Lighting device with electrochromic film

Abstract

The invention relates to a lighting device (200) for a motor vehicle, comprising at least one lighting module (210) arranged and configured to perform at least one lighting function, said lighting module being contained within a housing (201) of said lighting device. The lighting device comprises: - an electrochromic film (100) that is at least partially transparent, the electrochromic film being arranged in the lighting device so as to be traversed by light rays (211; 212) emanating from the lighting module; - a control element (15) for the electrochromic film, said control element being capable of applying a first electrical voltage to the electrochromic film so as to increase the opacity of the electrochromic film; wherein the control element is configured to apply said at least one electrical voltage to the electrochromic film when the lighting module is deactivated. FIG. 2

Description

Title of the invention: Lighting device with electrochromic film

[0001] The present invention relates to the field of lighting devices for motor vehicles. The invention applies in particular, but not exclusively, to lighting devices comprising at least one lighting module inserted in a housing of the lighting device.

[0002] A motor vehicle lighting module is generally deactivated when ambient light is high, particularly in daytime driving situations. Such a lighting module is generally located behind an external lens of a lighting device, such as a motor vehicle's headlight.

[0003] Therefore, during the day, the deactivated lighting module becomes visible behind the external glass to an observer outside the motor vehicle, which degrades the aesthetic appearance of the lighting device.

[0004] Indeed, lighting devices comprise several light modules, including lighting and signaling modules. Their respective shapes and arrangements form a signature of the lighting device. Deactivating the lighting modules during the day thus creates discontinuities in the lighting device signature.

[0005] There is therefore a need to improve the external aesthetic appearance of a lighting device, in particular its signature, regardless of the driving situation, without however negatively impacting the lighting or signaling functions, which are essential to driving the vehicle.

[0006] The present invention improves the situation.

[0007] A first aspect of the invention relates to a lighting device for a motor vehicle, comprising at least one lighting module arranged and configured to perform at least one lighting function, said lighting module being contained within a housing of said lighting device, further comprising: - an electrochromic film that is at least partially transparent, the electrochromic film being arranged in the lighting device so as to be traversed by light rays from the lighting module; - an electrochromic film control element, said control element being capable of applying a first electrical voltage to the electrochromic film so as to increase the opacity of the electrochromic film. The control element is configured to apply said at least one first electrical voltage to the electrochromic film when the lighting module is deactivated.

[0008] Thus, an electrochromic film whose opacity is controllable by a control element can be placed in an intercept between the lighting module and the outside of the vehicle. This makes it possible to conceal the lighting module, at least partially, when it is deactivated, by applying an electrical voltage to the electrochromic film. Furthermore, an electrochromic film is less expensive and more efficient than a polymer dispersed liquid crystal (PDLC) film.

[0009] According to embodiments, the electrochromic film can be made totally opaque by application of said first electrical voltage by the control element for a first duration.

[0010] Thus, the lighting module is completely concealed, and its visual appearance is replaced by that associated with the electrochromic film. It should be noted that the electrochromic film, after the first voltage is applied, can have a given color or be black, which makes it possible to harmonize the external appearance of the lighting device with the color of the bodywork or according to the signature of the lighting device, for example.

[0011] According to some embodiments, the electrochromic film can have a transparency greater than 75% in the absence of the application of the first electrical voltage by the control element. Preferably, the transparency of the electrochromic film in the absence of the application of the first electrical voltage by the control element is greater than 90%.

[0012] Thus, the electrochromic film does not impair the lighting function performed by the lighting module. Transparency is understood to mean the ratio of outgoing light energy to incident light energy of rays arriving in a direction substantially normal to a surface of the electroluminescent film, and passing through its thickness.

[0013] According to embodiments, the electrochromic film may comprise a plurality of layers, including at least one layer of electrochromic material separated from an ion storage layer by an electrolyte, the ion storage layer being located between a first layer of conductive substrate and the electrolyte and the layer of electrochromic material being located between a second layer of conductive substrate and the electrolyte.

[0014] The transparency / opacity of the electrochromic film is thus controlled by controlling the degree of oxidation of the electrochromic material layer, an oxidation which is also reversible. It is therefore possible to increase and then decrease the opacity of the electrochromic film.

[0015] In addition, the first conductive substrate layer and the second conductive substrate layer may comprise a transparent conductive oxide material, for example an indium-tin oxide.

