DE3644297A1 - HEATED GLASS PANEL - Google Patents

Description

The invention relates to a heatable glass pane according to the preamble of claim 1.

Such heated glass panes are, for example as windshields in motor vehicles or the like Chen used. Due to the heating, the disc should as quickly as possible of ice, hoarfrost, moisture precipitation or the like are released so that Driver's view is not obstructed. The one with the Be Heating effects of the disc are in the the following description in summary as "defrost" designated.

To explain the prior art, reference should already be made here to FIG. 1 of the drawing, in which a conventional heatable glass pane 10 is shown. The pane 10 has a transparent, electrically conductive film 12 applied to a surface of a glass plate 12 and containing tin oxide as the main component. On the same surface of the glass plate at two opposite edges of the bus bars or electrodes 13 a and b formed. 13

To defrost the disk 10 , a voltage is applied to the busbars 13 a and 13 b , so that an electric current flows in the union union on the entire surface of the conductive film 12 .

The electrical resistance of the film 12 between the busbars 13 a and 13 b is of the order of 2.5 Ω. In order for a current of, for example, 20 amperes to flow through the entire surface of the conductive film 12 , a relatively high voltage of 50 V is therefore necessary. When defrosting the pane, this results in high energy consumption. On the other hand, if the power consumption is reduced, the disk cannot be defrosted quickly enough.

If the conductive film 12 has an uneven thickness, there is also an uneven distribution of the electrical resistance. In this case, if current flows through the entire surface of the film 12 , the resulting current density is distributed unevenly, as indicated by broken lines in FIG. 1. This results in areas with high current density being excessively heated, which leads to an aging or decrease in quality of the conductive film 12 .

The invention is based, a quick Ab thaw the disc with low power consumption possible without the conductive film aging or in its quality is impaired.

The solution to this problem according to the invention is in patent Claim 1 specified.

According to the current path through in the leit capable film trained slots limited so that not the entire surface of the film has electricity flowing through it becomes.

This allows the conductive in predetermined areas Films the desired current can be achieved so that the disc in these areas despite low performance can be defrosted quickly.

Alternatively, a comb-shaped current path can also be used be, so that fluctuations in the current density and thus a  excessive local heating of the pane can be avoided. This will affect the quality of the conductive film prevented.

Further advantageous embodiments of the invention result itself from the subclaims.

Preference is given to a suitable choice of the slot patterns the current density in the different areas the disc controlled so that certain areas of the Disk defrosted with priority.

The width of the slots in the conductive layer is 0.1 mm or less. With this slot width it will Appearance of the conductive film is not affected and ensures a perfect field of vision. Another The advantage of this arrangement is that solar heat radiation is reflected.

Preferred embodiments of the Invention explained with reference to the drawings.

Show it:

Figure 1 shows a conventional conductive glass. and

Fig. 2 to 18B seventeen different embodiments of the invention.

In the case of conductive glass plates or panes 21 to 29 according to the first to ninth exemplary embodiments of the invention, a three-layer conductive film 32 is applied to a surface of a glass plate 31 by spraying (sputtering) or the like. The three-layer structure comprises a MO _x -Ag-MO _x system (MO _x stands for SnO ₂ , ZnO, In ₂ O ₃ , ITO, TiO ₂ or the like). In each of the disks 21 to 29 busbars or electrodes 33 a and 33 b are arranged along two opposite edges on the same surface of the glass plate 31 . The only exception is the eighth exemplary embodiment of the invention shown in FIG. 9, in which the busbars 33 a and 33 b only extend over half the length of the edges of the glass plate 31 .

The transparent conductive film 32 is each provided with slits 34 which are cut mechanically with the aid of a blade (width 20 to 40 μm) or with the aid of a laser cutter or the like (with a width of a few micrometers).

The slots 34 have different patterns, as shown in FIGS. 2 to 10. In any case, the slots 34 have longitudinal sections which extend in the longitudinal direction of the busbars 33 a and 33 b . If a voltage is applied to the busbars 33 a and 33 b in each of the disks 21 to 28 , the current cannot flow through the slots 34 . Since the slots 34 are arranged such that they have sections in the longitudinal direction of the busbars 33 a and 33 b , non-conductive areas are formed through the slots 34 , so that the current flow is also limited between the non-conductive areas of the conductive areas.

