JPH03219210A - 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 in particular, to a liquid crystal display device using smectic A.
The present invention relates to a thermal writing liquid crystal display device that applies the thermo-electro-optic effect of phase liquid crystal materials, etc.

[Prior art] As a prior art related to a thermal writing liquid crystal display device that applies the thermo-electro-optic effect of a smectic physiognomic liquid crystal material, for example, rSID86 Digest (1986)
Pages 368 to 371 (SID Digest
1986 PP368-371) is known.

The liquid crystal display device according to the prior art uses a liquid crystal element filled with a smectic A-phase liquid crystal material, and on the liquid crystal element,
When a laser beam is focused on a minute spot of about 10 μI and scanned, due to the absorbed heat of the laser beam, if the effective surface size of the liquid crystal element is 40 mm x 40 mm, it will become 2000 x 20
It is possible to write images with a high resolution of 0.00 dots or more. Furthermore, since the liquid crystal element used in this liquid crystal display device has a memory property that retains written images, it is possible to obtain clear images without flicker.

Such a thermal writing liquid crystal display device takes advantage of the above-mentioned characteristics and is used as a central control display device in systems such as various networks and various plants.

[Problems to be Solved by the Invention] As described above, thermal writing liquid crystal display devices are mainly used as control display devices for various systems. Display devices used for these applications need to be able to display both a fixed pattern and sequentially changing information on the same screen.

For this reason, display devices according to the prior art respond to the display of information that changes sequentially by rewriting numerical values, and respond to changes in the status within a system such as a network by changing the display color. was.

Therefore, in the conventional technology, when displaying with a flow,
The problem is that the display is only displayed by changing the display color, and the display is difficult to understand. That is, there are systems, such as water and sewage systems, communications, and electric power networks, that require the direction of flow as information, and the prior art described above cannot display such information in an easy-to-understand manner.

Sequential rewriting of the screen in order to display movement such as the direction of flow is also normally done in other liquid crystal display devices, CRT display devices, etc., but thermal writing liquid crystal display using conventional technology Display devices require several seconds to several tens of seconds to rewrite one screen, making it difficult to display moving images.

Therefore, there is a need for a thermal writing liquid crystal display device that can display images in an easy-to-understand manner so that the actual flow can be recognized.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermal writing liquid crystal display device that can solve the problems of the prior art and visually display various flows in various systems in an easy-to-understand manner.

[Means for Solving the Problems] According to the present invention, the above object is to display a portion representing a flow on a display screen using an intermittent line type such as a broken line or a dashed line, and to display only the flow portion. This is achieved by sequentially rewriting and moving broken parts to display the flow. That is, the purpose is to prepare a plurality of broken line patterns with different broken line parts, store the plurality of broken line patterns in a memory in advance, read out the image data of the broken line patterns one after another, and rewrite them one after another. This is achieved by making

Another object of the present invention is to store a basic pattern expressing a flow in a memory, modify the basic pattern on the display screen based on the coordinates of the starting point and end point of a line that should represent the flow, and This is achieved by rewriting using patterns sequentially.

Further, the above object of the present invention is achieved by using line types that are a combination of a plurality of colors and sequentially rewriting the color combinations.

[Function] The present invention displays corresponding routes on systems such as various processes and networks using intermittent line types such as broken lines and dashed-dotted lines, and rewrites these intermittent lines one after another. By moving the broken line each time it is rewritten, the flow can be expressed. And this rewrite is
Since it is only necessary to rewrite the portion of the route where the movement is to be displayed, and there is no need to rewrite the entire screen, rewriting can be repeated in a short time. With this, the present invention can easily visually display the state of the flow.

[Example] Hereinafter, an example of a liquid crystal display device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a diagram explaining an example of a display screen, FIG. 3 is a diagram showing an example of a pattern showing the flow, and FIG. FIG. 3 is a diagram illustrating an example of coordinate data that provides a broken line pattern. In FIG. 1, 1 is a liquid crystal element, 1a is a liquid crystal layer, lb is a transparent electrode, I
C11f is a glass substrate, 1d is an absorption film, 1e is a reflective plate electrode, 2 is a laser head, 3 is a laser beam, 4 is a horizontal scanning mirror, 5 is a vertical scanning mirror, 6 is a condensing lens, 7 is a light source, 8 is 9 is a condenser lens, 10 is a projection lens, 11 is a screen, 12 is a control section, and 13 is a memory section.

