JPS58137883A - Liquid crystal display body - 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] Currently, TN using two polarizing plates and nematic liquid crystal.
(Twisted-nematic) liquid crystal displays are commonly used in calculators, watches, and to provide one or two line character displays.

However, since these are driven by a multiplex method using a voltage averaging method, they are not suitable for display bodies that require higher density. Particularly recently, there has been a strong demand for high-density, flat panels for use in combiator terminals, and therefore, it has been proposed to develop a display using a smectic phase that can be expected to achieve higher density in place of the conventional TN-type liquid crystal.

For example, attempts have been made to display cassictors, graphics, or moving surfaces by controlling the ordered parts and random states of smectic physiognomy using both means of heat and voltage application.

The principle can be explained by the diagram schematically shown in FIG.

Heat the smectic liquid crystal and clear l India T.

If the value is above, the liquid crystal becomes isotropic. (101) At this time, when the liquid crystal is rapidly cooled without applying a voltage, the liquid crystal passes through the nematic phase (102) and becomes a random smectic phase (103), causing light scattering with respect to the peripheral light. On the other hand, if cooling is continued while a voltage higher than the threshold voltage vth of the nematic liquid crystal that appears during cooling is applied, a smectic phase (105) with high orderliness that does not cause light scattering is formed. Appear.

The principle of this display is to control and display this light scattering state and the two smectic states without light scattering by a combination of heating/cooling and the presence/absence of voltage. As a heat source, in addition to methods using lasers, methods using resistance heating are also being considered.

Specifically, the following matrix display bodies have been proposed using a resistance heating method.

The liquid crystal is linearly heated by one resistance wire shown in FIG. 2 (201). A number of these heating resistance wires are arranged on the substrate, and the ROW electrodes, ROW-1, Rot-
2, ROW-5, . . . are formed. The video signal is sent to the Otumn electrodes 0-1, O-2, and O-2 of the display body.
It is applied to O-5, . . . 1 .

Addressing is performed line sequentially, one by one.

A heating pulse is applied to the first Rot-2in@Row-1, and the video signal is sequentially stored in the shift register while the top of the tin is heated uniformly. At the same time as the heating pulse goes to art, the video signal goes to 0.
scattered or transparent dots are formed depending on the signal. This signal is applied only during the cooling period after the application of the heating pulse ends (actually, it takes a nematic state and is valid only during that period).

For example, 5cm thick, 2 glass substrates, metal for the Rowll electrode, 7umn for the electrode, 250RO'W and 2400otumn, pitch α375 (electrode width (L3
25) An example of a prototype character cell with an effective area of 94 x 90 has been reported, and according to it, 1 ti!
It has been reported that the writing speed is approximately 108cm and the power consumption during writing is 15W.

The writing speed is determined by the thermal response characteristics of the substrate, and the cooling speed is particularly important. Therefore, in order to shorten the address time and ensure high-speed response, it is necessary to improve this thermal response, especially the cooling speed.The above-mentioned display requires several seconds to display one screen. be. Regarding power consumption, since this liquid crystal has a memory function (thermal hysteresis phenomenon), it requires 15W of power for only a few seconds when writing, but after writing is finished, no power is required. On average, when used as a combination terminal, the power consumption is less than 5W. However, the extremely large amount of power required during writing causes circuit and design problems, which, combined with the slow response speed, hinders the application of this method.

An object of the present invention is to take these points into consideration and develop a high-speed, low-power, large-capacity display.

A more detailed explanation of the display body of the present invention will be given below based on examples.

FIG. 3 is a diagram showing the principle of a drive circuit for a hot-wire writing type display. The video signal output from the character generator (305) passes through a latch (304), is introduced as data into a shift register (306), and is further stored in a latch (307). meanwhile,
The control circuit (311) outputs a scan signal of 1
It is input to the shift register # (312) on the 0w side and is passed through the driver to the first 1t on the ROW electrode side of the liquid crystal display.
Heating in・(R-1). Provide heating pulses.

At the same time as the heating pulse finishes applying, in synchronization with the control circuit, the video signal stored in the latch (307) is connected to the entire 00 L um h
O1e O@ ”... is applied to OfL, and the first 1 time (R-1) is written. While the video signal is applied to Oo l um n, the heating pulse applied to the 10W side is Next Row tine (R
-2) and heats R-2time. R
While −2 heating pulses are applied, the video signal is
Stored from shift register to latch, heating pulse O
At the same time as ff, the second Line (R-
2) is applied as a data signal. In this way, the writing is sequentially continued in the order of R-5, R-4, . . . until one screen is written. Regarding the writing speed, as described above, the faster the thermal response speed of each tin, the faster the writing can be completed, and the greater the number of tinos that can be written in a unit time.

