DE102009031403A1 - Light-emitting element for use in lamp, has sensors and controller formed as optical window and arranged on semiconductor substrate, and interface provided for adjustment of light intensity and/or chromaticity coordinates - Google Patents

Abstract

The element has sensors provided for signal analysis of green LEDs (101-104), red LEDs (108, 109) and blue LEDs (110, 111). A controller controls one of the LEDs based on the signal analysis. The sensors and the controller are formed as an optical window (107) and arranged on a semiconductor substrate i.e. application-specific integrated circuit (ASIC) (105). An interface (112) is provided for adjustment of light intensity and/or chromaticity coordinates. The LEDs are arranged in separate LED-strands. An independent claim is also included for a method for operating a light-emitting element.

Description

The The invention relates to a luminous element, a luminaire and a method for operation of the luminous element.

Depending on the temperature, aging and depending on the manufacturing process can an emitted spectrum as well as an emitted optical power of semiconductor light-emitting elements (also referred to as light-emitting diodes or LEDs).

Become several LEDs in the form of clusters of the same or different Color (s) for General, special, or effect lighting used result unwanted Farbortverschiebungen or brightness changes.

at Several clusters result in a noticeable inhomogeneity, as the human eye directly makes a comparison between the emitted spectra juxtaposed cluster and so a relatively small relative change the color location or the brightness is more noticeable.

The The object of the invention is the disadvantages mentioned above and in particular an efficient way to create fluctuations the properties of emitting semiconductor light elements largely compensate.

These Task is performed according to the characteristics of independent claims solved. Further developments of the invention will become apparent from the dependent claims.

• – mit mindestens einer Leuchtdiode;
• – mit einer Sensorik zur Signalauswertung der mindestens einen Leuchtdiode;
• – mit einer Steuerung, die abhängig von der Signalauswertung die mindestens eine Leuchtdiode ansteuert,
• – wobei die Sensorik und die Steuerung als ein Bauelement ausgeführt sind.

To solve the problem, a luminous element is proposed

• - With at least one light emitting diode;
• - With a sensor for signal evaluation of the at least one light emitting diode;
• With a control which, depending on the signal evaluation, drives the at least one light-emitting diode,
• - Wherein the sensor and the controller are designed as a component.

in this connection It should be noted that the sensor system is an electrical and / or optical Signal evaluation of at least one light emitting diode allows.

The The aforementioned luminous element is also referred to as a cluster.

Especially For example, the controller may be or include a controller.

The Light-emitting diode comprises in particular a semiconductor element with light or without housing.

A Continuing education is that the sensors and the control on one Semiconductor substrate, in particular an ASIC, are arranged.

A Another development is that the luminous element has a plurality of light-emitting diodes includes, for example, around the device around, in particular essentially circular or are arranged radially around the component.

Especially It is a development that provides an optic that at least a z. B. predetermined or defined part of the at least a light emitted light on the sensors reflected.

Also It is a training that the component and the at least a light-emitting diode are arranged on a common carrier.

Further It is a training that the lighting element interface for adjusting a brightness and / or a color locus.

at the interface can be, for example, an analog or to a digital interface, in particular to a serial or to act as a parallel interface.

in the Framework of an additional Further development, the controller is set up so that a brightness and / or a color location of the luminous element largely changing over Ambient conditions, in particular temperature and / or ambient brightness, kept constant.

A next Further development is that the lighting element a variety of light-emitting diodes arranged in separate light-emitting diode strands are, each LED strand at least one light emitting diode having, in a time-division multiplexing method per light-emitting diode strand emitted light can be determined.

Especially can in the time-division multiplexing process each light-emitting diode strand separately be controlled, so for the duration of the control that of the affected light-emitting diode strand emitted light can be determined. Depending on that, a continuous or discrete-time setting (control or regulation) of the emitted Light per light-emitting diode strand based on a comparison with a Target for for example, color location and / or brightness.

One embodiment is that, depending on the light detected in the time-division multiplex method each light-emitting diode strand each LED string is adjustable according to a specification.

Especially the control of the light-emitting diode strands can be made such that a desired color location, by the conditions the effective energization of each channel, can be adjusted.

