DE102009005552A1 - Apparatus for testing radial symmetry of radiation of side emitting LEDs used in headlamp of motor vehicle, has evaluation device evaluating measuring signals of sensors during electrical contacting of LEDs with respect to radial symmetry - Google Patents

Abstract

The apparatus (1) has a transport device for transporting LEDs (2) along a section (11) of a transport path (12) passing through a center point (6), such that each LED with its optical axis is aligned parallel to a center axis. A contact device electrically contacts the LEDs during passing of the contact device to the point. An evaluation device is connected with the sensors and contact device. The evaluation device evaluates measuring signals of sensors (5) during contacting of the LEDs, which are present in the center point, with respect to radial symmetry of radiation of the LEDs. An independent claim is also included for a method for testing radial symmetry of radiation of side emitting LEDs.

Description

The The invention relates to a device and a method for testing the radial symmetry of the emission of laterally emitting light-emitting diodes (LEDs) according to the preamble of claim 1 and of Claim 14.

By the EP 1 881 258 A1 is a side emitting LED consisting of an LED chip and a downstream Lichtverteilkörper known. The light emitted by the LED chip is deflected by the light distribution body. The LED has a high intensity of the light emitted by it. In addition, the LED has a light distribution whose intensity along the optical axis is almost zero and the intensity maximum, depending on the design of the Lichtverteilkörpers at an angle of about 45 ° to 90 ° to the optical axis.

A Such LED is used for example in lights for motor vehicles used. The LED emits its light into one, for example reflector arranged symmetrically around the optical axis of the LED, the light then in the direction of a desired direction of emission the light deflects. In such a lamp is a uniform Appearance desired, in which the LED in the lamp is not perceived punctiform. This is a uniform Light distribution required, where the light from the LED off Direction of the optical axis of the LED considered with high intensity homogeneously distributed around the optical axis in the reflector becomes.

Around this and similar requirements must be met be sure that such side emitting LEDs a uniform, radial light distribution or a have high radial symmetry of the radiation.

commercial Sorters, such as those commonly used for quality control, mainly radiating in the direction of the optical axis LEDs are used to such a review not suitable because they are unable to provide lateral radiation to record and evaluate in several spatial directions.

By the DE 199 26 036 C1 An arrangement for measuring the power of a radiation source is known. The arrangement comprises a cavity whose inner walls are completely or partially covered with detectors. The detectors respectively generate proportional measurement signals to the parameters of the radiation source to be measured. The measurement signals are further processed into a sum signal, whereby the sum signal is independent of the radiation characteristic and the position of the radiation source in the cavity. The known arrangement is therefore not suitable for checking the radial symmetry of the emission of laterally emitting LEDs.

By the DE 44 23 802 A1 is an optical sensor for detecting the radiation characteristic of a radiation source in a large solid angle known. The optical sensor consists of a lens body, which converts the radiant flux emanating from the radiation source into a parallel bundle such that no mixing of the radiant flux emitted in different spatial directions takes place. The parallel beam is incident on a detector in the form of a planar, spatially resolving optoelectric transducer. For spatial resolution, the optoelectric converter has a pixel array. Each pixel of the opto-electrical converter thus detects a defined point of the half-space into which the radiation source radiates.

Although the known sensor is fundamentally suitable for checking the radial symmetry of the emission of laterally emitting LEDs. However, it has the disadvantage that its use has a complicated handling of the LEDs to be checked with a large number of individual, time-consuming expiration or movement steps per LED result. Thus, each individual LED must first be supplied to the sensor, then immersed in the lens body and then the LED contacted electrically, before the actual review can take place. After the check, the electrical contact of the LED must be removed, the LED should be withdrawn from the lens body and then the LED should be removed. The flow or movement steps are also discontinuous in that each expiration or movement step due to the complicated handling of the LEDs must be carried out individually and with dedicated, separate facilities. The execution of these sequence or movement steps is therefore very time-consuming and also requires for each individual flow or movement step own facilities that can be difficult or impossible to integrate, for example, in a continuous process. The sensor is therefore not suitable for use, for example, in a quality control immediately after a production plant in which all produced LEDs are to be checked. In addition, due to the complex and costly separating devices, grippers, actuators, etc. required for carrying out the individual sequence or movement steps, there is also a high risk of failure, which would lead to a standstill of the entire production system in the example given. The necessary separating devices, grippers, actuators, etc. also leave no starting points for the use of synergies in a continuous Pro recognize it.

