JP5907810B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a display device, and more particularly to an IPS liquid crystal display device having wall electrodes that have excellent viewing angle characteristics and can realize a high-definition screen.

  A liquid crystal display panel used for a liquid crystal display device includes a TFT substrate in which pixels having pixel electrodes and thin film transistors (TFTs) are formed in a matrix, and a location corresponding to the pixel electrode of the TFT substrate facing the TFT substrate. A counter substrate on which a color filter or the like is formed is disposed, and a liquid crystal is sandwiched between the TFT substrate and the counter substrate. An image is formed by controlling the light transmittance of the liquid crystal molecules for each pixel.

  Since liquid crystal display devices are flat and lightweight, they are used in various fields. Small liquid crystal display devices are widely used for mobile phones, DSCs (Digital Still Cameras), and the like. A viewing angle characteristic is a problem in a liquid crystal display device. The viewing angle characteristic is a phenomenon in which luminance changes or chromaticity changes when the screen is viewed from the front and when viewed from an oblique direction. The viewing angle characteristic is excellent in an IPS (In Plane Switching) system in which liquid crystal molecules are operated by a horizontal electric field.

  Even in the IPS system, when the pixel size is reduced on a high-definition screen, the transmittance becomes a problem, and the screen brightness becomes a problem. On the other hand, a wall electrode IPS-LCD (In-Plane-Swiching-Liquid Crystal Display) that applies an electric field to the liquid crystal layer using an electrode formed on the wall surface of the wall structure protruding into the liquid crystal layer uses a planar electrode. Since a more parallel electric field can be applied to the liquid crystal layer as compared with the conventional IPS-LCD, higher transmittance can be realized.

  Note that “Patent Document 1” describes a columnar spacer that is optimized for an IPS system from the viewpoint of reducing parasitic capacitance in a liquid crystal display device. In addition, “Patent Document 2” describes a configuration in which the wiring is covered with a wall structure and a common electrode is formed thereon in order to suppress the influence of the wiring potential in the IPS system. However, “Patent Document 2” does not describe the detailed configuration of the wall structure.

JP 2000-199904 A JP-A-9-258265

  Since the wall structure in the wall electrode type IPS is arranged under the black matrix at the pixel boundary, even if the pixel width is reduced due to high definition, the way of changing the orientation of the liquid crystal layer is constant, and the wall electrode IPS-LCD The display mode efficiency is constant regardless of high definition. Here, the display mode efficiency is a transmittance normalized by the substrate transmittance.

  One of the problems of the wall electrode IPS-LCD is light leakage around the wall structure, and the light leakage increases the transmittance of dark display, and thus reduces the contrast ratio. The cause of light leakage is an orientation change around the wall structure, which involves the cross-sectional structure of the wall structure.

  In order to form the wall structure, the organic resist PR is first patterned by photolithography, but the organic resist PR itself can be processed to have a substantially square cross-sectional shape. An alignment film is finally formed after laminating an electrode and an insulating film thereon. In this case, a solution containing an alignment film material, that is, an alignment film solution is applied. The alignment film solution tends to gather at the base of the organic resist PR due to its surface tension, and the alignment film is thickly distributed at the base of the organic resist PR. As a result, a portion having a gentle inclination at the base of the wall structure, that is, an inclined portion is formed. The cause of light leakage is presumed to be the interface reflection near the wall structure or the anchoring effect of the wall surface, but the inclined portion has the effect of increasing these. In order to reduce light leakage, the cross-sectional shape of the wall structure including the alignment film must be rectangular, but the conventional invention has not been optimized from such a viewpoint.

  An object of the present invention is to realize a liquid crystal display device that prevents light leakage from the periphery of a wall electrode and has good contrast even on a high-definition screen.

  A recess is formed at the base of the wall structure before the alignment film is formed. Specifically, an insulating film is formed between adjacent wall structures, and the thickness of the insulating film is reduced in the vicinity of the wall structure. The main means of the present invention are as follows.

