JPH09230379A - Liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bright display, to obscure the wirings between pixels and to improve visibility by allowing the transmission of light as much as possible. SOLUTION: The intersected parts of gate wirings and source wirings 2 are provided with switching elements near these parts. The upper parts of these switching elements are provide with two kinds of interlayer insulating films 5 and 6 varying in refractive index. The upper parts of these interlayer insulating films 5 and 6 are provided with pixel electrodes 3 connected to the switching elements. The interlayer insulating films 5 and 6 form optical refracting means. As a result, the light is refracted at the boundary surfaces between the interlayer insulating films 5 and 6 and the light is introduced to the pixel parts on the light shielding materials, such as wirings, as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device having a switching element such as a thin film transistor (hereinafter referred to as TFT) and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIG. 13 is a sectional view of one pixel portion of a conventional projection liquid crystal display device disclosed in Japanese Patent Laid-Open No. 4-372928.

In FIG. 13, an active matrix type liquid crystal display device has a TFT 52, wiring and pixel electrodes (not shown) provided on an insulating substrate 59 (hereinafter referred to as a TFT substrate 59) made of glass or the like. There is. Then, the counter substrate 60 provided with the light shielding film 61 and the TFT substrate 59.
The liquid crystal 57 is sandwiched between and. Light is emitted from a light source (not shown) from the counter substrate 60 side, the light is incident on the liquid crystal 57 via the prism sheet 58, and the transmittance of the liquid crystal 57 is changed to project an image. By refracting the light with the prism element 62 of the prism sheet 58, the light can be incident on the entire surface of the opening without being blocked by the light shielding film 61.

Although not shown, a direct-viewing type liquid crystal display device includes a liquid crystal display device in which a large aperture ratio is obtained by stacking wiring and pixels with an interlayer insulating film interposed therebetween (Japanese Patent Laid-Open No. Sho 6-62).
1-156025).

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the liquid crystal display device disclosed in Japanese Patent No. 928, the light shielding film 6
A bright screen can be obtained because the amount of light blocked by 1 is small, but the prism sheet 58 is expensive, so the cost is high. As the pixel pitch becomes finer with higher definition, the light-shielding film 6
1 and the prism element 62 of the prism sheet 58 take time to align. Since the prism sheet 58 is provided on the back side of the counter substrate 60, it is difficult to reduce the thickness. Since diffused light is used, the light utilization efficiency is improved. There is a problem such as low. The biggest problem is that a part of the light incident on the liquid crystal is shielded by the wiring and the TFT provided on the TFT substrate 59 side.

Further, in the liquid crystal display device disclosed in Japanese Patent Laid-Open No. 61-156025, although the pixel electrode is provided on the wiring to increase the light transmission area, the light is still blocked by the wiring.

The present invention has been made in order to solve such a problem, and an object thereof is to provide a liquid crystal display device which transmits as much light as possible to obtain a bright display and a manufacturing method thereof. It is to be. Another object of the present invention is to provide a liquid crystal display device in which wiring between pixels is inconspicuous and visibility is improved, and a manufacturing method thereof.

[0008]

A liquid crystal display device according to the present invention includes a substrate, a scanning wiring and a signal wiring provided on one surface of the substrate, and an intersection of the scanning wiring and the signal wiring. A liquid crystal display device comprising: a switching element provided in the vicinity; an interlayer insulating film provided on the switching element; and a pixel electrode provided on the interlayer insulating film and connected to the switching element. The interlayer insulating film has a first portion having a first refractive index and a second portion having a second refractive index different from the first refractive index, The boundary surface between the portion and the second portion has a surface inclined with respect to a surface orthogonal to the one surface of the substrate, whereby the above object is achieved.

With the above structure, the liquid crystal display device according to the present invention is capable of refracting incident light and irradiating light to the pixel electrode portion overlapping the wiring through the interlayer insulating film, which is apparent. The aperture ratio can be increased, and it has a function of making non-transmissive portions such as wiring and auxiliary capacitance electrodes inconspicuous. This effect is more effective when the liquid crystal display device according to the present invention is used for a high-definition display device such as a projection panel.

