JP2003043465A - Translucent liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translucent liquid crystal display device having high quality and high reliability, wherein the color purity of panel display in a transmission mode is heightened. SOLUTION: A resin layer 11 having light passing holes H and containing black pigment is formed on a glass substrate 4, the resin layer 11 is coated with a translucent film 10, notched parts P are formed at the translucent film 10, a color filter 9 is formed on the resin layer 11 coated with the translucent film 10 and an overcoat later 8, a transparent electrode 5 and an alignment layer 6 are further formed thereon. A transparent electrode 5 and an alignment layer 6 are formed on the other substrate 4. The glass substrates are stuck to each other via a liquid crystal layer 7 consisting of a chiral nematic liquid crystal twisted at an angle of 200-260 deg..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transflective liquid crystal display device.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been used not only for small or medium-sized portable information terminals and notebook computers, but also for large and high-definition monitors. Furthermore, the technology of a reflective liquid crystal display device that does not use a backlight has been developed, and is excellent in thinness, light weight, and low power consumption.

The reflection type liquid crystal display device is of a scattering reflection type in which an uneven light reflection layer is formed on the inner surface of a substrate arranged at the rear, but it is possible to effectively use ambient light by not using a backlight. Are used for.

Further, a semi-transmissive liquid crystal display device has also been developed in which a semi-transmissive film which is a half mirror is formed in place of the light reflection layer, a backlight is provided, and a reflective mode or a transmissive mode is selectively used.

According to this semi-transmissive liquid crystal display device, it is used as a reflective device by external illumination such as sunlight or a fluorescent lamp, or as a transmissive device by mounting a backlight as internal illumination. A semi-permeable membrane is used to combine both functions (Japanese Patent Laid-Open No. 8-292).
See No. 413).

Further, it has been proposed to use a semi-transmissive film for the same purpose also in an active matrix type semi-transmissive liquid crystal display device (see Japanese Patent Laid-Open No. 7-318929).

Further, when the semi-transmissive film of such a half mirror is used, there is a problem that it is difficult to improve both functions of reflectance and transmittance, and in order to solve this problem, a light transmission hole is provided. A semi-transmissive liquid crystal display device using the provided reflective film as the semi-transmissive film has also been proposed (see Japanese Patent No. 2878231).

[0008]

However, in the transflective liquid crystal display device, the incident light passes through the color filter twice in the reflection mode, whereas the incident light passes only once in the transmission mode. Since the thickness of the color filter (coloring layer) is constant in both the reflective area and the transmissive area, the color purity of the panel display in the transmissive mode deteriorates as compared with that in the reflective mode, resulting in a lighter hue. Was there.

Therefore, the present invention has been completed in view of the above, and an object thereof is to provide a high-quality and highly reliable semi-transmissive liquid crystal display device in which the color purity of the panel display in the transmissive mode is enhanced. It is in.

[0010]

A semi-transmissive liquid crystal display device according to the present invention has a light-shielding layer having a light passage hole formed on a substrate,
A light-semitransmissive film made of a metal film is provided on the light-shielding layer,
A color filter is coated on the light-semitransmissive film so as to fill the light-transmitting holes, and a transparent electrode and an alignment layer are sequentially laminated on the color filter, and a transparent electrode on the transparent substrate. And nematic liquid crystal are interposed between the other member formed by sequentially stacking and the alignment layer, and pixels are arranged in a matrix.

In another semi-transmissive liquid crystal display device of the present invention, a large number of light-shielding resin convex portions are randomly arranged on a substrate and a convex arrangement group in which light passage holes are formed is arranged. A light semi-transmissive film formed of a metal film is provided on the group, a color filter is coated on the light semi-transmissive film so as to fill the light transmissive holes, and a transparent electrode and an alignment layer are further provided on the color filter. Pixels are arranged in a matrix with a nematic liquid crystal interposed between one member formed by sequentially laminating a transparent electrode and the other member formed by sequentially laminating a transparent electrode and an alignment layer on a transparent substrate. Characterize.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings.

Example 1 A transflective liquid crystal display device for color display will be described with reference to FIG. The figure is a schematic cross-sectional view of a transflective liquid crystal display device.

First, one member will be described. 4 is a glass substrate, and a resin layer 11 containing a black pigment as the light shielding layer having a light passage hole H is formed on the glass substrate 4, and on this resin layer 11. Is covered with a semi-transmissive film 10, which is the light semi-transmissive film. Notches P are formed in the semi-permeable film 10, and the notches P are formed in a lattice pattern,
Each color filter has a width at the boundary, and when combined with the resin layer 11 therebelow, it becomes a light-shielding member arranged between each pixel.

The semi-transmissive film 10 has, for example, a SiO ₂ layer of 50 to 300 Å in order to improve its adhesiveness.
It may be formed underneath depending on its thickness.

The semi-transmissive film 10 is provided with a light-shielding property by a metal film such as chromium, aluminum, Al alloy (AlNd, AlCMg, etc.), silver, Ag alloy (AgPd, AgPdCu, AgCuAu, etc.). A notch P and a light passage hole H are formed in the notch P.
The light passage hole H is formed by a photolithography technique using a photolithography mask corresponding to the shape. That is, a photosensitive resist is applied to the surface of the film on which the metal film is formed, exposed using a photolithographic mask, and then, development, etching, and peeling steps are performed to form the film.

