Glass element including condensation detector

Abstract

The invention relates to a glass element comprising a glass (2) comprising a first glass sheet (4) having a first face and a second face, the glass (2) having a first edge (5) and a second edge (6) opposite the first edge (5), the glass element comprising a light source (8) configured to emit a light beam (9), and a light detector (10) configured to detect the light beam (9) emitted by the light source (8), the light source (8) is arranged such that a light beam (9) propagates in the first glass sheet (4) from the first edge (5) to the second edge (6) by several total internal reflections on the first face (F4) and the second face (F3), and the light detector (10) is arranged outside the glass (2) and near the first face relative to the first glass sheet (4), the light detector (10) is configured to receive the light beam (9) passing through at least part of the detection surface (11).

Description

Technical Field

[0001] The invention relates to a glass element for a vehicle, comprising a condensation detector. Background Art

[0002] During the occurrence of condensation droplets on the inner surface of a glass unit of a vehicle, it is known to manually activate the ambient temperature and / or ventilation regulator in the vehicle in order to control the evaporation of the condensation droplets.

[0003] However, this approach can distract the vehicle driver. Furthermore, this approach is only feasible when condensation droplets have already occurred and have impaired the driver's visual perception through the glass unit.

[0004] To this end, document EP3552004 describes a capacitive condensation sensor comprising interdigitated electrodes inserted into a glass unit. During the formation of condensation on the inner surface of the glass unit, the capacitance measured by the sensor changes. Thus, visual detection of condensation can be omitted and the driver's distraction is thereby reduced.

[0005] However, the sensor disclosed in document EP 3552004 is not able to detect the smallest droplets of condensation. Therefore, the driver may already be aware of the condensation before the capacitive sensor detects it.

[0006] Furthermore, capacitive detection of condensation may have a delay of about ten seconds or so. For example, known condensation sensors include a material that is able to absorb water from condensation droplets. In this case, the sensor measures the capacitance of the material, and the delay of the sensor may depend on the water absorption kinetics of the material. This delay may be sufficient to cause the condensation density to increase and thus impair the driver's visual perception. Summary of the invention

[0007] It is an object of the present invention to propose a solution for automatically detecting condensation on the surface of a glass unit of a vehicle, and preferably before it can be perceived by the driver.

[0008] In the context of the present invention, this object is achieved by a glazing element for a vehicle, the glazing element comprising a glazing unit extending along a main surface, the glazing unit comprising a first glass sheet, the first glass sheet having a first face preferably parallel to the main surface and a second face, the second face being opposite to the first face with respect to the first glass sheet, the glazing unit having a first edge and a second edge opposite to the first edge, the first face being able to come into contact with the interior environment of the vehicle and to support the nucleation of condensation droplets,

[0009] The glass element comprises a light source configured to emit a light beam, and a light detector configured to detect the light beam emitted by the light source, the light source being arranged so that the light beam propagates from a first edge to a second edge in the first glass sheet by a number of total internal reflections on the first face and the second face,

[0010] The light detector is arranged outside the glass unit and on the side of the first face relative to the first glass sheet,

[0011] The first face comprises a detection surface having a surface area greater than 0.01% (inclusive) of the total surface area of ​​the first face, in particular greater than 1% (inclusive) of the total surface area of ​​the first face, and preferably greater than 20% (inclusive) of the total surface area of ​​the first face,

[0012] The light detector is configured to receive the light beam that passes through at least a portion of the detection surface.