The ratio of a conductive area to one is not leading range is the first to ninth Embodiments in the range of 1: 2 to 1: 5 Performance that is required to be in the conductive Areas the same current density as the conventional one  To achieve the target is reduced to 1/2 to 1/5. In de-icing in the non-conductive areas, Drying or the like by conduction from the conductive areas.

If, at a ratio of the conductive areas to the non-conductive areas within the range of 1: 2 to 1: 5, the absolute width of the individual conductive areas is excessively reduced, that is, if the number of the slots 34 is very large, it may through the large number of slots 34 come to impairment of the field of vision. For this reason, the width of the conductive areas in the first to ninth embodiments is about 10 to 50 mm.

If the width of the slits 34 exceeds 100 μm, the slits 34 become visually striking. If the width is between 50 microns and 100 microns, the slot 34 is not noticeable, although it can be seen with the naked eye. However, when the width of the slit is in the range between 20 µm and 50 µm, the slit 34 is hardly visible to the naked eye. With a slot width between 1 μm and 20 μm, the slot 34 cannot be seen at all with the naked eye. However, if the slit width is reduced below 1 µm, the slits 34 cannot be made satisfactorily. In this case, the slot manufacturing process becomes unstable, so that complete, gapless slots are not formed.

The width of the slots 34 in the first to ninth exemplary embodiments of the invention is therefore at most 100 μm and is preferably in the range between a few micrometers and 50 μm.

The transparent conductive film 32 does not have to be formed by several layers, but can also be formed as a single layer from SnO ₂ , In ₂ O ₃ or the like.

In a tenth shown in Fig. 11A and 11b exemplary embodiment of the invention are in the conductive transparent film 32 of a disc 41, two slots 34 mechanically using a blade (width 20 microns to 40 microns) or using a laser (width of a few microns ) cut one. The slots 34 extend vertically from an edge to approximately the center of the transparent film 32 .

On the surface of the disk 41 provided with the film 32 , busbars 33 a , 33 b and 33 c which are interrupted by slots are arranged along one edge and accommodate the slots 34 between them. Another busbar 33 d extends essentially over the entire length of the opposite edge of the disc.

In the disk 41 , a voltage is applied to the busbars 33 a to 33 c such that the bus bars 33 a and 33 b form anodes, while the bus bar 33 c forms a cathode. The busbar 33 d remains dead.

In this state, a current flows from the bus bars 33 a and 33 b to the bus bar 33 c . Since the current, however, the slots 34 can not cross, the current bypasses the slots 34, as shown by dashed line in Fig. 11A.

For this reason, the current density in the vicinity of the free ends of the slots 34 is greater than in the other areas. Even if only a relatively low voltage to the busbars 33 c is applied to 33 a, the surface regions of the disk can be of the slots 34 quickly freed of dew or ice in the vicinity of the free ends.

If the surface areas at the free ends of the slots 34 are completely defrosted or defrosted, the polarity of the voltage applied to the busbar 33 c is reversed, so that there is also a positive voltage and at the same time a negative voltage is applied to the bus bar 33 d as shown in Fig. 11B.

In this state, there is a uniform current flow substantially over the entire surface of the transparent conductive film 32 , as shown by broken lines in Fig. 11B. The entire upper surface of the film 32 is thus slowly defrosted.

A plate 42 shown in FIGS. 12A and 12B according to an eleventh embodiment of the invention differs from the tenth exemplary embodiment described above essentially only in that the two slots 34 extend from opposite sides of the conductive film 32 so that they are with come relatively close to their free ends. At the opposite edges of the disk busbars 33 a and 33 b or 33 c and 33 d are arranged on both sides of the respective slot 34 .

Referring to FIG. 12A, a voltage is so seemed to the bus 33 a to 33 d is applied, that the bus bars 33 form a and 33 c anodes, while through the bus bars 33 b and 33 d cathode are formed. In this case, the surface area between the free ends of the slots 34 is defrosted or de-iced or the like, that is, a high current density results in this area.