In the embodiment of the present invention shown in FIG. 1, the liquid crystal element 1 is
A mixed liquid crystal material whose main component is a cyanobiphenyl-based smectic A-phase liquid crystal material that has a thermoelectro-optic effect.
A liquid crystal layer 1a with a thickness of 10μ and arranged on both sides thereof,
It comprises a glass substrate IC coated with a transparent electrode 1b made of tin oxide or tin oxide/indium oxide, an absorption film 1d made of chromium oxide, etc., and a glass substrate 1f coated with a reflector electrode 1e made of chromium, aluminum, etc. It is composed of

The liquid crystal element 1 configured in this way has a reflector electrode 1
Image data and the like can be written or erased by irradiating the laser beam 3 from the side e and controlling the voltage applied between the transparent electrode 1b and the reflective plate electrode 1e.

The laser beam 3 includes a semiconductor laser that can be directly modulated such as a GaAs-based, InGaAs-based, or GaAlAs-based laser, a lens that converts the semiconductor laser beam into a parallel beam, and a prism or prism that shapes an elliptical beam into a circular beam. A combination with a cylindrical lens, a combination of a gas laser such as an Ar laser, a He-Ne laser, a He-Cd laser, and an acousto-optic modulation element that turns on/off or modulates the power of the laser beam, or a YAG
It is generated by a laser head 2 that is a combination of a solid-state laser such as a laser and an acousto-optic modulator that turns on, turns off, or modulates the power of the laser beam.

The laser beam 3 output from the laser head 2 is scanned in the horizontal direction by a horizontal scanning mirror 4, and further scanned vertically by a vertical scanning mirror 5. In this way, the laser beam 3 scanned in two directions, horizontal and vertical, is
The light is condensed by a condenser lens 6 and focused on the absorption film ld of the liquid crystal element 1. The absorption film 1d absorbs the laser beam 3 and converts the energy into heat. The liquid crystal layer 1a receiving this heat changes from its initial transparent state to a scattering state due to the thermoelectro-optic effect of the smectic A-phase liquid crystal material, and an image is written thereon.

This scattering state has memorability, and the written image is retained until it is erased.

Note that the liquid crystal element on which the image has been written can be erased in its entirety by applying a voltage of about 100V to 150V between the transparent electrode 1b and the reflection plate electrode IC described above. Furthermore, by applying a voltage of about 30 V between the transparent electrode 1b and the reflection plate electrode IC and irradiating the laser beam, it is possible to erase only the portion irradiated with the laser beam.

In this case, the image shows that the diameter of the focused laser beam 3 is 204 m, and the size of the effective surface of the liquid crystal element 1 is 4 m.
In the case of 0 dragons x 40 m5+, the image has 2000 x 2000 dots, which is a high-definition image.

An image written on the liquid crystal element 1 is obliquely irradiated with light 8 that is projected from a high-intensity light source 7 such as a xenon lamp or a halogen lamp and is condensed by a condenser lens 9. This projected light 8 is reflected by the reflection plate electrode 1e of the liquid crystal element 1, and is transmitted to the screen 1 by the projection lens 10.
It is projected onto 1.

The embodiment of the invention shown in FIG.
A high-definition image of x2000 dots, for example, 2m x 2m
can be projected brightly and clearly onto a large screen.

By the way, as already explained in the prior art section, it takes several seconds to several tens of seconds to erase the entire image and write a new screen, making it difficult to display moving images. be.

Therefore, in the embodiment of the present invention, it is possible to display an image with movement by rewriting only the moving part, that is, the part where the flow should be displayed. in this case,
It is important to separate and overlap the image data of the portion to be rewritten and the image data of the portion not to be rewritten.

The operation according to an embodiment of the present invention will be described below.

In order to perform the above-described operation, the control unit 12 controls the horizontal scanning mirror 4 and the vertical scanning mirror 5 by using respective drive circuits 4a.
, 5a, and also controls the generation of voltages applied to the transparent electrode 1b and the reflection plate electrode 1e in the liquid crystal element 1. Data for performing this control is stored in advance in the memory section 13 connected to the control section 12 as pattern data 13a for expressing the flow.

Next, pre-stored pattern data representing this flow will be explained with reference to FIGS. 2 to 4.

