EP1562406B1 - Method and apparatus for monitoring the condition of LEDs - Google Patents
Method and apparatus for monitoring the condition of LEDs Download PDFInfo
- Publication number
- EP1562406B1 EP1562406B1 EP05100565A EP05100565A EP1562406B1 EP 1562406 B1 EP1562406 B1 EP 1562406B1 EP 05100565 A EP05100565 A EP 05100565A EP 05100565 A EP05100565 A EP 05100565A EP 1562406 B1 EP1562406 B1 EP 1562406B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- leds
- minimum
- control current
- maximum
- led illuminator
- Prior art date
- 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.)
- Not-in-force
Links
Images
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
- H05B45/58—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits involving end of life detection of LEDs
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/10—Controlling the intensity of the light
- H05B45/12—Controlling the intensity of the light using optical feedback
Definitions
- the invention relates to a method according to the preamble of claim 1 for monitoring the condition of a LED illuminator comprising one or more light emitting diodes and to an apparatus according to the preamble of claim 7 for monitoring the condition of a LED illuminator comprising one or more light emitting diodes.
- LEDs light emitting diodes
- exit signs and safety illuminators the condition of these must be monitored according to the regulations.
- condition monitoring of LED illuminators a problem arises from how to provide automated and reliable measurement of the condition of the lighting fixture, because a LED may lose its lighting capacity gradually; the amount of current it consumes does not change but remains at the original level. Therefore measurement of current or voltage, i.e. electric parameters, does not provide reliable information about the condition of LEDs.
- Patent publication US 5,783,909 discloses an apparatus for maintaining LED luminous intensity by using a luminous feedback.
- the object of the invention is achieved by a method characterized in that the method comprises the following steps: controlling the LEDs by means of pulsed current, measuring the light output of the LEDs or the LED illuminator by means of one or more light sensors during the minimum and maximum levels of the control current, separating two separate measurement signals from the light outputs measured during the minimum and maximum levels of the pulsed control current, and making conclusions on the operating condition of the LEDs or the LED illuminator by comparing the measurement signals corresponding to the minimum and maximum control current levels with each other.
- the object of the invention is further achieved by an apparatus characterized in that the apparatus comprises current supply means for supplying pulsed control current to the LEDs and/or the LED illuminator, one or more light sensors for measuring the light output of the LEDs and/or the LED illuminator, and signal processing means for processing signals received from the light sensor.
- the apparatus comprises current supply means for supplying pulsed control current to the LEDs and/or the LED illuminator, one or more light sensors for measuring the light output of the LEDs and/or the LED illuminator, and signal processing means for processing signals received from the light sensor.
- the invention is based on controlling a LED illuminator comprising one or more light emitting diodes with pulsed current, whereby the LEDs are alternately on and off, or they burn with a brighter or a dimmer light.
- the light output of the LEDs or the LED illuminator thus controlled is measured by means of one or more light sensors installed in connection with the illuminator.
- the light sensor produces a measurement signal that varies substantially in accordance with the pulsed current.
- the measurement signal is divided into two separate signals, one of which corresponds to the minimum current level and the other one to the maximum level.
- the two separated measurement signals are then compared with each other and, as a result, a difference between the light outputs of the LEDs during the minimum and maximum levels of the pulsed current is obtained.
- the difference becomes smaller and finally reaches zero when there is no output from the LEDs.
- the light intensity observed by means of the light sensor consists of the sum of the light output produced by the LEDs and the ambient light, whereas when the LEDs are off, the measured light intensity consists of the ambient light alone, if the minimum level of the pulsed current is zero. Consequently, the difference between these two separate measurement results obtained from the light sensor corresponds to the light output produced by the LEDs at a particular moment.
- An advantage of the method and apparatus of the invention is that it enables ambient outside light to be eliminated from the measurement result of the light sensor and thus the monitoring of the operating condition of the illuminator is no longer distorted by ambient light.
- the method and apparatus of the invention provide a reliable solution for monitoring the condition of LEDs independently of the electric parameters of the LEDs and the LED illuminator.
- Figure 1 shows a schematic view of a LED illuminator of the present invention comprising means for monitoring the operating condition of LEDs.
- the LED illuminator in question comprises one or more LEDs 2, whose operation is controlled by current supply means 6.
