A DRIVING METHOD FOR A FLAT PANEL DISPLAY APPARATUS AND THE FLAT PANEL DISPLAY APPARATUS

Abstract: A driving method for a flat panel display apparatus and a flat panel display apparatus for executing the driving method therefor, in which the order of display data allotted to one driving integrated circuit is changed at every half the number so as to supply the display data to the driving integrated circuit, whereby output terminals of each film carrier are arranged approximately perpendicular to the side on which input terminals of the driving integrated circuit are arranged. Accordingly, the film carrier is reducible in width in comparison with the conventional one, thereby en­ abling the entire apparatus to be small-sized, resulting in that a display panel of smaller pitch between the picture elements can be driven by the apparatus of the invention.

Description: The present invention relates to a driving method for a flat panel display apparatus and the flat panel display apparatus for executing the driving method. It is desired for mounting technique in the flat panel display apparatus to realize the high density mounting in order to expect simplification of the entire apparatus. Especially, high densification is required for mounting a driving IC (integrated circuit) for driving the display panel. Fig. 1 is a typical view of mounting method of a driving IC disclosed in, for example, Page 70 of "National Technical Report" (Feb. 1987), for satisfying the above requirement. This example forms an electrode pattern on a base film of polyimide resin and thermocompression-bonds a driving IC chip on the base film, thereby expecting an improvement in mounting density. Referring to Fig. 1, reference numeral 1 designates a film carrier on which an electrode pattern is formed by plating Au on the surface layer of Ni. Fig. 2 is an enlarged view of the film carrier 1, at the center of which a driving IC chip 2 comprising a shift register and a level shifter is mounted, the driving IC chip 2 being rectangular when viewed in plane. Fig. 3 is a typical view showing an arrangement of input and output terminals at the driving IC chip 2. Input signal terminals are arranged on one side of the rectangular chip 2, output signal terminals being arranged on other three sides clockwise (or counterclockwise) in regular order. The output signal lines from the output signal terminals at two parallel sides of the chip 2 show on the film carrier 1 a traveling pattern such that the output signal lines at first travel outwardly from the driving IC chip 2 and then perpendicularly bend and travel toward an electrode of a liquid crystal display panel 3. The above-mentioned example using the film carrier 1 in order to mount the driving IC chip 2 improves the mounting density more than the IC packaged in the conventional way. Next, explanation will be given on operation of the aforesaid conventional example. The driving IC chip 2 is given display data sequentially through the input signal lines and outputs driving signals to the liquid crystal display panel 3 through the output signal lines. Concretely, the number of data, that is, the number of outputs, allotted to one driving IC chip 2 is represented by 2N, and the display data to be supplied to electrodes L(1), L(2) ... L(2N) on the liquid crystal display panel 3 connected with the output signal lines of driving IC chip 2 are represented by D(1), D(2) ... D(2N), the display data are supplied in the order of D(1), D(2) ... D(2N) to the driving IC chip 2, D(1) being outputted from an output terminal OUT(1), D(2) from that OUT(2), and D(2N) from that OUT(2N). Pitch between the picture elements on the liquid crystal display panel 3 becomes narrow following an improvement in resolution of the flat panel display apparatus, then the relation between a width w of the film carrier 1 and a product p × m of the pitch p between the picture elements multiplied by the number m of data allotted to one driving IC chip 2 becomes problematically. In case of the aforesaid conventional flat panel display apparatus width w₁ of the film carrier 1 is limited by the sum of a width a of the driving IC chip 2 and pattern printing width b and c. On the other hand, a width w₂ of film carrier 1 permitted for practical use depends on the product p × m. As shown in Fig. 4, there is no problem when a relation of w₂ ≧ w ₁ (p×m ≧ a+b+c) is maintained, but when the pitch p between the picture elements decreases following the improvement in resolution of the liquid crystal display panel 3 to cause a relation of w₂ < w₁ (p×m < a+b+c) as shown in Fig. 5, geometrical inconvenience, that is, the troublesome problem about mounting between the adjacent film carriers 1 is caused. It is an object of the present invention to provide a flat panel display apparatus in which the width of the film carrier is less dependent from the number of output terminals so that a high mounting density is possible even in case of a great number of output terminals of the integrated circuit. This object is solved, according to the invention, with the features of claim 1. The flat panel display apparatus of the invention has a reduced width of the film carrier in comparison with conventional apparatuses, whereby the entire apparatus is simplified. A display panel using flat panel display apparatuses of the invention can be driven, even when the pitch between the picture elements is very small. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a typical view showing the mounting method of the conventional driving IC, Fig. 2 is an enlarged view of the conventional film carrier, Fig. 3 is a typical view showing arrangement of input terminals and output terminals of the conventional driving IC chip, Figs. 4 and 5 are typical views showing the relation between a width of an actual film carrier and that of a film carrier permitted for practical use, Fig. 6 is a typical view showing the mounting method of a driving IC for executing the driving method of the invention, Fig. 7 is an enlarged view of a film carrier for executing the driving method of the invention, and Fig. 8 is a typical view showing a printing pattern on a liquid crystal display panel for executing the driving method of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, concrete explanation will be given on an embodiment of a flat panel display apparatus of the invention. Referring to Figs. 6, 7 and 8, reference numeral 1 designates a film carrier which uses polyimide resin as a base film, 2 designates a driving IC ship being rectangular when viewed in plane, and 3 designates a liquid crystal panel. One of two glass substrates constituting the liquid crystal panel is shown in Fig. 6, the other being shown in Fig. 8. In addition, in the embodiment, in the same way as the conventional example, the number of data, that is, the number of outputs, allotted to one driving IC chip 2 is represented by 2N and display data to be supplied to electrodes L(1), L(2) ... L(2N) at the liquid crystal panel 3 connected to the output terminals of the driving IC chip 2 are represented by D(1), D(2) ... D(2N) respectively. In the same way as the conventional example (refer to Fig. 3), the input signal terminals are arranged on one side of the driving IC chip 2 and the output signal terminals are arranged clockwise (or counterclockwise) in regular order on other three sides. The output terminals of the film carrier 1 are arranged on the sides perpendicular to the side where the input signal terminals of the driving IC chip 2 are arranged. The output terminals of the film carrier 1 and the driving IC chip 2 are connected with each other by the printed pattern shown in Fig. 7. In other words, the output signal lines from the two parallel sides of driving IC chip 2 travel horizontally to connect with the output terminals of film carrier 1 and the output signal lines from the remaining side of driving IC chip travel downward and then bend perpendicularly to connect with the output terminals of the film carrier 1. The printed pattern on the glass substrate of the liquid crystal panel 3, as shown in Fig. 8, travels from the output terminals of film carrier 1 toward the center of film carrier 1 and then perpendicularly bend to travel toward the display unit of liquid crystal display panel 3. Such printed pattern connects the output terminal OUT(1) of driving IC chip 2 with an electrode L(N+1) on the liquid crystal display panel 3, that OUT(2) with an electrode L(N+2), ..., that OUT(N) with an electrode L(2N), that OUT(N+1) with an electrode L(1), that OUT(N+2) with an electrode L(2), ..., and that OUT(2N) with an electrode L(N). Next, explanation will be given on operation of the flat panel display apparatus of the invention. The display data is supplied to the driving IC chip 2 in the order which is established by dividing the display data allotted to one driving IC into halves and exchanging the former half and the latter half. In other words, the display data is supplied to the driving IC chip 2 in the order of D(N+1), D(N+2) ... D(2N), D(1), D(2) ... D(N). Accordingly, the display data D(N+1) is outputted from the output terminal OUT(1) of driving IC chip 2, that D(N+2) from OUT(2), ..., that D(2N) from Out(N), that D(1) from OUT(N+1), that D(2) from OUT(N+2), ... and that D(N) from OUT(2N). At this time, since the output terminals at the driving IC chip 2 and electrodes of the liquid crystal display panel 3 are connected with each other through the aforesaid printed pattern, the display data D(1) is accurately outputted to the electrode L(1) at the liquid crystal panel 3, that D(2) to the electrode L(2), ..., and that D(2N) to the electrode L(2N). Next, explanation will be given on comparison of width of the film carrier of the invention with that of the conventional film carrier. The width of the conventional example, as shown in Fig. 2, is limited by a width a of the driving IC chip 2 and printing widths b and c of the printing pattern. On the other other hand, the width of film carrier of the invention, as shown in Fig. 7, is limited mainly only by a width a of the driving IC chip 2. In other words, since the printing width of the printing pattern of the invention is negligible, the width of film carrier is reducible more than the film carrier of the conventional example. Accordingly, in the present invention, even when the pitch p between the picture elements becomes smaller, a geometrical problem is not caused as far as a product p × m of the pitch p between the picture elements multiplied by the number m of data allotted to one driving IC chip 2 is larger than the width a of the driving IC chip 2. As a result, there is no geometrical problem even when the pitch between the picture elements is reduced in order to obtain high resolution. In addition, the present embodiment uses the liquid crystal display panel as the display panel, but other display panel, such as EL display panel, may of course be usable for the present invention. As this invention may be embodied in several forms, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the meets and bounds of the claims, or equivalence of such meets and bounds thereof are therefore intended to be embraced by the claims.

