Patent Description:
The present inventive technology concerns an optical lens assembly, in particular for outdoor use. Such optical lens assemblies may be used in particular in camera modules, such as vehicle surround cameras and/or webcams. Further, such optical lens assemblies may be used in telescopes, binoculars and/or spectacles. The inventive technology further concerns a camera module, in particular for automotive applications, such as vehicle surround and e-Mirror cameras, as well as a respective camera system.

Optical lens assemblies, for example as part of vehicle cameras, are exposed to all kinds of environmental conditions, such as moisture, humidity, and/or extreme temperatures. In particular fog and/or ice impairs the optical function of such optical lens assemblies. To mitigate the effect of fog and/or frost, it is known to heat the optical lens assembly. Regularly, external heaters, such as heater blankets, are installed next to the optical lens assembly, in particular at least partially surrounding the optical lens assembly. Such external heaters are inefficient and require long heating times, as the complete optical lens assembly has to be heated. Heating devices may also be integrated into the optical lens assembly. For example, heating elements may be arranged on a front surface or a rear surface of a front element of the optical lens assembly. When installed on the front or outer surface of the front element, the heating element is exposed to environmental conditions. When installed on the rear or inner surface of the front element, the heating element impairs the arrangement of further lenses in the so-called lens stacking. In both cases, the heating element intrudes in the optical pathway of the optical lens assembly, impairing the optical properties.

<CIT> discloses an optical device and application thereof. <CIT> discloses an optical device and use thereof. <CIT> discloses a camera module, vehicle camera and monitoring system. <CIT> discloses an optical device with heating element.

Moreover, integrating heating devices in the optical lens assembly, requires to contact the heating devices in the optical lens assembly. Routing and connecting electric wires within the optical lens assembly is complicated. For example, conductor wires may be routed inside the lens mount, requiring the conductors to pass lens elements arranged therein. This may interfere with the arrangement of the lens elements. Moreover, wiring components may be exposed to forces required to hold lens elements in place. In particular in outdoor applications, the optical lens assembly requires waterproofing. Routing the wires around the waterproofing may impair the sealing properties of the optical lens assembly.

It is an object of the present inventive technology to improve an optical lens assembly, in particular to provide an optical lens assembly with efficient and reliable heating without impairing the optical properties and/or sealing of the optical lens arrangement.

This object is achieved by an optical lens assembly according to claim <NUM>. The optical lens assembly comprises a lens mount, a lens arrangement of one or more lens elements inside the lens mount, and a heating element for heating at least one of the one or more lens elements, in particular a front element at an object-side of the lens arrangement. The lens mount, in particular a lens holder thereof, comprises a lens mount wall defining an inner space for accommodating one or more lens elements of the lens arrangement, wherein the heating element is housed within the lens mount wall. The heating element is securely arranged inside the lens mount wall, in particular protected from the environment. The heating element is housed inside the lens mount wall so that it has no direct contact with the one or more lens elements. Advantageously, the heating element is integrated in the optical lens assembly without impairing the positioning and/or insertion of the one or more lens elements inside the lens mount. Moreover, the flexibility with regard to usable lens elements is increased. In particular, the heating element may be preinstalled in the lens mount. Insertion of the one or more lens elements does not require interaction with the heating element, e.g. by connecting the heating element to one or more of the lens elements, in particular the front element. Moreover, the heating element does not impair sealing properties of the optical lens assembly. As a further advantage, the heating element does not impair the optical properties of the lens assembly, in particular does not protrude in the optical path. Particularly advantageous, the heating element is not arranged in the region of or attached to the first (outer) or second (inner) surface of the front element, so that the heating element is neither subject to environmental hazards nor to forces acting on the lens elements. This results in a reliable and stable arrangement of the heating element.

As a further advantage, the heating element does not have any impact on or hinders the application of possible coatings on the first and/or second surface front element. Such coatings may be used for improving scratch resistance, anti-reflection and the like.

In the present context, an optical lens assembly is to be understood as an optical device for imaging an object at the object-side into an image on an image-side, which is opposite to the object-side. Such optical device may also be referred to as objective. In particular, when used in a telescope or binocular, the image may be directly observed by a user. In particular, when used in a camera module, the resulting image is sensed by an image sensor.

The optical lens assembly comprises a lens arrangement, also referred to as lens stack, of one or more elements. The lens arrangement is arranged in a lens mount, holding the lens elements of the lens arrangement in their respective position.

The lens mount may, in particular, comprise a lens holder and a lens cap. For example, the lens cap may be attached to, in particular screwed on, the lens holder, in particular a lens barrel thereof, at the object-side of the lens holder. The lens cap may secure the lens elements arranged inside the lens holder in place.

The lens mount may further comprise one or more spacer components arranged between the lens cap, the lens holder and/or the lens arrangement.

The lens mount may further comprise one or more heat transfer components for transferring heat from the heating element to at least one of the one or more lens elements.

The lens holder may have a lens barrel, in which one or more of the lens elements of the lens arrangement are arranged. The lens holder may additionally comprise a base portion (which may be also referred to as front camera housing) at a side of the lens barrel opposite to the lens cap. The base portion may, in particular, serve for connecting to further components, in particular to further components of a camera module such as a printed circuit board assembly and/or a back cover. The lens holder and the base portion may be configured as a single piece.

The lens mount wall may be a wall of the lens holder, in particular of the lens barrel. In that case, the lens mount wall may also be referred to as lens holder wall or lens barrel wall. The lens mount wall may, additionally or alternatively, comprise a wall of the lens cap and/or a lens retainer. The lens mount wall may in particular comprise any space formed between components of the lens mount, in particular formed between the lens cap and the lens holder.

Housing the heating element within the lens mount wall in particular is to be understood in that the heating element is surrounded by the lens mount wall, in particular by one or more different components of the lens mount. In particular, the heating element is covered by parts and/or components of the lens mount, in particular of the lens holder, in direction towards the inner space, in which the one or more lens elements are arranged, and the outside of the optical lens assembly.

Preferably, the heating element is housed in the wall of the lens holder (lens holder wall), in particular the wall of the lens barrel (lens barrel wall). This allows for a particularly secure positioning of the heating element, in particular without requiring special front elements, e.g. front elements with grooves for receiving the heating element and/or front elements with the heating element embedded therein.

