Patent Grant
8628229
1. Field of the Invention
The present invention relates generally to frames for transparent or translucent displays, and more particularly, to side-lit displays.
2. Description of the Prior Art
Displays of art and information have always been a part of man's life. Most such displays have been front lit, where light shines on the object of interest, and front lighting continues to dominate, from the heights of art to the mundane such as posted schedules at bus stops.
With the advent of artificial lighting and the ability to produce and reproduce pictures and information on transparent or translucent materials, backlit displays have evolved, where light shines through the object being displayed.
One form of backlit display uses a light box containing a light source such as a plurality of fluorescent lamps, with a transparent or translucent display object on the front of the light box. Unless the light box has sufficient depth to provide for diffusion of the light from the lamps, a diffusion layer is placed between the lamps and the display object to diffuse the light, providing even levels of light over the display object. Such light boxes tend to be large and bulky to house the fluorescent lamps. The lamps and their ballasts generate heat. Fluorescent tubes have a finite operating life and must be replaced when they fail. With these limitations, light boxes are widely used to display pictures and information.
A premier example of a light box display was the Kodak Colorama at the East balcony of New York City's Grand Central Terminal, which displayed 18×60 foot rear-lighted transparencies for forty years, from 1950-1990.
More mundane examples of fight box displays include back-lit advertising displays in airports and other public and commercial venues, menu and product displays at fast food establishments, and the like.
Back-lit and light box display technology changed with the development of inexpensive light emitting diodes (LEDs), particularly with the availability of powerful LEDs capable of producing white light.
With LEDs, the bulky light box filled with fluorescent tubes is transformed into a thinner package featuring a side lit light guide.
The light guide is typically an acrylic plastic panel 4 mm or more in thickness with a white reflective backing and a treatment for dispersing light from the front surface of the panel. This treatment may be in the form of etched or printed patterns on the front surface of the panel, or in small particles dispersed within the panel.
The light guide panel is side lit using LEDs. LEDs are mounted to direct their light into the edges of the light guide panel. Depending on the size of the light guide panel, the intensity of the LEDs, and the amount of light required, LEDs may be placed along one or more sides of the light guide panel.
The resulting side lit framed panel is much thinner than older light boxes, and relatively maintenance free through the use of long life LEDs.
A problem arises with these panels. For commercial applications involving large quantities, they are economical when compared with older technologies.
But for other than standard sizes and large quantities, the economies are not present. Frames for side lighting are made in standard sizes in large quantities. But such frames are not amenable to the myriad of shapes and sizes required for framing art in the real world; art seldom deals in standard sizes, nor can such art be easily resized to fit a standard. Nor is it economical to build one or two custom-sized side lit frames at a time.
What is needed is a way to adapt such side lit frames to a wider range of sizes.
In one embodiment is provided a modular illuminated frame member for framing a transparent or translucent flat display article such as a photograph or informational display. The display article is mounted to a light guide assembly. One or more modular illuminated frame members frame the light guide assembly and supply side illumination to the light guide; this illumination is directed out of the light guide assembly through the display article. These frame members may be enclosed in a decorative outer frame. The modular illuminated frame member comprises two or more light emitting diode (LED) lighting modules mounted in a channel in the frame member, directing light from the LEDs into an edge of the light guide. The number of LED lighting modules in the modular illuminated frame member determines the length of the modular illuminated frame member. Illuminated frame members of different lengths are produced using different numbers of LED lighting modules. The frame member may be a metal such as aluminum, or other material, and may be cast, extruded, machined, or produced by other known forming processes. The LED lighting modules are mounted in a channel in the frame member sized to fit the light guide assembly. The spacing between a top surface of the LEDs and the edge of the light guide assembly may be determined by either direct contact between the top surface of the LEDs and the edge of the light guide assembly, or by a spacer element establishing a separation between the top surface of the LEDs and the edge of the light guide assembly. The frame member may provide heat sinking to the LEDs; additional heat sinking may be provided by a heat conductive backing on the light guide assembly such as an aluminum plate. Dummy frame members, without LED lighting modules, are provided in modular lengths.
Using the modular illuminated frame members and the corresponding modular dummy frame members, a wide range of display articles may be framed using a set of standard components.