The liquid crystal display device includes a counter substrate facing the one surface of the substrate, a liquid crystal sealed between the substrates, and a counter electrode provided on the counter substrate. May be further provided.

The liquid crystal display device is provided on the counter substrate facing the one surface of the substrate, the liquid crystal sealed between the substrate and the counter substrate, and provided on the interlayer insulating film. An electrode facing the pixel electrode in a direction parallel to the surface of the interlayer insulating film may be further provided.

The liquid crystal display device according to the present invention, due to the above structure, refracts incident light and cannot easily increase the aperture ratio, IPS (In-Plane Switching).
Even in the mode liquid crystal display device, it is possible to increase the apparent aperture ratio and to make the non-transmissive portions such as wiring and auxiliary capacitance electrodes inconspicuous. Due to this action, a display device such as a large-sized television having a wide viewing angle and high contrast can be obtained with a beautiful display.

At least one of the first portion and the second portion may have a substantially triangular cross-section.

The liquid crystal display device according to the present invention has an advantage that it can be formed more easily than a microlens having the same effect and has excellent productivity because of the above structure.

The first portion may be provided on at least one of the scanning wiring and the signal wiring, and the dielectric constant of the first portion may be smaller than that of the second portion.

The interlayer insulating film may have photosensitivity.

A method of manufacturing a liquid crystal display device according to the present invention comprises:
A step of forming a plurality of switching elements in a matrix on the front surface of the substrate and forming scan wirings and signal wirings connected to the switching elements so as to intersect with each other, and from the back surface of the substrate to the substrate. A step of forming a first interlayer insulating film having a first refractive index on a region of the surface of the substrate that is shielded when irradiated with light; and a step of forming a first interlayer insulating film on the surface of the substrate other than the region. The surface of the second interlayer insulating film having the second refractive index in contact with the first interlayer insulating film and the second interlayer insulating film is a surface inclined with respect to the surface orthogonal to the surface of the substrate. And the first step
Alternatively, a step of forming a pixel electrode connected to the switching element on the second interlayer insulating film is included, whereby the above object is achieved.

In the step of forming the pixel electrode, the electrode facing the pixel electrode connected to the switching element is
The method may include a step of providing it on the first or second interlayer insulating film.

A method of manufacturing a liquid crystal display device according to the present invention comprises:
By including the above steps, formation can be facilitated, dimensional accuracy can be improved, and cost increase can be suppressed.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 is a plan view showing the structure of one pixel portion of an active matrix substrate in a liquid crystal display device according to Embodiment 1 of the present invention.

A plurality of pixel electrodes 3 are provided in a matrix on the active matrix substrate. A gate wiring 1 and a signal wiring as scanning wirings are arranged so as to pass around the pixel electrodes 3 and cross each other at right angles. Source wiring 2 is formed. The gate wiring 1 and the source wiring 2 are formed so that a part thereof overlaps the outer peripheral portion of the pixel electrode 3. Also, the gate wiring 1
A TFT 4 serving as a switching element connected to the pixel electrode 3 via a contact hole (not shown) is formed in the vicinity of an intersection of the source line 2 and the source line 2. The switching element is not limited to the TFT and may be a switching element such as MIM. In that case, the scanning wiring is provided on the counter substrate. Although not shown here, additional capacitance wiring (Cs wiring) may be provided.

FIG. 2 is a sectional view taken along the line AA 'of the liquid crystal display device of FIG.

