Patent Description:
<CIT> discloses a mirror assembly having a mirror element which comprises reflective metallic layer sandwiched between a respective pair of transparent non-metallic layers. The layers are configured such that the reflective element is selectively spectrally tuned to transmit at least one preselected spectral band of radiant energy therethrough while reflecting other radiant energy.

<CIT> discloses a semipermeable mirror element for an inner rear mirror of a vehicle. The semipermeable mirror element has an iris-detection unit fixed to a rear side of the mirror element, wherein the iris-detection unit detects an iris of a driver through the element. The detection unit is arranged in a centre of the element.

The invention is defined by the features disclosed in the independent claim.

According to the claimed invention, electrochromic rearview mirror system for an automotive vehicle is disclosed. The system comprises an electrochromic element comprising a first substrate comprising a first surface and a second surface. The electrochromic element further comprises a second substrate comprising a third surface and a fourth surface, wherein the first substrate and the second substrate form a cavity between the second surface and the third surface. An electrochromic medium is contained in the cavity. A transflective dielectric coating is disposed at the fourth surface. The system further comprises an image sensor directed toward the fourth surface of the electrochromic element. The image sensor comprises an emitter configured to emit light in a NIR range.

The transflective dielectric coating may comprise a multi-layer stack comprising alternating high-index (H) and low-index (L) materials.

These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.

For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," and derivatives thereof shall relate to the invention as oriented in <FIG>. Unless stated otherwise, the term "front" shall refer to the surface of the element closer to an intended viewer of the mirror element, and the term "rear" shall refer to the surface of the element further from the intended viewer of the mirror element. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary.

The terms "including," "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a. " does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

Referring to <FIG>, the disclosure may provide for a scanning apparatus <NUM> operable to perform an identification function. In the claimed invention, the scanning apparatus <NUM> is incorporated in a rearview mirror assembly <NUM> comprising an electro-optic assembly <NUM> for an automotive vehicle. The electro-optic assembly <NUM> comprises an electrochromic (EC) mirror. In this configuration, the electro-optic assembly <NUM> is an electrochromic mirror element which can vary in reflectivity in response to a control signal from a control. The control signal may change an electrical potential supplied to the electro-optic assembly <NUM> to control the reflectivity.

The scanning apparatus <NUM> may be configured to process and/or control an identification function. The identification function may comprise an eye-scan or retinal identification function. In the claimed invention, the scanning apparatus <NUM> provides for the interior rearview mirror assembly <NUM> to be configured to identify an operator or passenger of a vehicle based on the eye-scan identification function. The identification function may be processed by the controller and/or communicated from the controller to one or more vehicle systems to provide for an identification of the operator or passenger of the vehicle.

The eye-scan-identification function utilizes an infrared illumination of an iris of an eye for the identification. The illumination of the eye(s) may be optimized in conditions allowing for a high optical transmittance in the near infrared (NIR) range. Accordingly, the disclosure provides for an electrochromic (EC) stack of the electro-optic assembly that may have a high light transmittance in wavelengths ranging from about <NUM> to <NUM> in the optical spectrum. Additionally, the electro-optic assembly comprises a plurality of light sources configured to illuminate at least one iris of the operator of the vehicle.

To provide for the eye-scan-identification function, for example an iris or retinal scan, an image sensor <NUM> is disposed proximate a rear surface of the electro-optic assembly. The image sensor <NUM> may correspond to, for example, a digital charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) active pixel sensor, although not be limited to these exemplary devices. The image sensor <NUM> is in communication with light sources <NUM>, to infrared emitters configured to output an emission <NUM> of light in the NIR range. In the claimed invention, the image sensor <NUM> is configured to selectively activate one or more infrared emitters corresponding to the light sources <NUM> to illuminate the iris such that an identity of an operator <NUM> of the vehicle may be determined.

