JP2002072208A - Liquid crystal display device, method of driving the same and illuminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device, a method of driving the same and an illuminator capable of reducing a silhouette coloring phenomenon of images generated in controlling a light emitting body in an illumination part in such a way as to assign a specified extinguished or dimmed period every one frame. SOLUTION: The liquid crystal display device is provided with a plurality of cold cathode tubes 3a, 3b having fluorescent materials sealed therein and making light, corresponding to driving signals, irradiate pixels and an inverter controlling circuit 1 controlling the driving signals in such a way as to make luminance of the cold cathode tubes 3a, 3b decrease around rise and fall every one frame. At least in the cold cathode tube 3a, only the fluorescent material with one color out of light's three primary colors is sealed. The driving signal applied to the cold cathode tube 3a is controlled by the inverter controlling circuit 1.

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 requiring a lighting device, a driving method of the liquid crystal display device, and a lighting device.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device used as a display screen of a notebook type personal computer, a word processor, or the like, when displaying a high-speed moving image, the display quality is deteriorated such as blurred or blurred image. Was done.

Therefore, Japanese Patent Application Laid-Open No. 1-082019,
Japanese Table flat 8-500915 and JP Hei 11-20
In Japanese Patent No. 2286, a light-emitting portion of a liquid crystal display device is formed so as to have a constant light-off period every vertical period,
Thus, it is disclosed that the display quality is improved in high-speed moving images.

[0004]

However, in the above-mentioned prior art, a white light-emitting body is used as a light-emitting body of the lighting unit. In this case, phosphors of at least three colors corresponding to the three primary colors of light are encapsulated, and the response time of the luminous body is different for each color, and as a result, the phase of the luminous waveform is different. This particularly causes a phenomenon in which the outline of the image is colored in the high-speed moving image, and the display quality is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an object to be achieved when a light-emitting body of a lighting unit is controlled so as to have a constant light-off or dimming period every vertical period. It is an object of the present invention to provide a liquid crystal display device which reduces the coloring phenomenon of the contour of an image.

[0006]

In order to solve the above-mentioned problems, a liquid crystal display device according to the present invention has a liquid crystal display device provided with a period in which the luminance of light applied to a pixel is reduced every vertical period. , Characterized in that a light-emitting body that independently emits at least one of the three primary colors of light is provided.

[0007] According to the above invention, light is applied to the pixels to display desired information. At this time, by providing a period in which the luminance of light applied to the pixel is reduced for each vertical period, only a moment having a high contrast ratio remains as an afterimage for a viewer, so that a clear screen with a good contrast ratio is seen. .

However, the luminous body is generally of a white type. In this case, phosphors of at least three colors corresponding to the three primary colors of light are encapsulated. A coloring phenomenon was observed, and as a result, the display quality was reduced. This is because the response time of the luminous body is different for each color, and as a result, the phase of the luminous waveform is different.

Therefore, according to the above-mentioned invention, a luminous body which independently emits at least one of the three primary colors of light is provided. By adjusting the phase of the light emission waveform from the light emitter, the phases of the light emission waveforms of the three primary colors of light can be brought closer to each other. Therefore, the phenomenon in which the outline of the image is colored in the high-speed moving image, which has occurred in the case of the white light-emitting body, is reduced, and the display quality in the high-speed moving image can be significantly improved.

According to the present invention, it is preferable that the luminous body that emits light at least independently emits only green light among the three primary colors. Among the phosphors that are generally used, the response time required for light emission and dimming of the green phosphor among the three primary colors is the longest, followed by red and blue.

Therefore, by independently providing the luminous body that emits only green light, it is possible to make the phase of the green light emission waveform close to that of the other blue and red light emission waveforms.

According to the present invention, it is preferable that the luminous body which emits light at least independently emits only blue light among the three primary colors. Among the phosphors generally used, the response time required for light emission and dimming of the green phosphor among the three primary colors is the longest, followed by red and blue.

However, if it is recognized that the luminous efficiency of the phosphor is slightly impaired, the response time required for green light emission / dimming is almost equal to the response time for red light, and only the blue response time is short. realizable. Therefore,
By independently providing a light emitter that emits only blue light, it is possible to make the phase of the blue light emission waveform close to the phase of the other green and red light emission waveforms.

Therefore, by independently providing the luminous body that emits only green light, it is possible to make the phase of the green light emission waveform close to that of the other blue and red light emission waveforms.

With respect to the other two primary colors different from the colors that emit light independently, a structure may be used in which light is emitted simultaneously from another light emitter, or a structure in which two light emitters are provided to emit light independently. In this case, a separate illuminant is assigned for each primary color, and by controlling independently,
It is possible to adjust the phases closer to each other with higher precision.

It is preferable that the light-emitting body further includes a light-emission control means for controlling at least one of a period during which the light luminance is not reduced and an amplitude of the light luminance. By controlling the period during which the brightness of the light is not reduced, the waveform width of the light emission waveform can be controlled, and the phases of the light emission waveforms can be closer to each other with higher accuracy. Also, by controlling the amplitude of the luminance of the light, the light emission timing can be similarly adjusted, so that the phases of the light emission waveforms can be brought closer to each other. By adjusting both the period during which the brightness of the light is not reduced and the amplitude of the brightness of the light, the light emission timing can be adjusted with higher accuracy.

In order to solve the above-mentioned problems, another liquid crystal display device according to the present invention includes a plurality of cold-cathode tubes in which phosphors are sealed and which irradiates pixels with light in accordance with a drive signal, and for each vertical period. A light emission control unit that controls the drive signal so that the rate of change of the luminance of the cold cathode tube with respect to time can be changed near a rise time and a fall time;
At least one of the cold-cathode tubes is filled with only a phosphor of one of the three primary colors of light, and a driving signal applied to the cold-cathode tube is controlled by the light emission control means. And

According to the above-described invention, light is irradiated to the pixels to display desired information. At this time, the drive signal is controlled by the light emission control means so that the rate of change of the luminance of the cold cathode tube irradiating the pixel with respect to the pixel every one vertical period is changed near the rise time and the fall time. By providing the period in which the brightness of the light is reduced in this way, only a moment having a high contrast ratio remains as an afterimage for a viewer, so that a clear screen with a good contrast ratio is seen.

However, in general, at least three color phosphors that emit green, red and blue light are sealed in the cold cathode tube. This phosphor emits fluorescence with ultraviolet rays emitted by mercury excited by discharge in the cold cathode tube. When this cold-cathode tube is turned on and off in a pulsed manner, the phases of the light emission waveforms of the respective colors are different (the response time required for light emission of the phosphor of each color and the response time required for quenching are different. Are different in light emission period). Such a difference in the phase of the light emission waveform causes a phenomenon in which the outline of the image is colored in a high-speed moving image, and as a result, the display quality is reduced.

Therefore, according to the invention, at least one of the cold-cathode tubes is filled with only a phosphor of one of the three primary colors of light, and a driving signal applied to this cold-cathode tube is Since the control is performed by the light emission control means, the phases of the light emission waveforms of the respective colors can be adjusted so as to approach each other.
Therefore, the phenomenon that the outline of the image is colored in the high-speed moving image is reduced, so that the display quality in the high-speed moving image can be significantly improved.

The cold-cathode tube comprises two cold-cathode tubes, one of which is filled with only the green phosphor of the three primary colors of light, and the other is the one of the three primary colors of light. It is preferable that the red and blue phosphors are enclosed.

In the emission waveform, among the three primary colors of light, green rises and falls particularly slowly. Therefore, a cold-cathode tube containing only green phosphors and a cold-cathode tube containing red and blue phosphors are provided independently, and the drive signal of each cold-cathode tube is controlled by the light emission control means. Thus, the phase of the emission waveform of the cold cathode tube in which the green phosphor is encapsulated and the phase of the emission waveform of the cold cathode tube in which the red and blue phosphors are encapsulated are adjusted so as to be more accurate. It becomes possible. Thereby, the phenomenon that the outline of the image is colored in the high-speed moving image can be reduced, and the display quality can be further improved.

According to the present invention, the cold cathode fluorescent lamp comprises two cold cathode fluorescent lamps, one of which contains green and red phosphors among the three primary colors of light. On the other hand, a configuration in which only a blue phosphor of the three primary colors of light is sealed is also preferable.

[0024] Generally used phosphors are selected based on their luminous efficiency and emission spectrum, but there are relatively many types of green phosphors for blue and red. Therefore, if a slight decrease in luminous efficiency is not taken into account, the green response time to light emission and dimming can be reduced to a time corresponding to almost red response time by selecting an appropriate phosphor.

Therefore, a cold cathode tube enclosing green and red phosphors and a cold cathode tube enclosing only blue phosphor are provided independently, and a driving signal of each cold cathode tube is controlled by light emission control means. This makes it possible to adjust the emission waveform phase of the cold-cathode tube in which the green and red phosphors are enclosed and the emission waveform phase of the cold-cathode tube in which only the blue phosphor is enclosed so as to be more accurate. It becomes possible. As a result, the phenomenon in which the outline of the image is colored in high-speed moving image display can be reduced, and the display quality can be further improved.

The cold-cathode tube comprises first to third three cold-cathode tubes. The first cold-cathode tube contains only a green phosphor of the three primary colors of light. Only the red phosphor of the three primary colors of light is sealed in the second cold cathode tube, and only the blue phosphor of the three primary colors of light is sealed in the third cold cathode tube. It is preferred that

According to the invention, the driving signals of the three cold cathode tubes are controlled by the light emission control means, respectively, as compared with the case where the two cold cathode tubes are used, so that the light emission waveforms of the three primary colors can be more precisely obtained. The phases can be close to each other, and the phenomenon that the outline of the image is colored in the high-speed moving image can be more reliably reduced, and the display quality can be further improved.

