EP3016751B1 - Separation of heat and light for a uv radiation source - Google Patents

Description

UV-curing coatings are used in many different areas. Curing is essentially understood to mean the crosslinking of polymer chains. In UV-curing paints, this crosslinking is induced by UV radiation.

Typically, however, these paints, when applied to a workpiece, contain solvents that must be expelled before curing. This expulsion can be accelerated by increasing the temperature beyond the ambient temperature. The higher the temperature, the faster the expulsion of the solvents. However, a certain paint-dependent temperature (glass transition temperature, chemical decomposition temperature) must not be exceeded. Likewise, the deformation temperature of the material of the workpiece must not be exceeded.

High intensity UV radiation sources are based on gas discharge lamps that emit strong visible light (VIS) and infrared radiation (IR) in addition to the desired UV radiation. VIS and IR contribute to a significant additional increase in temperature when curing paints. However, it must be avoided that the temperature rises during the curing process on the glass transition temperature of the paint. It is desirable to suppress this VIS and IR contribution as possible, while losing as little UV radiation as possible.

Typical UV radiation sources consist of a gas discharge lamp and a reflector element which collects the UV radiation emitted in the direction away from the workpiece and reflects it in the direction of the area of application. The propagating to the application UV radiation is thus composed of direct radiation and reflected radiation together. In the case of a substantially linear source, the lamp is substantially tubular. she can but also exist as a series of individual, substantially point-shaped lamps which are arranged in a row.

In order to attenuate now the unwanted VIS and IR content of the emitted radiation of the lamp, which falls within the scope, the reflector element can be provided with a coating which reflects the VIS and IR radiation as little as possible. This can be done through an absorbing layer, but is preferably carried out as a dichroic thin film coating which on the one hand highly reflects the UV component and transmits VIS and IR, i. deflects away from the field of application. Such a UV source reduces the VIS and IR radiation in the field of application by a factor in the range of 2-5, depending on the reflective element (typically cylindrical elliptic element).

In this way, however, there is no weakening of the VIS and / or IR share for direct radiation. In addition, even a substantial residual portion of the VIS and IR radiation, which is not transmitted by the coating of the reflector, comes into the field of application.

Further suppression of the VIS & IR radiation can be achieved by an additional deflection mirror positioned in the beam path of the direct radiation. This deflection mirror should reflect the UV radiation as well as possible, but should reflect the VIS & IR radiation as poorly as possible. This deflection mirror is designed as a flat mirror. Usually, a glass plate with dichroic thin film filter coating, which is arranged at an angle of 45 ° to the main beam of the UV source, is used. The application area is then located downstream in the beam path of the UV radiation reflected by the deflection mirror.

The UV radiation is deflected by this deflection mirror in the 90 °, while the VIS & IR radiation is transmitted and thus not directed to the application area.

Depending on the reflector element and the deflection mirror, suppression of the VIS & IR radiation is achieved by factors of 10 to more than 20. Without Deflection mirror, as described above, only achieved attenuation factors of 2-5. While typically more than 80% of the UV radiation can be collected with the reflector element of the lamp, with the additional deflection mirror, depending on the design and geometric arrangement, typically 30-50% of the UV radiation is lost up to the area of application. This results in a ratio of the light output of UV / (VIS & IR) in the range of more than 10: 1 of the relative proportions with a typical mercury medium-pressure gas discharge lamp. By contrast, without a deflecting mirror, this ratio is typically only 2: 1 to 4: 1. This lower UV radiation with the deflecting mirror could, if available, be compensated by a stronger UV lamp without unduly increasing the VIS & IR radiation fraction. However, the necessary cooling of the lamp with intensive UV sources sets technical and economic limits to the power increase; In the case of application, these can lead to greater distances to the UV source, which in turn reduces the desired UV radiation intensity in the field of application.

However, the use of the dichroic deflection mirror leads to an extension of the light path between the UV source and the application, typically by about 70% of the length of the deflection mirror.

The corresponding situation is in the FIG. 1 with respect to the reflector radiation and in FIG. 2 with respect to direct radiation. In the figures, the UV radiation is shown as a dotted line, while the radiation of the VIS & IR is shown as a dashed line. The total radiation is shown as a solid line.

It will be in FIG. 2 clearly that a large part of the reflected UV radiation does not propagate to the application area hatched in the figures.

