JP2001209053A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain quick response of a liquid crystal display device with a columnar spacer. SOLUTION: The columnar spacer is formed with a material of which the dielectric constant is smaller than that of the liquid crystal composition. By forming the columnar spacer SP on the electrode of the signal line DL, the load on the signal line DL is reduced so as to attain fast response.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a novel structure for maintaining a constant distance between a pair of substrates for sealing a liquid crystal composition.

[0002]

2. Description of the Related Art A liquid crystal display device has been widely used as a display device capable of displaying a high-definition color image for a notebook computer or a computer monitor.

In this type of liquid crystal display device, a liquid crystal composition (hereinafter, also simply referred to as a liquid crystal or a liquid crystal layer) is sandwiched between at least two substrates, at least one of which is made of transparent glass. A so-called liquid crystal panel configured as described above, and a type (simple matrix type liquid crystal display device) in which predetermined voltages are selectively turned on and off by selectively applying voltages to various electrodes for pixel formation formed on the substrate of the liquid crystal panel. The above-mentioned various types of electrodes and active elements for pixel selection are formed, and the active elements are selected to turn on and off predetermined pixels (active matrix liquid crystal display devices).

An active matrix type liquid crystal display device is
Typically, a thin film transistor (TFT) is used as an active element constituting the liquid crystal panel. 2. Description of the Related Art A liquid crystal display device including a liquid crystal panel using a thin film transistor is widely used as a monitor for a display terminal of an OA device or the like because it is thin and lightweight and has high image quality comparable to a cathode ray tube.

[0005] The display methods of this liquid crystal display device are roughly classified into the following two types based on the difference in the method of driving the liquid crystal panel.
One is that the liquid crystal composition is sandwiched between two substrates on each of which a transparent electrode is formed, and is operated at a voltage applied to the transparent electrode to modulate light transmitted through the transparent electrode and incident on the liquid crystal composition layer. Display method (so-called vertical electric field method or T
N method), and many of the products that are currently widely used adopt this method.

[0006] The other is to operate by an electric field formed substantially parallel to the substrate surface between two electrodes formed on the same substrate, and to make light incident on a layer of the liquid crystal composition from a gap between the two electrodes. The liquid crystal panel uses a liquid crystal panel of a type that modulates and displays an image, has a characteristic that a viewing angle is extremely wide, and is an extremely high image quality type as an active matrix type liquid crystal display device. The features of this method are described in, for example, Japanese Patent Publication No. 5-505247, Japanese Patent Publication No. 63-21907, and Japanese Patent Application Laid-Open No. 6-160878. Hereinafter, this type of liquid crystal display device is referred to as a horizontal electric field type liquid crystal display device.

The present invention relates to a vertical electric field type liquid crystal display device among the various types of liquid crystal display devices described above.

FIG. 14 is a schematic plan view for explaining the structure near one pixel of a liquid crystal panel of a conventional vertical electric field type liquid crystal display device. An active matrix substrate SUB1 which is one substrate of the liquid crystal panel is replaced by another substrate. FIG. 16 is a plan view seen through from a certain color filter substrate SUB2 (see FIG. 15) side;
The black matrix BM formed on the color filter substrate SUB2 is indicated by a boundary line. FIG. 15 corresponds to FIG.
FIG. 2 is a sectional view taken along line 1-1 ′ of FIG.

This liquid crystal display device has one substrate SUB1
A thin film transistor TFT and a gate signal line GL formed of an amorphous silicon semiconductor or a polycrystalline silicon semiconductor
Video signal line DL, storage electrode line STG forming a storage capacitor, insulating film PSV1, protective film PSV2, pixel electrode I
TO1, an alignment control layer, that is, an alignment film ORI1 is formed.

On the other substrate SUB2, a black matrix BM, a color filter FIL, an overcoat layer OC, a counter electrode ITO2, and an orientation film ORI2 are formed.

Then, a liquid crystal composition layer (hereinafter, also simply referred to as a liquid crystal layer) LC is sealed in a bonding gap between the one substrate SUB1 and the other substrate SUB2 to form a liquid crystal panel.

One substrate SUB1 and the other substrate SUB2
Polarizing plates POL1 and POL2 are provided on the respective outer surfaces.

The distance (thickness of the liquid crystal layer: cell gap) between the pair of substrates SUB1 and SUB2 is set to a predetermined value by dispersing spherical spacers (not shown) between the two substrates. Is common.

Japanese Patent Application Laid-Open No. Hei 9-73088 discloses a method in which a fixed spacer is formed on a color filter substrate instead of such a spherical spacer, or a conical spacer is fixedly formed on a substrate by laminating a color filter layer. It is disclosed in the gazette.

