The UV blocking layer preferably has at least about 99.5% UV cut-off below 410 nm. In certain example embodiments, the UV blocking layer is temperable. Certain example embodiments therefore may advantageously reduce one or more problems associated with residual haze, color change, flicker, structural changes in the polymer and/or the LC, degradations in state-switching response times, delamination, etc.

(11) FIG. 2 is a cross-sectional view of a window in accordance with an example embodiment. In the window of FIG. 2, two substrates (e.g., glass substrates) are provided, including an outer substrate 202 and an inner substrate 204. A low-E UV blocker 206 is deposited on the inner surface of the outer substrate 202. The low-E coating 206 may be, for example, of the type disclosed in U.S. Pat. No. 7,056,588 or U.S. Pat. No. 6,887,575, or application Ser. No. 11/281,598, the entire contents of each of which is hereby incorporated herein by reference. The low-E coating 206 also may include one or more infrared reflecting (IR) layers in certain example embodiments. Furthermore, the low-E coating may include one or more UV blocking layers, or a separate UV blocking coating may be applied, e.g., proximate to one or more of the low-E coatings described above. Further details of an example low-E UV blocking layer are provided below, e.g., with reference to FIGS. 6 and 7.

(12) A first laminate layer 208 comprising a polymer-based material (e.g., PVB and/or EVA) is applied over the low-E UV blocking coating 206 proximate to surface 2 of the window. A second laminate layer 208 also comprising a polymer-based material (e.g., PVB and/or EVA) is applied on the inner surface of the inner substrate 204 (on surface 3 of the window). The first and second laminate layers 208 may be applied to the respective surfaces, via rolling and cured via an autoclaving process, for example.

(13) The liquid crystal inclusive (e.g., PDLC) layer 214 is disposed approximately in the center of the cross-sectional stack shown in FIG. 2. Sandwiching the PDLC 214 are first and second TCO layers 212. The first and second TCO layers 212 may be of, or include, for example, ZnAlO.sub.x, SnO.sub.x:F, SnSbO.sub.x, or the like, in certain example embodiments. The TCO layers may be sputtered onto one or both surfaces of the PDLC 214 and/or the respective surfaces of the first and second polymer-based (e.g., PET) layers 210 that are more proximate to the PDLC 214.

(14) First and second polymer-based layers 210 are provided between the first and second laminate layers 208 and the first and second TCO layers 212, respectively. The first and second polymer-based layers 210, the first and second laminate layers 208, and the low-E UV blocking coating 206 extend at least the width of the PDLC 214 so as to protect it.

(15) One or more bus bars are provided, e.g., to provide voltage to the PDLC 214, either directly or indirectly. In certain example embodiments, two bus bars are respectively connected to the first and second TCO layers 212. A groove or channel is cut in each of the first and second laminate layers 208. In certain example embodiments, when viewed in cross section, the grooves may be substantially U-shaped, with the first groove being upwardly oriented and the second groove being downwardly oriented. Also, in certain example embodiments, the grooves may be disposed at opposing corners of the PDLC stack, e.g., such that the first groove is disposed in the upper left corner of the PDLC stack while the second groove is disposed in the lower right corner of the PDLC stack. Of course, it will be appreciated that the foregoing description is provided by way of example and without limitation and that other arrangements may be used in connection with certain other example embodiments (e.g., when only one bus bar is used, when differently shaped channels are formed, etc.).

(16) Each groove may be formed by laser cutting (e.g., using a CO.sub.2 laser), using a half-cutter, or via any suitable means. The groove is filled with a silver paste, and a flat wire ribbon is bonded thereto. Voltage may be provided through this ribbon so as to cause the PDLC 214 to become activated. The voltage may be connected to a switch (not shown) in certain example embodiments.

(17) FIG. 3 is a cross-sectional view of an insulating glass (IG) window unit in accordance with an example embodiment. FIG. 3 is similar to FIG. 2. For example, the same liquid crystal inclusive (e.g., PDLC) stack of a low-E UV blocking coating 206, a first laminate layer 208, a first polymer-based (e.g., PET) layer 210, a first TCO layer 212, the PDLC 214, a second TCO layer 212, a second polymer-based (e.g., PET) layer 210, and a second laminate layer 208 are provided between second and third substrates (e.g., glass substrates) 202, 204. However, as shown in FIG. 3, a first substrate 302 (e.g., glass substrate) is located proximate to the second substrate 202. The first and second substrates 302, 202 are separated, e.g., by an air gap 304, so as to provide insulating features for the IG unit. The three substrates are substantially parallel to one another.

