Rod lens array and a process for producing the same

A process for producing a single-row rod lens array, comprising;

• a lens arranging step in which a grooved aligning tool having a multiple of shallow grooves formed parallel to each other at a constant pitch is supplied with a multiple of gradient index rod lenses such that they are placed in alignment with each other within said shallow grooves;
• a partial burial step in which an impregnating resin sheet and a frame are placed in a face-to-face relationship with the group of the thus arranged rod lens, then heat is applied to render said resin sheet viscous and pressure is also applied so that the individual rod lenses are bonded to the frame as they are partially buried in the resin and, thereafter, the bonded rod lenses are detached from said aligning tool;
• and
• a complete burial step in which an impregnating resin sheet and a frame are placed in a face-to-face relationship with the partially buried rod lenses in array form, then heat is applied to render said resin sheet viscous and pressure is also applied so that the individual rod lenses are bonded to the frame as they are buried completely in the resin;
• wherein a frame with a striped pattern of multiple ridges that extend along the rod lenses and that arranged on the same pitch as the rod lenses is used as the frame in the partial burial step or in both partial and complete burial steps, and the rod lenses are bonded to said frame such that each of them is located between adjacent ridges.

A process for producing a two-row rod lens array, comprising:

• a lens arranging step in which a grooved aligning tool having a multiple of shallow grooves formed parallel to each other at a constant pitch is supplied with a multiple of gradient index rod lenses such that they are placed in alignment with each other within said shallow grooves;
• a partial burial step in which an impregnating resin sheet and a frame are placed in a face-to-face relationship with the group of the thus arranged rod lenses, then heat is applied to render said resin sheet viscous and pressure is also applied so that the individual rod lenses are bonded to the frame as they are partially buried in the resin and, thereafter, the bonded rod lenses are detached from said aligning tool;
• and
• a complete burial step in which an impregnating resin sheet is placed between two arrays of the partially buried rod lenses such that the rod lenses in one array are in a face-to-face relationship with those in the other array, then heat is applied to render said resin sheet viscous and pressure is also applied so that the individual rod lenses are bonded between the frames as they are buried completely in the resin;
• wherein a frame with a striped pattern of multiple ridges that extend along the rod lenses and that arranged on the same pitch as the rod lenses is used as the frame in the partial burial step and the rod lenses are bonded to said frame such that each of them is located between adjacent ridges.