In Japanese Patent Application Laid-Open No. 9-73088,
When a spherical spacer is used, a display defect due to a decrease in contrast due to light leakage from the peripheral portion of the spacer and a non-uniform arrangement of the spacers in the process of dispersing the spacers on the substrate is said to occur. In order to prevent this, a conical spacer is fixedly formed on the substrate.

[0016]

The problem to be solved by the present invention is to reduce the load on the signal line DL of the liquid crystal display device and to prevent the image quality of the liquid crystal display device having high speed response, high definition and high brightness from deteriorating. That is.

The load on the signal wiring DL increases as the wiring resistance and the wiring capacitance increase. When the load on the signal line DL becomes heavy, it becomes difficult to transmit a desired signal waveform, and it becomes difficult to apply a desired voltage to the pixel electrode. As a result, desired image quality cannot be obtained.

Here, paying attention to the wiring capacitance of the signal wiring DL, the wiring capacitance is, as shown in FIG. 15, a capacitance C1 formed by the signal wiring DL and the pixel electrode ITO1,
Capacitance C formed by signal line DL and counter electrode ITO2
Determined by the sum of 2.

In the conventional liquid crystal display device, the distance between the signal line DL and the pixel electrode ITO1 is equal to the distance between the signal line DL and the counter electrode I1.
Generally, the capacitance C1 is larger than the capacitance C2 because the distance is considerably larger than the distance TO2 and the capacitance is inversely proportional to the distance between the electrodes.
Greater than.

However, in recent years, the distance between the pixel electrode and the counter electrode has tended to be shorter in order to increase the response speed of the liquid crystal display device. This is the response time rise time (τ
This is because r) and the degradation time (τd) are proportional to the square of the thickness (cell gap) of the liquid crystal layer (for example, see “Liquid Crystal Display Technology”, edited by Shoichi Matsumoto, published by Sangyo Tosho).

Therefore, it is advantageous to reduce the cell gap for high-speed response. In this case, however, the capacitance C2 increases and the load on the signal line DL increases. In addition, when the distance between the signal line DL and the pixel electrode ITO1 is increased to reduce the capacitance C1, the aperture ratio is reduced. In particular, in a high-definition liquid crystal display device, the backlight is used to compensate for the decrease in luminance due to the reduced aperture ratio. Etc., resulting in increased brightness of lighting devices,
This leads to an increase in power consumption.

It is an object of the present invention to provide a liquid crystal display device which solves the above-mentioned problems of the prior art and has a high-speed response, high definition, high luminance and reduced image quality deterioration.

[0023]

According to the present invention, there is provided a liquid crystal display device comprising: a columnar spacer disposed between a pair of substrates constituting a liquid crystal panel of a liquid crystal display; The feature is that it is smaller than that of.

Further, the present invention is characterized in that the arrangement of the columnar spacers is specified, or the relationship with the alignment direction of the alignment film is specified.

A typical configuration of the present invention is described in the following (1) to (7). That is, (1): a pair of substrates, at least one of which is transparent, at least two or more types of color filters having different colors for color display formed on one of the pair of substrates, and interposed between the color filters. Black matrix,
Electrodes formed adjacent to the pixels on the pair of substrates,
A liquid crystal panel having a layer of a liquid crystal composition having dielectric anisotropy between the pair of substrates and an alignment control layer for arranging the molecular arrangement of the layer of the liquid crystal composition in a predetermined direction;
A driving unit for applying a driving voltage for display to the electrode, a columnar spacer having a relative dielectric constant smaller than that of the liquid crystal composition on the electrode in a region hidden by a black matrix. Formed.

Generally, when the relative dielectric constant (ε) is used as a coefficient, the magnitude of the capacitance (C) is proportional to the area (S) of the electrode constituting the capacitance and inversely proportional to the distance (d) between both electrodes ( C =
ε × S / d). Therefore, by setting the relative dielectric constant of the columnar spacer to ε _SP , the relative dielectric constant of the liquid crystal layer to ε _LC, and the relationship of ε _SP <ε _LC , the capacitance of the portion where the columnar spacer is a dielectric is It can be made relatively small with respect to the portion that has been described.

This becomes more conspicuous as the cell gap of the liquid crystal panel becomes smaller. As a result, the load on the electrodes is particularly reduced.

This is particularly noticeable in the electrodes constituting the video signal lines for supplying high-frequency video signals, and a high-speed response is achieved. Note that the same effect can be obtained for the scanning signal line as the scanning signal frequency increases, and the same applies to the case where the columnar spacer is formed on the electrode constituting the scanning signal line.

