Circular saw that uses a prism to reflect the cut images

A circular saw for sawing a workpiece, said circular saw comprising:

• a housing;
• a sawing assembly comprising a motor, a saw blade and a saw blade shield, said motor being located on one side of said housing, said saw blade being located on an opposite side of said housing and connected to said motor so that said saw blade is drivable by said motor to saw said workpiece, said saw blade shield being secured to said housing and covering a part of said saw blade;
• and
• a prism assembly located in front of said saw blade, said prism assembly comprising a protective cover, a transparent protective plate, a scraper for scraping off impurities attach to a surface of the transparent protective plate, and at least one prism, said protective cover being affixed to a front end of said saw blade shield, said protective cover comprising a window located on a top surface thereof and an opening located on a bottom surface thereof, said at least one prism being located in said protective cover, each said prism comprising an incident surface, a reflective surface located in front of said incident surface, and an exit surface located above said reflective surface, said incident surface receiving an image of said saw blade sawing said workpiece through said opening of said protective cover, said reflective surface reflecting the image received by said incident surface to said exit surface, said exit surface emitting the image reflected from said reflective surface through said window of said protective cover;
• wherein the image shows a point at which the said saw blade cuts a workpiece, and said reflective surface of said prism is located in front of said point.