By the DE 36 34 597 A1 For example, a method and an arrangement for measuring the radiance or the spatial distribution of the radiant flux of a radiation source are known. A stationarily arranged detector is connected to a first, an outcoupling surface forming end of an optical waveguide. The one coupling surface of the light guide forming the second end is free. The free end is used to tap the radiation flow in different directions gradually and fed to the detector for measurement.

The known method and the known arrangement a very time-consuming Departure of all relevant spatial directions required. This is too time consuming for integration, for example Quality control in or after one Production process. The method is thus only for random sampling Quality control suitable.

Summarized It can be stated that it is from the state of the art though is known, the radial symmetry of the emission side emitting LEDs check the state of the art though not suitable, such a review, for example for quality control at the end of an ongoing production facility or within a production process, not just random, but to perform on any manufactured LED with reasonable effort. If the state of the art would be used for this, on the one hand, this would be very time consuming and required on the other hand, complicated procedural movements.

Of the Invention is therefore the object of a device as well a method for testing the radial symmetry of the radiation to develop laterally emitting LEDs, which preferably a complete and quick examination of a large one Number of LEDs z. B. in the context of a quality control z. B. following a manufacturing process.

The Task is solved by a device with the features of claim 1 or by a method having the features of the claim 14th

• – eine symmetrische Anordnung von jeweils der Intensität des Lichts der LEDs proportionale Messsignale erzeugenden Sensoren um eine durch einen Mittelpunkt hindurchführende Mittelachse herum;
• – eine LEDs z. B. einzeln oder in Gruppen nacheinander zumindest entlang eines durch den Mittelpunkt hindurchführenden Abschnitts einer Transportbahn derart transportierende Transporteinrichtung, dass jede LED oder jede Gruppe von LEDs zumindest während ihres Passierens des Mittelpunkts mit ihrer optischen Achse parallel zur Mittelachse ausgerichtet ist bzw. in Richtung der Mittelachse steht;
• – eine die jeweils den Mittelpunkt passierenden, von der Transporteinrichtung transportierten LEDs oder Gruppen von LEDs zumindest während deren Passage des Mittelpunkts elektrisch kontaktierende Kontaktiereinrichtung;
• – eine mit den Sensoren und mit der Kontaktiereinrichtung verbundene, die einzelnen Messsignale der Sensoren während der elektrischen Kontaktierung der sich jeweils im Mittelpunkt befindenden LED oder Gruppe von LEDs im Hinblick auf deren Radialsymmetrie der Abstrahlung beispielsweise durch Vergleich der einzelnen Messsignale mit- bzw. untereinander auswertenden Auswerteeinrichtung.

A first subject of the invention accordingly relates to a device for testing the radial symmetry of the emission of laterally emitting LEDs. Such a device comprises according to the invention:

• - A symmetrical arrangement of each of the intensity of the light of the LED proportional measuring signals generating sensors around a passing through a center center axis around;
• - a LEDs z. B. individually or in groups successively at least along a passing through the center portion of a transport path transporting device such that each LED or group of LEDs is aligned at least during their passing of the center with its optical axis parallel to the central axis or in the direction of the central axis stands;
• - One each passing the midpoint, transported by the transport device LEDs or groups of LEDs at least during their passage of the center electrically contacting contacting device;
• - An associated with the sensors and with the contacting, the individual measurement signals of the sensors during the electrical contacting of each located in the center LED or group of LEDs with respect to their Radialsymmetrie the radiation, for example, by comparing the individual measurement signals mit- or evaluating each other evaluation.

advantages The invention over the prior art arise in particular, that with the present solution a standard test of radial symmetry the radiation, for example, of all in a production process produced, laterally emitting LEDs, for example, in the immediate Connection to their production is possible.

Further Advantages of the invention over the prior art arise, among other things, that the device without complicated Expiry movements executing institutions. When Transport device is sufficient, for example, a disc or a wheel or the LEDs, preferably vertically transporting Conveyor, in which the LEDs, for example, standing with their Contact feet can be used and in the already more electrical tracks of the Contacting device can be integrated, with which the contact feet of the LEDs when they are inserted in the conveyor belt can be brought into contact. The Device according to the invention allows a fast measuring time or a short test duration and thereby a 100% control following a production plant with appropriate Classification of the manufactured LEDs.

Preferably the transport device operates clocked, with a single LED or a group of LEDs between two consecutive Clocks located in the center of the symmetrical arrangement and while is contacted electrically by means of the contacting device.

