US20070144938A1

US20070144938A1 - Waterproof remote function actuator with electronic display

Info

Publication number: US20070144938A1
Application number: US11/306,303
Authority: US
Inventors: Frank Buccinna; John Burca
Original assignee: Lear Corp
Current assignee: Lear Corp
Priority date: 2005-12-22
Filing date: 2005-12-22
Publication date: 2007-06-28
Also published as: DE102006056155A1; GB0625020D0; GB2433549B; GB2433549A

Abstract

A waterproof remote function actuator is formed by bonding a clear plastic foil over the body of a plastic housing having an opening for display of componentry. The clear plastic foil creates a chemical and mechanical bond over the entire surface of the housing, including the opening. This eliminates potential water leakage paths around the opening. In alternative arrangements, the clear plastic foil also covers one or more actuator buttons contained within other openings in the plastic housing to prevent water leakage paths between the one or more actuator buttons and the plastic housing.

Description

TECHNICAL FIELD

The present invention relates generally to remote function actuators with electronic displays, and more particularly to waterproof remote function actuators with electronic displays.

BACKGROUND

Remote function actuators are devices used in a wide variety of applications requiring push-button technology and visible screen displays. Non-limiting examples of remote function actuators of this type include key fobs, cellular telephones, garage door openers and the like.
Typically, remote function actuators included a two-piece plastic housing sealed using a molded-in or drop in gasket. The plastic housing has any number of openings that contain a corresponding number of push buttons. A clear lens such as glass or plastic is then coupled within another opening in the housing through which an electronic display may be viewed. Contained within the plastic housing is electronic circuitry, including a printed circuit board, that is electrically coupled to both the push buttons and the electronic display.
In conventional remote function actuators, the clear lens is sealed to the plastic housing by insert-molding a clear plastic layer around the perimeter of the lens. However, given the repetitive expansion and contraction encountered during a water test over a large temperature range, the seal around the perimeter of the lens was compromised, therein providing a leakage point through which the underlying electronic circuitry may be exposed and damaged.
It is therefore desirable to minimize or otherwise eliminate water-sealing issues typically encountered with the present design.

