Projection optical apparatus and image projection apparatus
A disclosed projection optical apparatus includes a plurality of lenses, each of the lenses having a flat surface in a part of an outer circumference; a lens holder having a hollow cylindrical shape and configured to hold the lenses; and a vent hole formed of gaps communicating between the flat surfaces of the lenses and the lens holder.
1. A projection optical apparatus comprising:
a plurality of lenses, each of the lenses having a flat surface in a part of an outer circumference;
a lens holder having a hollow cylindrical shape and configured to hold the lenses; and
a vent hole formed of gaps communicating between the flat surfaces of the lenses and the lens holder.
2. The projection optical apparatus as claimed in claim 1 , wherein the lenses are disposed such that the flat surfaces of the lenses are disposed parallel to one another on a same side of an optical axis.
3. The projection optical apparatus as claimed in claim 2 , wherein the lenses are disposed such that the flat surfaces of the lenses are positioned at different levels.
4. The projection optical apparatus as claimed in claim 1 , further comprising:
a radiator plate configured to be in contact with at least one of the flat surfaces of the lenses to radiate heat.
5. The projection optical apparatus as claimed in claim 4 , wherein at least one of the lenses includes a projection projecting from the radiator plate toward the vent hole.
6. The projection optical apparatus as claimed in claim 1 , further comprising:
a heat pipe configured to be in contact with at least one of the flat surfaces of the lenses to cool.
7. The projection optical apparatus as claimed in claim 1 , further comprising:
a blower configured to blow air into the vent hole.
8. The projection optical apparatus as claimed in claim 7 , further comprising:
a temperature detector attached to the lens holder; and
a controller configured to control an air volume of the blower based on a detected result of a temperature obtained by the temperature detector.
9. An image projection apparatus comprising the projection optical apparatus as claimed in claim 1 .
10. The image projection apparatus as claimed in claim 9 , further comprising:
a digital mirror device configured to modulate light emitted from a light source based on a projected display image to transmit the modulated light into the lenses.