Conductive pattern sheet, glazing having the same, vehicle having the glazing, method of manufacturing the sheet and method of manufacturing the glazing

Abstract

The invention concerns a conductive pattern sheet for use in a glazing, comprising a substrate, a conductive pattern arranged on the substrate, wherein the conductive pattern comprises first and second busbars arranged at opposing edges of the conductive pattern for connecting a power supply thereto, a plurality of conductive lines each conductive line arranged between the first and second busbars, wherein at least a portion of the plurality of conductive lines is configured to have a transition region wherein a change from a first resistance per unit length (R1) at a first end of the transition region to a second resistance per unit length (R2) at a second end of the transition region occurs over a predetermined length (L) of the transition region wherein a rate of change of resistance per unit length (R1-R2)/L is from 1 to 16,000 ohms per centimetre squared and the substrate is a polymer sheet.

Claims

1. Conductive pattern sheet for use in a glazing, comprising: a) a substrate; b) a conductive pattern arranged on the substrate; wherein the conductive pattern comprises: c) first and second busbars arranged at opposing edges of the conductive pattern for connecting a power supply to the conductive pattern; d) a plurality of conductive lines each conductive line arranged between the first and second busbars; e) at least a portion of the plurality of conductive lines is configured to have a transition region wherein a change from a first resistance per unit length (R1) at a first end of the transition region to a second resistance per unit length (R2) at a second end of the transition region occurs over a predetermined length (L) of the transition region; f) wherein a rate of change of resistance per unit length (R1-R2)/L is from 1 to 16,000 ohms per centimetre squared and g) the substrate is a polymer sheet.

2. Conductive pattern sheet according to claim 1, wherein the conductive pattern comprises an etched conductive material.

3. Conductive pattern sheet according to claim 1, wherein the conductive line in the transition region comprises variable width or height or cross-sectional area or resistivity or a combination thereof.

4. Conductive pattern sheet according to claim 1, wherein the conductive line in the transition region has linear sides or curved sides or a combination thereof.

5. Conductive pattern sheet according to claim 1, wherein a rate of change of resistance per unit length in the transition region is linear or a parabolic function.

6. Conductive pattern sheet according to claim 5 wherein the rate of change of resistance per unit length is in a range from 3 to 15,000 ohms per centimetre squared.

7. Conductive pattern sheet according to claim 3, wherein a rate of change of the width or the height or the cross-sectional area or the resistivity of the conductive line in the transition region is linear or a parabolic function.

8. Conductive pattern sheet according to claim 7, wherein the rate of change of the width or the height is in a range from 1 to 540,000 μm per centimetre.

9. Conductive pattern sheet according to claim 1, wherein the predetermined length (L) is in a range from 1 to 10,000 μm.

10. Glazing comprising: a first ply of glazing material; a ply of interlayer material arranged on the first ply of glazing material; a second ply of glazing material arranged on the ply of interlayer material; a conductive pattern sheet according to claim 1 arranged between the ply of interlayer material and the second ply of glazing material.

11. Glazing according to claim 10, wherein a second ply of interlayer material is arranged between the conductive pattern sheet and the second ply of glazing material.

12. Vehicle comprising a glazing according to claim 10, wherein the transition region is in a vision zone of the glazing.

13. Method of manufacturing a conductive pattern sheet comprising: a. providing a substrate; b. arranging a conductive pattern on the substrate; c. arranging first and second busbars at opposing edges of the conductive pattern for connecting a power supply to the conductive pattern; d. arranging a plurality of conductive lines each conductive line between the first and second busbars; and e. configuring at least a portion of the plurality of conductive lines to have a transition region wherein a change from a first resistance per unit length (R1) at a first end of the transition region to a second resistance per unit length (R2) at a second end of the transition region occurs over a predetermined length (L) of the transition region; f. wherein a rate of change of resistance per unit length (R1-R2)/L is from 1 to 16,000 ohms per centimetre squared and g. the substrate is a polymer sheet.

14. A method of manufacturing a conductive pattern sheet according to claim 13, further providing the portion of the plurality of conductive lines in the transition region with variable width or height or cross-sectional area or resistivity or a combination thereof.

15. A method of manufacturing a glazing, comprising: a. providing a first ply of glazing material; b. arranging a ply of interlayer material on the first ply of glazing material; c. arranging a second ply of glazing material on the ply of interlayer material; d. arranging a conductive pattern sheet according to claim 1 between the ply of interlayer material and the second ply of glazing material.

16. Conductive pattern sheet according to claim 5, wherein the rate of change of resistance per unit length is in a range from 5 to 12,000 ohms per centimetre squared.

