JPH06250627A - Display system - Google Patents

Abstract

PURPOSE:To display a picture without failure on each display device by means of one host computer and one display controller when an internal synchronization type display device and an external synchronization type display device are coexisting. CONSTITUTION:In the display system consisting of coexisting display devices 55 having single or plural generating means for internal synchronizing signal or a waveform generating means for driving a liquid crystal and a single or plural display devices 58 displaying by external synchronization, this system is provided with either the selecting means 70, 73, for selecting either a synchronizing signal S1 supplied from the generating means for internal synchronizing signal or from the waveform generating means for driving a liquid crystal or a timing signal S2 for generating the waveform for driving the liquid crystal, or generating means 70, 73 calculating the period of the signal S1 or the signal S2 and generating a new signal and a synchronizing signal supplying means supplying a selected or generated signal S4 or S5 to the display device displaying by external synchronization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display system in which a display device for displaying in internal synchronization and a display device for displaying in external synchronization are mixed, and more particularly, a ferroelectric liquid crystal display device is used as these display devices. The present invention relates to a display system suitable for application when used.

[0002]

2. Description of the Related Art A CRT (Cathode Ray Tube) has been used as an application using a plurality of display devices. In recent years, TN (Twisted Nema)
tic), STN (Super Twisted Ne)
Liquid crystal display devices such as
It has come to be used for a personal computer or the like. A ferroelectric liquid crystal FLC (Ferroelectric Liquid) disclosed in US Pat. No. 4,367,924 proposed by Clark et al.
Crystal) is recognized as a high-contrast and high-resolution display device because it has characteristics such as a memory property and a high-speed response without installing a non-linear element.

External synchronizing means or internal synchronizing means is used as a synchronizing means for supplying image data from each display control device to the various display devices to the display device, depending on the characteristics of the display device. For example, if the CRT is externally synchronized,
In many cases, the STN display device and the like perform display by external synchronization using the cumulative response to the electric field. Under such circumstances, a method of FLC is known in which a temperature detecting means is provided in order to compensate the temperature characteristic of the liquid crystal itself and the reception cycle of image data is controlled. Therefore, when displaying the FLC display device under such control, means for internal synchronization is required. Such control means is described in Japanese Patent Laid-Open No. 63-65425 proposed by Hagino et al.

Conventionally, when displaying on a plurality of FLC display devices which have a means for detecting the external condition and which perform display in internal synchronization, display is performed using the same number of display control devices. For example, if there are two display devices, the display devices 20, 21 are displayed using the same number of display control devices installed in the host computers 10, 11 as shown in FIG.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances, and there is at least one display device that performs display in internal synchronization, and a synchronization signal and / or a liquid crystal drive from the display device. When there are multiple display devices that are supplied with waveform generation timing and perform display in external synchronization, the first drive method that performs the same display on each display device using one display control device, internal synchronization When there is at least one display device that performs display, and when there is a plurality of display devices that perform synchronization signal and / or liquid crystal drive waveform generation timing from the display device and perform display in external synchronization, A second drive method that enables different display for each display device by using the display control device, one synchronization signal generation device having an external condition detection means, and one image data device. A third drive method for performing the same display on each display device when there are a plurality of display devices that perform display in external synchronization using the supply means, and a single synchronization signal generator having external condition detection means And when there are a plurality of display devices that perform display in synchronization with each other by using a plurality of image data supply means, any one of the fourth driving methods capable of performing different displays for each display device. It is an object to provide a driving method or a display system capable of driving the driving method as needed. That is, an attempt is made to solve the problem of compensation of external conditions and the driving problem that occurs when the display synchronization is established.

Specifically, display on a plurality of display devices can be performed by one external condition detecting means and one synchronizing signal generating means, or one external condition detecting means and one liquid crystal drive waveform. It is an object of the present invention to provide a display system that can be executed by means of supplying generation timing. When the latter is applied to the display system, it can be realized with a relatively easy configuration.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a single or a plurality of internal synchronizing signal generating means, for example, a display device for displaying by the internal synchronization and a display by a single or a plurality of external synchronizing signals are displayed. In a system with mixed display devices, a. First means (synchronization signal selection means or liquid crystal drive waveform generation timing selection means) for selecting one of the synchronization signals (and / or liquid crystal drive waveform generation timing) supplied from the mixed internal synchronization signal generation means, and b ． The period (cycle) of the sync signal (and / or liquid crystal drive waveform generation timing) supplied from the display device that performs display with mixed internal synchronization is measured, and the synchronization signal (and / or liquid crystal drive waveform generation) of a new period is calculated by calculation. At least one of second means (synchronization signal generation means or liquid crystal drive waveform generation timing generation means) for generating timing; and c. It is characterized in that it has a third means (a synchronization signal supply means or a liquid crystal drive waveform generation timing supply means) for supplying the synchronization signal to a display device which displays by an external synchronization signal.

