DE102008009680A1 - Sensor device for three-dimensional measurement of e.g. flip chip, in manufacturing system, has camera unit to record object under observation direction, which together with illumination direction includes angle differ from zero - Google Patents

Abstract

The sensor device (130) has sensor modules (140) attached at a base element i.e. base plate. The sensor modules exhibit an illumination unit and a camera unit. The illumination unit is arranged for illuminating an object i.e. electronic component, to be measured under an illumination direction. The camera unit is arranged for recording the object to be measured under an observation direction, which together with the illumination direction includes a triangulation angle that differs from zero. Independent claims are also included for the following: (1) a method for three-dimensional measurement of electronic component, attached on an electronic switching substrate according to triangulation principle (2) a system for manufacturing an electronic component.

Description

The The present invention relates to the technical field of three-dimensional optical measurement of objects. The invention particularly relates an optical sensor device for three-dimensional surveying of objects according to the principle of triangulation. The invention relates Furthermore, a system for manufacturing electronic assemblies, which a placement device and an inspection device, wherein the inspection device a sensor device of the above type. It also concerns the invention a method for the three-dimensional measurement of Objects according to the principle of triangulation by means of a sensor device of the above type.

In Considering the increasing miniaturization of device-based electronic devices Assemblies not only require a high-precision assembly of component carriers to ensure with electronic components, rather it is in view of a high production security also important quality to check the manufactured assemblies regularly. This happens in the Usually by means of a so-called. Automatic Optical Inspection (AOI), in both the position of the individual components on the component carrier as also the respective type of stocked Component is checked. For that can in addition to a two-dimensional inspection also a three-dimensional (3D) Measurement of the height profile a stocked Component carrier are performed.

A 3D inspection is typically based on triangulation measurements. It uses projection patterns and projection sequences, to determine the coordinate of the third dimension. The principle the height calculation by means of structured illumination is based on the lateral displacement of an oblique Angle projected pattern due to the respective object height at one certain place.

The lateral displacement x becomes over the mapping scale β on the Transmit sensor of the observation system of a triangulation sensor. The relationship between the lateral displacement Δx, the lateral Displacement Δx 'in the image plane of the observation system and the object height h at the respective point the surface of the DUT is described by the following formulas.

there θ is the so-called triangulation angle, i. H. the angle, the lighting beam and the observation beam within of the triangulation level.

at the so-called phase triangulation becomes a sinusoidal intensity profile projected onto the test object. The lateral displacement Δx causes a shift in the phase position of the sine grating. By for each Pixels for different projected phase positions measured the intensity the phase and thus the spatial coordinates can be determined precisely.

With the phase shift Φ the height can be calculated with the following formula:

there p is the grating period or the period length of the sine grating.

Around a stocked Component carrier completely in To measure 3D, It is known to use a triangulation sensor with a comparatively high sensor performance, d. H. especially with a wide field of vision and a high-quality and therefore also expensive optics, by means of a positioning system to proceed and in different places each a comparatively small area of the populated component support to measure in 3D. The 3D frames can then by means of a suitable Image processing software to an overall picture together.

In Considering the constant However, increasing cost pressure in electronics production is required, including the cost of to limit the AOI. The same goes for the speed of one AOI measurement, which can be carried out within the shortest possible test time should.

Of the The present invention is based on the object, the 3D inspection of measuring objects such as electronic assemblies in particular in terms of the cost of a corresponding sensor system and the speed with which the 3D survey can be performed to improve.

This object is solved by the subject matters of the independent claims. advantage Embodiments of the present invention are described in the dependent claims.

According to one The first aspect of the invention is a sensor device for three-dimensional surveying described by objects according to the principle of triangulation, which in particular for the three-dimensional measuring of on an electronic Circuit substrate applied components is suitable. The described sensor device comprises (a) a base element, (b) a first sensor module attached to the primitive; and (c) a second sensor module attached to the base member. The first Sensor module and the second sensor module each have a lighting unit and a camera unit. Furthermore, the lighting unit is set up for illuminating an object to be measured under an illumination direction and the camera unit is arranged to detect the one to be measured Object under an observation direction, together with the direction of illumination includes a non-zero triangulation angle.

the described modular triangulation sensor is the Understanding that by a suitable combination of several individual triangulation modules a large spatial area even then Completely can be measured if each individual triangulation module respectively can cover only a comparatively small area. It can in an advantageous way to the rapid developments in recent years used in camera technology become. These developments have led, for example, to inexpensive Digital cameras camera sensors have been developed at very low cost already have an excellent image-recording quality. This allows the described modular triangulation sensor of the in the Consumers industry created standards and their inexpensive Components benefit. Cost-intensive and expensive new developments for special cameras, with which a comparatively large spatial area with the therein located three-dimensional objects can be measured are by the modular construction of the described triangulation sensor and the possibility the use of conventional Standard components not required.

Regarding the number of sensor modules required for the described triangulation sensor be suitably mitein other can be combined there is no principal limit. So can for each application depending on the size of the a suitable number of sensor modules summarized and suitably attached to the base member. This means that also very big Areas by using a correspondingly high number of Sensor modules can be inspected three-dimensionally. In Considering the inexpensive realization possibility of the individual sensor modules This is usually cheaper than a well-known Measuring device with only one triangulation sensor and one Positioning system with which the triangulation sensor moves spatially can be. The avoidance of moving parts also has the advantage that elaborate precision axes as well high-precision standards are not are required and still achieve a very high measurement accuracy is. The avoidance of moving parts also has the advantage that a three-dimensional inspection with the described modular Triangulation sensor usually be performed much faster can.

