A lens assembly suitable for use in miniature cameras is disclosed. The lens assembly can have a plurality of glass lenses having spherical surfaces and a single plastic lens having aspheric surfaces, for example. Optionally, all of the lenses can be disposed within a common lens barrel. A pupil plane can be located just in front of the first lens to provide a small chief ray angle. Both the cost of the lens assembly and alignment sensitivity are advantageously mitigated.
1. A lens assembly for a miniature camera, the lens assembly comprising:
a plurality of lenses configured for use in an autofocus camera; wherein
the lenses are configured so as to define a pupil plane in front of a first lens thereof; and
the plurality of lenses are configured to move in unison.
2. The lens assembly as recited in claim 1 , wherein the pupil plane is disposed proximate a front of a first lens.
3. The lens assembly as recited in claim 1 , wherein the pupil plane defines a chief ray angle of less than 20 degrees.
4. The lens assembly as recited in claim 1 , wherein the plurality of lenses comprises four lenses.
5. The lens assembly as recited in claim 1 , wherein the plurality of lenses comprise a positive power first lens, a negative power second lens, a positive power third lens, and a fourth lens.
6. The lens assembly as recited in claim 1 , wherein the plurality of lenses comprise four lenses having lens parameters respectively corresponding to those listed in the tables of FIGS. 3 and 4 .
7. The lens assembly as recited in claim 1 , wherein the plurality of lenses are disposed within a common lens barrel.
8. The lens assembly as recited in claim 1 , wherein the plurality of lenses comprise three glass lenses and one plastic lens.
9. The lens assembly as recited in claim 1 , wherein the plurality of lenses comprise three spherical lenses and one aspheric lens.
10. The lens assembly as recited in claim 1 , wherein the last lens is an aspheric lens.
11. The lens assembly as recited in claim 1 , wherein the first three lenses are plastic lenses with spherical surfaces and the last lens is a glass lens with aspheric surfaces.
12. The lens assembly as recited in claim 1 , wherein the plurality of lenses are configured so as to focus light from 10 cm to infinity with a travel of less than 200 microns.
13. The lens assembly as recited in claim 1 , wherein the plurality of lenses are configured so as to focus light from 10 cm to infinity with a travel of approximately 180 microns.