[0013] The invention is advantageously completed by the following features, which are used alone or in any technically possible combination thereof: the glass unit is a laminated glass unit, the glass unit comprises a second glass sheet and an interlayer arranged between the first glass sheet and the second glass sheet, the second face is on a side of the interlayer relative to the first glass sheet, the first glass sheet is formed of a first glass having a first refractive index n1, the glass unit comprises a first material, the first material covers the second face on a side of the interlayer relative to the second face and has a second refractive index n2, the second refractive index n2 is strictly smaller than the first refractive index n1, - the first material covering the second face at least partially forms a sandwich, The first glass has a first absorption coefficient a1 for the light beam, the second glass sheet is formed of the second glass, the second glass has a second absorption coefficient a2 for the light beam, the first absorption coefficient a1 is strictly smaller than the second absorption coefficient a2, and the first absorption coefficient a1 is preferably smaller than 0.5 cm -1 , especially less than 0.1cm -1 , the light source extends along the first edge, preferably from one corner of the glass unit, in particular to another corner of the glass unit, the light beam has a wavelength between 780 nm (inclusive) and 2500 nm (inclusive), in particular between 800 nm and 1100 nm (inclusive), and preferably between 900 nm and 1000 nm (inclusive), the detection surface is defined by a portion of the first face extending along an element selected from: a lateral edge of the glass unit, a lateral edge of the glass unit on the driver's side, a lower lateral edge of the glass unit, a corner of the glass unit and a lower corner of the glass unit on the driver's side, - the light detector does not have a filter configured to transmit a light beam having a wavelength only between 380 nm (inclusive) and 780 nm (inclusive), - the light detector has a field of view, the arrangement and the field of view of the light detector being configured such that the light detector detects the light beam passing through the detection surface, - the first edge is a conductive side edge of the glass unit, - the glass element comprises a housing configured to support a rearview mirror of the vehicle, the light detector being arranged in the housing, the glass unit comprises a light absorbing layer arranged on a portion of the first face, the light absorbing layer forming a pattern on the first face, the light absorbing layer having a transmittance greater than 0.7, preferably greater than 0.9, for a wavelength range between 380 nm (inclusive) and 780 nm (inclusive), and having a transmittance less than 0.3, preferably less than 0.1 for a wavelength range between 780 nm (exclusive) and 1100 nm (inclusive), - the light absorbing layer is formed of a second material, the second material is a conductive and / or semi-conductive oxide, and the second material is preferably indium tin oxide, - parts of the pattern have a width relative to the main surface of less than 1 cm, preferably less than 5 mm, - the pattern forms an array of stripes on the detection surface, the stripes preferably being parallel to each other, The second material is indium tin oxide doped with at least one metal element and is configured to have maximum light absorption for wavelengths between 780 nm and 1000 nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other features, objects and advantages of the present invention will appear from the following description, which is purely illustrative and non-limiting and which must be read in conjunction with the accompanying drawings, in which: [ Figure 1 ]- Figure 1 A glass element according to an embodiment of the present invention is schematically shown. [ Figure 2 ]- Figure 2 Schematically shows a cross section of a glass element according to one embodiment of the present invention, [ Figure 3 ]- Figure 3 A glass element according to an embodiment of the present invention is schematically shown. [ Figure 4 ]- Figure 4 Schematically showing the pattern formed by the layers deposited on the first side of the glass unit, [ Figure 5 ]- Figure 5 The results of the measurement of the intensity detected in the absence of condensation are shown schematically. [ Figure 6 ]- Figure 6 Schematic representation of the measurement results of the intensity detected in the presence of condensation on the first side, [ Figure 7 ]- Figure 7 The absorption from the material of the light absorbing layer is shown as a function of the wavelength of the incident light beam.

[0015] In all the drawings, similar elements are marked with the same reference numerals. definition

[0016] A "glass unit" is understood to mean a structure comprising at least one organic or mineral glass sheet, which is suitable for installation in a vehicle. A "laminated glass unit" is understood to mean a glass assembly comprising at least two glass sheets and an interlayer made of a plastic material, preferably viscoelastic, separating the two glass sheets. The interlayer may comprise one or several viscoelastic polymer layers, such as polyvinyl butyral (PVB) or ethylene-vinyl acetate copolymer (EVA). The interlayer film is preferably standard PVB or acoustic PVB. Acoustic PVB may comprise three layers: two standard PVB outer layers and an inner PVB layer comprising a plasticizer to make the inner layer less rigid than the outer layer.

[0017] It will be appreciated that for a predetermined wavelength, preferably the wavelength of the light beam emitted by the light source, one refractive index is greater than the other refractive index.

