JP2773748B2 - Liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a liquid crystal display device that displays an image by applying a voltage to each part of a liquid crystal cell, with the object of improving the visibility of display in an edge region of a display screen, A liquid crystal display device comprising: a liquid crystal cell in a layered form; and image display voltage applying means for displaying an image by applying a predetermined voltage corresponding to an image to each portion in a predetermined region of the liquid crystal cell. In the liquid crystal cell, the liquid crystal cell may be configured to have a peripheral region voltage applying means for applying a voltage to a region around the predetermined region, or a liquid crystal cell including a layered liquid crystal substance, and one of the liquid crystal cells. And an incident light polarization state setting unit for setting the polarization state of light incident on the liquid crystal cell to a predetermined state, and the liquid crystal cell provided on the other side of the liquid crystal cell. In a liquid crystal display device having a liquid crystal passing light polarization state selection unit that passes only a component of a predetermined polarization state of the transmitted light, and displays an image in a predetermined region of the liquid crystal cell, in the liquid crystal cell, The thickness of the layer of the liquid crystal material is different between a predetermined area for displaying the image and an area surrounding the predetermined area.

[Industrial applications]

The present invention relates to a liquid crystal display device that displays an image by applying a voltage to each part of a liquid crystal cell.

2. Description of the Related Art A display device using a liquid crystal material whose optical characteristics are changed by applying a voltage is generally widely used.

There are several types of liquid crystal display devices as described above, but a display area around a display screen is not in a display state equal to the background of the screen, but is equal to a positive display (character or graphic display) on the display screen. Some are used in state.

For example, an STN (Super Twisted Nematic) type liquid crystal display device using a STN (Super Twisted Nematic) type liquid crystal cell in which linearly polarized light is incident and twisted by 90 ° or more, and a twist angle of 1 °
In an SBE (Liquid Crystal Display) device using an SBE (Super Biafringence Effect) type liquid crystal cell of 80 mm or more, in order to improve image contrast, the STN or SBE type liquid crystal cell must have a predetermined threshold or more. May be used in a mode in which the display becomes white when a voltage of?

However, if the partial display state around the display screen is equal to the positive display on the display screen,
Alternatively, in a display device having substantially the same display state, the visibility of the display in the edge region in the display screen adjacent to the region around the display screen is reduced.

Therefore, there is a demand for a technology that solves the problem of the reduction in the visibility of the display at the end portion in the display screen.

[Conventional technology and problems to be solved by the invention]

FIG. 20 schematically shows a configuration for applying a voltage to a liquid crystal material in a conventional simple matrix type liquid crystal display device as an example of a display device using the above-mentioned liquid crystal material.

20, 10 and 20 are upper and lower glass substrates, respectively, 30 is a liquid crystal cell, 12 ₁ , 12 ₂ ,... 12 _n are transparent column electrodes, and 22 ₁ , 22 _{2 ,.} Is a transparent row electrode.

The liquid crystal cell 30 is sandwiched between the upper and lower glass substrates 10 and 20 to form a layer. The column electrodes 12 ₁ , 12 ₂ ,
.. _12n are provided on the liquid crystal cell 30 side of the upper glass substrate 10 and serve as electrodes for applying a voltage to a liquid crystal material in a region corresponding to a pixel in each column of a screen displaying an image in the liquid crystal cell 30. Of the row electrode 22
₁ , 22 ₂ ,..., 22 _n are the liquid crystal substances 30 of the lower glass substrate 20.
And is the other side of the electrode when a voltage is applied to the liquid crystal material in a region corresponding to a pixel of each row of a screen displaying an image in the liquid crystal cell 30.

In the liquid crystal cell 30, column electrodes 12 _1, 12 _2, of ... 12 _n 1
The liquid crystal material in a region sandwiched by one of the row electrodes 22 ₁ , 22 ₂ ,..., 22 _n changes the optical characteristics according to the voltage applied between these electrodes, thereby forming one pixel for each pixel. The display is performed.

The plurality of row electrodes and the plurality of column electrodes become a plurality of scanning electrodes and a plurality of signal electrodes, respectively, assuming raster scanning in normal image display. FIG. 21 is a plan view of a conventional liquid crystal display device having a simple matrix type electrode as shown in FIG.

In the upper substrate 10 shown in FIG. 21, the portion _where the arrangement of the plurality of signal electrodes 12 ₁ , 12 ₂ ,... 12 _n densely exists as shown in FIG. On the lower substrate 20 in FIG. 21, a plurality of scan electrodes 22 as shown in FIG.
₁ , 22 ₂ ,..., 22 _n
Shown as two.

An area where the signal electrode section 12 and the scanning electrode section 22 intersect is the display section 5 which is an area for displaying an image.
The non-display portion 6 is a region that can be seen around.

The liquid crystal display device using the STN-type or SBE-type liquid crystal cell described above has a characteristic that the transmittance changes sharply with respect to a change in applied voltage in a predetermined range as shown in FIG. In recent years, the present applicant and others have studied this technology because a large-capacity screen display can be realized by a simple matrix configuration having a simple configuration, low cost, and good yield.
Japanese Patent Application No. 62-235345).

By the way, in this STN or SBE liquid crystal display device, an STN or SBE liquid crystal cell is
In a mode in which the polarizer is sandwiched between two orthogonal polarizing plates and has a yellow-green color when a voltage equal to or higher than a predetermined threshold is not applied, and is black when a voltage equal to or higher than the predetermined threshold is applied, the background is positive. It is difficult to distinguish from a proper display. Therefore, ST
A mode is used in which an N-type or SBE-type liquid crystal cell is sandwiched between two polarizing plates whose polarization directions are parallel, and blue when no voltage is applied and white when a voltage is applied. (Japanese Patent Application No. 62
For the −235345 panel, black when no voltage is applied,
It turns white when voltage is applied. As described above, in the liquid crystal display device having the matrix configuration as described above, the liquid crystal material in the region around the region displaying the pixel is not sandwiched between the two electrodes.
No voltage is applied. Therefore, the surrounding area is always (almost) blue and black (see FIG. 22).

The display of the screen is a positive display, that is, for example,
When the character portion is black and the background is white, the visibility of the black display of the pixel at the end of the display screen adjacent to the area around the display screen is reduced.

