GB2307577A - Communication system - Google Patents

Communication system Download PDF

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Publication number
GB2307577A
GB2307577A GB9622650A GB9622650A GB2307577A GB 2307577 A GB2307577 A GB 2307577A GB 9622650 A GB9622650 A GB 9622650A GB 9622650 A GB9622650 A GB 9622650A GB 2307577 A GB2307577 A GB 2307577A
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United Kingdom
Prior art keywords
signal
relay
system
user
means
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB9622650A
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GB9622650D0 (en
Inventor
Anthony Michael David Marvin
Original Assignee
Anthony Michael David Marvin
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Filing date
Publication date
Priority to GB9522238A priority Critical patent/GB9522238D0/en
Application filed by Anthony Michael David Marvin filed Critical Anthony Michael David Marvin
Publication of GB9622650D0 publication Critical patent/GB9622650D0/en
Publication of GB2307577A publication Critical patent/GB2307577A/en
Application status is Withdrawn legal-status Critical

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B10/00Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • GPHYSICS
    • G08SIGNALLING
    • G08BSIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B1/00Systems for signalling characterised solely by the form of transmission of the signal

Abstract

An underground communication system for providing communication between miners (58, 60, 62, 64) situated in stopes (50, 52, 54, 56) radiating from a mine adit (48), and a remote location (65). Each miner is provided with a light source, such as a miner's lamp, with which an optical user signal (72, 74, 76,78) with a predetermined characteristic or modulation is generatable. Relay stations (66, 68, 70) situated in the adit (48) outside the stopes (50, 52, 54, 56) receive a user signal from one of the light sources and transmit a relay signal (80, 82, 83) directly or indirectly to the remote location (65). Each relay station (66, 68, 70) preferably adds its own unique identification code to the relay signal (80, 82, 83) and includes means to suppress retransmission of a relay signal including that code and also includes means to transmit a confirmation signal to the miner upon receipt of either a user signal with the required characteristic or a return signal generated at the remote location.

Description

COMMUNICATION SYSTEM The present invention relates to an underground communication system and to a method of communicating underground.

In an ore mine it is customary for substantially horizontal adits to radiate from a vertical shaft and for stopes, each of which follows a lode or vein of ore to radiate from the adits. A miner working in a stope normally throws mined ore into the adit as it is excavated and periodically leaves the stope and enters the adit where a communication system is installed which enables the miner to signal to a scraper winch operator that there is a requirement for a scraper to drag the pile of ore along the adit to an obliquely sloping ore pass down which ore falls to a collection point. Periodically, a receptacle positioned at the collection point will be hauled to the surface, emptied and returned to the collection point. The communication system normally comprises a hand pullable wire which runs from adjacent the stope to a remote location at which a scraper winch is situated.When the wire is pulled, tensioning causes actuation of a whistle or claxon next to a winch operator in order to alert the operator to the fact that the winch should be operated.

There are a number of disadvantages to using such a communication system. Firstly, it is necessary for the miner to leave the stope each time there is a requirement to actuate the scraper winch. Secondly, the effectiveness of the communication system is reliant on the length of the wire, straightness, friction etc. .... . Thirdly, the installation or moving of such a communication system is a time consuming and expensive operation.

An object of the invention is to provide an underground communication system which overcomes at least one of the above disadvantages.

Thus according to the invention there is provided a system for providing communication underground between a user and a remote location comprising a light source actuable by the user to produce an optical user signal and relay means adapted to be situated remotely from the user and including at least a first relay station having means to receive the user signal and means for transmitting a relay signal directly or indirectly to the remote location upon receipt of the user signal.

Such a system will enable the miner, without leaving the stope, and with a cap lamp with which miners are invariably provided, to alert an operator of an item of equipment, such as a scraper winch, which is situated at the remote location, to the fact that actuation of the equipment is necessary. Alternatively, the relay signal can be used to directly actuate the item of equipment.

When the distance over which the relay signal needs to be transmitted is large, the relay signal may advantageously be a radio signal.

In addition to the user signal, the relay signal may also be a light signal. When the background level of light used for illumination purposes is high, the use of a miner's lamp to actuate the system may not be possible due to the relatively low power of miners' lamps. In such situations, the use of an infrared light user signal will be preferred. Also because of background light considerations, the relay signal may also be an infrared light signal.

The user relay signal may alternatively comprise a sound signal which may be within the audible frequency range.

