JP3749661B2 - Color image display apparatus and color image display method - Google Patents

Description

【００３１】
表１から明らかなように、本実施例では、解像度、輝度を決める最も重要な緑は、従来のシーケンシャル方式同様、カラーフィルター方式に比べて３倍としたまま、カラーブレイク、サブフレーム周波数、メモリー使用量は、それぞれ１／２，２／３，２／３に低減している。以上の結果から、本方式を用いれば、カラーシーケンシャル方式の利点をほとんど維持したまま、カラーブレイク、サブフレーム周波数、メモリー使用量といった課題を解決して、実現容易なカラーシーケンシャル型ディスプレイ装置を提供できる。
【００３２】
【発明の効果】
本発明によれば、従来のカラーシーケンシャル型ディスプレイ方式に比べ、サブフレーム、カラーブレイク、使用メモリのそれぞれを低減することが可能となり、デメリットの少ないカラー画像表示を実現できる。
【図面の簡単な説明】
【図１】本発明の一構成例を示す図である。
【図２】カラーフィルターの構成例を説明する図である。
【図３】カラーフィルターの分光特性を説明する図である。
【図４】カラーフィルターの配置例を説明する図である。
【図５】表示方法を説明するタイミングチャートである。
【図６】駆動回路の構成例を説明するブロック図である。
【図７】従来の構成例を示す図である。
【図８】従来の表示方法を説明するタイミングチャートである。
【図９】従来技術のカラーブレイクを説明する図である。
【図１０】従来の駆動回路の構成例を説明するブロック図である。
【符号の説明】
５１ バックライト
５２ 液晶パネル
５１０ 赤色ＬＥＤ
５１１ 緑色ＬＥＤ
５１２ 青色ＬＥＤ
５３ カラーシーケンシャル駆動回路
６１ 第1のカラーフィルター
６２ 第２のカラーフィルター[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color image display device that reproduces a color image using a plurality of basic colors.
[0002]
[Prior art]
In recent years, a color sequential display having a configuration as shown in FIG. 7 is used as an example. This display includes a light source 11 that sequentially emits three primary colors and a light valve 12 that displays an image as a change in transmittance in synchronization with the light emission of the light source. The light source 11 has a uniform luminance over the entire surface by a scattering plate or the like, and is used as a surface emitting light source.
[0003]
A time sequence is shown in FIG. During one frame 21 that displays the entire color image, the light sources of the three primary colors (R: red, G: green, B: blue) are sequentially emitted 22 and the corresponding color image is written in synchronization with it. A sub-frame 24 for displaying 23 on the valve is provided. In the subframe, first, electrical writing 23 of data to each pixel of the light valve is performed. Second, when data is written to each pixel, the liquid crystal of each pixel responds, but a certain time is required for the response. Normally, the liquid crystal response starts in order from the top because writing is performed sequentially from the top of the light valve, but the liquid crystal of the entire light valve completes the response, and the image is prepared on the light valve as a transmittance pattern. Is the timing when the last written pixel at the bottom ends the writing and the liquid crystal at that position completes the response. Therefore, thirdly, in the color sequential display, the backlight emits light at this timing 22, and the image is displayed as a luminance pattern.
[0004]
As an example, in the case of a video signal, since one frame is about 16.7 msec, each subframe 24 is about 5.6 msec. By making one frame time sufficiently short, since each primary color cannot be discriminated by human vision, colors are overlapped to achieve color display.
[0005]
As a result, one dot corresponds to one pixel of color pixel. As a result, three times higher resolution can be obtained compared to a method with a color filter on the liquid crystal panel, and no color filter is used. Since the absorption can be omitted, the transmittance can be increased by a factor of 3, and as a result, the power consumption can be reduced to 1/3.
[0006]
Hereinafter, a color emitted from a light source between subframes is referred to as a basic color.
[0007]
[Problems to be solved by the invention]
However, the conventional color sequential display has the following problems.
[0008]
(1) Occurrence of color break As shown in FIG. 9, when a line of sight tracks this when a moving object is displayed, there is a color break phenomenon in which a color appears on the contour 31, which occurs in principle in the color sequential method. If the frame frequency is increased, it is reduced, but the display device is required to have high-speed response, and the following problem (2) occurs instead.
[0009]
(2) Insufficient liquid crystal panel high-speed drive performance and liquid crystal high-speed response performance The liquid crystal panel high-speed drive and liquid crystal responsiveness three times that of the color filter system are required. If this is insufficient, problems such as a decrease in contrast occur.
[0010]
(3) Increase in cost of adding a memory for conversion to a field sequential signal In the field sequential method, the drive circuit shown in FIG. 10 is required. 42 is an RGB synchronous separation circuit, 43 to 45 are R, G, and B scanning speed conversion circuits each including a memory, and 47 is a backlight driving circuit for sequentially causing the light source 11 to emit light.
[0011]
As shown in FIG. 10, the input video signal 41 is separated into RGB three primary color image signals 42 and sequentially displayed on the liquid crystal panel at 3 × speed, the scanning speed conversion circuits 43, 44, 45 is provided, and this circuit requires a memory for storing temporary information. In the above conventional example, the memory requires three screens for three primary colors.
[0012]
The present invention solves the problems of the conventional color sequential method and provides a color sequential display device that is easy to implement.
[0013]
[Means for Solving the Problems]
The first invention is provided with a light source for emitting light of primary colors, in synchronization with light emission of the light source, the color image display device and a ride valve for controlling the transmittance for each pixel, the light source, at least One basic color is emitted at a timing different from that of the other basic colors, and a plurality of basic colors among the other basic colors are simultaneously emitted, and the ride bulb has a plurality of basic colors that the light source emits simultaneously. Rukoto to have a plurality of types of pixels passing through the respective you characterized.
In a second aspect of the invention, the basic colors are three primary colors of red, green, and blue, the light source emits red and blue simultaneously at a timing different from green, and the light valve is red and green. And a pixel that transmits blue and green.
A third invention is characterized in that the light source is a light emitting diode (LED).
[0014]
