DE102007055497A1 - Optical sensor e.g. brightness sensor, for motor vehicle, has optic body rotatable against optical transmission and receiving units, so that transmission and receiving units are assignable to different light conductor arrangements - Google Patents

Abstract

The invention relates to an optical sensor for a motor vehicle, comprising optical transmission elements which radiate light into a vehicle window and optical reception elements which detect light reflected from the vehicle window, and an optical system which forms a plurality of light guides which are arranged between the vehicle window and the transmission window. and receive elements form a plurality of light paths, which are adapted to different slice thicknesses, wherein the optical body with respect to the optical transmitting and receiving elements is rotatable, so that the transmitting and receiving elements different optical fiber assemblies are assigned.

Description

The The invention relates to an optical sensor for a motor vehicle, with optical Transmitting elements that radiate light in a vehicle window and with optical receiving elements, which reflected from the vehicle window Capture light, and with an optic body containing multiple light guides formed between the vehicle window and the transmitting and receiving elements form multiple light paths that are at different slice thicknesses are adjusted.

at optical sensors that reflect the light on a vehicle window use, is the arrangement of the optical elements, especially the location the optical transmitting and receiving elements or the angular position of the Light guides to each other, sensitive to the properties of the vehicle window and especially the slice thickness dependent. As the thickness of vehicle windows is not uniform, is the same optical in itself Sensor for manufacture different types of vehicles in different variants. Due to the large number of required sensor variants arises considerable manufacturing and logistical effort.

From the German patent application DE 102 12 269 A1 For example, a rain sensor is known which has a plurality of measurement paths extending through a disk, the measurement paths being optimized for different thicknesses of the disk.

The The invention presented here aimed to provide an optical sensor for a To create a motor vehicle that is particularly versatile in a simple structure is usable.

These Task is inventively characterized solved, that the optic body across from the optical transmitting and receiving elements is rotatable, so that the transmission and reception elements different light conductor arrangements are assignable.

For this For example, it may be provided that one or more light emitters and light receiver on a circuit carrier are firmly positioned and several, different light paths forming optical fibers are arranged on the optical body.

Advantageous is it when the optic body or at least the arrangement of the optical fibers on the optical body approximately rotationally symmetrical is trained. The optic body can be arranged in several positions relative to the circuit carrier be, so that each best adapted to a vehicle window Optical fiber assemblies coupled to the transmitting and receiving elements becomes. This makes it possible the same optical sensor with equally good functionality to use different thicknesses of vehicle windows.

The Adaptation of an optical fiber route to a vehicle window is characterized given that the angular position of light guides, as well as the distance from Fiber optics selected each other so is that the light from a light emitter by means of reflection on the vehicle window optimally directed to a light receiver becomes. A good parameter to handle here is the distance the transmitter and receiver side Light guide to each other.

to Adaptation of an optical sensor to different vehicle windows will at least one, for the thickness of the respective vehicle window suitable light path selected. The selection can be made, for example, by the electronics belonging to the sensor respectively. For this purpose, all light paths of the optical sensor with equipped with optical transmission and reception elements. But only the or the light emitter and light receiver are activated for suitable light paths or only the signals of selected ones Light paths used for evaluation.

A advantageous development of such an optical sensor is in it, an additional one provide optical receiving element that with no transmitting element interacts and that the luminance in the apron of the vehicle detected. The receiving element can, in particular part of a optionally be on the PCB fastener stretcher sensor cluster, the local through the inner recess close to the vehicle window is positioned and provides more sensory information.

One Such brightness sensor is intended in each relative position of optical body and circuit carrier each other can detect the luminance in front of the vehicle. For this it is advantageous if the brightness sensor for each possible relative position respectively a light guide is assigned, the ambient light on the receiving element passes.

A further embodiment provides that the additional Optical fiber adapted to differently inclined vehicle windows are.

