JPH02127617A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE:To make a gradational display more than gradations determined by the performance of liquid crystal and a driving IC by sandwiching liquid crystal layers, scanning electrode plates, and a signal electrode plate by two polarizing plates are varying signal voltages applied to the two liquid crystal layers indivisually in liquid crystal units. CONSTITUTION:The two liquid crystal layers 13 and 15 are arranged opposite each other at an interval, the scanning electrode plates 12 and 16 have thin and long scanning electrodes arrayed on one plane in parallel, and the signal electrode plate 14 has thin and long signal electrodes arrayed at right angles to the array direction of the scanning electrodes; and the liquid crystal layers 13 and 15, scanning electrode plates 12 and 16, and signal electrode plate 14 are sandwiched between the two polarizing plates 11 and 17 and the signal voltages applied to the liquid crystal layers 13 and 15 are varied individually by the liquid crystal layers to make the gradational display. Consequently, the gradational display more than the gradations determined by the performance of the liquid crystal and driving IC can be made.

Description

[Detailed description of the invention] <Industrial application field> This invention relates to liquid crystal display panels.

<Prior Art> Conventionally, there is a liquid crystal display (hereinafter referred to as LCD) panel as shown in FIG. 4 or FIG. 5.

FIG. 4 shows an example of the structure of a TN-LCD panel. This TN-LCD panel includes a liquid crystal layer 43, a scanning Tit electrode plate 42 and a signal electrode plate 44 arranged to sandwich this liquid crystal layer 43, and outer sides of the scanning electrode plate 42 and signal electrode plate 44, respectively. Polarizing plate 41 arranged in
．． It consists of 45. Both the scanning electrode plate 42 and the signal electrode plate 44 are transparent, and a scanning electrode is provided on the liquid crystal layer side of the scanning electrode plate 42, and a signal electrode is provided on the liquid crystal side surface of the signal electrode plate 44. It is being

Now, the light incident on the polarizing plate 41 is transmitted only in a specific direction, and is incident on the liquid crystal layer 43 via the scanning electrode plate 42. In the absence of an electric field, the liquid crystal molecules have a twisted structure that is twisted by 90 degrees parallel to the plate surface, but when an electric field is applied, the arrangement changes to perpendicular to the plate surface.

Therefore, in the part where there is no electric field, the polarized light reaches the polarizing plate 45 with a twist of 90 degrees, and in the part where the electric field is applied, the polarized light reaches the polarizing plate 45 with the original polarization. Here, for example, if the polarizing direction of the polarizing plate 45 is set in the same direction as that of the polarizing plate 41, the light passing through the non-electric field portion is blocked and becomes dark, and the light passing through the electric field portion is transmitted and appears bright. In this way, 711i+u42.
By controlling 44, a black and white screen can be displayed.

Figure 5 shows D, which is currently attracting attention for its high contrast.
This figure shows an example of the groove structure of the S T-L CD panel. This DST-LCD panel has a sharper contrast by increasing the twist angle of the liquid crystal molecules compared to the TN-1 and CD panels, but since the transmitted light is colored, the liquid crystal layer 53 that applies the electric field is Color compensation is performed by adding another liquid crystal layer 55 whose twist is in the opposite direction. No electric field is applied to the liquid crystal layer 55 for color compensation.

If the voltage applied to the liquid crystal is weakened, the alignment of the liquid crystal molecules will not change sufficiently, and the original polarized light will mix with the twisted polarized light, and some of the light will be blocked by the polarizing plate and transmitted. rate decreases. Therefore, gradations can be added to the display by changing the strength of the applied voltage. The applied voltage is controlled on the drive IC (integrated circuit) side. Currently, the above-mentioned simple matrix type CD panel generally displays up to 16 gradations depending on the performance of the liquid crystal and drive IC.

<Problems to be Solved by the Invention> As described above, the above-mentioned conventional LCD panel is only capable of displaying gradations determined by the performance of the liquid crystal and drive IC, and cannot display multiple gradations beyond that. There is a problem in that it is not suitable as a display device for devices such as personal computers and the like that require display of many gradations.