The infrared emitters or the light sources <NUM> may correspond to a plurality of infrared emitter banks. Each of the infrared emitter banks may comprise a plurality of light emitting diodes, which may be grouped in a matrix or otherwise grouped and disposed behind a rear surface of the electro-optic device. In an exemplary embodiment, the plurality of light sources <NUM> may correspond to a first emitter bank <NUM> and a second emitter bank <NUM>. The first emitter bank <NUM> may be configured to output the emission in the NIR range from a first side portion <NUM> of a front surface <NUM> of the electro-optic assembly <NUM>. The second emitter bank <NUM> may be configured to output the emission in the NIR range from a second side portion <NUM> of the front surface <NUM> of the electro-optic assembly <NUM>, which may comprise a mirror element <NUM> of the mirror assembly <NUM>. In this configuration, the scanning apparatus <NUM> may be configured to illuminate the eyes of the operator <NUM> such that the image sensor <NUM> may capture an image of the irises of the eyes.

In an exemplary embodiment, each of the first emitter bank <NUM> and/or the second emitter bank <NUM> may correspond to more or fewer LEDs or banks of LEDs. In some embodiments comprising an electro-optic assembly having a high level of transmittance in the NIR range, the scanning apparatus <NUM> may utilize fewer or less intense LEDs. Electro-optic assemblies having a high level of transmittance in the NIR range may correspond to assemblies comprising a transflective dielectric coating disposed on a fourth surface of the electro-optic assembly.

In some embodiments comprising an electro-optic assembly having a lower level of transmittance in the NIR range, the scanning apparatus <NUM> may utilize a greater number of or more intense LEDs. Electro-optic assemblies having a lower level of transmittance in the NIR range may correspond to assemblies comprising a metal-based, transflective coating disposed on a third surface of the electro-optic assembly. Further details of the electro-optic assembly are discussed in reference to <FIG> and <FIG>.

The image sensor <NUM> may be disposed on a circuit <NUM>, for example a printed circuit board in communication with a controller. The controller may further be in communication with various devices that may be incorporated in the vehicle via the communication bus or any other suitable communication interface. The controller may correspond to one of more processors or circuits, which may be configured to process image data received from the image sensor <NUM>. In this configuration, the image data may be communicated from the image sensor <NUM> to the controller. The controller may process the image data with one or more algorithms configured to determine an identity of the operator of the vehicle.

The controller may further be in communication with a display <NUM>. The display <NUM> may be disposed in the mirror assembly <NUM> behind the rear surface. The controller may be operable to display the image data received from the image sensor <NUM> such that the operator may view the image data. In this configuration, the operator <NUM> may adjust a position of the eyes shown on the display <NUM> to position the eyes such that the image data may include the necessary features required to identify the operator. In an exemplary embodiment, the features required to identify the operator of the vehicle may correspond to features of the eyes of the operator <NUM> (e.g. the irises).

The display <NUM> may correspond to a partial or full display mirror configured to display an image data through at least a portion of the mirror assembly <NUM>. The display <NUM> may be constructed utilizing various technologies, for example LCD, LED, OLED, plasma, DLP or other display technology. Examples of display assemblies that may be utilized with the disclosure may include <CIT> "Rearview display mirror," <CIT> entitled "Vehicular rearview mirror assembly <NUM> including integrated backlighting for a liquid crystal display (LCD)," <NUM>,<NUM>,<NUM> "Multi-display mirror system and method for expanded view around a vehicle," and <NUM>,<NUM>,<NUM> "Vehicle rearview mirror assembly <NUM> including a high intensity display".

The scanning apparatus <NUM> may further comprise an indicator <NUM> in the mirror assembly <NUM>. The indicator <NUM> may be in communication with the controller and configured to output a signal to identify a state of the scanning apparatus <NUM> and/or a rearview camera as discussed in reference to <FIG>. The indicator may correspond to a light source that may be operable to flash and/or change colors to communicate a state of the scanning apparatus <NUM>. The indicator <NUM> may correspond to a light emitting diode (LED), and in an exemplary embodiment, the indicator <NUM> may correspond to a red, green, and blue (RGB) LED operable to identify the state of the scanning apparatus <NUM> by outputting one of more colored emissions of light.