In order that an operator at the remote location will not need to directly detect a signal transmitted from the relay station, the system preferably includes apparatus located at the remote location including receiver means and a signalling device adapted to provide a visual or audible signal for alerting the operator upon receipt of the relay signal. Instead of the signalling device, the apparatus may include equipment actuation means for automatically causing actuation of an item of equipment, for example a scraper winch, upon receipt of the relay signal.

So as to avoid accidental or unintentional actuation of the equipment, the relay station is preferably adapted to only produce the relay signal upon receipt of a user signal having a particular characteristic or modulation. Particularly when the user signal is provided by a miner's lamp, the required modulation preferably comprises a signal of a predetermined duration or one or more interruptions of the user signal. A simple modulation pattern which is easily detectable and analysable by the relay station is one which results in the user signal comprising a plurality of sequential signals each of a duration within a first duration range separated by periods each having a duration within a second duration range.

Such modulation can easily be provided by the miner switching his lamp on and off or moving the beam from side to side and scanning it over the relay station.

So that the relay signal can be easily transmitted over a convoluted path and around obstructions or over longer distances the relay means preferably comprises one or more subsidiary relay stations each of which includes relay signal receiving means for receiving the relay signal from the first or another subsidiary relay station and transmitting means for transmitting the relay signal.

In order to avoid the relay signals received and transmitted by a particular subsidiary relay station from cancelling or otherwise interfering with each other, preferably in each subsidiary relay station the frequency of the relay signal transmitted by its transmitting means differs from the frequency of the relay signal that the subsidiary relay station is adapted to receive with its relay signal receiving means. Such problems can be even more effectively overcome if, in each subsidiary relay station, the relay signal transmitted by its transmitting means is a radio frequency spread spectrum transmission relay signal and its relay signal receiving means is adapted to receive a radio frequency spread spectrum transmission relay signal.

Preferably each subsidiary relay station includes means to receive an optical user signal and means responsive to the receipt of such a signal to transmit a relay signal directly or indirectly to the remote location.

With such an arrangement it will be possible, by arranging relay stations outside a plurality of stopes, for one such system to provide communication between a number of miners located in different stopes with the same remote location.

In order to facilitate handling of signals being transmitted by the system, preferably each relay station has its own unique identification code and coding means for adding this code to any relay signal transmitted thereby.

When such coding means are provided, preferably the or each relay station includes suppressing means which prevents retransmission of a relay signal including its own unique identification code.

Preferably the or each relay station has visual or audible signalling means which is capable of emitting a confirmation signal which is emitted upon receipt by the relay station in question of a user signal having the required characteristic or modulation. The user issuing the user signal will thereby receive confirmation of successful receipt by the relay station of the user signal.

More preferably the system includes return signalling means which is adapted to send a return signal back to the relay station which received the user signal upon successful receipt of the relay signal at the remote location and wherein the confirmation signal is emitted upon receipt by the relay station of sudh a return signal.

In order to facilitate identification of the relay station from which the confirmation signal is to be emitted, preferably the return signalling means is adapted to include coded information in the return signal identifying the relay station which received the user signal.

So as to avoid the requirement to station an operator at the remote location, in order to actuate an item of equipment situated at or near to the remote location, preferably the system includes, at the remote location, equipment activating means and relay signal receiving means arranged to actuate an item of equipment with the activating means upon receipt of the relay signal.

As the system is designed to be situated in an aggressive environment, preferably the or each relay station comprises a sealed unit substantially impervious to dust and dampness.

According to a second aspect of the invention there is provided a method of communicating underground between a user and a remote location comprising the steps of: (a) the user actuating a radiative light source to produce an optical user signal; (b) receiving the user signal with a relay means including at least one relay station situated remotely from the user; (c) the relay station generating a relay signal upon receipt of the user signal; (d) transmitting the relay signal directly or indirectly to the remote location; and (e) receiving the relay signal at the remote location.

The invention will now be described by way of example only with reference to the accompanying drawings in which: FIG. 1 shows a schematic representation of a communication system according to a first embodiment of the invention; FIG. 2 shows a graph representing modulation of the user signal; FIG. 3 shows a schematic plan view of a mine including a communication system according to a second embodiment of the invention; FIG. 4 is a schematic vertical cross-section on the line 4-4 through the mine shown in Fig. 3; FIG. 5 shows a schematic plan view of a mine including a communication system according to a third aspect of the invention; and FIG. 6 shows a schematic view of a relay station.

