Marko Pudas

Gravure offset printing development for fine line thick film circuits

The resolution of conventional graphical gravures is limited to about 50 to 100 microns depending on the technology used. For these gravures the depths are dependent on the widths of the grooves. For electrical circuitry, the target is to achieve 25 microns line and space widths in the near future. To obtain a reasonably high sheet resistance, the printed ink height must be reasonably high. The stated requirements require further development of the whole printing process together with the associated inks. The first step was to evaluate the gravure manufacturing method, which is capable of producing gravures of sufficient accuracy and uniform depth. In this paper a new gravure printing plate manufacturing method with high accuracy is presented. Printing results made with the manufactured gravure and tailored inks are reported.

Roller-type gravure offset printing of conductive inks for high-resolution printing on ceramic substrates

The use of gravure offset printing methods at an industrial level requires a wide and deep knowledge of the printing properties of the inks. Novel hydrocarbon inks were developed with superior printing properties compared to alternative ethyl cellulose-based inks. There are principal behaviour properties of these inks that can be generally described. In particular, the resistance dependence of printed mass for single and multiprints and on the other hand, the effect of multiprinting on printed area smoothness and line height. This article summarizes the results obtained and describes printing properties and defects: line widening, hair formation, ink flow from the gravure grooves, pinholes, image distortions, ribbing, scooping, streaking and gravure groove blocking. Three different printed samples were demonstrated, which are best suited for this manufacturing method: interdigital capacitor, inductor coil and laser soldering substrates.

First example of one-pot synthesis of hydrocarbon macrorings

Cyclomagnesation of α,ω-diallenes by EtMgBr in the presence of chemically activated Mg and Cp2TiCl2 catalyst led to the formation of cyclic organomagnesium compounds whose hydrolysis provided gigantic hydrocarbon macrorings with 1,5-cis-disubstituted double bonds.

Catalytic [2+1]-cycloaddition of ethyl diazoacetate to fullerene [60]

Cyclopropanation of C60-fullerene was performed with ethyl diazoacetate in the presence of Pd(PPh3)4 catalyst. A probable reaction mechanism is suggested.

Catalytic hydroamination of fullerene C60 with primary and secondary amines

Catalytic 1,2-hydroamination of fullerene C60 with primary and secondary amines in the presence of Ti, Zr, and Hf complexes gave the corresponding alkyl-, aryl-, and hetarylaminodihydrofullerenes.

Traceable characterization of a bending millimetre scale cantilever for nanoforce sensing

We have developed and characterized a force measuring system that is able to measure small forces down to 50 nN. The force measuring system and the characterizing method are described, thoroughly tested and analysed. The force measuring system consists of a linear positioner, a bending cantilever and an optical detection system for detecting the bending of the cantilever displacement. Characterization was carried out with a microbalance and a laser interferometer. The characterized measurement range of the system is from 50 nN to 1.5 mN. The performance of the system is limited by the linearity of the positioner and the noise of the optical sensor detecting the cantilever bending. The characterization system was found to be adequate for force sensors in the nanonewton range. The results are traceable to mass and acceleration of gravity, which makes the measurements reliable and comparable to other force measurements and applications.

A minimally invasive displacement sensor for measuring brain micromotion in 3D with nanometer scale resolution

Electrophysiological recordings from a single or population of neurons are currently the standard method for investigating neural mechanisms with high spatio-temporal resolution. It is often difficult or even impossible to obtain stable recordings because of brain movements generated by the cardiac and respiratory functions and/or motor activity. An alternative approach to extensive surgical procedures aimed to reduce these movements would be to develop a control system capable of compensating the relative movement between the recording site and the electrode. As a first step towards such a system, an accurate method capable of measuring brain micromotion, preferably in 3D, in a non-invasive manner is required. A wide variety of technical solutions exist for displacement measurement. However, increased sensitivity in the measurement is often accompanied by strict limitations to sensor handling, implementation and external environment. In addition, majority of the current methods are limited to measurement along only one axis. We present a novel, minimally invasive, 3D displacement sensor with displacement resolution exceeding 70 nm along each axis. The sensor is based on optoelectronic detection of movements of a spring-like element with three degrees of freedom. It is remarkably compact with needle-like probe and can be packaged to withstand considerable mishandling, which allow easy implementation to existing measurement systems. We quantify the sensor performance and demonstrate its capabilities with an in vivo measurement of blowfly brain micromotion in a preparation commonly used for electrophysiology.

Cycloaddition of tertiary amines to fullerene C60, catalyzed by Ti, Zr, and Hf complexes

Cycloaddition of various tertiary amines to fullerene C60 in the presence of Cp2MCl2 complexes (M = Ti, Zr, Hf) in toluene at 20–150°C in 3–48 h leads to the formation of pyrrolofullerenes in high yields.

Surface charge detection probe

This paper presents a low-cost contact mode surface charge probe that consists of an integrating IC, its control electronics and a metal probe. A microcontroller is used to control the probe and to A/D convert its analog output voltage. The measured object is moved by a translation stage that consists of three linear piezoactuators which are controlled by microcontrollers. The probe is calibrated by discharging a calibration capacitor into its input. The probe is used to scan the surface of an insulating material such as paper. The scans are done in normal air pressure. Charge transfer is found to occur due to both contact and break of the contact between the metal and the insulator. It is suspected that the frictional contact between the surface and the probe tip also cause charge transfer as well as charge differences on the insulator surface. Scan results from a paper surface are presented. The minimum detectable charge with the probe is approximately 100 fC.

Different micromanipulation applications based on common modular control architecture

This paper validates a previously introduced scalable modular control architecture and shows how it can be used to implement research equipment. The validation is conducted by presenting different kinds of micromanipulation applications that use the architecture. Conditions of the micro-world are very different from those of the macro-world. Adhesive forces are significant compared to gravitational forces when micro-scale objects are manipulated. Manipulation is mainly conducted by automatic control relying on haptic feedback provided by force sensors. The validated architecture is a hierarchical layered hybrid architecture, including a reactive layer and a planner layer. The implementation of the architecture is modular, and the architecture has a lot in common with open architectures. Further, the architecture is extensible, scalable, portable and it enables reuse of modules. These are the qualities that we validate in this paper. To demonstrate the claimed features, we present different applications that require special control in micrometer, millimeter and centimeter scales. These applications include a device that measures cell adhesion, a device that examines properties of thin films, a device that measures adhesion of micro fibers and a device that examines properties of submerged gel produced by bacteria. Finally, we analyze how the architecture is used in these applications.