- the current supply means 6 are configured to supply pulsed current to the LEDs whereby the LEDs are alternately on and off.
- the frequency of this kind of pulsed current may vary from 20 to 500 Hz, for example.
- Figure 1 shows an example of pulsed current 14. At a maximum level 15 of the pulsed current 14 the LEDs 2 are on and produce light, whereas at a minimum level 13 they are off and do not produce light.
- the frequency of the pulsed current 14 may be set as required for a particular place and/or purpose of use of the illuminator. Moreover, the amplitude of the pulsed current 14, which represents the intensity of the current supplied to the LEDs 2, may be selected as required in each case. It is also possible to change the pulse ratio of the current to be supplied to the LEDs 2 by adjusting the ratio of the duration of the maximum level 15, i.e. when the LEDs 2 receive current, to the duration of the minimum level 13, i.e. when the LEDs 2 do not receive current. By changing the pulse ratio it is possible to adjust the brightness of the illuminator so that the duration of the maximum level 15 increases in relation to the duration of the minimum level 13.
- the pulsed current 14 is generated by means of a pulse oscillator, although any other device capable of producing pulsed current can be used as well. It is also possible to set the current impulse supplied to the LEDs 2 so that also at the minimum level 13 the LEDs 2 receive current, which due to its pulsed nature is lower than the current supplied at the maximum level 15. The following example, however, assumes that at the minimum level 13 there is zero current.
- the LED illuminator is provided with a light sensor 4 installed therein to measure light intensity inside the illuminator.
- the intensity of light inside the illuminator is always the sum of ambient light, i.e. that coming from outside the illuminator, and the light output produced by the LEDs 2.
- the light output of the LEDs 2 is zero because the LEDs 2 are off and thus do not emit light, the light intensity inside the illuminator consisting only of the ambient light.
- the LEDs emit light and therefore light intensity inside the illuminator is the sum of the ambient light and the light output produced by the LEDs 2.
- the light sensor 4 thus automatically measures ambient light, whereas at the maximum level 15 it measures both the ambient light and the light produced by the LEDs 2.
- the separating means 18 may consist of a switch, for example, that operates in response to a pulsed current signal received from current supply means 6, as shown Figure 1 .
- the light intensity measurement signals corresponding to the maximum level 15 and the minimum level 13 of the pulsed current 14 are compared with each other.
- the comparison preferably takes place by calculating the difference between the two separate measurement results in subtraction means 16. In practice this is carried out by taking voltage samples from the separated measurement signals of the light sensor 4 and by supplying the samples to what are known as memory capacitors 10, 12.
- the voltage sample of the measurement signal representing the minimum level 13 of the pulsed current 14, i.e. when the LEDs are off, is stored in memory 10.
- the voltage sample of the measurement signal representing the maximum level 15 of the pulsed current 14, i.e. when the LEDs are on is stored in memory 12.
- the difference between them is calculated.
- Another alternative is to temporally average these two separate signal levels stored in memories 10, 12 by means of suitable averaging means whereby sudden changes of short duration are filtered off from the measurement results.
- the switch 18 operating in response to pulsed current 14 guides the measurement signal obtained from the light sensor 14 to memory 12 when the LEDs are on and to memory 10 when the LEDs are off.
- the ambient light intensity is filtered off from the measurement results when the difference between these two separate measurement signals is calculated.
- the value representing the minimum current level 13 is zero, i.e. the LEDs do not receive current.
- the value obtained from the subtraction means 16, which represents the operating condition of the LEDs 2 or the LEDs of the LED illuminator as a whole, can be compared with a predetermined limit value. Since LEDs tend to become dimmer in long-term use, the comparison with the predetermined limit value enables fully automated monitoring of the operating condition of the LEDs. Thus, when the value obtained from the subtraction means 16, which represents the operating condition of the LEDs, drops, an alarm can be raised by means of an alarm device (not shown) connected to the comparison means 8. After the alarm the operating condition of the LED illuminator can be restored by means of service operations or by replacing the illuminator with a new one.
- the monitoring of the operating condition of the LEDs can be further facilitated and simplified by connecting the pulsed current 14 supply means 6 and the light sensor 4 to a microprocessor and/or a computer, which then functions as the comparison means 8.
