Abstract: A top bedsheet, bottom (fitted contour) bedsheet, or pillow case is produced by circularly knitting, in a jersey knit configuration, a sheath and core yarn into a fabric. The sheath fibers comprise short staple fibers such as cotton or comparable cellulosic fibers, and provide at least 50 percent of the yarn and preferably about 68-83 percent of the yarn. The core fibers are long staple synthetic fibers such as polyester, and are completely covered by the cotton so that the product has smoothness of hand. The fabric has a weight of approximately four ounces per square yard, and is finished so that it has a relaxed shrinkage of about five percent in both the length and width dimensions. The sheath and core yarn configuration is produced by passing a sliver of sheath fibers and a roving of core fibers through a trumpet, and then through the rear rolls, apron, and front rolls of a drafting apparatus to produce a drafted composite sliver, and then mechanically imparting a twist to the drafted composite sliver.

Abstract: An aplanatic image combiner. At least two image generating cathode ray tubes are provided having curved concave phosphor image generating surfaces. A set of dichroic mirrors are provided to combine images from each of the curved surfaces into a single combined image. A lens is positioned to transmit the combined image to an image magnification system. The lens has a curved surface forming an exit aperture for the image combiner. The radius of curvature of the lens is configured to be substantially the same as the radius of curvature of each of the concave image generating surfaces of the cathode ray tube. An image is generated to an image magnification system without generating any field aberration or astigmatic and chromatic aberration requiring correction in the magnification system.

Abstract: A lens construction for a character projection unit and with the character projection unit including a plurality of light sources mounted in side-by-side relation, a plurality of corresponding condensor lenses, a plurality of corresponding projection lenses, and a plurality of corresponding characters disposed between the light sources and projection lenses to form a number of separate and individually complete projection systems within a confined volume, including at least one condensing lens plate in which is formed the plurality of individual condensing lenses, at least one projection lens plate in which is formed the plurality of individual projection lenses, and each of the complete projection systems including one of the individual condensing lenses formed in the condensor lens plate and the corresponding one of the individual projection lenses formed in the projection lens plate and with at least one of the lens surfaces of each of the complete projection systems formed as an aspheric surface whereby t

Abstract: A light mixing device of optically clear light transmitting material where the various color components of light introduced in the input end of the device are efficiently mixed by internal reflection through the length of the mixer. The mixer may be either linear or curved and includes axially extending reflective surfaces internal of its outer periphery.

Abstract: An optica image forming screen which comprises a multiplicity of light-transmitting elements in a matrix of light-absorbing elements so that light incident upon the elements at an angle greater than a predetermined angle will be internally absorbed by the elements, with no significant reflection internal to the elements and with element size conducive to a scattering effect by using diffraction in the image space.

Abstract: A camera of the so-called pocket type having an objective lens including means for varying the equivalent focal length. The optical axis of the overall lens is folded to have two forward portions and a connecting lateral portion with the primary zooming elements on the lateral portion. The view finder system axis is a linear continuation of the lateral objective axis.

Abstract: A lens of five elements comprising a first bi-convex element, a second meniscus element, a third bi-concave element, a fourth meniscus element, and a fifth bi-convex element with an aperture stop between the meniscuses and the concave surfaces of the meniscuses facing the aperture.

Abstract: A light detecting system for a single lens reflex camera in which an image of the focusing screen is reflected to the normally unused surface of the pentaprism from a partially reflective surface in the viewfinder system. The reflective surface in one form may be glass-to-air interfaces on the viewfinder axis in the eyepiece, but also may be a thin partially reflecting coating.

Abstract: A viewfinder system for a through-the-lens viewing camera which includes a focusing screen, a field lens, a prism, and an eyepiece is disclosed where the field lens is positionable in accordance with the position of the exit pupil of the objective lens and the eyepiece is positioned in accordance with the position of the field lens. Negative optical power is introduced between the field lens and the prism, and the prism design substantially reduces the size of the prism without sacrificing viewfinder brightness.

Abstract: A viewfinder system for a single lens reflex camera where the field lens of the system is positionable in accordance with the distance of the objective lens exit pupil from the focal plane and eyepiece lenses are positionable in accordance with the field lens to maintain uniform viewfinder brightness without any essential change in image magnification.