DE3940146A1 - Changing light attenuation passing through glass pane - using LCD cells affected by light impingement angle caused by switchable voltage fields - Google Patents

Abstract

The passing light is attenuated on impinging at different angles. LCD cells, associated with glass pane, are affected by electric voltage field in accordance with the requirements. The voltage fields are switchable, taking into account the respectivee light impinging angle. They are aligned in correspondance to the voltage field. The voltage fields are pref. arranged on either side of the glass pane and are mutually switched from side to side in parallel, or in a phase shift corresp. to the light impingement angle. The light impingement angle may be measured and the phase shift electronically matched. The light intensity, or the point of gravity, may be detected and the attenuation of the glass pane matched in sectors by LCD cell alignment. USE/ADVANTAGE - Protection against light from headlamps of oncoming vehicles. Reliable attenuation even under unfavourable angle, or a changeable one.

Description

The invention relates to a method for change the damping of the glass panes or similar surfaces Light at different angles of incidence at which the Glass crystal assigned liquid crystal cells ent speaking the requirements about electrical voltage fields to be influenced. The invention also relates to a Device for performing the process with the glass disk associated electrical lines, an energy source and assigned to the glass pane, via the generated Alignable liquid crystal cells (LCD cells).

Methods are known with which the light through casualness of discs and. Areas permanently changed becomes. Here in particular is metal vapor deposition, mirroring development and the colored formation of such objects call. It is also known, the translucency to change by self-tinting by exposure to UV light and finally slices of liquid crystals to inte grieren, which by electrical voltage fields to a Darken the window (DE-OS 38 22 796.7, DE-OS 31 42 717, DE-OS 32 05 056, DE-OS 31 28 964, DE-OS 36 43 690, DE-OS 32 23 407 and DE-OS 25 53 976). The procedures working with areas of tension are common sam that it is a controllable darkening of the window enable the respective angle of incidence of light is not taken into account. So far, these discs show so far mainly a reduction in light transmission for approximately perpendicularly incident light. Although there is also a damping effect for obliquely incident light, however, this effect is limited to relatively little Deviations from right-angled light.

So it can happen, for example, that a perpendicular standing window pane against horizontal incidence of light  is darkened and therefore opaque, but that Sunlight from the high sun is almost unhindered can occur because it is at an acute angle on and through the Disc falls. This effect can sometimes be desirable, sometimes unimportant wishes to be. Such an effect is undesirable in Attempt the intense radiation of a high standing To prevent sun. This effect would be desirable for one heavily sloping rear window of an automobile that is there Absorb sunlight that is almost at right angles well could still give the driver an unobstructed view would allow outside. But changes with that The position of the sun is also the angle of incidence of light, all of it apart from that the vehicle position is also ongoing changes, which also changes the idea angle can come. It is particularly disadvantageous that the damping effect may be continuous and brief changed in time, so that the driver irritates rather than is protected.

A certain light can also be problematic be the angle of incidence, for example through the headlights oncoming vehicles when driving at night. A complete Darkening the windshield would cause problems bring, so far so far at most a certain Applies matting or coating to these panes, to achieve a low level of damping.

The invention is based, too annoying, under an unfavorable and / or changing Angle incident light safely when passing through To dampen glass or similar.

The object is achieved in that the LCD cells taking into account the respective light angle of incidence through selectively switchable voltage fields influenced and aligned accordingly.  

When using this method, the LCD cells slanted like the slats of a window blind be so that the penetrating light is specifically attenuated can be, even if it is at an extreme angle passes through the glass pane or similar surface. The LCD cells in the pane turn up when the correspondingly running voltage field accordingly the angle of these two fields of tension. It can by choosing the respective areas of tension on both sides the glass pane the angle at which the LCD cells are align, be specified.

After an expedient development of the invention it is provided that on both sides of the glass sheet arranged voltage fields from side to side in parallel or out of phase according to the angle of incidence be switched to each other. About this phase shifted Switching the voltage fields, the angle is specified, under which the fields of tension run and under which align the LCD cells accordingly.

To easily adapt to the respective light fall or to reach the angle of the incident light, The invention provides that the angle of incidence of light is measured and the phase shift is adjusted electronically. The angle of incidence of light can vary over time Distances or according to the light intensity be checked, then the phase shift of the voltage change fields accordingly and the respective light adjust the fall angle.