In FIG. 2, the transparent insulating substrate 9 (hereinafter,
A gate wiring and a gate insulating film (not shown) are provided on a TFT substrate 9), a semiconductor layer (not shown) of the TFT is provided, and a source wiring 2 is provided. Two types of interlayer insulating films 5 and 6 are provided so as to cover the source wiring 2, and a pixel electrode 3 is further provided thereon via a contact hole (not shown). An alignment film (not shown) is formed on each of the pixel electrode 3 and the counter electrode 8 formed on the counter substrate 10, and the liquid crystal 7 is sealed between the alignment films. . At this time, the gap between the TFT substrate 9 and the counter substrate 10 is maintained by a spacer (not shown).

In this embodiment, the interlayer insulating film 5 is made of a fluorine resin having a refractive index of 1.3, and the interlayer insulating film 6 is made of a polyimide resin having a refractive index of 1.7. The interlayer insulating film 6 is shown in FIG.
As shown in FIG. 5, the cross-sectional shape was formed so as to have a shape having a part of an inverted triangle (trapezoidal shape). In this way, when the materials of the interlayer insulating films 5 and 6 are selected so that the refractive index of the interlayer insulating film 6 is larger than that of the interlayer insulating film 5, light is emitted at the interface between the interlayer insulating films 5 and 6. By being refracted, the light is also incident on the portion 30 of the pixel electrode 3 that overlaps the source wiring 2. At this time, the angle of light incident on the liquid crystal 7 changes depending on the film thickness and taper angle of the interlayer insulating films 5 and 6 and the area of the pixel electrode 30 overlapping the source wiring. Although the interlayer insulating films 5 and 6 are formed to have the same height in this embodiment, the heights of the interlayer insulating film 5 and the interlayer insulating film 6 may not be the same. . In order to improve productivity, as shown in FIG. 3, the interlayer insulating film (interlayer insulating film 32) formed later is the interlayer insulating film (interlayer insulating film 3) previously formed.
You may form so that the upper part of 1) may be covered.

The active matrix substrate of Embodiment 1 is constructed as described above.

Next, an example of a method of manufacturing the liquid crystal display device having the active matrix substrate of the first embodiment will be described with reference to FIGS. 4 and 5.

First, on the transparent insulating substrate 9 made of a glass substrate or the like, the gate wiring 1 made of a metal such as Al, Ta, Cr or the like (including the gate electrode of the TFT 4), SiN _x ,
A gate insulating film (not shown) made of SiO ₂ or the like and TF
A semiconductor layer made of Si or the like forming T4, a channel protective layer made of SiN _x, and an n ⁺ layer are sequentially formed and patterned. Note that the channel protective film may not be provided.

Next, a source wiring 2 (including a source electrode and a drain electrode of the TFT 4) made of a metal such as A1, Ta and Cr is formed on the TFT substrate (FIG. 4A).
Needless to say, these wirings may be formed in two or more layers for the purpose of lowering resistance and redundancy.

The manufacturing process up to this point can be carried out in the same manner as the conventional method for manufacturing an active matrix substrate.

Further, a fluorine resin is formed in a region of the TFT substrate where the source wiring or the gate wiring is not provided by a spin coating method, a slot coating method, or a roll coating method to have a film thickness of, for example, 3 μm. The insulating film 5 is formed (FIG. 4B). This film thickness corresponds to the portion 30 of the pixel electrode 3 that overlaps with the source wiring 2.
And the dielectric constant of the film of resin or the like.

After that, a photoresist 42 is applied on the interlayer insulating film 5 and an exposure process is performed using the mask 41 (FIG. 4C). At this time, a backside exposure method using the wiring as a mask may be used. Exposure is performed according to a desired pattern provided on the mask 41, and the pattern of the mask 41 is transferred to a resist as shown in FIG. After that, etching treatment is performed with an alkaline solution. By this treatment, only the exposed portion is etched by the alkaline solution, the hole 44 for forming the interlayer insulating film 6 is formed, and the interlayer insulating film 55 having the surface inclined with respect to the surface of the substrate 9 is formed. Formed (FIG. 5A). After that, the resist 43 is removed (FIG. 5B). As a result, the interlayer insulating film 55 after removing the resist is formed as shown in FIG. Although not shown, a contact hole for connecting the pixel electrode 3 and the TFT 4 is formed through the interlayer insulating film 5 in the above process. At this time, productivity is improved by using a low-viscosity resin as the material of the interlayer insulating film 5, and pre-baking and drying are performed before patterning to prevent adverse effects such as displacement of dimensions during main curing. Is more preferable.

