DE102017111087B4 - Process for the optical function monitoring of the light emission of at least three LED lamps in luminaires - Google Patents

Abstract

Method for carrying out a test for light emission for a first illuminant of a lamp for lighting or display purposes with the first illuminant and at least one further second illuminant and a further third illuminant, - wherein the first illuminant and the second illuminant and the third illuminant each have an on - can adopt a state in which they each emit light with a lamp-specific first light output, and can each assume an off-state in which they each emit light with a lamp-specific second light output and - with reference to each lamp these three lamps for the amount of the first light output of this lamp is greater than the amount of the second light output of this lamp with the steps - Bring the first lamp in its on state; - Bring the second lamp in its off state; - Bring the third lamp in its off state; - irradiating the second lamp with the light of the first lamp and- irradiating the third lamp with the light of the first lamp; - measuring a first electrical parameter of the second lamp to determine a first measured value for this first parameter; - measuring a second electrical parameter of the third illuminant to determine a second measured value for this second parameter; - comparison of the first measured value with a first threshold value; - comparison of the second measured value with a second threshold value; - evaluation of the first illuminant as faulty if the comparison of the first The measured value with the first threshold value shows that the first light output of the first illuminant is too low and when the comparison of the second measured value with the second threshold value shows that the first light output of the first illuminant is too low.

Description

Generic term

The proposed method is based on a test for light emission for a first illuminant of a lamp for lighting or display purposes with two or more illuminants, in particular LEDs.

General introduction

The use of light emitting diodes (LEDs) as light sources for safety-related tasks in vehicles is becoming more and more important. Vehicles with autonomous or semi-autonomous states in particular require LED diagnostics for optical status displays (e.g. LED light strips). At least the states “LED is lit” or “LED is not lit” should be able to be recognized in order to be able to recognize failed LEDs. From the prior art, only methods for indirect diagnosis are known which evaluate the voltage drop across the LEDs or the current or energy consumption of the LEDs. Intelligent drivers are used for this, although the diagnosis in interaction with a driver is only carried out indirectly via a voltage / current evaluation.

State of the art

For example from the scriptures DE 10 2015 008 110 A1 , DE 10 2015 008 109 A1 , DE 10 2016 105 516 B3 , DE 10 2016 105 517 B3 , DE 10 2016 119 584 A1 , US 2008/0 204 029 A1 , US 2007/0 159 750 A1 , EP 0 955 619 A1 , DE 10 2011 120 781 A1 , DE 11 2009 005 227 T5 , DE 10 2014 107 947 A1 , US 2012/0 200 296 A1 and US 2006/0 170 287 A1 disclose methods and devices for monitoring the electrical or thermal parameters of light emitting diodes and light emitting diode chains.

From the DE 102 27 487 A1 discloses a lighting device for backlighting a display device for text / graphic information with LEDs as lighting means. In the disclosure of the DE 102 27 487 A1 these lighting means are used as sensors for the ambient brightness in order to track the brightness of the display. For this purpose, individual LEDs are not energized and instead are used as sensors for this ambient brightness within the relevant control loop when they are not lit.

The main disadvantage of the prior art is that the actual function of the light output of the illuminants is not checked.

task

The proposal is therefore based on the object of creating a solution which does not have the above disadvantages of the prior art and has further advantages.

This object is achieved by a method according to claim 1.

Solution of the task

With RGB lighting, several LED spotlights are arranged as RGB lamps in a housing. This combination of several LEDs as lighting means to form an overall device is referred to below as a lighting means group consisting of several lighting means. Within such a group of lamps, the light emission of a single LED the lamp group of a first color if it is another LED the first color of the illuminant group is irradiated as a photo current or photo voltage at this neighboring, not activated LED the illuminant group can be detected.

The emission of light this LED the group of lamps thus generates at the neighboring one LED the illuminant group generates a photocurrent, which in turn leads to an LED voltage on the irradiated LED the lamp group leads. This LED voltage is called photo voltage in the following. The product of photo current and photo voltage corresponds to that in the irradiated LED light energy converted into electrical energy. This energy is preferably measured with an external impressed voltage of 0V as a pure photo current or with an externally impressed current of 0A as pure photo voltage. The person skilled in the art can also determine the energy generated at other operating points, this determination then being more complex. Photo current and photo voltage can be used as measures for the on the irradiated LED Light output can be used.