It It should be noted that the described triangulation sensor not just for the three-dimensional measurement of one in a given one Object located at the measuring field (thereby being detected by different sensor modules detecting different parts of the object) can be used. The described modular triangulation sensor is suitable also for measuring assemblies, which have a plurality of may have different individual objects. The individual objects can, for example electronic components or solder paste or SMD solder joints which may be on a circuit substrate or any component support are located.

Under The term components are in this application in principle all suitable elements understood, in particular electronic components, electromechanical Components, optoelectronic components, connectors and plug connections for electrical and mechanical contacts and shielding plates. The term electronic components itself includes a variety of different types of components, For example, SMD components (Surface Mount Device components) and highly integrated flat Components. These include for example, BGA's (Ball Grid Arrays), Bare Dies and Flip Chips.

According to one embodiment According to the invention, the sensor device additionally has at least one additional one Sensor module, which is also a lighting unit for Illuminating an object to be measured under a lighting direction and a camera unit for detecting the object to be measured under a different observation direction from the direction of illumination includes. The first sensor element, the second sensor element and the at least one further sensor element form a one-dimensional or a two-dimensional array.

The individual sensor modules can For example, means of their respective housing to a linear or to a plane Be concatenated array. It can the sensor modules each have a defined grid location of the respective Occupy arrays. This allows the overall size and the entire Measuring field of the described triangulation sensor problem specific adapted to the respective technical requirements. Thus, can Ensuring that a customer is not forced to possibly for his measurement requirement too big To buy triangulation sensor. Thus, one request can always be made for each request cost-effective Triangulation sensor can be offered with full measurement accuracy.

So can, for example, in the three-dimensional inspection of populate component carriers the Number and dimension of the triangulation sensor to be used to the dimensions of the tested Printed circuit boards or component carriers be adjusted.

According to one another embodiment of the Invention are the fields of view of the sensor modules on an object plane each at least as big as the lateral dimensions of the respective sensor modules. This means, that the width of the respective field of vision in no case smaller may be as the lateral housing dimensions of the respective sensor module. It is assumed that the sensor modules in each case completely in a sensor module housing are housed.

Of the The triangulation sensor described thus has a field of view for each module on, which projected on the object plane in the array direction larger or equal to the mechanical dimensions of the module. It will be If necessary, also consider adapter elements for the mechanical dimensions the for the above-described concatenation of the individual sensor modules required could be.

The Adjust the size of the visual fields to the lateral dimensions of the sensor modules has the advantage that in building the described modular triangulation sensor the spatial Layers of the fields of view of the individual sensor modules in such a way can be tuned, that the triangulation sensor overall in its entire field of view no gaps having. As a result, the described triangulation sensor for a gapless Three-dimensional inspection, for example, from a mounted on a component carrier electronic Assembly can be used.

According to one another embodiment of the Invention, the sensor device additionally has at least one mechanical Adjusting device, which is set up such that the relative spatial Spacing between different sensor modules is adjustable. Such a mechanical adjusting device has the advantage that the fields of view of the individual sensor modules in the object plane Ideally, without gaps can be put together to a total field of view. The Adjusting device can be several individual adjusting devices each having a single adjusting device between two adjacent sensor modules is arranged.

According to one another embodiment of the Invention, the individual sensor modules are arranged such that the fields of view of two directly adjacent sensor modules at least one predetermined overlap exhibit.

The Provide a conscious overlap between adjacent fields of view has the advantage that at the manufacture and / or operation of the described sensor device an exact and possibly expensive adjustment of the individual sensor modules can be dispensed with each other. On the above described and possibly mechanically quite complicated adjustment can then be dispensed with become.

It it is noted that by a deliberate overlap in the overlap area the illumination intensity due to the double lighting can be significantly stronger. If so is taken care that the double lighting is not so strong, that the photosensitive sensor of the camera unit used overrides The influence of this double exposure can also be detected by known Methods of image processing can be compensated.

The lighting can be done in a known manner by a so-called. Sine phase grating. In this case, an illumination light is projected onto the object or objects to be measured, which has a sinusoidal intensity profile perpendicular to the illumination direction in the triangulation plane defined by the illumination direction and the observation direction. Since the sine grid projection equals coding of the pixels to be measured and the lateral displacement of the sine grid phase for each pixel detected by the camera unit is determined in a known manner by the respective object height, false heights would be measured in the overlapping area with two different overlapping sine grid projections. In order to prevent or at least reduce possible artifacts due to the double illumination, the phase positions in the sinusoidal illumination light profiles of mutually adjacent sensor modules can be shifted by approximately 230 degrees. In this case, another si is created in the overlap area Nusiform intensity modulation with approximately the same amplitude as the two original sinusoidal intensity profiles. In the case of a flat measurement object of negligible magnitude, this sinusoidal intensity modulation would have a phase difference of approximately 65 degrees to the original sinusoidal intensity profiles.

in the height image is indeed in the overlap area the two adjacent sine intensity grids a zero shift the height measurement arise. However, this zero offset may be via image processing methods taken into account in the image calculation and be eliminated.

It It is noted that the picture-taking camera through the new in the overlap area resulting sine intensity modulation with a heightened Offset and raised illuminance especially with a strong reflectivity of the objects to be measured slightly overdriven can be. Therefore, it may be advantageous, the phase angle of the resulting sine intensity modulation within the usual not so big overlap area not for calculating the object height (s) consulted.

