Abstract:
An apparatus and method are provided to spatially multiplex information into a rainbow spectrum by filtering out certain frequencies or colors of the spectrum. The frequencies that are filtered or blocked out may depend on a value of a system input such as a level indicator, temperature gauge, pressure indicator, and the like. The spectrum, absent the filtered out frequencies, is sequentially focused into a single composite beam for transport through an optical path or fiber. Upon arrival to a destination, the composite beam is spatially separated into the original rainbow spectrum and projected onto a display. A viewer may subsequently view the spectrum and any dark areas within the spectrum associated with filtered or blocked frequencies and may, therefore, monitor a remotely located system.

Description:
BACKGROUND  
         [0001]    1. The Field of the Invention  
           [0002]    The present invention relates to the frequency multiplexing, transmission, display and use of physical position information sent via frequency-multiplexed light beams.  
           [0003]    2. Background  
           [0004]    Frequency multiplexing has traditionally involved the production of multiple carrier frequencies modulated with information to be retrieved at the receiver by separation and demodulation of independent channels. Whether the technique is used with radio, microwave, or light, the process is basically the same. Except in the case where specific information has been assigned to specific channel positions, such as television video, chromatic information and audio, the channel positions within the spectrum have no special significance. A television station can just as easily broadcast on one channel as another.  
           [0005]    Despite the commonly accepted beauty of a rainbow or prismatic dispersion, little practical value has been found in them. No method or apparatus provides a utility for the separation of colors as a means of direct transfer of information. No remote transmission of information has been found, nor any display using the same light for both transmission and ultimate projection for viewing. Meanwhile, neither is the phenomenon used for direct frequency multiplexing of information.  
         BRIEF SUMMARY AND OBJECTS OF THE INVENTION  
         [0006]    In view of the foregoing, it is a primary object of the present invention to provide an apparatus and method of multiplexing spatial information. It is another object of the invention to provide a visual display of spatial multiplexed information. It is another object of the invention to provide color-coded spatial information. It is yet another object of the invention is to provide spatial information that can be transmitted and received without the negative environmental effects that affect electronic methods.  
           [0007]    The foregoing objects and benefits of the present invention will become clearer through an examination of the drawings, description of the drawings, description of the preferred embodiments, and claims that follow.  
           [0008]    When information is transmitted via light, the same information can be transmitted using any color (e.g. blue light, red, etc.). The visible range is capable of containing many independent channels.  
           [0009]    Particular bands of frequencies within a spectrum have physical relationships not hitherto exploited. Unexploited physical relationships include the “physical” positioning of energy from individual channels at locations within a dispersed spectrum, with respect to each other. Such physical positioning may result when the energy in the spectrum is directed through a diffraction system such as a prism or diffraction grating.  
           [0010]    Using a prism with the visible band of light as an example, red is always positioned next to yellow, then green, then blue, then violet. The prism never performs otherwise. It cannot be physically confused. The colors always maintain these spatial positions. Moreover, the rainbow of color remains substantially contiguous if the light-source spectrum is substantially contiguous. Many light sources such as an incandescent bulb, for example, produce a multitude of spectral lines, close enough together to produce a spectrum considered substantially contiguous.  
           [0011]    The present invention exploits the physical relationship that frequency-multiplexed information assumes as a result of separation by a diffraction system (e.g. prism, diffraction grating, etc.). At an information transmission site, a dispersed (spatially separated) spectrum illuminates a masking area. A movable mask may be placed in or moved about in the masking area to block (i.e. absorb, reflect, divert, etc.) or pass through (i.e. transmit) energy of various frequencies. Blocking depends upon the physical position of the mask relative to the physical positions of the various colors (i.e. frequency channels) within the dispersively illuminated masking area.  
           [0012]    A transmitter may essentially be a mechanically-controlled (e.g. pneumatic, hydraulic, electric, and the like) optical bandpass filter. The “filter” passes a band of frequencies controlled by the position of the mask. The mask may be positive (selectively transmitting) or negative (i.e. selectively blocking).  