The mine shown in Fig. 3 includes a vertical shaft 2 from which an adit 4 with radiating stopes 6 extends. A scraper winch 8 is located in the adit and is connected by a cable 10 to a scraper 12. The cable 10 passes round a pulley 14 located on the side of the scraper remote from the winch in order that rotation of the winch in a first direction causes the cable to be wound onto a first drum 16 and draw the scraper towards the winch and rotation of the winch in the opposite direction causes cable to be paid off the first drum 16 and wound on to a second drum 18 thus causing the scraper 12 to be drawn towards the pulley 14.

A downwardly sloping ore pass 20 extends from the floor of the adit 4 to a collection point 22 at the bottom of the shaft 2.

In Fig. 3 a miner 24, who is located in one of the stopes, is excavating ore which is then thrown into the adit 4 where it forms an ore pile 26.

A relay station 30, which is viewable by the miner 24 in the stope 6, is mounted in the adit and a receiver 32 is situated adjacent the winch 8. A visual or audible alarm such as a claxon 34 is connected to the receiver 32 for actuation thereby.

Periodically, the miner 24 will flash his lamp 28 at the relay station 30 in the manner shown in Fig. 2. The user signal 36 produced by the lamp comprises three flashes each of a minimum duration Etl with consecutive flashes separated by a gap of minimum duration 6t2. As discussed above, the signal 36 may alternatively be provided by an infrared emitter rather than a helmet lamp and the modulation may differ from that described above. So that the effects of dust and damp on the relay station can be minimised it preferably comprises a sealed unit into which the user signal passes through a window. Power for operating the relay station is provided by a rechargeable battery pack similar to that used to power miners' lamps and which is connectable to the relay station by some quick connect arrangement such as a jack plug connection.Once the relay station has analysed the modulation of the user signal 36 and ascertained that it fulfils the required criteria, the relay station generates a relay signal 38 which is transmitted to the receiver 32 situated adjacent the winch 8. The relay signal may a visible light, infrared light, radio, sound or any other suitable signal.

This relay signal causes the receiver to actuate the claxon 34 in order to alert a winch operator 40 to the fact that the winch 8 should be operated. The winch operator then starts the winch 8 causing one run of the cable 10 to be wound onto the first drum 16, thus causing the scraper 12 to be drawn along the adit 4 until the ore pile 26 falls down the ore pass 20 to a basket 42 situated at the collection point 22 at the bottom of the shaft 2. The winch operator then reverses the direction of rotation of the winch thus causing cable to unwind from the first drum 16 and be wound onto the second drum 18. This causes the scraper 12 to return to the position shown in Fig. 3.

For the reasons discussed above the receiver is preferably a sealed unit similar to the relay station which is powered by a rechargeable battery.

Instead of alerting a winch operator 40 to the requirement for winch actuation, the receiver 32 may be arranged to automatically actuate the winch. With such an arrangement, means will be provided for automatically stopping the winch and reversing its direction of rotation in order that the scraper will be returned to the position shown in Fig. 3.

Fig. 1 shows an alternative communication system also in accordance with the present invention in which a relay station 44 is arranged to actuate a claxon 46 directly, upon receipt of a user signal 36 modulated in the correct manner. Such a system will only be suitable when the relay station 44 is situated sufficiently close to the winch operator for him to clearly hear the claxon 46. The relay station 44 may alternatively actuate a visible rather than an audible alarm.

Fig. 5 shows a schematic plan view of a further mine in which a communication system according to a third aspect of the invention has been installed.

The mine includes an adit 48 with three sections from which four stopes 50, 52, 54 and 56 extend in which four miners 58, 60, 62 and 64 are respectively working.

Each miner has a helmet lamp with which he can produce a user signal 72, 74, 76 and 78 having the required modulation.

In the adit 48 a first relay station 66 is provided which is viewable by the miners 62 and 64 and two further subsidiary relay stations 68 and 70 are provided which are respectively viewable by the miners 60 and 58 and will be referred to as second and third relay stations.

A remote location 65, which in this example does not include any item of equipment such as a scraper winch, is shown at one end of the adit 48.