[0018] The "transmittance" of a layer is understood to mean the transmittance of the layer measured for an incident light beam in the direction normal to the main plane according to which the glazing unit extends. The transmittance is defined as the ratio of the intensity of the light beam transmitted by the layer to the intensity of the light beam incident on the layer.

[0019] The glass unit of the glass element according to all embodiments of the present invention has a shape and geometry configured to be installed on a vehicle according to a predetermined single position. Thus, the lateral edge of the glass unit on the driver's side, the lateral edge of the glass unit on the passenger's side, the upper lateral edge of the glass unit and the lower lateral edge of the glass unit can be defined relative to the predetermined position. In the same way, the upper corner of the glass unit on the driver's side, the upper corner of the glass unit on the passenger's side, the lower corner of the glass unit on the driver's side and the lower corner of the glass unit on the passenger's side can be defined relative to the predetermined position.

[0020] The “driver's side edge” of the glass unit is understood to be the lateral edge of the glass unit on the driver's side when the glass unit is mounted on the vehicle according to an individual position predetermined by the shape and geometry of the glass unit.

[0021] The "passenger side edge" of the glass unit is understood to mean the lateral edge of the glass unit on the passenger side opposite the driver side when the glass unit is mounted on the vehicle according to a single position predetermined by the shape and geometry of the glass unit.

[0022] An “upper lateral edge” of a glass unit is understood to mean a lateral edge of the glass unit which is located at the upper part of the glass unit when the glass unit is mounted on the vehicle according to a single position predetermined by the shape and geometry of the glass unit.

[0023] A “lower lateral edge” of a glass unit is understood to mean a lateral edge of the glass unit which is located in the lower part of the glass unit when the glass unit is mounted on the vehicle according to a single position predetermined by the shape and geometry of the glass unit.

[0024] The “driver's side upper corner” of the glass unit is understood to mean the corner of the glass unit which is located on the upper part of the glass unit on the driver's side when the glass unit is mounted on the vehicle according to a single position predetermined by the shape and geometry of the glass unit.

[0025] The “driver's side lower corner” of the glass unit is understood to mean the corner of the glass unit which is located in the lower part of the glass unit on the driver's side when the glass unit is mounted on the vehicle according to a single position predetermined by the shape and geometry of the glass unit.

[0026] "Visible wavelengths" are understood to be wavelengths between 380 nm and 780 nm. DETAILED DESCRIPTION Overall structure of glass element 1

[0027] refer to Figure 1 and Figure 2 One aspect of the invention is a glass element 1 for a vehicle. The glass element 1 comprises a glass unit 2. The glass unit 2 extends along a main surface 3. The glass unit 2 comprises a first glass sheet 4. The first glass sheet 4 has a first face F4 and a second face F3. The first face F4 and the second face F3 may be parallel to the main surface 3. The second face F3 is opposite to the first face 4 relative to the first glass sheet 4.

[0028] The glass unit 2 has a first edge 5 and a second edge 6 opposite the first edge 5. The first face F4 is adapted to be in contact with the interior environment of the vehicle. The geometry of the glass element 1 may be configured such that, when the glass element 1 is installed in the vehicle, the first face F4 is located inside the vehicle. The first edge 8 and the second edge 9 may be lateral edges on the driver's side and the passenger's side, which can extend along at least a vertical component when the glass element 1 is installed in the vehicle. The geometry of the glass element 1 may be configured such that, when the glass element 1 is installed in the vehicle, the first edge 5 is located on the passenger's side of the vehicle. The first face F4 can support the nucleation of condensation droplets 7.

[0029] The glass element 1 comprises a light source 8. The light source 8 is configured to emit a light beam 9. The glass element 1 comprises a light detector 10 configured to detect the light beam 9 emitted by the light source 8. The light source 8 is arranged such that the light beam 9 propagates through the first glass sheet 4 from the first edge 5 to the second edge 6 by several total internal reflections on the first face F4 and the second face F3.

[0030] The first face F4 separates the glass unit 2 from the surrounding air. Therefore, the light beam 9 can be totally internally reflected in the first glass sheet 4 on the first face F4.

[0031] The second face F3 may separate the glass unit from the surrounding air. As a variant, the glass unit 2 may be a laminated glass unit. Thus, the light beam 9 may be totally internally reflected in the first glass sheet 4 on the second face F3.

