JPS58111089A - Electrochromic display element driving circuit - 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] The present invention is directed to a drive circuit for an electrochromic display device.
It is something to do.

Each display segment of an electromagnetic display device has a different resistance value of the Nesa film, and its own resistance value also differs depending on the area of the display segment, so a pulse of a constant voltage and a constant width is applied to each display segment. Then, the amount of charge injected into each of them differs, causing contrast unevenness.

In order to solve this problem, conventional techniques have been to maintain a constant Nesa membrane resistance by inserting an adjustment resistor in series with each display segment, or by changing the shape of the Nesa membrane according to the number or size of the display segment. Such efforts have been made.

However, these methods are extremely complicated to adjust, and the overwriting effect is unavoidable. Moreover, there are various restrictions on the drive circuit, the area of the display segment, and the electrode resistance.
-It was unfavorable in terms of progress and cost.

Since the coloring was based on the dynamic pressure, the coloring density changed depending on the number of display segments to be colored, and it was easy to receive results.

Therefore, in the present invention, coloring is carried out by constant current driving and the colored display segments are electrically connected to each other so that the degree of coloring is kept constant.

Hereinafter, one embodiment of the present invention will be explained based on the drawings.Tuna 1
In the figure, 08 is a vibrator, D butterfly divider 0T is a counter such as a date or -8, and DI is a decoder. P.G.
1 is a pulse generating circuit which generates a coloring pulse after generating a decoloring pulse every time a carry is generated. A is an electrothalomic display device, DPI is a segment drive path, DRI is a common electrode drive path,
B is a constant current circuit, and FIG. 2 shows these components in detail.

In the figure, an electrochromic display device has a display segment 81L made of an electrochromic material.
-8g and the common electrode C are filled with a tortoise shell (not shown). Constant current R (b) path B is the gate circuit Gh
Deltsion mode field effect transistor (hereinafter referred to as F
It's called l. )? 1. IFIC in enhancement mode
It consists of T-IFm, Fl*F4 e resistance, R, analog switch 81, s, and L inverter TI. FIT-IFI, F4 constitute one current mirror path, Fll1T-Fl, y.

A constant current determined by the resistor RE flows through. Is the common electrode drive path DR, one element? -1! '@, F, and an inverter Ts. The oil composition is segment drive--road D.
A part of RI is shown, 83 to 8I are analog switches, t, to p are FICT, ()s to ()ll are gate circuits, and 'rs to'r1s are inverters.

Next, I will explain the operation.

When the contents of the counter CT are incremented, a decoloring pulse Pam is first generated from the terminal PR of the pulse generating circuit PG.

By this pulse, the common electrode 1-- path DRI PET-
F is turned on and the common electrode C is grounded, and
The analog switch 81 of the constant current circuit B is turned on, and the constant current Illffl path B operates. On the other hand, when analog switch S4 is turned on and FIT-F and ~F1m operate, analog switch 81%all is turned on via gates -110s ~G$, and each display segment 8a-8g is electrically connected. be done. Therefore, constant current circuit B (Z) F1m? -IPl to analog switch, S4. Shi! 〒-1 '1ms display sexmen)!
A current flows through common electrodes 3a to 88m and common electrodes C and 11-Fl, and all display segments 8 to sg are once decolored.

When the above decoloring operation is completed, the terminal P of the pulse generation circuit PG
A colored pulse FW is generated from a, and IFIItT-
When yl is turned on and the common electrode C is connected to VDDK, the constant current circuit B operates. On the other hand, analog switch B11 is turned on], 1FIT-7F of constant current circuit B,
The gate voltage of the analog switch s14゜eta
--s2. supplied to On the other hand, gate oilway G-san~
The input terminals a to g of Gll each have a display segment e.
0 supplied from the output decoder DI indicating the display state of a-Bg (for example, display segment) Sa.

When coloring only 8b and decoloring the pond display segment BC-Bg, terminals a and b are 11" and terminals C to g are 1".
It becomes 0#. Since the terminals a and b are 11", the analog switch 81.B is turned on, and the colored display terminal 8a is turned on.
8b is electrically connected.

The colored pulse FW passes through the nine gate circuit G@*Gl and the analog switches S14+S1 are turned on.

IPII+Ding-'14*'E? 1@ works. Therefore, a current flows from the IF ICT-ys through the common electrode C1 display segments) 8a, 8b and the IFT-IP14e'II, and the display segments) 8a, 8b are driven with a constant current and colored. At this time, display segments) 8a, 8
bij are short-circuited, so even if there is some difference in the area* of the two, the coloring 11f of the two is uniform. this is,
Electrochromic materials have the following properties. The electrochromic material itself has a resistance value, and when charge is accumulated between it and the common electrode and the potential exceeds a predetermined value, the resistance value increases in proportion to this potential. The area of the rounded, shorted display segment Kl! -, the one with a small area first reaches a predetermined potential and its resistance value increases, and a potential difference is created between this one and the one with a large area. Due to this potential difference, 11EflL flowing into the small area crosses the short circuit resistance and flows into the large area. Therefore, the current flowing to the large area increases, the potential of each display segment is made uniform, and the color density is made uniform.

In this way, the rounding that is colored by the constant current section 111,
The change in resistance of the display segment can be utilized, thereby making it possible to make the color density uniform.

Since the amount of injected charge can be changed simply by changing the current value or the coloring pulse width, panels of various sizes can be created by changing the width of the decoloring pulse and the coloring pulse depending on the panel size of the electrochromic display device. It can be applied to This example is shown in Figure 5, in which a ROM (read only memory) M containing 10 gamuts of data specifying a plurality of types of pulse widths is added to the configuration shown in FIG. According to this, display with sufficient coloring density can be performed on a panel of any size simply by selecting data according to the panel size.

The configuration of the pulse generation circuit PG in this case is as follows:
It is recommended to install a counter that receives the clock pulse from the minute 14 cloud and counts the pulse width, and a matching circuit that matches the contents of this counter with the data from the RQM. Coloring and decolorizing pulses are obtained.

In addition, in the above embodiment, a constant voltage flL is applied to coloring and decoloring and t.
Although the decoloring is carried out by the manual method, it is also possible to perform the decoloring by driving at a constant voltage.

As described above in detail, according to the present invention, colored display segments are electrically connected to each other to form a constant current section, so that changes in the number of colored display segments, temperature changes, and 1 m source pressure can be achieved. It is possible to uniformly color the product to a certain level of quality without being affected by shadows caused by other factors.

[Brief explanation of drawings]

The first button shows an embodiment of the present invention. Figure 2 shows the main parts of Figure 1 in detail. Toy with a hook. A... Electrochromic display device, B... Constant current circuit, 8a-13g... Display segment, C
...Common electrode, G, %G-...Gate path. 5s-8tt...Another party switch. (Applicant: Seiko Co., Ltd.) Agent: Patent Attorney Mogami

Claims (1)

[Claims] A plurality of display segments made of electro-chromic material and a common IH are provided, a control path 41- is electrically connected to the colored display segments, and a constant current is passed between the colored display segments and the common electrode. Constant voltage a for coloring
A drive circuit for an electrochronic display device consisting of an oil passage.