A alternative embodiment is that integration of a photocurrent during a active light phase and during an inactive lighting phase of the at least one light emitting diode (or the at least one light-emitting diode strand) can be carried out and by the difference of the integrated photocurrents one Brightness of the at least one light-emitting diode (or the at least one Light-emitting diode string) can be determined.

By This two-time integration can be an ambient light at least partially be compensated.

A next Embodiment is that the sensors set up for temperature measurement is, in particular by means of a forward voltage of a pn junction (eg by means of dedicated diodes in the sensor system and / or the controller or by means of the transition of the emitted semiconductor) in the forward direction.

Also It is an embodiment that the sensors for brightness measurement is set up, in particular by means of a photosensitivity a reverse current of a pn junction.

A Further development is that the luminous element at least one Having means for optical decoupling of other light sources.

For example can as a means of optical decoupling at least one partition be provided to at least one other light emitting element.

The The above object is also achieved by a lamp or a lighting system comprising at least one luminous element as described herein.

Especially the lamp can a variety of - even different - lighting elements include.

The The above object is also achieved by a method for operating the light emitting element as described herein.

embodiments The invention are illustrated below with reference to the drawings and explained.

It demonstrate:

1 an exemplary construction of a cluster with LEDs and an integrated electronics and integrated sensors in a plan view;

2 according to a cross section through the structure according to 1 ;

3 a block diagram with integrated electronics and integrated sensors;

4 a possible control of two light-emitting diode strands over time comprising an optical measurement of the respective light-emitting diode string in the time-division multiplex method;

5 a diagram illustrating the compensation of the ambient light by means of double integration during the brightness measurement of a light-emitting diode strand;

6 an exemplary construction of a light or a light source comprising a plurality of clusters, each cluster autonomously ensuring a largely constant color location or a largely constant brightness.

The remarks made herein refer by way of example to a cluster comprising a plurality of light emitting diodes. The cluster can also be used as a module or lighting element be designated.

Of the The approach presented here allows integration of electronics and a sensor on a semiconductor substrate that together arranged with light-emitting diodes on a common carrier (eg FR4, AlNi) and wired with these.

A Such an arrangement has the advantage that a cluster of the components Electronics, sensors and light emitting diodes designed to save space can be. Thus, you can after a short development period, new luminaires emerge that contain several clusters comprising one brightness and one color location for each individual clusters independent (from other clusters) is controllable. This means that is a Cluster with the integrated electronics and sensors as at least a light-emitting diode with a constant color locus or spectrum and largely constant brightness behaves.

Another advantage is that a costly construction of discrete electronics on different substrates and their complex connection or contact can be omitted, since preferably the sensor is integrated into the electronics and the entire electronics with sensors as a common component to produce or to can be composed.

Farther Is it possible, by the existing sensors an indirect control of a cross-flow based on the brightness of the cluster. This can be a Efficiency of the cluster can be increased considerably, since no Sense resistors in the high current branch of the LED are needed.

• – Es ergibt sich eine erhebliche Kostenreduktion durch die Integration der Sensorik (z. B. Temperatur- und Helligkeitssensoren) und der Elektronik in ein Halbleitersubstrat.
• – Erhebliche Vereinfachung der Aufbaus des Clusters: Die Elektronik kann mit identischen Werkzeugen bestückt werden wie die Leuchtdioden (Wafer Level Packaging).
• – Mittels eines digitalen Interfaces kann eine Ansteuerung des Clusters (insbesondere mehrerer Cluster) und somit der mindestens einen Leuchtdiode auf dem jeweiligen Cluster deutlich vereinfacht werden.
• – Aufgrund des flexiblen Modulkonzepts (Cluster mit mindestens einer Leuchtdiode, der Elektronik und der Sensorik) ergibt sich eine kompakte (reduzierte) Abmessung für die Elektronik. Neue Leuchten oder Lichtquellen können durch beliebige Kombinationen von Clustern einfach und schnell zusammengestellt werden.
• – Anhand der indirekten Messung des Querstroms über die detektierte Helligkeit kann der Wirkungsgrad deutlich erhöht werden (es sind keine Elemente außer einem Leistungstransistor und mindestens einer Leuchtdiode in dem aktiven Zweig nötig).