The definition for clarifying the discussion on the cold cathode tube and the light emission timing thereof in the present invention will be clarified. Since the generality is not lost, the first cold-cathode tube encloses a phosphor of one or two colors having a relatively long response time for light emission and dimming, and the second cold-cathode tube has a relatively long response time. A phosphor of one color or two colors having a short response time required for light emission and dimming is enclosed. Furthermore, if present, the third cold cathode fluorescent lamp is filled with a phosphor having the shortest response time, which is not sealed in the first and second cold cathode fluorescent lamps. That is, the response times of the phosphors of the three primary colors are generally shorter in the order of blue, red, and green, and therefore, combinations of the fluorescent tubes included in the present invention are shown in Table 1. Of course, even if the order of the phosphors to be actually enclosed is changed, there is no problem as long as it is controlled in accordance with the gist of the present invention.

[0029]

[Table 1]

Next, the emission and dimming timings are defined together with the inverter input signal timing. FIG. 8 shows a model diagram of a typical inverter input signal and light emission waveform. According to this figure, the light emission period, the light dimming period, the light emission timing,
The dimming timing and the vertical period are defined.

That is, the light emission period is a period from the time when the luminance reaches 90% with respect to the minimum luminance and the maximum luminance to a state where the luminance falls below 10%, and the other period is a dimming period.
Of course, 90% and 10% are for convenience of explanation,
It is temporarily determined and other numerical values, for example,
It goes without saying that using 50%, 20%, 80% or the like does not cause any inconvenience and does not affect the scope of the invention. The light emission timing is the time when the light emission period starts,
The dimming timing is defined by the time when the dimming period starts.

In addition, to make one cold cathode tube emit light (quenching) earlier (slower) than the other cold cathode tube means:
It shows the amount of change in light emission timing with respect to a state in which the timing of a drive signal for each conventional cold cathode tube is equal, and does not compare the light emission (extinction) periods of a plurality of cold cathode tubes. It goes without saying that the dimming includes the state of emission intensity 0 (zero), that is, the extinction state.

In the above-mentioned liquid crystal display device, the phenomenon in which the outline of an image in a high-speed moving image is colored is reliably reduced.
In order to improve the display quality, it is preferable that the emission control means controls the driving signal of each cold cathode tube at the following timing.

That is, the light emission control means is provided with the first
Each drive signal is controlled so that the cold-cathode tube emits light earlier than other cold-cathode tubes.

Alternatively, the light emission control means controls each of the drive signals so that the first cold-cathode tube dims earlier than other cold-cathode tubes.

Alternatively, the light emission control means controls each of the drive signals so as to emit light at an earlier timing in the order of the first cold cathode tube, the second cold cathode tube, and the third cold cathode tube.

Alternatively, the light emission control means controls each of the drive signals so that the first cold cathode tube, the second cold cathode tube, and the third cold cathode tube are dimmed at an earlier timing.

Alternatively, the light emission control means controls each of the drive signals so that the third cold cathode tube emits light at a timing later than the other cold cathode tubes.

Alternatively, the light emission control means controls each of the drive signals so that the third cold cathode tube dims at a later timing than the other cold cathode tubes.

In order to solve the above-mentioned problems, the illumination device according to the present invention irradiates a pixel of a liquid crystal display device, and has a light emission luminance at a certain phase with respect to a vertical synchronization signal during a light emission period. And a dimming period, wherein the dimming period is in the range of 10% to 90% of one vertical period, and the light emitting period and the dimming period of at least one of the three primary colors of light are independently set. It is characterized by controlling.

When the dimming period is less than 10% of one vertical period, a portion having good contrast cannot be selectively used. On the other hand, if the dimming period is longer than 90% of one vertical period, the overall luminance is reduced, and a good image cannot be obtained. Therefore, in the above lighting device, the dimming period is set in a range of 10% to 90% of one vertical period. As a result, a portion having good contrast can be selectively used, and a good image can be obtained without lowering the overall luminance.

The dimming period is 20% to 7% of the vertical period.
More preferably, it is in the range of 0%, and the dim period is 70%.
%, A moving image display performance comparable to that of a CRT can be expected. Therefore, it is not necessary to extinguish the light until the luminance is further lost. Also, if the dimming period is 20% as compared with the case of ordinary lighting, the moving image display performance can be clearly improved.

The luminous body is preferably a cold cathode tube, electroluminescence or hot cathode tube. These luminous bodies are generally widely used,
Excellent in mass productivity and cost.

It is preferable that the luminous body emits only green light among the three primary colors. The light emitter may emit only blue light among the three primary colors. Generally, green responds the least and blue responds the fastest. Therefore, by correcting the light emitter whose response time is farthest away (that is, the light emitter whose light emission period is out of phase), a preferable display can be obtained with a simple configuration.

The luminous body comprises a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors and a second cold-cathode tube containing a phosphor having a relatively short response time. Is preferred. At present, a cold cathode tube as a luminous body is most excellent in industrial use in terms of cost and productivity. Therefore, the cold-cathode tube is divided into two groups, one of which is a luminous body group having a relatively long response time (a large phase shift), and the other being a light-emitting group having a relatively short response time (a small phase shift). By performing correction as a body group, it is possible to provide a display that is excellent in cost and productivity and practically practical.

It is preferable that a green phosphor is sealed in the first cold cathode tube and a red and blue phosphor is sealed in the second cold cathode tube. Green and red phosphors may be sealed in the first cold cathode tube, and blue phosphors may be sealed in the second cold cathode tube.

Generally, among the phosphors, green responds the longest, and blue responds the fastest. Therefore, by correcting the light emitter whose response time is farthest away (that is, the light emitter whose light emission period is out of phase), a preferable display can be obtained with a simple configuration.

The luminous body includes a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors and a second cold-cathode tube containing a phosphor having an intermediate response time. It is preferable to include a third cold cathode tube in which a phosphor having a short response time is sealed. In this case, since the three primary colors are divided into three cold-cathode tubes, the light emission periods of the respective colors can be aligned with higher accuracy, and the most favorable situation on display can be realized.

An inverter for driving the luminous body,
It is preferable that the phase, amplitude, or pulse width of an input signal to the inverter is modulated so that the light emission period and the light reduction period are independently controlled.

There are the following three factors to make the light emission period uniform. That is, the start time and end time of the light emitting period, the length of the light emitting period, and the luminance profile at the start and end of the light emitting period. The phase modulation controls the start time of the light emitting period, and the pulse width modulation controls the length of the light emitting period and the accompanying end time of the light emitting period. And
The amplitude modulation controls the luminance profile at the start and end of the light emitting period. Among them, the start time has the largest influence, and then the end time is followed by the profile.

It is preferable that the light emitting period of the first cold cathode tube be controlled independently and be controlled so as to substantially coincide with the light emitting period of the second or third cold cathode tube. The light emission period of the second cold cathode tube or the third cold cathode tube is
It may be controlled independently and controlled so as to substantially coincide with the light emission period of the first cold cathode tube.

In principle, the illuminant has a waiting time of 0 and the emission period corresponding to the control signal starts and ends.
This is preferable for faithfully reproducing the intended display. However, in reality, a response time of 0 cannot be realized. Also,
In some cases, a high voltage circuit or a phase adjustment circuit, which is unnecessary in the past, may be required just to advance the phase.

Therefore, it is practical to make the light emitting periods of the cold cathode tubes substantially coincide with each other by correcting the relatively advanced phases of the light emitting bodies (the second and third cold cathode tubes). In this case, it is practical and effective to positively correct a longer response time and a larger phase shift to make the light emission periods of the cold cathode tubes substantially coincide with each other. Such correction can be made, for example, by delaying the phase.
The circuit for delaying the phase can often be realized by a relatively simple adjustment circuit. Therefore, it is possible to avoid complicating the configuration.

It is preferable that the light emitting periods of the first, second, and third cold cathode tubes are controlled independently of each other, and that the light emitting periods are controlled so as to substantially coincide with each other. By independently controlling the three cold-cathode tubes, the most preferable display can be surely obtained.

It is preferable that only the green phosphor is sealed in the first cold cathode tube. Green and red phosphors may be sealed in the first cold cathode tube. When two cold cathode tubes are provided, the illuminant having the largest phase shift should be controlled independently. That is, since the phosphor having the slowest response time is generally green and the phosphor having the fastest response is blue, the phase shift can be reliably reduced by enclosing the phosphor of any one color alone. . The desired effect described above can be obtained if the light emission periods of the one color light emitter and the two color light emitters are controlled so long as the respective light emission periods are approximately the same.

It is preferable that the cold cathode tube is provided at an end of an illumination unit in which light guides are spread, and irradiates the entire surface of the liquid crystal display device with the same phase. In this case, irradiation light is supplied to the liquid crystal display device through a light guide from a cold cathode tube provided at an end of the lighting unit.

At this time, the emission periods of the irradiation light corresponding to all the pixels coincide. Therefore, it is very important to set the start of the light emission period to which area on the screen. The display area in which the light emission period matches immediately after scanning by the liquid crystal display device is not completed because the response of the liquid crystal is not completed.
This provides a display one vertical period earlier. Generally, it is preferable that the timing in the center portion of the liquid crystal display device is best displayed in accordance with the period from when the liquid crystal display near the center is completed to when scanning near the center starts. According to the above configuration, this timing can be changed according to the purpose of use of the liquid crystal display device.

The cold-cathode tubes are divided into a plurality of regions having light-emission periods of different phases with respect to the vertical synchronizing signal. The same area of the liquid crystal display device is formed and illuminated. The areas of the different illuminated areas are substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction. Preferably, the periods are equally divided.

In the direct type lighting device, the cold cathode tube is:
The cold-cathode tubes, which are divided into a plurality of areas having light emission periods of different phases with respect to the vertical synchronization signal and have the same light emission period, collectively form a group of light emitters and illuminate the same area of the liquid crystal display device. And the area of different irradiation areas is
Each phase is substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction of the liquid crystal display device, and different phase differences equally divide one vertical period. It is possible to maintain a constant relationship between the phase of the light emitting period of the irradiation area and the phase of the light emitting period regardless of the display device. Therefore, it is possible to set a time zone in which the response of the liquid crystal is almost completed in all display areas to the light emission period. Therefore, a display showing good contrast over the entire display area can be obtained.

