JPH02116826A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To surely protect the secrecy of liquid crystal cell at need by providing a pair of front and rear polarizers which are disposed to both the front and rear surfaces of a liquid crystal cell and constitute the device body together with a liquid crystal and mounting the front side polarizer attachably and detachably to the device body. CONSTITUTION:The two polarizers 19, 20 constitute the device body 21 together with the liquid crystal cell 11, etc., and the front side polarizer 20 is mounted attachably and detachably by an insertion operation between guide parts 22 and 22 formed to a cover so that only the user can view the display information. The user removes the front side polarizer 20 from between the guide parts 22 and 22 and bring the polarizer to just before the user's eyes if the user does not want the display information to be seen by other persons. Then, only the user who uses this polarizer 20 can view the display information. The secrecy of the display information is thus preserved. The user is able to confidentially see the display information without having polarizing spectacles; in addition, the possibility of the loss, etc., of the polarizer is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a liquid crystal display device applied to a display section of office automation equipment or various industrial equipment such as a word processor or a burner computer.

<Prior art: Title a> Generally, when you want to convey some kind of information only to a specific person,
For example, if you want to communicate business communications, confidential information, or display information on a personal computer to only a specific person, it is necessary to display and communicate that information only to those limited people. be. However, when handling confidential information on a personal computer, for example, there is a risk that the displayed information will be visible to others. In this case, the user of the personal computer must secure an operation area where no one else is present in order to protect the confidentiality of the displayed information, and the user must always be aware of the gaze of others while operating the computer. There is.

Under these circumstances, the system shown in Japanese Utility Model Publication No. 53-45583 has already been devised. In this device, a polarizer is provided on the rear side of a translucent liquid crystal cell in which a liquid crystal material having positive dielectric anisotropy is filled in a twisted nematic structure between a pair of translucent substrates, and the main body of the device is constructed. There is a type of polarized glasses in which a user wears a polarizer that rotates within the liquid crystal material by applying a voltage between a pair of transparent electrodes in the liquid crystal cell and passes only the light that passes forward. That is, only a user wearing polarized glasses in front of the device main body can view the displayed information.

However, since the above configuration requires the user to wear polarized glasses, the displayed information cannot be seen unless the user wears them. You will also not be able to see the displayed information.

<Object of the Invention> The present invention has been made in order to solve the above-mentioned problems of the conventional device, and an object thereof is to provide a simple liquid crystal display device that can reliably protect the confidentiality of displayed information when necessary.

<Structure and Effects of the Invention> A liquid crystal display device according to the present invention has a twisted nematic structure filled with a liquid crystal material having positive dielectric anisotropy between a pair of transparent substrates, and A mounting body is constituted by a liquid crystal cell in which the orientation of a liquid crystal substance is changed by applying a voltage between a pair of transparent electrodes provided on opposing surfaces, and the liquid crystal cells arranged on both the front and rear surfaces of this liquid crystal cell. The device includes a pair of front and rear polarizers, and the front polarizer is detachably attached to the main body of the device.

According to this invention, the front polarizer is removable from the main body of the device, so that by using this polarizer, the user can secretly view the displayed information without the need for conventional polarized glasses. In addition, the fear of losing the polarizer is also eliminated.

<Explanation of Examples> Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an example in which a liquid crystal display device according to the present invention is applied to a personal φ computer.

In the figure, 1 is a keyboard board on which keys 2 are arranged, 3 is a part of a cover rotatably supported on the keyboard board 1, and a liquid crystal display device 4 is disposed thereon.

The structure of this liquid crystal display device 4 will be explained with reference to FIG. 2 and FIGS. 3a and 3b.

In the figure, 11 is a liquid crystal cell, which has a pair of glass substrates 13.14 facing each other with a spacer 12 in between, and a positive dielectric anisotropy filled between the two substrates 13.14. It consists of a nematic phase liquid crystal material 15 and a pair of transparent electrodes 16.17 provided on each opposing surface of the substrates 13.14, one of which is formed as an individual electrode in a dot-like pattern. Reference numeral 18 denotes a reflecting plate arranged on the rear side of the glass substrate 14.

The liquid crystal substance 15 having positive dielectric anisotropy is, for example, bis-(4-n-octyloxybenzal)-2-
40 parts by weight of chlorophenylenediamine, 50 parts by weight of P-methylbenzal-p-n-butylaniline, and p-
It is obtained by blending 10 parts by weight of cyanobenzal-p-n-butylakoline, and when a sufficiently strong electric field is applied to this liquid crystal material 15, the molecules of this liquid crystal material 15 lose their previous orientation. It has the property that the molecules are arranged parallel to each other along the direction of the electric field.

One of the glass substrates 13 and 14 mentioned above
is polished along the solid line Xa in FIG. 3, and the other glass substrate 13 is polished along the dotted line Ya forming a desired angle, for example, 90 degrees, with respect to the solid line Xa. For this reason, the liquid crystal 15 has a twisted nematic structure and is filled in the liquid crystal cell 11, and this nematic liquid crystal has a characteristic that the liquid crystal molecules near the polished surface are cured and arranged in the direction in which only the surface is polished. has.