While the procedure described earlier Particularly suitable for vehicles for the rear window or for comparable windows, the front window can to accommodate such a vehicle against glare the vehicle headlights are secured in that  the light intensity or the center of gravity is determined and the damping of the glass pane adjusted by sector Alignment of the liquid crystal cells is changed. The angle at which the Oncoming headlights light on the eyes the driver interacts to exactly that area and sector to bring about damping by applying a voltage. The remaining area of the windscreen, on the other hand, remains unaffected flows, so that advantageously the overall view of the driver is significantly improved because it is unimpaired the dazzling effect of the oncoming vehicle headlights can monitor the environment.

A device is used to carry out the method, in which liquid crystal cells are integrated into or assigned to a glass pane, which can be influenced via corresponding voltage fields, ie wires laid on or in the wire. Alignment of these LCD cells is achieved in that the glass pane with the integrated LCD cells is provided on both sides with the narrowest possible strips of conductive material, which are positioned close to one another and parallel to those on the opposite side and individually or in groups can be coupled to the voltage source. These strips can be placed under tension at the shortest distance from the edge of the pane and only for a very short time. An electronic control ensures that only one in five, tenth, or twentieth stripes is acted upon on each side of the pane at the same time. Are at the time X z. B. stripes 3, 13, 23, 33 , etc., it is at time X + 1, lines 4, 14, 24, 34 , etc. and at time X + 2, lines 5, 15, 25, 35, etc and on both sides of the glass pane. The LCD cells in the glass pane will now align themselves in the force field between the stripes on both sides of the glass pane. If the strips of the same number are under tension on both sides of the glass pane, the LCD cells will adjust themselves at right angles to the glass pane, since the strips under tension are exactly opposite. However, a phase shift is set so that, for. B. on the one side of the pane at the same time the lines 5, 15, 25, 35 , etc. and on the other side of the pane, the lines 7, 17, 27, 37 , etc. are under tension, so the LCD cells, by the staggered position of the strips 5 on one side and the strips 7 on the other side of the glass pane is predetermined. The LCD cells are therefore no longer at right angles to the surface of the glass pane, the damping effect for light passing through is shifted accordingly. Here, the invention also makes use of a property of the LCD material and the sluggishness in the perception of the human eye. The LCD material aligns itself with a force field faster than it swirls when the force field disappears. This somewhat sluggish behavior in the event of a loss of voltage results in a delay in reducing the light attenuation. Before the damping effect has completely disappeared, a new force field is available again by switching on the voltage. The sluggishness of the human eye also has a supportive effect similar to the perception of light from incandescent lamps.

Earlier it was mentioned that the connection the voltage is controlled by an electronic control, it is advantageous if the voltage source is a electronic control and a processor for the phases shifted or parallel voltage applied is associated with the stripes on both sides of the Glass pane is connected. About this electronic tax tion with processor can then simultaneously one at a time  desired change of the phase shift is set depending on how the driver feels and which he takes back by changing the phase shift wants to have seen.

An automatic with regard to the setting of the phases shift is achieved in that the electronic Control a the direction of the incident light averaging sensor is switched on. About this sensor can determine the direction of the incident light and via the processor and the electronic control then be taken into account.

According to the critical evaluation of the known methods and devices, it may be appropriate only in certain Divide or areas of a glass pane through the light to reduce casualness and if necessary only for a short time to do. This can help to eliminate glare rich by exactly facing only the blinding light source the eyes of the blinded person is covered by a surface exactly positioned on the connecting line on the disc. The location of this surface on the disc or in the disc is continuously corrected as well as the tuning of the damping property of the pane area to the angle of incidence of light. For this it is envisaged that the strips as a latticework of crossing conductors on both sides of the glass pane are arranged. These stripes are as above already mentioned parallel to each other at a very close distance arranged. This way, on each side of the disc created a Cartesian coordinate system, the Intersection points face each other on both sides of the disc.

It is advantageous if the strips are on one Side of horizontal and then at a distance of the edges are bent at right angles and to the neighboring one  Edge returning conductors and on the other side opposing conductors are formed. Stand the deflection points on both sides of the disc to the same Opposite time, the LCD material will move into the Slices from the point of deflection of one to the other Align the glass pane, which is a small damping point on the glass pane. Two overlap Strip angle on each side, so there will be four small ones Damping points result when each overlaps three angles corresponding to nine points etc. The advantage with this design of the latticework, that is always accurate the number of damping fields is created or generated that are required according to the sources of glare.

A simplified version of this provides that the stripes on one side of the glass pane vertically and arranged horizontally on the other side are. Here too there are intersection points or a Crossing field or damping field. Such training is advantageous when glare sources only in one plane be waiting. In contrast, with glare sources on several levels it cannot be ruled out that due to the geometric constraints more damping fields arise than sources of glare are.