17. Conductive pattern sheet according to claim 5, wherein the rate of change of resistance per unit length is in a range from 8 to 10,000 ohms per centimetre squared.

18. Conductive pattern sheet according to claim 7, wherein the rate of change of the width or the height is in a range from 10 to 65,000 μm per centimetre.

19. Conductive pattern sheet according to claim 1, wherein the predetermined length (L) is in a range from 10 to 5,000 μm.

20. Conductive pattern sheet according to claim 1, wherein the predetermined length (L) is in a range from 50 to 1,000 μm.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of a conductive pattern sheet (1) according to the invention comprising a substrate (2), a conductive pattern (3) arranged on the substrate, comprising at least a conductive line having a transition region (7) wherein a change of resistance per unit length occurs due to width or height or cross-sectional area or resistivity of the conductive line, or a combination thereof.

(2) FIG. 2 is a close-up of FIG. 1 according to the invention, wherein the transition region comprises a linear change of width from W1 to W2. Dotted lines show how the conductive line would have been without the transition region (7).

(3) FIG. 3 is a cross-section on A-A in FIG. 1 according to the invention wherein the transition region (7) comprises a linear change of height from H1 to H2.

(4) FIG. 4 is a cross-section on A-A in FIG. 1 according to the invention wherein the transition region (7) has a change of height according to a parabolic function, i.e. in a shape having a curved side.

(5) FIG. 5 is a graph of resistance per unit length (y axis) versus distance in a length direction (x axis). At a first end of a transition region (7), width is W1 and resistance per unit length is R1. At a second end of the transition region (7) of length L, width is W2 and resistance per unit length is R2. Bold line shows a linear rate of change of resistance per unit length according to the invention. Dotted line indicates abrupt change in the prior art.

(6) FIG. 6 is a graph of resistance per unit length (y axis) versus distance in a length direction (x axis). At a first end of a transition region (7), height is H1 and resistance per unit length is R1. At a second end of the transition region (7) of length L, height is H2 and resistance per unit length is R2. Bold line shows a linear rate of change of resistance per unit length according to the invention. Dotted line indicates abrupt change in the prior art.

(7) FIG. 7 is a graph of resistance per unit length (y axis) versus distance in a length direction (x axis). At a first end of a transition region (7), height is H1 and resistance per unit length is R1. At a second end of the transition region (7) of length L, height is H2 and resistance per unit length is R2. Bold line shows a parabolic function rate of change of resistance per unit length according to the invention. Dotted line is the prior art.

(8) FIG. 8 is a plan view of a conductive pattern sheet (1) according to the invention, having a plurality of conductive lines (5), a portion (6) thereof having a transition region (7) in each conductive line of the portion (6) wherein a change of resistance per unit length occurs due to width or height or cross-sectional area or resistivity of conductive lines, or a combination thereof. The plurality of conductive lines (5) comprises heating zones Z1, Z2.

(9) FIG. 9 is a cross-section on B-B in FIG. 8 according to the invention. The close-up shows a change in cross-sectional area wherein the sides are rectangular.

(10) FIG. 10 is a cross-section on B-B in FIG. 8 according to the invention, wherein the sides of conductive lines are trapezoidal. At first and second ends of the transition region (7), trapezoidal sided conductive lines have average width W1, W2.

(11) FIG. 11 is a cross-section on B-B in FIG. 8 according to the invention, wherein the sides of conducive lines are curved. At first and second ends of the transition region, curved sided conductive lines have average width W1, W2.

(12) FIG. 12 is a plan view of a conductive pattern sheet (1), like FIG. 8, wherein the portion (6) comprises all conductive lines arranged between the busbars. Each conductive line comprises three heating zones (Z1, Z2, Z3). Resistance per unit length of conductive line (R1, R2, R3) changes gradually to the next in a transition region (7).

(13) FIG. 13 is a plan view of a conductive pattern sheet (1) according to the invention wherein a plurality of conductive lines (5) comprises curved lines. Curved lines have a crimp ratio, i.e. line length divided by distance in a length direction between the busbars (4a, 4b).

(14) FIG. 14 and FIG. 15 are a glazing (10) in cross-section having one or two plies of interlayer material respectively.

(15) FIG. 16 is a vehicle (20) having a glazing (10).

(16) FIG. 17 and FIG. 18 are methods of manufacturing a conductive pattern sheet (1) and a glazing (10).

MODES FOR CARRYING OUT THE INVENTION

(17) The following is a description with reference to the drawings of conductive pattern sheet (1) in an embodiment of the present invention.