Thus, the approach presented here includes in particular the following advantages:

• There is a considerable cost reduction due to the integration of the sensors (eg temperature and brightness sensors) and the electronics into a semiconductor substrate.
• - Substantial simplification of the structure of the cluster: The electronics can be equipped with identical tools as the light-emitting diodes (wafer level packaging).
• A control of the cluster (in particular several clusters) and thus of the at least one light-emitting diode on the respective cluster can be significantly simplified by means of a digital interface.
• - Due to the flexible module concept (cluster with at least one light-emitting diode, the electronics and the sensors) results in a compact (reduced) dimension for the electronics. New lights or light sources can be easily and quickly assembled by any combination of clusters.
• - The indirect measurement of the cross current over the detected brightness, the efficiency can be significantly increased (there are no elements except a power transistor and at least one light emitting diode in the active branch necessary).

Structure of the cluster:

following An example structure of a cluster will be described. The cluster can also be referred to as a module. A light or a Illumination system can be at least one cluster, especially a variety of clusters. Each cluster comprises at least one light-emitting diode, in particular a variety of light emitting diodes. In this case, the individual light-emitting diodes have different colors and / or brightnesses. Especially can in a lighting system clusters with different colors and / or Brightnesses are combined.

1 shows an exemplary structure of a cluster with LEDs and an integrated electronics and integrated sensors in a plan view. 2 shows according to a cross section through the structure according to 1 ,

On a common substrate 106 (eg AlNi) is an ASIC 105 provided, comprising the electronics and the sensor system, wherein the sensor system is an optical window 107 includes. The sensor is preferably arranged approximately in the middle of the cluster.

Green LEDs 101 . 102 . 103 and 104 , red LEDs 108 . 109 and blue LEDs 110 . 111 are around the ASIC 105 arranged around and each connected to this via bonding wires.

Furthermore, the ASIC is via a serial interface 112 connected to a central unit (not shown). Also, the ASIC rejects 105 a connection 113 to earth and a connection 114 to a supply voltage.

The individual LEDs are, for example, on the common substrate 106 applied and with tracks of the common substrate 106 electrically connected via bonding wires.

The Number of for a cluster of light emitting diodes used as well as their colors depend on the type of application. For General lighting could a cluster of white and red LEDs, for example, for effect or special lighting red, green and blue LEDs are used.

As in 1 and 2 shown, the electrical connection of the individual LED strands with the control / control on the common substrate. Only the connections 113 . 114 for the supply voltage and the ground connection as well as the lines 112 for the serial control of the cluster are led away from the substrate.

There as light-emitting diode LED chips without housing, so bare semiconductor light elements (also "bare called the "), can be assembled it is also possible the electronics and / or the sensor in the form of bare semiconductor devices assemble.

Electronics / Sensors:

in this connection It should be noted that the electronics in particular a possibility for controlling and / or regulating the at least one light-emitting diode of the cluster.

3 shows a block diagram with integrated electronics and integrated sensors.

A photodiode 301 delivers z. B. a color location information and / or a brightness signal to a color management 304 , A temperature sensor 303 provides temperature information to the color ma management 304 , Also, the color management can 304 via a serial interface 302 be controlled.

In the color management 304 For example, it is a control unit for the cluster described herein.

The color management 304 controls a driver 305 for supplying a light-emitting diode strand 306 (including, for example, multiple light emitting diodes of the same color or the same type). Accordingly, a driver 307 with a light-emitting diode strand 308 and a driver 309 with a light-emitting diode strand 310 about the color management 304 driven.

Advantageously, the temperature sensor can be based on a silicon-based CMOS process 303 as well as the photodiode 301 be implemented. Thus, it is possible to use a forward voltage of a pn junction (within a Si processing process) in the forward direction for a temperature measurement. Also, a photo-sensitivity of reverse current of the pn junction in the silicon can be effectively utilized as a brightness sensor. By way of example, a possible wavelength range of the photosensor in silicon is between 400 nm and 1000 nm.

In the 3 illustrated serial interface 302 can be used to parameterize possible algorithms of color management 304 be used. So z. B. parameters such as an absolute brightness or a desired color location by means of the serial interface 302 which can be set internally by modifying the effective currents of the respective channels.

