# Patent

## Title
Device having a casing and/or interior acting as a communication bus between electronic components

## Abstract

A device other than a projectile including: a casing, at least a portion of which contains a potting material acting as the optical waveguide material; a transmitter for transmitting a pulse based signal at least partially through the potting material; and a receiver for receiving the pulse based signal after one or more reflections of the pulse based signal from interior surfaces of the casing; the pulse based signal having a pulse rate configured such that a subsequent pulse doesn't interfere with reflections from an immediately previous pulse.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 11/899,731 filed on Sep. 7, 2007 which is a divisional application of U.S. application Ser. No. 10/639,001 filed on Aug. 12, 2003, now U.S. Pat. No. 7,272,293, the entire contents of which is incorporated herein by reference.


BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to devices, and more particularly, to devices having a casing and/or interior that act as a communication bus between at least two components of the device. For purposes of this disclosure, a device is any article having a casing which houses two or more electrical/electronic components. Also for purposes of this disclosure, a communication bus is anything that transmits one or more signals between two or more components. Such transmission may be one-way or two-way. Thus, the transmission may be a simple point-to-point link between two components or a point to many links between several components. Furthermore, the transmission may be such that the transmitted signal(s) are available to any components on the communication bus. Still further, the communication bus may be more than one media, such as a waveguide, potting material, and/or free space in the casing (including the casing itself).
2. Prior Art
Electronic devices typically have a casing or shell in which electronic/electrical components are housed. The electronic/electrical (collectively referred to hereinafter as “electronic” or “electronics”) components interact with each other and/or other devices via internal wiring (which includes printed circuit boards). While the wiring has its advantages, it suffers from certain disadvantages such as susceptibility to noise, brittleness, potential for high bit error, takes up a large amount of space in the interior of the casing or shell, can suffer from poor connections, and may be susceptible to impact and shock. These disadvantages are amplified in certain devices that house electronic components and operate in harsh environments.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide methods and devices that overcome the disadvantages of the wiring used to link components in devices having electronic components.
Accordingly, a device other than a projectile is provided. The device comprising: a casing, at least a portion of which contains a potting material acting as the optical waveguide material; a transmitter for transmitting a pulse based signal at least partially through the potting material; and a receiver for receiving the pulse based signal after one or more reflections of the pulse based signal from interior surfaces of the casing; the pulse based signal having a pulse rate configured such that a subsequent pulse doesn't interfere with reflections from an immediately previous pulse.
The potting material can be selected from a group consisting of a solid, a gel, and a liquid. Where the potting material is the solid, the solid can be an epoxy resin.
The signal can be an infrared signal.
The casing can include a window through which an input signal is transmitted from an exterior of the casing to at least one of the potting material and receiver.
Also provided is a method for transmitting signals between components in a device other than a projectile. The method comprising: filling at least a portion of the device with a potting material acting as an optical waveguide material; transmitting a pulse based signal at least partially through the potting material acting as the optical waveguide material; reflecting the pulse based signal from interior surfaces of the device; and receiving the pulse based signal after one or more reflections; wherein the pulse based signal has a pulse rate configured such that a subsequent pulse doesn't interfere with reflections from an immediately previous pulse.



BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
FIG. 1 illustrates a schematic view of a generic electronic device having a casing nose and two or more electronic components according to a first embodiment.
FIGS. 2A, 2B, and 2C illustrate sectional views of a wall of the casing of FIG. 1 as taken along line 2-2 in FIG. 2, FIGS. 2A, 2B, and 2C representing three alternative wall/waveguide configurations.
FIG. 3 illustrates a sectional view of a computer CPU casing according to an embodiment.
FIG. 4 illustrates a partial sectional view of a cellular telephone according to an embodiment.
FIG. 5 illustrates a partial sectional view of a cellular telephone according to another embodiment of the present invention.
FIG. 6 illustrates a schematic electrical diagram of an infrared (IR) transceiver for use with the cellular telephone of FIG. 5.
FIG. 7 illustrates a cellular telephone according to another embodiment of the present invention.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Although the invention is particularly suited to optical signal communication between electronic components, such is discussed by way of example only. Those skilled in the art will appreciate that other communication means can also be utilized, such as ultrasound. Further, although a generic casing, computer casing, and cellular phone casing are illustrated and discussed herein, such are given by way of example only, those skilled in the art will appreciate that the devices and methods of the present invention can be utilized in any device having an interior which houses at least two interconnected electronic components.
Referring now to FIG. 1, there is shown a generic device generally referred to by reference numeral 100. The generic device 100 has a casing 102 that defines an interior 104. The casing 102 preferably has a metal, plastic, or composite outer portion 106 and a communication bus, such as waveguide portion 108. The casing 102 is shown generically as rectangular in shape, however, those skilled in the art will appreciate that it may have any shape. Furthermore, the casing 102 is shown having a two-piece construction, upper shell 106a and lower platform 106b joined together with screws 107. However, those skilled in the art will appreciate that the casing 102 can be constructed from one or more pieces, and if more than one piece, the pieces can be joined or fastened in any manner known in the art, such as by welding, gluing, riveting, or with interference or snaps.
The waveguide portion 108 is preferably optical glass having appropriate cladding as is known in the art. However, the waveguide portion 108 can also be a synthetic material, such as an acrylic, polycarbonate, or epoxy. The inner waveguide material can be formed on the casing 102 by any methods known in the art, such as by casting, machining, or depositing. The waveguide portion 108 can be disposed on the entire inner surface of the outer portion 106 of the casing 102 (or a portion thereof) as shown in FIG. 2A. Alternatively, the waveguide portion 108 can be arranged in strips 117, formed on the outer portion 106 of the casing 102 as is shown in FIG. 2C, or in channels 111 formed in the outer portion 106 of the casing 102 as is shown in FIG. 2B. Alternatively, the waveguide portion 108 can make up the entire shell 102 (no outer portion 106 is used), which can be uncoated or have a coating, such as an opaque paint.
At least one transmitter 110 is arranged on the waveguide portion 108 or proximate thereto such that a signal 101, such as an optical signal can be transmitted to the waveguide portion 108. The transmitter 110 can be integral with a corresponding electronic component 112 or connected thereto. At another location on the waveguide portion 108 are located detectors 114 for detecting the optical signals in the waveguide portion 108. Each detector 114 is either integral with or connected to another electronic/electrical component 116. Thus, those skilled in the art will appreciate that any component can communicate with another component through the waveguide portion 108, which acts as a communication bus. Of course, each of the components can have both a transmitter 110 and detector 114 such that a two-way communication can be achieved. Furthermore, each of the transmitter and detector can itself be considered a component operatively connected to the waveguide portion 108 (communication bus). Although not shown, mutiplexers and demultiplexers can be used such that certain components can operate at selected frequencies and/or wavelengths and not interfere with other components on the bus. Similarly, other components known in the art for transmission of signals through a waveguide can be used, such as an amplifier (not shown) for amplifying a signal between components. The transmitters 110 and detectors 114 can be mounted to the waveguide portion 108 directly as is known in the art such as by an optical quality adhesive, as shown in FIGS. 2A and 2C. Alternatively, the transmitter 110 and detectors 114 can be mounted to the waveguide portion 108 or the outer portion 106 of the casing 102 by mechanical means, such as a bracket 113 and screws 115 as is shown in FIG. 2B. Also, the transmitters and detectors can be both adhered and mechanically fastened to the waveguide portion 108. As another alternative, the components can be connected to the waveguide portion 108 by optical fibers (not shown) or the like.
Those skilled in the art will appreciate that the interior 104 is not cluttered with components and internal wiring resulting in more components being able to occupy a given interior size or the device 100 being made smaller than a conventional device having the same number of internal components. In the device shown in FIG. 1, portion 104a of the interior 104 can be used to house additional components or the device can be reduced in size to eliminate portion 104a or a portion thereof. Other advantages include:
*The optical transmission provides robust, interference free channels between physically disconnected components/systems;
* The optical transmission is naturally resistant to very high g-loads and harsh environments;
*For shorter distances between the transmitter and receiver, the system is inexpensive and extremely low bit rate error (better than 10−12) can be readily achieved; and
*The need for wires and related problems and space requirements are eliminated.
Alternatively, ultrasound can be used to communicate between the internal components 112, 116. In which case, the casing 102 or a portion thereof needs to be able to carry an ultrasound signal between components. Such a casing 102, or portion thereof, may be constructed from a suitable metal. In the case of ultrasound, an ultrasonic generator is used to place signals on the “bus” (casing 102) and a corresponding ultrasonic detector detects the ultrasonic signals and relays them to an appropriate component. Of course, the casing may also be a synthetic material having portions of suitable materials for carrying an ultrasound signal. As discussed above with regard to the optical signal configuration, each component can have both an ultrasonic generator and detector such that two-way communication between components is possible and mutiplexers and demultiplexers can be utilized such that certain components can operate at selected frequencies and/or wavelengths and not interfere with other components on the bus.