A particularly advantageous possibility for mounting the optical sensor on the vehicle window is to arrange the optical body around the foot of a mirror attached to the vehicle window mirror. Since the mounting surface of the mirror base is thus used for fastening the optical sensor, the optical sensor can be arranged in a particularly space-saving manner on the vehicle window. Is particularly advantageous Also, that the mirror can also be used for mechanical attachment of the optical sensor, such as in a connected to the mirror base spring element presses the optical body to the vehicle window.

advantageous versions and further developments of the erfindungemäßen optical sensor are in the dependent claims cited. The following are exemplary embodiments the invention are illustrated with reference to the drawing and explained in more detail. Show it

1 a plan view of an optical body with schematically illustrated light paths,

2 a side view of the optic body,

3 schematically illustrated light paths through the optical body in two different thickness vehicle windows,

4 a sensor arrangement in an exploded view,

5 to 7 possible arrangements of optical elements relative to the optical body,

8th and 9 an arrangement of an optical body to a mirror base.

The 1 shows an optic body ( 1 ) in a plan view. The optic body ( 1 ) is formed as an integrally molded plastic body, which is transparent at least for the light wavelengths emitted by transmitting elements.

The optic body ( 1 ) has the shape of a circular disk or, as shown here, a circular ring with an inner recess ( 2 ).

Along the circumferential direction of the optic body ( 1 ) are eight optical fiber assemblies ( 3a . 3b ) integrally formed. Each of the optical fiber assemblies ( 3a . 3b ) corresponds in shape to two converging in the direction of the circular disc cylindrical Lichtodererstümpfen whose longitudinal axes are offset by approximately 90 ° from each other. The free end faces of these light guide cylinders each form an integrally formed lens ( 7a . 7b ) for Lichtein- or light extraction. The eight light conductor arrangements ( 3a . 3b ) are on the optic body ( 1 ) offset by approximately 45 ° from each other, wherein the distance between adjacent light guide assemblies ( 3a . 3b ) varies with each other.

Optical fibers of adjacent optical fiber assemblies ( 3a . 3b ) each form a light path ( 4 ) out. By dashed and dotted lines are in the 1 eight possible light paths ( 4 ). The light trails ( 4 ) final endpoints ( 5 ) can be occupied in various ways with optical transmitting and receiving elements, which is based on the 5 to 7 will be explained in more detail.

A light path ( 4 ), which the 1 in the projection shows the 2 in a side view of the optic body ( 1 ). One above the optic body ( 1 ), schematically illustrated transmitting element (S) radiates over the lens ( 7a ) Light in the axial direction in an optical waveguide of the light guide arrangement ( 3a ) one. This light is at the, here only partially shown, vehicle window ( 6 ) in the direction of the light guide arrangement ( 3b ) totally reflected and over the lens ( 7b ) at the light guide arrangement ( 3b ) directed to the receiving element (E). In case of wetting or soiling of the vehicle window ( 6 ) changes the incident on the receiving element (E) light intensity, which is detected by an evaluation, not shown.

As the 1 shows, the optic body ( 1 ) not just one, but a total of eight usable light paths ( 4 ). Of course, the optical body ( 1 ) may also be formed with fewer or more light paths. Through the different light paths ( 4 ), the optical sensor can be easily adapted to different slice thicknesses.

As the 3 clarifies, this is done in a particularly advantageous manner by different distances of adjacent optical fiber assemblies ( 3a . 3b respectively. 3a . 3b ' ). If the Lichtein- and -ausfallwinkel on the vehicle window ( 6a respectively. 6b ), regardless of their thickness, have a predetermined value and should also the light beam perpendicular to the end face of a light guide and thus refraction in the optical body ( 1 ), the distance between the optical fibers belonging to the transmitting and receiving elements (S, E) is corresponding to the respective thickness of the vehicle window ( 6a respectively. 6b ).

As the 3 shows this distance at the thicker vehicle window ( 6b ), which is shown here in dashed lines, significantly larger than in the thinner vehicle window ( 6a ).

Despite the different distances between the light guides ( 3a . 3b respectively. 3a . 3b ' ) at different light paths they can generally interact with the same pairs of transmitting and receiving elements (S, E), without these would be repositioned to each other. This is in the 3 represented by the two-dimensionally symbolized transmitting and receiving elements (S, E), which indicate that the transmission element (S) no point light source is used and that the reception Element (E) is designed for a flat detection range. It should also be noted that the differences in the thickness of the discs ( 6a . 6b ) for clarity in the 3 are shown exaggeratedly large.

