| 摘要 |
Collimated visual display apparatus comprising an aspheric screen ( 12 ) and a curved collimating mirror ( 16 ), characterised in that the aspheric screen ( 12 ) is not a surface of revolution about an axis, the aspheric screen ( 12 ) comprises first and second parts ( 6, 8 ) which are separated from each other by a third part ( 10 ), the first and second parts ( 6, 8 ) are curved in cross section and if connected together then they would form a surface of revolution, the third part ( 10 ) is straight in cross sectional view and is a short cylindrical centre section, and the collimated visual display apparatus is such that the aspheric screen ( 12 ) has an outer curved surface that is viewed via the curved collimating mirror ( 16 ) by a user of the collimated visual display apparatus.
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