Then, the color filter 9 arranged for each pixel is formed on the resin layer 11 coated with the semi-transmissive film 10 as described above. Specifically, the color filter 9 is coated on the semi-transmissive film 10 so as to fill the light transmission hole H of the resin layer 11, but the portion corresponding to the cutout P is not covered with the color filter 9. By doing so, the boundary of each pixel is formed in a grid pattern.

The color filter 9 is formed by a pigment dispersion method, that is, by applying a photosensitive resist prepared in advance with pigments (red, green, blue) on a substrate and photolithography.

Further, an overcoat layer 8 made of an acrylic resin and a plurality of transparent electrodes 5 made of ITO arranged in parallel in stripes are formed. An alignment film 6 made of a polyimide resin rubbed in a certain direction is formed on the transparent electrode 5.

Although the alignment film 6 is formed directly on the transparent electrode 5, an insulating film made of resin or SiO ₂ may be interposed between the alignment film 6 and the transparent electrode 5. Also, the overcoat layer 8 may not be provided.

As for the other member, a plurality of transparent electrodes 5 made of ITO arranged in parallel in a stripe pattern on the glass substrate 4 and an alignment film 6 made of polyimide resin rubbed in a certain direction are sequentially formed. Transparent electrode 5 and alignment film 6
An insulating layer made of a resin or SiO ₂ may be interposed between and.

Then, the one member and the other member having such a constitution are bonded by a seal member (not shown) via the liquid crystal 7 made of chiral nematic liquid crystal twisted at an angle of, for example, 200 to 260 °. Also,
A large number of spacers (not shown) are arranged between both members to keep the thickness of the liquid crystal 7 constant.

Further, a front scattering film 28, a first retardation film 3 made of polycarbonate or the like, a second retardation film 2 and an iodine type polarizing plate 1 are successively formed on the outside of the glass substrate 4 of the other member, and one member is formed. The retardation film 12 and the iodine-based polarizing plate 1 are sequentially formed on the outside of the glass substrate 4. These parts are attached by applying an adhesive material made of an acrylic material. There is a forward scattering film 28 (for example, IDS: manufactured by Sumitomo Chemical Co., Ltd.), a transparent resin containing a scattering agent is applied on a transparent substrate film having a thickness of 80 μm, and a scattering layer having a thickness of 8 μm is laminated on the substrate. There is.

As this transparent substrate film, a film made of TAC (triacetyl cellulose) having no birefringence is used, and the surface of the scattering layer is flattened so that backscattering due to unevenness does not occur. Inside the scattering layer, fine particles having a refractive index different from that of the medium are used as a scattering agent, and the fine particles are uniformly dispersed in the transparent medium.

In the liquid crystal display device having the above structure, incident light from external illumination such as sunlight or a fluorescent lamp is polarized plate 1, second retardation film 2, first retardation film 3, forward scattering film 28 and glass substrate. 4, passes through the liquid crystal 7, the color filter 9 and the like to reach the semi-transmissive film 10, is reflected by the metal film of the semi-transmissive film 10, and the reflected light is emitted in the reflection mode.

In this liquid crystal display device, a transmissive display mode is set by disposing a backlight on the back surface of the one member.

[Method of forming one member] Next, referring to FIG. 3 and FIG.
A method of forming the one member will be described with reference to the process chart shown in FIG.
Each step of (a) to (h) is sequentially performed, and each step will be described below.

First, each step shown in FIG. 3 will be described in detail.

Step (a) A photosensitive resist (Black resist) prepared by a black pigment is dispersed on a glass substrate by a pigment dispersion method.
It is applied to a thickness of 1.0 ± 0.5 μm, and then formed on a predetermined portion by photolithography. As this photosensitive resist, for example, a resist material manufactured by Nippon Steel Chemical Co., Ltd .: V259-
There is BKIS-272X.

In the present example, a photomask as shown in FIG. 15 is used, for example. Reference numeral 24 is a light-shielding portion made of chromium metal, and this light-shielding portion 24 is patterned on a glass substrate. This photomask corresponds to a negative resist, and the portion where the photosensitive resist is removed by development corresponds to the light passage hole H.

Then, by changing the area ratio of the light passage hole H and the resist portion in each pixel, the ratio of the reflection area and the transmission area can be set as required. In this example, the area ratio between the light passage hole and the resist portion is 6
It is formed at 0:40.

In this step, the resin layer 11 having the light passage hole H is formed on the glass substrate 4.

Step (b) On the substrate obtained in the step (a), aluminum metal (Al), Al alloy (AlNd, AlC) is formed as a metal film.
Mg etc.), silver (Ag), Ag alloy (AgPd, AgPd
A metal reflection film 16 made of Cu, AgCuAu, AgRuCu, or the like) is formed. This metal reflection film 16 is
l or Al alloy, 1000 Å, A
If it is formed of g and Ag alloy, the film is formed with a film thickness of about 1500 Å. In addition, in order to improve the adhesion between the resist and the metal film, SiO ₂ or IT is used as the base of the metal film.
Oxides such as O, In ₂ O ₃ and TiO ₂ may be formed to a film thickness of about 100Å.

Step (c) Patterning is performed on the metal film. For that purpose, a predetermined portion is removed from the metal film by using a photolithography technique.