In one embodiment of the present invention, the first means compares the periods in which the synchronization signals (and / or the liquid crystal drive waveform generation timing) of the mixed internal synchronization signal generation means are supplied, and the synchronization is performed. A signal (and / or liquid crystal drive waveform generation timing) is selected.

[0009]

In the present invention, when a plurality of display devices are simultaneously driven, the ambient environment of each device is often the same,
Also, paying attention to the fact that there is a margin in the driving condition of the liquid crystal, simultaneous display of a plurality of units is performed without failure by using one detecting unit for external conditions and one synchronizing signal generating unit. For example,
In a ferroelectric liquid crystal display device, a method is known in which a horizontal display timing corresponding to a response speed that changes according to temperature information is supplied to a display control device as a synchronization signal. The ferroelectric liquid crystal has the qualitative property of the horizontal scanning time (proportional to the response speed of the liquid crystal) with respect to the temperature as shown in FIG. It can be seen from FIG. 4 that the displayable area has an allowable range with respect to temperature changes. Therefore, if the temperature environment is substantially the same, it is possible to simultaneously display a plurality of display devices by using the temperature information from one display device as a period change of the synchronization signal to another display device. However, as shown in FIG. 14, when a plurality of display devices 20 and 21 which perform display in internal synchronization are included, a predetermined number of external condition detection means 22 and 23 and respective synchronization signals S11 and S12 are used. Means 26 for selecting signals are required.

Conventionally, when a plurality of devices are simultaneously displayed, the same number of external condition detecting means and the same number of display control devices as the display devices are provided. On the other hand, in the present invention, in the case of the display of the minimum configuration, the display system has one display control device, one synchronization signal generator or one internal synchronization type display device having one external condition detecting means, and a plurality of external synchronization type display devices. A display system can be constructed with a display device. Further, when a plurality of display control devices are provided, different display can be performed on the screen of the display device to which each image data is supplied. Therefore, according to the present invention, the display system having a multi-screen configuration requiring simultaneous display of a plurality of display devices, the information display system for transportation, the image information demonstration display system, or the evaluation display system is simplified, It can be used in a limited space and expands the application of the display system.

[0011]

EXAMPLES The present invention will now be described in detail based on examples. The description will be given in the following procedure.

(1) Description of the internal synchronous display device (2) Description of the external synchronous display device (2.1) Description of the external synchronous display device that performs display by a horizontal synchronous signal (2.2) Liquid crystal drive waveform Description of external synchronous display device that performs display according to generation timing (3) Description of display system in which internal synchronous display device and external synchronous display device are mixed (3.1) One internal synchronous display device and one Description of a display system in which external synchronous display devices are mixed (3.2) Description of a display system in which a plurality of internal synchronous display devices and external synchronous display devices are mixed (4) Modified example

(1) Description of Internal Synchronous Display Device FIG. 7 shows a conventional display system in which one host computer 30 equipped with a display control device displays on one ferroelectric liquid crystal display device 20. Show. Regarding the flow of image data, the workstation 40 first writes the updated image data to a video memory (not shown) provided in the display control device 32 in response to a request from the drawing primitive. Next, the display control device 32 is supplied with a horizontal synchronizing signal from the display controller 21 incorporated in the display device 20, and supplies the scanning line address and the image data to the display controller 21 at the timing shown in FIG. The period (cycle) of the horizontal synchronizing signal is determined by the detection value of the temperature sensor 22 installed on the surface of the glass plate sandwiching the liquid crystal element. The image data transferred to the display controller 21 is sorted into odd-numbered and even-numbered image data and supplied to the segment drivers 23 and 24. Then, the segment drivers 23 and 24
An appropriate voltage is applied to the segment electrode side of the matrix structure electrode of the liquid crystal display element 26. This voltage is
The liquid crystal element is driven by causing a potential difference from the voltage applied from the driver 25 to the common electrode. By the series of data control described above, the display of the display device 20 which performs the display in the internal synchronization is enabled.

