Non-imaging concentrator unit, illumination device and inspection system
Patent Information
- Application Number
- EP2023793773
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-26
- Filing Date
- 2023-10-19
- Publication Date
- 2025-09-03
AI Technical Summary
Existing line scan inspection systems using imaging optics are inefficient in utilizing the emitted power of light sources, particularly for Lambertian radiators, as only a small portion of the light is effectively used for inspection tasks.
A non-imaging concentrator unit comprising two two-dimensional non-imaging concentrators arranged in a configuration that scatters and collects light, enhancing light concentration and efficiency by directing a high portion of the light source's power to a specific inspection area while allowing optical observation of the area.
The solution achieves a high degree of efficiency in transporting light source power to the inspection area, enabling effective illumination and observation, suitable for various inspection tasks such as circuit boards, wafers, and solar cells, with improved lighting performance and reduced light loss.
Smart Images
Figure 1.1
Abstract
Description
[0001] Non-imaging concentrator unit, lighting device and inspection system
[0002] DESCRIPTION
[0003] The invention relates to an inspection system which operates with a line scan camera, as well as a lighting device therefor.
[0004] A line-scan inspection of objects is often performed in quality assurance to analyze the objects across a wide area in a short time. Line-scan cameras are used for this purpose. These cameras are aimed at the object to be examined and capture line-by-line images of the object, for example, moving beneath the camera.
[0005] The illumination of objects that are inspected using a line scan camera has so far been carried out using imaging optics, as a distance is required between the light source and the object. The imaging optics projects a line of light onto the object, and the line scan camera observes the area of the object onto which the line of light is projected. With imaging optics, a high radiance can be achieved on the object over a small area. The disadvantage of imaging optics, however, is that only a small portion of the power emitted by the light source can be used for the inspection task. This disadvantage is particularly evident for light sources that correspond to a Lambertian radiator.
[0006] The object of the present invention is therefore to create an inspection system in which the radiated power of a light source is used more effectively, ie a higher efficiency is achieved, wherein the inspection of the object is still to be carried out with a camera.
[0007] The above object is achieved by a concentrator unit having the features of claim 1, by a lighting device having the features of claim 10 and by an inspection system having the features of claim 12.
[0008] In particular, the above object is achieved by a non-imaging concentrator unit comprising a first two-dimensional non-imaging concentrator with a first input opening and a first output opening and a second two-dimensional non-imaging concentrator with a second input opening, the cross-section of which has a first section and an adjacent second section, and a second output opening, wherein the first concentrator is arranged one behind the other in a configuration that scatters the incident light and the second concentrator is arranged one behind the other in a configuration that collects the incident light along the direction of propagation of the light, wherein the second concentrator is arranged behind the first concentrator such that the light emerging from the first output opening falls into the second input opening in the region of the first section,wherein an optical observation path, for example for a camera, runs through the second section of the second input opening and the second output opening.,
[0009] The above concentrator unit consists of two non-imaging concentrators. A non-imaging concentrator is an element of non-imaging optics (also known as illumination optics), which is used to illuminate an object. The concentrator has an input opening and an output opening for the light. The light entering the input opening from a specific angular range is deflected by internal light-deflecting devices of the concentrator (reflective surfaces or bodies transparent to the light) and passed along an optical axis to the output opening. The light then exits the concentrator at the output opening. In principle, the concentrator can be arranged in two configurations. In a light-collecting configuration, the light entering the input opening is deflected in such a way that an overall light collection results at the output opening, i.e.The light is deflected in the direction of the optical axis or the center of the light beam. In a light-scattering configuration, the light entering the concentrator's input opening is deflected in such a way that overall light scattering occurs at the output opening, i.e., the light is deflected outward, away from the optical axis or the center of the light beam.