[0032] The glass unit 2 may include a second glass sheet 12 and an interlayer 13 disposed between the first glass sheet 4 and the second glass sheet 12. The second face F3 is located on a side of the interlayer 13 relative to the first glass sheet 4. The first glass sheet 4 is formed of a first glass having a first refractive index n1. The glass unit 2 may include a first material that covers the second face F3 on a side of the interlayer 13 relative to the second face F3 and has a second refractive index n2. The second refractive index n2 is strictly smaller than the first refractive index n1. Therefore, the light beam 9 may be totally internally reflected in the first glass sheet 4 on the second face F3.

[0033] The first material covering the second face F3 may at least partially form an interlayer 13. The material covering the second face F3 may be PVB forming an interlayer 13. Thus, the manufacture of the waveguide formed by the first glass sheet 4 is simplified, since it is not necessary to modify the structure of the laminated glass unit 2 in order to use the first glass sheet 4 as a waveguide. In fact, PVB has a refractive index that is lower than that of glass for wavelengths in the visible and infrared ranges.

[0034] The light detector 10 is arranged outside the glass unit 2 and on the side of the first face F4 relative to the first glass sheet 4. The first face F4 comprises a detection surface 11 having a surface area greater than 0.01% (inclusive) of the total surface area of ​​the first face F4, in particular greater than 0.1% (inclusive) of the total surface area of ​​the first face F4, preferably greater than 20% (inclusive) of the total surface area of ​​the first face F4, preferably greater than 50% (inclusive) of the total surface area of ​​the first face F4, and preferably greater than 70% (inclusive) of the total surface area of ​​the first face F4.

[0035] The light detector 10 is configured to detect at least part of the light beam 9 passing from the first glass sheet 4 to the light detector 10 through the detection surface 11. Thus, the first glass sheet 4 forms a waveguide on which condensation drops can form. In fact, due to the relationship between the refractive indices of air and / or a first material in contact with the first glass sheet 4, the light beam 9 can propagate from the light source 8 to the light detector 10 by total internal reflection on the first face F4 and the second face F3. During the nucleation of the condensation droplets 7 on the first face F4, part of the light beam 9 is transmitted to the interface formed between the glass and the first glass sheet 4 and the liquid water of the condensation droplets 7. Thus, the light detector 10 can detect the presence of one or more condensation drops 7 over the entire detection surface 11 for a predetermined detection surface 11. In fact, the inventors have found that the condensation drops 7 are preferentially formed at predetermined positions of the first face F4, which positions form the detection surface 11. Thus, the glass element 1 makes it possible to detect the presence of condensation drops 7 on the first face F4 early before the condensation drops 7 are visually detected by the vehicle driver.

[0036] The glass element 1 may include a control unit 16 configured to: - control the emission of a light beam 9 by a light source 8, - receiving data representative of the light beam 9 detected by the light detector 10, - Comparing the data representing the light beam 9 detected by the light detector 10 with the data representing the reference light beam and emitting from this comparison a signal representing the nucleation of a condensation droplet.

[0037] As a variant, the control, reception, comparison and transmission steps described above may be implemented by a control unit of the vehicle's engine. Detection surface 11

[0038] The detection surface 11 can be defined by at least a portion of the first face F4, which extends along at least one element selected from: a lateral edge of the glass unit, a lateral edge of the glass unit on the driver's side, a lower lateral edge of the glass unit, a corner of the glass unit and a lower corner of the glass unit on the driver's side.

[0039] In fact, the inventors have found that the portion of the first face F4 described above is able to support the nucleation of condensation droplets 7 before the condensation droplets 7 nucleate on other portions of the first face F4. Thus, the nucleation of condensation droplets 7 can be detected before the driver of the vehicle can visually detect the condensation droplets 7 on the rest of the first face F4. Light absorption by glass sheets

[0040] The first glass may have a first absorption coefficient a1 of the light beam 9. The second glass sheet 12 may be formed of the second glass. The second glass may have a second absorption coefficient a2 of the light beam 9. The first absorption coefficient a1 may be strictly smaller than the second absorption coefficient a2. Thus, the glass unit 2 may have absorption properties that transmit infrared radiation while allowing the detection of nucleation of condensation droplets on the first face F4.

