JPS62222218A - liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain the titled element having an improved display quality, and to raise a practical use of the whole of the liquid crystal display by making a direction of orientation treatment to an acute angle capable of operating without mixing a chiral substance to the liquid crystal. CONSTITUTION:An orientation treatment is effected to the orientation film mounted on the inner surface of a glass substrate 1 in the prescribed direction 1f of the orientation. Similarly, the orientation treatment is effected to the orientation film mounted on the back surface of the glass substrate 2 in the prescribed direction 2f of the orientation. The prescribed orientation treatment is effected so as to make the angle of between the orientation directions 1f and 2f of the substrates 1 and 2 to 60-85 deg.. Polarizing plates are sticked on the outer surfaces of the substrates 1 and 2 respectively. The angle of between the direction 1p of the polarizing axis of the polarizing plate sticked on the front surface side of the substrate 1 and the direction 2p of that sticked on the back surface side of the substrate 2 is made to 105-150 deg.. The gap (d) of between the facing substrates 1, 2 is adjusted so as to satisfy the product value of DELTAnd shown by the formula wherein DELTAn is a value of anisotropy of the refractive index of the liquid crystal enclosed in the gap and (d) is a distance of the gap. The chiral substance is not added to the liquid crystal.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a liquid crystal display element widely used as a display device for watches, calculators, and other devices, and particularly relates to a method for forming a TN (Rice 1 to Nematic) liquid crystal element. This gives the liquid crystal element excellent visibility. K. Prior Art The structure of a conventional TN liquid crystal element of this type is, for example, as shown in a front view in FIG.
The direction F of the light distribution treatment by rubbing etc. applied to the glass substrate 12 and the direction B of the similar alignment treatment applied to the glass substrate 12 on the back side are made to have an angle of 90 degrees to each other. A polarizing plate is attached to the closing plate 11.12 so that the polarization axes PF and PB are in the same direction as the light distribution treatment applied to each substrate. By mixing a minute amount of chiral material into the liquid crystal material sealed in the gap, the directionality of the liquid crystal material is stabilized and the so-called reverse twist phenomenon, in which something is twisted in the opposite direction, is prevented. It is something. [Problems to be Solved by the Invention] However, the inclusion of the chiral substance described above has an l711 effect that increases the operating voltage threshold of the liquid crystal substance, impairing the operational responsiveness of the liquid crystal display element. In addition to causing problems, the mixing of foreign substances into the liquid crystal material also deteriorates basic performance such as anisotropy with respect to light, and display performance such as display contrast also deteriorates significantly.
As a result, a problem also arises in that the quality of the display is severely degraded. The fourth graph shows the relationship between drive voltage and transmittance of this conventional liquid crystal display element.
For example, to explain the characteristics when the observation angle θ = 0 degrees, that is, when viewed from the front, about 3 volts are required for the liquid crystal display element to respond completely,
Other observation angles θ are small! At a voltage of 2 volts, the contrast is low only when viewed from the front, making it unsuitable for practical use, and for this reason, a high driving voltage must be applied. Means for Solving Problem K] As a specific means for solving the problems of the conventional TN liquid crystal display element described above, the present invention provides glass substrates with transparent electrodes provided on their opposing inner surfaces. In a liquid crystal display element consisting of a liquid crystal substance sealed between the glass substrates and polarizing plates provided on the outer surfaces of the glass substrates, the direction of the alignment treatment applied to one of the glass substrates and the direction of the other glass substrates are determined. The angle formed with the direction of the orientation treatment applied to one side is from 60 degrees to 8 degrees.
5 degrees, the angle formed by the transmission axis of each of the polarizing plates is from 105 degrees to 150 degrees, and the refractive index anisotropy value Δn of the liquid crystal material and the gap dimension d between the opposing glass substrates. By providing a liquid crystal display element characterized in that the product value is set to 0.4≦Δnd<Q, 3, and the liquid crystal substance is further characterized in that a chiral substance is not heated, the above-mentioned conventional problems can be solved. It is something to be solved. K Embodiment Next, the present invention will be described in detail based on an embodiment shown in the drawings. What is indicated by the reference numeral 1 in the front view of FIG. 1 is a glass substrate on the front side, and an alignment film is provided on the inner surface of the glass substrate 1, and the alignment film is subjected to a predetermined alignment treatment by a method such as rubbing. The orientation process is performed in the direction 1f. Similarly, an alignment film is provided on the inner surface of the glass substrate 2 on the back side, and an alignment process is performed in the alignment direction 2f.
At this time, the orientation treatments performed are different from conventional orientation treatments in that the angles formed by the directions 1' and 2f of the orientation treatments performed on the respective glass substrates 1, 2 are from 60 degrees to 85 degrees. In addition, as in the conventional case, a polarizing plate is attached to the outer surface of each of the substrates 1 and 2 of IYj, but the attachment of the polarization axis of this polarizing plate is The angle is completely different from that used in the conventional example, and the glass substrate 1 on the front side is attached to the glass substrate 2 on the back side.
Pasting is performed based on the direction 2f of the orientation treatment performed on the glass substrate 1 on the front side.
Paste based on f