(2): One or more columnar spacers in (1) are arranged for each pixel along the direction in which the electrodes extend.

(3): One of the columnar spacers in (1) is arranged for every plural pixels along the extending direction of the electrode group.

(4): One of the columnar spacers in (1) is arranged for each of the electrodes in the effective area of the liquid crystal panel over the entire length in the extending direction.

The columnar spacer is generally formed adjacent to one pixel in parallel on an electrode such as a video signal line. The columnar spacer extends along the entire area of one side of one pixel. Or one short columnar spacer
A plurality of pixels can be arranged on one side of the pixel, or they can be continuously arranged over the sides of the plurality of pixels.

This arrangement can be selected according to the required specifications such as the size of the cell gap of the liquid crystal panel, the processability of forming the columnar spacer, the rubbing processability, and the like. Even with this configuration, the same effect as the above (1) can be obtained.

(5): The columnar spacer in (1) is arranged over the entire length of the effective area of the liquid crystal panel in the direction in which the electrodes extend, and the liquid crystal composition injected into one or a plurality of positions is distributed. A gap was formed to make the gap.

(6): The longitudinal direction or arrangement direction of the columnar spacers in (1) to (5) was arranged in parallel with the injection direction of the liquid crystal composition.

In the above configuration, the photomask for forming the columnar spacer can be easily formed, and the cell gap can be set firmly. At this time, it is desirable to form the gap so that the liquid crystal injected between the pair of substrates is uniformly filled in the display area as in (5). Preferably, if the columnar spacers are arranged in parallel to the liquid crystal injection direction as in (6), the flow of the injected liquid crystal can be made smoother and the liquid crystal can be uniformly filled.

(7): The columnar spacer in (1) to (6) is formed on one of the pair of substrates, and the alignment direction of the alignment film provided on the substrate side on which the columnar spacer is formed. Is parallel or substantially parallel to the longitudinal direction or the arrangement direction of the columnar spacers.

Since the columnar spacers need only be disposed between a pair of substrates, they may be formed on either side of the pair of substrates as shown in FIG. It is.

In the above configuration, the cell gap is regulated only by the columnar spacers. However, although not specifically shown and described, the height of the columnar spacers is set lower than a predetermined cell gap. The known spherical beads used for setting the cell gap are sprayed so that the flow of the injected liquid crystal composition is not obstructed by the columnar spacers, and the cell gap may be mainly performed by the spherical beads. .

In a preferred configuration of the present invention, a columnar spacer is formed on a video signal line having a high signal frequency in an electrode group formed on an active matrix substrate which is one of the substrates. Then, the alignment film is formed parallel or almost parallel to the alignment processing direction (alignment direction) and the arrangement direction of the columnar spacers (longitudinal direction) for imparting alignment controllability by rubbing or optical alignment to the alignment film material formed thereon. By doing so, it is possible to reduce the occurrence of poor alignment near the downstream of the columnar spacer in the alignment direction.

By adopting the structure of the present invention, it is possible to obtain a liquid crystal display device in which the load on the electrodes constituting the signal wiring and the like is reduced, and high-speed response, high definition, and high brightness, and image quality deterioration are suppressed.

It should be noted that the present invention is not limited to the above configuration and the configurations disclosed in the embodiments described later, and it is needless to say that various modifications can be made without departing from the technical idea of the present invention. No.

[0043]

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

FIG. 1 shows the vicinity of one pixel formed on an active matrix substrate which is one substrate of a liquid crystal panel constituting a vertical electric field type active matrix type liquid crystal display device which is a first embodiment of the liquid crystal display device according to the present invention. Is a plan view of a main part schematically illustrating the configuration of FIG. 1, showing a state seen through from a color filter substrate side, which is the other substrate, and BM indicates a black matrix by a boundary line.

FIG. 2 is a sectional view taken along line 1-1 'in FIG. In FIGS. 1 and 2, the same reference numerals as those in FIGS. 14 and 15 correspond to the same functional portions, and are the same as the respective drawings except for the columnar spacer.

That is, in FIG. 1, DL is a video signal line (drain line) of the electrode group formed on the active matrix substrate, GL is the same scanning signal line (gate line), T
FT is a thin film transistor (TFT), AS is an amorphous silicon or polycrystalline silicon layer constituting the thin film transistor, ITO1 is a pixel electrode, and STG is a storage electrode line forming a storage capacitor.

