EP2258146A1 - System and method for controlling leds - Google Patents

System and method for controlling leds

Info

Publication number
EP2258146A1
EP2258146A1 EP09726563A EP09726563A EP2258146A1 EP 2258146 A1 EP2258146 A1 EP 2258146A1 EP 09726563 A EP09726563 A EP 09726563A EP 09726563 A EP09726563 A EP 09726563A EP 2258146 A1 EP2258146 A1 EP 2258146A1
Authority
EP
European Patent Office
Prior art keywords
leds
pseudo
value
led
color
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.)
Granted
Application number
EP09726563A
Other languages
German (de)
French (fr)
Other versions
EP2258146B1 (en
Inventor
Eduardo Pereira
Michael Zimmermann
Yves Schenker
Adrian Betschart
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.)
Tridonic AG
Original Assignee
Tridonic AG
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 Tridonic AG filed Critical Tridonic AG
Publication of EP2258146A1 publication Critical patent/EP2258146A1/en
Application granted granted Critical
Publication of EP2258146B1 publication Critical patent/EP2258146B1/en
Not-in-force legal-status Critical Current
Anticipated expiration legal-status Critical

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

Definitions

  • the present invention generally relates to the generation of a light color by mixing a plurality of light emitting diodes (LEDs). More particularly, the invention is directed to the generation of a desired color and to the control of LEDs in order to obtain the desired color by mixing the light produced by the respective LEDs.
  • LEDs light emitting diodes
  • Prior art US 6552495 Bl discloses a control system for generating a desired light color on the basis of three red, green and blue LEDs.
  • the system comprises a sensor for- measuring the color coordinates of the light color generated by the three LEDs.
  • a transformation module is adapted to convert said color coordinates to another color space. Reference color coordinates corresponding to the desired light and expressed in the second color space are provided by a further transformation module. Error color coordinates between the desired light color coordinates and the generated light color coordinates are then generated and fed to a driver module configured to generate drive signals I R , I G , I B for driving the LEDs.
  • the reference value of the desired color has only three coordinates X, Y, Z, while four output signals have to be produced to drive the three LEDs and the additional one.
  • said prior art evaluates the position of the color coordinates of the desired color in the color space. More specifically, it is evaluated in which sub-triangle that can be produced in the color space by the four light sources the reference color is placed.
  • the color diagram of Fig. 6 shows an example with five possible sub- triangles delimited by the points PO to P5. Then the respectively fourth light source outside of the sub- triangle containing the reference color point Px is switched off, which results in three light sources being easily controlled in view of a tri-stimulus input signal.
  • a first aspect relates to a method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value
  • the method comprises the step of determining the drive value for each LED by multiplying the nominal color coordinate value with the pseudo-inverse of a gain matrix representing, in color coordinates, the light output of each LED for a given drive value.
  • Another aspect proposes a method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the method comprising the steps of:
  • the method may furthermore comprise the step of
  • the generated drive signals may be pulse-width modulated signals .
  • the method may furthermore comprise the step of calculating and storing for the superimposed light of the at least four LEDs critical areas of the color space, wherein the pseudo-matrix multiplication would result in a drive value of less than zero for at least one LED.
  • the pseudo-matrix multiplication step may be carried out only if said coordinate values are comprised in none of the calculated critical areas.
  • the method may comprise the step of measuring the gain matrix.
  • the measurement may be carried out in a start-up sequence while any feed-back loop is deactivated.
  • the invention also relates to a computer software program product, performing a method according to any of the preceding steps when run on a computing device such as e.g. a microprocessor.
  • the invention furthermore relates to an integrated circuit, such as e.g. an ASIC, which is designed to carry out a method a set forth above.
  • an integrated circuit such as e.g. an ASIC, which is designed to carry out a method a set forth above.
  • Another aspect relates to a system for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value.
  • the system comprises means for determining the drive value for each LED by multiplying the nominal color coordinate value with a pseudo- inverse of a gain matrix, the gain matrix representing, in color coordinates, the light output of each LED for a given drive value.
  • the invention also proposes a system for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the system comprising:
  • the invention proposes a decoupling method by using the pseudo-inverse of the gain matrix.
  • each of the four differing spectra preferably R, G, B, and any additional color
  • each of the four differing spectra can be considered independently from each other as the respective contributions from one color to the other color are taking into account by a compensation factor which is given by the pseudo-inverse matrix.
  • the four colors are switched on, without feedback loop and control, and via the color sensors the influence of the respectively four colors on the X, Y, Z coordinates are measured.
  • the pseudo- inverse matrix is set up in the startup sequence.
  • a PWM control is carried out .
  • the invention also comprises an additional aspect in which beforehand critical areas in the CIE coordinate system are calculated.
  • Critical areas are those areas where the pseudo-inverse matrix based control asks for contribution of a color of zero or even a negative value, which is physically impossible. If a reference color coordinate now is in one of these critical areas, the controller reduces the corresponding one of the at least for different colors to zero and then carries out the control using the remaining three using a 3x3 matrix mapping.
  • This aspect reflects the problem that using the complete pseudo-matrix approach for the decoupling, in these critical areas either an instability of the control can occur or it takes longer iteration steps for the controller to reach the target color coordinate, as the controller has to overcome the physical constraint that a color can only be reduced to zero but no negative value - theoretically computed using the method - can be achieved.
  • the CIE diagram will show a big portion in which, using the decoupling method, all four light sources or colors are active. At the border areas there will be the critical areas where one of the light sources or colors has to be switched off. Instead of the decoupling pseudo-inverse matrix, the simple three to three mapping will be carried out in order to calculate the control values for the remaining three other LEDs or colors. Actually, as in each of the critical areas one of the four light sources has to be completely switched off, a total of four ⁇ alternative matrices' has to be computed. Actually, these alternative matrices are simply the complete decoupling matrix, in which one row corresponding to the color to be set to zero is entirely set to zero.
  • Fig. 1 shows a light control system according to a first embodiment of the present invention
  • Fig. 2 describes a method according to the invention
  • Fig. 3 shows a second embodiment of the present invention
  • Fig. 4 shows a color space diagram in accordance with the invention
  • Fig. 5 shows a further color space diagram in accordance with the invention.
  • Fig. 6 shows a color space diagram according to the prior art.
  • Fig. 1 shows a control system 1 according to the invention and adapted to control a plurality of LEDs so as to generate a given light or light color.
  • a control system 1 adapted to control a plurality of LEDs so as to generate a given light or light color.
  • four LEDs having different spectra can be controlled.
  • the four LEDs may consist in a red, a green and a blue LED together with an additional LED that may e.g. be a white LED.
  • the plurality of LEDs is advantageously assembled together in an illumination device .
  • the control system 1 is designed to map a nominal color coordinate to drive signals for the different LEDs.
  • the control system 1 is designed to control (drive) the at least four different light sources such that the superposition of the at least four spectra results in light having a preset nominal color coordinate with values Xref, Yref, Zref describing a desired color in the so- called CIE 1931 XYZ color space or CIE 1931 color space that has been created by the Commission Internationale d'Eclairage (CIE) in 1931.
  • CIE Commission Internationale d'Eclairage
