JP2001272652A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance display quality and the like in a display device in the system of illuminating a light valve of LCD and the like by using a back light. SOLUTION: The display device is provided with the light valve 103 displaying a color image based on a space additive color mixture by plural pixels arranged in a two-dimensional matrix, the back light 101 illuminating the light valve 103 and a shutter 102 provided between the light valve 103 and the back light 101 and consisting of plural regions capable of independently driving and so constructed that the transmission and the interception of illumination light from the back light 101 can be switched timewisely. The light valve 103 and the shutter 102 are preferably constituted of a liquid crystal light valve and a liquid crystal shutter, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a display device, and more particularly to a display device using liquid crystal.

[0002]

2. Description of the Related Art A liquid crystal display (LCD), whether of a direct-view type or a projection type, applies a voltage corresponding to an image to a liquid crystal for each pixel through a thin film transistor or the like provided for each pixel, thereby obtaining a desired liquid crystal. It is a two-dimensional transmission type light valve for displaying images, and has a backlight behind it, except for a reflection type LCD using ambient light for illumination and a part of projection type LCD using a reflection type liquid crystal light valve. It has a structure.

Switching of image display is performed by updating the voltage value applied to each pixel for each frame. In order to prevent image sticking due to DC application to the liquid crystal, the polarity of the applied voltage is usually inverted even for the same image data, and the voltage value held in the pixel is updated. The update of the holding voltage is usually performed for each line or for each pixel dot, and the pixels other than the updating are holding the voltage value written (updated) in the previous frame. The backlight provided on the back of the liquid crystal light valve is a fluorescent lamp for direct-view flat type, a metal halide lamp, high-pressure mercury lamp or halogen lamp for projection type. Is irradiated.

In recent years, the response speed of the liquid crystal has been improved, and the screen has been switched in a shorter time than in the past, and characteristics suitable for displaying moving images have been obtained. However, it has been pointed out that the above-described LCD screen updating method is essentially inferior in moving image display quality as compared with CRT display. That is, as a cause of deterioration of moving image display quality, a screen is always displayed and image data is sequentially switched as compared with a CRT display method in which light is emitted only during electron beam scanning and black display is performed in other periods. It is believed that some LCD display methods have a cause (Ishiguro et al., IEICE technical report EID96-4 (1996) p19.).

[0005] As a solution to the above problem, an OCB (optically compensated) has been proposed.
Birefringence) and a high-speed LCD combined with an LED backlight that can be turned on at high speed.
A method in which a backlight emits pulses (Taira et al.,
AM-LCD '98 (1998) p113. ), OCB
A driving method in which a half field is set to a black display period in a cell (Nakamura et al., Journal of Liquid Crystal Society, Vol. 3-2 (199)
9) p99. ) Has been proposed.

[0006] However, the former method has a problem that it is difficult to perform pulsed light emission with a light source such as a cold cathode fluorescent tube which is usually used due to light emission and afterglow. In the latter method, the screen must be updated twice in one frame period. When the number of pixels increases, such as SXGA and UXGA, the number of lines that need to be updated increases. There is a problem that the writing (updating) period per line is shortened and driving becomes difficult. None of these methods can solve the problem of screen bleeding in moving images.

[0007]

As described above, the ordinary L
Since a screen is always displayed on a CD, a problem of blurring in a moving image occurs, and there is a problem that display quality is inferior to that of a CRT.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. In a display device in which a light valve such as an LCD is illuminated by a backlight, the problem of blurring in a moving image is solved. The aim is to further improve the

[0009]

A display device according to the present invention comprises a light valve for displaying a color image based on a spatial additive color mixture by a plurality of pixels arranged in a two-dimensional matrix, and a light for illuminating the light valve. And a shutter, which is provided between the light valve and the light, and includes a plurality of independently drivable regions configured to temporally switch between transmission and blocking of illumination light from the light. It is characterized by the following.

In the above invention, it is preferable that the light valve is constituted by a liquid crystal light valve, and the shutter is constituted by a liquid crystal shutter.

