VEHICULAR CABIN MONITORING SYSTEM WITH CAMERA AT INTERIOR REARVIEW MIRROR ASSEMBLY

A vehicular cabin monitoring system includes an interior rearview mirror assembly having a mirror head that accommodates a prismatic mirror reflective element and a camera. The prismatic mirror reflective element is adhesively attached at a mirror back plate of the mirror head. A not-optically-clear adhesive (NOCA) layer is disposed between a mirror reflector coating at a rear side of the prismatic mirror reflective element and the mirror back plate. The camera views through (i) the NOCA layer, (ii) the mirror reflector coating and (iii) the glass substrate of the prismatic mirror reflective element. Electronic circuitry of an electronic control unit (ECU) includes an image processor for processing image data captured by the camera. With the mirror assembly mounted at an interior portion of a vehicle, image data captured by the camera is processed at the ECU for an occupant monitoring function or a driver monitoring function.

FIELD OF THE INVENTION

The present invention relates generally to the field of interior rearview mirror assemblies for vehicles.

BACKGROUND OF THE INVENTION

It is known to provide a mirror assembly that is adjustably mounted to an interior portion of a vehicle, such as via a single or double ball pivot or joint mounting configuration where the mirror casing and reflective element are adjusted relative to the interior portion of a vehicle by pivotal movement about the single or double ball pivot configuration. The mirror casing and reflective element are pivotable about either or both of the ball pivot joints by a user that is adjusting a rearward field of view of the reflective element.

SUMMARY OF THE INVENTION

A cabin monitoring system or driving assistance system or vision system or imaging system for a vehicle utilizes one or more cameras (preferably one or more CMOS cameras) to capture image data. The system may include a mirror head adjustably attached at a mounting structure or base. The mounting structure is configured to attach at an interior portion of a vehicle. The mirror head includes a prismatic mirror reflective element. A camera is accommodated by the mirror head. The prismatic mirror reflective element includes a wedge-shaped glass substrate and a mirror reflective coating disposed at a rear side of the wedge-shaped glass substrate. The prismatic mirror reflective element is adhesively attached at a mirror back plate of the mirror head. A not optically clear adhesive (NOCA) layer is disposed between the mirror reflector coating of the prismatic mirror reflective element and the mirror back plate. The camera views through the NOCA layer, the mirror reflector coating of the prismatic mirror reflective element and the glass substrate of the prismatic mirror reflector element. An electronic control unit (ECU) comprises electronic circuitry and associated software, and the electronic circuitry of the ECU comprises an image processor for processing image data captured by the camera. With the mounting structure attached at the interior portion of the vehicle, image data captured by the camera is processed at the ECU for an occupant monitoring function or a driver monitoring function.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and the illustrative embodiments depicted therein, an interior rearview mirror assembly10for a vehicle includes a casing12and a reflective element14positioned at a front portion of the casing12(FIG.1). In the illustrated embodiment, the mirror assembly10is configured to be adjustably mounted to an interior portion of an interior cabin of a vehicle (such as to an interior or in-cabin surface of a vehicle windshield or a headliner of a vehicle or the like) via a mounting structure or mounting configuration or assembly16. The mirror reflective element14may comprise a prismatic mirror reflective element that comprises a wedge-shaped glass substrate that can be flipped between a daytime orientation and a nighttime or anti-glare orientation. The system may include a camera18disposed behind the mirror reflective element14and viewing through the mirror reflective element for capturing image data representative of the interior cabin of the vehicle, including the driver's head region and occupant region of the vehicle cabin. The system may utilize aspects of the driver monitoring systems or occupant monitoring systems described in U.S. Pat. Nos. 11,930,264; 11,827,153; 11,780,372 and/or 11,639,134 and/or International Publication No. WO 2023/220222, which are all hereby incorporated herein by reference in their entireties.

The mirror assembly10includes or is associated with a driver monitoring system (DMS) and/or an occupant monitoring system (OMS), with the mirror assembly comprising the driver/occupant monitoring camera18disposed at a back plate20(and viewing through an aperture of the back plate) behind the reflective element14and viewing through the reflective element toward at least a head region of the driver of the vehicle (FIG.2). The DMS may include one or more infrared (IR) or near infrared (NIR) light emitter(s)22, which may be disposed at the back plate20and may emit light through another aperture of the back plate and through the reflective element.