  • the tristimulus values can also be defined and given in an alternative three-component additive color model like in the CIE xyY, the CIE L*u*v* or the CIE L*a*b* color space.
  • the reference coordinate values Xref, Yref, Zref of the desired color to be generated by the control system 1 can be stored in a memory or buffer 2 designed to store the color coordinates in the used color space which is here the CIE 1931 color space.
  • the memory 2 is connected to a controller 3 that comprise e.g. a Pi-controller 4 and a pseudo-inverse multiplier 5.
  • the Pi-controller or proportional-integral controller 4 is advantageously a diagonal Pi-controller that is configured to output coordinate values cX, cY, cZ on the basis of the reference coordinate values Xref, Yref, Zref and actually measured color coordinates of the superimposed light emitted by the different LEDs, which measured color coordinates are fed back to the control system.
  • Alternatively other known controllers can replace said PI- controller 4.
  • the controller 3 is able to provide adapted control signals for driving the LEDs in order to achieve a desired color by mixing the LEDs outputs.
  • the control signals can be control voltages or control currents for the LEDs.
  • controller 3 defines the duty-cycles of pulse- width modulation (PWM) signals used to drive the LEDs.
  • PWM pulse- width modulation
  • the PWM control is preferably carried out in order to avoid problems caused by the intensity-dependence of the spectrum of an LED.
  • the output of the Pi-controller 4 is fed to the pseudo- inverse multiplier 5 that multiplies the coordinate values cX, cY, cZ with a matrix M "1 being the pseudo-inverse or generalized inverse of a matrix M representing the influence of the respective four colors generated by the four LEDs on the X, Y, Z coordinates.
  • the calculated values R, G, B, A can be used for generating the PWM signals used to drive the LEDs.
  • Said values R, G, B, A correspond to respective driving signals PWM R , PWM G , PWM B , PWM A for controlling the individual LEDs.
  • an additional LED driver module (not shown) can be integrated in the system 1 to generate appropriate driving signals PWM R , PWM G , PWM B , PWM A for the RGBA LEDs on the basis of the calculated values R, G, B, A.
  • the plant 6 comprises a multiplier 7 that multiplies the obtained R, G, B, A matrix with said M matrix, also called the gain matrix, in order to obtain the coordinate values X, Y, Z of the light generated by the four LEDs.
  • Fig. 2 illustrates a startup sequence that is necessary in order to calculate the values of the pseudo-inverse matrix M "1 used in the controller 3.
  • the first step Sl of the startup sequence is therefore to measure the influence of the spectrum generated by the red LED on the colors generated by the other green, blue and white LEDs. Likewise the respective influence of the spectrum generated by the green, blue and white LEDs on the other LEDs is measured.
  • the four colors are switched on, without feedback loop and control.
  • the influence of the respectively four colors on the X, Y, Z (e.g. RGB) coordinates are measured via color sensors (not shown) .
  • the gain matrix M comprises the influence factors measured in the first step Sl.
  • the measurement step Sl can be carried out at different moments.
  • the measurement will take place during or after production of the LEDs and/or during production of said illumination device comprising the LEDs.
  • the gain matrix M can be measured in a testing routine at startup or during the lifetime of the LEDs to take account of the possible modification of the spectrum generated by each LED. Most advantageously this measurement is carried out periodically during the lifetime of the LEDs.
  • the pseudo- inverse matrix M '1 is calculated S2. This calculation is performed for example according to a known mathematical method, such that the following equation is verified:
  • the above described embodiment can be generalized to a decoupling method using a pseudo-inverse control for controlling a number of n LEDs, which method can be defined by the equation:
  • M is the gain matrix and PWM_LEDi is the PWM signal for driving the i th LED of the illumination system, the value of the PWM_LEDi signal being comprised between 0 and 1.
  • control actions can preferably be the PWM duty-cycles for each LED, i.e. for each channel, wherein the minimum possible value for such a control action is zero.
  • the second embodiment now comprises an additional step of calculating S4 said critical areas in the CIE 1931 color space in order to avoid such time-consuming tracking.
  • Fig. 3 shows a control system 1' according to the second embodiment of the invention and adapted to control the output of four LEDs to generate a desired mixed light/color.
  • a memory 2' is adapted to store the color coordinates rx, ry, rY of the desired color according to the CIE xyY color space.
  • the memory 2' is coupled to a first xyY to XYZ transformation module 10 for converting color coordinate values from the xyY to the XYZ color space so as to obtain new values Xref, Yref, Zref describing the desired or reference color.
  • the output of said first transformation module 10 is connected to a feedback adder 11 that generates an error signal by subtracting coordinate values X, Y, Z generated by the control system 1' , from the reference coordinate values Xref, Yref, Zref.
  • a Pi-controller 4 similar to that of the first embodiment then outputs the values ⁇ X, ⁇ Y, ⁇ Z.
  • the color coordinates rx, ry, rY defining the desired color are also fed to a sectoring module 12 that has to verify whether or not the reference point defined by the coordinates rx, ry, rY is located within a critical area of the color space.
  • This module 12 also performs the calculation S4 of said critical areas and preferably stores the result.
  • a control unit 13 is connected to the output of the PI- controller 4 and to the output of the sectoring module 12.
  • the control unit 13 receives from the sectoring module 12 information about the location of the desired color within the color space and whether the desired color is located in a critical area of the color space. More specifically the information received by the control unit 13 can define that all four LEDs or that only three LEDs shall be activated.
  • the desired color is outside a critical area of the color space and the control unit 13 causes the pseudo-inverse multiplier 5 to multiply the coordinate values ⁇ X, ⁇ Y, ⁇ Z with the pseudo-inverse matrix M x of the first embodiment.
  • the obtained RGBA coordinates are as follows:
  • the control unit 13 causes a multiplier 14 to multiply the coordinates ⁇ X, ⁇ Y, ⁇ Z with a modified pseudo-inverse matrix that has no contribution for the LED to be switched off.
  • the system 1' also comprise the multiplier 7 of the first embodiment that multiplies the obtained R, G, B, A coordinates with the gain matrix M to obtain the values X, Y, Z that are sent to the feedback adder 11.
  • the values X, Y, Z correspond to the actual colors produced by the LED module and are detected by a photosensor (not shown) .
  • the system 1' further comprise a second XYZ to xyY transformation module 15 for converting the values X, Y, Z into the xyY color space.
  • the critical areas where respectively the red (R) , green (G) , blue (B) or additional (A) LED is turned-off, can be defined by following equations:
  • the X and Z coordinates can be replaced by the CIE xyY coordinates as follows:
  • Figs. 5 and 6 depict a given color gamut in a xyz color space diagram.
  • the hatched area 50 corresponds to the critical area of the color space wherein the green LED is turned off according to the present invention.
  • the corresponding area of the color space wherein the green LED is switched off according to the above mentioned prior art WO 2006/109237 Al is the hatched area 60 of Fig. 6.
  • the transitions between the different areas of the color space are also smoother.
  • Another advantage is that, upon applying the method of the invention, the LEDs are turned off only when necessary.
  • the inventive controller 3, 5 can further store information about temperature and correct the driving of the LEDs accordingly.
  • the computing the pseudo-inverse may be performed externally to the LED driving system.
  • a calibration sequence can be done during or after production.
  • a computer which is not part of the system itself and which may be connected only for the calibration procedure, can control the system and define the light output levels for the LEDs.
  • the system can then set up a gain matrix representing, in color coordinates, the light output of each LED for the given drive values.
  • the (external) personal computer can compute the pseudo- inverse of the gain matrix, and could also compute the drive values for each LED by multiplying the nominal color coordinate value with the pseudo-matrix.
  • the computed results can then be stored in the system, for example in the controller 3 or the memory 2.
  • the computing can be done partly in the personal computer, but it can be also done partly or completely within the system itself. While performing parts of the computing outside of the system, the demand on the controller 3 capabilities may be reduced.