In one embodiment, a modular illuminated frame member comprises a channel element having a front member, a rear member, and a side member joining the front and rear members, where a distance between the front and rear members of the channel element is sized to be approximately equal to the thickness of a light guide assembly, and a modular light emitting diode (LED) lighting strip having two or more LED lighting modules, each LED lighting module having a substrate and a light emitting diode (LED) attached to the substrate, the LED lighting strip attached to the side member between the front and rear members wherein the LED lighting strip is adapted to set a distance between the LEDs on the two or more LED lighting modules and an edge of the light guide assembly, and wherein a length of the modular illuminated frame member is determined by the number of the two or more LED lighting modules present in the LED lighting strip.
In one embodiment a modular framing system comprises a modular illuminated frame member having an illuminated channel element with a front member, a rear member, and a side member joining the front and rear members, where a distance between the front and rear members of the illuminated channel element is sized to be approximately equal to a thickness of a light guide assembly, and a modular light emitting diode (LED) lighting strip having two or more LED lighting modules, each LED lighting module having a substrate with an LED and a spacer element both attached to the substrate, the LED lighting strip attached to the side member between the front and rear members wherein the LED lighting strip is adapted to set a distance between the spacer element on the two or more LED lighting modules and an edge of the light guide assembly, and wherein a length of the modular illuminated frame member is determined by the number of the two or more LED lighting modules present in the LED lighting strip; and a dummy modular frame member having a dummy channel element, the dummy channel element having a front member, a rear member, and a side member joining the front and rear members, wherein a distance between the front and rear members of the dummy channel element is sized to be approximately equal to the thickness of the light guide assembly, and wherein an inset depth of the dummy modular frame member is the same as an inset depth of the modular illuminated frame member.
a is a diagram of modular frame members according to another embodiment.
b is a diagram of modular frame members according to another embodiment.
Described herein are various embodiments of modular illuminated frame members used to frame and illuminate a transparent or translucent display article such as a photograph or informational display. A display article is mounted to a light guide assembly. One or more modular illuminated frame members frame the light guide assembly and supply illumination to the light guide; this illumination is directed out of the light guide assembly through the display article. The framed display article may be enclosed in a further decorative frame.
The modular illuminated frame member comprises a channel containing two or more light emitting diode (LED) lighting modules. One or more LEDs in each LED lighting module direct light into an edge of the light guide assembly. In some embodiments, spacing between a top surface of the LEDs and the edge of the light guide is maintained by either having the top LED surface in direct contact with the edge of the light guide assembly, or by a spacer element maintaining the separation between the top LED surface and the edge of the light guide assembly. The frame member may be made of metal, such as aluminum, or other materials, and may be produced by casting, extrusion, milling, or other known forming processes. The frame member may be used as a heat sink for the LEDs. A backing of the light guide assembly may also be used as a heat sink. The number of LED lighting modules determines the length of the channel and of the frame member. Illuminated frame members of different lengths are produced using different numbers of LED lighting modules. Dummy frame members of these same lengths are also produced without the LED lighting modules.
In use, display articles of a wide range of sizes may be framed using a set of different sized modular illuminated frame members and modular dummy frame members.
Referring now to
Channel 200 has a front member 200a, a rear member 200c, and a side member 200b joining front member 200a and rear member 200c. LED lighting modules 220 are attached to side member 200b. For example, as mounted on a wall, rear member 200c faces the wall, and front member 200a faces away from the wall.
In one embodiment, channel 200 is made of a metal such as aluminum, although other materials may be used. The channel may be machined, extruded, cast, or produced using other techniques known to the forming arts. While other materials may be used, such as plastics or filled plastics, materials which may serve as heat sinks for dissipating the heat produced by LED lighting modules 220 are preferred.
Each LED lighting module 220 comprises a substrate 230 to which is mounted one or more LEDs 240, and optionally a spacer element 250. Not shown are power distribution traces on substrate 230, and support components for LED 240. Support components for LED 240 could be as simple as a current-limiting resistor as is known to the art, or as complex as a constant-current source or an addressable LED controller. In one embodiment, six LEDs are used per module.
Power connections 260 electrically connect a set of LED lighting modules 220 forming a LED lighting strip 210 to additional LED lighting strips in other modular illuminated frame members, or to an external power source. While two lines 260 are shown representing a simple power connection, more lines may be used if, for example, LED lighting modules 220 contain controller circuitry requiring more lines for data.