In the above invention, the light comprises a plurality of light sources corresponding to a plurality of independently drivable areas of the shutter, and each light source is turned on and off in accordance with a transmission and blocking operation in a corresponding area of the shutter. It is preferable that the device be turned off.

In the invention, it is preferable that the transmission and blocking operations in each of the independently drivable regions of the shutter correspond to a screen updating operation in a corresponding region of the light valve.

According to the present invention, a shutter is provided between a light valve and a light such as a backlight, and the shutter is constituted by a plurality of independently drivable areas. Since the cutoff can be switched in time, the switching operation of transmission and cutoff in each area is associated with the turning on / off operation of each light source of the light or the screen updating operation of the corresponding area of the light valve (synchronized). )be able to. Therefore, by associating the operation of switching between transmission and cutoff with the operation of turning on and off the light, it is possible to improve the display quality and reduce the power consumption. In addition, by associating the operation of switching between transmission and blocking with the operation of updating the screen of the light valve, the corresponding area of the shutter can be kept in a blocking state during the transient response period of the liquid crystal or the like used for the light valve. Display quality can be improved.

Further, the display device according to the present invention is configured such that a liquid crystal layer is interposed between opposing substrates provided with polarizing plates, and a color image is formed by a plurality of pixels arranged in a two-dimensional matrix based on spatial additive color mixture. A liquid crystal light valve to display,
A light for illuminating the liquid crystal light valve, and a liquid crystal layer is interposed between a counter substrate having a polarizing plate, and is provided between the liquid crystal light valve and the light to transmit illumination light from the light and A liquid crystal shutter configured to temporally switch the cutoff, wherein a polarizing plate on the liquid crystal shutter side of the liquid crystal light valve and a polarizing plate on the liquid crystal light valve side of the liquid crystal shutter are shared. And

According to the present invention, the liquid crystal shutter is provided between the liquid crystal light valve and the light, and the liquid crystal light valve and the polarizing plate of the liquid crystal shutter are shared, thereby simplifying the structure and reducing the number of parts. be able to.

The light valve described here performs spatial additive color mixture in order to display a color image. In other words, a desired color image is displayed by dividing one picture element into three pixels and providing each pixel with an RGB color filter.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing specific embodiments, preferred embodiments of the present invention will be described below.

The light valve of the present invention may be any transmittance modulation element capable of two-dimensionally displaying image information in real space by controlling the transmittance of incident light. Thin film transistor (T
An active matrix driven transmission type liquid crystal display device having FT) is most desirable as such a light valve.

Further, since the liquid crystal light valve used in the present invention is intended for displaying moving images, it is desirable to use a liquid crystal mode capable of displaying high-speed response and halftone. For example, a thresholdless antiferroelectric liquid crystal, a polymer ferroelectric liquid crystal, a polymer liquid crystal having ferroelectric or antiferroelectric properties,
Photocurable polymer stabilization mode, narrow gap TN, OC
B, vertical alignment (VA) cell, π twist cell, homogeneous alignment cell, transmission scattering liquid crystal (PDLC), BTN,
Various modes such as GH driven by two frequencies can be used.
The response time required for these liquid crystal operation modes is a value that can respond within one frame period (1 / 60s = 1).
6.7 ms).

The shutter according to the present invention is provided for the purpose of temporally switching the transmission / non-transmission state of the illumination light. A liquid crystal shutter capable of high-speed switching is desirable as its mode, and the liquid crystal operation modes thereof are ferroelectric liquid crystal, antiferroelectric liquid crystal, ferroelectric or antiferroelectric polymer liquid crystal, and photocurable polymer stable. Mode, narrow gap T
N, OCB, π twist cell, homogeneous alignment cell,
BTN, two-frequency driving GH, and transmission scattering type liquid crystal can be used. These liquid crystal modes may be controlled by binary, and may have a hysteresis characteristic.

In the case of the liquid crystal mode in which a polarizing plate is used for both the liquid crystal light valve and the liquid crystal shutter, the analyzer of the liquid crystal shutter can be shared with the incident side polarizing plate of the liquid crystal light valve.