In the way described, for example the window of the aircraft cockpit darkened sectorally be as long as this plane is on steady Course is located. The same applies to locomotives or for vehicles driving on straight motorways. Therefor would offer a controller that the damping field similar in size and position to that common today foldable and swiveling sun visor controls. At night journeys by motor vehicles, on the other hand, is sufficient Control not off. For this purpose, the invention provides that additional sensors to identify disturbing light  sources are provided and connected to the processor. About the sensor the number and position of the blend sources continuously determined and in relation to the known Position of the driver's head set, then the damping control surfaces on the pane accordingly. The driver only the occasional adjustment of the Damping surface in coordination with the individual values (Distance from the disc, height of the head accordingly height, possible distance between the eyes, etc.). In principle, there is also an adjustment option for Set a threshold below which none Damping is necessary.

The invention is characterized in that both with regard to the rear area as well as with the corresponding Training of the windshield area in vehicles u. Equipment switched off direct glare can be. This eliminates the need for human pupil to adapt to the direct glare put so that there is a significantly improved eyesight even in the dark. This is an increase related to traffic safety. With a cover only the glare sources themselves, e.g. B. only the headlight of oncoming vehicles, this remains and also whose surroundings are much more visible. Regarding the The driver can use the rear window when the sun is shining Adjust the disc in such a way that it falls diagonally from above Sunlight is optimally attenuated while its horizontal View remains unobstructed. At night he can do the disk like that adjust that the glare driving behind him Vehicles is minimized. Regardless of this remains him the opportunity by resizing the Tension to adjust the degree of damping.

Further details and advantages of the invention standes from the following description  the associated drawing, in which a preferred embodiment Example with the necessary details and Items is shown. Show it:

Fig. 1 shows a cross section through a sheet of glass with integrated fluid cells,

Fig. 2 keitskristallzellen suitable for coating glass sheets with integrated liquid,

Fig. 3 shows a further embodiment of the film shown in Fig. 2,

Fig. 4 is a lattice work for the sectoral damping of glass panes and

Fig. 5 shows another design of the lattice work in plan view.

Fig. 1 shows an oversized glass pane ( 1 ) with not shown in detail, integrated therein liquid crystal cells (LCD cells) ( 2 , 3 , 4 ). On both sides ( 5 , 6 ) of the glass pane ( 1 ), the narrowest possible strips ( 7 , 8 ) and exactly opposite ( 9, 10 ) are applied to the glass pane, via which a voltage field is generated when the liquid crystal cells ( 2 , 3 , 4 ) aligns accordingly.

Fig. 1 illustrates that the respective circuit of exactly opposite strips ( 7 , 9 ) or at an angle to each other strips ( 7 , 10 or 9 , 8 ) forces an inclined position of the LCD cells ( 2 , 3 , 4 ) can be, as indicated in Fig. 1. In this way, damping is achieved even if the light rays want to penetrate the glass pane ( 1 ) differently from the horizontal. The individual LCD cells then act as slats in a blind, which dampen the light beams accordingly or prevent them from passing through.

Fig. 2 shows a film ( 11 ) in which bubbles ( 12 ) are housed LCD cells. A conductive layer ( 14 ) is applied to the film ( 11 ) with the integrated LCD cells, via which the alignment of the individual LCD cells is effected. For this purpose, the conductive layer ( 14 ) and also the conductive layer ( 13 ) laid over it according to FIG. 3 are formed from a multiplicity of strips ( 7 , 8 or 9 , 10 ), although they are applied as a surface or film, can preferably be glued on.

In the apparent from Fig. 2 and Fig. 3 solution, it is possible to apply a corresponding film on a glass pane, so that appropriate already existing facilities can be converted without too much problems with the help of the invention, so as to protect against angled or to protect horizontal incidence of light or, more specifically, to dampen the incidence of light in such a way that there is no disability.

In that of Fig. 1, Fig. 2 and 3 apparent Embodiment Fig., The individual strips (7, 8, 9, 10) from the edge of the glass pane (1) ago in the shortest distance, and only for a very short time one after the other under tension be set. The electronic control, not shown here, ensures that on each side ( 5 and 6 ) of the glass pane ( 1 ), for example, only every 5th, 10th or 20th strip is acted on simultaneously. This makes it possible to influence the LCD cells located in between, as the angle of the strips ( 7 , 9 or 7 , 10 ) subjected to tension on both sides ( 5 , 6 ) of the glass pane specifies.

