Window module with integrated electropolymer sun protection

Abstract

Window module (10) for a vehicle (12), comprising: a first glass pane (20) and a second glass pane (22) arranged in a substantially equidistant relationship thereto and separated therefrom by a spacer element (24), the first glass pane (20), the second glass pane (22) and the spacer element (24) defining a closed internal volume (26); an opaque color layer (90) provided adjacent to the periphery of the second glass pane (22) within the interior volume (26); and an electropolymer shading device (50) disposed in the interior volume (26) and configured to selectively obscure the passage of light through the first and second glass panes (20, 22), the electropolymer shading device (50) comprising: a spreadable tinting material (52) configured to selectively advance across the first glass pane (20) in response to a voltage differential applied between the spreadable tinting material (52) and the first glass pane (20); a photovoltaic cell (56) coupled to the second glass pane (22) and disposed within the opaque color layer (90) so as to be bounded but not obscured by the opaque color layer (90), the photovoltaic cell (56) being configured to generate electrical energy upon exposure to light; and a controller (54) configured to receive the generated electrical energy from the photovoltaic cell (56) and selectively apply the voltage difference between the spreadable tinting material (52) and the first glass pane (20).

Description

TECHNICAL FIELDThe present invention relates generally to a window module with integrated electropolymer sunscreen.BACKGROUNDVehicles such as automobiles include windows that allow the occupant to freely view the exterior while preventing environmental influences such as heat, cold, rain, snow, gray scales, etc. from entering the occupant compartment / vehicle interior. On sunny days, infrared radiation may pass through the windows and may heat an otherwise climate regulated vehicle interior. In certain circumstances, it may be desirable for the occupants of the vehicle to block such radiation. One way of blocking infrared radiation has heretofore been to permanently adhere a tint sheet to the window. Although this strategy can effectively block strong infrared radiation on sunny days, it can also result in a obscuring of the view during night times or during operation under poor lighting conditions. Therefore, it may be desirable to have a toning mechanism which can be selectively operated to shield intense radiation during sunny conditions while permitting complete transparency during poor lighting conditions.The publication DE 196 10 268 C2 discloses a winding and unwinding mechanism for a roller blind device. The publication US 2002 / 0 144 831 A1 describes a window for shielding light for the purpose of temperature control within a building. The publication US 2011 / 0 227 751 A1 discloses a sunroof for a vehicle roof. The publication US 2010 / 0 172 007 A1 describes an insulated glazing unit with a controllable radiation transmission. The document DE 196 30 813 A1 discloses a method for producing an electrochromic pane structure.It is an object of the present invention to provide an improved window module for a vehicle and an improved vehicle.SUMMARYThis object is achieved by the subject matter of the independent claims. Advantageous further developments are specified in the dependent claims.A window module for a vehicle comprises a first glass pane and a second glass pane which is located in a substantially parallel arrangement thereto and is separated therefrom by a spacer element. The first glass pane, the second glass pane, and the spacer element define a closed interior volume in which an electropolymer shading device is disposed to selectively obscure the passage of light through the first and second glass panes.The electropolymer shading device includes a spreadable toning material, a photovoltaic cell, and a controller. The spreadable tint material is configured to selectively advance across the first glass pane in response to a voltage differential applied between the tint material and the first glass pane. The photovoltaic cell is coupled to the second glass pane and is configured to generate electrical energy upon irradiation of light; and the controller is configured to receive the generated electrical energy from the photovoltaic cell and selectively apply the voltage difference between the spreadable tint material and the first glass pane.According to the invention, it is provided that the window module comprises an opaque colored layer which is provided adjacent to the periphery of the second glass pane within the inner volume and that the photovoltaic cell is arranged within the opaque colored layer, such that it is delimited by the opaque colored layer but is not shaded.The controller may further include an energy storage device configured to store the electrical energy generated by the photovoltaic cell. In one configuration, the electropolymer shading device may be energy autonomous so that it does not require an external power supply. For example, the photovoltaic cell may be configured to generate a sufficient amount of electrical energy to maintain the spreadable