| 摘要 |
A plotting implement for creating a record on a photosensitive surface. The plotting implement includes a contact tip for contacting and for moving between different positions on the surface, the contact tip in use constituting an electromagnetic radiation source located at the surface, whereby the radiation source at the tip exposes points and/or lines of contact of the tip with the surface. The contact tip has a radiation aperture of a predetermined diameter to expose lines of a width equal to that diameter. An optic fibre of the required diameter may extend from an electromagnetic radiation source and terminate at the aperture. Alternatively the electromagnetic radiation source may comprise a light emitting diode (LED) having a transparent body tapering from the source of light towards the tip, the tapering body being surrounded by opaque material and being truncated before reaching a point to provide a tip of the transparent body of the predetermined diameter. The specification also describes a plotting apparatus including a plotting implement, mounted so as to bring the contact tip into contact with the surface and driven so as to control the relative movement of the plotting implement by an associated computer.
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