JP2003140180A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent burning of a liquid crystal display screen while both static driving and multiplex driving are conducted. SOLUTION: The liquid crystal display device is provided with a liquid crystal display region 15 having a first liquid crystal display section 14 which is statically driven through a first wiring group 24 and a second liquid crystal display section 20 which is multiplex driven through a second wiring group 30. Then, if Y [m] is a minimum distance between the wiring arbitrary extracted from the groups 24 and 30 and Xm [V] is the driving voltage to be applied to the group 30, when manufacturing the device, a design is made to satisfy an equation Y>=(411.77×10<-6> )Xm-(4588×10<-6> ).

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a liquid crystal display device, which is preferably applied to the manufacture of a color liquid crystal display device, and more particularly to an STN liquid crystal display device. 2. Description of the Related Art In recent years, there has been an increasing demand for higher precision and lower power consumption of liquid crystal display devices used for liquid crystal display devices such as mobile phones and PDAs. In order to reduce the power consumption, for example,
The screen display of the liquid crystal screen of the mobile phone is such that the display unit which is always displayed is statically driven through the first wiring group, and the display unit which is displayed only at a specific time such as a telephone call is the multiplex drive through the second wiring group. , The driving system is separated. [0004] That is, at the time of standby, for example, not during a call, power consumption is suppressed by adopting a structure in which only the static drive is driven. [0005] However, during a call or the like in which both the static drive and the multiplex drive are driven, the drive voltage output to the first and second wiring groups for each drive is required. In some cases, these may have an undesired effect on each other, causing an undesired potential difference between the first and second wiring groups. [0006] Then, the liquid crystal material and the alignment film are damaged by the potential difference, and display unevenness such as burn-in occurs on the liquid crystal display screen. [0007] Therefore, it has been desired to develop a technique for technically solving the above-mentioned problems. [0008] In order to solve the above problems, the present invention has the following structural features. That is, in the liquid crystal display device of the present invention, the first liquid crystal display section is statically driven through the first wiring group, and the second multiplex drive is multiplexed through the second wiring group.
A liquid crystal display area having a liquid crystal display portion is provided, and a shortest distance Y [m] between wirings arbitrarily extracted from each of the first wiring group and the second wiring group is determined by a driving voltage applied to the second wiring group. When expressed as Xm [V], it has a configuration satisfying the following equation (1). Y ≧ (411.77 × 10 ⁻⁶ ) Xm− (4588 × 10 ⁻⁶ ) (1) With such a configuration, both the static drive and the multiplex drive are driven. At this time, a structure in which voltages applied as drive waveforms to each of the first and second wiring groups do not affect each other can be provided. As a result, both driving can be performed normally, and display unevenness due to burn-in of the liquid crystal display screen can be prevented. An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the drawings merely schematically show the shapes, sizes, and arrangements of the components so that the present invention can be understood, and therefore, the present invention is not limited to the illustrated examples. Referring to FIGS. 1A and 1B, the liquid crystal display device of the present invention will be described. First, FIG. 1A shows a configuration example of a display screen of an STN liquid crystal display device to which the present invention is applied. still,
The present invention is not limited to the STN liquid crystal display device, but can be applied to any suitable liquid crystal display device. According to this embodiment, the liquid crystal display area 15 provided in the liquid crystal display device is not particularly limited, but as an example, an antenna mark 10 or the like which is always displayed is provided above the liquid crystal display area 15. A first liquid crystal display unit 14 having a remaining battery mark 12 is provided. In the lower area of the liquid crystal display area 15,
Only during a call, the other party's display section 16 and the talk time display section 18
, A second liquid crystal display unit 20 is provided. Next, FIG. 1 shows an example of a configuration of a wiring group for displaying on the first display section 14 and the second display section 20.
It is shown in (B). The first liquid crystal display section 14 has a first wiring group having a segment electrode wiring 22 drawn out for each pixel (not shown) and a common electrode wiring (not shown) arranged opposite to the segment electrode. 24 is driven statically by applying a drive voltage Xs. Further, the second liquid crystal display section 20 includes common electrode wirings 26 (26a, 2a) arranged orthogonally to each other.
6b, 26c, 26d) and the segment electrode wiring 28 (2