- the processing of the measurement signal obtained from the light sensor 4 may be carried out totally or partly by the microprocessor. In that case the separation of the measurement signals corresponding to the minimum level 13 and the maximum level 15 of the pulsed current 14, their storage to memories 10, 12, their comparison, and the raising of the alarm in response to a predetermined limit value may be carried out easily by means of the microprocessor and/or computer and a software, if any.
- the method of the present invention for monitoring the operating condition of a LED illuminator can be carried out.
- the light output of a LED illuminator controlled by pulsed current 14 is measured by means of a light sensor 4 installed inside the illuminator. Due to the pulsed current, light output varies in accordance with variations in the current, the frequency of a measurement signal obtained from the light sensor 4 substantially corresponding to the frequency of the pulsed current.
- the measurement signal is further supplied to the comparison means 8 to separate two separate measurement signals from the signal obtained, one of the signals corresponding to the light intensity of the LED illuminator at the minimum level 13 and the other one to its intensity at the maximum level 15 of the pulsed current 14.
Landscapes
- Circuit Arrangement For Electric Light Sources In General (AREA)
Description
- The invention relates to a method according to the preamble of claim 1 for monitoring the condition of a LED illuminator comprising one or more light emitting diodes and to an apparatus according to the preamble of claim 7 for monitoring the condition of a LED illuminator comprising one or more light emitting diodes.
- Regular control of the condition of all types of safety illuminators is prescribed by regulations. Automated condition monitoring of safety lighting fixtures provided with an incandescent or a discharge lamp is a standard procedure. The operating condition of these lamps can be easily established by measuring electric parameters of the lamps.
- Today lighting equipment employing light emitting diodes (LEDs) is ever increasingly used in exit signs and safety illuminators. Also the condition of these must be monitored according to the regulations. In prior art arrangements for condition monitoring of LED illuminators, a problem arises from how to provide automated and reliable measurement of the condition of the lighting fixture, because a LED may lose its lighting capacity gradually; the amount of current it consumes does not change but remains at the original level. Therefore measurement of current or voltage, i.e. electric parameters, does not provide reliable information about the condition of LEDs.
- It is also possible to try to measure the condition of LEDs by measuring the light produced by them from the outside of the lighting fixture. However, if the lighting fixture contains a plural number of LEDs and/or is placed in an environment with a bright background light, this is difficult because due to the light coming from the outside or from adjacent LEDs, the measuring results are unreliable.
Patent publication US 5,783,909 discloses an apparatus for maintaining LED luminous intensity by using a luminous feedback. - It is therefore an object of the invention to provide a method according to claim 1 and an apparatus according to claim 7 to enable the above problems to be solved. The object of the invention is achieved by a method characterized in that the method comprises the following steps: controlling the LEDs by means of pulsed current, measuring the light output of the LEDs or the LED illuminator by means of one or more light sensors during the minimum and maximum levels of the control current, separating two separate measurement signals from the light outputs measured during the minimum and maximum levels of the pulsed control current, and making conclusions on the operating condition of the LEDs or the LED illuminator by comparing the measurement signals corresponding to the minimum and maximum control current levels with each other. The object of the invention is further achieved by an apparatus characterized in that the apparatus comprises current supply means for supplying pulsed control current to the LEDs and/or the LED illuminator, one or more light sensors for measuring the light output of the LEDs and/or the LED illuminator, and signal processing means for processing signals received from the light sensor.
- The preferred embodiments of the invention are disclosed in the dependent claims.
- The invention is based on controlling a LED illuminator comprising one or more light emitting diodes with pulsed current, whereby the LEDs are alternately on and off, or they burn with a brighter or a dimmer light. The light output of the LEDs or the LED illuminator thus controlled is measured by means of one or more light sensors installed in connection with the illuminator. The light sensor produces a measurement signal that varies substantially in accordance with the pulsed current. The measurement signal is divided into two separate signals, one of which corresponds to the minimum current level and the other one to the maximum level. The two separated measurement signals are then compared with each other and, as a result, a difference between the light outputs of the LEDs during the minimum and maximum levels of the pulsed current is obtained. As the light output of the LEDs degrades, the difference becomes smaller and finally reaches zero when there is no output from the LEDs. When the LEDs are on, the light intensity observed by means of the light sensor consists of the sum of the light output produced by the LEDs and the ambient light, whereas when the LEDs are off, the measured light intensity consists of the ambient light alone, if the minimum level of the pulsed current is zero. Consequently, the difference between these two separate measurement results obtained from the light sensor corresponds to the light output produced by the LEDs at a particular moment.
