DE102017121479B4 - Protective screen for an optoelectronic sensor, in particular a camera, and sensor system - Google Patents

Abstract

Protective screen (5) for protecting an optoelectronic sensor device (2) in an optoelectronic sensor system, comprising:- a transparent carrier screen (51),- an anti-glare layer (54) which is applied to the carrier screen (51) to avoid or reduce a glare effect, wherein the anti-glare layer (54) is designed to reduce glare caused by light incident at an angle from the side;- a heating layer (55) applied to the carrier screen (51) for controllable heating of the protective screen (5),- a protective layer (56) which is designed to prevent the adhesion of dirt particles.

Description

Technical area

The invention relates to optoelectronic sensor devices, such as cameras or optical sensors, such as laser sensors, for outdoor use. In particular, the present invention relates to measures for protecting optoelectronic sensor devices against environmental influences and ensuring interference-free transmission of light to be detected to an optoelectronic sensor device.

Technical background

In vehicle applications in particular, optoelectronic sensor devices are used to appropriately detect or sense a vehicle's surroundings. For example, camera systems can be arranged in or on the vehicle to capture images of the vehicle's surroundings. Furthermore, laser-based distance measuring devices can be used to determine distances to surrounding objects.

Such optoelectronic sensor devices in vehicle applications must be protected from environmental influences, as with all sensor systems used outdoors. In the case of optical sensor systems, it is also necessary to ensure a constant and unaffected degree of transmission so that the incidence of light on the sensor device is not obstructed. For example, the light transmission through a protective device designed as a pane can be impaired by fogging, frost, dirt or glare. These effects cannot usually be compensated for with electronic compensation measures for the optoelectronic sensor devices.

In this regard, protective screens are known which, for example, have heatable coatings to protect against fogging or frost.

For example, the publication WO 2012/004279 A1 A transparent pane with a conductive coating is known for delivering heating power in a heating field provided with the conductive coating.

As a rule, the protective screens only have a maximum of one coating in order to provide sufficient protection against fogging, against dirt, against glare or the like.

The publication DE 198 05 000 A1 discloses an optical sensor device for motor vehicles with an optical sensor arranged behind a window of the motor vehicle, separated from the vehicle surroundings, for determining measured variables related to the vehicle surroundings and with an optics associated with the sensor. The window has a layer with variable light transmittance in the passage area of the radiation directed at the optics and/or the optics themselves. Furthermore, the window can be heated in the area in which it is designed as an optics.

The publication EN 10 2009 004 045 A1 discloses a pane with a heatable, optically transparent pane segment comprising: an upper pane, a heatable, optically transparent intermediate layer and a lower pane, wherein the intermediate layer comprises an upper adhesive film, a heating element, an electrically conductive connection to the heating element and a lower adhesive film.

The publication EN 102012 018 001 A1 discloses a transparent pane for a motor vehicle comprising a viewing area and an electrically heatable sensor area, wherein the transparent pane has a transparent, electrically conductive layer of the electrically heatable sensor area, which extends at least within the electrically heatable sensor area, and the transparent pane comprises sensor area busbars for current distribution to the electrically conductive layer of the electrically heatable sensor area, between which the electrically heatable sensor area is arranged, wherein the sensor area busbars are electrically conductively connected to the electrically conductive layer of the electrically heatable sensor area.

The publication EN 10 2004 001 425 A1 discloses an optically functional assembly containing an optical functional element working with an optic and a housing enclosing the same, wherein an object-side part of the optic acting as an optical lens or the entire optic of the assembly is designed as an integral part of the housing of the assembly.

It is therefore an object of the present invention to provide a protective screen for an optoelectronic sensor device which ensures comprehensive protection against environmental influences and reliably enables a consistently high degree of transmission of light from the vehicle environment to the sensor device.

Disclosure of the invention

This object is achieved by the protective screen for covering an optoelectronic sensor device according to claim 1 and an optoelectronic sensor system according to the independent claim.

Further embodiments are specified in the dependent claims.

• - eine transparente Trägerscheibe,
• - eine Antiblend-Lage, die zur Vermeidung oder Reduzierung eines Blendeffekts auf der Trägerscheibe aufgebracht ist;
• - eine auf die Trägerscheibe aufgebrachte Heiz-Lage zur regulierbaren Beheizung der Schutzscheibe,
• - eine Schutz-Lage zur Vermeidung der Anhaftung von Schmutzpartikeln.

