JP3533475B2 - Liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device,
In particular, it relates to a liquid crystal display device that performs color display using a ferroelectric liquid crystal.

BACKGROUND OF THE INVENTION In general, a substance that is polarized only when an electric field is applied from the outside is called a "dielectric". In particular, there is a polarization even when there is no external electric field (this polarization is spontaneous polarization). Is referred to as "ferroelectric". The ferroelectric substance has a characteristic that the direction of spontaneous polarization can be reversed depending on the direction of an applied electric field, and the spontaneous polarization can be aligned in one direction.

Some types of liquid crystals have such spontaneous polarization, and such liquid crystals are called "ferroelectric liquid crystals (F
LC: Ferroelectric liquid crystal) ". A liquid crystal exhibiting ferroelectricity is a smectic liquid crystal having an asymmetric carbon atom in its molecular structure, and smectic C in which liquid crystal molecules are inclined at a certain angle with respect to each layer is known. Since it has an asymmetric carbon atom, it is also called chiral smectic C, and the liquid crystal molecule has a helical structure like the chiral nematic liquid crystal (cholesteric liquid crystal).

However, the molecular arrangement is completely different from that of the cholesteric liquid crystal, and the long axes of the liquid crystal molecules are arranged so as to be inclined at a certain angle from the direction perpendicular to each layer. They are arranged so that they gradually shift to, and have a spiral structure. The dipole moment also rotates with the spiral.

The pitch of the spiral of the ferroelectric liquid crystal is usually on the order of several microns, but when the thickness of the liquid crystal layer becomes thinner than this spiral pitch, the spiral structure is dissolved and the liquid crystal molecules become aligned in one direction. . When a DC voltage is applied to the liquid crystal in such a state, the dipole direction, that is, the liquid crystal molecule direction can be switched by the positive or negative polarity of the voltage. The time required for this switching is much faster than the time required for the molecular arrangement in a nematic liquid crystal device or the like, and a response time shorter than one millionth of a second has been reported.

In the ferroelectric liquid crystal, in addition to such a high speed response, TN (twisted nematic) and STN (super t
wisted nematic), which has a bistability that results in two different optical stable states for two different types of electric field vectors. However, having a memory function to maintain a stable state of either, suitable for large-capacity display, wide viewing angle, etc.
In recent years, liquid crystal display devices using surface-stabilized ferroelectric liquid crystals, which display by utilizing the spontaneous polarization of the ferroelectric liquid crystals, have attracted attention because they have extremely excellent properties compared to conventional liquid crystals. ing.

The surface-stabilized ferroelectric liquid crystal is displayed by utilizing the spontaneous polarization of the ferroelectric liquid crystal, and the transition time to the above-mentioned two optically stable states is 100 μs or less, which is a normal liquid crystal. Very fast compared to
Since it is possible to obtain high contrast, it is expected as a flat panel display for OA.

However, the property of bistability, which is a characteristic of ferroelectric liquid crystals, becomes an obstacle to colorization (multi-gradation),
It is difficult to display halftones as they are.

Therefore, there is a demand for a color liquid crystal display that makes use of the excellent characteristics of the ferroelectric liquid crystal.

[0010]

2. Description of the Related Art Conventionally, color display devices using ferroelectric liquid crystals are roughly classified into color filter type LCDs (Li
A quid crystal display) and a color light source type LCD are under study.

The color filter type LCD is a birefringence type, dichroic type, or light scattering type transmission type ferroelectric LC.
D is used as a high speed black and white (B / W) optical shutter,
RGB micro color filters are built in this LCD. Then, a white backlight is added to the back surface of the LCD and is generally applied as a direct-view LCD.

Incidentally, as a typical driving method of a color filter type ferroelectric liquid crystal, as shown in [Table 1], there are a driving method such as a two-field method, a multiple line simultaneous erasing method and a four-pulse method. is there. Table 1 shows various driving methods and multiplex driving characteristics.

[0013]

[Table 1] An example of a ferroelectric color LCD with a built-in RGB micro color filter is a diagonal of 12 inches, a panel size of 260 × 200 mm ² , and a pixel number of 639 × 40.
A cell having a cell gap of 0 and a cell gap of 2 μm has already been provided.

The alignment film of this panel has a symmetrical PI / PI
A rubbing film is used and a hot cathode tube is used as a backlight.

