JP2002196308A - Liquid crystal display - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Although using a simple matrix liquid crystal display element, almost no difference in luminance occurs on the screen of the liquid crystal display element due to external factors, and the quality of the screen is almost uniform. Provided is a liquid crystal display device capable of obtaining a display. A simple matrix liquid crystal display element (1) supplies a selection signal and a data signal to a plurality of scanning electrodes (4) and scanning electrodes (5) of the liquid crystal display element (1), and one field for sequentially selecting all the scanning electrodes (4). The selection period in which the selection signal is supplied to each scanning electrode 4 within the allocation period allocated to each of the scanning electrodes 4 is determined by an external factor that causes a luminance difference on the screen of the liquid crystal display element 1, for example, the illumination unit. Light source 1 of liquid crystal display element 1 due to heat generated by light source 13
It is driven by a driving unit 17 that controls so as to compensate for a luminance difference of a screen due to a temperature rise in a region close to 3.

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 using a simple matrix liquid crystal display device.

[0002]

2. Description of the Related Art There are two types of liquid crystal display devices: a simple matrix type and an active matrix type. The simple matrix type is advantageous in terms of price.

In the simple matrix liquid crystal display device, a plurality of scanning electrodes are provided on one inner surface of a pair of front and rear substrates facing each other with a liquid crystal layer interposed therebetween, and a plurality of scanning electrodes are provided on the inner surface of the other substrate along a column direction. The liquid crystal display device using the simple matrix liquid crystal display device includes the simple matrix liquid crystal display device and driving means for driving the liquid crystal display device in a time-division manner. .

The driving means supplies the selection signal to each of the scanning electrodes in a selection period assigned to each of the scanning electrodes in one field for sequentially selecting all of the scanning electrodes of the liquid crystal display element. In synchronization with the selection period of each scanning electrode, a data signal of a potential corresponding to the display data is supplied to each signal electrode, and a liquid crystal layer is provided between the electrodes where the scanning electrode and the signal electrode of the liquid crystal display element intersect. Are driven by applying a voltage for operating the. .

The liquid crystal display element is of a TN (twisted nematic) type in which liquid crystal molecules in a liquid crystal layer are twist-oriented at a twist angle of about 90 ° and a polarizing plate is disposed on the outer surfaces of a pair of substrates. Although widely used, the simple matrix liquid crystal display element operates with the effective voltage between the electrodes, and therefore, when it is driven in a time-division manner at a high duty, the operation margin is reduced and the display contrast is reduced.

Therefore, a large-screen simple matrix liquid crystal display device having a large number of pixels requires liquid crystal molecules of 180 ° to 27 °.
A STN (super twisted nematic) type liquid crystal display element in which a twist is oriented at a twist angle of 0 ° (usually 240 ° to 260 °) is used.

The STN type liquid crystal display element has a large twist angle of the liquid crystal molecules, so that a change in light transmittance with respect to a voltage applied between the electrodes is large. Therefore, a simple matrix for operating the liquid crystal molecules by an effective voltage is used. Even if it is a type, it can be driven in a time-division manner at a high duty without lowering the contrast.

In addition, the liquid crystal display device has a reflection means on the rear side of the liquid crystal display element, and a reflection type in which display is performed by using external light incident from the front side, which is a display observation side, and a liquid crystal display element. Illuminating means is provided behind the illuminating means, a transmissive type that displays by using the illuminating light emitted by the illuminating means, and a function of reflecting incident light from the front side and a illuminating light on the rear side of the liquid crystal display element. An illuminating unit having a function of emitting light toward the liquid crystal display element is arranged, and in an environment where external light of sufficient brightness is obtained, display is performed using external light, and external light of sufficient brightness is obtained. Under the environment, there are reflection / transmission type displays that use illumination light, and the reflection type liquid crystal display device performs only reflection display using external light;
A reflection unit is provided on the rear side of the liquid crystal display element, and the front side of the liquid crystal display element has a function of transmitting incident light from the front side and the rear side and a function of emitting illumination light toward the liquid crystal display element. It should be equipped with lighting means and display using external light in an environment where external light of sufficient brightness can be obtained, and display using illumination light in an environment where external light of sufficient brightness can be obtained. There is.

The illumination means of the transmission type liquid crystal display device includes:
A light source disposed on the side of the rear side of the liquid crystal display element, and disposed opposite to the rear surface of the liquid crystal display element, taking in the light emitted from the light source from an end face and facing the liquid crystal display element from the front side. The light emitting means of the reflection / transmission type liquid crystal display device is provided with a semi-transmissive reflection plate in front of the light guide plate, or a reflection plate on the rear surface of the light guide plate. It has a configuration provided.

The illuminating means of the reflection type liquid crystal display device using both the external light and the illuminating light includes a light source disposed on the front side of the liquid crystal display element and a front face of the liquid crystal display element. And a transparent light guide plate that receives light emitted from the light source from an end face and emits the light from the rear face toward the liquid crystal display element.

Further, some liquid crystal display devices are provided with a liquid crystal display element which can be tilted in the front-rear direction, such as a liquid crystal display device mounted on an opening / closing lid of a notebook personal computer (personal computer). is there.

[0012]

However, the above transmission type,
The reflection / transmission type liquid crystal display devices using both the external light and the illumination light are used in the reflection type liquid crystal display devices, because the heat generated by the light source of the illumination means raises the temperature of a region near the light source of the liquid crystal display element.
The temperature rise in that region becomes an external factor, and a difference occurs between the screen luminance of the region near the light source of the liquid crystal display element and the screen luminance of the other regions.

That is, when the temperature of a region near the light source of the liquid crystal display element rises due to the heat generated by the light source of the illuminating means, the response characteristic of the liquid crystal in the temperature rising region (response characteristic to voltage).
Changes, a difference occurs in the screen luminance between an area close to the light source and another area.

Further, in the case of a liquid crystal display device in which the liquid crystal display element is provided so as to be tiltable in the front-back direction, the tilt angle of the liquid crystal display element is adjusted according to the preference of the display observer. The tilt angle of the liquid crystal display element in the front-rear direction is designed so that the optimal viewing angle for observing the display with the brightest and good contrast is in the front direction (direction near the normal of the screen). The difference between the viewing angles of the respective areas of the screen, which varies according to, becomes an external factor, and the screen brightness of the area observed at a viewing angle where the difference with respect to the optimum viewing angle is small, and the area observed at a viewing angle where the difference with respect to the optimum viewing angle is large Is different from the screen brightness.

