JP2002268054A - Liquid crystal display device and method for manufacturing liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device which can display an image of high quality even when functioning as a reflection type or a transmission type irrespective of the brightness of use environment and a manufacturing method for the liquid crystal display device. SOLUTION: This device has a reflection part PR and a transmission part PT in a single pixel area P to display an image by selectively reflecting external light with the reflection part PR in a well-lighted place or selectively transmitting the back light projected by a back light unit 30 with the transmission part PT in a dark place. A color filter CFR of the reflection part PR is formed of the same material having the same film thickness as a color filter CFT of the transmission part PT and has different spectral wavelength characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a reflective portion for displaying an image by reflecting external light in one pixel region and displaying an image by transmitting backlight light. The present invention relates to a transflective color liquid crystal display device having a transmissive portion.

[0002]

2. Description of the Related Art In general, liquid crystal display devices are applied to various uses such as personal computers, various monitors, car navigation systems, and TVs. Above all, the reflection type liquid crystal display device has been applied to a display for a portable device such as a mobile PC, taking advantage of low power consumption, thinness and light weight since a backlight unit is not required.

A reflection type liquid crystal display device has a built-in light reflection layer inside and displays an image by reflecting light incident from the outside. From such a principle, in the conventional reflective liquid crystal display device, when the use environment is dark, the display screen becomes dark, and the displayed image is difficult to see. In particular, it cannot be used at all in the dark.

In order to solve these problems, transflective liquid crystal display devices have been put to practical use. In this transflective liquid crystal display device, a backlight unit is arranged on a back surface of a liquid crystal display panel, and is used as a transmissive liquid crystal display element in a dark environment, and is used as a reflective liquid crystal display element in a bright environment. .

In this transflective liquid crystal display device, the built-in reflection layer is a transflective layer, that is, a half mirror, or one pixel region is divided into a transmissive portion and a reflective portion to provide a certain amount of backlight light. Is transmitted. Regardless of the system, the display performance is ensured regardless of the brightness under the usage environment by reflecting the light from the outside and transmitting a certain percentage of the light from the backlight at the same time. It is.

[0006] Such a transflective liquid crystal display device can also perform color display by incorporating a color filter.

In such a transflective liquid crystal display device, when functioning as a reflective type, external light passes twice through a color filter provided on a reflective electrode. Therefore, the color filter needs to have a spectral wavelength characteristic such that a desired color can be obtained when external light passes twice. In this case, the light used is external light, and the light intensity cannot be freely controlled.

In addition, the transmittance of the entire device is not sufficient due to other components such as a polarizing plate.
In order to keep the brightness of the display screen as high as possible (keeping the transmittance high), the spectral wavelength characteristics of the color filters are designed to be so light that sufficient coloring cannot be obtained when external light passes once. I have no choice. When used as a reflection type, a color filter having such a spectral wavelength characteristic has to be used in consideration of display brightness.

When the transflective type liquid crystal display device functions as a transmissive type, the backlight light passes through the color filter only once. Therefore, the color filter needs to have a spectral wavelength characteristic such that a desired color can be obtained when the backlight passes only once. That is, when functioning as a transmission type, the spectral wavelength characteristic of the color filter is the spectral wavelength characteristic when the light passes through the color filter once, that is, the spectral wavelength characteristic of the color filter itself.

When a color filter having an optimum spectral wavelength characteristic when used as a reflection type is used as a transmission type, an extremely light color density results. Conversely, when a color filter having an optimum spectral wavelength characteristic when functioning as a transmissive type is used for a reflective type, the luminance is extremely reduced.

Conventionally, in order to solve such a problem,
Color filters may be disposed on the array substrate side and the counter substrate side, respectively, and the color filter on the array substrate side or the counter substrate side corresponding to the reflection portion may be replaced with a transparent resin.
However, in this method, a color filter is required on each of the array substrate side and the opposing substrate side, and in addition to an increase in the number of components, the manufacturing process becomes complicated, which may lead to an increase in product cost. In addition, dividing the color filter on the counter substrate side into regions corresponding to pixels requires high precision in alignment between the color filter on the counter substrate and the color filter on the array substrate, which also lowers the manufacturing yield. There is a problem that results in an increase in the cost of the product.

