I am starting to think that the Effective Contrast Ratio (ECR) specified in the Rugged PC Review article is too narrow in scope. Based on the capabilities in either optical films or inherent within the LCD TFT itself, a reflective or transflective display would have a variable, say TRANS_INC_NIT, that would be proportional to the sunlight intensity and would help improve the final ECR value. The current ECR equation uses 10,000 nits for average sunlight.
Perhaps we could use the following modified equation:
ECR = 1 + ( (AMB_NORMAL_NIT + TRANS_INC_NIT) / ( 10,000 NITS * SURFACE_REFLECTIVITY_PERCENTAGE) )
Winmate discusses estimated NIT requirements based upon viewing environments here:
http://www.winmate.com.tw/Sunlight_Readable.htm
The following links, which I have no time to read on my lunch break, provide a deeper discussion of transflective LCD operation and testing, but no visible modified ECR equations:
http://lcd.creol.ucf.edu/publication...ID06_p_157.pdf
http://www.hec.afrl.af.mil/Publicati..._2428Meyer.pdf
http://www.freepatentsonline.com/20050006652.html
http://www.qualcomm.com/technology/i...hite_Paper.pdf
I may contact the author of the Rugged PC Review article and get his take on the impact of transflective operation on the ECR equation.
Skipping lunch to research car PC displays...man, I may need to join a support group.