When the response time from transmission to non-transmission and from non-transmission to transmission is different, as is often seen in nematic liquid crystals such as OCB and π twist cell, the response time from non-transmission to transmission state is different. It is more desirable to set the operation mode so as to shorten the time. For example, O-type liquid crystal
When configuring a CB, a normally black operation mode is a more desirable mode than a normally white operation mode.

Further, in order to improve the coloring and visual characteristics of the liquid crystal shutter, a retardation film is provided to compensate for the retardation of the liquid crystal shutter, so that the transmission wavelength characteristics are made uniform and the contrast at the time of oblique viewing is increased. Is more desirable.

Further, it is more desirable to use a film substrate in order to reduce the weight of the display device, and PES, PC, TAC, etc. can be used as the substrate material.

The liquid crystal shutter is switched by segment driving, and switching between transmission and non-transmission is performed in synchronization with the image update of the liquid crystal light valve. That is, image writing to the liquid crystal light valve is performed from the upper part to the lower part of the screen line by line, and during that period, the liquid crystal shutter is in the non-transmission state. After the display responds to the new display from the display of the previous frame, the liquid crystal shutter enters the transparent state,
The image is viewed by the observer. Although these operations may be performed collectively on the entire screen, the so-called scroll operation, in which the liquid crystal shutter is divided into a plurality of regions and a switching operation is performed for each of a plurality of lines, is more effective in writing time and response time. It is desirable in terms of securing margins.

In the case of a still image display, if the liquid crystal shutter is always kept in the transmissive state, the illumination efficiency from the light source is improved, so that the power consumption of the backlight can be reduced. Switching between a still image display and a moving image display can be distinguished by an image signal or a control signal input to the liquid crystal light valve, so that automatic switching of the operation based on the displayed image is easy. A similar switching operation is performed in a mobile display device or the like where there is a great demand for power consumption reduction.
It is effective to perform switching between the operation of the external power supply and the operation of the battery.

Since the backlight is basically a temporally steady illumination, a flat backlight using a conventional cold cathode tube, a metal halide lamp, a high-pressure mercury lamp, or the like can be used. However, when the operation of the liquid crystal shutter is switched according to the still image display and the moving image display as described above, the display of the still image has a duty of 100%, whereas the display of the moving image has a duty of 100% or less (10 to 70%).
%), It is necessary to increase the light emission luminance when displaying a moving image according to the duty.

In the case of a light source such as an LED or a cold-cathode fluorescent tube, which can be easily relighted, and a plurality of (light) light sources are provided for illumination, the light sources are arranged corresponding to the area dividing direction of the liquid crystal shutter. By turning on / off the light in synchronization with the operation of the liquid crystal shutter, it is possible to further reduce power consumption. In this case, even if the light-emitting time and the afterglow time of the light source are longer than the case where the light-on / light-off operation is performed only by the light source without using the liquid crystal shutter, the light is blocked by the liquid crystal shutter, so that interference is less likely to occur. There are benefits.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a view showing a structure of a display device according to a first embodiment when viewed from a lateral direction.

The display device of this embodiment is a direct-view type flat display device, and includes a backlight 101, a liquid crystal shutter 10
2. TFT-LCD 103 which is a liquid crystal light valve
Consisting of parts.

The backlight 101 is a normal flat-type sidelight type backlight, in which a cold cathode fluorescent tube 104 as a light source is disposed adjacent to a light guide plate 106, and a reflector 105, a reflection plate 107, a condensing / diffusing light source. Sheet 108
It has.

The liquid crystal shutter 102 has a polarizing plate 109 and applies a voltage to the liquid crystal layer 110 held between a pair of opposing PES film substrates 111 via an ITO transparent electrode (not shown). The liquid crystal alignment state is controlled, and the transmission state is switched by polarization modulation.

The TFT-LCD 103 is a normal active matrix type liquid crystal display panel based on the same driving display as in the TN mode or the like, but the liquid crystal layer 113 held between a pair of transparent substrates 114 facing each other has a TN mode. For example, an OCB mode capable of responding at a higher speed than is used.
In addition, of the pair of opposing polarizing plates 112 and 115,
The incident-side polarizing plate 112 of the TFT-LCD 103 also serves as an analyzer of the liquid crystal shutter 102.

