JP2004078204A - Counter substrate for liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a counter substrate for a liquid crystal display panel which does not give rise to the malfunction of the liquid crystal display panel by sufficiently suppressing the temperature rise of the liquid crystal display panel, has high reliability and can deal with a liquid crystal display device of the next generation required to have the line width of light shielding films of ≤2 μm. <P>SOLUTION: The counter substrate is used for the liquid crystal display panel having a liquid crystal layer driven by the voltage impressed between pixel electrodes and counter electrodes arranged to face each other, in which the counter substrate 100 is formed with the light shieldable films 20 in a matrix form on the side facing a driving substrate having the pixel electrodes on a translucent substrate 10. The films 20 have high-reflection films 23 consisting of laminated films of reflection increasing films 22 and reflection films 21 consisting of multilayered dielectric films successively formed on the translucent substrate 10. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a liquid crystal display panel (hereinafter, referred to as a liquid crystal display panel) used as a light valve in a liquid crystal projector or the like, and more specifically, provided in a matrix formed on a counter electrode of the liquid crystal display panel. It relates to a light-shielding film.

2. Description of the Related Art In a liquid crystal display panel used as a light valve in a liquid crystal projector or the like, generally, strong projection light enters from a side of an opposing substrate disposed opposite to a driving substrate (TFT array substrate) with a liquid crystal layer being an electro-optical material interposed therebetween. Is done.
When this strong projection light enters a region for forming a channel as a switching element composed of an a-Si (amorphous silicon) film or a p-Si (polysilicon) film of a TFT on a driving substrate, In the region, a photoelectric current is generated due to a photoelectric conversion effect, thereby deteriorating the transistor characteristics of the TFT. Therefore, in order to suppress this phenomenon, it is common to form a plurality of light-shielding films provided in a matrix form called a black matrix on a counter substrate at a position facing each TFT.

As such a light-shielding film provided in a matrix, in a conventional liquid crystal display device, a metal material such as Cr (chromium) or a material such as resin black in which carbon is dispersed in a photoresist is used. In addition to the light-shielding effect on the a-Si film and the p-Si film described above, it also has functions such as improvement of contrast and prevention of color mixture of color materials in a color filter. However, when such a Cr or resin black is used as a light-shielding film provided in a matrix form in a liquid crystal display panel used as a light valve, since the light reflectance of itself is low, a strong projection light is required. And the temperature of the liquid crystal display panel itself becomes high, which is not preferable.
In order to solve such a problem, a high-reflectance film including a thin film of a metal having a high reflectivity such as Al or Ag is generally used as a light-shielding film provided in a matrix on a counter substrate of a liquid crystal display panel. It has come to be used.

Further, in Japanese Patent Application Laid-Open No. Hei 9-212439 (Patent Document 1), a high-reflectance film made of a metal such as Al is provided on a glass substrate as a light-shielding film provided in a matrix, and a black film is formed thereon. It is disclosed that a low-reflectance film made of resin or Cr oxide is provided.
According to the publication, projection light incident from a side where a light-shielding film provided in a matrix on a glass substrate is not formed is reflected by a film having a high reflectivity, thereby increasing the temperature of a liquid crystal display panel. On the other hand, it is disclosed that stray light generated in a liquid crystal cell is absorbed by a film having a low reflectance to prevent malfunction of a liquid crystal display panel.
Japanese Patent Application Laid-Open No. 9-212439

However, with the recent demand for higher definition and higher luminance of liquid crystal display devices, projection light incident on the opposite substrate has been used with higher intensity. For this reason, malfunctions and deterioration of switching elements and the like due to the temperature rise of the liquid crystal panel are becoming more serious, and even if a conventional high reflection film made of a reflection film such as Al is used, the temperature rise of the liquid crystal panel can be sufficiently increased. It can no longer be suppressed. Further, with the miniaturization of pixels due to the increase in detail of the liquid crystal display device, a pattern in which the line width of the light-shielding film formed in a matrix is 3.5 μm to 2 μm or less is required. In the first place, metal such as Al has weak adhesion to a glass substrate, and there is a concern that peeling of the Al film may occur as the line width of the light-shielding film becomes narrower.
The present invention has been made in order to solve the above-described various problems, and an object of the present invention is to firstly increase the reflectance of a light-shielding film on the side where projected light is incident on a counter substrate. By making the ratio 90% or more, it is possible to sufficiently suppress the temperature rise of the liquid crystal display panel and provide a highly reliable counter substrate for the liquid crystal display panel which does not cause a malfunction of the liquid crystal display panel. An object of the present invention is to provide an opposing substrate for a liquid crystal display panel which does not suffer from film peeling of a light-shielding film, which is compatible with a next-generation liquid crystal display device requiring a line width of a light-shielding film formed in a shape of 2 μm or less. Thirdly, it is an object of the present invention to provide a liquid crystal display panel counter substrate which has a high use efficiency of incident light of the liquid crystal display panel and can obtain a bright image.

The present inventors have proposed that a light-shielding film provided on a counter substrate has a high-reflection film composed of a laminated structure of a reflection-enhancing film and a reflection film that increase reflectivity by using multiple reflection of light, and a liquid crystal display panel. It has been found that the above problem can be solved by increasing the reflectance of the light-shielding film on the side where the projection light is incident on the counter substrate from outside to 90% or more.
That is, the counter substrate for a liquid crystal display panel of the present invention is a counter substrate for a liquid crystal display panel disposed to face a drive substrate having a plurality of pixel electrodes via a liquid crystal layer, wherein the counter substrate is: A light-shielding film provided in a matrix on a side of the light-transmitting substrate facing the drive substrate is formed, and the light-shielding film is formed on the light-transmitting substrate sequentially, A high-refractive-index dielectric thin film made of a material having a high refractive index, and a laminated film having a two-layer structure of a low-refractive-index dielectric thin film made of a material having a relatively low refractive index, or the high-refractive-index dielectric thin film and the The structure has a reflection increasing film formed of a laminated film in which a plurality of low-refractive-index dielectric thin films are alternately stacked, and a high-reflection film formed of a reflection film reflecting incident light incident on the counter substrate.

