Patent ID: 8687287

Claim:
A projection apparatus used to project an image on a projection screen, the projection apparatus comprising: an image generation device, used to project a light with the image, the image generation device having alight valve, and the light emitting out from the light valve; and a projection lens, disposed between the light valve and the projection screen, the projection lens comprising: a plurality of lenses, having an optic axis, the light passing through the lenses and being projected on the projection screen to generate a projection image, wherein the lenses comprises a first lens, a second lens, and a third lens, and the first lens, the second lens and the third lens are aspherical lenses; wherein the lenses satisfy a first relationship expressed by: 14 mmâ‰¦(EFL+N)â‰¦=17 mm, and a second relationship expressed by: 5 mmâ‰¦EFLâ‰¦8 mm, wherein EFL is an effective focal length of the projection lens, and N is a number of the lenses.