[0012]

As described above, in a transflective color liquid crystal display device, the brightness of a display image is significantly reduced when functioning as a reflection type, or the display image is deteriorated when functioning as a transmission type. Only the optical characteristics of whether the luminance is extremely low can be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to achieve high quality even when functioning as a reflection type and a transmission type regardless of the brightness under the use environment. An object of the present invention is to provide a liquid crystal display device capable of displaying an image and a method for manufacturing the liquid crystal display device.

[0014]

In order to solve the above problems and achieve the object, a liquid crystal display device according to claim 1 comprises a liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates;
A backlight unit for illuminating the liquid crystal display panel, wherein one pixel region formed on one of the substrates has a first color filter layer and a reflective electrode for reflecting external light. And a transmissive unit that includes a second color filter layer and a transmissive electrode and transmits backlight light from the backlight unit, wherein the first color filter layer and the second color filter layer are:
It is formed of the same material having the same thickness and has different optical characteristics.

According to a seventh aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: a liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates; and a backlight unit for illuminating the liquid crystal display panel. One pixel region formed on the substrate includes a first color filter layer and a reflection type electrode, and a reflection unit for reflecting external light, and a second color filter layer and a transmission type electrode, and a backlight from the backlight unit. A method of manufacturing a liquid crystal display device having a light-transmitting portion, wherein the first color filter layer is formed on the reflective electrode by a photolithography step, and at the same time, the light is reflected on the first color filter layer. A plurality of openings penetrating to the mold electrode are formed.

According to a eighth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: a liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates; and a backlight unit for illuminating the liquid crystal display panel. One pixel region formed on the substrate includes a first color filter layer and a reflection type electrode, and a reflection unit for reflecting external light, and a second color filter layer and a transmission type electrode, and a backlight from the backlight unit. A method of manufacturing a liquid crystal display device having a light-transmitting portion, wherein the first color filter layer and the second color filter layer are formed by an inkjet method;
The first color filter layer and the second color filter layer are different in the content of the coloring agent contained in each.

According to a ninth aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, comprising: a liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates; and a backlight unit for illuminating the liquid crystal display panel. One pixel region formed on the substrate includes a first color filter layer and a reflection type electrode, and a reflection unit for reflecting external light, and a second color filter layer and a transmission type electrode, and a backlight from the backlight unit. A method for manufacturing a liquid crystal display device having a light transmitting portion, wherein the first portion is formed by a photolithography process.
A color filter layer and the second color filter layer are formed, and the first color filter layer is different in film thickness from the second color filter layer by exposing through a halftone mask. .

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a liquid crystal display device of the present invention and a method of manufacturing the liquid crystal display device will be described with reference to the drawings.

As shown in FIG. 1 and FIG. 2, a liquid crystal display device according to an embodiment of the present invention is arranged such that an array substrate (first substrate) 100 is opposed to the array substrate 100 at a predetermined interval. Opposing substrate (second substrate) 200,
A liquid crystal display panel (liquid crystal cell) 10 having a liquid crystal layer 300 containing a liquid crystal composition held in a predetermined gap between the array substrate 100 and the counter substrate 200 is provided. The liquid crystal display device further includes a backlight unit 30 that illuminates the liquid crystal display panel 10 from the back.

In such a liquid crystal display panel 10,
A display area 102 for displaying an image includes an outer edge sealing member 106 for bonding the array substrate 100 and the counter substrate 200.
Are formed in a region surrounded by. Display area 1
A peripheral area 104 having a wiring, a driving circuit, a power supply wiring, and the like drawn out from inside 02 is formed in a region outside the outer edge seal member 106.

In the display area 102, the array substrate 10
0 is m arranged in a matrix as shown in FIG.
xn pixel electrodes 151, m scanning lines Y1 to Ym formed along the row direction of these pixel electrodes 151, and n signal lines X1 to Xn formed along the column direction of these pixel electrodes 151 , And m × n pixel electrodes 151, and m × n thin film transistors, ie, pixel TFTs 121, arranged as switching elements near intersections of the scanning lines Y1 to Ym and the signal lines X1 to Xn.