It it is further noted that for the described phase triangulation preferably four sine-phase positions or the height-induced displacement be used by four different phase grating lights can. This is advantageous because the corresponding computational algorithm for four different Phasing significantly less complex and rake is expensive as for example only three phases. In the typically relatively small overlap area however, it is largely negligible in terms of overall computational effort, if a complicated algorithm for height calculation required is.

According to one another embodiment of the Invention, the sensor device additionally comprises a trigger device which is coupled to the sensor modules and set up in this way is that immediately adjacent sensor modules in time offset for one altitude measurement each can be activated.

The described triggering device can be particularly advantageous and elegant way the above described problems of height evaluation within overlapping areas remedy. It can in a one-dimensional array of sensor modules, for example the sensor modules arranged at odd positions of the array at a first time and at even positions of the array arranged sensor modules simultaneously to a different second time to be activated. Of course, any are Other activation sequences conceivable, provided that it is ensured that the overlapping areas between two adjacent sensor modules not at the same time both adjacent sensor modules are measured.

According to one another embodiment of the Invention has the first sensor module and / or the second sensor module additionally another lighting unit, which is set up to illuminate an object to be measured under a further direction of illumination. Of course The at least one further sensor module can also be a further lighting unit exhibit.

Prefers are the illumination direction of the lighting unit and the others Lighting direction of the other lighting unit Be different. By using different lighting directions can advantageously eliminates shadowing effects or at least reduced and also completely surveyed objects with a large height extent become.

shadowing can for example, by means of two consecutively or sequentially performed recordings be calculated out. Through the two separate shots under each one incident from a different direction lighting of the measurement object (s) Shades arising on different sides of the object or objects each illuminated by a lighting from the other side become.

According to one another embodiment of the Invention has the first, the second and / or the further sensor module a line camera on. This means that the sensor modules of the each described typically a triangulation sensor can capture relatively short line of light. The line scan camera is thereby oriented perpendicular to the corresponding triangulation plane.

For a full three-dimensional Surveying the surface One or more measurement objects can then have a relative movement between them described triangulation sensor and the one or more measuring objects carried out become. This relative movement is at least proportionally perpendicular both to the triangulation level and to the orientation of the Line scan camera or line scan cameras.

According to one another embodiment of the Invention has the first, the second and / or the further sensor module a surface camera on. Such a z. B. have a two-dimensional CCD as a light receiver.

By the use of area cameras can with the corresponding sensor modules in each case a two-dimensional Image of at least one specific subarea of an electronic circuit substrate be recorded. Due to the triangulation measurements made by the sensor modules can the pictures also height information of the individual pixels, so that in this way three-dimensional Information can be captured (in this case, for example, these are three-dimensional images).

The individual pictures can then by appropriate image evaluation method to a two- or Three-dimensional overall picture are joined together. When joining can a so-called "stitching" method used be, in which the individual images or sub-images so spatially to each other be arranged that the mutually facing edge regions of in the overall picture of adjacent images one possible big match exhibit. To achieve one as possible great agreement can use two-dimensional and / or three-dimensional image data resorted become.

The "stitching" can be done along two Spatial directions take place. In the case of a three-dimensional survey an electronic circuit substrate, which by means of a Transport path relative to the described sensor device is moved along a transport direction, the joining or the stitching perpendicular and / or parallel to the transport direction respectively.

According to one Another aspect of the invention is a system for manufacturing electronic Modules described. The described system comprises (a) a Mounting device for loading of component carriers with electronic components, and (b) an automatic optical Inspection device for three-dimensional measurement of Bauelementeträ ger. The Optical inspection device in turn has a sensor device of the type described above.

the described manufacturing system is based on the finding that the above-mentioned sensor device in an advantageous manner with a placement device combined and thus the process reliability in the production of electronic assemblies can be improved. The inspection device can with respect to the placement device be arranged on the input side or output side. Also the use of two inspection devices is possible, with respect to the placement device a first inspection device on the input side and a second Inspection device can be arranged on the output side.

at an input-side arrangement, for example, the volumes of solder paste orders be measured, which in a known manner before the placement of the component support be applied for example by means of a screen printing process. If a faulty solder paste application is detected, the relevant component support from the placement process removed and thus early the production of a faulty module can be avoided.

at an output-side arrangement can advantageously the positions and also the heights the on a component carrier patched electronic components are measured. By a height information determined by the above-described sensor device a component can information about determines the type of each component and so usually a correct assembly be verified.

in the Case of a misadjustment The module in question may be prior to fixing the module for example by soldering the components by means of a reflow oven, if necessary by an offset a component towards a corrected position or by a reassembly a component to be repaired. In any case, however, faulty assemblies can reliable be removed from the manufacturing process. The reliability in the production of electronic components can thus be increased.

It It is pointed out that to solve the measuring task "Position measurement of components relative to a desired position "the usual referencing to the respective component carrier changed passport marks changed can be. In a known method for position determination that is a moveable camera used by means of one or more Image taken the stocked Components together with registration marks applied at defined locations can measure together or in succession. Such pass marks become common also referred to as so-called fiducials.

Since it may happen in the modular sensor device described in this application that not in every image acquisition of a sensor module a fiducial mark for position referencing is available, the known CAD data of each module, which data a description of the components and their positions contained relative to registration marks, placed on the sensor image using known methods of image processing and adapted in his position or fit. The basic assumption is that the components in their entirety have only a small syste have a matic offset. The positional deviations of individual components located within the scope of the statistical deviations can thereby be reliably determined. If systematic deviations should be present over an entire printed circuit board, these can be determined via those image recordings in which additionally a registration mark is present.