When a resin having poor surface adhesion is used, the adhesion may be improved at this stage by roughening the surface by ashing or irradiation with light. At this time, if the photoresist 43 is also removed at the same time, the number of steps does not increase. However, it should be noted that if the surface is too rough, the direction of light will change, or the flatness of the surface will be lost, resulting in poor alignment.

After that, in a state in which a photosensitizer or the like is embedded in the contact portion between the pixel electrode 3 and the TFT 4, a highly transparent polyimide (for example, an acid dianhydride containing hexafluoropropylene) is formed in the hole 44 by a squeegee method or a spin coating method. An interlayer insulating film 56 is formed by embedding a material having a refractive index of 1.7 in combination with diamine (FIG. 5C). At this time, it has been found that the polyimide resin may remain on the surface of the fluorine-based resin in practical use.
After removing the photosensitizer embedded in the contact area,
A contact material such as metal is deposited on the contact portion. Then, it is dried to complete the optical refraction means using the interlayer insulating films 55 and 56 as shown in FIG. 5C.

Then, as shown in FIG. 5D, the pixel electrode 3
Then, ITO is formed by a sputtering method and patterned. As a result, the pixel electrode 3 is connected to the drain electrode of the TFT 4 via the contact hole penetrating the interlayer insulating film 5.

Then, the TFT substrate 9 thus manufactured and the counter substrate 10 on which the counter electrode 8 is formed are bonded together. At this time, the gap between the TFT substrate 9 and the counter substrate 10 was kept constant by the sealing material at the peripheral portion and the spacer (not shown) at the other portions. After that, TFT
A liquid crystal panel was prepared by enclosing the liquid crystal 7 between the substrate 9 and the counter substrate 10. Further, an external drive circuit (not shown) was connected and a backlight (not shown) was arranged to manufacture the liquid crystal display device of the first embodiment.

The liquid crystal display device according to the present invention does not particularly require an expensive prism sheet, but it is obviously better to dispose a prism sheet called a viewing angle correction member between the backlight and the liquid crystal panel. because,
Since liquid crystal has a viewing angle, it is not an effective use of the light source to illuminate a portion outside the viewing angle. By using the prism sheet, the display within the viewing angle becomes brighter and higher brightness can be realized. Of course, such a sheet is not necessary if a highly parallel backlight is used.

As a material for the interlayer insulating films 55 and 56 of the active matrix substrate obtained as described above, a material having a high transparency, specifically, a transmittance of 90 in the hyper-light region is 90.
% Or more is preferably used. As such a material, for example, epoxy resin (refractive index = 1.55 to
1.61), acrylic resin (refractive index = 1.48 to 1.5
2), phenol resin (refractive index = 1.5 to 1.7), allyl resin (refractive index = 1.5 to 1.57) and the like can be used. In addition, it is more preferable to use a material having photosensitivity as the material used for the interlayer insulating film 5 because it is not necessary to use a resist and the manufacturing process can be shortened.

(Embodiment 2) FIG. 7 is a sectional view showing the structure of one pixel portion of an active matrix substrate in a liquid crystal display device according to Embodiment 2 of the present invention. In the following description, the description of the same parts as those in the first embodiment will be omitted.