Landscapes

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

Abstract

The present invention generally relates to the generation of a light color by mixing a plurality of light emitting diodes (LEDs). More particularly, the invention is directed to the generation of a desired color and to the control of LEDs in order to obtain the desired color by mixing the light produced by the respective LEDs. It is proposed a method for controlling a plurality of at least four light emitting diodes or LEDs for generating a desired light or color, comprising applying (5) a pseudo- inverse matrix (M-1) to the coordinate values (Xref, Yref, Zref) of the desired light, said coordinate values (Xref, Yref, Zref) being expressed in a color space, wherein the pseudo-inverse matrix (M-1) is the pseudo-inverse of a gain matrix (M) reflecting the influence of each LED on said color space.

Description

System and method for controlling LEDs
The present invention generally relates to the generation of a light color by mixing a plurality of light emitting diodes (LEDs). More particularly, the invention is directed to the generation of a desired color and to the control of LEDs in order to obtain the desired color by mixing the light produced by the respective LEDs.
Prior art US 6552495 Bl discloses a control system for generating a desired light color on the basis of three red, green and blue LEDs. The system comprises a sensor for- measuring the color coordinates of the light color generated by the three LEDs. A transformation module is adapted to convert said color coordinates to another color space. Reference color coordinates corresponding to the desired light and expressed in the second color space are provided by a further transformation module. Error color coordinates between the desired light color coordinates and the generated light color coordinates are then generated and fed to a driver module configured to generate drive signals IR, IG, IB for driving the LEDs.
However using only three LEDs to produce a color on the basis of only three basic colors (RGB) is disadvantageous since the color rendering index (CRI) of the mixed color is limited in view of the spectral gaps between the red, green and blue colors. Prior art WO 2006/109237 Al proposes to solve this problem and to increase the CRI of the generated color by using an LED module comprising more that three different LEDs. By adding a fourth LED, for example a white LED, the CRI index can be improved.
However the problem is now that the reference value of the desired color has only three coordinates X, Y, Z, while four output signals have to be produced to drive the three LEDs and the additional one. To overcome this problem said prior art evaluates the position of the color coordinates of the desired color in the color space. More specifically, it is evaluated in which sub-triangle that can be produced in the color space by the four light sources the reference color is placed. The color diagram of Fig. 6 shows an example with five possible sub- triangles delimited by the points PO to P5. Then the respectively fourth light source outside of the sub- triangle containing the reference color point Px is switched off, which results in three light sources being easily controlled in view of a tri-stimulus input signal.
In this respect it is an object of the present invention to improve the control of a light module having at least four different light sources with differing spectra.
A first aspect relates to a method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value The method comprises the step of determining the drive value for each LED by multiplying the nominal color coordinate value with the pseudo-inverse of a gain matrix representing, in color coordinates, the light output of each LED for a given drive value.
Another aspect proposes a method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the method comprising the steps of:
- setting up a gain matrix representing, in color coordinates, the light output of each LED for a given drive value,
- computing the pseudo-inverse of the gain matrix, and
- computing the drive value for each LED by multiplying the nominal color coordinate value wit the pseudo-inverse of the gain matrix.
The method may furthermore comprise the step of
- measuring the color coordinate of the light produced by the at least four LEDs, and - computing the drive value for each LED by multiplying a value which is a function of the nominal color coordinate value and the actually measured value with the pseudo- inverse of the gain matrix.
The generated drive signals may be pulse-width modulated signals .
The method may furthermore comprise the step of calculating and storing for the superimposed light of the at least four LEDs critical areas of the color space, wherein the pseudo-matrix multiplication would result in a drive value of less than zero for at least one LED. The pseudo-matrix multiplication step may be carried out only if said coordinate values are comprised in none of the calculated critical areas.
Any LED for which the pseudo-inverse multiplication would result in a negative control value can be switched off.
The method may comprise the step of measuring the gain matrix.
The measurement may be carried out in a start-up sequence while any feed-back loop is deactivated.
The invention also relates to a computer software program product, performing a method according to any of the preceding steps when run on a computing device such as e.g. a microprocessor.
The invention furthermore relates to an integrated circuit, such as e.g. an ASIC, which is designed to carry out a method a set forth above.
Another aspect relates to a system for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value. The system comprises means for determining the drive value for each LED by multiplying the nominal color coordinate value with a pseudo- inverse of a gain matrix, the gain matrix representing, in color coordinates, the light output of each LED for a given drive value. Finally, the invention also proposes a system for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the system comprising:
- means for storing a gain matrix representing, in color coordinates, the light output of each LED for a given drive value, - means for computing the pseudo-inverse of the gain matrix, and
- means for computing the drive value for each LED by multiplying the nominal color coordinate value with the pseudo-matrix .
The invention proposes a decoupling method by using the pseudo-inverse of the gain matrix. Using the decoupling method, each of the four differing spectra (preferably R, G, B, and any additional color) can be considered independently from each other as the respective contributions from one color to the other color are taking into account by a compensation factor which is given by the pseudo-inverse matrix.
When using the invention, whenever possible, all four (or more) colors will usually make some contribution, contrary to the prior art. However, it can not be excluded that in "extreme" color coordinate situations (i.e. when the desired nominal color coordinate to be produced is in the outer regions of the color coordinates) , one light source or color has to be switched off. This occurs nevertheless less frequently in comparison to the prior art case. In order to calculate the values of the pseudo-inverse matrix, a startup sequence may be necessary, e.g. at the manufacturing side or periodically in use, in order to measure the gain matrix. Via this startup sequence, the gain matrix can be measured and then be stored in the controller (or the pseudo-inverse thereof is stored). E.g. by sequentially switching on the different LEDs, it can be measured how much a certain color spectrum influences the respectively other colors.
In the startup sequence the four colors are switched on, without feedback loop and control, and via the color sensors the influence of the respectively four colors on the X, Y, Z coordinates are measured. Thus, the pseudo- inverse matrix is set up in the startup sequence. In order to avoid problems caused by the intensity-dependants of the spectrum of a LED, preferably a PWM control is carried out .