FIG. 16 is a plan view of a photomask used in this photolithography technique. Reference numeral 24 is a light-shielding portion made of chromium metal. The light-shielding portion 24 is patterned on a glass substrate. This photomask corresponds to a positive type resist. Here, the portion where the metal film is removed by etching is between the light passage hole H and each pixel (notch P).

The color filter 9 is formed by the pigment dispersion method in each of the steps (d) to (f) shown in FIG.
In the figure, R, G, and B represent red, green, and blue color filters (colored layers), respectively.

(D) Step As Red (red) formation, a photosensitive resist prepared by using a red pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed on a predetermined portion by photolithography.

(E) Step As green (green) formation, a photosensitive resist prepared with a green pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed on a predetermined portion by photolithography.

(F) Step As Blue (blue) formation, a photosensitive resist prepared by using a blue pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed on a predetermined portion by photolithography.

The order of the steps (d) to (f) may be changed.

(G) Step In this step, the overcoat layer 8 is formed,
Apply acrylic resin to a thickness of 2.2 ± 0.2 μm.

Step (h) As a transparent electrode formation, an ITO film is formed in a thickness of 1000 to 3700Å
It is formed with a film thickness of. In order to improve the adhesion between the overcoat layer 8 and the ITO film, an intermediate layer such as SiO ₂ may be formed as the base of the ITO film.

As a result of the above steps, FIG.
A color filter substrate as shown in is obtained. This figure is a plan view showing an enlarged schematic view of a main part of each pixel, 21 is a light passage part corresponding to the light transmission hole H of the resin layer 11, 22 is a reflection part, and 23 is between pixels. .

The thickness of the black resist is set to 1 μm.
m, and each color filter (R
Assuming that the film thickness of the ed resist, the green resist, and the blue resist is 1 μm, the color filters (Red resist, Green) in the portion where the black resist is not present.
The film thickness of the n-resist and the blue resist) is 2 μm, the film thickness of the color filter in the reflection region corresponding to the reflection part 22 is 1 μm, and the film thickness of the color filter in the transmission region corresponding to the light passage part 11 is 2 μm.

In the liquid crystal display device having the color filter substrate having such a structure, the behavior of incident light is shown in FIG.
The reflection mode and the transmission mode will be described. In addition,
In the figure, a circle indicates that the incident light is valid for the reflection mode or the transmission mode, and a cross indicates that it is invalid.

Reflection Mode The incident light from the upper side of the liquid crystal display device will be separately described, and the way in which the light rays travel will be described in order.

Is the light incident between the pixels of the color filter, and since a reflection film is not formed in this portion, B
It is absorbed by the black resist and there is no reflected light. Therefore, there is no reflected light from between the pixels of the color filter, and thus high contrast can be obtained.

Light is incident on the reflection area (metal reflection film), and this portion is reflected by the metal reflection film to be reflected light.

Is the light incident on the transmission region (light passage hole). Since no reflective film is formed on this portion, it passes through the light passage hole as it is and there is no reflected light.

Transmission Mode The incidence of light from the lower side of the liquid crystal display device by the backlight will be separately described, and the way in which the light rays travel will be described in order.

The light incident between the pixels of the color filter is absorbed by the black resist because the black resist is formed in this portion, and there is no transmitted light. Further, since there is no transmitted light between the pixels of the color filter, high contrast can be obtained.

Light is incident on the reflection area (metal reflection film), which is also absorbed by the black resist and has no transmitted light.

Light is incident on the transmission region (light passage hole), and since this portion does not have a reflection film formed, it passes through the light passage hole as it is and becomes transmitted light.

As is clear from the above optical path, the reflected light in the reflection mode passes through the color filter of 1 μm twice, and the transmitted light in the transmission mode passes through the color filter of 2 μm.
Pass twice.

Next, the results of measuring the optical characteristics of the liquid crystal display device having such a structure will be described below.

In the reflection mode, as shown in FIG. 10A, when the light (C light source) is incident from the obliquely upper 15 ° of the liquid crystal display device to drive the liquid crystal display device (white display, black display). (Display, red display, green display, blue display), the reflectance of vertically reflected light, the contrast, and the color gamut area were measured. The C light source is a (standard white light source having chromaticity (x, y) = (0.310, 0.316)).

In the transmissive mode, as shown in FIG. 10B, when light (C light source) is incident from the lower part of the liquid crystal display device to drive the liquid crystal display device (white display, black display,
The transmittance, contrast, and color gamut area of transmitted light in the vertical direction (red display, green display, blue display) were measured.

FIG. 19 shows a definition diagram of the color gamut area. The color gamut area is an area surrounding each RGB chromaticity point. The larger the area, the higher the color reproducibility and the higher the color purity of the panel display.

In measuring the optical characteristics of the semi-transmissive liquid crystal display device of the present invention, the conventional semi-transmissive liquid crystal display device was similarly measured. This conventional transflective liquid crystal display device is an external scattering system using a transflective film, and its configuration is shown in FIG. The same parts as those of the device shown in FIG. 1 are designated by the same reference numerals.

According to the transflective liquid crystal display device of the present invention,
A semi-transmissive film 10 in which a resin layer 11 having a light passage hole H is formed on a glass substrate 4 and a cutout P is provided on the resin layer 11.
And a color filter 9 for each pixel
However, instead of this, the semi-transmissive film 14 is formed on the glass substrate 4, and the color filter 9 arranged for each pixel is formed thereon. The semi-permeable film 14 is made of the same material as the semi-permeable film 10.

