Patent Grant
6888474
The present invention is generally related to light sources, and more particularly to traffic signal lights including those incorporating both incandescent and solid state light sources, and to configuring an electronically steerable beam of a traffic signal light.
Traffic signal lights have been around for years and are used to efficiently control traffic through intersections. While traffic signals have been around for years, improvements continue to be made in the areas of traffic signal light control algorithms, traffic volume detection, and emergency vehicle detection.
There continues to be a need to be able to predict when a traffic signal light source will fail. The safety issues of an unreliable traffic signal are obvious. The primary failure mechanism of an incandescent light source is an abrupt termination of the light output caused by filament breakage. The primary failure mechanism of a solid state light source is gradual decreasing of light output over time, and then ultimately, no light output.
The current state of the art for solid state light sources is as direct replacements for incandescent light sources. The life time of traditional solid state light sources is far longer than incandescent light sources, currently having a useful operational life of 10-100 times that of traditional incandescent light sources. This additional life time helps compensate for the additional cost associated with solid state light sources.
However, solid state light sources are still traditionally used in the same way as incandescent light sources, that is, continuing to operate the solid state light source until the light output is insufficient or non existent, and then replacing the light source. The light output is traditionally measured by a person with a light meter, measuring the light output from the solid state light source from a Department of Transportation (DOT) “bucket”.
Other problems with traditional traffic signal light sources is the intense heat generated by the light source. In particular, temperature greatly affects the life time of solid state light sources. If the temperature can be reduced, the operational life of the solid state light source may increase between 3 fold and 10 fold. Traditionally, solid state light sources today are designed as individual light emitting diodes (LEDs) individually mounted to a printed circuit board (PCB), and placed in a protective enclosure. This protective enclosure produces a large amount of heat and has severe heat dissipation problems, thereby reducing the life of the solid state light source dramatically.
In addition to temperature, oxidation also greatly effects the lifetime of solid state light sources. For instance, when oxygen is allowed to combine with aluminum on an aluminum gallium arsenide phosphorus (AlInGaP) LED, oxidation will occur and the light output is significantly reduced.
With specific regards to solid state light sources, typical solid state light sources comprised of LEDs are traditionally too bright early in their life, and yet not bright enough in their later stages of life. Traditional solid state light sources used in traffic control signals are traditionally over driven initially so that when the light reduces later, the light output is still at a proper level meeting DOT requirements. However, this overdrive significantly reduces the life of the LED device due to the increased, and unnecessary, drive power and associated heat of the device during the early term of use. Thus, not only is the cost for operating the signal increased, but more importantly, the overall life of the device is significantly reduced by overdriving the solid state light source during the initial term of operation.
Still another problem with traditional light sources for traffic signals is detection of the light output using the traditional hand held meter. Ambient light greatly affects the accurate detection of light output from the light source. Therefore, it has been difficult in the past to precisely set the light output to a level that meets DOT standards, but which light source is not over driven to the point of providing more light than necessary, which as previously mentioned, increases temperature and degrades the useful life of the solid state device.
Still another problem in prior art traffic signals is that signal visibility needs to be controlled so only specific lanes of traffic are able to see the traffic light. An example is when a left turn lane has a green light, and an adjacent lane is designated as a straight lane. It is necessary for traffic in the left turn lane to see the green light. The current visibility control mechanism is mechanical, typically implementing a set of baffles inserted into the light system to carefully point the light in the left lane in the correct direction. The mechanical direction system is not very controllable because it is controlled in only one dimension, typically either up or down, or, either right or left, but not both. Consequently, the light is undesirable often seen in the adjacent lane. There is arisen a need for a better method to control the visibility range of a traffic signal.
Traditionally, old technology is typically replaced with new technology by simply disposing of the old technology traffic devices. Since most cities don't have the budget to replace all traffic control devices when new ones come to market, they have traditionally taken the position of replacing only a portion of the cities devices at any given time, thereby increasing the inventory needed for the city. Larger cities end up inventorying between four and five different manufacture's traffic signals, some of which are not in production any longer. The added cost is not only for storage of inventoried items, but also the overhead of taking all different types of equipment to a repair site, or cataloging the different inventoried items at different locations.
With respect to alignment systems for traffic lights, traditionally alignment traffic control devices provide that one person points the generated light beam in the desired direction from a bucket while above the intersection, while another person stands in the traffic lanes to determine if the light is aligned properly. The person on the ground has to move over the entire field of view to check the light alignment. If the light is masked off (such as a turn arrow), there are more alignment iterations. There is desired a faster and more reliable method of aligning traffic signals.
