Sparse Orthogonal Matrices for Scanning Liquid Crystal Displays

Abstract

Abstract-A multi-line addressing technique that is based on sparse orthogonal matrices is proposed to drive the liquid crystal displays (LCDs). Hardware in the column drivers is utilized fully and yet the hardware complexity of the controller is reduced by using sparse matrices to scan the passive matrix LCDs.

Gray Scales by Cross Pairing of Select and Data Voltages in Multi-Line Addressed Liquid Crystal Displays

“…3. The RMS voltage across pixels will be one of four gray scales (G1 to G4) and the expressions of RMS voltages are shown in a compact form using in (5). The four RMS voltages can be obtained by assigning a sign to the second and third terms of the expression in (5)…”

“…Similarly, the expression for is obtained by assigning negative sign to the second and third terms in (5). The selection ratio obtained with these two RMS voltages is the maximum that can be achieved with any addressing technique.…”

“…Gray scales of pixels are also shown. RMS voltage across pixels in first row will correspond to one of the four gray scales (G1-G4) given in (5) and the RMS voltage across the pixels in the second row will correspond to one of the gray scales G5-G7 with the expression given in (7).…”

“…The RMS voltage across pixels is governed by the expression in (5). Data voltages generated from C1 and C2 are paired with select pulses of and , respectively.…”

“…Multi-line addressing techniques use waveforms derived from a set of orthogonal functions or an orthogonal matrix to select rows and to compute the data voltages [5], [6]. For example, Hadamard matrix of order 2 may be used to select two rows at time in matrix LCD (1) Let and be two scalars; then a set of four data vectors i.e., C1-C4 that are formed with these scalars shown in Table I …”