Therefore, it is an object of the present invention to provide an LCD panel capable of displaying multiple gradations that are higher than the gradations determined by the performance of the liquid crystal and the driver (c).

<Means for Solving the Problems> In order to achieve the above object, the LCD panel of the present invention consists of two liquid crystal layers, each of which is arranged to face each other with a gap between them. A scanning electrode plate in which scanning electrodes are arranged in parallel on one plane; and a signal electrode plate in which a plurality of elongated signal electrodes are arranged in parallel to the scanning electrode plate in a direction perpendicular to the arrangement direction of the scanning electrodes. At the same time, the liquid crystal layer, the scanning electrode plate, and the signal m electrode plate are sandwiched between two polarizing plates, and the signal voltage applied to each liquid crystal layer is changed separately for each liquid crystal layer. It is characterized by displaying the mode.

Effect> In the above-mentioned sliding operation, the signal voltage applied to the two liquid crystal layers is changed separately for each liquid crystal. For example, if a signal voltage that transmits only one half of the light is applied to each liquid crystal, this L
CI) The light passing through the panel is (1/2) x (1/2) =
(1/4), and a 1/4 gradation display can be obtained. Also, if a signal voltage that transmits only one-half of the light is applied to one liquid crystal, and a signal voltage that transmits one-fourth of the light is applied to the other liquid crystal, the light that passes through this LCD panel will be (1/
2) x(1/4)=(1/8), and a 1/8 gradation display is obtained. In this way, it is possible to display more gray scales than in the conventional LCD panel in which one liquid crystal layer is sandwiched between a signal electrode plate and a scanning electrode plate.

<Example> Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

1.2.3 are structural diagrams of a first embodiment, a second embodiment, and a third embodiment of the present invention, respectively.

In FIG. 1, 11, 17 are polarizing plates, 12. ! 6 is a scanning electrode plate, I3 and 15 are liquid crystal layers, and 14 is a signal electrode plate. The two polarizing plates 11.17 have the same polarization direction. Further, the scanning electrode plate 12 has a plurality of elongated electrodes arranged in parallel on the side facing the liquid crystal layer 13 (lower surface), and the scanning electrode plate 16 has a plurality of elongated electrodes arranged in parallel on the side facing the liquid crystal layer 15 (upper surface). The same number of elongated 1llt poles are arranged in parallel in the same direction as the arrangement direction of the signal electrodes. The signal electrode plate 14 has a side (upper surface) facing the liquid crystal layer 13 and a side facing the liquid crystal layer 1.
The same number of elongated electrodes are placed on the side facing 5 (lower surface),
They are arranged in parallel in a direction perpendicular to the arrangement direction of the signal ffl poles. Then, a drive IC (not shown) is connected to the liquid crystal layers 13 and 1.
The signal voltages applied to the terminals 5 can be controlled separately.

Now, the signal voltages applied to the liquid crystal layers t3 and 15 are set to 0/3.1/3.2/3.3/3 for each liquid crystal layer.
It is assumed that settings can be made to obtain four levels of light transmittance. Here, in order to display the brightest gradation, the signal voltage applied to both liquid crystal layers must be adjusted so that the light transmittance is 3.
/3. Then, the polarized light from the polarizing plate 11 passes through the scanning electrode plate I2, the liquid crystal layer 13, the signal electrode plate 14, the liquid crystal layer 15, and the scanning electrode plate 16 as is,
It is displayed brightest without being blocked by the polarizing plate 17.

Next, in order to display the second brightest gradation, the signal voltage applied to either one of the liquid crystal layers 13 or 15 is controlled so that the light transmittance is 3/3, and the signal voltage applied to the other one is controlled so that the light transmittance is 3/3. The signal voltage is controlled so that the light transmittance is 2/3.