Fig busbars are subsequently invention. 12B reversed, so that the bus bar 33 b is a positive polarity and the busbar 33 c receives a negative polarity and substantially the entire upper surface of the film 32 is uniformly defrosted.

A disk 43 shown in FIGS. 13A and 13B according to a twelfth embodiment of the invention is similar to the disk 41 according to the tenth embodiment. However, the slots 34 here extend from two adjacent corners towards the center of the film 32 , and the busbars 33 a to 33 d are arranged on the four sides of the film 32 .

In this embodiment, a voltage is selectively applied to the bus bars 33 a to 33 d such that the bus bar 33 a serve as an anode and the bus bars 33 b and 33 c serve as cathodes and the disk in an area with high current density in the vicinity of the free Ends of the slots 34 are defrosted as shown in Fig. 13a.

Fig busbars are subsequently invention. 13B b 33 and 33 c turned off and simultaneously a negative voltage on the busbar 33 is applied d, so that substantially the entire surface of the master-capable film is uniformly defrosted 32nd

In a washer 51 according to a thirteenth embodiment of the invention, which is shown in FIG. 14, the slots 34 are at regular intervals at right angles to two opposite edges of the conductive film 32nd The slots are cut mechanically into the film using a blade (20 to 40 µm wide) or using a laser device (a few micrometers wide).

The film 32 is divided by the slots 34 into four equally large areas 32 a to 32 d . Busbars 33 a and 33 b , 33 c and 33 d , 33 e and 33 f as well as 33 g and 33 h each run on the opposite edges of the areas 32 a to 32 d .

In the above-described glass sheet 51 only one voltage to the busbars 33 a and 33 b is placed at first, while the busbars 33 to 33 c h abge remain switched on. The current therefore flows only between the busbars 33 a and 33 b without crossing the slot 34 , and is thus limited to the area 32 a of the film.

Even if only a relatively low voltage is applied to the busbars 33 a and 33 b , a sufficient current density is achieved in the area 32 a . Therefore, the disc can be defrosted even at low power consumption at least in the area 32 a . When the area 32 is completely defrosted, a voltage is applied in turn to the bus bars 33 c and 33 d , 33 e and 33 f and 33 g and 33 h , so that the areas 32 b , 32 c and 32 d are independent of one another be defrosted.

The areas 32 a to 32 d can, however, also be defrosted in a different order. If the amount of ice or frost on the disc 51 is only small, and all the areas 32 can be defrosted a to 32 d at the same time.

A disk 52 according to a fourteenth embodiment of the invention shown in FIG. 15 is similar to the disk 51 according to the thirteenth embodiment. Here, the film 32 is only divided into three areas 32 a to 32 c with bus bars 33 a to 33 f , and in each area two additional slots 35 are provided, each having longitudinal sections in the longitudinal direction of the bus bars.

Through the slots 35 non-conductive areas be limited, so that the current can only flow in the intermediate conductive areas.

In the fourteenth embodiment, the same current density as in the thirteenth embodiment Achieve example with lower power consumption. The non-conductive areas of the pane are exposed to heat defrosted from the conductive areas.

In Fig. 16A and 16B, a disc 61 is shown according to a fifteenth embodiment of the invention, in which four slots 34 extend from the four corners of the disc forth until in the vicinity of the center of the conductive film 32. The slots are, for example, cut mechanically or burned in with the aid of a laser.

The surface of the disk 61 provided with the conductive film 32 is provided with four collective notes 33 a to 33 d running along the edges of the disk.

Referring to FIG. 16A, a voltage is selectively applied in such a way to the busbars, that the bus bar 33 a forms an anode, while the bus bar 33 b forms a cathode and the bus bars 33 c and 33 d abge remain switched on. In this state, a current flows bypassing the slots 34 between the bus bars 33 a and 33 b , as indicated by broken lines in Fig. 16A.