[0016] Thus, the substrate layers, in addition to their role as mechanical support, can form first and second electrodes respectively, to apply a difference voltage and cause ions to migrate in one direction or the other between the ion storage layer and the electrochromic material layer.

[0017] In addition or alternatively, the electrochromic film may further comprise a first layer of flexible and transparent material and / or a second layer of flexible and transparent material, the first layer of conductive substrate being included between the first layer of flexible and transparent material and the ion storage layer, and the second layer of conductive substrate being included between the second layer of flexible and transparent material and the electrochromic material layer.

[0018] Thus, the layers of flexible and transparent material allow mechanical and chemical protection of the layers they contain, without increasing the overall transparency of the electrochromic film.

[0019] According to embodiments, the lighting device may include an outer glass arranged to be traversed by the light rays from the lighting module, and the electrochromic film may be arranged opposite the outer glass.

[0020] The outer glass can be a transparent cover suitable for closing an internal space in the lighting device in which the lighting module is arranged. This facilitates the installation of the electrochromic film in the lighting device.

[0021] In addition, the electrochromic film can cover at least part of an inner surface of the outer glass, so as to be arranged between the outer glass and the lighting module.

[0022] Thus, the electrochromic film is protected from the outside of the motor vehicle by the outside glass, which extends the life of the electrochromic film.

[0023] According to embodiments, the control element can be configured to apply the first electrical voltage to the electrochromic film upon detection of a deactivation of the lighting module, and can further be configured to apply a second electrical voltage opposite to the first electrical voltage to the electrochromic film upon detection of an activation of at least one lighting function of the lighting module, the application of the second electrical voltage increasing the transparency of the electrochromic film.

[0024] Thus, reversible control of the transparency / opacity of the electroluminescent film is possible, depending on the activation state of the lighting module. This makes it possible to improve the aesthetic appearance of the lighting device without negatively impacting the lighting functions that are essential for driving the vehicle.

[0025] In addition, the control element can be configured to detect the deactivation of the lighting module and to detect the activation of said at least one lighting function, from an operating state of a daytime running light module of the lighting device.

[0026] Thus, the detection of the operating state is facilitated, in particular when the control element is not capable of controlling the activation / deactivation of the lighting module.

[0027] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings in which:

[0028] [Fig. 1] illustrates an electrochromic film comprising a plurality of layers according to embodiments of the invention;

[0029] [Fig.2] illustrates a side view in cross-section of a lighting device according to embodiments of the invention;

[0030] [Fig.3] illustrates a front view of a lighting device according to embodiments of the invention.

[0031] The description focuses on the characteristics that distinguish the lighting device from those known in the state of the art.

[0032] The [Fig.1] presents an electrochromic film structure 100 according to embodiments of the invention.

[0033] The electrochromic film comprises at least one layer of electrochromic material 105 and an ion storage layer 103, separated by an electrolyte 104.

[0034] An electrical voltage can be applied between the electrochromic material layer 105 and the ion storage layer 103, so as to allow the migration of ions from the ion storage layer 103 to the electrochromic material layer 105, thereby oxidizing the electrochromic material layer. For this purpose, a first electrode can be formed by a first conductive substrate layer 102 and a second electrode can be formed by a second conductive substrate layer 106.

[0035] No restrictions are attached to the materials of the first and second layers of conductive substrate 102 and 106. For example, the first layers of conductive substrate 102 and 106 may include a non-conductive material on which a conductive coating is deposited, such as a transparent conductive oxide coating, also called TCO for “Transparent Conductive Oxides”, in English, for example a thin layer of indium-tin oxide, also called ITO for “Indium-Tin Oxide” in English.

[0036] Electrochromic means a material that changes color when an electrical voltage is applied to it for a short time. The color change is due to the fact that only a specific type of wavelength, for example, wavelengths of a specific value or within a specific visible color spectrum, can be reflected by the electrochromic material layer, depending on the value of the applied electrical quantity.

[0037] According to the invention, the electrochromic material layer 103 and 104 is at least partially transparent at rest, that is to say when no electrical voltage is applied to the electrochromic film, the opacity of the electrochromic material layer increases by applying a first electrical voltage to the electrochromic film. The electrochromic material layer then appears more opaque and of a color determined by the characteristics of the electrochromic material used, the thickness of the electrochromic layer 105, and the voltage applied to the electrochromic film 100.