[0010] The two non-imaging concentrators can be arranged directly one behind the other in the direction of light propagation. The light emitted by a light source enters the first input opening of the first concentrator and passes through the first concentrator and through the first output opening directly into the second input opening of the second concentrator (i.e. the first output opening forms part of the second input opening). In this exemplary embodiment, the second concentrator is arranged, for example, directly behind the first concentrator in the direction of light propagation such that the first concentrator overlaps with the second input opening in the first section of the second input opening. Alternatively, the light emerging from the first output opening can be guided into the second input opening via a light guide arranged between the first concentrator and the second concentrator.In both cases, the light is then forwarded from the second concentrator to the second exit aperture, where the light exits the concentrator unit. The exiting light illuminates a predetermined inspection area of an object located behind the second exit aperture of the second concentrator in the direction of the propagating light.
[0011] In both cases described above, where the second concentrator is arranged behind the first concentrator, the first section of the second input opening of the second concentrator is sealed off from the outside, so that no light exiting the first output opening of the first concentrator can escape from the concentrator unit, and thus this light remains in the concentrator unit. The second section of the second input opening, in contrast, is open to the outside, so that an observer (e.g., a camera) can observe the inspection area of the object via the optical observation path described in more detail below.
[0012] In the concentrator unit, the first concentrator and the second concentrator are arranged in opposite directions in the optical sense with regard to their light bundling. Furthermore, the described properties of the light bundling refer to each cross-sectional area that runs perpendicular to the transverse direction (the transverse direction corresponds to the direction of greatest extension of the line-shaped illumination). The first concentrator is arranged in a configuration that scatters the incoming light, while the second concentrator is used in a configuration that collects the incoming light. By arranging the two concentrators one behind the other along the light path (optionally with an intermediate light guide as described above), the first concentrator scatters the light incident from the light source, and the second concentrator collects the light incident from the first concentrator / reaching the second concentrator.Since further light can enter the second concentrator through the second section of the second entrance opening of the second concentrator, this light is also collected by the second concentrator.
[0013] Furthermore, with regard to the concentrator unit according to the invention, it is noteworthy that, with respect to a cross-section through the concentrator unit, the second input opening, i.e. the input opening of the second concentrator, is larger than the first output opening, i.e. the output opening of the first concentrator or a corresponding light guide. In other words, the diameter of the second input opening in the direction of the cross-section is larger than the sum of the diameter of the first output opening and the wall thickness of the first concentrator or the corresponding dimension of the light guide. The area of the second input opening that remains free due to this difference (i.e. the second section of the second input opening) forms an opening for the optical observation path described in more detail below. The first concentrator orthe light guide overlaps with the second input opening only in the first section, and the light exiting the first concentrator in this section enters the second concentrator directly or via a light guide. The second section of the second input opening, which is adjacent to the first section, forms a through opening accessible from outside the concentrator unit, which extends laterally to the path of the light coming from the first concentrator and into the interior of the second concentrator. This opening in the second section of the second input opening creates an optical observation path or route that runs through the second concentrator to the second output opening, i.e. the output opening of the second concentrator.Along this observation path, an observer, for example a camera, can observe the object which is arranged (with respect to the direction of propagation of the light) behind the second exit opening (i.e. behind the second concentrator). There, the observer can in particular observe the predetermined illuminated inspection area which is illuminated by means of the light source and the concentrator unit. The second section or the opening for the optical observation path can, for example, have a diameter of between 3 mm and 30 mm, e.g. between 5 mm and 20 mm, in the direction of the cross-section. Examples of the extent of the second section of the second entrance opening in the transverse direction (i.e. perpendicular to the cross-section) are described below. The second section of the second entrance opening can therefore, for example, be rectangular or slit-shaped.
[0014] Advantageously, the concentrator unit according to the invention therefore ensures that the light source's output is transported with very high efficiency to a desired area, namely to the inspection area of an object arranged behind the concentrator unit. Furthermore, the concentrator unit according to the invention enables the observation of this inspection area in a simple manner that is favorable for the spatial arrangement of a camera. The concentrator unit is thus suitable for use in a variety of inspection tasks, for example, for the inspection of circuit board surfaces, wafers and solar cells, glass surfaces, mirror surfaces, foils, printed products, metals, etc.
