JPH03138692A - Image display device - Google Patents

Abstract

PURPOSE:To prevent the flicker of a boundary and to improve image display performance by selecting actually used gradations out of set gradations more than actually used so that adjacent gradations with conflicting display periods and gradations in such a condition are evaded and controlling a frame. CONSTITUTION:Gradations more than actually used, 32, for instance, are previously set, and among them, actually used gradations, 16, for instance, are selected so that adjacent gradations with conflicting display periods and gradations in such a condition are evaded, thereby controlling a frame. Consequently, even if any combination of gradations is adjacent to each other in an image, the flicker of a boundary is prevented to improve image display performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image display device, and more particularly to an image display device that improves the gradation display method of a flat display.

Among the peripheral devices of a computer system, the display is the most commonly used in functional combination with the keyboard unit.

With the development of computer utilization technology and the diversification of needs, there has been a demand for the development of technology that satisfies users, and various types of displays have appeared on the market. Recently, devices have appeared in which the size of the display itself becomes an issue, and the technology for forming display screens into panels is rapidly progressing.

In addition, with the demand for multi-gradation display in flat display systems, ease of identification of gradation display is required.
Therefore, there is a need for a display method that can easily realize such gradation display.

[Conventional technique]

FDP is a flat display device similar to liquid crystal displays, and is widely used in the displays of computer terminal devices for characters and graph ink. There are two types: AC type plasma displays, and AC type plasma displays.

As a conventional gradation display method used in a flat display, there is one shown in FIG. 4, for example.

This is an example in which one frame divided by the vertical synchronization signal v5sync is divided into 15 by the horizontal synchronization signal Hsync using 4-bit data D0 to D3 and displayed in gradation.
The numbers in the figure represent data lines.

Further, FIG. 5 shows the principle of 16-gradation display in that case, and in the figure, W/E represents the address (W double light, E: enable), and the hunting portion represents the lighting state. As shown in this figure, one frame is divided into four screens with different times (time = brightness ratio; 1; 2:4:8), and the combination of these screens displays 16 steps of brightness differences. are doing. That is, the brightness level is changed by the lighting ratio within one frame time.

[Problem to be solved by the invention]

However, in such a conventional image display device, as is clear from FIG.
], the display periods are completely contradictory, and the brightness differs by only one step, so when these gradations are placed next to each other during actual image display, the boundaries between them are distorted due to the illusion of the human eye. There was a problem in that fluctuations occurred in the images and the performance of image display deteriorated.

Such a problem is likely to occur when the difference in brightness between the two adjacent lights is small and the light emission periods are contradictory within a frame.

Generally, when displaying multiple gradations, it becomes possible to display an image using a large number of gradations, but because the luminance is subdivided, there are fewer combinations that allow adjacent gradations to be distinguished without fluctuations. There is a tendency. Therefore, it is desired that there be no fluctuation even with a small luminance difference while taking advantage of the multi-gradation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an image display device that can prevent boundary fluctuations and improve image display performance even when gradations with small brightness differences are adjacent to each other.

[Means to solve the problem]

In order to achieve the above object, the image display device according to the present invention performs frame control using a control circuit, and the frame control is performed by dividing a display period into a plurality of frames within a frame, and selecting a plurality of screens having different divided times. In an image display device that drives a driver to display multiple gradations on a display panel, the control circuit includes a gradation setting means for setting more gradations than the number of gradations actually required; A selection of selecting each gradation from among the gradations set by the setting means for the number of gradations actually used, avoiding cases where adjacent gradations have conflicting display periods or are close to it. A means is provided to perform the frame control.

[Effect]

In the present invention, more gradations (for example, 32 gradations) than the number of gradations actually required are set in advance, and adjacent gradations are selected as the gradation skeleton (for example, 16 gradations) to be actually used. Each gradation is selected so as to avoid display periods that conflict with each other or are close to each other, and thereby frame control is performed.

Therefore, even if gradations with small brightness differences are adjacent to each other, no boundary fluctuation occurs and image display performance is improved.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

1 to 5 are diagrams showing an embodiment of an image display device according to the present invention. FIG. 1 is a block diagram of an image display device. In this figure, 41 is an AC type FDP (plasma display panel), 42 is a data side driver, and 43 is an AC type FDP (plasma display panel).
is a line side driver, and 44 is a control circuit. PDP4
Reference numeral 1 has a resolution of, for example, 640×480 dots, and is a memory type that performs gradation display under frame control. The data side driver 42 and the line side driver 43 are driven by a drive signal from the control circuit 44.
A voltage is applied to each electrode of the DP 41 to cause a discharge, and the discharge causes plasma to emit light.

