GB2466362A

GB2466362A - Irradiation device

Info

Publication number: GB2466362A
Application number: GB0921577A
Authority: GB
Inventors: Rudolf Merkel; Uwe Zimmermann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2008-12-17
Filing date: 2009-12-09
Publication date: 2010-06-23
Anticipated expiration: 2029-12-09
Also published as: GB2466362B; DE102008054801A1; FR2939908A1; GB0921577D0

Abstract

An irradiation device 1 has a working radiation source 3 for irradiating an object 2 by means of a working, or illuminating, radiation 5. A deflection device 6 is arranged as an active beam guidance and/or beam shaping device for the working radiation 5. A measuring radiation source 4 outputs a measuring radiation 12 onto the object. A receiving device 13 receives the measuring radiation 12 returned from the object. The measuring radiation 12 is guided via the deflection device 6. The device may be embodied as as an automatically repositioning spotlight on a stage that uses the measuring beam to follow a moving object e.g. a performer.

Description

Description Title

Irradiation device and method for irradiating an object

Prior art

The invention relates to an irradiation device, comprising a working radiation source that is realized to irradiate an object by means of a working radiation, comprising a deflection device that is realized and/or arranged as an active beam guidance and/or beam shaping device for the working radiation, comprising a measuring radiation source that is realized to output a measuring radiation that is directed and/or directable, at least for a time, onto the object, and comprising a receiving device that is realized to receive the measuring radiation returned from the object. The invention also relates to a method for irradiating an object.

Irradiation devices that guide a radiation onto an object are known in a multiplicity of embodiments and scales.

Thus, in the case of barcode lasers, irradiation devices are required to guide a laser beam over a label in a scanning manner. However, irradiation devices are also used, for example, for the purpose of selectively illuminating a performer on a stage. Further fields of application of irradiation devices are in material working, a laser beam being directed onto a workp�ece and moved on the latter for the purpose of modifying material. In the case of many applications, the irradiation device is controlled according to a fixed scheme, such as, for example, in the case of scanning a barcode label; in the case of other applications, measurement methods are used to detect the object to be irradiated, the radiation of the irradiation device being positioned or controlled in dependence on the detected object.

Disclosure of the invention

Proposed within the scope of the invention are an irradiation device, having the features of Claim 1, and a method for irradiating an object, having the features of Claim 11. Preferred or advantageous embodiments of the invention are given by the dependent claims, the following

description and the appended figures.

Presented as invention is an irradiation device, which comprises a working radiation source realized for irradiating an object by means of a working radiation. In the most general implementation of the invention, the working radiation can be of any wavelength, have any wavelength range, any intensity or energy, and thus be any kind of radiation, particularly optical radiation.

Preferably, the working radiation is realized as a directed radiation.

The irradiation device comprises a deflection device, the deflection device being realized as an active beam guidance and/or beam shaping device for the working radiation and/or arranged accordingly in the irradiation device. As a result of being implemented as an active unit, the deflection device is realized to be controllable by open-loop and/or closed loop control, particularly via open-loop and/or closed-loop control signals, in order to alter the course of the beam of the working radiation. On the one hand, the deflection device can alter the beam guidance, thus, in particular, the beam direction; alternatively, or in addition, the deflection device can shape the working radiation, the shaping being able to affect, in particular, the intensity and/or the phase of the working radiation.

The irradiation device comprises, as a further component, a measuring radiation source that renders possible the output of a measuring radiation, particularly an optical measuring radiation, that is directed and/or directable, at least for a time, onto the object. The measuring radiation, particularly under certain operating conditions, enables the object to be sensed metrologically.

For receiving the measuring radiation returned, in particular reflected, from the object, the irradiation device has a receiving device, on the output side of which there is connected, optionally, an evaluation device that evaluates the returned and received measuring radiation.

it is proposed, within the scope of the invention, that the measuring radiation undergo guidance and/or be guided via the deflection device. The irradiation device is therefore realized to guide the working radiation and the measuring radiation simultaneously and/or successively via the common deflection device and, in particular, via common deflection elements of the deflection device. Preferably, the returned and received measuring radiation is likewise guided via the deflection device.