The transport device can at least with the individual or groups of LEDs comprise at least temporarily electrically connected interconnects, which are part of the contacting device.

A advantageous embodiment of the invention Device sees a perpendicular to the central axis round or polygonal Cross-section of the symmetrical arrangement before. The polygonal cross section may be six or octagonal, for example. The symmetrical Arrangement thus has a particularly inexpensive feasible, simple Geometry on.

Especially Preferably, the transport path runs in a plane. Especially Preferably, at least that passes through the center passing section of the transport path in a plane.

A particularly advantageous embodiment of the invention Device provides that the transport path or at least the one Section of the transport path, along which the transport device the LEDs are transported, free of reversal points. This can the transport device run along the entire transport path and moreover, particularly inexpensive, simple and Fail-safe, for example in the form of a conveyor belt, a rotating wheel or a rotating disk.

The Transport path can at least partially in a circular arc run or the transport device, the LEDs at least partially transport in a circular arc.

The Transportation path can also be a circular path. The transport device may in this case include a disc, a wheel or the like, to the outer circumference of the LEDs at least one Section of the circular path to be transported. Is one by the Disc formed plane normal to the central axis, the LEDs become z. B. transported on the circumference in the axial direction standing. Is a plane formed by the disc parallel to the central axis, the LEDs are transported lying on the circumference in the radial direction. Likewise, a skewed arrangement of disc axis to the central axis conceivable. As a result, by the transport device with simple Means a complex sequence of movements are realized, in which z. B. on a feeder belt LEDs picked up, lifted, aligned with its optical axis parallel to the central axis and then z. B. in one or more sorting funnel be dropped.

Preferably At least that runs through the center Section of the transport path along a straight line.

A Another preferred embodiment of the invention Device provides that the symmetrical arrangement in one Cavity with preferably blackened walls is arranged, with the leading through the center Section of the transport path through slots or openings into the cavity and again out of the cavity or leads.

• – symmetrisches Anordnen von jeweils der Intensität des Lichts der LEDs proportionale Messsignale erzeugenden Sensoren um eine durch einen Mittelpunkt hindurchführende Mittelachse herum;
• – Transportieren von LEDs z. B. einzeln oder in Gruppen nacheinander zumindest entlang eines durch den Mittelpunkt hindurchführenden Abschnitts einer Transportbahn auf eine Art und Weise, so dass jede LED oder jede Gruppe von LEDs zumindest während ihres Passierens des Mittelpunkts mit ihrer optischen Achse parallel zur Mittelachse ausgerichtet ist bzw. in Richtung der Mittelachse steht;
• – Elektrisches Kontaktieren der jeweils den Mittelpunkt passierenden LEDs oder Gruppen von LEDs zumindest während deren Passage des Mittelpunkts;
• – Auswertung der Messsignale der Sensoren während des elektrischen Kontaktierens der sich jeweils im Mittelpunkt befindenden LED oder Gruppe von LEDs im Hinblick auf deren Radialsymmetrie der Abstrahlung.

A second object of the invention relates to a method for testing the radial symmetry of the emission of laterally emitting LEDs. Such a method according to the invention comprises the method steps:

• Symmetrically arranging sensors, each generating signals proportional to the intensity of the light of the LEDs, about a central axis passing through a center;
• - Transporting LEDs z. B. individually or in groups successively at least along a passing through the center section of a transport path in a manner such that each LED or group of LEDs is aligned at least during their passage of the center with its optical axis parallel to the central axis or in Direction of the central axis is;
• - electrically contacting each of the center passing LEDs or groups of LEDs at least during their passage of the center;
• - Evaluation of the measurement signals of the sensors during the electrical contacting of each located in the center of the LED or group of LEDs in terms of their radial symmetry of the radiation.

Preferably the transport of the LEDs takes place at least along the center passing section of the transport path free of Reversal points. This will not be complicated facilities needed to handle the LEDs during the test. The method and a method performing the method are thus easy, inexpensive and without high risk of default as in the prior art, for example, following a Production process or integrated after a production plant.

One Embodiment of an inventive Device is shown in the drawings and will become hereafter explained in more detail. Show it:

1 a schematic representation of a device according to the invention in a plan view.

2 a schematic representation of a four sensors of the device 1 forming, consisting of sixteen individual photodiodes Photodiode array in a front view ( 2a ), in a side view ( 2 B ) and in a plan view ( 2c ).

3 a schematic representation of a control board one with sensors of the device 1 associated evaluation device.

4 a schematic representation of the device 1 in a perspective view.