It is preferable that the number of the luminous body groups is in the range of 4 to 48. If the number of light emitter groups is less than 4,
The portion where the phase shifts with respect to the scanning of the liquid crystal display device increases. When the number of illuminant groups is greater than 48, the number of cold cathode tubes is close to 100 (at least 48 × 2
= 96), which is not practical from the viewpoint of mounting technology and cost.

[0061]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a liquid crystal display device according to the present invention will be described below with reference to FIGS.

First, the mechanism of the phenomenon in which the outline of an image is colored in a high-speed moving image will be described below with reference to FIGS.

The liquid crystal display device (active matrix type liquid crystal display device) shown in FIG. 6 mainly includes an inverter control circuit 1, an inverter 2, a cold cathode tube 3 (light emitting body), a liquid crystal panel control circuit 4, and a liquid crystal panel 5. Consists of

The inverter control circuit 1 receives the vertical synchronizing signal output from the liquid crystal panel control circuit 4 and outputs a drive signal for driving the inverter 2 to the inverter 2. A high voltage whose frequency changes according to the drive signal is applied from the inverter 2 to the cold cathode tube 3. When a high voltage is applied to the cold cathode tube 3, light is emitted from the cold cathode tube 3 and irradiates the liquid crystal panel 5.

When the video signal is input, the liquid crystal panel control circuit 4 separates the synchronizing signals, and the vertical synchronizing signal is sent to the inverter control circuit 1 as described above. Further, based on the video signal, a gate driver 5a and a source driver 5b for driving a scanning line and a signal line (both not shown) are respectively driven to select a desired pixel (not shown). The light radiated from is transmitted through the selected pixel to display the video signal.

Here, a description will be given of a case where the waveforms of the essential signals (vertical synchronization signal, input signal (drive signal) of inverter 2 and emission waveform of cold cathode tube 3) of the liquid crystal display device are as shown in FIG. .

In this case, by providing an extinguishing period (dimming period) for each vertical period, only a moment having a high contrast ratio remains as an afterimage for a viewer, so that a clear screen having a good contrast ratio can be seen. When displaying a high-speed moving image, a phenomenon in which the outline of the moving image was colored was observed.

In a liquid crystal display device, a cold cathode tube is used as a light emitter of a general lighting device. For cold cathode tubes,
Usually, phosphors of at least three colors that emit green, red, and blue light are enclosed. This phosphor emits fluorescence with ultraviolet rays emitted by mercury excited by discharge in the cold cathode tube.

When a cold cathode fluorescent lamp generally used for a lighting device of a liquid crystal display device is turned on and off in a pulsed manner,
It was found that the emission waveform was different for each color. In particular, it was found that the rise and fall of the green color were slow. That is, it was confirmed that the green light emission period was shifted backward with respect to blue and red. Therefore, an illuminating device was formed by two light-emitting portions, that is, a cold-cathode tube enclosing only a green phosphor and a cold-cathode tube enclosing phosphors of two primary colors, red and blue. Then, the phases of the drive waveforms for controlling the light-emitting members of the illumination unit were shifted for each light-emitting member so that a constant light-off or dimming period was provided for each frame. That is, the phases of the driving waveforms of the red and blue CCFLs are delayed from the phases of the driving waveforms of the green CCFLs. Thereby, the coloring phenomenon was reduced.

A total of three luminous bodies, a cold cathode fluorescent tube containing only a green phosphor, a cold cathode fluorescent tube containing only a red phosphor, and a cold cathode fluorescent tube containing only a blue phosphor, are used. A lighting device was formed. Then, the phases of the drive waveforms for controlling the light-emitting members of the illumination unit were shifted for each light-emitting member so that a constant light-off or dimming period was provided for each frame. That is, the phase is shifted backward in the order of green, red, and blue.

In general, the response time required for the phosphor to emit light is different from the response time required to reduce the light. Therefore, the length of the light emission period itself is slightly different for different phosphors. Therefore, it is more desirable to devise a method of adjusting the length of the light emitting period while shifting the phase. That is, as described above, not only the phase of the driving waveform is shifted by providing the light emitting element for each color, but at least one of the pulse width and the amplitude is controlled, so that the display quality can be further improved. On the other hand, such a driving method is effective for light-emitting elements other than the cold-cathode tubes, if the response time for each color is different.

Here, a liquid crystal display device according to an embodiment of the present invention will be described with reference to FIG. In addition,
Members having the same functions as those of the liquid crystal display device of FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 1, a cold-cathode tube 3a (first cold-cathode tube) enclosing only green phosphors and a cold-cathode tube 3b (second cold-cathode tube) enclosing phosphors of two primary colors, red and blue, are provided. A liquid crystal display device including two illuminating portions (cold cathode tubes) and inverters 2a and 2b for driving the illuminating portions, respectively, was manufactured.

In the inverters 2a and 2b, the period coincides with the vertical period in synchronization with the vertical synchronizing signal, and the pulse width thereof is 2/5 vertical period (corresponding to 2/5 of one vertical period). (Pulse (drive signal)) which is a period. However, the phase of the pulse (drive signal) input to the inverter 2a that drives the cold-cathode tube 3a is set to advance (advance) by, for example, 2 ms. The vertical synchronizing signal, the input signals of the inverters 2a and 2b, and the light emission waveforms of the cold cathode tubes 3a and 3b are as follows.
As shown in FIG.

When observing the rise and fall of the light emission waveform of the cold cathode fluorescent lamp 3a, they were dull as shown in FIG. Therefore, the light emission timing of the cold cathode tube 3a could be made closer to the light emission timing of the cold cathode tube 3b.

As described above, the two cold cathode tubes 3a and 3
b, and only the green phosphor is sealed in the cold-cathode tube 3a, and the two primary colors of red and blue are sealed in the cold-cathode tube 3b. The light emission timing can be brought closer to each other. As a result, when a high-speed moving image is displayed on such a liquid crystal display device, the phenomenon that the outline of the moving image is colored can be reliably reduced.

Here, another embodiment of the present invention will be described below with reference to FIG. Note that members having the same functions as those of the liquid crystal display device of FIG. 6 are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, a cold cathode tube 3a (first cold cathode tube) enclosing only a green phosphor, a cold cathode tube 3b (second cold cathode tube) enclosing only a red phosphor, And a cold-cathode tube 3c enclosing only a blue phosphor (third cold-cathode tube)
A liquid crystal display device including the three illumination units and inverters 2a, 2b, and 2c for driving the illumination units, respectively, was manufactured.

The inverters 2a, 2b, and 2c receive a pulse (drive signal) whose period coincides with the vertical period and whose pulse width is 2/5 vertical period, in synchronization with the vertical synchronizing signal. It was to so. However, the phase of the pulse (drive signal) input to the inverter 2a for driving the cold cathode tube 3a is earlier (advanced) by 2 ms than the phase of the pulse (drive signal) input to the inverter 2c.
Was set as follows. The pulse (drive signal) input to the inverter 2b for driving the cold cathode tube 3b has a phase of 1 m.
pulse (drive signal) input to inverter 2c by s
It was set so as to be earlier (advanced) than the phase of. FIG. 4 shows the vertical synchronizing signal, the input signals of the inverters 2a to 2c, and the light emission waveforms of the cold cathode tubes 3a to 3c, respectively.

When the rising and falling of the emission waveforms of the cold cathode tubes 3a and 3b were observed, they were dull as shown in FIG. However, the degree of blunting is greater for the cold cathode fluorescent lamp 3a (green). Therefore, the cold cathode fluorescent lamp 3
The light emission timing of a, the light emission timing of the cold cathode fluorescent lamp 3b (red), and the light emission timing of the cold cathode fluorescent lamp 3c (blue) could be brought close to each other.

As described above, the cold-cathode tube 3a containing the green phosphor and the cold-cathode tube 3b containing the red phosphor
By providing three cold-cathode tubes of a cold-cathode tube 3c enclosing a blue phosphor, and adjusting the phase of a drive signal for driving each of the cold-cathode tubes, more accurately than in the case of FIG. The light emission timings of the respective cold cathode tubes could be brought closer to each other. As a result, when a high-speed moving image is displayed on this liquid crystal display device, the above-described phenomenon in which the outline of the moving image is colored is greatly reduced, and the display quality is significantly improved.

Here, in FIG. 4, the inverter 2a
An example in which the waveforms input to (green) and the inverter 2b (red) are changed will be described below with reference to FIG.

That is, in FIG.
The input signal of a reduced the pulse width by 20% and increased the pulse height by 25%. On the other hand, the input signal of the inverter 2b reduced the pulse width by 15% and increased the pulse height by 20%. The blue color is the same as in the above embodiment. The vertical synchronizing signal, the input signals of the inverters 2a to 2c, and the emission waveforms of the cold cathode tubes 3a to 3c in this case are as follows.
The results are as shown in FIG.

At this time, the light emission timings and the luminances of the green, red, and blue colors are in good agreement. In such a liquid crystal display device, when a high-speed moving image is displayed, the above-described phenomenon in which the outline of the moving image is colored can be significantly reduced.

As described above, when not only the cold cathode tubes are provided for each color to shift the phase of the driving waveform but also to control at least one of the pulse width and the amplitude, the display quality can be further improved. .

Here, another embodiment of the present invention will be described. A liquid crystal display having the configuration of FIG. 9 was manufactured. The difference from FIG. 1 is that green and red phosphors are sealed in the cold cathode tube 3a ', and only blue phosphors are sealed in the cold cathode tube 3b'. The response time of the green phosphor has been improved so as to exhibit a light emission waveform substantially equivalent to that of red by improving the material.

Here, the improvement of the phosphor material will be briefly supplemented. Phosphor materials have been developed with the most emphasis on their emission spectrum, ie, display color (color purity) and luminous efficiency. In particular, the emission spectrum is the most important in determining the color balance of the entire display device. At present, the blue and red phosphor materials have virtually no room for change in their emission spectra, and there is little prospect of developing new materials for adjusting the response time.

