application_number US 64172106 A description preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings first fig7 illustrates a configuration of a variable focus lens 100 according to an embodiment of the present invention the variable focus lens 100 includes a chamber wall 110 forming a cylindrical inner space with a first bump or protrusion 112 a second protrusion 114 and two third protrusions 115 formed on one end thereof an upper transparent plate 120 attached to an upper end 110 a of the chamber wall 110 with a predetermined interval g in between and a lower transparent plate 130 attached to a lower end 110 b of the chamber wall 110 here the first protrusion 112 has a rectangular section and each of the second and third protrusions 114 and 115 has an inverted triangular section thus three grooves are formed by the first protrusion 112 the second protrusion 114 and the third protrusion 115 at this time the upper transparent plate 120 and the chamber wall 110 are hermetically attached to each other via a sealing 122 and the lower transparent plate 130 and the chamber wall 110 are bonded with each other by a bonding layer not shown the bonding can be done for example by frit bonding alternatively the lower transparent plate 130 can be.