JPH0764118A - Magnetic field optical device and driving method therefor - Google Patents

Abstract

PURPOSE:To display a picture with little temporal change and to reduce power consumption in liquid crystal display. CONSTITUTION:Liquid crystal 23 constituting plural picture elements is sealed between upper and lower substrates 21 and 22, and ferromagnetic substances 24A and 24B controlling the direction of the director of a liquid crystal molecule 23a are arranged for the respective picture elements. The liquid crystal cell 26 is arranged between two polarizing plates 27 and 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field optical device in which the optical properties of liquid crystal are changed by a magnetic field to provide functions such as image display and the like, and a driving method thereof.

[0002]

2. Description of the Related Art A liquid crystal display is known as a display device. As shown in the principle configuration diagrams of FIGS. 6 and 7, a conventional liquid crystal display has electrodes 1 and 2 on the inner surface thereof, respectively, and a liquid crystal is provided between a transparent upper substrate 3 and a lower substrate 4 which are subjected to an alignment treatment. 5, liquid crystal molecules 5 are enclosed by an electric field E generated by applying a voltage between both electrodes 1 and 2.
By controlling the director direction (liquid crystal direction) 6 of a, the light transmission is turned on / off to perform a desired display.

The example shown in the figure is a normally white type liquid crystal display using a twisted nematic type liquid crystal, and the twisted nematic type liquid crystal is arranged so that the director direction 6 of the liquid crystal molecules 5a is twisted by 90 ° between the upper and lower substrates 3 and 4. A liquid crystal cell 7 enclosing 5 is arranged between two polarizing plates 8 and 9 arranged so as to form a crossed Nicols.

In this structure, the light 10 is transmitted when the electric field E is not applied to the liquid crystal cell 7, and when the electric field E is applied, the director direction 6 of the liquid crystal molecules 5a follows the direction of the electric field E as shown in FIG. Is not transmitted, a dark image is displayed on a transparent ground.

[0005]

By the way, the above-mentioned conventional liquid crystal display 11 consumes a large amount of power because of the control by the electric field E, and is suitable for a moving image display such as a receiver which has a rapid temporal change. (Overhead P
It is unsuitable for diversion to so-called still image display, in which there is no temporal change such as projector).

In view of the above points, the present invention provides a magnetic field optical device and a driving method thereof which are capable of reducing power consumption and displaying images with little temporal change.

[0007]

In a magnetic field optical device according to the present invention, liquid crystal 23 constituting a plurality of pixels is enclosed between upper and lower substrates 21 and 22, and a director direction 25 of liquid crystal molecules 23a is controlled in each pixel. Magnetic field generating member 24 [24
A, 24B] are provided.

As the magnetic field generating member 24, for example, a magnetic body for generating a magnetic field by SN magnetization can be used.

A method of driving a magnetic field optical device according to the present invention comprises:
A liquid crystal 2 that constitutes a plurality of pixels between the upper and lower substrates 21 and 22.
3, and a magnetic field generating member 24 [24A, 24
B], the magnetic field generating device 24 is magnetized by an external magnetic field applying means 31 to the magnetic field optical device 29.
The magnetic field H generated by this magnetization controls the director direction 25 of the liquid crystal molecules 23a of each pixel.

As the external magnetic field applying means 31, it is possible to use a magnetic head or a magnetic recording means of a magnetic field modulation overwriting system composed of a laser beam and a magnetic head.

[0011]

In the magnetic field optical device 29 of the present invention, the liquid crystal 23 constituting a plurality of pixels is enclosed between the upper and lower substrates 21 and 22, and the magnetic field generating member for controlling the director direction 25 of the liquid crystal molecules 23a in each pixel. By providing 24, the optical properties of the liquid crystal 23 are controlled by the magnetic field H.

Therefore, it is possible to display an image with low power consumption, and it is possible to display an image such as a still image with little temporal change.

In the method of driving the magnetic field optical device according to the present invention, the magnetic field applying device 31 is provided outside the magnetic field optical device 29.
Since the magnetic field generating member 24 in the inside is magnetized and the director direction 25 of the liquid crystal molecule 23a of each pixel is controlled by the magnetic field H, the still image display which does not change with time becomes possible.

It is possible to erase and redisplay the display by externally magnetizing and erasing the magnetic field generating member 24.

Since the display is possible by holding the magnetic field, it is not necessary to apply a constant electric field as in the prior art. Therefore, power is consumed only when the external magnetic field applying means is energized to write a display, and the power consumption can be reduced.