FIG. 2 shows a liquid crystal shutter 1 according to this embodiment.
It is a figure explaining the optical arrangement of No. 02. The liquid crystal used for the liquid crystal shutter is a ferroelectric polymer liquid crystal, and has a positive voltage +
When V ₀ and a negative voltage −V ₀ are applied, switching is performed such that the fast axes F have an angle of 45 degrees with each other. The polarization axes (transmission axis or absorption axis) P of the polarizing plates 109 and 112 are arranged orthogonally (crossed Nicols), and one of the polarization axes is aligned with the fast axis F of the liquid crystal layer 110 when the -V ₀ voltage is applied. I do.

FIG. 3 shows a voltage-transmittance characteristic and a transmittance wavelength characteristic in the liquid crystal shutter of this embodiment.

FIG. 3A shows the voltage (V) of the liquid crystal shutter.
-It shows transmittance (T) characteristics. In the present liquid crystal operation mode, the liquid crystal has a hysteresis characteristic near ₀ V, but does not have the hysteresis characteristic at the operating point ± V ₀ , and the transmission characteristic is almost saturated. FIG. 3B shows a wavelength characteristic of the transmittance. By adopting the optical arrangement described above, the polarization plane rotates 90 degrees in the white (transmission) display state, and goes straight in the black (non-transmission) display state. Here, the retardation of the liquid crystal is set to be around 550 nm where the visibility is twice the highest. Therefore, a high-contrast shutter operation with small wavelength dispersion is possible. Although not particularly shown, in the present liquid crystal operation mode, by setting the voltage at about V ₀ = 20 V, a sufficiently high-speed switching with a response time of about 1 ms can be obtained.

FIG. 4 is a diagram showing a driving sequence in this embodiment. The horizontal axis is time, and TFT-LCD1
3 shows a drive sequence and a response waveform of the liquid crystal, and a drive sequence and a response waveform of the liquid crystal shutter 102.

In FIG. 4, a TFT-LCD is provided with a writing period 401 and a holding period 402 within one field period, and a voltage value V ₀ having the same positive and negative polarity is applied to the liquid crystal shutter for the same period. Is done.

First, in the TFT-LCD, a writing operation is sequentially performed for each line within a period of 50% or less of one field period.
As shown by 4, the response is made in the first half of the writing period. On the other hand, the response waveforms of the pixels at the bottom of the screen are as shown by waveforms 405 and 406, and after the writing period 401, the liquid crystal enters a holding state after a transient response period.

The liquid crystal shutter operates for 50 times of one field period including the writing period 401 and the transient response period at the bottom of the screen.
%, The non-display state 409 is set by the negative polarity voltage application 407, and the positive polarity voltage application 408 is set in the latter half of the TFT-LCD when all the pixels have reached the holding period.
Causes the display state. Here, since the response time of the liquid crystal shutter is shorter than that of the TFT-LCD that performs a response including halftone, the display state is promptly established. By taking such an operation mode, a pseudo pulsed light emission display can be performed without displaying the transient response state of the TFT-LCD, and the display quality at the time of displaying a moving image is improved.

Here, in order to prevent image sticking of the liquid crystal shutter, the voltage application periods 407 and 408 must be equally divided. Also, TF is set within the first half field period.
It is necessary that the writing and response of the T-LCD have been completed, but this relationship is not strict as compared with the voltage application time to the liquid crystal shutter, and the relationship is not significant in the transient response state of about 40 to 50%. Even when switching from the display to the display state, sufficient display quality can be obtained. Further, in the present embodiment, since the display period has a duty of 50%, it is necessary to increase the luminance of the liquid crystal backlight to twice that of the related art.

FIG. 5 is a diagram schematically showing a display state when a moving image is displayed in this embodiment. FIG.
In (a), the liquid crystal shutter is in a transmission state, and the TFT
-The image written on the LCD is displayed. Thereafter, in the first half of the next field period, FIG.
As shown in (1), the liquid crystal shutter is in a non-transmission state, that is, the entire screen is in a black display state. Thereafter, in FIG. 5C, the image written during the period of FIG. 5B is displayed. With such a display mode, blurring of a moving image does not occur, and display quality can be improved.