The described replacement of the known referencing to registration marks by an adaptation of the three-dimensional determined by the sensor device Measurement data on previously known CAD data has the advantage that a precise Positioning of the component carrier to be measured by the transport system or the conveyor belt is not required. This allows the Position measurement even without the use of customary very expensive precision standards are performed.

According to one embodiment According to the invention, the system additionally has a transport path for transporting the component carrier between the placement device and the inspection device.

The Inspection device with the above-described sensor device can be stationary over the Be arranged transport route. The transport route can as Transport or conveyor belt be educated. The to be equipped or the already populated component support can then scanned by a suitable movement of the conveyor belt and be measured three-dimensionally.

at the stationary one Arrangement of the inspection device relative to a conveyor belt It makes sense, as described above, the individual sensor modules the modular sensor device each equipped with a line scan camera. If the sensor line of the line scan camera is perpendicular to the transport direction The conveyor belt is oriented by the individual Sensor modules generated light lines by a suitable signal processing be assembled into a total line of light that extends across the entire width of the conveyor belt extends. With that you can the conveyor belt relative to the stationary inspection device moving objects completely by a successive line-shaped Detection of contour lines three-dimensional be recorded.

There a conveyor belt in the production of electronic assemblies especially in the area of the so-called Surface Mount Technology (SMT) used by default the sensor device described above can be advantageous Way for most production processes in the field of electronics manufacturing be used. Due to the modular design of the sensor device can the width of the same without any great effort each to the Width of the conveyor belt or to the width of the printed circuit boards to be tested be adjusted.

According to one Another aspect of the invention is a method for three-dimensional Measuring objects according to the principle of triangulation. The specified method is particularly suitable for the three-dimensional Measuring of applied on an electronic circuit substrate Components. The method includes using a sensor device of the type described above for three-dimensional measuring of Objects.

the The method is based on the finding that by a suitable combination of the results of triangulation measurements, that of the individual sensor modules of the sensor device described above be provided, a big one spatial Area also completely can be measured if each individual triangulation module respectively can cover only a comparatively small area. For the used Sensor device can be advantageously on in the recent years rapid development of camera technology can be resorted to led to has that, for example, for inexpensive digital cameras have been developed camera sensors that Already at a very low cost allow excellent image quality.

According to one embodiment The invention is (a) of different sensor modules of the sensor device in each case an at least two-dimensional image, for. B. with one each Area camera, and (b) the different images become one Total picture joined together, that the mutually facing edge portions of in the overall picture adjacent images have the greatest possible match.

The put together of the individual partial images to a two- or three-dimensional overall picture also referred to as a so-called "stitching". It can known algorithms for the appropriate joining of the individual partial images used become. Under a three-dimensional "stitching" is understood in this context, that each with a two-dimensional image and the height information of at least some pixels of the respective image at the Assessment of a possible great agreement considered becomes.

To join together sub-pictures, the be detected by different sensor modules in a given spatial position of the objects to be measured, z. For example, at the beginning of a measurement series, a one-time "calibration stitching measurement" can be carried out.For a defined spatial arrangement of the sensor modules, the partial images captured by these sensor modules can be joined together on the basis of the determined reference data in the further course of this measurement series "Stitching procedure" each time to go through again.

in the Trap one along a transport direction relative to the sensor device moved and to be measured object, the described "stitching" can also be used to join partial images together the by a sensor module of adjacent to the transport direction Subareas of the object were recorded. In particular, can this can be used to advantage if no or if only inaccurate data regarding the movement of the circuit substrate are present. This has the advantage that a meaningful Three-dimensional overall picture can be determined even if the corresponding transport route does not have accurate motion control and / or if a detection of the transport movement is not or only very inaccurate he follows. This can mean that the margins of the individual Partial images also without any prior knowledge in a suitable manner to each other together can be. This advantage comes especially when using surface cameras to image capture for carrying, since the methods described here then no longer have procedural steps that require an accurate determination make the transport movement of the object to be measured required.

In However, in this context, it should be noted that the Of course also joining If applicable, the transaction data of the DUTs are taken into account can be.

• – Aufnehmen von zumindest einem ersten und einem zweiten zumindest zweidimensionalen Bild mittels des Sensormoduls, wobei das erste Bild und das zweite Bild unterschiedliche aber einander angrenzende Teilbereiche des zu vermessenden Objekts zeigen,
• – Aneinanderfügen des zumindest ersten und zweiten Bildes zu einem Gesamtbild, so dass die einander zugewandten Randbereiche von in dem Gesamtbild aneinander angrenzenden Bildern eine möglichst große Übereinstimmung aufweisen.

It should also be pointed out at this point that joining can take place at least along the transport direction even when the sensor device has only one sensor module. In this case it is then a
Method for three-dimensionally measuring objects according to the principle of triangulation, in particular for three-dimensionally measuring components applied to an electronic circuit substrate, using a sensor module having a lighting unit and a camera unit,
wherein the lighting unit is adapted to illuminate an object to be measured under a lighting direction and
wherein the camera unit is configured to detect the object to be measured under an observation direction including a non-zero triangulation angle together with the illumination direction, comprising the method

• Receiving at least a first and a second at least two-dimensional image by means of the sensor module, wherein the first image and the second image show different but adjacent subareas of the object to be measured,
• - Joining the at least first and second image to a total image, so that the mutually facing edge regions of in the overall image adjacent images have the greatest possible match.