In the peripheral region 104, the array substrate 100 includes a scanning line driving circuit 18 for driving the scanning lines Y1 to Ym and a signal line driving circuit 1 for driving the signal lines X1 to Xn.
9 and the like. Each of the scanning line driving circuit 18 and the signal line driving circuit 19 is configured by a complementary circuit including an n-channel thin film transistor and a p-channel thin film transistor.

As shown in FIG. 2, the liquid crystal capacitance CL is formed by the pixel electrode 151, the counter electrode 204, and the liquid crystal layer 300 sandwiched between these electrodes. The auxiliary capacitance Cs is formed electrically in parallel with the liquid crystal capacitance CL. The auxiliary capacitance Cs is formed by a pair of electrodes opposed to each other via an insulating layer, that is, an auxiliary capacitance electrode 61 having the same potential as the pixel electrode 151 and an auxiliary capacitance line 52 set to a predetermined potential. . The auxiliary capacitance electrode 61 is formed of a polysilicon thin film and is in contact with the pixel electrode 151. The auxiliary capacitance line 52 is formed of the same material as the scanning line Y integrated with the gate electrode 114.

The array substrate 100 and the counter substrate 2
No. 00 is adhered by a sealing material 106 in a state where a predetermined gap is formed by a columnar spacer (not shown). The liquid crystal layer 300 is sealed in a predetermined gap formed between the array substrate 100 and the counter substrate 200.

As shown in FIGS. 3 and 4, the pixel area P
Generally corresponds to a region defined by the scanning lines Y and the signal lines X provided on the array substrate 100. The one pixel region P includes a reflector PR for displaying an image by selectively reflecting external light from the outside, and a backlight unit 3.
And a transmission portion PT for displaying an image by selectively transmitting backlight light from 0.

Each of the pixel regions P includes a color filter CF colored in three primary colors in order to realize color display.
Is provided. In this embodiment, for example, color filters CF colored red (R), green (G), and blue (B) are provided in the red pixel region, the green pixel region, and the blue pixel region, respectively. This color filter CF
For example, it is formed of a resin in which pigments of each color component are dispersed.

The backlight unit 30 shown in FIG.
Are arranged on the back surface of the array substrate 100 in the liquid crystal display panel 10. This backlight unit 30
Is a light guide plate having a wedge-shaped cross section, a light source disposed on one side of the light guide plate, a reflection plate surrounding the light source, an optical sheet such as a prism sheet disposed between the light guide plate and the array substrate, and the like. It is configured to have.

The reflection part PR is disposed on a transparent insulating substrate, for example, a glass substrate 101 having a thickness of 0.7 mm.
The bump 161 includes a bump 161 formed of a transparent resin such as an acrylic resin resist, and a reflective electrode 151R formed on the bump 161 and formed of a metal reflective film such as aluminum or silver. A color filter CFR is provided on the reflective electrode 151R.

The transmitting portion PT is formed by a color filter CFT disposed on the glass substrate 101 and a transparent conductive member formed of a transparent conductive member such as indium-tin-oxide, ie, ITO, provided on the color filter CFT. And an electrode 151T. This transmission electrode 1
As shown in FIGS. 3 and 4, 51T may be arranged in the entire one pixel region including the reflection part PR and the transmission part PT, or may be arranged only in the transmission part PT.

The reflection electrode 151R and the transmission electrode 151T
Functions as a pixel electrode 151 electrically connected to the source electrode of the TFT 121. That is, the reflective electrode 151R and the transmissive electrode 151T are electrically conducted and are kept at the same potential.

The thickness d1 of the color filter CFR of the reflection part PR is equal to the thickness d2 of the color filter CFT of the transmission part PT.
Is almost equivalent to This color filter CF is provided for each of red (R), green (G), and blue (B) as shown in FIG.
Are formed of materials having spectral wavelength characteristics as shown in FIG.

The thickness of the color filter CF is 1 μm or less, which is sufficiently smaller than the interval (cell gap: 10 μm or less) formed between the array substrate 100 and the counter substrate 200. For this reason, the color filter CF does not become a factor that disturbs the cell gap.