Traffic lights also have a problem during darker conditions, i.e. at night or at dusk when the light is not well defined. This causes a problem if the light has to be masked off for any reason, whereby light may overlap to areas that should be off. This imprecise on/off boundary is called “ghosting”. There is a need to find an improved way to define the light/dark boundary of the traffic light to reduce ghosting. The ghosting is primarily caused by the angle the light hits on the “risers” on a Fresnel lens. A traffic light with a longer focal length reduces the angle, therefore decreasing the amount of ghosting. Therefore, devices with shorter focal lengths have increased ghosting. Another cause of ghosting is stray light from arrays of LED lights. Typical LED designs have a rather large intensity peek, that is, a less uniform beam of light being generated from the array.
Still another problem in prior art traffic signals is that signal visibility needs to be precisely controlled. An electronically steerable beam of a traffic signal light allows a viewing angle of a traffic signal light to be changed in order to enhance the safety of an intersection. Precisely controlling such a beam via a wireless device and altering the viewing angle of the traffic signal light eliminates possible ambiguity associated with an intersection having multiple traffic signal lights, light ball lenses and traffic signals. The wireless device allows the beam, and thus the viewing angle, to be altered from the vantage point of a vehicle at an intersection. From this point of view, a traffic engineer, for example, can interactively determine an optimal viewing angle of the signal. There is arisen a need for a better method to precisely control the visibility of a traffic signal.
The present invention achieves technical advantages as a system, method, and computer readable medium for configuring an electronically steerable beam of a traffic signal light to a desired viewing angle via a wireless device using an interactive methodology.
In one embodiment, a method for configuring an electronically steerable beam of a traffic signal light comprises receiving at least one command to change a viewing angle of a traffic signal light, translating the command to a power line command, sending the power line command to the traffic signal light, wherein the power line command effects an electronic steerable beam of the traffic signal light, and adjusting a viewing angle of at least a portion of the traffic signal light based on the power line command.
In another embodiment, a computer readable medium comprises instructions for receiving a command to change a viewing angle of at least one traffic signal light, wherein the traffic signal light comprises an array of columns and rows, performing at least one of a following action, based on the command, from a group consisting of: turning at least one of the columns on, turning at least one of the columns off, turning at least one of the rows on, and turning at least one of the rows off, and changing the viewing angle based on the performed action.
In a further embodiment, a method for configuring an electronically steerable beam of a traffic signal light comprises selecting a vantage point for beam steering, adjusting at least one of a following viewing perspective of the traffic signal light from a group consisting of: a horizontal viewing angle, a horizontal viewing width, a vertical viewing angle, and a vertical viewing width, and setting the adjusted at least one of the viewing perspectives.
In yet another embodiment, a system for configuring an electronically steerable beam of a traffic signal light comprises a wireless device adapted to send at least one command to change a viewing angle of a traffic signal light, a control unit adapted to receive the command, the control unit further adapted to: translate the command to a power line command, send the power line command to the traffic signal light, wherein the power line command effects an electronic steerable beam of the traffic signal light, and adjust a viewing angle of at least a portion of the traffic signal light based on the power line command.
In yet a further embodiment, a system for configuring an electronically steerable beam of a traffic signal light comprises a wireless device adapted to send at least one command to change a viewing angle of a traffic signal light, and a control unit adapted to receive the command, the control unit further adapted to send the command to the traffic signal light, wherein the command adjusts a viewing angle of at least a portion of the traffic signal light.
In still another embodiment, an electronic device comprises means for receiving at least one command to change a viewing angle of a traffic signal light, means for translating the command to a power line command, means for sending the power line command to the traffic signal light, wherein the power line command effects an electronically steerable beam of the traffic signal light, and means for adjust a viewing angle of at least a portion of the traffic signal light based on the power line command.
In still a further embodiment, a wireless device adapted to configure an electronically steerable beam of a traffic signal light to a desirable viewing angle and viewing width, wherein the traffic signal light comprises an array of columns and rows consisting of light emitting diodes, comprises means for performing at least one of a following action from a group consisting of: shift left, shift right, all columns on, all columns off, all rows on, all rows off, increase horizontal viewing angle, decrease horizontal viewing angle, shift up, shift down, increase vertical viewing angle, and decrease vertical viewing angle.