Such an example is shown in FIG. That is,
In FIG. 23, characters “H” and “A” are displayed at the end of the display screen (display section 5) in contact with the area around the display screen (non-display section 6). These can be mistaken for each other. Similarly, although not shown, “U” and “O” may be erroneously recognized from each other.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal display device that improves the visibility of a display in an edge region of a display screen.

[Means for solving the problem]

FIG. 1 is a block diagram showing the principle of the first embodiment of the present invention. In this figure, 2 is an image display voltage applying means, 3 is a liquid crystal cell, and 4 is a surrounding area voltage applying means.

The image display voltage applying means 2 displays an image by applying a voltage to each area in a predetermined area (indicated by 5 in FIG. 1) of the liquid crystal cell 3.

The surrounding region voltage applying means 4 is a region around the above-mentioned region 5 of the liquid crystal cell 3 (indicated by 6 in FIG. 1).
Voltage.

FIG. 2 is a block diagram showing the principle of the second embodiment of the present invention. In the figure, 1 ₁ is the incident light polarization state setting unit, 1 ₂ LCD passes light polarization state selecting unit, 3 'liquid crystal cell, the liquid crystal cell 3 is 5' predetermined area for displaying an image in, and, 6 Is a region around the predetermined region 5.

The incident light polarization state setting unit 1 ₁ sets the polarization state of light incident on the liquid crystal cell 3 'to a predetermined state. Then, the liquid crystal passes light polarized state selecting unit 1 ₂ is intended to only pass component in a predetermined polarization state of the light passing through the liquid crystal cell 3 ',
The incident light polarization state setting unit 1 ₁ and the liquid crystal passes light polarized state selecting unit 1 ₂ is provided on both sides of the liquid crystal cell 3 '.

In the liquid crystal cell 3 ′, the thickness of the layer of the liquid crystal material is different between a predetermined area 5 for displaying the image and an area 6 surrounding the area 5.

(Operation)

According to the first embodiment of the present invention shown in FIG. 1, the surrounding area voltage applying means 4 applies a voltage also to the area 6 around the area 5 in the liquid crystal cell 3 where an image is displayed, whereby The display state of the surrounding area 6 can be approximated to the display state of the background of the display screen corresponding to the display state when a voltage equal to or higher than a predetermined threshold is applied to the liquid crystal cell.

Further, according to the second embodiment of the present invention shown in FIG. 2, the thickness of the liquid crystal material layer (the liquid crystal cell) in the predetermined area 5 for displaying an image and the area 6 surrounding the area 5 3 '
Thickness).

The liquid crystal cell 3 'has a layered shape, and changes the polarization state of light incident on the layer according to the applied voltage according to the thickness of the light incident on the layer.

Therefore, among incident on the liquid crystal cell 3 'after the incident light polarization state setting unit 1 ₁ is set to a predetermined polarization state of light, and the polarization state of light passing through the predetermined region 5 for displaying an image, the The polarization state of the light that has passed through the region 6 around the region 5 differs depending on the above-described thickness difference (that is, the thickness difference).

Therefore, by setting this thickness appropriately,
The above two kinds of differences in intensity of the component of the predetermined polarization state in which the receiving passing light liquid passing light polarized state selecting unit 1 ₂ pass occurs, be to the extent that a clear difference with the naked eye It becomes possible.

That is, the difference in light transmittance between a pixel area displaying a positive portion such as a character in a predetermined area 5 for displaying an image and an area 6 surrounding the predetermined area 5 for displaying the image is determined with the naked eye. Can be made clearer.

Therefore, the visibility of the display is improved especially at the end of the predetermined area 5 where the image is displayed.

〔Example〕

FIGS. 3A and 3B are cross-sectional views of a STN-type liquid crystal display device having two liquid crystal cells, as viewed from two orthogonal directions, as a first embodiment of the present invention.

3A and 3B, reference numerals 30 ₁ and 30 ₂ denote liquid crystal material layers, 31 ₁ and 31 ₂ denote polarizing plates, 32 ₁ , 32 ₂ , 32 ₃ , and 32 ₄ denote glass substrates, 33 ₁ , 33 ₂ , 33 ₃ and 33 ₄ are alignment films, 34 ₁ , 34 ₂ , 34 ₃ and 34 ₄
Is a sealing material, 12 ₁ , 12 ₂ , 12 ₃ are also transparent signal electrodes (actually more) composed of ITO electrodes, etc., 22 ₁ , 22 ₂ , 22 ₃ are ITO
According to the first embodiment of the present invention, transparent scanning electrodes (actually, a larger number of electrodes), such as electrodes, are provided. Peripheral column electrodes provided as the peripheral region voltage applying means 4 for applying a voltage to the display unit 6;
21 and 23, which are also peripheral row electrodes provided in accordance with the first embodiment of the present invention, are also transparent electrodes made of ITO electrodes or the like.

Will have a layer 30 ₁ and 30 ₂ is equal thickness of the liquid crystal material, and in the orientation film 33 _1, 33 _2, 33 _3, 33 _4, alignment treatment in the appropriate direction, respectively is performed, thereby The light incident on the _first liquid crystal material layer 301 through the polarizing plate 31 ₁ and passing through the _first liquid crystal material layer 301 undergoes a predetermined change in polarization state (refraction of the liquid crystal material). By appropriately selecting the rate, the thickness of the liquid crystal material layer, and other parameters,
For example, the light that has passed through the _first liquid crystal
It can be converted into elliptically polarized light that is close to linearly polarized light that has been rotated by 70 °), but this light is converted into a second liquid crystal material layer 30.
When entering the _2, in the layer 30 ₂ of the second liquid crystal material, subject to change just opposite polarization states of those who received the layer 30 ₁ of the first liquid crystal material, thereby, When the light passes through the _second liquid crystal material layer 302 and reaches the polarizing plate 31 ₂ , the light returns to linearly polarized light similar to that immediately after passing through the polarizing plate 31 _1. I do. By doing so, the phase difference of light having a different polarization state (elliptical polarization) for each wavelength of light by passing through the first liquid crystal cell can be compensated, and the display is colored. It is known that black and white display can be prevented.