  (1) A liquid crystal display device in which liquid crystal is sandwiched between a first substrate having a source electrode, a common electrode, a TFT, and a color filter, and a second substrate, and the pixels on the first substrate are The pixel is defined by a region surrounded by the video signal line and the scanning signal line. In the pixel, a first wall structure and a second wall structure are formed to face each other, and the first wall structure and the second wall structure are formed to face each other. A third wall structure is formed between the wall structures, and the first wall structure and the second wall structure have the same height and are higher than the third wall structure, 1 wall structure, the second wall structure, and the third wall structure are covered by the common electrode, the common electrode is covered by a first insulating film, and the first wall structure and the second wall structure are covered by the common electrode. A source electrode is formed on the first insulating film on the side wall of the first wall structure and the third wall structure. A space between the first wall structure and the third wall structure and between the second wall structure and the third wall structure is filled with a planarizing film, and the planarizing film is filled with the first wall structure. A concave portion is formed in the base portion of the wall structure and the second wall structure, and an alignment film is present in the concave portion.

  (2) A liquid crystal display device in which liquid crystal is sandwiched between a first substrate having a source electrode, a common electrode, a TFT, and a color filter, and a second substrate, wherein the pixels on the first substrate are: The pixel is defined by a region surrounded by the video signal line and the scanning signal line. In the pixel, a first wall structure and a second wall structure are formed to face each other, and the first wall structure and the second wall structure are formed to face each other. The wall structure is covered with a first insulating film, the source electrode is formed on the first insulating film on a side portion of the first wall structure, and the first electrode on the side portion of the second wall structure is formed. A first common electrode is formed on the two insulating films; a planarizing film is formed between the first wall structure and the second wall structure; A recess is formed in the base of the wall structure and the base of the second wall structure, and an alignment film is formed in the recess. The liquid crystal display device, characterized in that is present.

  Since the formation of the inclined portion in the vicinity of the wall structure can be prevented, light leakage from the inclined portion can be reduced and the contrast ratio can be improved. Further, if the light leakage around the wall structure is reduced, the variation in light leakage depending on the location can be reduced, so that a more uniform contrast ratio can be realized in the screen. The present invention is particularly effective for small and medium-sized liquid crystal display devices that require high-definition display.

It is a top view of the pixel in Example 1 of this invention. It is AA 'sectional drawing of FIG. It is BB 'sectional drawing of FIG. It is sectional drawing of the pixel in Example 2 of this invention. It is sectional drawing of the pixel of a comparative example. It is process drawing which shows the manufacturing process of a comparative example. It is a cross-sectional schematic diagram which shows the optical path in a comparative example. It is a top view which shows the liquid crystal aligning state of 1st wall structure WL1 vicinity.

  The alignment direction of the liquid crystal layer changes around the wall structure so as to approach the wall surface of the wall structure, and as a result, light leakage occurs around the wall structure. For alignment treatment on the wall structure, a photo-alignment method using polarized ultraviolet light is used. One cause of such a change in alignment direction is rotation of the vibration direction due to interface reflection during irradiation with polarized ultraviolet light. That is, the interface reflectance differs between the S-polarized component and the P-polarized component, and generally the S-polarized component has a higher interface reflectance. The reflected light from the wall surface changes so that the S-polarized component increases, so that the vibration direction approaches the parallel direction of the wall structure wall surface. It changes so as to approach the parallel direction. Accordingly, the alignment direction of the liquid crystal layer also changes so as to approach the parallel direction of the wall structure wall surface.

  Since polarized ultraviolet light is mainly emitted from the normal direction of the substrate, if the wall structure base is flat, interface reflection accompanied by rotation in the vibration direction occurs only on the wall surface. Since the region where light leakage occurs is limited to the wall surface of the wall structure, it can be shielded with a black matrix and does not cause a decrease in contrast. On the other hand, when there is an inclined portion, interface reflection accompanied by rotation in the vibration direction occurs in the inclined portion in addition to the wall surface. For this reason, if there is an inclined portion, the region where light leakage occurs is enlarged, and it cannot be completely shielded by the black matrix, causing a decrease in contrast.

  In the present invention, a recess functioning as a liquid pool is formed at the base of the wall structure before the formation of the alignment film. When an alignment film solution is applied thereon, the alignment film solution enters the recesses when gathered at the wall structure base by surface tension, and the alignment film is distributed so as to fill the recesses. As a result, no inclined portion is formed in the vicinity of the wall structure, and the wall structure has a substantially square cross-sectional shape. Thus, the concave portion acts as a reservoir for excess alignment film solution, and prevents formation of an inclined portion near the wall structure.

  Hereinafter, the contents of the present invention will be described in detail using examples.