FIG. 1A and
FIG. 2A and
FIG. 18A and
Referring now to
Referring now to FIG. 1B and
Referring to
Still referring to
Referring now to
Solid state light assembly 40 is seen to comprise an array of light emitting diodes (LEDs) 42 aligned in a matrix, preferably comprising an 8×8 array of LEDs each capable of generating a light output of 1-3 lumens. However, limitation to the number of LEDs or the light output of each is not to be inferred. Each LED 42 is directly bonded to heatsink 20 within a respective light reflector comprising a recess defined therein. Each LED 42 is hermetically sealed by a glass material sealingly diffused at a low temperature over the LED die 42 and the wire bond thereto, such as 8000 Angstroms of, SiO2 or Si3N4 material diffused using a semiconductor process. The technical advantages of this glass to metal hermetic seal over plastic/epoxy seals is significantly a longer LED life due to protecting the LED die from oxygen, humidity and other contaminants. If desired, for more light output, multiple LED dies 42 can be disposed in one reflector recess. Each LED 42 is directly secured to, and in thermal contact arrangement with, heatsink 20, whereby each LED is able to thermally dissipate heat via the bottom surface of the LED. Interfaced between the planar rear surface of each LED 42 is a thin layer of heat conductive material 46, such as a thin layer of epoxy or other suitable heat conductive material insuring that the entire rear surface of each LED 42 is in good thermal contact with rear heatsink 20 to efficiently thermally dissipate the heat generated by the LEDs. Each LED connected electrically in parallel has its cathode electrically coupled to the heatsink 20, and its Anode coupled to drive circuitry disposed on daughterboard 60. Alternatively, if each LED is electrically connected in series, the heatsink 20 preferably is comprised of an electrically non-conductive material such as ceramic.
Further shown in
A daughter circuit board 60 is secured to one end of heatsink 20 and main circuit board 48 by a plurality of standoffs 62, as shown. At the other end thereof is a power supply 70 secured to the main circuit board 48 and adapted to provide the required drive current and drive voltage to the LEDs 42 comprising solid state light source 40, as well as electronic circuitry disposed on daughterboard 60, as will be discussed shortly in regards to the schematic diagram shown in FIG. 16. Light diffuser 50 uniformly diffuses light generated from LEDs 42 of solid state light source 40 to produce a homogeneous light beam directed toward window 16.
Window 16 is seen to comprise a lens 70, and a Fresnel lens 72 in direct contact with lens 70 and interposed between lens 70 and the interior of housing 12 and facing light diffuser 50 and solid state light source 40. Lid 14 is seen to have a collar defining a shoulder 76 securely engaging and holding both of the round lens 70 and 72, as shown, and transparent sheet 73 having defined thereon grid 74 as will be discussed further shortly. One of the lenses 70 or 72 are colored to produce a desired color used to control traffic including green, yellow, red, white and orange.
It has been found that with the external heatsink being exposed to the outside air the outside heatsink 20 cools the LED die temperature up to 50° C. over a device not having a external heatsink. This is especially advantageous when the sun setting to the west late in the afternoon such as at an elevation of 10° or less, when the solar radiation directed in to the lenses and LEDs significantly increasing the operating temperature of the LED die for westerly facing signals. The external heatsink 20 prevents extreme internal operating air and die temperatures and prevents thermal runaway of the electronics therein.
Referring now to
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Referring now back to FIG. 1A and
For instance, in one preferred embodiment the control electronics 60 has software generating and overlaying a grid along with the video image for display at a remote display terminal, such as a LCD or CRT display shown at 59 in FIG. 14A. This video image is transmitted electronically either by wire using a modem, or by wireless communication using a transmitter allowing the field technician on the ground to ascertain that portion of the road that is in the field of view of the generated light beam. By referencing this displayed image, the field technician can program which LEDs 42 should be electronically turned on, with the other LEDs 42 remaining off, such that the generated light beam will be focused by the associated optics including the Fresnel lens 72, to the proper lane of traffic. Thus, on the ground, the field technician can electronically direct the generated light beam from the LED arrays, by referencing the video image, to the proper location on the ground without mechanical adjustment at the light source, such as by an operator situated in a DOT bucket. For instance, if it is intended that the objects viewable and associated with the upper four windows defined by the grid should be illuminated, such as those objects viewable through the windows labeled as W in
Referring now to
Moreover, electronic circuitry 100 on daughterboard 60 can drive only selected LEDs 42 or selected 4×4 portions of array 40, such as a total of 16 LED's 42 being driven at any one time. Since different LED's have lenses 86 with different radius of curvature different thicknesses, or even comprised of different materials, the overall light beam can be electronically steered in about a 15° cone of light relative to a central axis defined by window 16 and normal to the array center axis.