In another embodiment, the casing 102 is a casing of a CPU of a computer 200. In yet another implementation, the casing 102 is a casing of a cellular telephone 300. As discussed above, such embodiments are given by way of example only and not to limit the scope or spirit of the present invention.
Referring now to FIGS. 3 and 4, there is shown a computer CPU 200 and cellular telephone 300, respectively, in which similar number series denote similar features to that of FIG. 1 (i.e., casing 102 corresponds with casings 202 and 302, etc.). Those skilled in the art will appreciate that the casings 202, 302 can be made smaller than a conventional counterpart device having the same number of internal components or be able to house more components in the same size casing. Thus, the present invention can provide a miniaturization of electronic devices, particularly portable electronic devices while eliminating the problems associated with wiring, such as signal speed, poor connections, and failure over time due to brittleness and other insulation failures. The waveguide portion 108 also provides for a flexible design and layout of the electronic components as well as the ability to easily add a component on the communication bus (waveguide portion 108) of the device. For example, where the waveguide portion 108 is deposited on a substantial portion of the inner surface of the casing 102, the electronic components can be distributed or added on any portion of the casing where the waveguide portion 108 is deposited.
Examples of other devices not shown which can benefit from the methods disclosed herein are PDA's (personal digital assistants), cordless telephones, VCR's, portable CD and MP3 players, digital cameras, DVD players, and televisions. Such a listing is given by way of example only and is not intended to be exhaustive of any other electronic devices. Although discussed as electronic components, such components can also have a mechanical or chemical function as well as an electronic/electrical function. These mechanical and/or chemical functions can be housed in a portion of the interior of the casing that has been freed up by having the electronic components distributed on the casing.
Referring specifically to FIG. 3, there is shown a computer CPU 200 having a casing 202 defining an interior 204. The casing has an outer portion 206 and a waveguide portion 208 that carries a signal 201. Transmitters 210 and detectors 214 are operatively connected to the waveguide portion 208 and mounted to respective electronic components 212, 216. Those skilled in the art will appreciate that the computer CPU 200 can be made smaller, particularly, thinner in height (H) than conventional CPU's that utilize conventional wiring between components. Alternatively, the computer CPU 200 can house more components than would be possible for a similarly sized CPU of the prior art that utilizes conventional wiring between components. Furthermore, the CPU 200 has a more versatile design and can be upgraded with additional components at any place on the waveguide portion.
Referring specifically to FIG. 4, there is shown a cell phone 300 having a casing 302 defining an interior 204. The casing also carries an antenna 305, a display 303, and a keyboard and other features (not shown). The casing 302 has an outer portion 306 and a waveguide portion 308 that carries a signal 301. Transmitters 310 and detectors 314 are operatively connected to the waveguide portion 308 and mounted to respective electronic components 312, 316. Those skilled in the art will appreciate that the cell phone 300 can be miniaturized as compared to conventional cell phones that utilize conventional wiring between components. Alternatively, the cell phone 300 can house more components than would be possible for a similarly sized cell phones of the prior art that utilizes conventional wiring between components. Additionally, the cell phone 300 is better able to withstand shock, for example from dropping the cell phone 300 on a hard surface. The increased shock resistance is due to the elimination of brittle wiring, including printed circuit boards and wiring harnesses and connecters.
Referring now to FIGS. 5 and 6, another embodiment of a device is shown, the device being in the form of a cellular telephone and referred to generally by reference numeral 400. Typically, electrical/electronic components of some devices, such as projectiles, are encased in a potting material, such as an epoxy, to harden the components against noise and shock due to the high acceleration and/or impact experienced by the projectile. In the embodiment of FIGS. 5 and 6, the potting material 402, which can be a solid, such as an epoxy, a gel, or a liquid is disposed within a casing 401 of the cellular telephone and is used as a communication bus between electrical/electronic components 404. The communication can be wholly within the potting material 402 or may be partially within the potting material 402 and partially in free space. Although many devices can be subjected to such noise and/or shock, a cellular telephone is described by way of example because of its tendency to be dropped or otherwise subjected to shock.
The communication through the potting material is carried out with a transmitter 406, which outputs any wavelength radiation that can propagate through the potting material 402 and detected by a receiver 408. It is preferred that the potting material 402 be a solid, such as an epoxy to provide hardening of the cellular telephone to shock and noise and it is further preferred that the radiation used as a communication medium is IR energy, preferably from a IR diode. In such an example, the epoxy need not be transparent or substantially transparent as long as it can carry an IR signal over a required distance, such as several hundred mm or less. An example of such an epoxy is Dolphon® CC-1024-A Low Viscosity Potting and Casting Epoxy Resin with RE-2000 Reactor mixed at a ratio of 10 parts resin to 1 part reactor, each of which is distributed by John C. Dolph Company. The same epoxy resin and reactor can be used for the waveguide portions 108, 208, or 308 discussed above with regard to FIGS. 1, 3, and 4.
IR technology is well known in the art, particularly in the art of remote control of electronic consumer goods. The IR data association (IrDA®) has standards for communicating data via short-range infrared transmission. Transmission rates fall within three broad categories SIR, MIR and FIR, SIR (Serial Infrared) speeds cover transmission speeds normally supported by an RS-232 port. MIR (Medium Infrared) usually refers to speeds of 0.576 Mb/s to 1.152 Mb/s. FIR (Fast Infrared) denotes transmission speeds of about 4 Mb/s. The standard has been modified for faster transmission speeds up to 16 Mb/s (referred to as very fast Infrared VFIR). Although not preferred, visible light, for example from a laser diode, may also be used to transmit communication signals through the potting material 402.