FIG. 11 is a sectional view of a ferroelectric multi-color LCD. In FIG. 11, 101 is a polarizing plate and 10 is
2 is a glass substrate, 103R is a red color filter, 103G is a green color filter,
103B is a blue color filter, 103M
Is a black matrix, 104 is a transparent electrode, 105 is an insulating film, 106 is an alignment film, 107 is a ferroelectric liquid crystal, and 108
Is a sealing agent.

Incidentally, a plural (8 lines) simultaneous erasing method is adopted as a driving method of this color LCD.

However, in the color filter type LCD, since the color filter is provided on the surface of the liquid crystal display panel, the utilization efficiency of light from the backlight is extremely deteriorated, and R,
Since a color display pixel is configured by using three pixels of G and B as one unit, there is a problem that the resolution is lowered when compared with a monochrome liquid crystal display panel having the same pixel pitch.

On the other hand, the color light source type LCD is roughly classified into a direct view type in which an image displayed on the LCD panel is directly viewed and a projection type in which the image is enlarged and projected on a screen.

In the case of a direct-view type, RGB is used as a color light source of a color generation source used in combination with a ferroelectric LCD which is a high-speed black and white (B / W) light shutter.
A three-color color fluorescent lamp is used, and in the projection type, an RGB color light source in which high-intensity white light is separated by a dichroic mirror is generally used.

FIG. 12 is a schematic view of the essential parts of a direct-view color light source LCD. In FIG. 12, 201 is a liquid crystal display panel, 202 is a fluorescent lamp, 203 is a light source cell, and 2 is a light source cell.
Reference numeral 04R is a red color filter, 204G is a green color filter, 204B is a blue color filter, and 205 is a light guide plate having a diffusion plate formed on its surface.

With the above structure, the sequential color illumination (color se
quential lighting) method is explained.

FIG. 13 shows the color display principle of the sequential color illumination system.

In sequential color illumination, one frame period is divided into three subframes corresponding to R, G, and B of three primary colors, and an image of a specific color is written and a light source of a specific color is supplied during each subframe period. Is turned on and color display is performed.

Here, the written image of the specific color needs to be stored in memory during the lighting period of the light source of the specific color that follows.

That is, in the color light source type LCD, one frame period is divided into three sub-frames for use, so that the LCD is required to have a high response speed.

That is, in the color display LCD based on the sequential color illumination system, the response speed of the LCD is required to be at least 3 times higher than that of the RGB color system described above, but the light utilization efficiency is high. Therefore, a brighter display screen (at least 2 times or more) can be obtained as compared with the RGB color system, and since a color display pixel can be configured by one pixel, high resolution display which is 3 times as high as that of the RGB color system can be obtained. It will be possible.

Therefore, for an LCD using a ferroelectric liquid crystal, which excels in high-speed response, a color display method in combination with a monochrome (B / W) optical shutter is effective.

[0028]

However, in the color light source type LCD described above, one frame period is divided into three sub-frames by utilizing the high-speed response characteristic and the memory function of the ferroelectric liquid crystal. The image of the specific color that has been processed and written needs to be stored during the lighting period of the light source of the specific color that follows, which causes the following problems.

That is, in the color display LCD based on the sequential color illumination system, writing is performed by utilizing the memory effect which is a characteristic of the ferroelectric liquid crystal, but it depends on the memory effect of the ferroelectric liquid crystal. As a result, stable display quality cannot be maintained, and in order to improve the display quality, it is necessary to shorten the writing cycle by utilizing the high response speed which is another feature of the ferroelectric liquid crystal. Will occur.

Therefore, if one frame period is divided into three sub-frames and processed, each color cannot be obtained stably, and there is a problem that a color display with a correct color tone cannot be performed.

[0031]

An object of the present invention is to improve the display quality in color display in a liquid crystal display device using a ferroelectric liquid crystal.

[0032]

The invention according to claim 1 is
A liquid crystal display panel, liquid crystal drive means for driving the liquid crystal display panel, and light irradiation means for emitting red light, green light, and blue light from the back surface of the liquid crystal display panel in synchronization with the drive timing by the liquid crystal drive means. A light selection control unit that controls the irradiation time while selecting the color of the irradiation light emitted from the light irradiation unit, wherein the light selection control unit is
The liquid crystal drive means has a predetermined size with respect to the liquid crystal display panel.
Output timing of write signal output at each timing
Red light, green light and blue light
Outputs the write signal by irradiating one light at a time
The feature is that the irradiation of the irradiation light is ended at the same time when the
I am trying.

