SHADOW MASK
Shadow mask is one of two major technologies used in CRT-monitors alongside the aperture grille. The shadow mask is positioned inside the CRT tube, just behind the phosphor-coated screen and is a metal sheet with tiny holes or slots arranged in a specific pattern.
When an electron beam is emitted from the cathode, it passes through the shadow mask before reaching the screen. The holes or slots in the shadow mask allow the electron beams to pass through and hit specific areas on the phosphor coating, creating the desired colors and forming the image on the screen.
The main purpose of the shadow mask is to ensure that the electron beams from the cathode strike the correct phosphor dots on the screen. The pattern of the holes or slots in the shadow mask corresponds to the arrangement of the phosphor dots on the screen. This alignment ensures that each electron beam hits the appropriate phosphor dot, resulting in accurate color reproduction and image clarity.
The design and construction of the shadow mask are critical factors in determining the overall image quality of a CRT display. Factors such as hole or slot size, spacing, and material properties influence the precision and efficiency of the electron beam control. A well-designed shadow mask minimizes cross-talk between adjacent color phosphors, reduces color bleeding or smearing, and enhances the sharpness and detail of the displayed image.