SUMMARY OF THE INVENTION

The present invention provides a method for waterproofing remote function actuator devices that include a window display built therein.
The present invention bonds a clear plastic foil over the body of a plastic housing having a window for display. The solution creates a chemical and mechanical bond over the entire surface of the housing, not just around the perimeter of the window. This eliminates the potential for seal breakage at the window/housing interface by exposure to water at varying temperatures. The foil overlay may also extend over one or more actuator buttons coupled within other openings in the body of the plastic housing, and similarly provides a moisture seal around these buttons.
Other objects and advantages of the present invention will become apparent upon considering the following detailed description and appended claims, and upon reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a perspective view of a remote function actuator according to one preferred embodiment of the present invention;
FIG. 2 is a section view of FIG. 1 taken along line 1-1; and
FIG. 3 is a logic flow diagram for coupling the clear plastic foil overlay to the upper plastic housing in accordance with the preferred method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The present invention is directed to a method for waterproofing devices having a display window contained therein. The method of the present invention will be described by way of example in forming a remote function actuator having an electronic display. However, it should be understood that the present method is not limited by reference to this example, but is merely exemplary of any number of potential devices that may be formed according to the preferred method.
Referring now to FIGS. 1 and 2, a perspective view of a remote function actuator 20 is shown according to a preferred embodiment of the present invention as having a plastic housing 22 consisting of an upper housing 23 and a lower housing 24, one or more function actuator buttons 26 contained within a first opening 31 of the upper plastic housing 23. The upper plastic housing 23 is sealingly coupled to the lower plastic housing 24 using a water seal 32 such as a molded-in gasket or drop-in gasket (shown herein). The molded-in gasket may be molded as either a portion of the upper plastic housing 23 or as a portion of the lower plastic housing 24. The upper plastic housing 23, lower plastic housing 24, window display 30 and water seal 32 together define an interior region 34.
Coupled within the interior region 34 of the housing 22 is a printed circuit board 36 electrically coupled to an electronic display 38. The printed circuit board 36 is also electrically coupled to the one or more function actuator buttons 26. The electronic display 38 is situated such that it is visible through a second opening 33 in the upper plastic housing 23.
A clear plastic foil overlay 40 is sealingly coupled over the openings 31, 33 in the upper plastic housing 23 and over at least a significant portion of the outer portion 42 of the upper plastic housing 23. A portion of the foil overlay 40 therein constitutes a window display 30 that covers the opening 33. The electronic display 38 is visible through the window display 30. Moreover, the actuator buttons 26 are visible and pressable through the foil overlay 40 during use.
The foil overlay 40 eliminates a water leakage path that typically occurs between the clear lens and inner periphery opening in the upper plastic housing coupled within the opening that commonly occurred in prior art remote function actuators due to the repetitive expansion and contraction of the lens and housing 23 that can occur in the presence of water under varying temperature conditions. The foil overlay also prevents another water leakage pass between the plastic housing and uncovered actuator buttons of the prior art actuator devices.
The plastic housing 22 is preferably formed of a durable polymeric material such as polycarbonate or acrylonitrile-butadiene-styrene (“ABS”) that has been preformed to a desired shape and thickness. The plastic housing 22 may be thermoplastic or thermosetting in nature, and may include various fillers, pigments, light stabilizers, and other additives that are typically utilized to give the plastic housing its desired coloring and durability. As one of ordinary skill recognizes, a thermosetting plastic housing 22 is formed by the reaction of a matrix polymer resin and a crosslinking agent (in the form of another polymer or other reacting material).
The clear plastic foil overlay 40 is preferably formed of a polymeric material that provides good mechanical and chemical adhesion to both the underlying upper plastic housing 23 and window display 30. The foil overlay 40 is a water, chemical, and light-resistant durable polymer material that is substantially clear when cured or otherwise formed to its final shape. The foil overlay 40 may include a number of printed on graphics, button colors, or outside colors as desired. Preferably, the clear plastic foil overlay 40 is formed from about a 0.15-1.25 mm, and more preferably about 0.60 mm thick, sheet of polycarbonate, although the thickness may vary depending upon the application and the desired clarity. Moreover, other polymeric materials that provide good mechanical and chemical adhesion at sufficient clarity and thickness are specifically contemplated by the present invention, including for example thin sheets of polyethylene terephthalate (“PET”) and/or polythiourethane (“PTU”).
Referring now to FIG. 3, a logic flow diagram is shown illustrating the preferred method for forming the plastic foil overlay 40 and coupling the formed overlay 40 to the upper plastic housing 23.
Beginning with Step 100, a thin sheet a suitable clear plastic polymeric material used to make the foil overlay 40 is provided in a flat form at the desired thickness.
Next, in Step 110, the thin sheet is printed with graphics, button colors, and/or outside colors by conventional printing methods well known to those of ordinary skill in the art.
In Step 120, the flat sheet is introduced to a first forming tool and shaped to form a preformed foil overlay, which corresponds roughly to the shape of the foil 40. For a polycarbonate sheet about 0.60 mm thick, the sheet is heated to about 100-110 degrees Celsius and pressed against the inner walls at about 3-5 kilograms of pressure using a vacuum forming or pressing technique to form the preformed foil overlay. The preformed foil overlay is then removed from the first forming tool.
In Step 130, the lower plastic housing 24 is formed to its desired shapes utilizing standard molding techniques. Examples of such techniques include injection molding, compression molding and reaction injection molding. As one of ordinary skill recognizes, the temperature range and pressure range in the particular molding applications vary greatly based on numerous factors, including but not limited to the type of polymer molded, the amount of cavities formed within the mold, and the thickness of the overall part formed.
In the case of a thermoplastic lower plastic housing 24, the liquid polymeric material used to form the lower housing 24 are introduced within the forming tool in a liquid state and allowed to cool and harden to its predetermined final shape. In the case of a thermosetting lower plastic housing 24, the liquid polymeric materials are introduced within the first forming tool and reacted to form the thermosetting lower plastic housing 24.
Next, in Step 140, the upper plastic housing 23 is formed and sealingly coupled to both the foil overlay 40 and around the window display 30 and actuator buttons 26.
To accomplish this, the preformed foil overlay is first coupled within an inner cavity of a second forming tool at a predetermined location. The inner cavity of the second forming tool is shaped to include a plurality of features that correspond to the various contours and shapes of the upper plastic housing 23, including specifically the openings 31, 33 through which the window display 30 and actuator buttons 26 may be displayed.
Next, the polymeric component of the upper plastic housing is injected in liquid form within the inner cavity under heat and vacuum pressure.
The vacuum pressure created within the cavity presses the liquid plastic material against walls on the inner cavity, and specifically presses against the preformed foil overlay 40. Moreover, the liquid polymer is prevented from entering areas corresponding to the openings 31, 33.
The heat generated in the inner cavity of the second forming tool during the injection process also causes the foil overlay 40 to be adhered to the upper plastic housing 23. The upper plastic housing 23 and coupled foil overlay 40, including the formed window display 30, are cooled and removed from the second forming tool.
In the case of a thermosetting upper plastic housing 23, the liquid polymeric materials components of the housing 23, including a polymer matrix resin component and a crosslinking agent, are typically injected separately and mixed and reacted, via a crosslinking reaction, within the cavity. The matrix resin and crosslinking agent therein form a complex polymer network that hardens within the cavity as it reacts to form the thermosetting upper plastic housing. The fully reacted thermosetting upper plastic housing 23 is then cooled and removed from the second forming tool.
In Step 150, the actuator 20 is assembled by sealingly coupling the lower plastic housing 24 to the upper plastic housing 23, which includes the previously coupled foil overlay 40 and formed window display 30, utilizing the water gasket or seal 32, such that the printed circuit board 36, actuator buttons 26, and electronic display 38 are contained within the interior region 34 and coupled to either the lower plastic housing 24 or upper plastic housing 23. The printed circuit board 36 is also electrically coupled to the one or more function actuator buttons 26 and electronic display 38. The actuator 20 is now available for use.
The foil overlay 40 therein prevents water leakage to the interior region 34 of the assembly 20 through openings 31, 33. The solution creates a chemical and mechanical bond over the entire surface of the upper plastic housing 23. This eliminates the potential for seal breakage at the foil/opening interface by exposure to water at varying temperatures.
While the invention has been described in terms of preferred embodiments, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings.

