FIELD OF THE INVENTION

The invention relates to optical sensor module, in particular a camera, comprising a heater element.

BACKROUND OF THE INVENTION

From the state of the art there are already cameras known which comprise a heating element. Those heating elements can be used e.g. to defrost or defog a camera lens. The heating element is arranged in the housing and is kept in place by crash rib features. Also, the mounting of the heater in the housing requires an additional step/station in the production line. Additionally, heater clips are needed to connect the heater with the PCB.

One drawback of the current setup is that the power efficiency of the heater is currently low. Another issue is that the heater in the current design is held in place by crash rib features. Because the camera housing is made of aluminum and the heater is realized from plastic material, in time due to aging, vibrations and thermal shocks, the press fit between the two components can get loose. If the heater will get loose, the contact between the heater and PCB can be interrupted, leading to a malfunction for the defrost/defog system and potential PCB damage due to vibrations and scratches, that can lead also to cleanliness impurities on the imager.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an optical sensor module with a heater element which provides a robust fixation of the heater element over lifetime, has a low power consumption, and has low production costs.

This object is advantageously solved by features of independent claim 1. Further embodiments are described in the dependent claims. According to the invention an optical sensor module is provided comprising a lens assembly, a PCB comprising an imager, a housing, and a heater element. Further, the heater element is a PTC heating element arranged above the PCB and around at least a lower part of the lens assembly.

The optical sensor module is preferably a camera, in particular a mono camera or surroundview camera. The PTC element means it has a positive thermal coefficient of resistance. The use of such a PTC element is advantageous since it has reduced power consumption. A PTC heater is self-regulating and therefore no over-temperature protection is necessary. It also provides a wide temperature range and is available for all common voltages (12, 24, 42, 120, 230 and 500V).

Additionally, PTC elements are easy to implement from a components point of view. The heater element is used to defrost or defog the lens.

In a preferred embodiment the heater element is fixed to the PCB. This is advantageous since with the fixation directly on the PCB the heater element can be assembled with other parts on the PCB. Additionally, the fixation of the heater element directly to the PCB is more robust than the fixation with crash ribs on the housing.

In a further preferred embodiment, the heater element is fixed as a surface mounted device SMD, fixed by means of press fit, or fixed with through hole technique to the PCB. A surface mounted device is in particular advantageous since it is directly soldered to the PCB. With all these fixation methods a robust and low-cost fixation on the PCB can be achieved, since no other processes are needed to fix the heater and therefore no additional equipment and production time is needed. The heater is in this case assembled during the SMD process of the PCB.

In a further embodiment the PTC heater element is a ceramic element. A ceramic element is advantageous since it is cheaper than previously used heater solutions. Additionally, the ceramic material has a better efficiency due to the fact that the material is heated uniformly. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in greater detail with reference to exemplary embodiments depicted in the drawings as appended.

The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts.

Fig. 1 a - c each show a schematic view of a heater element according to an embodiment of the invention;

Fig. 2 shows a section view of an optical sensor module according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 a, 1 b and 1 c each show a schematic view of a heater element according to an embodiment of the invention. The heater element 2 is hereby fixed to a PCB 3. On the PCB 3 an imager 4 is also located. In these figures the heater element 2 is fixed as a surface mounted device SMD. As it can be seen in figure 1 a and especially in figure 1 b the heater element 2 is fixed with connecting points 2a (or “legs” of the heating element) to the PCB 3. These connecting points 2a are soldered directly to the PCB 3. As can be seen in figures 1 a and 1 c the PCB 3 also has holes 3a which can be used to fix the PCB 3 to a housing or a respective element of the optical sensor module 1 . The heater element 2 has a circular shape and can therefore be better arranged around the lens assembly 5, in particular the lens barrel, which also has generally a circular shape. This is advantageous since the heater element is used for defrosting or defog purposes and the closer the heater element is to the lens assembly the better the lens can be defrosted/defogged due to less heat loss.

Figure 2 shows a section view of an optical sensor module according to an embodiment of the invention. The optical sensor module 1 comprises a lens assembly 5, a heater element 2 with connecting points 2a, a PCB 3, an imager 4 mounted on the PCB 3 and a housing 6 which covers the imager 4, the heater element 2, the PCB 3 and at least a part of the lens assembly 5. The heater element

2 is in this particular case fixed as a surface mounted device SMD to the PCB 3 and has connecting points/legs 2a soldered to the PCB 3, as already depicted in figures 1 a and 1 b. As can be seen the heater element 2 is located above the PCB 3 and the imager 4 and is arranged around at least a lower part of the lens assembly 5. The lens assembly 5 contains at least one lens or more than one lens and an aperture. Further, the lens barrel of the lens assembly 5 is coated with a non-conductive material. Therefore, if the ceramic material would touch the lens barrel there would not be an issue. The lens assembly 5 is connected to the housing 6. The PCB 3 is also attached to the housing 6. The heater element 3 is only rigidly fixed to the PCB

3 and not connected to the lens assembly 5 or the housing 6.

REFERENCE NUMERALS

1 optical sensor module

2 heater element 2a connecting points/legs

3 PCB (printed circuit board)

3a holes

4 imager

5 lens assembly 5a lower part of the lens assembly

6 housing