The extension of the beam path therefore has the consequence, above all for direct radiation, that the intensity of the UV radiation per unit area (area intensity) is reduced, in particular also in the field of application, due to the opening angle into which the radiation is emitted. To cure a lacquer layer, a certain dose is required, which is due to the product of radiation intensity and exposure time (more precisely, by the temporal integral of the intensity). The lower areal intensity described above can only be made up by increasing the exposure time to achieve the required dose. This leads to a longer process time and thus to higher process costs.

However, the lower surface intensity described above can still have an additional, serious disadvantage: common UV-curing coatings show a non-linear curing behavior in relation to the surface intensity. This means that the degree of cure is not only proportional to the exposure dose, but decreases disproportionately with smaller surface intensity above a certain threshold. If the area intensity is too small, no complete curing can take place.
The lesser areal intensity can be partially compensated for by choosing a configuration of the reflector element such that the light is directed into the area of application in approximately collimated or even partially focused form. In the case of non-flat components with inclined side surfaces or indentations the disadvantage that these areas are exposed to substantially less UV light. By prolonged exposure, the required exposure dose can at best be achieved if the resulting overexposure of the flat areas does not entail any disadvantages, and the minimum necessary intensity can still be achieved. If this is not so, there is still the possibility of rotation of the components during the relative movement of the components to the UV source, but this additional movement means a significant overhead in the mounting of the components and the means for movement, and the disadvantages in a lower arrangement density of the components in the curing plant and a substantial extension of the exposure times.

These disadvantages associated with the use of the deflection mirror could in turn be circumvented by higher power UV sources. In addition to the higher cost of a stronger UV source, however, the additional waste heat to be dissipated also adds weight. In applications with high UV radiation performance, such as those used in production applications, increased system temperatures lead to process drifts as well accelerated aging defects in equipment and facilities. Although these can usually be reduced or eliminated with additional cooling devices, which in turn is associated with additional investment and operating costs.

The inventor has found that the above-described disadvantages can be greatly reduced by a deflection mirror having a substantially concave surface shape. Not only can the curved path compensate the extended beam path readily, but also a partial focusing of the reflected UV radiation, at least in one plane, can be achieved, which leads to an increase of the surface intensity. The shape of the curved deflection mirror is dependent on the exact position and orientation of the application.

The substrate of the curved deflection mirror is preferably permeable to VIS & IR radiation. As substrate material therefore, for example, glass and plastic come into question, it should be noted that the substrate is exposed to high temperatures and a UV residual. However, it would also be possible to choose a material for the substrate which absorbs VIS & IR efficiently, but this would be strongly heated by the absorbed power and therefore would have to be cooled separately.

In order to achieve the optically required properties, a concavely curved glass surface can be coated with an interference filter. The interference filter is constructed, for example, as a thin-film alternating layer system, wherein the near-surface layers provide for the reflection of the UV radiation and the alternating layer system as a whole forms an antireflection layer for the VIS & IR radiation. However, the problems associated with producing the curved glass surface can only be overcome with great effort. Another challenge is the angular dependence of the optical behavior of the interference filters. On the one hand, when coating curved surfaces, the difficulty arises in achieving a uniform coating over the entire optically relevant surface. On the other hand, for optimal functioning, this embodiment requires so-called gradient filters in order to position-dependent angles of incidence. However, the available coating technology is able to at least partially overcome this problem, even if this involves a great deal of effort and thus, in turn, costs.

The problem with the curved mirror solution is that, in some applications, sometimes the distance from the radiation source to the area of application of the radiation changes. This is the case, for example, when large substrates provided with a lacquer layer have to be exposed to UV radiation which lie in one plane and UV radiation is to be applied to UV radiation with the same curing apparatus but also small substrates positioned on a spindle the spindle, the substrates and thus the application area are closer to the deflection mirror. In the worst case, it is then necessary to exchange the curved deflection mirror by a deflection mirror with a different curvature.
For example, describes US 4644899 A the use of a double mirror configuration and DE 10352184 A1 a configuration with curved reflecting surfaces.
There is therefore a need for an easy-to-implement but efficient irradiation device for UV radiation, with which it is achieved that an application area is exposed to UV radiation in sufficient surface intensity.

According to the invention the object is achieved according to a preferred embodiment in that a deflecting mirror composed of planar mirror strips is used, wherein the plane mirror strips are inclined relative to one another such that they at least roughly recreate a desired curvature. At least two strips are used, but preferably more than two, and more preferably three strips are used.