Claims: A flat panel display apparatus with driving integrated circuits (2), each of which is rectangular in plan view and has display data input terminals on one side and driver output terminals on the other three sides, and film carriers (1) on which each of said driving integrated circuits (2) is mounted and on which input signal lines connected to input terminals of each of said driving integrated circuits and output signal lines arranged to provide sequential data connected to output terminals of each of said driving integrated circuits (2) are patterned; characterized in that all the output terminals of each of said film carriers (1) are arranged on the sides approximately perpendicular to the side on which said input terminals of each of said driving integrated circuits are arranged and in that said input signal lines are arranged to allocate to each of said driving integrated circuits sequential display data divided into halves which are interchanged. The flat panel display apparatus according to claim 1, wherein said output terminals of each of said driving integrated circuits (2) are arranged clockwise in regular order. The flat panel display apparatus according to claim 1, wherein said output terminals of each of said driving integrated circuits (2) are arranged counterclockwise in regular order. The flat panel display apparatus according to one of claims 1-3, wherein each of said film carriers (1) has polyimide resin as a base material.

Inventors: YOSHIOKA, KAZUO
Applicants: MITSUBISHI DENKI KABUSHIKI KAISHA
Application year: 1988
Main classification: G02F1
IPC codes: G09G3, G02F1, G09F9