           [0013]    Unmasked light may be gathered together using lenses, prisms, mirrors or other optical elements. Light may be directed or focused into a composite beam for transmission, usually by directing the composite beam into an optical fiber.  
           [0014]    As a mask is moved by some actuating mechanism (e.g. sensor, gauge, thermometer, and the like), the position of the mask is spatially and frequency-multiplexed into the composite beam. Each frequency channel (color) is illuminated (or darkened) in sequence as a mask is moved along the spatially distributed colors of the spectrum. As a result, a relationship may be established between a position of a mask and particular frequencies. Whether energized or not, frequency-multiplexing spatial information may be embodied in the composite beam, yielding positional or spatial multiplexing.  
           [0015]    A remote destination device (receiver) may be as simple as a diffraction mechanism such as another prism or diffraction grating along with a display screen, which the light is projected onto or through for viewing. The spatially multiplexed composite beam received from the optical fiber is directed through this remote display prism to produce a remote illuminated area on the display screen.  
           [0016]    A prism reorganizes and repositions (distributes) available bands of energy into a spectral display. Colors have the same relative positions as within the illuminated masking area of the transmitter, and thus the frequency-multiplexed information is displayed as spatially-related information within a displayed spectrum. Displayed position, color, or both may indicate the position of the mask back at the transmitter.  
           [0017]    For example, the mask may be a simple thin bar or indicator needle that blocks only a small band within the illuminating spectrum at the masking area. The remote display may include an incomplete rainbow spectrum lacking certain colors. A dark line will exist at any channel position blocked out by spectral masking by a needle or other mask located anywhere between the display and the transmitter where the light has been dispersed. As the needle is moved relative to the dispersed spectrum in the masking area, different parts of the spectrum are filtered out (blocked) by the mask. In the display, a dark line in the spectrum (an absence of those corresponding colors) moves along the rainbow to indicate directly a position of the mask (needle).  
           [0018]    One unique quality of an apparatus in accordance with the present invention may be manifest by a comparison of the organization of energy within both the illuminated masking area and the remote illuminated area and within the composite beam transmitting between the two illuminated areas. In the two illuminated areas, the energy content is organized spatially into rainbow spectra. However, in the composite beam, no spatial organization exists. While some of the color channels may be energized and other color channels may not, the energy essentially occupies the same space within the optical fiber as it travels through the fiber. Only when the energy is spatially reorganized by a display prism or diffraction grating are the spatial relationships of the various frequency channels revealed. Thus, the frequency multiplexing of spatial information that takes place in the transmitter is (demultiplexed and displayed at the receiver.  
           [0019]    Likewise, the position of the needle mask is indicated by the position of adjacent energized and de-energized channels, which have been displayed by prisms and/or diffraction gratings, and the like. This is due to the fact that the receiver organizes the available energy in the same spatial relationships as received from the transmitter, whereas, in the composite beam, the spatial information of the needle mask is indistinguishable from the rest of the beam.  
           [0020]    For example, one application in accordance with the invention may include a thermometer, whereby a dark line within the rainbow spectrum may indicate a temperature. As the temperature changes, the position of a masking needle may change relative to various channels within an illuminating spectrum at a transmitter, turning adjacent channels (colors) progressively on or off Consequently, the dark line within a displayed spectrum may move relative to the displayed spectrum, indicating the temperature. When the temperature changes in a certain direction, the dark line may move toward the violet end of the displayed spectrum. Conversely, as the temperature moves in an opposite direction, the dark line may move toward the red end of the displayed spectrum (or vice versa).  
           [0021]    Likewise, other useful applications may be implemented in accordance with the invention. For example, spatially-multiplexed composite beams can be routed from transmitter to receiver using optical fibers or any other structure for directing beams from one place to another. Consequently, the information from a temperature sensor on an aircraft engine may be routed through an airframe to a cockpit using optical fibers. There, the position of a thermometer needle may be displayed directly as a dark line in a rainbow spectrum using energy that has traveled directly from an engine. However, unlike traditional methods, the process only requires the use of a light-weight optical fiber, rather than a bundle of copper wires.  
