Display device with molded light guide
A display device includes a base with at least one light device. A conductive layer is provided on the base and is electrically coupled to the light device. A light guide is formed the base and the conductive layer, and includes an aperture surrounding the light device and having a profile for directing light from the light source outwardly from the base.
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The present application claims the benefit of priority as available under 35 U.S.C. 119 (e)(1) of U.S. Provisional Patent Application No. 60/406,434 titled “Display Device” filed on Aug. 28, 2002 and U.S. patent application Ser. No. 10/608,667 titled “Display Device” filed on Jun. 27, 2003 (the entire disclosures of which are incorporated by reference).
FIELDThe present invention relates to a display device. The present invention relates more particularly to a molded light guide for use in display devices with printed circuit boards and light sources.
BACKGROUNDThe use of optoelectronic devices with light guides for dispersing or focusing the light from bulbs or other light emitting devices is generally known. Such guides may be provided on printed circuit boards having groupings or arrays of LEDs or other light emitting devices for providing displays such a sign or message board assembly. However, the known light guides are often susceptible to problems associated with the physical attachment of the light guide to the printed circuit board. For example, the electrical interconnections between the light source and the circuit board are typically delicate and may be easily damaged through the handling and installation of the light guide onto the circuit board. Also, gaps are often present between the light guide and the circuit board, resulting in leakage of the emitted light along the sides of the circuit board. Also, the application of a molded light guide to a printed circuit board has typically resulted in warping or physical distortion of the assembly. Further, providing an array of LEDs on a printed circuit board and attaching a light guide for use in displays often results in individual LEDs within the array having various degrees of uniformity in color and brightness, thus leading to display images having less uniformity in the optical performance of the device than desired.
Accordingly, it would be advantageous to provide a display device having one or more of the following features alone or in combination with one or more of the other features: a light guide that is molded to a printed circuit board for developing a desired light emission profile, a light guide that is adhered directly to a printed circuit board to minimize light leakage and avoid the use of external attachment devices such as adhesive tape, a light guide that does not require a degassing operation, a light guide that does not result in warping or physical distortion of the assembly, a light guide that provides protection for electrical interconnections and components to create a more robust assembly, a light guide that upon assembly can be separated into individual pixels for matching and grading uniformity and performance of the individual pixels for assembly into a display unit, or a light guide that may be used as an optical coupling device.
SUMMARYOne aspect of the present invention relates to a display device and includes a base with at least one light device, a conductive layer provided on the base and electrically coupled to the light device, and a light guide formed on the base and the conductive layer, and having at least one aperture surrounding the light device.
Another aspect of the present invention relates to a display device having a base with at least one light source, and a layer of material disposed on the base and having at least one aperture defining a profile with the light source for directing light from the light source outwardly from the base.
BRIEF DESCRIPTION OF THE DRAWINGS
In the various drawings, like reference numerals are used to indicate like components.
DETAILED DESCRIPTION Referring to
Display device 10 includes a base member (shown schematically as a substrate material 20), a conductive material provided thereon forming a circuit pattern, light devices 22 such as a light receiving device or a light transmission source (such as a visible light source, shown schematically as LEDs in
Referring further to
In a preferred embodiment, the light sources are LEDs that are provided in a sixteen (16) by sixteen (16) array and the substrate is approximately seventy-one millimeters in length and approximately seventy-one millimeters in width, with a thickness of approximately 0.5 millimeters. The LEDs are attached to the conductive material 25 of substrate 20 by a die attachment method, such as with silver epoxy conductors, or by other suitable methods. The LEDs may be discrete color LEDs configured to emit light in a single color (e.g. monochromatic), such as white, red, green or blue, or multicolor LEDs (e.g. red, green and a mixture of red and green to create amber) or may be any suitable combination of LEDs of individual colors to provide the desired display image on display device 10. In a preferred embodiment, substrate 20 is made of a ceramic material for providing electrical insulation for circuitry 26 and to provide suitable heat transfer for heat generated by the light sources, but may be made of any suitable material such as phenolic, fiberglass, paper or other conventional types of materials commonly used in circuit board applications. The substrate 20 includes interfaces (shown schematically as openings or cylindrical apertures 24 in
Referring further to
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The space within the aperture 40 may be unfilled (e.g. air space), or may be filled with an encapsulating or fill material (e.g. potting, etc.) for sealing and enhancing the optical image (e.g. intensity, color, color mixing, etc.) of light source 22. In a preferred embodiment, a fill material 45 shown schematically as a clear epoxy is provided that enhances the durability of the display assembly 10 and provides the desired optical emission of light from the light source. The fill material may be allowed to cure under ambient conditions or may be oven-cured to expedite manufacturing processing time. The fill material may result in a surface that is concave (as shown schematically in
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In a preferred embodiment, the individual pixels 50 are individually tested and graded according to established operating criteria and performance standards (e.g. conductivity, brightness, color, clarity, etc.) and “binned” or segregated into groups having like or similar performance characteristics. The segregated groups of pixels may then be used to assemble signs, displays or message boards comprised of individual pixels having relatively uniform and consistent display characteristics, or for positioning lower grade pixels in certain areas of the sign, display or message board that are more optically or aesthetically acceptable. The segregated groups of pixels may also be assembled into graded pixels blocks (having any suitable number of pixels of like or otherwise desirable performance characteristics) that may then be assembled as components of larger signs, displays or message boards having the desired pixel performance and display qualities. Such separated display device portions, individual pixels or pixel blocks may be used for rapidly assembling custom-order signs, displays or message boards without having to specially create a new display device for each new application.