For example, the heating element may be placed in a cavity of the lens mount, in particular the lens holder. For example, the lens mount, in particular the lens holder, may be provided with a cavity. The heating element may be placed inside the cavity and the cavity may be closed. For example, a closure component may be attached to the lens mount, in particular the lens holder. It is also possible that, after insertion of the heating element, the cavity is filled with a material, in particular by moulding. This allows for a particularly high design freedom of the lens mount, in particular the lens holder. The lens holder may be of a different material than the closure component or the filler material.

The lens mount, in particular the lens holder, may, at least partially, be made of metal, in particular aluminium. This allows for a better heat dissipation, in particular of heat generated by electrical components of a camera module, e.g. a printed circuit assembly, in particular an image sensor thereof.

It is also possible that the lens mount, in particular the lens holder, are made from plastic material. Plastic material allows for an easy and cost efficient production with high design freedom. Moreover, plastic material may be used to embed the heating element, in particular via over-moulding.

The heating element may, in particular, comprise a resistive heating element, such as heating wire. The heating element may have a heating wire wrapping around the lateral surface of the front element. Such heating elements are efficient, easily installable as well as reliable.

The heating element is housed inside the lens mount wall so that it has no direct contact with the one or more lens elements. This allows for a particularly low impact of the heating element on the positioning of the lens elements and the sealing of the optical lens assembly. Moreover, the heating element is securely shielded from any forces, which might act on the lens elements, and/or environmental impacts. Preferably, the heating element is positioned closely to the inner wall of the lens mount to permit good heat transfer to the lens element.

For example, the heating element, which is housed within the lens mount wall so that it has no direct contact with the one or more lens elements, may be positioned close to one of the lens elements, in particular the front element, advantageously improving the transfer of heat to the lens element. For example, the heating element may be positioned inside a groove of the lens mount wall, being surrounded by the lens mount wall to at least three sides.

According to a preferred aspect of the inventive technology, the lens arrangement comprises a front element at an object-side of the lens arrangement. The front element comprises a first surface facing the object-side, a second surface opposite to the first surface, and a lateral surface connecting the first surface and the second surface. The heating element is arranged circumferentially along the lateral surface of the front element. This arrangement ensures direct and efficient heating of the front element.

A front element in the sense of the present inventive technology is to be understood as the lens element of the lens arrangement, which faces the object-side. In other words, the front element is the outermost lens of the lens arrangement on the object-side. The front element is the lens element through which light enters the optical lens assembly from the object-side. The front element may have an optical function. It is also possible that the front element may be or comprise a cover glass, in particular a flat cover glass, without optical function. The front element may, in particular, be mounted inside or outside of the lens mount, in particular inside or outside of a lens cap of the lens mount. Preferably, the front element may be arranged at an object-side of a lens holder, in particular a lens barrel. For example, the front element may be secured in place via a lens cap.

The front element comprises the first surface at an object-side. The first surface is the surface facing outwardly from the optical lens assembly. The first surface may also be referred to as the outer surface of the front element. The second surface, opposite to the first surface, faces the inner side of the optical lens assembly, in particular further lens elements of the arrangement. The second surface may also be referred to as inner surface. First and second surface are connected via a lateral surface of the front element. The lateral surface of the front element is the radially outward surface of the front element. It essentially extends along an optical axis of the lens arrangement. The optical axis may also be referred to as the longitudinal axis of the lens arrangement.

An optical material of the lens elements, in particular of the front element may, e.g., be glass or a transparent polymer, such as acrylic glass.

According to a preferred aspect of the inventive technology, the heating element is embedded in the lens mount wall, in particular the lens holder wall, preferably the lens barrel wall. Being embedded within the lens mount wall, in particular the lens barrel wall is in particular to be understood as being surrounded by the lens mount wall, in particular the lens barrel wall to all sides.

For example, the heating element may be overmoulded by the lens mount wall, e.g. during injection moulding of the lens mount. This ensures a particularly secure arrangement of the heating element. The heating element is reliably protected from environmental influences. Further, the arrangement of the heating element does not compromise sealing, in particular waterproofing, of the lens mount.

It is also possible to use multiple-component injection moulding, in particular two-component injection moulding. This way, different materials can be combined in the lens mount. In particular, different plastic materials may be used. For example, a part covering the heating element may be formed from plastic with a particularly high thermal conductivity.

Additionally to the heating element, also wiring for supplying the heating element with electrical energy may be routed, in particular embedded, within the lens mount wall, in particular within the lens holder wall. This way, a simple and reliable electrical connection is established. It is also possible, that the heating element comprises a secondary coil of an induction coil arrangement, which is housed, in particular embedded, within the lens mount wall. This way, the embedded heating element can be supplied with energy without requiring mechanical contacts.

For example, the heating element may comprise a secondary coil of a conduction coil arrangement for supplying the heating element with electrical energy. This simplifies the electric energy supply. The heating element can be easily housed, in particular embedded, within the lens mount wall without requiring physical connections for energy supply. The heating element can be completely embedded, in particular hermetically sealed, within the lens mount wall.

A primary coil of the induction coil arrangement may be incorporated in the optical lens assembly, for example in the lens mount. For example, the primary coil of the heating coil arrangement may be housed, in particular embedded, in the lens cap and/or the lens holder. It is also possible that a primary coil of the induction coil arrangement is not part of the optical lens assembly. For example, the primary coil may be part of further components of a camera module. A primary coil of the induction coil arrangement may also be part of an enclosure, for example camera enclosure, in which the optical lens assembly is arranged during usage.

According to a preferred aspect of the inventive technology, the lens mount comprises a lens holder and a lens cap, wherein the lens cap is attached to the lens holder at an object side of the optical lens assembly. The heating element is arranged in between the lens cap and the lens holder, in particular within an annular space formed between the lens cap and the lens holder. Arranging the heating element between the lens cap and the lens holder allows for a particularly easy assembly of the optical lens arrangement, ensuring that the heating element is safely housed within the lens mount wall. For example, it is not necessary to insert the heating element within the lens holder wall, in particular the wall of a lens barrel, e.g. via injection moulding. This increases the flexibility in the choice of the lens holder, in particular the material, of which the lens holder is made. Further, the heating element can be easily replaced by removing the cap, increasing the maintainability of the optical lens assembly. It is also possible that the camera module is hermetically sealed, e.g. by glue, to avoid moister ingress.

According to a preferred aspect of the inventive technology, the lens mount comprises a heat transfer component arranged between the heating element and at least one or more lens elements, in particular a front element, of the lens arrangement. A heat transfer component ensures an efficient heat transfer from the heating element to the lens element to be heated.