FIG. 8 shows an internal synchronous display device 12 according to the present invention. In FIG. 8, the display control device (not shown) is
A horizontal synchronizing signal is supplied from the display controller 13 incorporated in the display device 12, and the scanning line address and the image data are supplied to the display controller 13 at the timing shown in FIG. The period of the horizontal synchronizing signal is
It is determined by the detection value of the temperature sensor 22 installed on the surface of the glass plate holding the liquid crystal element. The image data transferred to the display controller 13 is sorted into odd-numbered pixel data and even-numbered pixel data and supplied to the segment drivers 23 and 24. Then, the segment drivers 23 and 24 apply an appropriate voltage to the segment electrode side of the matrix structure electrode of the liquid crystal display element 26.
This voltage causes a potential difference from the voltage applied from the common driver 25 to the common electrode, and drives the liquid crystal element. The display of the internal synchronization type display device is enabled by the series of data control.

The structure of the display controller 13 will be described in more detail. Image information timing control unit 10
0 has a function of controlling image data at a transfer rate and timing suitable for the segment drivers 23 and 24. The controlled image data is stored in the image information storage controller 10
In 3 the data is stored in the 1-line memory, is read out at a predetermined cycle, and is supplied to the odd-even-numbered segment drivers 23 and 24. Then, the drive control unit 102 supplies the liquid crystal drive waveform generation timing (writing timing of one line) for generating the drive waveform to the common driver 25 and the segment drivers 23 and 24. The first clock generator 104 is a clock signal that serves as a reference for the liquid crystal drive waveform generation timing. The second clock generation unit 105
An operation clock of the controller 13 and a reference clock of the image information transfer timing control unit 100. The operation procedure control unit 101, which is responsible for the main control of these functions, is programmed to control the operation procedure of the display controller 13. Further, in this display system, the liquid crystal drive waveform generation timing can be supplied from the image information transfer timing control unit 100 to the outside.

FIG. 9 is a timing chart for the display controller 13 shown in FIG. 8 to generate the horizontal synchronizing signal and the liquid crystal driving waveform. Each waveform will be described with reference to FIGS. 8 and 9. First, the operation procedure control unit 101 issues an instruction to convert the information from the temperature sensor 22 to a digital value from the analog / digital converter, and sets a value in the programmable counter 106 according to the conversion value. The programmable counter 106 starts counting clocks output from the second clock generator 105 when the horizontal synchronizing signal HSYNC goes low. The counter 106 repeats counting up to a value set by the operation procedure control unit 101, and generates a timer signal TIMER each time. The timer signal TIMER is supplied to the drive controller 10
2 is supplied. The signal is a liquid crystal drive waveform generation timing signal whose drive waveform is switched at each rising edge. Further, since this signal is used in the display system of the present invention, it is supplied to the outside as a liquid crystal drive waveform generation timing signal.

The drive control unit 102 controls the segment waveform level values SWFD0, 1 and the common waveform level value CWFD.
0 and 1 are supplied to the segment drivers 23 and 24 and the common driver 25, respectively. The values in the waveform are the numbers shown in the following drive voltage correspondence table, and the corresponding voltage is supplied to each driver.

[0018]

[Table 1]

The signal HT becomes low level at the first fall of the timer signal TIMER after the horizontal synchronization signal HSYNC becomes low level, and the next timer signal TI
It is set high again at the falling edge of MER.

SWFD0,1, CWFD0,1, T
The segment drivers 23 and 24 and the common driver 25 are controlled by the IMER and HT signals.

The supply of the liquid crystal drive waveforms of the drivers 23, 24 and 25 to the liquid crystal element is started when the timer signal TIMER rises during the period when the HT signal is low level. The voltage level of the liquid crystal drive waveform at that time is determined by the values of SWFD0,1 and CWFD0,1 at the rising of each timer signal TIMER. In FIG. 9, the drive waveform shows one horizontal synchronization period.

The above operation is performed by the horizontal synchronizing signal HSYNC.
Is repeated every time it becomes low level, and display on the internal synchronization type display device becomes possible.