In addition, the first liquid crystal cell composed of the layer 30 ₁ of the first liquid crystal material sandwiched between the orientation films 33 ₁ and 33 _2, the signal electrode 12 respectively formed on the glass substrate 32 ₁ and 32 _{2 1} ,
Voltages for forming an image are applied by the electrodes 12 ₂ , 12 ₃ and the scanning electrodes 22 ₁ , 22 ₂ , 22 ₃ .

In the configuration of Figures 3A and Figure 3B, between the signal electrodes 12 _1, 12 _2, 12 ₃ and the scan electrodes 22 _1, 22 _2, 22 ₃ of a predetermined among those, the predetermined described later The direction of the major axis of the elliptically polarized light of the elliptically polarized light of the light that has passed through the first liquid crystal cell when a voltage equal to or higher than the threshold is applied is the direction of the light that has passed through the first liquid crystal cell when no voltage is applied. It can be set so as to be substantially orthogonal to the direction of the major axis of the elliptical polarization ellipse. Accordingly, light passing through a portion of the first liquid crystal cell to which a voltage equal to or higher than the predetermined threshold is applied and light passing through a portion other than the predetermined threshold have a major axis direction of elliptically polarized light, almost 90 ° different states, is incident on the second polarizing plate 31 _2.

In the example of Figures 3A and Figure 3B, the direction of the second polarizing plate 31 _{and second} polarization of light passing through the portion where the predetermined threshold or more voltage is applied in the elliptical polarization of the ellipse In the configuration shown in FIGS. 3A and 3B, a pixel to which a voltage equal to or higher than the predetermined threshold is applied is bright (white), and other pixels are dark (black). ).

In the conventional liquid crystal display device, in the display mode in which the pixels in the background portion of the image are bright (white) and the positive display of characters and the like is dark (black), the background of the image of the first liquid crystal cell is A voltage equal to or higher than the predetermined threshold value is applied only to the pixel portion of the portion, and the surrounding portion of the image becomes blackish as well as the positive display of the characters and the like. Therefore, as shown in FIG. 23, the visibility of the display at the edge of the screen is reduced.

Now, the peripheral column electrodes 11 and 13 and the peripheral row electrodes 21 and 23 in the configuration shown in FIGS. 3A and 3B are respectively provided within the predetermined region 5 of the liquid crystal cell 30 in the first embodiment of the present invention. A surrounding area voltage applying unit 4 (first unit) for displaying an image by applying a predetermined voltage corresponding to the image to each of the portions.
Figure). The peripheral column electrodes 11 and 13 are arranged in a row of a plurality of transparent signal electrodes 12 ₁ , 12 ₂ ,... 12 _n for applying a voltage to a liquid crystal material in a region corresponding to a pixel in each column of a screen displaying an image. Peripheral row electrodes 21 and 23 provided adjacent to both sides
Are a plurality of transparent scanning electrodes for applying a voltage to a liquid crystal material in a region corresponding to a pixel in each row of a screen for displaying an image.
22 _1, 22 ₂ is provided adjacent to both sides of the sequence of ... 22 _n.

State of formation of the electrode in the glass substrate 32 ₁ and the glass substrate 32 on ₂ is as shown in Figures 4A and Figure 4B. The upper substrate 10 in FIG. 4A corresponds to FIGS. 3A and 3B
Corresponding to the glass substrate 32 ₁ in FIG, lower substrate in Figure 4B 2
0 corresponds to the glass substrate 32 ₂ of Figures 3A and Figure 3B.

4A and 4B, the upper substrate 10 and the lower substrate 20
FIG. 5A shows an outline of the configuration in which these are superimposed, and FIG. 5B shows a partially enlarged view of the end of the image display area and the peripheral area.

In FIG. 5B, the areas indicated by “A”, “B”, “C”, and “D” are the scan electrode 22 _n and the signal electrode 12 _n , respectively, and the scan electrode 22 _n and the signal electrode 12 _n−1 , Scan electrode 22 _n-1 and signal electrode 1
2 _n , and a partial area of the liquid crystal cell 30 sandwiched between the scanning electrode 22 _n-1 and the signal electrode 12 _n-1 and corresponds to a pixel for displaying an image. The region indicated by “E” is a partial region of the liquid crystal cell 30 sandwiched between the peripheral row electrode 23 and the signal electrode 12 _i ,
The area indicated by “F” is a partial area of the liquid crystal cell 30 sandwiched between the scanning electrode 22 _j and the peripheral column electrode 13, and the area indicated by “G” is the peripheral column electrode 13 and the peripheral row electrode 23 is a partial region of the liquid crystal cell 30 sandwiched between the liquid crystal cell 23 and the liquid crystal cell 23.

In a conventional liquid crystal display device having a simple matrix configuration, a voltage including an AC component is applied to each of the scanning electrode and the signal electrode, and a region corresponding to each pixel of the liquid crystal cell 30 is, for example, as shown in FIG. A rectangular pulse having a pattern whose phase is inverted at the center as shown is applied. Sixth
In the illustrated example, V ₀ = 30 V, and when the number of scanning lines is 200, a = 15.

In this example, as shown in FIG. 22, the voltage at which the light transmittance of the liquid crystal cell sharply changes according to the change in the applied voltage, that is, the threshold voltage (V _{0N in} FIG. 22) is About 2.5
V.

In the non-selection state of FIG. 6, the amplitude of the rectangular pulse is ± 2 V, and even if such an AC voltage is repeatedly applied to a certain pixel area, the effective voltage applied to the pixel area of the liquid crystal cell is Does not exceed the above threshold. Therefore,
At this time, the transmittance of the pixel region of the liquid crystal cell does not increase.

The rectangular pulse in the semi-selected state in FIG. 6 indicates a voltage applied to the pixel region of the liquid crystal cell sandwiched between the signal electrode not in the selected state and the scanning electrode at the time of selection. The application of the rectangular pulse voltage in the half-selected state to such a pixel region is performed only once in one scanning cycle, and the effective voltage is equal to or less than the threshold value. Therefore, also in this case, the transmittance of the pixel region of the liquid crystal cell does not increase.

