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WO2011067117A1 - Dispositif d'éclairage à del avec capteur de lumière et procédé de commande - Google Patents

Dispositif d'éclairage à del avec capteur de lumière et procédé de commande Download PDF

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Publication number
WO2011067117A1
WO2011067117A1 PCT/EP2010/067650 EP2010067650W WO2011067117A1 WO 2011067117 A1 WO2011067117 A1 WO 2011067117A1 EP 2010067650 W EP2010067650 W EP 2010067650W WO 2011067117 A1 WO2011067117 A1 WO 2011067117A1
Authority
WO
WIPO (PCT)
Prior art keywords
leds
led
lighting device
light sensor
operable
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.)
Ceased
Application number
PCT/EP2010/067650
Other languages
English (en)
Inventor
Simone Capeleto
Francesco Martini
Matteo Toscan
Lorenzo Roberto Trevisanello
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Osram SpA
Original Assignee
Osram GmbH
Osram SpA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Osram GmbH, Osram SpA filed Critical Osram GmbH
Publication of WO2011067117A1 publication Critical patent/WO2011067117A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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]
    • H05B45/20—Controlling the colour of the light
    • H05B45/22—Controlling the colour of the light using optical feedback
    • 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

  • LED lighting device with light sensor and control method
  • the description refers in general to solid-state lighting devices based on LED technology, and methods for controlling them.
  • Lighting applications that make use of light-emitting diode or LED technology take advantage of the efficiency, availability of different colors, and small dimensions of these devices.
  • these applications suffer from a drop-off in light emission due to LED ageing.
  • the conditions of use such as ambient temperature or the levels of current, influence the luminous flux of the LEDs.
  • devices that emit at different wavelengths exhibit different coefficients of temperature and current dependency, making it expensive in terms of control hardware and processing time to estimate the actual flux.
  • LED luminous flux in real time, giving a more accurate estimate of the decay of the LEDs together with an assessment of the effect of the conditions of use on the total flux.
  • optical feedback enables the colors to be modulated correctly.
  • One approach involves control by thermal feedback only, together with assessment of characteristics of the LEDs such as the ageing curve, luminosity as a function of temperature and current. Although such an approach makes it possible to reduce costs in terms of components, its drawback is that it requires dedicated hardware and software to operate the control. It also means that all the characteristics of the LEDs, including the decay curve, must be known.
  • a second approach involves control by means of thermal feedback and optical feedback, using a dedicated optical sensor.
  • the optical sensor can offer a good degree of accuracy in the light detection.
  • this approach has at least two main drawbacks, viz. the cost of the additional component and the need to obtain an optical coupling between the sensor and the emission area, which can be difficult to achieve because of the presence of other optical elements, electronic components and mechanical constraints.
  • the invention also relates to a method for controlling a lighting device having the features claimed in claim 10.
  • FIGS. 1 and 2 are circuit diagrams illustrating an embodiment of a lighting device in two operating conditions. Detailed description of embodiments
  • the proposed solution offers economical and fully integrated light detection using an LED as a light sensor.
  • the solution exploits the dual nature of LEDs, which work as light emitters when a forward voltage is applied to them, but as sensors when a reverse voltage is applied to them, because of the photoconductivity caused by generation of electron-hole pairs assisted by photons at the junction in the LED.
  • an LED that emits at a certain wavelength is sensitive to light radiation at shorter wavelengths, it can be used as a sensor for an LED emitting at shorter wavelengths and, more generally, for light emitted at shorter wavelengths.
  • an LED emitting in the red is sensitive to the entire visible spectrum with the exception of red light itself.
  • the red LED is included in solid-state lighting solutions of adjustable white type, RGB type for generating colors, and warm-white type for replacing incandescent bulbs. More generally, in systems using LEDs emitting at different wavelengths, the LED that emits at the longest wavelength can be used as a light sensor.
  • Figures 1 and 2 show the circuit diagram of a lighting device, indicated as a whole by reference 10, comprising an LED 16, in two different operating configurations.
  • the lighting device 10 comprises a drive source 11 as a supply circuit, in this example a current source, which is connected to the LED 16 by a first switch 12 located between the current source 11 and the anode of the LED 16 and by a second switch 13 located between the cathode of the LED 16 and ground.
