DE102015006012B4 - Luminaire for optical inspection of surfaces - Google Patents

Abstract

Luminaire (1) for optical control of surfaces (2), which distributed over a disc (3) as a surface, alternately darker (5) and lighter (4, 4.1, 4.2), uniformly bright and colored stripes, characterized in that - The disc (3) consists of a transparent, light-conducting material, in the lamps (6) laterally via an edge (7) couple light, wherein - the darker stripes (5) of the disc (3) both on the side facing the viewer (8) and to the side facing away from the viewer (9) are provided so smoothly and without structure, so that a total internal reflection on both sides of the disc (3) prevents the exit of the laterally coupled light, and wherein - the lighter stripes ( 4, 4.1, 4.2) of the disc (3) consist of alternating areas of total reflection and light outcoupling and are structured on the side facing away from the viewer (9), so that the total internal reflection on the viewer facing Se ite (8) is suppressed at the points with light extraction and at these points laterally coupled light emerges from the surface of the disc (3), and that - the lighter strips (4, 4.1, 4.2) facing away from the one on the viewer of the disc Side (9) present fine pattern (10) with in the range of less than 1 mm, preferably less than 0.2 mm alternating areas of total reflection and light outcoupling, wherein - within the lighter strips (4, 4.1, 4.2), the area ratio of Areas with light extraction to areas with double-sided total reflection inversely proportional to the distance to the edge (7) with light coupling, so that with increasing distance of the areas of the edge (7) increase the area proportions of the areas with light extraction.

Description

The invention relates to a luminaire for optical control of surfaces, which distributed over a disk as a surface, alternately darker and lighter, uniformly bright and colored stripes.

The quality control of surfaces, especially the quality control of curved surfaces of vehicle bodies, is still a process that can only be carried out satisfactorily by man and not by machine. When inspecting individual body parts or the finished vehicle, the effects of the different production processes become apparent. The person skilled in the art is able to recognize whether the body press presses the desired shape, whether the shape of the body tends to form errors due to thermally induced, mechanical stresses and whether voids or defects in the steel sheet of the cold-formed body panels are present. Finally, the person skilled in quality control can test the process of multi-layer coating. The body part is first primed by phosphating. If the layer thickness of the phosphating varies over the large-area surface of the body part, slight form errors in the body curvature can occur. The flow behavior of the still liquid dip coating can lead to differences in layer thickness between when flowing higher and lower components when flowing after immersion in the viscous dip coating. Finally, the uniform nature of the further primer is the cause of a uniform coating order. The varnish itself can have a multiplicity of visually recognizable differences in multilayer varnishes, such as a different reflection behavior with respect to diffuse ambient light and brilliant highlight light. Furthermore, typical polishing traces can lead to hologram-like impurities in the paint, which produce optically undesirable defects. Further, the surface finish of today's waterborne paints that produce a desirable orange peel-like structure upon curing may mask minor manufacturing defects such as splinters remaining on the surface during immersion priming and trapped in the thermosetting paint or unevenly over the large area applied or unevenly cured paint spots. In addition to the possible sources of error described here, the person skilled in coachbuilding knows a large number of further production errors or their artifacts. In the quality control therefore Nuanceure, coachbuilders, metallographers, painters, chemists and process engineers are used, which know possible sources of error of their entrusted production processes in detail and recognize these in the quality control.

For the optical examination of curved body surfaces, it is important to have a light source with constant brightness and light distribution over time for quality control. The skilled person sometimes has very high demands on the type and quality of the light source in order to be able to recognize the production-related deviations of the surface condition from the ideal state, which are in part concealed by the type of coating. Firstly, it is important that the test light is emitted evenly from the light source at a very large angle. The test light should have a reproducible spectrum and thus a predetermined color. In addition, the color rendering index should meet certain quality requirements. The ratio of diffuse light components to brilliance of the light source should also be reproducible and should not change as far as possible over the life cycle of the test light and also between different test lights. The ratio of polarized light to non-polarized light of the test light, expressed as a Stokes vector, should either be very pronounced depending on the type of use or, in the other extreme case, no polarized light should be present at all. Finally, test samples used in the light source for the examination of the surface should be such that the eyes of the quality inspector are not excessively stressed by varying light-dark contrasts, which helps to avoid fatigue-related control errors.