As described above, the light-shielding film provided on the opposing substrate has a configuration in which the reflection-enhancing film that increases the reflectance by using multiple reflection of light and the high-reflection film having a stacked structure of the reflection film are used. The reflectance of the light-shielding film on the side where the projection light is incident on the counter substrate from outside can be made higher (90% or more) than in the case of a single metal film layer (about 80%). As a result, the absorption of light in the light-shielding film is further reduced, and the temperature rise of the liquid crystal display panel can be sufficiently suppressed even when a high-intensity light source is used. A substrate is obtained. Further, by forming the reflection increasing film formed on the surface of the light-transmitting substrate as the following laminated film (dielectric multilayer film), the adhesion of the light-shielding film to the light-transmitting substrate (for example, a glass substrate) is improved. It becomes possible.
The reflection enhancing film is formed by laminating two or more dielectric thin films having different refractive indexes. For example, a high refractive index dielectric thin film made of a material having a relatively high refractive index and a dielectric thin film having a relatively high refractive index are used. It has a two-layer structure of a low-refractive-index dielectric thin film made of a low material, or a laminated film in which a plurality of the high-refractive-index dielectric thin films and the low-refractive-index dielectric thin films are alternately stacked. . The laminated film reflects incident projection light by utilizing an interference effect due to multiple reflection of light.

Various combinations are possible as materials for the high-refractive-index dielectric thin film and the low-refractive-index dielectric thin film constituting such a dielectric multilayer film. For example, the high-refractive-index dielectric thin film may be made of titanium oxide or niobium oxide. Preferably, the low refractive index dielectric thin film is a combination of silicon oxide. The laminated film of titanium oxide and silicon oxide can form a fine pattern, has excellent adhesion to a light-transmitting substrate, and can prevent peeling of a light-shielding film. In addition, the laminated film of niobium oxide and silicon oxide has the above-mentioned characteristics (a fine pattern can be formed, good adhesion to a light-transmitting substrate, prevention of film peeling of a light-shielding film), and a sputtering target factor. Therefore, there are few pattern defects and the pattern cross-sectional characteristics are good.
The reflection film has a function of reflecting incident light incident on the liquid crystal display panel in a region where the light-shielding film is formed, and is formed of a metal or alloy having a high reflectance. As the reflective film, for example, aluminum, silver, or an alloy containing these elements as a main component is preferable because of its high reflectance in a visible light wavelength region.
In addition, the light-shielding film may include a low-reflection film on the reflection film, which suppresses reflection by return light from the driving substrate side. The low reflection film absorbs stray light generated in the liquid crystal layer and suppresses reflection, thereby preventing malfunction of the liquid crystal display panel. A material having a low reflectance in the visible light region is selected for the low reflection film.

Further, a microlens substrate on which a plurality of microlenses are formed can be provided on the side of the light-transmitting substrate opposite to the side on which the light-shielding film is formed. The microlens substrate is formed, for example, by filling a concave portion formed in the substrate with a high-refractive-index medium, and is provided with a light-shielding film provided with the projection light incident on the opposing substrate from outside the liquid crystal display panel in the matrix shape. Is provided so as to condense light at the position where the opening is formed. That is, the incident light incident on the opposing substrate from the outside of the liquid crystal display panel is narrowed when passing through each microlens, passes through the openings of the light-shielding film provided in a matrix, and further drives the driving substrate. The light passes through the driving substrate without irradiating the switching element formed thereon. As a result, the thermal load due to the incident light that impinges on the light-shielding film is reduced, the reliability of the liquid crystal display panel that does not cause a malfunction is further increased, the light use efficiency is further increased, and a bright image is obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a configuration of a counter substrate according to the first embodiment of the present invention, and FIG. 2 is an enlarged view of a portion A in FIG. FIG. 3 is a longitudinal sectional view showing a liquid crystal display panel using the counter substrate according to the present invention.
First, in FIG. 1, a counter substrate 100 of the present embodiment has a light-shielding film 20 formed in a matrix on a light-transmitting substrate 10. Further, a counter electrode 25 is formed so as to cover one surface of the light-transmitting substrate 10 including the light-shielding film 20.
In the liquid crystal display panel shown in FIG. 3, the opposing substrate 100 of the present embodiment includes a substrate 6 on which a pixel electrode 7 and a switching element 8 such as a TFT for driving the pixel electrode 7 are formed. It is arranged so as to face the substrate 3 with a predetermined space therebetween. By filling the liquid crystal layer 5 in the space between the opposing substrate 100 and the driving substrate 3, the liquid crystal display panel 1 in the form shown in FIG. 3 is obtained. As shown in FIG. 3, dust-proofing is performed on the outside of the opposing substrate 100 and the driving substrate 3 with the liquid crystal layer 5 interposed therebetween so that when foreign matter adheres to the surface of the liquid crystal display panel 1, it is defocused so as not to be projected. Glasses 4a, 4b can be provided. The dustproof glasses 4a, 4b have a configuration in which antireflection films 12a, 12b are formed on glass plates 11a, 11b of quartz glass, crystallized glass, or the like. The antireflection _film, deposited film of _{Al 2 O 3 / ZrO 2 /} MgF 2 is generally used.

The light-shielding film 20 is formed on the driving substrate 3 provided with the projection light incident on the opposing substrate 100 from the outside of the liquid crystal display panel 1 opposed to the opposing substrate 100 via the liquid crystal layer 5. In order to prevent the light from entering the switching element 8 and causing a malfunction, the driving board 3 is provided in a matrix at a position facing the switching element 8.
The configuration of the light-shielding film 20 of the present embodiment will be described in more detail. As shown in an enlarged view of FIG. 2, a high-reflection film 23 and a low-reflection film 24 are sequentially provided on the light-transmitting substrate 10. ing. The high reflection film 23 has a structure in which a reflection increasing film 22 made of a dielectric multilayer film and a reflection film 21 are sequentially formed on the translucent substrate 10. The low-reflection film 24 is made of a material having a lower reflectance than the reflection film 21 in order to suppress reflection by return light from the driving substrate side.

