Stereomicroscopes from Olympus Alleviate Eye Strain

A new range of stereomicroscopes launched by Olympus at the end of 2003 has challenged conventional microscopy wisdom, and should mean happier eyes and fewer headaches for those who spend long hours at a microscope.

Central to the SZ2 range are ComfortView eyepieces with pupil aberration control (PAC) technology, which alters the size of the users’ eye pupils when viewing the image.

On looking into a stereomicroscope, light from the device enters the pupils, forming separate images on the retinas of each eye. These images are then integrated by the brain to form a single picture. A smaller pupil size results in a sharper image being formed on the retina as the light is focussed through a narrower gap - but the eyes have to work hard. Increase the pupil size, however, and the eyes accommodate more easily, meaning the 3D image is easier to find - but the image becomes less sharp.

‘This doesn’t matter though,’ says Gunnar Schroder from Olympus Europa. ‘Beyond a certain pupil focus size there is no practical improvement in image quality.’ Olympus is the first company to include a system of this type in their microscopes.

PAC technology exploits this ‘point of no improvement’ to increase the pupil size when looking at the image, effectively making it less focussed and going against the traditional drive for precision and resolution above all else.

The development came after Olympus customers reported tension headaches and nausea accompanied by difficulty in forming a 3D image after using a microscope for a number of hours. This is because the brain has to work hard to fill in the gaps in the picture as it switches between the 2D and 3D image. ‘Although the eye does not detect any optical difference in the image quality, it feels different,’ says Schroder.

Olympus has also reduced the angle of the microscope eyepieces to 10° from the conventional 12° angle. This has reduced the amount of stray light entering the optical system, which means improved contrast and less flicker. ‘Studies showed that the ten degree conversion angle of the two optical light paths seems to be the optimum,’ says Schroder. ‘It is a natural view with relatively straight eyepieces and many people reported that it was easier to see the 3D effect when the eyepieces were brought closer together, which also contributes to the reduction in eye strain.’

The ComfortView system only applies to the microscope eyepieces, so any digital imaging equipment connected to the unit is attached via a separate camera path that is not affected by the reduction in image quality.

Other developments incorporated into the range include improved coating technology and use of the latest glass materials to produce more natural colours in the sample viewer. An increased range of lighting and new suspension systems have also been added.

The electronics industry is expected to be the largest user of this microscope series. Stereomicroscopes are used for routine inspection of circuit boards in electronic devices of all types. Automotive applications are also a large area for Olympus, with Formula 1 at the cutting edge of research.

‘Ferrari use these microscopes for checking cylinder heads, cracks on car chassis and developing new plastics and compounds, among other things,’ said Schroder.

Other applications include large drug safety tests performed by pharmaceutical companies, botanical applications, and use in schools and universities for teaching basic microscopy techniques.


Posted January 2004


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