Of course you can if necessary, also differently spaced combinations of Transmitting and receiving elements are provided, which in turn with in each case a plurality of geometrically differently configured light paths can be combined are.

The Indian 1 illustrated optical body ( 1 ) can be used with eight different light paths ( 4 ) be optimally adapted to eight different thicknesses. Alternatively, however, several light paths ( 4 ) geometrically similar and thus redundant. In addition, in addition to the at least one optimally adapted light path, even further light paths can be used, and preferably the light stretches adapted to the respective slice thickness at the next best.

The Adjustment of the sensor to different slice thicknesses can be so be made that all start and end points of the light paths equipped with optical transmitting and receiving elements and only the most suitable Transmitting and receiving elements electrically connected or activated be, or only their signals for the generation of a measuring signal can be used.

These solution However, it still requires a specification of electrical parameters, which for example about the positions can be done by dip switches, or by a programmer Adaptation of an evaluation program to a planned slice thickness.

There Such settings are relatively expensive and error prone can, it is more advantageous to activate certain light paths to make a purely mechanical way. For this purpose, the optical body in terms its optical fiber assemblies at least approximately rotationally symmetrical and in several relative positions to the transmitting and receiving elements to arrange.

are the transmitting and receiving elements are arranged on a circuit carrier, so this means that the optic body in several different Positions opposite the circuit carrier is positionable.

A schematically illustrated construction of an optical sensor is shown in the exploded view of FIG 4 seen. The sensor consists of the optic body ( 1 ) and the circuit carrier ( 8th ), of two housing parts ( 9a . 9b ). A first housing part forms a housing body ( 9a ), which is fastened to an unillustrated vehicle window. Over an opening ( 10 ) in the housing body ( 9a ) is the optic body ( 1 ) optically coupled to the vehicle window directly or via a suitable Ankoppelmedium. The housing body ( 9a ) is by means of a housing cover ( 9b ) closed.

The inner recess ( 2 ) of the optic body ( 1 ), a on the circuit carrier ( 8th ) arranged sensor cluster ( 14 ) to implement further optional sensor functions near the vehicle window. Such sensor functions may include in particular global ambient light detection, sun position detection, automatic headlight activation, oncoming vehicle detection with automatic high beam light shutdown, as well as optical data transmission systems, for example for toll collection.

With the circuit carrier ( 8th ) are further connected a total of four optical transmitting and receiving elements ( 11 ) to which the optical fiber assemblies ( 3 ) on the optic body ( 1 ) are alignable.

It is advantageous if the optical elements ( 11 ) not exactly within the theoretical foci of the optical fiber assemblies ( 3 ) but are at a slight distance of typically a few tenths of a millimeter behind. This slightly "fuzzy" light input and output reduces the sensitivity to component and positioning tolerances.

The position of the circuit carrier ( 8th ) relative to the two housing parts ( 9a . 9b ) is fixed, while the optical body ( 1 ) relative to the housing parts ( 9a . 9b ) or with respect to the circuit carrier ( 8th ) can take several rotational relative positions. The optic body ( 1 ) is therefore during installation depending on the thickness of the pane relative to the circuit carrier ( 8th ). Thereafter, the entire sensor assembly is optically connected to the vehicle window.

The number of mechanically definable relative positions ideally corresponds to the count of the rotational symmetry of the optical waveguide arrangements ( 3 ) on the optic body ( 1 ), so that the optic body ( 1 ) is in any relative position in a functional position to the optical transmitting and receiving elements.

So that the optical body can be easily brought into precise positions when assembled, he has positioning aids, the beispielswei in at least one molded notch ( 12 ) or nose, with a nose or notch on the circuit carrier ( 8th ) or on a housing part ( 9a . 9b ) and the possible relative positions of the optic body ( 1 ).

pairs of optical fiber assemblies form due to their geometric arrangement, in particular by different mutual distances, light paths with different optical properties. Alternatively, though also several identically formed pairs of optical fibers to create be provided redundant light paths.

