We have explored a new family of 6 mm imaging endoscope designs for laparoscopes. These designs use a `solid' relay lens made up of plastic lens components bonded together in a repetitive fashion to form a long, monolithic relay element without air spaces. The lack of air spaces allows for the elimination of coatings and spacing elements. This simplifies construction and should considerably lessen cost. A four element objective lens is presented for the system which uses a plano-convex sapphire element as a combination window and lens element. The other three lens elements are plastic, and produce an image which is `buried' in the monolithic relay. Two designs are discussed, a relatively inexpensive, `single use' design, which incorporates easy-to-fabricate, low-temperature plastic lens elements, and a more expensive, `autoclavable' design, using high-temperature plastic lens elements. Both designs exhibit good optical resolution, and high optical throughput and contrast.
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