The Richardson Test Slide Generation III
Back in January 2005, we ordered the above Richardson Test Slide (80302 without cover glass) from Electron Microscopy Sciences for evaluation as we had received numerous requests that we show images taken with this slide.
Based on the technical specifications for this slide, it seemed to be an ideal accepted slide to prove the high resolution capabilities of our microscopes.
Details: Specifications, Outer Pattern, Inner Pattern (PDF Files, use the zoom function to see more clearly)
Note: The actual slide was found to be slightly different to the PDF version and the manufacturing quality was not up to the standard suggested by the PDF version.
We actually started testing the slide in late February 2005 and we discovered the following problems in the sample we received.
When viewing the high resolution pattern with resolutions better than 200nm, it was discovered that either the numbers are in focus or the structures, not both. Even when adding depth of field to the images, it was not possible to see both on the same plane of focus. This suggests that the slide we received was not produced as perfectly as is necessary in order to demonstrate resolution better than 200nm. The surface of the slide is simply not flat enough, unlike another the other test slide we obtained from the German PTB organisation that allows us to demonstrate 100nm, easily.
We have taken a large number of images, using transmitted and reflected light which demonstrate the problem. There are many aspects of the slide we see positively and it would be useful to us if it were not for the uneven layers of the high resolution pattern. Even the ruler is not all on the same level and it is necesssary to refocus when moving across the length of it.
Due to these problems, we returned the slide with a full report hoping we had simply received a poor sample and they could supply us with a better one.
Unfortunately, Richardson Technologies closed down shortly afterwards and we never received another sample for testing.
Despite the sub-standard slide, we have now decided to release some of the better images we obtained from the slide for those who specifically wish to see them. Please take the above into account when you look at the following images.
Although these images do show that the microscope has a very high resolution, the quality of the slide used was of insufficient quality to show 100nm resolution clearly as possible with the German test slide.
All above images copyright 2005: Ortikon and Grayfield Optical Inc.