- An advantage of the method and apparatus of the invention is that it enables ambient outside light to be eliminated from the measurement result of the light sensor and thus the monitoring of the operating condition of the illuminator is no longer distorted by ambient light. In addition, the method and apparatus of the invention provide a reliable solution for monitoring the condition of LEDs independently of the electric parameters of the LEDs and the LED illuminator.
- In the following, the invention will be described in greater detail with reference to the preferred embodiments and the accompanying drawing, in which
-
Figure 1 is a schematic view of a LED illuminator whose operating condition is monitored in accordance with the invention. -
Figure 1 shows a schematic view of a LED illuminator of the present invention comprising means for monitoring the operating condition of LEDs. The LED illuminator in question comprises one ormore LEDs 2, whose operation is controlled by current supply means 6. The current supply means 6 are configured to supply pulsed current to the LEDs whereby the LEDs are alternately on and off. The frequency of this kind of pulsed current may vary from 20 to 500 Hz, for example.Figure 1 shows an example ofpulsed current 14. At amaximum level 15 of thepulsed current 14 theLEDs 2 are on and produce light, whereas at aminimum level 13 they are off and do not produce light. - The frequency of the
pulsed current 14 may be set as required for a particular place and/or purpose of use of the illuminator. Moreover, the amplitude of thepulsed current 14, which represents the intensity of the current supplied to theLEDs 2, may be selected as required in each case. It is also possible to change the pulse ratio of the current to be supplied to theLEDs 2 by adjusting the ratio of the duration of themaximum level 15, i.e. when theLEDs 2 receive current, to the duration of theminimum level 13, i.e. when theLEDs 2 do not receive current. By changing the pulse ratio it is possible to adjust the brightness of the illuminator so that the duration of themaximum level 15 increases in relation to the duration of theminimum level 13. In this embodiment thepulsed current 14 is generated by means of a pulse oscillator, although any other device capable of producing pulsed current can be used as well. It is also possible to set the current impulse supplied to theLEDs 2 so that also at theminimum level 13 theLEDs 2 receive current, which due to its pulsed nature is lower than the current supplied at themaximum level 15. The following example, however, assumes that at theminimum level 13 there is zero current. - According to the present invention, the LED illuminator is provided with a light sensor 4 installed therein to measure light intensity inside the illuminator. The intensity of light inside the illuminator is always the sum of ambient light, i.e. that coming from outside the illuminator, and the light output produced by the
LEDs 2. At theminimum level 13 of thepulsed supply current 14 the light output of theLEDs 2 is zero because theLEDs 2 are off and thus do not emit light, the light intensity inside the illuminator consisting only of the ambient light. At themaximum level 15 of thepulsed supply current 14 the LEDs emit light and therefore light intensity inside the illuminator is the sum of the ambient light and the light output produced by theLEDs 2. At theminimum level 13 of thepulsed current 14 the light sensor 4 thus automatically measures ambient light, whereas at themaximum level 15 it measures both the ambient light and the light produced by theLEDs 2. - From the measurement results obtained from the sensor 4, two separate measurement signals are separated, one of which corresponds to the measurement result obtained at the
maximum level 15 of thepulsed current 14 and the other to the measurement result obtained at theminimum level 13. These two separate measurement signals are separated by means of separating means 18 provided in comparison means 8. The separating means 18 may consist of a switch, for example, that operates in response to a pulsed current signal received from current supply means 6, as shownFigure 1 . - Having been supplied to the comparison means and separated there, the light intensity measurement signals corresponding to the
maximum level 15 and theminimum level 13 of thepulsed current 14 are compared with each other. The comparison preferably takes place by calculating the difference between the two separate measurement results in subtraction means 16. In practice this is carried out by taking voltage samples from the separated measurement signals of the light sensor 4 and by supplying the samples to what are known asmemory capacitors minimum level 13 of thepulsed current 14, i.e. when the LEDs are off, is stored inmemory 10. The voltage sample of the measurement signal representing themaximum level 15 of thepulsed current 14, i.e. when the LEDs are on, is stored inmemory 12. Next, to compare the voltage values stored inmemories memories Figure 1 are used, theswitch 18 operating in response to pulsed current 14 guides the measurement signal obtained from thelight sensor 14 tomemory 12 when the LEDs are on and tomemory 10 when the LEDs are off. - Since the measurement signal representing the