The temperature rise near the light source of the liquid crystal display element due to the heat generated by the light source of the illuminating means, and the brightness difference of the screen caused by the difference in the viewing angle as an external factor are caused by the simple operation in which the liquid crystal molecules operate by the effective voltage between the electrodes. ST is conspicuous in a matrix liquid crystal display element, especially when the twist angle of liquid crystal molecules is large.
The N-type simple matrix liquid crystal display element has a large screen luminance difference due to the external factors.

According to the present invention, although a simple matrix liquid crystal display element is used, a difference in luminance on the screen of the liquid crystal display element due to external factors is almost eliminated, and a display of high quality with substantially uniform screen luminance is achieved. It is an object to provide a liquid crystal display device that can be obtained.

[0017]

According to the liquid crystal display device of the present invention, a plurality of scanning electrodes are provided along the row direction on one inner surface of a pair of front and rear substrates facing each other with a liquid crystal layer interposed therebetween, and the inner surface of the other substrate is provided. A simple matrix liquid crystal display element provided with a plurality of signal electrodes along the column direction, and a selection signal and a data signal are respectively supplied to the plurality of scanning electrodes and signal electrodes of the liquid crystal display element, and all the scanning electrodes are sequentially turned on. The selection period in which the selection signal is supplied to each scan electrode within the allocation period allocated to each scan electrode in one field to be selected is allocated to one scan electrode in one field for scanning all scan electrodes. A selection period during which a selection signal is supplied to each scanning electrode within the allocation period is determined by an external factor that causes a luminance difference on the screen of the liquid crystal display element. It is characterized in that a drive means for controlling to compensate for the luminance difference.

In this liquid crystal display device, a simple matrix liquid crystal display element is supplied with a selection signal and a data signal to a plurality of scanning electrodes and signal electrodes, respectively, and each scanning electrode in one field for sequentially selecting all scanning electrodes. Select the selection period for supplying the selection signal to each scan electrode within the allotment period assigned to each scan electrode in the allotment period assigned to one scan electrode in one field for scanning all the scan electrodes. Since the selection period for supplying the signal is driven by the driving unit that controls so as to compensate for the luminance difference of the screen due to an external factor, the simple matrix liquid crystal display element is used. Accordingly, it is possible to almost eliminate the occurrence of a luminance difference on the screen of the liquid crystal display element, and to obtain a high quality display with substantially uniform screen luminance.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, a liquid crystal display device according to the present invention comprises a simple matrix liquid crystal display element which supplies a selection signal and a data signal to a plurality of scanning electrodes and signal electrodes, respectively. A selection period for supplying the selection signal to each scanning electrode within an allocation period allocated to each scanning electrode in one field for sequentially selecting
A selection period for supplying a selection signal to each scanning electrode within an allocation period allocated to one scanning electrode in one field for scanning all the scanning electrodes is set to an external period that causes a luminance difference on the screen of the liquid crystal display element. According to the factor, by driving by a driving unit that controls so as to compensate for the luminance difference of the screen due to the external factor, it is possible to almost eliminate the occurrence of the luminance difference on the screen of the liquid crystal display element due to the external factor,
It is intended to obtain a high quality display with substantially uniform screen luminance.

In the liquid crystal display device according to the present invention, the liquid crystal display device is disposed on one of the front and rear sides thereof so as to extend along a direction perpendicular to the length direction of the scanning electrode of the liquid crystal display device. And a light guide plate disposed opposite to the front or rear surface of the liquid crystal display element and taking light emitted from the light source from an end face and emitting the light from the front or rear surface toward the liquid crystal display element. When the means is provided, an external factor that causes a luminance difference on the screen of the liquid crystal display element is a temperature rise in a region near the light source of the liquid crystal display element due to heat generated by the light source of the lighting means, and The driving means may be one which controls the selection period of the scanning electrodes in the region of the liquid crystal display element near the light source to be shorter than the selection period of the scanning electrodes in the other regions.

In this case, it is preferable that the driving means be configured to control the scanning electrode on the higher temperature side to shorten the selection period in accordance with the temperature gradient in the temperature rising region of the liquid crystal display element.

Also, in the liquid crystal display device of the present invention,
When the liquid crystal display element is provided so as to be tiltable in the front-rear direction around the length direction of the scanning electrode, an external factor that causes a luminance difference on the screen of the liquid crystal display element is the scanning electrode length of the screen. Difference between the viewing angles of the respective regions along the direction perpendicular to the vertical direction. It suffices if the selection period of the scanning electrode in the region observed at the viewing angle where the difference is large is controlled to be longer than the selection period of the scanning electrode in the region observed at the viewing angle where the difference from the optimal viewing angle is small.

In this case, the driving means sets the selection period of each scanning electrode of the liquid crystal display element from a region where the difference with respect to the optimum viewing angle is observed at a large viewing angle to a region where the difference with respect to the optimum viewing angle is observed at a small viewing angle. It is desirable to adopt a configuration in which control is performed so as to be sequentially shortened.

When the external factor causing a luminance difference on the screen of the liquid crystal display element is a change in the viewing angle due to the tilt angle of the liquid crystal display element in the front-rear direction, the driving means sets the tilt angle of the liquid crystal display element. An angle sensor for measuring the angle, and a configuration for controlling the selection time of each scanning electrode of the liquid crystal display element according to the tilt angle measured by the angle sensor, or including a brightness adjustment unit that is manually operated, The configuration may be such that the selection time of each of the scanning electrodes is controlled in accordance with the operation of the luminance adjustment unit.

[0025]

FIG. 1 shows a first embodiment of the present invention. FIG. 1 is a schematic structural view of a liquid crystal display device, and FIG. 2 is a side view of the liquid crystal display device.

The liquid crystal display device of this embodiment is of a transmissive type, and as shown in FIGS. 1 and 2, a simple matrix liquid crystal display device 1 and an illuminating means 12 provided behind the liquid crystal display device 1. And a driving unit 17 for driving the liquid crystal display element 1 in a time-division manner.

FIG. 3 is a cross-sectional view of a part of the simple matrix liquid crystal display device 1. The simple matrix liquid crystal display device 1 has one of a pair of front and rear transparent substrates 2 and 3 opposed to each other with a liquid crystal layer 9 interposed therebetween. Substrate, for example, on the inner surface of the front substrate 2, which is the display observation side, in the row direction (the horizontal direction of the screen).
Are provided, and a plurality of transparent signal electrodes 5 are provided on the inner surface of the other rear substrate 3 along the column direction (vertical direction of the screen).

