Composite lens system, and lens unit provided with such composite lens system, as well as image pickup device provided with such lens unit

A composite lens system comprising a plurality of lenses which are disposed adjacent one another in a direction of their optical axes aligned with one another by an axis-aligning adjustment, wherein

• adjacent two of said plurality of lenses have optically non-functioning faces which are formed thereon to abut against each other directly or with another member interposed therebetween, whereby the positioning of said adjacent lenses in the direction of the optical axes is achieved, and said plurality of lenses have adjusting faces which are formed thereon, so that angles formed by said adjacent lenses with respect to the optical axes are different from each other, and which are used for an axis-aligning adjustment for said adjacent lenses, said axis-aligning adjustment being achieved by an adjusting member disposed to engage both the adjusting faces of said adjacent lenses;
• and
• one of said adjacent lenses has a plurality of extensions formed thereon outside its optically functioning face at predetermined distances circumferentially from one another to extend toward the other of said adjacent lenses along the optical axis;
• adjusting faces of said one lens are formed on outer peripheral surfaces of these extensions;
• a plurality of projecting edges are formed on said other lens outside its optically functioning face and each located between the adjacent extensions of said one lens;
• adjusting faces of said other lens are formed around outer peripheral surfaces of said projecting edges;
• and said adjusting member is fitted around outer peripheral surfaces of the adjusting faces of said one lens and the adjusting faces of said other lens.