The invention also comprises an additional aspect in which beforehand critical areas in the CIE coordinate system are calculated. Critical areas are those areas where the pseudo-inverse matrix based control asks for contribution of a color of zero or even a negative value, which is physically impossible. If a reference color coordinate now is in one of these critical areas, the controller reduces the corresponding one of the at least for different colors to zero and then carries out the control using the remaining three using a 3x3 matrix mapping. This aspect reflects the problem that using the complete pseudo-matrix approach for the decoupling, in these critical areas either an instability of the control can occur or it takes longer iteration steps for the controller to reach the target color coordinate, as the controller has to overcome the physical constraint that a color can only be reduced to zero but no negative value - theoretically computed using the method - can be achieved.
Using this critical area approach, the CIE diagram will show a big portion in which, using the decoupling method, all four light sources or colors are active. At the border areas there will be the critical areas where one of the light sources or colors has to be switched off. Instead of the decoupling pseudo-inverse matrix, the simple three to three mapping will be carried out in order to calculate the control values for the remaining three other LEDs or colors. Actually, as in each of the critical areas one of the four light sources has to be completely switched off, a total of four ^alternative matrices' has to be computed. Actually, these alternative matrices are simply the complete decoupling matrix, in which one row corresponding to the color to be set to zero is entirely set to zero.
The foregoing form as well as other forms, features and advantages of the invention will become further apparent from the following detailed description of the embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims.
Fig. 1 shows a light control system according to a first embodiment of the present invention,
Fig. 2 describes a method according to the invention Fig. 3 shows a second embodiment of the present invention,
Fig. 4 shows a color space diagram in accordance with the invention,
Fig. 5 shows a further color space diagram in accordance with the invention, and
Fig. 6 shows a color space diagram according to the prior art.
With reference to Fig. 1 a first embodiment of the present invention will be described in the followings.
Fig. 1 shows a control system 1 according to the invention and adapted to control a plurality of LEDs so as to generate a given light or light color. In the particular embodiment of Fig. 1, four LEDs having different spectra can be controlled. E.g. the four LEDs may consist in a red, a green and a blue LED together with an additional LED that may e.g. be a white LED. The plurality of LEDs is advantageously assembled together in an illumination device .
The control system 1 is designed to map a nominal color coordinate to drive signals for the different LEDs.
The control system 1 is designed to control (drive) the at least four different light sources such that the superposition of the at least four spectra results in light having a preset nominal color coordinate with values Xref, Yref, Zref describing a desired color in the so- called CIE 1931 XYZ color space or CIE 1931 color space that has been created by the Commission Internationale d'Eclairage (CIE) in 1931. Such combined values X, Y and Z are also referred to as the tristimulus values of a color and reflect the amounts of the three primary colors in the CIE 1931 color space. Even if the present embodiment bases on said color space, the tristimulus values can also be defined and given in an alternative three-component additive color model like in the CIE xyY, the CIE L*u*v* or the CIE L*a*b* color space.
The reference coordinate values Xref, Yref, Zref of the desired color to be generated by the control system 1 can be stored in a memory or buffer 2 designed to store the color coordinates in the used color space which is here the CIE 1931 color space.
The memory 2 is connected to a controller 3 that comprise e.g. a Pi-controller 4 and a pseudo-inverse multiplier 5. The Pi-controller or proportional-integral controller 4 is advantageously a diagonal Pi-controller that is configured to output coordinate values cX, cY, cZ on the basis of the reference coordinate values Xref, Yref, Zref and actually measured color coordinates of the superimposed light emitted by the different LEDs, which measured color coordinates are fed back to the control system. Alternatively other known controllers can replace said PI- controller 4.
The controller 3 is able to provide adapted control signals for driving the LEDs in order to achieve a desired color by mixing the LEDs outputs. The control signals can be control voltages or control currents for the LEDs. Preferably controller 3 defines the duty-cycles of pulse- width modulation (PWM) signals used to drive the LEDs. The PWM control is preferably carried out in order to avoid problems caused by the intensity-dependence of the spectrum of an LED.
The output of the Pi-controller 4 is fed to the pseudo- inverse multiplier 5 that multiplies the coordinate values cX, cY, cZ with a matrix M"1 being the pseudo-inverse or generalized inverse of a matrix M representing the influence of the respective four colors generated by the four LEDs on the X, Y, Z coordinates.
The pseudo-inverse multiplier 5 and therefore also the controller 3 of the system 1 output R, G, B, A values according to the following equation:
with the matrix M A-I having the dimension 4*3.
The calculated values R, G, B, A can be used for generating the PWM signals used to drive the LEDs. Said values R, G, B, A correspond to respective driving signals PWMR, PWMG, PWMB, PWMA for controlling the individual LEDs. Advantageously an additional LED driver module (not shown) can be integrated in the system 1 to generate appropriate driving signals PWMR, PWMG, PWMB, PWMA for the RGBA LEDs on the basis of the calculated values R, G, B, A.
Applying this pseudo-inverse matrix M 1 at the output of the Pi-controller 4 will result in a decoupled system. In that way, each of the red, green, blue and additional colors can be considered independently from each other as the respective contribution from one color to the other color is taken into account by a compensation factor which is given by the pseudo-inverse matrix M'1.
The plant 6 comprises a multiplier 7 that multiplies the obtained R, G, B, A matrix with said M matrix, also called the gain matrix, in order to obtain the coordinate values X, Y, Z of the light generated by the four LEDs.
Fig. 2 illustrates a startup sequence that is necessary in order to calculate the values of the pseudo-inverse matrix M"1 used in the controller 3.
Within this startup sequence, it has to be measured Sl how much a certain color spectrum influences the respectively other colors. In the case of an RGBW system making use of red, green, blue and white LEDs, the first step Sl of the startup sequence is therefore to measure the influence of the spectrum generated by the red LED on the colors generated by the other green, blue and white LEDs. Likewise the respective influence of the spectrum generated by the green, blue and white LEDs on the other LEDs is measured.
In the first step Sl of the startup sequence the four colors are switched on, without feedback loop and control. The influence of the respectively four colors on the X, Y, Z (e.g. RGB) coordinates are measured via color sensors (not shown) .
The result of those measures is put in the gain matrix M. This means that said gain matrix M comprises the influence factors measured in the first step Sl. The measurement step Sl can be carried out at different moments. Advantageously the measurement will take place during or after production of the LEDs and/or during production of said illumination device comprising the LEDs. After this manufacturing step, the gain matrix M can be measured in a testing routine at startup or during the lifetime of the LEDs to take account of the possible modification of the spectrum generated by each LED. Most advantageously this measurement is carried out periodically during the lifetime of the LEDs.
