WO1993004885A1

WO1993004885A1 - Anti-glare device for vehicle windscreens

Info

Publication number: WO1993004885A1
Application number: PCT/DE1992/000657
Authority: WO
Inventors: Frieder Heizmann
Original assignee: Robert Bosch Gmbh
Priority date: 1991-08-29
Filing date: 1992-08-08
Publication date: 1993-03-18
Also published as: DE4128717A1; DE4128717C2; AU2426292A

Abstract

Proposed is an anti-glare device for vehicle windscreens, the device darkening the windscreen in dependence on the angle of incidence (W) of the sunlight falling on the windscreen, thus protecting the driver from being dazzled. The intensity of the sunlight falling directly on the windscreen is determined by a sensor (7). The windscreen is darkened in strips, until the incident sunlight no longer dazzles the driver. Prior art electrochromic glass or liquid-crystal films can be used to modify the transparency. The anti-glare device is also suitable for use in reducing the heating-up of the vehicle when it is parked in direct sunlight. Designing the anti-glare device with a matrix-type layout can be used to give partial transparency.

Description

Anti-glare protection on vehicle windows

State of the art

The invention relates to an anti-glare device on a pane according to the preamble of the main claim. Glare protection devices for motor vehicle windows are already known which are intended to protect the driver of the vehicle from incident light, for example by folding down a sun visor. In the case of the known sun visors, however, the driver is insufficiently protected since, in particular in the case of incident sunlight with a small angle of incidence, there is practically no protective effect. In addition, since the sun visor only covers part of the windshield, the driver is also blinded by light falling from the side. Furthermore, a glass coating with an electrochromic glass is known from the publication "Strom in der Scheibe", magazine High Tech (issue 8/89, pages 10, 11), which can be used for windows of a motor vehicle. The glass coating is converted into a light-impermeable coating by means of an electrical signal which is emitted by a light sensor. However, this is the result Problem that this method cannot be used for the windshield of the motor vehicle, since the driver of the vehicle no longer has a view on the matt windshield and would therefore drive "blindly".

Advantages of the invention

The anti-glare device according to the invention with the characterizing features of the main claim has the advantage that only individual areas of the pane are opaque depending on the angle of incidence of the incident light. The remaining pane remains translucent so that the driver has a clear view of the road to be driven. It is particularly advantageous that the pane is darkened in strips until there is no glare from the incident light. It is also particularly advantageous that the anti-glare device works automatically without the driver or a passenger in the vehicle having to carry out manual operation.

Advantageous further developments and improvements of the anti-glare device specified in the claim are possible through the measures listed in the subclaims. It is particularly advantageous that the switchable areas of the anti-glare device lie one above the other in strips. As a result, the sunlight, which generally falls on the window from above, can be blocked out in such a way that it never dazzles the driver. It has been found to be advantageous that the width of the individual switchable areas increases from top to bottom. Because the lower the sun is, the smaller the aperture area projected onto the driver.

The arrangement of the sensor behind the window in the interior of the vehicle is particularly advantageous since the individual anti-glare areas can be connected in succession until they cover the sensor in a suitable form. The next area of the anti-glare device is switched dark only as long as sunlight falls on the sensor. This results in a simple regulation for the anti-glare device, which is determined by the angle of the incident light, in particular sunlight.

The design of the sensor with at least two photosensitive sensors arranged one above the other advantageously enables a relative measurement between the diffuse ambient light and the direct sunlight. As a result, the anti-glare device works independently of daylight.

Due to the arrangement of the sensor, direct sunlight can either fall on both sensors or only on the lower sensor. The upper sensor then measures the ambient light, while the lower sensor receives the direct sunlight. This state indicates that the desired areas have been switched.

Since sun glare also depends on the seating position and the size of the driver, a changeable arrangement of the position of the sensor is particularly favorable. As a result, an automatic displacement of the sensor can be carried out manually or, if the position of the sensor is combined with the position of the driver's seat.

Particular advantages result from the fact that the switchable areas have an electro-luminescence layer or a liquid crystal layer, since these layers can be switched to opaque or translucent in a particularly simple manner by means of an electrical signal.

Since the arrangement of the anti-glare device is independent of the function of the windows, it can also be used particularly advantageously on side windows, rear windows and sun roofs. A further advantage arises in particular when there is strong sunshine on a parked vehicle. To protect against accidental heating of the vehicle, all the windows can be darkened automatically. This also results in increased protection against an intrusion into the vehicle, since it is no longer possible to look into the vehicle from the outside. This advantage is particularly significant at night when it is not possible to look into a vehicle parked on the street. Car radios, cell phones or other devices often tempt you to break in.

