Patent ID: 7123316

Claim:
A reflective cover, comprising: at least one reflective unit comprising two reflective surfaces defining a space with a bottom for accommodating a light source, a cross-sectional profile of the reflective surfaces being defined by an equation in a polar coordinate ρ(φ): { ∫ π / 2 φ - θ ⁢ ρ ⁡ ( φ ) ⁢ sin ⁡ ( φ - θ ) ⁢ ⅆ ( φ - θ ) = ∫ 0 θ ⁢ 1 cos 2 ⁡ ( θ ) ⁢ ⅆ θ ρ ⁡ ( φ ) = ρ 0 ⁢ { cos ⁡ ( θ / 2 ) / [ cos ⁡ ( φ - θ ) / 2 ] } 2 , wherein, ρ represents a polar axis of the polar coordinate, φ represents a clockwise angle of the polar coordinate, and θ represents an anti-clockwise divergence angle of light emitted from the light source.