The liquid crystal display element 1 is for displaying a multi-color image such as a full-color image and the like.
And the signal electrode 5 correspond to a plurality of pixel portions facing each other, and a color filter 6 of three colors of red, green and blue is provided.
R, 6G and 6B are provided. The color filters 6R, 6G, 6B are formed on the inner surface of the front substrate 2, and the scanning electrodes 4 are formed thereon.

The liquid crystal display element 1 is of the STN type, and the liquid crystal molecules of the liquid crystal layer 9 are formed on the innermost surfaces of the pair of substrates 2 and 3 by 180 ° to 270 ° (preferably 240 ° to 260 °). ), Alignment films 7 and 8 for twist alignment at a twist angle are provided, and polarizing plates 10 and 11 are arranged on the outer surfaces of the pair of substrates 2 and 3 with their transmission axes directed in a predetermined direction. I have.

The pair of substrates 2 and 3 are joined at their peripheral edges via a frame-shaped sealing material (not shown), and a region surrounded by the sealing material between the substrates 2 and 3 is provided. A liquid crystal layer 9 is provided. The polarizing plates 10 and 11 are attached to the outer surfaces of the pair of substrates 2 and 3, respectively.

As shown in FIG. 2, the illuminating means 12 is arranged on the rear side of the liquid crystal display element 1 in a direction orthogonal to the length direction of the scanning electrode 4 of the liquid crystal display element 1. A light source 13 arranged alongside the transparent liquid crystal is disposed so as to face the rear surface of the liquid crystal display element 1, receives light emitted from the light source 13 from an end face, and emits the light toward the liquid crystal display element 1 from the front surface. The light source 13 includes a straight tubular cold-cathode tube 14 and a reflector 15 that reflects light emitted from the cold-cathode tube 14 toward an end face of the light guide plate 16. Have been.

The illumination means 12 used in this embodiment
The light source 13 is provided on one side of one of two edges (upper and lower edges in FIG. 1) orthogonal to the length direction of the scanning electrode 4 of the liquid crystal display element 1. The light guide plate 16 takes in the light emitted from the light source 13 from one end face facing the light source 13, guides the light, and emits the light from the entire front surface to the liquid crystal display element 1.

On the other hand, as shown in FIG. 1, the driving means 17 comprises a scanning side driving circuit 18 for supplying a selection signal to each of the plurality of scanning electrodes 4 of the liquid crystal display element 1, and a driving circuit 17 for the liquid crystal display element 1. It comprises a signal-side drive circuit 19 for supplying a data signal to each of the plurality of signal electrodes 5, and a control circuit 20 for controlling the scan-side drive circuit 18 and the signal-side drive circuit 19.

The driving means 17 is provided for driving the liquid crystal display element 1.
Supply a selection signal and a data signal to a plurality of scan electrodes 4 and signal electrodes 5, respectively, and select all scan electrodes 4 sequentially. Each scan electrode in an assignment period assigned to each scan electrode 4 in one field. The control section controls the selection period in which the selection signal is supplied to the liquid crystal display element so as to compensate for the luminance difference of the screen due to the external factor in accordance with an external factor causing a luminance difference on the screen of the liquid crystal display element. That is,
The control circuit 20 supplies a clock pulse to the scanning side driving circuit 18 and the signal side driving circuit 19,
The display data corresponding to the image signal supplied from the outside is supplied to the signal side drive circuit 19.

The signal side drive circuit 19 counts the number of clock pulses for the assigned period assigned to each scan electrode 4 and synchronizes with the assigned period of each scan electrode 4 corresponding to the count of the number of clock pulses. Then, a data signal having a potential corresponding to the display data is supplied to each signal electrode 5 of the liquid crystal display element 1.

Further, the scanning side driving circuit 18 measures the allocation period by the number of clock pulses,
According to an external factor that causes a luminance difference on the screen of the liquid crystal display element 1, the selection period of each scanning electrode 4 is set to a predetermined time so as to compensate for the luminance difference of the screen due to the external factor, During the allocation period, a selection period preset for each scanning electrode 4 is measured by the number of clock pulses, and a selection signal is supplied to each scanning electrode 4 only during the selection period. In this liquid crystal display device, the area of the liquid crystal display element 1 near the light source 13 is heated by the heat generated by the light source 13 of the illumination means 12. This is an external factor that causes a difference between the screen luminance of the near area and the screen luminance of another area.

The temperature rise in the area of the liquid crystal display element 1 close to the light source 13 is determined by the heat generation temperature of the light source 13 and the distance between the liquid crystal display element 1 and the light source 13. The temperature of the display element 1 rises with a constant temperature gradient in which the temperature rises as it approaches the light source 13.

Therefore, in this embodiment, the light source 13
The selection period of a predetermined number of the scanning electrodes 4 in a region close to the scanning electrodes 4 is set shorter than the selection period of the other scanning electrodes 4, and the number of clock pulses corresponding to the selection periods of the scanning electrodes 4 is determined by the scanning side driving circuit 18. Is stored in advance.

In this embodiment, each scan in a temperature-raising region (a region where the screen luminance rises to such an extent that the screen luminance looks different from the screen luminance of other regions) due to the heat generated by the light source 13 of the liquid crystal display element 1 is described. The selection period of the electrodes 4 is set shorter than the allocation period, and the selection periods of the scan electrodes 4 in other areas are set to be the same as the allocation period.

Further, as described above, the temperature of the liquid crystal display element 1 rises with a constant temperature gradient in which the temperature rises as it approaches the light source 13. The selection period of each scanning electrode 4 is
In accordance with the temperature gradient in the heating region, the scanning electrode 4 on the high temperature side
It is set as short as possible.

FIG. 4 shows a case where the number of scanning electrodes in a temperature-raising region (a region where the screen luminance rises to such an extent that it looks different from the screen luminance of other regions) due to the heat generated by the light source 13 of the liquid crystal display element 1 is eight. FIG. 7 is a waveform diagram of a selection signal supplied to each scanning electrode 4 in the case of a book. Here, selection signals C1 to C3 supplied to first to third scanning electrodes 4 counted from the side close to the light source 13 are shown. And the eighth to tenth scanning electrodes 4
5 shows the waveforms of the selection signals C8 to C10 supplied to.

As shown in FIG. 4, when the number of scanning electrodes in the heating region of the liquid crystal display element 1 is eight, the light source 13
Are supplied to the ninth and subsequent scanning electrodes 4 counted from the side closer to
.., T10... Are signals having the same pulse width as the assigned period T assigned to all the scan electrodes 4, and the first to eighth scans counted from the scan electrodes in the heating region, that is, the side closer to the light source 13. The selection signals C1 to C8 to be supplied to the electrodes 4 have the pulse widths in the selection periods T1 to T8, which have the pulse widths in the allocation period T.
And the selection period T1 to T8 is shorter than the light source 1
The scanning signal 4 on the high temperature side closer to 3 has a shorter pulse width.