In FIG. 2, an insulating film PSV1, a protective film PSV2, a pixel electrode ITO1, an alignment control layer, that is, an alignment film ORI1, are formed on an active matrix substrate SUB1.
Columnar spacers SP are formed.

On the other substrate SUB2, a black matrix BM, a color filter FIL, an overcoat layer OC, a counter electrode ITO2, and an orientation film ORI2 are formed.

Then, the active matrix substrate SUB
A liquid crystal panel is formed by enclosing a liquid crystal composition layer (liquid crystal layer) LC in a bonding gap between the color filter substrate 1 and the color filter substrate SUB2.

Note that one substrate SUB1 and the other substrate S
Polarizing plates POL1, POL are provided on each outer surface of UB2.
2 are installed.

In this embodiment, the columnar spacers SP are formed on the active matrix substrate SUB1. The columnar spacer SP is formed of a resin layer, and has a relative dielectric constant smaller than that of the liquid crystal LC.

Since the relative permittivity of the columnar spacer SP is smaller than that of the liquid crystal LC, the capacitance C2 of the signal line DL and the pixel electrode ITO1 described with reference to FIG. 15 can be reduced. As a result, the load on the signal wiring DL can be reduced.

As a constituent material of the columnar spacer SP, a photosensitive resin resist is used. Commercially available photosensitive resin resists are primarily acrylic based. The relative permittivity of the acrylic resin is about 2.5 to 4.0 (from the Society of Materials Science of Japan, Material Science and Material Engineering, by Shigeharu Onoki, “Polymer Material Chemistry”).

On the other hand, nematic liquid crystals include azomethine compounds (Schiff chlorine compounds), azoxy compounds, cyanobiphenyls, benzoic acid phenyl esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexane, cyano-substituted phenylpyrimidine, alkoxy-substituted phenylpyrimidine, Phenyldioxane type and the like can be mentioned.

When the relative permittivity in the major axis direction of the liquid crystal molecules is represented by εL and the relative permittivity in the minor axis direction is represented by εS, among the above materials, an azomethine compound (Schiff chlorine compound) is regarded as a dielectric anisotropy Δε. Is negative and the relative dielectric constant εL in the major axis direction of the liquid crystal molecule.
= 4.75, relative dielectric constant εS in the minor axis direction of liquid crystal molecules = 5.3
8, those with positive Δε, εL = 26.0 and εS = 7.6 are known. As an azoxy compound, Δε is negative and εL
= 5.62, εS = 5.73, Δε is positive and εL = 4.1
7, those with εS = 3.98 are known. As cyanobiphenyls, those having a positive Δε, εL = 17 and εS = 6 are known. As benzoic acid phenyl ester type, Δ
It is known that ε is positive, εL = 5.9 and εS = 5.8. As cyanophenylcyclohexane, Δε is positive and εL = 15.2, εS = 5.1 or εL = 15.0.
0 and εS = 4.7 are known. As a phenyldioxane system, Δε is positive and εL = 23.87, εS =
9.45 are known (JSPS 14th)
2 Committee, “Liquid Crystal Device Handbook”).

As described above, the relative permittivity of the acrylic-based photosensitive resin resist is about 2.5 to 4.0, which is higher than the relative permittivity of a generally used liquid crystal (about 4 to 26). small.

According to the present embodiment, it is possible to obtain a liquid crystal display device in which the load on the signal wiring is reduced, high-speed response, high definition, high luminance, and image quality deterioration are suppressed.

FIG. 3 is a sectional view similar to FIG. 2 illustrating a second embodiment of the liquid crystal display device according to the present invention. This embodiment is the same as the first embodiment except that the columnar spacer SP is formed on the color filter substrate SUB2 side. By forming the columnar spacer SP on the color filter substrate SUB2 at the position of the video signal line DL formed on the active matrix substrate SUB1, the same effect as in the first embodiment can be obtained.

In FIGS. 1 to 3, the columnar spacer SP
In the vertical direction of the pixel (pixel electrode ITO1
, The length of the columnar spacer SP is not limited to this, and the columnar spacer SP may be formed longer to extend over a plurality of pixels, May be a shape other than the illustrated one, for example, a circle, an ellipse, a rhombus, or any other irregular shape. Since these need not be particularly illustrated and described, detailed description using the drawings is omitted. Hereinafter, representative examples of the embodiments that realize these will be described.

FIG. 4 is a sectional view similar to FIG. 1 illustrating a third embodiment of the liquid crystal display device according to the present invention. In the present embodiment, the columnar spacers SP are quadrangular shorter than those in FIG. 1, and a plurality of such spacers are arranged on the video signal line DL. According to the present embodiment, the same effects as those of the first embodiment can be obtained.