(18) Thus, the example embodiment shown in and described with reference to FIG. 3 may be thought of as being a conventional IG unit, with the low-E UV blocking coating conventionally found on surface 2 of the window being moved to surface 4 of the window, along with the other elements of the PDLC stack of certain example embodiments.

(19) Also, in connection with certain of the example IG units described herein, a low-E (and/or UV or UVA blocking) layer may be provided on surface 2 of the window (e.g., on the inner surface of the first substrate 302 proximate to the air gap 304) in certain example embodiments. This low-E layer may augment or replace the low-E UV blocking coating 206 located on the inner surface of the second substrate 202, depending on the illustrative implementation chosen.

(20) In certain example embodiments, the periphery of the stack is left open (e.g., not sealed). However, in certain other example embodiments, a seal (e.g., a polymer-based seal) may be provided around the periphery of the window and/or at least the PDLC stack, so as to reduce the amount of water, debris, etc., from entering into the unit.

(21) FIG. 4 is a graph of experimental data that illustrates the general ineffectiveness of the PVB in containing the UVA incidence. The graph shows the transmission of visible light (Tvis) and the reflectance of visible light (Rvis) of a full laminate with clear PVB in the 300 to 500 nm range. Light having a wavelength above about 4.00 nm (e.g., from about 400 nm to about 700 nm) typically is visible. The sample tested was a piece of clear glass, 1.7 mm thick. In FIG. 4, line 402 corresponds to transmission of light, line 404 corresponds to inward reflection, and line 406 corresponds to outward reflection. As can be seen from FIG. 4, about 99% of UV transmission is blocked up to about 380 nm. However, the UV transmission increases markedly thereafter. The reflection in and out is very low throughout all wavelengths. Thus, as will be appreciated from FIG. 4, the PVB alone does little to block UVA incidence and provides low inward and outward reflection (also resulting in, for example, poor insulating features and leading to one or more of the above-described and/or other drawbacks).

(22) By way of contrast, FIG. 5 is a graph of experimental data that illustrates the advantages gained by ruggedizing the PDLC in accordance with an example embodiment. More particularly, Tvis and Rvis are shown for a half-laminate with a double silver low-E and UV blocking film being disposed on surface 2 of the window, in accordance with an example embodiment. The sample tested was clear glass, coated with SunGuard SN 68 and ClimaGuard SPF (both commercially available from Guardian) and incorporating a 0.030 PVB laminate layer, bringing the total thickness to about 3 mm. In FIG. 5, line 502 corresponds to transmission of light, line 504 corresponds to inward reflection, and line 506 corresponds to outward reflection. Unlike the arrangement that produced the results of FIG. 4 in which the PVB alone does not block light having a wavelength from about 380-400 nm, the arrangement of FIG. 5 and of certain example embodiments includes a low-E and UVA blocking layer that does block light having a wavelength from about 380-400 nm. There is an average of about 65% transmission between about 400 nm and 650 nm. Tvis falls rapidly until about 900 nm, and is greatly reduced above about 1300 nm. Reflection in and out range from about 5% to about 10% in the wavelength range of about 300-600 nm, and then climb markedly starting at about 600 nm. Thus, as will be appreciated from FIG. 5, substantially more UVA incidence is blocked, and Rvis is higher at substantially all wavelengths. There is also good transmission of visible light.

(23) The following table provides additional experimental data, showing the changes in haze, E*-value, and percent of visible transmission in various test samples from 0-hour UV exposure over a number of different UV exposure times produced according to certain example embodiments. For example, a*=a*.sub.1a*.sub.0, with a*.sub.0 being the a* value after 0 hours of UV exposure, b*=b*.sub.1b*.sub.0, with b*.sub.0 being the b* value after 0 hours of UV exposure, L*=L*.sub.1L*.sub.0, with L*.sub.0 being the L* value after 0 hours of UV exposure, etc. As can be appreciated from the table below, the samples created in accordance with certain example embodiments held-up very well in terms of changes in haze, E*-value, and percent of visible transmission, even after over 3,000 hours of UV exposure. Unless otherwise noted, the procedure for gathering the data in the table involved measuring each sample twice in the off state. Then, each sample was measured twice in the on state after waiting approximately 4 minutes. The data provided below represents the average of the two measurements. It was discovered that on state values are cyclical and do not always stabilize.

(24) Sample 4 provides a comparative example, in that one-half of the sample did not have a UV blocking coating, whereas the other half of the sample did have a UV blocking coating. L*, a*, and b* represent transmissive measurements.