In this embodiment, the materials of the interlayer insulating films 35 and 36 are selected so that the refractive index of the interlayer insulating film 35 is larger than that of the interlayer insulating film 36. In particular,
Acrylic resin having a refractive index of 1.52 was used as the material of the interlayer insulating film 35, and fluorine resin having a refractive index of 1.28 was used as the material of the interlayer insulating film 36. And Embodiment 1
The inter-layer insulating film 35 having a shape (trapezoidal shape) having a part of an inverted triangular cross-section is formed so that the optical refraction means formed by two types of inter-layer insulating films are opposite to the active matrix substrate of FIG. Provided. In this embodiment, the light shielding film 11 having a line width smaller than that of the wiring material is provided on the counter substrate 10. The light-shielding film provided on the counter substrate is generally used in a direct-view display device in which a color filter (not shown) is provided on the counter substrate. The light-shielding film 11 is provided in order to hide the misalignment when the color registration accuracy of each color of the color filter is not so good.
Therefore, the line width of the light shielding film 11 may be a width (about 1 to 3 μm) that can hide the misalignment.

At this time, by using a fluorine-based resin having a dielectric constant of 2.1 and a low dielectric constant as the material of the interlayer insulating film 36, the stray capacitance that can be heard between the wiring 2 and the pixel electrode 3 can be reduced, and the cross capacitance can be reduced. Display defects such as talk can be eliminated. Therefore, in this embodiment, the material used for the interlayer insulating film 6 is a material having a low dielectric constant, preferably a material having a dielectric constant of 4 or less, and a thickness of 3 μm or more. Although the interlayer insulating films 35 and 36 are formed so that their respective heights are the same in this embodiment, the interlayer insulating film 35 is formed similarly to the first embodiment.
Does not have to be the same as the height of the interlayer insulating film 36.
In order to improve the productivity, the interlayer insulating film (interlayer insulating film 35 in this embodiment) formed later covers the upper part of the interlayer insulating film (interlayer insulating film 36 in this embodiment) formed earlier. You may form in.

The active matrix substrate of Embodiment 2 is constructed as described above. The liquid crystal display device of Embodiment 2 can be manufactured as follows.

The source wiring 2 is formed on the TFT substrate 9 by the same method as in the first embodiment, and the insulating film 8 having a thickness of 5 μm is formed by a spin coating method using a fluorine resin as a material.
0 is formed (FIG. 8A). Then, after applying a photoresist 82 on the insulating film 80, an exposure process is performed using the mask 83 (FIG. 8B), and the pattern of the mask 83 is transferred to the resist 82 (FIG. 8C). After that, the interlayer insulating film 36 is formed by performing etching by the dry etching method (FIG. 8D). Photoresist 8
After removing 4 (FIG. 9 (a)), a photosensitive acrylic resin is embedded in the hole 87 by a spin coating method.
The interlayer insulating film 35 is formed (FIG. 9B). This photosensitive acrylic resin is exposed according to a desired pattern and then subjected to etching treatment with an alkaline solution. By this treatment, only the exposed portion is etched by the alkaline solution to penetrate the interlayer insulating film 35 and form a contact hole (not shown) for connecting the pixel electrode 3 and the TFT 4.

As described above, since the photosensitive acrylic resin is used, the patterning can be performed only by the photo process. Therefore, not only the interlayer insulating film 35 but also the one having photosensitivity can be provided with the photosensitivity. It is preferable to have it.

After that, ITO which becomes the pixel electrode 3 is formed by sputtering and patterned. As a result, the pixel electrode 3 is connected to the drain electrode of the TFT 4 via the contact hole penetrating the interlayer insulating film 35.

Then, the TFT substrate 9 thus manufactured and the counter substrate 10 on which the counter electrode 8 is formed are bonded together. At this time, the peripheral portion is sealed with a sealing material (not shown), and the other portion is covered with a spacer (not shown).
The gap between the FT substrate 9 and the counter substrate 10 was kept constant. The subsequent steps were performed in the same manner as in Embodiment 1 to manufacture the liquid crystal display device of Embodiment 2.

(Embodiment 3) FIGS. 10 and 11 show an IPS (In-Plane Switch) known as an example of a liquid crystal display device in which the aperture ratio cannot be easily increased.
An example in which the present invention is applied to a liquid crystal display device called ng) mode will be shown.

