Microscopes/Projectors/Illumination units & Others

Microscopes/Projectors/Illumination units & Others

About auto-focus microscope (AF microscope)

When it comes to auto-focus, generally, you may think of what is used in digital cameras.

Digital cameras, etc. come into focus even when a person hold a camera moves to some extent, or the object somewhat moves back and forth.

This does not mean that digital camera’s auto-focus is tracking completely. The fact is that it has a long depth of field. Therefore you do not need to worry that it may go out of focus, even if auto-focus does not focus on the object in strict terms.

However, that is not the case with microscopes.
When the magnification of an object lens of a microscope is as high as x100 (the overall power exceeds x1000. ), the focal depth (focusing range) is approximately 0.3μm (0.0003㎜).
This means if the position of the microscope and the sample is misaligned just 0.3μm, it will be out of focus.

Our auto-focus is a unit product in which high technology is concentrated: it performs this ultramicroscopic focusing automatically, and, at the same time, even when the sample moves, it is kept in focus, being tracked.

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  • The only auto-focus system for the microscope in the world that utilizes CCD licensor.
  • It goes without saying with metal surfaces that have high reflectance, it can deal with paper, filter, etc. that have low reflectance. It also shows remarkable performance with glass or transparent plastic, which cannot be obtained in other systems.
    It is a high performance auto-focus system with few samples it is not good at.
  • It tracks rolling or tilting of a sample at ultrahigh-speed, with trackability that is at the highest level in the world.
    A newly-developed model, in which two licensor system is adopted, can track a glass substrate that is on an ultrahigh-speed stage moving at the speed of 2m/sec, and keep the object in focus.
    ※Conditions within the object lens x20, vertical displacement ±150μm (actual record of being mounted on inspection devices for major LCD manufacturers)
  • It supports broad range of magnification from macro to micro
    It can handle an object lens with magnification from x0.5 to x150.
Description of auto-focus system
Our auto-focus microscopes are mainly composed of a licensor section, AF pattern section, driving section, controller section, and lens tube section. A striped AF pattern is placed at the position of a field diaphragm of the reflected illumination section, and a stripe pattern is projected on the work. The stripe pattern projected on the work is split to two optical paths at the optical path difference prism, the contrast of the stripe is detected at two different places of the licensor, the AF controller performs high-speed computing, and the driving section is moved to a position where both signals approximate in order to put it in focus. The newly developed two-licensor system is a system that uses, as the name signifies, two licensors, doubling the detection speed of stripe contrast, and accelerates the response speed.
Item Licensor system Laser system Video signal system
Tracking type auto-focus capability ×
Support for transparent body [plain glass] samples ◎[◎] ○[△] ×[×]
Support for samples with low reflectance × ×
Support for samples with holes or a dents ×
Focusing speed within 1 second
(Reduced more with various condition settings)

The licensor system adopted in our auto-focus microscopes is very capable compared with other systems.

Auto-focus introduction video

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