Abstract: A image magnifier for the vision impaired which magnifies the image of face up source material (13) placed in the visual field of the camera (15) and displays the magnified image on a display (20). One embodiment includes a static high-resolution image mode and a second live video mode. The controller (29) provides different lighting appropriate for each mode. In a further embodiment the magnifier is transportable. Each part (17, 14, 16) is hinged (18, 19) to the other parts (17, 14, 16) allowing it to be folded into a compact lightweight form to be portably carried. In a still further embodiment the magnifier includes shielding for the lighting to minimise or avoid specular reflections.

Abstract: An infrared gas analyser. The analyser comprises a sample cell located in a gas flow, a source of infrared radiation of selected wavelengths which is propagated through the sample cell and an infrared detector which receives radiation which has passed through the cell, The radiation incident on the detector provides a measure of the concentration of selected substances in the gas flow due to one of the wavelengths being selected to be absorbed by the gas being measured. One preferred use is as a humidity sensor in a medical respiratory circuit where at least one selected wavelength is a wavelength strongly absorbed by water. Heating means am associated with the sample cell to vaporize any liquid water which may enter it and the cell is provided with internal baffles to reduce deposition or condensation of water on internal surfaces through which infrared radiation must pass.