The transmitters 406 may be carried on printed circuit boards 410 which may also be encased in the potting material 402 or disposed freely throughout the potting material 402. The printed circuit boards each 410 preferably carry their own power supply, such as a battery 412 to eliminate internal wiring. Each of the electronic/electrical components 404 has a receiver 408 for communicating with the transmitters 406. As discussed above with regard to the first embodiment, each of the electrical/electronic components 404 preferably have a receiver 408 and a transmitter 406 such that they can carry out a two-way communication. An example of such a transceiver module 500 is shown in the schematic diagram of FIG. 6. FIG. 6 shows an (IrDA®) transceiver manufactured by Sharp Inc. (2P2W1001YP) which is relatively inexpensive and contains a high speed, high efficiency low power consumption light emitting diode (LD), a silicon PIN photodiode (PD) and a low power bipolar integrated circuit. The circuit contains an LED driver (TRX) and a receiver circuit (RCX) that delivers 4 Mb/s operation for distances of 1 meter. The LED emitter transmits at a nominal wavelength of 880nm with a radiant intensity in the range of 100 to 500 mW.sr−1, with a radiation angle of +/−15 degrees. The pin photodiode has an integrated amplifier (AMP) and comparator (CMP), which provide a fixed voltage output over a broad range of input optical power levels and data rates. The same or similar transceiver module 500 can also be used for the other embodiments described above with regard to FIGS. 1, 3, and 4.
The Infrared Data Association (IrDA) was formed in 1993. The Infrared Data Association specified wireless communication standard between portable devices, such as, computers, printers, digital cameras, etc., and is preferably used in the present communication links. The standard is widely used by the industry. For the physical layer, IrDA transreceivers broadcast infrared pulses in a cone that extends 15 degrees half angle to 30 degrees half angle. The typical range for IrDA communications is from 5 cm to 60 cm away from a transreceiver in the center of the cone. In practice, there are some devices on the market that do not reach one meter, while other devices may reach up to several meters. The IrDA standard also specifies IrLAP (Link Acsess Protocol) and IrLMP (Link Management Protocol).
For the particular case of establishing communications links in enclosed volumes such as within projectile body, due to the following reasons, the communication protocol scheme must tune the transmission rates so that the effects of multi-path effects do not interfere with the operation of the communications links.
It is noted that in the case of projectiles or other similar cases, the space within which the present optical communication bus is being established is enclosed, and in most cases with materials that are not transparent to the light spectrum being used. In addition, several electronics boards or devices or the like, some of which may have been potted in potting materials, may be located at different locations within the projectile body and communications links may have to be established between them. In addition, other electrical or mechanical components or energetic materials or the like which are generally non-transparent and may even have highly reflective surfaces are usually present in guided and smart munitions. For these reasons, when the transmitter element of an IR transreceivers transmits a pulse, the receiver element located on a separate IR transreceivers at a different location within the projectile body will receive the (“leading”) pulse signal, but may also receive several other (“following”) pulses (pulse-like signals) due to the multi-path effects, depending on their relative locations within the projectile body. The “following” pulses are generally weaker and die down quickly after several reflections due to absorption and dispersion. However, up to certain signal strength threshold, the “following” pulses may still register as transmitted signal.
For this reason, once a pulse is transmitted and the aforementioned “leading” pulse signal is received (by all present receivers), the next pulse can only be transmitted once the strength of the aforementioned “following” pulses have fallen below the aforementioned strength threshold. The time that it takes for the strength of the “following” pulses to fall below the aforementioned threshold determines the maximum transmission rate that can be used in the projectile. The said maximum transmission rate can be readily determined experimentally by transmitting a single pulse and waiting until no pulses above the aforementioned signal strength threshold is detected from any one of the present receivers. This process is preferably implemented on the processor being used to set up the communications bus insider the projectile to allow an appropriate transmission rate to be automatically selected.
It is appreciated by those skilled in the art that even though IrDA transreceivers are preferably used in the present munitions and the like applications for setting up a communications bus, however, if a particular application demands, optical transreceivers that operate at different light spectrum may also be employed.
The casing 402 can also be provided with a window portion 403, as shown in FIG. 5, which can be used to upload or input data or instructions into components of the cellular telephone through the potting material 402 (or through the waveguide portions 108, 208, and 308 discussed above). In a preferred implementation, the window portion 403 is in optical communication with the waveguide portion 108, 208, 308 or potting material 402 and transmits any input signals to the appropriate components on the interior of the cellular telephone. Although described in terms of a transparent window 403 and signal, the input signal can be any signal that propagates through the waveguide portion 108, 208, 308 or potting material 402, such as an IR or ultrasound signal. Furthermore, the window 403 does not have to be a transparent window but merely a portion of the casing, which is capable of transmitting a signal from the exterior of the cellular telephone to one or more components on the interior of the cellular telephone.
Referring now to FIG. 7, there is shown a cellular telephone according to another embodiment of the present invention, in which similar reference numerals from FIG. 5 denote similar features, the cellular telephone of FIG. 7 being referred to generally by reference numeral 600. FIG. 7 is similar to that of FIG. 5 with the exception that the potting material does not have to completely encase a portion of the cellular telephone's interior. The interior of the cellular telephone includes portions of free space 610 (which may be filled with air or other gases or may be evacuated. Although all of the components 404, 408 are shown encased in the potting material 402, they can also be provided in the free space 610 or partially in the free space 610. Thus, the communication between components is not only through the potting material 402 but can also be done through the free space 610 inside the cellular telephone.
While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims.