Once the gain matrix M has been measured, the pseudo- inverse matrix M'1 is calculated S2. This calculation is performed for example according to a known mathematical method, such that the following equation is verified:
1 0 0
M ■ M'l = 0 1 0
0 0 1
The equations to be fulfilled by the pseudo-inverse matrix
M"1 are : MM~lM =M
M~λMM~λ =M~λ
As a result the output of the plant 6 corresponds to the coordinate values modified by the Pi-controller 4:
Once the matrix M"1 has been calculated, it is stored S3 in the controller 3.
The above described embodiment can be generalized to a decoupling method using a pseudo-inverse control for controlling a number of n LEDs, which method can be defined by the equation:
wherein M is the gain matrix and PWM_LEDi is the PWM signal for driving the ith LED of the illumination system, the value of the PWM_LEDi signal being comprised between 0 and 1. In the followings a second embodiment of the present invention will be described.
The use of the pseudo-inverse controller 3 of the first embodiment can result in control actions that are smaller than zero. As previously described the control actions can preferably be the PWM duty-cycles for each LED, i.e. for each channel, wherein the minimum possible value for such a control action is zero.
In other words they are areas of the CIE 1931 color space, which may be called critical areas, where the pseudo- inverse matrix M"1 based control according to the first embodiment asks for a color contribution of zero or below zero. Such a negative contribution is in fact physically impossible and results in a time-consuming tracking of a reference point located in such a critical area.
The second embodiment now comprises an additional step of calculating S4 said critical areas in the CIE 1931 color space in order to avoid such time-consuming tracking.
Fig. 3 shows a control system 1' according to the second embodiment of the invention and adapted to control the output of four LEDs to generate a desired mixed light/color.
A memory 2' is adapted to store the color coordinates rx, ry, rY of the desired color according to the CIE xyY color space. The memory 2' is coupled to a first xyY to XYZ transformation module 10 for converting color coordinate values from the xyY to the XYZ color space so as to obtain new values Xref, Yref, Zref describing the desired or reference color.
The output of said first transformation module 10 is connected to a feedback adder 11 that generates an error signal by subtracting coordinate values X, Y, Z generated by the control system 1' , from the reference coordinate values Xref, Yref, Zref. A Pi-controller 4 similar to that of the first embodiment then outputs the values ΔX, ΔY, ΔZ.
The color coordinates rx, ry, rY defining the desired color are also fed to a sectoring module 12 that has to verify whether or not the reference point defined by the coordinates rx, ry, rY is located within a critical area of the color space. This module 12 also performs the calculation S4 of said critical areas and preferably stores the result.
A control unit 13 is connected to the output of the PI- controller 4 and to the output of the sectoring module 12. The control unit 13 receives from the sectoring module 12 information about the location of the desired color within the color space and whether the desired color is located in a critical area of the color space. More specifically the information received by the control unit 13 can define that all four LEDs or that only three LEDs shall be activated.
In case the four LEDs are to be used, the desired color is outside a critical area of the color space and the control unit 13 causes the pseudo-inverse multiplier 5 to multiply the coordinate values ΔX, ΔY, ΔZ with the pseudo-inverse matrix M x of the first embodiment. The obtained RGBA coordinates are as follows:
K X vRτ> K YR K ZR
G K. X vGn K. YG K ZG Y B K. X vBτ> K. YB K ZB
K XVAA K YA K ZA Input
Output M -1
In case one of the LEDs has to be switched off because the desired color is in a critical area, the control unit 13 causes a multiplier 14 to multiply the coordinates ΔX, ΔY, ΔZ with a modified pseudo-inverse matrix that has no contribution for the LED to be switched off. For example the corresponding modified pseudo-inverse matrix for switching off the red LED would be MR=O -1:
The system 1' also comprise the multiplier 7 of the first embodiment that multiplies the obtained R, G, B, A coordinates with the gain matrix M to obtain the values X, Y, Z that are sent to the feedback adder 11. The values X, Y, Z correspond to the actual colors produced by the LED module and are detected by a photosensor (not shown) . The system 1' further comprise a second XYZ to xyY transformation module 15 for converting the values X, Y, Z into the xyY color space.
In the followings the step of calculating S4 said critical areas in the CIE 1931 color space, which can be performed by the sectoring module 12, will be described.
The critical areas, where respectively the red (R) , green (G) , blue (B) or additional (A) LED is turned-off, can be defined by following equations:
R = KxR ■ X + KγR ■ Y + K2R Z = O B = KxB ■ X + KYB ■ Y + KZB Z = O A = KxA ■ X + h'γA ■ Y + KZA Z = O
For calculating the critical area in which the red LED is turned off, following equation has to be considered:
R = KxR ■ X + KYR ■ Y + KZR -Z = O
The X and Z coordinates can be replaced by the CIE xyY coordinates as follows:
x
X = - Z = ±- .Y y y
KxR ■ - ■ Y + KYR ■ Y + KZR ■ LJLJL .γ = 0 y y
By solving this equation one obtains: KXR • - + KYR + KzR AZR ■ - - KzR = 0
.'/ y LI
{KXR - KzR) ■ - + KzR ■ - = KZR - KYR U U
(KxR - K∑R) ■ J-" + KZR = y ■ (K'ZR - KYR)
KXR - K'ZR , K'ZR
U = x
KZR - KYR ' K'ZR - KYR
This equation defines the critical area with the red LED turned off, which is shown under reference A4 in Fig. 4. Similar reasoning applies to the other critical areas.
The advantages of the present invention over the prior art can be seen on Figs. 5 and 6 that depict a given color gamut in a xyz color space diagram. The hatched area 50 corresponds to the critical area of the color space wherein the green LED is turned off according to the present invention.
The corresponding area of the color space wherein the green LED is switched off according to the above mentioned prior art WO 2006/109237 Al is the hatched area 60 of Fig. 6.
The fact that the hatched area 50, 60 is smaller in the diagram of the invention shows that the overall CRI values obtained with a system of the invention is better than the CRI according to the prior art.
The transitions between the different areas of the color space are also smoother.
Another advantage is that, upon applying the method of the invention, the LEDs are turned off only when necessary. The inventive controller 3, 5 can further store information about temperature and correct the driving of the LEDs accordingly.
The computing the pseudo-inverse may be performed externally to the LED driving system. For example, a calibration sequence can be done during or after production. A computer, which is not part of the system itself and which may be connected only for the calibration procedure, can control the system and define the light output levels for the LEDs. The system can then set up a gain matrix representing, in color coordinates, the light output of each LED for the given drive values. Then the (external) personal computer can compute the pseudo- inverse of the gain matrix, and could also compute the drive values for each LED by multiplying the nominal color coordinate value with the pseudo-matrix. The computed results can then be stored in the system, for example in the controller 3 or the memory 2. The computing can be done partly in the personal computer, but it can be also done partly or completely within the system itself. While performing parts of the computing outside of the system, the demand on the controller 3 capabilities may be reduced.

