JPH0968954A - Coordinates input device with liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform display by inputting a RGB signal having e.g. smaller resolving power than that of the physical dot constitution of a liquid crystal display part and to make an indicating position by an indicator correspond to the display position of the liquid crystal display part in a coordinate input device with a liquid crystal display. SOLUTION: This device 15 is provided with a liquid crystal display having the dot constitution of specified resolving power and performing picture display by inputting a RGB signal supplied from a personal computer 11. The device is provided with a clock signal generating part 29 for generating a clock corresponding to a resolving power mode smaller than the resolving power mode of the dot constitution, a resolving power mode deciding part 28 for deciding the high/low level of the resolving power mode of the analog RGB signal, a selecting part 28 for selecting a desired clock signal from the clock signal generating part when it is decided that the resolving power mode of the analog RGB signal is low and a display driving part for displaying the picture by means of the inputted analog RGB signal on a part of the screen of the liquid crystal display by using the selected clock signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a display device for performing a display operation based on analog RGB signals generated in a computer such as a personal computer and is capable of supporting various analog RGB signals having different resolution modes. Attached coordinate input device.

[0002]

2. Description of the Related Art A computer such as a personal computer is provided with a display device (monitor) as an output device. The display operation of this display device is an analog RGB signal (hereinafter referred to as "RGB") generated and output by a display control unit in the computer. Signal)). As a personal computer,
For example, NEC PC98 series, Macintosh,
Different manufacturers or different models such as IBM-PC / AT and compatibles thereof are on the market. These personal computers have built-in RGB signal generation means and are provided with an RGB signal output terminal section. The display device connected to the computer captures the display signal through the RGB signal output terminal portion. CRT as the current display device of computer
(Cathode ray tube) is the mainstream.

On the other hand, a display device connected to a computer is designed so that its resolution (fineness of screen) mode matches or corresponds to the frequency of an RGB signal (computer resolution mode) generated by the computer. It is common to In other words, the frequency of the RGB signal differs depending on the model in the computer. For example, in the resolution mode, in the normal mode (VGA panel), 640 (horizontal pixel number) × 480 (vertical pixel number) or 640 A display device in the resolution mode of × 400 is used. Also, in Windows etc., depending on the driver, 640x480, 800x600, 1
It can be set to any one of the resolution modes such as 024 × 768. In the case of Windows, the resolution mode of the computer is set to match the resolution of the connected display device.

More specifically, the fineness of the screen of the display device, that is, the resolution is strictly determined by the signal and the number of pixels. The resolution includes horizontal resolution in the horizontal direction and vertical resolution in the vertical direction. The vertical resolution is uniquely determined by the number of scanning lines. However, in interlaced driving such as that of a television, the vertical resolution is reduced to about 70% of the number of scanning lines. On the other hand, the horizontal resolution is limited by the number of horizontal pixels when the band of the signal is wider than the band determined by the number of horizontal pixels, and conversely, when the band of the signal is narrower than the band determined by the number of horizontal pixels. Limited by the band. In general, the small liquid crystal television is often the former case, and the latter case is increasing due to the large size and high definition of the liquid crystal display.
Since the computer display is driven digitally, the number of pixels and the resolution are matched as described above.

When a CRT is connected as a display device to a computer whose resolution mode is fixed to one type and the resolution mode of the computer and the resolution mode of the CRT do not match, C
Conventionally, there has been a method called multi-sync as a technology that enables display in RT. According to this multi-sync, the CRT resets its own resolution based on the RGB signal given from the computer, and performs the display operation using the entire screen in the resolution mode that matches the resolution mode of the RGB signal. Even if the CRT has a multi-sync function, for example, 1024 × 768.
The multi-sync CRT that is adapted to the resolution mode of 1 cannot support RGB signals in the resolution mode of more than 1280 × 1024.

[0006]

As a display device for a computer, another type of display device, that is, for example, a coordinate input device with a liquid crystal display (hereinafter referred to as "LC for convenience of description") is used.
"D tablet") is known. The LCD tablet includes a liquid crystal display unit, a liquid crystal display unit having a function as a display device, a coordinate detection unit, and a pen-type position indicator. And a coordinate input device having a function as an input device capable of inputting position data (coordinate data) designated by. Since the LCD tablet enhances the input operability of the computer, there has been a great demand in recent years to use the LCD tablet as an input / display device of the computer.

On the other hand, when the LCD tablet is used as a display device of a computer, there is a problem of matching between the resolution of the liquid crystal display unit used for the LCD tablet and the resolution of the RGB signal output from the computer.

As is well known, the liquid crystal display portion of an LCD tablet is constructed by arranging a large number of pixels (pixels) vertically and horizontally so as to form a rectangular display area.
When each pixel corresponds to one dot, the dots arranged vertically and horizontally form a rectangular display area, which is formed as a dot configuration. The resolution of the liquid crystal display unit in the LCD tablet is usually represented by the number of dots in the physical dot configuration. That is, the resolution of the liquid crystal display unit is expressed as n × m dots, where n is the number of dots in the vertical direction and m is the number of dots in the horizontal direction. Since the number of dots is fixed in the liquid crystal display section of the LCD tablet, the resolution mode is kept constant.