  FIG. 1 is a plan view of one pixel of the liquid crystal display device of the present invention, and FIGS. 2 and 3 are cross-sectional views thereof. 2 is a cross-sectional view of the central portion of one pixel, and FIG. 3 is a cross-sectional view of a portion including the thin film transistor TFT and the contact hole CH. These cross sections are indicated by AA ′ and BB ′ in FIG. 1. 2 and 3, the first substrate SU1 and the second substrate SU2 sandwich the liquid crystal layer LC, and the first alignment film AL1 is formed on the first substrate SU1 from the side close to the liquid crystal layer LC. The first planarization film OC1, the color filter CF, and the black matrix BM are sequentially stacked.

  On the second substrate SU2, the second alignment film AL2, the second planarization film OC2, the source electrode SE, the first insulating film IL1, the common electrode CE, and the first wall are arranged from the side close to the liquid crystal layer LC. A structure WL1 and a second wall structure WL2, a second insulating film IL2, a signal wiring DL, a third insulating film IL3, a scanning wiring GL, a polysilicon layer PS, and a fourth insulating film IL4 are included. In FIG. 1, the outlines of the source electrode SE and the common electrode CE are indicated by broken lines. In FIG. 1, since the common electrode CE is distributed over almost the entire surface except for the contact hole CH, the broken line representing the outline is distributed only around the contact hole CH.

  The first wall structure WL1 is higher than the second wall structure WL2, and protrudes into the liquid crystal layer LC. The periphery of the second wall structure WL2 is filled with the second planarization film OC2, and only the top portion appears on the second planarization film OC2. The common electrode CE is distributed in the first wall structure WL1, the second wall structure WL2, and the gap between them, and the source electrode SE is the wall surface of the first wall structure WL1, the base of the second wall structure WL2, and the gap between them. Is distributed. The common electrode CE and the source electrode SE overlap with each other via the first insulating film IL1, and the overlapping portion functions as a storage capacitor. In addition to the first wall structure WL1 and the second wall structure WL2, the common electrode CE has a function of shielding potentials of adjacent pixels and wirings by being distributed in the gap between them.

  In FIG. 1, the polysilicon layer PS is connected to the signal wiring DL through the through hole, bent, and passes under the scanning wiring GL twice. A thin film transistor (TFT) is formed in a portion where the polysilicon layer PS passes through the scanning wiring GL. Therefore, in FIG. 1, two TFTs are formed in series.

  The source electrode SE is connected to the signal wiring DL through the polysilicon layer PS and the contact hole CH, and applies a potential corresponding to the image signal to the liquid crystal layer LC. The common electrode CE has an opening around the contact hole CH to prevent a short circuit with the source electrode SE. The electric lines of force EL formed between the source electrode SE and the common electrode CE are represented by broken lines in FIG. Since the electric lines of force EL are distributed so as to connect the source electrode SE on the wall surface of the first wall structure WL1 and the common electrode CE exposed at the center of the pixel, the electric lines of force EL are excluded on the second wall structure WL2. For example, the liquid crystal layer LC is distributed in parallel to the liquid crystal layer LC.

  The liquid crystal layer LC exhibits a nematic phase in a wide temperature range including room temperature. The alignment state of the liquid crystal layer LC when no voltage is applied is homogeneous alignment, and the liquid crystal director changes so as to rotate within the liquid crystal layer when an electric field is applied. Since a uniform electric field can be applied by the liquid crystal layer LC as compared with the IPS-LCD using the stripe-shaped common electrode CE and the source electrode SE, higher transmittance can be obtained. Since the liquid crystal layer LC does not exist in the portion where the first wall structure WL1 exists, the portion where the first wall structure WL1 exists becomes a non-opening portion.

  Since the first wall structure WL1 is mainly formed on the pixel boundary and the pixel boundary is shielded from light by the black matrix BM, the aperture ratio does not substantially decrease even with the first wall structure WL1. The first alignment film AL1 and the second alignment film AL2 are photo-alignment films, and a photo-alignment method is used for the alignment process. Alignment treatment is possible by irradiating polarized ultraviolet light, and alignment treatment is possible without contact. Therefore, the second alignment film AL2 applied on the first wall structure WL1 can be subjected to alignment treatment.

  The film thickness of the second planarizing film OC2 is reduced at the base of the first wall structure WL1 to form a recess. The depth D of the recess is desirably half or more than the film thickness of the second planarization film OC2. That is, as shown in FIG. 2, the second alignment film AL2 is formed on the second planarization film OC2, and the second alignment film AL2 has a thickness of about 100 nm, The thickness of the planarizing film OC2 is 1 μm to 2 μm. Therefore, if the depth of the recess is more than half the film thickness of the second planarizing film OC2, it can sufficiently serve as a liquid reservoir for the alignment film. Note that this depth refers to the depth of the deepest valley portion of the recess with respect to the envelope of the flat portion of the second planarizing film OC2.