The optical characteristics of the transflective liquid crystal display device of the present invention and the conventional transflective liquid crystal display device were measured, and the results shown in Tables 1 and 2 were obtained.

[0062]

[Table 1]

[0063]

[Table 2]

In Table 1, Ron and Ton are the reflectance and the transmittance when white is displayed, respectively.
Are the reflectance and transmittance for black display respectively, and CR
(Contrast) indicates Ron / Roff and Ton / Toff.

As is clear from these tables, in the reflection mode, the conventional example and the device of the present invention have almost the same characteristics, but according to the transmission mode, the device of the present invention is more transparent than the conventional example. Although the rate is low, on the other hand, the color gamut area (the area of the triangle formed by connecting the R, G, and B chromaticities) has improved 2.16 times from 0.69 to 1.49.

Here, the OD value of the black resist will be described. Table 3 shows the contrast of the transmission mode when the OD value of the black resist is changed.

[0067]

[Table 3]

As is clear from this table, when the OD value is lowered, the contrast is lowered, but when the OD value is 1.7 or less, the contrast is rapidly lowered. Therefore, the OD value of the black resist is 1.7 or more,
It is preferable to use one having an OD value of 2.0 or more.

(Example 2) Another transflective liquid crystal display device for color display will be described with reference to FIG. This figure is a schematic cross-sectional view of the semi-transmissive liquid crystal display device, and the same parts as those in the semi-transmissive liquid crystal display device shown in FIG.

In the apparatus of this example, a convex array group is provided instead of the resin layer 11, and the forward scattering film 28 is provided.
It is a structure that does not form.

In the following, a concrete configuration will be described. In the one member, a large number of resin projections containing a black pigment, which are the light-shielding resin projections, are randomly arranged on the glass substrate 4 to form the light passage holes H. Is formed on the convex array group 13, and the semi-transmissive film 10 that is the light semi-transmissive film is formed on the convex array group 13.
And a cutout portion P is formed in the semipermeable membrane 10.

A color filter 9 is coated on the semi-transmissive film 10 so as to fill the light transmission holes H of the convex array group 13. Further, an overcoat layer 8 made of an acrylic resin and a plurality of transparent electrodes 5 made of ITO arranged in parallel in stripes are formed, and an alignment film 6 made of a polyimide resin rubbed in a certain direction is formed.

An insulating film made of resin or SiO ₂ may be interposed between the alignment film 6 and the transparent electrode 5, and the overcoat layer 8 may not be provided.

As for the other member, the transparent electrode 5 and the alignment film 6 are sequentially formed on the glass substrate 4 similarly to (Example 1), but a resin or SiO ₂ is formed between the transparent electrode 5 and the alignment film 6. May be interposed.

Then, one member and the other member having such a constitution are bonded by a seal member (not shown) via the liquid crystal 7 made of chiral nematic liquid crystal twisted at an angle of, for example, 200 to 260 °, and A large number of spacers (not shown) are arranged between the two members to keep the thickness of the liquid crystal 7 constant.

Further, a first retardation film 3 made of polycarbonate or the like, a second retardation film 2 and an iodine type polarizing plate 1 are sequentially formed on the outside of the glass substrate 4 of the other member, and the glass substrate 4 of one member is The retardation film 12 and the iodine-based polarizing plate 1 are sequentially formed on the outer side as well.

In the liquid crystal display device having the above structure, incident light from external illumination such as sunlight or a fluorescent lamp passes through the polarizing plate 1, the second retardation film 2, the first retardation film 3 and the glass substrate 4, The light reaches the semi-transmissive film 10 through the liquid crystal 7, the color filter 9, and the like, is reflected while being scattered by the metal film of the semi-transmissive film 10, and the reflected light is emitted as a reflection mode.

Thus, in the liquid crystal display device of the present invention, by not using the forward scattering layer, the conventional problem of back scattering is solved, and as a result, the brightness when the reflective display mode is OFF is reduced. , The contrast has improved. Then, in this liquid crystal display device, a transmissive display mode is set by providing a backlight.

[Method of Forming One Side Member] Next, referring to FIGS.
A method of forming the one member will be described with reference to the process chart shown in FIG.

First, as shown in FIG.
Through the steps (e), the convex array group 13 having the light passage holes H is formed. Each of these steps will be described below.

Step (a) A photosensitive resist (positive resist) 17 prepared with a black pigment is applied on the transparent glass substrate 4 (thickness 0.5 mm) to a thickness of 1.5 ± 0.5 μm. Next, 105 ±
Pre-bake at 10 ° C for 3 minutes. This resist is JSR
For example, there is a resist material made of PC405G containing a black pigment.

(B) Process Using the photomask 19, proximity exposure is performed with an exposure amount of 80 mj / cm ² . FIG. 14 is a plan view of the photomask 19. A large number of circular light-shielding portions 24 made of Cr or the like are formed on a glass substrate in a random arrangement to form a light-shielding pattern.

Of the photosensitive resists 17 shown in FIG. 7b,
The upper portion 18 has a composition in which the resist is easily dissolved in the developing solution when exposed. That is, the resist 17 has an upper portion 18 and other portions.

(C) Step Next, using the photomask 20, proximity exposure is performed with an exposure amount of 300 mj / cm ² .

