JPH05307164A - Liquid crystal display device - Google Patents

Abstract

(57) [Summary] [Object] To provide a liquid crystal display device in which the brightness of a display image can be adjusted over a wide range and the brightness in the screen is uniform. [Structure] Backlight 3 and polarizing plates 101, 10 on both sides
The dimming panel 2 is placed on the display liquid crystal panel 1 having the transmissive liquid crystal panel 100 on which the dimming panel 2 is placed. The training panel 2 has the input terminals 209a to 209a provided at a plurality of locations.
From 09 g, a transmissive liquid crystal panel 200 configured to apply a driving AC signal and a polarizing plate 201 arranged on one side thereof
Have and.

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, and more particularly to a transmissive liquid crystal display device capable of uniformly adjusting the brightness of a displayed image over the entire screen.

[0002]

2. Description of the Related Art A conventional liquid crystal display device is shown in FIG. That is, this liquid crystal display device is
Liquid crystal panel 100 and polarizing plates 10 arranged on both sides thereof
1, 102 and a light source 3. Liquid crystal panel 100
Is a matrix display panel having a large number of pixels.
As the light source 3, a fluorescent tube is generally used.

In this liquid crystal display device, in the light emitted from the light source 3, only one of the two orthogonal components (P wave and S wave) passes through the polarizing plate 101. Polarizing plate 101
The light that has passed through enters the liquid crystal panel 100. The incident light has its polarization direction adjusted for each pixel of the liquid crystal panel 100 according to the signal applied to the pixel and enters the polarizing plate 102. The polarizing plate 102 allows only the light, of which the polarization absorption axis of the polarizing plate 102 is orthogonal to the polarization plane, out of the light emitted after passing through each pixel, to pass to the surface side where the image observer M is present. , The image is displayed. However, in the liquid crystal display device having such a configuration, changing the brightness of the entire display image is not basically considered.

On the other hand, a conventional liquid crystal display device for adjusting the brightness of a display image is disclosed in, for example, Japanese Patent Laid-Open No. 2-30.
As described in Japanese Patent No. 9316, there is known a liquid crystal display device that controls a backlight drive circuit in accordance with the light intensity of external light to change the display brightness.

[0005]

In the above-mentioned conventional liquid crystal display device, the brightness of the display image is adjusted by changing the brightness of the backlight which is the light source. The brightness of a fluorescent tube, which is the most commonly used light source, is generally adjusted by adjusting the current flowing through the fluorescent tube.

By the way, when dimming the backlight of the liquid crystal display device, for example, when the liquid crystal display device is used outdoors, it is brightened in the daytime so that it is easy to see even under the external light (sunlight). At night,
There may be a case where the brightness is required to be reduced to, for example, about several percent of the daytime brightness so as not to be dazzling.

However, when the current flowing through the fluorescent tube is reduced in order to reduce the brightness of the fluorescent tube, the fluorescent tube becomes unstable or does not illuminate when the current becomes small to some extent. .. Generally, the stable dimming limit of a fluorescent tube is 30% with respect to the maximum brightness (100%).
Since it is about 40%, there is a problem that the above-mentioned wide-range dimming is difficult to realize only by dimming the fluorescent tube.

Further, at the time of low brightness due to light control, the difference in brightness between the part near the fluorescent tube and the part distant from the fluorescent tube becomes noticeable, and the brightness of the displayed image becomes uneven.

An object of the present invention is to provide a liquid crystal display device capable of adjusting the brightness of a display image over a wide range and without causing unevenness on the screen.

[0010]

As a means for solving the above problems, according to one embodiment of the present invention, a display area having a substantially rectangular shape is provided, and polarizing plates are arranged on both sides of a panel. In a liquid crystal display device having an image display liquid crystal panel and a light source for illuminating the image display liquid crystal panel, a transmissive liquid crystal panel in which a polarizing plate is disposed on at least one of a light incident side and a light emitting side from the light source. And a dimming panel, and an AC signal generating circuit for applying an AC signal whose voltage amplitude is adjusted to the dimming panel, wherein the dimming panel is a thin film on one surface. The transparent plate having two transparent plates arranged such that the surfaces having the transparent electrodes face each other, and the liquid crystal material arranged between the thin film-shaped transparent electrodes. Is an AC signal to the transparent electrode. Has an input terminal for applying,
A liquid crystal display device is provided, wherein the input terminal is arranged at a position corresponding to at least two sides of a peripheral portion of a display area of the image display liquid crystal panel.

