JPH08160382A - Surface sequential liquid crystal display device - Google Patents

Abstract

PURPOSE: To obtain an inexpensive surface sequential display of high performance. CONSTITUTION: A monochromatic liquid crystal panel 1 functions as an image display means, and a sequential chrominance signal is driven as display data. And the device is provided with color filter means 3B, 3G and 3R for extracting respective B, G and R optical components from the light emitted from the light source 2 and the corresponding shutters 4B, 4G and 4R, and the shutters 4B, 4G and 4R are driven in synchronism with the sequential chrominance signal. Besides, the light outputted through the shutters 4B, 4G and 4R are entered through the side face of a light guiding panel 5, then, refracted toward the front side so that it may function as the back light for the liquid crystal panel 1. And also, three light sources corresponding to R, G and B are installed so that the sources may emit the light in synchronism with the sequential chrominance signal in the same way as the shutters 4B, 4G and 4R.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention drives a monochrome image display means with three primary color signals as sequential color signals which are time-divisionally supplied at predetermined intervals, and emits light in synchronization with the sequential color signals by required means. The present invention relates to a so-called frame-sequential display device that enables color display by switching colors.

[0002]

2. Description of the Related Art As a color display device, a color CRT or the like has been widely used in the past. However, since the electron beam of the three primary colors hits the fluorescent screen of the three primary colors, the convergence of the beam and the landing position of the beam are changed. Adjustment was necessary, which caused problems in contrast, resolution, and cost. On the other hand, a so-called frame-sequential type color display, which uses a monikro CRT or a monochrome liquid crystal panel as a display screen and temporally switches the emission of the three primary colors, has an advantage that such a problem does not occur.

A field-sequential color display that has been put into practical use is a system in which three primary color signals are temporarily stored in a memory and the color filters are switched and the sequential color signals from the memory are synchronized. In order to scan the three primary color signals within the time of one field, for example, the horizontal scanning and the vertical scanning are set to three times the normal one. As the color filter, a configuration in which the color filter is mechanically rotated and a configuration in which a color shutter including a liquid crystal shutter and a color polarizing plate are used are known.

FIG. 6 shows a signal waveform in the case of using a color shutter. FIG. 6A shows one field period of the input composite color video signal.
R reproduced from this composite color video signal,
The G and B primary color signals are simply compressed at 1/3 o'clock by a time base compression process using a memory, and B and R are divided into three equal parts within one field period as shown in FIG. 6B. , G are the sequential color signals in which the respective color signals are positioned. For example, a CRT display is driven by this sequential color signal.

A color shutter as shown in FIG. 7 is arranged on the front surface of the CRT. This color shutter includes three color polarizing plates 31, 33 and 35 and two π cells 3
2, 34. The color polarizing plate 31 on the most CRT side has a vertical polarization axis for the R signal and the G signal,
The polarization axis for the B signal is horizontal. The polarization axis of the color polarization plate 33 is perpendicular to the R signal, and the B signal and G
The polarization axis for the signal is horizontal. Further, the color polarization plate 35 has a horizontal polarization axis for each of the R, G and B signals and a vertical axis as a light absorption axis.

The π cells 32 and 34 are high-speed response liquid crystal shutters that are turned on / off by a drive pulse signal. The π cells 32 and 34 in the on state do not change the polarization direction of the passing light, while the π cells 32 and 34 in the off state rotate the polarization direction of the passing light by 90 °.

At the bottom of FIG. 7, a driving method of the π cells 32 and 34 is shown. During the period in which the CRT is driven by the B signal, both π cells 32 and 34 are turned on. Therefore, the B light having the polarization axes (horizontal) of the color polarization plates 31, 33 and 35 passes through the π cells 32 and 34, and the B image is obtained. Further, the π cell 32 is turned on and the π cell 34 is turned off while the CRT is driven by the R signal. Therefore, the R light from the color polarizing plate 31 is transmitted through the π cell 3
2 and the color polarizing plate 33, and the polarization direction is rotated by 90 ° by the π cell 34, and passes through the color polarizing plate 35. Therefore, an image of R is obtained. CRT by G signal
During the period when is driven, the π cell 32 is turned off and the π cell 34 is turned on. Therefore, the R light that has passed through the color polarizing plate 31 has its polarization direction rotated by 90 ° in the π cell 32, passes through the color polarizing plate 33, and then passes through the π cell 34 and the color polarizing plate 35 as it is. To be