Next, each part of the counter substrate of the present embodiment configured as described above will be described in detail.
First, the high reflection film 23 will be described.
The high-reflection film 23 of the present embodiment has a laminated structure of the reflection-enhancing film 22 and the reflection film 21 made of a dielectric multilayer film as described above.
First, the reflection increasing film 22 will be described.
The reflection increasing film 22 of the present embodiment is formed by laminating two or more dielectric thin films having different refractive indexes. The reflection increasing film 22 has a function of reflecting incident light by an interference effect due to multiple reflection of light.
As such a reflection increasing film 22, a two-layer laminated film of a high-refractive-index dielectric thin film made of a material having a relatively high refractive index and a low-refractive-index dielectric thin film having a relatively low refractive index, or A multilayer laminated film in which high-refractive-index dielectric thin films and low-refractive-index dielectric thin films are alternately laminated can be used.

As the high-refractive-index dielectric thin film, for example, TiO ₂ (n = 2.3 to 2.55), ZrO ₂ (n = 2.05), CeO ₂ (n = 2.2), Ta ₂ O ₅ ( n = 2.1), Nd ₂ O ₃ (n = 2.15), HfO ₂ (n = 1.95), ZnO (n = 2.1), Nb ₂ O ₅ (n = 2.35), ZnS (n = 2.35) and the like. The values in parentheses above indicate the refractive index around the wavelength of 550 nm.
The low refractive index dielectric thin film, for _{example, SiO 2 (n = 1.45~1.46)} , Si 2 O 3 (n = 1.55), MgF 2 (n = 1.38~1.4) And the like. The values in parentheses above indicate the refractive index around the wavelength of 550 nm.
Any of these materials can be used in combination. However, in view of the fact that patterning is easy, a fine (fine) pattern can be formed, and the adhesion with the light-transmitting substrate (for example, a glass substrate) 10, the light-transmitting material can be used. A laminated film of titanium oxide and silicon oxide, particularly a laminated film of TiO ₂ and SiO ₂ , sequentially formed on the substrate 10 is preferable. In general, SiO ₂ has a compressive stress, and TiO ₂ has a tensile stress, so that the stresses of the two layers cancel each other out and the influence of the stress can be reduced. It also has the advantage of being excellent in preventing film peeling due to stress.
From the viewpoint of reducing defects, a laminated film of niobium oxide and silicon oxide (particularly, a laminated film of Nb ₂ O ₅ and SiO ₂ ) sequentially formed on the translucent substrate 10 is preferable. This is because a sputtering target with few defects such as impurities can be obtained, so that defects in the film due to film formation factors can be reduced.
The number of dielectric thin films forming the reflection increasing film 22 is not particularly limited, but is preferably a two-layer structure of a high-refractive-index material and a low-refractive-index material from the viewpoint of ease of film formation and patterning.

Further, when each layer constituting the reflection increasing film 22 is patterned by etching, it is more preferable that the layers can be continuously patterned under the same etching conditions. Further, the patterning of the reflection increasing film 22 can be performed by a lift-off method in addition to the formation by etching.
In order to obtain a desired reflection increasing effect in the high reflection film 23 with respect to the incident light incident from the translucent substrate 10 side, the material, the number of layers and the film thickness of each dielectric thin film in the reflection increasing film 22 are changed. What is necessary is just to determine by the usual optical thin film design method in consideration of a refractive index.
The reflection increasing film 22 can be formed by a normal film forming method such as a sputtering method or an evaporation method.

Next, the reflection film 21 will be described. The reflection film 21 has a function of reflecting incident light incident on the liquid crystal display panel 1 in a region where the light-shielding film 20 is formed. Therefore, the reflection film 21 is formed of a metal or an alloy having a high reflectance. From this point, for the reflective film 21, for example, an Al alloy or an Ag alloy containing a small amount of a metal such as Ni, Ag, Pt, or Al and an additional metal such as Pd is preferably used. Further, elements such as Ti, Cu, and Si may be added to these metals and alloys. The addition of these elements is effective in preventing the generation of pinholes in the light-shielding film. Further, the addition amount of these elements is preferably 0.1 to 5 at% in order to obtain a good pattern. The addition of these elements to the reflective film 21 can be performed, for example, by adding these elements to a sputtering target for forming the reflective film 21.
Among these, metals such as Al and Ag, or alloys containing these as a main component are particularly preferable as the reflective film 21 in terms of high reflectance in visible light.
In particular, when a material containing Al as a main component is used for the reflective film 21, light reflectance is high in a wavelength range of 380 to 700 nm, which is a wavelength range of visible light, and the wavelength dependence of the reflectance is small and uniform reflection is achieved. This is a preferable configuration because it has a good ratio with the low-reflection film 24 described later, and can form a light-shielding film formed in a matrix having a fine pattern.

Further, it is preferable to use a material containing Al as a main component and Ti added to the reflection film 21 because pinholes can be prevented and the adhesion to the low reflection film 24 is good.
The reflective film 21 can be formed by a normal film forming method such as a sputtering method or vapor deposition. In order to obtain a sufficient reflectivity in the high reflection film 23, it is preferable that the reflection film 21 is formed to have a thickness of 300 ° or more.
A preferable reflectance in a region where the light-shielding film 20 is formed with respect to projection light incident on the counter substrate 100 from the outside of the liquid crystal display panel is 90% or more with respect to a commonly used visible light having a wavelength of about 380 to 700 nm. It is more preferably at least 92%, most preferably at least 95%. In the present embodiment, since a laminated film of the reflection increasing film 22 and the reflection film 21 is used as the high reflection film 23, 90% of the incident light entering the counter substrate 100 is formed in the region where the light-shielding film 20 is formed. As described above, the light is reflected at a high reflectance, and the temperature rise of the liquid crystal display panel can be reduced.

