JPH0934411A - Image display device and liquid crystal display controller - Google Patents

Abstract

(57) [Summary] [Structure] An image obtained from the resolution ratio setting means is provided with a resolution ratio setting means and an arithmetic unit for performing calculation between adjacent pixels in the LCD controller for transferring image data to the display device. According to the ratio of the resolution of the data and the display device, when the display data is transferred to the display device, the operation device performs an operation between adjacent pixels to enlarge / reduce the image. [Effect] Since the image can be enlarged / reduced without redrawing in the display memory, the image data of the number of pixels different from the resolution of the liquid crystal display is displayed on the display without changing the drawing software. It can be displayed together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly to an image display device capable of obtaining a good image when the display resolution is switched in a display device using a flat panel such as liquid crystal.

[0002]

2. Description of the Related Art As a display of an image display device of a personal computer (personal computer), a desktop type is generally a CRT and a portable type is a liquid crystal. In such a display device, an LSI for display control called a CRT controller in a device using a CRT and an LCD controller in a device using a liquid crystal is mounted. As the LCD controller, there is CL-GD6205 manufactured by Cirrus Logic Inc. in the United States. The display resolution of personal computers at the beginning of popularization was 640 x 480 pixels, but then 800 x 600
It is possible to display pixels and 1024 × 768 pixels. In order to operate the conventional software even with such a high resolution, it is necessary to display at a low resolution. Therefore, in the device using the CRT, the display resolution can be switched according to the purpose. CRT
Can always be displayed on the entire screen even if the resolution is switched. That is, when a CRT capable of displaying 1024 × 768 pixels displays 640 × 480 pixels, an enlarged image is displayed.

[0003]

However, in a device using liquid crystal, even if the resolution is switched, it is not possible to always display on the entire screen like a CRT. This is because the CRT display does not have fixed pixel spacing on the cathode ray tube, whereas the liquid crystal display has fixed pixel spacing. For example, when 640 × 480 pixels are displayed on a liquid crystal display capable of displaying 800 × 600, an empty area is generated as shown in FIG. This empty area can be eliminated by enlarging / reducing the data in the display memory by redrawing so as to match the resolution of the liquid crystal panel. However, this requires modification of the display software. That is, the software is different between the device using the CRT and the device using the liquid crystal, and the compatibility is lost, which is a big problem.

An object of the present invention is to display an image in accordance with the size of the screen without changing the software when the resolution of the display device and the number of pixels of the image data are different, and the image can always be displayed on the entire screen. It is to provide a display device.

Another object of the present invention is to display the image on the entire screen without redrawing by processing the display data by the LCD controller when the resolution of the display device and the number of pixels of the image data are different. It is to provide an LCD controller.

[0006]

The above-mentioned two objects are to provide a resolution ratio setting means and an operation device for performing an operation between adjacent pixels in an LCD controller for transferring image data to a display device. According to the ratio of the image data obtained from the setting means and the resolution of the display, it is achieved by the arithmetic operation between the adjacent pixels by the arithmetic unit when the display data is transferred to the display.

[0007]

According to this method, re-drawing of the display memory is not necessary in order to enlarge / reduce the image when transferring the display data to the display. Therefore, the image can be displayed according to the size of the screen without changing the software, and the image can be always displayed on the entire screen.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of an image display device using the present invention. The CPU 10 uses the commands and data stored in the main memory 20 to control the LCD controller 30.
Generate a drawing command for. The LCD controller 30 draws a graphic on the display memory 40 according to the drawing command to generate image data to be displayed on the display unit 50. On the other hand, the LCD controller 30 includes a display unit 5
In order to display the image data at 0, the display memory 40 is read out periodically. The read data is transferred to the display unit 50 after being converted into serial data by the display data generation unit 3430. The serial data is latched in the LCD segment driver 510 in the display unit 50, becomes parallel data for one line of the liquid crystal panel 530, and is input to the lateral terminals of the liquid crystal panel 530.
On the other hand, the LCD common driver is the LCD controller 3
The signals in the vertical direction of the liquid crystal panel 530 are sequentially driven according to the control signal from 0.

