JPH03289619A - Display device - Google Patents

Abstract

PURPOSE:To comply with a request to support various display modes by using one of various display modes from a power-on point of time, determining a total control method in a ROM, and providing a control monitor part. CONSTITUTION:A ferroelectric liquid crystal display device (FLC) consists of the hardware constitutions of a display panel 2, display drivers 3 and 4, a display controller 8, a graphic controller 9, a host CPU 11, and a host bus 12, and ROMBIOS 13 wherein a total control monitor program is stored. Then the ROMBIOS 13 wherein necessary conditions are programmed in advance is put in charge of interface operation regarding the control and display of the computer main body 11 and FLC display, and a user can controls the display modes and scanning modes without having the detailed knowledge for, specially, FLC display control and driving. Consequently, the request to support various display modes is complied with.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for controlling a display device, and in particular, a method for controlling a display device, in which a scanning signal line and an information signal line are sandwiched between matrix electrodes, and a scanning signal and an information signal are respectively applied. The present invention relates to a control method for displaying video information using a liquid crystal display device driven by a liquid crystal display device, which has a memory property and whose driving conditions are temperature dependent. .

[Conventional technology]

Recently, displays such as liquid crystal display devices required for personal computers and workstations have become more and more popular year by year.
While larger screens and higher resolutions are becoming available, compatibility with conventional devices is also required. For example, in the case of an IBM PC/AT personal computer often used for boat fishing, the display mode for the image adapter is cGASEGA, VGA, 8514/8514/
There are over 10 display modes such as A, each with different resolution and number of colors that can be displayed.

As a product that can display many display modes on one display, NEC's Mul
tiSync If, MultiSync 3D,
There are 4D15D etc. For example, M ult i S
yn C4D and 5D supported V i d e
oMode (display mode) to Table
Shown in 1.

On the other hand, display devices with memory properties such as ferroelectric liquid crystal display devices are different from those used in conventional display devices such as CRT, 5TN-LCD (super twist liquid crystal display), and FDP (plasma display). The basic operating principle is different. Therefore, the present inventors have proposed a partial write scanning method that takes advantage of the memory properties proposed in U.S. Pat. The present invention is being attempted to be realized by a method of realizing ``low frame frequency driven ten-part write scanning'' for high resolution display in a display device with high resolution.

However, using this ferroelectric liquid crystal display (FLC),
In order to meet the above-mentioned demand for supporting various display modes, it is naturally impossible to achieve this using conventional methods due to the new driving principle. A complete set of essential features for users to use this ferroelectric liquid crystal display device connected to a computer to use one of the various display modes from the time the power is turned on, and to change the display mode as necessary. Control methods must be proposed.

Using a ferroelectric liquid crystal display device as an example, we present an overall configuration and its control method to support various display modes, especially for IBM PC/AT machines, and also to support a 1280x1024 high-definition mode. ,
A method for achieving the above object of the present invention will be clarified.

A ferroelectric liquid crystal display device, which is a typical example of a display device having memory properties, has a temperature dependence of driving conditions as typified by FIG. In this example, it is 7Hz at 10°C.

It shows a frame frequency of 10 Hz at 25 °C and 20 Hz at 40 °C (1024 scan lines,
24V drive voltage, when using KMT-408 manufactured by Chisso Japan). From this, if the temperature is 10° C. when the power is turned on, flicker can be prevented by using the 8-wire interlace in low frequency drive as proposed earlier. However, if the environmental temperature of the display rises after the start of operation, for example due to heating due to backlight lighting or forced use of an external heater, if the environmental temperature reaches 25 degrees Celsius, 4-line interlacing will be required. Flicker can be sufficiently prevented, and the phenomenon of division of the display screen during scroll display, for example, when displaying a moving image screen, which was the only drawback of 8-line interlacing, can be reduced. Also, even at the same temperature,
The driving method further changes depending on the display mode. For example, an FLC display with a display mode of 1024 scanning lines and 10 Hz in Tablel has a frame frequency of 480 scanning lines in VGA mode and a frame frequency of 20H.
z or more, normal (two-line) interlacing can sufficiently prevent flicker and further reduce screen division when displaying moving images. However, although there are conventional methods for determining the display mode, there is no method that can change the display scanning mode (interlaced, non-interlaced, etc.) in conjunction with the display environment temperature.