[0038] A control element 15 is capable of controlling an electrical voltage applied between the electrochromic material layer 105 and the ion storage layer 103. For example, the storage element can apply the electrical voltage to the first and second substrate layers 102 and 106, so as to force a migration of ions towards the electrochromic material layer 105, via the electrolyte 104, which increases the opacity of the electrochromic material layer 105 and therefore of the electrochromic film 100.

[0039] The increase in opacity is due to an oxidation phenomenon of the electrochromic material layer 105, made possible by the migration of ions towards the electrochromic material layer 105. It should be noted that it is possible to adjust the level of oxidation, and therefore the opacity level of the electrochromic material layer, progressively according to the value of the voltage applied to the electrochromic film 100. Such oxidation is reversible by applying a voltage opposite to the voltage applied by the control element 15. The electrochromic material layer 105 can therefore be made more transparent, up to its resting state, by applying an opposing voltage, referred to as the second voltage hereafter, to the electrochromic film 105, in order to reduce the oxidation of the electrochromic material layer. The ions thus migrate in the opposite direction towards the ion storage layer 103. Examples are given below by way of illustration.

[0040] In its resting state, the electrochromic material layer can be transparent, and may in particular have a degree of transparency greater than 90%, preferably greater than 95%. A first voltage, for example equal to IV, is applied to the electrochromic film 100 for a given duration, causing partial or total oxidation of the electrochromic material layer 105, thus increasing its opacity and giving it a given color. The opacity can, in particular, be increased, depending on the duration and value of the first voltage, up to total opacity, i.e., no visible light ray can pass through the electrochromic material layer 105.

[0041] Applying a second electrical voltage by the control element 15, opposite to the first electrical voltage, for example equal to -IV, for a second given duration, for example equal to the first duration, makes it possible to increase the transparency of the electrochromic material layer 105.

[0042] Thus, the control element 15 is capable of controlling the state of the electrochromic material layer 105 entering a resting state, in which the electrochromic material layer trochrome 105 is at least partially transparent, with in particular a high level of transparency, and an oxidized state (partially oxidized or totally oxidized), in which the level of transparency is reduced (or the level of opacity is increased, which is equivalent), for example to a level of total opacity.

[0043] The first and second durations may be a few seconds, and may be equal. However, no restrictions are attached to the first and second durations according to the invention.

[0044] The electrochromic film 100 may further comprise a first layer of flexible and transparent material 101 and a second layer of flexible and transparent material 107. The first layer of flexible and transparent material 101 is arranged such that the first layer of conductive substrate 102 is located between the first layer of flexible and transparent material 101 and the ion storage layer 103. The second layer of flexible and transparent material 107 is arranged such that the second layer of conductive substrate 106 is located between the electrochromic material layer 105 and the second layer of flexible and transparent material 107.

[0045] The use of layers of flexible and transparent material on either side of the electrochromic film 100 provides mechanical and chemical protection for the electrochromic film 100. Furthermore, they do not reduce the overall transparency of the electrochromic film 100 when the layer of electrochromic material 105 is at rest. The flexible and transparent material can, for example, be a layer of glass or plastic. Indeed, when the thickness of a glass layer is ultra-thin, particularly on the order of a few tens of micrometers, the glass layer is flexible, and the electrochromic film 100 can thus be flexible.

[0046] The use of thin, or even ultra-thin, layers and suitable materials for the electrochromic film 100 makes it possible both to make the electrochromic film 100 flexible, but also to have a high overall level of transparency when the layer of electrochromic material 105 is at rest.

[0047] The overall transparency level corresponds to the ratio of light rays 111 exiting the electrochromic film to the incident light rays 110. The thickness of the layers of the electrochromic film 100 and their respective materials may, in particular, be such that the overall transparency level, when the layer of electrochromic material 105 is at rest, is greater than 75%, or even greater than 90%, or even greater than 95%.

[0048] When the first electrical voltage is applied during the first given duration, the overall transparency level can fall below 10%, or even below 5%, or even reach 0% in the case of total opacity, due to the oxidation of the electrochromic material layer 105.

[0049] The term “film” refers to an object in which one dimension is small compared to the other two dimensions, in particular more than 10 times smaller, or even more than 100 times smaller. Electrochromic film 100 meets this definition in that its thickness, i.e., its dimension along the X-axis in [Fig. 1], is at least 10 times smaller than its dimensions along the Z and Y axes. It will therefore be understood that the width along the Y-axis shown in [Fig. 1] is given for illustrative purposes only, but that the width along the Y-axis is much greater than the thickness along the X-axis in reality.