Referring toFIG.3, the prismatic mirror reflective element14may include a wedge-shaped glass substrate26with a mirror reflector coating28configured to provide reflections for the driver to view rearward via the mirror assembly10. With the mirror assembly attached at the interior portion of the vehicle cabin and a front surface of the glass substrate26facing the driver of the vehicle and the cabin of the vehicle, the mirror reflector coating28is disposed at an opposite rear surface of the glass substrate26. The mirror reflector coating28may include a multi-layer coating stack. Further, an optically clear adhesive (OCA)30and neutral density (ND) filter32may be disposed between the mirror reflector coating28and a foam tape or adhesive element34at the rear surface of the glass substrate26. The foam tape34is configured to adhesively attach the mirror reflective element14at the mirror back plate20. A protective liner36may be disposed at a rear surface of the foam tape34and removable from the foam tape34to attach the foam tape34and the mirror reflective element14at the mirror back plate20. With the mirror reflective element14attached at the mirror back plate20, the camera18views through the aperture in the mirror back plate20and may view through an aperture in the foam tape34.

An example method of manufacturing the prismatic mirror reflective element14may include coating flat glass sheets with the multi-layer reflective coating28. The coated flat glass sheets may then be cut into strips and the coated flat glass strips may be beveled. The coated beveled glass strips may be laser cut to shape to form the wedge-shaped glass substrate26. The OCA30and the ND filter32may be laminated together and de-bubbled. Further, the OCA30and ND filter32may be die-cut to shape and the die-cut OCA30and ND filter32may be laminated to the coated beveled glass shapes (i.e., the wedge-shaped glass substrate26with the mirror reflective coating28). The glass sub-assembly (i.e., the glass substrate26, mirror reflective coating28, OCA30, and ND filter32) may then be de-bubbled and a die-cut foam tape34may be adhered to the glass sub-assembly. The mirror reflective element14may include characteristics of the prismatic mirror reflective elements described in U.S. Publication No. US-2024-0075878, which is hereby incorporated herein by reference in its entirety.

One or more portions of the example manufacturing method may be prone to quality issues. For example, point marks may form on the ND filter32(FIG.4) and surface roughness or orange skin may form on the laminated assembly (FIG.5). Thus, and as shown inFIG.6, quality of image data captured by the camera viewing through the mirror reflective element may be reduced by the point marks or roughened surface. That is, the surface quality issues may cause distortion or occlusion of the image data and therefore reduce the image quality or sharpness of the DMS camera.

Referring toFIGS.7-10, combining a visible light absorption dye138and an ultraviolet (UV) curable liquid OCA (LOCA)140may provide a UV curable not-optically-clear adhesive (NOCA)142for application at a prismatic glass substrate to provide a mirror reflective element that reduces or eliminates quality issues. That is, a mirror reflective element with a layer of UV curable NOCA142may improve the quality of image data captured by the DMS camera viewing through the mirror reflective element. Further, use of the UV curable NOCA142may result in cost savings for the mirror reflective element. The layer of UV curable NOCA142may be disposed between the multi-layer mirror reflector coating and the foam tape.

The visible light absorption dye138is combined with the UV curable LOCA140to reduce transmission of visible light incident at the UV curable NOCA142. For example, the layer of UV curable NOCA142may yield visible light transmission of about 50 percent or less, 30 percent or less, 25 percent or less, 20 percent or less, and the like. Transmission of IR and NIR light may not be affected by the UV curable NOCA142. For example, the NOCA may transmit at least 60 percent of near-infrared light incident at the reflective element, such as at least 80 percent of near-infrared light incident at the reflective element, such as at least 90 percent of near-infrared light incident at the reflective element. The glass and the mirror reflector coating of the mirror reflective element may have a collective visible light transmission rate of about 50 percent or less. Thus, with the layer of NOCA142disposed at the mirror reflective element, the glass, the mirror reflector coating and the NOCA142may have a collective or full system visible light transmission rate of less than 30 percent, such as between about 20 percent and 30 percent, such as, for example, about 25 percent full system visible light transmission. In other words, between about 20 percent and 30 percent of visible light incident at the mirror reflective element may pass through the glass substrate, the mirror reflector coating, and the layer of NOCA142. The glass and mirror reflector coating and NOCA may transmit at least 60 percent of near-infrared light incident at the reflective element, such as at least 80 percent of near-infrared light incident at the reflective element, such as at least 90 percent of near-infrared light incident at the reflective element.

Further, the visible light absorption dye138acts as a dye rather than a pigment and thus has 100 percent solubility with the UV curable LOCA140. The visible light absorption dye138is a cost efficient solution. For example, the visible light absorption dye138may include a powder, such as DT19-29A commercially available from Epolin, LLC of Newark, New Jersey.

The UV curable LOCA140provides an index of refraction that may be similar to acrylic, such as an index of refraction of about 1.47. The UV curable LOCA140cures when exposed to UV light without distortion, waviness or tack. Further, the UV curable LOCA140has a relatively low viscosity and is a cost efficient solution. For example, the UV curable LOCA140may include UV curable LOCAs commercially available from Henkel AG & Co. KGaA of Düsseldorf, Germany or Panacol-USA Inc. of Torrington, Connecticut.

