| 摘要 |
A hand-held ophthalmoscope modified by the removal or augmentation of the focusing wheel and the addition of a manual or automatic focusing lens system. An electronic imager (CCD array or video camera) is placed optically conjugate to a viewing screen such that focus operations performed by the examiner to adjust the image seen by the examiner on the screen also focuses the image on the electronic imager. This is accomplished by an optical system which includes a straight path from the viewing screen to the patient's eye with a beam splitter interposed to cause the image of the patient's eye to be reflected onto the imager. As a result, when the examiner uses the focusing lens system, manual or automatic, positioned between the beam splitter and the patient's eye, to affect the image viewed by the examiner, the focus of the imager is simultaneously affected as well. Alternatively, the image from the imager is sent to a liquid crystal display (LCD) in the instrument's eye piece; when the examiner focuses the image on the LCD, the image on the imager is focused simultaneously. Also provided is an automatic focusing system for the imager that operates independently of the examiner's focusing adjustments. An automatic focusing system for the imager can also be incorporated in the other two embodiments. The output from the electronic imager can be in digital or analog form and can consist of a single frame or a video stream.
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