In this case, in addition to the invention described in claim 1,
The invention according to claim 2 is characterized in that the liquid crystal display panel is a liquid crystal display panel using a ferroelectric liquid crystal.

In this case, in addition to the invention of claim 1 or 2, the invention of claim 3 is characterized in that the light irradiating means is a red fluorescent lamp for irradiating red light, a green fluorescent lamp for irradiating green light, A blue light fluorescent lamp that emits blue light is provided, and the light selection control means selects a fluorescent lamp to be irradiated from among the fluorescent lamps of the light irradiation means, and a selection by the lamp selection portion. And a driving unit that drives the fluorescent lamp for a predetermined time.

In this case, in addition to the invention described in claim 1 or 2, in the invention described in claim 4, the light irradiation means has a white fluorescent lamp as a light source, and the light selection control means is An optical shutter unit that selectively transmits light emitted from the white fluorescent lamp, and a color filter unit that transmits light of a specific wavelength in the light transmitted through the optical shutter unit. Is characterized by.

Further, in this case, in addition to the invention according to claim 1 or 2, in the invention according to claim 5, the light irradiation means has a white fluorescent lamp as a light source, and the light selection control means is A color filter section that transmits a specific wavelength of light emitted from the white fluorescent lamp, and an optical shutter section that selectively transmits the light emitted through the color filter section. Is characterized by.

In this case, in addition to the invention described in claim 4 or 5, in the invention described in claim 6, it is effective that the optical shutter portion is an optical shutter using a ferroelectric liquid crystal cell. is there.

[0038]

According to the first aspect of the invention, the light selection control means causes red light to be emitted after a predetermined time has elapsed from the output timing of the write signal output from the liquid crystal drive means to the liquid crystal display panel at predetermined timing . Green light and blue
The write signal is generated by irradiating any one of the light beams at a proper time.
When the output of the
Therefore, the image formed on the liquid crystal display panel becomes the writing signal.
Color display is performed while being refreshed more .

In this case, when the ferroelectric liquid crystal display panel is used in the liquid crystal display device as described in claim 2, the display quality in color display is enhanced in the liquid crystal display device using the ferroelectric liquid crystal. .

In this case, in the invention described in claim 3,
In addition to the invention according to claim 1 or claim 2, a red fluorescent lamp, a green fluorescent lamp and a blue fluorescent lamp are independently provided as light irradiating means, and the lamp selecting unit irradiates from among the respective fluorescent lamps. The fluorescent lamp to be selected is selected, and the fluorescent lamp selected by the driving unit is driven for a preset time.

As a result, any one of the red light, the green light and the blue light is surely irradiated in synchronization with a plurality of write signals output from the liquid crystal driving means, and a color display of an accurate color tone is performed. Be seen.

Further, in this case, in the invention described in claim 4, in addition to the invention described in claim 1 or 2, the color filter is selected from the light transmitted from the white fluorescent lamp through the optical shutter portion. The light of a specific wavelength is selectively transmitted by the section, and a desired color light is emitted.

As a result, any one of the red, green, and blue lights is surely irradiated in synchronization with the write signals output from the liquid crystal driving means a plurality of times, and accurate color display is performed.

Further, in this case, in the invention described in claim 5, in addition to the invention described in claim 1 or 2,
Light from the white fluorescent lamp, to which light of a specific wavelength has been selectively transmitted by the color filter unit, is selectively transmitted via the optical shutter unit, and desired color light is emitted.

As a result, any one of the red, green and blue lights is surely irradiated in synchronization with the write signals output from the liquid crystal driving means a plurality of times, and accurate color tone color display is performed.

In addition, in the invention described in claim 6, in addition to the invention described in claim 4 or 5, a ferroelectric liquid crystal cell is used as an optical shutter portion,
A high-speed optical shutter can be obtained in a color light source type liquid crystal display device.

[0047]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS.

First, the structure of this embodiment will be described.

FIG. 1 is a block diagram showing the configuration of the main part of this embodiment.

In FIG. 1, the liquid crystal display device 1 comprises a liquid crystal display panel 2, a liquid crystal drive means 3, a light irradiation means 4, and a light selection control means 5.

FIG. 2 is a sectional view of the liquid crystal display panel 2.

The liquid crystal display panel 2 is, as shown in FIG.
Glass substrates 11 and 12, polarizing plates 13 and 14, transparent electrode 1
5, 16, alignment films 17, 18, spacer 19, liquid crystal layer 2
It consists of zero.