The selection signals C1 to C8 to be supplied to the first to eighth scanning electrodes 4 shown in FIG. The selection signal C1 to C8 supplied to the first to eighth scan electrodes 4 is a signal having a waveform which becomes a non-selection potential before the end of the period T.
Is shorter than the assignment period T, for example, the potential becomes the selection potential after the assignment period T, and
May be a signal having a waveform that becomes a non-selection potential at the same time when the operation is completed.

The liquid crystal display device comprises the liquid crystal display element 1
The selection period of each scanning electrode 4 within the allocation period in one field equally allocated to all of the scanning electrodes is changed according to an external factor that causes a luminance difference on the screen of the liquid crystal display element 1. Since it is driven by the driving means 17 for controlling so as to compensate for the luminance difference of the screen due to external factors, the light source 13 of the illumination means 12 emits light although the STN type simple matrix liquid crystal display element is used. A difference in luminance on the screen of the liquid crystal display element 1 caused by the temperature rise of the liquid crystal display element 1 near the light source 13 due to heat is almost eliminated, and a high quality display with almost uniform screen luminance can be obtained.

That is, when the temperature of the area near the light source 13 of the liquid crystal display element 1 rises due to the heat generated by the light source 13 of the illuminating means 12, the viscosity of the liquid crystal in the temperature rising area decreases and the response characteristic to voltage changes. Therefore, all the scanning electrodes 4
If the selection period is the same, for example, in the case of a liquid crystal display element in a normally black mode, the screen brightness in the temperature rising area near the light source 13 is higher than the screen brightness in other areas,
In the case of a normally white mode liquid crystal display device, the screen brightness in the temperature rising area is lower than the screen brightness in other areas.

However, in this embodiment, the selection period of the scanning electrode 4 in the temperature rising region near the light source 13 of the liquid crystal display element 1 is controlled to be shorter than the selection period of the scanning electrode 4 in the other region. The energy of the effective voltage of the pixel portion in the temperature rising region can be smaller than the energy of the effective voltage of the pixel portion in the other region.

Therefore, in the case of a normally black mode liquid crystal display element, the increase in the screen brightness in the temperature rising region is offset by reducing the energy of the effective voltage, and in the case of a normally white mode liquid crystal display element. Can be offset by reducing the energy of the effective voltage, the decrease in the screen brightness of the heating region,
Therefore, it is possible to compensate for a difference in screen luminance caused by a change in the response characteristic of the liquid crystal in the temperature rising region of the liquid crystal display element 1, and to obtain a display with high quality and substantially uniform screen luminance.

The selection period of the scan electrode 4 and the energy of the effective voltage of the pixel section corresponding to the scan electrode 4 will be described. The relationship between the selection period of each scan electrode 4 and the number of clock pulses when the number is 8, and the energy ratio of the effective voltage of the pixel portion corresponding to each scan electrode 4 is shown.

[0049]

[Table 1]

In Table 1, a liquid crystal display element (liquid crystal display element having 240 scanning electrodes), which is time-divisionally driven at a duty of 1/240, is used for a selection period of each scanning electrode 4.
The field frequency is 120 Hz, the value is when driving is performed with the assignment period of each scanning electrode 4 in one field being about 34.70 μsec, and the number of clock pulses is the value when using a 30 MHz clock pulse.

As shown in Table 1, the selection period of the ninth and subsequent scanning electrodes 4 counted from the side close to the light source 13 is about 34, which is the same as the allocation period in one field evenly allocated to all the scanning electrodes 4. .70 μsec (number of clock pulses = 104
2), and the energy ratio of the effective voltage of the pixel portion corresponding to these scanning electrodes 4 is 100%, but the first to eighth counting from the scanning electrode in the heating region, that is, the side closer to the light source 13. The selection period of the scan electrodes 4 is shorter than the selection period of the ninth and subsequent scan electrodes 4, and therefore, the effective voltage of the pixel portion corresponding to each of the first to eighth scan electrodes 4 in the temperature-raising region is reduced. The energy ratio is smaller than the energy ratio of the effective voltage of the pixel portion corresponding to the ninth and subsequent scan electrodes 4.

The selection period of each of the first to eighth scanning electrodes 4 in the heating region is shorter for the scanning electrode 4 on the high temperature side closer to the light source 13, and accordingly, the first to eighth scanning electrodes 4 in the heating region are shorter. The energy ratio of the effective voltage of the pixel portion corresponding to each of the eighth scanning electrodes 4 becomes smaller as the pixel portion on the higher temperature side closer to the light source 13.

As described above, the selection period of the scanning electrode 4 in the temperature rising region near the light source 13 of the liquid crystal display element 1 is controlled to be shorter than the selection period of the scanning electrode 4 in the other region. When the energy of the effective voltage of the liquid crystal display element 1 is smaller than the energy of the effective voltage of the pixel portion in the other region, the response characteristic changes due to a change in physical characteristics such as a decrease in the viscosity of the liquid crystal in the temperature rising region of the liquid crystal display element 1. However, since the energy of the effective voltage of the pixel portion in the heating region is offset by the small energy, the luminance difference of the screen caused by the change in the response characteristic of the liquid crystal in the heating region of the liquid crystal display element 1 is compensated. Can be.

Therefore, according to this liquid crystal display device,
Due to the heat generated by the light source 13 of the lighting means 12 and the temperature rise in the area of the liquid crystal display element 1 close to the light source 13, there is almost no difference in the luminance of the screen of the liquid crystal display element 1, and the screen luminance is made almost uniform, In addition, it is possible to obtain a high quality display with uniform contrast.

In addition, as described above, the temperature of the liquid crystal display element 1 rises with a constant temperature gradient in which the temperature increases as the distance to the light source 13 increases. Since the selection period of each scanning electrode 4 in the heating region is controlled to be shorter for the scanning electrode 4 on the higher temperature side in accordance with the temperature gradient of the heating region, the screen brightness can be made more uniform. Can be.