The two sides of the peripheral portion of the display area may be opposite two sides. Further, it may be two adjacent sides. Of course, there may be more sides, for example four sides. In this case, one or more input terminals can be provided on each side.

In addition, the transparent plate may further include an electrode that is in contact with the transparent electrode provided with the input terminal with a length corresponding to ½ or more of the length of the peripheral portion of the display area. This electrode can be formed in a strip shape, for example.

The dimming panel is arranged on the light incident side of the image display liquid crystal panel, and the polarizing plate may be arranged on the light incident side of the transmissive liquid crystal panel. Further, the light control panel may be arranged on the light emission side of the image display liquid crystal panel, and the polarizing plate may be arranged on the light emission side of the transmissive liquid crystal panel.

The alternating-current signal generating circuit can make the alternating-current cycle of the alternating-current signal applied to the dimming panel substantially the same as the liquid-crystal alternating cycle of the image display liquid crystal panel. Further, the AC signal generation circuit can make the AC cycle of the AC signal applied to the dimming panel shorter than the liquid crystal AC cycle of the image display liquid crystal panel.

According to another aspect of the present invention, there are provided an image display liquid crystal panel having a substantially rectangular display area and polarizing plates arranged on both sides of the panel, and an image display liquid crystal panel. A liquid crystal display device having a light source for illuminating, a dimming panel comprising a transmissive liquid crystal panel in which a polarizing plate is disposed on at least one of a light incident side and a light emitting side from the light source, and the dimming panel. And an AC signal generating circuit for applying an AC signal whose voltage amplitude is adjusted, wherein the dimming panel has a thin film transparent electrode on one surface, and a surface having the transparent electrode. It has two transparent plates arranged to face each other and a liquid crystal material arranged between the thin film-shaped transparent electrodes, and the transparent electrode has an input terminal for applying the AC signal. Has and input terminal is transparent The distance from any position of the pole, which corresponds to the display area of the image display liquid crystal panel, to any portion of the input terminal at the shortest position satisfies the condition that it is shorter than the length of the diagonal line of the display area. Provided is a liquid crystal display device characterized by being arranged.

[0016]

In a liquid crystal panel for image display using a polarizing plate, only light having a unidirectional polarization plane that has passed through the polarizing plate is used in the liquid crystal layer. On the other hand, the liquid crystal panel for dimming
The transmittance can be changed by rotating the polarization absorption axis of the polarizing plate arranged on at least only one side. Therefore, in the case where the maximum brightness is obtained by adjusting the amount of light incident on the image display liquid crystal panel or the amount of light emitted from the image display liquid crystal panel by the light control liquid crystal panel, Almost 100% of incident light or emitted light of the liquid crystal panel for image display can be used,
The amount of incident light or emitted light can be adjusted over a wide range.

Further, since the input terminals are arranged at positions corresponding to at least two sides of the peripheral portion of the display area of the image display liquid crystal panel, the applied voltage due to the impedance of the transparent electrode in the surface of the dimming panel is This prevents unevenness in the potential distribution drive signal amplitude due to the voltage drop.
As a result, it is possible to suppress the occurrence of uneven brightness.
Therefore, it is possible to adjust the light intensity of the display image over a wide range and to make the light adjustment amount in the plane of the display image uniform.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

The construction of the first embodiment of the liquid crystal display device of the present invention is shown in FIGS. FIG. 2 shows a specific configuration example of the image display liquid crystal panel 1 and the light control panel 2 in FIG.

1 and 5, an image display liquid crystal panel 1, a backlight 3 as a light source for illuminating the image display liquid crystal panel 1, a dimming panel 2, and the dimming panel 2 described above. An AC signal generation circuit 4 for applying an AC signal whose voltage amplitude is adjusted, an image processing circuit 5 that is a drive circuit of the image display liquid crystal panel 1, and a power supply 7.

The image display liquid crystal panel 1 has a rectangular display area 1a in which a plurality of pixels are arranged, and display data is sent from the image processing circuit 5 to be driven for display. The drive signal from the image processing circuit 5 is sent to the image display liquid crystal panel 1 through the wiring 6.

