Abstract:
A device for forming a dynamic image on an aircraft sign includes a plurality of light sources, an input power line, a first timer and a second timer both connected to an enable input and a plurality of delay circuits each connected to a different one of the light sources. The system also includes a counter having a plurality of counter outputs, the counter receiving a counting pulse from the first timer in a dynamic mode of operation and disable signal from the second timer after expiration of a preset time, the expiration of the preset time causing the device to transfer from the dynamic mode to a static mode where each of the plurality of light sources are simultaneously illuminated.

Description:
FOREIGN PRIORITY 
       [0001]    This application claims priority to India Provisional Patent Application No. 201611025878 on Jul. 28, 2016, the entire contents of which is incorporated herein by reference. 
       BACKGROUND 
       [0002]    The present disclosure relates generally to aircraft and more specifically, to actively controller indicator signs. 
         [0003]    Passengers on aircrafts are able to view illuminated signs throughout the cabin. These warning and indicator signs include seat belt signs, attendant signs, and non-smoking signs. As the needs of the airlines change more indicators will become useful. Current sign boards are static. Backlights (e.g., diodes or other light sources) in the sign boards are glowing constantly to show the instructions printed on the lens to the passenger. 
         [0004]    For example,  FIGS. 1A and 1B  show examples of a static EXIT sign. The sign  100  includes letters  102  that, in this example, spell out the word EXIT but other words could be used, and of course, the words could also be in another language. The signs  100  also includes arrows  104   a / 104   b  that “point” to an exit location. Such a sign  100  may be located in an overhead position in aircraft. 
         [0005]    In some cases, the Federal Aviation Regulations (FARs) have certain aircraft sign requirements. For example, FARs PART-25 relates to emergency exit signs and require that airplanes that have a passenger seating configuration, excluding pilot seats, of 10 seats or more must meet the following requirements: (i) Each passenger emergency exit locator sign required by §25.811(d)(1) and each passenger emergency exit marking sign required by §25.811(d)(2) must have red letters at least 1½, inches high on an illuminated white background, and must have an area of at least 21 square inches excluding the letters. The lighted background-to-letter contrast must be at least 10:1. The letter height to stroke-width ratio may not be more than 7:1 nor less than 6:1. These signs must be internally electrically illuminated with a background brightness of at least 25 foot-lamberts and a high-to-low background contrast no greater than 3:1. 
       BRIEF DESCRIPTION 
       [0006]    A device for forming a dynamic image on an aircraft sign is disclosed. The device includes a plurality of light sources, an input power line, a first timer and a second timer both connected to an enable input and a plurality of delay circuits each connected to a different one of the light sources. The device further includes a counter having a plurality of counter outputs, the counter receiving a counting pulse from the first timer in a dynamic mode of operation and disable signal from the second timer after expiration of a preset time, the expiration of the preset time causing the device to transfer from the dynamic mode to a static mode where each of the plurality of light sources are simultaneously illuminated. The device also includes a plurality of selector elements each coupled to the input power line and a different one of the plurality of counter outputs, each of the plurality of the selector elements having an output connected to an input of a different one of the plurality of delay circuits, each selector element causing power to be passed to the delay circuit to which it is attached for a time period determined by the counter output connected to it. 
         [0007]    An aircraft comprising a device for forming a dynamic image on an aircraft sign is also disclosed. The device includes a plurality of light sources, an input power line, a first timer and a second timer both connected to an enable input and a plurality of delay circuits each connected to a different one of the light sources. The device further includes a counter having a plurality of counter outputs, the counter receiving a counting pulse from the first timer in a dynamic mode of operation and disable signal from the second timer after expiration of a preset time, the expiration of the preset time causing the device to transfer from the dynamic mode to a static mode where each of the plurality of light sources are simultaneously illuminated. The device also includes a plurality of selector elements each coupled to the input power line and a different one of the plurality of counter outputs, each of the plurality of the selector elements having an output connected to an input of a different one of the plurality of delay circuits, each selector element causing power to be passed to the delay circuit to which it is attached for a time period determined by the counter output connected to it. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The subject matter which is regarded as the present disclosure is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the present disclosure are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
           [0009]      FIGS. 1A and 1B  are examples of prior art aircraft exit signs; 
           [0010]      FIG. 2  is a partial cross section of an aircraft including an illustration of a sign above the aisle near the Exit Door that may operate in accordance with some embodiments described herein; 
           [0011]      FIG. 3  is circuit diagram of an example control circuit that may be utilized in combination with a sign such as the sign shown in  FIG. 2 ; and 
           [0012]      FIG. 4  shows different examples of signs in dynamic and static modes. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    In accordance with embodiments of the disclosure, device and system for active (e.g., dynamic) indicator signs are provided. 