The above liquid crystal display device is a transmission type liquid crystal display device provided with an illuminating means 12 behind the liquid crystal display device 1. In the first embodiment, however, the liquid crystal display device is provided before or after the simple matrix liquid crystal display device. A light source disposed on the side along the direction perpendicular to the length direction of the scanning electrode of the liquid crystal display element, and disposed opposite to the front or rear surface of the liquid crystal display element, A light guide plate that takes in the light emitted from the light source from the end face and emits the light toward the liquid crystal display element from the front surface or the rear surface is provided on the rear side of the liquid crystal display element from the front side. A reflection / transmission type liquid crystal display device in which an illuminating means having a function of reflecting incident light and a function of emitting illumination light toward the liquid crystal display element, or a front side and a rear side of the liquid crystal display element, Incident light The function and the illumination light to the bulk liquid crystal display emits toward the device disposed illumination means and a function can be applied to a reflective liquid crystal display device which utilizes both external light and illumination light.

FIGS. 5 and 6 show a second embodiment of the present invention. FIG. 5 is a side view of an electronic apparatus having a liquid crystal display device, and FIG. 6 is a schematic configuration diagram of the liquid crystal display device. is there.

The electronic device shown in FIG.
2 and a lid 23 having a lower end pivotally supported at the rear edge of the personal computer body 22 via a hinge 24. A liquid crystal display device is provided on the lid 23. .

This liquid crystal display is of a transmissive type, and the simple matrix liquid crystal display 1 and the illuminating means 12 provided behind the liquid crystal display 1 are of the type described in the first embodiment. Since the description is the same as that of FIG.

In the liquid crystal display device of this embodiment, the tilt angle of the screen of the liquid crystal display element 1 is adjusted by rotating the opening / closing lid 23 in the opening / closing direction. The illuminating means 12 provided is provided with the open / close lid 23.
With the hinge 24 pivotally supporting the personal computer body 22 as a fulcrum, that is, the length direction of the scanning electrode 4 (the left-right direction of the screen).
Is tilted in the front-rear direction.

In this liquid crystal display device, since the liquid crystal display element 1 is provided so as to be tiltable in the front-rear direction about the length direction of the scanning electrode 4, the inclination angle of the liquid crystal display element 1 in the front-rear direction is determined. Accordingly, the viewing angle of each region along the direction orthogonal to the length direction of the scanning electrode 4, that is, the vertical direction of the screen changes.

That is, the liquid crystal display element 1 is designed such that the optimum viewing angle at which the display can be observed in the brightest and high-contrast state is in the front direction (direction near the normal of the screen). Since the tilt angle of the liquid crystal display element 1 is adjusted according to the preference of the display observer, the viewing angle of each area along the vertical direction of the screen changes according to the tilt angle of the liquid crystal display element 1 in the front-back direction. .

For example, when the liquid crystal display element 1 is observed from a normal observation position (the height of the observer's eyes) A as shown by a solid line in FIG. (A viewing angle of about 90 ° with respect to the screen), the viewing angle decreases continuously from the central region of the screen toward the upper edge and the lower edge.

At this time, the difference between the viewing angles θ1 and θ2 of the upper edge area and the lower edge area with respect to the viewing angle θ0 of the central area depends on the vertical width of the screen. In the case of the liquid crystal display element 1 provided in 23, the difference is relatively small.

On the other hand, when the liquid crystal display element 1 is tilted backward from the above tilted state, the position observed at the optimum viewing angle when observed from the normal observation position A is shifted toward the lower edge of the screen. The viewing angle θ1 in the upper edge area of the screen is further reduced, and the viewing angle θ2 in the lower edge area of the screen is closer to the optimal viewing angle.

The tilt state of the liquid crystal display element 1 shown by a chain line in FIG. 5 is a state in which the viewing angle θ2 at the lower edge of the screen is at the optimum viewing angle, and the liquid crystal display element 1 is tilted further backward. Then, the viewing angle θ1 in the upper edge area of the screen becomes smaller, and the viewing angle θ2 in the lower edge area of the screen becomes smaller than the optimum viewing angle again.

Therefore, if the selection period of all the scanning electrodes 4 of the liquid crystal display element 1 is the same, each area along the vertical direction of the screen which changes according to the tilt angle of the liquid crystal display element 1 in the front-back direction. Is an external factor, and a difference is generated between the screen luminance of the area observed at a viewing angle having a small difference with respect to the optimum viewing angle and the screen luminance of the area observed at a viewing angle with a large difference with respect to the optimum viewing angle.

When the viewing angle θ0 of the central area of the screen when the liquid crystal display element 1 is viewed from the normal viewing position A is at the inclination angle at which the viewing angle becomes the optimum viewing angle as shown by the solid line in FIG. The difference in brightness between the central region of the screen viewed at a viewing angle with a small difference with the optimum viewing angle and the upper and lower edge regions of the screen viewed at a viewing angle with a large difference with the optimum viewing angle is relatively small.

However, when the liquid crystal display element 1 is tilted backward as shown by a chain line in FIG. 5 from that state, the lower edge region of the screen observed at a viewing angle having a large difference from the optimum viewing angle, The difference in brightness from the upper edge area of the screen viewed at a viewing angle having a large difference with the viewing angle increases, and the display quality deteriorates.

Therefore, in this embodiment, a selection signal and a data signal are supplied to the plurality of scanning electrodes 4 and the signal electrodes 5 of the liquid crystal display element 1, respectively, and all the scanning electrodes 4 are sequentially selected in one field. A selection period in which the selection signal is supplied to each scanning electrode 4 within an allocation period allocated to each scanning electrode 4 is observed at a viewing angle having a large difference with respect to the optimum viewing angle among the regions along the vertical direction of the screen. The driving unit 25 controls the scanning electrode 4 in a region where the scanning electrode 4 is selected for a longer period than the selection period of the scanning electrode 4 in a region where the difference from the optimum viewing angle is observed at a smaller viewing angle.

As shown in FIG. 6, the driving means 25 includes a scanning drive circuit 26 for supplying a selection signal to each of the plurality of scanning electrodes 4 of the liquid crystal display element 1 and a plurality of driving circuits for the liquid crystal display element 1. A signal-side drive circuit 27 for supplying a data signal to each of the signal electrodes 5;
A control circuit 28 for controlling the signal side driving circuit 27 and an angle sensor 29 for measuring the tilt angle of the liquid crystal display element 1.

The driving means 25 is provided for the liquid crystal display element 1.
Are supplied to the plurality of scanning electrodes 4 and the signal electrodes 5, respectively, and the selection period of each scanning electrode 4 in the allocation period in one field (period for sequentially selecting all the scanning electrodes 4) is set. In accordance with a difference in viewing angle, which is an external factor that causes a difference in brightness on the screen of the liquid crystal display device 1, control is performed to compensate for a difference in brightness on the screen due to the difference in viewing angle.

That is, the control circuit 28 sends the clock pulse to the scanning side driving circuit 26 and the signal side driving circuit 27.
And display data corresponding to an image signal supplied from the outside to the signal side driving circuit 27.