The amplitude of the rectangular pulse in the selected state of FIG. 6 is ± 30 V, and when this rectangular pulse is applied once in one scanning cycle,
The effective value of the voltage in the applied pixel region is equal to or higher than the threshold. Therefore, at this time, the transmittance of the pixel region of the liquid crystal cell is significantly increased as shown in FIG. That is, this pixel becomes white.

7A and 7B are diagrams each showing an example of the waveform of the voltage applied to the signal electrode _12i and the scanning electrode _22j when the pattern of FIG. 6 is used. In the liquid crystal cell 30, the pixel region sandwiched between the signal electrode 12 _i and the scanning electrode 22 _j, as shown in FIG. 6, the voltage of FIG. 7B scan electrodes 22 _j, Figure 7A Is applied to the signal electrode _12i .

FIGS. 8A and 8B show the peripheral electrodes (the peripheral column electrodes 11, 13 and the peripheral row electrodes 21, 23 are also collectively referred to as peripheral electrodes) in the first embodiment of the present invention as described above. 1 shows a first example of the applied voltage.

That is, in the example of FIGS. 8A and 8B, the peripheral column electrodes 11 and 13 are respectively provided with the scanning electrodes 22 ₁ , 22 ₂ ,.
_j ... 22 DC component of the voltage applied to _n , that is, 15 V is applied, and signal electrodes 12 ₁ , 12 ₂ ,
… 12 _i … 12 _n DC component of the voltage applied to
V is applied.

When the peripheral electrode voltage of the FIG. 8A and Figure 8B is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrode 12
Assuming that the voltages of the waveforms shown in FIGS. 7B and 7A are applied to ₁ , 12, ₂ ,... 12 _i, 12 _n , the voltage applied to the liquid crystal material in the region E in the configuration of FIG. The result is as shown in Fig. 9A. That is, an AC voltage having an amplitude of ± 13 V to 15 V is applied to the region E. Since this voltage is equal to or higher than the above-mentioned threshold voltage of 2.5 V, the transmittance of the region E in the configuration of FIG. 5B is significantly increased, and this portion looks white.

Also, when the peripheral electrode voltage of the FIG. 8A and Figure 8B is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and FIG. 7A, the voltage of the waveform shown in FIG.
The voltage applied to the liquid crystal material in the region is as shown in FIG. 9B. That is, an AC voltage having an amplitude of ± 13 V to 15 V is also applied to the region F. Since this voltage is also equal to or higher than the above-mentioned threshold voltage of 2.5 V, the transmittance of the region F in the configuration of FIG. 5B is significantly increased, and this portion also looks white.

Further, when the peripheral electrode voltage of the FIG. 8A and Figure 8B is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and FIG. 7A, the voltage of the waveform shown in FIG.
The voltage applied to the liquid crystal material in the region is as shown in FIG. 9C. That is, at this time, the voltage applied to the G region is 0V. Therefore, the transmittance of the region G does not increase, and the color appears to be close to a positive display color (for example, blue in the blue mode and black in the black and white mode).

As described above, in the first example of the voltage applied to the peripheral electrodes shown in FIGS. 8A and 8B, the portion G in FIG. 5B, that is, the four corners around the display unit 5 It is left in a state close to the positive display color. This is considered a problem from an aesthetic point of view,
In order to solve this problem as well, second and third examples of voltages applied to the peripheral electrodes in the first embodiment of the present invention will be described below.

FIGS. 10A and 10B illustrate the first embodiment of the present invention as described above.
11 shows a second example of the voltage applied to the peripheral electrode in the embodiment of FIG.

That is, in the example of FIGS. 10A and 10B, the peripheral row electrodes 21 and 23 have the signal electrodes 12 ₁ , 12 ₂ ,.
DC components of the voltage applied to 12 _j ... 12 _n , that is, 15 V are applied, and the scanning electrodes 22 ₁ , 22 are applied to the peripheral column electrodes 11 and 13.
₂ ,... 22 _i ... 22 _n are applied with a voltage having the same DC component and an amplitude of ± 3 V.

When the voltage of the first FIG. 10A and the 10B view is applied to the peripheral electrode, the scan electrode _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes
Assuming that the voltages having the waveforms shown in FIGS. 7B and 7A are applied to 12 ₁ , 12 ₂ ,... 12 _i, 12 _n , the voltage applied to the liquid crystal material in the region E of FIG. The result is as shown in FIG. 11A. That is, in the region of E, ± 13V to 15V
AC voltage having an amplitude of Since this voltage is equal to or higher than the above-described threshold voltage of 2.5 V, the transmittance of the region E in the configuration of FIG. 5B is significantly increased, and this portion looks white.

Also, when the peripheral electrode voltage of the first FIG. 10A and the 10B view is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and 7A described above
Assuming that the voltage having the waveform shown in the figure is applied, the voltage applied to the liquid crystal material in the region F of the structure shown in FIG. 5B is as shown in FIG. 11B. That is, in the area of F, ± 10
An AC voltage having an amplitude of V to 18 V is applied. Since this voltage is also equal to or higher than the threshold voltage 2.5V, the fifth
The transmittance of the region F in the configuration shown in the figure is significantly increased, and this portion looks white.

Further, when the peripheral electrode voltage of the first FIG. 10A and the 10B view is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and 7A described above
Assuming that the voltage having the waveform shown in the figure is applied, the voltage applied to the liquid crystal material in the region G in the configuration shown in FIG. 5B is as shown in FIG. 11C. That is, at this time, an AC voltage having an amplitude of ± 3 V is applied to the G region. Therefore, since this voltage is also equal to or higher than the above-described threshold voltage of 2.5 V, the transmittance of the region G in the configuration of FIG. 5B also becomes remarkably high, and this portion also looks white. That is, by applying the voltages shown in FIGS. 10A and 10B to the peripheral electrodes, the aesthetic problem described above was solved.

FIGS. 12A and 12B illustrate a first embodiment of the present invention as described above.
13 shows a third example of the voltage applied to the peripheral electrode in the embodiment of FIG.

That is, in the example of FIGS. 12A and 12B, the peripheral column electrodes 11 and 13 are provided with the scanning electrodes 22 ₁ , 22 ₂ ,.
22 _j ... 22 _n have the same DC component as the voltage applied to
A voltage having an amplitude of 5V is applied. Also, the peripheral row electrode
21 and 23, signal electrodes 12 _1, 12 _2, has a ... 12 _i ... 12 voltage same DC component and applied to the _n, a voltage having an amplitude of ± 8V is applied.