One in the 1 and 4 illustrated inventive device 01 for testing the radial symmetry of the emission of laterally emitting LEDs 02 includes a symmetrical arrangement 03 each of the intensity of the schematically by light rays 04 represented light of the LEDs 02 generating proportional measuring signals, for example by in 2 closer illustrated photodiode fields 05 formed sensors 15 one through a center 06 passing center axis around. The symmetrical arrangement 03 is in one of blackened walls 07 enclosed cavity 08 , Through slots 09 . 10 one leads along one through the center 06 leading section 11 a transport path 12 extending transport device 13 in the cavity 08 in and out again. The transport device 13 transports LEDs 02 z. B. individually or in groups successively at least along the through the center 06 passing section 11 the transport track 12 such that every LED 02 or any group of LEDs at least while passing the center 06 with its optical axis parallel to the in 1 is oriented perpendicular to the image plane extending central axis or is in the direction of the central axis. The transport direction of the transport device is indicated by the arrow 14 indicated. A contact means, not shown in each contacted the center 06 passing, from the transport device 13 transported LEDs 02 or groups of LEDs at least during their passage of the center 06 electric. An in 3 shown, with the through the photodiode arrays 05 formed sensors 15 and control board connected to the contacting device 16 one with the sensors 15 connected evaluation evaluates the individual measurement signals of the sensors 15 during the electrical contacting of each in the center 06 located LED 02 or group of LEDs 02 with regard to their radial symmetry of the radiation, for example by comparison of the individual measurement signals mit- or with each other.

In one of the in 1 shown top view, perpendicular to the central axis extending cross section has the symmetrical arrangement 03 an octagonal or octagonal cross section, in the eight photodiode arrays 05 around the center 06 passing center axis are arranged around. The individual photodiode fields 05 For example, the following theta angles τ _i = 22.5 ° + i · 45 ° cover with i = 0 ... 7.

Each of these eight photodiode arrays 05 includes, for example, sixteen individual photodiode cells 17 each having an active area of, for example, 1.305 mm ² , in a ceramic body 18 are housed ( 2 ). Of the sixteen individual photodiodes 17 each are four photodiodes 17 connected in parallel and thus form a sensor 15 with a total active area of 5.52 mm ² . Every sensor 15 becomes an input channel one in 3 illustrated control board 16 assigned.

The measuring signals of the individual 8 × 4 channels are made using, for example, the control board 16 comprehensive data acquisition card and, for example, a measurement program, which are both components of an evaluation, read and evaluated. It is important to emphasize at this point that the evaluation device is a personal computer.

The LEDs 02 be by means of the transport device 13 automatically through the wall 07 arranged slot 09 in the cavity 08 transported in and in the center 06 the symmetrical arrangement 03 positioned sensor carrier positioned in the center of the symmetrical arrangement. The transport device 13 works preferably clocked. For example, the focus is on between two consecutive bars 06 located and electrically contacted by means of the contacting LED 02 is briefly activated and then be in, for example, thirty-two spatially distributed directions using the sensors 15 the individual light intensities recorded. The values are compared by means of the evaluation device and the emission characteristic of the LED 02 evaluated for radial symmetry. Subsequently, the transport device transports 13 the thus tested LED 02 through the slot 10 in the wall 07 from the cavity 08 out.

An examination or an evaluation of the emission characteristic of the laterally emitting LEDs 02 happens at the device 01 by measuring the light intensity at a total of thirty-two positions. Each of these thirty-two positions is through each of four photodiode cells 17 formed sensors 15 the total of eight, sixteen photodiode cells each 17 comprehensive photodiode fields 05 given. The position of each one sensor 15 the device 01 forming group of four photodiode cells 17 defines a detected solid angle of the measurement.

It is important to emphasize that with the device according to the invention 01 in addition to a by comparing the individual channels with each other or taking place qualitative testing of the radial symmetry of the emission of laterally emitting LEDs 02 basically also a quantitative test of the intensity of the emitted light 04 is possible.

The number and arrangement of the sensors 15 , Photodiode cells 17 or photodiode arrays 05 can be varied depending on the application, for example, for a mounting optics on chip on board (COB) LEDs or Surface Mounted Device (SMD) LEDs. In this case, not a single LED 02 but a for example a group of LEDs complete circuit board in the center 06 the device 01 drive.

Important It should be emphasized that even a symmetrical arrangement of two opposite, consisting of one sensor field optical Walls is conceivable, as for example from the lighting technology is known for the measurement of luminaires. By a multi-sided symmetrical arrangement of the sensors around the center and an in-center LED around, as described above, However, the result of the review is essential more precisely, since all considered solid angles are detected at the same distance.

