JPS60205496A - Liquid crystal driving - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] b) Industrial application field Regret The present invention relates to a liquid crystal driving method for displaying halftones.

(2) Prior Art In general, when driving a liquid crystal display, the magnitude of applied voltage and display density do not correspond linearly. Therefore, JP-A-58-1
It has been proposed, as in Japanese Patent No. 25587, to display by dividing all pixels. That is, as shown in Fig. 1, tcl pixels (
1) is divided into a plurality of divided micro regions t2J.
t2J... so that the selected points are approximately uniform within the pixel 111, and the pixel density is displayed at that lighting density. In this method, the display is either lit up or not lit up in the minute areas (2) (2)... within the pixel, so it is not affected by variations in applied voltage or temperature changes, but depending on the size of the pixel (1). On the other hand, if the divided minute areas [2) [2]... are not made sufficiently small, the display will appear mottled, requiring fine processing, and from the point of view of the driving means, it is not necessary to drive the number of pixels (1). Area +21
[2) Since drives corresponding to the total number of... are required, there are many disadvantages such as difficulty in wiring and an increase in the number of drivers.

C) Purpose of the Invention The present invention has been made in order to correct the above-mentioned disadvantages, and its purpose is to provide a liquid crystal driving method that can perform good halftone display.

2) Structure of the Invention The present invention Vii period is divided into a plurality of periods, and the display density 2 is indicated by the number of scans within the divided period.Hereinafter, the present invention will be described in detail based on examples.

E) Embodiment FIG. 2 is a schematic diagram illustrating the driving method of the embodiment of the present invention.
FIG. 6 shows a timing chart thereof, and FIG. 4 shows a plan view of the resulting display. In the figure, there are four pixels (a) (b) (c) (d) vc t vz and four floors ill? This is an example of how to display it. As shown in Figure 21 and @6, in the example of 5I, one period (f) is repeated six times (tl) (tz) (tz).
It consists of As for pixel (a) VC, a selection signal is applied during the entire scanning time (tx) (tz) (tz) and the lighting state is always maintained, so that the darkest display is performed (in the positive state). For pixel (b), a selection signal is applied only for scanning time (tx) (tz), and 2/2 of one cycle is
Only 3 lights are on. Therefore, the density appears lower than that of the viewer VcF'i pixel (a). Similarly, V at pixel (e)
A selection signal 4i+ is applied only during il/3 periods, and a non-selection signal is applied to pixel (d) during all scanning times.

In such a display, three screens are driven during one cycle, and the density is displayed depending on how many times they are turned on. Therefore, it is sufficient if at least one of the three screens does not appear to flicker when turned on or off. Furthermore, if the number of screens, that is, the number of scans is increased, the number of gradations increases accordingly, but there is a limit because the responsiveness of liquid crystal is poor.

Because of this, the frame frequency of one period (f) is 50
You can set it to 5 so that it falls between Hz and 200Hz, but by adding scanning (scanning with no scanning selection) or applying selection signals in random order, you can improve the gradation expression when displaying the same gradation at the same period. It can be done clearly.

h) Does the present invention apply to liquid crystals as described above? This is a liquid crystal driving method that displays m gradations (where n, mV'i is a natural number) by scanning the same pixel n times in one period with the sandwiched electrodes and applying a selection signal n' times out of the 0 scans. Therefore, since the number of wirings does not increase and a selection signal is used for lighting, halftone display can be performed satisfactorily without being affected by temperature or the like.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram explaining a conventional liquid crystal display method, Fig. 2 is a schematic diagram explaining a driving method according to an embodiment of the present invention, Fig. 3 is a timing diagram of the driving method shown in Fig. 2), Fig. 4 is the second
A top view of the display observed by driving the figure. Applicant: Sanyo Electric Co., Ltd. and one other patent attorney: Shizuo Sano, Figure 3: +;, +-7=

Claims (1)

[Claims] 1) Scanning the same pixel n times within one cycle on a liquid crystal display,
By giving a selection signal n/times among the n times, m
A liquid crystal driving method that uses gradation (where 1%m is a natural number) to display f as a percentage sign. 2) Frame frequency Vi of the above one period 50Hz or more 20
1. The liquid crystal driving method according to claim 1, characterized in that the driving frequency is set to 0 Hz or less.