The backlight 3 is disposed on the back side of the image display liquid crystal panel 1, and a fluorescent tube 31 for irradiating the liquid crystal panel 1 and a drive inverter 32 for driving the fluorescent tube 31 to be turned on by the power of the power supply 7. Have and.

In the present embodiment, the light control panel 2 is arranged between the image display liquid crystal panel 1 and the backlight 3. The dimming panel 2 includes an AC signal generation circuit 4
It is driven by an AC signal sent via wirings 41 and 42.

The AC signal generating circuit 4 uses the vertical synchronizing signal Vsync output from the image processing circuit 5 as a trigger to generate an AC signal for driving the dimming panel 2 and a multivibrator 401 for amplifying the AC signal. Amplifier 402
Have and. From the amplifier 402, an AC signal DP and a signal C indicating the midpoint potential thereof are output.

In FIG. 1, the light emitted from the backlight 3 passes through the dimming panel 2 and the image display liquid crystal panel 1. As a result, the light of which the light amount is adjusted by the light control panel 2 is modulated for each pixel of the image display liquid crystal panel 1, and an image is displayed.

The configuration and operation of the image display liquid crystal panel 1 and the light control panel 2 will be described in detail with reference to FIG.

In FIG. 2, an image display liquid crystal panel 1 is shown.
Has a liquid crystal substrate 100 and polarizing plates 101 and 102 respectively arranged on both sides thereof. The liquid crystal panel 1 for image display in FIG. 1 is a liquid crystal substrate 100 having a large number of pixels arranged in a matrix, and the polarizing plates 101 and 102 are substantially integrated. The image display liquid crystal panel 1 is driven for each pixel according to a video signal applied from the image processing circuit 5, and displays an image. That is, it is a general liquid crystal display that has been put to practical use in the past. For the liquid crystal layer of the liquid crystal panel 1 for image display, for example, twisted nematic liquid crystal is used.

The light control panel 2 has a transmissive liquid crystal panel 200 and a polarizing plate 201. 202, 206
Is a glass substrate, 203 and 205 are transparent electrodes, 204 is a liquid crystal layer, 207 and 208 are sealing parts of the liquid crystal layer 204,
The transmissive liquid crystal panel 200 is formed by these.
As the liquid crystal layer 204, for example, twisted nematic liquid crystal is used. In FIG. 2, the polarizing plate 101,
Although the 102 and the liquid crystal substrate 100 are separated from each other, and the polarizing plate 201 and the transmissive liquid crystal panel 200 are separated from each other, the functions are the same even when they are arranged in close contact with each other. The dimming panel 2 shown in FIG. 1 is a transmissive liquid crystal panel 200 and a polarizing plate 201 that are substantially integrated.

The transparent electrodes 203 and 205 are provided on one surface of the glass substrates 202 and 206, respectively. Input terminals for applying the AC signal are connected to each other. As shown in FIG. 10, on the glass substrate 202, input terminals 209c and 209d are provided at positions corresponding to two opposite sides of the peripheral portion of the display area of the image display liquid crystal panel.
And 209h and 209g are arranged respectively. Further, on the glass substrate 206, the input terminals 209a, 209
b and 209e and 209f are arranged, respectively.
Input terminals 209c, 209d, 209h and 209g
Is connected to the transparent electrode 205, and the input terminals 209a, 2
09b, 209e and 209f are connected to the transparent electrode 206.

The glass substrates 202 and 206 are transparent electrodes 2
03 and 205 are arranged to face each other, and the liquid crystal layer 204 is provided inside thereof.

In FIG. 2, at point (a), the light emitted from the backlight 3 includes light in two polarization directions (S wave and P wave) orthogonal to each other, as shown in FIG. 3 (1). When the light emitted from the backlight 3 passes through the polarizing plate 201 and reaches the point (b), one of the two orthogonal components (which component passes is determined by the polarizing plate 201).
(Depending on the arrangement angle of), the amount of light is almost halved. FIG. 3B shows the case where only the S wave component of light passes. The intensity of the light at point (b)
It is represented by L in FIG. The light that has passed through the polarizing plate 201 is
Then, it passes through the transmissive liquid crystal panel 200.