minimum level 13 of thepulsed current 14 contains ambient light intensity alone and the signal representing themaximum level 15 contains both ambient light intensity and light output created by the LEDs, the ambient light intensity is filtered off from the measurement results when the difference between these two separate measurement signals is calculated. As a result, only the values of the light output produced by the LEDs are left, and in this embodiment the value representing the minimumcurrent level 13 is zero, i.e. the LEDs do not receive current. Thus by calculating the difference between these two measurement results, it is possible to determine the light output and thereby also the condition of the LEDs and/or the LED illuminator on a continuous basis. - The value obtained from the subtraction means 16, which represents the operating condition of the
LEDs 2 or the LEDs of the LED illuminator as a whole, can be compared with a predetermined limit value. Since LEDs tend to become dimmer in long-term use, the comparison with the predetermined limit value enables fully automated monitoring of the operating condition of the LEDs. Thus, when the value obtained from the subtraction means 16, which represents the operating condition of the LEDs, drops, an alarm can be raised by means of an alarm device (not shown) connected to the comparison means 8. After the alarm the operating condition of the LED illuminator can be restored by means of service operations or by replacing the illuminator with a new one. - The monitoring of the operating condition of the LEDs can be further facilitated and simplified by connecting the pulsed current 14 supply means 6 and the light sensor 4 to a microprocessor and/or a computer, which then functions as the comparison means 8. The processing of the measurement signal obtained from the light sensor 4 may be carried out totally or partly by the microprocessor. In that case the separation of the measurement signals corresponding to the
minimum level 13 and themaximum level 15 of the pulsed current 14, their storage tomemories - With the apparatus described above the method of the present invention for monitoring the operating condition of a LED illuminator can be carried out. According to the method the light output of a LED illuminator controlled by pulsed current 14 is measured by means of a light sensor 4 installed inside the illuminator. Due to the pulsed current, light output varies in accordance with variations in the current, the frequency of a measurement signal obtained from the light sensor 4 substantially corresponding to the frequency of the pulsed current. The measurement signal is further supplied to the comparison means 8 to separate two separate measurement signals from the signal obtained, one of the signals corresponding to the light intensity of the LED illuminator at the
minimum level 13 and the other one to its intensity at themaximum level 15 of the pulsed current 14. These two separated measurement signals are stored in theirrespective memories - It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. Therefore the invention and its embodiments are not restricted to the above examples, but may vary within the scope of the accompanying claims.
Claims (10)
- A method for monitoring the condition of a LED illuminator comprising one or more light emitting diodes comprising the following steps:controlling the LEDs (2) by means of pulsed current (14) comprising a minimum level (13) and a maximum level (15);measuring the light output of the LEDs (2) or the LED illuminator by means of one or more light sensors (4) during the minimum (13) and maximum (15) levels of the pulsed control current (14);separating from the light outputs measured during the minimum (13) and maximum (15) levels of the pulsed control current (14) two separate measurement signals,characterized in that the method further comprises
calculating the difference of said measurement signals corresponding to the minimum (13) and maximum (15) levels of the control current (14); and
comparing the calculated difference of the measurement signals corresponding to the minimum (13) and maximum (15) levels of the control current (14) to a predetermined limit value for monitoring the condition of the LED illuminator. - A method according to claim 1, characterized in that it further comprises a step of averaging the measurement signals corresponding to the minimum (13) and maximum (15) levels of the control current (14) for a predetermined period before making conclusions about the operating condition of the LEDs or the LED illuminator.
- A method according to claim 1 or 2, characterized in that the method further comprises a step of raising an alarm when the result obtained on the basis of the comparison/difference of the measurement signals corresponding to the minimum (13) and maximum (15) levels of the control current (14) is below the predetermined limit value.
- A method according to any one of the preceding claims, characterized in that the measurement signals received from the light sensors (4) are processed totally or partly by means of a microprocessor for determining the operating condition of the LEDs and/or the LED illuminator.