The IPS mode is not the method of applying an electric field between the pixel electrode and the counter electrode (that is, the vertical direction when viewed from the display direction) used in Embodiments 1 and 2 and the like.
This is a system in which two electrodes are provided on the FT substrate side and an electric field is applied in the horizontal direction when viewed from the display direction (for details, see pages 130 to 135 of the December 1995 issue of Nikkei Microdevices). This method has an extremely wide viewing angle because an electric field is applied in the lateral direction, but has a problem that the aperture ratio cannot be easily increased due to the structure. Therefore, in order to solve this problem, a method of superposing the wiring and the counter electrode via an interlayer insulating film has been proposed (reference number 95 by the applicant of the present application, filed on the same date as the filing date of the present application. -3293
Patent application; Koyama). In the third embodiment, the method is further improved.

FIG. 10 is a plan view showing the structure of one pixel portion of the active matrix substrate in the liquid crystal display device according to the third embodiment of the present invention, and FIG. 11 is a sectional view taken along the line AA ′ of FIG. is there. In the following description, description of the same parts as those in Embodiments 1 and 2 will be omitted.

In this embodiment, the interlayer insulating film 1 is formed on the TFT substrate 109 by using fluorine resin having a refractive index of 1.3.
No. 05 is formed, and the interlayer insulating films 106a and 106b are formed using a polyimide resin having a refractive index of 1.7 so that the cross-sectional shape thereof has a part having an inverted triangular shape (trapezoidal shape). In this case, the gate wiring 101 and the source wiring 1
Counter electrode 1 instead of the counter electrode that is stacked with 02
Not only the lower part of 08, but the drive electrode 1 instead of the pixel electrode
The interlayer insulating film 106b is also provided under the electrode 03 to allow light to enter the upper portion of the drive electrode 103. With this structure, the wiring can be made inconspicuous, and display quality such as contrast can be improved. Note that in FIGS. 10 and 11, the gate wiring 101 and the source wiring 102 are formed.
Although the lower layer wiring is thicker than the driving electrode 103, the line width of the gate wiring 101 or the source wiring 102 may be the same as or narrower than the driving electrode 103.

As described above, the active matrix substrate of Embodiment 3 is constructed. Note that, also in the present embodiment, the interlayer insulating films 105 and 1 are made to have the same height.
Although the layers 06a and 106b are formed, the interlayer insulating film 1
The heights of 05, 106a and 106b need not be the same. In order to improve productivity, an interlayer insulating film to be formed later (interlayer insulating films 106a and 10a in this embodiment) is formed.
6b) may be formed so as to slightly cover the upper portion of the previously formed interlayer insulating film (interlayer insulating film 105 in this embodiment).

A method of manufacturing the active matrix liquid crystal display device of Embodiment 3 will be described below with reference to FIG.

First, similarly to the first embodiment, the gate wiring, the gate insulating film, the semiconductor layer,
A channel protective layer and a source wiring are formed. In addition,
Also in this embodiment, the channel protective film may not be provided. Next, as shown in FIG. 12A, an interlayer insulating film 105 made of a fluororesin is formed. Similar to the second embodiment, a photo step of exposing according to a desired pattern and a patterning step by dry etching are performed on the interlayer insulating film 105, and contact holes penetrating the interlayer insulating film 105 and the interlayer insulating films 106 a and 1 a.
Holes 81 and 82 for forming 06b are formed (FIG. 12).
(B)). Thereafter, similarly to the first embodiment, the interlayer insulating films 106a and 106b are formed by filling the holes 81 and 82 with a polyimide resin (FIG. 12).
(C)). At this time, the contact portion between the drain electrode and the drive electrode 3 is left open.

After this, as shown in FIG.
Drive electrode 10 made of low-resistance metal such as 1, Ta, and Cr
3 and the counter electrode 108 are formed.

