JPS63184724A - liquid crystal display device - 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 [Field of Industrial Application] The present invention relates to a liquid crystal display device, and particularly to a liquid crystal display device with a multilayer structure.

[Conventional technology]

Conventionally, in cases where the display area is relatively small, such as on a wristwatch, multiple liquid crystal display elements are arranged in a layered manner and the image of each element can be switched for the purpose of multifunctionalizing the displayed content or improving fashionability. Alternatively, a liquid crystal display device with a multilayer structure that displays images in an overlapping manner has been proposed (1983-
103788).

[Problem that the invention seeks to solve]

Conventional liquid crystal display devices having a multi-layer (for example, two-layer) structure have had few display contents and have been driven statically or at a low time-division drive of about 1/3 duty, so there have been no particular problems.

However, with the recent demand for an increase in display information, when high-time division driving is performed, the operating point of the upper and lower liquid crystal display elements decreases, resulting in a poor balance between the top and bottom display contrasts. occurred.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device with a multilayer structure in which the display contrast of the multilayers is well-balanced.

[Means for solving problems]

The above problem can be solved by providing a drive circuit equipped with means for adjusting the drive voltage applied to each liquid crystal display element in each layer.

[Effect]

For example, in a two-layer liquid crystal display device, the display contrast can be improved by setting the driving voltage of the lower liquid crystal display element, which displays darker than the upper part at the same driving voltage, to be lower than that of the upper part. It is possible to match.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention.

1 is an upper liquid crystal display element, 2 is a lower liquid crystal display element,
3.4 is an upper polarizing plate of each liquid crystal display element, 5 is a lower polarizing plate of the lower liquid crystal display element, 6 is a reflecting plate, and T is a glass substrate. The periphery of each glass substrate is sealed with a sealing material 8, and a lower electrode 11 is disposed opposite to the upper electrode 9 and the liquid crystal 10t via the upper electrode 9 and the liquid crystal 10t.

In such a two-layer liquid crystal panel, since the display on the lower liquid crystal display element 2 is viewed through the polarizing plate attached to the upper liquid crystal display element 1, the color tone becomes dark. On the other hand, the display on the upper liquid crystal display element 1 becomes thinner because the distance to the reflector 6 attached to the lower surface of the lower liquid crystal display element 2 becomes longer.

For this reason, the drive circuit 12 of this embodiment connects two variable resistors VR1 and VRZ in parallel to the power supply E, and divides the power supply voltage into voltages v, l and v2, respectively (Vt
>Vz) was applied to the upper liquid crystal display element 1 and the lower liquid crystal display element 2. vI+v2 can be adjusted independently using variable resistors VR1 and VB2.

FIG. 2 shows the relationship between the drive voltage and the control and last ratios of the two-liquid high display element, and as mentioned above, the drive voltage v1 and v
2, the contrast ratio of the upper liquid crystal display element 1 represented by the solid line I can be made to match the contrast ratio of the lower liquid crystal display element 2 represented by the broken line 1.

〔Effect of the invention〕

According to the present invention, in a multilayer liquid crystal display device,
It becomes possible to make the contrast of the liquid crystal display elements of each layer the same, and display quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing driving voltage-contrast ratio characteristics. 1... Upper liquid crystal display device, 2... Lower liquid crystal display device, 12... Society drive circuit, VRl. VB2・φ・・Variable resistor.

Claims (1)

[Claims] 1. A liquid crystal display device having a multilayer structure in which liquid crystal display elements are stacked in multiple layers, characterized in that a drive circuit is provided with means for adjusting a drive voltage applied to each layer of liquid crystal display elements.