According to a first aspect, a protective screen is provided for protecting an optoelectronic sensor device in an optoelectronic sensor system, comprising:

• - a transparent carrier disc,
• - an anti-glare layer applied to the carrier pane to prevent or reduce a glare effect;
• - a heating layer applied to the carrier disc for adjustable heating of the protective disc,
• - a protective layer to prevent the adhesion of dirt particles.

The above protective screen has a multiple coating, with an anti-glare layer, a heating layer and a protective layer being applied in particular to a transparent carrier screen. These layers or coatings enable the protective screen to be heated, automatically kept clean and the glare effect to be reduced. In this way, a protective screen for an optoelectronic sensor device can be provided which can also be used in an improved manner under adverse environmental conditions, such as high humidity, low air temperature, high levels of contamination or particle load and strong or oblique incidence of light.

Furthermore, the carrier disk can be provided with an opaque region by means of an opaque masking, in particular a black print, such that one or more detection windows are formed, wherein the heating layer is in particular applied directly to the opaque masking.

In particular, the one or more detection windows can be provided with a color filter.

In particular, at least one of the detection windows can have a rectangular cross-section with rounded corners.

Furthermore, the anti-glare layer can be applied directly to the carrier disc or to the heating layer applied to the carrier disc.

According to one embodiment, the protective layer can be applied to the anti-glare layer.

Furthermore, the heating layer can be formed with an electrically conductive coating with a negative temperature coefficient, wherein the electrically conductive coating is formed by a semiconductor heating varnish.

According to one embodiment, the heating layer can be electrically contacted by at least two contact surfaces, wherein in particular the contact surfaces are contacted with electrical contact pins which are led out at predetermined positions on the side of the protective screen, in particular at positions opposite one another

Furthermore, the protective pane can be provided with a seal surrounding an outer edge of the carrier pane, which protrudes on both sides beyond the main surfaces of the protective pane, wherein the seal is in particular formed with a separate sealing part on each of the main surfaces of the protective pane.

The protective screen may be provided with a seal surrounding an outer edge of the carrier screen, which is constructed from sealing parts each arranged on a main surface of the protective screen.

Furthermore, the carrier disk can be flat or can be designed in the shape of a convex lens and have a curved surface.

According to a further aspect, an optoelectronic sensor system, in particular a camera system, is provided with the above protective screen.

Furthermore, the above optoelectronic sensor system can be provided with an optoelectronic sensor device in a housing, wherein the housing has an opening which closes the protective screen.

An ultrasonic transmitter may be provided which engages the side of the protective screen in order to protect the protective screen from contamination on the surface of the protective screen by subjecting it to an ultrasonic vibration.

Furthermore, an electrical heating supply source can be provided, which is connected to the electrically conductive heating layer of the protective screen in order to enable the protective screen to be heated by means of current.

Short description of the drawings

• 1 eine schematische Querschnittsdarstellung eines Kamerasystems;
• 2 eine Querschnittsansicht durch eine erfindungsgemäße Schutzscheibe;
• 3 eine Draufsicht auf die Schutzscheibe der 1 zur Veranschaulichung einer möglichen Form einer Fensterblende; und
• 4 eine Querschnittsdarstellung einer mit einer Dichtung versehenen Schutzscheibe.

Embodiments are explained in more detail below with reference to the attached drawings. They show:

• 1 a schematic cross-sectional view of a camera system;
• 2 a cross-sectional view through a protective screen according to the invention;
• 3 a top view of the protective screen of the 1 to illustrate a possible form of a window blind; and
• 4 a cross-sectional view of a protective screen provided with a seal.

Description of embodiments

1 shows a camera system as an example of an optoelectronic sensor system 1. The camera system 1 has an optoelectronic sensor device 2 in the form of a camera module. Alternative optoelectronic sensor devices can include laser-based distance sensors or the like.

The camera module 2 is located in a closed housing 3, which has an opening 4 in the detection direction E of the camera module 2. The opening 4 is covered by a transparent protective screen 5, which seals the housing 3 essentially in a dirt-tight and moisture-tight manner, so that the camera module 2 is protected from external influences, such as the ingress of dirt or moisture.