(25) TABLE-US-00001 UV Sample # Sample 1 Sample 2 Sample 3 Sample 4 Sample 4 Time Type UV Blocker UV Blocker UV Blocker no UV Blocker UV Blocker (hrs) State Off On Off On Off On Off On Off On 0 Haze 101 5.95 102 6.68 102 6.94 102 7.62 102 7.62 % Tvis (Y 2/C) 1.66 72.09 1.29 70.65 1.23 67.52 1.31 68.21 1.31 68.21 L* (2/C) 13.57 88.01 11.19 87.31 10.81 85.77 11.36 86.11 11.36 86.11 a* (2/C) 4.61 0.75 2.36 0.76 2.46 1.57 1.98 1.15 1.98 1.15 b* (2/C) 9.17 5.38 6.44 5.61 6.52 8.09 6.13 4.98 6.13 4.98 336 Haze 101 5.92 102 6.80 102 7.07 102 7.22 102 7.71 % Tvis (Y 2/C) 1.64 70.99 1.32 68.59 1.19 68.53 1.56 67.24 1.47 68.75 L* (2/C) 13.48 87.48 11.40 86.29 10.47 86.27 12.97 85.62 12.38 86.38 a* (2/C) 4.70 0.51 2.57 0.99 1.79 0.91 3.41 0.85 2.63 0.82 b* (2/C) 9.09 5.26 6.57 6.90 5.44 6.63 8.25 5.45 6.97 4.43 Haze 0.0 0.0 0.5 0.1 0.5 0.1 0.0 0.4 0.0 0.1 % Tvis (Y 2/C) 0.0 1.1 0.0 2.1 0.0 1.0 0.3 1.0 0.2 0.5 E* 0.2 0.6 0.3 1.7 1.3 1.7 3.0 0.7 1.5 0.7 672 Haze 101 6.15 102 6.77 102 7.02 102 7.43 102 7.74 % Tvis (Y 2/C) 1.74 70.50 1.32 69.44 1.24 68.87 1.45 67.11 1.41 68.72 L* (2/C) 14.06 87.24 11.41 86.72 10.86 86.43 12.30 85.56 12.03 86.36 a* (2/C) 5.07 0.66 2.63 0.78 2.04 0.90 3.14 0.72 2.56 0.78 b* (2/C) 9.81 5.66 6.57 5.62 5.88 6.47 7.70 5.60 6.87 4.53 Haze 0.0 0.2 0.5 0.1 0.5 0.1 0.5 0.2 0.0 0.1 % Tvis (Y 2/C) 0.1 1.6 0.0 1.2 0.0 1.4 0.1 1.1 0.1 0.5 E* 0.9 0.8 0.4 0.6 0.3 1.9 2.2 0.9 1.2 0.6 1008 Haze 101 6.04 102 6.76 102 7.03 102 7.39 102 7.76 % Tvis (Y 2/C) 1.74 69.88 1.30 68.74 1.24 67.31 1.42 66.66 1.39 68.36 L* (2/C) 14.07 86.93 11.28 86.38 10.84 85.66 12.10 85.33 11.87 86.19 a* (2/C) 5.09 0.78 2.54 0.98 2.05 1.33 3.01 0.74 2.54 0.76 b* (2/C) 9.79 6.19 6.47 6.46 5.84 7.95 7.64 5.81 6.73 4.65 Haze 0.0 0.1 0.5 0.1 0.5 0.1 0.5 0.2 0.5 0.1 % Tvis (Y 2/C) 0.1 2.2 0.0 1.9 0.0 0.2 0.1 1.6 0.1 0.2 E* 0.9 1.4 0.2 1.3 0.3 0.3 2.0 1.2 1.0 0.5 1344 Haze 101 6.42 102 6.86 102 7.29 102 7.415 102 7.81 % Tvis (Y 2/C) 1.67 70.47 1.33 69.06 1.21 69.62 1.48 66.28 1.42 68.16 L* (2/C) 13.67 87.23 11.45 86.54 10.60 86.81 12.53 85.14 12.08 86.09 a* (2/C) 4.66 0.59 2.79 0.83 1.87 0.55 3.42 0.73 2.74 0.79 b* (2/C) 9.25 5.62 6.65 6.26 5.53 5.29 8.29 6.06 7.01 4.82 1680 Haze 0.0 0.5 