Abstract: A display device includes L number of display panels where L is a positive integer greater than 1; a driving circuit having L number of controllers for driving the respective display panels; and a central control unit configured to control the driving circuit. The controllers are configured to be synchronized with one another based on a clock signal from the central control unit, and each of the controllers is configured to sequentially and continuously select each one of K number of lines (where K is a positive integer greater than 1) arranged in a row in the corresponding display panel, and allow the selected line to emit light. Further, a direction for sequentially and continuously selecting each one of the lines is set to be the same in all the display panels.

Abstract: A length measuring apparatus is provided that combines upper data with lower data and then outputs the composite data. The apparatus monitors taking down or up a digit of upper data or lower data and synchronization of lower data, thus preventing an occurrence of reading error. When an A/D area showing an area of lower data matches with an upper area quadrant showing an area of upper data (R2, R3), the upper count value outputting the upper data is output without any change. When the quadrant (0, 1, 2, 3) of the A/D area does not match with the quadrant (0, 1, 2, 3) of upper area because of an erroneous timing of a digit-taking-up of upper data (R1, R4), +1 or −1 is added to the upper count value. Thus, the continuity of a measured value can be obtained when the scale is being moved.

Abstract: A measurement signal generating circuit for a linear scale capable of increasing an Signal-to-Noise (S/N) ratio, wherein S stands for Corona signal strength, and N for noise strength ratio of a signal for measurement of a linear scale. A photo detector or a low-pass filter for removing noise entering the measurement signal generating circuit is arranged rearwardly of each of an A phase signal generating circuit and a B phase signal generating circuit. Such construction permits a noise component at a different phase as well as that at the same phase to be effectively removed during synthesis of the measurement signal, to thereby reduce an error in measuring by the linear scale.

Abstract: A length measuring apparatus is provided that combines upper data with lower data and then outputs the composite data. The apparatus monitors taking down or up a digit of upper data or lower data and synchronization of lower data, thus preventing an occurrence of reading error. When an A/D area showing an area of lower data matches with an upper area quadrant showing an area of upper data (R2, R3), the upper count value outputting the upper data is output without any change. When the quadrant (0, 1, 2, 3) of the A/D area does not match with the quadrant (0, 1, 2, 3) of upper area because of an erroneous timing of a digit-taking-up of upper data (R1, R4), +1 or −1 is added to the upper count value. Thus, the continuity of a measured value can be obtained when the scale is being moved.

Abstract: A measurement signal generating circuit for a linear scale capable of increasing an S/N ratio of a signal for measurement of a linear scale. A photo detector or a low-pass filter for removing noise entering the measurement signal generating circuit is arranged rearwardly of each of an A phase signal generating circuit and a B phase signal generating circuit. Such construction permits a noise component at a different phase as well as that at the same phase to be effectively removed during synthesis of the measurement signal, to thereby reduce an error in measuring by the linear scale.

Abstract: In a linear scale, a reference point signal is outputted as a signal which is synchronized with an absolute value. 8 is a a/b phase signal generator forming a two-phase a/b signal of a moving signal by an absolute value which divided the inside of pitch when the a scale moves, 31 is a period counter, 32 is a subtracter, 33 is an up-down counter.