Claims

TridonicAtco Schweiz AGClaims
1. A method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the method comprising the step of determining the drive value for each LED by multiplying the nominal color coordinate value with the pseudo-inverse of a gain matrix representing, in color coordinates, the light output of each LED for a given drive value.
2. A method for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the method comprising the steps of:
- setting up a gain matrix representing, in color coordinates, the light output of each LED for a given drive value,
- computing the pseudo-inverse of the gain matrix, and
- computing the drive value for each LED by multiplying the nominal color coordinate value with the pseudo- inverse matrix.
3. The method according to claim 1 or 2, comprising the step of
- measuring the color coordinate of the light produced by the at least four LEDs, and - computing the drive value for each LED by multiplying a value which is a function of the nominal color coordinate value and the actually measured value with the pseudo-matrix.
4. A method according to any of the preceding claims, wherein the generated drive signals (PWMR, PWMG, PWMB, PWMA) are pulse-width modulation signals.
5. A method according to claim 3 or 4, comprising calculating (S4) for the superimposed light of the at least four LEDs critical areas of the color space, wherein the pseudo-matrix multiplication would result in a drive value of less than zero for at least one LED.
6. A method according to claim 5, wherein the pseudo-matrix multiplication step is carried out only if said coordinate values are comprised in none of the calculated critical areas.
7. A method according to claim 5 or 6, wherein any LED for which the pseudo-inverse multiplication would result in a negative control value is switched off.
8. A method according to anyone of the preceding claims, comprising the step of measuring (Sl) the gain matrix (M) .
9. The method according to claim 8, wherein the measurement is carried out in a start-up sequence while any feed-back loop is deactivated.
10. A computer software program product, performing a method according to any of the preceding steps when run on a computing device such as e.g. a microprocessor .
11. An integrated circuit, such as e.g. an ASIC, which is designed to carry out a method according to any of claims 1 to 9.
12. A system for driving a plurality of at least four LEDs with differing spectra such that the superposition of the light emitted by the at least four LEDs results in light of a pre-set nominal color coordinate value, the system comprising means for determining the drive value for each LED by multiplying the nominal color coordinate value with a pseudo- inverse of a gain matrix, the gain matrix representing, in color coordinates, the light output of each LED for a given drive value.
13. The system according to claim 12, comprising
- color sensors for measuring the color coordinate of the light produced by the at least four LEDs, and - means for computing the drive value for each LED by multiplying a value which is a function of the nominal color coordinate value and the actually measured value with the pseudo-matrix.
14. The system according to claim 12 or 13, comprising a PWM drive unit, supplied wit the drive values and performing a PWM driving of the LEDs, wherein the duty cycle of the PWM drive depends on the supplied drive values.
15. The system according to any of claims 12 to 14, comprising means for storing for the superimposed light of the at least four LEDs critical areas of the color space, wherein the pseudo-matrix multiplication would result in a drive value of less than zero for at least one LED.
16. The system according to claim 15, which is designed to perform the pseudo-matrix multiplication step is carried out only if said coordinate values are comprised in none of the calculated critical areas.
17. The system according to claim 15 or 16, wherein any LED for which the pseudo-inverse multiplication would result in a negative control value is switched off.
18. The system according to anyone of claims 12 to 17, comprising means for measuring (Sl) the gain matrix (M) .
19. The system according to claim 16, designed for carrying out the measurement of the gain matrix in a start-up sequence while any feed-back loop is deactivated.
20. The system according to anyone of claims 12 to 19, where at least a part of the computing is performed externally of the system itself.
EP09726563A 2008-03-31 2009-03-30 System and method for controlling leds Not-in-force EP2258146B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102008016756A DE102008016756A1 (en) 2008-03-31 2008-03-31 Arrangement and method for controlling LEDs
PCT/EP2009/002296 WO2009121539A1 (en) 2008-03-31 2009-03-30 System and method for controlling leds