Since the liquid crystal display section of the LCD tablet has the physical dot configuration as described above, basically, the resolution mode of the RGB signal output from the computer,
It must match the resolution mode of the display section of the LCD tablet. That is, if the resolution of the liquid crystal display part of the LCD tablet is 640 × 480 dots,
If the resolution of the RGB signal is also not 640 × 480, the problem that the display cannot be performed on the display unit is raised. For example, 640 × 4, which has a lower resolution of RGB signals.
Even if it is 00, since the clock frequency is different,
It was not possible to display on the liquid crystal display of the CD tablet.

Further, when considering an LCD tablet provided with a liquid crystal display section having a relatively high resolution, in recent years, the resolution of the display tends to become higher and higher due to, for example, Windows, which is intended for a CRT as a display device. However, it is not intended for the liquid crystal display portion of the LCD tablet. If it is necessary to prepare an LCD tablet equipped with a high-resolution liquid crystal display unit compatible with a high-resolution computer, the liquid crystal display unit will be expensive, and depending on the software to be operated, an LCD corresponding to each resolution will be provided. Raise the problem of having to prepare a tablet.

From the above, when the RGB signals output from the computer are used to display on the liquid crystal display section of the LCD tablet, the RGB signal having a resolution smaller than the resolution of the physical dot configuration of the liquid crystal display section. , Or even if an RGB signal having a higher resolution is input, it is desired that the image can be displayed. For example, in the case of an LCD tablet having a liquid crystal display unit having a resolution mode of 1024 × 768 dots, lower resolution modes such as 640 × 400 dots, 640 × 480 dots, 800 × 600 dots, or 1280 × 1024 dots, 1600 × 1
It is desirable to be able to display using RGB signals of each higher resolution mode such as 200 dots.

Regarding the liquid crystal display section of the LCD tablet, when the RGB signal having a lower resolution is used for the physical dot configuration of the liquid crystal display section and a part of the display screen is used for display, At the position actually displayed, L
Since the coordinates output from the CD tablet do not correspond one-to-one, there is a problem that the actual position indicated by the position indicator and the position of the pointer indicating the position indicator displayed on the display screen are displaced. did.

Further, in the LCD tablet having a structure in which the liquid crystal display unit and the coordinate input device are superposed (laminated), regarding the relationship (consistency) between the resolution of the liquid crystal display unit and the resolution of the input surface of the coordinate input device. Also needs to be considered. As described above, the resolution of the liquid crystal display unit is represented by the dot configuration, whereas the resolution of the tablet (coordinate input device) is usually 0.1 m as the resolution.
It is generally expressed in millimeters (mm) such as m and 0.05 mm. Further, in a tablet in which a liquid crystal display unit is stacked, it is becoming more common to represent the resolution of the tablet by how many identifiable points can be taken per pixel (or one line). In such a case, the pitch between pixels also has a great influence on the resolution of the LCD. On the other hand, the pixel pitch is not a problem in the resolution of the liquid crystal display.

A first object of the present invention is to provide an RGB signal having a resolution smaller than the physical dot configuration of the liquid crystal display unit when displaying on the liquid crystal display unit using the RGB signal output from the computer. Or RG with larger resolution
It is an object of the present invention to provide a coordinate input device with a liquid crystal display that can display even if a B signal is input.

A second object of the present invention is to provide an actual position indicated by a position indicator on a coordinate input device when displaying on a liquid crystal display unit using RGB signals output from a computer. Another object of the present invention is to provide a coordinate input device with a liquid crystal display in which the position indicating the position of the position indicator displayed on the liquid crystal display unit always matches.

A third object of the present invention is to have a structure in which a liquid crystal display unit and a coordinate input device are laminated, and a display surface of the liquid crystal display unit and an input surface of the coordinate input device have a specific correspondence relationship. In this case, when a display is performed using a part of the liquid crystal display unit, there is provided a coordinate input device with a liquid crystal display in which the input on the coordinate input device and the display on the liquid crystal display unit exhibit consistency. Especially.

[0017]

The coordinate input device with a liquid crystal display according to the first aspect of the present invention (corresponding to claim 1) is for achieving the first object.
A liquid crystal display unit having a dot configuration corresponding to one specific resolution mode is provided, and an analog RGB signal supplied from a computer such as a personal computer is input, and display is performed on the liquid crystal display unit based on the analog RGB signal. A liquid crystal display (device) and a coordinate input device superimposed on the liquid crystal display, and further, a resolution mode determination unit that determines the resolution mode of the input analog RGB signals, and a input. When the resolution mode determination unit determines that the resolution mode of the analog RGB signal is different from the resolution mode of the dot configuration of the liquid crystal display, it is possible to display an image by using a part of the screen of the liquid crystal display. To
And a conversion unit that converts the input analog RGB signal.

In the first aspect of the present invention, the resolution mode determination unit determines the resolution mode of the input analog RGB signal, and compares the difference with the resolution mode of the liquid crystal display provided to compare the liquid crystal. The converter converts the input analog RGB signal into a desired display drive signal so that an image can be displayed using a part of the screen of the display.

A coordinate input device with a liquid crystal display according to a second aspect of the present invention (corresponding to claim 2) achieves the first object and corresponds to one specific resolution mode, as in the first aspect of the invention. A liquid crystal display (device) having a liquid crystal display unit having a dot configuration, configured to receive an analog RGB signal supplied from a computer such as a personal computer and to perform display on the liquid crystal display unit based on the analog RGB signal; , A clock signal generator for generating a clock signal corresponding to each of a plurality of resolution modes lower than the resolution mode of the dot configuration of the liquid crystal display. Section and input analog RGB
A resolution mode determination unit that determines whether the resolution mode of the signal is lower than the resolution mode of the dot configuration of the liquid crystal display, and a resolution mode when the resolution mode of the input analog RGB signal is lower than the resolution mode of the dot configuration. When the determination unit determines, the selection unit that selects the clock signal corresponding to the resolution mode of the analog RGB signal from the clock signal generation unit and the selected clock signal is input to a part of the screen of the liquid crystal display. And a display drive unit that displays an image by the generated analog RGB signals.