The control circuit 44 is for displaying 16 gradations by frame control, and a detailed block diagram is shown in FIG. 2. In FIG. 2, the control circuit 44 includes an interface circuit (T/F) 45, memories 46 to 49, and a drive pulse generation circuit 50. The interface circuit 45 has vertical and horizontal synchronization signals V5yne.
,, H5ync, a data (Data) signal, and a clock (D-CK) signal are input, and the interface circuit 45 divides the display period into five parts within the frame based on these signals, and divides the divided time into five parts. By selecting five different screens, the necessary processing is performed to create control signals for driving the data side driver 42 and line side driver 43. In this embodiment, in particular, the decoder 5
1 is built-in.

Based on the 4-bit data D0 to D, the decoder 51 determines the display period between adjacent gradations as many as the number of gradations actually used from among the 32 gradations formed including the later memories 46 to 49. This is for selecting 16 gradations that avoid conflicting or nearly contradictory states, and 16 selections are made using combinations of 4 bits (2' to 16).

The decoder 51 corresponds to selection means. On the other hand, setting 32 tones, which is more than the actually required 16 tones, is
Using the combination of 5 bits (2'=32) O-84 (corresponding to bit O to bit 4),
This is performed by a block including 49, and this portion constitutes the gradation setting means 52. Memo IJ46-49
81 to B4 are delayed by the necessary amount to produce 22 gradations of luminance within one frame as shown in FIG. In addition, in the example of Figure 3,
There are only 32 combinations with the same brightness ratio, but 22 brightness (gradations).Then, from among these 22 gradations, the decoder 51 selects the first one. The 16 gradations indicated by hatching in FIG. 3 are selected and sent to the data side driver 42.

Note that the brightness ratio of each bit BO to B4 is as follows.

On the other hand, the drive pulse generation circuit 50 generates drive pulses for driving the line side driver 43 based on the signal from the interface circuit 45.

In the above configuration, each synchronization signal V 5ync, , H5
In the interface circuit 45, decoding of [32] to [16] is performed based on the y-nc, data signal, and clock signal, especially by the decoder 51, and the gradation setting means 52
The 16th floor steel is selected from the brightness display of the 22nd floor steel generated by and a drive signal is output to the data side driver 42, while the drive pulse generation circuit 50 outputs a drive signal to the line side driver 43.

Therefore, the gradation frame actually used is 16-story steel as shown in FIG. 3, and an image is thereby displayed on the PDP 41.

In this case, in this embodiment, each gradation is selected so as to avoid display periods of adjacent gradations that are or are close to conflicting, as shown in FIG. in particular,
The selected gradations are shown as [1] to [15], but there is a 5% difference in brightness between gradations [7] and [8], and conflicting display periods must be avoided. It is being The same applies to other gradations. Therefore, in this embodiment, no matter what combination of gradations are placed next to each other on an image, it is possible to prevent boundary fluctuations and improve image display performance.

Note that although this embodiment is an example in which 16th grade steel is selected from 22nd grade steel, the application of the present invention is not limited to this, and can of course be applied to other gradations.

[Effects of the Invention] According to the present invention, even when gradations with small luminance differences are adjacent to each other, fluctuation of the boundary can be prevented, and image display performance can be improved.

[Brief explanation of the drawing]

1 to 3 are diagrams showing one embodiment of the image display device according to the present invention, FIG. 1 is a block diagram thereof, FIG. 2 is a block diagram of its control circuit, and FIG. 3 is its gradation display. FIG. 4 is a diagram showing a conventional gradation display signal, and FIG. 5 is a diagram explaining the principle of a conventional 16-story steel display. 41...PDP. 42... Data side driver, 43... Line side driver, 44... Control circuit, 45... Interface circuit, 46-49.
... Memory, 50 ... Drive pulse generation circuit, 51 ...
- Decoder (selection means), 52... Gradation setting means. Figure 1

Claims (1)

[Claims] Frame control is performed by a control circuit, and the frame control divides a display period into a plurality of frames within the frame, and drives a driver to display the display by selecting a plurality of screens having different divided times. In an image display device that displays multiple gradations on a panel, the control circuit includes a gradation setting means for setting more gradations than the number of gradations actually required; A selection means is provided for selecting each gradation for the number of gradations actually used from among the gradations so as to avoid display periods of adjacent gradations that conflict or are close to each other. An image display device characterized in that it performs control.