[0015] In one embodiment, the non-imaging concentrator unit is designed in a line shape such that the first input opening, the first output opening, the second input opening and the second output opening each have a corresponding gap shape extending in a transverse direction. The respective gap shape of the respective opening is characterized in that it has the greatest extent in the transverse direction, while the opening has a significantly smaller extent in a direction perpendicular to the transverse direction (i.e. the cross-section). The structure of the concentrator unit is identical in the transverse direction, i.e. all cross-sections through the concentrator unit that run perpendicular to the transverse direction are identical. For example, the extent of the openings in the transverse direction can be several centimeters to a few meters, while the openings perpendicular to this transverse direction are only a few millimeters wide.For example, the first inlet opening, the second section of the second inlet opening, and the second outlet opening have a transverse length of 200 mm to 500 mm. The first inlet opening has a dimension perpendicular to the transverse direction, e.g., of 1 mm to 12 mm, for example, of 5 mm. The second outlet opening has a dimension perpendicular to the transverse direction, e.g., of 3 mm to 20 mm, for example, of 13 mm.
[0016] In one embodiment, the first concentrator and the second concentrator have reflective surfaces (mirror surfaces) and / or transparent bodies as light-deflecting devices. The reflective surface can, for example, be an aluminum layer vapor-deposited on a suitable carrier. Alternatively, the light-deflecting device can also be designed as a transparent body (for example, glass or Plexiglas), which is configured such that a corresponding light deflection is generated in the concentrator by means of total internal reflection at at least one outer edge.
[0017] In one embodiment, at least one concentrator of the first concentrator and the second concentrator is designed as a Compound Elliptical Concentrator (CEC) or as a Compound Parabolic Concentrator (CPC). A CEC is composed of opposing elliptically shaped reflective surfaces, and a CPC is composed of opposing parabolically shaped reflective surfaces. In particular, when using at least one concentrator in the form of a CPC, e.g., when using a first concentrator as a CPC and a second concentrator as a CPC, it is ensured that a particularly high efficiency is achieved with regard to the illumination output. In addition, the efficiency can be further increased if a Lambertian radiator (e.g.,A row of LEDs arranged transversely next to one another without an additional lens is used, and the light source is positioned in the area of the first input opening of the first concentrator. Alternatively, if the light source is positioned at a distance from the input opening, an additional lens can be used to focus the light onto the first input opening.
[0018] In one embodiment, the first concentrator is arranged adjacent to the second concentrator such that a first tangent at a first point of contact on an inner concentrator mirror surface of the first concentrator and a second tangent at a second point of contact on an inner concentrator mirror surface of the second concentrator lie one above the other. With such an arrangement, the concentrator mirror surfaces lie directly against one another and form a continuous transition, so that no additional deflection effects are introduced by the transition from the first concentrator to the second concentrator. This also has a positive effect on efficiency.
[0019] In one embodiment, one or more focal points of the first concentrator are arranged in the region of the input opening of the second concentrator. This measure also allows a high degree of efficiency with regard to the illumination output to be achieved. It is particularly advantageous if the focal points of the reflective parabolic surfaces for the first concentrator are arranged as CPC on the two sides of the cross-section of the first input opening, and the focal points of the reflective parabolic surfaces for the second concentrator are arranged as CPC on the two sides of the cross-section of the second output opening.
