Optical Microscopy
| Leica DVM6 Digital Microscope [SOP] |
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| Objectives (diagonal FOV, in mm): |
| - PlanAPO FOV 43.75 |
| - Max. magnification: 190x |
| - Max. resolution: 415 lp/mm (2.4 μm) |
| - Working distance (WD): 60 mm |
| - PlanAPO FOV 12.55 |
| - Max. magnification: 675x |
| - Max. resolution: 1073 lp/mm (0.93 μm) |
| - WD: 33 mm |
| - PlanAPO FOV 3.60 |
| - Max. magnification: 2350x |
| - Max. resolution: 2366 lp/mm (0.42 μm) |
| - WD: 5 mm |
| Lens tilt range: ±60° |
| Stage XY range: 70 mm x 50 mm |
| Stage rotation range: ±180° |
| Stage max load: 2 kg |
| Illumination sources: 4-quadrant ring light, coaxial light |
| Capabilities: XY Image stitching, Z-stack stitching |
| AmScope Optical Stereomicroscope [SOP] |
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| Camera: DCM300 |
| Leica DMi8-M Inverted Microscope [SOP] |
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| Camera: Leica DMC2900 |
Optical microscopy involves the use of visible light and a series of lenses to image samples at high magnifications and resolutions. Optical microscope can vary in functionality, design, and objectives used.
Principle
Optical microscopy uses the interaction between visible light and the surface of the sample to create an image. A series of lenses can allow for the imaging of surface details normally invisible to the human eye.
Limitations
Optical microscopes are often limited by light itself. Since optical microscopes observe visual light which has wavelengths from approximately 380 to 780 nanometers, a variety of limitations arrise.
Resolution
The resolution of optical microscopes is limited by the diffraction limit of light, preventing them from imaging beyond a certain scale. In order to image at a lower scale, scanning electron microscopy must be used.
Depth of Field
Optical microscopes have limited depth of field due to the lenses used. This necessitates re-focusing on different heights of samples at higher magnifications. However, this limited depth of field can be used as an advantage, as described in Focus/Z Stacking. On the Leica DVM6, different objectives with different FOVs can be used to migate this issue, however there will still be issues depth of field issues at high magnifications.
Advantages and Useful Properties
Although there are limitations while using optical microscopy, some properties of light can be taken advantage of.
Focus/Z Stacking
Using the Leica DVM6 and it's software Leica LAS X, images of a sample can be taken at different focus heights in order to create a 3D reconstruction of the sample's surface. This 3D reconstruction can be used to measure different depths of surface features or distances between different locations on the surface. Additionally, this reconstruction can be exported as a 3D mesh for use outside the software.