In the German patent DE 198 15 250 A1 a light source for quality control purposes is disclosed. In order to provide the quality inspector with a desirable test pattern for controlling the nature of the surface curvature of body components, high contrast fringe patterns are produced in the large area light source by a change of rod lenses and prisms. This light source described there using fluorescent tubes with a predetermined color temperature has been proven for use in quality control. However, since the demands on the reproducibility of the surface condition in production are always increasing, the requirements for the type and quality of the test lights used for quality control are also increasing. The last-mentioned test light has the problem that the fluorescent tubes used require a predetermined time for warming up. During the warm-up phase, both the color temperature of the light of the fluorescent tube and the brightness change. The use of rod lenses and prisms is then problematic in the optical examination of the surface condition changing the gaze position, if at a strong angle or Change of location of the eye of the quality inspector on the body surface subject to the test pattern of a certain change. Due to the spatial structure of the light boxes used for the quality inspection, a parallax-related, different orientation of the fluorescent tube rod lens arrangement or fluorescent tube prism arrangement can occur with a strong change in the angle of the Prüfblick, which complicate an interpretation of the thus deliberately generated impression of the reflection image.

In the publication DE 10 2007 063 530 A1 For example, a luminaire for optically inspecting surfaces is taught, in which light and dark stripes are distributed over the surface of a photoconductive disk in one embodiment. However, the brightness (specific emittance) in the areas of the bright stripes requires an improvement in uniformity for the requirements of the described quality control.

For those in the publication DE 100 37 642 A1 disclosed flat lighting devices with a photoconductive plate, the more, z. B. strip-like coupling regions for laterally coupled into the plate light, we proposed to provide diffuse structuring on the side facing away from the viewer side of the plate for the coupling-out areas. In order for a uniform light distribution to be achieved overall over the plate, it is proposed to increase the ratio between the light-extracting partial areas and the remaining, dark area proportions corresponding to the distance to the light source. It remains unclear how the structuring within a lichtauskoppelnden part surface, for example. A lighter strip should be specific, so that the requirement of the most homogeneous brightness for the quality control described within this sub-area can be met.

To achieve at least largely continuously changing brightness gradients is from the document DE 10 2008 038 256 A1 the use of checkered light-dark patterns in camera-based optical surface inspection devices.

In the in the publication EP 0 947 827 A1 It is known in the art for a device for visually inspecting surface-treated components which is based on reflection elements to advantageously use different light colors, polarized light and dimming stages for quality control purposes.

The object of the invention is therefore to provide a luminaire for optical inspection of surfaces, which meets the ever-increasing requirements of a quality inspector.

The object of the invention is achieved in that the disc consists of a transparent, light-conducting material in the lamps laterally coupled via an edge light, the darker stripes of the disc both on the side facing the viewer as well as the side facing away from the viewer as smooth and having no structure such that total internal reflection on both sides of the disk prevents leakage of the laterally coupled light, and wherein the lighter stripes of the disk consist of alternating regions of total reflection and light extraction and are patterned on the side away from the viewer, such that the total internal reflection on the side facing the observer is prevented at the points with light decoupling and at these points laterally coupled-in light emerges from the surface of the disc, and that the brighter strips are present on a side facing away from the observer of the disc the areas of total reflection and light decoupling alternating in the range of less than 1 mm, preferably less than 0.2 mm, wherein within the lighter stripes the area ratio of areas with light extraction to areas with double-sided total reflection conversely logarithmically proportional to the distance to the edge with light coupling, so that with increasing distance of the areas from the edge, the area proportions of the areas with light extraction increase. Further advantageous embodiments are specified in the subclaims to claim 1.

According to the invention it is provided that the test light is provided as a flat luminaire, wherein the surface of the surface-control luminaire has a typical fringe pattern. The special feature of the luminaire according to the invention is that the light is coupled laterally into an edge of a pane made of a transparent material, wherein the coupled light by a double-sided total reflection on both surfaces of the disc, namely on the observer facing the front and to the viewer opposite side does not exit. The polished, crystal clear surfaces of the disc appear dark.

In order to capture small amounts of leaking light, in a first embodiment of the light on the side facing away from the viewer side, a black, light-absorbing film is used to avoid unwanted backside reflections. By avoiding backside reflection, high contrast ratio stripe light is generated, which helps the quality inspector to visually inspect surfaces with the high contrast light edges. In order to increase the brightness of the bright stripes, it is provided in a second embodiment of the invention that a white or the light reflecting light highly reflective film on the side facing away from the viewer is arranged to produce a back reflection. This increases the light intensity in the bright areas.