Display device 10 may be formed as an individual unit for use in various LED display devices, alphanumeric message boards, signs, etc. including (by way of example) taxiway signs or signs for transportation depots or facilities (e.g. airports, railway stations, bus stations, ports, highways, etc.), having suitable software for displaying multilingual messages, retrofit LED display boards for drop-in display modules that replace or supplement conventional display signs or provide enhanced messaging or imaging capability with existing displays in commercial (restaurants, stores, shopping centers, etc.), industrial (factories, offices, manufacturing and assembly facilities, etc.), institutional (schools, libraries, hospitals, etc.) or governmental facility signage or display applications. Such display devices may also be used in one or more arrays for residential applications, such as to provide lighting (e.g. normal or emergency), in which the circuitry is suitably coupled to a circuit device (not shown) for converting standard residential electrical power, such as 120 volts AC and 60 hertz, or from a back-up source, to a suitable power level adapted for use by the display device.
The structure of the display device may be used in other applications for transmitting and receiving light. For example, the light guide may be used as an integral component with any optoelectronic device. The light guide, substrate, and suitable circuitry may be configured as mating halves of a coupler (e.g. plug, connector, interface, etc.) for coupling, modulating or amplifying light signals between various devices. For example, a “plug” having suitable light transmission or receiving structure, or electrical conductivity device, may be molded onto the top or bottom of the display device and configured to interconnect with other pugs or devices. The light guide may also be used with suitable substrates and circuitry for night vision applications and for coupling of fiber optic devices. In fiber optic applications, the light guide may be used as an optical coupler for use in “plugs” or connectors configured to fit together for transmitting and receiving light signals among various equipment.
Display device 10 may also be used for upgrading existing displays or signage or for providing additional display capabilities by sizing the display assembly 10 for use as a “drop-in” replacement for an existing sign, panel or display, particularly in applications that would otherwise require application for a new “permit” or other authorization where necessary for use of a new or replacement sign or display. Additionally, multiple display assemblies may be grouped together and coordinated with suitable messaging or imaging software to provide alphanumeric or imaging displays (e.g. single color or multicolor) for large scale signs, such as (by way of example) large display applications including stadium scoreboards, electronic billboards, video devices, viewing screens and the like.
Referring to
Signal 60 according to the embodiment may be provided as a substantially flat panel display device adapted for installation on a surface, such as a vehicle panel 64, without the necessity for wells, recesses or compartments in the body of vehicle 62 as are typically required for conventional vehicle signal devices. Such surface installation may provide increased space within the interior of vehicle 62 and reduce the complexity and time associated with vehicle panel forming operations and assembly activities. Of course, signal 60 could be positioned in a similar manner as are conventional light bulbs by placing them in a housing under a lens or transparent cover.
According to any preferred embodiment, the display device includes a substrate material (such as ceramic, etc.), having a conductive material (such as gold, etc.) provided thereon in a suitable pattern to provide a circuit board configured to interface with one or more light sources and a control circuit (e.g. external). A moldable material is molded onto one or both of the substrate and conductive material to provide a light guide that surrounds a portion of the circuitry that is adapted for mounting one or more light sources thereon. The substrate may have suitable structure (such as apertures) intended to improve the adhesion of the light guide to the substrate. One or more light sources (such as LEDs) are installed on the substrate and electrically interconnected to the appropriate portions of the circuitry (e.g. by conductive epoxy, wires, etc.). If desired, the light sources may be encapsulated within the light guide by a suitable material (e.g. epoxy, etc.).
According to any preferred embodiment, the display device may be manufactured by providing a substrate material, providing a conductive overlay material to form the desired circuit patterns thereon, molding a light guide onto the substrate and conductive material, installing the light source(s) on the appropriate portion(s) of the circuit patterns, installing the electrical interconnections between the light source(s) and the appropriate portion of the circuit pattern, encapsulating the light source(s) within the light guide. If desired, the display device can be separated (e.g. cut, sawed, diced, etc.) into individual pixels that may be graded and “binned” for use in assembling graded pixel blocks. The formation of the light guide on the substrate and/or the conductive material prior to installing and electrically interconnecting the light source(s) is intended to improve the durability and ruggedness of the device. Further, the installation of the encapsulating material after electrical interconnection of the light sources is also intended to improve the durability and ruggedness of the device.