For instance, driving the lower left 4×4 array of LEDs 42, with the other LEDs off, in combination with the diffuser 50 and lens 70 and 72, creates a light beam +7.5 degrees above a horizontal axis normal to the center of the 8×8 array of LEDs 42, and +7.5 degrees right of a vertical axis. Likewise, driving the upper right 4×4 array of LEDs 42 would create a light beam +10 degrees off the horizontal axis and +7.5 degrees to the right of a normalized vertical axis and −7.5 degrees below a vertical axis. The radius of curvature of the center lenses 86 may be, for instance, half that of the peripheral lenses 86. A beam steerable +/−7.5 degrees in 1-2 degree increments is selectable. This feature is particularly useful when masking the opening 16, such as to create a turn arrow. This further reduces ghosting or roll-off, which is stray light being directed in an unintended direction and viewable from an unintended traffic lane.
The electronically controlled LED array provides several technical advantages including no light is blocked, but rather is electronically steered to control a beam direction. Low power LEDs are used, whereby the small number of the LEDs “on” (i.e. 4 of 64) consume a total power about 1-2 watts, as opposed to an incandescent prior art bulb consuming 150 watts or a flood 15 watt LED which are masked or lowered. The present invention reduces power and heat generated thereby.
Referring now to
Referring now to
Shown generally at 102 is a clock circuit providing a clock signal on line 104 to pin 125 of the CPLD U1. Preferably, this clock signal is a square wave provided at a frequency of 32.768 KHz. Clock circuit 102 is seen to include a crystal oscillator 106 coupled to an operational amplifier U5 and includes associated trim components including capacitors and resistors, and is seen to be connected to a first power supply having a voltage of about 3.3 volts.
Still referring to
As shown at 112, an operational amplifier U6 is shown to have its non-inverting output connected to pin 109 of CPLD U1. Operational amplifier U9 provides a power down function.
Referring now to ambient light detection circuit 120, there is shown circuitry detecting ambient light intensity and comprising of at least one photodiode identified as PD1, although more than one spaced photodiode PD1 could be provided. An operational amplifier depicted as U10 is seen to have its non-inverting output coupled to input pin 100 of CPLD U1. The non-inverting input of amplifier U10 is connected to the anode of photodiode PD1, which photodiode has its cathode connected to the second power supply having a voltage of about 4.85 volts. The non-inverting input of amplifier U10 is also connected via a current via a current limiting resistor to ground. The inverting reference input of amplifier U10 is coupled to input 99 and 101 of CPLD U1 via a voltage divide network and comparators U8 and U9. A second comparator U11 has a non-inverting input also coupled to the anode of photodiode PD1, and the inverting reference input connected the resistive voltage divide network. Both comparators U10 and U11 determines if the DC voltage generated by the photodiode PD1, which is indicative of the sensed ambient light intensity, exceeds a respective different voltage threshold provided to the respective inverting input. A lower reference threshold voltage is provided to comparator U11 then the reference threshold voltage provided to comparator U10 to provide a second ambient light intensity threshold detection.
Referring now to the beam intensity detection circuit 122 including a comparator U7 and an optical feedback circuit 123, these components will now be discussed in detail. The beam intensity circuit 122 detects the intensity of backscattered light from Fresnel lens 72, as shown at 124 in
Referring to
Referring to
The inverting output of amplifier U20 is connected via a large series capacitor C30 to a node A. This node A is connected via a resistor R100 to a feedback node F as well as to the emitter of NPN transistor Q1. A larger capacitor C31 tied between the feedback node F and ground is substantially smaller than the capacitor C30, whereby resistor R100 and capacitor C31 provide an integrator function and operate as a low pass RC filter. The RC integrator comprised of R100 and capacitor C31 integrate the AC voltage at node A to provide a DC voltage at node F that is a function of both the duty cycle of the pulsed PWM AC voltage at node A as well as the amplitude of the pulsed PWM AC voltage at node A. Transistor Q1 in combination with resistor 200 and diode D3 maintain node A close to ground at one condition while allowing a variable high level signal.
