| 摘要 |
A surveillance device (100) includes a circuit card assembly (104) disposed in a housing (102) and a plurality of light emitting diodes (108; 202) disposed on the circuit card assembly (104), each of the plurality of light emitting diodes (108; 202) configured to emit a narrow beam of light. The surveillance device (100) further includes a diffuser (114; 204) disposed in the housing (102), the diffuser (114; 204) configured to spread the narrow beam of light and a Fresnel lens (112; 206) disposed in the housing (102), the Fresnel lens (112; 206) configured to spread and redirect light emitted from the diffuser (114; 204). |