On the other hand, green phosphor materials are relatively abundant in materials that satisfy the required emission spectrum, and there are many choices. As a result, it has become possible to develop a material having a light emission spectrum similar to that of the related art and comparable to the response time of the red phosphor without substantially sacrificing the light emission efficiency. In the present embodiment, such a green phosphor is employed and sealed in the cold cathode tube 3a 'together with the red phosphor.

In the inverters 2a and 2b, the period coincides with the frame frequency in synchronism with the vertical synchronizing signal, and the pulse width thereof is 2/5 frame time (2/5 of one frame time).
(A period corresponding to the length of / 5) (drive signal)
Was entered. However, a pulse (drive signal) input to the inverter 2a that drives the cold-cathode tube 3a '
Is set so that the phase is advanced (advanced), for example, by 1 ms. The vertical synchronization signal and the inverter 2
The input signals a and 2b and the emission waveforms of the cold-cathode tubes 3a 'and 3b' are as shown in FIG.

The rising of the emission waveform of the cold cathode fluorescent lamp 3a '
When observing the fall and the fall, as shown in FIG. Therefore, the light emission timing of the cold cathode tube 3a 'could be made closer to the light emission timing of the cold cathode tube 3b'.

As described above, two cold-cathode tubes 3a 'and 3b' are provided, phosphors of two primary colors of green and red are sealed in the cold-cathode tube 3a ', and the cold-cathode tubes 3b' are By enclosing the phosphor of only blue color, the light emission timing (phase of the light emission waveform) from the cold cathode tubes 3a 'and 3b' can be made closer to each other. As a result, when a high-speed moving image is displayed on such a liquid crystal display device, the phenomenon that the outline of the moving image is colored can be reliably reduced.

Also, since the red and green response times are close,
As shown in FIG. 2, the light emission periods became evener in each color, and the improvement of the high-speed moving image display performance was further improved.

In another embodiment of the present invention, the light emission period is adjusted by delaying the response time.
The liquid crystal display device of FIG. 9 is manufactured, and as shown in FIG. 11, a normal signal is input to the inverter in the cold cathode fluorescent lamp 3a ′, and a signal having a lower intensity than the normal is input to the inverter in the cold cathode fluorescent lamp 3b ′. (See the bold line 2b in FIG. 11).

As a result, the response time of the cold-cathode tube 3b 'was prolonged, and the light emission period almost coincided with that of the cold-cathode tube 3a'. When the high-speed moving image display of this liquid crystal display device was confirmed, the color separation was improved.

Here, a brief description will be given of delaying the response speed. Originally, in order to obtain a display as intended, it is naturally preferable that the display does not delay at all, that is, the response time approaches infinity. However, this sometimes requires an impractical voltage (this may be limited by setting the power supply of the entire liquid crystal display device, etc.). In such a case, it is effective to actually adjust the light emission period by lowering the response speed by using a voltage that is originally smaller than that of the actual product, and the effect expected by the present invention can be sufficiently obtained. I understand.

In the above description, the case where the cold cathode tube is used as the light emitting body has been described. However, the present invention is not limited to this, and the light emitting body having a different response time in the emission color (the cold cathode tube) is used. Alternatively, an electroluminescence element or a hot cathode tube can be used.) By adjusting at least one of the phase, the pulse width, and the pulse height of the applied voltage waveform for driving, the coloring phenomenon of the contour does not occur. A liquid crystal display device having extremely good moving image display quality can be provided.

Further, in the above description, the case where the phase difference between the drive signals of inverters 2a and 2c is 2 ms and the phase difference between the drive signals of inverters 2b and 2c is 1 ms has been described, but the present invention is not limited to this. Instead, the phase difference may be determined so that the emission waveforms of the cold cathode tubes 3a to 3c approach each other. Further, in the above, an example in which the pulse width and the pulse height are adjusted has been described, but the reduction ratio of the pulse width and the enlargement ratio of the pulse height in the description are merely examples, and the present invention is limited to these examples. Instead, the pulse width and / or the pulse height may be determined so that the emission waveforms of the cold cathode tubes 3a to 3c approach each other.

In the embodiment according to the present invention, the effect is confirmed using an interlaced video signal, but the present invention is not limited to this. For example, even when the present invention is applied to a non-interlaced (progressive) video signal, the same operation and effect as described above can be achieved. 1 for interlaced video signals
Although the vertical period is one field, one vertical period corresponds to one frame for a non-interlaced video signal.

Here, the lighting device according to the present invention will be described below. FIG. 12 shows a lighting device 100 according to the present invention.
FIG. 3 is a block diagram illustrating a configuration example of FIG. As shown in FIG. 12, the liquid crystal panel control circuit 111 drives the liquid crystal panel 112 based on the video signal and, at the same time, transmits a signal synchronized with a vertical synchronization signal (not shown) to the light emitting body control circuit 101. The light emitter control circuit 101 is configured to control a plurality of light emitter drive circuits 102 to 104 (corresponding to the above-described inverter). Light emitting element driving circuit 1 described above
02 to 104 correspond to the corresponding light emitting bodies 105 to 10 respectively.
7 lights up. At least one of the light emitter driving circuits 102 to 104 is independently controlled,
The illuminant corresponds to at least one of the three primary colors.

When the luminous bodies 105 to 107 are cold cathode tubes, the luminous body control circuit 101 corresponds to the inverter control circuit 1 described above. At that time, the relationship among the light emission profile of a certain cold cathode tube, the vertical synchronization signal, and the inverter input signal is as shown in FIG. 13, for example. Note that the light emission period and the dimming period are defined as shown in FIG. In other words, the present lighting device 100 sets the dimming period of at least one of the three primary colors of light from 10% of one vertical period to 90%.
% Can be controlled independently.

When the dimming period is less than 10% of one vertical period, a portion having good contrast cannot be selectively used. On the other hand, if the dimming period is longer than 90% of one vertical period, the overall luminance is reduced, and a good image cannot be obtained. Therefore, in the above lighting device 100, the dimming period is 1
It is set in the range of 10% to 90% of the vertical period.
As a result, a portion having good contrast can be selectively used, and a good image can be obtained without lowering the overall luminance.

The dimming period is from 20% of the vertical period to 7%.
More preferably, it is in the range of 0%, and the dim period is 70%.
%, A moving image display performance comparable to that of a CRT can be expected. Therefore, it is not necessary to extinguish the light until the luminance is further lost. Also, if the dimming period is 20% as compared with the case of ordinary lighting, the moving image display performance can be clearly improved.

Here, another lighting device of the present invention will be described. A backlight directly under the cold-cathode tube shown in FIGS. 14A and 14B was produced. The direct-type backlight is, for example, provided in a horizontal direction by being divided into four blocks 121 to 124 (each block is a lighting device), each block is partitioned via a partition plate, and incident light from each light emitter is provided. Is further provided to reflect light to the liquid crystal panel. In such a configuration, a certain display area is intensively illuminated by blocks arranged therebelow, and the illumination effect of adjacent blocks is relatively small. Here, since each block has the same configuration, the block 121 will be described for convenience of description.

The block 121 has a luminous body 121b in which only a green phosphor is encapsulated, and a luminous body 121a in which blue and red phosphors are encapsulated. The light emitter 121b is connected to a light emitter control circuit 201 via a light emitter drive circuit 202, for example, as shown in FIG. Further, the luminous body 121a is a luminous body driving circuit 2
03 is connected to the light emitter control circuit 201.
The other blocks 122 to 124 are also connected to similar circuits (not shown), and are driven at timing different from that of the other blocks.

As shown in FIG. 16, the luminous body 121a
Is driven at a standard timing, and the light emitting periods of the respective light emitting members can be substantially matched by shifting the driving timing of the light emitting members 121b so as to be advanced.

In order to advance the drive timing of the light emitting body 121b, for example, as shown in FIG. 16, a dummy synchronization signal having the same cycle as the vertical synchronization signal may be used instead of the vertical synchronization signal. Accordingly, the control signal of the light emitter control circuit 201 is shifted in phase (advanced in phase) as shown in FIG. 16, and as a result, the light emission timing of the light emitter 121a and the light emission timing of the light emitter 121b can be substantially matched. Becomes It should be noted that the dummy synchronization signal in the figure is introduced to explain that the luminous bodies driven at the same timing change the phase of the luminous period due to the difference in response time.

Here, with reference to FIG. 17, an example in which the shift of the light emitting period of the plurality of light emitters in the present invention is reduced will be described. In this case, the lighting devices of FIGS. 14 and 15 were manufactured. Rather than advance the drive timing of the light emitter 121b, the inverter input signal was increased as shown in FIG. As a result, the response time of the light emitting body 121b was shortened, and the shift between the light emitting periods of the light emitting body 121a and the light emitting body 121b was reduced.

Although the luminous body 121b has been described as emitting only green light among the three primary colors, the present invention is not limited to this.
Light emitting only blue light among the primary colors may be used. In general,
Green responds the least and blue responds the fastest. Therefore, the illuminant with the most distant response time (ie,
A desired display can be obtained with a simple configuration by correcting the light-emitting element whose light-emitting period is most out of phase.

The luminous body 121a is formed of a cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors, and the luminous body 121b is formed of a cold cathode containing a phosphor having a relatively short response time. It preferably comprises a tube. At present, cold cathode tubes as luminous bodies are the most
Excellent in cost and productivity. Therefore, the cold-cathode tube is divided into two groups, one of which is a luminous body group having a relatively long response time (a large phase shift), and the other being a light-emitting group having a relatively short response time (a small phase shift). By performing correction as a body group, it is possible to provide a display that is excellent in cost and productivity and practically practical.

It is preferable that a green phosphor is sealed in the light emitting body 121a, and a red and blue phosphor is sealed in the light emitting body 121b. The luminous body 12
Green and red phosphors may be sealed in 1a, and blue phosphor may be sealed in the light emitting body 121b.