[0020] The following parameters for a concentrator unit, in which the first concentrator and the second concentrator are each designed as a CPC, can be derived from the conservation of etendue. Furthermore, for simplicity, it is assumed that the acceptance angle θ is approximately the same for the first concentrator and the second concentrator and that the refractive index n = 1. If the acceptance angle of both concentrators is known, the acceptance angle θ for the calculation can be determined, for example, as the arithmetic mean of the acceptance angle of the first concentrator and the acceptance angle of the second concentrator. Furthermore, the CPC is advantageously designed such that the radius of the first input opening is smaller than the radius of the second output opening. All dimensions given below are meant in the plane of the cross-section.
[0021] In one embodiment, in the case that the first concentrator and the second concentrator are each designed as CPC, the length Lv of the concentrator unit results from the equation
[0022] L v = (α c + b c + α d + b d ) cot(θ) where a c the radius of the outlet opening of the second concentrator, bc the radius of the inlet opening of the second concentrator, a d the radius of the inlet opening of the first concentrator, b d is the radius of the exit aperture of the first concentrator and θ is the acceptance angle.
[0023] In one embodiment, in the case that the first concentrator and the second concentrator are each designed as CPC, the radius a c the outlet opening of the second concentrator from a c = a d + b v sin(0), where ad is the radius of the entrance opening of the first concentrator, b vis the length of the second section of the entrance aperture of the second concentrator and 0 is the acceptance angle.
[0024] The surface brightness measured at the sample location decreases with distance from the second exit aperture. The extent of this divergence can be determined from the illuminator's parameters as follows:
[0025] The exit angle relative to the exit plane is therefore The above object is also achieved by a lighting device for inspecting an object, wherein the lighting device comprises a light source and a concentrator unit as described above. The light source and the concentrator unit are configured in such a way, and the light source is arranged in the input opening of the first concentrator in such a way that the light emitted by the light source enters the first concentrator and is transmitted by the concentrator unit to the object to illuminate a predetermined inspection area of the object. In particular, when the light source is designed as a Lambertian radiator, a high degree of efficiency is achieved by the above lighting device.In one embodiment, the light source is arranged in the first entrance opening such that the radiation angle of the light source is matched to the acceptance angle of the first concentrator and a very large part of the radiation emitted by the light source (e.g. at least 90%, in particular at least 95% of the emitted radiation) is passed on within the first concentrator in the direction of the second concentrator.
[0026] In one embodiment of the illumination device, the light source and the concentrator unit are each configured in a line shape, and the concentrator unit is configured to generate line-shaped illumination of the specified inspection area, wherein the light source comprises, for example, a plurality of LEDs arranged next to one another in a row or other Lambertian / collimated light sources. In a further embodiment, the light source comprises at least two rows of LEDs arranged next to one another. The rows are arranged next to one another in a direction perpendicular to the transverse direction and, for example, parallel to one another. This allows, for example, a wider inspection area to be illuminated.
[0027] The above object is also achieved by an inspection system for inspecting an object, wherein the inspection system has a lighting device as described above and a camera, wherein the lighting device is configured such that it illuminates a predetermined inspection area of the object, wherein the camera is configured such that it records images of the predetermined inspection area of the object along the observation path, wherein the object is arranged behind the second output opening of the concentrator unit in the direction of propagation of the light. The inspection system is arranged with all its elements (lighting device and camera) on the same first side of the object, e.g., above the object. In addition, an additional camera can be used if necessary, which, e.g.,For a transparent object, the illuminated inspection area is observed from the second side, which is opposite the first side. The inspection system has the same advantages as those already described above for the concentrator unit and the illumination device. Reference is therefore made to these. In one embodiment of the inspection system in which the concentrator unit and the light source are linear, the camera is designed as a line-scan camera, for example, a TDI line-scan camera.
[0028] In one embodiment, a slight inclination of the concentrator unit by an angle of inclination <5 in one direction, so that the camera's observation path runs perpendicular to the object's surface, is advantageous. This makes it easier to avoid or correct any optical errors in the camera. The inclination is advantageous because the observation path runs laterally, obliquely to the axes of the two concentrators. In the embodiment, the angle of inclination 5 of the concentrator unit to the perpendicular to the object's surface is determined from the length L. v the concentrator unit, the radius bc of the inlet opening of the second concentrator and the length bv of the second section of the inlet opening of the second concentrator.