Assume now that a network system is displayed on the screen 14 in advance, as shown in FIG. On this network, station A, station B
There is one station C, which is connected to each other by a communication line. When no communication information is sent over the line,
Each connection line is displayed as a solid line or a stationary broken line to indicate a stopped state.

The image written by the thermoelectro-optic effect of the smectic A-phase liquid crystal material is stably stored, and there is no need to scan the laser beam while displaying the image in the initial state. In this state, from station A to station B
When the transmission of information starts, it becomes necessary to rewrite the corresponding communication line AB on the screen 14 to display the flow of information.

In order for humans to recognize the flow, a uniform pattern such as a solid line cannot be used, but a pattern having non-uniform parts such as a broken line must move. Furthermore, since images have memorability, in order to rewrite patterns to express movement, it is necessary to erase the image and then write a new pattern.

In order to express this flow, patterns shown as broken lines 1 to 5 in FIG. 3 are used. In a monochrome display device, as explained in FIG. 1, the display is made by repeating black and white, but in a color display device, the display can be displayed using dashed lines in different shadings, or by using dashed lines in multiple colors. It can also be displayed.

When using a regular pattern such as the broken line shown in Figure 3, movement can be expressed using a second pattern obtained by moving this basic pattern by half a pitch with respect to one basic pattern broken line 1. However, in order to clearly express the flow direction, it is desirable to use at least three or more patterns.

In the example in Figure 3, the length ratio a:b of black and white is 4:1, and five pattern breaks f are sequentially moved by the length b of white.
il to Wlti15 are shown as rewriting patterns to express the flow.

The flow can be displayed by sequentially and cyclically rewriting the patterns of dashed lines 1 to 5 between station A and station B.
The two white parts move sequentially to positions 15 to 19, and when the pattern of dashed line 1 is redisplayed, it appears to move to position 20, as if the flow was progressing from station A to station B. It looks like The smoothness of the flow can be improved by increasing the number of patterns and reducing the amount of movement of the dashed line by rewriting.
Furthermore, the flow speed can be expressed by changing the rewriting speed.

In this case, the speed of the flow on the screen ll is 2 mm
In the case of a screen, the flow speed is preferably about 0.1 m/s to 5 m/s, and by making the speed of the flow variable, the amount of information to be transmitted can be indicated.

In the thermal writing liquid crystal display device as explained with reference to FIG. 1, in order to sequentially rewrite and display the patterns shown in FIG. The control unit 12 reads the coordinates of the broken line pattern from the memory unit 13, controls the horizontal scanning mirror 4, the vertical scanning mirror 5, and the laser head 2 to write the pattern, and further, Transparent electrode 1b and reflective electrode 1e of liquid crystal display element 1
A control voltage is applied to erase the image.

There are two methods for writing images by scanning the laser beam 3: a raster scanning method that sequentially scans the entire screen like a television, and a vector scanning method that scans a straight or curved electrode between two points like a plotter. Although there is a scanning method, the present invention for displaying a flow uses a vector scanning method in which the portion to be rewritten is limited and only that portion needs to be scanned.

As shown in FIG. 4, the coordinate data set giving each broken line pattern broken tII11 to broken line 5 includes the coordinates of each point on the broken line, the on/off control of the control voltage, and the on/off control of the laser beam.
The configuration is such that the combination of each data with the off control results in data that gives one point. Figure 4 shows broken M
An example of data 1 is shown, and the write data set starts with the coordinates to the start point of the flow, a “0” indicating the control voltage is off, and a “1” that turns on the laser beam. giving. In this state, the laser beam 3 starts scanning from the point at station A to the point at station B, and writes the black portion until it reaches point P. Next, the data set of the point P1 at which the laser beam is turned off is its coordinates P.

, "0" to turn off the control voltage, and "0" to turn off the laser beam. As a result, the laser beam 3 is turned off when it reaches the point P1, and does not write until the next point P2, and this part is marked by the broken line 1.
This will be the white part.

A similar data set is given to each point from point P to point P6, and writing is performed by on/off control of the laser beam 3 in the same manner as described above, and a broken line 1 is drawn between points AB. can be displayed.

When the laser beam 3 reaches point B, it is then controlled to scan towards point A, and from point A again, the next broken line pattern! [2 is written, but before this writing, @ft1l written as described above is erased by scanning from point B to point A. For this reason, a data set for deletion is prepared. This data set contains the coordinates of point B and “1” which turns on the control voltage for erasing.
and "l" which turns on the laser beam 3, so that the laser beam 3 erases the dashed line 1 described above until it reaches point A. When the laser beam reaches point A, the coordinates of point A and "0" which turns off the control voltage are set.
This erasing is completed by setting the data with "O", which turns off the laser beam.