[0050] The electrochromic material of layer 105 can for example be a tungsten oxide, such as tungsten trioxide WO3 for example, the properties of which are described in the publication “Review of the versatility of Tungsten Oxide Coatings”, Cezarina C. Mardare and Achim W. Hassel, Phys. Status Solidi A, 2019, published by Wiley-VCH Verlag GmbH&Co KHaA, Weinheim.

[0051] Alternatively, the electrochromic material of layer 105 may be a polymer, such as a PEDOT-type polymer, or poly(3,4-ethylenedioxythiophene), or PEDOT:Tosylate.

[0052] Of course, other materials can be used as long as they have properties suitable for automotive applications, such as high ionic conductivity and a transparent or colorless appearance in its resting state, and are flexible. Furthermore, the material can be packaged as a solid cell. The electrochromic material can, in particular, be an organic or an inorganic material.

[0053] The electrochromic material may be a transparent conductive oxide, or TCO. In particular, among organic electrochromic materials, the electrochromic material may be a transparent conductive polymer of the type PEDOT:PSS, PEDOTdos, PMMA, T34bT or polycarbonate, namely: PEDOT:PSS denotes poly(3,4 ethylenedioxythiophene): sodium poly(styrene-sulfonate); PEDOT:Tos denotes poly(3,4 ethylenedioxythiophene):Tosylate; PMMA stands for Polymethyl MethAcrylate; T34bT stands for 2-alkylthieno[3,4-b]thiophene.

[0054] Fig. 2 presents a cross-sectional and side view of a lighting device 200 according to embodiments of the invention.

[0055] The lighting device 200 includes at least one lighting module 210 capable of performing at least one lighting function, such as a lighting and / or signaling function.

[0056] For example, the lighting module 210 can perform: - a dipped beam function, also called LB for “Low Beam” in English; - a high beam function, also called HB for 'High Beam'; and / or - a position light function, also called PL for “Position Lighting” in English.

[0057] The lighting module 210 may in particular be capable of performing the three functions LB, HB and PL mentioned above, according to certain embodiments of the invention.

[0058] In order to perform one or more of these functions, the lighting module 210 includes at least one light source not shown in [Fig. 2]. Such a source may be a pixelated source comprising a plurality of individually controllable light elements. The light elements may, for example, be electroluminescent light elements, controllable by the electric current supplied to each of them. However, there are no restrictions on the technology associated with the light source, or light sources, of the lighting module 210.

[0059] The lighting module 210 is thus able to project light beams 211 outside the lighting module 210, towards an external glass 202 of the lighting device 200, the external glass 202 being at least partially transparent, preferably with a high level of transparency, greater than 75%, in particular greater than 90%, or even greater than 99%.

[0060] The lighting module 210 can be arranged in a housing 201 of the lighting device 200, the housing 201 being shaped to receive the lighting module 210, and to fix and adjust the orientation of the lighting module 210 inside the lighting device.

[0061] When the lighting module 210 is not activated, i.e. when no light beam 211 is projected, which most often occurs in daytime driving situations, the control element 15 is able to apply a first voltage to the electrochromic film so as to increase its opacity compared to its resting state, by partial or total oxidation of the electrochromic layer 105. Preferably, the control element 15 applies the first voltage for a first duration, so that the transparency of the electrochromic film 100 is less than 10%, for example less than 5%.

[0062] When the lighting module 210 is activated, that is, when light beams 211 are projected to perform at least one lighting function, the control element 15 is capable of increasing the transparency of the electrochromic film 100 relative to its state obtained after the application of the first voltage, by applying a second voltage with the opposite sign to the first voltage. Preferably, the second voltage is applied for a second duration so that the layer of electrochromic material 105 returns to its state of rest, that is to say its minimum oxidation state, in which the transparency of the electrochromic film is greater than 90%, in particular greater than 95%, or even greater than 99%.

[0063] The application of the first voltage during the first duration can be implemented by the control element 15 upon detection of the deactivation of the lighting module 210. In addition, the application of the second voltage during the second duration can be implemented by the control element 15 upon detection of the deactivation of the lighting module 210. Thus, an external observer is not able to see inside the housing 201 when the lighting module is deactivated, which makes it possible to improve the external aesthetic appearance of the lighting device 200, with low energy consumption, and without inducing bulk of the lighting device 200 since the electrochromic film 100 has a thinness, less than 1mm in particular.

