Optical microscope with a CCD-Camera system

This section describes the main setup that was built for particle positioning and manipulation measurements. As shown in figure 2.5, the setup consists of an optical microscope with an attached CCD-camera and an IC-socket that holds the sample. A computer is used to record the applied currents/voltages and the video images of the sample (see figure 2.5(b) for a close-up of the setup).

Figure 2.5: Setup used for the main measurements. Including an optical microscope with a CCD-camera, an IC-socket for the samples and a computer with proprietary developed software.

[Overview]     [Close-up]

The microscope is an AXIOTECH VARIO from ZEISS with 3 EPIPLAN objectives, with a magnification of 20$\times$, 50$\times$ and 100$\times$ and a 10$\times$ eyepiece. The sample holder is a self-made IC-socket, which is set on top of a micro precision positioning table from PARKER. All contacts of the IC-socket are connected via a special box to the measuring instruments, power supplies and an analog-digital converter card (CIO-DAS08-PGA) in the computer. Using a c-mount adapter, the CCD-camera M4+CL from JAI on top of the microscope is directly connected to a special video grabber card in the computer.

For a complete survey of the sample during the experiments, a computer program is developed that grabs images from the CCD-Camera, simultaneously measures voltages from the A-D card and saves the data together on the hard-disk. Because the magnetic field directly depends on the current through a conducting line, the voltage over a specified resistor is measured and directly converted into the current. For an easier review process and for better presentation of the collected data, another program was developed that takes the specified part of the images, adds the actual current/voltage inside the image and puts the single images together to a video. See the enclosed CD for the source code of both programs and examples of the videos.