JPH10197845A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the liquid crystal display device which can be driven with low power consumption. SOLUTION: As a driving signal Sd of the liquid crystal display device which is driven on a time-division basis, an image data signal SEGm and an effective voltage control signal Sc following it are inputted in one frame time T1 and in the timing of the end of the image data signal SEGm, a uniform voltage within the voltage range of a control signal system is applied to a liquid crystal display panel on the basis of the effective voltage control signal Sc and used as a liquid crystal driving voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-voltage, low-power-consumption liquid crystal display device represented by a portable terminal.

[0002]

2. Description of the Related Art In the recent trend of low power consumption in portable equipment terminals, MPUs (Micro Process-ing Units) and the like have reduced the voltage for controlling the equipment itself, and have controlled signals for liquid crystal display devices. The system is also controlled at the same low voltage. Hereinafter, an example of a conventional liquid crystal display device will be described with reference to the drawings. The basic configuration of a liquid crystal display device is generally as shown in FIG. 3, and FIG. 3 is a block diagram schematically showing the outline of the liquid crystal display device. In the drawing, 1 is a liquid crystal display panel, 2 is a scanning signal line, 3 is a data signal line,
4 is a liquid crystal driving driver, 5 is a lighting display point, and 6 is a non-lighting display point. The drive signal added to this is as shown in the signal waveform diagram of FIG.
T ₁ is one frame time, [COM _n ] ( _n is a positive integer) is a scanning signal applied to the scanning signal line 2, [COM _{n + 1} ] is a next scanning signal in the same frame, and is hereinafter referred to as an arrow X direction. , And reaches [COM _{n + K} ] ( _K is a positive integer) (not shown). [SEGm]
The data signal applied to the data signal line 3, V ₁ is the peak value of these signals. The state in which the data signal [SEGm] is being scanned by the scanning signal [COM _n ] is referred to as [COM _n ] − [S
EGm] and a state in which the data signal [SEGm] is being scanned by the scanning signal [COM _{n + 1} ] are represented as [COM _{n + 1} ] − [SEGm].

As is apparent from this signal waveform diagram, 1
In frame time T _1, the data signal is scanned by the scanning signal, but it is to display the screen of one frame in the liquid crystal display panel 1, in this case, to obtain a voltage of effective value required for driving the liquid crystal To obtain the peak value V ₁
It is necessary to separately provide a booster circuit using a DC-DC transformer circuit and a power supply circuit for generating a liquid crystal driving voltage, thereby obtaining a liquid crystal driving voltage.

[0004]

However, in such a conventional configuration, a DC-DC circuit for securing a liquid crystal driving voltage even if the voltage of a control signal system is reduced to reduce power consumption. Therefore, there has been a problem that a booster circuit or a separate power supply is required, and low power consumption cannot be expected much as a liquid crystal display device.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a liquid crystal display device capable of driving with low power consumption.

[0006]

According to the liquid crystal display device of the present invention, an image data signal and an effective voltage control signal continuous with the image data signal are input within one frame time as drive signals in the time-division driving. At the end timing, a uniform voltage within a voltage range of the control signal system is applied to the liquid crystal display panel based on the effective voltage control signal, and this is used as a liquid crystal drive voltage.

According to the present invention, a liquid crystal display device which can be driven with low power consumption without requiring a booster circuit such as a DC-DC transformer circuit is obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. Note that the same reference numerals are used for the same parts as those of the conventional one.
Since the basic configuration of the liquid crystal display device in the present embodiment is the same as that shown in FIG. 3, the liquid crystal display device will be described with reference to this. FIG. 1 is a signal waveform diagram in Embodiment 1 of the liquid crystal display device of the present invention,
In the figure, COM _n ( _n is a positive integer) is a scanning signal applied to the scanning signal line 2, COM _{n + 1} is the next scanning signal in the same frame, and is sequentially scanned in the direction of arrow X, and COM _{n + K (K} is a positive integer) but is the result in (not shown), different from the one of the prior art, comprises an effective voltage control signal Sc which is continuous with this position of the timing T ₂ of the image data signal ends. SEGm is a data signal applied to the data signal line 3. The state in which the data signal SEGm is being scanned by the scanning signal COM _n is COM _n −SEGm, and the data signal SEGm is the scanning signal COM _{n + 1}
Is represented as COM _{n + 1} −SEGm. Sd indicates the whole image of the drive signal applied to the liquid crystal display panel 1, and includes a data signal SEGm and an effective voltage control signal.
Sc is a continuous form at the timing T ₂ in _one frame time T.

Next, the operation will be described. In one frame time T ₁ , first, after the data signal SEGm is written, the scanning signal COM _{n in} the period of the end timing T ₂ is written.
Effective by the voltage control signal Sc, all display points 5,6, all the scanning signal lines 2 and the data signal lines 3 are the same scan signal level on the liquid crystal panel 1 in the period of the timing T _2, the same data contained in the It is set to be at the signal level. In this case, a voltage is uniformly applied to the liquid crystal display panel, which functions as an effective voltage required for driving the liquid crystal.

As described above, according to the present embodiment, it is possible to apply a uniform voltage to the liquid crystal display panel by the effective voltage control signal, and this uniformly applied voltage is necessary for driving the liquid crystal. Since it functions as an effective effective voltage, an external circuit such as a booster circuit using a DC-DC transformer circuit as in the prior art is not required, and power consumption can be reduced.

[0011]

As described above, according to the present invention, a uniform voltage is applied to the liquid crystal display panel within one frame time by the effective voltage control signal continuous with the image data signal at a timing corresponding to the end of the data signal. Since the uniformly applied voltage functions as an effective voltage necessary for driving the liquid crystal, an external circuit such as a booster circuit using a DC-DC transformer circuit as in the conventional case is not required, and An advantageous effect that low power consumption driving can be achieved with a voltage can be obtained.

[Brief description of the drawings]

FIG. 1 is a signal waveform diagram according to a first embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a signal waveform diagram in a conventional liquid crystal display device.

FIG. 3 is a block diagram schematically showing a basic configuration of a general liquid crystal display device.

[Explanation of symbols]

1 ... liquid crystal display panel, 2 ... scanning signal lines, 3 ... data signal line, 4 ... liquid crystal driving driver, 5 ... lighting display points, 6 ... unlit display point, T ₁ ... 1
Frame time, T ₂ ... timing, COM _n , COM _{n + 1} ...
Scan signal, SEGm: data signal, Sc: effective voltage control signal, Sd: drive signal.

Claims (1)

[Claims] 1. A liquid crystal display device including a liquid crystal panel which performs at least two-division or more time-division driving, and means for applying a data signal and a continuous effective voltage control signal to the data signal as drive signals within one frame time. Means for applying a uniform voltage within the voltage range of the control signal system to the liquid crystal panel based on the effective voltage control signal at the end of the data signal, and using the uniform voltage as a liquid crystal drive voltage. A liquid crystal display device characterized by the above-mentioned.