A universal shelter frame for attaching to a primary spectacle frame having two primary lenses mounted thereon, wherein the universal shelter frame includes a pair of shelter lenses each having an inner side facing with each other, a pair of connecting members which are affixed to the two inner sides of the two shelter lenses respectively, and an adjustable bridge arrangement connected between the two shelter lenses together for supporting the two shelter lenses apart and forming a bridge distance between the two shelter lenses. The adjustable bridge arrangement includes at least one compression unit for enabling the adjustable bridge arrangement to be compressed to contract the bridge distance in order to mount the shelter frame on the primary spectacle frame by attaching the two connecting members to two inner edges of the primary lenses of the primary spectacle frame respectively. Therefore, the user can easily attach the universal shelter frame to the primary spectacle frame with one hand, even when the primary spectacle frame is still wearing on the user's face.

The method for exposing a printing plate copies a stored model onto a printing plate. The exposure device includes at least one exposure head (1). Each exposure head (1) has a light source (3), a picture generating unit (8) and a copying optical element (9). The picture generating unit (8) includes electronically controllable micro mirrors arranged in a grid. The stored model is divided into partial images, which are shown in succession by the picture generating unit (8) and the copying optical element (9). Successive partial exposures of the printing plate are made by the at least one exposure head, which is accurately positioned at respective successive exposure positions by an electric linear drive so that individual copies of the partial images are combined into a total image on the printing plate with a position accuracy of better than 5 microns. Exposure times are shortened while maintaining copy quality.

A clip-on glasses assembly for mounting on primary glasses, comprising a pair of lens members, at least one grapple on each of the pair of lens members for engaging the outer edges of the primary glasses, and a bridge between the lens members configured to slidably receive the lens members to allow movement of the lens members between an open position and a closed position. An actuator bar having two ends, each end coupled to one of the lens members, allows a user to easily mount and remove the glasses assembly using only one hand. Moving the actuator bar toward the bridge forces the ends of the actuator bar apart and moves the lens members into the open position. The actuator bar is generally U-shaped and constructed from a resilient material. The actuator bar and/or separate springs bias the lens member toward the closed position. The bridge may further comprise a locking mechanism to maintain the lens members in the open position. An actuating mechanism comprising just the actuator bar can be affixed to other glasses assemblies to make those assemblies operable using only one hand.

The lens sections of the sunglasses are joined by a spring mechanism. The mechanism includes first and second concentric tubular members. Each member is affixed to the rim of a different one of the lens sections. The members enclose the spring which urges the lens sections toward each other, such that prongs mounted on the rims can engage an eyeglasses frame to mount the sunglasses thereon.

The eyeglasses frame is provided with spaced engaging parts. The lens sections of the sunglasses are provided with an enclosed spring bridge mechanism that permits the lens sections to be moved toward each other, compressing the spring, to insert the sunglasses between the engaging parts. The spring urges the lens sections away from each other, to cooperate with the engaging parts, to mount the sunglasses on the eyeglasses frame.