(2) Description of External Synchronous Display Device (2.1) Description of External Synchronous Display Device for Displaying with Horizontal Sync Signal FIG. 10 shows an external synchronous display device which receives a horizontal sync signal from the outside for display. The structure of the mold display device 14 is shown. The difference from the internal synchronization type liquid crystal display device 12 of FIG.
It is not necessary to install the temperature sensor 22 shown in FIG. In addition, the image information transfer timing control unit 111 does not generate the liquid crystal drive waveform generation timing signal. Therefore, the liquid crystal drive waveform generation timing signal is generated by the quadruple multiplication unit 110 in the display controller 15.

FIG. 11 shows the operation of the quadruple multiplication control unit 110. In the case of this embodiment, the segment and common drive waveforms have a drive waveform of 4 slots per horizontal synchronization period. For this reason, the horizontal synchronizing signal is multiplied by a signal of four cycles by the quadruple multiplication control unit 110 and supplied to the image information transfer timing control unit 111 and the drive control unit 102 as a liquid crystal drive waveform generation timing signal. The multiplier circuit is composed of a normal phase lock loop and a counter. The drive waveform of the liquid crystal is generated from the above signal in the same procedure as that of the internal synchronous display device.

(2.2) Description of External Synchronous Display Device for Displaying at Liquid Crystal Drive Waveform Generation Timing FIG. 12 shows an external synchronous display device 16 for supplying a liquid crystal drive waveform generation timing signal from the outside for display. .
The difference from the internal synchronization type liquid crystal display device 12 of FIG. 8 is that the temperature sensor 22 shown in FIG. 8 is not required to be installed in the liquid crystal display element 26, and the image information transfer timing control unit 111 uses a horizontal synchronization signal (liquid crystal drive). Start signal) is not generated. Therefore, the LCD drive start signal is
It is generated by the drive start control unit 120 in the controller 17.

FIG. 13 shows the operation of the drive start controller 120. In the case of this embodiment, the segment and common drive waveforms are composed of one set of four slots. For this reason, the liquid crystal drive start signal is obtained by counting the liquid crystal drive waveform generation timing with a counter and generating a pulse when the count reaches four. The signal is supplied to the image information transfer timing control unit 111 and the drive control unit 102 as a liquid crystal drive waveform generation start timing signal. The drive waveform of the liquid crystal is generated from the above signal in the same procedure as that of the internal synchronous display device.

(3) Description of display system in which internal synchronous display device and external synchronous display device are mixed (3.1) Description of display system in which one internal synchronous display device and external synchronous display device are mixed A display method when an internal synchronous display device and an external display device are mixed will be described. Signal lines S1 to S6 in FIG.
Reference numeral 4 is a horizontal synchronizing signal, S2 and S5 are liquid crystal drive waveform generation timings, and S3 and S6 are image data. Here, other display control signals are not shown. The horizontal synchronizing signals S1 and S4 and the liquid crystal drive waveform generation timings S2 and S
Either 5 may be used. However, the horizontal sync signal S
When only 1 and S4 are supplied, the liquid crystal drive waveform as shown in FIG. 11 is generated as a function of the display controller equipped in the external synchronous liquid crystal display device as described in (2), so that the horizontal synchronous period The quadrupling circuit 110 is required. Further, liquid crystal drive waveform generation timings S2 and S5
Only by itself, a circuit for detecting the start of the horizontal scanning period as shown as the drive start control unit 120 is required. However, both circuits can be realized by a combination of currently known ordinary circuits. Based on the above technique, both signals are illustrated in this embodiment.

A display system in which one internal synchronous display device and one external synchronous display device are mixed will be described below with reference to FIG.