[0041] The first absorption coefficient a1 can be less than 0.5 cm -1 , and preferably less than 0.1 cm -1 Thus, it is possible to limit the absorption of the light beam 9 during its propagation in the first glass sheet 4 in order to detect condensation, while allowing the glass unit 2 to absorb infrared radiation. The second absorption coefficient a2 may be greater than 2 cm -1 , and preferably greater than 3cm -1 . Light Source 8

[0042] The light source 8 may extend along the first edge 5, preferably from one corner of the glass unit 2, in particular to the other corner of the glass unit 2. The light source 8 may emit a light beam 9 along the first edge 5 to the second edge 6. Thus, the portion of the detection surface 11 where the condensation droplets 7 first appear benefits from the light beam 9, which is less attenuated by the first glass than when it reaches the second edge 6. This makes it possible to maximize the light intensity received by the light detector 10 in order to detect the condensation droplets 7. The first edge 5 may be the driver's side edge of the glass unit 2. Thus, the nucleation of the condensation droplets 7 may be detected before other condensation droplets 7 nucleate on the rest of the first face F4.

[0043] The light source 8 may be configured to emit a light beam 9 having one or more wavelengths selected from the wavelength range between 800 nm and 2500 nm. Thus, the total internal reflection properties of the waveguide formed by the first glass sheet 4 may be increased while using the light beam 9 invisible to the vehicle user.

[0044] The light source 8 may be configured to emit a light beam 9 having one or several wavelengths selected from a wavelength range between 800 nm and 1100 nm. Thus, in addition to the advantages described above for the wavelength range between 800 nm and 2500 nm, the wavelength range between 800 nm and 1100 nm makes it possible to detect the light beam 9 using a conventional light detector 10 configured to detect light beams having wavelengths in the visible wavelength range. In practice, this type of light detector primarily makes it possible to detect near-infrared wavelengths, i.e. wavelengths in the wavelength range between 800 nm and 1100 nm. This leads to a simplification of the manufacture of the glass element 1 and a reduction of the costs associated with this manufacture.

[0045] The light source 8 may be formed by a strip comprising a series of LEDs. The strip may be mounted in contact with the first edge 5 and / or the second edge 6. Photodetector 10

[0046] The light detector 10 is arranged outside the glass unit 2 so as to detect and / or image the light beam 9 from the detection surface 11 and preferably from all points forming the detection surface 11. The light detector 10 has a field of view. The arrangement and field of view of the light detector 10 are configured so that the light detector 10 detects the light beam passing through the detection surface 11.

[0047] The light detector 10 may be a light detector configured to detect a light beam 9 having a wavelength in the visible wavelength range. In practice, this type of light detector primarily makes it possible to also detect wavelengths in the near infrared wavelength range, preferably between 800 nm and 1100 nm. Thus, the manufacture of the glass element 1 may be simplified and the costs associated with this manufacture may be reduced. The light detector 10 may be a light detector without a filter configured to transmit only in the visible wavelength range. Thus, the manufacture of the glass element 1 may be simplified. The light detector 10 may include a detector formed by a CMOS sensor and / or a CCD sensor. The light detector 10 may be an imager formed by an array of pixels, each pixel comprising a CMOS sensor or a CCD sensor. In practice, the light detector mentioned above makes it possible to detect light beams having visible and near infrared wavelengths.

[0048] The glass element 1 may include a housing 14 configured to support a rearview mirror of a vehicle. The housing 14 is fixedly mounted to the first face F4. The light detector 10 may be arranged in the housing 14. Thus, a light beam passing through the set of points of the first face F4 may be detected during use of the vehicle without visually obstructing the driver. Patterned light absorbing layer 15

[0049] refer to Figure 3 and Figure 4, the glass unit 2 may include a light absorbing layer 15. The light absorbing layer 15 may be arranged on a portion of the first face F4, and preferably on at least a portion of the detection surface 11. The light absorbing layer 15 is patterned on the first face F4, and preferably on the detection surface 11.

