screen illumination การใช้

Just as well; no matter how low I adjust the screen illumination, it's still an annoying distraction glowing at me.
However, because the lamp was suspended above and outside the reflector, a large amount of light was cast to the sides inside the projector body that was wasted, thus requiring a higher power lamp for sufficient screen illumination.
More modern overhead projectors use an integrated lamp and conical reflector assembly, allowing the lamp to be located deep within the reflector and sending a greater portion of its light towards the Fresnel lens; this permits using a lower power lamp for the same screen illumination.
Rabbi Dr . Raphael Zarum, Dean of the London School of Jewish Studies wrote that the Shabbos App developers : " have found solutions to the halachic challenges of typing-writing, screen illumination, sound generation and battery drainage and charging . . . . I have no doubt that all major halachic authorities will come out against this, except for use in emergency situations.