Polarizing plates 13 and 14 are formed on the outer surfaces of the glass substrates 11 and 12, respectively, and transparent electrodes 15 and 16 are formed on the opposite surfaces of the glass substrates 11 and 12, respectively.
And the alignment films 17 and 18 are formed on the surfaces of the transparent electrodes 15 and 16, respectively.

The alignment films 17 and 18 are organic polymer films that are subjected to a treatment such as rubbing to align the liquid crystal molecules, and are polyvinyl alcohol (PVA: Poly Vinyle Alcohol).
Alternatively, a polyimide resin is used.

The spacer 19 is for ensuring the uniformity of the gap between the glasses of the liquid crystal cell and has a diameter of 10 μm.
It has a spherical shape of m.

The liquid crystal layer 20 comprises two transparent glass substrates 1
Ferroelectric liquid crystal sandwiched between 1 and 12, and in this embodiment, a ferroelectric liquid crystal composed of an ester-based mixed composition having good stability is used.

FIG. 3 is a block diagram showing the main structure of the liquid crystal driving means 3.

As shown in FIG. 3, the liquid crystal driving means 3 is composed of a segment driving circuit 3a for driving the segment electrodes of the liquid crystal display panel 2 and a common driving circuit 3b for driving the common electrodes of the liquid crystal display panel 2. ing.

Then, these drive circuits operate in a VRAM based on a command from a microprocessor (not shown).
The image data stored in (Video Random Access Memory) or the like is received as a video signal by a video display processor or the like, and based on a video / timing control signal from the video display processor, the liquid crystal display panel 2
The above output is displayed.

FIG. 4 is a diagram showing a main configuration of the light irradiation means 4 and the light selection control means 5.

As shown in FIG. 4, the light irradiation means 4 is composed of a red fluorescent lamp 4R for emitting red light, a green fluorescent lamp 4G for emitting green light, and a blue light fluorescent lamp 4B for emitting blue light. There is.

Further, the light selection control means 5 comprises a driving unit 6 for driving the fluorescent lamps 4R, 4G, 4B and a lamp selecting unit 7 for selecting the fluorescent lamps 4R, 4G, 4B driven by the driving unit 6. The drive unit 6 is further configured.
Is composed of an R light emitting driver 6R, a G light emitting driver 6G, and a B light emitting driver 6B for making the respective fluorescent lamps 4R, 4G, 4B emit light, and the lamp selecting section 7 is a light emitting driver 6R, 6G used for backlight emission. , 6B for switching the display and 6B, and the respective light emitting drivers 6R, 6G, 6B
And a pulse generation circuit 7b for generating a light emission control pulse to be supplied to.

Next, the operation (action) of this embodiment will be described.

FIG. 5 is a waveform diagram showing drive signals for the liquid crystal display panel 2 and the fluorescent lamps 4R, 4G, 4B in this embodiment. In FIG. 5, DR is a red image data pulse, DG is a green image data pulse, DB is a blue image data pulse, PR is a light emission driver drive pulse for R, PG
Indicates a G light emission driver drive pulse, and PB indicates a B light emission driver drive pulse.

First, image data to be displayed on the liquid crystal display panel 2 is VRA via an A / D converter (not shown).
The red, green, and blue display image data in the VRAM stored in M (not shown) and then selected by the multiplexer (not shown) are passed through a video display processor (not shown) to generate a video signal. Is output to the segment drive circuit 3a and the common drive circuit 3b.

Then, in the segment drive circuit 3a and the common drive circuit 3b, as shown in FIG.
Each subframe period of R, G, B is set for each ec,
Furthermore, during each subframe period, red, green, and
Blue image data pulses DR, DG and DB are applied to the liquid crystal display panel 2.

Then, in synchronization with the output timing of the display image data, the display switching signal is sent to the display switching unit 7a in the lamp selecting section 7 at a timing delayed by 1/4 subframe period from the start timing of each subframe period. Along with the output, the backlight ON signal is output to the pulse generation circuit 7b, and the light emission driver drive pulse is selectively output to the predetermined light emission drivers 6R, 6G, 6B.

As a result, the R image is first written in the liquid crystal display panel 2 in the first ¼ sub-frame period, and after the writing is stabilized, the red fluorescent lamp 4 is written.
R is lit as a backlight only for 3/4 subframe period. By the way, in this case, the red image data pulse DR is output to the liquid crystal display panel 2 every 1/4 subframe period, so that the display image is refreshed every 1/720 sec.