In the second aspect of the present invention, the resolution mode determination section determines the resolution mode (or display mode) of the input analog RGB signal and compares it with the dot configuration (resolution mode) of the liquid crystal display equipped. When the resolution mode is low, a clock signal suitable for the resolution mode is selected by the clock signal generation unit, and the clock signal is applied to the liquid crystal display to compare the input analog signal with the dot configuration of the liquid crystal display. Even when the resolution mode of the RGB signal is low, it is possible to display an image by using a part of the screen of the liquid crystal display.

A coordinate input device with a liquid crystal display according to a third aspect of the present invention (corresponding to claim 3) achieves the first object and corresponds to one specific resolution mode, as in the first aspect of the invention. A liquid crystal display (device) having a liquid crystal display unit having a dot configuration, configured to receive an analog RGB signal supplied from a computer such as a personal computer and to perform display on the liquid crystal display unit based on the analog RGB signal; And a resolution determining device for determining whether or not the resolution mode of the input analog RGB signal is higher than the resolution mode of the dot configuration of the liquid crystal display. Mode determination unit and input analog RGB
When the resolution mode determination unit determines that the resolution mode of the signal is higher than the resolution mode of the dot configuration, the thinning unit that thins the input analog RGB signal and the thinned analog RGB signal is used for the liquid crystal display. It is configured to include a display drive unit that displays an image on a part of the screen.

In the third aspect of the present invention, the resolution mode determination section determines the resolution mode (or display mode) of the input analog RGB signal and compares it with the dot configuration (resolution mode) of the equipped liquid crystal display. If the resolution mode is high, the thinning unit appropriately thins the input analog RGB signals, so that the resolution mode of the input analog RGB signals is higher than that of the dot configuration of the liquid crystal display. Also, it has become possible to display images using part of the LCD screen.

A coordinate input device with a liquid crystal display according to a fourth aspect of the present invention (corresponding to claim 4) is characterized in that, in the first to third aspects, an image display area set in a part of a screen of the liquid crystal display is positioned. It is configured so that it can be moved to any desired position on the screen using an indicator.

A coordinate input device with a liquid crystal display according to a fifth aspect of the present invention (corresponding to claim 5) is for achieving the second object, and in the fourth aspect, a position indicator on the screen. When moving the image display area by using, so that the display object (pointer or the like) of the position indicator on the liquid crystal display and the actual position of the position indicator match.
It is configured so as to have means for eliminating the offset of both.

A coordinate input device with a liquid crystal display according to a sixth aspect of the present invention (corresponding to claim 6) achieves the second and third objects. In the first to third aspects, the input is made. The resolution of the coordinate input device is corrected with respect to the resolution of the analog RGB signal, and the resolution of the coordinate input device and the resolution of the coordinate input device are matched with each other.

A coordinate input device with a liquid crystal display according to a seventh aspect of the present invention (corresponding to claim 7) is the coordinate input device according to any one of the first to fourth aspects of the present invention, wherein an inner portion of an image display area which is a part of a screen of the liquid crystal display It is configured to include means for identifying the outer portion.

[0027]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows the configuration of a computer system equipped with a coordinate input device with a liquid crystal display according to the present invention. The computer 11 is, for example, a personal computer (personal computer), and has a CRT 12 as an output device.
Is provided. The computer 11 has an analog RGB signal generation unit 13 built therein, and generates an analog RGB signal for performing necessary display on the CRT 12 here. Computer 1
1 includes an output terminal unit 14 for outputting the analog RGB signal generated by the analog RGB signal generation unit 13. The CRT 12 is connected to the computer 11 via the output terminal unit 14, and extracts the analog RGB signal from the computer 12 via the output terminal unit 14. In the present embodiment, in addition to the CRT 12, a coordinate input device with a liquid crystal display (hereinafter referred to as LCD tablet) 15 is connected.
It is taken out via a distributor 16 for distributing a signal to the D tablet side. CRT12 and LCD tablet 1
When connecting any one of the five, the distributor 16 is not necessary and the cable is directly connected to the output terminal portion 14.

The LCD tablet 15 has a liquid crystal display section and a coordinate input device. The liquid crystal display unit includes a rectangular display screen region formed by arranging a large number of pixels (pixels), that is, dots in a matrix, for example, and is formed as a dot configuration. This dot structure is a physical structure and is fixed, and depending on the number of dots, LC
The resolution mode of the display unit of the D tablet is determined. The coordinate input device also includes a position detection device that generates, as coordinate data, a position indicated by a position indicator such as a pen-type position indicator (electronic pen). The position detection device includes a coordinate input surface and a coordinate calculation circuit. The coordinate input surface is common to the display screen of the liquid crystal display section, that is, both are superposed and integrally formed in a laminated state. When you use the electronic pen to specify the position on the coordinate input surface and input, a signal related to the position is output from the coordinate calculation circuit, and the position is specified based on the final position data (coordinate data). Corresponding points are displayed on the display screen of the liquid crystal display.