Then, the TFT substrate 109 thus manufactured and the counter substrate 110 on which the counter electrode is not formed.
And paste together. At this time, the TF is surrounded by a sealing material and the other parts by a spacer (not shown).
The gap between the T substrate 109 and the counter substrate 110 was kept constant. After that, the liquid crystal display device of the third embodiment was manufactured in the same manner as in the first embodiment.

(Embodiment 4) In the liquid crystal display device according to Embodiment 4 of the present invention, a part of the liquid crystal display device using the IPS mode described in Embodiment 3 has a triangular sectional shape as described in Embodiment 2. The inter-layer insulating film 36 having the shape (trapezoidal shape) is used. A photosensitive polyimide resin was used as the material of the interlayer insulating film 35, and a fluorine-based resin was used as the material of the interlayer insulating film 36. As a result, a liquid crystal display device with high display quality with reduced parasitic capacitance was obtained.

[0057]

As described above, according to the present invention, the interlayer insulating film has at least two kinds of portions having different refractive indexes, and the boundary surface of these portions is a surface orthogonal to the surface of the substrate. Have a surface inclined with respect to, and these portions form an optical refraction means to refract incident light, and irradiate the pixel electrode portion overlapped with the wiring with the light through the interlayer insulating film. It is possible to increase the apparent aperture ratio. As a result, the liquid crystal display device according to the present invention has the effect of making the non-transmissive portions such as wiring and auxiliary capacitance electrodes inconspicuous. This effect is particularly great when the liquid crystal display device according to the present invention is used in a high definition display device such as a projection panel. Further, the liquid crystal display device according to the present invention has an advantage that it can be formed more easily than a liquid crystal display device using a microlens having the same effect. The method of manufacturing a liquid crystal display device according to the present invention has an advantage that the above liquid crystal display device can be easily formed.

Further, according to the present invention, even in an IPS mode liquid crystal display device in which the aperture ratio cannot be easily increased, the apparent aperture ratio can be increased, and non-transmissive portions such as wirings and auxiliary capacitance electrodes can be provided. You can make it inconspicuous. As a result, the liquid crystal display device according to the present invention provides a display device such as a large-sized television having a wide viewing angle and high contrast with beautiful display. Further, the liquid crystal display device according to the present invention has an advantage that it can be formed more easily than a liquid crystal display device using a microlens having the same effect. The method of manufacturing a liquid crystal display device according to the present invention has an advantage that the above liquid crystal display device can be easily formed.

By using a material having a low dielectric constant for the interlayer insulating film provided on the scanning wiring and the signal wiring, it is possible to suppress an increase in parasitic capacitance between the wiring and the pixel electrode.

Further, one of the portions of the interlayer insulating film having a different refractive index is formed to have a substantially triangular shape or a substantially inverted triangular shape, so that it has a microlens which similarly provides an optical refraction means. It has an advantage that it can be formed more easily than a liquid crystal display device.

Further, according to the method of manufacturing a liquid crystal display device of the present invention, at least two kinds of portions having different refractive indexes are provided in the interlayer insulating film to form the optical refraction means, thereby refracting the incident light to cause the interlayer light to refract. It becomes possible to irradiate light to the pixel electrode portion which is overlapped with the wiring through the insulating film,
A liquid crystal display device that can increase the apparent aperture ratio and that has the effect of making non-transmissive portions such as wiring and auxiliary capacitance electrodes inconspicuous can be manufactured easily and with high dimensional accuracy. The rise can be suppressed.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of one pixel portion of an active matrix substrate in a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA ′ of the active matrix substrate in the liquid crystal display device of FIG.

FIG. 3 is an active matrix substrate 1 in another example of the liquid crystal display device according to Embodiment 1 of the present invention.
It is sectional drawing of a pixel part.

4A to 4D are views showing manufacturing steps of the liquid crystal display device according to the first embodiment of the present invention.

5A to 5D are views showing manufacturing steps of the liquid crystal display device according to the first embodiment of the present invention.