As shown in the plan view of FIG. 15, this photomask 20 uses a light shielding pattern made of Cr or the like as the light shielding portion 24. Also in this example, by changing the area ratio of the light passage hole and the resist portion in the pixel, the ratio of the reflection region and the transmission region can be freely changed. In this example, light passage hole: resist portion = 60: Set to 40.

According to the combination of the steps (b) and (c), the exposure amount for forming the slits is larger than the exposure amount for forming the uneven layer which is the convex array group 13. By changing the development speed of the uneven part and the slit part, the unevenness is formed by one development, and at the same time, the slit part is developed up to the glass substrate.

(D) Step Next, development was performed to form an uneven portion and a slit portion. The uneven portion uses the proximity light of proximity exposure to obtain a smooth curved surface with the pattern corners removed after development, and the slit portion completely removes the resist up to the glass substrate. PD523AD (0.238 ± 0.1
%) (Manufactured by JSR) and developed for 50 ± 10 seconds (20 ° C.). By obtaining such a smooth curved surface, the deviation of the inclination angle distribution of the uneven shape is reduced.

Step (e) Further, the entire surface is exposed to remove the unreacted components of the photosensitive resin. In this step, post-baking 220 ± 10
The resin is cured by carrying out the temperature (15 minutes).

As described above, the convex array group 13 having the light passage holes H is formed by each step.

Continuing, one member is formed according to the process charts shown in FIGS.

As shown in these figures, (a) to (g)
Each step is sequentially performed.

Step (a) The metal film 16 is formed on the convex array group 13 having the light passage holes H.
As aluminum metal (Al), Al alloy (AlN
d, AlCMg, etc.), silver (Ag), Ag alloy (AgP
d, AgPdCu, AgCuAu, AgRuCu, etc.) is formed. This metal reflective film 16
Is 1000 when formed from such Al or Al alloy.
Å If it is made of Ag, Ag alloy, 15
The film is formed with a film thickness of about 00Å. Further, in order to improve the adhesion between the resist and the metal film, SiO is formed on the base of the metal film.
An oxide such as ₂ , ITO, In ₂ O ₃ , or TiO ₂ may be formed to a film thickness of about 100 Å.

Step (b) As the metal film patterning, the semi-transmissive film 10 is formed by using photolithography to remove the metal film except for a predetermined portion.

FIG. 15 shows a photomask used for this. As shown in the figure, 24 is a light-shielding portion made of chromium metal, and this light-shielding portion 24 is patterned on a glass substrate. This photomask corresponds to a positive type resist. Here, the portion where the metal film is removed by etching is between the light passage hole H and each pixel (notch P).

The color filter 9 is formed by a conventionally known method in each of the following steps (c) to (e).

(C) Step As Red formation, a photosensitive resist prepared by using a red pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed on a predetermined portion by photolithography.

(D) Step As green formation, a photosensitive resist prepared with a green pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed by photolithography at a predetermined portion.

(E) Step As Blue formation, a photosensitive resist prepared by using a blue pigment is applied to a thickness of 1.0 ± 0.1 μm, and then formed on a predetermined portion by photolithography.

The order of the steps (c) to (e) may be changed.

(F) Step The overcoat layer 8 is formed. 2.2 acrylic resin
Apply with a thickness of ± 0.2 μm.

(G) Step As a transparent electrode, an ITO film is formed with a film thickness of 1000 to 3700Å. Here, in order to improve the adhesion between the overcoat layer and the ITO film, an intermediate layer such as SiO ₂ may be formed on the base of the ITO film.

By passing through the above steps, FIG.
A color filter substrate as shown in is obtained. This figure is a plan view showing an enlarged schematic view of a main part of each pixel. Reference numeral 21 denotes a light passage portion corresponding to the light transmission hole H of the convex array group 13.
Reference numeral 2 is a reflecting portion, and 23 is between pixels.

Then, the thickness of the black resist is set to 1 μm.
m, and each color filter (R
Assuming that the film thickness of the ed resist, the green resist, and the blue resist is 1 μm, the color filters (Red resist, Green) in the portion where the black resist is not present.
The film thickness of the n-resist and the blue resist) is 2 μm, the film thickness of the color filter in the reflection area corresponding to the reflection portion 22 is 1 μm, and the film thickness of the color filter in the transmission area corresponding to the light passing portion 11 is 2 μm.

In the liquid crystal display device shown in FIG. 5 having the color filter substrate having such a structure, the behavior of incident light will be described with reference to FIG. 6 in the reflection mode and the transmission mode.

Reflection Mode The incident light is separated and the way in which the light ray travels will be described in order. Is the light incident between the pixels of the color filter,
Since the reflective film is not formed, it is absorbed by the black concave / convex resist and there is no reflected light. Therefore, there is no reflected light from the pixels of the color filter, and high contrast can be obtained.

The light incident on the reflection area (metal reflection film) is reflected by the metal reflection film to be reflected light.

Is the light incident on the transmission region (light passage hole). Since no reflective film is formed on this part,
It passes through the light passage hole as it is, and there is no reflected light.

Transmission Mode The incidence of light from the lower side of the liquid crystal display device by the backlight will be described separately, and the way in which the light rays travel will be described in order.

Light incident between the pixels of the color filter is absorbed by the black resist because the black concave / convex resist is formed, and there is no transmitted light. Since there is no transmitted light between the pixels of the color filter, high contrast can be obtained.