0.5 0.2 0.5 0.4 0.5 0.2 0.5 0.2 % Tvis (Y 2/C) 0.0 1.6 0.0 1.6 0.0 2.1 0.2 1.9 0.1 0.1 E* 0.1 0.8 0.5 1.0 0.6 3.2 2.8 1.5 1.4 0.4 Haze 100.5 5.93 101.5 6.65 100.85 6.985 102 7.62 102 7.47 % Tvis (Y 2/C) Data 71.03 1.30 69.95 Data 69.85 1.42 66.00 1.42 67.33 L* (2/C) missing 87.50 11.26 86.98 missing 86.92 12.11 84.99 12.08 85.67 a* (2/C) 0.55 2.55 0.57 0.59 3.07 0.75 2.75 0.88 b* (2/C) 5.45 6.45 5.58 5.37 7.89 6.30 7.08 5.05 Haze 0.5 0.0 0.5 0.0 1.2 0.1 0.5 0.0 0.5 0.2 % Tvis (Y 2/C) 1.1 0.0 0.7 2.3 0.1 2.2 0.1 0.9 E* 0.6 0.2 0.4 3.1 2.2 1.8 1.4 0.5 2016 Haze 102 6.02 102 6.63 102 6.97 102 7.53 102 7.4 % Tvis (Y 2/C) 1.73 70.53 1.30 69.77 1.235 69.93 1.47 65.47 1.56 65.49 L* (2/C) 14.01 87.26 11.28 86.89 10.81 86.97 12.37 84.73 12.97 84.74 a* (2/C) 5.10 0.66 2.60 0.59 2.125 0.51 3.14 0.72 3.39 1.46 b* (2/C) 9.85 5.59 6.56 5.62 5.885 5.39 8.25 6.53 8.13 7.36 Haze 0.5 0.1 0.0 0.0 0.0 0.0 0.5 0.1 0.5 0.2 % Tvis (Y 2/C) 0.1 1.6 0.0 0.9 0.0 2.4 0.2 2.7 0.3 2.7 E* 0.9 0.8 0.3 0.5 0.3 3.1 2.6 2.1 2.9 2.8 2352 Haze 101 5.88 102 6.66 102 6.93 102 7.43 102 7.395 % Tvis (Y 2/C) 1.71 71.09 1.32 69.70 1.23 69.88 1.48 65.42 1.48 65.31 L* (2/C) 13.88 87.53 11.39 86.85 10.80 86.94 12.45 84.70 12.51 84.64 a* (2/C) 5.04 0.55 2.66 0.61 2.12 0.54 3.37 1.37 3.17 0.81 b* (2/C) 9.76 5.59 6.67 5.67 5.90 5.44 8.55 7.24 7.84 6.69 Haze 0.0 0.1 0.0 0.0 0.0 0.0 0.5 0.2 0.5 0.2 % Tvis (Y 2/C) 0.1 1.0 0.0 1.0 0.0 2.4 0.2 2.8 0.2 2.9 E* 0.8 0.6 0.4 0.5 0.3 3.1 3.0 2.7 2.4 2.3 2688 Haze 101 6.08 102 6.66 102 7.09 % Tvis (Y 2/C) 1.75 71.00 1.32 69.75 1.24 69.64 L* (2/C) 14.13 87.49 11.42 86.88 10.83 86.82 a* (2/C) 5.23 0.56 2.69 0.59 2.15 0.56 b* (2/C) 10.02 5.65 6.76 5.75 6.02 5.53 Haze 0.0 0.1 0.0 0.0 0.0 0.2 101.5 7.6 101.5 7.6 % Tvis (Y 2/C) 0.1 1.1 0.0 0.9 0.0 2.1 1.3 68.2 1.3 68.2 E* 1.2 0.6 0.5 0.5 0.2 2.9 13.1 86.3 13.1 86.3 3024 Haze 101 5.94 102 6.56 102 6.76 % Tvis (Y 2/C) 1.815 68.29 1.35 69.78 1.27 69.84 L* (2/C) 14.47 86.15 11.60 86.89 11.05 86.92 a* (2/C) 5.44 1.13 2.86 0.58 2.27 0.55 b* (2/C) 10.48 7.17 6.99 5.77 6.27 5.53 Haze 1.0 0.0 0.0 0.1 0.0 0.2 101.5 7.6 101.5 7.6 % Tvis (Y 2/C) 0.2 3.8 0.1 0.9 0.0 2.3 1.3 68.2 1.3 68.2 E* 1.8 2.6 0.8 0.5 0.4 3.0 13.1 86.3 13.1 86.3