As described above, the first embodiment of the present invention scans back and forth between points AB with the laser beam 3 using the data set of the broken line patterns broken line 1 to broken line 5, and sequentially repeats writing and erasing of each broken line pattern. Accordingly, the flow between points AB can be displayed.

Note that the control voltage during the above-mentioned erasing operation is about 30 V, and when the liquid crystal element 1 is scanned with a laser beam while this control voltage is applied, the laser beam is Only the irradiated area will be erased.

According to the first embodiment of the present invention described above, all the coordinate data for displaying the flow is stored in advance in the memory 13, so that it can be displayed on the screen in a short processing time and without causing malfunction. Flow conditions such as flow direction and speed can be displayed.

FIG. 5 is a diagram illustrating a method of writing a pattern representing a flow according to a second embodiment of the present invention. In this second embodiment of the present invention, a pattern representing a flow is written using relative coordinates.

As shown in FIG. 5, the basic pattern is a combination of a black part of length C and a white part of length d, and the length ratio of black to white is 4:1. The coordinate data set of relative coordinates in this example is (0,0,1), (q+tot
o), (qa, 0.1), and the combination data of each coordinate set is based on the first coordinate data, the second control voltage on/off data, and the third laser beam on/off data. It is configured.

As in the case of the first embodiment of the present invention described above, the operation of the second embodiment of the present invention will be described assuming that the line from station A to station B is in operation.

In this case, the coordinates of station A and station B are set independently of the flow pattern. Therefore, when writing a broken line from station A to station B, the aforementioned basic pattern of total length c0d is sequentially written while changing the coordinate data of the basic pattern. , if dashed line 1'' is formed in this way, the basic pattern shown as m=4 that comes at the end will not be completed and will be terminated at the coordinates of station B. Dashed line pattern 2'' will be the white line of the basic pattern. It can be formed by shifting the initial basic pattern by a portion length d. Furthermore, for the broken line pattern 3'', the first basic pattern can be shifted by a length of 2d, but the black is placed on the station A side by a length of 2d.
It can be formed by adding only -d. In addition, the broken line 4' has a length of d by adding a black part of length 3d-d first.
Similarly, for the dashed line 5', first add a black part of length 4d-d, then continue the basic pattern after the white part of length d. It can be formed by going through the steps.

The second embodiment of the present invention uses five broken line patterns from broken line 1' to broken line 5' formed as described above.
The flow can be expressed in the same way as in the first embodiment of the present invention.

This method of generating a dashed line pattern using relative coordinates allows you to automatically create a specific dashed line pattern by preparing one basic pattern and simply providing data for the start and end points when editing image data on the screen. can be generated and used to display the flow.

In this case, the data of each broken line pattern that is automatically generated during editing is stored in memory, and when actually displaying the flow, the data is read out from the memory and written to the liquid crystal display element. Erasing may be repeated. Further, when actually displaying the flow, writing and erasing on the liquid crystal display element may be repeatedly performed while generating a broken line butter from the input data of the start point and end point.

In both the first and second embodiments of the present invention described above, in order to generate a dashed line pattern expressing a flow,
Three pieces of data are used: coordinate data for turning on and off the laser beam, data for turning on and off the laser beam, and data for turning on and off the control voltage. However, the present invention can express the flow without using such coordinate data.

FIG. 6 is a diagram illustrating the operation of the third embodiment of the present invention. This third embodiment of the present invention allows flow to be expressed without using coordinate data.

Now, assuming that the line from station A to station B is in operation, its operation will be explained.

The laser beam is controlled to continue scanning while reciprocating between station A and station B at a constant speed. During this time, a pulse voltage at regular intervals is applied as a control voltage. The voltage value of this pulse voltage is a voltage higher than the threshold value of the thermoelectro-optic effect of the smectic A-phase liquid crystal material, and changes alternately between positive and negative.

The combination of the moving irradiation of the laser beam and the pulse voltage is set as shown in FIG.