Reference numeral B denotes the light incident on the reflection area (metal reflection film). Since the black resist is formed, B
It is absorbed by the lac uneven resist and there is no transmitted light.

The light is incident on the transmission region (light passage hole). Since no reflective film is formed on this portion, it passes through the light passage hole as it is and becomes transmitted light.

Here, the reflected light in the reflection mode passes through the color filter of 1 μm twice, and the transmitted light in the transmission mode passes through the color filter of 2 μm once.

Next, the optical characteristics of each of these liquid crystal display devices were measured. In the reflection mode, when light (C light source) is incident from above the liquid crystal display device to drive the liquid crystal display device (white display, black display, red display, green display,
The reflectance, contrast, and color gamut area of the reflected light (displayed in blue) were measured.

In the transmissive mode, when light (C light source) is incident from the lower part of the liquid crystal display device to drive the liquid crystal display device (white display, black display, red display, green display, blue display). The transmittance of the transmitted light, the contrast, and the color gamut area were measured.

FIG. 19 shows a definition diagram of the color gamut area. The color gamut area indicates the area surrounding each RGB chromaticity point. The larger the area, the higher the color reproducibility, and the panel display with high color purity becomes possible.

Tables 4 and 5 are comparisons of the optical characteristics of the transflective liquid crystal display device of the present invention and the conventional transflective liquid crystal display device.

According to this conventional apparatus, a convex array group 15 is formed on the glass substrate 4 in which a large number of resin-made convex sections containing black pigment are randomly arranged, and the convex array group 15 is formed.
The semi-transmissive film 14 is coated thereon, and the color filter 9 is further formed on the semi-transmissive film 14.

[0118]

[Table 4]

[0119]

[Table 5]

In Table 4, Ron and Ton are the reflectance and transmittance for white display, and Roff and Toff are the reflectance and transmittance for black display. CR (contrast) is Ron / R
Indicates off and Ton / Toff.

As is clear from the results shown in Tables 4 and 5, in the reflection mode, the conventional example and the device of the present invention have almost the same characteristics. In the transparent mode, the device of the present invention has a lower transmittance than the conventional example,
The color gamut area has improved 2.14 times from 0.85 to 1.82.

Here, as for the OD value of the black resist, as described in (Example 1), similarly, the OD value =
It is preferable to use one having an OD value of 2.0 or more, preferably 1.7 or more.

Next, another method for forming one member of the liquid crystal display device shown in (Example 2) will be described with reference to (Example 3), (Example 4) and (Example 5).

(Example 3) FIG. 17 shows a method for forming one member, in which steps (a) to (d) are sequentially performed.

Step (a) A photosensitive resist 17 (negative resist) prepared by a black pigment is formed on the transparent glass substrate 4 (thickness 0.5 mm) to a thickness of
Apply at 1.5 ± 0.5 μm. Next, pre-bake at 105 ± 10 ° C for 3 minutes. This resist includes V259-BKIS-272X which is a resist material manufactured by Nippon Steel Chemical.

Process (b) Proximity exposure is performed with a photomask at an exposure dose of 400 mj / cm ² . As the photomask, as shown in FIG. 18, by forming a pattern of a metal film with Cr or the like, a portion through which light passes is shielded. And
An innumerable circular pattern formed by combining light-shielding patterns formed in a random arrangement is used. In the pixel, the ratio of the reflection area and the transmission area can be freely changed by changing the area ratio of the light passage hole and the other area, but in this example, the light passage hole: the other portion = 60: 40. To form.

Step (c) Development was carried out to form an uneven portion and at the same time, a light passage hole was formed. The concave and convex portions utilize the light wraparound of the proximity exposure, and after development, the corners of the pattern are removed to obtain a smooth curved surface, and the light passing hole portions are completely resist-removed by the development. . 2401ID (manufactured by Nippon Steel Chemical Co., Ltd.) was used as a developing solution, and development was performed for 50 ± 10 seconds (20 ° C.).

(D) Step Post-baking was performed at 240 ± 20 ° C. for 30 minutes to cure the uneven resin.

Through the above steps, the uneven resin having the light passage holes is formed.

(Example 4) FIG. 20 shows another method for forming one member, which sequentially goes through the steps (a) to (d).

Step (a) The thickness of the photosensitive resist 17 (negative resist) prepared by the black pigment on the transparent glass substrate 4 (thickness 0.5 mm).
Apply at 1.5 ± 0.5 μm. Next, pre-bake at 105 ± 10 ° C for 3 minutes.

Step (b) By using the mold 26 in which a desired strip shape is formed, the substrate obtained in the step (a) is pressed to expose the entire surface with an exposure amount of 100 mj / cm ² . An uneven shape can be obtained.

Process (c) Proximity exposure is performed with a photomask at an exposure dose of 400 mj / cm ² . As the photomask, as shown in FIG. 21, a photomask is used which is shielded from light except for a portion which allows light to pass therethrough.

By changing the area ratio of the light passage hole portion and the other portion in the pixel, the ratio of the reflection region and the transmission region can be freely changed. In this example,
Light passing hole part: other part = 60: 40.

Step (c) Development was performed to form light passage holes. PD523A is the developer
Using D (manufactured by JSR), development was performed for 50 ± 10 seconds (20 ° C.).

Step (d) Post-baking was performed at 240 ± 20 ° C. for 30 minutes to cure the uneven resin.