The light passing through the liquid crystal panel 200 and reaching the point (c) has a light intensity L which does not change in principle as shown in FIG. Input terminals 209 at a plurality of locations on the liquid crystal panel 200
c, 209d, 209h and 209g, and the input terminal 2
The polarization direction is changed according to the amplitude of the alternating-current signal applied between 09a, 209b, 209e, and 209f. In the example of FIG. 3 (3), the polarization direction of light is 60
Shown is an example of a change. The transmissive liquid crystal panel 200
The light that has passed through passes through the polarizing plate 101 and reaches the point (d).

As an example of the arrangement of the polarizing plate 201 and the polarizing plate 101, when the polarization absorption axes are arranged in parallel, light of the same polarization direction is transmitted. That is, for example, the polarizing plate 20
Liquid crystal layer 2 so that the polarization direction of the light passing through 1 does not change
When the amplitude of the AC signal applied to 04 is set, in principle, all the light that has passed through the polarizing plate 201 is reflected by the polarizing plate 10.
Pass 1 as well. Therefore, there is no light loss due to passing through the polarizing plate 101. On the other hand, when the amplitude of the AC signal applied to the liquid crystal layer 204 is adjusted to change the polarization direction of the light passing through the polarizing plate 201 by 90 ° by the transmissive liquid crystal panel 200, the light passing through the polarizing plate 201 becomes Polarizing plate 101
Is almost completely shut off by. In the example of FIG. 3C, the polarization direction of light is rotated by 60 ° in the transmissive liquid crystal panel of FIG. 2, and in this case, almost half of the light incident on the polarizing plate 101 is generated by the polarizing plate 101. Pass through to reach point (d).

As described above, the amplitude of the AC signal applied to the transmissive liquid crystal panel 200 is adjusted to adjust the polarization direction of the light passing through the transmissive liquid crystal panel 200, thereby passing through the polarizing plate 101. The amount of light emitted can be adjusted over a wide range. As a result, the viewer M can be finally provided with the display of the optimum brightness.

Further, by applying an AC signal from the input terminals provided at two places on each of the two opposite sides,
It is possible to suppress variations in the AC signal amplitude within the surface of the transmissive liquid crystal panel 200 due to the wiring resistance of the transparent electrodes 203 and 205, and it is possible to prevent unevenness in the amount of light passing therethrough. If the input terminal is arranged only in one place and the area of the electrode is small, the amplitude of the AC signal differs between the part close to the input terminal and the part distant from the input terminal. It is conceivable that the amount of transmitted light of No. 2 becomes non-uniform in the plane and unevenness occurs in the brightness of the display image. That is, if the input terminal is arranged as in the present embodiment, the distance from the arbitrary position of the transparent electrode corresponding to the display area of the liquid crystal panel for image display to the portion of the input terminal at the shortest position, It is shorter than the diagonal length of the display area. Therefore, it is possible to reduce the decrease in the potential of the transparent electrode at the position farthest from the electrode. As a result, it is possible to suppress variations in AC signal amplitude within the surface of the transmissive liquid crystal panel 200 due to wiring resistance of the transparent electrodes 203 and 205. The dimming amount in the plane of the transmissive liquid crystal panel 200 can be made substantially uniform.

FIG. 4 shows an example of an AC signal applied to the dimming panel 2. Vsync in FIG. 4 is a signal for controlling the vertical scanning timing of the image display liquid crystal panel 1. Further, the liquid crystal alternating current of each pixel of the image display liquid crystal panel 1 is carried out at every vertical scanning period by Vsync. DP is an AC signal applied to the dimming panel 2, and its polarity is alternately inverted around the midpoint potential shown by the broken line.

Although FIG. 4 shows an example in which the polarity of the AC signal DP is inverted around a constant potential, instead of applying the AC signal to only one electrode, as shown in FIG. An alternating signal can be applied to both electrodes.
Even in this case, the same effect can be obtained. In this case, the amplitude of the AC signal DP ′ may be half that of the AC signal DP shown in FIG. 4, for example.

The AC signal DP shown in FIG. 4 is a signal whose polarity inversion cycle is equal to that of the vertical synchronizing signal Vsync. The AC signal DP having such a period is obtained by using the multivibrator 401 and the amplifier circuit 402 based on the vertical synchronizing signal Vsync as shown in the block diagram of FIG. 5, for example.