The heat transfer component may be part of the lens mount wall, which houses the heating element. The heat transfer component may be made of metal, in particular aluminium and/or brass. The heat transfer component may be a separate part of the lens mount and/or integrated in other components of the lens mount, in particular in the lens holder. The heat transfer component may, e.g. be part of a lens holder wall, in particular being configured in one piece with other parts of the lens mount wall. For example, the heat transfer component may be a protrusion of the lens mount wall protruding, in particular in direction of the optical axis, between the heating element and the lens element, in particular the front element.

For example, it is possible to include the heat transfer component in the lens holder by multiple-component injection moulding of the lens holder. For example, the heat transfer component may be moulded from a plastic material, which has a higher thermal conductivity than plastic material used for moulding other parts of the lens holder.

According to a preferred aspect of the inventive technology, the heat transfer component is a spacer ring accommodating at least one of the lens elements, in particular, the front element.

Using a spacer ring (inductive or non-inductive) as heat transfer element is particularly suitable. Different functionalities can be combined in the spacer ring, namely the heat transfer as well as a precisely defined arrangement of the lens element. The spacer ring is, in particular, part of the lens mount for mounting the one or more lens elements.

According to a preferred aspect of the inventive technology, the heat transfer component contacts at least one or more of the lens elements, in particular the front element, at least circumferentially along a lateral surface of the front element. Supplying the heat to the lens element via the lateral surface has proven particularly advantageous. The heat can be efficiently supplied to the lens element, in particular the front element, without impairing optical properties of the lens element. The lens element can be heated in an efficient and homogenous way.

According to a preferred aspect of the inventive technology, the heat transfer component contacts at least one or more of the lens elements, in particular the front element, on one or preferably on at least two surfaces thereof. Preferably, the heat transfer component contacts at least one lens element circumferentially along the lateral side and at least on one of the first and the second surface, preferably on the second surface. This way, heat transfer to the lens element, in particular the front element, is particularly efficient and homogenous. For example, the heat transfer component may be configured as a spacer ring, which accommodates the lens element to be heated. Contacting the lens element on at least two surfaces results in a particularly precise and stable positioning of the lens element via the spacer ring.

According to a preferred aspect of the inventive technology, the lens mount comprises a thermal insulator for thermal shielding of parts of the lens mount, in particular the lens holder, from the heating element and/or a heat transfer component, which is arranged between the heating element and at least one or more of the lens elements, in particular the front element. The thermal insulator ensures that heat produced by the heating element cannot damage other parts of the lens mount, in particular parts made of plastic material. Moreover, the thermal insulator ensures that the produced heat is efficiently transferred to at least one lens element to be heated and not to other parts of the optical lens arrangement, which do not require heating. For example, the thermal insulator may particularly advantageously be placed between a heat transfer component and other parts of a lens mount, which may be build from metal. This way, heat flux through the material of the lens mount away from the lens element to be heated is reduced, in particular, avoided.

According to a preferred aspect of the inventive technology, the optical lens assembly comprises wiring for supplying the heating element with electrical energy. Further components, in particular an enclosure, which comprise the wiring are not necessary.

According to a preferred aspect of the inventive technology, the wiring is housed inside the lens mount, in particular within a lens mount wall. For example, the wiring may be routed within a lens holder wall.

According to a preferred aspect of the inventive technology, the wiring is embedded within a lens mount wall, in particular inside a lens holder wall. For example, the wiring may be inserted through a cavity or embedded by over-moulding the wiring during manufacturing the lens mount, e.g. via injection moulding of the lens mount and/or parts thereof, for example the lens holder. The wiring is protected from environmental influences and securely held in position.

Preferably, the heating element and the wiring may be inserted or embedded inside the lens mount wall, in particular the lens holder wall, by over-moulding the heating element and the wiring, when forming the lens mount, in particular the lens holder.

Particularly preferable, the wiring may be routed within the lens mount wall, in particular a lens holder wall, to an end face thereof, which opposes the object-side of the optical lens assembly. In particular, the wiring may be routed within the lens mount wall along essentially the entire length of the lens mount, in the direction of an optical axis of the lens arrangement, without impairing the lens arrangement. As such, the wiring can be easily routed to the back side of the optical lens assembly. This is in particular advantageous, if the wiring shall exit the optical lens assembly at the respective end face. In particular, in camera applications, the wiring can be connected to a printed circuit board assembly of a camera module. This allows to supply electrical energy to the heating device via the printed circuit board assembly of the camera module.

A wiring of the heating device for supplying electrical energy to the heating element may be routed, in particular housed, within the lens mount wall. Routing the wiring within the lens mount wall has the advantage that routing the wiring does not interfere with the lens elements arranged within the inner space of the lens mount. The wiring is protected from environmental conditions and from forces, which may be applied for holding the lens elements in place.

The lens mount may comprise a lens cap and a lens holder, the latter in particular being or comprising a lens barrel. Particularly preferably, the lens mount wall is a lens holder wall, in particular a lens barrel wall. Advantageously, the wiring is routed, in particular housed, within a lens holder wall.

According to a preferred aspect of the inventive technology, the wiring is recessed inside a groove of the lens mount wall, in particular, inside a groove of a lens holder wall. Preferably, the lens mount wall, in particular, the lens holder wall, is manufactured with a respective groove for receiving the wiring. The wiring can then be pre-installed before the assembly of the optical lens assembly. Preferably, the assembly of the optical lens assembly is unaffected by the pre-installed wiring, so that, e.g. existing processes can be used for the assembly.

According to a preferred aspect of the inventive technology, the wiring is embedded within the lens mount wall, in particular, within the lens holder wall. For example, the wiring may be embedded during the manufacturing process of the lens mount, in particular the lens holder. For example, the wiring may be embedded by over-moulding the wiring during manufacturing the lens mount, e.g. via injection moulding of the lens mount and/or parts thereof, for example the lens holder. This ensures a particularly secure protection of the wiring. The wiring can be provided as an integral part together with the lens mount, in particular the lens holder, e.g. a lens barrel thereof.

According to a preferred aspect of the inventive technology, the wiring is routed within the lens mount wall, in particular a lens holder wall, to an end face thereof, which opposes the object-side of the optical lens assembly. In particular, the wiring may be routed within the lens mount wall along essentially the entire length of the lens mount, in direction of an optical axis of the lens arrangement, without impairing the lens arrangement. As such, the wiring can be easily routed to a back side of the optical lens assembly. This is in particular advantageous, if the wiring shall exit the optical lens assembly at the respective end face. In particular, in camera applications, the wiring can be connected to a printed circuit board assembly of a camera module. This allows to supply electrical energy to the heating device via the printed circuit board assembly of the camera module.