FIG. 5 is a schematic view for explaining an example of arrangement of columnar spacers for explaining a fourth embodiment of the liquid crystal display device according to the present invention. In the figure, SL indicates a seal surrounding the effective display area of the liquid crystal panel, INJ indicates a liquid crystal injection port formed in a part of the seal SL, A indicates a liquid crystal injection direction, and B indicates a liquid crystal injection path.

In this embodiment, the columnar spacer is formed so as to extend continuously along the extension direction of the video signal line DL in the display area of the liquid crystal panel. The extending direction of the columnar spacer SP is parallel to the liquid crystal injection direction A from the liquid crystal injection port INJ of the liquid crystal panel.

There is a gap at the end of the columnar spacer SP so that liquid crystal can flow. This gap is desirably placed outside the effective display area. In the figure, as shown by an arrow A, the liquid crystal injected from the inlet INJ flows as shown by an arrow B and fills between the pair of substrates of the liquid crystal panel.

In this embodiment, since the total area of the columnar spacers SP in the display area can be increased, a more uniform cell gap can be obtained.

FIG. 6 is a schematic diagram for explaining an example of the arrangement of columnar spacers for explaining a fifth embodiment of the liquid crystal display device according to the present invention, and the same reference numerals as those in FIG. 5 correspond to the same functional portions. In this embodiment, the columnar spacers SP of the embodiment described with reference to FIG. 5 are divided regularly or irregularly in the extending direction to form liquid crystal passages, and the number of liquid crystal passages B to be injected is increased. It is intended to enable smooth liquid crystal injection and to form a more uniform liquid crystal layer.

The portion where the columnar spacer SP is divided is preferably the portion of the scanning signal line GL, but may be another portion. Further, as shown in the figure, by setting the division length of the columnar spacer SP to be irregular, it is assumed that there is some light leakage assuming that the divisional portion of the columnar spacer SP is a portion adjacent to the pixel. Is also averaged, and the occurrence of moire can be suppressed.

In this embodiment, as in the fourth embodiment, the total area of the columnar spacers SP in the display region can be increased, so that a more uniform cell gap can be obtained and the flow of the injected liquid crystal can be made smoother. A uniform liquid crystal layer can be formed.

By adopting the structure of each embodiment of the present invention described above, the same high-speed response as in the above-described embodiment can be obtained, the load on the signal wiring can be reduced, and the high-speed response, high definition, high brightness, and high image quality can be obtained. A liquid crystal display device in which deterioration is suppressed can be obtained.

Next, the outline of the manufacturing process of the columnar spacer of each embodiment of the present invention will be described.

FIG. 7 is a schematic process chart for explaining a method of manufacturing a columnar spacer in a liquid crystal display device according to the present invention.
First, an active matrix substrate or a color filter substrate is manufactured by a known method until the alignment film material is formed.

A photosensitive resin is applied to this substrate (active matrix substrate or color filter substrate) (S
-1).

Ultraviolet rays are irradiated through an exposure mask having a pattern of columnar spacers to perform exposure (S-2). This photosensitive resin may be either a negative type (a resin in which a portion irradiated with ultraviolet rays is cured) or a positive type (a resin in which a portion irradiated with ultraviolet rays is removed by development).

After the exposure, the photosensitive resin other than the columnar spacer portion is removed in the developing step, and the resultant is baked) (S-3).

Thereafter, an alignment film material is applied and baked (S-4) to form an alignment film having a liquid crystal alignment control ability (S-5).

The substrate having the columnar spacers formed in this manner is passed to a subsequent substrate bonding step and a liquid crystal injection step to complete a liquid crystal panel.

In the rubbing treatment for imparting the liquid crystal alignment control ability to the alignment film material, there may be a case where a rubbing defect occurs due to the presence of the columnar spacer.

In general, the rubbing treatment is a work of rubbing the surface of the alignment film material with a rubbing cloth in a certain direction. At the time of this rubbing treatment, the resistance of the bristle of the rubbing cloth received from the columnar spacer makes it difficult for the region of the columnar spacer on the rubbing downstream side to be sufficiently rubbed, and insufficient rubbing may cause poor alignment.

FIG. 8 is a schematic diagram for explaining an example of the relationship between the columnar spacer and the rubbing direction (orientation direction) of the alignment film material in the present invention. In this example, the rubbing direction is determined in parallel with the extending direction (longitudinal direction, arrangement direction) of the columnar spacers SP.

