Varifocal lens

A varifocal lens, comprising a housing section, a first elastic membrane, a first medium, a second medium, a drive section, and a first tensile force applying section, wherein:

• the housing section is capable of passing light along an optical axis direction of a lens, and the housing section comprises a first space and a second space arranged along the optical axis direction,
• the first elastic membrane is arranged between the first space and the second space, and is configured to partition between the first space and the second space by extending in a direction that intersects the optical axis direction,
• the first medium is filled into the first space,
• the second medium is filled into the second space,
• refractive indices of the first medium and the second medium are respectively different,
• the first elastic membrane is arranged between the first medium and the second medium, and the first elastic membrane is capable of being elastically deformed by a pressure difference between the first medium and the second medium,
• the drive section is configured to change a curvature of the first elastic membrane by causing a variation in pressure or volume of the first medium or the second medium, and
• the first tensile force applying section applies isotropic tensile force to the first elastic membrane.