(26) It is noted that after turning the samples to the on state, it takes about 8 minutes for the transmission measurements to re-stabilize in the off state. This was not initially noticed on samples 1, 2, and 3. Off state measurements were taken once samples stabilized. Only one set of initial data for sample 4 was gathered; therefore, it was considered baseline data for both the panel and the UV blocked side.

(27) It will be appreciated that it is desirable to reduce the absolute values of the changes in haze, percent visible transmission, and E* values over time, for both on and off states. Thus, it is preferable to reduce the absolute value of the change in haze to below about 10, more preferably below about 5, even more preferably below about 3, even more preferably below about 2, and most preferably below about 1. Similarly, it is preferable to reduce the absolute value of the change in Tvis (when measure with the Y 2/C method) to below about 5, even more preferably below about 3, even more preferably below about 2, and most preferably below about 1. Again, it is preferable to reduce the change in E* to below about 5, even more preferably below about 3, even more preferably below about 2, and most preferably below about 1. It will be appreciated that the exposure to UV over time may affect one or both of the on and off state measurements. Thus, it may not always be possible to achieve corresponding reductions to the changes in haze, Tvis, and E*, for both the on and off states, although it is still desirable to achieve reductions to the changes in haze, Tvis, and E*, for one of the on and off states even when it is not possible to achieve corresponding results for the other state. Additionally, the off-axis haze advantageously may be reduced to less than or equal to about 10, more preferably less than or equal to about 4, more preferably less than or equal to about 3, and still more preferably less than or equal to about 2 at about 45 incidence. In turn, the reduction in off-axis haze enables the techniques of certain example embodiments to be applied to, for example, automotive backlites, panoramic automotive windshields, etc. In certain example embodiments, haze may be influenced by varying the amount of LC material in the LC-inclusive layer. Generally, including less LC material provides less off-axis haze.

(28) As noted above, there sometimes is a problem related to delamination of curved laminates with sharp edges proximate to high-stress hot-spots. To make curved laminates, certain example embodiments take into account the stiffness of the PET material being used. For example, in certain example embodiments, to attenuate the z-component of the compressive stress below 100 MPa, the PET/LC/PET layers combined may be provided at a thickness that does not exceed about 300 microns. In addition, or in the alternative, stress points may be reduced by the use of laser cutting of the raw LC material in certain example embodiments. By way of example and without limitation, the LC may be laser cut, e.g., so as to include grooves or channels. Such grooves or channels may be located on opposing sides of the stack. In addition to reducing the delamination, these and/or similar grooves also help reduce the formation of wrinkles.

(29) Further details of an example multi-layer low-E UV blocking coating that may be used in connection with certain example embodiments is now provided. Certain example low-E UV blocking coatings may include a layer stack that may permit the coated article to achieve one or more of high selectivity (T.sub.vis/SF), a fairly low solar factor (SF), substantially neutral color at normal and/or off-axis viewing angles, and/or low emissivity. One, two, three, or all of these features may be achieved in different embodiments of this invention. When high selectivity (T.sub.vis/SF) is achieved, there is provided a high ratio of visible transmission (T.sub.vis) to solar factor (SF), which will be appreciated by those skilled in the art as being an indication of a combination of good visible transmission and good solar protection of a building and/or vehicle interior for example.

(30) In certain example embodiments of this invention, a coated article such as an IG window unit (e.g., with two spaced apart glass substrates) realizes a high selectivity (T.sub.vis/SF) of at least 1.75, more preferably of at least 1.80, even more preferably of at least 1.85, and sometimes at least 1.90. In certain example embodiments of this invention, coated articles realize a high selectivity value, in combination with a SF of no greater than 35.0, and more preferably a SF of no greater than 34.0, even more preferably a SF of no greater than 33.0, and most preferably a SF of no greater than 32.5 (SF, or g-value, is calculated in accordance with DIN 67507, the disclosure of which is hereby incorporated herein by reference). This permits coated articles, for example, to realize good selectivity while at the same time blocking significant undesirable radiation from reaching a building interior or the like.

(31) In certain example embodiments of this invention, a coated article is provided which has both high selectivity and desirable coloration at both normal and off-axis viewing angles such as 45 degrees from normal. Moreover, in certain example embodiments, the coloration of the coated article does not shift by more than a predetermined amount between a normal viewing angle and an off-axis viewing angle of 45 degrees for example.

(32) In certain example embodiments of this invention, coated articles realize a visible transmission of from about 50 to 70%, more preferably from about 55 to 65%, and most preferably from about 58 to 64% in a monolithic and/or IG unit context.

(33) Sheet resistance (R.sub.s) is indicative of emissivity or emittance. Low sheet resistance is achieved in certain example embodiments of this invention. In certain example embodiments of this invention, a coated articles realizes a sheet resistance (R.sub.s) of no greater than about 3.0 ohms/square, more preferably no greater than about 2.0 ohms/square, and most preferably no greater than about 1.9 ohms/square before any optional heat treatment such as tempering. Such low sheet resistance values are indicative of low emissivity.

