This part of IEC 63181 specifies measuring methods for LCD multi-screen display terminals. To evaluate the characteristics of LCD multi-screen display terminals, the following measurement items are specified: Gap (physical, optical) -- Detailed splicing precision; Splicing deviation Splicing accuracy of active areas of LCD splicing screen; Installation deviation -- The flatness of terminal surfaces in vertical and horizontal directions; Luminance uniformity Luminance uniformity of adjacent LCD units; Chromatic uniformity Chromatic uniformity of adjacent LCD units.