Next, the low reflection film 24 will be described.
The low-reflection film 24 provided on the high-reflection film 23 in the light-shielding film 20 absorbs stray light generated in the liquid crystal layer due to return light from the driving substrate side, suppresses reflection, and malfunctions the liquid crystal display panel. Has the function of preventing Therefore, for the low reflection film 24, a material having a lower reflectance than the reflection film 21 for the visible light to be used is selected. It is desirable to select a material having a reflectance in the visible light region of 30% or less, preferably 20% or less, more preferably 10% or less for the low reflection film 24.
As the low reflection film 24, specifically, a metal, a metal oxide, a metal nitride, a metal oxynitride, a high melting point metal silicide such as Ti, Cr, W, Ta, Mo and Pd, for example, WSi (tungsten silicide) Or a black organic dye is preferably used.
It is preferable that the low reflection film 24 forms a uniform thin film by sputtering or vapor deposition. In particular, when a thin film of a metal, a metal oxide, a metal nitride, or a metal oxynitride is used as the low-reflection film 24, the light-shielding property is high and the reflectance can be low even when the film thickness is small. Further, since these materials do not contain an alkali metal which hinders driving of the liquid crystal display panel, they are most suitable as a light shielding film for a liquid crystal display panel.

In particular, when Cr or Ni is used as the above-described metal, chromium oxide or nickel oxide is used as the metal oxide, chromium nitride or nickel nitride is used as the metal nitride, and chromium oxynitride or nickel oxynitride is used as the metal oxynitride, the high reflection film 23 is formed. This is preferable because it can form a light-shielding film provided in a matrix having a fine pattern with good adhesion to the film.
When the low-reflection film 24 is a metal oxide, nitride or oxynitride used for the reflection film 21 of the high-reflection film 23, the low-reflection film 24 is formed at the interface between the low-reflection film 24 and the reflection film 21. The metal oxide, metal nitride or metal oxynitride may be formed so that the composition of the reflective film 21 changes continuously. In this case, the adhesion between the high reflection film 23 and the low reflection film 24 is further improved.
The thickness of the low reflection film 24 is preferably 80 ° or more in order to exhibit the effect of absorbing stray light in the liquid crystal layer. When the total thickness of the high reflection film 23 and the low reflection film 24 is 2000 ° or less, disconnection of the counter electrode 25 formed on the light shielding film 20 can be prevented, and thermal stress applied to the light shielding film 20 can be reduced. This is a preferable configuration without becoming extremely large.
Here, the optical density of the light-shielding film 20 composed of the high reflection film 23 and the low reflection film 24 is 3 or more, preferably 4 or more.

Next, the translucent substrate 10 will be described.
The translucent substrate 10 of the present embodiment needs to be a transparent material that can withstand the thermal effect of strong projection light. As such a translucent substrate 10, a transparent quartz glass substrate, a non-alkali glass substrate, a glass ceramic, or the like is preferably used.
Next, the counter electrode 25 will be described.
The counter electrode 25 is provided for driving the liquid crystal layer 5 together with the pixel electrode 7 on the drive substrate 3 provided to face the counter substrate 100. Therefore, it is sufficient that the light-shielding film 20 is formed at least at a position on the counter substrate 100 corresponding to the pixel electrode 7, but is usually provided so as to cover the entire light-transmitting substrate 10 on which the light-shielding film 20 is formed in a matrix. As such a counter electrode 25, an ITO (indium tin oxide) film or the like is suitably used, and can be formed by a sputtering method or the like.

Next, a method for manufacturing the counter substrate of the present embodiment will be described. The first method for manufacturing a counter substrate is a method for forming a pattern by etching.
First, in the counter substrate 100 of the present embodiment, a reflection increasing film 22, a reflection film 21, and a low reflection film 24 made of a dielectric multilayer film are sequentially formed on the translucent substrate 10. The method for forming these films is as described above.
Next, a predetermined matrix pattern is formed on the reflection increasing film 22, the reflection film 21, and the low reflection film 24.
The pattern is formed by first applying a photosensitive resin (resist) on the low reflection film 24, forming a resist pattern using a photomask having a predetermined pattern, and then sequentially using the resist pattern as a mask. Then, the low-reflection film 24, the reflection film 21, and the reflection-enhancing film 22 are etched to form a light-shielding film 20 having a matrix pattern formed on these layers.
At this time, any of wet etching and dry etching may be used for the etching. For example, when a material mainly composed of Cr is used for the low reflection film 24, dry etching with CCl ₄ or chlorine, or wet etching with a solution containing ceric ammonium nitrate and perchloric acid may be used. it can. When a material containing aluminum as a main component is used for the reflective film 21, dry etching with a mixed gas of CF ₄ and oxygen, CCl ₄ or chlorine, or wet etching with a mixed solution of phosphoric acid and nitric acid is used. Can be. When a laminated film of SiO ₂ or TiO ₂ is used as the reflection increasing film 22, patterning can be performed with a fluorine-based gas such as CF ₄ .
The second method for manufacturing a counter substrate is a method for forming a pattern by lift-off. A photosensitive resin (resist) having etching characteristics different from those of the reflection increasing film 22, the reflection film 21, and the low reflection film 24 made of a dielectric multilayer film is applied on the light transmitting substrate 10, and a photomask having a predetermined pattern is formed. Is used to form a matrix resist pattern. Next, a reflection increasing film 22, a reflection film 21, and a low reflection film 24 made of a dielectric multilayer film are sequentially formed on the translucent substrate 10 with the resist pattern. The method for forming these films is as described above. Next, the resist pattern is stripped with a resist stripper to form a light-shielding film 20 on which a matrix pattern is formed.

