Patent Application
20060086020
The present invention relates to the field of flat-panel illuminating sources and more particularly to informational signage.
Informational signage is so common in the built environment that we often hardly notice it. A very common example is the humble exit sign that hangs above doorways and loiters in halls. There are many situations where it is desirable to provide multiple messages, preferably in a small space, often for design considerations, but also for safety reasons as well. In parts of the United States, the exit sign should also say “SALIDA”, whereas in Canada, “SORTIE” is dictated by law. The common backlit and edge-lit designs utilized in the vast majority of these signs makes it impossible to provide two different messages in the same space. Instead, we often see either two signs, or a single sign with two lines of text. While it is possible to implement this functionality using programmable displays, this alternative is expensive, may fail to meet the reliability requirements for critical safety signs, and has relatively high power consumption, which leads to added costs for systems that are required to operate continuously in the face of power outages.
There is therefore a need for signage that is capable of presenting multiple pre-determined messages in the same space at different times.
In accordance with one aspect of the present invention there is provided a multi-mode flat-panel light-emitting sign comprising:
a) a substrate;
b) a plurality of thin-film light-emitting structures located on the substrate, each structure comprised of an anode, a light-emitting layer, and a cathode wherein light-emitting layer has a pattern for providing a visual indicia when the light-emitting structure is activated, the anode and the cathode of each thin-film emitting structure being continuous over the substrate; and
c) a cover provided over the plurality of thin-film light-emitting structures.
In accordance with another aspect of the present invention there is provided a multi-mode flat-panel light-emitting sign comprising:
a) a substrate;
b) two thin-film light-emitting structures located on the substrate, each structure comprised of an anode, a light-emitting layer, and a cathode wherein either the anode and/or cathode has a continuous pattern for providing a visual indicia when the light-emitting structure is activated, the continuous pattern for each of the two thin-film light-emitting structures being electrically in common with each other, the thin-film light-emitting structures being continuous over the substrate; and
c) a cover provided over the two thin-film light-emitting structures.
The Multi-mode Flat-Panel Light-Emitting Sign allows multiple messages to be displayed in the same space, enabling attractive multi-lingual signs, for example. Alternatively, predetermined messages which need to change corresponding to external events or commands are accommodated in the space of a single sign.
These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims and by reference to the accompanying drawings.
In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings in which:
Signs with multiple messages are common in everyday life. Examples include the ubiquitous Open/Closed signs in store windows, elevator direction and floor indicators, bi-lingual exit signs, and so on. There are numerous approaches to self-illuminating multiple message signs, each with one or more shortcomings. Probably the most common form of multiple message self-illuminating sign is comprised of a backlit patterned window, where each message has an individually controllable lamp. By selecting the lamp to light, the sign message is determined. Slightly less common would be an edge-lit variant in which the message is etched into a transmissive medium such as glass and each message is individually edge-lit by a lamp. While these approaches can be quite economical, each message requires a distinct area and is generally readable even when not illuminated. A second approach is to produce a series of neon lamps, one for each message. The lamps are stacked one in front of the next. The lamp corresponding to the desired message is provided with electrical current that causes it to glow. This approach eliminates the need to provide a distinct area for each message. This is achieved, however, at the cost of degraded readability. In addition, the sign becomes fairly thick and forming the glass for neon is a challenging and expensive process. Yet a third alternative is to display the message on a general-purpose, programmable pixellated display device. While this approach provides tremendous versatility in message selection, the versatility comes with added complexity and cost. In addition, unless the display pixels have a fine pitch, it is often not possible to select the font or other appearance characteristics of the message. Examples of this class of display include active- and passive-matrix emissive displays, be they made from LCD, LED, OLED, or other technology.
The first OLED layer 15 is patterned in the form of the first message and the second OLED layer 25 is patterned with the second message. When power is provided to the first anode 10 and the common cathode 20, the first message becomes visible. When power is provided to the second anode 30 and the common cathode 20, the second message becomes visible. When power is applied to both anodes using the common cathode as a ground, both messages are simultaneously visible.
Depending upon details of the manufacturing process, it may be desirable to pattern the first and second anode layers 10, 30 rather than the first and second OLED layers 15, 25. Alternatively, we can replace the common, unpatterned cathode 20 with a distinct patterned cathode for each message, which then allows us to utilize unpatterned anode and OLED layers. Another alternative is to interpose a patterned insulating layer between the anode and OLED layers or cathode and OLED layers. This allows us to produce unpatterned anode, cathode, and OLED layers, at the expense of a patterned insulating layer.
Regardless of whether the patterning for the message is in the anode, cathode, or OLED layer, it is possible to form the OLED layer from multiple emitter types such that distinct regions of the OLED layer emit in different colors, permitting a single message to contain multiple colors.
The cover 35 and substrate 5 may be made of transparent glass or may have reflective layers deposited on them. OLED layers are typically very thin and are also relatively transparent. Electrodes may be made of transparent materials, for example indium tin oxide or thin, transparent layers of metals such as silver and aluminum. Alternatively, electrodes may be reflective, for example made of thick metal layers. All these materials and techniques for their deposition are known in the art. In this way, light emission from either or both sides of the light-emitting sign 8 may be controlled.
The multiple message light-emitting sign 8 shown and described above emits light from both sides 42, 44 with the same message visible from either side, although one side will read as a mirror image. When the sign 8 is unpowered, it is transparent, becoming unobtrusive. We can replace the transparent common cathode with a reflective common cathode (or multiple cathodes). In this case, each side of the sign contains an independently controlled message. Yet another alternative is to make one of the anodes reflective, keeping a transparent cathode and one transparent anode. This configuration provides a sign in which all modes are visible from one side and invisible from the other.
As shown in
It is to be understood that various changes and modifications may be made without departing from the scope of the present invention, the present invention being limited by the claims that follow.
42 Side