It is important to note that the construction and arrangement of the elements of the display device provided herein are illustrative only. Although only a few exemplary embodiments of the present invention 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 in these embodiments (such as variations in installation location and orientation, sizes, structures, shapes, angles and proportions of the various elements, mounting arrangements, use of materials, combinations of shapes, etc.) without materially departing from the novel teachings and advantages of the invention. For example, the light guide may be used in any application for directing, focusing or dispersing the light emitted from a display, sign, message board or other light transmitting or receiving system. Also the light guide may have any suitable shape, length, thickness, location or orientation for use in connection with manufacturing large arrays of light sources such as, but not limited to, LEDs and separating the large array into groups of smaller arrays. Additionally, the light guide may be used with any suitable light emitting device surface other than printed circuit boards having LEDs. The light guide may be used to control the outward emission of light from the LEDs, or may be used to receive light from a source (e.g. fiber optics source, etc.) configured to interface with a printed circuit board. Further, it is readily apparent that the light guide may be provided in a wide variety of shapes, sizes, thickness, and light distribution profiles and adapted for installation on any size printed circuit board. Additionally, the sign, message board, imaging screen or information display may be any display adapted to visually convey alphanumeric messages, signals, information or images for use in original design applications or for use in retrofit applications for replacing, enhancing or upgrading existing signs or display devices. Accordingly, all such modifications are intended to be within the scope of the invention.
While the present invention has been described in connection with a particularly preferred embodiment thereof, the invention is not to be limited by the drawings. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating configuration and arrangement of the preferred and other exemplary embodiments without departing from the spirit of the inventions as expressed in the appended claims.
Claims
1. A display device, comprising:
- a base;
- at least one light device coupled to the base;
- a conductive layer provided on at least a portion of the base and electrically coupled to the light device; and
- a light guide formed on the base and the conductive layer, and having at least one aperture surrounding the light device.
2. The display device of claim 1 wherein the base includes at least one opening configured to receive a material used in the formation of the light guide.
3. The display device of claim 2 wherein the opening is a plurality of cylindrical openings disposed adjacent the light source.
4. The display device of claim 2 wherein the conductive layer extends at least partially through the opening.
5. The display device of claim 2 wherein the light guide is molded in a securing relationship with the opening.
6. The display device of claim 1 wherein at least one conductive pad is provided on an underside of the base and configured to provide electrical connectivity with the light device.
7. The display device of claim 1 wherein the conductive layer provides a circuit.
8. The display device of claim 7 wherein the circuit includes a cathode and at least one anode for connecting the light device.
9. The display device of claim 8 wherein the light device is substantially centered within the aperture.
10. The display device of claim 1 wherein the aperture is defined by side walls having a truncated cone shape.
11. The display device of claim 1 wherein the light device is a single color LED.
12. The display device of claim 1 wherein the light device is a multicolor LED.
13. The display device of claim 1 further comprising a contrasting coating provided on the light guide.
14. The display device of claim 1 further comprising an optical coating.
15. The display device of claim 1 wherein the light device is encapsulated within the aperture by a fill material.
16. The display device of claim 1 wherein the display assembly is a one of a sign, a display panel and a message board.
17. The display device of claim 1, wherein the display assembly is adapted to provide a message in a first language and a second language.
18. The display device of claim 1, wherein the display assembly is a retrofit display assembly adapted to replace an existing display.
19. The display device of claim 1, wherein the display assembly is a taxiway sign.
20. A display device, comprising a base with at least one light source atop the base, and a layer of material disposed on the base, the layer of material having at least one aperture surrounding the light source and defining a profile for directing light from the light source outwardly from the base.
21. The display device of claim 20 wherein the base includes at least one opening configured to receive a portion of the layer of material.
22. The display device of claim 20 wherein the profile comprises a truncated cone shape.
23. The display device of claim 20 wherein the profile comprises a parabolic shape.
24. The display device of claim 20 further comprising a conductive material disposed on the base to provide a circuit configured for electrical connection with the light source.
25. The display device of claim 24 wherein the base and the conductive material are configured to form a circuit board.
26. The display device of claim 20 wherein the light source is an LED.
27. The display device of claim 26 wherein the LED is a multicolor LED.
28. The display device of claim 26 wherein the LED is a monochromatic LED.
29. The display device of claim 20 further comprising a fill material disposed within the aperture.
30. The display device of claim 20 wherein the light source comprises a plurality of light sources, and the base and the layer of material and the light sources are configured for separation into a plurality of pixels.
31. The display device of claim 30 wherein the plurality of pixels are configured for separation by a dicing saw.
32. The display device of claim 30 wherein the pixels are evaluated to establish a grade according to a set of performance characteristics.
33. The display device of claim 32 wherein the pixels are grouped into one or more groups according to the grade.
34. The display device of claim 33 wherein the pixels from one of the one or more groups are assembled into one or more display blocks of the pixels.
35. The display device of claim 34 wherein the one or more display blocks of the pixels are assembled into a display assembly.
36. The display device of claim 35 wherein the display assembly is one of a sign, a message board and an information display.
37. The display device of claim 35 wherein the display assembly is a retrofit display assembly.
Type: Application
Filed: Jun 16, 2006
Publication Date: Oct 26, 2006
Applicant:
Inventors: Thomas Mandler (Grafton, WI), Jason Lai (Taipei), William Latz (Brookfield, WI)
Application Number: 11/454,487
International Classification: F21V 7/00 (20060101);