(34) In certain example embodiments of this invention, the low-E coating of a coated article includes only two IR reflecting layers (e.g., only two silver or silver-based layers). While other numbers of IR reflecting layers may sometimes be provided, the use of two is preferable in certain instances in that low-emittance can be achieved and more such layers are not required thereby making coatings easier and cost effective to manufacture and less susceptible to yield problems.

(35) In certain example embodiments of this invention, an IR reflecting layer is located between respective lower and upper contact layers, each of which contacts the IR reflecting layer. The contact layers may be made of material(s) such as an oxide of nickel-chrome (NiCrO.sub.x) in certain example embodiments of this invention. In certain embodiments, the lower contact layer is of the sub-oxide type, whereas the upper contact layer is more oxided than is the lower contact layer. Surprisingly and unexpectedly, it has been found that by using a sub-oxide contact layer under and contacting the IR reflecting layer and a more oxided contact layer over the IR reflecting layer, significantly higher selectivity values and lower SF values may be achieved in combination with desirable coloration at normal and/or off-axis viewing angles. These represent significant example advantages in the art.

(36) FIGS. 6 and 7 are example multi-layer low-E UV blocking coatings that may be used in connection with certain example embodiments. The coated article includes substrate 202 (e.g., clear, green, bronze, or blue-green glass substrate from about 1.0 to 10.0 mm thick, more preferably from about 1.0 mm to 7.0 mm thick), and coating (or layer system) 600 provided on the substrate 202 either directly or indirectly. The coating (or layer system) 600 includes: dielectric titanium oxide layer 601 which may be TiO.sub.x (e.g., where x is from 1.5 to 2.0), first lower contact layer 603 (which contacts IR reflecting layer 605), first conductive and preferably metallic infrared (IR) reflecting layer 605, first upper contact layer 607 (which contacts layer 605), dielectric layer 609 (which may be deposited in one or multiple steps in different embodiments of this invention), dielectric layer 615 may be of or include zinc oxide, second conductive and preferably metallic IR reflecting layer 619, second upper contact layer 621 (which contacts layer 619), dielectric layer 623, and finally protective dielectric layer 625. The contact layers 603, 607, and 621 each contact at least one IR reflecting layer (e.g., layer based on Ag, Au, or the like). The aforesaid layers 601-625 make up low-E coating 600 which is provided on glass or plastic substrate 202.

(37) To improve the low-E coating 600 of FIG. 6 and/or the low-E coating 700 of FIG. 7 to provide enhanced UV blocking features (e.g., blockage of light having a wavelength in the range of about 380-400 nm), additional layers may be added to the stack. For example, in FIG. 6, dielectric layer 609 may be split and an additional UV blocking layer 611 may be added (e.g., between successive layers of the dielectric layer 609). That is, at least some of dielectric layer 609 may be deposited, the UV blocking layer 611 may be deposited, and then the rest of the dielectric layer 609 may be deposited. The UV blocking layer may be of or include zinc oxide doped with bismuth (e.g., ZnBiO or other suitable stoichiometry) or simply bismuth oxide (BiO) in certain example embodiments. In certain other example embodiments, the UV blocking layer 611 may include silver oxide (e.g., AgO.sub.x or other suitable stoichiometry), as described, for example, in U.S. Pat. No. 6,596,399, the entire contents of which is hereby incorporated herein by reference. Similarly, in FIG. 7, the dielectric layer 623 may be split and the UV blocking layer 611 may be inserted therein. In still other example embodiments, a UV blocking layer 611 surrounded by dielectric layers (e.g., of tin oxide) may be located anywhere in the low-E stack.

(38) The improved low-E UV blocking stacks 600 and 700 thus are capable of blocking both UV and IR.

(39) Further details of low-E coatings and stacks may be found, for example, in U.S. Pat. No. 7,198,851 or U.S. Pat. No. 7,189,458 or U.S. Publication No. 2005/0164015, the entire contents of each of which is hereby incorporated herein by reference. For example, dielectric layer 601 may be of or include titanium oxide in certain example embodiments of this invention. This layer is provided for anti-reflective purposes, and preferably has an index of refraction (n) of from about 2.0 to 2.6, more preferably from about 2.2 to 2.5. Layer 601 may be provided in direct contact with the glass substrate 202 in certain example embodiments of this invention, or alternatively other layer(s) may be provided between the substrate 202 and layer 601 in certain instances.

(40) Infrared (IR) reflecting layers 605 and 619 are preferably substantially or entirely metallic and/or conductive, and may comprise or consist essentially of silver (Ag), gold, or any other suitable IR reflecting material. IR reflecting layers 605 and 619 help allow the coating to have low-E and/or good solar control characteristics. The IR reflecting layers 605 and/or 619 may, however, be slightly oxidized in certain embodiments of this invention.