           [0022]    Unlike electro mechanical remote sensing methods currently used in automobiles and aircraft, the present invention may not require calibration other than aligning the position of the displayed spectrum with any numbers or marks on the display screen. Whereas temperature and other environmental factors can affect the calibration of electrical systems by changing the resistance in transmission wires, the present invention is immune to such changes. A fiber optic cable may be curved or bent, but the spectrum, while it may vary in intensity, will still be visible. Moreover, bending of an optic fiber will not change the spectrum of a transmitted beam and thus will not alter the displayed position of the needle or within the spectrum. In instances where weight is critical, applications of the present invention may be constructed of lightweight materials such as plastic, as opposed to heavy copper wire and servo motors used in conventional remote sensing and display equipment.  
           [0023]    Another characteristic of the present invention is that a variety of mask shapes may be used to produce a variety of displays. The mask may also be constructed with a slot that allows only a narrow band to pass, or a solid mask with its edge acting as an indicating position. This may be implemented so that the bandpass is made wider or narrower depending on the position of the mask edge.  
           [0024]    Accordingly, with proper selection of an appropriate mask shape, spatially multiplexed information from the composite beam may also be viewed directly as color-coded information without the use of a remote prism. Also, in certain embodiments, multiple moving masks may be used in distinct portions of the spectrum to transmit information from multiple sources.  
           [0025]    As a practical matter, a variety of mechanical arrangements for accomplishing spatial multiplexing, including the implementation of colored filters as a mask or movable light sources that replace the mask, may be implemented. Although the present disclosure uses optical terminology and components, the present invention may operate using any substantially contiguous band of the electromagnetic spectrum and is not limited to visible light (except when direct viewing is required).  
           [0026]    In accordance with the invention, the method or process of spatially multiplexing information at the transmitter may be summarized in the following steps: (1) providing multifrequency electromagnetic energy spatially separated in frequency as a substantially contiguous spectrum illuminating a masking area; (2) providing a movable mask or masks positioned and oriented to mask at least one portion of the masking area; (3) combining non-masked electromagnetic energy from the masking area into at least one composite beam; (4) moving one of the movable masks to various positions along the masking area, changing the composite frequency content of the composite beam (depending upon the position of the movable mask), thereby multiplexing spatial information about the movable mask into the composite beam; and (5) using an optical waveguide to carry the composite beam to a remote receiver (optional) to extract the spatial information of the composite beam.  
           [0027]    Accordingly, extraction of spatial information at the receiver requires directing the composite beam to at least one remote device having a structure for separating the composite beam into a remote illuminated area, having different positions for different frequencies of the multifrequency electromagnetic energy. Thus, the receiver provides the spatial information relative to the remote illuminated area by illuminating the different positions as energy is available from the composite beam, which is controlled by the movable mask.  
           [0028]    Production of a visible display can include these additional steps: First, to use visible light as said electromagnetic energy, and second, to position and orient said remote illuminated area so that it can be viewed, providing a remote display of said spatial information. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0029]    The foregoing and other objects and features of the present invention will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only typical embodiments of the invention and are, therefore, not to be considered limiting of its scope, the invention will be described with additional specificity and detail through use of the accompanying drawings in which:  
         [0030]    [0030]FIG. 1 is a schematic block diagram of an apparatus and method in accordance with the invention of a rainbow display;  
         [0031]    [0031]FIG. 2 is a schematic of one embodiment of a rainbow display apparatus in accordance with the invention;  
         [0032]    [0032]FIG. 3 is a diagram of one embodiment of a spectrum display in accordance with the invention;  
         [0033]    [0033]FIGS. 4 a - 4   c  are diagrams of several embodiments of spectrum masks in accordance with the invention;  
         [0034]    [0034]FIG. 5 is a diagram of one embodiment of a spectrum masking device using a bimetallic spring;  
         [0035]    [0035]FIG. 6 is a schematic diagram of a fluid level indicator demonstrating one possible implementation of the rainbow display apparatus in accordance with the invention;  
         [0036]    [0036]FIG. 7 is a schematic diagram of a temperature gauge demonstrating one possible implementation of the rainbow display;  