  • the lighting device 10 comprises another supply circuit represented by a voltage source 17 connected via a positive clamp on itself to the cathode of the LED 16, through a fourth switch 15.
  • the anode of the LED 16 is also connected, by a third switch 14, to the input of a sense amplifier 18 which comprises a shunt resistor 19 to sense the current.
  • the switches 12, 13, 14, 15 identify a switching circuit and are controlled by a control circuit, which is implemented by the circuit which controls the lighting system.
  • Figure 1 shows a first working configuration of the lighting device 10, corresponding to a light-emitting state in which the first switch 12 and the second switch 13 are closed, allowing the drive source 11 to control the LED 16, by feeding it with a drive current I p and applying a forward bias .
  • the third switch 14 and the fourth switch 15 are open, isolating the voltage source 17 and the amplifier 18.
  • the LED 16 in this first configuration emits light.
  • FIG. 2 shows a second working configuration of the lighting device 10, corresponding to a light detecting state, in which the first switch 12 and the second switch 13 are open, isolating the drive source 11 from the rest of the circuit.
  • the fourth switch 15 is closed, so that this fourth switch 15 connects the voltage source 17 to the cathode of the LED 16, while the third switch 14 in the closed state connects the anode of the LED 16 to the amplifier 18 and to the shunt resistor 19 which is connected at the other end to a ground node.
  • the LED 16 is thus reverse-biased and therefore a reverse current flows through the LED 16, corresponding to a photocurrent I F toward the shunt resistor 19, causing a voltage drop across this resistor 19 which is amplified by the amplifier 18.
  • An output signal 20 from the amplifier 18 is proportional to the luminous flux which illuminates the surface of the LED 16 and generates the photocurrent I F .
  • the lighting device can be used as a sensor for compensating for LED ageing.
  • applications such as spotlights or downlights, which comprise LEDs emitting at different wavelengths, the LEDs are mounted close together.
  • the LEDs which emit at longer wavelengths can be used as sensors to monitor the ageing of the other LEDs.
  • This function is useful in LED systems for emitting adjustable white and warm white, because these systems include a red LED which can be used to monitor the luminous flux of the main emitter, e.g. the white LED.
  • the ageing of the LED can be compensated for by adjusting the current in order to keep the flux constant.
  • Optical coupling of the sensor LED with the other, emitting LEDs is ensured by the proximity of the LEDs.
  • the lighting device can also be used as a sensor for controlling the color mixing of the LEDs.
  • RGB applications and for emitting adjustable white where the LEDs are arranged close together, it is also possible to use the red LED to detect the light emitted by the other LEDs, monitoring the light by turning the emitting LEDs on one by one, that is in sequential mode, in order to calculate the color co-ordinates of all the LEDs by capturing their photocurrent values. Because the flux of the red LED cannot be detected, it can be derived from the data, stored in the controller, of the characteristics of the LEDs. Calibration is performed at predetermined time intervals. Optical coupling of the sensor LED with the other, emitting LEDs is ensured by the proximity of the LEDs.
  • the lighting device according to the invention can also be used as a sensor for monitoring and compensating for thermal drifts which influence the performance of the LEDs.
  • Using the same technique as explained for controlling the color mix described above it is possible to monitor the intensity of each LED during heating of the system and the current in the various channels can be controlled in order to keep the color temperature or color coordinates constant.
  • the optical coupling of the sensor LED with the other, emitting LEDs is ensured by the proximity of the LEDs.
  • the lighting device according to the invention can also be used as an ambient light sensor.
  • the LEDs are coupled to an optical element such as a reflector and/or lens. Ambient light is thus focused onto the LEDs. If the lighting unit is equipped with a red LED, this ambient light can be detected and used to control luminosity. For example, in road lighting applications, the LEDs can be damped as a function of the ambient light until the light is extinguished. In this way it is possible to improve the efficiency of the system by avoiding energy consumption when no luminous flux is required.
  • the solution set out in this description makes it possible to obtain a lighting device that is advantageous in that it removes the necessity of an optical sensor and its associated coupling system. This also means that the unit can be made more compact.
  • the use of an LED belonging to the system has the advantage of allowing a good coupling to be obtained between the LEDs for emission and detection.
  • the resulting lighting system is highly reliable because of the compensation for ageing. It is also possible to achieve highly accurate chromatic properties in color mixing applications. It is possible to achieve high efficiency of the system in ambient light detection and smart control of luminosity.