The both pictures can while spatially offset along a transport direction of the measurement object. In particular, you can the two images spatially offset only along this transport direction be.

This means that the areas covered by the images in the Transport direction are offset from each other. In the second mentioned Case ("only along this transport direction offset "), the sub-area have no Offset perpendicular to this transport direction.

This has the advantage that only the image to be measured Object or the objects to be measured relative to a stationary at the corresponding Transport path arranged sensor module must be moved. A additional Movement of the sensor module is not required.

The The above-mentioned method can continue according to the present Description and the present claims be configured.

• • ein Grundelement (233), und
• • ein an dem Grundelement (233) angebrachtes erstes Sensormodul (240a),

wobei das erste Sensormodul (240a) jeweils eine Beleuchtungseinheit (360) und eine Kameraeinheit (344) aufweist,
wobei die Beleuchtungseinheit (360) eingerichtet ist zum Beleuchten eines zu vermessendes Objekts (290, 390) unter einer Beleuchtungsrichtung und
wobei die Kameraeinheit (344) eingerichtet ist zum Erfassen des zu vermessenden Objekts (290, 390) unter einer Beobachtungsrichtung, die zusammen mit der Beleuchtungsrichtung einen von Null verschiedenen Triangulationswinkel einschließt, wobei weiterhin
die Vorrichtung eine Steuereinrichtung umfasst, die zur Durchführung eines der in den vorhergehenden Abschnitten beschriebenen Verfahrens ausgebildet ist.The above object is also achieved by a device sensor device for the three-dimensional measurement of objects ( 290 ) according to the principle of triangulation, in particular for the three-dimensional measurement of on an electronic circuit substrate ( 122 ) applied components, the sensor device ( 130 . 230 )

• • a basic element ( 233 ), and
• • one at the basic element ( 233 ) mounted first sensor module ( 240a )

wherein the first sensor module ( 240a ) each a lighting unit ( 360 ) and a camera unit ( 344 ) having,
the lighting unit ( 360 ) is arranged to illuminate an object to be measured ( 290 . 390 ) under a lighting direction and
the camera unit ( 344 ) is arranged for detecting the object to be measured ( 290 . 390 ) under an observation direction including a non-zero triangulation angle together with the illumination direction
the device comprises a control device which is designed to carry out one of the methods described in the preceding sections.

there For example, the device may except the first sensor module no further analogous to the first sensor module configured sensor modules exhibit.

These Device can also according to the present Description and the present claims further be configured.

According to one another embodiment of the Invention, the three-dimensional surveying of the objects takes place the basis of a phase triangulation. In the phase triangulation becomes an illumination light with a sinusoidal intensity profile projected onto the test object. The height extension of the test object causes in a known manner with an oblique illumination and / or a bevel Detection of the object to be measured a lateral displacement Δx the phase position of the sine grid. By for every pixel for different projected phase positions measured the intensity , the phase and thus the spatial coordinates can be determined precisely become. With the phase shift Φ can be the height of the DUT with the above formula (3) calculate.

The Using the described phase triangulation has the advantage that the elevation values of to be detected objects can be determined particularly accurately. In addition, can for evaluating the captured by the camera unit images on known Algorithms are used to analyze the corresponding measurement data become.

According to one another embodiment of the Invention is used for three-dimensional surveying of objects at least used a calibration table, which for different distances between a Object and a lens of the respective sensor module one each Magnification scale contains.

The Using a calibration table has the advantage that the individual Sensor modules can be equipped with a simple look, which in contrast to known and very expensive telecentric lenses have a with the distance object to lens variable magnification. This means that advantageously on expensive telecentric Lenses can be dispensed with. The variable caused thereby magnification or the resulting visually distorted image of the simple Objects can be considered by a consideration the values contained in the calibration table are compensated.

• (a) Für die einzelnen Sensormodule können preiswerte optische, elektronische und/oder optoelektronische Komponenten verwendet werden. Insbesondere sind keine telezentrischen Optiken erforderlich.
• (b) Durch die parallele Verwendung von mehreren Sensormodulen mit jeweils preiswerten Standardkomponenten kann die gesamte Sensorvorrichtung auf besonders preiswerte Weise hergestellt werden. Ein aufwendiges Layout mit einem (oder mehreren) großflächigen Kamerasensor ist nicht erforderlich.
• (c) Durch ein geeignetes Aneinanderfügen von verschiedenen Teilbildern kann im Falle von relativ zu der Sensorvorrichtung bewegten und zu vermessenden Messobjekten auch dann ein genaues Höhenprofil bestimmt werden, wenn für die Bewegung des oder der Messobjekte keine oder nur ungenaue Bewegungsdaten vorliegen. Dieser Vorteil kommt beim Verwenden von einer oder mehreren Flächenkameras besonders zum tragen.

The sensor device described in this application and the method described for the three-dimensional measurement of objects according to the principle of triangulation, in particular for the three-dimensional measurement of components applied to an electronic circuit substrate, may, depending on the design, have one or more of the following advantages, for example:

• (a) inexpensive optical, electronic and / or optoelectronic components can be used for the individual sensor modules. In particular, no telecentric optics are required.
• (b) Through the parallel use of multiple sensor modules, each with inexpensive standard components, the entire sensor device can be manufactured in a particularly inexpensive manner. An elaborate layout with one (or more) large-area camera sensor is not required.
• (c) By a suitable joining together of different partial images, in the case of measured objects moved and to be measured relative to the sensor device, an exact height profile can be determined even if there is no or only imprecise movement data for the movement of the measurement object or objects. This advantage is particularly useful when using one or more surface cameras.