         [0037]    [0037]FIG. 8 is a schematic diagram of a pressure indicator demonstrating one possible implementation of the rainbow display;  
         [0038]    [0038]FIG. 9 is a schematic block diagram of one embodiment of a rainbow display implementing a beam deflector to deflect a single frequency light beam;  
         [0039]    [0039]FIG. 10 is a schematic diagram of one embodiment of a broad spectrum light separator implemented in conjunction with a movable channel receiver configured to receive a single frequency of light;  
         [0040]    [0040]FIG. 11 is a diagram of a rotatable light separator for possible implementation in a rainbow display apparatus;  
         [0041]    [0041]FIG. 12 is a diagram of one embodiment of a pivotable mirror configured to direct determined light frequencies into a waveguide;  
         [0042]    [0042]FIG. 13 is a diagram of a pivoting mirror configured to direct determined light frequencies into an optic fiber or other reception channel;  
         [0043]    [0043]FIG. 14 is a diagram or a movable array of frequency-distinct light sources configured to pass a single light frequency through an opening in a mask for transmission to a display;  
         [0044]    [0044]FIG. 15 is a schematic diagram of one embodiment of a rainbow display apparatus wherein the broad spectrum light source is located near the receiver or display;  
         [0045]    [0045]FIG. 16 is a schematic diagram of a display configured to display only one frequency of visible light; and  
         [0046]    [0046]FIG. 17 is a diagram of several possible embodiments for colored light or rainbow spectrum displays in accordance with the invention; 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]    It will be readily understood that the components of the present invention, as generally described and illustrated in the Figures herein, could be arranged and designed in a wide variety of different configurations. Thus, the following more detailed description of the embodiments of the system and method of the present invention, as represented in FIGS. 1 through 17, is not intended to limit the scope of the invention. The scope of the invention is as broad as claimed herein. The illustrations are merely representative of certain, presently preferred embodiments of the invention. Those presently preferred embodiments of the invention will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout.  
         [0048]    Those of ordinary skill in the art will, of course, appreciate that various modifications to the details of the Figures may easily be made without departing from the essential characteristics of the invention. Thus, the following description of the Figures is intended only to be exemplary, and simply illustrate several presently preferred embodiments that are consistent with the invention as claimed.  
         [0049]    Referring to FIG. 1, a block diagram for a rainbow display apparatus in accordance with the invention may include a broad spectrum light source  12  energized by a power source  14 . That is, a power source  14  may energize a light source  12  configured to generate visible light in one composite beam  26  containing the full continuum of colors contained in visible white light (red through violet). The composite beam  26  is passed to a beam separator  16 , wherein the individual light frequencies (colors) are spatially separated into a rainbow spectrum. The rainbow spectrum is sequentially passed through a filter  18  wherein certain frequencies or colors are filtered (i.e. blocked) out as controlled by some system input  20 .  
         [0050]    Subsequently, the individual rainbow spectrum frequencies, absent the filtered or blocked out frequencies, are recombined by a focusing element  22  into a composite beam  28 , or a beam  28  wherein all remaining light frequencies are combined or mixed. The composited beam  28  is then passed to an output display  24  wherein the composite beam  28  is spatially separated and displayed as a rainbow of colors, absent the colors or frequencies removed in the filtering process. Thus, the output display  24  may display a dark area where the frequencies were blocked out by the filter  18  controlled by the system input  20 . Such a system may be advantageous to monitor a remote event or process and may eliminate the need for many parts used in typical gauges and displays.  
         [0051]    Referring to FIG. 2, one embodiment of a rainbow display apparatus may comprise a broad spectrum light source  12 , which transmits a composite beam  26  through a channel  52  or optic fiber  52 . Upon leaving the channel  52 , the beam  26  may be spatially separated by a prism  56  or diffraction grating  56  into a rainbow spectrum  58 . Subsequently, a mask  60  or filter  60  actuated by an input system blocks a portion of the spectrum  58 . The remaining spectrum  59  may then be recombined into a single composite beam  28  by a focusing element  64 , which may comprise a plurality of prisms, lenses, and the like. The composite beam  28  may be transmitted through a channel  54  or optic fiber  54  until it exits the channel  54  and is spatially separated by a separating element  66  or lens  66  and projected onto a display  62 . A dark spot will appear in that portion of the rainbow spectrum  59  that is blocked by the filter  60  or mask  60 .  
