Compensating light source capable of compensating for a light intensity attenuation caused by the optical path and designing method

A designing method for a compensating light source, capable of compensating for light intensity attenuation caused by an optical path, the method comprising:

• selecting a plurality of cold cathode fluorescent lamps, which have a uniform luminance, for use to respectively illuminate a chart with a uniform gray scale and produce a plurality of scanning light beams with respect to the cold cathode fluorescent lamps, wherein the cold cathode fluorescent lamps have different tube diameters;
• using a lens to collect the scanning light beams and focusing them to form an image on a charge coupled device, which has a plurality of image pixels, and the image pixels produce a plurality of sensing voltages with respect to the cold cathode fluorescent lamps, and the tube diameters of the cold cathode fluorescent lamps are related to the sensing voltages with respect to the predetermined light sources, so as to build up relative data;
• using the relative data and the sensing voltages with respect to one of the cold cathode fluorescent lamps, so as to design the compensating light source;
• and
• using the compensating light source to illuminate the chart with the uniform gray scale, so as to detect and check whether or not the compensating light source satisfies the specification, and if it does not then a plurality of other sensing voltages with respect to the compensating light source are produced by the image pixels and another compensating light source is designed.

A designing method for a compensating light source, capable of compensating for light intensity attenuation caused by an optical path, the method comprising:

• selecting a plurality of cold cathode fluorescent lamps, which have a uniform luminance, for use to respectively illuminate a chart with a uniform gray scale and produce a plurality of scanning light beams with respect to the cold cathode fluorescent lamps, wherein the cold cathode fluorescent lamps respectively have different tube diameters;
• using a lens to collect the scanning light beams and focusing them to form an image on a charge coupled device, which has a plurality of image pixels, and the image pixels produce a plurality of sensing voltages with respect to the cold cathode fluorescent lamps, and the tube diameters of the cold cathode fluorescent lamps are related to the sensing voltages of the predetermined light sources, so as to build up relative data;
• and
• using the relative data and the corresponding sensing voltages with respect to one of the cold cathode fluorescent lamps, so as to design the compensating light source, wherein the compensating light source comprises a first light emitting portion and a second light emitting portion, wherein the second light emitting portion is located at two ends of the first light emitting portion, wherein the tube diameter of the second light emitting portion is smaller than the tube diameter of the first light emitting portion, also and the luminance of the second light emitting portion is greater than a luminance of the first light emitting portion.