According to a preferred aspect of the inventive technology, the lens cap is attached to the lens holder, in particular to a lens barrel thereof, in a sealing manner, in particular via one or more sealing elements. For example, the lens cap may be attached in a sealing manner, using at least one O-ring. This way, the optical lens assembly is particularly suitable for outdoor use, in particular in wet conditions. Routing the wiring out of the lens cap or within a lens mount wall, does not impair the sealing achieved by at least one sealing element.

According to a preferred aspect of the inventive technology, the wiring is routed radially out of the lens holder, in particular via a through barrel connector. For example, the wiring may be radially routed out of a lens holder, in particular out of the lens barrel. For example, the wiring may be routed within the lens holder wall in the direction of an optical axis of the lens arrangement from the position of the heating element at an object-side of the lens mount to an exit position away from the object-side. At the exit position, the wiring may be routed radially out of the lens mount, in particular, of the lens holder. Particularly advantageously, the wiring is routed out via a through barrel connector, allowing for an easy connection of external components to the through barrel connector.

It is a further object of the inventive technology to improve a camera module, in particular for automotive applications.

This object is achieved by a camera module according to claim <NUM>. The camera module comprises an optical lens assembly as described above. The advantages and preferable features of the camera module coincide with those of the optical lens assembly. The camera module may incorporate any of the above-described optional features.

The camera module may, additionally to the optical lens assembly, comprise a printed circuit board assembly comprising an image sensor for sensing an image generated with help of the optical lens assembly. Further, the camera module may comprise a back cover for covering the printed circuit board assembly at a side opposite of the optical lens assembly. Particularly preferably, the lens mount of the optical lens assembly comprises a lens holder having a lens barrel and a base portion, where the base portion covers the printed circuit board assembly at an ob-ject-side thereof.

According to a preferred aspect of the inventive technology, the camera module comprises a printed circuit board assembly with an image sensor, wherein the heating element is connected to the printed circuit board assembly for supplying electrical energy to the heating element. This allows for a simple connection of the camera module, in particular via a single connector, e.g. via a FAKRA connector. For example, connection can be established by wiring, which is routed within the lens mount wall, in particular the lens barrel wall.

It is a further object of the present inventive technology to improve a camera system, in particular for automotive applications.

This is achieved by a camera system according to claim <NUM>. The camera system comprises the above-described camera module as well as a camera enclosure, to which the camera module is attached. A camera enclosure may be realized by parts of a vehicle. For example, the camera enclosure may be installed behind a wing front panel. In such camera systems, the camera module may, for example, be used as a vehicle surround camera.

According to a preferred aspect of the inventive technology, the camera module is detachably attached to the camera enclosure, in particular by a snap-fit connection. This allows easy installation, replacement and maintenance of the camera module.

According to a preferred aspect of the inventive technology, the camera enclosure comprises enclosure wirings supplying electrical energy to the heating element of the optical lens assembly. This simplifies the electrical connection of the heating element. In particular, complicated wirings do not have to be integrated into the camera module. Particularly preferably, the camera enclosure may comprise a primary coil of an induction coil arrangement interacting with a secondary coil comprised by the heating element.

The present disclosure also relates to further aspects of optical lens assemblies, camera modules, and/or front elements for lens assemblies, which alone or in combination with other aspects may be an independent aspect of the present invention.

According to an aspect of the disclosed technology, which is not part of the present invention, the heating element may be attached to or may be part of one of the lens elements, in particular the front element.

In a disclosed example, which is not part of the present invention, the heating element may comprise transparent conductors, such as conductive coatings, preferably a conductive coating of PEDOT. Such conductive coatings may cover at least parts the lateral surface. It is also possible that the conductive coating covers least parts of the first and/or second surface. Preferably, the heating only comprises a heating element arranged circumferentially along the lateral surface of the front element. Particularly preferably, the heating element is realized by a circumferentially arranged heating resistor, in particular a heating wire wrapped circumferentially along the lateral surface. Advantageously, the heating element is neither arranged on the first nor on the second surface but only circumferentially along the lateral surface.

According to an aspect of the disclosed technology, which is not part of the present invention, the heating element is recessed inwardly with respect to a radial extension of the lateral surface. This improves the heat transfer from the heating element to the front element, in particular to segments thereof close to the optical axis. Further, recessing the heating element stabilizes the arrangement and improves its protection by the front element.

According to an aspect of the disclosed technology, which is not part of the present invention, the heating element is placed inside a groove formed circumferentially along the lateral surface. This allows for a particularly reliable arrangement of the heating element. The heating element is recessed inside the groove and held in place with regard to its radial and axial position circumferentially along the lateral surface.

According to an aspect of the disclosed technology, which is not part of the present invention, the heating element is at least partially embedded in an optical material of the front element. For example, a groove, in which the heating element is recessed, may be closed by optical material of the heating element. This further improves heat transfer and stability of the heating element. For example, the heating element may be embedded in the optical material but for lead outs needed to connect the heating element to electrical wiring. Further, openings in the embedding may be used for heat dissipation.

According to an aspect of the disclosed technology, which is not part of the present invention the heating element is completely embedded in an optical material of the front element. The heating element is securely positioned and protected inside the front element. For example, the heating element may be a secondary coil of an induction coil arrangement. This way, electric energy needed for operating the heating element may be provided without leads or wiring leading out of the front element. A primary coil of the induction coil arrangement may be arranged in a lens cap or even outside of the optical lens assembly. This further simplifies the wiring needed for connecting the optical lens assembly to the electrical energy source.

According to an aspect of the disclosed technology, which is not part of the present invention, a front element for an optical lens assembly comprises a first surface facing an object-side, a second surface opposite to the first surface, a lateral surface connecting the first surface and the second surface, and a heating element. The heating element is arranged circumferentially along the lateral surface and recessed inwardly with respect to a radial extension of the lateral surface.

The front element can be efficiently heated by the integrated heating element. The heating element is securely placed along the lateral surface of the front element, without impairing the optical properties thereof. The front element may comprise any of the optional features described with regard to the front element above. In particular, the front element may comprise a groove formed circumferentially along the lateral surface, in which the heating element is placed. The heating element may be at least partially, in particular completely, embedded in an optical material of the front element.