  Such a film thickness distribution was realized as follows. A resist PR serving as a basis for the second planarization film OC2 is applied to the first wall structure WL1 and the second wall structure WL2. As a result, the resist PR is thinly distributed on the first wall structure WL1 and thicker on the second wall structure WL2. Further, since the resist PR is distributed so as to fill the step, it is thickest in the vicinity of the first wall structure WL1.

  The resist PR is a positive resist in which the light irradiation part disappears. That is, the photomask PM has openings on the first wall structure WL1 and the second wall structure WL2, and the photomask opening on the first wall structure WL1 is larger than the first wall structure WL1. The opening is wide, and the opening above the second wall structure WL2 has the same width as the second wall structure WL2. When this is exposed and etched, the cross-sectional shape becomes thin at the base of the first wall. That is, the resist PR on the first wall structure WL1 is removed, and the thick part in the vicinity thereof is also removed. Further, the resist PR on the second wall structure WL2 is also removed. This is annealed to smooth the film thickness distribution, and the state after forming the second planarizing film OC2 becomes the cross-sectional shape shown in FIG. That is, the film thickness of the planarization film OC2 is substantially uniform in the vicinity of the second wall structure WL2, and the film thickness is decreased in the vicinity of the first wall structure WL1.

  Hereinafter, a portion where the film thickness of the second planarization film OC2 in the vicinity of the first wall structure WL1 is reduced, that is, a concave portion is referred to as a liquid pool portion. The reason is that the concave portion functions as a liquid pool when the second alignment film is formed. The alignment film is formed by applying a solution containing a monomer and baking the solution, but the monomer solution tends to gather at the base of the first wall structure WL1 due to its surface tension. If there is a puddle, the monomer solution is distributed so as to fill the puddle. Therefore, when this is baked to form the second alignment film, the base portion of the first wall structure WL1 becomes substantially flat.

  The first polarizing plate PL1 is laminated outside the first substrate SU1, and the second polarizing plate PL2 is laminated outside the second substrate SU2, and the absorption axis of the second polarizing plate PL2 is oriented in the alignment processing direction. In parallel, the absorption axis of the first substrate SU1 was perpendicular to the alignment processing direction. In the liquid crystal display device of the present invention, an applied voltage of 0 V and the vicinity thereof are darkly displayed. When the pixels in this state are observed with a microscope, the inside of the pixels is uniformly dark. Further, when the contrast ratio was calculated from the ratio between the bright display transmittance and the dark display transmittance, a value of 1000: 1 or more was obtained. Thus, by forming a liquid puddle at the base of the first wall structure WL1 and flattening, the pixels in the dark display are uniformly low in transmittance, and a contrast ratio of 1000: 1 or more is obtained. .

  A cross-sectional view of the central portion of one pixel of this embodiment is shown in FIG. Compared to FIG. 2 of the first embodiment, there is no second wall structure WL2, and the structure is simplified. The source electrode SE is on the left first wall structure WL1 in FIG. 4, and the first common electrode CE1 is on the right first wall structure WL1. The second common electrode CE2 is disposed via the first insulating film IL1, and the overlapping portion of the source electrode SE and the second common electrode SE2 functions as a storage capacitor. An electric field between the source electrode SE and the first common electrode CE1 is applied to the liquid crystal layer LC, and electric lines of force EL between the source electrode SE and the first common electrode CE1 are indicated by broken lines in FIG. The density of the electric lines of force EL is substantially constant throughout the liquid crystal layer LC, and a substantially uniform electric field is applied across the entire liquid crystal layer LC. In the pixel structure shown in FIG. 4, electric lines of force EL are formed so as to connect between the source electrode SE and the first common electrode CE1 existing at both ends of the pixel, and the narrow pixel corresponding to high definition is formed. It is especially effective in cases.

  The film thickness of the second planarizing film OC2 is reduced at the base of the first wall structure WL1 at both ends of the pixel, forming a liquid pool or a recess. The depth D of the recess is desirably half or more of the film thickness of the second planarizing film OC2 for the same reason as in the first embodiment. Note that this depth refers to the depth of the deepest valley portion of the recess with respect to the envelope of the flat portion of the second planarizing film OC2.