Through the above steps, an uneven resin having light passage holes is formed.

(Example 5) FIG. 25 shows still another method of forming one member, in which steps (a) to (d) are sequentially performed.

Step (a) A photosensitive resist 17 (negative resist) prepared by a black pigment is formed on the transparent glass substrate 4 (thickness 0.5 mm) to a thickness of
Apply at 1.5 ± 0.5 μm. Next, pre-bake at 105 ± 10 ° C for 3 minutes.

Step (b) Using the concavo-convex transfer film 29 having a desired strip shape, the substrate obtained in step (a) is pressed.

Step (c) With the concavo-convex transfer film 29 attached, proximity exposure is performed using the photomask 26 at an exposure amount of 400 mj / cm ² . As this photomask, as shown in FIG. 21, a photomask made of Cr metal or the like, which is shielded except for a portion through which light passes, is used.

By changing the area ratio of the light passage hole portion and the other portion in the pixel, the ratio of the reflection region and the transmission region can be freely changed. In this example,
Light passing hole part: other part = 60: 40.

Step (c) After the uneven transfer film 29 was peeled off, development was carried out to form a light passage hole. PD523AD (manufactured by JSR) was used as a developing solution, and development was performed for 50 ± 10 seconds (20 ° C.).

Step (d) Post-baking was performed at 240 ± 20 ° C. for 30 minutes to cure the uneven resin.

In the step (a), instead of applying the photosensitive resist, the uneven transfer film to which the photosensitive resist has been applied in advance may be transferred to the glass substrate. Through the above steps, the uneven resin having the light passage holes is formed.

(Slit Shape of Light Passing Hole) Next, the present inventor examined the preferable structure relating to the slit shape of the light passing hole, and the following results were obtained.

FIG. 23 is a schematic view in which a large number of rectangular parallelepiped light passage holes are formed in one pixel, and the vertical direction of the light passage holes: a.
When the chromaticity of the transmitted light passing through the light passage hole was measured when the width: b was kept constant at 20 μm and the depth: c was changed, the results shown in Table 6 were obtained.

The evaluation in this measurement is divided into four types, ⊚ when the chromaticity improving effect is particularly large, ○ when the chromaticity improving effect is large, and Δ when the chromaticity improving effect is small. The cross indicates that there is no chromaticity improvement effect. The method of measuring the chromaticity is the same as the method of measuring the optical characteristics in the transmission mode described above.

[0149]

[Table 6]

As is clear from this table, the chromaticity is improved by setting the depth of the light passage hole to 0.3 μm ≦ c, and preferably 0.5 μm ≦ c.

Further, in the structure shown in FIG. 23, the depth: c of the light passage hole is kept constant at 1 μm, and the size of the length: a and the width: b is changed in various ways, and the light passage hole has a different size. When the degree of depression was measured, the results shown in Table 7 were obtained.

The evaluation of this measurement is divided into four types, ⊚ indicates that the depression of the light passage hole is particularly small, ○ indicates that the depression of the light passage hole is small, and Δ indicates the depression of the light passage hole. When it is large, the cross indicates that the depression of the light passage hole is particularly large.

[0153]

[Table 7]

As is clear from this table, when a and b are almost equal and are roughly square, a and b ≦ 50 μ
By setting m, the depression of the light passage hole becomes small,
Preferably, a and b ≦ 30 μm.

Further, in the case of a rectangle of a ≠ b, by setting a or b ≦ 30 μm, the depression of the light passing hole portion becomes small, preferably a, b ≦ 20 μm.

Next, the inventors of the present invention have confirmed by experiments a preferred example in which a large number of cylindrical light passage holes are formed in one pixel as shown in the schematic diagram of FIG.

In the structure of FIG. 24, the radius of the light passage hole:
When the size of r was kept constant at 10 μm and the depth: c was changed, the chromaticity improvement effect of the transmitted light passing through the light passage hole was measured, and the results shown in Table 8 were obtained. Also here, when the ◎ mark has a particularly large effect of improving chromaticity,
A circle indicates that the chromaticity improving effect is large, a triangle indicates that the chromaticity improving effect is small, and a cross indicates that there is no chromaticity improving effect.

[0158]

[Table 8]

As is clear from the table, the effect of improving chromaticity can be seen by setting the depth of the light passage hole to 0.3 μm ≦ c, and preferably 0.5 μm ≦ c.

Further, in the structure of FIG. 24, when the depth: c of the light passage hole was kept constant at 1 μm and the size of the radius: r was changed, the degree of depression of the light passage hole was measured.
The results shown in are obtained. Again, ◎ indicates that the light passage hole recess is particularly small, ○ indicates that the light passage hole recess is small, and △ indicates that the light passage hole recess is large.
The cross mark indicates that the depression of the light passage hole is particularly large.

[0161]

[Table 9]

As is clear from this table, r ≦ 25 μm
By setting the above, the depression of the light passage hole becomes small, and preferably r ≦ 15 μm.

The present invention is not limited to the above embodiment, and various modifications and improvements may be made without departing from the scope of the present invention. For example, although the resin layer 11 containing the black pigment is formed as the light shielding layer having the light passage hole H, a metal such as chromium oxide (the surface is blackened by the oxide film) may be used instead.