- An apparatus for monitoring the condition of a LED illuminator comprising one or more light emitting diodes (2), current supply means (6) for supplying pulsed control current to the LEDs and/or the LED illuminator, one or more light sensors installed inside the LED illuminator for measuring the light output of the LEDs and/or the LED illuminator, and signal processing means (8) having separation means (18) for separating light intensities measured by the light sensor (4) during the minimum (13) and maximum (15) levels of the pulsed control current (14) from one another, characterized in that the signal processing means (8) further comprise subtraction means (16) for determining the difference between the light output results measured during the minimum (13) and maximum (15) levels of the control current and means for comparing the difference between the light output results measured during the minimum (13) and maximum (15) levels of the control current to a predetermined limit value for monitoring the condition of the LED illuminator.
- An apparatus according to claim 5, characterized in that the current supply means (6) for supplying pulsed control current to the LEDs and/or to the LED illuminator comprise a pulse oscillator.
- An apparatus according to claim 5 or 6, characterized in that the signal processing means (8) further comprise memory (12) for storing a measurement signal received during the maximum level (15) of the pulsed control current (14) and memory (10) for storing a measurement signal received during the minimum level (13) of the pulsed control current (14).
- An apparatus according to any one of claims 5 to 7, characterized in that the apparatus further comprises an alarm device for raising an alarm when the difference between the light output results measured during the minimum (13) and maximum (15) levels of the control current is below the predetermined limit value.
- An apparatus according to any one of claims 5 to 8, characterized in that a microprocessor comprises signal processing means (8, 18, 10, 12, 16).
- An apparatus according to any one of claims 5 to 9, characterized in that a computer and/or computer software comprise signal processing means (8, 18, 10, 12, 16).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FI20040165A FI116356B (en) | 2004-02-03 | 2004-02-03 | Condition monitoring system |
FI20040165 | 2004-02-03 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1562406A1 EP1562406A1 (en) | 2005-08-10 |
EP1562406B1 true EP1562406B1 (en) | 2008-03-05 |
Family
ID=31725649
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP05100565A Not-in-force EP1562406B1 (en) | 2004-02-03 | 2005-01-28 | Method and apparatus for monitoring the condition of LEDs |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1562406B1 (en) |
DE (1) | DE602005005095T8 (en) |
FI (1) | FI116356B (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007036509A1 (en) * | 2005-09-27 | 2007-04-05 | Siemens Aktiengesellschaft | Method and device for monitoring the light signal from an electrooptical light element, in particular a high-current led, which is used for railway purposes, of a safe railway signal |
DE102005051212A1 (en) * | 2005-10-26 | 2007-05-03 | Bayerische Motoren Werke Ag | Illuminant function monitoring method for use in motor vehicle, involves modulating luminance of illuminant by measuring operating parameter of illuminant, where time of measurement is synchronized with control of illuminant |
DE102007043416B4 (en) * | 2007-09-12 | 2009-09-17 | P.E.R. Flucht- Und Rettungsleitsysteme Gmbh | Emergency lighting method and system |
DE102007045259A1 (en) * | 2007-09-21 | 2009-04-02 | Continental Automotive Gmbh | Method and device for detecting the light output emitted by an LED light source |
DE102007049618A1 (en) | 2007-10-17 | 2009-04-23 | Audi Ag | Device and method for determining an operating parameter of at least one light source of a light source of a motor vehicle |
DE102008034524B4 (en) * | 2008-07-24 | 2019-12-05 | Tridonic Gmbh & Co Kg | emergency pack |
WO2011154876A1 (en) * | 2010-06-08 | 2011-12-15 | Koninklijke Philips Electronics N.V. | Failsafe lighting system |
DE102016205529A1 (en) * | 2016-04-04 | 2017-10-05 | Osram Gmbh | Method for measuring light |
US9648697B1 (en) * | 2016-04-19 | 2017-05-09 | Leviton Manufacturing Co., Inc. | Brightness monitoring for LED failures and daylighting target adjusting |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5783909A (en) * | 1997-01-10 | 1998-07-21 | Relume Corporation | Maintaining LED luminous intensity |
GB9708861D0 (en) * | 1997-04-30 | 1997-06-25 | Signal House Limited | Traffic signals |
DE59911260D1 (en) * | 1998-07-23 | 2005-01-20 | Siemens Ag | Traffic signal system and method for monitoring the traffic signal system |
WO2003009647A1 (en) * | 2001-07-18 | 2003-01-30 | Power Signal Technologies, Inc. | Solid state traffic light with predictive failure analysis |
US6836260B2 (en) * | 2001-07-31 | 2004-12-28 | Eastman Kodak Company | Light emitting flat-panel display |
-
2004
