This paper presents a novel method to fabricate temperature sensor arrays by dispensing a graphite-polydimethylsiloxane composite on flexible polyimide films. The fabricated temperature sensor array has 64 sensing cells in a 4 × 4 cm2 area. The sensor array can be used as humanoid artificial skin for sensation system of robots. Interdigitated copper electrodes were patterned on the flexible polyimide substrate for determining the resistivity change of the composites subjected to ambient temperature variations. Polydimethylsiloxane was used as the matrix. Composites of different graphite volume fractions for large dynamic range from 30 °C to 110 °C have been investigated. Our experiments showed that graphite powder provided the composite high temperature sensitivity. The fabricated temperature sensor array has been tested. The detected temperature contours are in good agreement with the shapes and magnitudes of different heat sources.

No abstract

No abstract

No abstract

In this research, a low-cost and precision autofocus laser probe system was developed. Modified from the pickup head of a commercially available DVD as a basis, it can detect the focus error signal (FES) of the object with a built-in four-quadrant photodiode. The FES will feed back to the developed controller, through which the objective lens can be adjusted in position automatically to remain in focus, driven by a voice coil motor (VCM). The driving current (converted from servo-FES) of the VCM and the objective lens displacement are one to one linearly related within several hundred micrometres. Because of this relationship, the surface profile and the surface roughness of the tested object can be realized. Calibrated results showed that the designed probe has 200 µm linearity range, 0.2 µm accuracy, 0.1 µm resolution and standard deviation of 0.2 µm on average. Some examples are given to show the applicability of this probe system.

No abstract

A high-precision and low-cost micro-CMM (coordinate measuring machine) is under development. The expected measuring range is 25 × 25 × 10 mm 3 and the resolution is 1 nm. In order to enhance the structural accuracy, some new ideas are integrated into the design, such as the arch-shape bridge for better stiffness and thermal accuracy, and the co-planar stage for less Abbe error. The linear diffraction grating interferometer and subdivision technique is proposed for position sensing to nanometre resolution. The focusing probe on the laser interferometer feedback spindle is structured in the Z-axis to guarantee the nanometre stability. In this report, the detailed design principles of the developed micro-CMM are described. The performance evaluation of each module of the prototype micro-CMM is presented. The positioning resolution of each axis to 1 nm can be achieved by combining the coarse and fine motion control on a piezo-ceramic linear motor. The Z-axis measurement can be controlled to within 15 nm repeatability. Parts of the positioning repeatability of the co-planar stage have been achieved to 30 nm. Some problems due to current techniques will be addressed.

A high-precision optical probe based on the principle of focusing-range detection is developed in this research. The probe adopted for use was directly taken from the pickup head of a CD player. Because its principle is similar to that of the autofocusing probe, the characteristics of each component of the head were investigated and its conversion into a focusing probe was attempted. The S-curve within the focusing range can be analysed, revealing the linear relationship between the normalized focus-error signal (FES) and the measured distance. The system accuracy of the probe was found. Within the measurement range of 10 µm the linearity error was about 1%, the standard deviation was about 34 nm and the frequency response was about 8 kHz. Some practical applications were carried out, namely profile measurements of a step height, a CD surface and a silicon-wafer grating. All results were highly consistent with the nominal values.