Claims

1. A waterproof remote function actuator comprising:

a plastic housing having a first opening;

a clear plastic polymeric foil overlay coupled over said plastic housing and said first opening, wherein a portion of said clear plastic polymeric foam overlay located over said first opening defines a window display; and

an electronic display contained within said plastic housing and visible through said window display.

2. The waterproof remote function actuator of claim 1, wherein said plastic housing comprises a lower plastic housing sealingly coupled to an upper plastic housing.

3. The waterproof remote function actuator of claim 1 further comprising at least one actuator button coupled within a second opening of said plastic housing and contained within said clear plastic polymeric foil overlay.

4. The waterproof remote function actuator of claim 1, wherein said clear plastic polymeric foil overlay is selected from the group consisting of a clear polycarbonate foil overlay, a clear polyethylene terephthalate foil overlay and a clear polythiourethane foil overlay.

5. The waterproof remote function actuator of claim 1, wherein said plastic housing comprises a polycarbonate plastic housing.

6. The waterproof remote function actuator of claim 1, wherein said plastic housing comprises an acrylonitrile-butadiene-styrene plastic housing.

7. The waterproof remote function actuator of claim 2, further comprising a drop in gasket coupled between said upper plastic housing and said lower plastic housing for sealingly coupling said lower plastic housing to said upper plastic housing.

8. The waterproof remote function actuator of claim 2, wherein said lower plastic housing includes a molded-in gasket for sealingly coupling said upper plastic housing to said lower plastic housing.

9. The waterproof remote function actuator of claim 2, wherein said upper plastic housing includes a molded-in gasket for sealingly coupling said upper plastic housing to said lower plastic housing.

10. A method for forming a waterproof remote function actuator, the method comprising:

providing a thin sheet of a clear polymeric material;

forming a lower plastic housing;

introducing said thin sheet of said clear polymeric material to a first forming tool;

forming a preformed foil overlay from said thin sheet of said clear plastic polymeric material within said first forming tool;

introducing said preformed foil overlay to a second forming tool, said second forming tool having an inner cavity shaped to correspond with a plurality of features contained within said upper plastic housing;

forming an upper plastic housing having a first opening within said inner cavity, said upper plastic housing being sealingly coupled to said preformed foil overlay, wherein a portion of said preformed foil overlay corresponding to said first opening defines a window display; and

sealingly coupling the lower plastic housing to said upper plastic housing, said lower plastic housing and said upper plastic housing defining an interior region there between, wherein said interior region is visible through said window display and said first opening.

11. The method of claim 10, wherein forming a preformed foil overlay comprises vacuum forming a preformed foil overlay.

12. The method of claim 10, wherein forming an upper plastic housing comprises:

providing a polymeric material in a liquid form;

injecting said liquid polymeric material within said inner cavity at a predefined temperature and a predefined vacuum pressure, said liquid polymeric material pressing against said inner cavity and against said preformed foil overlay;

cooling said liquid polymeric material within said inner cavity to form a hardened upper plastic housing; and

removing said hardened upper plastic housing from said second forming tool.

13. The method of claim 12, wherein providing a polymeric material in a liquid form comprises providing a thermosetting polymeric material in liquid form, said thermosetting polymeric material comprising a matrix resin and a crosslinking agent.

14. The method of claim 12, wherein providing a polymeric material in a liquid form comprises providing a thermoplastic polymeric material in liquid form, said thermoplastic polymeric material selected from the group consisting of a thermoplastic polycarbonate-based polymeric material and a thermoplastic acrylonitrile-butadiene-styrene based polymeric material.

15. The method of claim 10, wherein said thin sheet of a clear polymeric material is selected from the group consisting of a clear polycarbonate material, a clear polyethylene terephthalate material and a clear polythiourethane material.

16. The method of claim 10, forming an upper plastic housing having said first opening within said inner cavity comprises:

forming an upper plastic housing having said first opening and a second opening within said inner cavity,

wherein said upper plastic housing is sealingly coupled to said preformed foil overlay and wherein a portion of said preformed foil overlay covers each of said first opening and said second opening.

17. The method of claim 16 further comprising:

coupling an actuator button within said interior region such that said actuator button is contained within said second opening and between said interior region and said preformed foil overlay when said lower plastic housing is sealingly coupled to said upper plastic housing.

18. The method of claim 17 further comprising:

coupling an electronic display and a printed circuit board within said interior region such that said electronic display is visible through said window display when said lower plastic housing is sealingly coupled to said upper plastic housing, wherein said electronic display is electrically coupled to said printed circuit board.

19. The method of claim 18 further comprising electrically coupling said actuator button to said printed circuit board.