  The cross-sectional structure of this example was formed as follows. When the resist PR which becomes the basis of the second planarization film OC2 is applied to the first wall structure WL1, the resist PR is distributed thinly on the first wall structure WL1 and is distributed most thickly in the vicinity thereof.

  The photomask PM has an opening on the first wall structure WL1, and the opening of the photomask PM is wider than the first wall structure WL1. When this is exposed and etched, the resist PR is removed from above the first wall structure WL1, and the thick portion in the vicinity thereof is also removed. This is annealed to smooth the film thickness distribution, and the state after forming the second planarizing film OC2 is the cross-sectional view shown in FIG. In this structure, the film thickness decreases in the vicinity of the first wall structure WL1 and becomes a liquid pool. FIG. 4 shows a state in which the second alignment film AL2 is formed on the first wall structure WL1 due to the collection of the second alignment film AL2 in the liquid pool.

  When the dark display pixel was observed with a microscope, the inside of the pixel was uniformly dark and a contrast ratio of 1000: 1 or more was obtained. As described above, in the pixel structure of the present embodiment as well, a liquid pool is formed at the base portion of the first wall structure WL1 and is flattened, whereby the inside of the pixel has a low transmittance uniformly in dark display, and 1000: 1. The above contrast ratio was obtained.

Comparative example

  In Example 1, no liquid pool was formed, and the thickness of the second planarization film OC2 was made substantially constant at the base of the first wall structure as shown in FIG. As a result, the base portion of the second wall structure WL2 was not flat, and an inclined portion was formed as shown in FIG. Such a film thickness distribution was realized as shown in FIG. FIG. 6A is a cross-sectional view at the center of the pixel. When a resist PR is applied to the pixel, it is thin on the first wall structure WL1 as shown in FIG. 6B, and is formed on the second wall structure WL2. Thickly distributed.

  This is processed with the photomask PM shown in FIG. The photomask PM has openings on the first wall structure WL1 and the second wall structure WL2, and both openings have the same width as the first wall structure WL1 and the second wall structure WL2, respectively. It is. When this is exposed and etched, the resist PR has a cross-sectional shape as shown in FIG. That is, the resist PRRE on the first wall structure WL1 is removed, but the thick part in the vicinity thereof is not completely removed but remains a little.

  FIG. 6E shows the state after annealing to smooth the film thickness distribution to obtain the second planarization film OC2, and the film thickness of the planarization film OC2 is almost in the vicinity of the second wall structure WL2. It becomes uniform and no puddle is formed. When the monomer solution is applied thereon, it collects at the base of the second wall structure WL2 due to surface tension, but since there is no liquid pool, an inclined portion is formed at and near the base of the second wall structure WL2. When this is fired, as shown in FIG. 6F, the second alignment film AL2 is formed while maintaining the shape when the monomer solution is applied.

  When the dark display pixel was observed with a microscope, light leakage was observed in the vicinity of the first wall structure WL1. Further, when the contrast ratio was calculated from the ratio between the bright display transmittance and the dark display transmittance, it was reduced to a value lower than 200: 1.

  Light leakage in the vicinity of the first wall structure WL1 is considered to be caused by a change in the orientation in the alignment processing direction due to interface reflection during the optical alignment processing as shown in FIG. In FIG. 7, the first wall structure WL1 is shown in a sectional view, but the polarization state at each stage during the photo-alignment process is shown in a plan view, and polarized ultraviolet light incident on the first wall structure WL1. The vibration direction is set to 45 degrees with respect to the wall surface as shown in FIG. As shown in FIG. 7B, the polarized ultraviolet light used in the photo-alignment method is reflected at the interface of the second alignment film AL2, but the interface reflectivity differs between the S-polarized component SPL and the P-polarized component PPL. The polarization component SPL has a higher interface reflectance.

  As shown in FIG. 7C, the reflected light on the wall surface changes in the vibration direction so as to approach the parallel direction of the wall surface of the first wall structure WL1 because the S-polarized component SPL increases. If the component is effective, the orientation processing direction changes so as to approach the parallel direction of the wall surface of the second wall structure WL2. Alternatively, as shown in FIG. 7D, the transmitted light increases in the P-polarized component PPL, so that the vibration direction changes away from the parallel direction of the first wall structure WL1, and the transmitted component is effective. For example, the orientation process direction changes away from the parallel direction of the wall surface of the first wall structure WL1.