When a position is specified on the coordinate input surface of the LCD tablet 15 using an electronic pen, the specified position is detected and the coordinate data of the position is obtained. The coordinate data obtained by the coordinate input device is supplied to the computer 11 via the cable 17 for RS232C. The analog RGB signal generated by the analog RGB signal generation unit 13 of the computer 11 is input to the LCD tablet 15 via the output terminal unit 14 and the distributor 16 and the cable 18.

In the configuration shown in FIG. 1, the frequency of the analog RGB signal generated by the analog RGB signal generator 13 of the computer 11, that is, the resolution mode, is set uniquely for each computer and is constant. Is. Further, the resolution mode of the liquid crystal display section of the LCD tablet 15 has a physical dot configuration (generally n ×
It is fixed by m dots). The resolution mode of the computer 11 and the resolution mode of the liquid crystal display section of the LCD tablet 15 do not necessarily match. As will be described later, even when the resolution modes of the computer 11 and the LCD tablet 15 do not match, it is possible to display on the liquid crystal display unit of the LCD tablet 15. Although FIG. 1 shows an example in which the LCD tablet 15 is connected to the computer 11, the display operation can be performed even if the LCD tablet 15 is connected to a computer having another resolution mode different from the resolution mode of the computer 11. It can be carried out.

LCD tablet 15 according to FIGS.
The internal configuration of will be described in detail. FIG. 2 is a block diagram showing a hardware circuit configuration. First, the liquid crystal display section of the LCD tablet 15 will be described. 4 to 6 are block diagrams showing functional units realized by the CPU with respect to a portion related to the liquid crystal display unit.

In FIG. 2, 21 is an RGB signal port,
22 is an RS232C port. RGB signal port 2
Through 1, the signal generated by the analog RGB signal generation unit 13 of the computer 11 is input. Analog RG
The analog RGB signal generated by the B signal generation unit 13 is
Strictly speaking, analog RG in a narrow sense including display information (R, G, B)
A B signal 23 and a horizontal synchronizing signal (HSYNC) and a vertical synchronizing signal (VSYNC) 24 (hereinafter referred to as horizontal / vertical synchronizing signal 24) are included. The analog RGB signal 23 input through the RGB signal port 21 is input to the A / D converter 25, where it is converted into a digital RGB signal 26. The digital RGB signal 26 is displayed on the liquid crystal display 27.
And is used as a signal for causing the liquid crystal display 27 to perform a display operation. The horizontal / vertical sync signal 24 is
It is input to the CPU 28 and the dot clock reproduction circuit 29. The CPU 28, which receives the horizontal / vertical synchronization signal 24,
The frequency of the horizontal sync signal is measured, and the frequency of the vertical sync signal is measured. Each frequency is measured by obtaining the period of each of the horizontal synchronizing signal or the vertical synchronizing signal and calculating the frequency based on that. Further, the CPU 28, based on the frequency of the horizontal synchronizing signal and the frequency of the vertical synchronizing signal,
The resolution mode of the analog RGB signal output from the computer 11 is determined.
Next, the CPU 28 compares the resolution of the dot configuration of the liquid crystal display 27 with the resolution of the input analog RGB signal, and determines the magnitude relationship between them. On the other hand, the dot clock reproduction circuit 29 reproduces and outputs a clock signal required for display on the liquid crystal display 27 using the input horizontal / vertical synchronization signal 24 and in accordance with an instruction code given from the CPU 28. Clock recovery circuit 2
A plurality of well-known voltage-controlled oscillators or a clock generator capable of outputting a plurality of clock signals are used for 9. Since the clock signal reproduced by the clock reproducing circuit 29 and the input analog RGB signal are not always synchronized, a function is provided to adjust the phases of both by a well-known means so as to achieve synchronization. ing. Further, if the liquid crystal display is capable of inputting analog signals, the A / D converter 25 is not necessary and the signals are directly input from the RGB signal port to the liquid crystal display.

The relationship between the resolution mode (dot structure) of the liquid crystal display and the resolution mode (frequency) of the analog RGB signal will be described. Regarding the relationship between the dot configuration of the liquid crystal display and the dot clock frequency of the analog RGB signal, for example, 21.053 MHz in the case of 640 × 400 dots, 25.175 MHz in the case of 640 × 480 dots, and 800 × 600 dots in the case of 640 × 480 dots. A typical correspondence relationship is 40 MHz in the case, and 65 MHz in the case of 1024 × 768 dots. Further, the dot configuration is higher than 1024 × 768 dots, that is, 1280 × 1024 dots, 1600 × 1200.
With respect to dot configurations such as dots, there is a corresponding dot clock frequency of the analog RGB signal.
As described above, since there is a predetermined correspondence between the resolution mode of the liquid crystal display and the frequency of the analog RGB signal, when the display operation is performed using a certain specific liquid crystal display, the dots of the liquid crystal display are displayed. It is necessary to use a clock signal with a frequency that corresponds to the configuration.