Publications (2)

Publication Number Publication Date
EP2258146A1 true EP2258146A1 (en) 2010-12-08
EP2258146B1 EP2258146B1 (en) 2012-05-23

Family

ID=40887379

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09726563A Not-in-force EP2258146B1 (en) 2008-03-31 2009-03-30 System and method for controlling leds

Country Status (3)

Country Link
EP (1) EP2258146B1 (en)
DE (1) DE102008016756A1 (en)
WO (1) WO2009121539A1 (en)

Families Citing this family (38)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8841864B2 (en) 2011-12-05 2014-09-23 Biological Illumination, Llc Tunable LED lamp for producing biologically-adjusted light
US8547391B2 (en) * 2011-05-15 2013-10-01 Lighting Science Group Corporation High efficacy lighting signal converter and associated methods
US9024536B2 (en) 2011-12-05 2015-05-05 Biological Illumination, Llc Tunable LED lamp for producing biologically-adjusted light and associated methods
US9532423B2 (en) 2010-07-23 2016-12-27 Lighting Science Group Corporation System and methods for operating a lighting device
US9827439B2 (en) 2010-07-23 2017-11-28 Biological Illumination, Llc System for dynamically adjusting circadian rhythm responsive to scheduled events and associated methods
US8760370B2 (en) 2011-05-15 2014-06-24 Lighting Science Group Corporation System for generating non-homogenous light and associated methods
US8686641B2 (en) 2011-12-05 2014-04-01 Biological Illumination, Llc Tunable LED lamp for producing biologically-adjusted light
US8743023B2 (en) 2010-07-23 2014-06-03 Biological Illumination, Llc System for generating non-homogenous biologically-adjusted light and associated methods
US9681522B2 (en) 2012-05-06 2017-06-13 Lighting Science Group Corporation Adaptive light system and associated methods
US8401231B2 (en) 2010-11-09 2013-03-19 Biological Illumination, Llc Sustainable outdoor lighting system for use in environmentally photo-sensitive area
US8729832B2 (en) 2011-05-15 2014-05-20 Lighting Science Group Corporation Programmable luminaire system
US8901850B2 (en) 2012-05-06 2014-12-02 Lighting Science Group Corporation Adaptive anti-glare light system and associated methods
US9173269B2 (en) 2011-05-15 2015-10-27 Lighting Science Group Corporation Lighting system for accentuating regions of a layer and associated methods
US8754832B2 (en) 2011-05-15 2014-06-17 Lighting Science Group Corporation Lighting system for accenting regions of a layer and associated methods
US8847436B2 (en) 2011-09-12 2014-09-30 Lighting Science Group Corporation System for inductively powering an electrical device and associated methods
US9913341B2 (en) 2011-12-05 2018-03-06 Biological Illumination, Llc LED lamp for producing biologically-adjusted light including a cyan LED
US8866414B2 (en) 2011-12-05 2014-10-21 Biological Illumination, Llc Tunable LED lamp for producing biologically-adjusted light
US8963450B2 (en) 2011-12-05 2015-02-24 Biological Illumination, Llc Adaptable biologically-adjusted indirect lighting device and associated methods
US9220202B2 (en) 2011-12-05 2015-12-29 Biological Illumination, Llc Lighting system to control the circadian rhythm of agricultural products and associated methods
US9289574B2 (en) 2011-12-05 2016-03-22 Biological Illumination, Llc Three-channel tuned LED lamp for producing biologically-adjusted light
DE102012003018B4 (en) 2012-02-15 2016-08-11 Diehl Aerospace Gmbh Method for producing light of a desired light color by means of light-emitting diodes
US9366409B2 (en) 2012-05-06 2016-06-14 Lighting Science Group Corporation Tunable lighting apparatus
US9402294B2 (en) 2012-05-08 2016-07-26 Lighting Science Group Corporation Self-calibrating multi-directional security luminaire and associated methods
US9006987B2 (en) 2012-05-07 2015-04-14 Lighting Science Group, Inc. Wall-mountable luminaire and associated systems and methods
US8680457B2 (en) 2012-05-07 2014-03-25 Lighting Science Group Corporation Motion detection system and associated methods having at least one LED of second set of LEDs to vary its voltage
DE102012209252A1 (en) * 2012-05-31 2013-12-05 Hella Kgaa Hueck & Co. Method for calibrating illumination device for illuminating e.g. interior arrangement elements in motor car, involves generating drive signal from output value to control respective light source of illumination device
US9174067B2 (en) 2012-10-15 2015-11-03 Biological Illumination, Llc System for treating light treatable conditions and associated methods
DE102013201915A1 (en) 2012-10-31 2014-05-15 Tridonic Jennersdorf Gmbh Method and arrangement for controlling LEDs
US9347655B2 (en) 2013-03-11 2016-05-24 Lighting Science Group Corporation Rotatable lighting device
US9353935B2 (en) 2013-03-11 2016-05-31 Lighting Science Group, Corporation Rotatable lighting device
US9018854B2 (en) 2013-03-14 2015-04-28 Biological Illumination, Llc Lighting system with reduced physioneural compression and associate methods
US9151453B2 (en) 2013-03-15 2015-10-06 Lighting Science Group Corporation Magnetically-mountable lighting device and associated systems and methods
US9222653B2 (en) 2013-03-15 2015-12-29 Lighting Science Group Corporation Concave low profile luminaire with magnetic lighting devices and associated systems and methods
US20140268731A1 (en) 2013-03-15 2014-09-18 Lighting Science Group Corpporation Low bay lighting system and associated methods
US9157618B2 (en) 2013-03-15 2015-10-13 Lighting Science Group Corporation Trough luminaire with magnetic lighting devices and associated systems and methods
DE102013010512B4 (en) 2013-06-22 2015-05-28 Diehl Aerospace Gmbh Arrangement with at least one metameric lighting device and passenger cabin
CN107454718B (en) * 2017-08-31 2023-11-28 广州光联电子科技有限公司 An LED light source and optical system with color temperature correction function
WO2023164759A1 (en) * 2022-03-01 2023-09-07 Mimosa Diagnostics Inc. Releasable portable imaging device for multispectral moblie tissue assessment