tint material in an advanced state.The spreadable tint material may comprise a conductive layer and the first glass sheet may comprise a conductive coating disposed such that a voltage differential between the conductive layer and the conductive coating causes the spreadable tint material to advance across the first glass sheet. In one configuration, the controller may be configured to advance the spreadable tint material after receiving from the photovoltaic cell an amount of electrical energy that is above a threshold and further when it detects that the vehicle is at a standstill.The spacer may be disposed about the perimeter of the first glass pane, with the photovoltaic cell and controller disposed adjacent the spacer. Moreover, the second glass sheet may have a protruding portion extending beyond the spacer. The protruding portion of the second glass pane may be configured for mounting the window module to the vehicle. The vehicle may, for example, have a frame element comprising a support and the protruding portion may be designed such that it can be fastened to the shelf, such that a planar transition is provided between the frame element and the second glass pane.The above features and advantages, as well as other features and advantages of the present invention, will be more clearly understood from the following detailed description of the best modes for carrying out the invention when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic plan view of a window module disposed within a portion of a vehicle. FIG. 2 is a schematic, partial cross-sectional view of the window module of FIG. 1 taken along line 2- 2. FIG. 3 is a schematic, partial cross-sectional view of the window module of FIG. 2 with the spreadable tint material advancing across a glass pane.DETAILED DESCRIPTIONReferring now to the drawings, wherein like reference numerals are used to identify like or identical components throughout the several views, FIG. 1 schematically illustrates a window module 10 disposed within a portion of a vehicle 12. The window module 10 generally includes a transparent central portion 14 which is generally bounded by an opaque perimeter portion 16. As illustrated in the partial cross-sectional view shown in FIG. 2, the window module 10 may include a first glass pane (i.e., the inner glass pane 20) and a second glass pane (i.e., the outer glass pane 22) that is in a substantially equidistant arrangement therefrom and separated therefrom by a spacer member 24. The spacer 24 may surround the entire perimeter of the window module 10 such that the outer glass pane 22, the inner glass pane 20, and the spacer 24 define an interior volume 26. The inner and outer glass panels 20, 22 may each be sealingly attached to the spacer 24 such that a gas contained within the interior volume 26 is generally isolated from ambient air present outside the module 10. In one configuration, the interior volume 26 may be filled with a dry or inert gas to prevent condensate formation on the interior surfaces of the glass sheets 20, 22.The window module 10 may be configured to seat within an opening 30 of the vehicle 12 and prevent environmental influences such as wind, rain, heat, or cold air from entering the vehicle 12 while transmitting visible light. For example, in an embodiment where the vehicle is an automobile, the opening 30 may be an opening 30 above the parcel shelf of an automobile, an opening 30 in a rear lift gate of a sport utility sport utility vehicle (SUV), crossover vehicle, river tail vehicle, or transporter, or an opening 30 in the roof. In one configuration, the window module 10 may be a roof glazing module used to provide an around view of the exterior environment from the interior of the vehicle 12.To make the vehicle 12 appear to have a smooth, continuous exterior, the entire window module 10 may be inserted into or under the exterior surface 32 of the vehicle 12. For example, the outer glass pane 22 may include a protruding portion that may extend a distance 34 beyond the inner glass pane 20 and may be configured to rest on a shelf 36 formed proximate the opening 30. In one embodiment, the shelf 36 may be formed into a structural portion of the vehicle body, for example, a closed box beam frame member 38 that may extend along the roof line of an automobile between the A-pillar and the C-pillar. The frame element 38 can be formed, for example, by a punching process, wherein a plurality of punched-out "C-channel" elements are connected to one another.The window module 10 may be secured to the vehicle 10 with a suitable adhesive 40 disposed between the outer glass pane 22 and the shelf 36. Alternatively, the window module 10 may be secured to the vehicle using any configuration of bolts, braces, or fasteners. In addition to the adhesive 40, a weather strip 42 may be provided at the joint between the outer glass panel 22 and the vehicle 12 to prevent water from flowing near the glass-vehicle joint or from becoming deposited with dirt. The weather strip 42 may be made of a polymeric material such as vinyl, urethane, latex, silicone, or rubber. Similarly, an aesthetically pleasing trim strip (not shown) may also be provided between the inner glass panel 20 and the vehicle 12 to