The output current of the driver shown 305 . 307 and 309 can be set by analog current regulators or by means of a pulse width modulation (PWM) of a largely constant parametrizable current.

For example, can serve as a manipulated variable, the cross-flow of a light-emitting diode strand and a controlled variable, the brightness of this light-emitting diode strand (determined using the photodiode 301 ) be. By evaluating the brightness of the LED string, it is not necessary to provide separate resistors for determining the current in a high current path of the light emitting diode or of the light emitting diode strand. Accordingly, the efficiency of the solution proposed here increases.

Differentiation of the individual elements:

Especially it can be disadvantageous that emitted light of all light-emitting strands of a Clusters, emitted light of other clusters as well as ambient light is detected by the optical sensor of the cluster and thus influence the regulation of the current cluster.

The individual clusters can be optically decoupled from each other by ensuring that a light power applied by an adjacent cluster is substantially less than the emitted and optically reflected light power of the current module. The light emitted by the current cluster is reflected by the optics and by the optical sensor (eg, the photodiode 301 according to 3 ) detected. In such a case, an optical coupling can be neglected. By way of example, the clusters can be optically largely decoupled from one another by means of suitable partitions.

The Separation of the emitted light output of the individual light-emitting diode strands within of a cluster can efficiently by means of a time division multiplex method For example, after a predetermined number of PWM cycles each light-emitting diode strand of the cluster individually (eg sequentially) and during this Driving the light emitted by the light-emitting diode strand of the optical sensor detected. While controlling a Light-emitting diode strings are the other light-emitting diode strands accordingly switched off, so that only that of the controlled light-emitting diode strand emitted light is detected by the optical sensor. After all Light-emitting diode strands one Clusters are measured, the common control of the light-emitting diode strands z. B. continued in PWM mode. This measurement of the individual light-emitting diode strands in the time-division multiplex method can be repeated at predetermined times (eg regularly). Corresponding of the light detected per light-emitting diode strand this is controlled or changes compensated. This allows a constant lighting behavior for everyone single light-emitting diode strand of the cluster.

There each cluster operated separately according to the approach described here can be, respectively Temperature changes, Aging or other different conditions efficiently compensated become a user and a consistent lighting impression mediated even when using multiple clusters.

4 shows by way of example a possible control of two light-emitting diode strands (channel 0 and channel 1) over the time t comprising an optical measurement of the respective light-emitting diode string in the time-division multiplex method.

During a time period 401 will the Light-emitting diode strings are controlled and measured one after the other: First of all, channel n is activated by means of a signal 402 , then the channel 1 is driven by means of a signal 403 , The control takes place in the time domain 401 exclusively for one channel each, ie a photodiode of the cluster detected during the duration of the signal 402 the light emitted by the channel n and during the duration of the signal 403 the light emitted from the channel 1. Starting from the respective detected signals, an adjustment or regulation of the respective channel takes place, so that, for example, an impression of a constant color location at constant brightness is produced. For this purpose, it is preferable to regularly repeat the time range 401 provided for setting or readjustment of the individual channels or light-emitting diode strands.

in this connection It should be noted that each light-emitting diode strand at least one light emitting diode having. In particular, you can per LED string different numbers of LEDs be provided. Said LEDs can light emitting diodes with or without ("bare the") casing include.

Farther Is it possible, the influence of ambient light by double integration of the photocurrent to attenuate by the optical sensor. When the photocurrent is in a PWM "high" state (i.e., the light emitting diode strand is actively energized) "integrated" and in the following PWM "low" state (i.e. Light-emitting diode strand is not energized) "integrated", corresponds to that Result of this twice integration of the actually emitted light quantity of the light-emitting diode strand without an "offset" caused by the ambient light.

5 shows a diagram for illustrating the compensation of the ambient light by means of double integration during the brightness measurement of a light-emitting diode strand.

During a period of time 501 _If the light-emitting diode string is _activated , the photocurrent is integrated from a value I _phl to a value I _ph2 . Subsequently, the light-emitting diode strand for a period of time 502 off. The photocurrent is disintegrated and reduced to a value I _ph3 . The difference I _ph3 - I _ph1 corresponds to the actual brightness change during the time period 501 adjusted for the contribution of ambient light.