[Means (and effects) for solving the problem] In order to manufacture a computer equipped with an FLC display that satisfies the above requirements, a ROM (referred to as ROMBIO3) in which necessary requirements are programmed according to the product must be prepared in advance. is required. This ROM BIO5 actually controls the interface for controlling and displaying the computer and the FLC display, and the user especially needs to control the FLC display.
Display mode and scanning mode can be controlled without requiring detailed knowledge of C display control and driving.

That is, the present invention provides: a. A display panel in which scanning signal electrodes and information signal electrodes are arranged in a matrix, and a liquid crystal having memory properties and temperature dependence whose characteristics change depending on the environmental temperature is sandwiched between them. , b. Driving means for applying a scanning signal to the scanning signal electrode and applying an information signal to the information signal electrode; C6 Image information storage means for storing image information to be displayed on the display panel; d. Display on the display panel. display mode storage means for storing a display mode of image information to be displayed; e. scan mode storage means for storing a scan mode according to temperature information of the display panel; f. a driving condition control means for controlling, and g, reading image information to be displayed from the image information storage means, display mode stored in the display mode storage means, and a scanning mode stored in the scanning mode storage means; Accordingly, the display device is characterized by having display control means for controlling the drive condition control means and displaying information on the display panel.

〔Example〕

FIG. 1 shows a ferroelectric liquid crystal display device which is an embodiment of the present invention. Display panel 2 (1280x1024
Display drivers 3, 4, display unit controller 8, graphics controller 9 with VRAM 8 as image information storage memory, and IBM PC/AT.
12 shows the hardware configurations of the II and Ho5t Buses 12 and the ROMBIOS 13 that incorporates the entire control monitor program of the present invention.

(1) Function of signal line The function of the signal line provided between the Ho5t CPU11 and the graphics controller 9 in FIG. 1 will be described below.

Ho5t Bus: Standard interface hardware bus specified by IBM, called ATBus for IBM PC/AT machines.

The functions of each signal line provided between the FLC display unit controller 8 and the graphics controller 9 in FIG. 1 will be explained below.

1) PDO~7: Data path. 8-bit bidirectional. Data transfer rate 10 MHz/8 bit.

2) CLK: Transfer lock. 20MHz 03
) AH/DL Identification signal between two-part motion information and video information.

High level when driving information. picture When it comes to information, the Lo level.

4) IHloL: Data path input/output identification signal. From the perspective of the graphics controller, when PDO~7 is in input mode, it is Hi level. Lo level when in output mode.

5) INT: Interrupt signal from the display device side to the graphics controller.

6) FLG: Data output permission signal from the display device side to the graphics controller. High level when output is enabled.

7) Hsync: Horizontal synchronization signal. Data acceptance permission signal from the display device side to the graphics controller.

8) Vsync: Vertical synchronization signal. Synchronization signal for each display screen.

(2) Basic operation A function defined in the ROM BIO 313 is called from the video information generating side, that is, from the Ho5t CPU 11 side, according to a predetermined calling rule, and sometimes parameters necessary for realizing the function are passed to the graphics controller 9. On the ROM BIO 313 side, when called in a normal procedure, it is translated by the GCPU (graphics control central operator) 14 or directly works on the display controller 9 to realize the requested function.

Below, we will explain the specific translation or direct content and operation overview.

The graphics controller 9 transfers drive information and video information to the FLC display unit using bidirectional data buses PDO-7. However, since driving information and video information are transferred through the same transmission path, it is necessary to distinguish between the two types of information.

The signal for this identification is AH/DL. AH/DL
When the signal is at Hi level, it indicates that the information on PDO~7 is "drive information", and when it is at LO level,
This indicates that it is "video information."

FLC display unit controller 8 is PDO
The drive information is extracted from the video signal with drive information transferred as 7 to 7, and processing is performed based on the drive information. On the other hand, the video information is transferred to the shift register 6 on the information electrode drive circuit side and sent based on the lock.

Furthermore, in this embodiment, since the drive display of the FLC display and the generation of drive information and video information in the graphics controller 9 are performed asynchronously, it is necessary to synchronize the devices when transferring display information. The signals that control this synchronization are Hsync and vsync.
Vsync is generated in the FLC display unit controller 8 every 1 horizontal scanning period, and Vsync is generated every 1 vertical scanning period during refresh, and sent to the graphics controller 9 side. The graphics controller 9 constantly monitors these 5sync signals, and when Vsync is high
Display information when i level and Hsync is Lo level (
At other times, after one transfer of display information is completed, it waits until the next transfer permission signal arrives.

