JPS6339687Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a display driving device that dynamically drives a liquid crystal.

Conventionally, when driving a liquid crystal display device configured by arranging electrodes in a matrix with liquid crystals interposed between them, the effect of the voltage applied between the electrodes of the pixels that are to be displayed causes non-display between the electrodes that should normally be non-display. There was a drawback that a voltage higher than the display voltage was applied, resulting in a display caused by so-called crosstalk. In response, attempts have been made to eliminate crosstalk by devising the voltage waveforms to be applied to the row and column electrodes, but these methods require complicated circuit configurations to generate special waveforms, or require settings. There were drawbacks such as an increase in the range of voltage values.

Therefore, the present invention provides a switching element corresponding to each liquid crystal display element, closes the switching element and applies voltage to the liquid crystal display element that should display, and applies voltage to the liquid crystal display element that should not display. provides a liquid crystal display device in which the switching display is opened and no voltage is applied, thereby eliminating the above-mentioned conventional drawbacks.

An embodiment of the present invention will be described below based on the drawings. FIG. 1 shows a liquid crystal display device with a matrix of 3 rows and 3 columns, in which 1 to 9 are liquid crystal display elements constituted by row and column electrodes with liquid crystal interposed therebetween;
-18 are switching circuits, for example, analog switches, connected in series with the liquid crystal display element. Reference numeral 19 denotes a clock pulse generating circuit, and in response to this output pulse, the timing pulse generating circuit 20 sequentially generates pulses A, B, and C shown in the third figure at terminals a ₁ , a ₂ , and a ₃ . A second signal supply circuit is configured. The drive pulse generating circuit 21 receives the output pulses from the clock pulse generating circuit 19, and continuously generates pulse trains D, E and F shown in FIG. 3, some of which are shown at the output terminal _b1 . A pulse train having a half cycle phase difference from the same pulse train is generated at the output terminal _b2 . Reference numeral 22 denotes a switching selection circuit, which outputs selection outputs of the switching circuits in each column from the left side of the first diagram to terminals Z ₁ to Z ₃ in synchronization with each output pulse of the terminals a ₁ to a ₃ of the timing pulse generation circuit 20; That is, a 3-bit parallel output is generated. 23 to 31 are gate circuits. The gate circuits 23 to 31 and the timing pulse generation circuit 20 constitute a first signal supply circuit.

In the above configuration, when the pulse _{A shown} in _{FIG .} occurs. Pulses B and C of a ₁ and a ₂ in the same figure are applied to terminals _{a 2} and a 3 below.
occur sequentially, the column terminals X ₂ and
Pulses E and F are generated sequentially at _X3 . Note that among the terminals a ₁ to _{a 3} , the terminals to which no pulse is generated are held at the logical value "0". Therefore, for example, when the terminal a ₂ has a logical value of "0", the gate circuit 24 is closed and the gate circuit 27 is opened, so that the pulse generated at the terminal b ₂ is transferred to the column terminal X ₂ of the gate circuit 30.
occurs in The row terminals Y ₁ to _{Y 3} shown in the first diagram are supplied with the output pulse of the terminal b ₂ shown in the second diagram.

Therefore, the liquid crystal display elements 4, 6 and 8 shown in FIG.
The case of lighting up will be explained. When the pulse A shown in the third figure is generated, the pulse D shown in the third figure is applied to the column terminal X ₁ shown in the first figure, and the remaining column terminal X ₂
and X ₃ , since the outputs of terminal a ₂ and terminal a ₃ have logical values “0” and “0”, the gate circuit 2
7 and 28 are opened, and the half-period phase-shifted pulses occurring at terminal _b2 are applied. On the other hand, a logic value "1" is generated at the terminal _Z2 of the switching selection circuit 22,
A logic value "0" is generated at the other terminals _Z1 and _Z3 . Here, it is assumed that the switching circuits 10 to 18 are closed when the logic value is "1" and open when the logic value is "0".
Accordingly, the above logic output closes the switching circuit 13 shown in the first diagram and applies the pulse G shown in the third diagram to the liquid crystal display element 4, so that the liquid crystal display element is turned on. Note that the remaining liquid crystal display elements 1 and 7 are turned off because the switching circuits 10 and 16 are open, so that no voltage is applied thereto. Furthermore, the switching circuits 14 and 15 are closed, but the pulses generated at the terminals X ₂ and X ₃ and the terminal Y ₂ are the output pulses of the terminal b ₂ and are both in phase, and the liquid crystal display elements 5 and 6 are turned off. ing. Next, when the pulse B shown in the third figure is generated at the terminal a ₂ , the terminals Z ₁ , Z ₂ and Z ₃ of the data generation circuit 22 have the logic value "0", respectively.
"0" and "1" are generated, switching circuit 17 is closed and switching circuits 11 and 14 are open. Therefore, the liquid crystal display element 8 lights up.

The other liquid crystal display elements 2 and 5 are off. Note that among the terminals X ₁ to _{X 3} , the switching circuit provided in the column corresponding to the non-selected terminal also connects to the terminal Z ₁
~ When the logic value of any of Z ₃ becomes "1", it is closed, but since the same phase pulse is applied to both electrodes of the liquid crystal display element connected to the switching circuit, the voltage applied to the liquid crystal is zero. become. Therefore, it will not light up. Now, when the pulse C shown in the third figure is generated at the terminal _a3 , the liquid crystal display element 6 is turned on in the same manner as described above. The same operation is repeated thereafter, and the liquid crystal display elements 4, 8, and 6 are kept lit.

In this embodiment, the column terminals X ₁ to X ₃ and the row terminal Y ₁
Although the pulses applied to ~ _Y3 have been described as being limited to specific ones, the pulses are not necessarily limited to these. Any pulse voltage that has a relationship between when the liquid crystal display element is turned on and off depending on the difference between the pulse voltages supplied to the column terminals X ₁ to X ₃ and the row terminals Y ₁ to _{Y 3} may be used. .

As detailed above, the present invention configures a matrix circuit by a series circuit of a liquid crystal display element and a switching circuit, controls switching of the switching circuit, and sequentially selects row or column terminals to apply a signal. Since the lighting of the liquid crystal display element is controlled based on the difference between the signal and the signal applied to the remaining terminals, a liquid crystal display device that does not cause crosstalk can be obtained. In particular, no crosstalk occurs regardless of the number of digits. Further, except for the provision of a switching circuit, the circuit configuration is simple and does not require generation of special waveform pulses.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, FIGS. 1 and 2 are electrical circuit diagrams, and FIG. 3 is a time chart showing pulse waveforms of the main parts of FIG. 1. 1-9...Liquid crystal display element, 10-18...Switching circuit, 20...Timing pulse generation circuit, 2
2...Switching selection circuit.

Claims (1)

[Scope of utility model registration request] A series circuit is formed of a liquid crystal display element and a switching circuit, one terminal and the other terminal of each series circuit are connected in common to form a matrix circuit, and one terminal of a row and a column of this matrix circuit are connected in sequence. A first signal supply circuit is provided which supplies different signals to the selection terminal and the non-selection terminal, respectively, and lights up the liquid crystal display element based on the difference between the signal supplied to the selection terminal and the signal supplied to the non-selection terminal. A second signal supply circuit is provided for supplying a signal capable of turning off the liquid crystal display element due to a difference between the signal and the signal to the other terminals of the row and column, and in synchronization with the selection of the first signal supply circuit, A liquid crystal display drive device equipped with a switching selection circuit that controls the opening and closing operations of switching circuits forming a series circuit.