By removing out-of-focus light from above and below the focal plane, particularly in specimens > 20 µm thick, the new Olympus Disk Scanning Unit (DSU) uniquely delivers confocal-like images with excellent contrast and resolution compared to conventional wide-field microscopy. To reject the out-of-focus light, the DSU places a spinning disk, with an alternating pattern of vertical and horizontal slits, in the confocal plane of the microscope. Spinning at 3000 rpm, the slit disk creates virtual pinholes which produce a similar effect to the pinholes used in confocal laser scanning microscopy (cLSM).
DSU slit disks feature a unique, patent-pending, design which improves resolution, contrast and Signal/Noise ratio in conventional wide-field fluorescence microscopy to provide the semi-confocal optical sectioning. Furthermore, by using arc lamp excitation sources, the Olympus DSU offers the maximum wavelength flexibility within an economical package. The DSU disk and optical components are all UV compatible and deliver outstanding performance from 350 - 700nm, making it suitable for most available fluorochromes.
The crisp, confocal-like, images with controllable depth of field produced by the DSU can also be collected as a series of optical sections (Z-stack) from specimens. Images are acquired using a CCD camera, rather than the photomultiplier tubes used for cLSM, meaning that no sophisticated processing is required. By offering full-frame CCD image capture at up to 15 frames/second, the DSU is an excellent tool for live-cell applications where speed of acquisition and minimal phototoxicity is paramount.
Disk operation is fully motorised, allowing a computer to switch remotely between wide-field and DSU modes. The system can be equipped with a motorised filter-wheel to maintain colour temperature in different observation modes and includes a motorised filter turret for the convenient switching of fluorescence filter in DSU mode. In addition, the DSU is highly flexible and can be combined with motorised microscopes such as the upright Olympus BX61 and the inverted Olympus IX81 for 3D semi-confocal imaging.
By integrating the DSU into the versatile Olympus imaging systems - cell^M and the real time -cell^R, the DSU is an ideal device for optical sectioning in combination with a variety of dedicated imaging applications.