The signal side drive circuit 27 counts the number of clock pulses for the assigned period assigned to each scan electrode 4 and synchronizes with the assigned period of each scan electrode 4 corresponding to the count of the number of clock pulses. Then, a data signal having a potential corresponding to the display data is supplied to each signal electrode 5 of the liquid crystal display element 1.

The scanning side drive circuit 26 counts the allocation period by the number of clock pulses,
The selection period of each scanning electrode 4 is set to a predetermined time so as to compensate for the brightness difference of the screen due to the difference in viewing angle of each region along the vertical direction of the screen of the liquid crystal display element 1, and each scanning period is set in the allocation period. A selection period preset for each electrode 4 is measured by the number of clock pulses, and a selection signal is supplied to each scanning electrode 4 only during the selection period.

The tilt angle adjustment range of the liquid crystal display element 1 in the front-rear direction is determined by the upper surface (horizontal plane) of the personal computer main body 22.
When the display is observed from a normal observation position A, when the tilt angle of the liquid crystal display element 1 is not less than about 100 ° and less than about 108 °, FIG.
As shown by the solid line, the viewing angle θ0 in the central area of the screen becomes the optimum viewing angle, and the tilt angle of the liquid crystal display element 1 is about 117 °.
When the angle is not more than about 200 °, the viewing angle θ1 at the upper edge of the screen becomes the optimum viewing angle as indicated by the chain line in FIG.

Therefore, in this embodiment, the liquid crystal display element 1
Are equal to each other when the tilt angle of the liquid crystal display element 1 is greater than about 100 ° and less than about 108 °. The number of clock pulses corresponding to the selection period of each scanning electrode 4 is set so as to be gradually longer from the center of the screen toward the upper edge and to be gradually shorter from the center of the screen toward the lower edge.

Note that the change in the viewing angle corresponds to the tilt angle of the liquid crystal display element 1. When the tilt angle of the liquid crystal display element 1 is changed by a fixed angle, the tilt of the liquid crystal display element 1 in an almost vertical angle range is obtained. Although the change in the viewing angle with respect to the change in the angle is small, when the tilt angle of the liquid crystal display element 1 increases, the change in the viewing angle with respect to the change in the tilt angle increases.

For this reason, in this embodiment, the tilt angle of the liquid crystal display element 1 is, for example, about 100 ° or more and less than about 108 °, about 108 ° or more about 113 °, or about 113 ° or more and about 11 °.
7 °, 117 ° or more and about 120 ° or less, the angle range is divided into a plurality of stages so as to decrease as the tilt angle increases, and each scanning electrode 4 is selected for each of the divided angle ranges. The number of clock pulses corresponding to the period is set.

That is, in this embodiment, when the tilt angle of the liquid crystal display element 1 is about 100 ° or more and less than about 108 °, the number of clock pulses corresponding to the selection period of each scanning electrode 4 is all set to be the same. The tilt angle is about 108 ° or more and about 113
°, the number of clock pulses corresponding to the selection period of each scanning electrode 4 is sequentially increased by 1 from the center of the screen toward the upper edge.
A clock pulse corresponding to a selection period of each scanning electrode 4 when the tilt angle is set to be longer by one pulse and shorter by one pulse from the center of the screen toward the lower edge side, and the inclination angle is about 113 ° or more and about 117 °. The number is set to be longer by two pulses sequentially from the center of the screen toward the upper edge side and shorter by two pulses sequentially from the center of the screen toward the lower edge side, and the inclination angle is about 117 ° or more and about 120 ° or less. Each scanning electrode 4 at a certain time
The number of clock pulses corresponding to the selection period is sequentially set to be longer by three pulses from the center of the screen toward the upper edge, and to be shorter by three pulses sequentially from the center of the screen toward the lower edge.

The number of clock pulses corresponding to the selection period of each of the scanning electrodes 4 is set within the range of the number of clock pulses in the allocation period of each of the scanning electrodes 4.
Among them, the number of clock pulses corresponding to the selection period of the scan electrode 4 in which the selection period is set to be the longest is set to be the same as the number of clock pulses in the allocation period.

In this embodiment, the number of clock pulses corresponding to the selection period of each scanning electrode 4 set for each tilt angle is stored in the scanning side driving circuit 26,
From among them, the number of clock pulses corresponding to the tilt angle of the liquid crystal display element 1 measured by the angle sensor 29 is selected, and each scanning electrode 4 of the liquid crystal display element 1 is selected according to the tilt angle measured by the angle sensor 29. The selection time is controlled.

This liquid crystal display device has the liquid crystal display element 1
The difference in the viewing angle of each region along the vertical direction of the screen (the direction orthogonal to the length direction of the scanning electrode 4) due to the adjustment of the tilt angle in the front-rear direction of the screen causes the brightness difference on the screen of the liquid crystal display element 1. As an external factor to cause, the liquid crystal display element 1 is
Of the regions along the direction perpendicular to the vertical direction of the screen, the scanning electrode selection period of the region observed at a viewing angle with a large difference with the optimal viewing angle is observed at a viewing angle with a small difference with the optimal viewing angle. Since the driving is performed by the driving circuit 25 which controls the scanning electrode in the region longer than the selection period, the simple matrix liquid crystal display element 1 of the STN type is used. A change in the viewing angle hardly causes a difference in brightness on the screen of the liquid crystal display element 1, and a display with good quality and substantially uniform screen brightness can be obtained.

That is, if the selection period of all the scanning electrodes 4 is the same, for example, in the case of a normally black mode liquid crystal display element, the black level of the region observed at a viewing angle having a large difference from the optimum viewing angle rises. In the case of a normally white mode liquid crystal display device, the white level of an area observed at a viewing angle having a large difference from the optimum viewing angle is low.

However, in this embodiment, the selection of the scanning electrodes in the region observed at a viewing angle having a large difference with respect to the optimum viewing angle among the regions along the direction perpendicular to the vertical direction of the screen of the liquid crystal display element 1 is described. Since the period is controlled to be longer than the selection period of the scanning electrode in the region where the difference with respect to the optimal viewing angle is observed at a small viewing angle, the effective voltage of the pixel portion of the region where the difference with respect to the optimal viewing angle is observed at a large viewing angle is controlled. The energy can be made larger than the energy of the effective voltage of the pixel portion in a region observed at a viewing angle where the difference from the optimum viewing angle is small.

Therefore, in the case of the liquid crystal display element of the normally black mode, the rising of the black level in the region observed at the viewing angle having a large difference from the optimum viewing angle is offset by increasing the energy of the effective voltage, and the normally black mode is compensated. In the case of a white mode liquid crystal display device, a decrease in white level in a region observed at a viewing angle having a large difference from the optimum viewing angle can be offset by reducing the energy of the effective voltage.