Thus, the two main disadvantages of the curved shape can be easily avoided. The coating of the mirror strips can be done so that initially flat glass is coated. Such a coated glass plate is then cut into strips and these strips are fastened in a holder element. This holder element is designed such that each of the mirror strips with an orientation at a predetermined angle to the main beam of the UV Source comes to rest. The individual angles are chosen so that as much UV radiation falls within the scope of application. Due to the fact that the mirror strips essentially transmit the VIS & IR radiation, this proportion in the field of application remains small in any case.

With appropriate individual choice of the spectral properties of the thin film mirror layer for each mirror strip both requirements can be further optimized. It can therefore be coated for each angle a separate glass plate with specifically optimized for this angle thin film interference filter. The deflecting mirror according to the invention is then assembled from strips of differently coated glass plates.

According to a particularly preferred embodiment of the present invention, the fastenings with which the mirror strips are fixed to the holder are designed so that they can rotate at least over a certain angular range about an axis parallel to the longer edge of the mirror strips. This makes it possible to adjust the modeled curvature of the deflection mirror and thus to optimize the UV radiation power for different application levels.
With adjustable angles of the mirror segments, the illumination of the various surface elements of 3-dimensional components with indentations and side surfaces can be made much more uniform and thus improved by adjusting the segments so that the light in a focused form with beam proportions over a wide angular range in the Scope of application. Although this results in a slightly lower intensity for the flat areas, a more homogeneous exposure over the entire surface of the component is achieved. This embodiment allows a simple and above all flexible adaptation of the angular distribution and the spatial distribution of the irradiation light. The adjustment of the angle of these mirror segments can also be done via externally controllable drives, which opens up the possibility, process-controlled controlling the exposure of different shaped elements to optimize run. In a further refinement, the mirrors can also be moved through the field of application by means of drives designed in this way, synchronously with a movement of the workpieces. In this way, the illumination of the surface shape of the workpieces can be dynamically adjusted and optimized.

• Figur 1 zeigt eine UV Bestrahlungsanordnung mit planarem Umlenkspiegel sowie den Strahlengang der Reflektorstrahlung.
• Figur 2 zeigt die Bestrahlungsanordnung gemäss Figur 1 sowie den Strahlengang für die Direktstrahlung
• Figur 3 zeigt eine Bestrahlungsanordnung gemäss einer bevorzugten Ausführungsform der vorliegenden Erfindung wobei der Umlenkspiegel aus drei Spiegelstreifen gebildet wird.
• Figur 4 zeigt eine mögliche Halterung für einen erfindungsgemässen Umlenkspiegel.
• In Figur 5 ist eine dementsprechende Draufsicht der in Figur 4 dargestellten Halterung gezeigt.
• Figur 6a zeigt eine Aushärteeinheit
• Figur 6b zeigt ebenfalls eine Aushärteeinheit
• Figur 7 zeigt ein zu bearbeitendes Bauteil dessen Querschnitt ein Kreissegment darstellt.
• Figur 8 zeigt das positionsabhängige Profil der Dosis
• Figur 9 zeigt die Variation der Leistung der UV Quelle synchron mit der Bewegung des Bauteils.
• Fig 10 ist das Ergebnis für die örtliche Verteilung der UV Strahlungsdosis auf der Oberfläche der angenommenen Bauteile gezeigt, je für die Konfiguration von Fig 6a und Fig 6b

The invention will now be explained in detail by way of example with the aid of the figures.

• FIG. 1 shows a UV irradiation arrangement with planar deflection mirror and the beam path of the reflector radiation.
• FIG. 2 shows the irradiation arrangement according to FIG. 1 and the beam path for direct radiation
• FIG. 3 shows an irradiation arrangement according to a preferred embodiment of the present invention wherein the deflection mirror is formed from three mirror strips.
• FIG. 4 shows a possible holder for a deflection mirror according to the invention.
• In FIG. 5 is a corresponding top view of in FIG. 4 shown holder shown.
• FIG. 6a shows a curing unit
• FIG. 6b also shows a curing unit
• FIG. 7 shows a component to be machined whose cross section represents a circle segment.
• FIG. 8 shows the position-dependent profile of the dose
• FIG. 9 shows the variation of the power of the UV source in synchronism with the movement of the component.
• FIG. 10 is shown the result for the local distribution of the UV radiation dose on the surface of the assumed components, depending for the configuration of Fig. 6a and Fig. 6b

In reality, the substrates are often moved through the application area. For example, on a circular motion when it is mounted on a so-called spindle. As a result, a repetitive exposure of the paint is achieved. With this movement, the undesirable temperature increase is further reduced because the surface may cool during the angular range of rotation away from the field of application.