For a particularly high-contrast test lamp is provided, in the places of the disc, which are polished and in which there is a double-sided total reflection, a black, light-absorbing film is present to avoid unwanted back reflections in the dark areas, and in the places Disc, where a total reflection on the side facing the viewer is suppressed and the bright stripes or spots are arranged, a white or a light-reflecting, light-reflecting film on the side facing away from the viewer is arranged to produce a backside reflection.

So that light emerges as a striped pattern from the surface facing the viewer, the rear side remote from the observer is structured at the locations where a light strip is to be generated. The structuring prevents the total reflection by light scattering on the observer facing the front. It is therefore not intended simply roughen the rear surface, whereby light would emerge on the side facing away from the viewer side and would produce disturbing backlight, but the reflection angle is deliberately changed by the structuring that the total reflection is suppressed on the side facing the viewer, so that the laterally coupled-in light preferably emerges from the pane on the side facing the observer. Surprisingly, it has been found that the light of such a surface light compared with known test lights has improved properties. First, the ratio of polarized light to unpolarized light is uniform over a very wide viewing angle. The image of the stripe pattern of the surface light changes only insignificantly, if at all, to the geometric projection, and not at all when there is a very strong change in the observer's position.

Since the coupled-out light is always decoupled from the disk in a proportion determined by the structuring, the disk behaves as an optical fiber with an extinction behavior. The known from spectroscopy extinction of light leads to a logarithmic decrease in light intensity over a uniformly structured section. As a result, with a uniform structuring, the light intensity in spatial proximity to the light coupling would be stronger than the light intensity at a spatial distance to the light coupling. The test light would show a noticeable reverse vignette effect on a large area.

For large-area test lights is therefore provided according to the invention that the lighter strips of a present on the side facing away from the viewer of the disc fine pattern in the range of less than 1 mm and greater than 0.05 mm, preferably less than 0.2 mm and larger 0.1 mm, alternating areas of total reflection and light outcoupling, wherein within the lighter stripes, the area ratio of areas with light outcoupling to areas with double-sided total reflection conversely logarithmically proportional to the distance to the edge with light coupling, so that with increasing distance of the areas of the Edge increase the area proportions of the areas with light extraction. The backside structuring is not a roughening that leads to a light outcoupling with undesirable backside reflection, but the backside structuring behaves similar to a bevy of small mirrors that emerge from a notch in the back and also throw the light back into the material of the pane but under one Angle, which on the side facing the viewer does not fall below the gloss angle, from the total reflection. As a result, the light exits from the material of the disc. The amount of light coupled out per unit area depends on the ratio of the specular surface portions, which are structured similarly as in a Fresnel lens or in a mirror matrix, to area proportions which do not act as light coupling-out. In order to avoid edge effects at the boundaries between light-extracting surfaces and the non-light coupling surfaces, which may nevertheless result in backside reflection of light, or at least to minimize the amount of unwanted backside light, it is advisable to minimize the frequency between both surface types hold to produce fewer interfaces per unit area. However, the frequency must not be too large to avoid the formation of a recognizable to the human eye grid surface, which could lead to an undesirable interference pattern in the quality control.

In order to avoid high-frequency banding, it is therefore provided in an embodiment of the luminaire according to the invention that the areas with total reflection and areas with prevented total reflection are arranged in a route pattern or a hexagonal pattern.

The spatial conditions in a production line are usually narrow. Through a test tunnel drive both small vehicles, such as small sports cars, as well as larger vehicles, such as known as SUV vehicles. In order to avoid strong constructive lighting arrangements, which narrow the space for the quality inspector, is in an embodiment of the lamp according to the invention provided that the Lichteinkopplung is made on the side of the disc by very space-saving LED, which preferably produce a white light. The use of LED as a light source has the further advantage that over conventional light sources energy is saved, which has a noticeable financial effect in the large-scale used lights in quality control. Finally, the effect of using the LED is less heat development relative to light production, so that the inspection tunnel, in which a quality inspector resides for a long time, does not become undesirably hot, thus maintaining the concentration capability of the quality inspector operating in a test tunnel in the desired manner for a longer time can be.

For the inspection of paint surfaces, it is helpful for the quality inspector to perform the test with light of different color temperature. Since the test lights presented here have a uniform light coupling, it can be provided in an embodiment of the invention that the light color of the test light is variable.