The Invention is particularly in the field of production of the side radiating LEDs industrially applicable.

01

contraption

02

LED

03

symmetrical arrangement

04

beam of light

05

Photodiode array

06

Focus

07

wall

08

cavity

09

slot

10

slot

11

section

12

transport path

13

transport means

14

transport direction

15

sensor

16

control board

17

Photodiodes cell

18

ceramic body

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 1881258 A1 [0002]
• - DE 19926036 C1 [0006]
• - DE 4423802 A1 [0007]
• - DE 3634597 A1 [0009]

Claims (15)

Device for testing the radial symmetry of the emission of laterally emitting light-emitting diodes (LEDs), characterized by a symmetrical arrangement of the intensity of the light ( 04 ) of the LEDs ( 02 ) proportional measuring signals generating sensors ( 05 . 15 . 17 ) one by one ( 06 ) passing center axis around; - one LEDs ( 02 ) at least along one through the midpoint ( 06 ) passing section ( 11 ) a transport path ( 12 ) such transporting transport device ( 13 ), that each LED ( 02 ) at least during its passage through the center ( 06 ) is aligned with its optical axis parallel to the central axis; - one the LEDs ( 02 ) at least during its passage from the midpoint ( 06 ) electrically contacting contacting device; - one with the sensors ( 05 . 15 . 17 ) and connected to the contacting device, the measuring signals of the sensors ( 05 . 15 . 17 ) during the electrical contacting of each in the center ( 06 ) LED ( 02 ) with regard to their radial symmetry of the evaluation evaluating evaluation. Apparatus according to claim 1, characterized in that the transport device ( 13 ) is clocked, whereby a single LED ( 02 ) between two consecutive bars ( 06 ) of the symmetrical arrangement ( 03 ) and in the meantime is contacted electrically by means of the contacting device. Apparatus according to claim 1 or 2, characterized in that the transport device ( 13 ) at least with the LEDs ( 02 ) comprises at least temporarily electrically connected conductor tracks, which are part of the contacting device. Device according to one of the preceding claims, characterized by a cross section of the symmetrical arrangement which is circular in relation to the central axis ( 03 ). Device according to one of claims 1 to 3, characterized by a cross-section perpendicular to the central axis of the symmetrical arrangement ( 03 ). Apparatus according to claim 5, characterized by a hexagonal cross-section. Apparatus according to claim 5, characterized by an octagonal cross-section. Device according to one of the preceding claims, characterized in that the transport path ( 12 ) runs at least in sections in a plane. Device according to one of the preceding claims, characterized in that the transport path ( 12 ) is free from reversal points. Device according to one of the preceding claims, characterized in that the transport path ( 12 ) runs at least in sections in a circular arc. Device according to one of the preceding claims, characterized in that the transport path ( 12 ) is a circular path. Device according to one of claims 1 to 10, characterized in that at least by the center ( 06 ) leading section of the transport path ( 12 ) runs along a straight line. Device according to one of the preceding claims, characterized in that the symmetrical arrangement ( 03 ) in a cavity ( 08 ) with preferably blackened walls ( 07 ), which passes through the center ( 06 ) leading section ( 11 ) of the transport path ( 12 ) through slots ( 09 . 10 ) or openings ( 09 . 10 ) in the cavity ( 08 ) into and out again. Method for testing the radial symmetry of the emission of laterally emitting light-emitting diodes (LEDs), characterized by the method steps: symmetrical arrangement of the intensity of the light of the LEDs ( 02 ) proportional measuring signals generating sensors ( 05 . 15 . 17 ) one by one ( 06 ) passing center axis around; - transporting LEDs ( 02 ) at least along one through the midpoint ( 06 ) passing section ( 11 ) a transport path ( 12 ), so each LED ( 02 ) at least during its passage through the center ( 06 ) is aligned with its optical axis parallel to the central axis; - electrically contacting the LEDs ( 02 ) at least during its passage from the midpoint ( 06 ); - Evaluation of the measuring signals of the sensors ( 05 . 15 . 17 ) during the electrical contacting of each in the center ( 06 ) LED ( 02 ) with regard to their radial symmetry of radiation. Method according to claim 14, characterized in that the transport of the LEDs ( 02 ) at least along the through the center ( 06 ) passing section ( 11 ) of the transport path ( 12 ) free from reversal points.