By way of example, if the plurality of photodiode's PD2 sense incident pulsed light backscattered from Fresnel lens 72 at a first intensity and provide at summation node 125 a 1 millivolt peak-to-peak signal having a 50% duty cycle, amplifier U20 will provide a 0.5 volt peak-to-peak 50% duty cycle signal at its inverting output, which AC signal is integrated by resistor 100 and C31 to provide a 0.5 volt DC signal at feedback node F. For night operation, this 0.5 volt DC signal at feedback node F may correspond to the nominal intensity of the light beam generated by apparatus 10 and 40.
During day operation, it may be desired that the beam intensity generated by apparatus 10 and 40 produce backscattered light to photodiode's PD2 to be a 90% duty cycle signal introducing a 4 millivolt peak-to-peak AC voltage signal at summation node 125. Amplifier U20 will provide a gain of 1000 to this signal to provide a 4 volt peak to peak AC voltage at its inverting output which when integrated by the integrator R100 and capacitor C31 at a 90% duty cycle will yield a 3.6 volt DC signal at feedback node F.
Now, in the case when the intensity of the light output from apparatus 10 and 40 falls 10% from that minimum beam intensity required for night operation, a corresponding 0.9 millivolt peak-to-peak AC signal having a 50% duty cycle will be generated a summation node 125, thereby providing a 0.9 volt peak-to-peak AC signal at the output of amplifier U20, and a 0.45 volt DC signal at the feedback node F. This 0.45 volt DC signal provided at the feedback node F is provided back to the non-inverting input of comparator U7 in
In likewise operation, CPLD U1 will reduce the duty cycle or the drive current to the LED array slightly until the generated DC voltage signal at feedback node F is sensed by comparator U10 to fall below the reference voltage provided to the inverting input thereof. In this way, CPLD U1 responsively adjusts the duty cycle or drive current of the voltage signal driving the LED array such that the DC voltage provided at the feedback node F is slightly above the reference voltage provided to the inverting input of comparator U10.
Light apparatus 10 and 40 to present invention is adapted to provide different beam intensities depending on the ambient light that the traffic signal is operating in, which ambient light intensity is determined by photodiode's PD1 and circuit 120 as previously described. If CPLD U1 determines via circuit 120 day operation with high intensity ambient light beam sensed by photodiode PD1, the reference voltage provided to the inverting input of comparator U10 is increased to a second pre-determined threshold. CPLD U1 will provide a drive signal to transistor Q35 and LED drive circuit 130 with a sufficient duty cycle and drive current, increasing the beam intensity of the apparatus 10 and 40 until the feedback circuit 123 generates a DC voltage at feedback node F as sensed by comparator U10 corresponding to a reference voltage at the inverting input thereof.
Likewise, when the ambient detection photodiode PD1 and circuit 120 determines night operation, or maybe operation during a storm creating darker ambient light conditions, CPLD U1 will provide a second predetermined DC voltage reference to the inverting input of comparator U10. CPLD U1 reduces the duty cycle or drive current of the drive signal to LED circuit 130 until optical feedback circuit 123 is determined by comparator U10 to generate a DC voltage at node F corresponding to this reduced voltage reference signal corresponding to a darkened operation.
The optical feedback circuit 123 derives advantages in that backscattered light is sensed indicative of the pulsed generated light from the apparatus 10 and 40 to directly provide an indication of a generated light intensity therefrom. A plurality of photodiode's PD2 are provided in parallel having their outputs summed at summation node 125, whereby degradation or failure of one photodiode PD2 does not significantly effect the accuracy of the detection circuit. The optical feedback circuit 123 provides a DC voltage at feedback node F that directly corresponds to the sensed pulsed light, and which is not effected by the ambient light since the DC component generated by the photodiode's PD2 due to ambient light is filtered out. In this way, the optical feedback circuit 123 comprising detection circuit 122 accurately senses intensity of the pulsed light beam from the apparatus 10 and 40. CPLD U1 always insures an adequate and appropriate beam intensity is generated by apparatus 10 and 40 without overdriving the LED array, and while always meeting DOT requirements.
An LED drive circuit is shown at 130 serially interfaces LED drive signal data to drive circuitry of the LEDs 42 as shown in FIG. 16C.
Shown at 140 is another connector adapted to interface control signals from CPLD U1 to an initiation control circuit for the LED's 42.