According to an aspect of the disclosed technology, which is not part of the present invention, an optical lens element, in particular a front element, for an optical lens assembly may comprise a heating element having a transparent conductor on at least one of the first and/or the second surface. In particular, the front element may comprise a transparent conductive coating of PEDOT. The PEDOT coating may particularly preferably be applied via inkjet printing. This allows to precisely apply the transparent conductive coating. It is additionally or alternatively possible to apply transparent conductors to at least parts of the first and/or second surface of the front element in form of a metal mesh. Using a PEDOT coating and/or a metal mesh as a transparent conductor on at least parts of the first and/or second surface of the front element is an independent aspect of the inventive technology described herein.

The disclosed technology also refers to an optical lens assembly having a lens mount, one or more lens elements arranged inside the lens mount and a heating device having a heating element for heating at least one of the one or more lens elements, wherein the heating element is arranged inside the lens mount. The lens mount comprises a lens holder and a lens cap, which is attached to the lens holder at an object-side of the optical lens assembly. A wiring of the heating device for supplying electrical energy to the heating element exits the lens mount through the lens cap. Routing the wiring out of the lens cap has the advantage that the wiring has not to be routed inside the lens mount, in particular inside the lens holder. As such, the wiring does not interfere with the one or more lens elements. Further, a sealing of the optical lens assembly is not compromised by the wiring. Particularly advantageously, the sealing can easily be achieved between the lens cap and the lens holder without being affected by the wiring. The wiring exiting out of the lens cap does not require a separate sealing. The resulting electrical connection is simple to establish and reliable. The manufacturing process is simplified, reducing the manufacturing costs. Preferably, the wiring may exit the lens mount through an opening in the lens cap, in particular through an opening on a lateral side of the lens cap. The opening may but does not have to comprise a sealing or waterproofing, in particular when the heating element is arranged inside the lens cap.

Further details, features and advantages of the inventive technology are obtained from the description of exemplary embodiments with reference to the figures, in which:.

Corresponding parts are identified with the same reference numbers in the respective figures and embodiments. Parts of different embodiments, which are functionally similar, but structurally differ, bear the same reference number with small letters "a", "b",. appended thereto.

With regard to <FIG>, a first embodiment of a camera module <NUM>, which is not according to the present invention, is described. The camera module <NUM> may be used in automotive applications, e.g. as rear view camera or vehicle surround camera. The camera module <NUM> comprises an optical lens assembly <NUM>, a printed circuit board (PCB) assembly <NUM> and a back cover <NUM>. The printed circuit board assembly <NUM> comprises an image sensor <NUM> for sensing an image of an object imaged via the optical lens assembly <NUM>.

The optical lens assembly <NUM> comprises a lens mount <NUM> having a lens holder <NUM> and a lens cap <NUM>. The lens holder <NUM> may comprise a base portion <NUM> and a lens barrel <NUM>. A lens arrangement <NUM> is arranged inside the lens mount <NUM>. The lens arrangement <NUM> comprises several lens elements <NUM> being arranged within the lens holder <NUM>, in particular its lens barrel <NUM>. The lens arrangement <NUM> further comprises a front element <NUM>, which is arranged at the object-side of the camera module <NUM>. The object-side is the side where an object to be imaged by the optical lens assembly is placed. With regard to <FIG>, the object-side is on the left side of the optical lens assembly <NUM>. In other words, the front element <NUM> is the outermost lens element of the lens arrangement <NUM>. The front element <NUM> terminates the lens arrangement <NUM> to the outer surroundings. The front element <NUM> is subject to influences from the environment, in particular weather conditions, such as frost, rain and/or fog.

The front element <NUM> is arranged at the object-side end of the lens holder <NUM>. In the shown embodiment, the front element <NUM> is placed between the lens cap <NUM> and the lens holder <NUM>. The lens cap <NUM> is attached to the lens holder <NUM> at the object-side of the lens assembly <NUM>. The front element <NUM> is held in place by the lens cap <NUM>. The lens cap <NUM> comprises projections <NUM> interacting with a holding portion <NUM> formed on front element <NUM>. The holding portion <NUM> is formed as a radially protruding portion of the front element <NUM>.

The lens cap <NUM> is attached to the lens holder <NUM> in a sealing manner using a circumferential sealing element <NUM> in form of an O-ring. This ensures that no humidity or other pollution can enter the lens holder <NUM> and compromise the performance of the camera module <NUM>, in particular of the optical lens assembly <NUM>.

To reduce environmental effects on the front element <NUM>, such as frosting and/or fogging, the optical lens assembly <NUM> comprises a heating device <NUM>. The heating device <NUM> comprises a heating element <NUM> for heating the front element <NUM>. In the shown embodiment, he heating element <NUM> is integrated in the front element <NUM>. The heating device <NUM> further comprises a wiring <NUM> for supplying the heating element <NUM> with electrical energy.

As can be seen in particular from <FIG>, the front element <NUM> comprises a first surface <NUM>, facing the object-side of the lens arrangement <NUM>. The first surface <NUM> is an outer surface of the front element <NUM>. The front element further comprises a second surface <NUM> opposite to the first surface <NUM>. The second surface <NUM> faces the further lens elements <NUM> of the lens arrangement <NUM> and forms an inner surface of the front element <NUM>. The first surface <NUM> and the second surface <NUM> are connected by a lateral surface <NUM>. The lateral surface <NUM> essentially extends along an optical axis L of the lens arrangement <NUM> (cf.

The heating element <NUM> is arranged circumferentially along the lateral surface <NUM>. The heating element <NUM> is recessed inwardly with respect to a radial extension of the lateral surface <NUM>. In the lateral surface <NUM>, a groove <NUM> is formed, in which the heating element <NUM> is received. The heating element <NUM> is protected within the groove <NUM>. In particular, the heating element <NUM> is not affected by force being applied via the lens cap <NUM> and/or further lens elements <NUM>. In particular, the heating element <NUM> is not affected by relative movement of the front element <NUM> and the lens cap <NUM>. Moreover, the heating element <NUM> is not exposed to environmental impacts. Being arranged circumferentially along the lateral surface <NUM>, the heating element <NUM> is not protruding in the optical pathway through front element <NUM>. As such, the heating element <NUM> directly heats the front element <NUM> without influencing its optical properties.

The arrangement of the heating element <NUM> further has the advantage that the heating element <NUM> does not interact or compromise any coatings of the front element <NUM>, in particular on its first side <NUM>. As such, scratch resistibility and other properties, which may be achieved by such coatings, may be improved.