In general, among the phosphors, green responds the slowest and blue responds the fastest. Therefore, by correcting the light emitter whose response time is farthest away (that is, the light emitter whose light emission period is out of phase), a preferable display can be obtained with a simple configuration.

In the above description, the three primary colors are 2
Although the description has been given of the case where the light emitting device is constituted by the cold cathode tubes, the present invention is not limited to this.
The first that encapsulates a phosphor with a relatively long response time among the primary colors
The second, in which a cold-cathode tube and a phosphor with an intermediate response time are enclosed
It may be composed of a cold-cathode tube and a third cold-cathode tube enclosing a phosphor having a relatively short response time (see the configuration of FIG. 12 including the light-emitting members 105 to 107). In this case, since the three primary colors are divided into three cold-cathode tubes, the light emission periods of the respective colors can be aligned with higher accuracy, and the most favorable situation on display can be realized.

The luminous bodies (121a, 121b, 105)
To 107) to drive the light emitter driving circuits (202, 20).
3, 102 to 104), and it is preferable that the phase, amplitude, or pulse width of an input signal to the light emitter driving circuit (inverter) is modulated so that the light emission period and the light reduction period are independently controlled. .

There are the following three aspects to make the light emission periods uniform. That is, the start time and end time of the light emitting period, the length of the light emitting period, and the luminance profile at the start and end of the light emitting period. The phase modulation controls the start time of the light emitting period, and the pulse width modulation controls the length of the light emitting period and the accompanying end time of the light emitting period. The amplitude modulation controls the luminance profile at the start and end of the light emission period. Among them, the start time has the largest influence, and then the end time is followed by the profile.

It is preferable that the light emitting period of the luminous body 105 is controlled independently and controlled so as to substantially coincide with the light emitting period of the luminous bodies 105 to 107. The light emitting period of the light emitting body 106 or 107 may be controlled independently and may be controlled so as to substantially coincide with the light emitting period of the light emitting body 105.

In principle, the luminous body has a waiting time of 0, and the luminous period corresponding to the control signal starts and ends.
This is preferable for faithfully reproducing the intended display. However, in practice, a response time of 0 cannot be realized. Also,
In some cases, a high voltage circuit or a phase adjustment circuit, which is unnecessary in the past, may be required just to advance the phase.

Therefore, it is practical to make the light emitting periods of the cold cathode tubes substantially coincide with each other by correcting the light emitting bodies 106 and 107 having relatively advanced phases. In this case, it is practical and effective to positively correct a longer response time and a larger phase shift to make the light emission periods of the cold cathode tubes substantially coincide with each other. Such correction can be made, for example, by delaying the phase. The circuit for delaying the phase can often be realized by a relatively simple adjustment circuit. Therefore, it is possible to avoid complicating the configuration.

The light emitting periods of the light emitting bodies 105 to 107 are as follows.
It is preferable that the light emitting periods are controlled independently and controlled so that the light emitting periods substantially coincide with each other.
By controlling the three luminous bodies 105 to 107 independently, the most preferable display can be surely obtained.

Further, as described above, the light emitting body 121b
It is preferable that only the green phosphor is sealed.
Green and red phosphors may be sealed in the light emitting body 121b. When two cold cathode tubes are provided, the illuminant having the largest phase shift should be controlled independently. That is, since the phosphor having the slowest response time is generally green and the phosphor having the fastest response is blue, the phase shift can be reliably reduced by enclosing the phosphor of any one color alone. . The desired effect described above can be obtained if the light emission periods of the one color light emitter and the two color light emitters are controlled so long as the respective light emission periods are approximately the same.

The luminous body is preferably provided at an end of an illumination unit (not shown) on which a light guide is laid, and irradiates the entire surface of the liquid crystal display device with the same phase.
In this case, irradiation light is supplied to the liquid crystal display device from a light emitter provided at an end of the illumination unit through a light guide.

At this time, the emission periods of the irradiation light corresponding to all the pixels (not shown) coincide. Therefore, it is very important to set the start of the light emission period to which area on the screen. Since the response of the liquid crystal is not completed in the display area where the light emission periods coincide immediately after scanning by the liquid crystal display device, the display one vertical period before is provided. Generally, it is preferable that the timing in the center portion of the liquid crystal display device is best displayed in accordance with the period from when the liquid crystal display near the center is completed to when scanning near the center starts. According to the above configuration, this timing can be changed according to the purpose of use of the liquid crystal display device.

The luminous bodies are divided into a plurality of regions having luminous periods of different phases with respect to the vertical synchronizing signal, and the luminous bodies having the same luminous periods collectively form a luminous group. The same area of the liquid crystal display device is illuminated, the areas of the different illuminated areas are substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction. Preferably, they are equally divided.

In the direct-type lighting device, the luminous body is divided into a plurality of regions having luminous periods of different phases with respect to the vertical synchronizing signal, and the luminous bodies having the same luminous period are collected. Illuminate the same area of the liquid crystal display device, illuminate the same area of the liquid crystal display device, the areas of the different illuminated areas are respectively substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction of the liquid crystal display device. Since the different phase difference equally divides one vertical period, it is possible to maintain a constant relationship between the scanning timing of the liquid crystal display device and the phase of the light emitting period of the irradiation area regardless of the display device. Therefore, it is possible to set a time zone in which the response of the liquid crystal is almost completed in all display areas to the light emission period.
Therefore, a display showing good contrast over the entire display area can be obtained.

It is preferable that the number of the luminous body groups is in the range of 4 to 48. If the number of light emitter groups is less than 4,
The portion where the phase shifts with respect to the scanning of the liquid crystal display device increases. When the number of illuminant groups is greater than 48, the number of cold cathode tubes is close to 100 (at least 48 × 2
= 96), which is not practical from the viewpoint of mounting technology and cost.

As described above, in the first liquid crystal display device of the present invention, at least one of the three primary colors of light is provided in the liquid crystal display device having a fixed period in which the luminance of the illumination device is reduced for each frame. Can be illuminated by an independent light-emitting body.

According to the second liquid crystal display device of the present invention, in the first liquid crystal display device, the phase of the waveform applied to the luminous body is
It is characterized by different emission colors.

According to a third liquid crystal display device of the present invention, in the first liquid crystal display device, the amplitude of the waveform applied to the luminous body is
It is characterized by different emission colors.

The fourth liquid crystal display device of the present invention is characterized in that, in the first liquid crystal display device, the pulse width of the waveform applied to the luminous body is made different depending on the emission color.

A fifth liquid crystal display device according to the present invention is characterized in that, in the first liquid crystal display device, a cold cathode tube is used as a luminous body of the lighting device.

A sixth liquid crystal display device according to the present invention is characterized in that, in the first liquid crystal display device, a hot cathode tube is used as a luminous body of the lighting device.

A seventh liquid crystal display device according to the present invention is characterized in that, in the above first liquid crystal display device, an electroluminescent element is used as a luminous body of a lighting device.

An eighth liquid crystal display device according to the present invention is the first or fifth liquid crystal display device, wherein a cold cathode tube is used as a luminous body of the illuminating device, and a cold cathode tube using a green phosphor is provided. It is characterized by having a cold cathode tube using two blue phosphors.

A ninth liquid crystal display device according to the present invention is the same as any one of the first to fourth liquid crystal display devices, wherein the illuminator of the illuminating device uses a cold cathode tube as a light emitter, and a cold cathode tube in which a green phosphor is sealed. , And a cold cathode tube enclosing a red phosphor and a cold cathode tube enclosing a blue phosphor.

The tenth liquid crystal display device of the present invention is characterized in that:
Alternatively, in the ninth liquid crystal display device, a green cold cathode tube is set to have a light emission period earlier than other cold cathode tubes.

The eleventh liquid crystal display device according to the present invention is directed to the eighth liquid crystal display device.
Alternatively, in the ninth liquid crystal display device, the green cold cathode tube is quenched or dimmed earlier than other cold cathode tubes.

The twelfth liquid crystal display device of the present invention is characterized in that
In a liquid crystal display device, a green cold cathode tube, a red cold cathode tube,
It is characterized by emitting light at an earlier timing in the order of blue cold cathode tubes.

A thirteenth liquid crystal display device according to the present invention is characterized in that
In a liquid crystal display device, a green cold cathode tube, a red cold cathode tube,
It is characterized in that light is extinguished or dimmed at an earlier timing in the order of blue cold cathode tubes.

The fourteenth liquid crystal display device of the present invention provides the ninth liquid crystal display device.
The liquid crystal display device is characterized in that a blue cold cathode tube emits light at the latest timing.

The fifteenth liquid crystal display device of the present invention is characterized in that
The liquid crystal display device is characterized in that the blue cold cathode tube is quenched or dimmed at the latest timing.

The sixteenth liquid crystal display device of the present invention is characterized by comprising a cold cathode tube enclosing green and red phosphors and a cold cathode tube enclosing only blue phosphor.

A seventeenth liquid crystal display device according to the present invention is characterized in that, in the sixteenth liquid crystal display device described above, the cold cathode tubes in which green and red phosphors are sealed emit light at an early timing.

An eighteenth liquid crystal display device according to the present invention is characterized in that, in the sixteenth liquid crystal display device, the cold cathode tubes in which green and red phosphors are sealed are quenched or dimmed at an early timing.

According to the nineteenth liquid crystal display device of the present invention, in the sixteenth liquid crystal display device described above, the response period of the cold-cathode tube in which only the blue phosphor is sealed is reduced, so that the light emission period can be delayed. It is characterized by.

The twentieth liquid crystal display device of the present invention is characterized in that, in the sixteenth liquid crystal display device described above, the pulse width is changed according to the emission color.

According to the first to twentieth liquid crystal display devices, it is possible to reliably improve the display quality of high-speed moving images without causing a coloring phenomenon.

[0146]

As described above, according to the liquid crystal display device of the present invention, at least one of the three primary colors of light is provided in the liquid crystal display device provided with a period in which the luminance of light applied to the pixel is reduced for each vertical period. It is characterized by having a luminous body that independently emits one color.