Further, the light-shielding film 20 on which the matrix pattern is formed and the counter electrode 25 made of an ITO film or the like are formed by a sputtering method or the like so as to cover the light-transmitting substrate 10.
As described above, the counter substrate 100 of the present embodiment can be obtained.
Further, as shown in FIG. 3 described above, the opposing substrate 100 of the present embodiment is connected to the driving substrate 3 on which the pixel electrodes 7 and the switching elements 8 such as TFTs for driving the pixel electrodes 7 are formed. And the liquid crystal layer 5 is filled in the space between the opposing substrate 100 and the driving substrate 3 to obtain the liquid crystal panel 1.

As described above, in the counter substrate 100 of the present embodiment, the high-reflection film 23 of the light-shielding film 20 has a laminated structure of the reflection-enhancing film 22 and the reflection film 21 made of a dielectric multilayer film. The reflectance of the light-shielding film can be increased to 90% or more as compared with the reflectance (about 80%) of the high reflection film including only the reflection film. As a result, the temperature rise of the liquid crystal display panel can be suppressed, and malfunction due to heat can be effectively prevented. In the counter substrate 100 of the present embodiment, the light-shielding film 20 has good adhesion to the light-transmitting substrate 10 (glass substrate), and the reflection-enhancing film 22 has an oxide film with a small film stress (for example, specifically, By interposing TiO ₂ / SiO ₂ between the reflective film 21 (for example, specifically, Al), even if the line width of the light-shielding film is reduced, film peeling can be prevented. Further, the low-reflection film 24 can absorb stray light in the liquid crystal layer due to return light from the driving substrate side and suppress reflection.

Next, a second embodiment of the present invention will be described.
FIG. 4 is a longitudinal sectional view showing a configuration of a counter substrate 200 according to the second embodiment of the present invention, and FIG. 5 is an enlarged view of a portion B in FIG. In the first embodiment described above, the light-shielding film 20 in which the low-reflection film 24 is formed on the high-reflection film 23 has been described. However, as shown in this embodiment, the light-transmitting substrate 10 The light-shielding film 20 may have only the reflection increasing film 22 made of a dielectric multilayer film and the high reflection film 23 made of the reflection film 21 thereon.
The counter substrate 200 having such a configuration can be manufactured by the same method as that of the above-described first embodiment except that the low reflection film is not formed.

Next, a third embodiment of the present invention will be described.
FIG. 6 is a longitudinal sectional view showing the configuration of the counter substrate according to the third embodiment of the present invention.
The counter substrate 300 of the present embodiment is different from the first or second embodiment in that a plurality of microlenses 35 are formed on the surface of the counter substrate opposite to the side on which the light-shielding film is formed. Thus, the configuration is different from that of the above-described embodiment. Note that the light-transmitting substrate 10 and the light-shielding film 20 are the same as those in the above-described embodiment, and thus description thereof is omitted here. The light-shielding film 20 is composed of the high-reflection film 23 and the low-reflection film 24 as in the first embodiment, but is composed only of the high-reflection film 23 as in the second embodiment. May be.
The opposing substrate 300 with a microlens substrate shown in FIG. 6 includes another translucent substrate 31 and a high-refractive-index medium 33 in addition to the components of the opposing substrate in the above-described first or second embodiment. . On the surface of the light-transmitting substrate 31 that is in contact with the light-transmitting substrate 10, a number of concave portions 32 having a curved bottom surface are provided at positions facing the openings of the light-shielding film provided in a matrix. The microlens substrate having a plurality of microlenses 35 is filled with the high refractive index medium 33.

That is, the high-refractive-index medium 33 is sandwiched between the light-transmitting substrate 10 and the light-transmitting substrate 31 provided with the concave portion 32, and the concave portion 32 and the high-refractive index medium 33 function as convex lenses. Is constituted. The position, the number, and the curved surface of the bottom wall of the concave portion 32 are adjusted so that the focal point of the microlenses 35 is located at the center of the opening of the light-shielding film 20 provided in a matrix.
As the light-transmitting substrate 31, a glass substrate similar to the light-transmitting substrate 10 can be used. As the high-refractive-index medium 33, a resin or the like having a high refractive index for the translucent substrate 31 can be used. Examples of such resins include thiocarbamic acid-s-alkyl ester resins, sulfur-containing urethane resins, sulfur-containing vinyl resins, sulfur-containing polyamides, and sulfur-containing epoxy resins.
The opposing substrate 300 with a microlens substrate can be manufactured as follows.
First, the concave portions 32 having desired positions, numbers, and shapes are formed on one surface of the translucent substrate 31 by a technique such as lithography or etching. Next, the high refractive index medium 33 is filled in the concave portion 32 formed in the light transmitting substrate 31 and bonded to the light transmitting substrate 10. Hereinafter, for example, as in the case of the above-described first embodiment, the reflection increasing film 22 and the reflection film 21 made of a dielectric multilayer film are formed on the surface of the light transmitting substrate 10 where the microlenses 35 are not formed. Is formed, and a low-reflection film 24 is further formed thereon, and these are subjected to patterning in a matrix to form a light-shielding film 20. Further, a counter electrode 25 is formed thereon similarly to the above-described embodiment. Thus, counter substrate 300 of the present embodiment is obtained.

When the opposing substrate 300 with a microlens substrate is used, the incident light incident on the opposing substrate for a liquid crystal display panel first passes through the light-transmitting substrate 31 and then passes through the microlens 35 so that the light beam is narrowed. As a result, most of the incident light passes through the open portions of the light-blocking film 20 provided in a matrix, and further passes through the drive substrate without irradiating the switching elements 8 formed on the drive substrate 3. .
As a result, the thermal load due to incident light and stray light applied to the light-shielding film 20 and the switching elements formed on the drive substrate is reduced, so that a highly reliable counter substrate for a liquid crystal display panel without malfunction is obtained. Can be Further, since the light use efficiency can be improved, a bright and good image can be obtained.
Note that, as the microlens of the present embodiment, not only the microlens in which the high refractive index medium is filled in the substrate having the concave portion described above, but also the incident light is focused on the opening position of the light shielding film provided in a matrix. As long as it is possible, other structures can be used as appropriate.
Hereinafter, the present invention will be described in more detail with reference to Examples. Note that, for convenience of description, reference numerals in the above-described drawings are appropriately used.