The liquid crystal display 27 according to the present embodiment has a dot structure of 1024 × 768 dots. LCD tablet 1 including liquid crystal display 27
5 is connected to the computer 11 that is matched in terms of resolution in a normal sense, the dot clock frequency of the analog RGB signal generated by the analog RGB signal generation unit 13 of the computer 11 is 65 MHz. is there. When this analog RGB signal is input and a display operation is performed on the liquid crystal display 27, the dot clock reproduction circuit 29 provides the liquid crystal display 27 with a clock signal having a frequency of 65 MHz. In this case, as described above, the analog RG provided from the computer 11
The horizontal and vertical synchronizing signals of the B signal are input to the CPU 28,
The CPU 28 obtains the frequency of the analog RGB signal,
This frequency information is input to the dot clock reproducing circuit 29 as an instruction code, and the dot clock reproducing circuit 29 outputs a clock signal having a frequency of 65 MHz based on the information. The liquid crystal display 27 receives the clock signal supplied from the dot clock reproduction circuit 29, and receives the digital RGB signal 2 from the A / D converter 25.
The display operation is performed by using 6.

In the LCD tablet 15 according to the present embodiment, even though the liquid crystal display 27 of 1024 × 768 dots is provided as the dot configuration, the frequency of the input analog RGB signal is a frequency other than the above-mentioned 65 MHz. Also, the display operation can be performed. In other words, the analog RGB signal generation circuit 1 of the computer 11 to which the LCD tablet 15 is connected.
Even when the frequency of the analog RGB signal output from 3 is a lower frequency other than the above-mentioned 65 MHz or a higher frequency, a part of the screen of the liquid crystal display 27 is used by using the analog RGB signal. It can be used to display.

The LCD tablet 15 is connected to the output terminal section 14 of the computer 11 by using the cable 18, and as a result, the analog RGB signals are output via the RGB signal port 21.
When a signal is input, as described above, the CPU 28 measures the frequency of the input analog RGB signal, determines the resolution mode of the analog RGB signal based on the measured frequency, and further determines the resolution of the input analog RGB signal. The resolution of the dot configuration of the liquid crystal display 27 is compared to determine the magnitude relationship between them. The CPU 28 determines the dot clock reproduction circuit 29 based on the determined magnitude relationship.
An instruction code for selecting a clock signal to be output to. The dot clock recovery circuit 29 is a CPU
The clock signal of the selected frequency is output according to the instruction code from 28.

The resolution mode of the analog RGB signal is 10
If the dot configuration is smaller than 24 × 768 dots, the dot clock recovery circuit 29 outputs the following clock signal. 21.0 when the resolution mode of the analog RGB signal corresponds to 640 × 400 dots
53MHz clock signal is selected, analog RGB
When the resolution mode of the signal corresponds to 640 × 480 dots, the clock signal of 25.175 MHz is selected, and the resolution mode of the analog RGB signal is 800 × 60.
When 0 dots are supported, a 40 MHz clock signal is selected. As described above, when the resolution mode of the analog RGB signal is smaller than the dot configuration of 1024 × 768 dots, the clock signal corresponding to the resolution mode of the input analog RGB signal is selected, and the selected clock signal is a dot. It is given from the clock reproducing circuit 29 to the liquid crystal display 27. Liquid crystal display 27
Then, using the given clock signal, 1024 × 7
Display is performed using a part of the screen having a dot configuration of 68 dots. That is, display is performed based on the dot configuration corresponding to the clock signal. For example, when the clock signal is 21.053 MHz, 1024 × 768
Of the dots, 640 × 400 dots are used.
Which of the dots on the screen to use can be arbitrarily determined. An example thereof is shown in FIG. In FIG. 3, 31 is a screen of 1024 × 768 dots, 32
Is an image display area of 640 × 400 dots.

When the components of the LCD tablet 15 such as the CPU 28 for performing the above-mentioned operations are shown in a functional configuration,
As shown in FIG. 4, elements that are substantially the same as the elements shown in FIG. 2 are assigned the same reference numerals.
In FIG. 4, reference numeral 41 denotes a clock signal generation unit (corresponding to the dot clock reproduction circuit 29) that generates at least clock signals corresponding to a plurality of resolution modes lower than the resolution mode of the dot configuration of the liquid crystal display 27, 4
2 is a resolution mode determination unit that determines whether the resolution mode of the input analog RGB signal is lower than the resolution mode of the dot configuration of the liquid crystal display 27, and 43 is
If the resolution mode of the input analog RGB signal is lower than the resolution mode of the dot configuration, the resolution mode determination unit 4
When 2 is determined, the selection unit that selects the clock signal corresponding to the resolution mode of the analog RGB signal from the clock signal generation unit 41, the input 44 to the part of the liquid crystal display 27 using the selected clock signal. It is a display drive unit that performs display using the generated analog RGB signals.

On the other hand, when the resolution mode of the analog RGB signal is larger than the dot configuration of 1024 × 768 dots, the dot configuration corresponding to the analog RGB signal is halved vertically and horizontally. A frequency clock signal is selected. That is, for example, 1280
In the case of × 1024 dots, half thinning is performed and 64
To be 0x512 dots, 1600x120
In case of 0 dots, half thinning is performed and 800 × 60
The clock signal output from the dot clock recovery circuit 29 is selected so that it has 0 bits. Analog RGB
The process of thinning out the signal is performed by analog RGB which is the original signal.
It is performed by selecting a clock signal having a frequency that is ½ of the frequency of the clock signal corresponding to the signal. As described above, when the resolution mode of the analog RGB signal is larger than the dot configuration of 1024 × 768 dots, the clock signal having a frequency half that of the clock signal corresponding to the resolution mode of the input analog RGB signal is selected. The selected clock signal is applied to the liquid crystal display 27 from the dot clock reproduction circuit 29.
On the liquid crystal display 27, display is performed using a given clock signal and utilizing a part of the screen having a dot configuration of 1024 × 768 dots. The display mode using a part of the liquid crystal display 27 is substantially the same as the example shown in FIG.