Therefore, according to this liquid crystal display device,
The display screen of the liquid crystal display element 1 has almost no luminance difference due to a change in the viewing angle in accordance with the tilt angle of the liquid crystal display element 1, making the screen luminance almost uniform, and obtaining a high quality display with uniform brightness and contrast. be able to.

In addition, the viewing angle decreases continuously from a region observed at a viewing angle having a small difference with respect to the optimum viewing angle to a region observed at a viewing angle having a large difference with respect to the optimum viewing angle. The selection period of each scanning electrode 4 of the liquid crystal display element 1 is controlled so as to be sequentially shortened from a region observed at a viewing angle having a large difference with respect to the optimum viewing angle toward an area observed at a viewing angle having a small difference with respect to the optimum viewing angle. Therefore, the screen brightness can be made more uniform.

Further, in this embodiment, the inclination angle of the liquid crystal display element 1 is measured by an angle sensor 29, and each scanning electrode 4 of the liquid crystal display element 1 is selected according to the inclination angle measured by the angle sensor 29. Since the time is controlled, the difference in screen brightness is automatically compensated for in accordance with the adjustment of the tilt angle of the liquid crystal display element 1, and the screen brightness can be made substantially uniform.

The liquid crystal display device is provided on the opening / closing lid 23 of a notebook personal computer.
Can be applied to, for example, a stand-alone display of a desktop personal computer and a liquid crystal display device such as a liquid crystal television.

In the above embodiment, when the tilt angle of the liquid crystal display element 1 is not less than about 100 ° and less than about 108 °, that is, when the image is observed from the normal observation position A as shown by the solid line in FIG. In the tilted state where the viewing angle θ0 of the central region is at the optimum viewing angle, and the viewing period decreases from the central region of the screen toward the upper edge side and the lower edge side, the selection periods of the respective scanning electrodes 4 are all the same. When the vertical width of the screen is large as in a large-screen liquid crystal display element, each scanning electrode 4 moves from the central area of the screen toward the upper edge side and the lower edge side even in a state where the viewing angle in the central area of the screen is at an optimum viewing angle. It is preferable to sequentially increase the selection period (e.g., increase by one pulse for every two or three scanning electrodes).

Further, in the second embodiment, the number of clock pulses corresponding to the selection period of each scanning electrode 4 set for each tilt angle of the liquid crystal display element 1 is stored in the scanning side drive circuit 26. The number of clock pulses corresponding to the selection period of each scanning electrode 4 at a predetermined inclination angle is stored in the scanning side driving circuit 26 as the number of reference pulses, and the liquid crystal display element 1 measured by the angle sensor 29 is stored. The number of clock pulses for each tilt angle is calculated by increasing / decreasing the reference pulse number at a ratio corresponding to the tilt angle of the liquid crystal display element 1 according to the tilt angle measured by the angle sensor 29. The selection time of the electrode 4 may be controlled.

In the second embodiment, the driving means 2
5 is provided with the angle sensor 29, and the angle sensor 2
Although the configuration is such that the selection time of each scanning electrode 4 of the liquid crystal display element 1 is controlled in accordance with the tilt angle measured by 9, the driving unit 25 is a manually operated brightness adjustment unit (for example, a manual slide knob). And a configuration in which the selection time of each of the scanning electrodes 4 is controlled according to the operation of the luminance adjustment unit.

Further, the liquid crystal display device is a transmissive liquid crystal display device provided with an illuminating means 12 behind the liquid crystal display device 1. In the second embodiment, the liquid crystal display device is provided behind the simple matrix liquid crystal display device. A reflection / transmission type liquid crystal display device in which illumination means having a function of reflecting incident light from the front side and a function of emitting illumination light toward the liquid crystal display element, or a front side of the liquid crystal display element, Arranging illumination means having a function of transmitting incident light from the rear side and a function of emitting illumination light toward the liquid crystal display element, a reflection type liquid crystal display device using both external light and illumination light is also provided. ,Also,
The present invention can also be applied to a liquid crystal display device that includes a reflection unit on the rear side of the liquid crystal display element and performs only reflection display using external light incident from the front side, which is the display observation side.

As in the above-mentioned transmission type, reflection / transmission type, and reflection type liquid crystal display devices using both external light and illumination light,
A light source disposed on one of the front and rear sides of the liquid crystal display element, along the side thereof along a direction perpendicular to the length direction of the scanning electrode of the liquid crystal display element, and a front or rear surface of the liquid crystal display element In the case of a liquid crystal display device provided with lighting means comprising a light guide plate which is disposed to face the light emitted from the light source from an end face and emits the light toward the liquid crystal display element from the front surface or the rear surface, Not only the viewing angle difference of each area along the direction perpendicular to the scanning electrode length direction of the screen of the liquid crystal display element, but also the temperature rise of the area near the light source of the liquid crystal display element due to the heat generated by the light source of the illuminating means. This is an external factor that causes a luminance difference on the screen of the liquid crystal display element.

Therefore, when the second embodiment is applied to a liquid crystal display device provided with the illuminating means, the driving means 25 is provided with each of the components along the direction orthogonal to the scanning electrode length direction of the screen. A function of controlling the scanning electrode selection period of the region observed at a large viewing angle having a difference with respect to the optimal viewing angle longer than the scanning electrode selection period of the region observed at a small viewing angle with respect to the optimal viewing angle. The selection period of the scanning electrode in a region near the light source of the liquid crystal display element,
It is preferable to have both the function of controlling the scan electrode in the other area shorter than the selection period, and in this way, in the direction orthogonal to the scan electrode length direction of the screen of the liquid crystal display element. Both the screen brightness difference caused by the difference between the viewing angles of the respective areas along the screen as an external factor and the screen brightness difference caused by the temperature increase of the area near the light source of the liquid crystal display element as an external factor are compensated for, and the screen brightness is compensated. However, it is possible to obtain an almost uniform display of good quality.

The liquid crystal display devices of the first and second embodiments have the STN type simple matrix liquid crystal display device 1. The present invention is directed to the TN type simple matrix liquid crystal display device 1. The present invention can also be applied to a liquid crystal display device having

[0098]

According to the liquid crystal display device of the present invention, a simple matrix liquid crystal display element is supplied with a selection signal and a data signal to a plurality of scanning electrodes and the scanning electrodes of the liquid crystal display element, and all the scanning electrodes are sequentially connected. A selection period in which the selection signal is supplied to each scanning electrode within an allocation period allocated to each scanning electrode in one field to be selected is determined according to an external factor that causes a luminance difference on a screen of the liquid crystal display element. It is driven by a driving unit that controls so as to compensate for the luminance difference of the screen due to the external factor,
It is possible to substantially eliminate the occurrence of a difference in luminance on the screen of the liquid crystal display element due to the external factor, and to obtain a display of high quality with substantially uniform screen luminance.