Each of the LEDs 42 is individually controlled by CPLD U1 whereby the intensity of each LED 42 is controlled by the CPLD U1 selectively controlling a drive current thereto, a drive voltage, or adjusting a duty cycle of a pulse width modulation (PWM) drive signal, and as a function of sensed optical feedback signals derived from the photodiodes as will now be described in reference to FIG. 17.
Referring to
CPLD U1 individually controls the drive current, drive voltage, and PWM duty cycle to each of the respective LEDs 42 as a function of the light detected by circuits 120 and 122 as shown in FIG. 16D. For instance, it is expected that between 3 and 4% of the light generated by LED array 40 will back-scatter back from the Fresnel lens 72 toward to the circuitry 100 disposed on daughterboard 60 for detection. By normalizing the expected reflected light to be detected by photodiodes PD2 in circuit 122, for a given intensity of light to be emitted by LED array 40 through window 16 of lid 14, optical feedback is used to ensure an appropriate light output, and a constant light output from apparatus 10.
For instance, if the sensed back-scattered light, depicted as rays 124 in
Preferably, each of the LEDs is driven by a pulse width modulated (PWM) drive signal, providing current during a predetermined portion of the duty cycle, such as for instance, 50%. As the LEDs age and decrease in light output intensity, and also during day operation due to daily temperature variations, the duty cycle and/or drive current may be responsively, slowly and continuously increased or adjusted such that the duty cycle and/or drive current until the intensity of detected light using photodiodes PD2 is detected by comparator U10 to be the normalized detected light for the operation, i.e. day or night, as a function of the ambient light. When the light sensed by photodides PD2 are determined by controller 60 to fall below a predetermined threshold indicative of the overall light output being below DOT standards, a notification signal is generated by the CPLD U1 which may be electronically generated and transmitted by an RF modem, for instance, to a remote operator allowing the dispatch of service personnel to service the light. Alternatively, the apparatus 10 can responsively be shut down entirely.
Referring now to FIG. 18A and
The solid state light apparatus 10 of the present invention has numerous technical advantages, including the ability to sink heat generated from the LED array to thereby reduce the operating temperature of the LEDs and increase the useful life thereof. Moreover, the control circuitry driving the LEDs includes optical feedback for detecting a portion of the back-scattered light from the LED array, as well as the intensity of the ambient light, facilitating controlling the individual drive currents, drive voltages, or increasing the duty cycles of the drive voltage, such that the overall light intensity emitted by the LED array 40 is constant, and meets DOT requirements. The apparatus is modular in that individual sections can be replaced at a modular level as upgrades become available, and to facilitate easy repair. With regards to circuitry 100, CPLD U1 is securable within a respective socket, and can be replaced or reprogrammed as improvements to the logic become available. Other advantages include programming CPLD U1 such that each of the LEDs 42 comprising array 40 can have different drive currents or drive voltages to provide an overall beam of light having beam characteristics with predetermined and preferably parameters. For instance, the beam can be selectively directed into two directions by driving only portions of the LED array in combination with lens 70 and 72. One portion of the beam may be selected to be more intense than other portions of the beam, and selectively directed off axis from a central axis of the LED array 40 using the optics and the electronic beam steering driving arrangement.
Referring now to
Referring now to
A communication link 238 allows information to be sent from the device 102 to the control unit housed in the cabinet 236. The communication link 238 may be a wireless link, a wired link, and/or a combination of a wireless and wired link. A power line 240 allows information to be sent from the control unit housed in the cabinet 236 to the LED array housed in the traffic signal light 234. In an alternate embodiment, communication from the control unit to the traffic signal light 234 may occur via a wireless communication link, a wired communication link, and/or a combination of a wireless and a wired communication link. In another alternate embodiment, other information from the wireless device 232 can be sent to the control unit, and other information from other components in the cabinet 236 can be sent to the traffic signal light 234.
In yet another alternate embodiment, information can be exchanged between the control unit housed in the cabinet 236 and the wireless device 232, between the control unit and the traffic light signal 234, between the control unit and the LED array, between the LED array and the wireless device, and/or between the traffic light signal and the wireless device. For example, the traffic light signal 234 and/or the control unit could send the wireless device 232 updates, status messages, alarms, or various other information relating to the control unit, the cabinet 236, the traffic signal light 234, the communication link 238, and/or the power line 240. Such various other information may include suggestions to further configure the electronically steerable beam to a different viewing angle based on a current traffic situation, a potential traffic situation, a weather situation, and/or any activity that could impact a viewing angle of all of or a portion of the traffic signal light 234.