The opposing substrate for a liquid crystal display panel of the present embodiment is a light-shielding structure comprising a light-transmitting substrate 10 and a high-reflection film 23 which is a laminated film of a reflection-enhancing film 22 made of a dielectric multilayer film and a reflection film 21 made of a metal film. A conductive film is formed (see FIG. 5).
First, five quartz glass substrates having a thickness of 1.1 mm were prepared as the light-transmitting substrates 10. Next, as the reflection increasing film 22 formed on each translucent substrate 10, a _two- layer film of a TiO ₂ film and a SiO ₂ film is sequentially formed from the translucent substrate side by a sputtering method. Formed. Next, an Al alloy (Ti added) film having a high reflectance in the visible light region was formed as the reflection film 21 on the SiO ₂ film. This reflection film 21 was formed by a sputtering method. The thickness of each layer was 54 nm for the TiO ₂ film, 85 nm for the SiO ₂ film, and 30 nm for the Al alloy film in consideration of the reflectance of the light-shielding film. Thus, the high reflection film 23 which is a laminated film of the reflection enhancement film 22 and the reflection film 21 was formed on the translucent substrate 10.
Next, five opposing substrates were formed on the high-reflection film 23, each having a matrix pattern having a line width different from 3.5 μm, 2.5 μm, 2.0 μm, 1.5 μm, and 1.0 μm. The matrix pattern was formed as follows.

In patterning the high reflection film 23, first, a photosensitive resin (resist) was applied to a thickness of 5000 ° on the Al alloy film as the reflection film 21, and a resist pattern was formed using a photomask.
Next, using this resist pattern as a mask, the Al alloy film was etched using a chlorine-based gas. Subsequently, the SiO ₂ film and the TiO ₂ film serving as the reflection enhancing film 22 were continuously etched using CF ₄ gas. Further, the resist film was dissolved and removed using a resist stripper.
Thus, a light-shielding film composed of the high reflection film 23 formed in a matrix was obtained.
Next, each of the light-transmitting substrates 10 on which the light-shielding film is formed in a matrix is heated to 150 ° C., and the entire surface of the light-transmitting substrate 10 is formed as a counter electrode so as to cover the light-shielding film pattern. Was formed by a sputtering method.
As described above, five counter substrates 200 for a liquid crystal display panel of this example were obtained.

When light of 550 nm in the visible light region was incident on the opposing substrate for the liquid crystal display panel from the translucent substrate 10 side in each example, the reflectance was 92%, and a very high reflectance was obtained. .
Further, with respect to the five opposing substrates having the different line widths described above, the evaluation of the film adhesion was performed by the cellophane adhesive tape peeling test described below.
First, 1000 cycles of high-temperature and low-temperature environmental tests of 120 ° C. (30 minutes) and −55 ° C. (30 minutes) were performed on five counter substrate samples. Thereafter, a peeling test using a cellophane adhesive tape was performed on the matrix-like pattern formed on the counter substrate. As a result, in all of the five opposing substrates having different line widths, separation between the glass substrate and the matrix-like pattern did not occur at all. Therefore, it was confirmed that the opposing substrate of this example can sufficiently cope with the demand for finer pixels.
In the peeling test using a cellophane adhesive tape, a band-shaped tape having a width of 12 to 19 mm with an adhesive tape specified in JISZ 1522 is attached to a matrix-like pattern formed on an opposite substrate. Next, the adhesive tape is strongly pulled so as to be perpendicular to the film surface of the matrix pattern, and the adhesive tape is instantly peeled off. And it is a test for evaluating the peeling state of the matrix pattern at this time.

The counter substrate of the present embodiment is a high-reflection film made of a laminated film of a reflection-enhancing film 22 made of a dielectric multilayer film and a reflection film 21 made of a metal film in a light-shielding film 20 formed on a light-transmitting substrate 10. The second embodiment differs from the first embodiment in that a low-reflection film 24 having a lower reflectance than the metal film is formed on the metal film 23.
First, as in the first embodiment, a reflection increasing film 22 made of a laminated film of a TiO ₂ film and a SiO ₂ film and a reflection film 21 made of an Al alloy are formed on a translucent substrate 10 made of five quartz glasses. Formed.
Next, as the low reflection film 24, a chromium nitride thin film having excellent adhesion to the above-mentioned Al alloy was selected and formed to a thickness of 800 ° on the Al alloy film. The film was formed by a sputtering method using a Cr target while flowing an argon gas containing an oxygen gas.
Thus, a high reflection film 23 and a low reflection film 24, which are a laminated film of the reflection increasing film 22 and the reflection film 21, were formed.

Next, five opposing substrates in which matrix patterns having different line widths of 3.5 μm, 2.5 μm, 2.0 μm, 1.5 μm, and 1.0 μm on these layers were formed. The formation of a matrix pattern was performed as follows.
For patterning, first, a photosensitive resin (resist) was applied to a thickness of 5000 ° on a chromium nitride thin film as the low reflection film 24, and a resist pattern was formed using a photomask.
Next, using the resist pattern as a mask, the chromium nitride film as the low reflection film 24 and the Al alloy film as the reflection film 21 were etched using chlorine gas. Subsequently, in the same manner as in Example 1, the SiO ₂ film and the TiO ₂ film serving as the reflection increasing film 22 were etched, and then the resist film was dissolved and removed.
In this way, a high-reflection layer 23 composed of the reflection-enhancing film 22 and the reflection film 21 and a low-reflection layer 24 were laminated to obtain a light-shielding film 20 formed in a matrix.
Next, in the same manner as in Example 1, an ITO film as a counter electrode was formed on the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 was formed.

