rear sides and disperse the led light to the left and right sides led compared with ccfl employed as a light source can improve the problem of high power consumption warm up and the limits of lifetime furthermore the light through the lens extends the range of the left and right sides on a scanned material therefore the amount of the leds decreases than that skilled in the art used a large number of leds for obtaining a smoother field of light and achieve low power consumption application_number US 40649603 A description some sample embodiments of the invention will now be described in greater detail nevertheless it should be recognized that the present invention can be practiced in a wide range of other embodiments besides those explicitly described and the scope of the present invention is expressly not limited expect as specified in the accompanying claims then the components of the different elements of the scanning light source are not shown to scale some dimensions are exaggerated so that the related components and meaningless portions are drawn to provide a more clear description and comprehension of the present invention first a direction of left and right sides of led is along a direction of a line of leds and a direction of front and rear sides thereof is perpendicular to a direction of a line of leds referring to fig3 a and fig3 b one preferred embodiment of this invention employs a.