According to the above-described invention, light is irradiated on the pixels to display desired information. At this time, by providing a period in which the luminance of light applied to the pixel is reduced for each vertical period, only a moment having a high contrast ratio remains as an afterimage for a viewer, so that a clear screen with a good contrast ratio is seen. .

However, the luminous body is generally of a white type. In this case, phosphors of at least three colors corresponding to the three primary colors of light are encapsulated. A coloring phenomenon was observed, and as a result, the display quality was reduced. This is because the response time of the luminous body is different for each color, and as a result, the phase of the luminous waveform is different.

In view of the above, according to the above invention, a luminous body which independently emits at least one of the three primary colors of light is provided. By adjusting the phase of the light emission waveform from the light emitter, the phases of the light emission waveforms of the three primary colors of light can be brought closer to each other. Therefore, the phenomenon in which the outline of the image is colored in the high-speed moving image, which has occurred in the case of the white-type light-emitting body, is reduced, and the display quality can be significantly improved in the high-speed moving image. Play.

It is preferable that the luminous body which independently emits at least one color emits only green light among the three primary colors. Of the light emission waveforms of the three primary colors of light, green has the slowest change in waveform. Therefore, by independently providing the luminous body that emits only green light, the phase of the green luminous waveform from this luminous body can be adjusted, so that the phases of the luminous waveforms of the other two primary colors can be brought close to each other. . The other two primary colors may be configured to emit light from another illuminant, or may be configured to provide a separate illuminant for each primary color. By providing a separate illuminant for each primary color,
In addition, there is an effect that the phases can be adjusted with higher precision so as to approach each other.

It is similarly preferable that the luminous body which independently emits at least one color emits only blue light among the three primary colors. This is because the phosphor having the shortest response time is blue, and the response time of the green phosphor can be reduced to substantially the same time as that of red by material development.

It is preferable that the light emitting device further includes a light emission control means for controlling at least one of a period during which the light luminance is not reduced and an amplitude of the light luminance. By controlling the period during which the brightness of the light is not reduced, the waveform width of the light emission waveform can be controlled, and the phases of the light emission waveforms can be closer to each other with higher accuracy. Also, by controlling the amplitude of the luminance of the light, the light emission timing can be similarly adjusted, so that the phases of the light emission waveforms can be brought closer to each other. Further, by adjusting both the period in which the luminance of light is not reduced and the amplitude of the luminance of light, the effect of adjusting the light emission timing with higher accuracy can be achieved.

As described above, another liquid crystal display device according to the present invention has a plurality of cold-cathode tubes in which phosphors are sealed and which irradiates pixels with light according to drive signals, and the above-described structure is provided for each vertical period. Light-emission control means for controlling the drive signal so that the rate of change of the luminance of the cold-cathode tube with respect to time substantially coincides with the rate of change of luminance of the other cold-cathode tubes near the rise time and the fall time; At least one of the cathode tubes is filled with only a phosphor of one of the three primary colors of light, and a driving signal applied to the cold cathode tube is controlled by the light emission control means. .

According to the above-described invention, light is emitted to the pixels to display desired information. At this time, the drive signal is controlled by the light emission control means so that the luminance of the light irradiated to the pixel for each frame decreases near the rise and fall. By providing the period in which the brightness of the light is reduced in this way, only a moment having a high contrast ratio remains as an afterimage for a viewer, so that a clear screen with a good contrast ratio is seen.

However, in general, at least three color phosphors emitting green, red and blue light are sealed in the cold cathode tube. This phosphor emits fluorescence with ultraviolet rays emitted by mercury excited by discharge in the cold cathode tube. When the cold-cathode tubes are turned on and off in a pulsed manner, the phases of the light emission waveforms of the respective colors are different (response times required for light emission of the respective cold-cathode tubes are different). As described above, the phenomenon that the outline of the image is colored in the high-speed moving image due to the difference in the phase of the emission waveform is observed, and as a result, the display quality is deteriorated.

Therefore, according to the present invention, at least one of the cold-cathode tubes is filled with only a phosphor of one of the three primary colors of light, and a driving signal applied to this cold-cathode tube is Since the control is performed by the light emission control means, the phases of the light emission waveforms of the respective colors can be adjusted so as to approach each other.
Therefore, the phenomenon that the outline of the image is colored in the high-speed moving image is reduced, so that the display quality of the high-speed moving image can be significantly improved.

The cold cathode tube comprises two cold cathode tubes, one of which contains only the green phosphor of the three primary colors of light, and the other one of the three primary colors of light. It is preferable that the red and blue phosphors are enclosed.

In the emission waveform, among the three primary colors of light, green rises and falls particularly slowly. Therefore, a cold-cathode tube containing only green phosphors and a cold-cathode tube containing red and blue phosphors are provided independently, and the drive signal of each cold-cathode tube is controlled by the light emission control means. By changing the phase of the emission waveform of the cold-cathode tube (the cold-cathode tube in which the green phosphor is sealed) with the slowest emission waveform change, It is possible to make adjustments closer to higher precision.
As a result, the phenomenon in which the outline of the image is colored in the high-speed moving image can be reduced, and the display quality can be further improved.

The above-mentioned cold cathode tube is composed of two cold cathode tubes,
It is preferable that one of them has green and red phosphors among the three primary colors encapsulated therein, and the other has only blue phosphors among the three primary colors encapsulated therein.

In the emission waveform, the response time required for emission or dimming of blue light is particularly short. Therefore, the light emission periods of the blue and other colors of the cold-cathode tubes can be substantially matched by enclosing the blue and other colors in independent cold-cathode tubes and controlling them independently. This makes it possible to reduce the coloring of the outline in the high-speed moving image.

The cold-cathode tube comprises first to third three cold-cathode tubes, and the first cold-cathode tube contains only a green phosphor among the three primary colors of light. Only the red phosphor of the three primary colors of light is sealed in the second cold cathode tube, and only the blue phosphor of the three primary colors of light is sealed in the third cold cathode tube. It is preferred that

According to the above-described invention, the driving signals of the three cold cathode tubes are controlled by the light emission control means, respectively, as compared with the case where the two cold cathode tubes are used. The phases can be close to each other, and the phenomenon that the outline of the image is colored in the high-speed moving image can be more reliably reduced, and the display quality can be further improved.

In the above-mentioned liquid crystal display device, the phenomenon that the outline of an image in a high-speed moving image is colored is reliably reduced.
In order to improve the display quality, it is preferable that the emission control means controls the driving signal of each cold cathode tube at the following timing.

That is, the light emission control means performs the first
Each drive signal is controlled so that the cold-cathode tube emits light earlier than other cold-cathode tubes.

Alternatively, the light emission control means controls each of the drive signals so that the first cold-cathode tube is dimmed earlier than the other cold-cathode tubes.

Alternatively, the light emission control means controls the drive signals so as to emit light at an earlier timing in the order of the first cold cathode tube, the second cold cathode tube, and the third cold cathode tube.

Alternatively, the light emission control means controls each of the drive signals so that the first cold cathode tube, the second cold cathode tube, and the third cold cathode tube are dimmed at an earlier timing.

Alternatively, the light emission control means controls each drive signal so that the third cold cathode tube emits light at a timing later than the other cold cathode tubes.

Alternatively, the light emission control means controls each of the drive signals so that the third cold cathode tube dims at a later timing than the other cold cathode tubes.

In order to solve the above problems, the illumination device according to the present invention illuminates the pixels of the liquid crystal display device, and the light emission luminance of the light emission period is set at a certain phase with respect to the vertical synchronizing signal. And a dimming period, wherein the dimming period is in the range of 10% to 90% of one vertical period, and the light emitting period and the dimming period of at least one of the three primary colors of light are independently set. It is characterized by controlling.

When the dimming period is less than 10% of one vertical period, a portion having good contrast cannot be selectively used. On the other hand, if the dimming period is longer than 90% of one vertical period, the overall luminance is reduced, and a good image cannot be obtained. Therefore, in the above lighting device, the dimming period is set in a range of 10% to 90% of one vertical period. As a result, a portion having good contrast can be selectively used, and a good image can be obtained without lowering the overall luminance.

The dimming period is from 20% of the vertical period to 7%.
It is preferably in the range of 0%. If the dimming period exceeds 70%, a moving image display performance comparable to that of a CRT can be expected, so that the light should not be extinguished until the luminance is lost. Also, the dimming period is 2 compared to a general 1 candela (cd).
If it is 0%, the user can clearly feel the improvement of the moving image display performance.

The luminous body is preferably a cold cathode tube, electroluminescence or hot cathode tube. These luminous bodies are generally widely used,
Excellent in mass productivity and cost.

The luminous body preferably emits only green light among the three primary colors. The light emitter may emit only blue light among the three primary colors. Generally, green responds the least and blue responds the fastest. Therefore, by correcting the light emitter whose response time is farthest away (that is, the light emitter whose light emission period is out of phase), a preferable display can be obtained with a simple configuration.

The luminous body is composed of a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors and a second cold-cathode tube containing a phosphor having a relatively short response time. Is preferred. At present, a cold cathode tube as a luminous body is most excellent in industrial use in terms of cost and productivity. Therefore, the cold-cathode tube is divided into two groups, one of which is a luminous body group having a relatively long response time (a large phase shift), and the other being a light-emitting group having a relatively short response time (a small phase shift). By performing correction as a body group, it is possible to provide a display that is excellent in cost and productivity and practically practical.

It is preferable that a green phosphor is sealed in the first cold cathode tube and a red and blue phosphor is sealed in the second cold cathode tube. Green and red phosphors may be sealed in the first cold cathode tube, and blue phosphors may be sealed in the second cold cathode tube.

Generally, among the phosphors, green responds the slowest and blue responds the fastest. Therefore, by correcting the light emitter whose response time is farthest away (that is, the light emitter whose light emission period is out of phase), a preferable display can be obtained with a simple configuration.

