Optical Bridge
Definition
The beam-splitter and prism assembly that couples the two microscope bodies of a comparison microscope and produces the split-field composite image in the eyepiece.
- Instrument
- Comparison microscope
- Function
- Merges two optical paths into one split-field view
- Key components
- Beam splitter and prism assembly
- Output
- Single composite eyepiece image
Common questions
Why does a comparison microscope need an optical bridge at all?+
Without it, an examiner would have to look through two separate microscopes and mentally compare two images. The bridge lets the examiner view a bullet or tool mark from one scope alongside a reference sample from the other in a single field, so alignment and striae matching happen side by side in real time.
Can misalignment of the optical bridge affect a comparison result?+
Yes. If the bridge is not properly calibrated, the split-field junction can introduce parallax or magnification mismatch between the two halves, which can distort apparent alignment of striations. Instruments are checked and adjusted as part of routine maintenance for this reason.
Related terms
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