(Embodiment 2) FIG. 6 is a view showing the structure of a display device according to a second embodiment. The features of this embodiment are as follows.
The liquid crystal shutter 102 is divided into a plurality of screen areas 601 to 605 and can be driven independently. Other basic structures are the same as those in the first embodiment.

FIG. 7 is a diagram showing a driving sequence of the present embodiment. Driving sequence 7 of TFT-LCD 103
01 to 705 respectively correspond to the divided regions 601 to 605 of the liquid crystal shutter 102 as viewed from the observer. Driving sequence 7 of TFT-LCD 103
01 to 705, the writing period is set to 701a to 701.
5a, the transient response period is indicated by 701b to 705b, and the holding period is indicated by 701c to 705c. The non-display state in each of the divided areas 601 to 605 of the shutter 102 is denoted by 601a to 605a, and the display state is denoted by 601.
1b to 605b, respectively.

In this embodiment, since the liquid crystal shutter is divided into a plurality of areas, the writing sequence of the TFT-LCD extends from 701 to 705 throughout the one field period. In each region, the sum of the writing period (for example, 701a) and the transient response period (for example, 701b) in the TFT-LCD corresponds to the non-display period (for example, 601a) of the corresponding region in the liquid crystal shutter.

This makes it possible to increase the writing time per line, which is suitable for high-precision multi-pixel display. Further, by increasing the number of divisions of the liquid crystal shutter, the writing period per area is shortened, so that the ratio of the transient response period can be increased.
The required characteristics of the response characteristics of the liquid crystal mode used for the TFT-LCD can be relaxed.

In the first and second embodiments, for example, an operation mode of a liquid crystal shutter exhibiting a voltage-transmittance characteristic as shown in FIG. 8, for example, a polymer stabilized ferroelectric liquid crystal by photopolymerization is used. It is clear that the same effect can be obtained even if there is. That is, the response characteristics and transmission wavelength characteristics at the operating point ± V ₀ are important, and the history of the optical response and the operation mode of the liquid crystal are not particularly limited.

(Embodiment 3) FIG. 9 is a diagram schematically showing a driving sequence in a third embodiment. TFT-
The drive sequence of the LCD 103 is changed to 901 and 902 (writing periods 901a and 902a, a transient response period 901b
And 902b, and holding periods 901c and 902c), the driving waveforms of the liquid crystal shutter 102 are changed to 903 and 904 (non-display states 903a and 904a, display states 903b and 903).
4b).

The structure of this embodiment is almost the same as that of FIG.
The liquid crystal shutter employs an operation mode of a nematic liquid crystal. However, although not specifically shown, G
In an operation mode such as an H mode or a transmission scattering mode that uses a nematic liquid crystal material and does not require a polarizing plate, the incident side polarizing plate of the liquid crystal shutter is not required.

The basic operation of this drive sequence is the same as that of the second embodiment, but the specific voltage waveform applied to the liquid crystal shutter is different because a nematic liquid crystal mode is used. That is, the operation of the liquid crystal shutter uses a normally black mode as shown in FIG. 10A, and is non-transmissive by no voltage application (0 V) and AC voltage application (± V ₀ ) as shown in FIG. 10B. / Transmission state is selected. Therefore, in these nematic liquid crystal operation modes, the duty ratio in the non-display / display state can be freely set.

In this embodiment, a normally black mode in which the display is switched to the display state promptly when the updating of the image is completed is preferable. For example, these shutters are used when a still image / moving image is displayed or when an external power supply / battery is operated. When the operation is switched, a normally white mode in which power is not particularly consumed is suitable for setting a transmission state in a still image display.

Although the present embodiment is suitable for a nematic liquid crystal, for example, some smectic liquid crystals such as a thresholdless antiferroelectric liquid crystal mode having a voltage-transmittance characteristic as shown in FIG. In this case, a similar drive sequence may be used depending on the flipping characteristics of the alignment state at the time of polarity reversal.