Referring now to
In an alternate embodiment, the control unit may be contained in another device such as another wireless device, a computer, and/or any device able to communicate with an LED array of a traffic signal light and/or with any other element of a traffic signal light.
Referring now to
Further described, an embodiment of the present invention allows an electronically steerable beam of a traffic signal light to be configured to a desired viewing angle remotely using an interactive methodology. At least one command to change the viewing angle of a specific traffic light are entered using a wireless device. The command is then sent over a communication link to a control unit within a cabinet. After receiving the command, the control unit translates the command to a power line command and sends it over that interface. The power line to the traffic light signal can be used as a low cost communication channel by modulating the signal and adding it to a power line voltage. The addressed light adjusts its viewing angle and stores this state in its flash memory. This command response cycle can be completed in milliseconds, which will allow the operator to interactively adjust the viewing angle optimally within a very short time.
Configuration of the electronically steerable beam traffic signal light is usually performed once after installation of the traffic signal light. The state of the light is retained in its flash memory, and whenever the light is powered on, it will start with the desired viewing angle. Security in the communication channel is achieved by using encrypted secure protocols.
Precisely controlling the viewing angle of the traffic signal light eliminates possible ambiguity associated with an intersection having multiple light ball lenses and multiple traffic signals. The wireless device or remote control unit allows the electronically steerable beam to be controlled from the vantage point of a vehicle at an intersection. From this point of view, a traffic engineer, for example, can interactively determine an optimal viewing angle. An example of the wireless device 232, 262, is depicted in FIG. 27.
Referring now to
In an alternate embodiment, a resulting pictorial view associated with the element selection can be displayed via the wireless device 232, 262. Further, a desired view, based on a location of a traffic engineer, can be sent to the control unit which can convert such a location to an associated viewing angle and provide such a viewing angle.
Referring now to
An advanced traffic light command protocol for controlling an electronically steerable beam preferably contains the following format: ESB column_bits row_bits where column_bits is an integer whose binary representation encodes the column on/off states and row_bits is an integer whose binary representation encodes the row on/off states. For example, the 10 by 6 array 280 would use column_bits values between 0 and 1023 to allow control of all 10 columns of the array.
Described further, the protocol includes the following commands that are preferably implemented by the control unit 252. Each of the commands appears in the left box and its response appears in the right box. The command protocol can be encapsulated into a power line modem protocol, for example, which may further be encapsulated within TCP/IP, for example. The serial interface is preferably 4800 bps uplink and 9600 bps downlink, 8 data bits, 1 stop bit and no parity. Other commands may be added and the present commands may be altered or deleted, and other serial interfaces may be used and the preferred interface may be altered.
The software running on the wireless device 232, 262 is adapted to translate the actions of the user and the screen to a command in the above format. Speech recognition may be used to control the electronically steerable beam by voice. Phrases spoken by the user are translated into electronically steerable beam column commands and/or row commands. The following table is a list of voice commands, but does not preclude other voice commands:
Referring now to
The vertical viewing angle is then adjusted and set at step 300. The width of the vertical viewing angle is then adjusted at step 302. At step 304, a determination is made regarding the width of the vertical viewing angle. If the width is too narrow or wide, or otherwise not proper, the width is again adjusted at step 302 until it is correct. Finally the overall angles are checked at step 306 and if correct the process is complete. If they are not satisfactory, then the horizontal viewing angle is again adjusted and set at step 294 and the process continues as described above.
While the invention has been described in conjunction with preferred embodiments, it should be understood that modifications will become apparent to those of ordinary skill in the art and that such modifications are therein to be included within the scope of the invention and the following claims.
The present application is a Continuation-In-Part of U.S. patent application Ser. No. 09/649,661 filed Aug. 29, 2000, now U.S. Pat. No. 6,614,358 entitled SOLID STATE LIGHT WITH CONTROLLED LIGHT OUTPUT, the teachings of which are incorporated by reference herein.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5132682 | Higgins et al. | Jul 1992 | A |
| 5309155 | Hsien et al. | May 1994 | A |
| 6323781 | Hutchison | Nov 2001 | B1 |
| 6441750 | Hutchison | Aug 2002 | B1 |
| 6450662 | Hutchison | Sep 2002 | B1 |
| 6577247 | Giacaman | Jun 2003 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20040070520 A1 | Apr 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 09649661 | Aug 2000 | US |
| Child | 10643135 | US |