The luminous body includes a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors and a second cold-cathode tube containing a phosphor having an intermediate response time. It is preferable to include a third cold cathode tube in which a phosphor having a short response time is sealed. In this case, since the three primary colors are divided into three cold-cathode tubes, the light emission periods of the respective colors can be aligned with higher accuracy, and the most favorable situation on display can be realized.

An inverter for driving the luminous body,
It is preferable that the phase, amplitude, or pulse width of an input signal to the inverter is modulated so that the light emission period and the light reduction period are independently controlled.

There are the following three factors to make the light emission period uniform. That is, the start time and end time of the light emitting period, the length of the light emitting period, and the luminance profile at the start and end of the light emitting period. The phase modulation controls the start time of the light emitting period, and the pulse width modulation controls the length of the light emitting period and the accompanying end time of the light emitting period. And
The amplitude modulation controls the luminance profile at the start and end of the light emitting period. Among them, the start time has the largest influence, and then the end time is followed by the profile.

It is preferable that the light emitting period of the first cold cathode tube be controlled independently and be controlled to substantially coincide with the light emitting period of the second or third cold cathode tube. The light emission period of the second cold cathode tube or the third cold cathode tube is
It may be controlled independently and controlled so as to substantially coincide with the light emission period of the first cold cathode tube.

In principle, the luminous body has a waiting time of 0, and the luminous period corresponding to the control signal starts and ends.
This is preferable for faithfully reproducing the intended display. However, in reality, a response time of 0 cannot be realized. Also,
In some cases, a high voltage circuit or a phase adjustment circuit, which is unnecessary in the past, may be required just to advance the phase.

Therefore, it is practical to make the light emitting periods of the cold cathode tubes substantially coincide with each other by correcting the luminous bodies (the second and third cold cathode tubes) having relatively advanced phases. In this case, it is practical and effective to positively correct a longer response time and a larger phase shift to make the light emission periods of the cold cathode tubes substantially coincide with each other. Such correction can be made, for example, by delaying the phase.
The circuit for delaying the phase can often be realized by a relatively simple adjustment circuit. Therefore, it is possible to avoid complicating the configuration.

It is preferable that the light emission periods of the first, second, and third cold cathode tubes are controlled independently of each other, and are controlled so that the light emission periods substantially coincide with each other. By independently controlling the three cold-cathode tubes, the most preferable display can be surely obtained.

It is preferable that only the green phosphor is sealed in the first cold cathode tube. Green and red phosphors may be sealed in the first cold cathode tube. When two cold cathode tubes are provided, the illuminant having the largest phase shift should be controlled independently. That is, since the phosphor having the slowest response time is generally green and the phosphor having the fastest response is blue, the phase shift can be reliably reduced by enclosing the phosphor of any one color alone. . The desired effect described above can be obtained if the light emission periods of the one color light emitter and the two color light emitters are controlled so long as the respective light emission periods are approximately the same.

It is preferable that the cold cathode tube is provided at an end of an illumination unit in which light guides are spread, and irradiates the entire surface of the liquid crystal display device with the same phase. In this case, irradiation light is supplied to the liquid crystal display device through a light guide from a cold cathode tube provided at an end of the lighting unit.

At this time, the emission periods of the irradiation light corresponding to all the pixels coincide. Therefore, it is very important to set the start of the light emission period to which area on the screen. The display area in which the light emission period matches immediately after scanning by the liquid crystal display device is not completed because the response of the liquid crystal is not completed.
This provides a display one vertical period earlier. Generally, it is preferable that the timing in the center portion of the liquid crystal display device is best displayed in accordance with the period from when the liquid crystal display near the center is completed to when scanning near the center starts. According to the above configuration, this timing can be changed according to the purpose of use of the liquid crystal display device.

The cold-cathode tubes are divided into a plurality of regions having light-emission periods of different phases with respect to the vertical synchronizing signal. The same area of the liquid crystal display device is formed and illuminated. The areas of the different illuminated areas are substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction. Preferably, the periods are equally divided.

In a direct-type lighting device, the cold-cathode tube is
The cold-cathode tubes, which are divided into a plurality of areas having light emission periods of different phases with respect to the vertical synchronization signal and have the same light emission period, collectively form a group of light emitters and illuminate the same area of the liquid crystal display device. And the area of different irradiation areas is
Each phase is substantially equal, and the phases are sequentially shifted at substantially equal intervals along the scanning direction of the liquid crystal display device, and different phase differences equally divide one vertical period. It is possible to maintain a constant relationship between the phase of the light emitting period of the irradiation area and the phase of the light emitting period regardless of the display device. Therefore, it is possible to set a time zone in which the response of the liquid crystal is almost completed in all display areas to the light emission period. Therefore, a display showing good contrast over the entire display area can be obtained.

It is preferable that the number of the luminous body groups is in the range of 4 to 48. If the number of light emitter groups is less than 4,
The portion where the phase shifts with respect to the scanning of the liquid crystal display device increases. When the number of illuminant groups is greater than 48, the number of cold cathode tubes is close to 100 (at least 48 × 2
= 96), which is not practical from the viewpoint of mounting technology and cost.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a liquid crystal display device of the present invention.

FIG. 2 is a waveform diagram showing an example of a signal waveform of a main part for explaining the operation of the liquid crystal display device.

FIG. 3 is a block diagram illustrating a configuration example of another liquid crystal display device of the present invention.

FIG. 4 is a waveform chart showing an example of a signal waveform of a main part for explaining the operation of the liquid crystal display device of FIG. 3;

FIG. 5 is a waveform diagram showing a signal waveform example of a main part, in which a part of the signal waveform of FIG. 4 is changed.

FIG. 6 is a block diagram illustrating a configuration example of a liquid crystal display device in which a phenomenon occurs in which a contour of an image is colored in a high-speed moving image.

FIG. 7 is a waveform diagram for explaining the operation of the liquid crystal display device of FIG.

FIG. 8 is an explanatory diagram for defining light emission and dimming timings together with inverter input signal timings.

FIG. 9 is a block diagram showing another configuration example of the liquid crystal display device of the present invention.

FIG. 10 is a waveform chart showing an example of a signal waveform of a main part for describing an operation of another liquid crystal display device.

FIG. 11 is a waveform diagram showing that the light emission period is adjusted by delaying the response time in the present invention.

FIG. 12 is a block diagram illustrating a configuration example of a lighting device according to the present invention.

FIG. 13 is a waveform diagram showing a relationship among a light emission profile of a cold cathode tube of the lighting device, a vertical synchronization signal, and an inverter input signal.

14A is a front view of a configuration example of another lighting device according to the present invention, and FIG. 14B is a side view.

FIG. 15 is a block diagram illustrating a configuration of the lighting device in FIG. 14;

FIG. 16 is a waveform diagram showing that light emission periods of a plurality of light emitters are substantially matched by shifting a drive timing of a plurality of light emitters.

FIG. 17 is a waveform diagram illustrating an example in which a shift in a light emitting period of a plurality of light emitters is reduced in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inverter control circuit (light emission control means) 2a Inverter 2b Inverter 3a Cold cathode tube (light emitter, first cold cathode tube) 3b Cold cathode tube (light emitter, second cold cathode tube) 3c Cold cathode tube (light emitter, 3 cold cathode tube) 4 liquid crystal panel control circuit 5 liquid crystal panel 5a gate driver 5b source driver

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 3/36 G09G 3/36 H05B 41/392 H05B 41/392 M (72) Inventor Makoto Shiomi Osaka, Osaka, Japan 22-22 Nagaike-cho, Abeno-ku, Sharp F-term (reference) 2H091 FA42Z FD24 GA11 LA15 LA16 2H093 NA18 NC16 NC34 NC44 ND17 ND24 ND34 ND36 ND58 NE06 3K098 CC36 CC40 CC60 CC70 DD01 DD22 DD35 DD44 EE13EE28 AA01 AF44 AF71 BB11 BB29 EA01 FA16 FA29 FA54 FA56 5C080 AA10 BB05 CC03 DD03 EE19 EE30 JJ02 JJ04

Claims (45)