When the voltage of the FIG. 12A and FIG. 12B is applied to the peripheral electrode, the scan electrode _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes
Assuming that the voltages having the waveforms shown in FIGS. 7B and 7A are applied to 12 ₁ , 12 ₂ ,... 12 _i, 12 _n , the voltage applied to the liquid crystal material in the region E of FIG. The result is as shown in FIG. 13A. That is, an AC voltage having an amplitude of ± 3 V to 7 V is applied to the region E. Since this voltage is equal to or higher than the above-described threshold voltage of 2.5 V, the transmittance of the region E in the configuration of FIG. 5B is significantly increased, and this portion looks white.

Also, when the peripheral electrode voltage of the FIG. 12A and FIG. 12B is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and 7A described above
Assuming that the voltage having the waveform shown in the figure is applied, the voltage applied to the liquid crystal material in the region F of the configuration shown in FIG. 5B is as shown in FIG. 13B. That is, ± 8 V
And an AC voltage having an amplitude of 20 V is applied. Since this voltage is also equal to or higher than the threshold voltage 2.5V, the fifth
The transmittance of the region F in the configuration shown in the figure is significantly increased, and this portion also looks white.

Further, when the peripheral electrode voltage of the FIG. 12A and FIG. 12B is applied, the scanning electrodes _{22 1, 22 2, ... 22} j ... 22 n and the signal electrodes _{12 1, 12 2, ... 12} i ... 12 n 7B and 7A described above
Assuming that the voltage having the waveform shown in the figure is applied, the voltage applied to the liquid crystal material in the region G in the configuration shown in FIG. 5B is as shown in FIG. 13C. That is, at this time, an AC voltage having an amplitude of ± 3 V is applied to the G region. Therefore, since this voltage is also equal to or higher than the above-described threshold voltage of 2.5 V, the transmittance of the region G in the configuration of FIG. 5B also becomes remarkably high, and this portion also looks white. That is, by applying the voltages shown in FIGS. 12A and 12B to the peripheral electrodes, the aesthetic problem described above was solved.

The first, second and third voltages applied to the peripheral electrodes
Examples As is apparent from, the peripheral row electrodes 21 and 23, have equal DC component and the DC component of the signal electrodes 12 _1, 12 _2, the voltage applied to ... 12 _n, the scanning electrodes 12 ₁ , 12 ₂ ,… 12 _n
The AC voltage whose effective value of the difference from the voltage applied at the time of non-selection is equal to or higher than a predetermined threshold value required for causing a sharp change in light transmittance in the liquid crystal cell to which these voltages are applied. When applied, a voltage is applied to a region E in FIG. 5B of the liquid crystal cell where the effective voltage is equal to or higher than a predetermined threshold value required to cause the above-mentioned steep change in light transmittance. Therefore, this area E becomes white.

Further, scanning electrodes 22 ₁ ,
22 _2, ... DC component of the voltage applied to 22 _n and have equal DC component, the scanning electrodes 22 _1, 22 _2, the effective value of the difference between the voltages applied during the non-selection ... 22 _n, By applying an AC voltage that is equal to or higher than a predetermined threshold value required to cause a sharp change in light transmittance in the liquid crystal cell to which the voltage is applied,
5B of the liquid crystal cell, a voltage at which the effective voltage is equal to or higher than a predetermined threshold value required for causing the above-mentioned steep change in light transmittance is applied. Therefore, this area F becomes white.

Further, the effective value of the difference between the voltage applied to the peripheral row electrodes 21 and 23 and the voltage applied to the peripheral column electrodes 11 and 13 causes a sharp change in the light transmittance. If the threshold voltage is higher than the predetermined threshold required for causing the liquid crystal cell, the effective voltage is also applied to the area G in FIG. The above voltages are applied. Therefore, this area G also becomes white.

As described above, as a first embodiment of the present invention, FIG.
As shown in Figure 3B, has been described a liquid crystal display device in which stacked liquid crystal cells of two layers, the above description, for example, in the configuration of Figures 3A and Figure 3B, the glass from the glass substrate 32 ₃ removing the structure to the substrate 32 ₄ 1
This is also true in a configuration including a liquid crystal cell having two layers. That is, also at this time, as shown in FIGS. 3A and 3B, the peripheral electrodes are formed, and FIGS. 8A and 8B, or
Figures 10A and 10B, or Figures 12A and 12B
By applying a voltage as shown in the figure, the visibility of the display at the end of the image display area can be improved.

FIG. 14 shows the configuration of an STN-type liquid crystal display device having a two-layer liquid crystal cell according to a second embodiment of the present invention.

In FIG. 14, reference numerals 30 ₁ and 30 ₂ denote layers of liquid crystal material, 31 ₁
And 31 ₂ are polarizing plates, 32 ₁ , 32 ₂ , 32 ₃ , 32 ₄ are glass substrates, 33
_1, 33 _2, 33 _3, 33 ₄ alignment film, 34 _1, 34 _2, 34 _3, 34 ₄ sealing material,
12 ₁ , 12 ₂ , 12 ₃ are transparent signal electrodes made of ITO electrodes and the like (actually, there are more), transparent scan electrodes made of ITO electrodes and the like as 22 _k (for example, k = 1 to 200), and 4 ₁ and 4
₂ is a peripheral area voltage applying means 4 for applying a voltage to an area of the liquid crystal cell for displaying an image, that is, a non-display section 6 around the display section 5 in accordance with the first embodiment of the present invention. These electrodes are also transparent electrodes made of ITO electrodes and the like.

Configuration of the above-mentioned liquid crystal display device except the peripheral electrodes 4 ₁ and 4 ₂ are near the column electrode 11 configured in the above-described first embodiment of the invention described above (Figures 3A and Figure 3B) and
13, and the same as those except for the peripheral row electrodes 21 and 23.