A. When the horizontal synchronization signal S1 is supplied from the internal synchronization type display device 55 The horizontal synchronization signal S supplied from the internal synchronization type display device 55
1 is supplied to the video timing circuit 52 and the external synchronization type display device 58 via the synchronization signal selection circuit 70. The video timing circuit 52 uses the horizontal synchronizing signal S
Image data S3 and S6 in synchronization with the display device 55
And 58. The internal synchronous display device 55 performs display with the liquid crystal drive waveform generated from the supplied image data S3 and the internal liquid crystal drive waveform generation timing. The external synchronous display device 58 also generates the liquid crystal drive waveform generation timing by multiplying the supplied horizontal synchronous signal S4 by four. Then, the display device 58 displays with the liquid crystal drive waveform generated using the liquid crystal drive waveform generation timing signal and the supplied image data S6. FIG. 3 shows the timing of the display signals S1 to S6. b. When the liquid crystal drive waveform generation timing signal S2 is supplied from the internal synchronization type display device 55: The liquid crystal drive waveform generation timing signal selection circuit 73 counts the liquid crystal drive waveform generation timing signal S2 supplied from the internal synchronization type display device 55. Therefore, the synchronization signal SYN
Generate C. The synchronizing signal is a horizontal synchronizing signal HSYNC.
Is supplied to the video timing circuit 52. The video timing circuit 52 supplies the image data S3 and S6 to the display devices 55 and 58 in synchronization with the horizontal synchronizing signal. The internal synchronous display device 55 uses the supplied image data S3 and internal liquid crystal drive waveform generation timing S2.
Display is performed by the liquid crystal drive waveform generated from. The external synchronous display device 58 also counts the liquid crystal drive waveform generation timing signal to generate a liquid crystal drive start timing. Then, the display device 58 displays with the liquid crystal drive waveform generated by using the liquid crystal drive waveform generation timing signal S5, the liquid crystal drive start timing signal and the supplied image data S6.

(3.2) Description of Display System in which Multiple Internal Synchronous Display Devices and External Synchronous Display Devices are Mixed Conventionally, a plurality of internal synchronous display devices 20 and 21 are conventionally provided as shown in FIG. In the case of simultaneous display, a plurality of display control devices (host computer 10,
11 equipment) was used. Here, by utilizing the fact that there is a margin in the physical properties of the liquid crystal and the driving conditions, a plurality of simultaneous display in which a plurality of internal synchronous display devices and external synchronous display devices coexist in one display control device under substantially the same environment. It is proposed that it will be possible by using it.

Referring to FIG. 1, a computer 40, such as a workstation, is shown. The display control device 50 of the present invention is provided on the mother board of the computer 40 or on the expansion BUS. Ferroelectric liquid crystal display device (internal synchronous display device 55, external synchronous display device 5
8) is connected to the display controller 50 using a plurality of conductive lines. The display controller 50 is a workstation 40.
Has a set of video memory 51 (FIG. 2) for storing image data requested by a request from a client or a drawing primitive. The video timing circuit 52 provided in the display controller 50 shown in FIG.
The image data read from the image memory 51 is supplied to the display devices 55 and 58 through the current amplifier 71 at the timing shown in FIG. 5 in synchronization with the horizontal synchronizing signal S1 sent from the display device 55. Here, consider a case where a plurality of internal synchronous display devices 55 are connected to the display control device 50. In this case, a plurality of horizontal synchronizing signals S1 and /
Alternatively, it is necessary to select a predetermined signal from the plurality of liquid crystal drive waveform generation timing signals S2. The signal period selection unit 53 is composed of a selection switch or a signal period counting circuit and a count value comparison circuit, and plays the role.

The synchronization signal selection circuit 70 includes: a. A function of selecting a plurality of horizontal synchronization signals by a selection switch, b. A function of individually counting the periods of a plurality of horizontal synchronizing signals and comparing the counted values to automatically select a predetermined signal, and c. It has the function of individually counting the periods of multiple horizontal synchronization signals and calculating the measured values with each other to generate the horizontal synchronization signal of a new period. The physical properties of the liquid crystal used in the display device and the alignment state of the display element The function is selected by. The selected horizontal synchronizing signal S4 is supplied to the video timing circuit 52 and the external synchronizing display device 58. 71,7 in the figure
Reference numeral 2 is a normal current buffer IC that relays the current of the image data and the control signal.

The liquid crystal drive waveform generation timing signal selection circuit 73 includes: a. A function of selecting a plurality of liquid crystal drive waveform generation timing signals with a selection switch, and b. It has a function of individually counting the periods of multiple LCD drive waveform generation timings and automatically selecting a predetermined signal by comparing the counted values. The physical properties of the liquid crystal used in the display device and the alignment state of the display element The function is selected by. Further, the selection circuit 73 generates a read synchronizing signal of the image data S3 and S6 from the selected liquid crystal drive waveform generation timing signal S5 by using a counting circuit. The synchronizing signal is supplied to the video timing circuit 52, and the liquid crystal drive waveform generation timing signal S5 is supplied to the external synchronizing type display device 58. In the figure, 71 and 72 are normal current buffer ICs that relay the currents of image data and control signals. The image data S3 and S6 supplied to the display devices 55 and 58 are converted by the display controller 13 (FIG. 8), 15 (FIG. 10) or 17 (FIG. 12) into the segment drivers 23 and 2 as drive waveforms as shown in FIG.
4 is supplied.