Since in automotive applications the control processors that control the lighting groups are equipped with an analog-to-digital converter in order to be able to record various parameters of the lighting device, these analog-to-digital converters of the control processors can be used, for example, via a multiplexer to the photovoltage or the photocurrent or, more generally, that caused by the irradiation in the irradiated LED to measure the energy generated by the lighting group and to determine a measured value. Since it is known what intensity of the radiating LED should be transmitted, the measured value determined in this way can be compared with a threshold value. The emitted intensity is preferably only switched between on and off distinguished. If the measured value is below the threshold value, either the emitting one sends LED too little light output or the irradiated LED generates too little photo voltage or photo current. In this respect, it can already be assumed that the group of illuminants as such has at least one of these defects.

A group of lamps in the sense of this furnace arrangement is usually more than one LED include. Typically, but not necessarily, a group of illuminants for applying the proposed method comprises a red, a green and a blue LED or similar combinations of complementary colors. In that case, in the event of a single fault, it can then be found out by cyclically swapping the radiating and the irradiated LEDs of such a group of illuminants LED is actually flawed. This enables a direct diagnosis of the LED light emission in the case of groups of lamps made up of LEDs. In contrast to this, in the prior art, only the position of the electrical operating parameters is evaluated within specified tolerance ranges. It is not checked whether the lamps actually emit light. The proposed method therefore enables the light emission to be checked directly instead of an indirect conclusion as to such light emission. Different groups of lamps of a larger lighting device can also shine one below the other. The method proposed here is therefore also suitable for testing luminous strips with suitable luminous means that are arranged along the luminous strip. Preferably, the lighting means on the light strip are then immediately rejected. With the same lighting means, with linear, planar laying, the same optical couplings should then occur between the individual lighting means, which thus enables the proposed method to be used in this case. If the luminous means are not equally spaced along such a luminous strip, the use of the proposed method requires a previously known distance or a previously known optical coupling between the luminous means. Depending on the design, this prior knowledge can be determined on a prototype in the form of suitable coupling parameters. Similar coupling factors with certain tolerances are then to be expected with structurally identical light strips. Appropriate prior knowledge can also be obtained to a certain extent by simulating or calculating the mutual irradiation intensity. If the light band is not to be laid in a planar manner, this has the same effect as different distances between the light sources of the light band. The proposed method is also suitable for testing luminous mats, that is to say two-dimensional arrangements of lighting means. In this case, the lighting means are preferably arranged in the form of a two-dimensional grid. A cubic or hexagonal arrangement of the illuminants with respect to one another is particularly preferred. In the event of deviations from such regular structures, prior knowledge can also be obtained through simulation or experiments with prototypes that provide the necessary parameters for calculating the optical coupling.

An objection typically raised by those skilled in the art is that the groups of illuminants generally have LEDs of different colors in order to be able to represent all colors recognizable by humans in the color space as RGB colors. Therefore, according to this opinion, it should certainly be possible with a shorter wave LED , for example a blue one LED , in a longer wave LED , for example a red one LED to cause a photocurrent, since the band gap of the long-wave LED , for example the red one LED , is smaller than the photon energy of the short-wave LED , so the blue one LED , emitted photons. Conversely, however, according to this expert opinion, experts expect that it is simply not possible with a longer wave LED , for example a red one LED , in a shorter wave LED , for example a blue one LED to produce a reliably measurable photo current or a reliably measurable photo voltage, since the band gap of the short-wave LED , for example the blue one LED , greater than the photon energy of the long wave LED , for example the red one LED , emitted photons.

However, this fact does not stand in the way of a diagnosis, since sufficient status detection is possible via reciprocal combinations.

Tests have shown that if there is a defect in the emission, there is also no measurable effect (photocurrent / voltage) in the absorption. This can be derived theoretically from Einstein's law that the emission coefficient is always the same as the absorption coefficient.