3A and 3B, the peripheral column electrodes
11 and 13 and the peripheral row electrodes 21 and 23 apply a voltage to a portion around a display section of a liquid crystal cell to which a voltage is applied by a scanning electrode and a signal electrode. In the configuration of FIG.
4 ₁ and 4 _2, a layer 30 ₁ of the first liquid crystal cell (liquid crystal material that receives the voltage applied by said scanning electrodes and signal electrodes, orientation films 3
3 _1, 33 _2, and the sealing material 34 _1, 34 second liquid crystal cell overlaid provided ₂ consists of) (a layer of liquid crystal material 30 _2, orientation films 3
3 ₃ , 3 _{3 4} and sealing material _{3 4 3} , _{3 4} )
Around the area 5 for displaying the image of the first liquid crystal cell,
It is provided so that a voltage is applied to a region overlapping with the region 6 not corresponding to the image.

The Figure 15, 1 in FIG. 14 near the electrode 4 ₁ and 4 ₂ of the structure
An example is shown as the peripheral electrode 41. In FIG. 15, the hatched portion is a portion of the peripheral electrode 41 having a shape corresponding to the area surrounding the area 5 for displaying the image of the first liquid crystal cell and the area 6 not corresponding to the image. It is. Incidentally, one of the peripheral electrodes 4 ₁ and 4 ₂ can be a solid electrode that covers the entire surface of the second liquid crystal cell.

The FIG. 16, another example of Figure 14 near the electrode 4 ₁ and 4 ₂ of the arrangement is shown as a peripheral electrode 42 _1, 42 _2, 42 _3. No. 16
In the figure, the peripheral electrodes 42 _1, 42 _2, 42 _3, parallel multiply provided in the boundary area 5 for displaying the image, have a form of a plurality of strip-shaped electrodes which can selectively applying a voltage to each doing.

Configuration of Figure 16 near the electrode 42 _1, 42 _2, 42 _3, 14 in the configuration of Figure, the layer of the layer 30 ₁ part of the liquid crystal material of the first liquid crystal cell and the liquid crystal material of the second liquid crystal cell 30 between ₂ parts 1
Glass substrate 32 ₂ and 32 ₃ is provided with a thickness of to 2 mm, if the obliquely viewed liquid crystal panel, the peripheral at the end of the first liquid crystal cell of the image display portion in the first liquid crystal cell because it can and the electrode 4 ₁ and 4 ₂ of the inner end portion is shifted is obtained by adapted to correct this.

FIG. 17 and FIG. 18 are similar to those to which the above-described first embodiment (first and second embodiments) of the present invention is applied.
The third embodiment of the present invention in which the above-described second embodiment of the present invention is applied to an STN type liquid crystal display device having a two-layer liquid crystal cell.
And a configuration of a fourth embodiment.

In any of FIG. 17 and FIG. 18, 30 ₃ and 30 ₄
Are liquid crystal substance layers, 31 ₃ and 31 ₄ are polarizing plates, 32 ₅ , 32 ₆ , 32 ₇ ,
32 ₈ glass substrate, 33 _5, 33 _6, 33 _7, 33 ₈ alignment film, 34 _5, 34 ₆
Is a sealing material, 12 ₁ , 12 ₂ , 12 ₃ , 12 ₄ are transparent signal electrodes (actually, more) composed of ITO electrodes and the like, and 22 _r is a transparent scanning electrode composed of ITO electrodes and the like (for example, r = 1 to 200).

17 in the configuration of view and FIG. 18, in the configuration of the second embodiment of the invention described above, is a polarizer 31 ₃ to correspond to the incident light polarization state setting unit 1 _1, the liquid crystal passes light polarized state selection it is a polarizer 31 ₄ to correspond to part 1 _2.

Then, as a characteristic configuration of the second aspect of the present invention, in the fourth embodiment shown in the third embodiment and FIG. 18 as indicated in FIG. 17, a layer of liquid crystal material 30 _4, a glass substrate 32 _7, 32 _8, the alignment film 33 _7, 33 _8, made from the sealing material 34 ₆ receives the voltage applied to the display image by the signal electrodes 12 _1, 12 _2, 12 _3, 12 ₄ and the scan electrodes 22 _r in the first liquid crystal cell, the thickness of the layer 30 ₄ of the liquid crystal material, said signal electrode 1
2 ₁ , 12 ₂ , 12 ₃ , 12 ₄ and the area to which a voltage for image display is applied by the scanning electrode 22 _r , that is, the display section 5 and the area around the display section 5, that is, the non-display section 6 In different ways.

In the third embodiment shown in FIG. 17, the non-display portion 6 a layer 3 of the liquid crystal material of the layer thickness 30 ₄ display unit 5 of the liquid crystal material
0 ₄ is smaller than the thickness, the non-display portion reduced in part transparent material 35 ₁ having a thickness of 6 and 35 ₂ (for example, Si
O ₂ ) is filled.

In the fourth embodiment shown in FIG. 18, and the layer 30 thickness of ₄ of the liquid crystal material for the non-display portion 6 is larger than the thickness of the layer 30 ₄ of the liquid crystal material of the display unit 5, the transparent substance 35 ₃ and 35 ₄ are charged to a small portion of the thickness of the display unit 5.

As described above, linearly polarized light incident through the polarizing plate 31 _3, when the voltage applied to the first liquid crystal cell is less than a predetermined threshold value, passes through the liquid crystal cell of the first Although it becomes a kind of elliptically polarized light, the elliptically polarized light returns to the original linearly polarized light again by passing through the second liquid crystal cell. Therefore, if the direction of linear polarization of light that can pass through the polarizer 31 ₄ to be perpendicular to the direction of the linearly polarized light, the voltage above applied light region is less than a predetermined threshold value The transmittance is small, that is, the display is black.

However, as in the non-display section 6 of the fourth embodiment shown in the third embodiment and FIG. 18 as indicated in FIG. 17, the layer 30 thickness of ₄ of the liquid crystal material of the first liquid crystal cell When configured to be different from the thickness of the layer 30 ₃ of the liquid crystal material of the second liquid crystal cell, the non-display section 6 of the layer 30 ₄ of the liquid crystal material of the liquid crystal cells of the first
Component elliptic polarized light that has passed through the region of, without returning to the linearly polarized light even after passing through the second liquid crystal cells having different thicknesses, since the state of elliptically polarized light, which can pass through the polarizing plate 31 ₄ Having. Therefore, by adjusting the thickness of a region of the first non-display section 6 of the layer 30 ₄ of the liquid crystal material of the liquid crystal cell suitably, the light transmittance of the non-display section 6, the display unit 5
Can be easily visually recognized even if the black display in the end region of is adjacent to the non-display portion 6 around the display portion 5.

