JPH09243993A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to execute display of an arbitrary display capacity (display duty) without being limited by the output number of low drivers by independently forming field signals. SOLUTION: The number of simultaneous selection is specified to L(1<L<=n) lines and (i) is defined to indicate the field number of 1<i<n. The field period from the i-th scanning to the (i+1)tn scanning is farmed as the value which indicates the one field period obtd. by holding the results of the measurement from a scanning start signal to a scanning start signal and dividing the results of the holding by L. A clock counter 1 measures how many SCAN-CKs exist in the period from a START signal to a START signal. An arithmetic and logic unit 2 takes in the results of the measurement and divide the same by the number L of the simultaneously selection lines. The results are held in a latch 3 and are compared with the value of the successively updated clock counter 1. A CA signal is outputted at every period divided by the value held in the latch 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device which is a display portion of an information processing device such as a word processor, a personal computer, a portable information device, a portable telephone, and an electronic device.

[0002]

2. Description of the Related Art A conventional liquid crystal device using a multiple line simultaneous selection driving method (IHAT method and MLS method) using an orthogonal function is shown in a timing chart of FIG.
As shown in the schematic view of the liquid crystal device. The basic technology is the IHAT method document (TN, RUCKMONGATHAN: "A generaliz
ed addressing technique for rms responding matrix "
1988 INTERNATIONAL DISPLAY RESEARCH CONFERENCE, P8
0). In order to perform distributed driving, a period determined by the number of output signals of the row driver divided by the number of selections L from the scan start signal (START) constitutes a ring counter (loop by shift register) that is initialized by the scan start signal and is cascade-connected. Each row driver recognizes the selection time and the field number (the number indicating the number of the field). In addition, the column driver inputs the field signal that loops the ring counter to recognize the field number. (A row means a common electrode to which a selection signal is applied, and a column means a signal electrode to which a signal corresponding to screen data is applied. The column driver and the row driver drive the corresponding electrodes, respectively.)

[0003]

In the above-mentioned prior art, since the field period determined by the number of output signals of the scanning driver IC divided by the number of selections L is fixed, it is impossible to display at any display duty. . In the case of FIG. 9, 1/6 duty cannot be realized, and there is no choice but to choose 1/8 or 1/4 duty. There was a limitation that the display duty was an integer multiple of the number of driver outputs. (Conventionally, the leading row driver Y1 depends on the output CA2 of the final Y driver Y2, as can be seen from FIG. 9.) Therefore, the present invention solves such a problem, and its purpose is arbitrary. It is an object of the present invention to provide a liquid crystal device using the IHAT method and the MLS method, which enables the display of the display capacity (display duty) of 1 above without being limited by the number of outputs of the row driver.

[0004]

According to a first aspect of the present invention, in a liquid crystal device driven by a multiple line selection driving method using an orthogonal function, the number of simultaneous selections is L lines when distributed driving is performed to disperse selection signals. As (1 <L ≦
n) and i are field numbers (scan numbers) of 1 <i <n, and the scan switching cycle (field cycle) from the i-th scan to the i + 1-th scan is started from the scan start signal. It is characterized in that the result of measuring the period up to the signal is held, and the held result is divided by L to create a value indicating one field period.

With this configuration, the invention according to claim 1 can display with an arbitrary display duty.

The invention described in claim 2 is characterized in that the field cycle of claim 1 can be set from an external terminal.

With this configuration, the invention according to claim 2 can display with an arbitrary display duty.

The invention described in claim 3 is characterized in that the field cycle of claim 1 can be set by writing it in a latch.

With this configuration, the invention according to claim 3 can display with an arbitrary display duty.

The invention according to claim 4 is characterized in that the liquid crystal device according to claim 1 is mounted as a display device.

Therefore, the invention according to claim 4 is the IHA.
While utilizing the features of the T method and the MLS method, a liquid crystal device with an arbitrary display duty and display pixel number can be selected, and the degree of freedom in product design is improved.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