[0064] In order to detect the activation state of the lighting module 210, the control element 15 is capable of communicating with a control module of the lighting module 210, which can be a control module dedicated to the lighting module 210, a control module dedicated to the lighting device 200 or a centralized vehicle control module, of the ECU type for example, for “Electronic Control Unit”.

[0065] Alternatively, the control element 15 is capable of activating / deactivating the lighting module 210, or even of controlling all the light modules of the lighting device 200. In this variant, the control element 15 is capable of determining the activation state of the lighting module 210 itself, and of controlling the voltage applied to the electrochromic film 100 accordingly.

[0066] In addition, the electrochromic film 100 can advantageously be flexible, which makes it easier to arrange it in the lighting device 200. In particular, it can be arranged against the outer glass 202 to adopt the same curvature as an inner surface of the outer glass 202. Alternatively, the electrochromic film is flat, without curvature, and extends in a plane substantially parallel to the YZ plane.

[0067] The electroluminescent film 100 is thus arranged so as to be traversed by light rays 211 projected by the lighting module 210 in a direction substantially along the X axis, that is to say light rays forming angles less than 20° with the X axis.

[0068] Fig. 3 illustrates a front view of the lighting device 200, from outside the motor vehicle, according to embodiments of the invention.

[0069] The lighting device 200 according to the invention comprises at least one lighting module 210 as described above. In the example of [Fig.3], the lighting device 200 comprises a first lighting module 210.1 and a second lighting module 210.2.

[0070] Each of the lighting modules 210.1 and 210.2 is capable of projecting light beams outwards from the lighting device 200 to perform at least one lighting function. Such a lighting function may, for example, be a low beam function (LB) or a high beam function (HB). At least one of the lighting modules 210.1 and 210.2 is controllable, for example by a dedicated control module, or by the control element 15, to perform at least one lighting function.

[0071] The lighting device 200 may optionally include one or more signaling modules 302.1, 302.2, and 302.3, capable of emitting light beams outwards from the lighting device to perform a signaling function. The signaling module may, for example, be capable of performing a position light (PL) function or a daytime running light (DRL) function. In addition, each signaling module may be capable of performing both position light (PL) and daytime running light (DRL) functions, with only the light intensity emitted by the signaling module varying between the two functions. Such a variation in light intensity can be achieved by activating / deactivating light sources in the signaling module, or by powering the light source(s) using pulse-width modulation, thus varying the duty cycle.

[0072] The light device 200 for motor vehicle is preferably a motor vehicle headlight, for example a motor vehicle front headlight.

[0073] No restrictions are attached to the number of lighting modules and signaling modules included in the lighting device 200, nor to their respective shapes and arrangements, which form the signature of the lighting device 200.

[0074] In the particular example shown in [Fig. 3], the lighting device 300 comprises:

[0075] - a first lighting module 210.1 and a second lighting module 210.2. By For example, the first lighting module 210.1 can perform a low beam (LB) lighting function while the second lighting module 210.2 can perform a high beam (HB) lighting function;

[0076] - a first signaling module 302.1, in two upper and lower parts, a second signaling module 302.2, consisting of two upper and lower parts, and a third signaling module 302.3, also consisting of two upper and lower parts. Each signaling module 302.1, 302.2, or 302.3 is capable of emitting light beams outwards from the lighting device to perform a signaling function. Each signaling module can perform its own signaling function, or alternatively, the signaling modules 302.1, 302.2, and 302.3 can perform the same signaling function(s) and thus be controlled together, for example, by the control element 15 or by a control module. dedicated, not shown on [Fig.3].

[0077] As shown in [Fig.3], a first electroluminescent film 100.1 is arranged in front of the first lighting module 100.1 and a second electroluminescent film 100.2 is arranged in front of the second lighting module 100.2.

[0078] Thus, the opacity of each electroluminescent film 100.1 and 100.2 can be increased when the lighting modules 210.1 and 210.2 are deactivated, which prevents an observer from seeing the lighting modules 210.1 and 210.2 inside the housing 201 of the lighting device 200. For this purpose, as shown in [Fig.3], the dimensions along the Y-axis and along the Z-axis of each electrochromic film 100.1 and 100.2 can be greater than or equal to the dimensions along the Y-axis and along the Z-axis of the lighting module associated with it.