         [0014]    In one embodiment, the dynamic sign includes multiple small chambers with one or more separately controllable LED lights therein. The LED lights are controlled by a driver circuit such that the instructions (e.g., the arrows) are dynamic. The dynamic nature may be provided by selectively energizing and controlling the brightness of the LEDs with a customized driver circuit. In particular, when the lights sign is in a dynamic mode, LED light intensity is turned down and up in sequence to animate the movement of the light which will instruct the passenger clearly. When the dynamic mode is not activated the circuit may control the sign just like existing static signs. 
         [0015]    Referring to  FIG. 2 , a partial cross-section of an aircraft  200  is shown. In  FIG. 2 , the aircraft  200  includes an internal wall  202  that is shown as a ceiling but the wall  202  could be a side wall in one embodiment. Herein, the internal wall  202  may be referred to as an aircraft ceiling or passenger compartment ceiling. The wall  202  is not, however, limited to being the highest portion of the passenger compartment and could located, for example, below an overhead baggage compartment of the passenger compartment or extend from a side or other wall of the aircraft  200 . 
         [0016]    The wall  202  is shown supporting an informational sign  204  by an optional support member  206 . The support member  206  may be omitted in one embodiment. Further the shape of the support member  206  can be varied and may be formed by screw or other fastener that couples the sign  204  to the wall  202 . While shown on an upper surface of the sign  204 , the support member  206  could be on the side or bottom of the sign  204 . Furthermore, the support member  206  is shown as a single element but it shall be understood that it may be comprised of multiple elements. 
         [0017]    The sign  204  may include a text region  220  that delivers a message to one or more passengers within the aircraft  200 . As illustrated, the message in the text region  220  is “EXIT” but other messages could be provided. The sign  204  also includes one more active or dynamic regions  240 . As illustrated, the sign  204  includes a first dynamic region  240   a  and second dynamic region  240   b . As more fully described below, a control element  208  will cause LED&#39;s or other light sources located behind the dynamic regions to alternatively turn on or vary in brightness. 
         [0018]    As illustrated, the first dynamic region  240   a  includes a plurality of lenses  210 - 218  carried by the sign  204 . One or more light sources (e.g., LED&#39;s or other light emitting devices) or are disposed behind the plurality of lenses  210 - 218 . The light sources are generally shown by elements  250 - 258 . It shall be understood that more light sources could be added behind each lens or that not every lens includes a light source behind it and that adjacent lenses may “share” light sources. 
         [0019]    In one embodiment, the exit sign  204  may include multiple chambers for the LEDs an may only have one Lens or diffuser which will cover all the chambers. Generally the lens or diffuser and its color and size will match with the FAR regulations. This lens/diffusor will allow light coming from the plurality of LEDs to animate the arrow only in intended places where the diffuser is opaque (Not completely transparent) and rest of the places may not allow the light to pass thru. Cambers  252  till  258  in  FIG. 2  will not be visible when the sign is operating in static mode due to the opaqueness of the lens/optical diffuser. 
         [0020]    In operation, the control unit  208  may cause either light sources  250 - 258  to turn on, then turn off when the next sequential light source is turned on. For example, in one embodiment, light source  250  is turned on and illuminates lens  210 . Then light source  250  is turned off and light source  252  is turned on and illuminates lens  212 . Similarly, light source  252  is turned off and light source  254  is turned on and illuminates lens  214 , light source  254  is turned off and light source  256  is turned on and illuminates lens  216  and so on until the last light source (e.g., light source  258 ) sequentially arranged in direction A is reached. In one embodiment, after light source  258  is turned off, light source  250  may be turned on again. In this manner, a repeating and moving directional arrow may be formed in dynamic area  240   a . Of course, the same or opposite operation could also be performed in the other dynamic area  240   b.    
         [0021]    In another embodiment, rather than just turning each light source on and off, each may be respectively ramped from a low power to a high power and then allowed to return (e.g., decay) to a low power. For example, in one embodiment, light source  250  initially at “0” power. This power is then ramped up to a peak value. After the peak value is reached (or near that time) the “next” light source  252  is then powered up. Similarly, light source  252  allowed to decay and light source  254  is ramped up and illuminates lens  214  until light source  254  begins decaying and light source  256  is turned on and illuminates lens  216  and so on until the last light source (e.g., light source  258 ) sequentially arranged in direction A is reached. In one embodiment, after light source  258  is turned off or starts to decay or reaches a specified power level, light source  250  may be turned on again. In this manner, a repeating and moving directional arrow may be formed in dynamic area  240   a . Of course, the same or opposite operation could also be performed in the other dynamic area  240   b . It shall be understood that the event that causes the next light source to be turned may be independent of the operation of a prior sequential light source. For example, a timer or delay circuit could be used. The rate at which a particular light source turns off could be controlled, for example by a switch (e.g., instant off′) or a decay circuit such as an resistor-capacitor (RC) circuit. 