The TFT 121 has a portion protruding from the scanning line Y as a gate electrode, and has a semiconductor film formed of an amorphous silicon film, a polysilicon film, or the like laminated on the gate electrode via a gate insulating film. TFT12
One drain electrode is electrically connected to the pixel electrode 151. The source electrode of the TFT 121 is electrically connected to the signal line X. In the example shown in FIGS. 3 and 4, the TFT 121 is disposed below the bump 161 near the intersection of the signal line X and the scanning line Y.

The reflection electrode 151R as the pixel electrode 151
Is in contact with the drain electrode via a contact hole formed in the bump 161 on the drain electrode of the TFT 121, and is electrically connected. Also, the pixel electrode 1
The transmission electrode 151T as 51 is in contact with the drain electrode via the bump 161 on the drain electrode of the TFT 121 and the contact hole formed in the color filter CFR, and is electrically connected.

The surface of the transmission electrode 151T is
0, and is covered with an alignment film 141 for aligning the liquid crystal composition 300 interposed therebetween.

In the display area 102, the counter substrate 200
As shown in FIG. 4, a counter electrode 204 is provided on a transparent insulating substrate, for example, a glass substrate 201 having a thickness of 0.7 mm. The counter electrode 204 is formed of a transparent conductive member that forms a potential difference with the pixel electrode 151, for example, ITO. The surface of the counter electrode 204 is covered with an alignment film 205 for aligning the liquid crystal composition 300 interposed between the counter electrode 204 and the array substrate 100. The counter electrode 204 is set to a reference potential so as to face the plurality of pixel electrodes 151.

The electrode transfer material disposed around the substrate, ie, silver paste as a transfer, is
The counter electrode 204 is provided to supply a voltage from 0 to the counter substrate 200, and the counter electrode 204 is driven by the counter electrode driving circuit 20 connected via a transfer.

On the outer surface of the glass substrate 101 of the array substrate 100, a λ / 4 wavelength plate 181 and a polarizing plate 183 are provided. On the outer surface of the glass substrate 201 of the counter substrate 200, a diffusion plate 207, a λ / 4 wavelength plate 209, and a polarizing plate 211 are provided. For the polarizing surfaces of the polarizing plates 183 and 211, an optimal direction is selected according to the display mode of the liquid crystal display device, the twist angle of the liquid crystal composition, and the like.

The thickness of the liquid crystal layer between which the liquid crystal composition 300 is sandwiched, that is, the gap having a predetermined width formed between the array substrate 100 and the counter substrate 200 is determined by the wiring patterns of the signal lines X and the scanning lines Y, TFT 121, pixel electrode 15
1. Secured by spacers arranged in non-pixel areas such as peripheral picture frames.

As described above, the thickness of the liquid crystal layer 300 is made different between the reflection part PR and the transmission part PT by providing the bump 161 on the reflection part PR. This is to make the two optical configurations coincide with each other.
This is because the optical path length of the reflection portion PR that reciprocates in 0 (that is, transmits twice) is set to half of the transmission portion PT.

For example, when using the TN mode of 90 ° twist, the actual thickness of the liquid crystal layer 300 (cell gap)
Where d is the birefringence of the liquid crystal layer 300 and Δn is the retardation value Δnd at the reflection part PR and about 0.46 μm at the transmission part PT. Specifically, when a nematic liquid crystal having a birefringence Δn of 0.09 is used, as shown in FIG. 4, the thickness d of the liquid crystal layer 300 is about 2.3 μm at the reflection part PR, Transmission part PT
Should be about 5.1 μm. Therefore, the reflection part PR
The thickness of the bump 161 provided on the substrate may be about 2.8 μm.

By the way, this liquid crystal display device, ie, 1
In a transflective liquid crystal display device having a reflective portion PR and a transmissive portion PT in a pixel region, as shown in FIG. 4, the color filters CF provided over the reflective portion PR and the transmissive portion PT have the same film thickness and the same thickness. Is formed of the material. Moreover, the color filter CF in the reflection part PR
R differs from the color filter CFT in the transmission part PT in optical characteristics, that is, spectral wavelength characteristics.