The change of the display resolution which is a feature of the present invention is
It is realized by the CPU 10 setting the resolution in the resolution ratio setting means in the LCD controller 30. FIG. 3 shows an internal block of the LCD controller 30. The CPU bus interface is for performing data transfer between the CPU 10 and the LCD controller 30. The drawing control unit 320 follows the drawing command from the CPU 10 in the display memory 40 to draw straight lines, curved lines,
Draws surface figures, characters, etc. The display control unit 340 is a control unit for displaying the image data in the display memory 40 on the display unit 50. The image data to be displayed and the resolution of the liquid crystal panel 530 are set in the resolution ratio setting means 310. According to the setting, the timing generation unit 3420 causes the display address generation unit 3410 and the display data generation unit 3430.
And a control signal for the display unit 50. The display address generator 3410 calculates an address for reading the display memory 40, and reads the data in the display memory 40 according to the timing of the control signal. The read data is sent to the display data generation unit 3430. In the display data generation unit 3430,
The data is converted into serial data by the shift register 3431. If the display memory 40 and the liquid crystal panel 530 have the same resolution, the serial data is directly transferred to the display unit 50 as display data. However, if the resolutions are different, the following operation is performed. Here, a case where the number of pixels of the display memory is 640 × 480 and the resolution of the liquid crystal panel 530 is 800 × 600 will be described.
The serial data is sequentially transferred to the latch 3432 and the latch 3433. After that, the multiplier 3434 and the multiplier 343
5, the adder 3436 is used to perform calculation between the next pixel data.

I-th data of liquid crystal panel = ((i−1) th display memory data × coefficient 1) + ((i) th display memory data × coefficient 2) For example, the data of the display memory 40 is shown in FIG. In such a case, the data of the coefficient 1 and the coefficient 2 are sequentially calculated as follows while changing the data in the cycle of 5 pixels.

First pixel data of liquid crystal panel = first display memory data = 20 Second pixel data of liquid crystal panel = (first display memory data × 0.25) + (second display memory data × 0.2. 75) = (20 x 0.25) + (130 x 0.75) = 103 3rd pixel data of the liquid crystal panel = (2nd display memory data x 0.5) + (3rd display memory data x 0) .5) = (130 x 0.5) + (140 x 0.5) = 135 4th pixel data of the liquid crystal panel = (3rd display memory data x 0.75) + (4th display memory data x 0.25) = (140 × 0.75) + (50 × 0.25) = 118 5th pixel data of liquid crystal panel = 4th display memory data = 50 It is possible to obtain a good magnified image.

On the other hand, in the vertical direction, 600: 480 = 5: 4
Therefore, when the LCD common driver 520 drives a row which is a multiple of 5 of the liquid crystal panel 530, the display address generation unit 3410 calculates the same address as the row immediately before the row, and thus the display is expanded.

FIG. 5 shows a method of enlarging in the horizontal direction without performing such calculation. This method is realized by providing a shift clock adjustment circuit 3439 for adjusting the shift clock of the shift register 3431. FIG. 6 is a timing chart showing this operation example. In this example, the horizontal resolution is 800: 640 =
Since it is 5: 4, when the shift clock is a multiple of 5, by not performing the shift, the horizontal direction is 1.25.
Can be doubled. According to the method of FIG. 5, since it is not necessary to provide the display data generating unit 3430 with a multiplier or an adder, a low cost system can be constructed.

In the above example, the resolution of the display memory 40 is smaller than the resolution of the liquid crystal panel 530. However, in the present invention, the resolution of the display memory 40 is the liquid crystal panel.
It is also applicable when the resolution is higher than 530. For example,
An example of displaying 800 × 600 image data on a 640 × 480 liquid crystal panel will be described. Calculation of adjacent pixels by the display data generation unit 3430 in FIG. 3 shows that i-th data of liquid crystal panel = ((i−1) -th display memory data × coefficient 1) + ((i) -th display memory data ×
When calculating coefficient 2), it can be realized simply by changing coefficient 1 and coefficient 2. For example, the first pixel data of the liquid crystal panel = (first display memory data × 1.0) + (second display memory data × 0.2
5) Second pixel data of liquid crystal panel = (second display memory data × 0.75) + (third display memory data × 0.75)
5) 3rd pixel data of liquid crystal panel = (3rd display memory data x 0.5) + (4th display memory data x 0.5) 4th pixel data of liquid crystal panel = (4th display memory data) X 0.25) + (5th display memory data x 1.
The image may be reduced by periodically performing the calculation 0).