Referring to <FIG>, a cross-sectional view of a mirror assembly <NUM> is shown. The electro-optic assembly <NUM> is partially reflective and partially transmissive and comprises the mirror element <NUM>. The mirror element <NUM> includes a first substrate <NUM> having a first surface 42a and a second surface 42b. The mirror element <NUM> further comprises a second substrate <NUM> having a third surface 44a and a fourth surface 44b. The first substrate <NUM> and the second substrate <NUM> define a cavity <NUM> and may be substantially parallel. The first surface 42a and the third surface 44a may be oriented toward the front surface <NUM> of the mirror assembly <NUM>. The second surface 42b and the fourth surface 44b may be oriented toward a rear surface of the mirror assembly <NUM>.

The cavity <NUM> contains an electrochromic medium. The cavity <NUM> may be completely or partially filled with the medium <NUM>. The mirror assembly <NUM> may be in communication with a dimming controller via electrical contacts and may comprise various seals to retain the medium <NUM> in the cavity <NUM>. In this configuration, the mirror assembly <NUM> may be configured to vary in reflectance in response to a control signal received from the dimming controller via the electrical contacts.

Each of the surfaces 42a, 42b, 44a, and 44b corresponds to interfaces of the mirror assembly <NUM>. The first surface 42a corresponds to a first interface <NUM>. The second surface 42b corresponds to a second interface <NUM>. The third surface 44a corresponds to a third interface <NUM>, and the fourth surface 44b corresponds to a fourth interface <NUM>. In a conventional electro-optic assembly, a transflective coating <NUM> may typically be disposed on the third interface <NUM>. The transflective coating may typically comprise a layer containing silver along with additional layers such as metal, dielectric and/or transparent conducting oxides located above or below the silver comprising layer or both. As shown in Table <NUM>, the electrochromic element with a transflective coating <NUM> may generally have a nominal reflectance of <NUM>% and a nominal transmittance of <NUM>% in the visible range. The visible reflectance and transmittance may vary depending on design considerations and design objectives. However, in the NIR range, the transmittance will typically be less than the transmittance in the visible spectrum and may be less than <NUM>% as illustrated in <FIG>. The relatively low transmittance in the NIR range may be due to the thickness and optical constants of materials comprising the metal-based, transflective coating.

The metal-based, transflective coating <NUM> may inhibit the light source <NUM> and reduce the intensity of the energy of the light source <NUM> reaching the subject if the light source is configured in the mirror assembly <NUM> rearward of, and transmitting through, the electrochromic element. Additionally, the metal-based, transflective coating <NUM> may inhibit a returning signal to be captured by a receiver of the image sensor <NUM> if it is also configured to be rearward of the transflective electrochromic element. Maintaining a neutral color in the reflected and transmitted spectrums of the image sensor <NUM> requires precise engineering of the coating materials and thicknesses on each of the interfaces <NUM>-<NUM>. Such precision prevents color bias of the mirror and devices, such as the image sensor <NUM>, configured rearward of the electrochromic element.

Referring now to <FIG>, the transflective coating is impiemented as a transflective dielectric coating <NUM> that is applied to the fourth interface <NUM>. The transflective dielectric coating <NUM> is used to replace the metal-based, transflective coating <NUM> as demonstrated in <FIG>. Transflective dielectric coating <NUM> is designed to resolve the issues related to the limited transmission in the NIR range for the mirror assembly <NUM> and provide NIR transmittance greater than about <NUM>%. The dielectric coating <NUM> is designed to attain a reflectance level comparable to industry standard, i.e., about <NUM>% to <NUM>%, or about <NUM>% to <NUM>%, or about <NUM>% to <NUM>%. Additionally, the dielectric coating can be designed to attain a neutral color appearance in the visible color range for normal incidence viewing angle up to broad viewing angles. In this way, the disclosure provides for improved transmittance in the NIR range while maintaining visible color performance and mirror functionality.