The central region of the film 32 lying between the free ends of the slots 34 therefore has the highest current density. Even if the voltage applied to the busbars 33 a and 33 b is relatively low, this central area can be defrosted quickly. After the central portion of the film is defrosted 32 to a certain degree, a voltage is so applied selectively to the busbars, that the busbar 33 c the anode and the busbar 33 d the cathode forms, while the bus bars 33 a and 33 b abge are switched as shown in Fig. 16B.

As further indicated by broken lines in FIG. 16B, the highest current density also results in the central region of the film 32 in this case.

When the central area of the film 32 is completely defrosted, the remaining areas of the disk are not yet completely defrosted, but the defrost front has penetrated to a certain extent in this area, so that a sufficient field of vision for the driver is ensured. When the voltage continued to the busbars 33 a and 33 b and to the busbars 33 c and 33 d is creates is, the defrosting process proceeds, until finally the entire film is defrosted 32nd

A disk 62 according to a sixteenth embodiment of the invention shown in FIGS. 17A and 17B is similar to the disk 61 according to the fifth embodiment, with the exception that only two diagonal slits 34 are formed in the film 32 .

First, FIG 17A, the bus bar is invention. 33a as an anode and the busbar 33 b connected as the cathode, and then the bus bar 33 is shown in FIG. 17B c as the anode and the busbar 33 turns d ge as a cathode.

The transparent film 32 is therefore defrosted within a very short time in its central region and partly also in the other regions.

A disk 63 according to a ge in Fig. 18A and 18B shown seventeenth embodiment of the invention is similar in principle to the disk 61 according to the sixth exemplary embodiment. However, the slots 34 go here right angle from the central portions of the edges of the disc, and the bus bars 33 a to 33 d are L-shaped in the four corners of the film 32nd The free ends of the slots 34 lying opposite each other come relatively close in the central region of the disk.

In the disk 63 18A first, the bus bar 33 a as an anode and the bus bar 33 is in accordance. B connected as the cathode, while the busbars 33 and 33 d c turned off. Fig busbar 33 is then compounded. 18B c d connected as the cathode as an anode and the busbar 33, and the bus bars 33 a and 33 b are turned off.

Here, too, the central area of the film 32 is immediately defrosted, and the remaining areas of the disk are also defrosted to a certain extent within a short time.

While in the above-described embodiments, the transparent conductive film 32 and the bus bars 33 a to 33 h are arranged on a surface of the glass plate 31 , the conductive film and the bus bars can also be arranged inside a laminated glass pane.

Claims (7)

1. Heated glass pane with a transparent, electrically conductive film ( 32 ) and at least two busbars ( 33 a - 33 h ) for power supply to the conductive film ( 32 ), characterized by slots formed in the conductive film ( 32 ) ( 34 ) to limit a current path between the busbars ( 33 a - 33 h ). 2. Glass pane according to claim 1, characterized in that two busbars ( 33 a , 33 b ) extend substantially parallel to one another and that the slots ( 34 ) in the longitudinal direction of the busbars ( 33 a , 33 b ) have extending sections . 3. Glass pane according to claim 1, characterized in that the slots ( 34 ) from the edges to a predetermined area of the conductive film ( 32 ) and that each two busbars ( 33 a , 33 b , 33 c ) are arranged on opposite sides of each slot ( 34 ). 4. Glass pane according to claim 3, characterized by a further busbar ( 33 d) , which is arranged on both sides of the slots ( 34 ) arranged busbars ( 33 a - 33 c ). 5. Glass pane according to claim 1, characterized in that the slots ( 34 ) divide the conductive film ( 32 ) into several areas ( 32 a - 32 d ), and that at least two busbars ( 33 a - 33 h ) in each of the Areas ( 32 a - 32 d ) of the film are arranged. 6. Glass pane according to claim 1, characterized in that the slots ( 34 ) from opposite edges of the conductive film ( 32 ) protrude one another and that the busbars ( 33 a - 33 d ) on all edges of the glass plate ( 31 ) are arranged. 7. Glass pane according to one of claims 1 to 6, characterized in that the width of the slots ( 34 ) is less than or equal to 100 microns.