Then, similarly to the writing of the R image,
G and B images are written, and R, G, and B are continuously written for a predetermined one frame period (1/60 sec in this case), so that one display pixel is visually displayed in color. It will appear as if it was done.

As a result, in the liquid crystal display device using the ferroelectric liquid crystal, the display quality in color display can be improved without depending on the memory property of the ferroelectric liquid crystal.

Another preferred embodiment of the present invention will be described below with reference to FIGS. 6 and 7. In FIGS. 6 and 7, the same parts as those in FIGS. 1 to 5 are designated by the same reference numerals.

FIG. 6 shows a liquid crystal display device 1 according to this embodiment.
FIG. 7 is a plan view showing a schematic configuration of FIG. 7, and FIG. 7 is a perspective view showing a configuration of a main part of the liquid crystal display device 1 in the present embodiment.

In FIG. 6, the light irradiation means 4 of the present embodiment.
Is composed of a white fluorescent lamp 4W serving as a light source and a light guide plate 4a, and the light selection control means 5 is an optical shutter portion 5a integrally formed between the white fluorescent lamp 4W and the light guide plate 4a.
And a color filter section 5b. The color filter section 5b is composed of a red color filter, a green color filter, and a blue color filter, respectively.

The white fluorescent lamp 4W comprises a cold cathode FL lamp arranged at the end of the light guide plate 4a, and irradiates light to the end face position of the light guide plate 4a via the optical shutter part 5a and the color filter part 5b. Is.

The light guide plate 4a is made of a transparent acrylic plate and guides the light incident from the end face to the back surface of the liquid crystal display panel 2, and the light guided by the light guide plate 4a is on the front surface of the liquid crystal. When the display panel 2 is irradiated, a diffuser plate (not shown) that diffuses the light to balance the brightness is formed, and a dot-shaped pattern is printed on the back surface and the light guide plate 4a is formed. A reflection plate (not shown) is formed so that the light entering the inside does not pass through the back surface of the light guide plate 4a and go out.

FIG. 8 is a sectional view of a ferroelectric liquid crystal cell which constitutes the optical shutter portion 5a.

The optical shutter portion 5a, as shown in FIG.
Glass substrates 21 and 22, transparent electrodes 23 and 24, insulating film 2
5, 26, alignment films 27 and 28, spacers 29, and ferroelectric liquid crystal layer 30.

Transparent electrodes 23 and 24 are formed on the facing surfaces of the glass substrates 21 and 22, respectively, and insulating films 25 and 26 are formed on the facing surfaces of the transparent electrodes 23 and 24, respectively. , 26 have alignment films 27, 2 on their surfaces.
8 forming.

The alignment films 27 and 28 are organic polymer films that are subjected to a treatment such as rubbing to align the liquid crystal molecules, and polyvinyl alcohol or polyimide resin is used.

The spacer 29 is for ensuring the uniformity of the gap between the glasses of the liquid crystal cell and has a diameter of 1.5.
It has a spherical shape of μm.

The ferroelectric liquid crystal layer 30 uses a ferroelectric liquid crystal composed of an ester-based mixed composition having good stability.

Each color (R,
The color filters of G and B) are coated with a color resin solution in which a coloring material such as a dye or an organic pigment is uniformly dispersed in a transparent photosensitive resin or a transparent resin by a dispersion method, and then exposed or developed or through a photoresist. Then, it is exposed and developed to sequentially form a colored pattern in a predetermined shape.

In the above configuration, first, red display image data is prepared based on a preset reference clock timing, and is decomposed into R, G, B in order to obtain a desired color display by a microprocessor (not shown). Based on each color information, a control signal is output to a driver (not shown) for driving the optical shutter unit 5a, and the optical shutter unit 5a corresponding to the red color filter of the color filter unit 5b has a predetermined timing. , And is turned on for a predetermined time, and red writing is performed in the R subframe. At this time, the optical shutter means 5a corresponding to the green color filter and the blue color filter are in the off state.

Next, green display image data is prepared,
The optical shutter portion 5a corresponding to the green color filter of the color filter portion 5b is turned on at a predetermined timing for a predetermined time, and green writing is performed in the G sub-frame. Thereafter, in the same manner, blue display image data is prepared, the optical shutter unit 5a corresponding to the blue color filter of the color filter unit 5b is turned on at a predetermined timing for a predetermined time, and in the B sub-frame. Blue writing is performed.