The irradiation device according to the invention has the advantage that the deflection device can be used both for the working radiation and for the measuring radiation.

This results, firstly, in a reduction of the number of optical elements for the deflection of the radiations, since the existing elements are used twice. A further advantage consists in that the working radiation and the measuring radiation -insofar as both are activated -are synchronised optically/mechanically to one another and are therefore always deflected together.

In the case of a preferred development of the invention, the working radiation and measuring radiation are guided coaxially, particularly after the deflection device. For example, the joint guidance of the radiation paths of the working radiation and measuring radiation before the deflection device can be effected by means of a beam splitter. In this way, the beam adjustment of the measuring radiation and working radiation can be effected in the beam course before the deflection device.

In the case of a preferred realization of the invention, the receiving device is realized to detect the existence and/or the distance of the object and/or the reflectivity of the object. In the case of detection of existence, it is determined whether the object is present in the beam course of the measuring radiation, but there is no measurement of distance. In the case of detection of the distance, on the other hand, the distance from a reference point, such as, for example, the deflection device, to the object is determined. Particularly preferably, the receiving device realizes a delay-time measurement and/or a phase measurement for the purpose of measuring the distance. The measuring radiation source, deflection device and receiving device constitute, in particular, a sensor system for sensing of the surroundings, particularly for sensing of the surroundings in 3D, which system can record a 2D or 3D image of the object, in particular a 2D scan with depth information. The detection of the reflectivity can be used, for example, to sense a line marking on the object, for the purpose of subsequently guiding the working radiation along the line marking.

In the case of a development of the invention that is preferred in respect of design, the deflection device is realized as a reflective unit, which preferably achieves the beam guidance or beam shaping exclusively through reflection elements. This structure has the advantage that differing wavelengths are at least deflected at the same angle, and chromatic distortions are minimized. In the case of other embodiments, however, it is also possible to use transmissive elements. Particularly preferably, the deflection device is realized as a scanner unit, e.g. having scanner mirrors, as an adaptive optical system, i.e. as an optical system that allows controlled alteration of the phase position of the radiations, or as a MEMS unit, i.e. a combination of mechanical elements and control elements on a base, which unit likewise enables the radiation direction and/or the phase position of the radiation to be altered.

Particularly preferably, the working radiation and/or the measuring radiation is realized as a spot-light. The radiation is preferably designated as a spot-light if this radiation has a maximum included angle of less than 200, preferably less than 10°, and particularly less than 5°.

The total included angle is measured, for example, at the half-width (FWHM threshold) . Preferably, the radiations each have a parallel beam course.

With the objective of being able to perform the measurement of the object without this being noticed or disturbed by other radiation, it is preferred if the measuring radiation is arranged in a non-visible range. For this purpose, it is possible for the measuring radiation to be located in a UV, NIR, IR or FIR range. For example, the visible waveband 400 -750 nm is left free.

In the case of a first possible embodiment of the invention, the working radiation is realized to illuminate the object. The illumination in this case is dimensioned in such a way that, in the case of a first alternative, the illuminated object is perceptible by the human eye. In the case of a second alternative, the illumination is such that the object can be recorded by an artificial sensor system, e.g. a camera.

In the case of another embodiment of the invention, the working radiation is realized, preferably as a laser, to process, particularly modify, the object. For example, the working radiation can be realized as a laser beam that makes it possible to heat the object locally by more than 00, in particular to cut, coat or fuse the object. The processing of the object can also be effected through exposure, the object being exposed, for example, by means of a UV radiation as working radiation, in order to achieve a photochemical reaction. In particular, the working radiation has a power of more than 100 watts and/or a pulse energy of more than 1 J. Preferably, the irradiation device has a control device, which preferably controls the deflection device, the working radiation source and the measuring radiation source and/or reads-out the receiving device, and which is realized to execute the following method, or the method according to Claim 11. Preferably, the control device is realized to guide the working radiation and/or the measuring radiation in a scanning and/or writing manner.