## Claims

1. A device other than a projectile, the device comprising:
a casing, at least a portion of which contains a potting material acting as the optical waveguide material;
a transmitter for transmitting a pulse based signal at least partially through the potting material; and
a receiver for receiving the pulse based signal after one or more reflections of the pulse based signal from interior surfaces of the casing;
the pulse based signal having a pulse rate configured such that a subsequent pulse doesn't interfere with reflections from an immediately previous pulse.

2. The device of claim 1, wherein the potting material is selected from a group consisting of a solid, a gel, and a liquid.

3. The device of claim 2, wherein the potting material is the solid and the solid is an epoxy resin.

4. The device of claim 1, wherein the signal is an infrared signal.

5. The device of claim 1, wherein the casing includes a window through which an input signal is transmitted from an exterior of the casing to at least one of the potting material and receiver.

6. A method for transmitting signals between components in a device other than a projectile, the method comprising:
filling at least a portion of the device with a potting material acting as an optical waveguide material;
transmitting a pulse based signal at least partially through the potting material acting as the optical waveguide material;
reflecting the pulse based signal from interior surfaces of the device; and
receiving the pulse based signal after one or more reflections;
wherein the pulse based signal has a pulse rate configured such that a subsequent pulse doesn't interfere with reflections from an immediately previous pulse.