| 摘要 |
Hand held infrared measurement devices are disclosed, having at least two separated laser sighting emitters ( 2 ), which together mark and define a sighting area on a target surface ( 7,7',7 ''). In an embodiment of the invention, separate lasers ( 2 ) are provided which each produce a beam ( 6 ) used to illuminate a respective separate optical beam directing element ( 4 ), mounted between each laser emitter and the target surface ( 7,7',7 ''). The element may be, for example, any of the optical glass fibers, a prism, or a lens, such as a diffraction beam splitter lens, or a refractive lens, each element directing laser light onto the target surface to produce a visually perceptible target marking. The element is preferably made of optical material such as glass or plastic (e.g., methyl methacrylate). Separate laser emitters permit greater brightness displayed on the target within safe operation limits than use of a single laser alone, even with a beam splitter. The laser emitters may each be separately powered and may also each be switched on or off or changed in brightness.
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