Figure 3 shows F from the graphics controller 9 side.
This is a timing chart of basic communication when sending display information to the controller 8 side of the LC display unit 1, and its operation will be explained.

Graphics controller 9 has Hsync set to L.
O level (and INT=Hi&Vsync=Hi&IH
/○L=L (must be Lo) is detected, the AH/DL signal is immediately set to Hi level and transfer of display information is started. The controller 8 of the FLC display unit sets Hsync to Hi level during the display information transfer period. After completing a series of processes based on the palm-read drive information, the controller 8 of the FLC display 1 sets Hsync to Lo level again and prepares to receive the next display information.

In Figure 4, the graphics controller 9 side is FL.
This is a timing chart of basic communication when reading display information from the controller 8 side of the C display unit 1, and its operation will be explained.

First, the graphics controller 9 uses the controller 8 of the FLC display unit l as drive information.
The "information read request data" agreed upon in advance with the controller 8 is sent to the controller 8 of the display unit 1 at timings AO to A15 in FIG. 4, and the data input mode is set by setting the ll10L signal to Hi. At this time, the data buses PDO-7 are in a high impedance state (Z) when viewed from the graphics controller 9 side. When the controller 8 of the FLC display unit 1 recognizes the "information read request data", it
After confirming that the 0L line is at the H level, information is placed on the data bus PDO~7 and the FLG signal is set at the H level. Graphics controller 9 is FL
When it detects that the G line becomes Hi, it reads the data on the data bus PDO~7 at that time, and
Stored in the CPU 14.

(3) Communication operation when displaying an image When displaying an image on the display, display information is sent from the graphics controller 9 side to the display side, which is the same as the communication shown in FIG. 3 above. At this time,
The driving information is scanning line address information, which is placed at the position AO-A15 in FIG. 3 and transferred to the display controller 8.

Looking at the details in more detail, the scanning line address information is extracted by the controller 8 of the FLC display unit 1, inputted to the scanning line electrode drive circuit side decoder 7 in accordance with the timing of driving the specified scanning line, Selects the specified scan line of the display. On the other hand, the video information is transferred to the information electrode drive circuit side shift register 6, and shifted in units of 8 pixels at a transfer lock (CLK). When the shift for one scanning line in the horizontal direction is completed in the shift register 6, the video information for 1280 pixels is transferred to the line memory 5 attached thereto and stored for one horizontal scanning period. Then, after one predetermined horizontal scanning period has passed and the writing operation to the display panel 2 is completed, the controller 8 of the display unit sets Hsync to the LO level again.
Receives display information for the next scan line.

By repeating these series of communication operations, writing operations and partial writing operations on the display panel screen are performed.

(4) Operation when setting the display mode - When setting the host side - Setting and changing the display mode for the display device is basically
This is based on a request from the o5t side, and basically complies with the timing chart shown in FIG. The details are described below.

■Graphics controller 9 is Ho5tCPU
When there is a display mode change request from the 11 side, the drive information part (when the AH/DL line is Hi level, that is, the AO-A15 in FIG. 5) when transferring display information to the controller 8 of the display unit 1. ``Display mode change request data'' is placed at the timing of ``Display mode change request data''.

■After the controller 8 of the display unit 1 recognizes the prearranged "display mode change request data", it sets the Hsync line to the LO level.

■The graphics controller 9 then inputs the "display mode number" as drive information to AO-A1 in Figure 5.
At timing 5, the signal is sent to the controller 8 of the display unit 1, and the IH10L signal is set to Hi level, thereby switching the data buses PDO to 7 to the input mode.

■The controller 8 of the display unit l receives the "display mode number" and determines the driving conditions of the display panel according to the display mode, the relationship between the number of physical pixels and the number of logical pixels, and the number of colors and gradations. or determine the size of the effective display screen and the outer frame of the inner display area of the display screen, and determine the relationship between the color and the number of gradations or both of the outer frame. In order to determine the format and/or timing of information transfer from the image information storage unit to the display device, and to confirm whether communication has been carried out normally, the receiver sends the received "display mode number" to the IH10L line. After confirming that F is at Hi level, put it on data bus PDO~7
Set the LG signal to Hi level.

■After confirming that the FLG line has become Hi level, the graphics controller 9 connects the data bus PDO to 7.
G
Stored in the CPU 14.