That is, in the above-described embodiment, the light emitted from each of the fluorescent lamps 4R, 4G, and 4B becomes the backlight light as it is, but in this embodiment, the white fluorescent lamp 4W is used as the light source. The light emitted from the white fluorescent lamp 4W is selectively transmitted through the color filter portion 5b by the optical shutter portion 5a to be colored, and then is radiated to the end portion of the light guide plate 4a so that the backlight of the liquid crystal display panel 2 (accurately It will be a sidelight).

As described above, in this embodiment, high-quality color display can be performed while taking advantage of the advantages of brightness and high resolution, which are the features of the color light source type liquid crystal display device.

FIG. 9 is a perspective view showing a main configuration of the liquid crystal display device 1 which is an alternative to that shown in FIG.

In the above-mentioned embodiment, the light emitted from the white fluorescent lamp 4W is selectively transmitted through the color filter portion 5b by the optical shutter portion 5a and is applied to the end portion of the light guide plate 4a. In the embodiment, the light emitted from the white fluorescent lamp 4W first becomes a predetermined colored light by passing through the color filter portion 5b, and this colored light is controlled to be transmitted / non-transmitted by the optical shutter portion 5a. Is.

As a result, in the present embodiment, similar to the above-described embodiments, high-quality color display is performed while taking advantage of the advantages of brightness and high resolution, which are the features of the color light source type liquid crystal display device. You can

Other preferred embodiments of the present invention will be described below.
This will be described with reference to FIG. In FIG. 10, the same parts as those in FIGS. 1 to 5 are designated by the same reference numerals.

FIG. 10 is a block diagram showing an example in which the liquid crystal display device 1 of this embodiment is applied to a television receiver.

In FIG. 10, 31 is a key input section for issuing a predetermined operation command to the television receiver, 32 is a tuning control circuit for controlling the tuning operation associated with the pressing of the tuning button in the key input section 31, 33 is an antenna, 34 is a tuner for receiving television broadcast radio waves,
35 is a TV linear circuit that amplifies the intermediate frequency signal based on the received signal of the tuner 34 and outputs a predetermined signal to the tuning control circuit 32, the audio circuit 36, the sync separation circuit 38 and the chroma circuit 39, and 36 is a TV linear circuit. An audio circuit that detects an audio signal based on the signal from the circuit 35 and converts the audio signal into a low frequency signal, 37 is a speaker that converts the audio signal output from the audio circuit 36 into audio and outputs 38
Is a horizontal synchronizing signal (H-SYNC signal) and a vertical synchronizing signal (V-SYNC) based on the signal from the TV linear circuit 35.
Signal), a sync separation circuit for separating each sync signal, 39 is T
A chroma circuit for A / D converting each color signal of R, G, B based on the signal from the V linear circuit 35 and storing the converted data on the field memory, 40 is a chroma circuit 3
A time-division control circuit that selects any one of the R, G, and B color signals output from 9 based on the timing set by the timing control circuit 41.
Reference numeral 1 is a timing control circuit that outputs a predetermined timing pulse to the tuning control circuit 32 and the time division control circuit 40 based on the synchronization signal from the synchronization separation circuit 38.

In the liquid crystal display panel 2 of this embodiment, S
A TN liquid crystal is used, and as a backlight, a light that is colored by the color filter unit 5b is actually used for the light emitted from the white fluorescent lamp 4W through a liquid crystal shutter made of a ferroelectric liquid crystal. However, in FIG. 10, for the sake of convenience, the irradiation of the light colored by the color filter portion 5b is changed to the fluorescent lamps 4R, 4 in FIG.
G and 4B are shown as being directly irradiated.

In the above configuration, the time division control circuit 40
The image data for one screen (for example, the image data for the R screen) stored in is sequentially output to the segment drive circuit 3a, and in synchronization with this, red light is emitted from the diffusion plate 4a by the drive unit 6.
It is illuminated as a backlight via.

Subsequently, the image data of the G screen is sequentially output from the time division control circuit 40 to the segment drive circuit 3a,
In synchronization with this, after green light is emitted from the drive unit 6 as a backlight through the diffusion plate 4a, in the same manner, the image data of the B screen is sequentially output from the time division control circuit 40 to the segment drive circuit 3a. , The drive unit 6 in synchronization with this
Thus, blue light is emitted as a backlight through the diffusion plate 4a.