As described above, the liquid crystal of the image display liquid crystal panel 1 and the liquid crystal of the light control panel 2 are controlled by performing the light control using the AC signal DP having the same period as the liquid crystal alternating period of the image display liquid crystal panel 1. The alternating cycle can be adjusted. If the liquid crystal alternating cycle of the image display liquid crystal panel 1 and the liquid crystal alternating cycle of the dimming panel 2 are different as shown in FIG. 6, for example, flickering of the displayed image, that is, flicker may occur. Conceivable.

It is generally known that when the liquid crystal panel is driven by an AC signal, flicker having the same period as the frequency of the AC signal occurs. However, the image display liquid crystal panel 1 is generally subjected to alternating current at a frequency of 30 Hz (in the case of the NTSC system), and since the period is relatively short, when viewing the image display panel 1 alone. Has
Almost no flicker is felt by human eyes. On the other hand, when the image display panel 1 and the dimming panel 2 are stacked and viewed, if the alternating periods of the image display liquid crystal panel 1 and the dimming panel 2 are different, flicker is visible. It is possible. That is, for example, the alternating frequency of the image display liquid crystal panel 1 is f1, the alternating frequency of the dimming panel 2 is f2, the emitted light intensity of the backlight 3 is Φ,
If the intensity of light that has passed through the two liquid crystal panels is Φ1, then it is conceivable that the light that passes through the two liquid crystal panels will have two components represented by the following equation.

[0041]

[Equation 1]

That is, it is considered that a sum component and a difference component of the alternating frequencies of the two liquid crystal panels occur. At this time, the sum component becomes higher than the original frequency, so it cannot be seen by the human eye. However, since the difference component is lower than the original frequency, it is possible that flicker is visible. For example, the AC frequency of the image display liquid crystal panel 1 is 30 Hz, and the AC frequency of the dimming panel 2 is 40H.
If z, it is conceivable that the difference component of 10 Hz is visible as flicker.

On the other hand, according to the present invention, the liquid crystal alternating cycle of the image display liquid crystal panel 1 and the dimming panel 2 can be made the same, so that no visible flicker occurs.

FIG. 7 shows a waveform example when an AC signal DP different from that shown in FIG. 4 is used. The AC signal DP shown in FIG. 7 is
The signal has a shorter cycle than Vsync. For example, the cycle of Vsync is about 16.7 ms (frequency 60 Hz, but in case of NTSC system), whereas the AC signal DP is 1 ms (frequency 1 KH).
z) or a signal with a shorter period than that. In this way, the dimming panel 2 is generated by using the AC signal DP having a cycle shorter than the AC conversion cycle of the image display liquid crystal panel 1.
By driving, the liquid crystal alternating current cycle of the light control panel 2 can be shortened and the flicker can be made invisible.

Next, a second embodiment of the present invention will be described. FIG. 11 shows the outline of the configuration of the second embodiment of the liquid crystal display device of the present invention. The embodiment shown in FIG. 11 is an example in which light control is automatically performed according to the external brightness.

That is, the present embodiment includes an image display liquid crystal panel 1, an image processing circuit 5, a light control panel 2, and an AC signal generation circuit 4. These components are almost the same as those in the first embodiment. However, there is a difference in that a variable amplifier whose amplification factor can be changed based on an external signal is used as the amplifier 402 of the AC signal generation circuit 4. In addition, in this embodiment, the light receiving element 8 for detecting external light is used.
And an external light intensity detection circuit 9 that detects the external light intensity from the detection signal of the light receiving element 8 and outputs a signal indicating the external brightness.
And an amplifier 402 based on a signal indicating the external brightness.
And an amplification factor control circuit 10 for controlling the amplification factor of.

In such a configuration, the brightness of the environment in which the liquid crystal display device is placed is detected by the intensity of the light incident on the light receiving element 8, and the output voltage of the external light intensity detection circuit 9 is changed. The amplification factor control circuit 10 controls the amplification factor of the amplifier 402 according to the change of the output voltage, that is, the signal indicating the external brightness. As a result, the voltage amplitude of the AC signal applied to the dimming panel 2 changes, and its transmittance changes.

Therefore, according to this embodiment, the dimming amount of the dimming panel 2 is automatically determined according to the brightness of the outside, that is, the surrounding brightness. Therefore, it is particularly suitable for applications such as a vehicle-mounted display device that does not impose a heavy operational burden on the user.

Next, another embodiment of the light control panel used in the present invention will be described.