In the following, a quantitative comparison of the cumulative UV dose (intensity x time) to a flat substrate moved through the application area is made, the reference being made without the dichroic mirror for which the dose = 100 is assumed. The dichroic mirror in the case assumed here has a reflection efficiency of about 93% for the UV radiation and a transmission efficiency of about 92% for the VIS & IR radiation. For the UV dose in the range of application, a value of about 65 is determined, for the VIS + IR dose, however, a value of about 25, i. the flat dichroic mirror reduces the unwanted radiation by 75%, while reducing the desired UV radiation by only 30%.

Going from the flat deflecting mirror to two mutually inclined mirror strips, the result is a substantially higher UV dose of 79, (compared to 65 for the flat deflecting mirror). In contrast, the VIS & IR dose increases slightly to 28 (compared to 25 for the flat deflection mirror).

With a further division of the deflection mirror in 3 stripes, as in FIG. 3 shown, the UV dose in the scope can be further improved. For this in FIG. 2 In the case shown schematically, a UV dose of 83 is obtained, ie a 30% increase over the flat deflecting mirror, while the VIS and IR dose increases only to about 29.

As the number of mirror segments increases, the efficiency for UV light steering in the field of application can theoretically be further improved. However, then also increases the number of strip edges at which it comes to losses. In addition, the effort in the production of this multi-segment mirror increases.

In addition to the dose of UV radiation essential for UV curing, for certain curing processes an intensity threshold of UV radiation must be exceeded for a certain period of time. While in the case of the flat deflecting mirror for the example given an intensity maximum of approximately 45 units is achieved, a value of approximately 60 is achieved for the deflecting mirror, which consists of two mirror strips, and in the FIG. 3 In the case shown with three stiffeners, even a value of about 80 is achieved. Thus, by dividing the dichroic mirror into stripes, almost the same areal intensity as in the case of a structure without this mirror can be achieved.

Thus, with a non-linear cure-dose relationship, reaching the threshold for that areal intensity can still be guaranteed.

With the present invention, a substantial increase in the desired UV radiation intensity is achieved in the field of application without a significant increase in the unwanted VIS and IR radiation intensity must be taken into account. This has the effect that a curing step of UV-sensitive paint can be done correspondingly shorter and thus can be cured with a higher cycle rate more components per unit time. Alternatively, an equivalent result can be achieved with a weaker UV light source, with the benefits of a lower purchase price of a weaker UV light source and lower operating costs. Further, a higher efficiency of the UV light guide in the field of application has the advantage that necessary cooling of the system and in particular the application area in which the substrates provided with temperature-sensitive paint are on the one hand smaller dimensions and less expensive to build, and on the other hand in the Application can be operated with less energy consumption. In In production-technical plants, the entire waste heat of the curing process must be dissipated with strong air cooling in order to keep the temperature increase in the application area low. With these air streams, intensive filtering must prevent dust particles from entering the stream and thus the paint surfaces that are initially in a viscous state and sticking there. Any reduction of the necessary air flow by reducing the unwanted radiation or improving the efficiency in the UV light guide, as shown in the invention, leads to a possible reduction of these necessary air flows.

The example of a deflecting mirror which is composed of three mirror strips, is in FIG. 4 a holder for the mirror strips shown. In the figure, the mirror strips are indicated in cross section only with dashed lines. The holder comprises fixing elements 3, 7, 9 and 11, which are arranged on the strip at the shorter edge, for example clamped. The fixing element 3 of a strip is connected to the fixing element 7 of an adjacent strip via webs 13, 17 connected by means of a joint 15. The fixing element 9 of the central strip is in this case connected to the fixing element 11 of the other adjacent strip via webs 19, 23 connected by means of a joint 21. The outer strips of the deflecting mirror have additional fixing elements 25 and 29. These fixing elements are fixed to circular arcs 27, 31. They can be moved to adjustment along these circular arcs and then fixed. Circular arc 27 belongs to a theoretical circle whose center lies in the joint 15. Circular arc 31 belongs to a theoretical circle whose center lies in the joint 21.