[Embodiment 1] FIG. 5 shows an embodiment of the present invention. The number of display pixels is set to 8 × 6 for easy understanding of the description. (It does not limit the actual display dots. Actually, various numbers of pixels such as 640 × 200 called CGA and 640 × 480 called VGA are conceivable.) The signal line shows only the signal serving as a point. The column driver X has 8 column outputs. Row driver Y
1 and Y2 have outputs of 4 lines. Number of simultaneous selections L
= 2 lines. The number of simultaneous selections is not limited to 2 lines because all lines can be selected as already described in the claims. Conventionally, in the case of a Y driver having an output of 4 lines, 1/8 duty or 1
The row drivers Y1 and Y2 could only be used with / 4 duty. Therefore, in order to display 1/2 duty, 1/6 duty, etc., it is necessary to newly design a row driver. However, in the present invention, it is possible to cope with an arbitrary (integer multiple of the selection number L) display duty by creating the field signal independently. FIG. 4 shows the driving state of the present invention in a timing chart. Scan start signal (STA
RT) is at the "H" level every time one screen is scanned. The scan clock (SCN_CK) is controlled by a number corresponding to the display duty. In this embodiment, SCN_C
The falling edge of K is used. ROW1 to 6 indicate that the "L" level is the non-selected output,
The "H" level indicates that the output is selected. Since this timing chart is just an example, various combinations are actually conceivable. For example, the scanning clock is a power of 2 (64, 256, 512, ...) For the reason of providing a non-selected period or the convenience of logic design.
To output extra. Further, a detailed description will be given with reference to FIG. Since the number of simultaneous selections is 2, two scans (field number 1 and field number 2) are performed simultaneously on two lines. In FIG. 4, the first field period F1 and F2
That is, there is a second field period.
Since F1 and F2 have an orthogonal relationship, (1,1) and (1,-
A vector combination such as 1) is selected. (Details are explained in the literature of the IHAT method.) FIG. 5 is also explained in parallel in order to visualize the state of selection. The hatched portion in FIG. 5 shows the row electrode in the selected state. FIG.
The time in the selected state indicated by is present in F1 (field number 1) and F2 (field number 2), respectively, since the ROW3 and 4 are "H" timing in FIG. Here, in the present invention, Y1 has a circuit block 6 as shown in FIG. 1 and self-forms a field period. Therefore, the scan cycle from the first field to the second field can be completed without depending on the final row driver Y2 connected in cascade. The block diagram of FIG. 1 will be described. The circuit block 6 has the following functions. The clock counter 1 measures how many SCAN_CK exist in the period from the START signal to the START signal. Next, the calculator 2 takes in the measurement result of the clock counter 1 and divides it by the number L of simultaneously selected lines. Then, the result is held in the latch 3 and is compared with the value of the clock counter 1 that is being updated, and a CA signal (indicating the switching of the field period) is output for each period divided by the value held in the latch 3. The logic is designed to be done. Although it is shown as a digital circuit for the sake of clarity, it may be an analog circuit. The circuit shown here is merely an example, and the scope of implementation is the content described in the claims. The CA signal self-formed in this way enables driving at an arbitrary display duty by shifting the lines connected in cascade. The freedom of design was improved without being limited by the number of outputs of the row driver, and the optimum driving conditions could be selected. In addition, since the row driver can be used in common for many models, it has the excellent merit that it can be standardized and cost can be reduced. [Embodiment 2] FIG. 2 shows another embodiment of the present invention. The block diagram of FIG. 2 will be described. The circuit block 6 has the following functions. The CA signal is output every period divided by the value held in the latch 3 by performing a comparison operation with the setting data 5 held by the external terminal held in the latch 3 and the clock counter 1 value being updated. The logic is built into. The CA self-formed in this way can be driven at an arbitrary display duty by shifting the lines connected in cascade.

[Embodiment 3] There is an embodiment as shown in FIG.
The block diagram of FIG. 3 will be described. The circuit block 6 has the following functions. The value input by the DATA signal is written in the latch 3 by the WRITE signal, the data held in the latch 3 is compared with the value of the clock counter 1 being updated, and the result is divided by the value held in the latch 3. The logic is configured so that the CA signal is output for each period. This makes it easy to change the duty with software.

[Embodiment 4] Although the circuit block 6 described so far is mounted in the row driver Y1 in FIG. 5, it may be mounted in the column driver X as in the embodiment of the present invention shown in FIG. Good.

[Embodiment 5] As in the embodiment of the present invention shown in FIG. 7, a row driver and a column driver may be combined independently with a liquid crystal controller, a liquid crystal power supply IC, or the like.

[Embodiment 6] FIG. 8 shows an electronic apparatus in which the liquid crystal device of the present invention is mounted as a display device. There is no limitation on the number of outputs from the row driver. Therefore, the palmtop PC 7 can be designed with an optimal size by selecting any number of pixels. Similarly, the portable information device 8 can realize a flexible screen display according to the application by utilizing the features of the IHAT method and the MLS method.

[0018]

As described above, any display duty can be flexibly selected. Therefore, it is not limited to the limited display size (an integer multiple of the number of output terminals of the driver), and the optimum drive condition can be selected.
It became possible to apply the low voltage drive of the method and the frame response elimination of the MLS method to a wide range of products. In addition, the common use of row drivers enabled standardization and cost reduction.

[Brief description of drawings]

FIG. 1 is a block diagram of a CA signal generation circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram of a CA signal generation circuit according to another embodiment of the present invention.

FIG. 3 is a block diagram of a CA signal generation circuit according to still another embodiment of the present invention.

FIG. 4 is a timing chart of a 1/6 duty embodiment of the present invention.

FIG. 5 is a schematic diagram of a 1/6 duty embodiment of the present invention.

FIG. 6 is an embodiment having a circuit block in which a column driver creates a CA signal at 1/6 duty according to the present invention.

FIG. 7 is an embodiment having a circuit block in which a liquid crystal controller or a power supply IC creates a CA signal at 1/6 duty of the present invention.

FIG. 8 is a perspective view of an embodiment in which the present invention is applied to an electronic device such as a palmtop PC or a portable information device.

FIG. 9: 1/8 by conventional IHAT method and MLS method
It is the figure which showed the liquid crystal device in duty.

FIG. 10: 1 / according to the conventional IHAT method and MLS method
It is a timing chart in 8 duty.

[Explanation of symbols]

 1. Clock counter 2. Operation unit 3. Latch 4. Comparator 5. Setting data 6. CA forming circuit block 7. Palmtop PC 8. Portable information equipment

Claims (4)

[Claims] 1. In a liquid crystal device driven by a multiple line simultaneous selection driving method using an orthogonal function, when distributed driving for dispersing selection signals (hereinafter abbreviated as MLS method), the number of simultaneous selections is set to L lines ( 1 <L ≦
n: n is the number of time divisions, i is a field number (scan number) of 1 <i <n, and a scan switching cycle from the i-th scan to the i + 1-th scan (hereinafter referred to as a field cycle) The liquid crystal device is characterized in that a result obtained by measuring a period from a scanning start signal to a scanning start signal is held, and the holding result is divided by L to create a value indicating one field period. 2. A liquid crystal device, wherein the field cycle of claim 1 can be set from an external terminal. 3. A liquid crystal device, wherein the field cycle of claim 1 can be set by writing it in a latch. 4. An electronic apparatus comprising the liquid crystal device according to claim 1 as a display device.