Further Advantages and features of the present invention will become apparent the following exemplary description of presently preferred embodiments. The individual figures of the drawing of this application are merely to be regarded as schematic and not to scale.

1 shows a manufacturing system for electronic assemblies, which has a placement device and an optical inspection device for three-dimensional measurement of equipped with electronic components component carriers.

2 shows a sensor device with four arranged in a linear array sensor modules, which are each arranged for three-dimensional measurement of electronic components based on triangulation.

3 shows a cross-sectional view of a sensor module, which has a camera unit and a lighting unit.

4 shows in a cross-sectional representation of a sensor module, which has a camera unit and two lighting units.

At It should be noted that in the drawing the Reference signs of identical or corresponding components only in its first digit and / or by an appended letter differ.

This in 1 shown manufacturing system 100 for electronic assemblies has a placement device or a placement 110 and an optical inspection device. The placement machine 110 is used in a known manner for equipping designed as circuit boards component carriers 122 with in 1 not shown electronic components used. The optical inspection device 130 , which in the context of this application also as a sensor device 130 is designated, serves for the three-dimensional measurement of the assembled component carrier 122 ,

The placement device 110 has a chassis 112 on which a stationary support arm 114 is appropriate. On the stationary support arm 114 There are two extending along an x-direction stationary linear guides, wherein in the perspective view of 1 only a front stationary linear guides 114a can be seen. At the stationary linear guides 114a is in each case a transversely movable carrier arm which can be moved along the x-direction and extends along a y-direction 116 appropriate. At the two support arms 116 are located along the y-direction extending linear guides, wherein in 1 only a linear guide 116a can be seen. Along the two linear guides 116a is each a placement head 118 displaceable along the y-direction. By a suitable superposition of a first movement along the x-direction and a second movement along the y-direction, the Bestückkopfe 118 be moved to any position within a two-dimensional range of motion.

The assembly of a component carrier 122 takes place in a known manner (a) by picking up the components of a component feeder, not shown by the placement 118 , (b) by a transport of the picked components in a placement area above a transport route 120 and (c) placing the components at predetermined locations on the transport path 120 located component carrier.

According to the embodiment shown here, the component carrier 122 after a complete or at least partial loading along the transport route 120 removed from the placement area and slowly below the inspection device 130 through a detection area of the inspection device 130 hazards. This is the populated component carrier 122 at a plurality of different y-positions along a line of light extending in the x-direction 131 measure and the height values of each pixel of the light line 131 recorded. The higher values recorded at different y-positions are then converted into a complete three-dimensional image of the assembled component carrier in an image processing unit (not shown) 122 put together.

The light line 131 is composed in a manner not shown of several individual juxtaposed light lines. The individual comparatively short light lines are each from a sensor module 140 generated, which, as described below with reference to 2 to 4 explained, is also responsible for the height measurement of lying in the respective light line surface pixels.

How out 1 also seen, is a holding device 132 provided with the inspection device 130 in a fixed position above the transport route 120 can be arranged. According to the embodiment shown here is the modular sensor device 130 in relation to the placement device 100 arranged on the output side.

As the holding device 132 not firmly on the chassis 112 anchored, the sensor device could 130 also on the input side over the transport route 120 to be ordered. In this case, for example, the solder paste volumes could be measured and in the case of a too low or too extensive application of a solder paste on at least one connection point, the corresponding component carrier 120 be eliminated from the assembly process.

2 shows the sensor device 130 , which now with the reference numeral 230 is provided, in a schematic cross-sectional view parallel to a plane which is spanned by the x-direction and the z-direction. These directions agree with the corresponding in 1 marked directions. For clarity, is in 2 the inspection device or the sensor device only with four sensor modules, a first sensor module 240a , a second sensor module 240b , and two other sensor modules 240c and 240d shown. The sensor modules 240a . 240b . 240c and 240d form there in a linear array 235 which extends parallel to the x-direction.

The sensor modules 240a . 240b . 240c and 240d each have a housing 242 on, in which a camera unit 244 with an associated optics 246 and one in 2 not shown lighting unit. The housing 242 are on a basic element designed as a base plate 233 appropriate. The camera unit 244 has a camera sensor designed as a line sensor 245 on. The line sensor 244 is oriented parallel to the x-direction.

Two adjacent sensor modules 240a and 240b . 240b and 240c and 240c and 240d are by means of an adjusting device 243 connected to the relative spatial position between the corresponding housings 242 can be set exactly. This allows the fields of vision of the sensor modules 240a . 240b . 240c and 240d in an object plane 250 be aligned relative to each other such that the means of the sensor device 230 a gap-free line of measurement is created along the x-direction over the entire object plane 250 extends. This ensures that all are in the object plane 250 located measuring objects 290 can be measured.

In the embodiment shown here, the objects are electronic components 290 which were placed on a component carrier. In 2 Therefore, the upper side of the device carrier coincides with the object plane 250 together.

How out 2 can be seen form the fields of view in the embodiment shown here 255 of two adjacent sensor modules 240a and 240b . 240b and 240c and 240c and 240d each one overlap 252 , This will ensure that the individual sensor modules 240a . 240b . 240c and 240d form a complete or continuous line of light. Since the overlapping areas are each illuminated by two lighting units, this will set a higher illumination intensity. When using sinusoidal illumination gratings, a superposition of two spatially sinusoidal intensity modulations will set to a new sinusoidal intensity modulation.