At this time, a rubbing-deficient region occurs near the rubbing downstream of the columnar spacer SP. However, the rubbing-deficient region does not extend into the pixel opening (indicated by the black matrix BM boundary line of the pixel electrode ITO) and is on the scanning signal line GL in the figure. As a result, display quality due to poor orientation does not occur.

FIG. 9 is a schematic diagram for explaining another example of the relationship between the columnar spacer and the rubbing direction of the alignment film material in the present invention. In this example, the rubbing direction is determined at a slight angle with the extending direction (longitudinal direction, arrangement direction) of the columnar spacers SP.

At this time, similarly to the above, the columnar spacer SP
A rubbing-deficient region occurs near the rubbing downstream of the rubbing. However, the insufficient rubbing region hardly covers the pixel opening. As a result, display quality due to poor orientation is unlikely to occur.

In the above description, the case where the liquid crystal alignment control ability is imparted by the rubbing treatment has been described. However, the same applies to the case where the liquid crystal alignment control ability is imparted by the known light alignment treatment.
By setting the irradiation angle of the polarized light to be parallel or substantially parallel to the extending direction of the columnar spacer SP, the polarized columnar spacer S
Insufficient liquid crystal alignment controllability due to the shadow caused by P can be avoided. In the photo-alignment treatment, a polymer material whose molecular bond changes by light irradiation is used as an alignment film material, and a predetermined polarization is applied to the alignment film material applied to the substrate at a predetermined angle to control the alignment of the liquid crystal. This is a method of giving the ability.

The alignment film surfaces of the pair of substrates manufactured as described above are opposed to each other, and the periphery thereof is surrounded by a liquid crystal sealing opening INJ.
With the seal (adhesive) SL left behind (see FIGS. 5 and 6), a liquid crystal composition is injected between the substrates, and a liquid crystal filling port INJ
Is sealed with a sealing material. Thereafter, the distance between the two substrates is regulated by a columnar spacer (or a spherical spacer if the spherical spacer is also dispersed) by pressing to obtain a liquid crystal display device having a predetermined cell gap.

Next, the driving means of the liquid crystal display device to which the present invention is applied and specific examples of products will be described.

FIG. 10 is a schematic explanatory view of the driving means of the liquid crystal display device according to the present invention. A liquid crystal panel of a horizontal electric field type constituting a liquid crystal display device has an image display section constituted by a set of a plurality of pixels arranged in a matrix, and each pixel is a backlight (not shown) arranged at the back of the liquid crystal display device. It is configured to be able to independently control the modulation of transmitted light.

On the active matrix substrate (SUB1), which is one of the components of the liquid crystal display substrate, the active pixel region AR extends in the x direction (row direction) and the y direction (column direction).
The scanning signal line GL and the counter voltage signal line CL, which are electrodes arranged in parallel, are extended in the y direction while being insulated from each other, and the video signal lines DL, which are electrodes arranged in parallel in the x direction, are formed.

Here, a unit pixel (one pixel) is formed in a rectangular area surrounded by each of the scanning signal line GL, the counter voltage signal line CL, and the video signal line DL.

The liquid crystal display device includes a vertical scanning circuit V and a video signal driving circuit H as external circuits, and the vertical scanning circuit V sequentially supplies a scanning signal (voltage) to each of the scanning signal lines GL. The video signal drive circuit H supplies a video signal (voltage) to the video signal line DL in accordance with the timing.

The vertical scanning circuit V and the video signal driving circuit H are supplied with power from the liquid crystal driving power supply circuit 3 and input image information from the CPU 1 after being divided into display data and control signals by the controller 2. It is supposed to be.

FIG. 11 is an explanatory diagram of an example of a driving waveform of the liquid crystal display device according to the present invention. In the figure, the counter voltage applied to the counter electrode is a binary AC rectangular wave of VCH and VCL, and the scanning signals VG (i-1) and VG
The non-selection voltage of (i) is set to VCH and VCL every scanning period.
Is changed in two values. The amplitude width of the counter voltage and the amplitude value of the non-selection voltage are the same.

The video signal voltage applied to the pixel electrode is a voltage obtained by subtracting half the amplitude of the counter voltage from the voltage to be applied to the liquid crystal layer.

The counter voltage may be DC, but by converting it to AC, the maximum amplitude of the video signal voltage can be reduced, and a video signal drive circuit (signal side driver) having a low withstand voltage can be used.

FIG. 12 is an exploded perspective view for explaining the entire structure of the liquid crystal display device according to the present invention. The liquid crystal display device (hereinafter, a liquid crystal panel formed by bonding a pair of substrates SUB1 and SUB2, a driving means, a backlight, (A liquid crystal display module integrating other components: MDL)
This is to explain the specific structure of the above.