That is, the color filter CF provided over the reflection part PR and the transmission part PT is formed of a material having a spectral wavelength characteristic as shown in FIG. 5, as described above.

In the transmission part PT, the backlight light generated from the backlight unit 30 enters from the lower surface side of the array substrate 100 and passes through the color filter CFT by one.
The light is transmitted only once, and further passes through the liquid crystal layer 300 and is selectively emitted to the counter substrate 200 side.

In this transmission part PT, the backlight light only passes through the color filter CFT once,
At this time, the luminance of the light emitted from the counter substrate 200 side is the spectral wavelength characteristic itself of the material forming the color filter CF, and is a luminance according to the spectral wavelength characteristic as shown in FIG.

On the other hand, in the reflection portion PR, the opposite substrate 2
External light incident from the 00 side passes through the liquid crystal layer 300, passes through the color filter CFR, is further reflected by the reflection electrode 151R, and is again reflected by the color filter CFR.
After passing through the liquid crystal layer 300,
It is selectively emitted from the side.

In this reflecting section PR, external light passes through the color filter CFT twice. Therefore, normally, the luminance of the light emitted from the counter substrate 200 side is the square of the transmittance in the spectral wavelength characteristic of the material forming the color filter CFR. That is, the reflection part PR
Is obtained by squaring the spectral wavelength characteristic shown in FIG. 5, and has the characteristic shown in FIG.

The spectral wavelength characteristic of the color filter CF is determined by the following equation.
When the setting is such that the optimum luminance is obtained when T is transmitted only once, the optimum luminance cannot be obtained in the reflection part PR, and the luminance of the display image is significantly reduced.

Therefore, the color filter CFR in the reflection part PR is replaced with the color filter CFT in the transmission part PT.
While forming the same material and the same film thickness with the reflection part PR
It is necessary to improve the spectral wavelength characteristics of the color filter CFR in the above. That is, it is necessary to set the spectral wavelength characteristics of the color filter CFR in the reflection part PR so that an optimum luminance can be obtained when the external light transmits the color filter CFR twice.

For this reason, in this transflective liquid crystal display device, as shown in FIG. 3, the color filter CFR in the reflection part PR has a plurality of minute openings 400 penetrating to the reflection electrode 151R in the plane thereof. are doing. The diameter of the opening 400 and the number of the openings 400 can be set as appropriate.

As described above, by forming a large number of minute openings 400 in the color filter CFR in the reflection section PR, the color filter is formed by the ratio of the total area of the opening 400 to the total area of the remaining color filters CFR. The spectral wavelength characteristics of the CFR can be adjusted.

Therefore, by setting the ratio of the total area of the opening to the total area of the remaining color filters CFR to an optimum condition according to the diameter of the opening 400 and the number of the openings 400, the external light can be filtered by the color filter. It is possible to obtain an optimum spectral wavelength characteristic such that an optimum luminance is obtained when the light passes through the CFR twice.

Next, a method of manufacturing this liquid crystal display device will be described.

That is, a glass substrate 1 having a thickness of 0.7 mm
01, a metal film and an insulating film are repeatedly formed and patterned, and the scanning line Y including the gate electrode of the TFT 121 and the auxiliary capacitance electrode 52, the gate insulating film, the semiconductor film of the TFT 121, the signal line X, and the source electrode of the TFT 121 are formed. And a drain electrode and the like.

Subsequently, on the entire surface of the glass substrate 101,
A transparent UV-curable acrylic resin resist is applied using a spinner and dried. Thereafter, the acrylic resin resist is exposed using a photomask having a predetermined pattern shape corresponding to the reflection portion PR of each pixel region P, and then developed with a predetermined developing solution. Then, by baking, the bump 161 having a film thickness of 2.8 μm is formed. At this time, a contact hole penetrating to the drain electrode of the TFT 121 is formed in the bump 161 at the same time.

Subsequently, an aluminum thin film is formed on the entire surface of the glass substrate 101 by a sputtering method. At this time, the contact hole of the bump 161 is also filled with aluminum, and the drain electrode of the TFT 121 and the pixel electrode 1 are filled.
51 is electrically connected. After that, this aluminum thin film is patterned into a predetermined pixel electrode shape so as to remain on the bump 161. Thus, on the bump 161,
A reflection electrode, that is, a pixel electrode 151R is formed.