- The GCPU 14 compares the received data with the previously transferred "display mode number", and after confirmation sets the IH10L signal to LO level.

■Controller 8 of display unit l is IH1
After confirming that the 0L line has become Lo level, turn Hsy
Set the nc line to LO level and wait for the next display information.

■After confirming that the Hsync line has become Lo level, the graphics controller 9 selects the normal scanning line address +
Send the video information, and if there is an error, send the "display mode conversion request data" again and start over from ■.

With the above procedure, it is possible to change the display mode and control the drive of the display panel according to each display mode.

(5) Operation when setting the display mode When setting from the display side - For example, the graphics controller 9 and the controller 8 of the display unit 1 are configured with separate power supplies, and the controller 8 side of the display unit 1 is powered by graphics controller 9
If it is entered after the (Host side) has started up, it is not possible to know in what display mode the graphics controller 9 is already operating on the controller 8 side of the display unit 1. In such a case, the controller 8 of the display unit 1 sends an INT signal to the graphics controller 9 to request the display mode to be set. When the graphics controller 9 receives the INT signal from the display unit controller 8, it checks the FLG line and recognizes that it is a display mode setting request if it is at Lo level. After that, the display mode is set in the same procedure as (4) Operation when setting the display mode - when setting from the host side.

(6) Operation Ho when scanning mode is set according to temperature information
In order for the 5t side to know the temperature information of the display unit 1 and set the scanning mode accordingly, the graphics controller 9 side shown in Fig.
A method is used in which temperature information is read from the controller 8 side of the LC display unit 1 as part of the display information. The operation will be explained in more detail below.

■The graphics controller 9 writes "temperature information read request data" in the drive information part (when the AH/DL line is at Hi level) when transferring display information to the display device.
The data buses PDO to PDO7 can be switched to the input mode by placing the ll10L signal at Hi level.

■The controller 8 of the display unit 1 receives the prearranged "temperature information read request data"
After confirming that the ll10L line is at Hi level, "temperature data" is placed on data buses PDO to 7, and the FLG signal is set at Hi level.

■Graphics controller 9 confirms that the FLG line has become Hi level, then data node PDO~
7 is outputted is stored in the GCPU 14.

(2) The GCPU 14 sets the scanning mode of the display panel based on the received "temperature data."

It is also possible for the display device to issue a request to set or change the scanning mode to the main device in response to changes in the environmental temperature of the display panel. In this case, the display device first sends an INT signal to the graphics controller 9, as in the case of display mode setting. When the graphics controller 9 receives the INT signal from the display device side, it checks the FLG line and recognizes that it is a request to read temperature information if it is at Hi level. After that, temperature information reading and scanning mode setting operations are performed in the same procedure as when a request is made from the main device side.

Also, Table 2 (Figure 8) shows the 1° Alphanumeric Mode 2° Graph in IBM mode.
Shows the adapter name, resolution, color and number of gradations, and FLC display drive information supported by ics Mode. The expression rb/pJ in Table 2 determines the color and number of gradations in the output information for the input information, and is the video data format developed in the video information storage memory VRAM10 in Figure 1, and is 1 pixel (
represents the number of bits representing the binary representation of the amount of color and gradation information for one logical pixel). Expression rra in Table2
tio] represents the relationship between the number of physical pixels and the number of logical pixels, and this relationship is shown in FIG. In the FLC display of this embodiment, one pixel unit is a physical pixel having two different area ratios. Therefore, when ratio=1, the minimum logical pixel configuration is one, and the number of gray levels that can be expressed is four. (The FLC display is basically a binary display, and one of the methods for realizing multi-value display, that is, gradation display, by the FLC display is to combine two physical pixels with different area ratios into one.)
A pixel-based method has already been proposed. ) rat
When io=2, one logical pixel consists of four physical pixels and two minimum pixel units, and the number of gradations becomes eight. Similarly rati
When o=4, one logical pixel has 8 physical pixels and 4 minimum pixel units, and 16 gradations are possible.

FIG. 9 shows the relationship between the environmental temperature of the display panel and the scanning mode. The scanning mode differs depending on the above-mentioned "ratioJ," and even at the same environmental temperature, the larger the value of "ratio", the smaller the interlacing width in the scanning mode (=improving the display quality of the moving image).

The scanning mode shown in FIG. 9 is based on the rratioJ and the environmental temperature of the display panel to reduce the screen splitting phenomenon when displaying a video screen and to reduce flicker depending on the frame frequency.
The settings are optimized from a prevention perspective.