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0760223A1 (en) * 1995-08-31 1997-03-05 Hewlett-Packard GmbH Apparatus for monitoring, in particular pulse oximeter
US6205244B1 (en) * 1998-06-23 2001-03-20 Intel Corporation Method for imager device color calibration utilizing light-emitting diodes or other spectral light sources
DE10040620B4 (en) * 1999-08-21 2006-08-10 Maryniak, André, Dr.-Ing. Method for controlling or regulating a unit to be controlled
US6507159B2 (en) * 2001-03-29 2003-01-14 Koninklijke Philips Electronics N.V. Controlling method and system for RGB based LED luminary
US6552495B1 (en) 2001-12-19 2003-04-22 Koninklijke Philips Electronics N.V. Adaptive control system and method with spatial uniform color metric for RGB LED based white light illumination
CN100566484C (en) 2005-04-14 2009-12-02 皇家飞利浦电子股份有限公司 Color control of white LED lights
US7315139B1 (en) * 2006-11-30 2008-01-01 Avago Technologis Ecbu Ip (Singapore) Pte Ltd Light source having more than three LEDs in which the color points are maintained using a three channel color sensor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2009121539A1 *

Also Published As

Publication number Publication date
EP2258146B1 (en) 2012-05-23
DE102008016756A1 (en) 2009-10-01
WO2009121539A1 (en) 2009-10-08

Similar Documents

Publication Publication Date Title
WO2009121539A1 (en) System and method for controlling leds
US8593481B2 (en) Method and arrangement for setting a color locus, and luminous system
TWI427580B (en) Led luminary system and method for controlling an led luminary
JP4992423B2 (en) Backlight unit driving apparatus and driving method thereof
CN103854599B (en) For the method and apparatus controlling organic light-emitting diode (OLED) display apparatus electric current
EP2672787B1 (en) Lighting apparatus and method for controlling the same
JP5346592B2 (en) Light emitting device and light emitting device driving method
CN102150474B (en) Tunable color solid state light emitting
US6507159B2 (en) Controlling method and system for RGB based LED luminary
CN101467490A (en) Led backlight for LCD with color uniformity recalibration over lifetime
US8382287B2 (en) Method and apparatus for calibrating a color temperature of a projector
JP2010514131A (en) Lighting device having multiple primary colors
US8737731B2 (en) Method and apparatus for correcting light
EP3583465B1 (en) Laser driver
US20090078852A1 (en) Chrominance compensation method and panel lightening method in a display apparatus
WO2008139369A1 (en) Lighting device with a plurality of light emitters
US9723678B2 (en) Methods of controlling RGBW lamps, RGBW lamps and controller therefor
CN101409045B (en) Chromaticity Compensation Method and Illumination Method of Display Device
CN103270367A (en) Method of controling an illumination device having a number of light source arrays
CN104838726A (en) Scrolling Interrupt Adjustable Color LED Illumination Source
US20130191056A1 (en) Method of determining pwm values for led modules
JP6124551B2 (en) Light emitting device and control method thereof
US20230262855A1 (en) Illuminant device for emitting light of a continuously adjustable colour, in particular for individualizing and/or illuminating an interior space
KR20160099402A (en) Lighting apparatus controlling light flux and method for controlling same
KR101779429B1 (en) Lighting apparatus controlling light flux ratio and method for controlling same

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

17P Request for examination filed

Effective date: 20100915

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 HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL BA RS

RIN1 Information on inventor provided before grant (corrected)

Inventor name: BETSCHART, ADRIAN

Inventor name: PEREIRA, EDUARDO

Inventor name: ZIMMERMANN, MICHAEL

Inventor name: SCHENKER, YVES

17Q First examination report despatched

Effective date: 20110606

DAX Request for extension of the european patent (deleted)
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

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 559603

Country of ref document: AT

Kind code of ref document: T

Effective date: 20120615

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 602009007224

Country of ref document: DE

Effective date: 20120719

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20120523

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

Effective date: 20120523

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120923

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120823

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120824

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120924

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

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

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120903

26N No opposition filed

Effective date: 20130226

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 602009007224

Country of ref document: DE

Effective date: 20130226

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120823

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130330

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130331

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: AT

Payment date: 20150326

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20120523

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20130330

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20090330

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 8

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20160331

Year of fee payment: 8

REG Reference to a national code

Ref country code: AT

Ref legal event code: MM01

Ref document number: 559603

Country of ref document: AT

Kind code of ref document: T

Effective date: 20160330

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160330

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20170330

Year of fee payment: 9

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20171130

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: 20170331

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20180330

REG Reference to a national code

Ref country code: DE

Ref legal event code: R084

Ref document number: 602009007224

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20180330

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20190528

Year of fee payment: 11

REG Reference to a national code

Ref country code: DE

Ref legal event code: R079

Ref document number: 602009007224

Country of ref document: DE

Free format text: PREVIOUS MAIN CLASS: H05B0033080000

Ipc: H05B0045000000

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 602009007224

Country of ref document: DE

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: 20201001