[0164]

As described above, according to the transflective liquid crystal display device of the present invention, a light-shielding layer having a light passage hole is formed on a substrate, and a light-semitransmissive layer formed of a metal film is formed on the light-shielding layer. A film is provided, and a color filter is coated on the light-semitransmissive film so as to fill the light-transmitting holes, and one member obtained by sequentially stacking a transparent electrode and an alignment layer on the color filter is used, or A large number of light-shielding resin-made convex portions are randomly arranged on the substrate to arrange a convex array group in which light passage holes are formed, and a light-semitransmissive film formed of a metal film is provided on the convex array group. A simple structure is obtained by using a one-side member in which a color filter is coated on the light-semitransmissive film so as to fill the light-transmitting holes, and a transparent electrode and an alignment layer are sequentially laminated on the color filter. In the transmission mode, the color purity of the panel display is the reflection mode It could provide a high-performance semi-transmissive liquid crystal display device which is improved to position become equal.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal display device of the present invention.

FIG. 2 is an enlarged view of a color filter substrate according to the present invention.

3A, 3B, 3C, 3D, 3E, 3F, 3G, and 3G are process diagrams showing a method for manufacturing a color filter substrate according to the present invention.

4A to 4D are process drawings showing a method for producing a color filter substrate according to the present invention.

FIG. 5 is a schematic cross-sectional view of another liquid crystal display device of the present invention.

FIG. 6 is an enlarged view of another color filter substrate according to the present invention.

7A, 7B, 7C, 7D, 7E, 7F, 7G, 7G, 7G, 7H, 7I, 7I, 9I, 9I, 9I, 9I, 9I, 9I, 9E, 9I, 9Ie, 9Ie, 9I, 9I, 9I, 9I, 9I, 9I, 9I, 9F, 9Iees 6es 7es 7es 7es 7es 7es 7es 7es 7es 7es 8es 7es 8es 7 and 8es arees are diagrams showing steps of a method of manufacturing another color filter substrate according to the present invention.

8A, 8B, 8C, 8D, 8E, 8F, 8G, 8H, 8H, 8I, 8I, 8H, 8H, 8I, 8I, 8I, 8H, 8H, 8I, 8I and 8E are process drawings showing a method of manufacturing another color filter substrate according to the present invention.

9A to 9E are process drawings showing a method of manufacturing another color filter substrate according to the present invention.

10 (a) and 10 (b) are explanatory views showing a measuring method for evaluating optical characteristics.

FIG. 11 is a cross-sectional view of a conventional liquid crystal display device.

FIG. 12 is an enlarged view of each pixel according to the color filter substrate of the present invention.

FIG. 13 is an enlarged view of each pixel according to another color filter substrate of the present invention.

FIG. 14 is a plan view of a photomask for forming a convex array group.

FIG. 15 is a plan view of a photomask for forming a light passage hole of black resin.

FIG. 16 is a plan view of a photomask for forming a light passage hole of a metal film.

FIG. 17A, FIG. 17B, FIG. 17C, and FIG. 17D are process drawings showing a method of forming a convex array group with light passage holes.

FIG. 18 is a plan view of a photomask for forming a convex array group with light passage holes.

FIG. 19 is an explanatory diagram showing the definition of color gamut area.

20 (a), (b), (c), (d), and (e) are process diagrams for forming a convex array group with light passage holes.

FIG. 21 is a plan view of a photomask.

FIG. 22 is a cross-sectional view of another conventional liquid crystal display device.

FIG. 23 is a schematic view of one pixel having a rectangular parallelepiped light passage hole.

FIG. 24 is a schematic view of one pixel having a cylindrical light passage hole.

25A, 25B, 25C, 25D, 25E, 25F, 25F, 25F, 25G, 25H, 25H, 25H, 25H, 25H, 25H, 25H, 25H, 25H, 25F, 25F, 25F, 25F, 25F and 25F are process drawings showing a method for manufacturing another color filter substrate according to the present invention.

[Explanation of symbols]

1 ... Polarizing plate 2 ... Second retardation film 3 ... First retardation film 4 ... Glass substrate 5: Transparent electrode 6 ... Alignment film 7: Liquid crystal composed of chiral nematic liquid crystal 9 ... Color filter 11 ... Resin layer containing black pigment 10 ... Semi-permeable membrane 28 ... Forward scattering film 29 ... Uneven transfer film P ... Notch H: Light passage hole

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Claims (2)

[Claims] 1. A light-shielding layer having light passage holes is formed on a substrate, a light-semitransmissive film formed of a metal film is provided on the light-shielding layer, and a color filter is provided on the light-semitransmissive film. One member that is coated so as to fill the holes, and further that a transparent electrode and an alignment layer are sequentially laminated on the color filter,
A semi-transmissive liquid crystal display device in which pixels are arranged in a matrix with a nematic liquid crystal interposed between another member formed by sequentially laminating a transparent electrode and an alignment layer on a transparent substrate. 2. A plurality of light-shielding resin-made convex portions are randomly arranged on a substrate to arrange a convex array group in which light passage holes are formed, and an optical half formed by a metal film on the convex array group. Providing a permeable membrane,
A color filter is coated on the light-semitransmissive film so as to fill the light-transmitting holes, and a transparent electrode and an alignment layer are sequentially laminated on the color filter, and a transparent electrode on the transparent substrate. A semi-transmissive liquid crystal display device in which pixels are arranged in a matrix with a nematic liquid crystal interposed between the other member and an alignment layer which are sequentially laminated.