As a result, although the liquid crystal display panel 2 itself has a monochrome structure, it is
Red image, green image, time-divided in 60 seconds
A blue image is displayed and a color image can be displayed.

Therefore, in the liquid crystal display device 1 of the present embodiment, in the color light source type liquid crystal display device, multi-gradation color display capable of displaying a television broadcast received image is performed while making the most of the advantages of brightness and high resolution. be able to.

Therefore, in the above-described embodiment, when the liquid crystal display device 1 is used as a display device connected to an information processing device such as a computer, that is, it is used as a color display device of about 16 to 256 colors. Although the case has been described as an example, in the present embodiment, since the liquid crystal display panel 2 using the STN liquid crystal as the display device of the television receiver enables the gradation control, it can be used as a full-color display device. Although the invention made by the present inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above-mentioned embodiment, the liquid crystal display panel 2 is composed of the ferroelectric liquid crystal, but the liquid crystal display panel 2 may be composed of a panel using TN or STN. The driving method of the display panel 2 is not limited to the simple matrix driving, but may be, for example, a TFT (Thin Film Trn).
An active matrix drive using an active element such as an anistor) may be used.

Although the color filter portion 5b is formed by the dispersion method in the above embodiment, the organic filter may be a dyeing method, a printing method, an electrodeposition method or the like. Alternatively, it may be formed by an inorganic filter using an inorganic material or a composite filter formed by a combination of these.

Further, in the above-mentioned embodiment, the liquid crystal composed of the ester-based mixed composition is used as the ferroelectric liquid crystal material, but the invention is not limited to this, and for example, a cyanobiphenyl-based liquid crystal or a multiplex operation is used. A phenylpyrimidine-based material that can obtain high contrast may be used, and any material may be used as long as it has characteristics as a ferroelectric liquid crystal material.

[0102]

According to the first aspect of the present invention, the red light is controlled by the light selection control means after a certain time has elapsed from the output timing of the write signal output from the liquid crystal drive means to the liquid crystal display panel at every predetermined timing. , Green light and blue
Irradiate any one of the colored lights at appropriate times, and
When the output of
Therefore, the image formed on the liquid crystal display panel is used as a writing signal.
Color display can be performed while refreshing more .

In this case, when a ferroelectric liquid crystal display panel is used in the liquid crystal display device as described in claim 2, the display quality in color display is enhanced in the liquid crystal display device using the ferroelectric liquid crystal. .

In this case, in the invention according to claim 3, as the light irradiating means, a red fluorescent lamp, a green fluorescent lamp and a blue light fluorescent lamp are independently provided, and the lamp selecting unit should irradiate from among the respective fluorescent lamps. The fluorescent lamp can be selected and the fluorescent lamp selected by the driving unit can be driven for a preset time.

Therefore, in addition to the first or second aspect of the invention, any one of the red light, the green light and the blue light can be surely synchronized in synchronization with a plurality of write signals output from the liquid crystal driving means. Light can be emitted, and accurate color display can be performed.

Further, in the invention described in claim 4, the light of the specific wavelength is selectively transmitted by the color filter portion from the light transmitted from the white fluorescent lamp through the optical shutter portion, and a desired color light is obtained. Can be irradiated.

Therefore, in addition to the first or second aspect of the invention, any one of the red, green and blue light is surely emitted in synchronization with a plurality of write signals output from the liquid crystal driving means. Irradiation is possible and accurate color display can be performed.

Further, in the invention of claim 5, the light from the white fluorescent lamp through which the light of the specific wavelength is selectively transmitted by the color filter portion is selectively transmitted through the optical shutter portion and is irradiated with the desired color light. can do.

Therefore, in addition to the first or second aspect of the invention, any one of the red, green, and blue light is surely emitted in synchronization with a plurality of write signals output from the liquid crystal driving means. Irradiation is possible and accurate color display can be performed.

In the invention described in claim 6, in addition to the invention described in claim 4 or claim 5, a color light source type liquid crystal display device is provided by using a ferroelectric liquid crystal cell as the optical shutter portion. A high-speed optical shutter can be obtained, and the refresh cycle can be set short.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a present embodiment.

FIG. 2 is a cross-sectional view of a liquid crystal display panel.

FIG. 3 is a block diagram showing a main configuration of a liquid crystal driving means.

FIG. 4 is a diagram showing a main configuration of a light irradiation unit and a light selection control unit.