In this regard, advantageous embodiments are in the 5 to 7 shown. In all examples shown, the optic body ( 1 ) eight optical fiber assemblies ( 3 ), which along a circumferential direction on the annular optic body ( 1 ) are arranged. Neighboring optical fiber assemblies ( 3a . 3b ) are each arranged at an angle of approximately 45 ° to each other, wherein the distances between adjacent light guide arrangements ( 3a . 3b ) vary slightly.

In principle, it is possible to provide all light paths with transmitting and receiving elements (S, E), as the 1 suggests, and to adapt to the existing in a vehicle window, only to take the best adapted to the thickness of the disc light path in operation. As a result, however, is the cost of optical elements for the result obtained in evaluable light paths in any favorable ratio.

To a much more favorable result leads here in the 5 illustrated arrangement. Here is a single light path ( 4 ) equipped with an optical transmitting element (S) and an optical receiving element (E). The selection of the light path ( 4 ), ie the pair of irradiated light conductor arrangements ( 3a . 3b ) is done by the arrangement of the optical body relative to the transmitting and receiving elements (S, E) during assembly of the optical sensor. Since the optical sensor has a basically simple structure, this assembly can be done simultaneously with the attachment to the vehicle window.

Assuming that the distances between adjacent light guide arrangements ( 3a . 3b ) are each different, so the optical sensor by selecting the transmitted light path ( 4 ) are optimally adapted to eight different pane thicknesses.

According to the 6 also two light paths ( 4 ) at the same time be in operation, which may for example be arranged parallel to each other. Here, the two light paths ( 4 ) be designed for similar thicknesses, so that here the best and the second best adapted light path is used.

The two parallel light paths ( 4 ) can also be symmetrical, ie with equidistant light conductor arrangements ( 3a . 3b ) be formed. For the entire optic body ( 1 ) this would result in four different pairs of similar light paths ( 4 ). Each of the four different light paths ( 4 ) is thus duplicated, whereby a redundant detection of optically recognizable events is possible.

In the in the 7 illustrated embodiment even four light paths ( 4 ) used for a measurement. It is particularly advantageous that only two optical transmitting elements (S, S ') and two optical receiving elements (E, E') are required for this purpose. This can be achieved by the two transmitting elements (S, S ') are operated clocked and thereby alternately on both receiving elements (E, E') send. This achieves a high degree of redundancy with little effort.

By a rotation of the optic body ( 1 ) by 45 ° can also be made an adjustment to at least one further slice thickness, in which the four previously unused light paths are used.

In the illustrated optical body ( 1 ) are near the inner recess four optical fibers ( 13 ) recognizable that are not assigned to any light path. These light guides ( 13 ) function to direct light from the vehicle surroundings to another unillustrated optical receiver, thus forming part of a brightness sensor. Because the optic body ( 1 ) is also positioned differently with respect to this further receiving element, at least as many optical fibers ( 13 ) on the optic body ( 1 ), as there are provided rotational positions of the optical body relative to the circuit carrier. Thus, in each rotational position of the optic body ( 1 ) the receiving element of the brightness sensor, a light guide ( 13 ).

An assembly-technically advantageous embodiment of an optical sensor is in the 8th and 9 shown schematically. The optic body ( 1 ) is in this case arranged around the foot of an inner mirror around and uses its mounting space on the vehicle window with. At the same time, the mirror base ( 15 ) for the mechanical fastening of the optic body ( 1 ) used. As a result, a particularly space-saving arrangement of the optic body ( 1 ) reached at the vehicle window.

In this embodiment, no sensor is provided, which the inner recess ( 2 ) of the Op tikkörpers uses, so that the recess for fixing the optic body ( 1 ) on the mirror base ( 15 ) is available. The recess ( 2 ) of the optic body ( 1 ) is about the mirror base ( 15 ) until the optic body ( 1 ) comes to the vehicle window to the plant.