The functional parts of the components of the LCD tablet 15, such as the CPU 28, which perform the above operations, are as follows.
As shown in FIG. 5, elements that are substantially the same as the elements shown in FIG. 4 are assigned the same reference numerals.
In FIG. 5, reference numeral 51 is a resolution mode determination unit that determines whether the resolution mode of the input analog RGB signal is higher than the resolution mode of the dot configuration of the liquid crystal display 27, and 52 is the input analog RGB signal. When the resolution mode determination unit 51 determines that the resolution mode of 4 is higher than the resolution mode of the dot configuration of the liquid crystal display 27, the thinning unit 44 for thinning the analog RGB signal, 44
Is a display drive unit as described above, which uses a thinned-out analog RGB signal to display a part of the liquid crystal display 27 by the input analog signal. The thinning unit 52
Is actually composed of, for example, a clock signal generation unit that generates a clock signal having a frequency of 1/2 of the original clock signal and a selection unit that selects the clock signal.

The characteristic structure of the LCD tablet 15 described in the above preferred embodiment is further conceptually shown in a block diagram as shown in FIG. That is, the liquid crystal display 27 having a dot configuration (1024 × 768 dots in the above embodiment) corresponding to one specific resolution mode is provided, and the analog RGB signals (23, 24) supplied from the computer 11 are input to the analog display. RGB
It is an LCD tablet 15 which is displayed on the liquid crystal display 27 based on a signal, and which is an analog R
When the resolution mode determination unit 61 determines the resolution mode of the GB signal and the resolution mode determination unit 61 determines that the resolution mode of the input analog RGB signal is different from the resolution mode of the dot configuration described above, the liquid crystal display 27
Is configured to include a conversion unit 62 that converts an input analog RGB signal so that display can be performed using a part of the above.

In the configuration of the above-described preferred embodiment, when the resolution mode of the liquid crystal display 27 and the resolution mode of the input analog RGB signal match, display is performed using the entire screen of the liquid crystal display 27. Of course, the corresponding clock signals can be output, as can be done.

In the preferred embodiment described above, the dot configuration of the liquid crystal display 27 is 1024 × 768 dots, but the dot configuration of other resolution modes can be similarly configured. In this case, depending on the resolution mode of the liquid crystal display 27, a resolution mode smaller than the resolution mode or a resolution mode larger than the resolution mode is determined.

According to the above preferred embodiment, the LCD
In the liquid crystal display section of the tablet 15, even if the display is in a resolution mode corresponding to a dot configuration smaller than the actual physical dot configuration of the liquid crystal display 27, or a dot configuration larger than the actual dot configuration of the liquid crystal display 27. Even in the case of the display in the resolution mode, the display can be easily performed by using a part of the screen of the liquid crystal display 27.

It should be noted that the liquid crystal display 27 and the coordinate input surface 74a are superposed on each other, and the resolution of the display screen and the resolution of the coordinate input surface are originally associated with each other so as to have a required consistency. In the LCD tablet 15, when displaying an image using a part of the liquid crystal display, it is necessary to pay attention to the following points. That is, when the display is performed by using a part of the display screen of the liquid crystal display 27, the number of vertical and horizontal pixels used on the display screen is reduced, so that the resolution as the liquid crystal display is reduced, but the pitch between the pixels is changed. do not do. Therefore, it is necessary to correct the signal processing for extracting the position data so that the resolution on the side of the coordinate input device matches the resolution of the liquid crystal display, and the CPU 28 has a correction means for performing such correction processing. I have it. More specifically, for example, the resolution of the liquid crystal display 27 is 102
If the resolution is 4 × 768 dots, the higher resolution 12
When displaying a signal of 80 × 1024, 1280 × 10
24 is halved and displayed as 640 × 512. At this time, the pitch does not change and the pixel is forced to be halved within the apparatus, so that the resolution of the coordinate input apparatus is set to the standard halving for consistency.

Returning to FIG. 2, the structure of other parts will be described. A RAM is provided inside the CPU 28, and a non-volatile memory 71 is provided outside. The memory 71 stores data necessary for processing. The data includes resolution mode data of the liquid crystal display 27 and offset data described later. The liquid crystal display 27 is preferably of the backlight type and the backlight 7
Equipped with 2. Note that the backlight may not be provided. The signal for driving the backlight 72 is the CPU 28.
From an inverter 73 that converts the DC signal from the AC signal into an AC signal. In addition to the above-mentioned liquid crystal display unit, the LCD tablet 15 is provided with a coordinate input surface 74a and a coordinate calculation circuit 74b which are parts of the coordinate input device. The coordinate input surface 74a and the coordinate calculation circuit 74b are provided with a configuration for taking out position data (coordinate data) designated by a position indicator such as an electronic pen (not shown). The signal detected on the coordinate input surface 74a becomes position data in the coordinate calculation circuit 74a, is sent to the CPU 28, and is used for processing in the CPU 28. The obtained position data is the RS232C driver 7
5, sent via the RS232C port 22 and the cable 17 to the computer 11 side. The computer 11 performs necessary processing based on the input position data.

The switch 76 is for the LCD tablet 1.
The switch is arranged on the case No. 5 and can be operated from the outside. A normal mode and an image moving mode can be selected by the switch 76. When the switch 76 is turned on, the image moving mode is set, and the position of a part of the image display area of the screen of the liquid crystal display 27 can be moved to an arbitrary position on the screen by the position indicator.