That is, by synchronizing with the sequential color signals shown in FIG. 6B, drive signals Dπ ₃₂ and Dπ ₃₄ for the π cells 32 and 34 shown in FIG. 6C are generated to generate one field. In between, an image corresponding to each color signal is obtained, that is, a color image is obtained.

[0009]

By the way, in such a frame sequential display, a color shutter as shown in FIG. 7 is provided as a color filter, or a color filter is mechanically rotated although the description is omitted. You have to take the configuration. When a color filter that mechanically rotates the color filter is provided, there are problems of durability of the rotating body and an increase in space factor for the mechanism.

On the other hand, the system using the color filter as described above requires a liquid crystal shutter (π cell) and a color filter (color polarizing plate) of the same size as the screen of the CRT, that is, the display screen of the CRT or the like. In addition, a color filter that requires a fine printing process and a large-sized liquid crystal shutter that is relatively difficult to manufacture cause a cost problem. There is also a problem that the brightness of the display output is reduced due to such a multilayer structure.

[0011]

SUMMARY OF THE INVENTION In view of such problems, an object of the present invention is to provide an inexpensive and high performance frame sequential display.

Therefore, in the frame sequential display, first, a monochrome image display means using a liquid crystal panel is provided, and as a means for driving this, color signals are sequentially generated from the three primary color signals and supplied to the image display means as display data. And a drive signal generation means for generating horizontal and vertical drive signals synchronized with the sequential color signals and supplying the generated horizontal and vertical drive signals to the image display means. Further, a light source means serving as a backlight of the liquid crystal panel, and first, second, and third filter means for extracting different primary color light components from the three primary color light components included in the light from the light source means. , First,
First, second, and third optical shutter means are provided corresponding to the second and third filter means, respectively. Further, shutter drive means for opening and closing each of the first, second and third optical shutter means in synchronization with the color signal is provided. Further, the light output through the first, second, and third optical shutter means is incident from the side surface and is output to the front side, and the front side is arranged so as to face the image display means. Means are provided and the light is used as a backlight of the liquid crystal panel.

Similarly, in the frame-sequential type display, first, a monochrome image display means by a liquid crystal panel is provided, and as a means for driving this, color signals are sequentially generated from three primary color signals and supplied to the image display means as display data. And a drive signal generation means for generating horizontal and vertical drive signals synchronized with the sequential color signals and supplying the generated horizontal and vertical drive signals to the image display means. Further, first, second and third light source means for emitting and outputting different primary color lights are provided as a light source which serves as a backlight of the liquid crystal panel. Then, light source driving means for sequentially driving the first, second, and third light source means to emit light in synchronization with the color signals is provided. Further, the light output from the first, second, and third light source means is incident from the side surface and is output to the front side, and the front side is provided with the light guide means facing the image display means. The light is used as a backlight of the liquid crystal panel.

[0014]

With the above structure, the image display means can be composed of a monochrome simple matrix liquid crystal panel, which has the advantages of simplifying the manufacturing process and increasing the size of the screen. Further, in the case of a monochrome liquid crystal panel, it is not necessary to allocate pixels by R, G, B, so that a high definition image can be obtained. Further, since the backlight of the image display means is supplied through the light guide plate, the size of the screen does not need to be so large even if the screen is made large. Further, regarding the optical shutter means, allowing the light to enter the light guide plate means that the optical shutter means can be downsized regardless of the screen size.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an image display mechanism in a frame sequential liquid crystal display device of the embodiment. Reference numeral 1 denotes a liquid crystal panel which serves as an image display unit, and this liquid crystal panel is of a simple matrix monochrome type. Reference numeral 2 denotes a light source, which is arranged at a position that is not in the depth direction when viewed from the display surface of the liquid crystal panel 1.

