Patent ID: 11899170
Assignee: YOUNG OPTICS INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 13:
14. A projection apparatus, comprising:
a light source;
a light valve disposed downstream from and in a light path of the light source; and
an optical lens disposed downstream from and in a light path of the light valve, the optical lens consisting essentially of a first lens, a second lens, and a third lens arranged in order in a direction, the second lens having at least one diffractive optical surface, the first lens, the second lens and the third lens being aspheric lenses and made of plastic, and a total number of lenses with refractive powers in the optical lens being smaller than six, wherein a depth of the at least one diffractive optical surface is in the range of 0.29 um-2.5 um, and the projection apparatus is configured for projecting a real image.