The invention also relates to a method for irradiating an object by means of the irradiation device as described previously, the object being selectively irradiated by means of the working radiation. Within the meaning of the invention, selective irradiation is understood to mean that the irradiation is limited to object regions, i.e. partial regions of the object, or to the object itself. In particular, the object regions for selective irradiation are selected by the control device on the basis of the measurement values of the receiving device.

In the case of a possible embodiment, the control device is realized to identify the object on the basis of the measurement values of the receiving device. For example, a 3D image of the object can be constructed from the measurement radiation returned from the object, and this image can be identified and/or classified in an automated manner by means of digital image processing methods.

Selective illumination of the identified object and/or of the partial regions of the object can be effected in dependence on the identification result.

In the case of a preferred development of the invention, provision is made whereby the measuring radiation and the working radiation are optionally activated either jointly or alternately. This gives various possibilities for operation of the irradiation device, which can also be used in a mixed manner: In the case of a first operating mode, the working radiation and measuring operation are always activated jointly, the measuring of the object and the irradiation of the object being effected simultaneously.

In the case of a second operating mode, the working radiation and measuring radiation are activated with a time overlap, the working radiation being activated in those spatial directions in which there are located parts of the object that are to be illuminated. The measuring radiation, on the other hand, is also activated in spatial directions in which no object is present and/or the working radiation is deactivated, such that blanking is effected.

In the case of third operating mode, the working radiation and measuring radiation are activated alternately, without a time overlap, in order to prevent interactions and interference.

Particularly preferably, the irradiation device is realized for the purpose of writing irradiation and/or scanning irradiation. Thus, for example, the irradiation device can guide the radiations, by means of the deflection device, to write line-by-line and/or in the manner of a matrix.

Further features, advantages and effects of the invention are given by the following description of a preferred exemplary embodiment of the invention, wherein: Figure 1 shows a schematic block diagram of an irradiation device as an exemplary embodiment of the invention; Figure 2 shows a schematic representation of a result matrix of the irradiation device of Figure 1.

Figure 1 shows a schematic representation of an irradiation device 1, which is realized for the selective irradiation of an object 2. The irradiation device 1 comprises a working radiation source 3, which is realized to emit working radiation of a first wavelength, and comprises a measuring radiation source 4, which is realized to emit a measuring radiation having a second wavelength, the first and the second wavelength differing from one another.

Instead of a wavelength, it may also be wavelength ranges, which are then realized in a non-overlapping manner.

The working radiation source 3 emits a working radiation 5, which can be spatially deflected via a deflection device 6.

The deflection device 6 is realized to deflect the working radiation 5 in a scanning manner, particularly in a writing and/or unblanking manner. In this way, the object 2 can be illuminated, for example, line-by-line and column-by-column. A solid-angle deflection, as shown in Figure 1, is conceivable; in the case of alternative embodiments, a parallel displacement of the working radiation 5 can also be effected.

-10 -Figure 2 shows, for example, a matrix 7 having matrix points 8, the deflection device 6 being realized to scan a radiation along lines 9 and columns 10.

Returning to Figure 1, a coupling-in element 11, particularly in the form of a beam splitter, is interposed, before the deflection device 6, in the beam path of the working radiation 5. Via the coupling-in element 11, a measuring radiation 12 of the measuring radiation source 4 is coaxially coupled into the beam path of the working radiation 5, such that the measuring radiation 12 and the working radiation 5 -insofar as both are activated simultaneously -are deflected in like manner by the deflection device 6.

The irradiation device 1 additionally comprises a receiving device 13, which is realized and/or arranged for receiving measuring radiation 12 reflected back or radiated back from the object 2.

In the exemplary embodiment represented, the receiving device 13 is realized via a second coupling-in element 14, likewise realized as a beam splitter. The measuring radiation source 4, deflection device 6 and receiving device 13 together constitute a sensor system 15 for detecting the object 2. The sensor system 15 in this case can be realized as a 2D sensor system that examines the measuring field, constituted by the matrix 7, merely for the existence of the object 2, or it can be realized as a 3D sensor system that forms three-dimensional object information following the scanning of the measurement

field, or matrix 7.