Since the light synthesized by a single LED does not have a continuous spectrum with a substantially straight curve of the intensity distribution but is characterized by the intensity maxima of the LED used, it is necessary to comply with a color rendering index when choosing the lamps for the luminaire, so that paint colors under artificial light of the invention Lamp as under sky light appear. The color rendering index is a photometric quantity that can be used to describe the quality of the color rendering of light sources of the same correlated color temperature. The correlated color temperature describes a color locus in the usual relative plot of the tristimulus curves in the CIE standard valency system, named after the International Commission (CIE - International Commission I'éclairage). This plot is also known as the CIE standard color chart. The color location of the correlated color temperature is on a curve in the CIE standard color chart corresponding to the color perception of a Planck blackbody, with each blackbody temperature in the range of about 1,000 K to about 10,000 K being perceived somewhat differently by humans Color corresponds. The color perception of a blackbody at different temperatures in a CIE standard color chart corresponds to Planck's blackbody curve or Planck curve for short. An arbitrary color locus in the CIE standard color chart can be assigned to a color location on the Planck curve via lines on which subjectively similar perceived colors with different brightness are located.

When determining the color rendering index, reference colors are exposed to the light to be measured and the reflectance of the reference colors is determined. From the Remissonswerte the color rendering index can be calculated in a known manner. A value of the color rendering index near 100 indicates a high quality of color reproduction.

Since any light color in the CIE standard color panel can be constructed by a variety of different combinations of different light source light sources, namely by constructing the intensity of the different light colors, it is possible to produce any light color with a small number of narrow band light sources. The exact procedure for the construction of a light color from other colors with the help of the CIE standard color chart is the publications of the CIE removable and subject of modern color theory. However, the same light color can be constructed without a human being being able to differentiate it, even with a larger number of different color admixtures. A general rule is that as the number of light colors that produce a light color increases, so does the color rendering index.

In order to enable color reproduction as true as possible to human vision, it is advantageous in an embodiment of the invention if the color rendering index of the lamps used for the luminaires is at least 80. The person skilled in the art is free to choose the individual LEDs within the visual range of the light spectrum in such a way that the color rendering index of 80 is also reached and possibly even increased.

The preselected color rendering index can be constructed at different correlated color temperatures by choosing the light components. In order to further improve the color reproduction of the surface of vehicle paints, it is provided according to an advantageous embodiment of the invention that the correlated color temperature of the lamp used is at least 2,700 K. For the visual examination, color temperatures have proven to be advantageous in the range of 3,800 to 4,200 K, preferably 4,000 K, perceived as being "warm" and in the range of 6,300 K to 6,700 K, preferably 6,500 K, which is perceived as "cold".

In an embodiment of the invention, it is therefore provided that the lamps of the luminaire are LED lamps which have LEDs with different color spectrum on a substrate, wherein a control device varies the intensity of the different LEDs with different color spectrums on request in such a way that the color location of the accumulated light spectrum of different LEDs with different color spectrums in the tristimulus diagram is always on the Planckian Schwarzstrahlerkurve, wherein the color locus in the stimulus diagram by the control device between the perceived as "warm" range of 3,800 to 4,200 K, preferably at 4,000 K, and im as "cold "Range from 6,300 K to 6,700 K, preferably at 6,500 K, is variable.

In the event of extreme changes in the angle of the quality inspector's gaze, it is sometimes necessary to temporarily reduce or increase the light intensity of the test light on request. In an embodiment of the luminaire according to the invention, it is therefore provided that the luminaire can optionally be darkened or amplified via an operating unit, or even via a remote control in predefined stages or continuously with respect to normal operation.

For very special test requirements, it may be helpful to use polarized light for quality control. The quality inspector can detect reflectance differences of the paint surface either with the use of a polarized filter or with a practiced view without further aids. Since the human being is able to recognize polarized light without the aid of aids because of the orientation of his spine in the fovea of the human eye (this effect is known as the so-called "Haidingers tuft"), but this requires a considerable amount of practice Experienced quality inspectors recognize very subtle differences in the surfaces of areas of larger paint surfaces with the naked eye when using polarized light. In a very particular embodiment of the invention it is therefore provided that the lamp has a polarizing filter, preferably as HN-50 filter whose polarization direction is horizontal in use of the lamp, wherein when using a polarizer, the material of the disc is preferably low-stress quartz glass and the light coupling happens in the vertical direction. Since the light in the total internal reflection already undergoes a polarization, which is dependent on the position of the mirror angle, the use of low-stress quartz glass helps to avoid an additional reverse vignette effect or a rainbow-colored polarization effect, which can arise when strained plastic in conjunction with a polarization by multiple total internal reflection, the polarization of the light emerging from the lamp and this usually varies with a large dispersion.

