| 摘要 |
<p>There are disclosed variations on a basic technique for forming a diffusion or rear-projection screen comprising an array of microlenses formed by selective light exposure and consequent selective polymerisation of a sheet of photopolymerisable material. Thus, the lenses may be made elongate in a preferred direction transverse to the lens axes by exposure through a mesh formed with an array of slots. The lenses may be graded refractive index lenses having a surface relief adding to the lens power, such relief being formed naturally or by moulding. The photopolymerisable material may be exposed by laser light, for example to a holographic pattern and such exposure may be made through a quarter-wave plate continuously rotated to eliminate micro defects. Enhanced lens powers may be achieved by heating the photopolymerisable material to close to the softening temperature of the associated polymer before exposure to light and maintaining the material at that temperature during the resultant polymerisation.</p> |