The light from the light source 2 is emitted from the color filters 3B, 3
It is incident on G and 3R. The color filter 3B passes only the B light component from the light from the light source 2. Further, the color filter 3G passes only the G light component, and the color filter 3R passes only the R light component. Color filter 3B,
Color selection shutters 4B, 3G and 3R respectively
4G and 4R are arranged. Color selection shutters 4B, 4G,
4R is turned on / off by drive signals D _B , D _G , and D _R , which will be described later, and transmits or blocks light.

The light output through the color selecting shutters 4B, 4G, 4R is incident on the side surface of the flat light guide panel 5. The flat light guide panel 5 refracts incident light to make it flat,
That is, the light is guided to the liquid crystal panel 1 side, and the light from the light source 2 is thereby used as the backlight of the liquid crystal panel 1. Now, assuming that the color selection shutters 4B, 4G, and 4R are shaded and the color selection shutters 4B and 4R are in the closed state, and only the color selection shutter 4G is in the transmissive state, output from the light source 2. Of the generated light components, only the G light component is projected on the back surface of the liquid crystal panel.

A drive circuit system for such an image display mechanism is shown in FIG. Reference numeral 10 denotes a terminal to which the composite video signal CV is input. The composite video signal CV input from the terminal 10 is converted into digital data by the A / D converter 11 and supplied to the Y / C separation circuit 12. Then, the Y / C separation circuit 12 outputs the composite video signal CV to Y.
It is separated into a signal (luminance signal) and a C signal (chroma signal). The C signal is supplied to the color decoder 13 and the color difference signal (R
-Y, BY) and is supplied to the matrix circuit 14. The Y signal is also supplied to the matrix circuit 14.

In the matrix circuit 14, from the Y signal and the color difference signals (R-Y, B-Y), the B signal and R which are the primary color signals are provided.
Signal and G signal are reproduced. B signal, R signal and G signal are
The data is supplied to the memories 15B, 15R and 15G, respectively, and written according to the write clock from the write clock generator 21.

On the other hand, the Y signal from the Y / C separation circuit 12 is also supplied to the synchronization detection circuit 19 and the horizontal synchronization signal HD and the vertical synchronization signal VD are extracted. The horizontal synchronization signal HD and the vertical synchronization signal VD are supplied to the timing generation circuit 20 and used for various timing generations. The timing generation circuit 20 generates a timing signal according to the horizontal synchronization signal HD and the vertical synchronization signal VD, and the write clock generation unit 21.
To generate a write clock for the memories 15B, 15R, 15G. Further, the read clock generator 22 generates a read clock for the memories 15B, 15R, 15G.

In this case, by controlling the write clock and the read clock, the memories 15B, 15R, and 15G correspond to one field period of FIG.
As shown in (b), each of the 1/3 field periods is time-divided from the memories 15B, 15R, and 15G by 1/3.
The compressed B signal, G signal, and R signal are output.

The data read from the memories 15B, 15R and 15G is supplied to the multiplexer 16, but the timing generation circuit 20 is used in the memories 15B, 15R and 15G.
The multiplexer 1 is provided with a selection timing synchronized with each read timing of
The output of 6 becomes a sequential color signal as shown in FIG. This sequential color signal is supplied to the X-axis driver 17 of the liquid crystal panel 1 as display data.

Further, the timing generation circuit 20 supplies the operation timing signal T _H generated based on the horizontal synchronizing signal HD to the X-axis driver 17 of the liquid crystal panel 1, and Y
The operation timing signal T _V generated based on the vertical synchronizing signal VD is supplied to the axis driver 18. In this case, the operation timing signal T _V is a signal having a frequency three times that of the synchronization signal VD because scanning is performed three times in one field period.