That is, on the outward journey, the laser beam continues to be irradiated from station A to station B at a constant speed. Assuming that the distance between station A and station B is D and the laser beam is reciprocated in a time of 2, the moving speed of the laser beam is D/l. The pulse interval of the control voltage is t
e. If the pulse width is tf, during the time tf the pulse voltage is applied, erasing is performed instead of writing, so this part becomes white, and the other parts are in the written state due to laser beam irradiation. The color becomes black. Therefore,
On the screen, a constant black and white pattern is repeated with an interval e=te/l-D, and the length of the white part is:
f=t f/l −D.

Then, on the return trip, the pulse position of the control voltage is moved so that each white portion moves by a length f toward the station B side. That is, the relationship between the distance D between station A and station B, the pulse interval 1iie, and the pulse width f is as follows.
D=me+f/2 (where m=integer). f/2f is necessary in order to move the white part by exactly the length f when the laser beam reciprocates.

In the third embodiment of the present invention, it is not necessary to apply an erase control voltage after writing the broken line 10 and before writing the broken line M[11.

In the third embodiment of the present invention described above, the control voltage to be applied is changed to alternating current with two pulses, but alternating current voltage may be applied as one pulse, and instead of the pulsed voltage, Sine wave voltage that changes positive and negative, triangular voltage,
A sawtooth voltage may also be applied.

Although the embodiments of the present invention described above apply the present invention to a monochrome liquid crystal display device, the present invention can be similarly applied to a color liquid crystal display device.

[Effects of the Invention] As explained above, according to the present invention, it is possible to visually display the system status, flow direction, speed, amount, etc. to the operator on a large screen display for system control. , it becomes possible to display the status of the entire system in an easy-to-understand manner.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the first embodiment of the present invention, FIG. 2 is a diagram explaining an example of a display screen, FIG. 3 is a diagram showing an example of a pattern showing the flow, and FIG. FIG. 5 is a diagram illustrating an example of coordinate data that provides a broken line pattern. FIG. 5 is a diagram illustrating a method for writing a pattern representing a flow according to the second embodiment of the present invention. FIG. It is a figure explaining operation of an example. 1...Liquid crystal element, 1a...Liquid crystal layer, 1
b...Transparent electrode, lc, If...Glass substrate, 1d...Absorption film, le...Reflector electrode, 2... Laser head, 3...
・Laser beam, 4...Horizontal scanning mirror, 5.
... Vertical scanning mirror, 6 ... Condensing lens, 7 ... Light source, 8 ... Projection light, 9 ...
...Condenser lens, 1o...Projection lens, 11...Screen, 12...Control unit, 13...Memory unit. Figure 1 Water, -'12-fl pay'' L mirror 13: / Mori 7p Figure 4 Figure V 〇 turn to the basics Relative paddle 0 Station A Figure 2 , ) q+ , q2 Stain B

Claims (1)

[Claims] 1. In a liquid crystal display device in which an image is written by irradiating a laser beam onto a liquid crystal element sealed with a liquid crystal material having a thermoelectro-optical effect, the movement can be realized by sequentially rewriting only the moving parts. A liquid crystal display device characterized by displaying an image. 2. The liquid crystal display device according to claim 1, wherein rewriting only the moving portion is performed by scanning only the portion to be rewritten with a laser beam. 3. The liquid crystal display according to claim 1 or 2, wherein a plurality of patterns for displaying movements necessary for rewriting only the moving part are stored in advance in a memory section. Device. 4. In a liquid crystal display device in which an image is written by irradiating a laser beam onto a liquid crystal element sealed with a liquid crystal material having a thermoelectro-optic effect, the portion displaying movement is repeatedly scanned with a laser beam at a constant speed, and A liquid crystal display device characterized in that it displays a moving image by controlling a control voltage applied to a liquid crystal display element and rewriting this portion. 5. The liquid crystal display device according to claim 1, wherein the moving image is an image displaying a flow. 6. By giving a dashed line pattern using relative coordinates,
Claim 5, characterized in that a flow is displayed.
The liquid crystal display device described in Section 1. 7. In a liquid crystal display device in which an image is written by irradiating a laser beam onto a liquid crystal element sealed with a liquid crystal substance having a thermoelectro-optic effect, the portion displaying movement is repeatedly scanned at a constant speed by a laser beam, and , a liquid crystal that displays an image showing a flow by applying a control voltage in the form of a pulse train, a sine wave, a triangular wave, or a sawtooth wave whose voltage value alternately changes to the liquid crystal display element and rewriting this part. Display device.