         [0052]    Referring to FIG. 3, one embodiment of a display  106  or viewer  106  may display a spectrum  108  of colors. Such a display  106  or viewer  106  may be used as a gauge or indicator in the cockpit of an airplane or the cabin of an automobile. For example, a rainbow spectrum may contain red at one end  110  and violet at the other end  112 . Likewise, any other range of contiguous values of visible colors as contained in white light may be used as the spectrum  108 . A dark line  102  or gap  102  may appear corresponding to the frequencies filtered or blocked out by a mask  60 . Accordingly, a scale  104  may be calibrated using specific marks on the display  106 , which in turn will give meaning or value to the location of the dark line  102  or gap  102 . The exact layout or configuration of the display  106  may comprise numerous shapes and forms and need not be limited to the configuration illustrated.  
         [0053]    Referring to FIGS.  4 A- 4 C, several alternative mask shapes and configurations are illustrated for use as filters in accordance with the invention. For example, in FIG. 4A, a solid mask  156  may be implemented wherein the mask edge  162  is used to block out portions of the spectrum  58  contained in the mask area  152 . The mask edge may be moved in the directions  164 ,  166 , and thus block out differing amounts of the spectrum  58 . Accordingly, the viewer would observe a lower (or upper) portion of the spectrum  58  as a dark area on the display  106 , as described previously.  
         [0054]    Likewise, in another embodiment, a needle mask  154  may be used in conjunction with the aforementioned solid mask  156  as illustrated in FIG. 4A. Consequently, multiple independent sources of information may be multiplexed into the same composite beam  28  (described previously) and shown on a common display  24 . For example, the needle mask may move in the directions  164 ,  166 , representing one system input, and the mask  156  may also move in the directions  164 ,  166 , representing another system input.  
         [0055]    In yet another embodiment, a mask  160  with a slot  158  may be moved across a masking area  152  in the directions  164 ,  166  as illustrated in FIG. 4C. As a result, all portions of the spectrum  58  except those exposed by the slot  158  will be blocked or filtered. An embodiment of this configuration may be used to pass a single frequency of light to a display  24  to notify a viewer of some system response or state.  
         [0056]    Referring to FIG. 5, an application for use with the present invention may include a bimetallic spring  202 , which expands or contracts in response to changes in temperature. The spring may be configured to actuate an arm  204  connected to a needle mask  154 , which moves in the directions  164 ,  166 . As described previously, the needle mask  154  moves across the mask area  152 , blocking portions of the spectrum  58 . Such a mechanism may be implemented in a temperature gauge in accordance with the invention.  
         [0057]    Referring to FIG. 6, an application of the rainbow display apparatus may be implemented in conjunction with a level indicator. As illustrated, a tank  252  may contain a liquid  254  or fluid  254  at a level  256 . An adjoining measurement compartment  260  may be connected to the tank  252  by a channel  258  such that the levels  256 ,  262  are equal. As the level  256  rises or falls, the level  262  will correspondingly rise or fall and move a level indicator  264  or float  264 , which may be used to actuate a mask or filter in accordance with the invention.  
         [0058]    Referring to FIG. 7, a further application of the rainbow display apparatus may be implemented in conjunction with a temperature gauge. A first metal  302  may be joined to a second metal  304 , each of the metals having a different coefficient of thermal expansion. That is, for any increase or decrease in temperature, the first metal  302  will expand by a larger or smaller amount than the second metal  304 , causing the joined metals  302 ,  304  to bend or curve. Consequently, an indicator  306  attached to the joined metals  302 ,  304  will move in the directions  308 ,  310 . Like the previous examples hereinbefore discussed, the indicator  306  may be implemented to actuate a mask or filter in accordance with the invention of the rainbow display apparatus.  