(Embodiment 4) FIG. 12 is a diagram schematically showing a driving sequence in a fourth embodiment of the present invention. In this embodiment, a drive sequence suitable for an antiferroelectric liquid crystal mode having a voltage-transmittance characteristic as shown in FIG. 11 is shown.

In the liquid crystal operation mode having a voltage-transmittance characteristic as shown in FIG. 11, a transmission state occurs when ± V _{0 is} applied, and a non-transmission state occurs when no voltage is applied (0 V). Therefore, in order to prevent burn-in, the first field 1200a (writing period 1201) is applied to the shutter 102 so that the voltage-time average in two fields becomes 0V.
a, the transmission state in the transient response period 1201b and the holding period 1201c) is defined as the positive voltage application 1202b,
The transmission state in the field 1200b (the writing period 1201d, the transient response period 1201e, and the holding period 1201f) is referred to as a negative voltage application 1202d.

Also in this embodiment, the non-display state (1203a, 1203c) and the display state (120
There is an advantage that the duty ratio of 3b, 1203d) can be set freely.

(Embodiment 5) FIG. 13 is a view showing the structure of a display device according to a fifth embodiment. This embodiment is characterized in that a plurality of LED light sources 1301 are arranged in an array as the backlight 101, and can be turned off / on independently.

Although the LED light sources 1301 are arranged in a sidelight shape in FIG. 13, they may be two-dimensionally arranged directly below the liquid crystal shutter (not shown). In this case, the light-off / light-up operation may be controlled for each line.

As shown in FIG. 14, a plurality of cold cathode fluorescent tubes 1401 may be arranged as a direct type backlight in the direction of the divided area of the liquid crystal shutter, and similarly, may be independently turned off / on.

By adopting the above-described structure, as shown in FIG. 15, the light-off / light-on operation (1502a, 1502b) is performed in synchronization with the shutter operation (1501a, 1502b) of the liquid crystal shutter 102, so that the consumption is reduced. The power can be reduced. In this case, needless to say, a light source and a time which are not related to the transmissive display are selected as the light source to be turned off. Further, even when the response time of light emission and extinguishing is long as in the conventional fluorescent tube, the shutter operation of the liquid crystal shutter having a shorter response time becomes dominant, so that it can be used without any problem.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be implemented with various modifications.

For example, in the above-described embodiment, a flat display device is described as an example. However, in a projection display device such as a liquid crystal projector, a light source and a TFT-LC
A similar effect can be obtained by arranging a liquid crystal shutter between D and D. The form of the TFT-LCD may be a transmission type liquid crystal light valve or a reflection type liquid crystal light valve. It goes without saying that the desired effect can be obtained by providing a liquid crystal shutter for each panel and adopting the same form as in the above-described embodiment in either the three-panel type or the single-panel type.

In addition, the present invention can be variously modified and implemented without departing from the spirit thereof.

[0064]

According to the present invention, in a display device having a basic structure in which a shutter is disposed between a light valve and a backlight, the problem of moving image bleeding can be solved and the display quality can be improved. It becomes possible. Further, according to the present invention, it is possible to reduce the number of components of the display device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a structure of a display device according to a first example of the embodiment of the present invention.

FIG. 2 is a diagram illustrating an optical arrangement of a liquid crystal shutter according to the first embodiment.

FIG. 3 is a diagram illustrating a voltage-transmittance characteristic and a transmittance wavelength characteristic of the liquid crystal shutter according to the first embodiment.

FIG. 4 is a diagram showing a driving sequence in the first embodiment.

FIG. 5 is a diagram schematically showing a transition of a display state when a moving image is displayed in the first embodiment.

FIG. 6 is a diagram showing a structure of a display device according to a second example of the embodiment of the present invention.

FIG. 7 is a diagram showing a driving sequence in the second embodiment.

FIG. 8 is a diagram illustrating a voltage-transmittance characteristic of a liquid crystal shutter according to a second embodiment.

