JPS59140492A - Liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an active matrix type liquid crystal display device.

In recent years, advances in dot matrix display technology using active panels with active elements built into silicon or glass substrates have made it possible to manufacture liquid crystal panels with a large number of pixels. It consisted of a switching transistor provided in each pixel and a capacitor for holding display data. Therefore, the driving method is to periodically scan one pixel by point-sequential or line-sequential driving.
Display data is updated using nine methods. Even when the image does not change for a certain period of time, it must always scan at a certain cycle and refresh the display data, so it consumes a lot of power and cannot be applied to equipment that requires low power consumption. It was difficult.

In order to solve this problem, Japanese Patent Application No. 57-■ (Organization A17)
Equivalent to 592. ) within each pixel as shown in the patent
An active panel with a built-in MOS static memory has been realized, and with this method, there is no need to supply display data from outside the active panel when the image is still, making it possible to significantly reduce power consumption. In this method, the display data held in each pixel is binary information of lighting or non-lighting, that is, \ or 1, so it is not suitable for displays that include brightness and dark contrast such as TV images, but 1 It is possible to provide an optimal means for usage patterns in which relatively the same display of characters, figures, etc. continues for a long time.

However, even if an active panel with built-in CMQB static memory as described above is used to reduce power consumption, it is generally difficult to apply the active panel to a portable microelectronic device such as an electronic wristwatch due to the following. It's a good idea to tweet something like that.

It was difficult to put it into practical use.

(1) In order to realize an electronic wristwatch using an active panel, it is optimal to use a one-chip microcomputer that has a counting function and an active panel control function due to cost and implementation constraints. As the oscillation source for generating the system clock of this one-chip microcombi/user, a crystal resonator with an oscillation frequency of 52 KHz is often used due to power consumption constraints.

A frequency of 8KH2 or less is often used as a system clock, and therefore, the instruction execution time usually takes 9122 μs or more per instruction. In addition, many internal data processing systems are of the 4-pinto type. Even if tf6
To update the 4x48 pixel panel screen,
5072/4 = 768 transfer processing times are required. Therefore, even if data transfer of 4 pints can be executed with one command, it takes 94.6 m5ec to complete writing the entire screen. However, in actual software, processing routines for X and Y addresses, character-1-item searches, etc. need to be processed using micro 10 grams, and it is normal for the display rewriting time to reach nearly one set. be.

As mentioned above, the one-chip microcomputers used in electronic watches are much slower than general-purpose microprocessors with clock frequencies of several megahertz, and are required to update the active panel screen. The drawback is that it takes too much time to transfer the display data of the large blind.

(2) When using the active panel as a display terminal for a small vehicle device other than an electronic wristwatch, it is necessary to display relatively high-speed videos such as animations, even when general-purpose microprosen-t can be used. If there is, the same problem as in case (1) has occurred. This is because the speed of moving images is limited by the data transfer time from the microprocessor to the active panel.

The present invention has been made in view of this point.

An object of the present invention is to reduce the display update time of an active panel when a microcomputer drives an active panel that has a static memory built into each pixel, and to make the active panel into an ultra-compact device such as an electronic wristwatch. It is an object of the present invention to provide a liquid crystal display device which enables the application of the liquid crystal display device and is equipped with a means for increasing the display speed of moving images when used as a display terminal for small equipment. .

In order to selectively update the display data of only a part of the display 11411 of the liquid crystal active panel, the present invention allocates display characters to each fixed display area.
It has a mechanism that determines the display area that requires display updating using the microprogram in the Microphone III core computer.
Furthermore, the present invention is characterized in that a data register address counter and a scanning line address counter are built into the microcomputer or active panel as hardware.

Hereinafter, details of embodiments of the present invention will be described based on the drawings.

Figure 11 shows the basic configuration of the active panel. 1 is a donmatrix array consisting of 64 X lines and 48 X lines.

A 0M0S static memory is arranged at each intersection of the X line and the X line, and the drive waveform of the first pixel is controlled by the information in that memory. 2 is a data register with a built-in Y driver, which is a matrix array. 48 of
Connected to the book's X line. 3 is an 8-bit data line.