         [0059]    Referring to FIG. 8, yet a further application of the rainbow display apparatus may be used in conjunction with a pressure indicator. A container  352  or receptacle  352  may contain a pressurized gas or liquid that exerts force on a piston  354  or diaphragm  354 . The piston  354  or diaphragm  354 , in turn, exerts a force compressing a spring  356  actuating an arm  358 , which moves in the directions  360 ,  362 . The arm  358  may be used to actuate a mask or filter to be used with the present invention of the rainbow display apparatus.  
         [0060]    Referring to FIG. 9, one embodiment in accordance with the invention may include a broad spectrum light source  12 , which transmits a composite beam  26  through a channel  52 , such as an optic fiber  52 . A beam deflector  404  receives the beam  26  and separates the composite beam  26  into spatially separate colors or frequencies. Meanwhile, the beam deflector  404  receives an input signal  402  (e.g. electrical or mechanical) and transmits one of the colors or frequencies into the channel  54 , depending on the value of the system input  402 . Thus, a particular color  406  or frequency  406  will be transmitted for viewing on a display screen  24 , depending on some external system input  402 . An embodiment of this configuration may be useful when a single color  406  or frequency  406  is desired to monitor the state of some remote system.  
         [0061]    For example, the beam deflector may be configured to transmit the color red when a system is in a critical state, yellow for a cautionary state, or green for a favorable state.  
         [0062]    Referring to FIG. 10, one embodiment is illustrated for the beam deflector  404  of FIG. 9, wherein only one color is desired for display. A broad spectrum light source  452  may transmit a composite beam to a light diffractor  456  or beam separator  456 , which spatially separates the beam into the rainbow spectrum  454 . A channel  460  may be configured to move in directions  464 ,  466  to receive only a single color  462  or frequency  462  to be transmitted to a display device.  
         [0063]    Referring to FIG. 11, one alternative embodiment for the beam deflector  404  of FIG. 9 for use in the present invention may comprise a prism  472  that rotates on a shaft  474 . As a result, the angle of deflection of any color or frequency may be controlled by rotating the shaft  474 , which may be controlled by some external system input  402 .  
         [0064]    Referring to FIG. 12, another alternative embodiment for the beam deflector  404  for use in the present invention may comprise a broad spectrum light source  452 , which transmits a beam through a prism  498  or beam separator  498  into a rainbow spectrum  454 . A mirror  494  may be configured to pivot about a shaft  496  and reflect certain bands of frequencies of the rainbow spectrum  454  into a waveguide  492 , depending on the angle of the mirror  494 . Thus, the angle of the mirror  494 , and therefore, the transmitted bands or frequencies, may be controlled by some external system input  402  as illustrated in FIG. 9.  
         [0065]    Referring to FIG. 13, yet another alternative embodiment for a beam deflector  404  may comprise a broad spectrum light source  452 , which may transmit a beam through a prism  456  or beam separator  456  into rainbow spectrum  454 . A mirror  494  may be configured to pivot about a shaft  496  and deflect a single color  462  or frequency  462  into a channel  460  or optic fiber  460 . Similar to the previous examples, the angle of the mirror  494 , and thus, the transmitted color  462  or frequency  462 , may be controlled by an input  402  from an external system.  
         [0066]    Referring to FIG. 14, another alternative embodiment for transmitting a single color  462  or frequency  462  may comprise a movable array  536  of distinct light sources emitting different colors or frequencies. The array  536  may be positioned behind a mask  534  or filter  534 , which may block all light frequencies except a single color  538  or frequency  538 , which is allowed to pass through an opening  532  in the mask  534 . The array  536  may move in the directions  540 ,  542 , or alternately, the mask  534  and channel  460  may be configured to move with respect to the array  536 . Thus, a single color  462  or frequency  462  may be transmitted to a display through a channel  460  or optic fiber  460 . Such an arrangement, would allow an arrangement of light sources  536  to be ordered in any desired sequence, and would not limit the ordering to that occurring in the natural rainbow spectrum.  