[Push is performed.] At this time, the direction 1p of the polarization axis of the polarizing plate attached to the glass substrate 1 on the front side and the glass substrate 2 on the back side
The accuracy of the polarization axis 2p of the polarizing plate attached to the substrate is set to be 105 degrees to 150 degrees, but this obtuse angle is made to sandwich the acute angle formed by the alignment treatment performed on each of the glass substrates 1.2. , and the front glass substrate 1
direction 1f of orientation treatment, direction 2p of the polarization axis of the polarizing plate attached to the glass substrate 2 on the back side, direction 2f of orientation treatment of the glass substrate 2 on the back side, and glass substrate 1 on the back side. The direction of the polarization axis of the polarizing plate attached to the
The angle formed by each p is set to be from 10 degrees to 45 degrees. Furthermore, according to the present invention, the glass substrates 1.2 facing each other as described above have a refractive index anisotropy value Δn of the liquid crystal material sealed therebetween and the glass substrates 1.2. The product value Δnd multiplied by the gap d of 1.2 is 0
, 4≦And≦0.8, 1) is set as the distance between the opposing glass substrates, and no chiral substance is mixed in the liquid crystal material 11a. By configuring the TN liquid crystal display element in this way, the second
As shown in the figure, the threshold voltage is lowered so that the driving voltage for all observation angles θ is approximately 2 volts, and the polarizing plate is attached at an acute angle in the left and right directions of the display as described above. This allows for a wide viewing angle in that direction. [Effects of the Invention] As explained in Section 2 below, according to the present invention, the direction of the alignment treatment is set at an acute angle that can be adjusted without mixing a chiral substance into the liquid crystal material, and the direction in which the polarizing plate is attached is adjusted to the direction of the alignment treatment. By eliminating the need for the inclusion of the chiral substance, it is suitable for eliminating unnecessary upper bounds on the drive voltage due to the increase in threshold value, decrease in contrast, and narrowing of the observation angle, etc. that occur in conventional devices. This has the excellent effect of solving all the problems, increasing the practicality of this type of liquid crystal display as a whole, and further improving the display quality.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the direction of alignment treatment and polarizing plate attachment in one embodiment of a liquid crystal display element according to the present invention, and FIG. 2 shows the relationship between driving voltage and transmittance of a liquid crystal display element according to this embodiment. Graphs are shown for each observed color. Figure 3 is an explanatory diagram that does not show the direction of alignment treatment and polarization temporary pasting in a conventional example. Figure 4 is the relationship between drive voltage and transmittance of a conventional liquid crystal display element. This is a graph showing the dimensions of each observed color. 1.2...Glass substrates 1f, 2r...Orientation treatment direction lp, 2p...Polarization direction of polarizing plate 0...Observation angle 1st! ! l Figure 2 E 3rd t! 1 Figure 4 Voltage

Claims (1)

[Scope of Claims] Consisting of glass substrates each having a transparent electrode on their opposing inner surfaces, a liquid crystal substance sealed between the glass substrates, and a polarizing plate provided on the outer surface of each of the glass substrates. In the liquid crystal display element, the angle between the direction of the alignment treatment applied to one of the glass substrates and the direction of the alignment treatment applied to the other glass substrate is in the range of 60 degrees to 85 degrees, and The angle formed by the transmission axis is 105 degrees to 150 degrees, and the product value of the refractive index anisotropy value Δn of the liquid crystal material and the gap size d between the opposing glass substrates is 0.4≦Δnd≦0.8. A liquid crystal display element further characterized in that a chiral substance is not mixed in the liquid crystal substance.