| 摘要 |
A flat transparent envelope has a rectangular, transparent cover sheet and a rectangular, preferably transparent backsheet. The cover sheet and backsheet are preferably flexible films that are joined together along at least two but no more than three of the sheet edges so that the envelope is open along at least one of the sheet edges and the edges of the joined sheets are situated in the envelope plane. The transparent cover sheet and backsheet may advantageously be entirely formed of a magnifying material.
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