A Closer Look

Before we get to the performance, let's take a quick look at how Canon have managed to cram so much into such a small box. At just over an inch deep, there was clearly no way to use the mirror and lens arrangement present on most other scanners, so what did they do? The answer is LIDE, Led InDirect Exposure

As you can see, with conventional CCD technology, the scanning head must be large in order to incorporate the array of mirrors and lenses needed to get the document image to the CCD itself. The problem with this arrangement, other than size, is it is dependant on the quality of the mirrors and also the alignement too. Use cheap glass or position a mirror off axis and you end up with gemometric image distortions such as pin cushioning or barrel. There is also a risk of ghosting and internal flare caused by badly controlled reflections. LIDE however takes a new approach to scan head design.

The white light needed to illuminate the documant is actually produced by a row of tightly packed clusters of LED's (Light Emmiting Diodes). The red, green and blue LED's combine to produce a pure white light, which is then fed into a pure crystal/prism array which combines and diffuses the light, leading to a very even source with reduced tendancy for hot-spots. The result is that your document benefits from accurate edge to edge lighting of a remarkably even nature. Also, because the use of mirrors is eliminated, there is little or no possibility of geometric distortion or internal anomolies, leading to brighter, crisper, sharper scans.

The other advantage with LIDE is power consumption. Because LED's require much less power than cold cathode tubes etc. The N 650U's maximum power consumption is an almost unbelievable 2.5watts. This leads to one major advantage this scanner holds over almost all others.......NO AC ADAPTOR.

 

Continued