Contrast is the distinction between light and dark images and is defined as the ratio of the luminance of the brightest white and the darkest black. Typically 16 to 1 is adequate performance outdoor but more is better. Beyond making a display sunlight viewable, is delivering a complete solution that solves the customers overall needs. The customer is after all, designing and producing a complete system to do a specific task well. There are elements of a system that belong with the display module because of the system design, manufacturing needs, and the effects of the various display elements on the overall performance of the display system.
Backlight methodologies fall into two categories, indirect and direct.
Indirect backlighting is the standard method for lighting laptop LCD as they are manufactured by NEC, Sharp, Toshiba, etc. LCD s have bulbs mounted directly behind the LCD glass and allow many more bulbs to be used allowing maximum light output. Modifying the original backlight system has its challenges not least of which is almost all LCD s are not mechanically easy to modify. More subtle issues also need attention such as creative mounting methods since light output can easily be effected , use of clean rooms for optimum quality, and custom bulb designs for maximum performance and life. Index Matching Films Increasing the darkness of the black with index matching films is another method of increasing the contrast ratio of a sunlight viewable display.