For example, one horizontal synchronizing period shown in FIG.
Temperature sensor 2 provided on the glass surface of the liquid crystal panel 26
The display controller 13 (FIG. 8) determines the temperature information from 2 (FIG. 8).

Further, the display control device 50 of FIG. 2 determines from the plurality of horizontal synchronizing signals S1 or the plurality of liquid crystal drive waveform generation timing signals S2 supplied when a plurality of the internal synchronizing type display devices 55 are present. It has a signal period selection unit 53 for performing signal selection. FIG. 6 shows liquid crystal drive waveforms when there are a plurality of internal synchronous display devices (No. 1 and No. 2 display devices). With reference to FIG. 1
Display and No. In the two-display, a difference of T1 occurs in the liquid crystal driving time depending on the environmental temperature.

The case where a plurality of horizontal synchronizing signals S1 are supplied to the display controller will be described below in detail. In order to read the image data S3 from the image memory 51 in synchronization with the horizontal synchronizing signal without failure, it is necessary to select the longest signal of the plurality of horizontal synchronizing signals. Therefore, the display control device 50 selects the longest signal from the plurality of horizontal synchronization signals S1 by the synchronization signal selection circuit 70, reads the image data S3 from the image memory 51, and supplies it to the display device. In FIG. The image data S3 is supplied to the display device in synchronization with the period of the horizontal synchronizing signal supplied by one display device. Then, during the adjustment time T1, a common voltage (VC) is generated in the display device and supplied to the segment driver and the common driver. When these drive voltages are the common voltage (VC), the liquid crystal is not driven. Under substantially the same ambient environment, there is no adjustment time T1 (FIG. 6) or within one time slot. When the liquid crystal drive waveform generation timing signal S2 is supplied from a plurality of internal synchronous display devices 55, the longest signal is selected by the liquid crystal drive waveform generation timing signal selection circuit 73 and generated by the counting circuit. The sync signal is provided to the video timing circuit 52.
By the above control, the image data S3 can be read and displayed. Therefore, by providing the signal period selection circuit 53 (FIG. 2), it is possible to simultaneously display a plurality of internal synchronous display devices. The display on the external synchronization type display device 58 is the same as the case of (3, 1).

(4) Modification 1. The external condition detecting means includes not only the temperature environment but also detecting means such as light intensity, humidity, pressure or magnetic field.

2. Although the horizontal synchronizing signal is used as the synchronizing signal in the present embodiment, the vertical synchronizing signal may be compared and selected and the image data may be read at the horizontal synchronizing timing corresponding thereto.

3. This display system is provided with a multiplication circuit in a control device that detects an external condition independent of the display device, and constitutes a device that can generate a liquid crystal drive waveform generation timing.
It is also possible to use with a plurality of the external synchronization type display devices and display them simultaneously.

[0040]

As described above, in the display system of the present invention, when all the display devices have substantially the same operating environment, one host computer and one display control device are used, so that one or more display devices can be used. It is possible to display an image on the internal synchronous display device having the external condition detecting means and the external synchronous display device having no external condition detecting means without failure. Therefore, it is possible to construct a low-cost simultaneous display system with a simple configuration. Such a substantially stable operating environment is intended for demonstration of a display device, simultaneous display on each vehicle of a railway train, or environmental test of the display device. Therefore, simultaneous display on a plurality of display devices is possible in various fields by using this display system.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a display system including a display control device and a display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of the display control device of FIG. 1 in more detail.

FIG. 3 is a timing diagram of the display signals shown in FIG.

FIG. 4 is a diagram showing a temperature characteristic of a display device using a ferroelectric liquid crystal.

FIG. 5 is a timing chart of signals used in an internal synchronous display device.

FIG. 6 is a diagram of drive waveforms supplied to a segment driver and a common driver by a display controller included in an internal synchronous display device in the system of FIG.

FIG. 7 is a diagram of a conventional internal synchronization type display device and a display control system for driving the display device.

FIG. 8 is a diagram of an internal synchronization type display device capable of supplying a liquid crystal drive waveform generation timing signal.