It is also to be regarded as particularly advantageous that the regions are formed with a switchable matrix, so that individual segments or groups can be switched to translucent or opaque. Such a matrix is very easy to manufacture and has the advantage that the area does not become completely opaque, but remains transparent for a certain light level. As a result, the pane is not completely darkened, but instead results in a smooth transition from opaque to translucent if the matrix is arranged and controlled accordingly. The soft transition is perceived as particularly pleasant.

drawing

An embodiment of the invention is shown in the drawing and explained in more detail in the following description. FIG. 1 shows a vehicle window, FIGS. 1 a and 1b show a section through the window, FIGS. 2, 2a, 2b show a vehicle window in plan view and in section with a partial covering of a panel, FIGS. 3, 3a, 3b show the vehicle window with a first one Glare protection, Figures 4, 4a, 4b shows the vehicle window with a first glare protection at different angles of incidence of sunlight, Figure 5, 5a, 5b shows a vehicle window with 2 glare protection 6, 6a, 6b shows the vehicle window with two anti-glare areas at different light incidence angles, FIG. 7, 7a, 7b shows a vehicle window with 3 anti-glare areas, FIG. 8 shows the arrangement of the sensor on a window, FIG. 9 shows a block diagram of the Control circuit, Figure 10 shows a table and Figure 11 shows a matrix of a glare protection area.

The subject of the invention is explained in more detail below with the aid of the figures. In Figures 1, la, lb to 7, 7a, 7b, a windshield 1 is shown both in supervision and in the two sections A-A and B-B. Figures 1, la and lb show a commercially available windshield 1. The section A-A is provided perpendicular to the window 1 in approximately the position of the driver. The section B-B is provided in parallel in the middle of the disk. FIG. 1 a shows part of the hood 2, the windshield 1 and the roof 3 of a vehicle in section A-A. In position 4, the driver's eye level is assumed. Figure lb, with the section B-B differs from the figure la in that a sensor 7 is arranged behind the windshield 1 at about the driver's eye level. The sensor 7 has two photosensitive sensors 5, 6 arranged one above the other and at a predetermined distance. The sensor 7 is slidably arranged on a device (not shown) so that it can be adjusted, for example, according to the size of the driver. The photosensitive sensors 5, 6 have photodiodes or similar light-sensitive components.

In FIGS. 2, 2a and 2b, a rectangular aperture surface 10, which is always opaque, is arranged in the area of the section BB on the upper edge of the windshield 1. In Figure 2a, an edge ray 20a of the sunlight is drawn, which does not cause glare. The edge ray 20a forms an angle of incidence w with the horizontal. A further edge beam 21a with a smaller angle of incidence w almost causes the driver 4 to be dazzled. FIG. 2b shows the two marginal rays 20b, 21b for the section BB. The aperture surface 10 causes the edge beam 20b not to fall on the sensor 7. The edge beam 21b, which is parallel to the edge beam 21a, falls on both sensors 5, 6 of the sensor 7. The two sensors 5, 6 now give a signal to an evaluation circuit shown in FIG. 9, which will be described later. A first aperture region 11 is now switched opaque by the evaluation circuit (FIG. 3).

As can be seen from FIGS. 3a and 3b, the light beam 21a, 21b can neither blind the driver 4 nor fall on the sensor 7 through the aperture region 11. A further edge beam 22a, which penetrates through the pane below the aperture area 11, does not hit the driver 4, but it does hit the sensor 6 of the sensor 7. The sensor 5 is not hit by the edge beam 22b (FIG. 3b) .

In FIGS. 4, 4a, 4b it is assumed that the angle of incidence w of the solar radiation becomes even smaller. In FIG. 4, the diaphragm area 11 is switched to dark again. An edge beam 23a (FIG. 4a) just does not lead to the driver's eye 4. In the case of FIG. 4b, the corresponding beam 23b falls on the sensor 7 with the two transmitters 5, 6. As a result, a further diaphragm area 12 is switched on according to FIG. The aperture area 12 is also strip-shaped and is arranged below the aperture area 11. The aperture areas 11, 12 have corresponding cutouts in the area of the aperture surface 10, which are matched to the arrangement of the sensor 7. This has the effect that the sensor 7 can be arranged close behind the pane, its size being relatively small. In a further embodiment of the invention, however, it is provided to arrange a sensor row vertically to the diaphragm areas 11, 12, 13, which has a plurality of sensors arranged one above the other. FIGS. 5, 5a and 5b show the switched-on diaphragm surface 12 and the new marginal rays 24a and 24b that are created as a result. The new edge beam 24a (FIG. 5a) does not blind the driver 4, the corresponding beam 24b still falls on the transmitter 6, but no longer on the transmitter 5.