When the miner 64 wishes to communicate with the remote location 65 he flashes his helmet lamp to produce a user signal 72 having the required modulation which is analysed by a user signal receiver 90 (see Figure 6) in the first relay station 66. Provided the user signal 72 has the required modulation, a signalling means 92 in the first relay station emits an audible or visual confirmation signal 84 which indicates to the miner 64 that the first relay station 66 has received the user signal 72. A relay signal transmitter 94 in the first relay station 66 will then transmit the first part 80 of the relay signal at a first radio frequency F1 together with a code C1 generated by a coding means 96 in the first relay station 66.The first part 80 of the relay signal is received by a relay signal receiver 98 in the second relay station 68 which in turn transmits a second part 82 of the relay signal at a second radio frequency F2 and with the code C1 and a further code C2 generated by coding means in the second relay station 68.

Should any part of the relay signal be reflected back towards or reach the receiver of a relay station (e.g.

second relay station 68) through which the relay signal has already passed, then suppressing means 100 in a processing unit 102 of that relay station will detect the code (e.g.

code C2) added to the relay signal by that relay station and prevent onward retransmission of the relay signal.

Each relay station includes such suppressing means 100.

The second part 82 of the relay signal is then respectively received and transmitted at a third radio frequency F3 and with a further identifying code C3 by receiver and transmitter means of the third relay station 70 to produce a third part 83 of the relay signal.

Finally, the third part 83 of the relay signal is received by a receiver situated at the remote location 65.

Instead of the signalling means 92 of the first relay station 66 emitting a confirmation signal 84 as a direct consequence of receipt of the user signal 72 it may do so as a consequence of receiving a return signal 88 produced by return signalling means 86 provided at the remote location. This return signal 88 is transmitted through the third 70 and second 68 relay stations to the first relay station 66 where coding in the return signal 88 is recognised, resulting in the confirmation signal 84 being transmitted. In this way the miner 64 receives confirmation that the communication with the remote location 65 has been successfully achieved.

Each of the subsidiary relay stations 68 and 70 includes a user signal receiver 90 capable of detecting an optical user signal having the required modulation and will generate a relay signal upon receipt of such a user signal.

The relay stations also include signalling means 92 for producing a confirmation signal 84 as discussed above.

The use of a communication system according to the invention accordingly provides a facility whereby a miner in an inaccessible location can easily alert an operator at a remote location to a requirement to actuate an item of machinery. Alternatively, the miner can actuate the item of machinery remotely without an operator being necessary.

This in turn will lead to greater efficiency in the mining operation. Furthermore, the communication system can be constructed to be resistant to conditions likely to be encountered in a mine environment and be actuable by equipment invariably carried by miners thus obviating the necessity for a miner using the system to carry additional equipment.

Claims (33)