• - Schritt 1: Die blaue LED soll blaues Licht abstrahlen. Die rote LED und die grüne LED werden bevorzugt nicht bestromt.
• - Schritt 2: Es wird ein erster Messwert für die Fotospannung und/oder den Fotostrom der roten LED ermittelt. Ggf. kann beispielsweise über das Produkt aus Fotospannung und Fotostrom die Fotoleistung der roten LED ermittelt werden.
• - Schritt 3: Es wird ein zweiter Messwert für die Fotospannung und/oder den Fotostrom der grünen LED ermittelt. Ggf. kann beispielsweise über das Produkt aus Fotospannung und Fotostrom die Fotoleistung der grünen LED ermittelt werden.
• - Schritt 4: Der erste Messwert wird mit einem Schwellwert für den ersten Messwert bei Bestrahlung der roten LED durch die blauen LED verglichen und ein erster Vergleichswert ermittelt.
• - Schritt 5: Der zweite Messwert wird mit einem Schwellwert für den zweiten Messwert bei Bestrahlung der grünen LED durch die blauen LED verglichen und ein zweiter Vergleichswert ermittelt.
• - Der erste Vergleichswert nimmt dabei einen ersten Zustand an, wenn der erste Messwert unterhalb des Schwellwerts für den ersten Messwert bei Bestrahlung der roten LED durch die blauen LED liegt, und einen zweiten Zustand an, wenn der erste Messwert oberhalb des Schwellwerts für den ersten Messwert bei Bestrahlung der roten LED durch die blauen LED liegt. Der erste Zustand entspricht also dem Fall, dass die blaue LED strahlt und die rote LED das Licht der blauen LED empfängt und in einen Fotostrom bzw. eine Fotospannung umwandelt. Der zweite Zustand entspricht dann dem Fall, dass zumindest einer dieser beiden Vorgänge nicht stattfindet.
• - Der zweite Vergleichswert nimmt dabei einen ersten Zustand an, wenn der zweite Messwert unterhalb des Schwellwerts für den zweiten Messwert bei Bestrahlung der grünen LED durch die blauen LED liegt, und einen zweiten Zustand an, wenn der zweite Messwert oberhalb des Schwellwerts für den zweiten Messwert bei Bestrahlung der grünen LED durch die blauen LED liegt. Der erste Zustand entspricht also dem Fall, dass die blaue LED strahlt und die grüne LED das Licht der blauen LED empfängt und in einen Fotostrom bzw. eine Fotospannung umwandelt. Der zweite Zustand entspricht dann dem Fall, dass zumindest einer dieser beiden Vorgänge nicht stattfindet.
• - Schritt 6: Es folgt das Ermitteln des Zustands der LEDs aus dem ermittelten ersten Vergleichswert und dem ermittelten zweiten Vergleichswert.
• - Ist der erste Vergleichswert im zweiten Zustand und der zweite Vergleichswert im zweiten Zustand, so strahlt die blaue LED und das Licht der blauen LED wird von der roten LED empfangen und von der grünen LED empfangen. Dies lässt darauf schließen, dass die blaue LED korrekt arbeitet und dass die grüne LED korrekt arbeitet und dass die rote LED korrekt arbeitet.
• - Ist der erste Vergleichswert im zweiten Zustand und der zweite Vergleichswert im ersten Zustand, so strahlt die blaue LED und das Licht der blauen LED wird von der roten LED empfangen und von der grünen LED nicht empfangen. Dies lässt darauf schließen, dass die blaue LED korrekt arbeitet und dass die grüne LED nicht korrekt arbeitet und dass die rote LED korrekt arbeitet.
• - Ist der erste Vergleichswert im ersten Zustand und der zweite Vergleichswert im zweiten Zustand, so strahlt die blaue LED und das Licht der blauen LED wird von der roten LED nicht empfangen und von der grünen LED empfangen. Dies lässt darauf schließen, dass die blaue LED korrekt arbeitet und dass die grüne LED korrekt arbeitet und dass die rote LED nicht korrekt arbeitet.
• - Ist der erste Vergleichswert im ersten Zustand und der zweite Vergleichswert im ersten Zustand, so strahlt die blaue LED wahrscheinlich nicht und das Licht der blauen LED wird von der roten LED nicht empfangen und von der grünen LED nicht empfangen. Dies lässt darauf schließen, dass entweder als erste Möglichkeit die blaue LED nicht korrekt arbeitet oder dass als zweite Möglichkeit die grüne LED und die rote LED nicht korrekt arbeiten.

The procedure for measuring RGB lamp groups with a blue one LED which is designed to emit blue light and a green one LED which is designed to emit green light and a red light LED , which is intended to emit red light, can now look like this:

• - Step 1: the blue one LED should emit blue light. The Red LED and the green one LED are preferably not energized.
• - Step 2: There is a first measured value for the photo voltage and / or the photo current of the red LED determined. Possibly. can for example about the product of photo voltage and photo current is the photo output of the red LED be determined.
• - step 3 : There is a second measured value for the photo voltage and / or the photo current of the green LED determined. Possibly. For example, the photographic power of the green can be determined via the product of photo voltage and photo current LED be determined.
• - Step 4: The first measured value is with a threshold value for the first measured value with irradiation of the red LED through the blue LED compared and determined a first comparison value.
• - Step 5: The second measured value is set with a threshold value for the second measured value when irradiated with the green LED through the blue LED compared and determined a second comparison value.
• The first comparison value assumes a first state when the first measured value is below the threshold value for the first measured value when the red one is irradiated LED through the blue LED and a second state when the first measured value is above the threshold value for the first measured value when the red LED through the blue LED lies. The first state corresponds to the case that the blue LED shines and the red LED the light of the blue LED receives and converts it into a photo current or photo voltage. The second state then corresponds to the case that at least one of these two processes does not take place.
• The second comparison value assumes a first state if the second measured value is below the threshold value for the second measured value when the green one is irradiated LED through the blue LED is, and a second state when the second measured value is above the threshold value for the second measured value when the green LED through the blue LED lies. The first state corresponds to the case that the blue LED shines and the green LED the light of the blue LED receives and converts it into a photo current or photo voltage. The second state then corresponds to the case that at least one of these two processes does not take place.
• Step 6: The status of the LEDs is then determined from the first comparison value determined and the second comparison value determined.
• - If the first comparison value is in the second state and the second comparison value is in the second state, the blue one shines LED and the light of the blue LED is from the red LED received and from the green LED receive. This suggests that the blue LED works correctly and that the green LED works correctly and that the red LED works correctly.
• - If the first comparison value is in the second state and the second comparison value is in the first state, the blue one shines LED and the light of the blue LED is from the red LED received and from the green LED not received. This suggests that the blue LED works correctly and that the green LED not working correctly and that the red one LED works correctly.
• - If the first comparison value is in the first state and the second comparison value is in the second state, the blue one shines LED and the light of the blue LED is from the red LED not received and from the green LED receive. This suggests that the blue LED works correctly and that the green LED works correctly and that the red LED not working properly.
• - If the first comparison value is in the first state and the second comparison value is in the first state, the blue one shines LED probably not and the light of the blue LED is from the red LED not received and from the green LED not received. This suggests that either the first option is the blue LED not working correctly or that the green one as a second possibility LED and the red one LED not working correctly.

This measurement can be done with the green LED as a transmitter and the red one LED as the only receptions can also be carried out in an analogous manner in order to obtain further information. Of course, more colors and / or LEDs can also be used.

On the other hand, a clear diagnosis with assignment of the exact error to a specific light source (here LEDs) is often not required in real applications. As a rule, a statement about a defect in the lighting group is sufficient in itself.

1. a) Innerhalb einer Leuchtmittelgruppe durch Absorption zwischen benachbarten LEDs dieser Leuchtmittelgruppe oder
2. b) Leuchtmittelgruppen übergreifend, wobei die Lichtemission einer LED einer ersten Leuchtmittelgruppe mittels einer LED einer benachbarten Leuchtmittelgruppe detektiert werden kann.

It is now proposed that the light detection for diagnosis can be carried out as follows:

1. a) Within a lamp group by absorption between neighboring LEDs of this lamp group or
2. b) across lighting groups, with the light emission one LED a first group of lamps by means of a LED an adjacent group of lamps can be detected.

For example, method b) can be carried out within an LED chain along an LED strip can be used. Since the distances are then larger, the signals are then smaller. A diagnosis of all LEDs of all lamp groups is possible in the context of a diagnosis cycle or by sensible coding of the control, possibly even during operation.

It is therefore suggested that the photocurrent of a LED to be measured at times when it is not activated, i.e. is in an off state and therefore does not emit any light itself. Furthermore, at this point in time at least one other LED are in the on state, i.e. emit light. This light must be in sufficient quantity on the LED can fall in the off state and its level is suitable for it LED to radiate in the off state in such a way that a measurable photo current or a measurable photo voltage results. However, only that can then be assessed LED in the off state, since there are several LEDs in the LED could radiate in the off state.

It is therefore also proposed to measure the photocurrent of several LEDs temporally parallel or quasi parallel to those times in which they are not activated and are therefore in an off state and thus do not emit any light themselves. Furthermore, another must be at this point LED are in the on state, i.e. emit light. A sufficient quantity of this light must fall on the LEDs in the off state and its level must be suitable for shining into the LEDs in the off state in such a way that a measurable photo current is produced. The rating is then preferred LED in the on state.