FIGS. 6, 6a, 6b and 7, 7a, 7b show the anti-glare device when the position of the sun is even lower, so that a further aperture surface 13 is activated. In FIG. 6a, the edge beam 25a has almost reached the glare limit for the driver 4, the parallel beam 25b (FIG. 6b) falls on both transmitters 5, 6 of the sensor 7. A third aperture region 13 is thereby switched on (FIG. 7). Figure 7a shows both the old edge beam 25a and the new edge beam 26a, which likewise no longer reaches the driver. According to FIG. 7b, the corresponding beam 26b only falls on the transmitter 6, no longer on the transmitter 5. The beam 25b does not penetrate through the pane. The number of aperture areas 11, 12, 13 is arbitrarily specified. Any number or few areas can be switched. It is particularly advantageous that the respective upper diaphragm area is narrower than the subsequent lower diaphragm area, since the respective diaphragm area projected onto the driver's eyes 4 and the sensor 7 is smaller the lower the sun is.

As already mentioned, the activation threshold for the individual aperture area must be set individually for the respective driver. For this purpose, either the two sensors 5, 6 of the sensor 7 are moved parallel to the windshield or vertically or a sensor with a photodiode array is used. Two photodiodes of the photodiode row are then optionally used. It is particularly advantageous if the position or the selection of the photodiodes can be stored in an appropriate device for an individual driver. So that the sensor can also react to obliquely incident light, it must be arranged close enough to the windshield 1 or the aperture surface 10. The position shown in FIGS. 1b to 7b is only schematic in order to better illustrate the effects of the angle of incidence of the sun's angle. In order to achieve a favorable adaptation for the sensor 7, a cutout according to the diaphragm areas 12, 13 or a corresponding tongue according to the diaphragm area 11 can be provided.

The evaluation circuit of FIG. 9 shows the two transmitters 5, 6 of the sensor 7, which are connected to inputs of the amplifiers 60, 61 for signal processing. The outputs are connected to the inputs of the comparators 62, 63. The comparators 62, 63 receive their switching threshold from the limit transmitters 64, 65, which show a potentiometer tap. The outputs of the comparators 62, 63 are connected to a logic logic circuit (e.g. AND gate) 66, 67. The logic circuit 66, 67 is connected to corresponding inputs UP / Hold, DOWN / Hold of a counter without modulo. The counter 68 is connected to a decoder 69, the outputs of which are connected to the control lines of the diaphragm areas 11, 12, 13. The counter 68 also has a hand switch 70. With the help of the han switch 70, the individual aperture areas 11, 12, 13 can optionally be switched on manually, so that the windows of the vehicle can be darkened independently of the measurements of the sensor 7. This is particularly advantageous in parked vehicles, in strong sunshine and heating of the vehicles or as a protective measure against burglary and theft. The counter 68 is clocked by means of a clock signal. The components listed are commercially available and are therefore known to the person skilled in the art.

FIG. 10 shows a table of values which represents the function of the counter. Depending on the 4 switching states of the two encoders 5, 6, the counter output is specified, which is used for dark switching the aperture areas 11, 12, 13 leads. A zero means that the diaphragm area is translucent, while a 1 means translucent. A zero signal is present when an encoder 5, 6 measures ambient light. The switching threshold can be set using limit switches 64, 65. Instead of the fixed limit values, it is of course also possible to provide a further photodiode as a variable limit indicator, which regulates the limit value depending on the ambient light. If, on the other hand, sunlight falls directly on an encoder 5, 6, the limit value has been exceeded and a 1 signal is decoded.

FIG. 8 shows an exemplary embodiment for the arrangement of the sensor 7, in which sunlight incident through the side windows can lead to glare for the driver. The side windows 32, 42 are shown adjacent to the windshield 1. The side windows 32, 42 have corresponding aperture areas 34, 44. The sensor 7 is again arranged in the central region of the windshield 1, but is shielded against light falling directly from the front by two blind screens 30, 40 arranged at an angle of approximately 90 °. A laterally incident light beam 33a, which is not yet dazzling the driver 4, falls as a light beam 33b onto the transmitter 31 of the sensor 7. If the light beam 33b were incident from the front, it would not be visible due to the glare screens 30, 40 the encoder 31 still fall on the encoder 41. In this case, the corresponding light beam 33a would not strike the driver either. The incident light beam 33b on the left one of the two sensors 31, 41 arranged side by side causes the left side window 32 to be darkened by the diaphragm area 34. The right side window 42 remains translucent. Even with this arrangement, which in principle works according to the same functional principle as that previously described for the windshield, a multi-lane darkening of a side window can be provided, especially in connection with the sensors 5, 6. Instead of the two sensors 31, 41 can of course also be used a single encoder, so that the circuit arrangement is further simplified. In a further embodiment of the invention, a matrix arrangement for one or more aperture regions 11, 12, 13 is provided according to FIG. The diaphragm area 11, 12, 13 has horizontally and vertically extending electrodes 50, 51 which can be controlled via contacts 52, 53. The electroluminescent layer or a liquid crystal layer is located in the intermediate layer between the electrodes.