FIG. 19 is an experimental value of the light transmittance in the non-display section 6 when the thickness of the liquid crystal layer in the non-display section 6 is different from the thickness of the liquid crystal layer in the display section 5 as described above. Is shown on the horizontal axis of the difference in thickness.

When the difference in the thickness of the liquid crystal layer between the display unit 5 and the non-display unit 6 is 0, the transmittance of light in the non-display unit 6 is 0, but when the difference in the thickness is 2 to 3 μm. Light transmittance is about
40%. When the thickness difference is 2 μm, the non-display portion 6
Appears white, and when the thickness difference is 3 μm, the non-display portion 6
Has been shown to appear yellow.

In order to improve the visibility of black display in the end region of the display unit 5, the difference in thickness is desirably 0.5 μm or more.

〔The invention's effect〕

ADVANTAGE OF THE INVENTION According to the liquid crystal display device of this invention, the visibility of the display of the edge part of the area | region where an image is displayed can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the principle of the first embodiment of the present invention, FIG. 2 is a diagram showing the principle of the first embodiment of the present invention, and FIGS. 3A and 3B are diagrams of the first embodiment of the present invention. FIGS. 4A and 4B are configuration diagrams of an upper substrate and a lower substrate in the first embodiment of the present invention, respectively. FIG. 5A is an upper substrate of FIG. 4A and a lower side of FIG. 4B. FIG. 5B is a partially enlarged view of FIG. 5A, and FIG. 6 is a diagram showing one of waveforms of voltages applied to signal electrodes and scanning electrodes in the first embodiment of the present invention. FIG. 7A is a diagram showing an example, FIG. 7A is a diagram showing an example of a waveform of a voltage applied to a signal electrode in the first embodiment of the present invention, and FIG. 7B is a scanning electrode in the first embodiment of the present invention. FIGS. 8A and 8B show an example of the waveform of the voltage applied to the first embodiment of the present invention. FIG. 9A, FIG. 9B and FIG. 9C show the applied voltage to the row and column electrodes and the applied voltage to the peripheral row electrodes, respectively, and FIG. 5B by the peripheral electrode voltage application in FIGS. 8A and 8B respectively. FIG. 10A and FIG. 10B are diagrams showing a voltage applied to the liquid crystal material in the regions E, F, and G of the non-display portion of FIG. FIG. 11A, FIG. 11B and FIG. 11C are diagrams showing an applied voltage to a peripheral row electrode and an applied voltage to a peripheral column electrode, respectively. FIG. 5B is a diagram showing the voltage applied to the liquid crystal material in the regions E, F, and G of the non-display portion. FIGS. 12A and 12B are third views of the peripheral electrode voltage application in the first embodiment of the present invention. FIG. 13A, FIG. 13B and FIG. 13B show the applied voltage to the peripheral row electrodes and the applied voltage to the peripheral column electrodes in the example of FIG. FIG. 13C is a diagram showing the voltage applied to the liquid crystal material in the regions E, F, and G of the non-display portion in FIG. 5B by the peripheral electrode voltage application in FIG. 12A and FIG. 12B, respectively. FIG. 15 is a diagram showing a first configuration example of the peripheral electrode of FIG. 14, and FIG. 16 is a diagram showing a second configuration example of the peripheral electrode of FIG. FIG. 17, FIG. 17 is a configuration diagram of a third embodiment of the present invention, FIG. 18 is a configuration diagram of a fourth embodiment of the present invention, FIG. 19 is a configuration of FIG. 17 and FIG. FIG. 20 is a view showing a difference in thickness of a liquid crystal material layer between a display diagram and a non-display portion in FIG. 20 and a transmittance of light in the non-display portion. FIG. 21 is a diagram schematically showing a configuration for applying a voltage, FIG. 21 is a plan view of a configuration of a conventional liquid crystal display device, and FIG. 22 shows a voltage-transmittance characteristic in a liquid crystal cell. , FIG. 23 is a diagram showing an example of a display at the boundary portion between the display view and the non-display portion in a conventional liquid crystal display device. [Explanation of Symbols] 1 ₁ ... Incident light polarization state setting unit 1 ₂ ... Liquid crystal passing light polarization state selection unit 2... Image display voltage applying means 3, 3 ′, 30.
Liquid crystal cell, 4 ... surrounding area voltage applying means, 5 ... display section, 6 ... non-display section, 10 ... upper substrate, 11, 13 ... peripheral column electrode, 12 ... signal electrode section, 12 ₁ , 12 ₂ , to 12 _n ... column electrodes (signal electrodes), 20 ... lower substrate, 21, 23 ... peripheral row electrodes, 22 ... scanning electrode parts, 22 ₁ , 22 ₂ , ... 22 _n ... rows Electrodes (scanning electrodes), 30 ₁ , 30 ₂ , 30 ₃ , 30 ₄ …… a layer of liquid crystal material, 31 ₁ , 3
1 ₂ , 31 ₃ , 31 ₄ ...... Polarizer, 32 ₁ , 32 ₂ , 32 ₃ , 32 ₄ , 32 ₅ , 32 ₆ , 32 ₇ ,
32 ₈ ...... Glass substrate, 33 ₁ , 33 ₂ , 33 ₃ , 33 ₄ , 33 ₅ , 33 ₆ , 33 ₇ , 33 ₈
… Is an alignment film, 34 ₁ , 34 ₂ , 34 ₃ , 34 ₄ , 34 ₅ , 34 ₆ …… sealing material, 35 ₁ , 35 ₂ , 35 ₃ , 35 ₄ … transparent material, 4 ₁ , 4 ₂ , 41: Peripheral electrodes, 42 ₁ , 42 ₂ , 42 ₃ ... Strip electrodes.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-26621 (JP, A) JP-A-63-247728 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G09G 3 / 18,3 / 36 G02F 1/133

Claims (5)