[0079] The activation / deactivation detection of the lighting module can be based on the activation / deactivation state of a signaling module performing a daytime running light (DRL) signaling function. When the DRL signaling module is activated, the lighting module is deactivated, and consequently, the first voltage can be applied by the control element 15 to increase the opacity of the electrochromic film 100. Conversely, when the DRL signaling module is deactivated, the lighting module is activated, and consequently, the second voltage can be applied by the control element 15 to decrease the opacity, or increase the transparency, of the electrochromic film 100.

[0080] The lighting device 200 may include a single outer glass 202 comprising several parts, each part being opposite a lighting module or a signaling module.

[0081] The control element 15 may include a processor configured to communicate unidirectionally or bidirectionally, via one or more buses or via a wired connection, with a memory such as Random Access Memory (RAM), Read Only Memory (ROM), or any other type of memory (Flash, EEPROM, etc.). Alternatively, the memory may include several of the aforementioned types. Preferably, the memory is non-volatile. The processor is capable of executing instructions, stored in the memory, to control the voltage applied to at least one electrochromic film 100. Alternatively, the processor may be replaced by a microcontroller designed and configured to control said at least one electrochromic film 100.

[0082] The present invention is not limited to the embodiments described above by way of example; it extends to other variants.

Claims

Claims

1. Lighting device (200) for a motor vehicle, comprising at least one lighting module (210; 210.1; 210.2) arranged and configured to perform at least one light function, said lighting module being included in a housing (201) of said lighting device, further comprising: - an electrochromic film (100; 100.1; 100.2) at least partially transparent, the electrochromic film being arranged in the lighting device so as to be traversed by light rays (211; 212) coming from the lighting module; - a control element (15) of the electrochromic film, said control element being capable of applying a first electrical voltage to the electrochromic film so as to increase an opacity of the electrochromic film; wherein the control element is configured to apply said at least one first electrical voltage to the electrochromic film when the lighting module is deactivated.

2. Lighting device according to claim 1, wherein the electrochromic film (100) is capable of being totally opaque by application of said first electrical voltage by the control element (15) for a first duration.

3. A lighting device according to claim 1 or 2, wherein the electrochromic film (100) has a transparency greater than 75% in the absence of application of the first electrical voltage by the control element (15).

4. A lighting device according to claim 1 or 2, wherein the electrochromic film (100) comprises a plurality of layers, comprising at least one layer of electrochromic material (105) separated from an ion storage layer (103) by an electrolyte (104), the ion storage layer being comprised between a first layer of conductive substrate (102) and the electrolyte and the layer of electrochromic material being comprised between a second layer of conductive substrate (106) and the electrolyte.

5. A lighting device according to claim 4, wherein the first conductive substrate layer (102) and the second conductive substrate layer (106) comprise a transparent conductive oxide material, for example an indium tin oxide.

6. A lighting device according to claim 4 or 5, wherein further comprising a first layer of flexible and transparent material (101) and / or a second layer of flexible and transparent material (107), the first layer of conductive substrate (102) being comprised between the first layer of flexible and transparent material and the ion storage layer (103), and the second layer of conductive substrate (106) being comprised between the second layer of flexible and transparent material and the layer of electrochromic material (105).

7. Lighting device according to one of the preceding claims, comprising an outer glass (202) arranged to be crossed by the light rays coming from the lighting module (210), and in which the electrochromic film (100) is arranged opposite the outer glass.

8. A lighting device according to claim 7, wherein the electrochromic film (100; 100.1; 100.2) covers at least a portion of an inner surface of the outer glass (202), so as to be arranged between the outer glass and the lighting module (210; 210.1; 210.2).

9. Lighting device according to one of the preceding claims, wherein the control element (15) is configured to apply the first electrical voltage to the electrochromic film (100; 100.1; 100.2) upon detection of a deactivation of the lighting module (210; 210.1; 210.2), and is further configured to apply a second electrical voltage opposite to the first electrical voltage to the electrochromic film upon detection of an activation of at least one light function of the lighting module, the application of the second electrical voltage increasing a transparency of the electrochromic film.

10. Lighting device according to claim 9, wherein the control element (15) is configured to detect the deactivation of the lighting module (210; 210.1; 210.2) and to detect the activation of said at least one light function, from an operating state of a daytime running light module of the lighting device (200).

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