- 2004-02-03 FI FI20040165A patent/FI116356B/en not_active IP Right Cessation
-
2005
- 2005-01-28 EP EP05100565A patent/EP1562406B1/en not_active Not-in-force
- 2005-01-28 DE DE602005005095T patent/DE602005005095T8/en active Active
Also Published As
Publication number | Publication date |
---|---|
FI116356B (en) | 2005-10-31 |
DE602005005095D1 (en) | 2008-04-17 |
DE602005005095T8 (en) | 2009-05-20 |
DE602005005095T2 (en) | 2009-01-29 |
EP1562406A1 (en) | 2005-08-10 |
FI20040165A (en) | 2005-08-04 |
FI20040165A0 (en) | 2004-02-03 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP1562406B1 (en) | Method and apparatus for monitoring the condition of LEDs | |
TWI475926B (en) | Light emitting diode system | |
TWI461627B (en) | Light emitting unit arrangement and control system and method thereof | |
JP4609327B2 (en) | Emergency lighting system | |
KR101124478B1 (en) | dimming control apparatus for LED lighting system that being adjustable illuminance | |
US10436584B2 (en) | Level with audio and/or visual indicators | |
KR100970613B1 (en) | Control apparatus and method of a led lamp | |
MXPA03001561A (en) | Luminaire diagnostic and configuration identification system. | |
CN104938034B (en) | Control the method and illuminator of illuminator | |
CN104918357B (en) | Light modulating device and the illuminator using the light modulating device | |
US9157813B2 (en) | Device for outputting temperature information | |
EP2464197B1 (en) | System for manufacturing power supply unit and method for manufacturing power supply unit, and flicker measurement apparatus | |
CN112954850A (en) | Classroom lamp brightness control method and device and classroom lamp | |
CN115426745A (en) | Intelligent lamp band detection method, circuit and device and intelligent lamp band | |
CN101089732B (en) | Lighting device for exposal | |
JP7163292B2 (en) | Systems and methods for determining health status of dimmable pulsed LED light strings | |
JP2003347068A (en) | Lighting control device | |
KR101780149B1 (en) | Led lighting apparatus having function of dimming | |
US20140103932A1 (en) | System and method for light intensity monitoring | |
CN104982094A (en) | Lighting system and method for determining functional state of lighting system | |
JP2002195882A (en) | Luminous body inspection device | |
JP2009081008A (en) | Lighting state display device, and lighting state display system | |
KR100639350B1 (en) | Apparatus and method for detecting wickedness of a street light | |
KR101708185B1 (en) | Energy-saving exit guide lights | |
JP4634107B2 (en) | Battery floodlight |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU MC NL PL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL BA HR LV MK YU |
|
17P | Request for examination filed |
Effective date: 20060117 |
|
AKX | Designation fees paid |
Designated state(s): CH DE FR LI NL |
|
17Q | First examination report despatched |
Effective date: 20070305 |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: TEKNOWARE OY |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): CH DE FR LI NL |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
REF | Corresponds to: |
Ref document number: 602005005095 Country of ref document: DE Date of ref document: 20080417 Kind code of ref document: P |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: NV Representative=s name: WERNER BRUDERER PATENTANWALT |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20081208 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: NV Representative=s name: FREI PATENTANWALTSBUERO AG |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 12 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: PLFP Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20170116 Year of fee payment: 13 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: CH Payment date: 20180118 Year of fee payment: 14 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: FR Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20180131 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: ST Effective date: 20180928 |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PCAR Free format text: NEW ADDRESS: POSTFACH, 8032 ZUERICH (CH) |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: PL |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R079 Ref document number: 602005005095 Country of ref document: DE Free format text: PREVIOUS MAIN CLASS: H05B0033080000 Ipc: H05B0045000000 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LI Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20190131 Ref country code: CH Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20190131 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20200121 Year of fee payment: 16 Ref country code: NL Payment date: 20200120 Year of fee payment: 16 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R119 Ref document number: 602005005095 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MM Effective date: 20210201 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20210201 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: DE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20210803 |