The proposed method thus serves to carry out a test for light emission for a first illuminant, preferably for a first one LED , a luminaire intended for lighting or display purposes. The lamp has at least one first light source - the said first LED - and at least one further second lamp - a second LED . The first light source - the first LED -and the second bulb - the second LED - can each assume an on state in which they emit light with a lamp-specific first light output, and each assume an off state in which they emit light with a lamp-specific second light output. This means that a first light output can be assigned to the first light source and a first light output can be assigned to the second light source and that the first light output of the first light source can be different from the first light output of the second light source. This also means that a second light output can be assigned to the first light source and a second light output can be assigned to the second light source and that the second light output of the first light source can be different from the second light output of the second light source. In the following of this disclosure, cases with more than two illuminants are also considered, where the same applies. The amount of the first light output is greater than the amount of the second light output. The second light output is preferably zero or almost zero, which means that in the off state the relevant lighting means preferably does not light up. The first light source, so preferably the first LED , is switched on in the proposed method and thus brought into the on state. The second lamp is switched off, i.e. switched off. The first illuminant is preferred, that is, the first is preferred LED So to the second illuminant, so preferably the second LED , arranged that the first illuminant then irradiates the second illuminant with its light. The aforementioned analog-to-digital converter is then used to measure an electrical parameter of the second luminous means, that is to say preferably the second LED , to determine a measured value for this parameter. In the case of a second LED as a second illuminant, this electrical parameter is preferably a photo voltage of the second LED that this generated as a result of the irradiation, or a photocurrent of the second LED that this generates as a result of irradiation. It is therefore important that the value of the selected parameter depends on the lighting in the form of the light power radiated into the second illuminant and that the second illuminant is brought into a state in which this dependency can be measured. The second is therefore particularly preferred LED switched off in order to achieve a good signal-to-noise ratio. The measured value recorded in this way - typically by the said analog-to-digital converter - is then compared with a threshold value. This is usually done by the program of the control computer or a computer to which the control computer sends the measured value or a value derived therefrom. This evaluates the first and / or second illuminant or the lamp as "possibly faulty" if the comparison of the measured value with the threshold value shows that the first light output of the first illuminant is too low or that the value of the parameter of the second illuminant is insufficient . In the case of two LEDs, this means that the comparison of the measured value with the threshold value shows that the photo voltage or the photo current that the second LED generated is too low. This insufficient photo current or this insufficient photo voltage is then either due to an insufficient first light output of the first illuminant, that is to say the first LED , and thus too little irradiation of light power into the second light source, i.e. the second LED , due to or due to insufficient sensitivity of the second illuminant, i.e. the second LED compared to the radiation from the first illuminant, i.e. through the first LED . In this last case, too, a defect can typically result in the second LED can be assumed. In order to be able to make the necessary distinction, the procedure can be extended to three light sources. Since most lamp groups have three lamps of different colors, this extension can typically be used for lamps with adjustable colors. To test a first light source, a first test is then carried out using the method described immediately above with the first and second light sources and a second test with the first and third light sources. The third lamp is also switched off and measured, that is, treated like the second lamp according to the method described above. A first test result for the first test and a second test result for the second test are thus obtained. These two test results can each have the values “OK” or “possible defect” of one of the two lamps involved in the respective test. The first test result can therefore have the values “OK” or “possible defect” for the first lamp, for example the first LED , and for the second light source, for example the second LED , to have. The second test result can therefore have the values “OK” or “possible defect” for the first light source, for example the first LED , and for the third lamp, for example the third LED , to have.

If both tests result in "OK", the first lamp is OK.

If the first test results in “OK” and the second test “possible defect”, then there is probably a defect in the third light source, i.e. the third in the case of LEDs LED , in front.

If the first test results in “possible defect” and the second test “OK”, then there is probably a defect in the second light source, i.e. the second in the case of LEDs LED , in front.

If the first test results in “possible defect” and the second test “possible defect”, then there is a defect in the first light source, i.e. the first in the case of LEDs LED , in front.

These tests preferably do not run sequentially one after the other, but more or less in parallel. For better clarity we now assume that the third light source is switched on and the first and second light source are used as a sensor for the light from the third light source. Compared to the description immediately preceding, this is a renaming in order to improve the clarity of the description. The first light source was tested in the description above. The third light source is now checked by simply renaming it. However, this does not change anything in terms of technical content. The method then provides that the third light source, i.e. the third LED , is switched on and is thus brought into the ON state, while the first and second lighting means, i.e. preferably the first and second LED , switched off, i.e. brought into the off state. The arrangement of the first, second and third illuminant to one another should now be such that the third illuminant can illuminate the first and second illuminant. In addition, such irradiation should produce a measurable effect in the first and second lighting means. In the case of LEDs, this is the generation of a photo current or photo voltage in the first and second LED . If the third light source is located, preferably the third one LED , in the on state, it then irradiates the first and second light sources, i.e. the first and second LED , and causes the said effect there, which in the case of LEDs causes the generation of said photovoltage or said photocurrent in the first and second LED means. In order to be able to detect the effect generated in the first and second illuminant, a first parameter of the first illuminant in the form of a first measured value and a second parameter of the second illuminant in the form of a second measured value is now preferably determined by means of the analog-to-digital converter of the control processor detected, which are modified by the irradiation with the light of the first illuminant. In the case of LEDs, the first parameter is the first measured value of a first photovoltage or a first photocurrent that passes through the first LED when irradiated with light the third LED are generated, and the second parameter the second measured value of a second photo voltage or a second photo current, which is generated by the second LED when irradiated with light the third LED be generated.

