Optical imaging system
An optical imaging system includes a plurality of fixed lenses disposed along an optical axis; a first reflective member disposed on an object side of the plurality of lenses; and a plurality of reflective members disposed on an image side of the plurality of lenses. At least one of the plurality of lenses is a variable lens having a variable focal length, and each of the plurality of reflective members is configured to move as the focal length of the variable lens changes.
1. An optical imaging system, comprising:
a plurality of fixed lenses disposed along an optical axis;
a first reflective member disposed on an object side of the plurality of lenses; and
a plurality of reflective members disposed on an image side of the plurality of lenses,
wherein at least one of the plurality of lenses is a variable lens having a variable focal length,
wherein each of the plurality of reflective members disposed on the image side of the plurality of lenses is configured to move as the focal length of the variable lens changes,
wherein −7<(fv_1×D6R_2)/(fv_2×D6R_1)<−1, where fv_1 is a first focal length of the variable lens, fv_2 is a second focal length of the variable lens, D6R_1 is a distance on an optical axis from a rearmost lens of the plurality of lenses to a reflective member most adjacent to the rearmost lens among the plurality of reflective members when the variable lens has the first focal length, and D6R_2 is a distance on an optical axis from the rearmost lens to the reflective member most adjacent to the rearmost lens when the variable lens has the second focal length,
wherein the plurality of lenses includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens disposed in order from the object side,
wherein the first to sixth lenses are spaced apart from each other along the optical axis,
wherein the optical imaging system has a total of six lenses, and
wherein the first lens has positive refractive power and a concave object-side surface in a paraxial region thereof.
2. The optical imaging system of claim 1 ,
wherein the variable lens is configured to have a first focal length or a second focal length as the focal length changes, and
wherein the first focal length is positive and the second focal length is negative.
3. The optical imaging system of claim 1 , wherein the variable lens comprises a liquid lens and a flat lens attached to an image-side surface of the liquid lens.
4. The optical imaging system of claim 3 , wherein a radius of curvature of an object-side surface of the liquid lens is variable and a thickness on an optical axis of the liquid lens is variable.
5. The optical imaging system of claim 4 ,
wherein the variable lens is configured to have a first focal length or a second focal length as the focal length changes, the first focal length is positive, and the second focal length is negative,
wherein, when the variable lens has the first focal length, the radius of curvature of the object-side surface of the liquid lens is positive,
wherein, when the variable lens has the second focal length, the radius of curvature of the object-side surface of the liquid lens is negative, and
wherein the thickness on the optical axis of the liquid lens is smaller when the variable lens has the second focal length than when the variable lens has the first focal length.
6. The optical imaging system of claim 1 ,
wherein the variable lens is the second lens or the sixth lens.
7. The optical imaging system of claim 1 ,
wherein the variable lens is the second lens, and
wherein the second lens has positive or negative refractive power, the third lens has negative refractive power, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and the sixth lens has positive refractive power.
8. The optical imaging system of claim 1 ,
wherein the variable lens is the sixth lens, and
wherein the second lens has negative refractive power, the third lens has positive refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, and the sixth lens has positive or negative refractive power.
9. The optical imaging system of claim 1 ,
wherein the plurality of reflective members includes a second reflective member and a third reflective member, and
wherein the second reflective member comprises a reflective surface configured to reflect light in a direction perpendicular to an optical axis of the plurality of lenses, and the third reflective member comprises a reflective surface configured to reflect light reflected by the second reflective member in a direction parallel to the optical axis of the plurality of lenses.
10. The optical imaging system of claim 9 , wherein the second reflective member and the third reflective member are configured to move together.
11. The optical imaging system of claim 1 , wherein 10<fv_1/D6R_1.
12. The optical imaging system of claim 1 , wherein-15<fv_2/D6R_2<−3.
13. The optical imaging system of claim 1 , wherein −3<fv_2/fv_1<0.
14. The optical imaging system of claim 1 ,
wherein 3<D6R_2/D6R_1<6, and
wherein the first focal length is positive and the second focal length is negative.
15. The optical imaging system of claim 1 , wherein 0<L1/TTL1<1, where L1 is a linear distance in a direction parallel to an optical axis from the object-side surface of the first lens to an imaging surface when the variable lens has a first focal length, and TTL1 is a distance on the optical axis from the object-side surface of the first lens to the imaging surface when the variable lens has the first focal length.
16. The optical imaging system of claim 1 , wherein 0<L2/TTL2<1, where L1 is a linear distance in a direction parallel to an optical axis from the object-side surface of the first lens to an imaging surface when the variable lens has a second focal length, and TTL2 is a distance on the optical axis from the object-side surface of the first lens to the imaging surface when the variable lens has the second focal length.
17. The optical imaging system of claim 1 , wherein 1< (L1×TTL2)/(L2×TTL1)<3, where L1 is a linear distance in a direction parallel to an optical axis from the object-side surface of the first lens to an imaging surface when the variable lens has a first focal length, L2 is a linear distance in the direction parallel to the optical axis from the object-side surface of the first lens to the imaging surface when the variable lens has a second focal length, TTL1 is a distance on the optical axis from the object-side surface of the first lens to the imaging surface when the variable lens has the first focal length, and TTL2 is a distance on the optical axis from the object-side surface of the first lens to the imaging surface when the variable lens has the second focal length.