| 摘要 |
<p>In a system producing an electrical output representing the characteristics of a blood smeared slide, an optical system permits an operator to comfortably view the slide while it is being intensely illuminated. A television type detector produces the electrical output representing the optical characteristics of the blood on the slide. This detector requires that a very intense source of light be applied to the slide. In order for the operator to simultaneously view the slide a duplex beam splitter is inserted in the light path. A first prism in the beam splitter diverts a small percentage of the intense light to the operators viewing eye pieces. The first prism is a 30 DEG -60 DEG - 90 DEG prism having an index of refracton such that the reflection from the second surface is directed out of the prims and away from the viewing eye piece to avoid ghost images. A second prism having the same geometry and index of refraction re-establishes proper direction of the light beam between the slide and the detector. The small portion of light directed from the first prism to the viewing eye piece is predominantly polarized in one direction. The degree of polarization is easily calculated by Fresnell's law. A linear polarizer between the first prism and the eye piece is adjustable to provide continuously variable light attenuation. Adjustment of the linear polarizer through 90 DEG rotation is sufficient to achieve the full light attenuation range.</p> |