In the shown embodiment, the heating element <NUM> comprises a heating wire <NUM> being wrapped around the lateral surface <NUM> within the groove <NUM>. Lead outs <NUM> of the heating wire <NUM> can connect to the wiring <NUM> for supplying the heating wire <NUM> with electrical energy.

The wiring <NUM> may comprise a lead <NUM> being routed out of the lens cap <NUM> and connected to a connector <NUM>. The lead <NUM> may comprise or be formed by a flextail lead. The lead <NUM> is routed out of the lens cap <NUM> via an opening <NUM> at a lateral surface of the lens cap <NUM>. This way, the routing out of the lead <NUM> does not compromise the sealing attachment of the lens cap <NUM> to the lens holder <NUM>. The routing of the wiring <NUM>, in particular the lead <NUM>, is simplified. A particular advantage lies in that the opening <NUM> does not have to be waterproof. Waterproofing can be simply done by the sealing element <NUM> between the lens cap <NUM> and the lens holder <NUM>.

With regard to <FIG>, a further embodiment of a camera module 1a, which is not part of the present invention, is described. Camera module 1a only differs from the embodiment described with regard to <FIG> in the wiring 19a. The wiring 19a is formed by pigtail leads <NUM>.

With regard to <FIG>, a further embodiment of an optical lens assembly 2b, which is not part of the present invention, is described. The optical lens assembly 2b may, for example, be used in a camera module as that shown in previous figures. The lens mount 6b comprises a lens cap 8b and a lens holder 7b attached to each other in a sealing manner to the lens holder 7b via the sealing element <NUM>. The lens mount houses the lens arrangement <NUM> with several lens elements <NUM> and a front element 13b. A heating element 18b is circumferentially arranged around a lateral surface 22b of the front element <NUM> in a region of the holding portion <NUM>. The heating element 18b comprises a compressable conductor, which is quenched between the projections <NUM> of the lens cap 8b and the holding portion <NUM>. The heating element 18b is routed out of the lens cap 8b through an opening 27b. The opening 27b may be, but does not need to be waterproof. The heating element 18b connects to a wiring 19b comprising a waterproof flat-blade connector <NUM>.

With regard to <FIG>, an embodiment of a camera system <NUM> is described. The camera system <NUM> comprises a camera module 1c and a camera enclosure <NUM>. The camera enclosure <NUM> comprises holding means <NUM> for holding the camera module 1c. In the shown embodiment, the holding means <NUM> comprise snap-fit protrusions <NUM> for releasably connecting to snap-fit indentions <NUM> of the camera module 1c. The camera system <NUM> may, for example, be arranged behind a wing front panel <NUM> of a vehicle.

The camera module 1c may, in particular, correspond to the camera modules described with regard to preceding embodiments, which are not part of the present invention. For example, the optical lens assembly 2c may correspond to the optical lens assembly described with reference to <FIG>.

Wiring 19c of a heating device of the camera module 1c connects to enclosure wiring <NUM> of the camera enclosure <NUM>. This leads to a particularly easy connectable and reliable electrical connection. In the shown embodiment, wiring 19c may, e.g., comprise a flat-blade connector 29c for connecting to the enclosure wiring <NUM>.

With regard to <FIG>, a further embodiment of a camera system 30d is described. Camera system 30d differs from the camera system <NUM> of <FIG> in that the holding means 32d leave more radial space around the optical lens assembly to for accommodating the flat-blade connector 29c which connects to the enclosure wire 36d.

With regard to <FIG>, a further embodiment of a camera system 30e is described. The camera system 30e comprises a camera module 1e and a camera enclosure 31e. The connection to the enclosure wiring 36e is achieved via a pad connector <NUM> formed on a lateral surface portion of the lens cap 8e. This facilitates electrical connection, when the camera module 1e is attached to the camera enclosure 31e.

With regard to <FIG>, a further embodiment of a front element 13f, which is not part of the present invention, is described. The front element 13f only differs over the front element <NUM> in that the heating wire <NUM> is embedded in optical material of the front element 13f. Only the lead outs <NUM> of the heating wire <NUM> extend out of the optical material of the front element 13f. The embedding may, for example, by achieved by at least partially closing or filling a groove, in which the heating element <NUM> is positioned. This improves the protection of the heating element <NUM>, in particular the heating wire <NUM>.

With regard to <FIG>, a further embodiment of a front element <NUM>, which is not part of the present invention, is described. Front element <NUM> only differs over the heating element <NUM> described with respect to <FIG> in the heating element <NUM>. The heating element <NUM> does not comprise lead outs for electrically connecting to further wiring. Instead, the heating wire <NUM> is short-circuited to form a closed coil <NUM>. The closed coil <NUM> serves as a secondary coil in an induction coil arrangement for inducing electric current in the heating wire <NUM>. As such, a mechanical connection is not required for supplying electrical energy to the heating wire <NUM>. This facilitates the arrangement and improves the reliability of the heating element <NUM>. In other embodiments, the heating element <NUM> may be completely embedded in the optical material of the front element (such as e.g. shown with reference <FIG>). In such a case, lead outs exiting the optical material are not required, as electrical energy can be supplied via induction.

With regard to <FIG>, a further embodiment of an optical lens assembly <NUM>, which is not part of the present invention, is described. The front element <NUM> comprises a heating element <NUM> in form of a completely embedded secondary coil <NUM>. In the lens cap <NUM>, a primary coil <NUM> is housed for inducing current in the secondary coil <NUM> of the heating element <NUM>. The secondary coil <NUM> is supplied with electrical energy via wiring <NUM>, which is let out the lens cap <NUM>.

The embodiment of <FIG> shows an exemplary heating coil arrangement comprising the primary coil <NUM> and the secondary coil <NUM>. In the shown embodiment, the primary coil <NUM> is housed in the lens cap <NUM>. In other embodiments, the primary coil may be embedded in a lens cap wall of the lens cap. It is also possible to include the primary coil in other parts of the optical lens assembly, e.g. in a lens holder, in particular in a lens barrel. In yet other embodiments, the primary coil may be realized outside of the optical lens assembly, in particular outside of the camera module. For example, the primary coil may be part of a camera enclosure.

With regard to <FIG>, a further embodiment of a camera system 30i is described. The camera system 30i comprises a camera module 1i and a camera enclosure 31i. In <FIG>, the camera module 1i is shown before being attached to the camera enclosure 31i. For attaching the camera module 1i, the camera module is inserted in the camera enclosure 31i in a direction indicated by arrows A in <FIG>. Upon insertion, the snap-fit protrusions <NUM> engage the snap-fit indentions <NUM>. <FIG> shows the camera system 30i in its assembled form, i.e. with the camera module 1i attached to the camera enclosure 31i.