Also in the example of FIG. 5, the shift clock is controlled by the shift clock adjusting circuit 3439,
The image can be reduced. In the above example, when the shift clock is a multiple of the fourth pixel, the 1/2 cycle clock may be output twice. According to this method, since pixels are thinned out and displayed, the image data in the display memory 40 cannot be displayed accurately. However, when it is desired to display the outline of the image data, the display can be performed without changing the software. This is particularly effective in the case where a person can understand even if not all pixels are displayed as in a natural image.

In this embodiment, an example in which a liquid crystal panel is used for the display section is shown, but in addition to this, it is also applicable to an apparatus using a flat panel display such as a plasma display.

[0017]

According to the present invention, since the image can be enlarged / reduced without redrawing in the display memory, the display software is changed when the resolution of the image data and the resolution of the display are different. It is possible to display an image without it. Further, when the resolution of the display is higher than the resolution of the image data, the image data can be enlarged and displayed with the display panel such as a liquid crystal having no space.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an image display device according to the present invention.

FIG. 2 is an explanatory diagram showing a display example when the number of pixels of image data is smaller than the resolution of the display device in the conventional image display device.

FIG. 3 is an internal block diagram of an LCD controller.

FIG. 4 is an explanatory diagram showing a display example when the number of pixels of image data is smaller than the resolution of the display according to the present invention.

FIG. 5 is a block diagram showing another embodiment of the present invention.

FIG. 6 is an operation timing chart according to the method of FIG.

[Explanation of symbols]

10 ... CPU, 20 ... Main memory, 30 ... LCD controller, 40 ... Display memory, 50 ... Display unit, 310 ... Resolution ratio setting means, 3430 ... Display data generating unit.

Claims (5)

[Claims] 1. An image display apparatus, a display for displaying an image, a display memory for storing a displayed graphic as two-dimensional image data, and the display for displaying the image data stored in the display memory. A controller for displaying on a display unit, the controller having resolution ratio setting means for setting the ratio of the number of pixels of the image data of the display memory and the resolution of the display unit, the controller An image display device, characterized in that, when the image data is transferred to a display device, the image data is calculated between adjacent image data based on the resolution ratio setting means so that the data becomes a data suitable for the resolution of the display device. 2. In an image display device, a display device for displaying an image, a display memory for storing a displayed graphic as two-dimensional image data, and the image data stored in the display memory for the display device. And a controller for displaying the image data of the display memory and a resolution ratio setting means for setting the ratio of the number of pixels of the image data of the display memory to the resolution of the display. A shift register for transferring as serial data to the display unit, and when the controller transfers the image data to the display unit, the resolution ratio setting is set so that the data becomes data compatible with the resolution of the display unit. An image display device, wherein the shift clock of the shift register is adjusted based on the means. 3. The display according to claim 1 or 2,
An image display device that is a liquid crystal display. 4. A display controller for displaying image data stored in a display memory on a liquid crystal display,
The controller transfers resolution ratio setting means for setting the ratio of the number of pixels of the image data in the display memory and the resolution of the display and the image data in the display memory to the display as serial data. Shift clock of the shift register based on the resolution ratio setting means so that when the controller transfers the image data to the display device, the data becomes data suitable for the resolution of the display device. Liquid crystal display controller characterized by adjusting. 5. A display controller for displaying image data stored in a display memory on a liquid crystal display,
The controller has resolution ratio setting means for setting the ratio of the number of pixels of image data in the display memory to the resolution of the display, and when the controller transfers the image data to the display. A liquid crystal display controller, which calculates between adjacent image data on the basis of the resolution ratio setting means so that the data is adapted to the resolution of the display.