Next, a function (image moving mode) for enabling the liquid crystal display 27 to move the image display area displayed by using a part of the screen on the screen will be described. As shown in FIG. 3, in the case of displaying a resolution mode corresponding to a dot configuration smaller than the dot configuration of the liquid crystal display 27 or displaying a resolution mode of a large dot configuration, an image display area is displayed in a part of the screen 31. 32
Is formed. This image display area 32 has an electronic pen 81.
It is possible to move using, for example, as shown by the arrow. Thereby, the image display area 32 can be provided at an arbitrary position on the screen.

In the LCD tablet 15, the screen 31 of the liquid crystal display 27 and the coordinate input surface 74a of the coordinate input device.
In a normal case where all the dots are used to display an image on the entire screen, the electronic pen 81 indicates a position on the screen 31 as the coordinate input surface. When an input is made, it is displayed at the same position on the screen 31. Such a function of the LCD tablet 15 is configured to be realized even when an image is displayed by using a part of the screen 31.

When the switch 76 shown in FIG. 2 is off, the normal mode is set, and when the switch 76 is turned on, the image moving mode is set. First, the image moving mode when the switch 76 is turned on will be described. When the image moving mode is set, the instruction operation by the electronic pen 81 is to specify the position of the image displayed on the screen 31 (corresponding to the coordinate input surface 74a) of the liquid crystal display 27, and via the RS232C cable 17. It is not output as coordinate data to the computer 11.

According to the flow chart shown in FIG. 7,
The operation of the image moving mode will be described. When the electronic pen 81 is pen-downed in the image display area 32, a determination step S1
1 is determined as YES, and the coordinate value (X1,
Y1) is obtained by the coordinate calculation circuit 74b, and the coordinate values are stored in the RAM of the CPU 28 (step S1).
2). With the pen-down electronic pen 81, move the electronic pen 81 to the coordinate input surface 7 so that the pen tip switch is turned on.
For example, it is assumed that the button 4a is pressed and moved to the right by ΔX and moved downward by ΔY, and then the pen is moved up. Then, it is determined in the determination step S13 whether or not the pen is up,
When YES, the coordinate values (X2, Y
2) is obtained by the coordinate calculation circuit 74b, and the CPU2
8 is stored in the RAM (step S14). afterwards,
In the CPU 28, the coordinate values (X1, Y1) and (X2, Y
The difference Δ (X, Y) from 2) is obtained as offset data, and the data is stored in the RAM and the non-volatile memory 71 (step S15).

To move the position of the image display area 32 on the screen 31 of the liquid crystal display 27, the CPU 28 uses the RAM.
This is performed by converting the offset data stored in (1) into the number of dots and offsetting the display control signal output to the liquid crystal display 27 by the number of dots (step S16). As a result, the image display area 32 is moved to a new image display area 32 '. Final step S17
Then, it is determined whether or not the image moving mode has ended. When the switch 76 is turned off, it is determined that the mode has ended.

When the coordinate input device is set to the normal mode by turning off the switch 76, the position input operation is performed with the electronic pen on the new image display area 32 'on the screen 31, that is, the coordinate input surface 74a. Then, the coordinate input device processes the coordinate data as shown in the flowchart of FIG. That is, when an input for designating a certain position is performed using the electronic pen 81 in the image display area 32 ', the coordinate calculation circuit 74b uses the coordinate data (X,
Y) is output, and the CPU 28 receives this coordinate data (step S21). The coordinate data (X, Y) is coordinates determined with the origin P (0, 0) of the image display area 32 'as a reference. Therefore, the CPU 28 receiving the coordinate data (X, Y) from the coordinate calculation circuit 74b adds the offset data ΔX, ΔY stored in the RAM to the coordinate data (X, Y) to correct the offset data (X, Y) (step S22). Then the CPU
28 outputs the corrected coordinate data (X ', Y') to the computer 11 (step S23). By this operation, the normal L for the image display area 32 '
The function as a CD tablet is realized.

According to the preferred embodiment of the image moving mode described above, even when an image is displayed with a smaller dot configuration that uses a part of the physical dot configuration of the liquid crystal display 27, the electronic pen 81 is used. Can be used to move the image display area to an arbitrary position on the screen 31, and coordinate data offset by the moved distance can be output to the computer 11. The position of the
The normal function of the tablet 15 can be realized.

Since the offset data is stored in the non-volatile memory 71, the LCD tablet 15
Even when the power is turned on again, the offset data does not disappear and there is an advantage that it is not necessary to reset the data.

As another preferred embodiment, when the position on the screen 31 of the liquid crystal display 27 to be displayed is designated by the electronic pen 81, the offset amount of the display position is obtained and the electronic pen 81 is displayed on the screen 31. The offset correction is performed on the coordinate data generated by specifying with, and which position is used as the image display area is calculated, and the effective area as the coordinate input surface of the coordinate input device and the display area on the liquid crystal display 27 are calculated. It can also be configured to match. With this configuration, in the LCD tablet 15, when the original dot configuration of the liquid crystal display 27 is displayed with a small dot configuration that uses a part of the original dot configuration, the effective range of the tablet unit can correspond to the liquid crystal display unit. it can.