         [0067]    For example, in the natural rainbow spectrum, the lowest visible light frequency starts at red and continues through the colors orange, yellow, green, and the like until the frequency for violet is reached. However, when using an array  536  of light sources, wherein each light source  538  may emit a single color or frequency, the lights  536  may be arranged in any order desired and certain frequencies may be omitted if such frequencies are not used, or rearranged to display colors  538  or frequencies  538  in a selected order. Therefore, this embodiment may provide an increased degree of flexibility to design specific gauges, displays, sensors, thermometers, and the like.  
         [0068]    Referring to FIG. 15, sometimes it may be more convenient to have a light source  452  located at the receiving end rather than at the transmitting end of a rainbow display apparatus in accordance with the present invention. FIG. 15 illustrates one embodiment in which a composite multicolored beam is transmitted through a channel  554  or optic fiber  554  wherein the beam is spatially multiplexed, only to return back to the receiving end for display.  
         [0069]    Light source  452 , which produces broad spectrum light, may be directed by optical apparatus through a beam splitter  552 , such as a half-silvered mirror  552 , along a path  562   a  into a channel  554  or an optical fiber  554 . The multifrequency light may exit the optical fiber  554  and may be spatially separated by a separator  556 , such as a lens  556  or prism  556 , and may be projected through a mask area defined by a plane  559  having a needle mask  558 . Unmasked light may be reflected from a mirror  560 , such as a parabolic mirror  560 , back into the lens  556  or prism  556 . The remaining colors or frequencies may subsequently be recombined into a composite beam  562   b  and transmitted back through the optical fiber  554  along a path  562   b  or light beam  562   b . Light beam  562   b  may be routed by the mirror  552  to a separating element  564 , such as a lens  564  or prism  564 , and separated into a rainbow spectrum  570  (absent the blocked out frequencies) onto a display  566 . Thus, both the light source  452  and the display  566  are positioned at the same end of the transmitting fiber  554 .  
         [0070]    Referring to FIG. 16, an embodiment for a display apparatus that uses only a single color or frequency is illustrated. A single color  602  or frequency  602  may be transmitted through a channel  604  or an optical fiber  604  to a dispersing element  606 , such as a lens  606 . Such a dispersing element  606  may spread or distribute the single frequency energy  608  over an area and onto a display  610  for viewing by a user  612 .  
         [0071]    Referring to FIG. 17, lighted symbols or special shaped displays may be implemented to provide particular information to the viewer by properly positioning and orienting various translucent symbols on an opaque background  658 . Red light, for example, may be directed to a stop symbol  652 . Likewise, yellow light may be directed to a caution symbol  654 , and green light to an OK symbol  656 . Alternatively, energy from the various parts of the sensor may be routed to new positions within a specially-shaped display. For instance, energy from a remote sensor may be directed into a semicircular shape with violet appearing at an end  660 , and continuing through the rainbow spectrum to red at another end  662 . A semicircle display  659  may also be calibrated so that a dark line may be interpreted based on a particular scale  664 .  
         [0072]    From the above discussion, it will be appreciated that the present invention provides a method for multiplexing spatial information by optical means using fewer mechanical parts than typical electrical gauges and sensors. The present invention predominantly relies on moving parts implemented in the transmitting end of the device instead of in the instrumentation of the display. Furthermore, the calibration of gauges may be greatly reduced by use of the present invention because colors or frequencies filtered out by the masking device will be exactly replicated when viewed on a display. The weight and danger inherent in electrical wiring may also be lessened by substituting an optical path, such as an optical fiber, for transmitting information.  
         [0073]    The present invention may be applied to various commonly used gauges and sensors such as level indicators, temperature gauges, pressure indicators, and the like. Likewise any system that may be employed to actuate a mask or colored lights may make use of the present invention to transmit information.  
         [0074]    Moreover, the present invention uses the colors of the rainbow spectrum to display information, therefor enabling color-coding of information. The present invention may make use of an entire spectrum, filtering out portions of the spectrum thereof, or may route only specified colors or frequencies to transmit information. Likewise, the display may use many colors of the spectrum or simply use a single color to notify a user of the status of some external system.  
         [0075]    The present invention may be embodied in other specific forms without departing from its structures, methods, or other essential characteristics as broadly described herein and claimed hereinafter. The described embodiments are to be considered in all respects only as illustrative, and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.