8a, 28b, 28c, 28d), the multiplex driving is performed by applying the driving voltage Xm to the second wiring group 30. In the present invention, the first wiring group 2
Arbitrary wiring was extracted from each of the fourth and second wiring groups 30, and the shortest distance Y between the wirings was examined as follows. That is, as shown in FIG. 1 (B), the extracted first wirings 22 are located beside the second liquid crystal display unit 20.
Substantially parallel to the segment electrode wiring 28, that is,
It is assumed that it is drawn out in a direction orthogonal to the common electrode wiring 26. In this case, the segment electrode wiring 22 is extracted as an arbitrary wiring from the first wiring group 24, and the common electrode wiring 26b is extracted as an arbitrary wiring from the second wiring group, and the shortest distance between these wirings is Y. This distance Y is a distance in the extending direction of the common electrode wiring 26. The shortest distance Y and the driving voltage Xs
And the relationship with the driving voltage Xm were examined under the following conditions. <Condition 1> Driving voltage Xs 2.4 [V] Driving voltage Xm 12.6 [V] Shortest distance Y 6 × 10 ^-5 [m] <Condition 2> Driving voltage Xs 2.4 [V] Driving Voltage Xm 12.6 [V] Shortest distance Y 6 × 10 ^-4 [m] <Condition 3> Drive voltage Xs 2.4 [V] Drive voltage Xm 16.0 [V] Shortest distance Y 2 × 10 ^-3 [ m] As described above, by changing the shortest distance Y and the driving voltage Xm, it was examined whether or not display unevenness such as image sticking occurred on the liquid crystal display screen at this time. The driving voltage Xs under each condition is the driving voltage Xs in a general portable telephone, Xs = 2.4.
[V]. Table 1 shows the results. [Table 1] FIG. 2 shows the relationship between the shortest distance Y and the driving voltage Xm at this time based on Table 1. From the graph of Table 1 and FIG. 2, the driving voltage Xm
It can be seen that when the minimum distance Y is set to at least 6 × 10 ⁻⁴ [m] or more, display unevenness such as burn-in can be avoided. When the drive voltage Xm is designed to be 16.0 V, the shortest distance Y must be at least 2 × 10
^It can be seen that display irregularities such as burn-in can be avoided by setting it to ^-3 [m] or more. Therefore, based on the above results, the following expression (1) can be derived as a conditional expression capable of preventing display unevenness. What is necessary is just to design the liquid crystal display device so as to satisfy the conditional expression (1). Y ≧ (411.77 × 10 ⁻⁶ ) Xm− (4588 × 10 ⁻⁶ ) (1) By the way, a mobile phone or the like that drives both static driving and multiplex driving is actually used. , Drive voltage X
In many cases, m is designed according to a standard within a range of 12.6 V ≦ Xm ≦ 16 V. Therefore, in practice, the shortest distance Y is 6 × 10 ⁻⁴ [m] ≦ Y ≦ 2 × 10 ^{−3 in the} conditional expression (1).
It is preferable to design within the range of [m]. Therefore, the shortest distance Y between the wirings extracted from each of the first wiring group 24 to be statically driven and the second wiring group 30 to be multiplex driven is determined by the equation (1) according to the design value of the driving voltage Xm. ), It is possible to prevent the occurrence of display unevenness by separating by a predetermined distance. In the embodiment of the present invention, the first
The combination of wirings arbitrarily extracted from each of the second wiring group and the second wiring group is not limited to the above. Therefore, the present invention can be applied by combining any suitable conditions. As is apparent from the above description, according to the present invention, the shortest distance between the wirings arbitrarily extracted from each of the first and second wiring groups can be increased by a predetermined distance. In addition, when both the static drive and the multiplex drive are driven, display unevenness due to burn-in of the liquid crystal display screen or the like can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a configuration of a liquid crystal display unit according to an embodiment of the present invention. FIG. 2 is a diagram showing a relationship between a driving voltage Xm and a shortest distance Y according to the embodiment of the present invention. [Description of Signs] 10: Antenna mark 12: Remaining battery mark 14: First liquid crystal display section 15: Liquid crystal display area 16: Call partner display section 18: Talk time display section 20: Second liquid crystal display section 22: Segment electrode Wiring 24: first wiring group 26, 26a, 26b, 26c, 26d: common electrode wiring 28, 28a, 28b, 28c, 28d: segment electrode wiring 30: second wiring group

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/35 G09F 9/35 F term (Reference) 2H089 HA33 QA16 RA10 SA17 2H092 GA33 GA41 NA01 NA29 QA10 2H093 NA01 NA06 ND12 NE03 NF13 NH18 5C094 AA03 AA22 BA08 BA45 CA14 CA19 EA07 EA10 HA10 JA08

Claims (1)

Claims: 1. A first liquid crystal display section statically driven via a first wiring group and a second liquid crystal display section multiplex driven via a second wiring group comprise a liquid crystal display area. Wherein the shortest distance Y [m] between wirings arbitrarily extracted from the first wiring group and the second driving wiring group is the second distance.
A liquid crystal display device characterized by satisfying the following expression (1) when a drive voltage applied to a wiring group is represented by Xm [V]. Y ≧ (411.77 × 10 ⁻⁶ ) Xm− (4588 × 10 ⁻⁶ ) (1)