[0016]

Embodiments of the present invention will be described below with reference to FIGS.

FIGS. 1 and 2 show the principle configuration. In this example, a liquid crystal, for example, a twisted nematic liquid crystal 23 is sealed so as to form a plurality of pixels between transparent upper substrate 21 and lower substrate 22, respectively, and as shown in FIG. Each pixel 2 on the inner surface of the substrate 22
On both sides of the region corresponding to 5 facing each other, for example, the ferromagnetic material 2
4 [24A, 24B] are arranged.

The inner surfaces of the upper substrate 21 and the lower substrate 22 are subjected to an orientation treatment, that is, for example, a rubbing treatment in which the rubbing directions a are orthogonal to each other. Therefore, the twisted nematic liquid crystal 23 between the upper substrate 21 and the lower substrate 22 is sealed so that the director direction 25 of the liquid crystal molecules 23a is twisted. Therefore, the ferromagnetic bodies 24 [24A, 24B] are arranged to face each other in the direction orthogonal to the director direction 25 of the liquid crystal molecules 23a on the lower substrate 22 side.

The liquid crystal cell 26 is arranged between two polarizing plates 27 and 28 which are, for example, crossed Nicols to form a magnetic field optical device 29.

Liquid crystals generally exhibit diamagnetism. When a DC magnetic field H is applied to liquid crystal having magnetic susceptibility anisotropy, magnetic energy density fm is generated.

[0021]

[Equation 1]

When a magnetic field H exceeding a certain strength is applied, the liquid crystal molecules are aligned so that their liquid crystal molecule axes are parallel to the magnetic field direction.

Next, the operation of the magnetic field optical device 29 having the above configuration will be described.

In this device 29, the ferromagnetic materials 24A, 24
If B is demagnetized so that a magnetic field in the surface direction of the lower substrate 22 is not generated, the director direction 25 of the liquid crystal molecules 23a on the lower substrate 22 side is along the rubbing direction as shown in FIGS. Light 30 passes through the polarizing plate 27.

Next, as shown in FIGS. 2 and 4, the pair of ferromagnetic bodies 24A and 24B corresponding to the pixel 25 are magnetized by the magnetic field applying means 31 from the outside so that the pair of ferromagnetic bodies 24A and 24B become the S pole and the N pole, respectively. By doing so, a magnetic field H in a direction orthogonal to the rubbing direction a of the lower substrate 23 is generated by the magnetic flux from the outside. Due to this magnetic field H, liquid crystal molecules 23 on the lower substrate 22 side
The director direction 25 of a changes, that is, the molecular axis is aligned (that is, aligned in the same direction as the liquid crystal molecules 23a on the upper substrate 21 side) so as to be parallel to the magnetic field H direction, and linearly polarized light 30
Is blocked by the polarizing plate 27 and does not pass through.

Therefore, the ferromagnetic material 24 is selectively applied to each pixel.
A desired image can be displayed by magnetizing A and 24B. Then, by demagnetizing the ferromagnetic bodies 24A and 24B to eliminate the magnetic field H, the display can be erased and the next re-display can be performed.

As the magnetic field applying means 31 for magnetizing the ferromagnetic body 24 [24A, 24B], a magnetic head, or a magnetic recording means of a magnetic field modulation overwrite type including a known laser beam and a magnetic head is used. be able to.

Particularly, if the magnetic recording means of the magnetic field modulation overwrite system is used, the minute ferromagnetic material 24 [24A, 2
4B], it is possible to accurately and selectively perform S, N magnetization or demagnetization.

According to the above-mentioned magnetic field optical device 29, the light transmission of each pixel is controlled by the magnetic field, so that it is possible to perform image display with little temporal change, for example, still image display.

Further, since the display can be performed by holding the magnetic field based on the magnetization of the ferromagnetic material 24, power is not always applied, and power consumption can be achieved only by energizing the external magnetic field applying means 31 when writing the display. Good. Therefore, the power consumption of the device 29 can be significantly reduced.

The magnetic field optical device 29 in which a plurality of pixels in the liquid crystal cell 26 are arranged in a matrix is
It can be used as a display device, a so-called liquid crystal display. Since the aperture ratio of each pixel in the current liquid crystal display is about 30%, it is possible to dispose the ferromagnetic material 24 in the remaining 70% region, which is sufficiently applicable as a liquid crystal display.