In the liquid crystal display device according to the present invention, the liquid crystal display device is arranged on one of the front and rear sides thereof so as to extend along the direction perpendicular to the length direction of the scanning electrode of the liquid crystal display device. And a light guide plate disposed opposite to the front or rear surface of the liquid crystal display element and receiving light emitted from the light source from an end face and emitting the light from the front or rear surface toward the liquid crystal display element. When the means is provided, an external factor that causes a luminance difference on the screen of the liquid crystal display element is a temperature rise in a region near the light source of the liquid crystal display element due to heat generated by the light source of the lighting means. The driving unit may be configured to control the selection period of the scanning electrode in the region of the liquid crystal display element close to the light source to be shorter than the selection period of the scanning electrode in the other region. The display of the liquid crystal display device compensates for the brightness difference of the screen caused by the difference of the viewing angle of each area along the direction orthogonal to the scanning electrode length direction of the screen as an external factor, and the screen brightness is almost uniform and high quality display. Can be obtained.

In this case, it is desirable that the driving means controls the scanning electrode on the higher temperature side so as to shorten the selection period in accordance with the temperature gradient of the temperature rising region of the liquid crystal display element. By doing so, the screen luminance can be made more uniform.

In the liquid crystal display of the present invention,
When the liquid crystal display element is provided so as to be tiltable in the front-rear direction around the length direction of the scanning electrode, an external factor that causes a luminance difference on the screen of the liquid crystal display element is the scanning electrode length of the screen. Since the difference between the viewing angles of the respective regions along the direction perpendicular to the vertical direction is different from the optimum viewing angle among the respective regions along the direction perpendicular to the scanning electrode length direction of the screen. The selection period of the scanning electrodes in the region observed with a large viewing angle may be controlled to be longer than the selection period of the scanning electrodes in the region observed with a small viewing angle with respect to the optimal viewing angle. This compensates for the difference in screen brightness caused by the difference in the viewing angle of each region along the direction perpendicular to the scanning electrode length direction of the screen of the liquid crystal display element as an external factor, and the screen brightness is substantially uniform. To get a good display of Can.

In this case, the driving means sets the selection period of each scanning electrode of the liquid crystal display element from a region where the difference with respect to the optimum viewing angle is observed at a large viewing angle to a region where the difference with respect to the optimum viewing angle is observed at a small viewing angle. It is desirable to adopt a configuration in which the control is performed so as to be sequentially shortened toward the screen. By doing so, the screen luminance can be made more uniform.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a side view of the liquid crystal display device.

FIG. 3 is a sectional view of a part of the simple matrix liquid crystal display element 1.

FIG. 4 is a waveform diagram of a selection signal supplied to each scanning electrode of the liquid crystal display element.

FIG. 5 is a side view of an electronic apparatus including a liquid crystal display device according to a second embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of a liquid crystal display device according to a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Simple matrix liquid crystal display element 2, 3 ... Substrate 4 ... Scan electrode 5 ... Signal electrode 9 ... Liquid crystal layer 12 ... Illumination means 13 ... Light source 16 ... Light guide plate 17 ... Drive means 18 ... Scan side drive circuit 19 ... Signal side drive Circuit 20 Control circuit 22 Personal computer 23 Opening / closing lid 24 Hinge 25 Driving means 26 Scanning drive circuit 27 Signal drive circuit 28 Control circuit 29 Angle sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09G 3/36 G09G 3/36 F term (Reference) 2H093 NA07 NA43 NB21 NC09 NC48 NC49 NC52 NC63 NC65 ND05 ND09 ND13 ND58 NE06 NF13 5C006 AC02 AF42 AF46 AF62 BB12 BF22 BF38 FA19 FA22 5C080 AA10 BB05 CC10 DD30 EE28 FF09 JJ02 JJ04 JJ06

Claims (5)

[Claims] A plurality of scanning electrodes are provided on one inner surface of a pair of front and rear substrates opposed to each other with a liquid crystal layer interposed therebetween in a row direction,
A simple matrix liquid crystal display element provided with a plurality of signal electrodes along the column direction on the inner surface of the other substrate, and a selection signal and a data signal supplied to the plurality of scanning electrodes and the signal electrodes of the liquid crystal display element, respectively. The selection period in which the selection signal is supplied to each scanning electrode within the allocation period allocated to each scanning electrode in one field for sequentially selecting the scanning electrodes is selected as an external period that causes a luminance difference on the screen of the liquid crystal display element. A liquid crystal display device comprising: a driving unit that performs control so as to compensate for a luminance difference of a screen due to the external factor according to a factor. 2. A light source arranged on one of the front and rear sides of a liquid crystal display element and along one side thereof in a direction perpendicular to a length direction of a scanning electrode of the liquid crystal display element; Illumination means is provided, which is disposed to face the front or rear surface of the element, and a light guide plate that takes in light emitted from the light source from an end surface and emits the light toward the liquid crystal display element from the front or rear surface. 2. The liquid crystal display device according to claim 1, wherein the driving unit controls a selection period of a scanning electrode in a region of the liquid crystal display element close to the light source to be shorter than a selection period of a scanning electrode in another region. 3. . 3. The driving device according to claim 2, wherein the driving means controls the scanning electrode on the higher temperature side to shorten the selection period in accordance with the temperature gradient in the temperature rising region of the liquid crystal display element. Liquid crystal display. 4. A liquid crystal display device is provided so as to be tiltable in the front-rear direction with respect to a length direction of a scanning electrode, and a driving means is provided in a direction orthogonal to the scanning electrode length direction of the screen. The selection period of the scanning electrode in the region observed at a viewing angle having a large difference with respect to the optimum viewing angle is controlled to be longer than the selection period of the scanning electrode in the region observed at a viewing angle having a small difference with respect to the optimum viewing angle. The liquid crystal display device according to claim 1, wherein: 5. The driving means sets the selection period of each scanning electrode of the liquid crystal display element from a region observed at a viewing angle having a large difference with respect to the optimum viewing angle to a region observed at a viewing angle having a small difference with respect to the optimum viewing angle. The liquid crystal display device according to claim 4, wherein the control is performed so as to be sequentially shortened.