9 is a diagram of internal operation timing of the display device shown in FIG.

FIG. 10 is a diagram of an external synchronization type display device which is supplied with a horizontal synchronization signal and is capable of displaying.

11 is a diagram showing a conversion operation of a quadruple multiplication control unit in the display controller equipped in the display device shown in FIG.

FIG. 12 is a diagram of an external synchronous display device which is supplied with a liquid crystal drive waveform generation timing signal and is capable of displaying.

13 is a diagram showing a conversion operation of a drive start control unit in the display controller equipped in the display device shown in FIG.

FIG. 14 is an example in which a plurality of conventional internal synchronous display devices are displayed by one display control device.

FIG. 15 is a diagram showing a configuration of a display system using a conventional display control device and a plurality of conventional internal synchronous display devices.

[Explanation of symbols]

10, 11: Computer equipped with conventional display control device, 12: Internal synchronous liquid crystal display device capable of supplying liquid crystal drive waveform generation timing to the outside, 13: Display capable of supplying liquid crystal drive waveform generation timing to the outside・
Controller, 14: External synchronization type liquid crystal display device which is supplied with horizontal synchronization signal for display, 15: Display controller which is supplied with horizontal synchronization signal and can generate liquid crystal drive timing signal, 16: Liquid crystal drive waveform generation timing signal External synchronization type liquid crystal display device supplied and displaying, 17: Display controller capable of generating liquid crystal drive timing signal by being supplied with liquid crystal drive waveform generation timing signal, 20, 21: Conventional internal synchronization type display device, 22: Temperature sensor, 23, 24: segment driver, 25: common driver, 26: display controller,
30: Computer equipped with conventional display control device, 3
2: Conventional display control device, 40: Computer, 50:
Display control device according to the present invention, 51: video memory, 5
2: video timing circuit, 53: signal period selection unit,
55: Internal display type display device according to the present invention, 56: Ferroelectric liquid crystal display element, 57: Temperature sensor, 58: External synchronization type display device according to the present invention, 70: Synchronization signal selection circuit, 7
1, 72: current buffer, 73: liquid crystal drive waveform generation timing signal selection circuit, 100: image information transfer timing control unit, 101: operation procedure control unit, 102: drive control unit, 103: image information storage control unit, 104: Clock generation unit 1, 105: Clock generation unit 2, 110: 4 multiplication control unit, 111: Image information transfer timing control unit, 11
2: operation procedure control unit, 120: drive start control unit, S1,
S4: horizontal sync signal, S2, S5: liquid crystal drive waveform generation timing signal, S3, S6: image data, T1: adjustment time, VC: common voltage, V1 to V5: liquid crystal drive voltage.

Claims (28)