SHD is a shield case (also called a metal frame) made of a metal plate, WD is a display window, INS1
3 to 3 are insulating sheets, PCBs 1 to 3 are circuit boards constituting driving means (PCB 1 is a drain side circuit board: a circuit board for driving a video signal line, PCB 2 is a gate side circuit board, PCB
3 is an interface circuit board), JN1 to 3 are joiners for electrically connecting the circuit boards PCB1 to PCB3, TC
P1 and TCP2 are tape carrier packages, PNL is a liquid crystal panel, GC is a rubber cushion, ILS is a light shielding spacer, PRS is a prism sheet, SPS is a diffusion sheet,
GLB is a light guide plate, RFS is a reflection sheet, MCA is a lower case (mold frame) formed by integral molding, MO is an MCA opening, LP is a fluorescent tube, LPC is a lamp cable, and GB supports a fluorescent tube LP. A rubber bush, BAT is a double-sided adhesive tape, BL is a backlight made of a fluorescent tube, a light guide plate, or the like, and a liquid crystal display module MDL is assembled by stacking diffusion plate members in the arrangement shown.

The liquid crystal display module MDL has two kinds of storage / holding members of a lower case MCA and a shield case SHD, and includes insulating sheets INS1 to 3 and circuit boards PCB1 to PCB1.
3. A metal shield case SHD in which a liquid crystal panel PNL is stored and fixed, and a lower case MCA in which a backlight BL including a fluorescent tube LP, a light guide plate GLB, a prism sheet PRS, and the like are stored are combined.

An integrated circuit chip for driving each pixel of the liquid crystal panel PNL is mounted on the video signal line driving circuit board PCB1, and an interface circuit board PCB3
Is mounted with an integrated circuit chip that receives a video signal from an external host, receives a control signal such as a timing signal, and a timing converter TCON that processes timing to generate a clock signal.

The clock signal generated by the timing converter is integrated on the video signal line driving circuit board PCB1 via the clock signal line CLL laid on the interface circuit board PCB3 and the video signal line driving circuit board PCB1. Supplied to the circuit chip.

The interface circuit board PCB3 and the video signal line driving circuit board PCB1 are multilayer wiring boards, and the clock signal line CLL is the interface circuit board PCB3 and the video signal line driving circuit board PC
It is formed as an inner wiring of B1.

The liquid crystal panel PNL has a drain-side circuit board PCB1, a gate-side circuit board PCB2, and an interface circuit board PCB3 for driving TFTs.
Are connected by tape carrier packages TCP1 and TCP2, and the circuit boards are connected by joiners JN1, JN2, JN3.

The liquid crystal panel PNL is the active matrix type liquid crystal display device according to the present invention described above, and includes the columnar spacer described in the above embodiment in order to maintain the distance between the pair of substrates at a predetermined value.

FIG. 13 is a perspective view of a notebook computer as an example of an electronic device on which the liquid crystal display device according to the present invention is mounted.

The notebook computer (portable personal computer) includes a keyboard section (main body section) and a display section connected to the keyboard section by a hinge. Keyboard and host (host computer), CP
U and other signal generation functions, and the display unit has a liquid crystal panel P
NL, and drive circuit boards PCB1 and PCB
2, PCB3 with control chip TCON,
In addition, an inverter power supply board serving as a backlight power supply is mounted.

The liquid crystal display module described with reference to FIG. 12 in which the liquid crystal display panel PNL, the various circuit boards PCB1, PCB2, PCB3, the inverter power supply board, and the backlight are integrated is mounted.

[0104]

As described above, according to the present invention,
The relative dielectric constant of the columnar spacer arranged so as to cover the area between the video signal line and the counter electrode is smaller than that of the liquid crystal composition, so that the load on the electrode serving as the signal wiring can be reduced, and high-speed response and high response can be achieved. A liquid crystal display device with high definition and high luminance and preventing image quality deterioration can be obtained.

Further, by disposing the columnar spacers of the present invention, the cell gap can be made uniform, and the liquid crystal can be easily distributed at the time of injecting the liquid crystal.

Furthermore, it is possible to avoid poor alignment at the pixel openings when giving the liquid crystal alignment control ability to the alignment film material formed on the columnar spacers, and to achieve high quality image display with uniform brightness on the display screen. Can be obtained.