The X-axis driver 17 is provided for each X electrode in the matrix configuration of the liquid crystal panel 1, that is, for each signal electrode.
The image data for one line of the color signal is sequentially output based on the image line timing generated from the operation timing signal T _H. On the other hand, the Y-axis driver 18 sequentially applies a voltage to each scan electrode so as to perform vertical scanning within the period of the operation timing signal T _V. As a result, on the liquid crystal panel 1, the image by the B signal is displayed in the first ⅓ period of one field, and the image by the G signal is displayed in the subsequent ⅓ period. R in the last 1/3 period
The image by the signal will be displayed.

Here, the timing generation circuit 20 gives the shutter driver 23 a timing for dividing one field into 1/3, and the shutter driver 23 accordingly responds to the drive signal D as shown in FIG. 3C. _B , D _G , D _R
Are applied to the color selection shutters 4B, 4G, and 4R, respectively.

That is, the color selection shutter 4B is set to the transmissive state in the first ⅓ period of one field.
Therefore, only the B light component extracted from the light source 2 by the color filter 3B is projected onto the liquid crystal panel 1 via the flat light guide panel 5. Liquid crystal panel 1 during this period
Since the image based on the B signal is displayed above, a blue image will be output. Further, in the next 1/3 period, the color selection shutter 4G is set to the transmissive state,
Therefore, only the G light component extracted from the light source 2 by the color filter 3G is projected onto the liquid crystal panel 1 via the flat light guide panel 5. Liquid crystal panel 1 during this period
Since the image based on the G signal is displayed above, a green image will be output.

In the last ⅓ period of one field, the color selection shutter 4R is in a transmissive state, so that only the R light component extracted from the light source 2 by the color filter 3R is flat light guide panel. The image is projected onto the liquid crystal panel 1 via 5. During this period, since the image based on the R signal is displayed on the liquid crystal panel 1, the red image is output. By outputting B, G, and R images in one field in this way,
That is, a color image of one field is displayed, and a frame sequential color liquid crystal display device is realized.

In this embodiment, the color filter 3
B, 3G, 3R and color selection shutters 4B, 4G, 4R
Need only be of a size capable of projecting light onto the side surface of the flat light guide panel 5, and may be of a considerably small size. Further, since the image display section may be a liquid crystal panel having a simple matrix structure, it is easy to increase the size and the manufacturing is simple. Further, since a monochrome liquid crystal panel is used, it is not necessary to distribute pixels by R, G, B, and a high-definition image can be obtained. Further, a display device having a small depth size can be realized by the configuration in which the backlight is projected on the liquid crystal panel 1 via the flat light guide panel 5.

Next, a second embodiment of the present invention will be described with reference to FIGS. In these figures, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
In the case of this embodiment, as shown in FIG. 4, three light sources 6B, 6G and 6R are provided on the side surface side of the flat light guide panel 5, and each emits primary color light. That is, the light source 6B emits B light, the light source 6G emits G light, and the light source 6R emits R light.

As can be seen from FIG. 5, the light source driver 24 is provided, and the light source driver 24 is shown in FIG. 3 (c) based on the timing signal from the timing generation circuit 20 which divides one field into 1/3. Drive signal D
Signals having the same timings as _B , D _G and D _R are applied to the respective light sources 6B, 6G and 6R. The operation of other parts is similar to that of the first embodiment.

Therefore, in the first ⅓ period of one field, the light source 6B emits light so that the B light component is emitted from the flat light guide panel 5.
The image is projected onto the liquid crystal panel 1 via. During this period, the blue image is output because the image based on the B signal is displayed on the liquid crystal panel 1. Further, in the next ⅓ period, the light source 6G is emitted and the G light component is projected onto the liquid crystal panel 1 via the flat light guide panel 5. During this period, since the image based on the G signal is displayed on the liquid crystal panel 1, the green image is output.

In the last ⅓ period of one field, the light source 6R emits light, and the R light component is projected on the liquid crystal panel 1 via the flat light guide panel 5. During this period, since the image based on the R signal is displayed on the liquid crystal panel 1, the red image is output. In this way, a color image is displayed and output on the liquid crystal panel 1 as in the first embodiment.