(41) Contact layers 607 and 621 may be of or include nickel (Ni) oxide, chromium/chrome (Cr) oxide, or a nickel alloy oxide such as nickel chrome oxide (NiCrO.sub.x), or other suitable materials), in certain example embodiments of this invention. The use of, for example, NiCrO.sub.x in these layers (607 and/or 621) allows durability to be improved. These contact layers may or may not be continuous in different embodiments of this invention across the entire IR reflecting layer.

(42) In certain example embodiments of this invention, the upper contact layers 607 and/or 621 that are located above the respective IR reflecting layers 605 and 619 are deposited in a manner so as to be oxided to a first extent. In certain example embodiments, the upper contact layers 607 and/or 621 may be substantially fully oxided.

(43) Surprisingly, it has been found that by using an optional sub-oxide contact layer under and contacting the IR reflecting layer 619 and a more oxided contact layer 621 over the IR reflecting layer 619, significantly higher selectivity values and lower SF values can be achieved in combination with desirable coloration at normal and/or off-axis viewing angles. In particular, it has been found that unexpected advantages can be achieved when the optional contact layer under the IR reflecting layer 619 is deposited in a manner so as to be oxided to a lesser extent than upper contact layer 621 on the other side of the IR reflecting layer 619. In certain example embodiments, the optional contact layer an the contact layer 621 may be composed of oxides of the same metal(s), yet be oxided to different extents where the optional lower contact layer is oxided to a lesser extent than is the upper contact layer 621. For example, in certain example embodiments of this invention, the optional lower NiCrO.sub.x contact layer is a sub-oxide (i.e., only partially oxided) whereas upper NiCrO.sub.x contact layer 621 is substantially fully oxided as deposited by sputtering or the like.

(44) In certain example embodiments of this invention, as deposited anchor in the final product which is not thermally tempered in certain embodiments, the optional sub-oxide contact layer may have no more than about 80% of the oxygen content of the upper contact layer 621, more preferably no more than about 70% of the oxygen content of the upper contact layer 621, and most preferably no more than about 60% of the oxygen content of the upper contact layer 621. In each of these cases, as well as others, it will be appreciated that the lower contact layer 617 under the IR reflecting layer 619 is oxided to a lesser extent than is the upper contact layer 621 located over the IR reflecting layer 619 in at least certain portions of the respective contact layers.

(45) In order to deposit the optional sub-oxide contact layer in a manner so as to be less oxided than upper contact layer 621, even when they are oxides of the same metal(s) such as Ni and/or Cr, less oxygen gas flow per kW of sputtering power may be used in sputtering the optional layer compared to layer 621. For example, given similar or the same type of sputtering target(s) (e.g., using NiCr based targets for each layer), an oxygen gas flow of about 5 ml/kW may be used when sputtering the optional sub-oxide lower contact layer, whereas an oxygen gas flow of about 10 ml/kW may be used when sputtering substantially fully oxided upper contact layer 621 (the remainder of the gas flows may be made up of Ar or the like). In this particular example, the oxygen gas flow per kW of sputtering power for the optional sub-oxide layer is about 50% of that for the more oxided upper contact layer 621. In certain example embodiments of this invention, the oxygen gas flow per kW of sputtering power for the optional sub-oxide layer is no more than about 80% of that used for the upper more oxided contact layer 621, more preferably no more than about 70% of that used for the upper more oxided contact layer 621, and even more preferably no more than about 60% of that used for the upper more oxided contact layer 621.

(46) In certain example embodiments of this invention, the upper contact layers 607 and 621 provided over the respective IR reflecting layers may be deposited in similar or the same manners.

(47) Lower contact layer 603 and/or dielectric layer 615 in certain embodiments of this invention are of or include zinc oxide (e.g., ZnO). The zinc oxide of layer(s) 603, 615 may contain other materials as well such as Al (e.g., to form ZnAlO.sub.x). For example, in certain example embodiments of this invention, one or more of zinc oxide layers 603, 615 may be doped with from about 1 to 10% Al, more preferably from about 1 to 5% Al, and most preferably about 2 to 4% Al. The use of zinc oxide 603 under the silver 605 allows for an excellent quality of silver to be achieved.