In <FIG>, the camera system 30i is shown partially cut away for highlighting further details of the camera enclosure 31i and the camera module 1i. The camera enclosure 31i is arranged behind a wing front panel <NUM> of a car. The wing front panel <NUM> comprises a cut out <NUM> behind which the front element 13i is arranged when the camera module 1i is attached to the camera enclosure 31i. For better sealing, a sealing element <NUM> in form of an o-ring is arranged around the cut out <NUM>.

The camera enclosure 31i comprises enclosure wiring 36i comprising leads <NUM>, a connector <NUM> and a primary coil 41i. The primary coil <NUM> is embedded within the camera enclosure 31i. The primary coil 41i interacts with a secondary coil 40i forming induction coil arrangement. The secondary coil 30i forms the heating element 18i of the optical lens assembly 2i of the camera module 1i. As such, the camera module 1i, in particular its optical lens assembly, does not require any wiring for supplying electrical energy to the heating element 18i. The heating element 18i may, for example, be housed in the lens cap, in particular within a lens cap wall.

In <FIG>, a further embodiment of an optical lens assembly 2j for a camera module is shown. The optical lens assembly 2j comprises a heating device 17j with heating element 18j and wiring 19j. Wiring 19j serves for supplying electrical energy to the heating element 18j. The heating element 18j and the wiring 19j are embedded in a lens holder wall <NUM> of the lens holder 7j, in particular of the lens barrel 10j. This way, the heating element 18j and the wiring 19j are securely positioned within the lens holder 7j. For example, the lens holder 7j may be formed by injection moulding, thereby over-moulding the heating element 18j and the wiring 19j. It is also possible to insert the heating element 18j and/or the wiring 19j within a cavity of the lens holder 7j.

The wiring 19j is routed through the lens holder 17j to its end face, which opposes the object-side of the lens arrangement 11j. Doing so allows connecting the wiring 19j to a printed circuit board of a printed circuit board assembly of a camera module. External connections are not required.

In the shown embodiment, the heating element 18j is embedded in the lens holder wall <NUM>. In other embodiments, a primary coil of an induction coil arrangement may be embedded in the lens holder wall. A secondary coil of the induction coil arrangement, which is comprised by or forms the heating element, may be arranged circumferentially around the front element.

With regard to <FIG>, a further embodiment of a camera module <NUM> is described. The camera module <NUM> comprises a lens holder <NUM> with a lens barrel <NUM>. For leading out wirings of a heating device of the optical lens assembly <NUM>, a through barrel connector <NUM> is provided. The through barrel connector <NUM> may serve as a connector for connecting further wirings, for example enclosure wirings of a camera enclosure. Through barrel connector <NUM> may, for example, connect to wirings being embedded in a lens holder wall <NUM> of the lens holder <NUM>. For example, the entire heating device, in particular the heating element and the wiring, may be embedded in the lens holder wall <NUM> and connect to the through barrel connector <NUM>.

With regard to <FIG>, a further embodiment of a front element <NUM>, which is not part of the present invention, is described. The front element <NUM> comprises a heating element <NUM> which is formed as a transparent conductor on the first surface <NUM> facing the object-side. The transparent coating may be formed by PEDOT, which has superior optical and electrical properties with regard to ITO, commonly used for conductive coatings. Particularly preferable, the PEDOT coating may be applied using inkjet-printing of PEDOT on the first surface <NUM> of the front element <NUM>. The conductive coating may be applied alternatively or additionally to a heating wire of a heating element arranged circumferentially along the lateral surface <NUM> of the front element <NUM>.

The front element <NUM> may be combined with any of the above shown camera modules. Particularly preferable, front element <NUM> may be combined with wiring routed out of the lens cap. This is particularly advantageous, as the coating <NUM> is arranged on the object-side of the front element <NUM>, avoiding complicated routings around the front element <NUM>.

Instead of coatings with PEDOT, other transparent conductors may be used. For example, transparent conductors made from metal mesh may be used.

With regard to <FIG>, a further embodiment of a front element <NUM>, which is not part of the present invention, is described. The front element <NUM> differs over the front element <NUM> of <FIG> only in that the conductive coating is not applied over the entire first surface <NUM> of the front element <NUM>, but only in a ring-shaped manner, leaving the middle part of the first surface <NUM> free, thereby not interfering with the optical path which is most relevant for imaging.

In <FIG>, a further embodiment of the camera module 1n is shown. The camera module comprises an optical lens assembly 2n, which is connected via the lens holder 7n to the back cover <NUM>.

Lens mount 6n comprises the lens holder 7n and lens cap 8n, which is attached to the lens holder 7n. The heating element 18n of the heating device 17n is housed within a wall of the lens mount 6n. In the shown embodiment, the heating element 18n is arranged within an annular space <NUM>, formed between the lens cap 8n and the lens holder 7n. Heating element 18n is not in direct contact with a front element 13n of the lens arrangement 11n.

A heat transfer component <NUM> is arranged between heating element 18n and a lateral surface of the front element 13n for conducting heat from the heating element 18n to the front element 13n. Heat transfer component <NUM> is a metallic ring, e.g. made of aluminium and/or brass, surrounding the front element 13n along its lateral surface.

Wiring 19n is routed within the lens holder wall 50n to an end face <NUM> of the lens mount wall <NUM>, which opposed the object side of the optical lens assembly 2n. Wiring 19n exits the lens mount wall 50n at the end face <NUM> and connects to the printed circuit board assembly <NUM>, which carries the image sensor <NUM>. Thus, connecting the camera module 1n to further circuitry can be done via a single connector <NUM>. Connector <NUM> serves for data exchange, in particular for image data exchange, and for supplying electrical energy to the camera module, in particular to the heating device 17n and other components of the printed circuit board assembly <NUM>, e.g. the image sensor <NUM>. Connector <NUM> may, e.g., be a FAKRA connector.

In the shown embodiment, wiring 19n is routed within a canal <NUM> formed in the lens holder wall 50n. Canal <NUM> may be pre-formed in the lens holder wall 50n and the wirings 19n can be inserted in the pre-formed canal <NUM>. For example, lens holder 7n may be formed of a metal, in particular aluminium, which improves heat dissipation of heat generated by the printed circuit board assembly <NUM>, in particular the image sensor <NUM>.

