JPS60200331A - Coordinate input device - Google Patents

Abstract

PURPOSE:To obtain a coordinate input device which unifies a coordinate input part and a display part with no use of exclusive paper and enables a user to observe the display on a writing surface, by using the upper and lower parts of a liquid crystal surface for a display part and an input tablet respectively. CONSTITUTION:An input part 1 contains 3,200 liquid crystal molecules total 3,200 (40 rows and 80 columns) and divides these molecules into 80 blocks every 40 pieces. These 80 blocks are driven simultaneously. It is possible only at a position in direction Y where vertical 40 molecules defined as a block to detect an area to which the light is irradiated. Therefore, an infrared light emitting source 11 is provided above a photodetecting part 10 of a writing tool 2 in order to identify each block. Then the emitted infrared rays are received by an auxiliary discriminating photodetecting part 9. The part 9 has a rectangular parallelepiped shape containing holes 12. The photodetecting sensors 13 are buried into holes 12 respectively, and these sensors 13 are put in parallel to each other with the same pitch as the liquid crystal molecules. The sensor 13 outputs an output larger than a fixed level only in case the tool 2 is set on the line of the hole 12. Thus it is possible to identify a position in the direction X where the tool 2 exists.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a coordinate input device used in an online character recognition device.

(Background Art) Conventional online character recognition devices write characters on a tablet, and display the results of recognizing strokes input by handwriting on a separately provided CRT or on a display attached to the device. It was displayed.

For this reason, the writing surface and the display surface are different, and it is necessary to move the line of sight to check whether the writing result has been entered correctly, which not only slows down the input speed but also causes greater ergonomic fatigue. There were equally shortcomings.

Furthermore, when a person writes a sentence, he or she usually looks at the content of the sentence that has been written up to that point and works out the next sentence. In the case of writers, some people have the ability to create logical sentences even when dictating them, but it is well known that it is difficult for ordinary people to understand words spoken spontaneously when read as written text. In order to prevent this and create sentences that are logically consistent, it is necessary to
I write the next sentence while looking at about three lines. When inputting text in this way, it is necessary to be able to see the text that has been input up to that point near where the writing instrument is.

In the case of online character recognition devices, when inputting, there are some that require writing on a specific paper, but it is also necessary to check on the display whether or not the input is being entered (recognized) as written on the paper. The normality of recognition and the logicality of sentences must be checked separately, and from this point of view, the difference between the writing surface and the display surface significantly worsens the workability of text input.

(Problems to be solved by the invention) An object of the present invention is to provide a coordinate input device that allows input to an online character recognition device to be performed on a tablet in the same way as writing on paper, and that does not require special paper. Our goal is to provide a coordinate input device that integrates the coordinate input section and display section so that the display can also be seen on the value writing surface.The feature is that it uses the display function and shutter function of the liquid crystal element. The reason is that the upper part of the liquid crystal surface is used for display purposes, and the lower part is used for input tablet use.

That is, the lower part of the liquid crystal surface is a tablet that uses a shutter function, and the input function is achieved by sensing the reflection of incident external light with a light receiving section provided at the tip of the writing instrument.

Furthermore, by using the upper part as a display surface to display the input status, the results can be displayed close to the writing instrument, and the input section and display section can be realized by an integrated liquid crystal element.

(Structure and operation of the invention) First, the operating principle of a liquid crystal display element, which is the basis of the present invention, will be explained. It is well known that a liquid crystal display element can be said to be an electric shutter for light, and when a voltage is applied, it blocks the passage of light, and when no voltage is applied, it allows light to pass through.