(18) Conductive Pattern Sheet

(19) A conductive pattern sheet (1) for use in a glazing comprises a substrate (2). The substrate (2) is a polymer sheet, for example polyvinyl butyral (PVB).

(20) A conductive pattern (3) is provided on a substrate (2) by lithographic etching of a layer of a conductive material, having resistivity in a range 1 to 15 μohm.cm, more preferably 1.7 to 5 μohm.cm, most preferably copper, initially covering at least part of a surface of the substrate (2).

(21) The conductive pattern (3) comprises first and second busbars (4a, 4b) arranged at opposing edges of the conductive pattern (3) for connecting a power supply to the conductive pattern (3). Busbars (4a, 4b) may be made by lithographic etching as described above for the conductive pattern (3) and/or by applying to the conductive pattern (3) a preformed metal foil, preferably tinned metal foil for better soldering.

(22) The conductive pattern (3) comprises a plurality of conductive lines (5) arranged between the first and second busbars (4a, 4b). The plurality of conductive lines (5) may be formed at the same time as the busbars (4a, 4b), so they are electrically connected and/or the plurality of conductive lines (5) is connected to the busbars (4a, 4b) by soldering.

(23) At least a portion (6) of the plurality of conductive lines (5) is configured to have a transition region (7) wherein a change in resistance from a first resistance (R1) to a second resistance (R2) occurs over a predetermined length (L) of the transition region selected to control a rate of change of resistance per unit length.

(24) Examples of conductive pattern sheets (1) for a first glazing comprising three heating zones, as shown in FIG. 12, were simulated. Heating zone Z2 is in a vision zone of the glazing where defrost function is desired. Heating zones Z1 and Z3 are respectively above and below the vision zone. In heating zones Z1 and Z3 demist function is desired.

(25) Table 1 shows results of each heating zone simulated as a resistor. Table 2 shows results of each conductive line simulated as a resistor.

(26) TABLE-US-00001 TABLE 1 Each heating zone as a resistor, first glazing Z1 Z2 Z3 Length (m) 0.896 0.327 0.346 0.224 Width (m) 1.251 1.251 1.251 1.251 Area (m2) 1.121 0.409 0.433 0.280 Voltage (V) 13.500 3.551 7.518 2.431 Current (A) 46.039 46.039 46.039 46.039 Resistance (Ohm) 0.293 0.077 0.163 0.053 Power Density (Wm-2) 400 800 400 Power (W) 621.529 163.498 346.103 111.928

(27) TABLE-US-00002 TABLE 2 Each conductive line as a resistor, first glazing Z1 Z2 Z3 Resistivity (ohm .Math. m) 1.80E−08 1.800E−08 1.800E−08 1.800E−08 Crimp (%) 120% 120% 120% 120% Length (m) 1.0757 0.392 0.415 0.268 Width (average) (μm) 9.50 13.171 6.585 13.171 Height (μm) 12 12 12 12 Area (m2) 1.14E−10 1.580E−10 7.902E−11 1.580E−10 Resistance (ohm) 169.84 44.662 94.543 30.575 Number of lines 579 579 579 579 Spacing (mm) 2.160 2.160 2.160 2.160 R per unit length (ohm/cm) 1.139 2.279 1.139

(28) Table 3 shows examples having transition length equal to 1 μm. Table 4 shows examples having transition length greater than 1 μm, namely 10 μm and 1 mm. Each table shows two transitions, i.e. six transition regions are simulated for the first glazing.

(29) TABLE-US-00003 TABLE 3 Examples of transition length 1 μm, first glazing Transition length 1 μm Z1-Z2 Z2-Z3 Change in width (μm) 6.59 6.59 Rate of change width (μm/cm) 65853 65853 Change of R per unit length (ohm/cm) 1.139 1.139 Rate of change R p.u. length (ohm/cm2) 11,393 11,393

(30) TABLE-US-00004 TABLE 4 Examples of transition length greater than 1 μm, first glazing Z1-Z2 Z2-Z3 Transition length 10 μm Rate of change width (μm/cm) 6585 6585 Rate of change R p.u. length (ohm/cm2) 1,139 1,139 Transition length 1 mm Rate of change width (μm/cm) 65.85 65.85 Rate of change R p.u. length (ohm/cm2) 11.39 11.39

(31) Examples of conductive pattern sheets (1) for a second glazing comprising three heating zones, as shown in FIG. 12, were simulated. Heating zone Z2 is in a vision zone of the glazing where defrost function is desired. Heating zones Z1 and Z3 are respectively above and below the vision zone where demist function is desired.

(32) Table 5 shows results of each heating zone simulated as a resistor. Table 6 shows results of each conductive line simulated as a resistor.