However, these effects can be obtained by an evaluation of the measured and by the height expansion of the measurement objects 290 caused displacements of the projection patterns are compensated.

According to the exemplary embodiment shown here, these effects caused by a double illumination can be avoided from the outset by the illumination units of two adjacent sensor modules 240a and 240b . 240b and 240c and 240c and 240d be activated at different times. This will ensure that the overlap areas 252 be illuminated twice at any time. Preferably, such a temporal separation in the illumination can take place in that a trigger device 248 , which via a multi-pole trigger line 249 with the sensor modules 240a . 240b . 240c and 240d is coupled, at a first time, the sensor modules 240a and 240c and at a different second time, the sensor modules 240b and 240d to be activated.

3 shows in a cross-sectional view parallel to the in the 1 and 2 defined y-direction and z-direction a single sensor module 340 , In a housing 342 there is a camera unit 344 with a line sensor 345 and a lighting unit 360 , An optic 346 , which the camera unit 344 is assigned to the mapping of the in a visual field 355 an object plane 350 located and the lighting unit 360 illuminated measuring objects 390 on the line sensor 345 , An optic 366 , which of the lighting unit 360 is assigned, the projection is one of a light source 362 generated illumination light on the visual field 355 , In the light source 362 a not explicitly shown optical element is integrated, which imparts a spatial intensity modulation to the primary light beam emitted by a light-emitting element. The intensity modulation can be, for example, a sinusoidal phase grating, which in a known manner according to the principle of triangulation for the height determination of the measurement objects 390 is used.

According to the embodiment shown here are the optics 346 and 366 simple lenses. In particular, it is the optics 346 and 366 not about telecentric optics. In contrast to telecentric optics, the magnification of the optical image of simple lenses depends on the distance between the lens and the object. This dependency can be used in the evaluation of measured by the height extent of the measurement objects 390 caused displacements of the projection patterns are compensated. This compensation can be done for example by the use of calibration tables, which each contain a magnification scale for different distances between object and optics. This can be taken into account for the purpose of a precise height measurement in the subsequent determination of the 3D height profiles.

4 shows in a cross-sectional view a sensor module 440 according to a further embodiment of the invention. The cross-sectional plane is also parallel to the in the 1 and 2 defined y-direction and z-direction. The sensor module 440 is different from the one in 3 illustrated sensor module 340 merely by being in a housing 442 next to a first lighting unit 460 another lighting unit 470 located. The further lighting unit 470 which are the measurement objects 490 at a different illumination angle than the first illumination unit 460 illuminated, has the same structure as the lighting unit 460 , The lighting unit 460 respectively. 470 Thus, each has a light source with optical element 462 respectively. 472 and an optic 466 respectively. 476 on. The camera unit 444 has the same as the camera unit 344 a line sensor 445 and an optic 446 on.

The use of the further lighting unit 470 has the advantage that with different lighting directions shadowing effects can be eliminated or at least reduced. Shading effects can be calculated out, for example, by means of two consecutively or sequentially performed images. By the two separate images under each incident from another direction illumination of the object or objects can be illuminated on different sides of the object or objects resulting shadowing each by a lighting from the other side.

• • Die Sensorvorrichtung kann auf einfache Weise in bereits bestehende Bestückvorrichtungen integriert bzw. mit bestehenden Bestückvorrichtungen kombiniert werden.
• • Die Sensorvorrichtung erlaubt im Vergleich zu bekannten optischen 3D-Messsystemen eine sehr schnelle Vermessung, so dass durch eine einer Bestückung nachgeschaltete Automatische Optische Inspektion die volle Bestückleistung bekannter Hochgeschwindigkeitsbestückautomaten beibehalten werden kann. Dies gilt auch für eine Online-3D Vermessung von Lotpastenaufträgen, welche vor einer Bestückung durchgeführt wird.
• • Die Sensorvorrichtung kann stationär angebracht werden.

Apart from the advantages described above in the course of this application, the sensor device has the following further advantages:

• The sensor device can be easily integrated into existing placement devices or combined with existing placement devices.
• • The sensor device allows in comparison to known optical 3D measuring systems a very fast measurement, so that can be maintained by a placement downstream automatic optical inspection, the full placement of known Hochgeschwindigkeitsbestückautomaten. This also applies to an online 3D measurement of solder paste orders, which is carried out before assembly.
• • The sensor device can be mounted stationary.

A Therefore, 3D surveying can be done without the use of moving components carried out become. Only at elongated Objects such as device carriers is a one-dimensional Movement of the same, for example by means of a conveyor belt or a transport route required.

It It should be noted that the embodiments described herein only a limited Choice of possible variants represent the invention. So it is possible the characteristics of individual embodiments suitably combine with each other, so for the skilled person with the embodiments explicitly shown here a variety of different embodiments are to be regarded as obviously disclosed.