Also in this embodiment, as in the first embodiment, it is possible to adopt a liquid crystal panel which is large in size and easy to manufacture, and it is possible to obtain a high definition image. A display device having a small depth size can be realized by the configuration in which the backlight is projected on the liquid crystal panel 1 via the flat light guide panel 5. Further, in this embodiment, an extra light source is required as compared with the first embodiment, but since the color filter and the color selection shutter are unnecessary, the cost and space effects are almost the same as those of the first embodiment. It will be similar.

In the embodiment, the case of the sequential color signal in which each color signal is arranged every 1/3 period of one field has been described, but the present invention is not limited to this and, for example, B, G, and
The present invention can also be applied to other sequential color signal generation methods such as a method of generating sequential color signals in which color signals are arranged with R, B, G, R, B, G and R. It goes without saying that the timing of the opening / closing operation of each color selection shutter corresponding to the first embodiment and the switching operation of the light source for emitting light corresponding to the second embodiment are set according to the form of the color sequential signal. Nor.

[0035]

As described above, the frame-sequential type liquid crystal display device of the present invention can realize a color display by adopting a monochrome simple matrix liquid crystal panel as an image display means. There is an advantage that the screen can be easily enlarged, and further, since it is not necessary to distribute the pixels of the liquid crystal panel by R, G and B, there is an effect that a high definition image can be obtained.

Further, by supplying the backlight of the image display means through the light guide plate, it is possible to realize a display device having a small depth size without increasing the structural space even if the screen is enlarged. There is also an effect. Further, the optical shutter means has an advantage that it can be downsized regardless of the screen size. For these reasons, it is possible to realize a display device that has high performance, is inexpensive, and is easy to manufacture.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an image display mechanism according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a drive system of the image display mechanism of the first embodiment.

FIG. 3 is an explanatory diagram of an operation of the first embodiment.

FIG. 4 is an explanatory diagram of an image display mechanism according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a drive system of an image display mechanism of a second embodiment.

FIG. 6 is an explanatory diagram of an operation of a conventional frame sequential display device.

FIG. 7 is an explanatory diagram of a color shutter of a conventional frame sequential display device.

[Explanation of symbols]

 1 Liquid crystal panel 2, 6B, 6G, 6R Light source 3B, 3G, 3R Color filter 4B, 4G, 4R Color selection shutter 5 Flat light guide panel 14 Matrix circuit 15B, 15G, 15R Memory 16 Multiplexer 17 X-axis driver 18 Y-axis Driver 20 Timing generation circuit 23 Shutter driver 24 Light source driver

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04N 9/30

Claims (2)

[Claims] 1. A monochrome image display means using a liquid crystal panel, a sequential color signal generation means for sequentially generating color signals from three primary color signals and supplying the color display signals to the image display means as display data, and a sequential color signal synchronized with the sequential color signals. Driving signal generating means for generating horizontal and vertical driving signals and supplying the driving signals to the image display means, light source means, and three different primary color light components among the three primary color light components contained in the light from the light source means are extracted. First to do
Second and third filter means; first, second and third optical shutter means arranged corresponding to each of the first, second and third filter means; The light output from the second and third optical shutter means is incident from the side surface and is output to the front side, and the front side is arranged so as to face the image display means, and A frame-sequential liquid crystal display device, comprising: a shutter driving unit that opens and closes each of the first, second, and third optical shutter units in synchronization with a sequential color signal. 2. A monochrome image display means using a liquid crystal panel, a sequential color signal generation means for sequentially generating color signals from three primary color signals and supplying the color display signals to the image display means as display data, and a sequential color signal synchronized with the sequential color signals. Driving signal generating means for generating horizontal and vertical driving signals and supplying them to the image display means, and first, second, and third for emitting and outputting different primary color lights respectively.
And the light output from the first, second, and third light source means can be incident from the side surface and output to the front side, and the front side faces the image display means. And a light source driving unit that drives the first, second, and third light source units to emit light in synchronization with the sequential color signals. Frame sequential liquid crystal display device.