At the mirror base is a very simple way a spring element ( 16 ), for example in the form of a bar spring, which fixes the optical body ( 1 ), preferably with a gel pad as the coupling medium ( 21 ), presses against the vehicle window.

The possibility of forming the gel pad in such a way that only the surfaces of the optic body which are necessary for the coupling (FIG. 1 ) are occupied. By reducing the contact surface, it becomes possible to use a spring element ( 16 ) provided with a relatively small spring force.

As the 8th and 9 show is the spring element ( 16 ) as a substantially annular sheet metal strip ( 18 ), which has at least two molded-on arms ( 17 ) in the radial direction of the sheet metal strip ( 18 ) stand out. The annular metal strip ( 18 ) is on a mirror base ( 15 ), which by means of an adhesive layer ( 20 ) is attached to the vehicle window. Specifically, in this embodiment, the annular metal strip ( 18 ) between the mirror base ( 15 ) and the mirror neck ( 23 ), wherein the mirror base ( 15 ) and the mirror neck ( 23 ) by means of a resilient or latching mirror fastening device ( 22 ) are interconnected.

The end sections of the arms ( 17 ) of the spring element ( 16 ) press the optic body ( 1 ) against the vehicle window. Around the mirror base is the optic body ( 1 ) circulating through an annular housing ( 19 ).

1

optical body

2

recess

3, 3a, 3b, 3b "

Optical fiber arrangements

4

light trails

5

endpoints

6 6a, 6b

vehicle window

7a, 7b

lenses

8th

circuit support

(9a, 9b)

housing parts

9a

housing body

9b

housing cover

10

opening

11

optical Transmit and receive elements

12

score

13

optical fiber

14

sensor cluster

15

mirror

16

spring element

17

poor (on spring element)

18

ring-shaped sheet metal strip

19

casing

20

adhesive layer

21

coupling medium

22

Mirror mounting device

23

mirror neck

e, E ''

receiving elements

S, S ''

transmitting elements

Claims (12)

An optical sensor for a motor vehicle, comprising optical transmitting elements that radiate light into a vehicle window and with optical receiving elements that detect light reflected from the vehicle window, and with an optical body that forms a plurality of optical fibers that have a plurality between the vehicle window and the transmitting and receiving elements Form light paths which are adapted to different slice thicknesses, characterized in that the optic body ( 1 ) relative to the optical transmitting and receiving elements (S, E) is rotatable, so that the transmitting and receiving elements (S, E) different optical fiber assemblies ( 3a . 3b . 3b ' ) are assignable. Optical sensor according to claim 1, characterized in that for each slice thickness at least two adapted aligned light paths ( 4 ) are provided. Optical sensor according to claim 1, characterized in that for the thickness of the actually existing vehicle window ( 6 ) best-adapted light path (s) ( 4 ) is in operation. Optical sensor according to claim 3, characterized in that additionally for the thickness of the actually existing vehicle window ( 6 ) on the second best adapted light path (s) ( 4 ) is in operation. Optical sensor according to claim 3 or 4, characterized in that additionally adapted to the next largest slice thickness (s) light path (s) ( 4 ) is in operation. Optical sensor according to Claim 1, characterized in that the arrangement of the optical waveguide arrangements ( 3 . 3a . 3b . 3b ' ) on the optic body ( 1 ) is at least approximately rotationally symmetrical. Optical sensor according to claim 1, characterized in that the optical body ( 1 ) additional light guides ( 13 ) for at least one optical receiving element to which no transmitting element are ordered. Optical sensor according to claim 7, characterized in that the additional optical fibers ( 13 ) are adapted to differently inclined vehicle windows. Optical sensor according to one of the preceding claims, characterized characterized in that the optical sensor forms a rain sensor. Optical sensor according to claim 7, characterized that the optical sensor a rain sensor in combination with a Brightness sensor trains. Optical sensor according to claim 1, characterized in that the optical body ( 1 ) around a mirror attached to the vehicle window ( 15 ) is arranged around. Optical sensor according to claim 1, characterized in that one with the mirror ( 15 ) connected spring element ( 16 ) the optic body ( 1 ) presses against the vehicle window.