[Claims] A display system in which a single or a plurality of internal synchronization signal generating means and a display device for performing a display in a single or a plurality of external synchronizations are mixed, wherein a synchronization signal supplied from the internal synchronization signal generating means is provided. A display system comprising: a synchronization signal selection means for selecting any one of the above and a synchronization signal supply means for supplying the selected synchronization signal to a display device for displaying according to the external synchronization signal. A display system in which a single or a plurality of internal synchronization signal generating means and a display device for performing a display in a single or a plurality of external synchronizations are mixed, and a cycle of a synchronization signal supplied from the internal synchronization signal generating means. And a sync signal supply means for supplying the sync signal of the new cycle to a display device for displaying by the external sync signal. Display system characterized by. 3. The display system according to claim 1, wherein the internal synchronization signal generating means is incorporated in a display device that performs display in internal synchronization. 04. The display device which performs display by the internal synchronization has means for detecting an external condition and cycle control means for controlling the cycle of the internal synchronization signal based on the detection result of the external condition. Display system described. 5. The display system according to claim 1, wherein the display device that performs display by the external synchronization has means for generating a drive waveform of liquid crystal by being supplied with a synchronization signal. 6. The display system according to claim 5, wherein the display device for displaying in the external synchronization does not use an external condition detecting means. 07. The synchronizing signal selecting means compares the periods of a plurality of synchronizing signals supplied from a plurality of synchronizing signal generating means, and selects one of the plurality of synchronizing signals based on the comparison result. The display system according to claim 1. 8. The display system according to claim 7, wherein the sync signal selection means selects a sync signal having a longest cycle from among the plurality of sync signals. 9. The display system according to claim 7, wherein the synchronization signal selection means selects a synchronization signal having a shortest cycle from the plurality of synchronization signals. 10. The synchronization signal generation means measures the cycles of a plurality of synchronization signals supplied from the plurality of synchronization signal generation means, and generates a synchronization signal having an average cycle of the cycles. The display system according to claim 2. 11. A display device for displaying in accordance with the external synchronization, means for detecting an external condition, and another display device based on a detection result of the external condition and a synchronization signal supplied from the synchronization signal supply means. The display system according to claim 1 or 2, further comprising means for generating separate sync signals. 12. The display device for displaying according to the external synchronization, displays according to the synchronization signal supplied by the synchronization signal supply means.
Display system according to any one of. 13. A display system in which one or a plurality of liquid crystal drive waveform generating means and one or a plurality of display devices for performing display in synchronization are mixed, wherein a liquid crystal drive waveform generating timing in the liquid crystal drive waveform generating means is included. A liquid crystal drive waveform generation timing selection means for selecting any one of the above, and a drive waveform generation means for generating a drive waveform for displaying on the liquid crystal by the display device that performs display in the external synchronization based on the drive waveform generation timing. A display system characterized by: 14. A display system in which a single or a plurality of liquid crystal drive waveform generating means and a single or a plurality of display devices for performing display in synchronization are mixed, and the liquid crystal drive in the single or a plurality of liquid crystal drive waveform generating means. A liquid crystal drive waveform generation timing selection means for selecting any one of the waveform generation timings, and a liquid crystal drive waveform generation timing supply means for transmitting the liquid crystal drive waveform generation timing to a display device for displaying by the external synchronization signal. A display system characterized by: 15. The display system according to claim 13, wherein the liquid crystal drive waveform generating means is built in a display device that performs display in internal synchronization. 16. The display system according to claim 13, wherein the liquid crystal drive waveform generation timing selection means and the drive waveform generation means are provided in the display device for displaying in synchronization with the external synchronization. 17. The liquid crystal drive waveform generation timing selection means compares the periods of a plurality of liquid crystal drive waveform generation timings supplied from the plurality of liquid crystal drive waveform generation means, and based on the comparison result, the plurality of liquid crystal drive waveform generation timings. The display system according to claim 13, wherein any one of the waveform generation timings is selected. 18. The display system according to claim 15, wherein the display device that performs display in the internal synchronization has means for supplying a liquid crystal drive waveform generation timing signal generated in the display device to the outside. 19. The display device for displaying in the internal synchronization has means for detecting an external condition and cycle control means for controlling the cycle of the liquid crystal drive waveform generation timing signal based on the detection result of the external condition. Item 16. The display system according to Item 15. 20. The display device for displaying in external synchronization has means for generating a liquid crystal drive waveform by being supplied with a liquid crystal drive waveform generation timing signal.
The display system according to 3 or 14. 21. The display device according to claim 20, wherein the display device that performs display in the external synchronization does not use an external condition detecting unit. 22. The liquid crystal drive waveform generation timing selection means selects one having a liquid crystal drive waveform generation cycle that is longer than a plurality of liquid crystal drive waveform generation timing cycles. Display system. 23. The liquid crystal drive waveform generation timing selection means selects one having a liquid crystal drive waveform generation cycle that is the shortest of a plurality of liquid crystal drive waveform generation timing cycles. Display system. 24. A display device for displaying in synchronization with the external device comprises means for detecting an external condition, a detection result of the external condition, and a liquid crystal drive waveform generation timing supplied from the liquid crystal drive waveform generation timing selection means. 15. The display system according to claim 13, further comprising means for generating a liquid crystal drive waveform generation timing signal which is separated from other display devices. 25. The display device which performs display by the external synchronization performs display in synchronization with the liquid crystal drive waveform generation timing supplied by the liquid crystal drive waveform generation timing supply means. Display system according to any one of. 26. The display system according to any one of claims 1 to 11 and 13 to 24, wherein the same image data is supplied to all of the plurality of display devices to perform the same display. 27. The display device according to claim 1, wherein different image data is supplied to each of the plurality of display devices to perform individual display.
And the display system according to any one of 13 to 24. 28. The liquid crystal display device uses a liquid crystal exhibiting ferroelectricity.
The display system according to any one of to 24.