FIG. 12 shows an example of the structure of the light control panel 2. 209a to 209h are input terminals for AC signals, 210
Reference characters a and 210b are electrodes having a large area formed of, for example, a metal having a low impedance such as Al. Note that FIG.
When viewed from the direction shown in FIG. 3, the AC signal input terminals 209a, 209b, 209e and 209 of the glass plate 206 are not shown because they are behind the glass plate 206.
An electrode made of a low-impedance metal similar to 210a and 210b is also disposed on the surface on which f is disposed.

As shown in FIG. 12, an AC signal is applied to the dimming panel 2 by using an electrode formed of a low-impedance metal and having a large area, so that only the AC signal input terminals 209a to 209h are used. As compared with the case where an AC signal is applied from a portion having a small area, it is possible to further reduce the unevenness of the amplitude of the AC signal applied to the transparent electrode of the dimming panel 2, and it is possible to perform more uniform dimming. ..

In this example, of the glass substrate 202,
Although the strip-shaped electrodes 210a and 210b are provided along the entire side where the input terminal is provided, the electrodes 210a and 210b do not necessarily have to be provided along the entire side. For example, it can be provided so as to be in contact with the transparent electrode provided with it at a length corresponding to ½ or more of the length of the peripheral portion of the display region.

Further, in the present invention, it is possible to use various forms of light control panels as shown in FIGS. In each of these examples, the glass plates 202, 20
Input terminal 209g, 209
d and input terminals 209a and 209e are provided. In the example of FIG. 13, these terminals are provided at the central portions of the two opposite sides. In the example of FIG. 14, these terminals are
The two opposing sides are provided in a positional relationship parallel to the diagonal line. In the example of FIG. 15, the glass plate 20 having a substantially square shape is used.
2, 206 is an example in which two opposing sides are provided in a positional relationship parallel to the diagonal line.

In the example of FIG. 16, these terminals are examples in which substantially square glass plates 202 and 206 are used, and the terminals are provided on two adjacent sides in a positional relationship parallel to the diagonal line. .. Further, in this example, the electrodes 212 and 213 having an L-shape and having a low impedance are provided on the two adjacent sides where the terminals are provided, as in the example shown in FIG.

In each of the above embodiments, the dimming panel 2 is arranged on the light incident side of the image display liquid crystal panel, and the polarizing plate 201 is arranged on the light incident side of the transmissive liquid crystal panel 200. Shows. However, the present invention is not limited to this. For example, the dimming panel 2 may be arranged on the light emission side of the image display liquid crystal panel and the polarizing plate 201 may be arranged on the light emission side of the transmissive liquid crystal panel 200.

Although the display area of the display liquid crystal panel is rectangular in the above embodiment, it is needless to say that the present invention can be applied even if the display area is not strictly rectangular. For example, it may be a square. Further, the shape may be such that each corner of the rectangle has a curvature.

[0057]

As described above, according to the present invention, it is possible to obtain the liquid crystal display device in which the brightness of the display image can be adjusted over a wide range and the brightness in the screen is uniform.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a first embodiment of the present invention.

FIG. 2 is a side view showing a specific configuration example of a light control panel used in the first embodiment.

FIG. 3 is an explanatory diagram showing the amount of light and the polarization direction at points (a), (b), (c), and (d) in FIG.

FIG. 4 is a waveform chart showing an AC signal waveform applied to the light control panel of the first embodiment.

FIG. 5 is a block diagram showing a specific configuration example of an AC signal generation circuit in the first embodiment.

FIG. 6 is a waveform chart showing AC timing of the liquid crystal display device in the first embodiment.

FIG. 7 is a waveform diagram showing a waveform different from that of FIG. 4 of an AC signal waveform applied to the dimming panel of the first embodiment.

FIG. 8 is a side view showing a specific configuration example of a conventional liquid crystal display device.

FIG. 9 is a waveform diagram showing an AC signal waveform applied to the light control panel of the first embodiment.

FIG. 10 is a diagram showing an arrangement example of input terminals in the light control panel used in the first embodiment, where (A) is a front view, (B) is a side view, and (C) is a plan view.

FIG. 11 is a block diagram showing a configuration of a second embodiment of the liquid crystal display device of the present invention.

FIG. 12 is an explanatory diagram showing another configuration of the input terminal arrangement in the light control panel used in the present invention.