[0029] Further advantages, features, and possible applications of the invention are described below using an exemplary embodiment and the figures. All described and / or illustrated features form the subject matter of the present invention, regardless of their summary in the claims and their references.
[0030] They show schematically: Fig. 1 an embodiment of an inspection system according to the invention in a perspective view from the side,
[0031] Fig. 2 shows the embodiment of the inspection system according to Fig. 1 in a cross-section,
[0032] Fig. 3 an embodiment of a concentrator unit with light source and object in a cross section,
[0033] Fig. 4 shows the cross section of the concentrator unit according to Fig. 3 with a plurality of light beams running in the concentrator unit.
[0034] Fig. 1 and 2 schematically show an embodiment of an inspection device which is arranged above an object 5. This is, for example, a circuit board which moves in the direction indicated by arrow 6 beneath the inspection device and is thereby illuminated along a linear inspection area 7 which extends in a transverse direction (see arrow 8) which is perpendicular to the direction of movement (arrow 6).
[0035] The inspection device consists of a line-shaped light source 12, which, for example, has a row of LEDs arranged next to one another in the transverse direction. Furthermore, a concentrator unit 10 is provided, which transmits the light emitted by the light source 12 to the object 5 and illuminates the object in the inspection area 7. The concentrator unit 10 deflects the light provided by the light source 12 such that the light output of the light source 12 is transported to the inspection area 7 with high efficiency. The light path is illustrated in Figs. 1 and 2 by means of the arrow 14. Furthermore, a line-scan camera 16, for example a TDI camera, extending in the transverse direction (arrow 8) is provided. This line-scan camera is arranged on the side of the concentrator unit 10 opposite the object 5 and observes the object 5, in particular the illuminated inspection area 7, and takes images.Based on the images of the inspection area 7 along the moving object 5, for example, an analysis of the quality of the object 5 can be performed. In particular, Fig. 2 shows that the concentrator unit 10 is arranged at an angle relative to the perpendicular to the surface of the object 5. This ensures that the camera 16 is looking perpendicularly at the surface of the object 5.
[0036] The structure of the concentrator unit 10 of the exemplary embodiment is explained in more detail below with reference to Figs. 3 and 4, wherein these figures represent the cross-section parallel to the transport direction (arrow 6) and perpendicular to the transverse direction (arrow 8), respectively. The dimensions are given below with reference to this cross-section. The concentrator unit is composed of a first concentrator 21 in the form of a CPC and a second concentrator 22, which is also designed as a CPC. Both concentrators 21, 22 accordingly have two parabolic reflectors arranged opposite one another, as shown in Figs. 3 and 4. The first concentrator has a first inlet opening 21E with a radius ad and a first outlet opening 21A with a radius b d The second concentrator 22 has a second inlet opening 22E with a first section having a length / diameter 2 xb dand a second section b v . In the following, the length of the second entrance opening 22E is also referred to as b c used, where 2 xb c = 2 x b d + b v . A second exit opening 22A, which also represents the exit opening of the entire concentrator unit 10, has the radius a c . It should be noted that the indication “x” in the above paragraph and in Fig. 3 is intended to symbolize the multiplication by the factor specified before (factor 2).
[0037] The first concentrator 21 is arranged in a scattering configuration, and the second concentrator 22 is arranged in a light-collecting configuration. The acceptance angle, shown in Fig. 3, for the first concentrator 21 is denoted by θ. d and for the second concentrator 22 with θ c designated.
[0038] The second concentrator 22 is arranged directly behind the first concentrator 21 in the direction of light propagation (arrow 14), such that the tangent to the inner reflecting surface at point 27 of the first output opening 21A of the first concentrator 21 and the second input opening 22E of the second concentrator 22 overlap. The first concentrator 21 and the second concentrator 22 therefore merge into one another in such a way that no additional reflections of the light guided in the concentrator unit occur at the transition.