Subsequently, a color filter CF is formed on the entire surface of the glass substrate 101 by a photolithography process. That is, an ultraviolet curable acrylic resin resist in which a red pigment is dispersed is applied to a predetermined thickness on the entire surface of the glass substrate 101 using a spinner. At this time, the acrylic resin resist is formed such that the film thickness at the reflection part PR having the bump 161 is substantially the same as the film thickness at the transmission part PT without the bump 161.

After drying the acrylic resin resist, the resist is exposed using a photomask having a shape corresponding to the red pixel region, and then developed with a predetermined developing solution. Then, by firing, a red color filter CF having a predetermined thickness is formed in the transmission part PT and the reflection part PR.

Similarly, a green color filter CF in the green pixel region and a green color filter CF in the blue pixel region by using an ultraviolet-curable acrylic resin resist in which a green pigment is dispersed and an ultraviolet-curable acrylic resin resist in which a blue pigment is dispersed. The blue color filters CF are respectively formed.

At the same time, in the photolithography process of the color filter CF, a plurality of minute openings 400 penetrating to the reflection electrode 151R are formed in the color filter CFR in the reflection portion PR so as to obtain optimum spectral wavelength characteristics. Thereby, in the photolithography process when forming the color filters CF of each color, the opening 400 can be formed simultaneously with the patterning of the color filters CF. For this reason, it is possible to adjust the spectral wavelength characteristics of the color filters CFR in the reflection unit PR to the optimum conditions without increasing the number of processes.

At the same time, T is applied to the color filter CF.
A contact hole penetrating to the drain electrode of the FT 121 is formed.

Subsequently, the entire surface of the glass substrate 101
An O thin film is formed by a sputtering method. At this time,
The contact hole of the color filter CF is also filled with ITO, and the drain electrode of the TFT 121 and the pixel electrode 151 are electrically connected. After that, the ITO thin film is patterned into a predetermined pixel electrode shape so as to remain in the entire one pixel region P. Thus, the transmission electrode, that is, the pixel electrode 15
Form 1T.

Subsequently, an alignment film material is applied to the entire surface of the substrate, and a rubbing process is performed to form an alignment film 141.

On the other hand, a glass substrate 201 having a thickness of 0.7 mm
A counter electrode 204 and an alignment film 205 are formed thereon, and a counter substrate 200 is formed.

Subsequently, the sealing material 106 is printed along the periphery of the alignment film 205 of the counter substrate 200 except for the liquid crystal injection port. Further, from the array substrate 100 side,
An electrode transfer material for supplying a voltage to the 0-side counter electrode 204 is formed on the electrode transfer electrode around the seal member 106.

Subsequently, the array substrate 100 and the counter substrate 200 are arranged so that the alignment films 141 and 205 face each other, and the sealing material 106 is cured by heating, and the two substrates are bonded. At this time, a predetermined gap is formed between the array substrate 100 and the counter substrate 200 by a spacer (not shown).

Subsequently, the array substrate 10 is inserted through the liquid crystal injection port.
A liquid crystal composition 300 to which a chiral agent is added is injected between the liquid crystal composition 300 and the counter substrate 200, and the liquid crystal injection port is sealed with an ultraviolet curable resin. The injected liquid crystal composition 300 is
An alignment film 141 on the side of the array substrate 100;
A nematic liquid crystal layer having a twist angle of 90 degrees is formed by the alignment film 203 on the side.

The thickness of the liquid crystal layer depends on the reflection part PR of the pixel region P.
And the transmission part PT. In the reflection part PR, the thickness from the surface of the glass substrate 101 becomes larger than that of the transmission part PT, and the thickness of the liquid crystal layer in the reflection part PR is about 2.3 μm because the color filter CFR is formed on the bump 161. On the other hand, the thickness of the liquid crystal layer in the transmission part PT is about 5.1 μm.