Module concept:

6 shows an exemplary construction of a light or a light source comprising a plurality of clusters 601 to 606 Each cluster autonomously ensures a largely constant color location or a largely constant brightness.

The arrangement of 6 includes partitions 607 between the clusters that reduce or compensate for direct irradiation by the neighboring modules.

Preferably, each cluster comprises 601 to 606 an optic that at least partially allows reflection of the emitted light in the direction of the optical sensor of the respective cluster.

R

rot,

G

grün,

B

blau,

W

weiß,

Y

gelb.

By way of example, different cluster types can be combined with each other. Such are the clusters 601 and 603 of type "RGB", the clusters 602 and 605 are of type "WR" and the clusters 604 and 606 are of the type "RYB"; here the abbreviations designate:

R

red,

G

green,

B

blue,

W

White,

Y

yellow.

The Cluster of type RGB has z. B. two red, two green and two blue LEDs on. The cluster of type WR includes z. Six white and two red LEDs. The cluster of type RYB has two red, two yellow and two blue LEDs.

Corresponding can any cluster with different numbers of LEDs be used in different colors together in one lamp.

LIST OF REFERENCE NUMBERS

101

led (green)

102

led (green)

103

led (green)

104

led (green)

105

ASIC

106

substratum

107

optical Window for sensors

108

led (red)

109

led (red)

110

led (blue)

111

led (blue)

112

serial interface

113

connection to earth

114

connection to the supply voltage

301

photodiode

302

serial interface

303

temperature sensor

304

Color Management

305

driver

306

LEDs strand

307

driver

308

LEDs strand

309

driver

310

LEDs strand

401

time range

402

control signal for channel n

403

control signal for channel 1

501

time (for "on" integration)

502

time (for "down" integration)

601

RGB cluster

602

WR cluster

603

RTB cluster

604

RYB cluster

605

WR cluster

606

RYB cluster

607

partitions

Claims (15)

Light-emitting element - with at least one light-emitting diode ( 306 . 308 . 310 ); - with a sensor system ( 302 . 303 ) for signal evaluation of the at least one light emitting diode; - with a controller ( 304 ), which activates the at least one light-emitting diode depending on the signal evaluation, - the sensor system and the control being used as one component ( 105 . 107 ) are executed. Luminous element according to claim 1, wherein the sensor and the controller on a semiconductor substrate, in particular a ASIC, are arranged. Luminous element according to one of the preceding claims, comprising a plurality of light-emitting diodes which are arranged around the component. Luminous element according to one of the preceding claims, at an optics is provided which at least a part of the light emitted by at least one light-emitting diode is reflected onto the sensor system. Luminous element according to one of the preceding claims, wherein the component and the at least one light-emitting diode on a common carrier ( 106 ) are arranged. Luminous element according to one of the preceding claims, with an interface for setting a brightness and / or a Color location. Luminous element according to one of the preceding claims, at the controller is set up such that a brightness and / or a color location of the luminous element are kept substantially constant. Luminous element according to claim 7, with a plurality of light-emitting diodes arranged in separate light-emitting diode strands wherein each light-emitting diode strand has at least one light-emitting diode, wherein in a time-division multiplexing method per light-emitting diode strand emitted light can be determined. Luminous element according to claim 8, wherein depending on the time-multiplexed light per light-emitting diode strand each light-emitting diode string is adjustable according to a specification. Luminous element according to one of claims 7 to 9, wherein an integration of a photocurrent during an active lighting phase ( 501 ) and during an inactive lighting phase ( 502 ) of the at least one light emitting diode is feasible and based on the difference of the integrated photocurrents a brightness of the at least one light emitting diode can be determined. Luminous element according to one of the preceding claims, at the sensor is set up for temperature measurement, in particular by means of a forward voltage of a pn junction in the forward direction. Luminous element according to one of the preceding claims, at in which the sensors for brightness measurement is set up, in particular by means of a photosensitivity of a reverse current of a pn junction. Luminous element according to one of the preceding claims with at least one means for optical decoupling from other light sources. Luminaire comprising at least one luminous element after one of the preceding claims. Method for operating a lighting element after one of the claims 1 to 13.

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