Then, the overall light transmittance becomes 6/9, and the polarizing plate 1
The destination that passes through 7 is 6/9 of the light that enters the polarizing plate II Ω=i
The brightness will be . In addition, in order to display an intermediate gradation, the signal voltage applied to both liquid crystal layers must be adjusted so that the light transmittance is 2/3.
Control so that Then, the overall light transmittance becomes 4/9, and the light passing through the polarizing plate 17 has a brightness of 4/9 of the light incident on the polarizing plate 11.

Furthermore, in order to display the darkest gradation, the signal voltage applied to either liquid crystal layer may be controlled so that the light transmittance is 0/3. Then, the overall light transmittance is 0/
9, and all the light incident on the polarizing plate II is blocked by the polarizing plate 17. In this way, depending on the combination of signal voltages applied to the two liquid crystal layers, 0/9.1/9.2/9.
It is possible to display seven gradations of 3/9.4/9.6/9.9/9.

Further, the signal voltage applied to either one of the liquid crystal layers 13.15 is controlled so as to obtain four levels of light transmittance of 0/3.1/3.2/3.3/3, The signal voltage applied to the other one is 0/7.1/7.2/7.3/
If the control is performed so that eight levels of light transmittance can be obtained: 7.4/7.5/7.6/7.7/7, the combination of light transmittances E, J it D, 0/ 21.1/21
,2/2 +,3/21,4/2 L 5/21,6/
2+, 7/21.8/2L 9/21. 10/2
L 12/21.14/21. +5/21, 18/2
It is possible to display 16 gradations of L21/21.

The second embodiment shown in FIG. 2 is an embodiment in which the scanning electrode plate of the first embodiment is replaced with a signal electrode plate, and the signal electrode plate is replaced with a scanning electrode plate. It is possible to display the mode.

In addition, the third embodiment shown in FIG. 3 is different from the first and second embodiments in that it includes one electrode plate between two liquid crystal layers, with electrodes arranged on both the upper and lower surfaces. In contrast, it is equipped with two electrode plates: a scanning electrode plate with r1 poles arranged on the top surface and a signal electrode plate with electrodes arranged on the bottom surface, and is similar to the first and second embodiments described above. Multi-gradation display can be performed.

<Effects of the Invention> As is clear from the above, the LCD panel of this invention has the following effects:
Each liquid crystal layer of two liquid crystal layers arranged to face each other with a gap is connected to a scanning electrode plate having a plurality of elongated scanning electrodes arranged in parallel on one plane, and a scanning electrode plate arranged parallel to the scanning electrode plate. A signal 7 in which a plurality of elongated signal electrodes are arranged in a direction perpendicular to the arrangement direction of the scanning 71X poles.
At the same time, the liquid crystal layer, scanning electrode plate, and signal electrode plate are sandwiched between two polarizing plates, and the signal voltage applied to each liquid crystal layer is varied separately for each liquid crystal layer. Since it is designed to display gradations, it is possible to display multiple gradations that exceed the gradations determined by the performance of the liquid crystal and drive IC. It is extremely useful as a display device.

[Brief explanation of drawings]

Figures i and 2.3 are the first embodiment and the second embodiment of the present invention, respectively.
The structural diagrams of the embodiment and the third embodiment, and FIG. 4.5 are structural diagrams of the conventional example. 11.17.21, 27.31.38...Polarizing plate, t
2, 1.6, 24, 34.37... scanning electrode plate, 13
．． 15, 23, 25, 33.36...liquid crystal layer, 14.2
2.26.32.35・Signal? IX plate.

Claims (1)

[Claims] (1) A scanning electrode plate in which a plurality of elongated scanning electrodes are arranged in parallel on one plane, and a scanning electrode plate for each of two liquid crystal layers arranged to face each other with a gap between them. A plurality of elongated signal electrodes are sandwiched between signal electrode plates arranged in parallel with the direction in which the scanning electrodes are arranged, and the liquid crystal layer, the scanning electrode plate, and the signal electrode plate are sandwiched between two polarizing plates. A liquid crystal display panel characterized in that the signal voltage applied to each of the liquid crystal layers is changed separately for each liquid crystal layer to perform multi-gradation display.