As described above, five counter substrates 100 for a liquid crystal display panel of the present example were obtained (see FIGS. 1 and 2).
When light having a wavelength of 550 nm in the visible light region was incident on the opposing substrate for the liquid crystal display panel of the present embodiment from the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 was not formed, the light-shielding film 20 was formed. The reflectance in the formed region was 92%, and a very high reflectance was obtained. On the other hand, when light having a wavelength of 550 nm is incident on the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 is formed, the reflectance in the region where the light-shielding film 20 is formed is about 12%, which is sufficient. It had a low reflectance.
Further, similarly to Example 1, the film adhesion evaluation by the cellophane adhesive tape peeling test was performed on the five opposing substrates having different line widths described above. As a result, in all of the five opposing substrates having different line widths, separation between the glass substrate and the matrix-like pattern did not occur at all. Therefore, it was confirmed that the opposing substrate of this example can sufficiently cope with the demand for finer pixels.

The opposing substrate of the present embodiment is a micro substrate having a large number of microlenses 35 formed at positions corresponding to the openings of the light-shielding film 20 on the side opposite to the side on which the light-shielding film 20 is formed of the light-transmitting substrate 10. The difference from the second embodiment is that the lens substrate 31 is joined (see FIG. 6).
First, a quartz glass substrate having a thickness of 1.1 mm was prepared as a translucent substrate 31 on which a microlens was formed. A plurality of recesses 32 were formed on the glass substrate. When the concave portion 32 is filled with a high-refractive-index resin, the light projected from the outside of the light-transmitting substrate 10 is used as a matrix light-shielding film 20 provided on the light-transmitting substrate 10 in a later step. The position, the number, and the shape are designed so that light is focused at the center of the opening.
Next, a light-transmitting substrate 10 made of quartz glass having a thickness of 1.1 mm is prepared, and the side of the light-transmitting substrate 31 in which the above-described concave portion 32 is formed and the light-transmitting substrate 10 are formed. , A high refractive index resin (thiocarbamic acid-s-alkyl ester resin) was filled and joined. As a result, the concave portion 32 was filled with a high refractive index resin, and a microlens substrate on which a large number of microlenses 35 were formed was obtained.
Next, a light-shielding film 20 provided in a matrix and an ITO film as a counter electrode are formed on the light transmitting substrate 10 of the microlens substrate using the same material and method as in Example 2. Five counter substrates 300 of this example having different line widths of the light-shielding film patterns were obtained.

When light having a wavelength of 550 nm in the visible light region was incident on the opposing substrate for the liquid crystal display panel of the present embodiment from the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 was not formed, the light-shielding film 20 was formed. The reflectance in the formed region was 92%, and a very high reflectance was obtained. On the other hand, when light having a wavelength of 550 nm is incident from the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 is formed, the reflectance in the region where the light-shielding film 20 is formed is 12%, and the reflection is sufficiently low. Had a rate.
Further, similarly to Example 1, the film adhesion evaluation by the cellophane adhesive tape peeling test was performed on the five opposing substrates having different line widths described above. As a result, in all of the five opposing substrates having different line widths, separation between the glass substrate and the matrix-like pattern did not occur at all. Therefore, it was confirmed that the opposing substrate of this example can sufficiently cope with the demand for finer pixels.

In the above-described second embodiment, the reflection increasing film 22 made of a dielectric multilayer film is 55 nm in Nb ₂ O ₅ (refractive index n = 2.35) film and SiO ₂ (refractive index n = 1.46) film by a sputtering method. A counter substrate for a liquid crystal display panel was produced in the same manner as in Example 2 except that the thickness was changed to 85 nm. As described above, when light having a wavelength of 550 nm in the visible light region enters from the surface of the light-transmitting substrate 10 where the light-shielding film 20 is not formed, the reflectance in the region where the light-shielding film 20 is formed is 92%. %, And a very high reflectance was obtained. On the other hand, when light having a wavelength of 550 nm is incident from the surface of the light-transmitting substrate 10 on the side where the light-shielding film 20 is formed, the reflectance in the region where the light-shielding film 20 is formed is about 12%, which is sufficiently low. Had a reflectance.
In addition, the evaluation of the film adhesive force by the cellophane adhesive tape peeling test was performed on the five opposing substrates having different line widths. As a result, in all of the five opposing substrates having different line widths, separation between the glass substrate and the matrix-like pattern did not occur at all. Therefore, it was confirmed that the opposing substrate of this example can sufficiently cope with the demand for finer pixels.

Hereinafter, a comparative example for the above embodiment will be described.
Comparative Example In this comparative example, an Al alloy was directly formed on a light-transmitting substrate without providing a TiO ₂ / SiO ₂ laminated film, which was a reflection-enhancing film in the high-reflection film of Example 2, and a high reflection of the light-shielding film was obtained. Example 2 differs from Example 2 in that it was a film. Other than that, five counter substrates of this comparative example having different line widths of the light-shielding film patterns were produced in the same manner as in Example 2 with the same configuration as in Example 2.
In the counter substrate of this comparative example, when light having a wavelength of 550 nm in the visible light region was incident from the surface of the light-transmitting substrate 10 on the side where the light-shielding film was not formed, the reflection in the region where the light-shielding film 20 was formed was observed. The rate was 84%, which was a lower value than that of Example 2.
Further, after the cellophane adhesive tape peeling test, when a matrix-like pattern formed on a glass substrate having a different line width was confirmed, a film having a line width of 2.0 μm or less was found to have a film crack or peeling. Was confirmed.
As described above, as shown in Examples 1 to 4, by providing a reflection-enhancing film made of a dielectric multilayer film as a highly reflective film in the light-shielding film, the reflectance was increased by 8% as compared with the reflection film alone (comparative example). In addition, a high reflectivity of 90% or more of the light-shielding film can be obtained, and an opposing substrate in which film cracking or film peeling does not occur even when the line width of the matrix pattern is 2 μm or less can be obtained. Was.