The protective screen 5 is in cross section in 2 The protective screen 5 comprises a transparent carrier screen 51 which is provided with an opaque masking 52, in particular printed with a black print, in order to create one or more detection windows 53. The carrier screen 51 can be made of glass. Other transparent materials can also be used if necessary.

By providing the carrier disk 51 with the non-transparent masking 52 with several detection windows 53, a larger protective disk 5 can be provided for several optoelectronic sensor devices 2 in the housing 3.

In 3 A possible form of such a detection window 53 is shown in an otherwise round protective screen 5. The detection window 53 in the area made opaque by the masking 52 has a substantially rectangular shape in which the corners are rounded.

The carrier disk 51 is then provided with an anti-glare layer 54 to prevent a glare effect. The anti-glare layer 54 serves to reduce glare caused by light incident at an angle from the side. The material of the anti-glare layer 54 can comprise various metal oxides, which are applied, for example, by an evaporation process. Such anti-glare layers 54 and their application to a substrate are known from the prior art and can be applied to various types of carrier disks 51.

The anti-glare layer 54 is followed by a dirt-repellent and scratch-resistant protective layer 56, which prevents dirt from adhering to the protective screen 51 and provides scratch protection. For this purpose, the cover layer of the anti-glare layer 54 should be compatible with the material of the protective layer 56 so that the protective layer 56 adheres to the anti-glare layer 54. In particular, the protective layer 56 can be formed with a coating with oleophobic and hydrophobic nanopolymers. The nanomaterial used for this can, for example, be vapor-deposited.

A heating layer 55 is provided, which is applied to the carrier disk 51, in particular to the masking 52. The heating layer 55 can be made of a semiconductor heating lacquer. Due to the negative temperature coefficient of the semiconductor heating lacquer, it is self-regulating when energized, so that the resulting heating power is essentially determined by the thickness of the heating layer 55 and the applied electrical heating current. The heating layer 55 is as in 2 shown preferably provided between the carrier pane 51 and the anti-glare layer 54, so that fogging or frost formation on the protective pane 5 can be eliminated by heating the protective pane 5. In particular, the heating layer 55 can be applied to the masking 52.

In this way, a protective screen 5 can be formed in which special properties with regard to transmittance are achieved by an anti-glare and anti-pollution effect.

The sensor system 1 can also be provided with an ultrasonic transmitter 6, which engages the side of the protective screen 5 in order to protect the protective screen 5 from contamination on the surface by applying an ultrasonic vibration. surface of the protective screen 5 or to repel it.

Furthermore, an electrical heating supply source 7 can be provided which is electrically connected to the heating layer 55 in order to enable heating of the protective screen 5 by supplying current. In this way, the protective screen 5 can be freed of fogging or frost or a deposit of fogging or frost can be avoided.

To contact the heating layer 55, at least two contact surfaces 57 can be provided on the heating layer 55, wherein in particular the contact surfaces 57 are contacted with electrical contact pins 58, which are led out at predetermined positions to the side of the protective screen 5, in particular at positions opposite one another. For example, the contact surfaces 57 can be designed opposite one another, and the contact pins 58 extend radially outward from them. This enables positioning that allows a defined installation of the protective screen 5. The positions of the contact pins 58 can be arranged in particular with respect to the alignment of the detection window.

The protective screen 5 can be flat. Alternatively, the protective screen 5 can be designed in the shape of a converging lens and have a curved surface. The curved surface is preferably provided with the coatings 54 to 56.

In order to protect the seal of the housing 3 from the ingress of dirt when installing the protective screen 5 in the sensor system 1, the outer edge of the protective screen 5 can be cut as shown in 3 shown, surrounded by a seal 8. The 4 shows a cross-sectional view of the protective screen 5 to illustrate the arrangement of the seal 8.

The seal 8 can be attached to the protective screen 5 in two steps. In a first step, the side of the carrier screen 51 opposite the coatings 54 to 56 can be provided with a circumferential first sealing part 81 that overlaps the edge of the protective screen 5. The first sealing part 81 can be applied directly to the carrier screen 51 using a 3D printing process, for example. Alternatively, the first sealing part 81 can be formed separately and the protective screen 5 can then be inserted. Polyurethane in particular can be used as the sealing material.

