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The optical system design requirements then are reduced to causing the parallel rays from the ghost image generating element to pass through that point. As shown in FIGS. The rays marked E come to a focus at P E coincident with the retina, and form a small focused dot 20, centered in the circle if the eye is correctly positioned.
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The manner of generation and appearance of a single defocussed dot is shown in greater detail in FIGS. The dot acts as a pinhole camera, imaging the light source, defined by the iris 46 of the viewer's eye as its outside limit and by the LED chip's solder pad as its inside feature. In general, the defocussed image is annular, with the outer edge jagged, as is the inner edge of the viewer's iris. Irregular shaped pupils, astigmatism, etc.
The manner in which this is done, independently of optical aberrations due to any optical defects which may characterize the eye of the viewer, is further illustrated in FIGS.
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In these figures, FIG. In these views, the images or dots 20 which are in focus are represented by small circles; those which are out of focus 20a by large circles. When the optical system is used by a myopic viewer, the situation is as illustrated in FIG. The peripheral views of that figure indicate viewer head position in which the line of sight is not aligned with the optical axis of the instrument, in the directions indicated by the axes of the concentric circles. When the head position is such that the line of sight is exactly on the optical axis of the instrument, the condition illustrated in the central figure obtains: i.
As is evident from a consideration of FIGS. In summary, the image alignment system of my invention is a simple but effective device to provide for the viewer of an optical system a series of visible dots that are distributed along the line of sight such that, regardless of the viewer's spherical refractive error corrected or not , at least one of the dots will be sufficiently in focus to provide a well-defined fixation target, without the need for adjustable focusing mechanisms. In a representative implementation of the presently described device, the nearest dot is in sharp focus for an extremely near-sighted viewer with a refractive error of minus eight diopters.
US3698823A - Attitude indicating instrument - Google Patents
There is no limit to the most distant dots except that they become increasingly fainter, with usable dots extending beyond what would be in sharp focus for a far-sighted viewer with a refractive error of plus twenty diopters. In the use of a light source with a dark center, such as the above described solder pad on an LED chip, there result out-of-focus dots also having dark centers.
This permits the smaller images of the more-in-focus dots to be more easily seen and fixated on. The overall pattern takes on the appearance of a "bulls-eye" when the eye is correctly positioned, with the fixation point at the center of the concentric circles. The viewer's procedure is obvious intuitively, even to the technologically naive.
Having thus described in detail a preferred embodiment of the present invention, it will be apparent to those skilled in the art that various physical changes could be made in the device described herein without altering the inventive concepts and principles embodied. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein.
All rights reserved. A SumoBrain Solutions Company. Login Sign up. Search Expert Search Quick Search. Optical alignment system. United States Patent A quasi-reticle for an optical device, generated by enhanced multiple reflections.
The reticle comprises fixation target generative means operative to generate a line of ghost images or other multiple fixation targets spaced along the optical axis of the optical device, whereby to enable the viewer by aligning his line of sight with the line of multiple fixation targets to position his eye properly with respect to the optical axis of the optical device. Arndt, Joseph H. Portland, OR. Click for automatic bibliography generation.
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Structured data. Captions English Add a one-line explanation of what this file represents. Military Standardization Handbook. Note : This only applies to original works of the Federal Government and not to the work of any individual U. This template also does not apply to postage stamp designs published by the United States Postal Service since Copyright Office Practices.
July Rework, modificatie en repair van elektronische assemblages Dutch language. March Provee requisitos para materiales de soldadura y procesos para ensambles Spanish language. Stencil and Misprinted Board Cleaning Handbook. IPC Am2.
Handbook of optoelectronics pdf
Guide to Solder Paste Assessment. Acceptability of Printed Boards. Generic Standard on Printed Board Design.
Process Guideline for 3D Printed Electronics. Guidelines for Microsection Evaluation. Press-fit Standard for Automotive Requirements and other high-reliability applications. Generic Requirements for Electronic Product Documentation. IPCB Am 3. Guidelines for Printed Board Component Mounting.