[0039] Furthermore, the first concentrator 21 overlaps along the cross-section in the first section of the second entrance opening 22E of the second concentrator 22. The second section adjacent along the cross-section forms an opening 25 through which the camera 16 observes the illuminated inspection area 7 along the observation path 18. This enables very simple recording of images of the inspection area 7. The observation path 18 is arranged at an angle 5 to the axes of the concentrators 21, 22, shown with dash-dotted lines. The object 5 has a perpendicular with the same inclination, so that the camera 16 looks perpendicularly at the object 8.
[0040] The light emitted by the light source 12 arranged in the first entrance opening 21 E within the acceptance angle (2 x θ d) is reflected on the parabolic inner surfaces of the first concentrator 21 in such a way that it passes through the output opening 21A of the first concentrator 21 into the second input opening 22E of the second concentrator 22, where it is guided further in the direction of the second output opening 22A of the second concentrator 22, where the light exits the concentrator unit 10 and illuminates the object 5 arranged below in the inspection area 7. The second output opening 22A is at a distance d from the surface of the object 5 (unlike what is indicated in Fig. 3, this is measured, for example, in the center of the output opening 22A).
[0041] Using the equations given above, the concentrator unit can be adapted to the requirements of the respective inspection task. The design of the concentrator, shown in cross-section in Figs. 3 and 4, is identical along the entire transverse direction (arrow 8 in Fig. 1).
[0042] For example, the concentrator unit 10 can be dimensioned such that the radius ad of the first inlet opening 21 E of the first concentrator is 2.5 mm. The radius a c of the second output opening 22A of the second concentrator can be, for example, 3 mm. The acceptance angle θ d of the first concentrator 21 can be 15 º, for example, while the acceptance angle θ c of the second concentrator 22 can be selected to be 20º. This results in a length of the concentrator unit L for the combination of two CPCs as described above. v of approximately 110 mm and a width bv of the opening 25 for the observation path (arrow 18) of the camera 16 of 16 mm. The concentrator unit can have a transverse extension (arrow 18) of 200 mm to 500 mm. The distance d of the object 5 from the second exit opening is 3 mm in this example.
[0043] Fig. 4 illustrates the path of some light rays in the reflector unit 10.
[0044] The concentrator unit 10 according to the invention, the illumination device, which is composed of the concentrator unit 10 and the light source 12, as well as the inspection device, which comprises the illumination device and the camera 16, can offer a simple possibility for the inspection of an object, with which the power of the light source 12 can be transported to the object with a very high degree of efficiency.
Claims
AMENDED CLAIMS received by the International Bureau on 26 March 2024 (26.03.2024) 1. A non-imaging concentrator unit (10) comprising a first two-dimensional non-imaging concentrator (21) with a first input opening (21E) and a first output opening (21A), and a second two-dimensional non-imaging concentrator (22) with a second input opening (22E), the cross-section of which has a first section and an adjacent second section, and a second output opening (22A), wherein the first concentrator (21) is arranged one behind the other in a configuration that scatters the incident light, and the second concentrator (22) is arranged one behind the other in a configuration that collects the incident light, along the direction of propagation of the light, wherein the second concentrator (22) is arranged behind the first concentrator (21) such that the first concentrator (21) overlaps with the second input opening (22E) only in the first section,so that the light emerging from the first exit opening (21A) falls into the second entrance opening (22E) only in the region of the first section, wherein an optical observation path, for example for a camera (16), runs through the second section (25) of the second entrance opening (22E) and the second exit opening (22A).
2. Concentrator unit according to claim 1, characterized in that the non-imaging concentrator unit is designed in a line shape such that the first input opening (21 E), the first output opening (21 A), the second input opening (22 E) and the second output opening (22 A) each have a corresponding gap shape extending in a transverse direction.
