XV. Multi-Viewing attachments
A multi-viewing attachment is one of the most useful accessories that you can get for a microscope. It can also be one of the most frustrating. A multi-viewing attachment allows from two to more than eighteen people to see the same image. Most makers design there systems to be at their best when used by two to six viewers. A.O. has been the driving force in multi-viewing. The first multi-viewing attachment was the dual head accessory. This allowed two people to sit at the same microscope facing each other. A splitter prism divided the light in half and sent each head 50% of the light. This worked well but it was very difficult for the users. They were both draped over the microscope playing kneesies with each other.
Later on the face to face system was improved by other manufacturers. They used a mini-boom to push the second user away. This makes every one happier. A.O. then came out with side by side dual view. This used the same 50%-50% prism but the second head was at the end of a boom arm so the users sat side by side. This is a real advantage for a lot of users. It is much more comfortable and it is easier to find counter space for the microscope.
Now that A.O. knew how to make a boom arm system they could make a multi-view attachment. They used two booms with two 50%-50% prisms at the ends so that two heads could be placed at the end of the booms. These prisms are fed by a prism system that sends 40% of the light to each boom and 20% to the central head. This means that each head gets 20% of the light.
A six headed microscope should have a 12V-100W halogen light source. While modern optics are efficient you are still getting only 20% of the light. If you work at high powers or with dark, thick specimens this becomes imperative. Most manufacturers now make a system like this. As long as it stays a six heads it works quite well. Over the years users wanted more heads for larger conferences and teaching so dealers and sales reps. had the idea to expand this simple six headed system to more and more heads using these modular booms and dual view systems. I have seen system in operation with more than fourteen heads! While they work they do not work well.
Above six heads the light gets unevenly distributed, light gets hard to find and users may not all be seeing the same thing. Before I would buy a microscope with more than six heads I would want to see it demonstrated for at least a day. I would use it for all the tasks I wanted it for and I would look at several vendors.
Do I sound a little down on big multi-headers? Well it is from experience. They can be very difficult instruments. Now a six headed microscope is not all that hard to maintain. Its just big but it is still in its design parameters not pushed far outside them.
If teaching is part of what you do you need to look at a dual or multi-view module. They make teaching far easier and directly interactive. Since all manufacturers include a pointer system on their systems you can easily point to the important features of the specimen.
Most manufacturers have a lighted pointer controlled by a joy stick on the multi-view module. While this is a great convenience it is also a problem. The problem is that most manufacturers use a separate power supply for the pointer bulb. Its real easy to forget to turn of the pointer and burn out the bulb.
Some third party makers are using fiber optic cables to get light from the microscope bulb and bring it to the pointer. This works quite well and I wouldn't be surprised to see manufacturers start to build this into pointers.
What this means to you
Multi-view heads can make teaching a lot easier. Up to six heads they are real easy to set up and use. Above six heads they can be a problem.