[0058]

As is apparent from the above description, according to the present invention, an analog RGB of another resolution mode which does not correspond to the actual physical dot configuration of the liquid crystal display portion of the coordinate input device with the liquid crystal display. Even when a signal is input, that is, when the resolution mode corresponding to the dot configuration is low or high, image display can be performed using a part of the screen of the liquid crystal display unit. Therefore, analog RGB with different resolution modes
It can be used as a coordinate input device with a liquid crystal display that can be connected to various types of computers that output signals.

In the structure in which a part of the screen of the liquid crystal display can be displayed as an image display area as described above, the image display area is moved to an arbitrary position on the screen by using a position indicator such as an electronic pen. be able to.

Further, in the above-mentioned image display area of a part of the liquid crystal display portion, it is possible to send accurate coordinate data on the screen to the computer in consideration of the offset amount at the position designated by the position indicator.

Further, in the structure in which the image display area is formed by utilizing a part of the liquid crystal display portion, the actual position of the position indicator and the position of the pointer can be accurately matched, and the image display can be performed. The inside and outside of the area can be accurately identified, and the valid area and invalid area of the input of the coordinate input device can be recognized.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a computer system to which an LCD tablet according to the present invention is applied.

FIG. 2 is a block diagram showing a detailed internal configuration of a coordinate input device with a liquid crystal display according to the present invention.

FIG. 3 is a diagram showing an example of a screen displayed on a liquid crystal display.

FIG. 4 is a block diagram showing a first functional example implemented by a CPU of a coordinate input device with a liquid crystal display.

FIG. 5 is a block diagram showing a second functional example realized by the CPU of the coordinate input device with a liquid crystal display.

FIG. 6 is a block diagram showing a third functional example implemented by the CPU of the coordinate input device with a liquid crystal display.

FIG. 7 is a flowchart showing an operation in an image moving mode.

FIG. 8 is a flowchart showing a coordinate detection operation in a normal mode.

[Explanation of symbols]

11 computer (personal computer) 12 CRT 13 analog RGB signal generator 14 output terminal 15 coordinate input device with liquid crystal display 27 liquid crystal display 28 CPU 31 screen 32, 32 'image display area 74 tablet circuit 76 switch 81 electronic pen

Claims (7)

[Claims] 1. A liquid crystal display comprising a liquid crystal display unit having a dot configuration corresponding to one resolution mode, and receiving an analog RGB signal supplied from a computer, and displaying on the liquid crystal display unit based on the analog RGB signal. A coordinate input device with a liquid crystal display, comprising: a display; and a coordinate input device superimposed on the liquid crystal display, a resolution mode determining means for determining a resolution mode of an input analog RGB signal, and the input analog device. When the resolution mode determination unit determines that the resolution mode of the RGB signal is different from the resolution mode of the dot configuration, the input is performed so that an image can be displayed using a part of the liquid crystal display unit. And a conversion means for converting an analog RGB signal. The liquid crystal display with the coordinate input device. 2. A liquid crystal having a liquid crystal display unit having a dot configuration corresponding to one resolution mode, inputting an analog RGB signal supplied from a computer, and displaying on the liquid crystal display unit based on the analog RGB signal. A coordinate input device with a liquid crystal display, comprising: a display; and a coordinate input device superimposed on the liquid crystal display, wherein a clock signal corresponding to each of a plurality of resolution modes lower than the resolution mode of the dot configuration is generated. Clock signal generating means, resolution mode determining means for determining whether or not the resolution mode of the input analog RGB signal is lower than the resolution mode of the dot configuration, and resolution mode of the input analog RGB signal. Is lower than the resolution mode of the dot configuration When said resolution mode determining means determines that the analog RGB
A selection unit that selects a clock signal corresponding to the resolution mode of the signal from the clock signal generation unit, and an image based on the input analog RGB signal in a part of the liquid crystal display unit using the selected clock signal. A coordinate input device with a liquid crystal display, comprising: display driving means for displaying. 3. A liquid crystal comprising a liquid crystal display unit having a dot configuration corresponding to one resolution mode, and receiving an analog RGB signal supplied from a computer, and displaying on the liquid crystal display unit based on the analog RGB signal. A coordinate input device with a liquid crystal display, comprising: a display; and a coordinate input device overlaid on the liquid crystal display, whether or not a resolution mode of the input analog RGB signal is higher than the resolution mode of the dot configuration. And a resolution mode determining unit that determines that the resolution mode of the input analog RGB signal is higher than the resolution mode of the dot configuration.
A coordinate input device with a liquid crystal display, comprising: a thinning-out means for thinning out a signal; and a display driving means for displaying an image on a part of the liquid crystal display section by using the thinned-out analog RGB signals. 4. The image display area set in a part of the liquid crystal display unit can be moved to an arbitrary position on the liquid crystal display unit by using a position indicator.
A coordinate input device with a liquid crystal display according to any one of 1. 5. An offset correction unit is provided for matching the display object of the position indicator and the position of the position indicator on the liquid crystal display unit when the image display area is moved using the position indicator. The coordinate input device with a liquid crystal display according to claim 4. 6. When an image is displayed on a part of the liquid crystal display unit, the resolution of an input analog RGB signal is
The coordinate input device with a liquid crystal display according to any one of claims 1 to 3, further comprising a correction unit that matches the resolutions of the coordinate input device. 7. The liquid crystal according to claim 1, further comprising means for discriminating an inner portion and an outer portion of the image display region which is a part of the liquid crystal display unit. Coordinate input device with display.