The configuration is as shown in FIG. 1, in which the main body of the liquid crystal display element 106 is
It is sandwiched between two polarizing plates 102 and 110, and the polarizing axes of the upper and lower polarizing plates 102 and 110 are arranged at right angles to each other. As shown in FIG. 1(a), when no voltage is applied between the transparent electrodes 104 and 108, the liquid crystal molecules are oriented in a 9-node twist, so the light rotates by 9σ, and as a result, the light passes through. Here, transparent electrode 104.1
When a voltage is applied between 08 and 08, the liquid crystal molecules align in a fixed direction as shown in Figure 1(b), so the light does not rotate, and the polarizing axes of the polarizing plates are at right angles to each other, so the light is blocked. becomes. The liquid crystal display is structured so that a reflective plate is placed in close contact with the lower polarizing plate to reflect the light that enters from above.When displaying characters, etc., voltage is applied only to the part you want to display. The structure is such that the light does not reflect and the letters appear black.

Next, conventionally, liquid crystal display elements cannot be used for applications other than display elements due to the inability to reduce the dot pitch and the slow reversal speed of liquid crystal molecules. 1m5e in one cycle of descent
Type c has also been put into practical use. An example of this is “Resolution 10
It is introduced in the article ``Development of a liquid crystal printer head with a printing speed of 7 pages/minute 1'' in the book/Ryu.

The present invention is intended to be used in a coordinate input device based on the realization of miniaturization of liquid crystal elements and high-speed inversion, and a configuration diagram showing one embodiment is shown in FIG. FIG. 2 shows a liquid crystal element in which 80 liquid crystal molecules are arranged in the horizontal direction and 40 in the vertical direction, and the small circles indicate the liquid crystal molecules. In the case of Figure 2, the liquid crystal elements are arranged at a pitch of 0.25 mm both vertically and horizontally.
Functions as two character frames.

FIG. 3 shows a timing diagram showing a method of driving a liquid crystal element. Figure 3 (al is the drive waveform for driving the liquid crystal element,
(bl is a diagram explaining the shutter function.

That is, it can be considered that (b) is the result of measuring the brightness of the incident light entering from the upper polarizing plate in the operating principle diagram shown in FIG. 1 with a not-shown brightness meter installed below the lower polarizing plate. Also (I
]) is synchronized with the drive waveform of (a). Figure 3(a)
t. From tl to t2 and after t2, a voltage is applied to the liquid crystal element, so the incident light does not pass through the liquid crystal element. t
, and t2, no voltage is applied to the liquid crystal element, so the incident light passes through the liquid crystal element. However, as the passing light changes as the liquid crystal molecules move, it becomes the waveform shown in Figure 3 (bl).Now, let Ta be the luminance stably obtained at a luminance smaller than the maximum value of the passing light of this liquid crystal element, and If it is detected when there is a passing light of
sec. When t is set to about 10 of T, Figure 3 (b
). Next, FIG. 3(C) shows a driving waveform that is driven ten cycles later than that in FIG. 3(a), and the luminance characteristic corresponding to (C) is shown in FIG. 3(d). Here (bl and (dl)
Since the detection time t of the passing light does not interfere with each other, when the liquid crystal element shown in FIG. 2 is sequentially driven from the 1st column of the 1st row to the 80th column, If the columns are sequentially driven at a timing of (C1) and the third column is driven at a timing that is ten cycles later than (C1), it will be possible to drive at a cycle of 0.25 m sec.

Now, in Figure 2, liquid crystal molecules are arranged in 40 rows and 80 columns.These 3200 liquid crystal molecules are divided into 80 blocks of 40 points each and driven simultaneously, and the calculation is performed by detecting which block the signal comes from. It is possible to detect which part of the 3200 liquid crystal molecules the light has entered.

Here, if 40 pieces in the vertical direction are considered as one block, only the position in the Y direction can be detected.

When driven using the above method, one block is driven at 40X O,2
It can be driven in 5=10 msec. Therefore 100 per second
Now, the liquid crystal surface shown in FIG. 2 can be scanned.

The scanning speed of 100 times/second is sufficient for use in online character recognition, and the resolution is 4.
It can be said that the number of books/mm is sufficient.