The transflective dielectric coating <NUM> may comprise low-loss dielectric materials configured in an alternating high and low refractive index multi-layer stack. Examples of low-loss dielectric materials include, but are not limited to, niobium oxide, silicon oxide, tantalum oxide, aluminum oxide, etc. Additionally, with the tuning flexibility in an alternating high-index (H) and low-index (L) material multilayer (HL-Stack) construction, the transmittance of the dielectric coating <NUM> in the NIR range can be above <NUM>% in some embodiments. In some embodiments, the NIR transmittance of the dielectric coating <NUM> may be greater than <NUM>%. In an exemplary embodiment, the NIR transmittance of the dielectric coating <NUM> may be greater than <NUM>%. In the claimed invention, the NIR transmittance, for at least some wavelengths between about <NUM> and <NUM>, is greater than the visible transmittance, preferably greater than <NUM> times the visible transmittance and more preferably greater than <NUM> times the visible transmittance.

An example of the dielectric coating <NUM> exhibiting the transmittance in the NIR range greater than <NUM>% is shown in <FIG>. Due to the low electric conductivity of the dielectric materials utilized in the dielectric coating <NUM>, the dielectric coating <NUM> is not ideal for use as transflective electrode on surface <NUM> but may be utilized on the fourth interface <NUM>. The dielectric coating <NUM> may be disposed on the fourth interface <NUM>. On surface <NUM>, an alternate transparent electrode, such as ITO, can be used to maintain the necessary high electric conductivity for the surface <NUM> electrode. The high electrical conductivity is required at the third interface to supply electrical current to the electro-optic medium <NUM> in order for the change in chemical state to occur.

Table <NUM> provides detailed, representative, examples of stack designs of dielectric transflective coatings at the fourth interface <NUM> of the mirror assembly <NUM> that provide appropriate visible transflective properties and enhanced NIR transmittance. In these examples, the high refractive index (H) material is Niobium Oxide and the low refractive index (L) material is Silicon Dioxide. It should be understood that these two examples are not meant to be limiting. Alternate dielectric coatings may have a quantity of layers between <NUM> and <NUM> or more than <NUM> layers. The number of layers needed to achieve the design goals will vary with the selection of the high and low refractive index materials. Fewer layers may be needed as the difference in refractive index between the two materials increases. Conversely, more layers may be needed if the refractive index difference is less. The refractive index difference may be greater than about <NUM>, greater than about <NUM> or greater than about <NUM>. Additional materials may be added which have refractive indices different that the high and low index materials.

A theoretical performance in the visible range of the mirror assembly <NUM> with these example dielectric transflective coatings <NUM> are given in Table <NUM>. The modeled mirror assembly comprises a first piece of <NUM> glass with an ITO layer on surface <NUM> that is approximately <NUM> thick, a second piece of <NUM> glass with an ITO layer on surface <NUM> that is approximately <NUM> thick, a cell spacing (distance between surfaces <NUM> and <NUM>) of about <NUM> microns, a perimeter seal of epoxy to create a chamber between the two pieces of glass and the chamber is filled with a gel based electrochromic media, which is further discussed herein. The dielectric, multi-layer coating is on surface <NUM>. The visible reflectance is maintained at <NUM>-<NUM>% and visible transmittance is <NUM>-<NUM>%. The CIELAB color coordinates a* and b* are maintained as small values (between -<NUM> and <NUM>) for both transmission and reflection spectra of <NUM> and <NUM> layer designs, which indicates good color neutral appearance. When changing the viewing angle, the spectrum usually shifts toward the short wavelength region of the visible spectrum and the different polarization states (electro-magnetic waves oscillating in orthogonal directions) typically react differently. Thus, both contribute to a color biasing of the spectra causing a color change on the appearance of the mirror with changes in view angle.