In one embodiment, LEDs producing white light are used; other embodiments may use LEDs of other colors, including red-green-blue (RGB) LEDs with integrated controllers. Optionally, LEDs may be matched or selected for color balance and intensity. Color balance and intensity may be less critical with certain display articles, such as product displays, but may be more critical in others, such as photographs or artworks.
Substrate 230 may be a common epoxy-fiberglass substrate used for printed circuit boards known commercially as FR4. Other substrates such as phenolics may be used. A substrate such as Kapton® may also be used. Thermal vias, known to the printed circuit arts, may be placed in substrate 230 underneath LEDs 240 to aid heat transfer away from the LEDs.
The number of LED lighting modules 220 present determines the length of channel 200, and of modular illuminated frame member 100. A shorter channel can contain fewer LED lighting modules, and a longer channel can contain more, with the lengths available for modular illuminated frame member 100 related to multiples of the length of an individual LED lighting module 220.
In practice, light guide assembly 110 is typically a plastic material such as an acrylic plastic sheet 4 mm or more in thickness with a reflective backing applied to the rear surface of the acrylic sheet, the display article applied to the front surface, and light introduced to one or more edges. Light from LED lighting modules 220 enters edge 312 of the light guide assembly. This light is dispersed to the front surface of the light guide assembly, illuminating the transparent or translucent article on the light guide assembly. In one embodiment, a 4 mm acrylic panel, a white reflective backing layer, and a 2 mm aluminum backing plate are combined to form a light guide assembly. Use of a backing material such as aluminum also allows the use of the backing material as a heatsink, as will be described.
Channel 200 has a front member 200a, a rear member 200c, and a side member 200b joining front member 200a and rear member 200c. LED lighting modules 220 are attached to side member 200b. In one embodiment this attachment is made using an adhesive 310 between substrate 230 and channel side member 200b.
Adhesive 310 may be chosen for its thermal properties, supporting the use of channel 200 as a heat sink for LEDs 240. For example, a double-sided heat-transfer tape such as 3M® Thermally Conductive Adhesive Transfer Tapes may be used as an adhesive. Thermal transfer epoxies may also be used; these are available from 3M® and other manufacturers.
Non-adhesive solutions may also be used, such as screws, rivets, or other means to secure substrate 230 to the channel side member 200b. Multiple approaches may also be used, as an example, combining screws with a heat transfer material.
Heat transfer materials between substrate 230 and channel side member 200b aid in removing heat from LEDs 240, reducing their temperature. Non-adhesive heat transfer solutions are available, and may be used in some embodiments, including hut not limited to thermal grease or paste, non-adhesive tapes, and the like.
In some embodiments, to provide uniform illumination through light guide assembly 110, the distance between edge 312 of light guide assembly 110 and LEDs 240 is controlled; variations in spacing can result in variations in illumination.
One embodiment maintains a uniform spacing between a top surface of LEDs 240 and edge 312 of light guide assembly 110 by having edge 312 in direct contact with the top surface of LEDs 240.
In another embodiment, uniform spacing between edge 312 of light guide assembly 110 and the top surface of LEDs 240 is maintained by spacer elements 250 mounted to substrate 230. The use of spacer elements 250 may be desirous when a small, uniform gap between the top surface of LEDs 240 and edge 312 of light guide assembly 110 is desired. Such a gap may be desirable, for example, if the operating temperature of LEDs 240 would deform the material used for light guide assembly 110. In such embodiments it is desirous to maintain a small yet uniform gap; variations in the spacing between the top surface of LEDs 240 and edge 312 of light guide assembly 110 result in variations in illumination, which are to be avoided. Spacer elements 250 therefore provide a uniform spacing.
When used, spacer elements 250 need not be present on every LED lighting module 220 in a LED lighting strip 210, or between each pair of LEDs 240 in a single LED lighting module. As an example, spacer elements 250 may be placed on every other LED lighting module 250 in a LED lighting strip, every third LED lighting module, one spacer element 250 at each end of the LED lighting strip and one spacer element 250 in the middle of the LED lighting strip, and so on.
As shown in the figure, an inset depth 330 is defined as the distance between the edge of front member 200a and spacer element 250 if a spacer element is present. If spacer element 250 is not used in an embodiment, the inset depth 330 is defined as the distance between the edge of front member 200a and the top of LED 240. In either case, this inset depth 330 is the distance that light guide assembly 110 can be inset into channel 200 of modular illuminated frame member 100.