Next, an overall configuration diagram of one embodiment will be explained with reference to FIG. 4. 1
is an input section using the liquid crystal described above, 2 is a writing instrument with a built-in light receiving section, 3 is a liquid crystal display section, 4 is a drive circuit that drives the input section 1, and 5 is a control circuit that controls the drive circuit 4. It outputs to the sample circuit 6 every moment which liquid crystal is being driven. 7 is a drive circuit for the liquid crystal display section 3, and 8 is a control circuit for controlling the drive circuit 7. The sample circuit 6 samples and outputs the liquid crystal position currently being driven based on the signal from the writing instrument 2.

Now, as explained above, in the input section 1, even in the case of 40 rows and 80 columns, the total number of liquid crystal molecules is 3200, and the reversal speed of the liquid crystal is a.
The signal must be divided into 8o blocks of 40 points each, and as a result, the position in the Y direction can be determined, so it is necessary to identify which block the signal is coming from. There are various methods for this, such as a method in which the auxiliary identification light receiving section 9 receives the light and identifies which block the signal comes from, a method in which a transparent pressure-sensitive touch sensor is provided on the input section 1 and the signal output block is identified. The following methods can be considered, and these methods can be easily realized using well-known techniques. Here, the auxiliary identification section using infrared rays will be briefly explained.

FIG. 5 shows the infrared auxiliary identification section and clearly shows the relationship between the auxiliary identification light receiving section 9 and the writing instrument 2. The writing portion of the writing instrument 2 includes the light receiving section 1o described above, and an infrared light emitting source 11 configured to emit light in each direction is provided immediately above the light receiving section 10. The infrared light emitted from the infrared light source is received by the auxiliary identification light receiving section 9.

The auxiliary identification light receiving section 9 has a hole 12 in a rectangular parallelepiped block. Since there is a hole 12, only when the writing instrument 2 is on the extension line of the hole, an output above a certain level is obtained from the light receiving sensor 13, so it is easy to identify where the writing instrument 2 is located in the X direction.

Note that if liquid crystal molecules with a high reversal speed are used, there is no need to divide the liquid crystal into blocks, and the above-mentioned auxiliary identification section is not necessary.

As explained above, the coordinate values can be read by the sample circuit 6 based on the information from the writing instrument 2 and the auxiliary identification light receiving section 9 as well as the information from the control section 5.

(Effects of the Invention) As explained above, the present invention provides a writing area for a plurality of characters or one to three lines as an input area for writing characters, and provides a display area immediately above the writing area to write text. In the case of input, it is possible to check the text that has been input up to that point at the time of writing and by holding the writing instrument directly. Therefore, the normality of recognition and the validity of the input text can be confirmed at the same time.

Furthermore, since the input section and the display section can be constructed from the same liquid crystal element, it is possible to reduce the manufacturing cost of the device.

The coordinate input device of the present invention is expected to be used in the future as a coordinate input device for an online character recognition device.

[Brief explanation of the drawing]

Figure 1 (a) and (b) are diagrams of the principle of liquid crystal operation, Figure 2 is 4
FIG. 3 is a timing diagram showing a method of driving the liquid crystal element 9, FIG. 4 is an overall configuration diagram of an embodiment of the present invention, and FIG. It is an auxiliary identification diagram. 1: Input section, 2: Writing instrument, 3: Liquid crystal display section, 9: Auxiliary identification light receiving section.

Claims (3)

[Claims] (1) In an online character recognition device that recognizes characters by detecting the movement of the tip of a writing instrument, there is an input liquid crystal element that selectively reflects external light, and a light receiving section that receives the light reflected by the liquid crystal element. a writing instrument having: a detection means for detecting an input coordinate position by the writing instrument from the timing of an electric signal that drives an input liquid crystal element and the timing of a signal received by the writing instrument; and an input from the coordinate position detected by the detection means. recognition means for recognizing the written characters;
1. A coordinate input device comprising a display liquid crystal element that displays the recognition result of the recognition means by selectively reflecting external light. (2) The coordinate input device according to claim 1, wherein the input liquid crystal element and the display liquid crystal element are constituted by a single liquid crystal element. (3) The online character recognition device according to claim 1, wherein the writing instrument has a light emitting section, and the light from the light emitting section is used as external light that enters the input liquid crystal element.