The disclosure provides for a dielectric coating <NUM> with flat spectra in the visible range as shown in <FIG> and <FIG> for reflectance and transmittance, respectively, which effectively suppresses color biasing resulting in a neutral reflected and transmitted color. As shown in <FIG>, a color performance of a mirror assembly with <NUM>-Layer-Design is demonstrated. The mirror assembly may be capable of achieving neutral color (Ia* |, |b*| < <NUM>) up to a <NUM> degree viewing angle for the transmitted color. The reflected b* color is quite stable with angle while the a* experiences a slightly larger change with angle. As shown in <FIG>, a color performance of a mirror assembly with a <NUM>-Layer-Design is demonstrated. The mirror assembly may be tuned to balance the transmitted color up to a <NUM> degree viewing angle due to an extended flat spectrum. Such color suppressing for transmission spectrum may be critical for an embedded display. The slight green shift on a* of the reflection spectra for both examples is typically unnoticeable. In some coating variants, the a* value and b* value may change at different rates as the viewing angle is increased. The acceptable color shift can be expressed as C* which equals Sqrt(a*<NUM>+b*<NUM>). As the color shifts with angle the C* value may be less than about <NUM>, less than about <NUM>, or less than about <NUM>. This will ensure that the color of the mirror is acceptable. The a* and b* values may shift with angle and the absolute values of the delta a* and delta b* values, for example |a*initial - a*final|, may be less than about <NUM>, less than about <NUM> and less than about <NUM>. The angle at which these conditions are met should be greater than about <NUM> degrees, or greater than about <NUM> degrees or greater than about <NUM> degrees.

The disclosure provides for a dielectric coating <NUM> with acceptable visible properties applied to the fourth interface <NUM> of a mirror assembly <NUM> to provide for improved transmittance in the NIR range. The mirror assembly <NUM> may be utilized in various embodiments that may require high transmittance in the NIR range. In the claimed invention, the mirror assembly <NUM> is utilized with an eye-scan-identification system configured to securely identify an individual. The eye-scan-identification system may benefit from improved transmittance in the near NIR range that is required to illuminate the eye for the identification.

In the claimed invention, the mirror element <NUM> is an electro-chromic element. One non-limiting example of an electro-chromic element is an electrochromic medium, which includes at least one solvent, at least one anodic material, and at least one cathodic material. Typically, both of the anodic and cathodic materials are electroactive and at least one of them is electrochromic. It will be understood that regardless of its ordinary meaning, the term "electroactive" will be defined herein as a material that undergoes a modification in its oxidation state upon exposure to a particular electrical potential difference. Additionally, it will be understood that the term "electrochromic" will be defined herein, regardless of its ordinary meaning, as a material that exhibits a change in its extinction coefficient at one or more wavelengths upon exposure to a particular electrical potential difference. Electrochromic components, as described herein, include materials whose color or opacity are affected by electric current, such that when an electrical current is applied to the material, the color or opacity change from a first phase to a second phase. The electrochromic component may be a single-layer, single-phase component, multi-layer component, or multi-phase component, as described in <CIT> entitled "Electrochromic Layer And Devices Comprising Same," <CIT> entitled "Electrochromic Compounds," <CIT> entitled "Electrochromic Medium Capable Of Producing A Pre-selected Color," <CIT>entitled "Electrochromic Compounds," <CIT>entitled "Electrochromic Media For Producing A Pre-selected Color," <CIT> entitled "Electrochromic System, "<CIT> entitled "Near Infrared-Absorbing Electrochromic Compounds And Devices Comprising Same," <CIT> entitled "Coupled Electrochromic Compounds With Photostable Dication Oxidation States," and <CIT> entitled "Electrochromic Media With Concentration Enhanced Stability, Process For The Preparation Thereof and Use In Electrochromic Devices"; <CIT>, entitled "Electrochromic Device"; and International Patent Application Serial Nos. <CIT> entitled "Electrochromic Polymeric Solid Films, Manufacturing Electrochromic Devices Using Such Solid Films, And Processes For Making Such Solid Films And Devices," <CIT> entitled "Electrochromic Polymer System," and <CIT> entitled "Electrochromic Polymeric Solid Films, Manufacturing Electrochromic Devices Using Such Solid Films, And Processes For Making Such Solid Films And Devices". To provide electric current to the electro-optic assembly <NUM>, electrical elements are provided on opposing sides of the element, to generate an electrical potential therebetween. A J-clip <NUM> is electrically engaged with each electrical element, and element wires extend from the J-clips <NUM> to the primary PCB <NUM>.

