What errors should be avoided in the use of reading microscope
When using the reading microscope, care should be taken to avoid large human errors in reading, which may easily cause visual errors.
1. Parallax: The parallax of optical measuring instruments is due to the fact that the image of the measured object is not on the same plane as the scale for measurement, so when the observer's eyes move, there will be a relative displacement between the image and the scale.
The reading microscope consists of an eyepiece and an objective lens. The marking line is located between the eyepiece and the objective lens. To eliminate parallax, the eyepiece should be adjusted first to make the image of the crosshair clear, and then the lifting knob should be adjusted to make the image of the measured object clear. Move the eye , if there is no relative displacement between the image of the measured object and the image of the crosshair, it means that they are already in the same imaging plane.
2. Pitch error: Since there must be a gap between the internal thread and the external thread of any screw measuring device, the readings corresponding to different rotation directions must be different, and this difference is called pitch error. Therefore, when using a reading microscope for length measurement, the crosshair should be advanced in the same direction, aligned with both ends of the measured object, and not backed up halfway, so as to eliminate the pitch error.