(48) Dielectric layer 609 may be of or include tin oxide in certain example embodiments of this invention. However, as with other layers herein, other materials may be used in different instances. Dielectric layer 623 may be of or include tin oxide in certain example embodiments of this invention. However, layer 623 is optional and need not be provided in certain example embodiments of this invention. Dielectric layer 625, which may be an overcoat including one or more layers in certain example instances, may be of or include silicon nitride (e.g., Si.sub.3N.sub.4 or any other suitable material in certain example embodiments of this invention. Optionally, other layers may be provided above layer 625. For example, an overcoat layer of or including zirconium oxide (not shown) may be formed directly on top of the silicon nitride layer 625 in certain example embodiments of this invention. Silicon nitride layer 625 may be doped with Al or the like in certain example embodiments of this invention.

(49) Other layer(s) below or above the illustrated coating may also be provided. Thus, while the layer system or coating is on or supported by substrate 202 (directly or indirectly), other layer(s) may be provided therebetween. Thus, for example, the coating of FIG. 6 may be considered on and supported by the substrate 202 even-if other layer(s) are provided between layer 601 and substrate 202. Moreover, certain layers of the illustrated coating may be removed in certain embodiments, while others may be added between the various layers or the various layer(s) may be split with other layer(s) added between the split sections in other embodiments of this invention without departing from the overall spirit of certain embodiments of this invention. Thus, the use of the word on herein is not limited to being in direct contact with.

(50) Certain example embodiments incorporate the illustrate layers described herein so that no more than about 20% of light having a wavelength of about 380-400 nm reaches the PDLC layer. Preferably, less than about 15% of light having a wavelength of about 380-400 nm reaches the PDLC layer. Still more preferably less than about 10%, and most preferably less than about 5%, of light having a wavelength of about 380-400 nm reaches the PDLC layer. Certain example embodiments incorporate the illustrate layers described herein so that the visible transmission of light is at least about 55%, more preferably at least about 60%, still more preferably at least about 65%, and most preferably at least about 70%.

(51) PVB laminates tend to be more resistant to impact. However, in certain example instances, PVB laminates sometimes allow the LC layer to move inwards, degrading the performance and/or appearance of the overall structure. Thus, in certain example embodiments, a polymer (e.g., of an acrylic or an amide) may be provided at the periphery (e.g., proximate, although not necessarily limited, to the edges) of the PDLC film. This polymer may act as barrier, reducing migration of the PVB plasticizer, and reducing the chances of the LC being pushed inwards. Thus, certain example embodiments may include a polymer barrier proximate to the periphery of the PDLC film so as to reduce migration of the PVB and/or movement of the LC layer. It will be appreciated that although the movement of the LC inwards is a problem associated with PVB, a polymer barrier may be used in connection with other laminates. Additionally, encapsulating the PVB and/or EVA proximate to the periphery (e.g., also proximate to where electrical contacts are made), advantageously reduces the assembled unit's susceptibility to humidity encroachment over time. In addition, the combination of the LC-inclusive layer, the PVB and/or EVA, and/or other materials in the assembled unit increases sound attenuation. For example, certain example embodiments, it is possible to achieve sound attenuation up to about 45 dB in the 10-12 kHz band.

(52) The LC-inclusive layer may be made by, for example, emulsion techniques and by solvent-induced phase separation. For example, thin LC-films may be cast from solution onto suitable transparent substrates such as PET, made conductive by TCO deposition. In certain example implementations, heat stability may be provided by using a LC mixture formulation that is stable up to/at least about 100 C., more preferably up to at least about 110 C., and still more preferably up to at least about 120 C. (e.g., in connection with automotive applications). In other words, the LCs in the polymer, the polymer itself, and the mixture thereof, may be stable up to at least about 100 C., more preferably up to at least about 110 C., and still more preferably up to at least about 120 C. One type of LC mixture suitable for use in certain example implementations is commercially available from iGlass, which makes a mixture suitable for high-temperature applications. The iGlass LC mixture involves LCs that have a generally crystalline, basically oblique, structure. Such LCs preferably rotate from about 30-60, and more preferably to about 40, at the application of voltage. High temperature LCs commercially available from Merck (for example, those available with the trade name Licrilite) also may be used in connection with certain example embodiments. It will be appreciated that iGlass and Merck are only two examples of providers of LCs and/or mixtures that may be used in connection with certain example embodiments. Indeed, any suitable nematic LC (e.g., nematic LCs having a higher glass transition temperature) may be used in connection with a suitable polymer (e.g., a formulated polymer) capable of withstanding such temperatures may be used in connection with certain example embodiments. It has been determined that only a few volts per micrometer of film thickness are need to induce optical switching.

(53) Although certain example embodiments have been described in relation to various applications, the present invention is not limited thereto. The techniques of certain example embodiments may be applied to any glass and/or window-like application, such as, for example, vehicle windshields, sunroofs, interior and/or exterior windows, IG units, etc.

(54) Also, the features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.

(55) While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.