The first measured value is preferably compared with a first threshold value by the control processor. The second measured value is preferably compared with a second threshold value by the control processor.

The control processor preferably evaluates the third illuminant as defective if the comparison of the first measured value with the first threshold value and the second measured value with the second threshold value shows that the first light output of the third illuminant is too low.

In the case of a first LED the photocurrent or the photovoltage is the first as the first light source LED to determine a first lighting value, preferably measured by the analog-to-digital converter of the control processor.

In the case of a second LED The second light source is the photo current or the photo voltage of the second LED to determine a second lighting value, preferably measured by the analog-to-digital converter of the control processor.

The third LED then illuminate the first in this example LED and the second LED , both of which are in the off state during the measurement.

This is followed by the comparison of the first lighting value with a first threshold value and the comparison of the second lighting value with a second threshold value. This comparison is preferably carried out again with the aid of the control processor or a computer to which the control processor has transmitted the first and second lighting values or values derived therefrom.

This evaluates the third LED that are the first and second LED illuminated as faulty if the amount of the first lighting value is smaller than the first threshold value and if the amount of the second lighting value is smaller than the second threshold value.

This evaluates the second LED going through the third LED is illuminated, as faulty when the amount of the first lighting value is greater than the first threshold value and when the amount of the second lighting value is smaller than the second threshold value.

This evaluates the first LED going through the third LED is illuminated as faulty if the amount of the first lighting value is less than the first threshold value and if the amount of the second lighting value is greater than the second threshold value.

This evaluates the third LED that are the first and second LED illuminated as probably error-free when the amount of the first lighting value is greater than the first threshold value and when the amount of the second lighting value is greater than the second threshold value.

Not all of these evaluations are mandatory. However, it is suggested that all of these assessments be carried out preferentially.

The proposed methods are particularly suitable for testing so-called RGB light modules. Such RGB light modules are preferably combinations of three LEDs of different colors. Preferably has a first LED one blue color, another LED a green color and a third LED a red color. It is known that with biodynamic light it is common to use a fourth color that is not consciously recognizable by the human eye with the same intensity, which controls the release of melatonin in the human body and thus influences the sleep / wake rhythm. In this respect, more than three colors or focus wavelengths are also conceivable. The combination with infrared LEDs as a transmitter for communication purposes is also conceivable. There are therefore also light modules with more than four LED - Centroid wavelengths conceivable.

The 1 schematically shows such an exemplary one LED Module with a first LED LED1 and a second LED LED2 and a third LED LED3 .

2 shows an example and schematically an apparatus for carrying out the proposed method. The first LED LED1 of LED Module 1 is from a first power source S1 with a first stream I1 provided. The second LED LED2 of LED Module 1 is from a second power source S2 with a second stream I2 provided. The third LED LED3 of the LED module 1 is from a third power source S3 with a third stream I3 provided. An analog-to-digital converter ( ADC ) can be connected to the output nodes of the first power source via an analog multiplexer (MUX), which is controlled by a computer system (µC) S1 ) or the second power source ( S2 ) or the third power source ( S3 ) can be switched. Typically this configuration is also used to measure the voltage drop across the first LED LED1 or the second LED LED2 or the third LED LED3 monitor and detect failures in operation. The power sources ( S1 , S2 , S3 ) are controlled by the computer system (µC) via a control bus or control signal lines (SB). With the power sources shown here as an example ( S1 , S2 , S3 ) In real implementations, it is likely to be what are known as high-side power sources that draw their energy from the positive supply voltage. Such high-side current sources are preferably implemented with the aid of a current mirror, the MOS diode for generating the reference voltage and the current source transistor preferably being connected directly to this positive supply voltage. This preferred implementation is in the 2 but not shown. Instead, ideal power source symbols are drawn in that refer to the reference potential ( GND ) are related, i.e. are more theoretical in nature. The analog-to-digital converter ( ADC ) reports the measured values to the computer system (µC). The computer system (µC) carries out the proposed method.