It is also possible, that the lens holder 7n is formed of a plastic material. In this case, it is in particular possible, to embed the wiring 19n within the lens holder wall 50n, e.g. by over-moulding the wiring 19n during injection moulding of the lens holder 7n.

A thermal insulator <NUM> is arranged between the lens holder 7n and the heat transfer component <NUM>. This reduces heat dissipation of heat generated via the heating element 18n to other parts of the lens mount 7n. The heat is efficiently transferred to the front element 13n. For example, if the lens holder 7n is made of metal, in particular aluminium, heat would otherwise be dissipated to other parts of the lens holder 7n. In case the lens holder 7n is made of plastic material, damaging the plastic material by heat of the heating element is avoided.

Heat transfer component <NUM> and thermal insulator <NUM> are part of the lens mount <NUM>. The heating element 18n is housed between the lens cap 8n, the lens holder 7n, the heat transfer component <NUM> and the thermal insulator <NUM>.

The heat transfer component <NUM> and thermal insulator <NUM> may be pre-arranged on the lens holder 7n, in particular in a formfitting manner. In the shown embodiment, thermal insulator <NUM> is placed within a groove at a front face of the lens mount 7n and heat transfer component <NUM> has a respective projection engaging with the thermal insulator <NUM> being placed in the groove.

Since heating element 18n is securely housed within the lens mount wall, in particular within the annular space <NUM>, heating element <NUM> is securely protected from environmental influences. Further, heating element <NUM> can be easily connected to wiring 19n, without impairing sealing of the optical lens assembly 2n. Particularly preferable, the positioning and arrangement of the lens elements <NUM> within the lens mount 7n is not impaired by the heating device 17n, in particular by its heating element 18n. Advantageously, front element 13n can be placed in the lens mount without requiring to connect the heating element 18n to it.

A sealing element 16n in form of an O-ring is positioned between the lens cap 8n and the front element 13n.

The lens cap 8n comprises a sealing member 43n at its outer circumference. Sealing member 43n provides sealing, when the camera module 1n is inserted in a camera enclosure, e.g. in an automotive application.

In <FIG>, a further embodiment of a camera module 1o is shown. Camera module 1o is similar to camera module 1n, so that corresponding components are not discussed in detail again.

Camera module 1o differs from camera module 1n only in details of the optical lens assembly 2o, in particular how the heating element 18n is housed within a lens mount wall of the lens mount 6o. Heating element 18n is placed in an annular space 53o between the lens cap 8n and the lens mount 7o. Lens mount 7o comprises a protrusion <NUM>, which contacts a lateral surface of front elements 13n. Protrusion <NUM> covers the heating element 18n and shields it from the outer environment as well as from the front element 13n.

In a preferred variant of the camera module 1o, the lens mount 7o may be made of metal, in particular aluminium. This way, the protrusion <NUM> serves as a heat transfer component for transferring heat to the front element 13n.

It is, however, also possible to produce the lens 7o from plastic material. In this case, it is in particular possible to embed the wiring 19n in the material of the lens mount wall 50o by over-moulding the wiring 19n. Further, parts at the front end of the lens holder 7o, in particular protrusion <NUM>, may be formed of a different plastic material, which has a particularly good thermal conductivity. For example, multiple-component injection moulding may be used to form different parts of the lens holder 7o.

A thermal insulator 57o is placed between the heating element 18n and the lens cap 7n. This way, heat dissipation away from the front element 13n is reduced. Heating of the front element 13n is particularly efficient. Thermal insulator 57o may, e.g., be made of a plastic material. Thermal insulator 57o may be formed integrally with the lens mount 7o, e.g. by multi-component injection moulding. It is also possible to attach a thermal insulator 57o to the lens holder 7o, in particular by over-moulding the heating element 18n.

In <FIG>, a further embodiment of a camera module 1p is shown. Camera module 1p is similar to camera module 1n, so that corresponding components are not discussed in detail again.

Camera module 1p differs from camera module 1n in details of the optical lens assembly 6p, in particular how the heating element 18n is housed within a lens mount wall of the lens mount 6p. Heating element 18n is placed between a portion of the lens holder wall 50p and a spacer ring <NUM>, which is used to position the front element 13n. Spacer ring <NUM> may, preferably, be made of a metal, in particular of aluminium and/or brass. This way, spacer ring <NUM> serves as a heat transfer component for transferring heat to the front element 13n. Particularly preferably, spacer ring <NUM> may contact the front element 13n along several surfaces, e.g. along the lateral surface end parts of the second surface, facing away from the object side of the optical lens arrangement 2p. This way, heat is distributed particularly efficiently and homogeneously to the front element 13n.

In the shown embodiment, spacer ring <NUM> also contacts a further lens element <NUM> of the lens arrangement 11n. This way, also the further lens element <NUM> may be heated via the heating element 18n.

A gap <NUM> is formed between the spacer ring <NUM> and parts of the lens holder wall 50p. Gap <NUM> serves for thermal insulation between the spacer ring <NUM> and further parts of the lens holder wall 50p, leading to an efficient heat transfer to the front element 13n.

In <FIG>, a further embodiment of a camera module 1q is shown. Camera module 1q mainly coincides with camera module 1p shown in <FIG>.

Claim 1:
Optical lens assembly (2i; 2j; <NUM>; 2n; 2o; 2p; 2q), in particular for a camera module (1i; <NUM>; 1n; 1o; 1p; 1q), comprising
<NUM>. a lens mount (6j; <NUM>; 6n; 6o; 6p; 6q),
<NUM>. a lens arrangement (11j; 11n) of one or more lens elements (<NUM>) inside the lens mount (6j; <NUM>; 6n; 6o; 6p; 6q), and
<NUM>. a heating element (18i; 18j; 18n) for heating at least one of the one or more lens elements (<NUM>), in particular a front element (13i; 13j; 13n) at an object-side of the lens arrangement (11j; 11n),
<NUM>. wherein the lens mount (6j; <NUM>; 6n; 6o; 6p; 6q), in particular a lens holder (7j; <NUM>; 7n; 7o; 7p) thereof, comprises a lens mount wall (<NUM>; <NUM>; 50n; 50o; 50p) defining an inner space for accommodating the one or more lens elements (<NUM>) of the lens arrangement (11j; 11n), characterized in that the heating element (18i; 18j; 18n) is housed within the lens mount wall (<NUM>; <NUM>; 50n; 50o; 50p) so that it has no direct contact with the one or more lens elements (<NUM>; 13i; 13j; 13n).