Maintaining the quality of light is necessary for long-term use in quality control. In order to prevent the aging-related decrease in intensity of modern high-power LED, it will be striven to replace the LED at regular intervals. In an embodiment of the luminaire according to the invention, it is therefore provided that the lamps are arranged in an exchangeable rail, which rests laterally on the disk, wherein the rail is optically covered by a mask. The mask is not only arranged for cosmetic reasons on the lamp, but also to hide the possibly occurring light cone in the immediate area of the light coupling, which could disturb the quality inspector in the assessment of the workpiece.

The proposed lamp is not used in isolation, but usually a light tunnel is constructed from a variety of test lights, in which the test lights are controlled by a central unit. For the simplification of the control, it is therefore provided in an embodiment of the luminaire according to the invention that a bus contact is provided, via which more than one luminaire can be interconnected to form a composite.

The invention will be explained in more detail with reference to the following figures. It shows:

1 a scene of a surface inspection of a manufactured motor vehicle by a quality inspector,

2 an oversized sketch of a surface defect made visible by the luminaire according to the invention,

3 an example of a stripe pattern used for the surface inspection (pattern coarser than real),

4 a sketch of a cross section through the lamp according to the invention,

5 a more detailed sketch of a cross section through the lamp according to the invention,

6 a more detailed sketch of a cross section through a further embodiment of the lamp according to the invention,

7 a lamp with control device, remote control and bus contact in perspective,

8th a Tristimuluskurve CIE with marked Planck curve.

In 1 is a typical scene of a quality control of a newly manufactured vehicle presented by a quality inspector QP. The quality inspector QP stands for the control next to the recognizable vehicle, which is in a tunnel of a variety of lights 1 is turned off, with the individual lights 1 each show a typical quality inspection typical stripe pattern. The Strip pattern of lights 1 reflected in the shiny body of the newly manufactured vehicle and the quality inspector QP takes a variety of different attitudes to the vehicle for testing, peeks over the surface or tries to recognize the virtual mirror images of the lights. For this, the quality inspector QP bends over the body, squats down, aims at places known to him for the body in order to recognize typical or atypical manufacturing defects. The test sometimes requires a very strong concentration of quality inspector QP, in which the quality of the lights contributes a very significant contribution to the quality inspection.

In 2 is an exaggerated surface defect as a defect D in a hood KH of a vehicle represented by a reflection of the lamp 1 is made visible. During quality inspection, the light becomes the light 1 with a sequence of darker stripes 5 and lighter stripes 4 mirrored on the hood KH and the typical farm of the hood distorts the light of the lamp 1 to a very typical distorted image showing harmonious curves according to the desired shape of the hood in a defect-free vehicle. Depending on the type and location of the unwanted defect, here a small dents as defect D, which can be caused by a faulty cold deformation, a material defect of the plate of the hood, by a faulty primer, paint or underfill, is an untypical and easily recognizable distortion of the harmonic Curve shape easily visible. In modern water-based paints, which have an orange-skin-like structure, the caricature is often very complex, like a traffic light stripe, which is seen through a heavily rainy disc. The quality inspectors often have to work for several hours with very high concentration in the search for errors. The requirements on the quality of the condition of the test light therefore have a very strong influence on the test result.

In 3 For example, an example of a typical test pattern is shown, wherein the roughing or light stripe forming rug is highly coarsened due to the printing resolution possible in the context of this disclosure. The rauting or structuring present in hexagonal patterns is less than 0.5 mm per rhombus and is preferably in a range between 0.1 mm and 0.3 mm. The individual strips of a standard more than 1.20 m high and about 50 cm wide test light, which also have 1.50 m × 0.90 m and can be even larger, alternate each other and include lighter and darker areas with different Brightness values and a very narrow and very bright stripes. Here are the dark stripes 5 without pattern or structuring of the disc 3 and the lighter stripes 4 have the structuring on the side facing away from the viewer. For a visual inspection of the surfaces it has proven to be advantageous if the lighter stripes 4 . 4.1 . 4.2 are interrupted by dark stripes 5 , where the brightness of the stripes 4 . 4.1 and 4.2 by the way of structuring the disk 3 decreases on the side facing away from the viewer.