The measurement of the first is particularly preferred LED LED1 in that the computer system (µC) is the first LED LED1 by switching on the first power source S1 with a non-zero electrical first current I1 and the second power source S2 and the third power source S3 turns off. Using the multiplexer (MUX) and the analog-to-digital converter ( ADC ) the computer system (µC) then preferably determines the second photo voltage of the second LED LED2 and the third photo voltage of the third LED LED3 . The second photo voltage of the second LED LED2 is the potential difference between the output node of the second current source S2 and the reference potential GND . The third photo voltage of the third LED LED3 is the potential difference between the output node of the third current source S3 and the reference potential GND .

The measurement of the second is particularly preferred LED LED2 in that the computer system (µC) has the second LED LED2 by switching on the second power source S2 with a non-zero electrical second current I2 and the first power source S1 and the third power source S3 turns off. Using the multiplexer (MUX) and the analog-to-digital converter (ADC), the computer system (μC) then preferably determines the first photo voltage of the first LED LED1 the third photo voltage and the third LED LED3 . The first photo tension of the first LED LED1 is the potential difference between the output node of the first current source S1 and the reference potential GND . The third photo voltage of the third LED LED3 is the potential difference between the output node of the third current source S3 and the reference potential GND .

The measurement of the third is particularly preferred LED LED3 in that the computer system (µC) is the third LED LED3 by switching on the third power source S3 with a non-zero electrical third current I3 and the second power source S2 and the first power source S1 turns off. Using the multiplexer (MUX) and the analog-to-digital converter (ADC), the computer system (μC) then preferably determines the second photo voltage of the second LED LED2 the first photo voltage and the first LED LED1 . The second photo voltage of the second LED LED2 is the potential difference between the output node of the second current source S2 and the reference potential GND . The first photo tension of the first LED LED1 is the potential difference between the output node of the first current source S1 and the reference potential GND .

The first photo voltage determined in this way and the second photo voltage and the third photo voltage are preferably compared by the computer system (μC) after each of these two three measurements with an associated threshold value. The associated threshold values are preferably stored in the program or data memory of the computer system (μC). As is easy to see, the redundancy of measurements can be used to reduce the number of measurements and to save time. If the computer system detects an error, it signals an error to a higher-level unit, for example a bus master or a control device, for example via a signaling line or a data bus.

Advantage of the proposal

Such a diagnostic method makes it possible, at least in some implementations, to test illuminants if they are measurably influenced by irradiation with light in at least one operating state. The advantages are not limited to this.

In contrast to the currently used diagnoses, which only provide indirect information about the LED current and voltage and thus do not allow a clear conclusion to an actual emission of light, the proposal presented here enables a clear conclusion to an actual emission of light by a Illuminant or a LED .

List of reference symbols

ADC

Analog-to-digital converter;

I1

first current of the first current source ( S1 ) to supply the first LED ( LED1 ) with electrical energy;

I2

second current of the second current source ( S2 ) to supply the second LED ( LED2 ) with electrical energy .;

I3

third current of third current source ( S3 ) to supply the third LED ( LED3 ) with electrical energy;

GND

Reference potential;

LED

light-emitting diode or light-emitting diode. The light-emitting diodes here generally stand for light sources that can generate a photo current and / or photo voltage when irradiated;

LED1

first LED

LED2

second LED ;

LED3

third LED ;

MUX

Multiplexer;

S1

first power source to supply the first LED LED1 with the first current (I1). The first power source is controlled by the computer system (µC) via the control bus (SB);

S2

first power source for supplying the second LED LED2 with the second current (I2). The second power source is controlled by the computer system (µC) via the control bus (SB);

S3

first power source to supply the third LED LED3 with the third current (I3). The third power source is controlled by the computer system (µC) via the control bus (SB);

SLS

Signal line for signaling or transmitting the data provided;

glossary

LED

At a LED in the sense of this disclosure it is a light-emitting diode. Such light-emitting diodes can have different focal wavelengths. Insofar as the claims speak of LEDs, this also includes such lighting means that allow the proposed method to be used in the same way.

Centroid wavelength

The center of gravity wavelength results in the sense of this disclosure as an intensity maximum in the wavelength spectrum of the relevant LED or the relevant light source.