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

L'invention concerne un dispositif d'éclairage comprenant une pluralité de DEL (16) et au moins un premier circuit d'alimentation (11) conçu pour fournir un courant de commande (Ip) pour transmettre une polarisation à une ou plusieurs DEL dans ladite pluralité de DEL (16) et comprenant, dans ladite pluralité de DEL, au moins une DEL (16) qui peut fonctionner comme capteur de lumière, un second circuit d'alimentation (17) conçu pour appliquer une polarisation inverse à ladite ou auxdites DEL (16) qui peuvent fonctionner comme capteur de lumière, et un circuit (18, 19, 20) servant à détecter un photocourant (IF) de ladite ou desdites DEL (16) qui peuvent fonctionner comme capteur de lumière.
PCT/EP2010/067650 2009-12-04 2010-11-17 Dispositif d'éclairage à del avec capteur de lumière et procédé de commande Ceased WO2011067117A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITTO20090956 2009-12-04
ITTO2009A000956 2009-12-04

Publications (1)

Publication Number Publication Date
WO2011067117A1 true WO2011067117A1 (fr) 2011-06-09

Family

ID=42312963

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2010/067650 Ceased WO2011067117A1 (fr) 2009-12-04 2010-11-17 Dispositif d'éclairage à del avec capteur de lumière et procédé de commande

Country Status (1)

Country Link
WO (1) WO2011067117A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10895435B2 (en) 2017-02-27 2021-01-19 Kurt S. SCHULZ Firearm simulator targets and firearm simulation systems
US11112204B2 (en) 2014-12-16 2021-09-07 Kurt S. SCHULZ Firearm simulators
RU2774503C1 (ru) * 2021-12-10 2022-06-21 Общество с ограниченной ответственностью "Всесоюзный научно-исследовательский светотехнический институт имени С.И. Вавилова" Способ измерения распределения освещенности дорожного покрытия и автоматизированный комплекс для его реализации
CN120390339A (zh) * 2025-06-30 2025-07-29 杭州天都照明电器有限公司 基于环境光强度的照明设备自适应调节方法及系统

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008152922A1 (fr) * 2007-06-15 2008-12-18 Sharp Kabushiki Kaisha Système d'éclairage à semi-conducteur

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008152922A1 (fr) * 2007-06-15 2008-12-18 Sharp Kabushiki Kaisha Système d'éclairage à semi-conducteur

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11112204B2 (en) 2014-12-16 2021-09-07 Kurt S. SCHULZ Firearm simulators
US10895435B2 (en) 2017-02-27 2021-01-19 Kurt S. SCHULZ Firearm simulator targets and firearm simulation systems
RU2774503C1 (ru) * 2021-12-10 2022-06-21 Общество с ограниченной ответственностью "Всесоюзный научно-исследовательский светотехнический институт имени С.И. Вавилова" Способ измерения распределения освещенности дорожного покрытия и автоматизированный комплекс для его реализации
CN120390339A (zh) * 2025-06-30 2025-07-29 杭州天都照明电器有限公司 基于环境光强度的照明设备自适应调节方法及系统

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