According to a fourth aspect of the present invention, there is provided a color image display device comprising: a light source that emits a basic color; and a light valve that controls transmittance for each pixel in synchronization with the light emission of the light source. 1 frame comprising a first subframe and a second subframe, the light source emits at least one basic color in the first subframe, and a plurality of other basic colors in the second subframe. At the same time light emission, and the ride valve, characterized in that have a plurality of types of pixels transmitted through each of the plurality of basic colors the light source emits light at the same time.
The fifth invention is characterized in that the first subframe and the second subframe are repeated a plurality of times during the one frame.
[0015]
A sixth invention is a color image display method for displaying an image using a plurality of basic colors, wherein one frame displaying the entire color image is divided into first and second sub-frames, In the first subframe, at least one basic color is displayed, and in the second subframe , a plurality of other basic colors other than at least one basic color displayed in the first subframe are simultaneously displayed. It is characterized by displaying.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail below with reference to the drawings.
[0017]
FIG. 1 is a diagram showing a configuration example of a color image display apparatus according to the present invention.
[0018]
This embodiment includes a backlight (light source) 51, a liquid crystal panel 52 as a light valve, and a color sequential drive circuit 53. Further, the backlight 51 includes a sufficient number of three types of LEDs (light emitting diodes) 54 that emit three primary colors of red, green, and blue to emit the necessary luminance. A scattering plate 55 for preventing color unevenness of the light beam is disposed on the LED. With this configuration, the LED backlight emits necessary primary colors in accordance with a signal from the drive circuit, and has a uniform luminance by the scattering plate 55, and functions to illuminate the liquid crystal panel 52 disposed on the upper part.
[0019]
Since the LED can be driven at a high speed with a response speed of about 1 μsec, it is optimal for pulsed emission of about 1 msec required by the color sequential method. Further, since the spectrum width is narrow, there is an advantage that the two-color transmissive filter used in the present invention can be easily designed.
[0020]
Next, in this embodiment, the liquid crystal panel 52 is a normal TN (twisted nematic) mode TFT (thin film transistor) liquid crystal panel. The configuration includes a TFT glass substrate and a counter glass substrate having a polarizing plate and a pixel driving circuit, a TN mode liquid crystal, and a color filter.
[0021]
However, the application range of the present invention is not limited to the above. The following method can be applied to all the light valves that control the light transmittance for each pixel.
[0022]
The first feature of the present invention resides in the color filters 61 and 62. As shown in FIG. 2, the color filter is arranged as a set of two pixels, and the respective spectral transmission characteristics are as shown in FIG. The first filter 61 transmits red and green as shown in FIG. 3A, and the second filter 62 displays green and blue as shown in FIG. 3B. To Penetrate. The two-dimensional arrangement method can be selected from either FIG. 4A in which the filters 61 and 62 are alternately arranged in a row or FIG. 4B in which the filters are alternately arranged, and can be selected according to the purpose of use.
[0023]
The second feature of the present invention resides in a backlight emission method and an image display method on a liquid crystal panel. FIG. 5 shows a timing chart.
[0024]
One frame 91 constituting the entire image is composed of two types of subframes 92 and 93. In the first sub-frame 92, first, a green signal separated from the input signal in advance in the color sequential drive circuit 53 is supplied to the liquid crystal panel 52, and a green image is displayed 94. The reason why there is an interval 95 between writing and backlight emission in the timing chart is to ensure the liquid crystal response time, and it can be changed depending on the liquid crystal used. With the transmittance pattern corresponding to the green image being prepared on the liquid crystal panel 52 in this way, only the green LED 510 emits light 96 at the end of the first subframe. Then, the color filter of the liquid crystal panel transmits green through both of the two types of color filters 61 and 62 , so that a green image is displayed.
[0025]
Next, in the second sub-frame 93, two kinds of video signals of red and blue separated by the color sequential driving circuit 53 are supplied, and a red signal is supplied to a pixel having a filter 61 that transmits red and green. The circuit in the liquid crystal panel is configured so that a blue signal is written to a pixel having a filter 62 that transmits green and blue. As a result, after the liquid crystal response time 98, a transmittance pattern corresponding to red and blue images is prepared on the liquid crystal panel 52. Therefore, when the red and blue LEDs 511 and 512 are simultaneously turned on at the end of the second subframe 93, the red and blue images are correctly displayed simultaneously through the filters corresponding to the pixels.
[0026]
Of course, the resolution of red and blue images is half that of green, but human visibility is the highest in green, and the resolution is mainly determined by green, so the reduction in red and blue display resolution is reduced to the overall resolution. Is less affected.
[0027]
The configuration of the subframes 92 and 93 is not limited to the configuration of the above embodiment. The order of the first and second subframes 92 and 93 can be exchanged, and the subframes 92 and 93 can be repeated a plurality of times to prevent a color break.
[0028]
Next, FIG. 6 shows a circuit configuration example of the color sequential drive circuit 53 of this embodiment. Reference numeral 71 denotes an RGB synchronous separation circuit, 72 denotes a G scanning speed conversion circuit including a memory, 73 denotes an R and B scanning speed conversion circuit, 74 denotes a timing control circuit, and 75 denotes a backlight driving circuit. The difference from the prior art is that, as described above, in this embodiment, it is composed of two types of subfields, so that the memory is reduced to two screens.
[0029]
Finally, the table compares the performance of this method with the conventional color sequential method and color filter method.
[0030]
[Table 1]