FIG. 6 is a perspective view showing a part of the shape of an interlayer insulating film in the liquid crystal display device according to the first embodiment of the present invention.

FIG. 7 is a sectional view of an active matrix substrate in a liquid crystal display device according to a second embodiment of the present invention.

8A to 8D are diagrams showing a manufacturing process of a liquid crystal display device according to a second embodiment of the present invention.

9A to 9C are views showing manufacturing steps of the liquid crystal display device according to the second embodiment of the present invention.

FIG. 10 is a plan view of one pixel portion of an active matrix substrate in a liquid crystal display device according to a third embodiment of the present invention.

11 is a cross-sectional view taken along the line AA ′ of the active matrix substrate in the liquid crystal display device of FIG.

12A to 12D are diagrams showing a manufacturing process of the liquid crystal display device according to the third embodiment of the present invention.

FIG. 13 is a cross-sectional view of one pixel portion of an active matrix substrate in a conventional projection type liquid crystal display device.

[Explanation of symbols]

 1 gate wiring 2 source wiring 3 pixel electrode 4 TFT (switching element) 5 interlayer insulating film 1 6 interlayer insulating film 2 7 liquid crystal 8 counter electrode 9 transparent insulating substrate (TFT substrate) 10 counter substrate 11 light shielding film 52 TFT 57 liquid crystal 58 Prism sheet 59 Transparent insulating substrate (TFT substrate) 60 Counter substrate 62 Prism element

Claims (8)

[Claims] 1. A substrate, a scanning wiring and a signal wiring provided on an upper surface of one surface of the substrate, and a switching element provided near an intersection of the scanning wiring and the signal wiring.
An interlayer insulating film provided on the switching element,
A liquid crystal display device comprising: a pixel electrode provided on the interlayer insulating film and connected to the switching element, wherein the interlayer insulating film has a first portion having a first refractive index;
A second portion having a second refractive index different from the first refractive index, and an interface between the first portion and the second portion is orthogonal to the one surface of the substrate. Has a surface inclined with respect to
Liquid crystal display. 2. A counter substrate, which faces the one surface of the substrate, a liquid crystal sealed between the substrate and the counter substrate, and a counter electrode provided on the counter substrate. The liquid crystal display device according to claim 1. 3. An opposing substrate facing the one surface of the substrate, a liquid crystal sealed between the substrate and the opposing substrate, and an interlayer insulating film provided on the interlayer insulating film. A liquid crystal display device further comprising: an electrode facing the pixel electrode in a direction parallel to the surface. 4. The liquid crystal display device according to claim 1, wherein a cross-sectional shape of at least one of the first portion and the second portion has a substantially triangular shape. 5. The first portion is provided on at least one of the scanning wiring and the signal wiring,
The liquid crystal display device according to claim 1, wherein the dielectric constant of the first portion is smaller than the dielectric constant of the second portion. 6. The liquid crystal display device according to claim 1, wherein the interlayer insulating film has photosensitivity. 7. A step of forming a plurality of switching elements in a matrix on an upper surface of a substrate, and forming scan wirings and signal wirings connected to the switching elements so as to intersect with each other; A step of forming a first interlayer insulating film having a first refractive index on a region of the front surface of the substrate that is shielded when the substrate is irradiated with light from the back surface; and a region other than the region of the front surface of the substrate. A second interlayer insulating film having a second refractive index on the upper surface of the region of FIG. 2 with respect to a plane in which the surface where the first interlayer insulating film and the second interlayer insulating film contact each other is orthogonal to the substrate surface. A liquid crystal display device comprising: a step of forming an inclined surface; and a step of forming a pixel electrode connected to the switching element on the first or second interlayer insulating film. Manufacturing method. 8. The step of forming the pixel electrode includes the step of providing an electrode facing the pixel electrode connected to the switching element on the first or second interlayer insulating film. The manufacturing method described in.