CLAIMS:
1. A system for providing communication underground between a user and a remote location comprising a light source actuable by the user to produce an optical user signal and a relay means adapted to be situated remotely from the user and including at least a first relay station having means to receive the user signal and means for transmitting a relay signal directly or indirectly to the remote location upon receipt of the user signal.
2. The system of claim 1 wherein the relay means includes only the first relay station which is adapted to transmit the relay signal directly to the remote location.
3. The system of claim 1 wherein the relay means also comprises one or more subsidiary relay stations.
4. The system of claim 3 wherein the or each subsidiary relay station includes relay signal receiving means for receiving the relay signal from the first or another subsidiary relay station and transmitting means for transmitting the relay signal.
5. The system of any one of claims 1 to 4 wherein the relay signal comprises a radio signal.
6. The system of claims 4 and 5 wherein in each subsidiary relay station the frequency of the relay signal transmitted by its transmitting means differs from the frequency of the relay signal that the subsidiary relay station is adapted to receive with its relay signal receiving means.
7. The system of claim 4 and claim 5 or claim 6 wherein in each subsidiary relay station the relay signal transmitted by its transmitting means is a spread spectrum transmission relay signal and its relay signal receiving means is adapted to receive a spread spectrum transmission relay signal.
8. The system of any one of claims 1 to 4 wherein the relay signal comprises an optical signal.
9. The system of claim 8 wherein the relay signal comprises an infrared light signal.
10. The system of any one of claims 1 to 4 wherein the relay signal comprises a sound signal.
11. The system of claim 10 wherein the relay signal comprises a sound signal in the audible frequency range.
12. The system of any preceding claim wherein the user signal comprises an infrared light signal.
13. The system of claim 3 or any claim dependent thereon wherein each subsidiary relay station includes means to receive an optical user signal and means responsive to the receipt of such a signal to transmit a relay signal directly or indirectly to the remote location.
14. The system of any preceding claim wherein the or each relay station has its own unique identification code and coding means for adding this code to any relay signal transmitted thereby.
15. The system of claim 14 wherein the or each relay station includes suppressing means which prevents retransmission of a relay signal including its own unique identification code.
16. The system of any preceding claim wherein the or each relay station is adapted to only transmit the relay signal upon receipt of a user signal having a particular characteristic or modulation.
17. The system of claim 16 wherein the required characteristic comprises a signal of a predetermined duration.
18. The system of claim 16 or 17 wherein the required modulation comprises interruption of the user signal.
19. The system of claim 16, 17 or 18 wherein the required modulation results in a plurality of sequential signals each of a predetermined minimum duration.
20. The system of claim 16, 17, 18 or 19 wherein the required modulation results in a plurality of sequential signals separated by periods not longer than a predetermined maximum duration.
21. The system of any one of claims 16 to 20 wherein the or each relay station has visual or audible signalling means which is capable of emitting a confirmation signal.
22. The system of claim 21 wherein the confirmation signal is emitted upon receipt by the relay station in question of a user signal having the required characteristic or modulation.
23. The system of claim 21 or 22 further including return signalling means which is adapted to send a return signal back to the relay station which received the user signal upon successful receipt of the relay signal at the remote location and wherein the confirmation signal is emitted upon receipt by the relay station of such a return signal.
24. The system of claim 23 wherein the return signalling means is adapted to include coded information in the return signal identifying the relay station which received the user signal.
25. The system of any preceding claim including, at the remote location, equipment activating means and relay signal receiving means arranged to actuate an item of equipment with the activating means upon receipt of the relay signal.
26. The system of claim 25 wherein the equipment is a scraper winch.
27. The system of any preceding claim wherein the or each relay station comprises a sealed unit substantially impervious to dust and dampness.
28. A method of communicating underground between a user and a remote location comprising the steps of: (a) the user actuating a light source to produce an optical user signal; (b) receiving the user signal with relay means including at least one relay station situated remotely from the user; (c) the relay station generating a relay signal upon receipt of the user signal; (d) transmitting the relay signal directly or indirectly to the remote location; and (e) receiving the relay signal at the remote location.
29. The method of claim 28 including the additional step of directly or indirectly controlling equipment or machinery situated at or near the remote location by the relay signal.
30. A system for providing communication underground between a user and a remote location substantially as hereinbefore described with reference to the accompanying drawings.
31. A method of signalling to an operator of equipment underground substantially as hereinbefore described with reference to the accompanying drawings.
32. A method of controlling equipment underground substantially as hereinbefore described with reference to the accompanying drawings.
33. A method of communicating underground between a user and a remote location substantially as hereinbefore described with reference to the accompanying drawings.
GB9622650A 1995-10-31 1996-10-31 Communication system Withdrawn GB2307577A (en)

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GB2307577A true GB2307577A (en) 1997-05-28