Provides the λ power signal for the data register. 4 is a 3-pit Y address line and determines the address of the delta register. 5 is an X scanning line decoder with a built-in X driver, which is connected to 64 scanning lines. 6 is a 6-bit X address signal. 7 is a write signal for the data register, and 8/fi is a write signal for the pixel memory on the scanning line. 9 is a common driver for each rIhJ
- Supply 52 Hz rectangular formation to x. 1o is the 52 Hz 1g line from the microcomputer.

To operate itself, a microcomputer generates a signal as shown in Figure 2, which activates the active panel shown in Figure 1. The (1)//i data signal in Figures 1 and 2 is supplied from the 8-pin cheater line microcomputer. (2) is the Y address signal, which is the Y address of the L cheater register, Y1 to Y.
Select one out of 6.

(3) is the data register write signal, and during the period when the signal is at H level, the data signal is written to the portion of the data register selected by the Y address. (4)
This is an address signal for selecting one of the 64 X lines, which are ti scanning lines. (5) is a pixel memory write signal, and while it is at H level, the contents of the 48-pin data register are written to the 48 pixel memories on the scanning line selected by the X address. In rare cases, the display on that scan line is updated. The period indicated by T is the display update time for one scan 111tj, and the update time for all the fili11 pages is 64×T. By adopting this driving method, it is not necessary to update the entire screen, but only a portion of the screen can be updated by setting the X address.

It is possible to improve processing speed. Conventional liquid crystal display devices that do not have static memory in their pixels have a mechanism called video RAM inside the microcomputer that holds one screen's worth of display data, and a shift register to constantly refresh the display data. I had to do some scanning. However, in this device, which has static memory built into each pixel, there is no need to transfer data for areas of the screen that continue to display the same image; By making a limited display update based on this judgment, the display update time can be significantly reduced.

A specific example will be explained using Fig. 5. In this embodiment, the X line is divided into 810 VR areas of 8 lines each, and the display configuration is such that display patterns (numbers and letters) are allocated to each area, so the area where the display needs to be updated is used. The display can be updated by selecting the appropriate information using the software. Therefore, in order to change the display twice, for example, to increment the data, it is only necessary to transfer data in the area of /ri8×48 dots, and the data transfer time is reduced to 1%.

In order to determine the display area, the software takes the configuration shown in FIG. 114. 11 is the starting point of the display routine;
The clock is reset by a 1-second interrupt. 12 is a 1-second increment processing routine that calls up the morning, afternoon, hour, minute, and second data stored in the microcomputer's RAM and adds 1 to the 1-second value.

If a carry occurs in the sexagesimal system, the higher digits are carried to the next island, and the result is rewritten into the RAM. 16 is a part that reads and outputs the address of the ROM in which the font of numbers or letters is stored. 14 is 1
Based on the result of step 2, this part determines which area's display needs to be updated, and has the role of controlling the subsequent display routine. 15 has a function of assigning an initial value 1 to the X address and performs initialization. 16 outputs 8-bit data (character-font) to the data line. 17 generates a data launch write counter and writes data to the part of the data register specified by the X address. 18 adds 1 to the X address and returns to 16 (#), repeats the processes 16 to 18 six times, and sends data for one scanning line to the data register. 19
is a conditional branch to proceed to step 20 and subsequent steps when Y7 address exceeds 8. 2o sets the X address of the set meal line of the part that needs updating based on 14, and
Output to address line. 21 is 4 of the cheat register
In order to transfer the 8-focus data to the pixel memory on a specific scanning line specified by the X address, a pixel memory filling counter is generated. Reference numeral 22 denotes a condition branch for determining whether or not the operation of 21 is to be completed for the necessary remaining portion of the scanning line. 26 is the end point, after which the microcomputer is in a halt state and starts up again at the 5th one-second interlude.

As shown above, in the non-implemented example, a system is adopted in which the display characters are allocated to each of the eight display areas, and the microprogram in the microphone CRJ viewer is used to determine the area in which display updates are required. Therefore, even with a relatively low-speed microcomputer, the transfer time for one character is approximately 50 m5ec, making it possible to apply this to the Kai electronic wristwatch.

