Patent ID: 8189123

Claim:
A projection apparatus with a light modulator having a light receiving region with a cross-sectional area to be illuminated of the size A M and a maximum acceptance angle α for incident light, and at least one light source by means of which, during its operation, a light cone is produced for illuminating said cross-sectional area of said light receiving region and which comprises a number N of LED chips having a radiation decoupling area of the size A D and a maximum radiation angle β, characterized in that at least one optical element is disposed in a light path between said LED chips and said light modulator, a gap filled with a gas is present in the light path between said LED chips and said optical element, and 0.7·(A M ·sin 2 (α))/( A D ·sin 2 (β)·n 2 )≦N≦1.3·(A M ·sin 2 (α))/(A D ·sin 2 (β)·n 2 ), where if said radiation decoupling area A D of said LED chips is free of a coupling medium, then n=1, and if said radiation decoupling area A D of said LED chips is provided with a coupling medium, then n is equal to the refractive index of a material of the coupling medium.