High quality and highly uniform illumination is a critical component for advanced lithography systems and wafer
inspection tools. Homogenizer elements fabricated in calcium fluoride have demonstrated good performance for
deep UV applications. Grayscale photolithography allows for the fabrication of single-sided micro lens array
(MLA) elements with excellent optical performance.
The MLA offers some significant advantages over crossed cylinders fabricated using grayscale photolithography
processes, including the reduction in the number of fabrication steps and the added flexibility of manufacturing noncylindrical
surface geometries. This research presentation reviews the fabrication process and compares grayscale
crossed cylindrical arrays and MLAs in terms of their capabilities and performance.
A new self calibrating optical 3D measurement system using fringe projection technique named “kolibri 1500” is
presented. It can be utilised to acquire the all around shape of large objects. The basic measuring principle is the
phasogrammetric approach introduced by the authors /1, 2/.
The “kolibri 1500” consists of a stationary system with a translation unit for handling of objects. Automatic whole
body measurement is achieved by using sensor head rotation and changeable object position, which can be done
completely computer controlled. Multi-view measurement is realised by using the concept of virtual reference points.
In this way no matching procedures or markers are necessary for the registration of the different images. This makes
the system very flexible to realise different measurement tasks. Furthermore, due to self calibrating principle
mechanical alterations are compensated.
Typical parameters of the system are: the measurement volume extends from 400 mm up to 1500 mm max. length,
the measurement time is between 2 min for 12 images up to 20 min for 36 images and the measurement accuracy is
below 50μm.The flexibility makes the measurement system useful for a wide range of applications such as quality
control, rapid prototyping, design and CAD/CAM which will be shown in the paper.
The projection of fringes onto objects in some 3D-measurement systems has two main reasons: First, to solve the problem of homologous points for the camera images and second, to create a continuous metric in the object space. The second effect leads to the well-known sub-pixeling accuracy. The accuracy of such measurement systems is not limited by the pixel size of the camera. But, depending on some surface-discontinuities (i.e. steps) and the viewing direction of the camera, this principle is not valid for a certain number of pixels. When a camera is viewing "downstairs," these pixels get the phase information from the upper and the lower step. By using our very precise measurement system kolibri, this effect is evident on most complex technical surfaces and is clearly distinguished from statistical noise. We discuss the different circumstances of this effect and give a well-adapted algorithm for eliminating these errors.
For measuring the 3D shape of complex objects by optical methods the optical sensor or the object have to be moved into multiple, overlapping measuring positions so as to view the entire surface. The resulting point clouds taken from the different views then have to be merged into a common coordinate system to obtain the final complete 3D view. Here we propose concepts of 3D-measurement arrangements using structured-light illumination with a digital-light projection unit to obtain a full-body view within a self- calibrating measurement strategy, whereas the necessary merging of the single views takes place fully automatically and done without any marker on the object surface, objects features, other merging procedure or high accurate object/sensor handling system. On the basis of this strategy different mobile and stationary arrangements are proposed and realized. A first integration in an industrial process will be presented showing the power of this concept by measuring the complete 3D shape of automotive parts and design objects within volume of 1dm3 up to 1m3. The measurements with this system showed a coordinate measurement accuracy of up to 10-5 of the field size.
The most frequently used drug for the fluorescent visualization and photosensitization of tumors is haematoporphyrin derivative (HpD). However, the mode of action of this sensitizer in vivo is not yet entirely understood. From the Photodynamic Therapy it is well known that their efficiency and selectivity increases with increasing amounts of oligomers/aggregates. The 'highly aggregated' HpD (Photofrin II) is also used in the fluorescence diagnostics. However, from the investigation of porphyrins it is known that the oligomers/aggregates fluorescent weakly compared with monomers. The monomers as well as linear chains of monomers (linear dimers and special forms of trimers) have longer fluorescence lifetimes and hence higher quantum yields required for effective fluorescence diagnostics. This discrepancy stimulates the studies of the interaction of HpD containing high concentrations of tumor localizing fraction with membranes and membrane like-structures. The interaction has been investigated by means of fluorescence (OMA-system) and absorption spectroscopy. The results obtained lead to the conclusion that the monomers form the aqueous phase and/or self-associated aggregates which are in equilibrium with the monomers are taken up by the membranes only to a small degree compared with chemically bound oligomers. On the other hand, oligomers are incubated and defolded, and this leads to an increasing amount of linear polymers/monomers in the membranes versus incubation time. This seems to be the dominating process in the fluorescent visualization of cells and tissue, including tumor tissue, when HpD, Photosan or other amphiphilic porphyrins are applied.
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