(57) [Claims] 1. A liquid crystal cell (30) having a layered structure, and a voltage is applied to one side of the liquid crystal cell (30) to a liquid crystal material in a region corresponding to a pixel in each column of a screen for displaying an image. a plurality of transparent column electrodes _{(12 1, 12 2, ...} 12 n) for comprising a, on the other side of the liquid crystal cell (30), a voltage to the liquid crystal material in a region corresponding to each row of pixels of the screen In a liquid crystal display device comprising a plurality of transparent row electrodes (22 ₁ , 22 ₂ ,... 22 _n ) for applying a voltage, the plurality of column electrodes (12 ₁ ) on one side of the liquid crystal cell (30) are provided. , 12 ₂ ,... 12 _n ) are provided adjacent to and adjacent to both sides of the row, and the plurality of row electrodes (22 ₁ ) on the other side of the liquid crystal cell (30) are provided. , 22 ₂ ,... 22 _n ) and adjacent row electrodes (21, 23) are provided adjacent to both sides of the column electrodes (12 ₁ , 12 ₂ ,... 12 _n ) and the row electrodes (22 ₁ , 2 _n ).
22 ₂ ,... 22 _n )
A voltage having an AC component having an effective value equal to or higher than a predetermined threshold value required for causing a sharp change in light transmittance in the liquid crystal cell (30), and the peripheral row electrode (21, 23) or the Peripheral column electrodes (11,1
Either one of 3), the row electrodes (22 _1, 22 _2, ... 22 _n) or the column electrodes (12 _1, 12 _2, ... substantially equal to the DC component of the voltage applied to 12 _n) A DC voltage is applied, and the peripheral row electrodes (21, 23) or the peripheral column electrodes (11, 1) are applied.
The other 3), said row electrodes _{(22 1, 22 2, ...} 22 n) or the column electrodes _{(12 1, 12 2, ...} 12 n) the DC component of the voltage applied to substantially equal DC component Having an AC component having an effective value equal to or greater than the predetermined threshold, and having the row electrode (22
_{1, 22 2, ... 22 n} ) and the column electrodes _{(12 1, 12 2, ...} 12 n) of the effective difference between the AC voltage to be applied to people of electrodes orthogonal to the other electrode A liquid crystal display device, wherein a voltage having a value equal to or higher than the predetermined threshold is applied. 2. A first liquid crystal cell (30 ₁ , 33 ₁ , 33 ₂ ,
34 ₁ , 34 ₂ ) and the first liquid crystal cell (30 ₁ , 33 ₁ , 33 ₂ , 34 ₁ , 34 ₂ )
And a layered second liquid crystal cell (30 ₂ , 33
_3, 33 _4, 34 _3, 34 ₄₎ and having a first liquid crystal cell (30 _1, 33 _1, 33 _2, 34 _1, one side of the 34 _2), a screen for displaying the pixel A plurality of transparent column electrodes (12 ₁ , 12 ₂ ,..., 12 _n ) for applying a voltage to the liquid crystal material in a region corresponding to the pixels in each column. A liquid crystal display device comprising a plurality of transparent row electrodes (22 ₁ , 22 ₂ ,... 22 _n ) for applying a voltage to a liquid crystal material in a region corresponding to a pixel, wherein the second liquid crystal cell (30 ₂ , 33 _3, 33 _4, 34 _3, in 34 _4), the periphery of the first liquid crystal cell (30 _1, 33 _1, 33 _2, 34 _1, 34 ₂₎ the image display area (5) , peripheral electrode for applying a voltage to the region to be overlaid on the region (6) which do not correspond to the image (4 _1, 4 _2, 41 _1, 42 _2, 42 ₃₎ is provided, the peripheral electrode (4 _1, 4 ₂ , 41, 42 ₁ , 42 ₂ , 42 ₃ )
Liquid crystal cell (30 _2, 33 _3, 33 _4, 34 _3, 34 ₄₎ applying an AC voltage having an effective value higher than a predetermined threshold required to cause an abrupt change in transmittance of light in Wherein the area (6) not corresponding to the image has substantially the same brightness as the background of the area (5) displaying the image. 3. A plurality of peripheral electrodes provided in parallel with a boundary of a region (5) for displaying the image, and strip electrodes (42 ₁ , 42 ₂ , 42 ₃ ) to which a voltage can be selectively applied. The liquid crystal display device according to claim 2, comprising: 4. A liquid crystal cell (3 ') containing a layered liquid crystal material.
An incident light polarization state setting unit (1 ₁ ) provided on one side of the liquid crystal cell (3 ') and setting the polarization state of light incident on the liquid crystal cell (3') to a predetermined state; A liquid crystal passing light polarization state selector (1 ₂ ) provided on the other side of the liquid crystal cell (3 ') and passing only a component of a predetermined polarization state out of the light passing through the liquid crystal cell (3'). A liquid crystal display device for displaying an image in a predetermined area (5) of the liquid crystal cell (3 '), wherein the liquid crystal cell (3') has a predetermined area (5) for displaying the image. The thickness of the layer of the liquid crystal material in
The difference between the thickness of the liquid crystal material layer in the area (6) surrounding the predetermined area (5) and the thickness of the liquid crystal material layer is set to about 2 μm so that the surrounding area (6) is displayed in white. Liquid crystal display device. 5. A liquid crystal cell (3 ') containing a layered liquid crystal substance.
An incident light polarization state setting unit (1 ₁ ) provided on one side of the liquid crystal cell (3 ') and setting the polarization state of light incident on the liquid crystal cell (3') to a predetermined state; A liquid crystal passing light polarization state selector (1 ₂ ) provided on the other side of the liquid crystal cell (3 ') and passing only a component of a predetermined polarization state out of the light passing through the liquid crystal cell (3'). A liquid crystal display device for displaying an image in a predetermined area (5) of the liquid crystal cell (3 '), wherein the liquid crystal cell (3') has a predetermined area (5) for displaying the image. The thickness of the layer of the liquid crystal material in
A difference between the thickness of the liquid crystal material layer in a region (6) surrounding the predetermined region (5) and the thickness of the liquid crystal material layer is set to about 3 μm so that the surrounding region (6) is displayed in yellow. Liquid crystal display device.