-11 -A control device 16 is used to control the irradiation device 1, which control device receives, as input quantities, the measuring signals or the further processed measuring signals of the sensor system 15, and provides, as output quantities, control signals for the deflection device 6, for the measuring radiation source 4 and for the working radiation source 3, as components of the irradiation device 1.

In terms of functioning, the measuring radiation 12 is coupled-in coaxially with the working radiation 5, both radiations scanning the matrix 7, and thus a processing field, or a measurement field, in a writing manner in the surroundings, via the deflection device 6. From the components of the measuring radiation 12 that are reflected back, which are again guided via the deflection device 6, the receiving device 13 can determine, at each matrix point 8 of the matrix 7, an item of object information: existence yes/no, or a distance value, or a reflectivity value. The control device 16 is realized to identify an object: on the basis of these measurement values, or derived measurement values, for example in that a scanned structure 17 (Figure 2) is compared with previously stored reference objects.

In the case of a first operating mode, the control device 16 can so activate the components that illumination of the object 2 by means of the working radiation and measuring radiation is effected only in the context of the structure 17 having been detected and/or identified. In this operating mode, the working radiation 5 and measuring radiation 12 are activated simultaneously, the control device 16 performing object tracking, if appropriate, such -12 -that the object 2, or the structure 17, is always illuminated, or measured, in the correct position.

In the case of a second operating mode, the matrix 7 is always scanned completely, as a measurement field, by the measuring radiation 12, the working radiation 5 in each case being activated selectively, only in the region of the identified structure 17. In the case of this operating mode, a new position of the structure 17, and therefore of the object 2, can be determined after each sweep of the matrix 7 and the object 2 can be illuminated again, in the correct position, in the next sweep.

In the case of a third operating mode, the measuring radiation 12 and the measuring radiation 5 are activated alternately, in order to prevent mutual influencing.

Possible fields of application of the irradiation device 1 are: -A selective illumination of scenarios, preferably having moving objects, e.g. on a stage, an automatically repositioned spot-light, for illuminating one of the moving objects, particularly a performer, being realizable through the irradiation device 1.

-In monitoring devices, e.g. in the case of security applications, the irradiation device 1 enables a relevant object to be detected by the sensor system 15 and selectively illuminated. As in the case of all embodiments, object tracking is possible in principle.

-13 - -In the case of other fields of application, the working radiation 5 can be realized, for example, with UV light.

-In addition to the selective illumination of an object 2, it is also possible for partial regions of the object 2 to be selectively masked-out, e.g. for the purpose of preventing the red-eye effect in the case of flash photography, through selective non-illumination of the pupils, or for special effects in the case of stage illumination.

-A possible advantage of the invention lies in its energy-saving potential, since, for example in the case of security applications, it is not necessary to illuminate an entire scenario, but only the objects classified as relevant.

-A further field of application is the use of the

irradiation device 1 for illumination of hazardous situations in the case of travel assistance systems, wherein moving objects, e.g. pedestrians on a street, can be illuminated selectively.

-Further fields of application arise in material working by means of radiation, wherein real-time control of the material working operation is rendered possible by means of the irradiation device 1. This field of application can be used advantageously in the case of inhomogeneous materials, where it is a matter of adapted intensity regulation in regions of differing effectiveness of the radiation.

-14 - -The irradiation device 1 can also be used for material working, e.g. laser engraving, on moving objects, wherein, for example, the material working becomes possible in the case of a running conveyor belt, with production ongoing.

-In the case of material working, the irradiation device 1 also allows setpoint/actual comparison of a form to be produced, in real time.

-In the case of application of material, such as, for example, in the case of a printer or in the case of deposit-welding, the irradiation device 1 can be used to check a material application online and/or in real time and, if appropriate, to adjust or control the material application.