[0050] For a light beam having a wavelength between 380 nm (inclusive) and 780 nm (inclusive), the light absorbing layer 15 has a transmittance greater than 0.7, and preferably greater than 0.9.

[0051] For a light beam having a wavelength between 780 nm (exclusive) and 2500 nm (inclusive), the light absorbing layer 15 has a transmittance of less than 0.3, and preferably less than 0.1.

[0052] Thus, changes in the spatial distribution of the light intensity along the pattern border can be detected without obstructing the driver's view through the glass unit 2. In fact, the formation of condensation droplets 7 on the pattern border causes the light beam 9 to be scattered and thus causes a change in the spatial distribution of the light intensity detected along this border. This makes it possible to detect the nucleation of condensation droplets 7 with a detection limit that is less than the detection limit of prior art detectors. The light detector 10 may be an imager configured to image the light intensity of the pattern.

[0053] The pattern may include portions having a width of less than 1 cm, preferably less than 5 mm relative to the main surface. Thus, multiple boundaries of the pattern can be imaged during the formation of a single condensation droplet 7, which makes it possible to minimize the detection boundaries of the condensation droplet 7 of the glass element 1.

[0054] refer to Figure 3 and Figure 4 , the pattern may form a strip array on the detection surface 11. The strips may be parallel to each other. Therefore, the boundary for detecting the nucleation of the condensation droplets 7 may be minimized over the entire detection surface 11 covered by the strip array.

[0055] Figure 4 A light absorbing layer 15 forming an array of stripes on the first surface F4 is shown, as well as a region of interest 17 comprising a portion of the array of stripes. Figure 5 The intensity measured by the light detector 10 along a segment through the region of interest 17 is shown in the absence of condensation droplets 7 in the region of interest 17 . Figure 6 The intensity measured by the light detector 10 along a segment through the region of interest 17 is shown in the presence of condensation droplets 7 in the region of interest 17 .

[0056] The light absorbing layer 15 may be formed of a second material. The second material may be a conductive and / or semi-conductive oxide. The second material may be indium tin oxide. Therefore, the second material may have the transmission characteristics of the light absorbing layer 15.

[0057] refer to Figure 7 , the second material may be indium tin oxide doped with at least one metal element and configured to have maximum light absorption for a wavelength between 780 nm and 1000 nm. In fact, doping indium tin oxide with a metal element makes it possible to adjust the wavelength for which light absorption is maximum within the wavelength range between 780 nm and 1000 nm. The morphology of the grains forming the light absorbing layer 15 also makes it possible to adjust the wavelength for which light absorption is maximum within the wavelength range between 780 nm and 1000 nm. Figure 7 The curves a), b), c), d), and e) shown in FIG. 1 correspond to the light absorbing layer 15 formed of indium tin oxide, and the morphologies of the crystal grains forming the light absorbing layer 15 are different from each other. The light absorbing layer 15 may be deposited by sputtering.

Claims

1. A glass element (1) for a vehicle, comprising a glass unit (2) extending along a main surface (3), the glass unit (2) comprising a first glass sheet (4), the first glass sheet (4) having a first face (F4) parallel to the main surface (3) and a second face (F3), the second face (F3) being opposite to the first face (F4) with respect to the first glass sheet (4), the glass unit (2) having a first edge (5) and a second edge (6) opposite to the first edge (5), the first face (F4) being able to come into contact with the interior environment of the vehicle and being able to support the nucleation of condensation droplets (7), The glass element (1) is characterized in that: the glass element (1) comprises a light source (8) configured to emit a light beam (9) and a light detector (10) configured to detect the light beam (9) emitted by the light source (8), the light source (8) being arranged so that the light beam (9) propagates in the first glass sheet (4) from the first edge (5) to the second edge (6) by means of several total internal reflections on the first face (F4) and the second face (F3), The light detector (10) is arranged outside the glass unit (2) and on the side of the first face (F4) relative to the first glass sheet (4), The first face (F4) comprises a detection surface (11), the detection surface (11) having a surface area greater than 0.01%, inclusive, of the total surface area of ​​the first face (F4), The light detector (10) is configured to receive at least part of the light beam (9) passing through the detection surface (11).