Preferably, such a holder is provided on both sides of the mirror strip thus arranged. In FIG. 5 a corresponding plan view is shown. With this bracket, the inclination of the mirror strips can be easily adjusted and adjusted.

Another aspect of the present invention relates to facilities and process for controllable illumination of workpieces with UV light for curing UV-sensitive surface finishes In particular, this aspect relates to UV exposure devices for curing UV-sensitive coating layers on surfaces, with a focus on homogeneous or a particular profile following illumination of the paint surfaces on a 3-dimensional workpiece

Surface finishes are used for various surface coating functions, such as mechanical and chemical protective coatings, but also for functions such as special decorative properties such as color or light reflection or light scattering. The paints used are applied by spraying, dipping or painting as a film on the components to be coated and then brought with a curing process in the final state with the desired properties. During the curing step, energy is added to the paint film to accelerate the curing process. In conventional paints, thermal energy is supplied in the form of infrared radiation or by means of a heated gas (air). With suitable ovens or infrared radiators, the lacquer layer can be cured relatively uniformly even on more complex surface geometries. A disadvantage of these methods, however, is the relatively long duration (typically between 10... 100 min) of this curing process, which can make logistics complex and susceptible to disruptions to the process, especially in a series production process. With an alternative class of paints that are cured with the addition of UV light, these problems can be largely eliminated. The curing takes place by irradiation of the paint films with high-intensity UV light sources. Thus, the curing step can be significantly shortened in time, typical are exposure times of 1 ... 10min. Uniform illumination of the coating film with UV light, however, becomes a challenge especially for more complex surfaces and shapes. For 2-dimensional surfaces, a rod-shaped, linear UV source achieves uniform illumination in one dimension; A uniformity in the other dimension can be achieved by a relative movement of the component to the UV source. For more complex surface geometries, the component must also be rotated and / or tilted relative to the UV source, which is a particular challenge for the mechanics of mounting the component in the curing system, which naturally leads to limitations in the Uniformity and uniformity of the properties and quality characteristics of the cured films, or limits the processable surface shapes.

Essential film properties of the cured paint film require a minimum dose of UV light, the changes with over-exposure may be low for these properties. Thus, a lack of UV light at certain points on the surface of the component can be compensated by a longer exposure time, whereby other areas are overexposed. For properties that are more critically dose dependent, the result is a loss of homogeneity

A more homogeneous illumination can be achieved by repeatedly rotating holders for the components. Such fixtures and equipment are costly to purchase, demanding to handle and usually inflexible to use. In addition, the utilization of the maximum through the plant loading area with components is lower.

• Ueberbelichtung:
• Eigenschaften inhomogen, z.B. Versprödung im überbelichteten Bereich, im Bereich unvollständiger Aushärtung mechanisch weniger beanspruchbare Filmeigenschaften.
• Mehrfach rotierende Halterungen für Bauteile bedeuten wesentlichen Mehraufwand in der Herstellung, Bereitstellung, Handhabung und Lagerhaltung von Bauteile-spezifische Halterungen.

Problems of the current state of the art can therefore be:

• Over exposure:
• Properties inhomogeneous, eg embrittlement in the overexposed area, in the area of incomplete curing mechanically less demanding film properties.
• Multiple rotating mounts for components add significant overhead to the manufacturing, deployment, handling, and warehousing of component-specific mounts.

First of all, it has to be clarified how the components impacted by the paint film are moved through an area of application in which UV light is directed by a UV source. The uniform illumination in the dimension perpendicular to the direction of movement is achieved by an elongated form of the illumination geometry in this dimension (rod-shaped UV lamp). For the waveform of the movement of the components, a linear or circular movement is assumed on a cylinder at this point, without restricting the subsequent method erfindungsmässe it. FIG. 6a shows schematically the arrangement in one Curing unit with UV light source. The UV light of the UV lamp is collected via a reflector and guided into an application area in which the paint film is exposed on components and thus cured. The components in the area of application heat up so that the entire light radiation of the UV source in this area of the room is largely absorbed. The paint films are temperature sensitive and the temperature must not exceed a maximum value. This problem is mitigated by cyclically moving the components through the application area, thus allowing the components to cool off during the time they are not within the range of application. For components of limited size, this cyclic movement is preferably on a circular path by mounting the components on a drum and moving this drum about its axis.