[0031]
As is apparent from Table 1, in this embodiment, the most important green for determining the resolution and luminance is the color break, the subframe frequency, the memory while maintaining the triple of the color filter method as in the conventional sequential method. The amount used is reduced to 1/2, 2/3, and 2/3, respectively. From the above results, if this method is used, it is possible to solve the problems such as color break, subframe frequency, and memory usage while maintaining most of the advantages of the color sequential method, and to provide an easy-to-implement color sequential display device. .
[0032]
【The invention's effect】
According to the present invention, compared with the conventional color sequential display method, subframes, color BREAK, it is possible to reduce the respective use memory can be realized disadvantage less color image display.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration example of the present invention.
FIG. 2 is a diagram illustrating a configuration example of a color filter.
FIG. 3 is a diagram illustrating spectral characteristics of a color filter.
FIG. 4 is a diagram illustrating an example of arrangement of color filters.
FIG. 5 is a timing chart illustrating a display method.
FIG. 6 is a block diagram illustrating a configuration example of a drive circuit.
FIG. 7 is a diagram illustrating a conventional configuration example.
FIG. 8 is a timing chart illustrating a conventional display method.
FIG. 9 is a diagram for explaining a color break in the prior art.
FIG. 10 is a block diagram illustrating a configuration example of a conventional drive circuit.
[Explanation of symbols]
51 Backlight 52 Liquid crystal panel 510 Red LED
511 Green LED
512 Blue LED
53 Color Sequential Drive Circuit 61 First Color Filter 62 Second Color Filter

Claims (6)

A light source that emits basic colors;
In a color image display device comprising a ride valve that controls transmittance for each pixel in synchronization with light emission of the light source,
The light source emits at least one basic color at a timing different from the other basic colors, and simultaneously emits a plurality of basic colors among the other basic colors,
The color image display device, wherein the ride valve has a plurality of types of pixels that transmit each of a plurality of basic colors emitted simultaneously by the light source. The color image display device according to claim 1,
The basic colors are three primary colors of red, green and blue,
The light source emits red and blue simultaneously at a timing different from green,
The light valve has a pixel that transmits red and green and a pixel that transmits blue and green. In the color image display device according to claim 1 or 2,
A color image display device, wherein the light source comprises a light emitting diode (LED). A light source that emits basic colors;
In a color image display device provided with a light valve that controls transmittance for each pixel in synchronization with light emission of the light source,
One frame displaying the entire color image is composed of first and second sub-frames,
The light source emits at least one basic color in a first subframe, and simultaneously emits a plurality of other basic colors in a second subframe ,
The ride valve, a color image display device which is characterized in that have a plurality of types of pixels transmitted through each of the plurality of basic colors the light source emits light at the same time. In the color image display device according to claim 4,
The color image display device, wherein the first subframe and the second subframe are repeated a plurality of times during the one frame. A color image display method for displaying an image using a plurality of basic colors,
One frame displaying the entire color image is divided into first and second sub-frames;
Displaying at least one basic color in the first sub-frame;
In the second subframe , a plurality of other basic colors other than at least one basic color displayed in the first subframe are simultaneously displayed.

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