2. The glass element (1) according to claim 1, wherein The glass unit (2) is a laminated glass unit, the glass unit (2) comprising a second glass sheet (12) and an interlayer (13) arranged between the first glass sheet (4) and the second glass sheet (12), the second surface (F3) being on a side of the interlayer (13) relative to the first glass sheet (4), the first glass sheet (4) being formed of a first glass having a first refractive index n1, the glass unit (2) comprising a first material, the first material covering the second surface (F3) on a side of the interlayer (13) relative to the second surface (F3) and having a second refractive index n2, the second refractive index n2 being strictly smaller than the first refractive index n1.

3. The glass element (1) according to claim 2, wherein: The first material covering the second face (F3) at least partially forms the interlayer (13).

4. The glass element (1) according to claim 2 or 3, wherein: The first glass has a first absorption coefficient a1 of the light beam (9), the second glass sheet (12) is formed of a second glass, the second glass has a second absorption coefficient a2 of the light beam (9), the first absorption coefficient a1 is strictly smaller than the second absorption coefficient a2, and the first absorption coefficient a1 is preferably smaller than 0.5 cm -1 , especially less than 0.1cm -1 .

5. The glass element (1) according to any one of claims 1 to 4, wherein: The light source (8) extends along the first edge (5), preferably from one corner of the glass unit (2), in particular to another corner of the glass unit (2).

6. The glass element (1) according to any one of claims 1 to 5, wherein: The light beam (9) has a wavelength between 780 nm and 2500 nm, inclusive.

7. The glass element (1) according to any one of claims 1 to 6, wherein: The detection surface (11) is defined by a portion of the first face (F4), the portion extending along an element selected from: a lateral edge of the glass unit (2), a lateral edge of the glass unit (2) on the driver's side, a lower lateral edge of the glass unit (2), a corner of the glass unit (2) and a lower corner of the glass unit (2) on the driver's side.

8. The glass element (1) according to any one of claims 1 to 7, wherein: The photodetector (10) is free of a filter configured to transmit a light beam having a wavelength only between 380 nm and 780 nm, inclusive.

9. The glass element (1) according to any one of claims 1 to 8, wherein: The light detector (10) has a field of view, and the arrangement of the light detector (10) and the field of view is configured such that the light detector (10) detects a light beam passing through the detection surface (11).

10. The glass element (1) according to any one of claims 1 to 9, wherein: The first edge (5) is the lateral edge of the glass unit (2) on the driver's side.

11. The glass element (1) according to any one of claims 1 to 10, comprising a housing (14) configured to support a rearview mirror of the vehicle, the light detector (10) being arranged in the housing (14).

12. The glass element (1) according to any one of claims 1 to 11, wherein: The glass unit (2) comprises a light absorbing layer (15) arranged on a portion of the first face (F4), the light absorbing layer (15) forming a pattern on the first face (F4), the light absorbing layer (15) having a transmittance greater than 0.7, preferably greater than 0.9 for a wavelength range between 380 nm and 780 nm, the wavelength range being inclusive of 380 nm and 780 nm, and having a transmittance less than 0.3, preferably less than 0.1 for a wavelength range between 780 nm and 1100 nm, the wavelength range being exclusive of 780 nm and inclusive of 1100 nm.

13. The glass element (1) according to claim 12, wherein: The light absorbing layer (15) is formed of a second material, which is a conductive and / or semi-conductive oxide, and the second material is preferably indium tin oxide.

14. The glass element (1) according to claim 12 or 13, wherein: Portions of the pattern have a width relative to the major surface that is less than 1 cm.

15. The glass element (1) according to any one of claims 12 to 14, wherein: The pattern forms an array of stripes on the detection surface (11), the stripes preferably being parallel to each other.

16. The glass element (1) according to any one of claims 13 to 15, wherein: The second material is indium tin oxide doped with at least one metal element and is configured to have maximum light absorption for a wavelength between 780 nm and 1000 nm.

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