[Claims] In a liquid crystal display device provided with a period in which the luminance of light applied to a pixel is reduced for each vertical period, a light intensity of 3
A liquid crystal display device comprising a luminous body that independently emits at least one of the primary colors. 2. The liquid crystal display device according to claim 1, wherein said luminous body which independently emits at least one color emits only green light out of three primary colors. 3. The light-emitting device according to claim 1, further comprising a light-emission control unit for controlling at least one of a period during which the light luminance is not reduced and an amplitude of the light luminance. Liquid crystal display. 4. The liquid crystal display device according to claim 1, wherein said luminous body is a cold cathode tube, an electroluminescent device, or a hot cathode tube. 5. A plurality of cold-cathode tubes for enclosing a phosphor and irradiating pixels with light according to a drive signal, and the rate of change in luminance of the plurality of cold-cathode tubes with respect to time rises for each vertical period. Light-emission control means for controlling the driving signal so as to substantially coincide with each other in the vicinity of the time and the fall time, and at least one of the cold-cathode tubes is a phosphor of only one of the three primary colors of light. And a driving signal applied to the cold-cathode tube is controlled by the light emission control means. 6. A first and a second cold-cathode tube in which a phosphor is sealed and a pixel is irradiated with light according to a drive signal, and a change rate of the brightness of the cold-cathode tube with respect to time for each vertical period. Light-emission control means for controlling the drive signal so as to substantially coincide with each other in the vicinity of the rise time and the fall time, wherein the first cold-cathode tube is filled with only a green phosphor of the three primary colors of light. In addition, the second cold cathode tube is filled with red and blue phosphors of the three primary colors of light, and a drive signal applied to the first and second cold cathode tubes is controlled by the light emission control means. A liquid crystal display device, each of which is controlled. 7. A first to third cold-cathode tubes for enclosing a phosphor and irradiating a pixel with light according to a drive signal, and a rate of change of luminance of the cold-cathode tubes with respect to time for each vertical period. Light-emission control means for controlling the drive signal so as to substantially coincide with each other in the vicinity of the rise time and the fall time, wherein the first cold-cathode tube is filled with only a green phosphor of the three primary colors of light. In the second cold cathode tube, only the red phosphor of the three primary colors of light is sealed, and in the third cold cathode tube, only the blue phosphor of the three primary colors of light is enclosed. A liquid crystal display device, wherein a drive signal to be sealed and applied to the first to third cold cathode tubes is controlled by the light emission control means. 8. The light emission control means includes: the first cold cathode tube;
The liquid crystal display device according to claim 7, wherein each of the drive signals is controlled so that light emission timing is advanced in the order of the second cold cathode tube and the third cold cathode tube. 9. The light emission control means includes: the first cold cathode tube;
8. The liquid crystal display device according to claim 7, wherein each of the driving signals is controlled so that the dimming timing is advanced in the order of the second cold cathode tube and the third cold cathode tube. 10. The apparatus according to claim 7, wherein said light emission control means controls each of said drive signals so that the light emission timing of said third cold cathode tube is later than that of the other cold cathode tubes. Liquid crystal display. 11. The light emitting control means according to claim 7, wherein said light emission control means controls each of said drive signals such that the light emission timing of said third cold cathode tube is later than that of the other cold cathode tubes. Liquid crystal display device. 12. The method according to claim 1, wherein the illuminant emits only blue light among the three primary colors. 13. A first and a second cold-cathode tube in which a phosphor is sealed and a pixel is irradiated with light according to a drive signal, and a change rate of the brightness of the cold-cathode tube with respect to time for each vertical period. Light-emission control means for controlling the drive signal so as to substantially coincide with each other in the vicinity of a rise time and a fall time, wherein the first cold-cathode tube is filled with green and red phosphors of three primary colors of light. And the second cold cathode tube is
A liquid crystal display device, wherein only a blue phosphor of the three primary colors of light is sealed, and drive signals applied to the first and second cold cathode tubes are respectively controlled by the light emission control means. 14. The apparatus according to claim 6, wherein said light emission control means controls each of said drive signals such that light emission timing of said first cold cathode tube is earlier than that of other cold cathode tubes.
14. The liquid crystal display device according to 7 or 13. 15. The light emission control means controls each of the drive signals so that the dimming timing of the first CCFL is earlier than that of the other CCFLs.
14. The liquid crystal display device according to 7 or 13. 16. A driving method for a liquid crystal display device comprising a light emitting element which independently emits at least one of three primary colors of light by providing a period in which the luminance of light applied to a pixel is reduced for each vertical period. A method for driving a liquid crystal display device, comprising: controlling at least one of a period during which the luminance of light is not reduced and an amplitude of the luminance of light in the luminous body. 17. A plurality of cold-cathode tubes enclosing a phosphor and irradiating pixels with light according to a drive signal, wherein the change rate of the brightness of the plurality of cold-cathode tubes with respect to time is changed every one vertical period. What is claimed is: 1. A method of driving a liquid crystal display device, comprising: controlling a drive signal so as to substantially match near a rise time and a fall time, wherein at least one of the cold cathode tubes has one of three primary colors of light. A method of driving a liquid crystal display device, wherein only the phosphor is sealed and a drive signal applied to the cold cathode tube is controlled. 18. A fluorescent lamp is enclosed, and first and second cold-cathode tubes for irradiating pixels with light according to a drive signal are provided, and a change rate of the brightness of the cold-cathode tubes with respect to time for each vertical period. Is a driving method of a liquid crystal display device that controls the driving signal so that the first and second cold cathode fluorescent lamps substantially coincide with each other in the vicinity of a rise time and a fall time. Only, red and blue phosphors of the three primary colors of light are sealed in the second cold cathode tube, and drive signals applied to the first and second cold cathode tubes are controlled respectively. A method for driving a liquid crystal display device, comprising: 19. A fluorescent lamp is enclosed, and first to third cold-cathode tubes for irradiating pixels with light according to a drive signal are provided, and a change rate of the brightness of the cold-cathode tubes with respect to time for each vertical period. Is a driving method of a liquid crystal display device for controlling the driving signal so that the first and second cold cathode tubes substantially coincide with each other in the vicinity of a rising time and a falling time. Only the red phosphor of the three primary colors of light is encapsulated in the second cold cathode tube, and only the blue phosphor of the three primary colors of light is encapsulated in the third cold cathode tube. A method for driving a liquid crystal display device, comprising: enclosing and controlling drive signals applied to the first to third cold cathode tubes. 20. First and second cold-cathode tubes for enclosing a phosphor and irradiating pixels with light in accordance with a drive signal, and a change rate of the brightness of the cold-cathode tubes with respect to time for each vertical period. Is a driving method of a liquid crystal display device that controls the driving signal such that the first and second cold cathode fluorescent lamps substantially coincide with each other near a rise time and a fall time. Enclosing a phosphor, enclosing only the blue phosphor of the three primary colors of light in the second cold cathode tube, and controlling drive signals applied to the first and second cold cathode tubes, respectively; A method for driving a liquid crystal display device, comprising: 21. The liquid crystal according to claim 18, 19, or 20, wherein each of the drive signals is controlled so that the light emission timing of the first cold cathode tube is earlier than that of the other cold cathode tubes. A method for driving a display device. 22. The method according to claim 18, wherein the drive signals are controlled such that the dimming timing of the first CCFL is earlier than that of the other CCFLs. A method for driving a liquid crystal display device. 23. The first cold cathode tube, the second cold cathode tube,
20. The method according to claim 19, wherein the driving signals are controlled so that the light emission timing is advanced in the order of the third cold cathode tubes. 24. The first cold cathode tube, the second cold cathode tube,
20. The driving method according to claim 19, wherein the driving signals are controlled so that the dimming timing is advanced in the order of the third cold cathode tubes. 25. The driving method of a liquid crystal display device according to claim 19, wherein each of the driving signals is controlled such that the light emission timing of the third cold cathode tube is later than that of the other cold cathode tubes. . 26. A light source for irradiating a pixel of a liquid crystal display device, wherein the light emission luminance has a light emission period and a light reduction period at a certain phase with respect to a vertical synchronization signal, and the light reduction period is one. A lighting device, wherein the lighting period and the dimming period of at least one of the three primary colors of light are independently controlled in a range from 10% to 90% of the vertical period. 27. The lighting device according to claim 26, wherein said illuminant is a cold cathode tube, electroluminescence, or hot cathode tube. 28. The lighting device according to claim 26, wherein the illuminant emits only green light among the three primary colors. 29. The lighting device according to claim 26, wherein the illuminant emits only blue light among the three primary colors. 30. The luminous body comprises a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors and a second cold-cathode tube containing a phosphor having a relatively short response time. 27. The lighting device according to claim 26, wherein 31. The first cold-cathode tube encloses a green phosphor, and the second cold-cathode tube encloses red and blue phosphors. The lighting device according to claim 1. 32. A green phosphor and a red phosphor are sealed in the first cold cathode tube, and a blue phosphor is sealed in the second cold cathode tube. The lighting device according to claim 1. 33. A light-emitting body comprising: a first cold-cathode tube containing a phosphor having a relatively long response time among the three primary colors; a second cold-cathode tube containing a phosphor having an intermediate response time; 27. The lighting device according to claim 26, further comprising a third cold-cathode tube enclosing a phosphor having a relatively short response time. 34. An apparatus according to claim 30, further comprising an inverter for driving said luminous body, wherein the phase of an input signal to said inverter is modulated so that said luminescence period and said dimming period are independently controlled. The lighting device according to 31, 32, or 33. 35. An apparatus according to claim 30, further comprising an inverter for driving said luminous body, wherein the amplitude of an input signal to said inverter is modulated so that said light emission period and said dimming period are independently controlled. The lighting device according to 31, 32, or 33. 36. An apparatus according to claim 30, further comprising an inverter for driving said light emitter, wherein a pulse width of an input signal to said inverter is modulated, and said light emitting period and said light dimming period are independently controlled. 35. The lighting device according to claim 31, 32, or 33. 37. The light emitting period of the first cold cathode tube is controlled independently, and is controlled to substantially coincide with the light emitting periods of cold cathode tubes other than the first cold cathode tube. The lighting device according to 30, 31, 32, 33, 34, 35, or 36. 38. The light emission period of the second cold cathode tube or the third cold cathode tube is controlled independently, and
37. The lighting device according to 33, 34, 35, or 36, wherein the lighting device is controlled so as to substantially coincide with a light emitting period of the cold cathode tube. 39. The light-emitting periods of the first, second and third cold-cathode tubes are controlled independently of each other, and are controlled such that the light-emitting periods substantially coincide with each other. The lighting device according to claim 34, 35, or 36. 40. The apparatus according to claim 33, wherein only the green phosphor is sealed in said first cold cathode tube.
The lighting device according to 35, 36, 37, 38, or 39. 41. The first cold-cathode tube is filled with green and red phosphors.
The lighting device according to 4, 35, 36, 37, 38, or 39. 42. The cold cathode tube is provided at an end of a lighting unit on which a light guide is laid, and irradiates the entire surface of the liquid crystal display device with the same phase.
The lighting device according to claim 1. 43. The liquid crystal display according to claim 30, wherein the cold cathode tubes are provided perpendicular to the scanning direction of the liquid crystal display device.
42. The lighting device according to any one of items 41 to 41. 44. The cold-cathode tube is provided divided into a plurality of regions having light-emitting periods of different phases with respect to the vertical synchronization signal, and the cold-cathode tubes having the same phase of light-emitting period are collectively arranged as a light-emitting element. A group is formed to irradiate the same area of the liquid crystal display device, the areas of the different irradiation areas are respectively substantially equal, and the phases are sequentially shifted at substantially equal intervals along the above-mentioned scanning direction. 44. The lighting device according to claim 43, wherein one vertical period is equally divided. 45. The lighting device according to claim 44, wherein the number of the luminous body groups is in a range of 4 to 48.