cover the underlying joint.As generally illustrated in FIG. 2, an electropolymer shading device 50 may be located within the interior volume 26 of the window module 10 that may serve to selectively prevent passage of electromagnetic radiation through the window module 10. For example, the electropolymer shading device 50 may be configured to selectively tint the transmission characteristics of the window module 10 by propagating a light absorbing and / or light reflecting material over one or both of the glass sheets 20, 22. The electropolymer shading device 50 may include a spreadable tint material 52, a controller 54, and one or more photovoltaic cells 56.In Figure 3, it is schematically illustrated how the spreadable tint material 52 is placed in a spread condition adjacent the inner glass sheet 20. The spreadable toning material 52 may consist of an electrically conductive layer 60 and a dielectric layer 62. In one configuration, the electrically conductive layer 60 may be made of a transparent conductive material, such as indium tin oxide and / or tin oxide. Alternatively, the conductive layer 60 may have reflective properties to block or reflect solar radiation. These properties may be provided, for example, by forming the conductive layer 60 from a deposited aluminum or silver material.The dielectric layer 62 of the spreadable toning material 52 can be an elastic material which has electrically insulating properties and can be wound and unwound in a reliable manner over a long service life. Examples of suitable dielectric materials include polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). The spreadable tint material 52 may further include an integral, tinted, and / or colored layer (not shown) by which light absorbing properties may be imparted to the tint material 52. Alternatively, any coloring may be provided separately as a separate layer / film adjacent to tint material 52.The inner glass pane 20 may include a glass substrate 64 and a conductive coating 66 applied to that surface of the substrate 64 that abuts the interior volume 26 and that may be adjacent the spreadable tint material 52. The conductive coating 66 may be made of a transparent conductive material, such as indium tin oxide and / or tin oxide. Thus, the inner glass sheet 20 may appear optically transparent when the spreadable tint material 52 is retracted.If no external or induced forces are present, the spreadable tint material 52 may be arranged in the initial position to wrap around itself towards the edge of the window module 10 (i.e., the spacer 24 generally illustrated in FIG. 2. This movement may be due to material shape memory or an initial setting assumed by the polymeric dielectric layer 62. When a voltage difference is applied between the conductive layers 60, 66 generally illustrated in FIG. 3, the tint material 52 may be drawn toward the adjacent glass sheet 20 via electrostatic forces that cause the tint material 52 to spread across the glass sheet 20.To provide the selective electrostatic actuation, the controller 54 may be electrically coupled to the conductive layer 60 of the tint material 52 via a first electrical lead 68, and may be electrically coupled to the conductive coating 66 of the inner glass panel 20 via a second electrical lead 70. The controller 54 may be configured to apply a voltage difference across the two corresponding conductive layers 60, 66, which may result in the generation of an electrostatic attraction across the dielectric layer 62.The thicknesses of the various layers and the amount of voltage applied to the conductive layers 60, 66 may be selected according to the particulars of the desired applications, including the spreading / retracting speed, reliability, opacity, and available electrical power. In one embodiment, the total thickness 72 of the spreadable tint material 52 may be less than 500 μm, while the thickness of the conductive coating 66 may be less than 5 μm.The controller 54 may be embodied as one or a plurality of digital computers or computing devices, each including a microprocessor or central processing unit (CPU) or a plurality thereof, a read only memory (ROM), a random access memory (RAM), an electrically erasable and programmable read only memory (EEPROM), a high speed clock, an analog / digital (A / D) converter circuit, a digital / analog (D / A) converter circuit, an input / output (I / O) circuit, power electronics / transformers, and / or signal conditioning and buffering electronics. Alternatively, the controller 54 may be embodied as a collection of elemental electrical components such as capacitors, resistors, transistors, relays.The controller 54 may include an I / O channel 80 for signal transmission that provides selective actuation of the electropolymer shading device 50 and / or communication of the state of the shading device 50 from the module 10 to the outside. For example, one or more switches (not shown) may be coupled to the I / O line 80 to allow a user or occupant in the vehicle to selectively spread the tint material 52 across the transparent center region 14 of the window module 10. Alternatively, such a selective actuation signal may also be received from an electrically coupled vehicle control module (not shown).The controller 54 may be electrically coupled to one or more photovoltaic cells 56, which may be configured to provide either a portion or all of the electrical energy needed to operate the electropolymer shading device 50. For example, in one embodiment, photovoltaic cells 56 may provide a sufficient amount of power to maintain tint material 52 in a spread state without any externally supplied electrical energy. In another embodiment, the photovoltaic cells 56 may provide a sufficient amount of power to advance the tint material 52 from a curled state in a spread state without the need for externally supplied electrical energy.As can be appreciated, the photovoltaic cells 56 may convert light to direct current (i.e., may have a "photovoltaic effect"). The photovoltaic cells 56 may be made of, for example, monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, copper indium gallium selenide / sulfide, and / or any other material known to have a photovoltaic effect. As generally illustrated in FIGS. 1 and 2, the one or more photovoltaic cells 56 may be disposed in the interior volume 26 of the window module 10 such that they are adjacent the outer glass pane 22 and are thus capable of receiving light (e.g., solar energy) through the outer glass pane 22. In one configuration, the photovoltaic cells 56 may be laminated to the outer glass pane 22 using a suitable glass lamination process. Although a typical photovoltaic cell 56 may have an output voltage of only less than one volt, multiple cells 56 may be "stacked" in a series arrangement to achieve higher output voltages.The controller may include one or more electrical storage devices 82 configured to store the electrical energy generated by the photovoltaic cells 56. In this way, the electrical storage devices 82 may provide operating energy to the electropolymer shading device 50, such that the shading device 50 may be operated for a period of time even when the cells 56 are not exposed to direct sunlight. Additionally, the electrical storage devices 82 may function as a buffer between the cells 56 and the control / drive circuits used to spread the tint material 52. In this way, the likelihood that any power consumption will adversely affect the photovoltaic power or efficiency of the cells 56 is reduced. The one or more electrical storage devices 82 may include rechargeable batteries, such as lithium ion batteries, nickel metal hydride batteries, or nickel cadmium batteries. Alternatively, the one or more electrical storage devices 82 may include one or more supercapacitors or ultracapacitors, which may be constructed using electrical double layer capacitor technology, for example.The controller 54 may further include one or more DC / DC converters 84 that may be used to step up the voltage of the stored electricity to an operating voltage that may be required to spread the tint material 52. In one configuration, the required operating voltage may be greater than 100 volts while the electrical storage device 82 is capable of providing less than 18 volts output voltage.In a configuration in which the window module 10 is provided as a panel member within the roof of a motor vehicle, the controller 54 may be configured to automatically spread the tint material 52 across the window module 10 when detecting that the vehicle 12 is positioned in direct sunlight. The controller 54 may make this determination by monitoring the voltage provided by the photovoltaic cells 56 and comparing that voltage to a threshold. In an alternative configuration, the controller 54 may automatically spread the tint material 52 only when the vehicle 12 is positioned in direct sunlight and when it receives an indication (via the I / O channel 80) that the engine of the vehicle 12 is either in the deactivated state or when the transmission has been shifted to the "park" position. In this way, tint material 52 may automatically spread and shade the occupant compartment of vehicle 12 when vehicle 12 is parked in, for example, a sunny parking spot.During operation, when a voltage differential is applied between the conductive layer 60 of the tint material 52 and the conductive coating 66 of the glass 20, a small leakage current may flow across the dielectric layer 62 and / or back through the controller 54. This leakage current may represent the effective holding current needed to maintain the tint material 52 in a spread state. For example, the "hold" current required by a 12 volt supply to maintain the tint material 52 in a spread state may be about 160 μA. While such parasitic power consumption does not pose a problem when the vehicle 12 is running and power is constantly being generated, when the vehicle 12 is deactivated, such consumption may drain the vehicle battery over time (or cause the sunshade to retract - which may result in a possible temperature rise in the occupant cabin). The photovoltaic cells 56 are optimally positioned to provide this current load without causing parasitic consumption at a power source of the vehicle 12. Namely, the tint material 52 is only required for tint purposes when the vehicle 12 is in direct sunlight. The presence of this direct sunlight can accordingly enable the photovoltaic cells 56 to always