An extended embodiment of a curing unit is shown in FIG Fig. 6b shown. With the aid of a dichroic mirror permeable to the UV light and the IR radiation of the UV lamp, the unwanted VIS and IR radiation is led away from the area of application, whereby the temperature rise during the curing process can be further limited.

In the following, the inventive method of a homogeneous exposure of a component having a more complex surface geometry, which is provided with a UV-sensitive lacquer layer, is shown. As an example, a cylindrical component whose cross-section represents a circular segment ( Fig. 7 ).

If this component is guided through the application area on a drum in a circular motion, the exposure (with the intensity x time) of exposure to UV light results in a position-dependent profile as in FIG Fig. 8 shown, each for a curing unit as in Fig. 6a and 6b ,

The dose drops on the circular cylinder segment from the center to the edge of the component by about 30%. According to the invention, the power of the UV source is changed synchronously with the movement of the component. The power is set according to a certain temporal curve. To the principle too For the sake of simplicity, a sinusoidal waveform is chosen, whereby the phase is kept in a constant relationship to the rotational movement of the drum ( FIG. 9 ).

The frequency of this modulation of the UV light output is given by the arrangement of the components on the drum, it being assumed that the distance between the components on the circumference of the drum is kept small in the sense of a dense loading. The modulation thus continues to run continuously with each of the components that run sequentially through the application area.

In FIG. 10 is shown the result for the local distribution of the UV radiation dose on the surface of the assumed components, depending for the configuration of Fig. 6a and Fig. 6b , As can be seen from this diagram, the course of the dose from the center to the edge has now almost been eliminated. This result is achieved in this case with a modulation amplitude of the UV light output of about 35% relative to the constant value. The phase of the modulation waveform is chosen so that the modulation power is minimal at the time when the component is at a minimum distance from the UV light source, ie the normal parallel to the axis of the UV light distribution.

The principle of this synchronous modulation of the light output with the movement of the component can according to the invention still be applied to substantially more complex shapes, such as those exemplified here. Essentially any periodic waveform can be used which is in a defined phase relationship to the substrate movement. Both amplitude and phase may themselves be modulated, assuming a frequency that matches or is a multiple of that frequency of the component movement over the range of application. The waveform in this case contains higher harmonic components, each with a specific, fixed phase, so that the synchronization with the component movement is maintained.

The principle of synchronous UV light power modulation for influencing the UV dose on paint films on component surfaces disposed on a rotating drum can also be used to provide an inhomogeneous distribution equalize the dose over the circumference of the drum. Such inhomogeneity may arise due to mechanical inaccuracies, alignment and alignment errors, ect. Furthermore, a deviation from a concentricity (d..h non-constant rotational angular velocity) can lead to inhomogeneous dose distribution over the circumference.

By modulating the UV light output in synchronism with the drum's rotational motion, the UV dose on the components outside the drum can be selectively controlled to provide a more uniform dose distribution across the width of the components. In the case of non-concentricity, the phase of the modulation must be determined from the actual values of a rotation angle sensor which is rigidly connected to the axis of the drum.

Controlling the UV dose across the width of the device using synchronous modulation of the UV light output is not limited to eliminating non-uniformity of the UV dose, but can also be used to force a desired dose distribution across the device to enhance or attenuate a desired property of the cured lacquer film which can be influenced by the UV dose or UV intensity on the surface of the component. In the simplest case, this can be adjusted via the modulation amplitude and the modulation phase, assuming that the fundamental frequency of the modulation is determined by the occupation of the drum with components and the rotational speed of the drum. Both the modulation amplitude and the modulation phase can themselves be synchronously modulated again, the fundamental frequency again having to correspond to the frequency of movement of the components through the field of application.

With this principle, it is even possible to provide different components on the drum with an optimized for the respective components UV dose distribution by different modulation curves are traversed for different rotational angles of the drum. Thus, a much higher flexibility in the application can be achieved.

Another advantage of this synchronous modulation can be that much less different, adapted to the individual components mounts may be necessary in a manufacturing environment in which a variety of components must be exposed. By adapting the modulation curve shapes in the recipe process, dose profiles on different components fixed with the same holders can be compensated.