Further, FIG. 10 shows the specifications of each scanning mode (scanning order of the display panel). The scanning procedure for each scanning mode will be briefly explained below.

(A) Interlace scanning - Figure 10 (A): All scan lines are selected sequentially from the top to the bottom of the display screen without skipping over them. This scanning method has the best display quality of moving image screens.

(E) 32 interlaced scan - Figure 10 (B): Scanning lines are skipped and selected every 32nd. l frame is 3
It consists of two fields, and the selection order of each field is random.

(C) Tips Scanning - Figure 10 (C): Divide all scanning lines into a plurality of blocks and select the blocks one after another. Two interlaced scans are performed within each block, but when comparing one block and the next block in units of blocks, the scanning start positions are selected to be different. An l frame consists of two fields. In Table 4, all 1024 scanning lines are sequentially selected into 16 blocks every 64 lines.

(D) Fips scanning - Figure 10 (D): Tips
Similar to scanning, all scanning lines are divided into a plurality of blocks, and the blocks are sequentially selected. Four interlaced scans are performed within each block, but when comparing one block and the next block on a block-by-block basis, the scanning start positions are selected so that they differ. An l frame consists of four fields. In the example of Table 4, the total 1024 scanning lines are 128
For each book, 8 blocks are selected in block order.

〔Effect of the invention〕

As described above, we have developed a total control method that is essential for using one of the various display modes from the time the power is turned on, and changing the display mode as necessary.
By having a part of the control monitor that allows for further changes according to a certain procedure from the Ho5t side in some cases, it is possible to control drive information that could not be realized with conventional methods due to the new drive principle. Using a ferroelectric liquid crystal display device that requires
It has become possible to meet the demand for supporting various display modes such as SYNC.

Note that the present invention is not limited to ferroelectric liquid crystals, and the display device has scanning signal lines and information signal lines sandwiched between matrix electrodes, is driven by applying scanning signals and information signals respectively, and has memory properties. , is obviously useful when the driving conditions have temperature dependence.

[Brief explanation of the drawing]

FIG. 1 shows a display device, main unit, and ROM according to the present invention.
Overall configuration diagram including BIO5. FIG. 2 is a diagram showing the temperature dependence of frame frequency, which is one of the driving conditions of the FLC display unit. FIG. 3 is a timing chart showing communication operations when driving information and video information are sent from the main device side graphics controller to the display device. FIG. 4 is a timing chart showing communication operations when the graphics controller on the main unit side reads drive information of the display device. FIG. 5 is a timing chart showing communication operations when the graphics controller on the main device side switches the display mode of the display device. FIG. 6 is a diagram showing the relationship between physical pixels and logical pixels in the display section of the ferroelectric liquid crystal display device according to the present invention. In Figure 7, Table is a product name M u I manufactured by NEC that has a typical display mode switching function in CRT.
t A diagram showing the schematic functions of 1Sync4D and 5D. Figure 8 shows Tab! e2 is a display mode of the FLC display system according to the present invention.
Function overview and FL when supporting RT graphics mode
FIG. 3 is a diagram showing part of C display driving conditions. FIG. 9 is a diagram showing the relationship between the environmental temperature of the display panel and the scanning mode for each rratioJ. FIGS. 10(A) to 10(D) are diagrams showing specifications of scanning modes (scanning order). Wyr+c 1 Laff1 vi-tot-do゛-Ili<rat-+c-do)+-1
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Claims (2)

[Claims] (1) a. A display panel in which scanning signal electrodes and information signal electrodes are arranged in a matrix, and a liquid crystal having memory properties and temperature dependence whose characteristics change depending on the environmental temperature is sandwiched between them; b. , driving means for applying a scanning signal to the scanning signal electrode and applying an information signal to the information signal electrode; c. image information storage means for storing image information to be displayed on the display panel; d. display on the display panel. display mode storage means for storing a display mode of image information to be displayed; e. scanning mode storage means for storing a scanning mode according to temperature information of the display panel; f. controlling driving conditions of the display panel according to environmental temperature; and (g) reading out image information to be displayed from the image information storage means, according to the display mode stored in the display mode storage means and the scanning mode stored in the scanning mode storage means. A display device comprising display control means for controlling the drive condition control means and displaying on the display panel. (2) The display device according to claim 1, wherein the liquid crystal is a ferroelectric liquid crystal.