The present disclosure may be used with a mounting system such as that described in <CIT>; <CIT>; and <CIT>; <CIT>; <CIT>; and <CIT>; and <CIT>; <CIT>; and <CIT>. Further, the present disclosure may be used with a rearview packaging assembly such as that described in <CIT>; <CIT>; <CIT>; and <CIT>; <CIT>; and <CIT>; and <CIT>. Additionally, it is contemplated that the present disclosure can include a bezel such as that described in <CIT>; <CIT>; and <CIT>.

It will be appreciated that embodiments of the invention described herein may be comprised of one or more conventional processors and unique stored program instructions that control one or more processors to implement, in conjunction with certain non-processor circuits, some, most, or all of the functions of a mirror assembly <NUM>, as described herein. The non-processor circuits may include, but are not limited to signal drivers, clock circuits, power source circuits, and/or user input devices. As such, these functions may be interpreted as steps of a method used in using or constructing a classification system. Thus, the methods and means for these functions have been described herein. Further, it is expected that one of ordinary skill, notwithstanding possibly significant effort and many design choices motivated by, for example, available time, current technology, and economic considerations, when guided by the concepts and principles disclosed herein will be readily capable of generating such software instructions and programs and ICs with minimal experimentation.

It will be understood by one having ordinary skill in the art that construction of the described invention and other components is not limited to any specific material. Other exemplary embodiments of the invention disclosed herein may be formed from a wide variety of materials, unless described otherwise herein.

It is also important to note that the construction and arrangement of the elements of the invention as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present innovations have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the scope of the appended claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements shown as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied. It should be noted that the elements and/or assemblies of the system may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations.

It will be understood that any described processes or steps within described processes may be combined with other disclosed processes or steps to form structures within the scope of the present invention. The exemplary structures and processes disclosed herein are for illustrative purposes and are not to be construed as limiting.

Claim 1:
An electrochromic rearview mirror system for an automotive vehicle, the electrochromic rearview mirror system comprising:
an electrochromic element (<NUM>), the electrochromic element (<NUM>) comprising:
a first substrate (<NUM>) comprising a first surface (42a) and a second surface (42b);
a second substrate (<NUM>) comprising a third surface (44a) and a fourth surface (44b), wherein the first substrate (<NUM>) and the second substrate (<NUM>) form a cavity (<NUM>) between the second surface (42b) and the third surface (44a);
an electrochromic medium (<NUM>) contained in the cavity (<NUM>); and
a transflective dielectric coating (<NUM>) disposed on the fourth surface (44b), wherein a near infrared transmittance exceeds a visible transmittance of the electro-chromic element (<NUM>);
wherein the electrochromic rearview mirror system is configured to identify an operator of the vehicle based on an eye-scan identification function and further comprises a plurality of light sources and an image sensor, wherein the plurality of light sources (<NUM>) correspond to infrared emitters configured to illuminate at least one iris of the operator of the vehicle, wherein the image sensor (<NUM>) is located rearward of the electrochromic element (<NUM>),
wherein the image sensor (<NUM>) is in communication with the plurality of light sources (<NUM>),
wherein the image sensor (<NUM>) is configured to selectively activate one or more of the plurality of light sources (<NUM>).