[Brief description of the drawings]

FIG. 1 shows a configuration around one pixel formed on an active matrix substrate which is one substrate of a liquid crystal panel constituting a vertical electric field type active matrix type liquid crystal display device which is a first embodiment of a liquid crystal display device according to the present invention. It is a principal part top view which illustrates typically.

FIG. 2 is a cross-sectional view taken along line 1-1 'of FIG.

FIG. 3 is a sectional view similar to FIG. 2, illustrating a second embodiment of the liquid crystal display device according to the present invention.

FIG. 4 is a sectional view similar to FIG. 1, illustrating a third embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a schematic diagram for explaining an example of arrangement of columnar spacers for explaining a fourth embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a schematic diagram for explaining an example of the arrangement of columnar spacers for explaining a fifth embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a schematic process diagram illustrating a method for manufacturing a columnar spacer in a liquid crystal display device according to the present invention.

FIG. 8 is a schematic diagram illustrating an example of a relationship between a columnar spacer and a rubbing direction (orientation direction) of an alignment film material according to the present invention.

FIG. 9 is a schematic diagram illustrating another example of the relationship between the columnar spacer and the rubbing direction of the alignment film material in the present invention.

FIG. 10 is a schematic explanatory view of a driving means of the liquid crystal display device according to the present invention.

FIG. 11 is an explanatory diagram of an example of a driving waveform of the liquid crystal display device according to the present invention.

FIG. 12 is an exploded perspective view illustrating the overall configuration of the liquid crystal display device according to the present invention.

FIG. 13 is a perspective view of a notebook computer as an example of an electronic device on which the liquid crystal display device according to the present invention is mounted.

FIG. 14 is a schematic plan view illustrating a configuration near one pixel of a liquid crystal panel of a conventional vertical electric field type liquid crystal display device.

FIG. 15 is a sectional view taken along line 1-1 'of FIG.

[Explanation of symbols]

DL Video signal line CL Counter voltage signal line ITO1 Pixel electrode STG Storage electrode line GL Scan signal line BM Black matrix (indicated by the boundary of the opening of the pixel section) TFT Thin film transistor SP Columnar spacer ORI1, ORI2 Alignment film OC Overcoat layer FIL Color filter LC Layer of liquid crystal (liquid crystal composition) PSV1 Insulating film PSV2 Protecting film ITO2 Counter electrode POL1, POL2 Polarizing plate SUB1, SUB2 Substrate.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shigeru Matsuyama 3300 Hayano, Mobara-shi, Chiba F-term in Display Group, Hitachi, Ltd. (reference) 2H089 LA09 LA16 LA18 LA20 LA22 MA04X NA14 NA24 PA03 QA14 QA16 RA04 SA16 SA19 TA04 TA07 TA09 TA12 TA13 2H090 HC05 JA03 JC03 KA04 LA02 LA04 LA15 MA06 MB01

Claims (7)

[Claims] 1. A pair of substrates, at least one of which is transparent, at least two or more kinds of color filters having different colors for color display formed on one of the pair of substrates, and interposed between the color filters. A black matrix, an electrode formed adjacent to the pixel on the pair of substrates, a layer of a liquid crystal composition having dielectric anisotropy between the pair of substrates, and a molecular arrangement of the layer of the liquid crystal composition. A liquid crystal panel having an alignment control layer for arranging the electrodes in a predetermined direction; and a driving unit for applying a driving voltage for display to the electrodes. To
A liquid crystal display device comprising a columnar spacer having a relative dielectric constant smaller than that of the liquid crystal composition. 2. The liquid crystal display device according to claim 1, wherein one or more columnar spacers are arranged for each pixel along the direction in which the electrodes extend. 3. The liquid crystal display device according to claim 1, wherein one of said columnar spacers is arranged for each of a plurality of pixels along an extending direction of said electrode group. 4. The liquid crystal display device according to claim 1, wherein one of said columnar spacers is arranged for each of said electrodes in an effective region of said liquid crystal panel over the entire length in the extending direction thereof. 5. The columnar spacer is disposed over the entire length of the effective area of the liquid crystal panel in the direction in which the electrodes extend, and a gap is formed for flowing a liquid crystal composition injected at one or more locations. The liquid crystal display device according to claim 1, wherein: 6. The liquid crystal display device according to claim 1, wherein the longitudinal direction or the arrangement direction of the columnar spacers is arranged in parallel with the injection direction of the liquid crystal composition. 7. The columnar spacer is formed on one of the pair of substrates, and the alignment direction of an alignment film provided on the substrate side on which the columnar spacer is formed is changed in the longitudinal direction or the arrangement of the columnar spacer. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is parallel or substantially parallel to a direction.