▎ 摘　　要

NOVELTY - Transmission structure has multiple first transmission units (100) and multiple second transmission units (200) arranged disorderly in one surface. An electromagnetic wave incident surface of first- and second transmission units forms an electromagnetic wave incident surface of the transmission structure. First transmission unit is provided with first substrate (110) provided with first medium block (220). The thickness of first substrate between first medium block and the electromagnetic wave incident surface of first transmission unit is non-zero first thickness. Second transmission unit has second substrate (210). Second dielectric block is arranged inside second substrate. The thickness of second substrate between second medium block and electromagnetic wave incident surface of second transmission unit is non-zero second thickness. Second thickness is different from first thickness. First reflection phase and second reflection phase meet within preset frequency band. USE - The transmission structure is useful in film, screen and glass e.g. windshield of vehicles (all claimed). ADVANTAGE - The method configures second thickness and first thickness so that the first transmission unit and the second transmission unit can have a larger reflected electromagnetic wave phase difference in a wider frequency range. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: a method for preparing the transmission structure; and a projection system. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the two transmission units. 100First transmission unit 110First substrate 120First dielectric block 200Second transmission unit 210Second substrate 220Second medium block