Fig. 4 and also Fig. 5 show an embodiment in which on both sides ( 5 , 6 ) of the glass sheet ( 1 ) a latticework ( 15 ) of intersecting strips ( 7 , 8 , 9 , 10 ) is arranged. These strips ( 7 , 8 , 9 , 10 ) are made of conductive material and are applied to the glass pane ( 1 ) running parallel and at a very close distance from one another. In this way, a Cartesian coordinate system is created on each side ( 5 , 6 ) of the glass pane ( 1 ), the points of intersection of which lie opposite one another on both sides ( 5 , 6 ) of the glass panes, which is illustrated by FIG. 4.

From the edges of the glass pane ( 1 ), voltage is now applied to the strips ( 7 , 8 , 9 , 10 ) for each side ( 5 , 6 ) of the glass pane, in such a way that the current flow on the side ( 6 ) of the glass pane ( 1 ) over the strip ( 7 ) from the edge ( 16 ) to the bend of the conductor ( 7 ), in order to then be guided vertically down to the edge ( 17 ). On the other side ( 5 ) of the glass pane ( 1 ), the current flow is led from the edge ( 18 ) to the center to the kink of the strip ( 9 ), in order to then flow to the edge ( 19 ). If the deflection points on both sides ( 5 , 6 ) of the glass pane ( 1 ) face each other at the same time, the LCD material in the glass pane ( 1 ) will move from the deflection point of one side to the other ( 5 , 6 ) align, resulting in a small damping point on the glass pane ( 1 ). If two stripe angles on each side ( 5 or 6 ) overlap, there will be four small damping points, with the overlap of three angle stripes corresponding to nine points, etc.

In Fig. 5 the possibility is shown, on one side (5) to act on only a corresponding number of vertical strips (9) and on the other side (6) of the glass pane (1) a corresponding number of horizontally extending guides (7 ). Here, too, there are intersection points or an intersection field or damping field and thus a sectoral damping of a substantially larger pane area.

With the device described, it is also possible to Writings and drawings on such a glass pane play, this simply by switching on and off of small line areas is realized. With a appropriately skillful control and the necessary Processor is any representation of characters and drawings and also of moving pictures possible, if the specifications from an electronic storage system be retrieved.

Claims (11)

1. A method for changing the attenuation of the glass panes or similar surfaces penetrating light at different angles of incidence, in which the glass pane associated liquid crystal cells (LCD cells) are influenced in accordance with the requirements via electrical voltage fields, characterized in that the LCD cells taking into account the respective light incidence angle influenced by switchable voltage fields and these are aligned accordingly. 2. The method according to claim 1, characterized, that the arranged on both sides of the glass pane Tension fields from side to side parallel or the light Angle of incidence corresponding to each other out of phase be switched. 3. The method according to claim 1 and claim 2, characterized, that the angle of incidence is measured and the phase shift exercise is electronically adjusted. 4. The method according to claim 1, characterized, that the light intensity or the light center is determined and the damping of the glass pane adjusted by sector Alignment of the liquid crystal cells is changed. 5. Apparatus for carrying out the method according to claim 1 or one or more of the subordinate claims, with the glass pane associated with the electrical lines, an energy source and the glass pane assigned, via the generated voltage fields alignable liquid crystal cells (LCD cells), characterized in that the Glass pane ( 1 ) with the integrated LCD cells ( 2 , 3 , 4 ) on both sides ( 5 , 6 ) are provided with the narrowest possible strips ( 7 , 8 , 9 , 10 ) of conductive material, which are close together and parallel to them positioned on the opposite side in each case and which can be coupled individually or in groups to the voltage source. 6. The device according to claim 5, characterized in that the voltage source is assigned an electronic control and a processor for phase-shifted or parallel voltage application, with the strips ( 7 , 8 , 9 , 10 ) on both sides ( 5 , 6 ) of Glass pane ( 1 ) is connected. 7. The device according to claim 5 and claim 6, characterized, that the electronic control a the direction of the one falling light detecting sensor is switched on. 8. The device according to claim 5, characterized in that the strips ( 7 , 8 , 9 , 10 ) as a latticework ( 15 ) of intersecting conductors on both sides ( 5 , 6 ) of the glass pane ( 1 ) are arranged. 9. The device according to claim 8, characterized in that the strips ( 7 , 8 , 9 , 10 ) on one side ( 5 ) of horizontally extending and then at a distance from the edges ( 16 ) bent at right angles and to the adjacent edge ( 17 ) returning conductors and on the other side ( 6 ) opposing conductors are formed. 10. The device according to claim 8, characterized in that the strips ( 7 , 8 , 9 , 10 ) on one side ( 5 ) of the glass sheet ( 1 ) are arranged vertically and on the other side ( 6 ) horizontally. 11. The device according to claim 8, characterized, that additional sensors to identify disturbing Light sources are provided and connected to the processor are.