In 4 is corresponding to the stripe pattern in FIG 3 the disc of the light 1 represented with one edge each 7 on both sides of the disc 3 and a page facing the viewer 8th and a side away from the viewer 9 , lamps 6 , here as oversized sized LED-symbols, are at the edges 7 the disc 3 arranged and these radiate their light sideways in the disc 3 one. On the side facing away from the viewer 9 are in the range of lighter stripes 4 structuring 11 inside the disk 3 provided, the total reflection of the laterally coupled light by falling below the gloss angle on the side facing the viewer 8th Stop, so that in these places, the escaping light a lighter strip 4 . 4.1 and 4.2 generated. In the unstructured places 12 where either the gloss angle is not exceeded or where the area ratio of alternating areas with structuring and without structuring predominates in favor of the unstructured surface portions, a darker band appears 5 ,

In 5 is a somewhat more detailed sketch of the remaining components of the lamp according to the invention 1 shown. In the cross-sectional view are the disc 3 as a central component, left and right one rail each 18 with included lamps 6 putting their light in each of the left and right edges 7 inject. In order to mask any light cone at the location of the light coupling is a mask 19 provided so that the surface of the lamp 1 as they are in 3 is displayed with a uniform brightness appears. Below the disc 3 on the side away from the viewer 9 are the in 4 explained structuring 11 and non-structured jobs 12 arranged to produce the desired stripe patterns. To avoid backside reflections, it is envisaged that the light will be in the area of the dark stripes 5 absorbing black foil behind the disc 3 on the side away from the viewer 9 is arranged and in the field of bright stripes 4 . 4.1 and 4.2 a reflective white or reflective film is arranged.

In 6 is a somewhat more detailed sketch of the remaining components of the lamp according to the invention 1 represented, which has a special configuration in the form of a Polfilters. In the cross-sectional view are the disc 3 as a central component, left and right one rail each 18 with included lamps 6 putting their light in each of the left and right edges 7 couple in, shown. In order to mask any light cone at the location of the light coupling is a mask 19 provided so that the surface of the lamp 1 as they are in 3 is displayed with a uniform brightness appears. Below the disc 3 on the side away from the viewer 9 are the in 4 explained structuring 11 and non-structured jobs 12 arranged to produce the desired stripe patterns. In order to avoid backside reflections, it is provided that a light absorbing black film behind the disc 3 on the side away from the viewer 9 is arranged. For very specific applications in quality control is provided, a polarizing filter 17 on the side facing the viewer 8th to arrange.

In both figures, namely 5 and 6 is not the actual stripe pattern with patterning of the textured spots in the lighter stripes 4 . 4.1 and 4.2 because the resolution is not sufficient in light of this disclosure to provide the lighter roughening over the darker area of the darker stripes 5 with appropriate brightness difference by structuring.

The objective light 1 with its other auxiliary aggregates is in 7 shown. The light with darker stripes 5 and lighter stripes 4 comprises in embodiment of the invention, a central control unit 13 , as well as a control unit 16 for the quality inspector, so that the light 1 can be operated for a short time with a different light output, and an industry-typical bus contact 21 to more than one light 1 to switch to a composite.

In 8th is finally a tristimulus curve 14 from the CIE Normvalenzsystem, which is named after the international commission (CIE - Commission internationale de I'éclairage). The color locus of the LEDs in the luminaire according to the invention can, in the design of the luminaire, be varied by varying the relative luminous intensity of the LEDs used along the drawn Planck black radiator curve 15 can be varied so that the quality inspector can check the surfaces to be tested both with light perceived as "cold" (high temperature up to a maximum of 10,000 K) or as "warm" light (lower temperature from 5,000 K to a maximum of 6,500 K). On the black-radiator curve 15 the preferred color temperatures of the test light of the test light according to the invention at 2,700 K, 4,000 K, 6,500 K are shown. At 10,000 K, the test light is already bluish in color and less suitable for longer-term visual inspection, as this light is perceived as unpleasant.

