Abstract: A containment structure with three sides and a triangular end is collapsible to a significantly smaller profile for ease in storage and transportation, yet keeps all major sections connected. Unique means of folds and hinging provide these advantages. Special applications (oriented upright or lying horizontal) from cleanup of lawn debris to emergency shelter of personnel and instruments can utilize the compact storage, ease of transport, quick setup, and shape advantages of the containment structure.

Abstract: The invention improves on an ocular having at least one spatially modulating, reflective device at one of the possible locations of an intermediate image plane. Emphasis is on the ocular containing the reflective device, rather than that device's function. A list of device functions include nonlinear image light modulation; optical power limiting; planar image processing; reticle, grid or text superposition. All such functions require sharp image focus on the device surface plane. A polarizing beamsplitter, quarter-wave plate means, field lens and roof prism are combined to simultaneously improve optical energy efficiency, sharpen focus and reduce keystoning at the reflective device while increasing the field-of-view for the virtual image of observed scenery.

Abstract: A real-time, optical, nonlinear attenuator device situated in the image plane of an ocular of special construction provides a highly sensitive, broad spectral band, selective, glare reduction ocular. This system is suitable for the eye or camera which is directed at scenery with illumination ranging from that of a room interior to outside daylight. Special adaptations from spatial light modulator technology and modifications of optical power limiter art increase the nonlinear attenuator device sensitivity to bright light by orders of magnitude over that in current systems using known passive, optical, nonlinear materials. The ocular concept includes an input lens which gathers more light rays than can pass to the eye in order to further enhance nonlinear sensitivity, contains places for filters, operates with either an absorption-promoting or scattering nonlinear device in the intermediate image plane, corrects image inversion and provides embodiments for transmissive or reflective operation.