(The invention's effect)
As described above in detail, according to the counter substrate for a liquid crystal display panel according to the invention of claim 1, the light-shielding film provided on the light-transmitting substrate of the counter substrate is a reflection-enhancing film made of a dielectric multilayer film. And a reflective film having a laminated structure of a reflective film and a light-shielding film on the side where the projected light is incident on the opposing substrate from the outside of the liquid crystal display panel. 90% or more compared to about 80%), so that light absorption by the light-shielding film can be further reduced, and the temperature rise of the liquid crystal display panel can be sufficiently increased even when a high-intensity light source is used. Thus, a highly reliable counter substrate for a liquid crystal display panel which does not cause a malfunction can be obtained. Further, by providing the dielectric multilayer film, it is possible to improve the adhesion of the light-shielding film to the light-transmitting substrate (for example, a glass substrate).
The reflection increasing film has a two-layer structure of a high refractive index dielectric thin film made of a material having a relatively high refractive index and a low refractive index dielectric thin film made of a material having a relatively low refractive index. Or a configuration in which the high-refractive-index dielectric thin film and the low-refractive-index dielectric thin film are alternately laminated to form a laminated film, so that the projection is performed by utilizing an interference effect due to multiple reflection of light. Light can be efficiently reflected.

According to the second aspect of the present invention, titanium oxide or a combination of niobium oxide and silicon oxide is used as a material of the high refractive index dielectric thin film and the low refractive index dielectric thin film constituting such a reflection increasing film. In addition, the adhesion between the light-shielding film and the light-transmitting substrate is particularly excellent, and peeling of the film due to film stress can be prevented even in a pattern having a line width of 2 μm or less. According to the combination of niobium oxide and silicon oxide, in addition to such effects, film defects due to film formation factors can be reduced.
Further, according to the invention of claim 3, by using aluminum, silver or an alloy containing these as a main component as the reflection film, the area where the light-shielding film is formed for projecting light incident on the liquid crystal display panel is formed. , And has a high reflectance particularly in the wavelength range of visible light used in ordinary liquid crystal display devices.
Also, according to the invention of claim 4, the low-reflection film having a low reflectance for suppressing reflection by return light from the drive substrate side is provided on the reflection film as the light-shielding film. In addition to the effects of the invention, stray light generated in the liquid crystal layer is absorbed by the low reflection layer to suppress reflection, thereby preventing malfunction of the liquid crystal display panel.

Further, according to the invention of claim 5, by providing a microlens substrate on which a plurality of microlenses are formed on a side of the light-transmitting substrate opposite to a side on which the light-shielding film is formed, the outside of the liquid crystal display panel is provided. The incident light incident on the opposing substrate from the substrate is condensed when passing through each microlens, passes through the openings of the light-shielding film provided in a matrix, and further forms a switching element formed on the driving substrate. Since the light passes through the drive substrate without irradiating the light, the thermal burden due to the incident light hitting the light-shielding film is reduced, the reliability of the liquid crystal display panel that does not cause malfunctions is further increased, the light use efficiency is increased, and a bright image is obtained. can get.

FIG. 2 is a longitudinal sectional view of the counter substrate according to the first embodiment of the present invention. It is an enlarged view of the A section in FIG. It is a longitudinal section of the liquid crystal panel using the counter substrate of the present invention. It is a longitudinal section of the counter substrate concerning a 2nd embodiment of the present invention. FIG. 5 is an enlarged view of a portion B in FIG. 4. It is a longitudinal section of the counter substrate concerning a 3rd embodiment of the present invention.

Explanation of reference numerals

REFERENCE SIGNS LIST 1 liquid crystal display panel 3 drive substrate 5 liquid crystal layer 7 pixel electrode 8 switching element 10 light-transmitting substrate 20 light-shielding film 21 reflection film 22 reflection increasing film 23 high reflection film 24 low reflection film 25 counter electrode 31 light-transmitting substrate 35 micro Lens 100, 200 Counter substrate for liquid crystal display panel 300 Counter substrate with micro lens substrate

Claims (5)

A counter substrate for a liquid crystal display panel disposed to face a driving substrate having a plurality of pixel electrodes via a liquid crystal layer,
The opposing substrate is formed with a light-shielding film provided in a matrix on a side of the light-transmitting substrate facing the driving substrate,
The light-shielding film includes a high-refractive-index dielectric thin film formed of a material having a relatively high refractive index and a low-refractive-index dielectric formed of a material having a relatively low refractive index, which are sequentially formed on the translucent substrate. A reflection film comprising a laminated film having a two-layer structure with a body thin film or a laminated film in which a plurality of the high-refractive-index dielectric thin films and the low-refractive-index dielectric thin films are alternately laminated; An opposing substrate for a liquid crystal display panel, comprising a high reflection film comprising a reflection film for reflecting incident light. A the high refractive index dielectric thin film is a titanium oxide (TiO ₂₎ or niobium oxide _(Nb 2 _{O 5),} according to claim 1, wherein the low refractive index dielectric thin film is characterized in that it is a silicon oxide (SiO ₂₎ A counter substrate for a liquid crystal display panel as described in the above. 3. The opposing substrate for a liquid crystal display panel according to claim 1, wherein the reflection film is made of aluminum, silver, or an alloy containing these elements as main components. 4. The opposing substrate for a liquid crystal display panel according to claim 1, wherein the light-shielding film has a low-reflection film on the reflection film for suppressing reflection by return light from a driving substrate side. 5. . A microlens substrate on which a plurality of microlenses are formed is provided on a side of the light-transmitting substrate opposite to the side on which the light-shielding film is formed, and each microlens in the microlens substrate is arranged in the matrix shape. The opposing substrate for a liquid crystal display panel according to any one of claims 1 to 4, wherein the opposing substrate is provided so as to face an opening position of the provided light-shielding film.

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