The magnetic field optical device 29 described above includes a ferromagnetic material 24.
To make it easier to apply a magnetic field from the outside, make the whole thin,
It is possible to have a deformable structure such as a curve.

This magnetic field optical device 29 can be applied as OHP paper by projecting light 30 from the lower substrate 22 side and making it a transmission type.

Further, for example, the polarizing plate 28 on the lower substrate 22 side
A reflection plate is added to the outer surface of the upper substrate 21, and a light-shielding plate having an opening in each pixel is arranged on the outer surface of the upper substrate 21. The light 30 is projected from the polarizing plate 27 side of the upper substrate 21 to determine whether the light 30 is reflected. By controlling, it can be applied as paper such as copy paper. An external magnetic field applying means is provided on the copy machine side.
It can also be applied to a display board such as a whiteboard.

Further, the magnetic field optical device 29 can be applied to window blinds, curtains and the like.

In the above example, as shown in FIG. 3, a pair of ferromagnetic bodies 24A and 24B are arranged on both sides of the lower substrate 22, but the upper substrate 21 side is also rubbed. Also, the lower substrate 22 side is not subjected to rubbing treatment, and as shown in FIG. 5, a pair of ferromagnetic bodies 24 [24A, 24B] are arranged on the left and right sides of the lower substrate 22 for each pixel, and Other ferromagnetic materials 33 [3 paired on both sides
3A, 33B] and the respective ferromagnetic bodies 24 and 33 are arranged.
Liquid crystal molecules 23a by selectively magnetizing and demagnetizing
Can also be configured to control the director direction of the. That is, the ferromagnetic material 24 is demagnetized, the ferromagnetic material 33 is changed to S,
When magnetized N, the liquid crystal molecules 23a on the lower substrate 22 side are oriented as shown by the solid line, light is transmitted, and the ferromagnetic material 24 is moved to S,
When N is magnetized and the ferromagnetic body 33 is demagnetized, the liquid crystal molecules 23a on the lower substrate side are oriented as shown by the chain line and light is not transmitted.

Therefore, when the lower substrate 22 is rubbed to orient the liquid crystal molecules as shown in FIG. 3, the rubbing force of the lower substrate 22 is too strong and the ferromagnetic materials 24A and 24A.
Although the magnetic field H generated by B may make it difficult to control the director direction of the liquid crystal molecules 23a, in the configuration of FIG. 5, there is no such concern, and the director direction of the liquid crystal molecules 23a on the lower substrate 22 side is easy and It can be controlled reliably.

[0038]

According to the magnetic field optical device of the present invention, it is possible to display an image such as a still image with little temporal change, and it is possible to greatly reduce the power consumption during display. Therefore, it can be applied to a display device, a display board, and the like.

When making the whole device thin, O
It can be applied as HP paper and copy paper, and also as window blinds and curtains.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of a magnetic field optical device according to the present invention.

FIG. 2 is an operation explanatory view of the magnetic field optical device of FIG.

FIG. 3 is a plan view of one pixel of the magnetic field optical device according to the present invention.

FIG. 4 is an operation explanatory diagram of one pixel shown in FIG.

FIG. 5 is a plan view of a main part showing another example of the magnetic field optical device according to the present invention.

FIG. 6 is a principle configuration diagram of a conventional liquid crystal display.

FIG. 7 is an operation explanatory diagram of the liquid crystal display of FIG.

[Explanation of symbols]

 1, 2 electrodes 3,21 transparent upper substrate 4,22 transparent lower substrate 5,23 liquid crystal 5a, 23a liquid crystal molecules 24A, 24B, 33A, 33B ferromagnetic material 6,25 director direction 7,26 liquid crystal cell 8, 9, 27 , 28 Polarizing plate 10, 30 Linearly polarized light 11 Liquid crystal display 29 Magnetic field optical device

Claims (2)

[Claims] 1. A magnetic field optical device, characterized in that liquid crystals constituting a plurality of pixels are enclosed between upper and lower substrates, and each pixel is provided with a magnetic field generating member for controlling a director direction of liquid crystal molecules. 2. A magnetic field optical device in which liquid crystals constituting a plurality of pixels are enclosed between upper and lower substrates, and a magnetic field generating member is provided in each pixel, by an external magnetic field applying means.
A method of driving a magnetic field optical device, comprising: magnetizing the magnetic field generating member, and controlling the director direction of the liquid crystal molecules of each pixel by the magnetic field generated by the magnetization.