| 摘要 |
A hand-held lamp instrument has a substantially elongated handle that houses one or more batteries and that connects to a line filament lamp. A front knob is threaded to the handle so that it is rotatable about the elongated axis of the handle. The front knob has an internal hollow section that houses one or more imaging elements to generate a slit image of the line filament out through an aperture in the front knob and away from the instrument. The rotation of the front knob axially displaces the imaging elements relative to the lamp to control the magnification and distance of the slit image. A rear knob also threads to the handle and rotates about the axis to provide an electrical switch. The rotation of the rear knob displaces the rear knob relative to the handle and between a first "ON" position and a second "OFF" position. A retaining ring, e.g., a Smalley ring, is mounted into a groove in the handle and between the handle and a groove in the rear knob, to provide a mechanical and tamper-proof stop between the first and second positions. A window in the front knob provides a visual indication of whether the light filament is on. |