FIG. 13 is an explanatory diagram showing another configuration of the input terminal arrangement in the light control panel used in the present invention.

FIG. 14 is an explanatory diagram showing another configuration of the input terminal arrangement in the light control panel used in the present invention.

FIG. 15 is an explanatory diagram showing another configuration of the input terminal arrangement in the light control panel used in the present invention.

FIG. 16 is an explanatory diagram showing another configuration of the input terminal arrangement in the light control panel used in the present invention.

[Explanation of symbols]

1 ... Liquid crystal panel for image display 2 ... Panel for dimming 3
... Backlight 4 ... AC signal generation circuit 5 ... Image processing circuit 6,4
1, 42 ... Wiring 7 ... Power supply 100 ... Liquid crystal substrate 101, 102, 20
1 ... Polarizing plate 202, 206 ... Glass substrate 203, 205 ... Transparent electrode 204 ... Liquid crystal layer 207, 208 ... Liquid crystal sealing part

Claims (9)

[Claims] 1. A liquid crystal display having an image display liquid crystal panel, which has a substantially rectangular display region, and polarizing plates are disposed on both sides of the panel, and a light source for illuminating the image display liquid crystal panel. In the device, a dimming panel including a transmissive liquid crystal panel in which a polarizing plate is disposed on at least one of a light incident side and a light emitting side from a light source, and an AC signal whose voltage amplitude is adjusted are applied to the dimming panel. An AC signal generating circuit for applying the voltage, and the dimming panel has thin-film transparent electrodes on one surface thereof, and two light-transmitting panels are arranged so that the surfaces having the transparent electrodes face each other. A transparent plate and a liquid crystal material disposed between the thin film transparent electrodes, the transparent plate has an input terminal for applying an AC signal to the transparent electrode, the input terminal, Of the liquid crystal panel for image display The liquid crystal display apparatus characterized by being arranged to position corresponding to at least two sides of the periphery of the display region. 2. The liquid crystal display device according to claim 1, wherein two edges of a peripheral portion of the display area are two edges facing each other. 3. The liquid crystal display device according to claim 1, wherein two edges of the peripheral portion of the display area are two adjacent edges. 4. The liquid crystal display according to claim 1, further comprising an electrode that is in contact with a transparent electrode provided with an input terminal with a length corresponding to ½ or more of a length of a peripheral portion of the display area. apparatus. 5. The light control panel according to claim 1, wherein the light control panel is disposed on the light incident side of the image display liquid crystal panel,
Moreover, a liquid crystal display device in which a polarizing plate is disposed on the light incident side of a transmissive liquid crystal panel. 6. The light control panel according to claim 1, wherein the light control panel is disposed on a light emission side of the image display liquid crystal panel,
Moreover, a liquid crystal display device in which a polarizing plate is arranged on the light emission side of a transmissive liquid crystal panel. 7. The alternating current signal generating circuit according to claim 1,
A liquid crystal display device in which an alternating current cycle of an alternating current signal applied to a light control panel is substantially equal to a liquid crystal alternating current cycle of an image display liquid crystal panel. 8. The alternating current signal generating circuit according to claim 1,
A liquid crystal display device for making an AC conversion cycle of an AC signal applied to a light control panel shorter than a liquid crystal AC conversion cycle of an image display liquid crystal panel. 9. A liquid crystal display having a liquid crystal panel for image display, which has a substantially rectangular display region, and polarizing plates are arranged on both sides of the panel, and a light source for illuminating the liquid crystal panel for image display. In the device, a dimming panel including a transmissive liquid crystal panel in which a polarizing plate is disposed on at least one of a light incident side and a light emitting side from a light source, and an AC signal whose voltage amplitude is adjusted are applied to the dimming panel. An AC signal generating circuit for applying the voltage, and the dimming panel has thin-film transparent electrodes on one surface thereof, and two light-transmitting panels are arranged so that the surfaces having the transparent electrodes face each other. A transparent plate and a liquid crystal material disposed between the thin film transparent electrodes, the transparent electrode has an input terminal for applying the AC signal, the input terminal of the transparent electrode , The liquid crystal panel for image display Is arranged such that the distance from an arbitrary position corresponding to the display area to the arbitrary portion of the input terminal at the shortest position is shorter than the length of the diagonal line of the display area. Liquid crystal display device.