Modular illuminated frame member 100 may be finished, for example by anodizing or painting, for display as the frame for the display article. In other embodiments, modular illuminated frame member 100 is clad in, or attached to, a surrounding frame 320 as shown in the Figure. This allows for a more traditional frame 320 to be presented visually, hiding modular illuminated frame member 100 from view. As shown, a traditional frame 320, such as a wood frame, may be prepared to receive a frame comprising modular illuminated frame members 100.
An additional embodiment of modular illuminated frame member 100 is shown in end view in
As also shown in this embodiment, rear member 200c is adapted to allow light guide assembly 110 to be inserted into channel 200 at an angle, allowing for ease of assembly. By placing an adhesive 420 on rear member 200c as shown, modular illuminated frame member 100 may be attached to light guide assembly 110 for example by sliding modular illuminated frame member 100 on to light guide assembly 110 at an angle until edge 312 meets either spacer elements 250 or LEDs 240, then rotating modular illuminated frame member 100 and pressing channel edge member 200c with adhesive 420 on to light guide assembly 110. When adhesive 420 has set, an attachment has formed, allowing frame assembly in this embodiment without the use of fasteners. A double-sided adhesive tape may be used for adhesive 420, providing for rapid assembly. As an example, a high strength bonding tape such as VHB® tape from 3M® may be used.
In some embodiments, light guide assembly 110 has a metal back plate. In such embodiments, the use of a heat transfer material for adhesive 420, such as thermal transfer tape or a thermal transfer epoxy facilitates the use of the metal back plate of light guide assembly 110 as an additional heatsink, dissipating the heat generated by LEDs 240 through channel 200 and light guide assembly 110.
a and 5b show modular frame members according to additional embodiments. Particularly when the frame members are encased in an outer decorative frame such as that shown as 320 of
Also shown is a wire routing 630 accommodating wiring from or between other modular illuminated frame members forming a complete frame. Providing wire routing in both illuminated frame members and dummy frame members allows wiring between illuminated frame members to be enclosed within the frame members.
Referring again to
Light reflective material 410 is applied to the rear surface of front member 200a, which reflects light back into light guide assembly 110. In some embodiments, this light reflective material is also applied to at least a portion of side member 200b adjacent to edge 312 of light guide assembly 110.
The overall framing process is simplified by using modular connectors. By providing connectors in illuminated frame members and dummy frame members, a frame may be assembled quickly and easily.
In use, an artist or a framing shop would stock modular illuminated framing members and dummy framing members in various lengths, as well as light guide material. Given a translucent or transparent display article to be framed, modular frame members, both modular illuminated frame members, and dummy members are selected to frame the article. As is understood in the framing arts, a mat, which is an opaque material cut to reveal the object and extending to the frame members, may be used. Once dimensions are established, the light guide assembly is cut and assembled. A trial fit may be performed using illuminated and dummy frame members to form the illuminated frame. Dummy frame members may be swapped out for modular illuminated frame members if more illumination is desired for the display article. The illuminated frame is assembled by attaching the frame members to the light guide assembly. If the illuminated frame is to be inset in an outer decorative frame such as shown in
Given the various sizes of the modular illuminated frame members, and the corresponding modular dummy members, a wide range of articles can be framed using an assortment of these modular parts.
As is understood in the light emitting diode arts, intensity control of LEDs over a wide range is not accomplished by varying the voltage across the LED, but by applying a constant voltage at a varying duty cycle. This is also known as pulse width modulation (PWM). In the embodiments disclosed herein, such pulse width modulation for intensity control may be supplied by an external power source, or may be included in the drive electronics associated with each LED lighting module. In one embodiment, PWM is combined with a wireless remote control allowing remote control of illumination level.
It is to be understood that the examples given are for illustrative purposes only and may be extended to other implementations and embodiments with different conventions and techniques. While a number of embodiments are described, there is no intent to limit the disclosure to the embodiment(s) disclosed herein. On the contrary, the intent is to cover all alternatives, modifications, and equivalents apparent to those familiar with the art.
In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. Various features and aspects of the herein-described invention may be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. It will be recognized that the terms “comprising,” “including,” and “having,” as used herein, are specifically intended to be read as open-ended terms of art.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5815971 | Rothe et al. | Oct 1998 | A |
| 20060285358 | Chen et al. | Dec 2006 | A1 |
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