The heating speed increases as the applied voltage increases, but the cooling speed depends on natural heat dissipation phenomena and is strongly influenced by the heat capacity thermal conductivity of the material around the heat dissipation part or the temperature difference with the surroundings. It goes without saying that the larger the area of the heating substance, the greater the power consumption required for heating. If you take these things into consideration, the conventional simple tin
We have noticed that the e-heating method has an electrode configuration that has extremely high losses in terms of speed and power consumption. The present invention
It provides a display with low power consumption and high response speed.0 For example, if a cell is constructed using the conventional method, the specific resistance will be 2.6 x 10''・Ω・Using the country's At,
Thickness: L24μ, width: 1525m, length: 90m
15 W of power was required to heat the pole "t'Lf&. However, the dot part required for actual display is 78 wm for the entire length of 90 fins, so it is difficult to heat just that dot part. It can be said to be ideal.

For example, a method using a laser is close to that. While approximately 13 W of power is required to heat only the effective display section, this method consumes 15 W of power.

In other words, unnecessary parts are also heated, which not only causes power loss but also worsens cooling speed.

FIG. 4 is a principle diagram of the electrode structure of the present invention, in particular, a ROW electrode to which heating (lux) is applied.

As shown in FIG. 4, the Row electrode consists of a resistance line with a width of 1325 μm in which different resistance values R and r are alternately repeated. Specifically, At having a resistivity of 'L6X10'''-Ω- is deposited on the glass substrate 501 at a radius of α325μ, and the thickness of the deposited aluminum is α12μ for the R portion and (L48μ for the r portion).
It becomes. Also, the length of the R part is (L525μ, the r part is α
05μ, and the R portion corresponds to the counter electrode OOtu van electrode. FIG. 6 schematically shows this state. 250Rov, 2400otu same as the prototype example mentioned above
mn, and the effective area is 94x90-, the series resistance of Row/in is R” (Rtt + Rtt +++++++*++mmR
, fi ) + (r11+rs*+"-...rt, 3
-t) Rx, t=Rx, t=...””Rt, nl,
1 1, 1 1, 8 1 chant + 1-', R* n・(Rtt + rts).

In the case of the Att pole of the dimension mentioned above, RH+ 4
Ω, r11+TwΩ, and from n = 240, R = 5-4. It becomes OΩ.

Applied voltage 27. to this resistance wire. When a voltage of OV is applied, [L5A(7) current flows and (L525X(Li2S
- Necessary power (heat) is supplied to the dot part.

The total power consumption at this time was W = 54X [L5 = 155 watts, which is a value close to the ideal power consumption.

A mask evaporation method was used to fabricate At1l, starting with 0
．． After depositing the At wire with a thickness of 12 μm, additional vapor deposition W was performed on the r portion to a thickness of α48 μm using a mask with a hole corresponding to the low resistance r portion. As a result, an electrode structure corresponding to FIG. 4 was obtained. The prototype cell using this method consumes only 1 and 5 W of power, and has a cooling speed (approximately 20% improved compared to conventional ones. As a result, the write time, which conventionally required 171*@approximately 10 ssec, has been reduced to 8 ssec). It became possible to write 25011n@ at 20 degrees.

[Brief explanation of the drawing]

Figure 1: Principle diagram of thermo-electrical writing/erasing method for display bodies using a multi-smectic phase (1) Thermal hysteresis under voltage application (II)
Thermal hysteresis in a non-voltage state Figure 2: Electrode configuration of matrix address display paddle using smectic phase, thermoelectric, write/erase method 201... Metal electrode (Row electrode) 202 ・X TO transparent Electrode (aotumn [WR)
Figure 3: Block diagram of the drive circuit for the matrix address display used in this embodiment 301...optr 302...frame memory 503...character, generator 304...
・For carage energy, latch 305...parallel-serial conversion circuit 306...
Data signal shift register 307... Data latch 308... Data signal driver 309... Oscillator 310... Address, counter 311... Control unit S12... Scan side, shift register 513 ...
Driver 514... Matrix display Fig. 4 8 Electrode configuration principle diagram used in the present invention R... Compatible with display dots, heating resistor electrode portion R... Compatible between dots, Ro
t-electrode Figure 5: Electrode sectional view 501...Substrate glass 502...Lead portion 503...Supporting display dots, heating resistance electrode 504...
・Row electrode 601 for between dots...Row electrode 602...Otumn electrode R%...High resistance part rs W for display dots...Low resistance electrode component for between display dots Applicant Suwa Co., Ltd. Seikosha Agent Patent Attorney Tsutomu Mogami

Claims (1)

[Claims] By controlling the phase transition phenomenon of smectic liquid crystal using heat and electric field, each heating electrode line is connected to a low-resistance part and a high-resistance part in a matrix or address display that displays characters, numbers, etc. A liquid crystal display body characterized in that it is formed by repeating, and the repeating period is synchronized with the spacing of column electrodes.