If a voltage is applied to at least one of the electrode pairs 50, 51, the overlapping area of the electrode pairs 50, 51 is darkened. In this way, an aperture area can be electrically darkened in certain points. This results in a particular advantage that not the entire diaphragm area 11, 12, 13 is darkened, but that it can be switched partially translucent. As a result, the contrast between the sun shield and the unprotected pane surface can be adjusted as required. The contacting of the individual electrodes 50, 51 can be carried out very easily using appropriate contact adhesives. The control and selection of the corresponding segments of the matrix can take place via a switch (not shown), with the aid of which the corresponding electrodes 50, 51 can be selected.

Claims

Expectations

1. Anti-glare device on a pane, in particular a motor vehicle pane, with a device which can be reversibly switched from translucent to opaque and with a sensor which switches the device as a function of the incident light, characterized in that the device at least has a switchable glare area (11, 12, 13) which can be switched as a function of the angle of incidence (W) of the light incident on the pane (1).

2. Anti-glare device according to claim 1, characterized in that the switchable diaphragm areas (11, 12, 13) are strip-shaped one above the other and are arranged in the upper region of the pane.

3. Anti-glare device according to one of the preceding claims, characterized in that the strip width of the switchable diaphragm areas (11, 12, 13) increases from top to bottom.

4. Anti-glare device according to one of the preceding claims, characterized in that the sensor (7) behind the window (1) arranged in the interior of the vehicle and depending on the angle of incidence (w) of the incident light from at least one switchable aperture area ( 11, 12, 13) can be covered.

5. Anti-glare device according to one of the preceding claims, characterized in that the sensor (7) has at least two photosensitive sensors (5, 6) which are arranged one above the other at a predetermined distance.

6. Anti-glare device according to one of the preceding claims, characterized in that the arrangement of the sensor (7) is arranged in the vicinity of the switchable areas (11, 12, 13) and that as the angle of incidence (w) of the incident light becomes smaller, starting from the upper diaphragm area (11), the subsequent diaphragm areas (12, 13) can be switched opaque in succession until the directly incident light no longer falls on at least one of the sensors (5, 6) of the sensor (7).

7. Anti-glare device according to one of the preceding claims, characterized in that when the angle of incidence (w) of the incident light increases, starting from the lowest opaque aperture area (11, 12, 13), the aperture areas (11, 12, 13) can be switched translucently one after the other until the directly incident light falls on the transmitter (6) again.

8. Anti-glare device according to one of the preceding claims, characterized in that the position of the sensor (7) is adjustable relative to the switchable diaphragm areas (11, 12, 13).

9 »Anti-glare device according to one of the preceding claims, characterized in that the sensor (7) has a photodiode array.

10. Anti-glare device according to claim 9, characterized in that either the function of, two photodiodes of the photodiode array can be evaluated and that this choice can be stored and called up.

11. Anti-glare device according to one of the preceding claims, characterized in that the switchable areas (11, 12, 13) has an electrochromic layer or a liquid crystal layer which is electrically controllable.

12. Anti-glare device according to one of the preceding claims, characterized in that the anti-glare device is arranged on the front window, the side windows, the rear window and / or the sunroof of a motor vehicle.

13. Anti-glare device according to one of the preceding claims, characterized in that a photosensitive sensor (31) is arranged behind the diaphragm (30) in such a way that the light incident through the side window (32), which almost blinds the driver (4). leads, also meets the encoder (31).

14. Anti-glare device according to claim 13, characterized in that a further photosensitive sensor (41) is provided, which is aimed at the glare of the passenger.

15. Anti-glare device according to claims 13 or 14, characterized in that the two sensors (31, 41) or the two Blen¬ the _(30, 40) can be replaced by only one donor or a diaphragm.

16. Anti-glare device according to one of the preceding claims, characterized in that the anti-glare device is switchable when a vehicle is parked.

17. Anti-glare device according to one of the preceding claims, characterized in that the diaphragm areas (11, 12, 13) are formed with a switchable matrix, the segments of which can be controlled individually or in groups.

18. Anti-glare device according to claim 17, characterized in that the switching-off process from translucent to opaque and / or vice versa takes place successively within a predetermined time span.