FIG. 9 is a diagram showing a driving sequence in a third example of the embodiment of the present invention.

FIG. 10 shows a voltage of a liquid crystal shutter according to a third embodiment.
The figure which showed about the transmittance characteristic and the response characteristic.

FIG. 11 is a diagram showing a voltage-transmittance characteristic and a response characteristic of a liquid crystal shutter applicable in the third example and the fourth example of the embodiment of the present invention.

FIG. 12 is a diagram showing a driving sequence in a fourth embodiment.

FIG. 13 is a view showing an example of the structure of a display device according to Example 5 of the embodiment of the present invention.

FIG. 14 is a view showing another example of the structure of the display device according to the fifth embodiment.

FIG. 15 is a diagram showing a driving sequence in the fifth embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 101 ... Back light 102 ... Liquid crystal shutter 103 ... TFT-LCD 104 ... Light source 105 ... Reflector 106 ... Light guide plate 107 ... Reflection plate 108 ... Condensing / diffusion sheet 109, 112, 115 ... Polarizing plate 110, 113 ... Liquid crystal layer 111, 114 ... substrate 401, 701a to 705a, 901a, 902a, 1
201a, 1201d... Write period 402, 701c to 705c, 901c, 902c, 1
201c, 1201f... Holding periods 403-406... TFT-LCD response waveforms 407, 408, 903a, 903b, 904a, 90
4b, 1202a to 1202d: liquid crystal shutter applied voltage waveforms 409, 410, 601a to 605a, 601b to 60
5b, 1203a to 1203d, 1501a, 1501
b: liquid crystal shutter transmissive / non-transmissive state 601 to 605 divided areas 701 to 705, 901, 902 TFT-LCD drive sequence 701b to 705b, 901b, 902b, 1201
b, 1201e: transient response period 903, 904: liquid crystal shutter drive sequence 1200a, 1200b: field period 1301: LED light source 1401: direct fluorescent tube type backlight 1502a, 1502b: light source on / off state

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Baba 1st Toshiba R & D Center, Komukai Toshiba, Saiwai-ku, Kawasaki City, Kanagawa Prefecture No. 1 town Toshiba Research & Development Center F-term (reference) 2H091 FA08X FA08Z FA41Z FA45Z GA01 GA13 HA07 HA10 HA12 LA30 2H093 NC34 NC42 ND39 ND60 NE01 NE06 NF05 NF13 NF17 NF20 5G435 AA04 BB12 BB09 EB17 FF17 DD12 GG11 GG23 GG24 GG26

Claims (5)

[Claims] 1. A light valve for displaying a color image based on a spatial additive color mixture by a plurality of pixels arranged in a two-dimensional matrix, a light for illuminating the light valve, and a light valve between the light valve and the light. And a shutter comprising a plurality of independently drivable areas configured to temporally switch between transmission and blocking of illumination light from the light. 2. The display device according to claim 1, wherein said light valve is constituted by a liquid crystal light valve, and said shutter is constituted by a liquid crystal shutter. 3. The light source includes a plurality of light sources corresponding to a plurality of independently drivable areas of the shutter, and each light source performs a light-on / off operation corresponding to a transmission and blocking operation in a corresponding area of the shutter. The display device according to claim 1, wherein the display device performs the operation. 4. The transmission and blocking operation in each of the independently drivable areas of the shutter corresponds to a screen updating operation in a corresponding area of the light valve. Display device. 5. A liquid crystal light valve configured to sandwich a liquid crystal layer between opposing substrates provided with a polarizing plate and displaying a color image based on spatial additive color mixture by a plurality of pixels arranged in a two-dimensional matrix; A liquid crystal layer is interposed between a light for illuminating the liquid crystal light valve and a counter substrate with a polarizing plate,
Provided between the liquid crystal light valve and the light,
A liquid crystal shutter configured to temporally switch between transmission and blocking of illumination light from the light, a polarizing plate on the liquid crystal shutter side of the liquid crystal light valve, and a liquid crystal shutter on the liquid crystal light valve side of the liquid crystal shutter. A display device characterized by sharing a polarizing plate.