100

manufacturing system

110

Mounting device / placement machine

112

chassis

114

stationary support arm

114a

stationary linear guide

116

crosswise standing support arm

116a

linear guide

118

placement

120

transport distance

122

Component carrier / PCB

130

Inspection device / sensor device

131

Lichtzeile

132

holder

140

sensor module

230

Inspection device / sensor device

233

Base member / base

235

array

240a

sensor module

240b

sensor module

240c

sensor module

240d

sensor module

242

casing

243

adjusting

244

camera unit

245

Camera Sensor / line sensor

246

optics

248

trigger device

249

trigger line

250

object level

252

overlap area

255

Facial field

290

Measurement object / electronic module

340

sensor module

342

casing

344

camera unit

345

Camera Sensor / line sensor

346

optics

355

Facial field

360

lighting unit

362

light source with optical element

366

optics

390

Measurement object / electronic module

440

sensor module

442

casing

444

camera unit

445

Camera Sensor / line sensor

446

optics

460

lighting unit

462

light source with optical element

466

optics

470

Further lighting unit

472

light source with optical element

476

optics

490

Measurement object / electronic module

Claims (15)

Sensor device for the three-dimensional measurement of objects ( 290 ) according to the principle of triangulation, in particular for the three-dimensional measurement of on an electronic circuit substrate ( 122 ) applied components, the sensor device ( 130 . 230 ) comprising • a basic element ( 233 ), • one at the basic element ( 233 ) mounted first sensor module ( 240a ) and • one at the basic element ( 233 ) mounted second sensor module ( 240b ), wherein the first sensor module ( 240a ) and the second sensor module ( 240b ) each a lighting unit ( 360 ) and a camera unit ( 344 ), wherein the lighting unit ( 360 ) is arranged for illuminating an object to be measured ( 290 . 390 ) under a direction of illumination and wherein the camera unit ( 344 ) is arranged for detecting the object to be measured ( 290 . 390 ) under an observation direction including a non-zero triangulation angle together with the illumination direction. Sensor device according to claim 1, additionally comprising • at least one further sensor module ( 240c . 240d ), which is also a lighting unit ( 360 ) for illuminating an object to be measured ( 290 . 390 ) under a lighting direction and a camera unit ( 344 ) for detecting the object to be measured ( 290 . 390 ) under a direction of observation different from the direction of illumination, wherein the first sensor element ( 240a ), the second sensor element ( 240b ) and the at least one further sensor element ( 240c . 240d ) a one-dimensional or a two-dimensional array ( 235 ) form. Sensor device according to one of Claims 1 to 2, in which the visual fields ( 255 . 355 ) of the sensor modules ( 240a . 240b . 240c . 240d . 340 ) on an object level ( 250 ) are each at least as large as the lateral dimensions of the respective sensor modules ( 240a . 240b . 240c . 240d . 340 ). Sensor device according to one of claims 1 to 3, additionally comprising at least one mechanical adjusting device ( 243 ) arranged such that the relative spatial spacing between different sensor modules ( 240a . 240b . 240c . 240d ) is adjustable. Sensor device according to one of claims 1 to 4, wherein the individual sensor modules ( 240a . 240b . 240c . 240d ) are arranged such that the visual fields ( 255 ) of two mutually directly adjacent sensor modules ( 240a . 240b ; 240b . 240c ; 240c . 240d ) at least one predetermined overlap ( 252 ) exhibit. Sensor device according to one of claims 1 to 5, additionally comprising • a trigger device ( 248 ), which with the sensor modules ( 240a . 240b . 240c . 240d ) and is arranged such that immediately adjacent sensor modules ( 240a . 240b ; 240b . 240c ; 240c . 240d ) offset in time for each height measurement can be activated. Sensor device according to one of claims 1 to 6, wherein the first sensor module ( 240a . 340 ) and / or the second sensor module ( 240b . 340 ) additionally a further lighting unit ( 470 ) which is set up to illuminate an object to be measured ( 490 ) under a further direction of illumination. Sensor device according to one of claims 1 to 7, wherein the first, the second and / or the further sensor module ( 240a . 240b . 240c . 240d . 340 . 440 ) a line camera ( 245 . 345 . 445 ) having. Sensor device according to one of claims 1 to 7, wherein the first, the second and / or the further sensor module ( 240a . 240b . 240c . 240d . 340 . 440 ) an area camera ( 245 . 345 . 445 ) having. System for manufacturing electronic assemblies, the system ( 100 ) comprising • a placement device ( 110 ) for equipping component carriers ( 122 ) with electronic components, and • an automatic optical inspection device ( 130 ) for the three-dimensional measurement of the component carrier ( 122 ), wherein the inspection device comprises a sensor device ( 130 ) according to one of claims 1 to 9. System according to claim 10, additionally comprising • a transport route ( 120 ) for transporting the component carrier between the mounting device ( 110 ) and the inspection device ( 130 ). Method for the three-dimensional measurement of objects ( 290 ) according to the principle of triangulation, in particular for the three-dimensional measurement of on an electronic circuit substrate ( 122 ) applied components ( 290 ), having the method • using a sensor device ( 130 . 230 ) according to one of claims 1 to 9 for the three-dimensional measurement of the objects ( 290 ). Method according to claim 11, wherein • of different sensor modules ( 240a . 240b ) of the sensor device ( 130 . 230 ) is taken in each case an at least two-dimensional image and • the various images are joined together to form an overall image, that the mutually facing edge regions of in the overall image adjacent images have the greatest possible agreement. Method according to one of claims 12 to 13, wherein the three-dimensional measuring of the objects ( 290 ) on the basis of a phase triangulation. Method according to one of claims 12 to 14, wherein for the three-dimensional measurement of the objects ( 290 ) at least one calibration table is used, which for different distances between an object ( 290 ) and a lens ( 246 ) of the respective sensor module ( 240a . 240b . 240c . 240d ) each contains a magnification scale.