FIG.8includes the mirror reflective element14(with OCA and ND filter) and a plurality of glass samples that include different configurations of the UV curable NOCA142. For example, a first glass sample114amay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140. A second glass sample114bmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140, at a thickness of about 250 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.1 percent. A third glass sample114cmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140, at a thickness of about 500 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.1 percent. A fourth glass sample114dmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140, at a thickness of about 250 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.2 percent.

As shown inFIG.9, a fifth glass sample114emay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140 VLV. A sixth glass sample114fmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140 VLV, at a thickness of about 250 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.1 percent. A seventh glass sample114gmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140 VLV, at a thickness of about 500 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.1 percent. An eighth glass sample114hmay include a flat glass sheet having a thickness of about 3.2 millimeters with a multi-layer mirror reflective coating and a UV curable NOCA142that includes a UV curable LOCA140, such as Panacol VITRALIT® 5140 VLV, at a thickness of about 100 micrometers and a light absorption dye138, such as Epolin DT19-29A, at a concentration of about 0.25 percent.

FIG.10depicts a graph1000that compares the transmittance of the glass samples for different wavelengths of light in the visible spectrum and in the IR and the NIR spectrum. For example, line1000amay separate visible light wavelengths and NIR and IR light wavelengths in the graph1000at a wavelength of about 700 nanometers. The visible light spectrum may be measured at wavelengths between about 400 nanometers and 700 nanometers. The NIR and IR light spectrum may be measured at wavelengths greater than about 700 nanometers, such as between about 800 nanometers and 1,000 nanometers. Further, a target transmittance for visible light incident at the mirror reflective element may be between about 20 percent and 30 percent transmittance so that the mirror reflective element having the UV curable NOCA142provides for visible light transmittance of between about 20 percent and 30 percent while providing for NIR or IR light transmittance of 20 percent or more, 50 percent or more, 70 percent or more, 90 percent or more and the like. As shown a preferred thickness and die concentration for the UV curable NOCA142may include a thickness of about 250 micrometers and a dye concentration of about 0.1 percent, such as included in the second glass sample114bor the sixth glass sample114f, or a thickness of about 100 micrometers and a dye concentration of about 0.25 percent, such as included in the eighth glass sample114h. In other words, the composition of the layer of NOCA142at the mirror reflective element may be configured such that the mirror reflective element allows between about 20 percent and 30 percent of visible light incident at the mirror reflective element to pass through the mirror reflective element, and the composition of the layer of NOCA142may be configured to achieve the target transmission rate throughout the visible light spectrum.

An example method of manufacturing a prismatic mirror reflective element with a layer of UV curable NOCA142may include coating flat glass sheets with the multi-layer reflective coating. The coated flat glass sheets may then be cut into strips and the coated flat glass strips may be beveled. The layer of UV curable NOCA142may be sprayed or flooded onto the coated beveled glass strips and then cut, such as laser cut, to form the wedge-shape of the glass substrate. The wedge-shaped glass substrates, that have been laser cut, coated with the multi-layer reflective coating, beveled, and sprayed or flooded with the layer of UV curable NOCA142may be broken from the strip. For example, the glass substrates may be manually broken from the strip by an operator. Further, the die cut foam tape is adhered to the glass sub-assembly.

Thus, the prismatic glass substrate may include a multi-layer mirror reflector coating at a rear surface of a wedge-shaped glass substrate. The layer of UV curable NOCA142is applied between mirror reflector coating and the foam tape, such as to hide or render covert the foam tape and one or more electronic components within the mirror head, such as the DMS camera and the light emitter. The DMS camera views through the layer of UV curable NOCA142and the mirror reflective element, and the layer of UV curable NOCA142reduces quality issues in the mirror reflective element such that quality of image data captured by the DMS camera is improved. For example, fewer occlusions or distortions are present in the captured image data.

The prismatic mirror assembly may be mounted or attached at an interior portion of a vehicle (such as at an interior surface of a vehicle windshield) via the mounting means described above, and the reflective element may be toggled or flipped or adjusted between its daytime reflectivity position and its nighttime reflectivity position via any suitable toggle means, such as by utilizing aspects of the mirror assemblies described in U.S. Pat. Nos. 6,318,870 and/or 7,249,860, and/or U.S. Publication No. US-2010-0085653, which are hereby incorporated herein by reference in their entireties. Optionally, for example, the interior rearview mirror assembly may comprise a prismatic mirror assembly, such as the types described in U.S. Pat. Nos. 7,289,037; 7,249,860; 6,318,870; 6,598,980; 5,327,288; 4,948,242; 4,826,289; 4,436,371 and/or 4,435,042, which are hereby incorporated herein by reference in their entireties. Optionally, the prismatic reflective element may comprise a conventional prismatic reflective element or prism or may comprise a prismatic reflective element of the types described in U.S. Pat. Nos. 7,420,756; 7,289,037; 7,274,501; 7,249,860; 7,338,177 and/or 7,255,451, which are all hereby incorporated herein by reference in their entireties.