3. Concentrator unit according to one of the preceding claims, characterized in that the second concentrator (22) is arranged directly behind the first concentrator (21) in the propagation direction of the light in such a way that the first concentrator (21) overlaps with the second input opening (22E) in the first section of the second input opening (22E).
4. Concentrator unit according to one of the preceding claims, characterized in that the first concentrator (21) and the second concentrator (22) are AMENDED SHEET (ARTICLE 19) Devices that deflect light have reflective surfaces and / or transparent bodies.
5. Concentrator unit according to one of the preceding claims, characterized in that at least one concentrator of the first concentrator (21) and the second concentrator (22) is designed as a CPC.
6. Concentrator unit according to one of the preceding claims, characterized in that the first concentrator (21) is arranged adjacent to the second concentrator (22) in such a way that a first tangent in a first abutment point (27) on an inner concentrator mirror surface of the first concentrator and a second tangent in a second abutment point on an inner concentrator mirror surface of the second concentrator lie one above the other.
7. Concentrator unit according to one of the preceding claims, characterized in that one or more focal points of the first concentrator (21) are arranged in the region of the inlet opening of the second concentrator (22).
8. Concentrator unit according to one of the preceding claims, characterized in that in the case that the first concentrator (21) and the second concentrator (22) are each designed as CPC, the length L vthe concentrator unit from the equation L v = (α c + b c + α d - b d ) cot(θ), where a c the radius of the exit opening of the second concentrator, b c the radius of the entrance opening of the second concentrator, a d the radius of the inlet opening of the first concentrator, b d is the radius of the exit aperture of the first concentrator and θ is the acceptance angle.
9. Concentrator unit according to one of the preceding claims, characterized in that in the case that the first concentrator (21) and the second concentrator (22) are each designed as CPC, the radius a c the exit opening of the second concentrator from α c = α d + b v sin(0), where a d the radius of the inlet opening of the first concentrator, b v the length of the AMENDED SHEET (ARTICLE 19) second section of the entrance opening of the second concentrator and θ is the acceptance angle.
10. Lighting device for the inspection of an object, wherein the lighting device comprises a light source (12) and a concentrator unit (10) according to one of the preceding claims, wherein the light source (12) and the concentrator unit (10) are set up in such a way and the light source (12) is arranged in the entrance opening (21 E) of the first concentrator (21) in such a way that the light emitted by the light source enters the first concentrator (21) and is passed on by the concentrator unit (10) to the object (5) for illuminating a predetermined inspection area (7) of the object.
11. Lighting device according to claim 10, characterized in that the light source (12) and the concentrator unit (10) are each designed in a line shape and the concentrator unit (10) is set up such that it generates a line-shaped illumination of the predetermined inspection area (7), wherein the light source (12) has, for example, a plurality of LEDs arranged next to one another in a row.
12. Inspection system for the inspection of an object with a lighting device according to one of the preceding claims and a camera (16), wherein the lighting device is set up such that it illuminates a predetermined inspection area (7) of the object (5), wherein the camera (16) is set up such that it records images of the predetermined inspection area (7) of the object (5) along the observation path, wherein the object (5) is arranged behind the second output opening (22A) of the concentrator unit (10) in the propagation direction of the light.
13. Inspection system according to claim 12, characterized in that the camera (16) is designed as a line camera, for example as a TDI line camera. AMENDED SHEET (ARTICLE 19) 14. Inspection system according to one of claims 12 to 13, characterized in that the angle of inclination δ of the concentrator unit (10) to the perpendicular on the surface of the object (5) is determined from the length L v the concentrator unit (10), the radius b c the inlet opening (22E) of the second concentrator (22) and the length b v of the second section of the inlet opening (22E) of the second concentrator (22) can be determined. AMENDED SHEET (ARTICLE 19)