Scanner using a solid state illumination source

An illumination source 14 including red LEDs (Fig2, 101, not shown) green LEDs (102), and blue LEDs (103) provides illumination for a scanner 2. The LEDs are arranged in an array to generate spectrally and spatially substantially uniform illumination on the surface of an object, such as printed media, which is to be scanned. The arrangement of LEDs includes a plurality of groups of three LEDs (100). Each group of LEDs (100) includes a red LED (101), a green LED (102), and a blue LED (103). The LEDs of like colors are connected in series. Power is supplied to the three groups of series connected LEDs by three current sources (Fig3 not shown 200, 201, 202). The three current sources (200, 201, 202) are each configured to supply a constant current to one of the groups of series connected LEDs. Each current source (200, 201, 202) supplies a magnitude of current so that the resulting light provides substantially uniform illumination on the printed media. A further embodiment of the illumination source 14 includes LEDs (Fig4 not shown 300) that can each generate light having a substantially uniform energy spectrum over the range of visible light frequencies. A third embodiment of the illumination source 14 includes a plurality of groups of four LEDs (Fig5 not shown 400). Each of the groups of LEDs (400) includes a red LED (401), a green LED (402), a blue LED (403), and a yellow LED (404).