A circumferential second sealing part 82 can then be formed in order to produce the seal 8 surrounding the edges of the protective screen 5. The protective screen 5 thus provided with the seal 8 can then be further processed in a simple manner in production, since the protective screen 5 can be touched at the sealing edge without touching the surface of the protective screen 5 and thus remains free of fingerprints.

List of reference symbols

1

Sensor system

2

Sensor device

3

Housing

4

opening

5

Protective screen

51

Carrier disc

52

non-transparent masking

53

Capture window

54

Anti-glare layer

55

Heating position

56

Protective position

7

electric heating supply source

8

seal

81

first sealing part

82

second sealing part

Claims (15)

Protective screen (5) for protecting an optoelectronic sensor device (2) in an optoelectronic sensor system, comprising: - a transparent carrier screen (51), - an anti-glare layer (54) which is applied to the carrier screen (51) to avoid or reduce a glare effect, wherein the anti-glare layer (54) is designed to reduce glare caused by light incident obliquely from the side; - a heating layer (55) applied to the carrier screen (51) for the controllable heating of the protective screen (5), - a protective layer (56) which is designed to prevent the adhesion of dirt particles. Protective screen (5) after Claim 1 , wherein the carrier disk (51) is provided with an opaque region by an opaque masking (52), in particular a black print, such that one or more detection windows (53) are formed, wherein the heating layer (55) is in particular applied directly to the opaque masking (52). Protective screen (5) after Claim 2 , wherein the one or more detection windows (53) is/are provided with a color filter. Protective screen (5) after Claim 2 or 3 , wherein at least one of the detection windows (53) has a rectangular cross-section with rounded corners. Protective screen (5) according to one of the Claims 1 until 4 , wherein the anti-glare layer is applied directly to the carrier disc (51) or to the heating layer (55). Protective screen (5) according to one of the Claims 1 until 5 , wherein the protective layer (56) is applied to the anti-glare layer (54). Protective screen (5) according to one of the Claims 1 until 6 , wherein the heating layer (55) is formed with an electrically conductive coating with a negative temperature coefficient, wherein the electrically conductive coating is formed in particular by a semiconductor heating lacquer. Protective screen (5) according to one of the Claims 1 until 7 , wherein the heating layer (55) can be contacted by at least two contact surfaces (57), wherein in particular the contact surfaces (57) are contacted with electrical contact pins (58) which are led out at predetermined positions laterally of the protective pane (5), in particular at positions opposite one another. Protective screen (5) according to one of the Claims 1 until 8 , wherein the protective pane (5) is provided with a seal (8) surrounding an outer edge of the carrier pane (51) and protruding on both sides beyond the main surfaces of the protective pane (5), wherein the seal (8) is in particular formed with a separate sealing part (81, 82) on each of the main surfaces of the protective pane (5). Protective screen (5) according to one of the Claims 1 until 8 , wherein the protective disk (5) is provided with a seal (8) surrounding an outer edge of the carrier disk (51), which is constructed from sealing parts (81, 82) which are each arranged on a main surface of the protective disk (5). Protective screen (5) according to one of the Claims 1 until 10 , wherein the carrier disk (51) is flat or is designed in the shape of a convex lens and has a curved surface. Optoelectronic sensor system (1), in particular a camera system, with a protective screen (5) according to one of the Claims 1 until 9 in the beam path of the sensor system (1). Optoelectronic sensor system (1) according to Claim 12 with an optoelectronic sensor device (2) and a housing (3), wherein the housing (3) has an opening (4) which closes the protective screen (5). Optoelectronic sensor system (1) according to Claim 12 or 13 , wherein an ultrasonic transmitter (6) is provided which engages laterally on the protective screen (5) in order to protect the protective screen (5) from contamination on the surface of the protective screen (5) by subjecting it to an ultrasonic vibration. Optoelectronic sensor system (1) according to one of the Claims 12 until 14 , wherein an electrical heating supply source (7) is provided which is connected to the electrically conductive heating layer (55) of the protective pane (5) in order to enable heating of the protective pane (5) by supplying current.

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