provide the required holding current to the electropolymer shading device 50.It may be advantageous to provide the components of the electropolymer shading device 50 within the interior volume 26 of the window module 10 to shield the sheet-shaped tint material 52 from dust, airborne dirt, chemicals present in the air, and / or moisture, each of which may adversely affect its performance. Additionally, the glass sheets 20, 22 may provide an insulating barrier that may prevent articles from the environment adjacent the window module 10 from contacting any high voltage components. In addition to providing a clean, electrically isolated operating environment for the electropolymer shading device 50, the interior volume 26 itself may improve the thermal resistance (i.e., R-value) of the window module 10.In one configuration, the photovoltaic cells 56, controller, and various electrical connections may be housed within the opaque perimeter portion 16 of the window module 10, as generally shown in FIGS. 1-2. The opaque perimeter portion 16 may include a dark colored tint or color layer 90 applied to the underside of one or both of the glass sheets 20, 22. The opaque perimeter portion 16 may serve to obstruct or obscure the view of the various components from outside the window module 10. Additionally, as shown in FIG. 2, the black paint layer 90 may be used to obscure the view of the adhesive 40 and the frame member 38 (or other support members) that may be used to attach the window module 10 to the vehicle 12. In accordance with the present invention, photovoltaic cells 56 are disposed within black color layer 90 such that they are generally bounded by color layer 90, but are not shaded by color layer 90. In another embodiment not claimed, the photovoltaic cells 56 may be visible as viewed from the opposite side of the outer glass pane 22 and may abut the black paint layer 90 on at least one side.

Claims

A window module (10) for a vehicle (12), comprising: a first glass pane (20) and a second glass pane (22) disposed in a substantially equidistant arrangement therefrom and separated therefrom by a spacer element (24), wherein the first glass pane (20), the second glass pane (22), and the spacer element (24) define a closed interior volume (26); an opaque paint layer (90) provided adjacent the perimeter of the second glass pane (22) within the interior volume (26); and an electropolymer shading device (50) disposed in the interior volume (26) and configured to selectively obscure the passage of light through the first and second glass sheets (20, 22), the electropolymer shading device (50) comprising: a spreadable tint material (52) configured to selectively advance across the first glass sheet (20) in response to a voltage difference applied between the spreadable tint material (52) and the first glass sheet (20); a photovoltaic cell (56) coupled to the second glass sheet (22) and disposed within the opaque color layer (90) so as to be bounded by the opaque color layer (90) but not shaded, the photovoltaic cell (56) being configured to generate electrical energy upon irradiation of light; and a controller (54) configured to receive the generated electrical energy from the photovoltaic cell (56) and selectively apply the voltage difference between the spreadable tint material (52) and the first glass sheet (20).The window module (10) of claim 1, wherein the controller (54) comprises an energy storage device (28) configured to store the electrical energy generated by the photovoltaic cell (56).The window module (10) of claim 1, wherein the spacer (24) is disposed about the perimeter of the first glass pane (20); and wherein the photovoltaic cell (56) and the controller (54) are disposed adjacent the spacer (24).The window module (10) of claim 3, wherein the second glass pane (22) comprises a protruding portion that extends beyond the spacer element (24), and wherein the protruding portion of the second glass pane (22) is configured for attachment of the window module (10) to the vehicle (12).The window module (10) of claim 1, wherein the spreadable tint material (52) comprises a conductive layer (60); wherein the first glass pane (20) comprises a conductive coating (66); and wherein the voltage difference is applied between the conductive layer (60) and the conductive coating (66).The window module (10) of claim 1, wherein the electropolymer shading device (50) is energy autonomous by the electrical energy generated by the photovoltaic cell (56).The window module (10) of claim 1, wherein the controller (54) is configured to advance the spreadable tint material (52) after receiving from the photovoltaic cell (56) an amount of electrical energy that is above a threshold and further when it detects that the vehicle (12) is at a standstill.The window module (10) of claim 1, wherein the photovoltaic cell (56) is configured to generate a sufficient amount of electrical energy to maintain the spreadable tint material (52) in an advanced state.A vehicle (12) comprising: a frame member (38); and a window module (10) according to any one of claims 1 to 8, wherein the window module (10) is configured for attachment to the frame member (38).

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