         [0022]      FIG. 3  shows an example of a circuit  208  that may be used to control the sign  204 . In this example, the dynamic operation of the sign  204  may be due to providing delayed pulses to light sources that are shown as LEDs. Of course other light sources could be used. A timing diagram  340  showing the “on” times for the “n” diodes D 0 -Dn for each of the LED&#39;s is arranged directly next to the LEDs. For example, LED D 0  is emitting light for a two second period. The light ramps up and then decays as illustrated by trace  350 . As illustrated, each successive LED begins to ramp up 0.5 seconds after the previous LED. It shall be understood that D 0  will then begin to ramp again 0.5 second after the last LED (Dn) has started to ramp up. While illustrated as having a 0.5 second ramp up and 1.5 second decay, if shall be understood that trace  350  (or any other trace in graph  340 ) could have different characteristics. The particular characteristic may be selected by an input circuit. The illustrated input circuits for D 0  is a serial RC circuit but other types of input circuits could be used. In the event that an RC circuit is used, the resistance and capacitance values can be selected to achieve the desired rise and fall times (in this case, a 0.5 second rise is followed by a 1.5 second decay). The following discussion assumes that the input circuits are RC circuits and, thus, each input circuit is labeled “RCx”. Also, herein, the number of diodes and input circuits can be varied from 2 to n depending on the context and the eight shown in  FIG. 3  are merely an example. 
         [0023]    In operation, each input circuit RCx receives a sequentially applied logical high voltage (provided by the Power connection). That is, the first input circuit RC 0  receives a first pulse for a first time period (e.g, 0.5 seconds) and then the next input circuit RC 1  receives a pulse for the same time period and so on. The application of the pulses can be provided by the combination of a counter  306  driven by a dynamic operation clock  302 . Upon receipt of an enable (EN) signal, the dynamic operation clock  302  (which may be any type of digital clock) begins to provide a periodic clock pulse via line  310  to counter  306 . In this example, the counter  306  sequentially activates (e.g., drives to a logical “1”) each of its output. Each output is connected to a different on of plurality of selector elements  320 . The selector elements  320  are connected to power and when they receive a logical 1 its input, it allows power to flow to the input circuit connected to its output. In this example, input circuit RC 0  is connected to the output of selector element  320   a , input circuit RC 1  is connected to the output of selector element  320   b , input circuit RC 2  is connected to the output of selector element  320   c , input circuit RC 3  is connected to the output of selector element  320   d , input circuit RC 4  is connected to the output of selector element  320   e , input circuit RC 5  is connected to the output of selector element  320   f , and input circuit RC 6  is connected to the output of selector element  320   g , input circuit RCn is connected to the output of selector element  320   h . In one embodiment, the selector element is an AND gate but the skilled artisan will realize that other elements could be used. Further, it shall be understood that the rate at which the counter  302  pulses will set the rate at which each successive diode is illuminated as well as how long power is supplied to the diode. In one embodiment, the dynamic operation clock  302  provides a 2 Hz pulse to the counter  306  and counter  306  is an n-bit ring counter. In the example shown in  FIG. 3  the counter  306  may be an 8-bit ring counter. 
         [0024]    In one embodiment, an optional second or cutoff clock  304  is provided. This clock begins counting when the dynamic operation clock begins. The clock or timer  304  counts for a preset time period (e.g., 30 seconds). After that time, the timer  304  disables counter  306  via a signal connection  308  and causes override selector  320  to allow power to be constantly provided to only D 0  and the illumination elements that light the letters for “EXIT”. Thus, after the present time period the sign  204  of  FIG. 2  operates in the same manner as a static sign and light source  250  and Respective light source in  240   b  arrangement are ON all the time and at the same intensity. 
         [0025]    Examples of signs in the dynamic and static modes are shown in  FIG. 4 . In the dynamic mode, one or more arrows may be illuminated and in the static mode, only one arrow is illuminated. 
         [0026]    The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). 
         [0027]    While the present disclosure has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, the present disclosure can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the present disclosure. Additionally, while various embodiments of the present disclosure have been described, it is to be understood that aspects of the present disclosure may include only some of the described embodiments. Accordingly, the present disclosure is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.