LIST OF REFERENCE NUMBERS

1

lamp

2

surface

3

disc

4

lighter strip

4.1

lighter strip

4.2

lighter strip

5

dark stripes

6

lamp

7

edge

8th

Page, turned to the viewer

9

Page, facing away from the viewer

10

template

11

Area with structuring (with light extraction)

12

Area with total reflection

13

control device

14

Tristimulus chart

15

Black-body curve to Planck

16

operating unit

17

Polfilterfolie

18

rail

19

mask

20

foil

21

bus contact

QP

quality Control

KH

hood

D

malfunction

Claims (9)

Lamp ( 1 ) for optical inspection of surfaces ( 2 ), which via a disc ( 3 ) distributed as an area, alternately darker ( 5 ) and lighter ( 4 . 4.1 . 4.2 ), uniformly bright and colored stripes, characterized in that - the disc ( 3 ) consists of a transparent, light-conducting material into which lamps ( 6 ) laterally over an edge ( 7 ) Couple light, whereby - the darker stripes ( 5 ) of the disc ( 3 ) both on the side facing the viewer ( 8th ) as well as to the side facing away from the viewer ( 9 ) are provided so smoothly and without structure, so that a total internal reflection on both sides of the disc ( 3 ) prevents the exit of the laterally coupled light, and wherein - the lighter stripes ( 4 . 4.1 . 4.2 ) of the disc ( 3 ) consist of alternating areas of total reflection and light extraction and on the side facing away from the viewer ( 9 ), so that the total internal reflection on the side facing the viewer ( 8th ) is suppressed at the points with light extraction and at these points laterally coupled light from the surface of the disc ( 3 ), and that - the lighter stripes ( 4 . 4.1 . 4.2 ) from a side facing away from the viewer of the disc ( 9 ) present fine pattern ( 10 ) with areas of total reflection and light decoupling alternating in the range of less than 1 mm, preferably less than 0.2 mm, wherein - inside the lighter strips ( 4 . 4.1 . 4.2 ) the area ratio of areas with light extraction to areas with double-sided total reflection inversely logarithmically proportional to the distance to the edge ( 7 ) with light coupling, so that with increasing distance of the areas from the edge ( 7 ) increase the area proportions of the areas with light extraction. Luminaire according to claim 1, characterized in that the areas with total reflection ( 12 ) and areas with limited total reflection ( 11 ) are arranged in a diamond pattern or a hexagonal pattern. Luminaire according to one of claims 1 to 2, characterized in that the lamps ( 6 ) Are LED lamps which are based on a substrate with different or the same color spectrum, wherein a control device ( 13 ) the intensity of the different LEDs with different color spectrums on demand varies so that the color location of the accumulated light spectrum of the different LEDs with different color spectrums in the tristimulus diagram ( 14 ) always on the Planckian Schwarzstrahlerkurve ( 15 ), wherein the color locus by the control device between 2,700 K and 10,000 K is variable, the color locus preferably in the range of a color temperature of 3,800 K to 4,200 K and from 6,300 K to 6,700 K is variable. Luminaire according to one of claims 1 to 3, characterized in that the lamp via an operating unit ( 16 ) in predefined stages or continuously over normal operation either darkened or can be amplified. Luminaire according to one of claims 1 to 4, characterized in that the lamp has a polarizing filter ( 17 ), preferably as an HN-50 filter whose polarization direction is horizontal in use, wherein when using a Polfilters the material of the disc ( 3 ) is preferably low-stress quartz glass and the light coupling takes place in the vertical direction. Luminaire according to one of claims 1 to 5, characterized in that that the lamps ( 6 ) in a replaceable rail ( 18 ) are arranged on the disc ( 3 ) is seated laterally, the rail ( 18 ) via a mask ( 19 ) is optically covered. Luminaire according to one of claims 1 to 6, characterized in that at the points of the disc ( 3 ), which are polished and in which double-sided total reflection takes place, a black, light-absorbing sheet is present to avoid unwanted backside reflections at the dark spots, and at the locations of the pane ( 3 ), where a total reflection on the side facing the viewer is suppressed and the bright stripes or spots are arranged, a white or a light-reflecting, light-reflecting film is arranged on the side facing away from the viewer to produce a backside reflection. Luminaire according to one of claims 1 to 7, characterized in that a bus contact ( 21 ) is provided, over which more than one lamp is interconnected to a composite. Luminaire according to one of claims 1 to 8, characterized in that there is a color rendering index of at least 80 by different LED with different light spectra.

Images