List of scriptures cited

• DE 10 2015 008 110 A1 ,
• DE 10 2015 008 109 A1 ,
• DE 10 2016 105 516 B3,
• DE 10 2016 105 517 B3,
• DE 10 2016 119 584 A1
• US 2008/0 204 029 A1
• US 2007/0 159 750 A1
• DE 10 2016 105 516 B3 ,
• EP 0 955 619 A1 ,
• DE 10 2011 120 781 A1 ,
• DE 11 2009 005 227 T5 ,
• DE 10 2014 107 947 A1 ,
• US 2012/0 200 296 A1
• US 2006/0 170 287 A1
• US 2007/0 159 750 A1

Claims (4)

Method for carrying out a test for light emission for a first illuminant of a lamp for lighting or display purposes with the first illuminant and at least one further second illuminant and one further third illuminant, - whereby the first illuminant and the second illuminant and the third illuminant can each assume an on state, in which they each emit light with a first light output specific to the illuminant, and can each assume an off state in which they each emit light with a Light source emit specific second light output and - In relation to each lamp of these three lamps, the amount of the first light output of this lamp is greater than the amount of the second light output of this lamp with the steps Bringing the first illuminant into its on state; Bringing the second illuminant into its off state; Bringing the third illuminant into its off state; - irradiating the second illuminant with the light of the first illuminant and - irradiating the third illuminant with the light of the first illuminant; - Measuring a first electrical parameter of the second illuminant to determine a first measured value for this first parameter; - Measuring a second electrical parameter of the third illuminant to determine a second measured value for this second parameter; - Comparison of the first measured value with a first threshold value; - Comparison of the second measured value with a second threshold value; Evaluation of the first light source as defective if the comparison of the first measured value with the first threshold value shows that the first light output of the first light source is too low and if the comparison of the second measured value with the second threshold value shows that the first light output of the first light source is too low. Method for performing a test for light emission for a third LED of a lamp for lighting or display purposes with the third LED and at least one further first LED and one further second LED, wherein the first LED and the second LED and the third LED can each assume an on state in which they emit light with a first light output specific to the respective LED, and can each assume an off state in which they each also emit light emit a second light output specific for the respective LED and - with the amount of the first light output of this LED being greater than the amount of the second light output of this LED with the steps - bringing the first LED into its output Status; Bringing the second LED to its off-state; Bringing the third LED to its on state; Irradiating the first LED with the light of the third LED and irradiating the second LED with the light of the third LED; - Measuring the photo current or photo voltage of the first LED to determine a first lighting value; - Measuring the photo current or photo voltage of the second LED to determine a second lighting value; - Comparison of the first lighting value with a first threshold value; - Comparison of the second lighting value with a second threshold value; Evaluation of the third LED as faulty, • if the amount of the first lighting value is less than the first threshold value and • if the amount of the second lighting value is less than the second threshold value. Method for performing a test for a second LED of a lamp for lighting or display purposes with a third LED and at least one further first LED and the further second LED, - whereby the first LED and the second LED and the third LED can each assume an on state in which they emit light with a first light output specific for the respective LED, and can each assume an off state in which they each have light emit with a second light output specific to the respective LED and - wherein, based on each LED of these three LEDs, the amount of the first light output of this LED is greater than the amount of the second light output of this LED with the steps Bringing the first LED to its off-state; Bringing the second LED to its off-state; Bringing the third LED to its on state; - Irradiate the first LED with the light of the third LED and Irradiating the second LED with the light of the third LED; - Measuring the photo current or photo voltage of the first LED to determine a first lighting value; - Measuring the photo current or photo voltage of the second LED to determine a second lighting value; - Comparison of the first lighting value with a first threshold value; - Comparison of the second lighting value with a second threshold value; - Evaluation of the second LED as faulty, • if the amount of the first lighting value is greater than the first threshold value and • if the magnitude of the second lighting value is less than the second threshold value. Method for carrying out a test of a first LED of a lamp for lighting or display purposes with a third LED and at least the further first LED and a further second LED, - whereby the first LED and the second LED and the third LED can each assume an on state in which they emit light with a first light output specific for the respective LED, and can each assume an off state in which they each have light emit with a second light output specific to the respective LED and - wherein, based on each LED of these three LEDs, the amount of the first light output of this LED is greater than the amount of the second light output of this LED with the steps Bringing the first LED to its off-state; Bringing the second LED to its off-state; Bringing the third LED to its on state; - Irradiate the first LED with the light of the third LED and Irradiating the second LED with the light of the third LED; - Measuring the photo current or photo voltage of the first LED to determine a first lighting value; - Measuring the photo current or photo voltage of the second LED to determine a second lighting value; - Comparison of the first lighting value with a first threshold value; - Comparison of the second lighting value with a second threshold value; - Evaluation of the first LED as faulty, • if the amount of the first lighting value is less than the first threshold value and • if the magnitude of the second lighting value is greater than the second threshold value.

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