Next, an embodiment of the spear 2 in which the scanning line on the same X line of the activate panel is divided into two in order to further enhance the effect of shortening the display update time will be described with reference to FIGS. 1'-5. 1.2, 5, and 4.7 have the same configuration as the embodiment 1, but the scanning line decoder and X driver are 24.2.
The counters of the one-pixel registers placed in the upper and lower positions shown in 5 are also controlled by separate signal lines as shown in 26 and 27. 28II'iX address fM is supplied to both 24 and 25.

In this embodiment, a software function similar to that of the first embodiment (
By using υ, the time required to update the display can be further reduced to close to A, and when combined with the first embodiment, the time can be reduced to close to lA6, <;
Sufficient speed for displaying the clock can be ensured.

Next, an example of the spear 5 will be described using a diagram of the fang 6.

29, 50, and 51 are seven flops and function as a dedicated branch circuit. 5, 2 are input clocks, 55, 54
．． 55 is connected to the data register X address line. The circuit shown in Figure 16 has the function of an octal counter and can be built into any microcomputer or active panel to calculate the X address. In the embodiments of 171 and 2, the counting of X addresses was realized by software, but in this embodiment, by realizing this function by hardware, it is possible to shorten the software processing time. . To operate this, y2: Every time data transfer is completed, a strobe signal is generated by the microcomputer, and this is input to the arrow 6 (Figure 52), and the X address is set to 1.
Increase from 8 to 8 in 1 step increments.

The method of incorporating the address counter of this embodiment need not be limited to use for counting X addresses for data registers, and a similar method can also be used as a counter for X addresses for scanning line decoders.

In this method, the number of microprogram steps in one display routine can be significantly reduced, and as a result, the display update time can be shortened. In comparison, it can be applied to small electronic devices that require high-speed video display.

As described above, the present invention has the advantage of being able to shorten the update time for one display in a liquid crystal display device using an active panel in which each pixel includes a stubby memory. In devices such as electronic wristwatches that use relatively slow microcomputers, the conventional method that does not use the present invention takes nearly one second to update the display, and it is difficult to display not only a stopwatch but also hours, minutes, and seconds. , it was difficult to make an active panel do this. By using the present invention, it is possible to apply it to electronic wristwatches, and furthermore, in devices using general-purpose micro-pro sensors, it is possible to display video much faster than before. , its practical effects are great.

[Brief explanation of the drawing]

】・Figure 1 is a configuration diagram of an active panel that has static memory built into each pixel, which is a component of this bag. )・Figure 2 is a timing chart of the input waveform for driving the active panel shown in Figure 1. Figure 3' shows a liquid crystal display device according to the present invention. FIG. 3 is a configuration diagram of a display screen when a clock is displayed. FIG. 214 is a flowchart of the software of the microcomputer which is a component of the present invention. Figure 115 is a configuration diagram of the active panel divided into two parts, upper and lower. Figure 6 is a circuit diagram of an address counter that counts the Y address of the data register. 1...Active panel, 2...Data register. 5...Data signal, 4...X address signal. 5...Scanning line decoder, 6...X address signal. 7...Data register write signal. 8... Pixel memory write signal, 9... Common driver, 10... Common signal. Above Figure 1 (1) DI D2 [)3 D4 D
5 D6 p11 Figure 2 Section 3 1 Section 1' ] 1 Figure 6 1

Claims (1)

[Scope of Claims] (1) A static memory that holds binary information such as lighting or non-lighting as a display form for each pixel, that is, a note or 1, and driving of the pixel electrode by the information in the static memory. In a liquid crystal display device consisting of a donmatrix display liquid crystal active panel consisting of a control circuit that controls a waveform, a data register and a scanning line decoder in one peripheral part, and a microcomputer that controls the liquid crystal active panel, a liquid crystal active two panel is used. A liquid crystal display device comprising means for selectively updating display data of only a portion of a display screen. (2. A liquid crystal display device characterized in that an address counter for counting the address of a data register of an active panel is built into the active panel or microcomputer as claimed in claim 1. (3) Claims A liquid crystal display device characterized in that an address counter for counting the addresses of scanning lines of an active panel is built into an active panel or a microcomputer mounted on a WQ.