19 is the rear side of the liquid crystal cell 11, that is, the glass substrate 1
A polarizer placed on the 4 side, this polarizer 19 is indicated by the arrow xb
It is configured to pass light with a plane of polarization in the force direction.

The xb force direction and the Xa force direction are set in the same direction. 2
0 is a polarizer disposed on the front side of the liquid crystal cell 11, that is, on the front side of the glass substrate 13, and is configured to pass light having a polarization plane in the direction of arrow Yb. Both polarizers 1
9.20 is the device main body 21 along with the liquid crystal cell 11 etc.
The front polarizer zO is removably attached by inserting it between the guide parts 22 and 22 (Fig. 1) formed on the cover 3 so that only the user can see the displayed information. ing.

The Yb direction in the polarizer 20 is set along the arrow Ya force direction of the glass substrate 13.

23 is a DC power supply, 24 is a power switch, and 25 is a power supply voltage applied to transparent electrodes 16 and 17 by opening the switch 24.
This is a drive circuit that applies voltage between the two.

Next, the operation of the above configuration will be explained.

Now, close the power switch 24 and apply a DC voltage to the individual transparent electrodes 16 and 17 via the drive circuit 25.
When applied between the individual transparent electrode 16 and the transparent electrode 17
A change occurs in the liquid crystal 15 between the
The effect of rotating the plane of polarization by 90° disappears. That is, the twisted nematic structure of the liquid crystal 15 in this portion disappears. Here, the individual transparent electrode 1 to which a voltage is applied
The liquid crystal 15 in all parts other than the part corresponding to 6 has a 90' twisted nematic structure.

Therefore, among the light from the reflection plate 18, the plane-polarized light La that has passed through the polarizer 19 travels straight in the portion corresponding to the individual transparent electrode 16, and the plane of polarization is 90° in all other portions.
It rotates and reaches the polarizer 20.

By the way, since the light Lc passing through the glass substrate 13 includes both the light traveling straight through the liquid crystal cell 11 and the light passing through the liquid crystal cell 11 after being rotated by 90', the light Lc passing through the glass substrate 13 It is not possible to visually determine what information is being displayed.

Of the light Lc that has reached the polarizer 20, only the light Lb that vibrates only in the direction of the arrow Yb passes through the polarizer 20.

That is, only the light that has rotated by 90 degrees and passed between the liquid crystals 15 having a twisted nematic structure passes through the polarizer 20 in all parts other than the parts corresponding to the individual transparent electrodes 16 to which a voltage is applied.

Therefore, by inserting the front polarizer 20 between the guide parts 22 and 22 shown in FIG. 1 and attaching it to the main body 21 of the device as shown in FIG. can be visually recognized.

If you do not want others to see the displayed information, remove the front polarizer 20 from between the guide parts 22 and 22 and bring it in front of the user's eyes as shown in Figure 3b. Only the user using the device 20 can view the displayed information, and can protect the confidentiality of the displayed information.

In particular, since the polarizer 20 is configured to be detachable from the device body 21, it is possible to protect the confidentiality of displayed information by using the polarizer 20 at any time, even in the absence of conventional polarized glasses. Information becomes easier to handle. In addition, the polarizer 20 used for the above-mentioned secret protection is attached to the device main body 21.
By attaching it to the camera, the fear of losing it is also eliminated.

By the way, the structure for attaching and detaching the polarizer 20 to and from the device main body 21 is merely an example shown schematically, and various other structures may be adopted as appropriate.

Further, in the above embodiments, the liquid crystal cell 11 is of a reflective type, but a transmissive type is also applicable.

Furthermore, although the above example is applied to a personal computer, it can also be applied to other office automation equipment such as a word processor, and furthermore, it can be applied to the PIN number display section of an automatic teller machine. Of course, it can also be applied.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing an example in which the liquid crystal display device according to the present invention is applied to a personal computer, FIG. 2 is an exploded perspective view showing the configuration of the liquid crystal display device in FIG. 1, FIG. FIG. 3b is a sectional view showing an example of the use of the same liquid crystal display device. 11...Liquid crystal cell, 13.14...Substrate, 15...
・Liquid crystal substance, 16.17...Transparent electrode, 19.20・
...Polarizer, 21...device main body. 1st Figure 20: 1st photon

Claims (1)

[Claims] (1) A liquid crystal material having a positive dielectric anisotropy is filled between a pair of transparent substrates in a twisted nematic structure, and is spread between a pair of transparent electrodes provided on each opposing surface of the above substrates. a liquid crystal cell in which the orientation of the liquid crystal substance changes upon application of a voltage; and a pair of front and rear polarizers disposed on both the front and rear surfaces of the liquid crystal cell and forming a device main body together with the liquid crystal cell; A liquid crystal display device characterized in that a polarizer is removably attached to the main body of the device.