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Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2318939A (en) * 1996-11-01 1998-05-06 Richard James Harvey Infra-red identification device
US8521035B2 (en) 2008-09-05 2013-08-27 Ketra, Inc. Systems and methods for visible light communication
WO2013126585A1 (en) * 2012-02-21 2013-08-29 Ketra, Inc. System and method of extending the communication range in a visible light communication system
US8674913B2 (en) 2008-09-05 2014-03-18 Ketra, Inc. LED transceiver front end circuitry and related methods
US8749172B2 (en) 2011-07-08 2014-06-10 Ketra, Inc. Luminance control for illumination devices
US8773336B2 (en) 2008-09-05 2014-07-08 Ketra, Inc. Illumination devices and related systems and methods
US8886047B2 (en) 2008-09-05 2014-11-11 Ketra, Inc. Optical communication device, method and system
US9146028B2 (en) 2013-12-05 2015-09-29 Ketra, Inc. Linear LED illumination device with improved rotational hinge
US9155155B1 (en) 2013-08-20 2015-10-06 Ketra, Inc. Overlapping measurement sequences for interference-resistant compensation in light emitting diode devices
US9237620B1 (en) 2013-08-20 2016-01-12 Ketra, Inc. Illumination device and temperature compensation method
US9237612B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a target lumens that can be safely produced by an illumination device at a present temperature
US9237623B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a maximum lumens that can be safely produced by the illumination device to achieve a target chromaticity
US9247605B1 (en) 2013-08-20 2016-01-26 Ketra, Inc. Interference-resistant compensation for illumination devices
US9276766B2 (en) 2008-09-05 2016-03-01 Ketra, Inc. Display calibration systems and related methods
US9332598B1 (en) 2013-08-20 2016-05-03 Ketra, Inc. Interference-resistant compensation for illumination devices having multiple emitter modules
US9345097B1 (en) 2013-08-20 2016-05-17 Ketra, Inc. Interference-resistant compensation for illumination devices using multiple series of measurement intervals
US9360174B2 (en) 2013-12-05 2016-06-07 Ketra, Inc. Linear LED illumination device with improved color mixing
US9386668B2 (en) 2010-09-30 2016-07-05 Ketra, Inc. Lighting control system
US9392663B2 (en) 2014-06-25 2016-07-12 Ketra, Inc. Illumination device and method for controlling an illumination device over changes in drive current and temperature
US9392660B2 (en) 2014-08-28 2016-07-12 Ketra, Inc. LED illumination device and calibration method for accurately characterizing the emission LEDs and photodetector(s) included within the LED illumination device
US9485813B1 (en) 2015-01-26 2016-11-01 Ketra, Inc. Illumination device and method for avoiding an over-power or over-current condition in a power converter
US9509525B2 (en) 2008-09-05 2016-11-29 Ketra, Inc. Intelligent illumination device
US9510416B2 (en) 2014-08-28 2016-11-29 Ketra, Inc. LED illumination device and method for accurately controlling the intensity and color point of the illumination device over time
US9557214B2 (en) 2014-06-25 2017-01-31 Ketra, Inc. Illumination device and method for calibrating an illumination device over changes in temperature, drive current, and time
US9578724B1 (en) 2013-08-20 2017-02-21 Ketra, Inc. Illumination device and method for avoiding flicker
US9651632B1 (en) 2013-08-20 2017-05-16 Ketra, Inc. Illumination device and temperature calibration method
US9736895B1 (en) 2013-10-03 2017-08-15 Ketra, Inc. Color mixing optics for LED illumination device
US9736903B2 (en) 2014-06-25 2017-08-15 Ketra, Inc. Illumination device and method for calibrating and controlling an illumination device comprising a phosphor converted LED
US9769899B2 (en) 2014-06-25 2017-09-19 Ketra, Inc. Illumination device and age compensation method
CN107489902A (en) * 2017-08-28 2017-12-19 武汉市金运科技开发有限公司 Internet of things mining lamp and structure setting method thereof
US10161786B2 (en) 2014-06-25 2018-12-25 Lutron Ketra, Llc Emitter module for an LED illumination device
US10210750B2 (en) 2011-09-13 2019-02-19 Lutron Electronics Co., Inc. System and method of extending the communication range in a visible light communication system

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4648131A (en) * 1983-10-07 1987-03-03 Ngk Insulators, Ltd. Work helmet having transmitter-receiver for light signal
US4809359A (en) * 1986-12-24 1989-02-28 Dockery Devan T System for extending the effective operational range of an infrared remote control system
US4819273A (en) * 1985-06-07 1989-04-04 Anderson Strathclyde Plc Mining machine control system
GB2254717A (en) * 1991-04-08 1992-10-14 Mannesmann Ag Wire-less control of lifting devices by infrared.
US5349463A (en) * 1990-08-17 1994-09-20 Victor Company Of Japan Optical radio repeater with signal quality detection
WO1995034963A1 (en) * 1994-06-16 1995-12-21 Iml Ltd. Free space communications system employing line of sight radiation

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4648131A (en) * 1983-10-07 1987-03-03 Ngk Insulators, Ltd. Work helmet having transmitter-receiver for light signal
US4819273A (en) * 1985-06-07 1989-04-04 Anderson Strathclyde Plc Mining machine control system
US4809359A (en) * 1986-12-24 1989-02-28 Dockery Devan T System for extending the effective operational range of an infrared remote control system
US5349463A (en) * 1990-08-17 1994-09-20 Victor Company Of Japan Optical radio repeater with signal quality detection
GB2254717A (en) * 1991-04-08 1992-10-14 Mannesmann Ag Wire-less control of lifting devices by infrared.
WO1995034963A1 (en) * 1994-06-16 1995-12-21 Iml Ltd. Free space communications system employing line of sight radiation