(33) TABLE-US-00005 TABLE 5 Each heating zone as a resistor, second glazing Z1 Z2 Z3 Length (m) 1.115 0.200 0.800 0.115 Width (m) 1.250 1.250 1.250 1.250 Area (m2) 1.394 0.250 1.000 0.144 Voltage (V) 13.500 1.476 11.811 0.212 Current (A) 67.731 67.731 67.731 67.731 Resistance (Ohm) 0.199 0.022 0.174 0.003 Power Density (Wm-2) 400 800 100 Power (W) 914.375 100.000 800.000 14.375

(34) TABLE-US-00006 TABLE 6 Each conductive line as a resistor, second glazing Z1 Z2 Z3 Resistivity (ohm .Math. m) 1.80E−08 1.80E−08 1.80E−08 1.80E−08 Crimp (%) 120% 120% 120% 120% Length (m) 1.338 0.240 0.960 0.138 Width (average) (μm) 9.50 15.581 7.791 62.325 Height (μm) 12 12 12 12 Area (m2) 1.14E−10 1.870E−10 9.348E−11 7.479E−10 Resistance (ohm) 211.263 23.10 184.84 3.32 Number of lines 1060 1060 1060 1060 Spacing (mm) 1.179 1.179 1.179 1.179 R per unit length (ohm/cm) 1.579 0.9627 1.9254 0.2407

(35) Table 7 shows examples having transition length equal to 1 μm. Table 8 shows examples having transition length greater than 1 μm, namely 10 μm and 1 mm. Each table shows two transitions, i.e. six transition regions are simulated for the second glazing.

(36) TABLE-US-00007 TABLE 7 Examples of transition length 1 μm, second glazing Transition length 1 μm Z1-Z2 Z2-Z3 Change in width (μm) 7.79 54.53 Rate of change width (μm/cm) 77906 545344 Change of R per unit length (ohm/cm) 0.9627 1.6847 Rate of change R p.u. length (ohm/cm2) 9,627 16,847

(37) TABLE-US-00008 TABLE 8 Examples of transition length greater than 1 μm, second glazing Z1-Z2 Z2-Z3 Transition length 10 μm Rate of change width (μm/cm) 7791 54534 Rate of change R p.u. length (ohm/cm2) 962.7 1,684.7 Transition length 1 mm Rate of change width (μm/cm) 77.91 545.34 Rate of change R p.u. length (ohm/cm2) 9.627 16.847

(38) Comparative example is second glazing transition region Z2-Z3, having a transition length 1 μm and rate of change of resistance per unit length 16,847 ohm/cm.sup.2.

(39) The above-mentioned conductive pattern sheets, except comparative example second glazing transition region Z2-Z3, are suitable for use in a windshield. The comparative example is unacceptable for a windshield due to shimmer. This unacceptable optical effect is believed to be due to a change in the refractive index of the polymer sheet caused by the high rate of change of resistance per unit length.

(40) Glazing

(41) A glazing (10) according to the invention comprises first and second plies of glazing material (11, 12). An example of a suitable glazing is float glass, preferably soda lime silica glass composition having thickness in a range from 0.5 mm to 25 mm. Any functional coating may be used on any surface of the plies of glazing material. For example, the functional coating may comprise a transparent conductive oxide or silver to provide properties of low emissivity and conduction of electricity.

(42) A ply of interlayer material (13) may be a polymer. An example of a suitable polymer is polyvinyl butyral (PVB). Any thickness of the ply of interlayer material may be used. An example of a suitable thickness is in a range 0.38 mm to 0.76 mm. A second ply of interlayer (14) may be used. For example, each ply of interlayer material may have thickness 0.38 mm.

(43) Use of the Invention

(44) A glazing (10) comprising a conductive pattern sheet (1) according to the invention is also suitable in vehicles, buildings, refrigerator doors, white goods and digital signage to reduce optical distortion in heated glazing having more than one heating zone.

KEY TO THE DRAWINGS

(45) 1—Conductive pattern sheet 2—Substrate 3—Conductive pattern 4a, 4b—First and second busbars 5—Plurality of conductive lines 6—Portion of the plurality of conductive lines 7—Transition region H1, H2—Height of line in first, second heating zone L—Length of transition region R1, R2, R3—Resistance per unit length of line in first, second, third heating zone W1, W2, W3—Width of line in first, second, third heating zone Z1, Z2, Z3—First, second, third heating zones 10—Glazing 11—First ply of glazing material 12—Second ply of glazing material 13—Ply of interlayer material 14—Second ply of interlayer material 20—Vehicle