  Since polarized ultraviolet light is mainly emitted from the normal direction of the substrate, if the base of the first wall structure WL1 is flat, interface reflection accompanied by rotation in the vibration direction occurs only on the wall surface. Since the region where light leakage occurs is limited to the wall surface of the first wall structure WL1, it can be shielded by the black matrix, and the contrast ratio does not decrease. On the other hand, when there is an inclined portion, interface reflection accompanied by rotation in the vibration direction occurs in the inclined portion in addition to the wall surface. For this reason, the light leakage occurrence area is enlarged, and the contrast ratio is lowered without being completely shielded by the black matrix.

  FIG. 8 is a plan view showing the liquid crystal alignment state in the vicinity of the first wall structure WL1, and the distribution of the liquid crystal molecules LCM2 in which the alignment direction is changed from the alignment processing direction AD as shown in FIG. If it is limited to the very vicinity of the wall structure WL1, it is shielded by the black matrix BM and does not cause a decrease in contrast ratio. That is, in FIG. 8A, only the same liquid crystal molecules LCM1 as the alignment processing direction AD are distributed outside the black matrix BM. On the other hand, as shown in FIG. 8B, if the distribution of the liquid crystal molecules LCM2 in which the alignment direction is changed from the alignment processing direction AD extends to a portion away from the first wall structure WL1, the light leakage due to this The contrast ratio is lowered without being completely shielded by the black matrix. FIGS. 8A and 8B show the case where the liquid crystal alignment direction in the vicinity of the first wall structure WL1 is changed so as to approach the parallel direction of the wall surface of the first wall structure WL1. The same holds true when the liquid crystal alignment direction in the vicinity of the first wall structure WL1 changes so as to move away from the wall surface of the first wall structure WL1.

  WL1 ... first wall structure, WL2 ... second wall structure, SU1 ... first substrate, SU2 ... second substrate, BM ... black matrix, OC1 ... first planarization film, OC2 ... second flatness AL1 ... first alignment film, AL2 ... second alignment film, LC ... liquid crystal, SE ... source electrode, CE ... common electrode, EL ... electric field lines, IL1 ... first insulating film, IL2 ... first 2 insulating film, IL3 ... third insulating film, IL4 ... fourth insulating film, CF ... color filter, CH ... contact hole, DL ... signal wiring, GL ... scanning wiring PS ... polysilicon layer, DL ... signal wiring D: Depth of recess, PR: Resist.

Claims (6)

A liquid crystal display device in which liquid crystal is sandwiched between a first substrate and a second substrate,
The pixel on the first substrate is defined by a region surrounded by the video signal line and the scanning signal line,
In the pixel, a first wall structure and a second wall structure are formed to face each other, and a third wall structure is formed between the first wall structure and the second wall structure. A height of the third wall structure is lower than a height of the first wall structure and the second wall structure;
A source electrode is formed on the side of the first wall structure and the second wall structure, and a common electrode is formed on the top of the third wall structure,
A space between the first wall structure and the third wall structure and between the second wall structure and the third wall structure is filled with a planarizing film, and the planarizing film is filled with the first wall structure. A concave portion is formed in the base portion of the wall structure and the second wall structure, and an alignment film is present in the concave portion.   2. The first wall structure according to claim 1, wherein the first wall structure is formed at a first end of the pixel, and the second wall structure is formed at a second end of the second wall structure. Liquid crystal display device.   The depth of the concave portion in the base portion of the first wall structure and the second wall structure of the flattening film is not less than half of the film thickness of the flattening film. Liquid crystal display device. A liquid crystal display device in which liquid crystal is sandwiched between a first substrate and a second substrate,
The pixel on the first substrate is defined by a region surrounded by the video signal line and the scanning signal line,
The pixel is formed with a first wall structure and a second wall structure facing each other,
A source electrode is formed on the side of the first wall structure, a common electrode is formed on the side of the second wall structure,
A planarization film is formed between the first wall structure and the second wall structure, and the planarization film is a recess in the base portion of the first wall structure and the base portion of the second wall structure. A liquid crystal display device, wherein an alignment film is present in the recess.   5. The first wall structure is formed at a first end of the pixel, and the second wall structure is formed at a second end of the second wall structure. The liquid crystal display device described.   The depth of the concave portion in the base portion of the first wall structure and the second wall structure of the planarizing film is not less than half of the film thickness of the planarizing film. Liquid crystal display device.

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