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2318939A (en) * 1996-11-01 1998-05-06 Richard James Harvey Infra-red identification device
US9276766B2 (en) 2008-09-05 2016-03-01 Ketra, Inc. Display calibration systems and related methods
US8521035B2 (en) 2008-09-05 2013-08-27 Ketra, Inc. Systems and methods for visible light communication
US8674913B2 (en) 2008-09-05 2014-03-18 Ketra, Inc. LED transceiver front end circuitry and related methods
US8773336B2 (en) 2008-09-05 2014-07-08 Ketra, Inc. Illumination devices and related systems and methods
US8886047B2 (en) 2008-09-05 2014-11-11 Ketra, Inc. Optical communication device, method and system
US9509525B2 (en) 2008-09-05 2016-11-29 Ketra, Inc. Intelligent illumination device
US9295112B2 (en) 2008-09-05 2016-03-22 Ketra, Inc. Illumination devices and related systems and methods
US9386668B2 (en) 2010-09-30 2016-07-05 Ketra, Inc. Lighting control system
US8749172B2 (en) 2011-07-08 2014-06-10 Ketra, Inc. Luminance control for illumination devices
US10210750B2 (en) 2011-09-13 2019-02-19 Lutron Electronics Co., Inc. System and method of extending the communication range in a visible light communication system
WO2013126585A1 (en) * 2012-02-21 2013-08-29 Ketra, Inc. System and method of extending the communication range in a visible light communication system
US9247605B1 (en) 2013-08-20 2016-01-26 Ketra, Inc. Interference-resistant compensation for illumination devices
US9237620B1 (en) 2013-08-20 2016-01-12 Ketra, Inc. Illumination device and temperature compensation method
US9332598B1 (en) 2013-08-20 2016-05-03 Ketra, Inc. Interference-resistant compensation for illumination devices having multiple emitter modules
US9345097B1 (en) 2013-08-20 2016-05-17 Ketra, Inc. Interference-resistant compensation for illumination devices using multiple series of measurement intervals
US9155155B1 (en) 2013-08-20 2015-10-06 Ketra, Inc. Overlapping measurement sequences for interference-resistant compensation in light emitting diode devices
US9651632B1 (en) 2013-08-20 2017-05-16 Ketra, Inc. Illumination device and temperature calibration method
US9578724B1 (en) 2013-08-20 2017-02-21 Ketra, Inc. Illumination device and method for avoiding flicker
US9736895B1 (en) 2013-10-03 2017-08-15 Ketra, Inc. Color mixing optics for LED illumination device
US9146028B2 (en) 2013-12-05 2015-09-29 Ketra, Inc. Linear LED illumination device with improved rotational hinge
US9668314B2 (en) 2013-12-05 2017-05-30 Ketra, Inc. Linear LED illumination device with improved color mixing
US9360174B2 (en) 2013-12-05 2016-06-07 Ketra, Inc. Linear LED illumination device with improved color mixing
US9736903B2 (en) 2014-06-25 2017-08-15 Ketra, Inc. Illumination device and method for calibrating and controlling an illumination device comprising a phosphor converted LED
US9557214B2 (en) 2014-06-25 2017-01-31 Ketra, Inc. Illumination device and method for calibrating an illumination device over changes in temperature, drive current, and time
US10161786B2 (en) 2014-06-25 2018-12-25 Lutron Ketra, Llc Emitter module for an LED illumination device
US9392663B2 (en) 2014-06-25 2016-07-12 Ketra, Inc. Illumination device and method for controlling an illumination device over changes in drive current and temperature
US9769899B2 (en) 2014-06-25 2017-09-19 Ketra, Inc. Illumination device and age compensation method
US9510416B2 (en) 2014-08-28 2016-11-29 Ketra, Inc. LED illumination device and method for accurately controlling the intensity and color point of the illumination device over time
US9392660B2 (en) 2014-08-28 2016-07-12 Ketra, Inc. LED illumination device and calibration method for accurately characterizing the emission LEDs and photodetector(s) included within the LED illumination device
US9485813B1 (en) 2015-01-26 2016-11-01 Ketra, Inc. Illumination device and method for avoiding an over-power or over-current condition in a power converter
US9237612B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a target lumens that can be safely produced by an illumination device at a present temperature
US9237623B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a maximum lumens that can be safely produced by the illumination device to achieve a target chromaticity
CN107489902A (en) * 2017-08-28 2017-12-19 武汉市金运科技开发有限公司 Internet of things mining lamp and structure setting method thereof

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