For more complex surface shapes of the components, it may be necessary to rotate the holders with the components on the drum itself about its axis in order to obtain a sufficiently high exposure dose even on the side surfaces. With the use of the synchronous modulation of the UV light output can the cases of not very steeply rising and falling side surfaces, an increase in the dose on these side surfaces are achieved with non-rotating brackets, which on the one hand is a significant simplification of the necessary equipment equipment (no rotation mechanism), on the other hand, it eliminates the unavoidable loss of throughput that results from rotating holders. In the case of rotating holders usually much more parts can be taken, but the exposure time is extended to the same extent. However, some of the usable surface area in the application space is lost by these additional mechanical means for holder rotation, resulting in the above-mentioned loss of effective throughput.

1. 1. Resultierte Verbesserung im Vergleich mit dem Stand der Technik bzw. konkrete Vorteile, die durch die Anwendung der Erfindung resultierten.
   • Verbesserte Gleichförmigkeit der Eigenschaften und damit der Qualität eines Lackfilms auf einem Bauteil
   • Wesentliche Erhöhung der Flexibilität gegen über neuen oder vielseitigen Bauteile Geometrien, damit verbunden schnellere Umstellungen in der Produktion zwischen verschiedenen Bauteilen
   • Reduzierung der für unterschiedliche Bauteile notwendigen Halterungen, bei ähnlichen Bauteilen kann Ausleuchtung durch Anpassung der Modulation mit gleichen Halterungen gemacht werden.
   • Kann für gewisse einfacheren Bauteile (nicht zu steile Seitenflächen) die Benutzung von drehenden Halterungen nicht notwendig machen, was einerseits die Halterungen damit einfacher und kostengünstiger macht, andererseits den Durchsatzverlust mit drehenden Halterungen eliminiert.

In the previous description, it has always been assumed that a drum on which the components are fastened by means of a holder, and for this drum, a rotational movement about its axis was assumed. All the above embodiments can also be applied in the case of a one-time or cyclic movement of the components mounted on holders by the scope of UV exposure, and thus cover the case of a continuous system.

1. 1. Resulted improvement compared with the prior art or concrete advantages that resulted from the application of the invention.
   • Improved uniformity of properties and thus the quality of a paint film on a component
   • Significant increase in flexibility over new or versatile component geometries, associated with faster conversions in production between different components
   • Reduction of the necessary for different components mounts, with similar components illumination can be made by adjusting the modulation with the same brackets.
   • Can not make it necessary to use rotating brackets for certain simpler components (not too steep side surfaces), making the brackets simpler and less expensive on the one hand, and eliminating throughput loss with rotating brackets on the other hand.

Claims (6)

1. Device for applying UV radiation to substrates in an area of application, wherein the device comprises:

   - a radiation source which emits UV radiation as well as visible light and infrared radiation into a solid angle,

   - a radiation-selective deflecting mirror which reflects most of the UV radiation and transmits most of the VIS & IR radiation,

   characterized in that
   the deflecting mirror comprises at least two flat mirror strips which are inclined relative to one another in such a way that they reflect the diverging direct radiation coming from the radiation source in the direction of the area of application and in doing so at least reduce the divergence and thus lead to an increase in the area intensity in the area of application.
2. Device according to claim 1, characterized in that the deflecting mirror comprises three flat mirror strips.
3. Device according to one of the preceding claims, characterized in that the device comprises means for adjusting the orientation of the mirror strips.
4. Method for manufacturing a device according to claim 1, comprising the following steps:

   - providing a radiation source that can radiate UV radiation as well as visible light and infrared radiation into a solid angle,

   - providing a deflecting mirror which is capable of reflecting most of the UV radiation and of transmitting most of the VIS & IR radiation, characterized in that

   - at least one flat glass plate is coated with an interference filter based on thin film layer systems to provide the deflecting mirror, wherein the interference filter substantially reflects UV radiation at a predetermined angle of incidence and substantially transmits VIS & IR radiation, and after the coating the at least one glass plate is divided into strips and at least two strips are mounted on a support in such a way that they are inclined to each other and reflect the diverging direct radiation coming from the radiation source in the direction of the area of application and in doing so at least reduce the divergence and thus lead to an increase in the area intensity in the area of application.
5. Method according to claim 4, characterized in that strips of glass plates coated with different interference filters are used for assembling the deflecting mirror.
6. Method according to one of the preceding claims, characterized in that the deflecting mirror comprises three strips, preferably exactly three strips.

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