FIG. 5 is a waveform diagram showing drive signals for a liquid crystal display panel and a fluorescent lamp in this example.

FIG. 6 is a plan view showing a schematic configuration of a liquid crystal display device according to another embodiment.

FIG. 7 is a perspective view showing a main configuration of a liquid crystal display device according to another embodiment.

FIG. 8 is a cross-sectional view of a ferroelectric liquid crystal cell forming an optical shutter unit in another embodiment.

FIG. 9 is a perspective view showing a main configuration of a liquid crystal display device according to another embodiment replacing FIG.

FIG. 10 is a block diagram showing an example in which the liquid crystal display device of the present embodiment is applied to a television receiver.

FIG. 11 is a sectional view of a ferroelectric multi-color LCD.

FIG. 12 is a main part configuration diagram of a direct-view type color light source type LCD.

FIG. 13 is a diagram showing a color display principle of a sequential color illumination system.

[Explanation of symbols]

1 Liquid crystal display 2 Liquid crystal display panel 3 Liquid crystal driving means 3a segment drive circuit 3b Common drive circuit 4 Light irradiation means 4R red fluorescent lamp 4G green fluorescent lamp 4B blue light fluorescent lamp 4W white fluorescent lamp 4a light guide plate 5 Light selection control means 5a Optical shutter unit 5b Color filter section 6 drive Light emitting driver for 6RR Light emitting driver for 6G G Light emitting driver for 6BB 7 Lamp selection section 7a Display switching device 7b pulse generator 11,12 glass substrate 13,14 Polarizer 15 and 16 transparent electrodes 17,18 Alignment film 19 Spacer 20 Liquid crystal layer 21,22 glass substrate 23, 24 Polarizer 25,26 transparent electrode 27,28 Alignment film 29 Spacer 30 Ferroelectric liquid crystal layer 31 Key input section 32 Tuning control circuit 33 antenna 34 Tuner 35 TV linear circuit 36 voice circuit 37 speakers 38 Sync Separation Circuit 39 Chroma circuit 40 time division control circuit 41 Timing control circuit 101 Polarizing plate 102 glass substrate 103R red color filter 103G green color filter 103B blue color filter 103M black matrix 104 transparent electrode 105 insulating film 106 Alignment film 107 Ferroelectric liquid crystal 108 Sealant 201 LCD display panel 202 fluorescent lamp 203 Light source cell 204R Red color filter 204G green color filter 204B blue color filter 205 light guide plate

Claims (6)

(57) [Claims] 1. A liquid crystal display panel, liquid crystal drive means for driving the liquid crystal display panel, and red light, green light, and blue light emitted from the back surface of the liquid crystal display panel in synchronization with the drive timing by the liquid crystal drive means. light projecting means for, as well as selecting the color of the illumination light emitted from the light irradiating means, and a light selection control means for controlling the irradiation time, the light selection control means, said liquid crystal drive means the LCD table
Writing to output to the display panel at predetermined timing
After a certain time has passed from the output timing of the
Irradiate any one of light, green light and blue light at appropriate time
Then, at the same time when the output of the write signal ends, the irradiation light
A liquid crystal display device characterized by terminating the irradiation of. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display panel is a liquid crystal display panel using a ferroelectric liquid crystal. 3. The light irradiating means has a red fluorescent lamp for irradiating red light, a green fluorescent lamp for irradiating green light, and a blue light fluorescent lamp for irradiating blue light, and the light selection control means comprises: A lamp selection unit that selects a fluorescent lamp to be irradiated from among the fluorescent lamps of the light irradiation unit; and a drive unit that drives the fluorescent lamp selected by the lamp selection unit for a preset time. The liquid crystal display device according to claim 1 or 2. 4. The light irradiating means has a white fluorescent lamp as a light source, and the light selection control means has an optical shutter section for selectively transmitting light emitted from the white fluorescent lamp, and the light irradiating section. 3. The liquid crystal display device according to claim 1, further comprising: a color filter unit that transmits light of a specific wavelength in the light transmitted through the shutter unit. 5. The light irradiation means has a white fluorescent lamp as a light source, and the light selection control means transmits a light of a specific wavelength in the light emitted from the white fluorescent lamp. 3. The liquid crystal display device according to claim 1, further comprising: an optical shutter unit that selectively transmits light emitted through the color filter unit. 6. The liquid crystal display device according to claim 4, wherein the optical shutter section is an optical shutter using a ferroelectric liquid crystal cell.