For this reason, in the transmissive portion PT, the backlight light incident on the liquid crystal layer from the array substrate generates a phase difference of λ / 2 before transmitting to the counter substrate. In the reflection part PR, external light incident on the liquid crystal layer from the counter substrate side is λ in one way.
The reflected light generated by the reflection electrode 151R having a phase difference of / 4 reciprocates by λ / 2 before being emitted to the counter substrate side.
Is generated.

On the outer surface of the array substrate 100, a λ / 4 wavelength plate 181 and a polarizing plate 183 are laminated in this order.
In addition, a diffusion plate 207, λ /
The four-wavelength plate 209 and the polarizing plate 211 are stacked in this order.

The circularly polarized light generated by passing through the deflecting plate and passing through the phase difference plate turns ON the voltage to the liquid crystal layer 300.
By / OFF, the light is converted into circularly polarized light in the forward or reverse direction. Thereby, after passing through the phase difference plate again, the pass / non-pass of the polarizing plate is selected. By utilizing this, in a dark place, an image is displayed by selectively transmitting backlight light. In a bright place, an image is displayed by selectively reflecting external light.

As described above, the transflective liquid crystal display device includes the reflection portion PR and the transmission portion PT in one pixel region P. In a bright place, the reflection portion PR selectively reflects external light to form an image. Function as a reflective liquid crystal display device that displays
The transmissive portion PT functions as a transmissive liquid crystal display device that selectively transmits the backlight emitted from the backlight unit 30 and displays an image, thereby always driving the backlight unit as a transmissive liquid crystal display device. Power consumption can be greatly reduced as compared with the case where the power consumption is reduced.

In the above-described embodiment, the reflecting portion P
Adjustment of the spectral wavelength characteristic of the color filter CFR in R was performed by providing an opening penetrating to the reflective electrode 151R in the color filter CFR, but other methods may be used.

For example, as a first method, the adjustment of the spectral wavelength characteristic of the color filter CFR in the reflection section PR is performed as follows.
The adjustment may be performed by adjusting the amount of a coloring agent, for example, a dye contained in the color filter CF. That is, the color filter CFR in the reflection part PR is formed of a material having a smaller dye content than the color filter CFT in the transmission part PT. That is, the color filter CF
R has a spectral wavelength characteristic slightly lighter than the color filter CFT.

Thus, while the thickness of the color filter CF in the transmission part PT and the reflection part PR is the same, and the base material is the same, the optimum luminance is obtained by the backlight transmitted only once in the transmission part PT. Can be displayed, and at the reflecting portion PR, 2
It is possible to display an image with an optimum luminance by the external light that is transmitted twice.

Such a color filter CF is formed by, for example, an ink jet method. That is,
The formation of the color filter CF by the ink-jet method involves impregnating dyes corresponding to the respective colors by the ink-jet method in a color filter base material made of a transparent resin formed in advance. Therefore, at this time, by impregnating the color filter base material with the optimum amount of dye by the ink jet method, it is possible to realize a desired spectral wavelength characteristic.

As a second method, the adjustment of the spectral wavelength characteristic of the color filter CFR in the reflection section PR may be performed using a halftone mask as a mask used in a photolithography process for forming the color filter CF. . That is, the color filter CF is formed as follows.

First, a color filter material is formed on the entire surface of the substrate. Then, the formed color filter material is
Exposure is performed through a photomask having a shape corresponding to the pixel region. At this time, the photomask used is a halftone mask capable of adjusting the amount of transmitted light. This halftone mask does not completely block light but transmits only an arbitrary amount of light for each arbitrary region.

By performing exposure using such a mask, the film thickness of the color filter material can be made different between the transmission part PT and the reflection part PR. Thereby, for example, the film thickness of the color filter CFT in the transmission part PT is increased, and the film thickness of the color filter CFR in the reflection part PR is reduced, so that the color filter CFR has a slightly lighter spectral wavelength characteristic than the color filter CFT. It is possible to adjust as follows.

The influence on the cell gap can be avoided by knowing in advance the thickness of each color filter and adjusting the thickness of the bump disposed below the color filter CFR.

Thus, it is possible to form the color filters CFT and CFR having different film thicknesses in one photolithography process while forming the color filters CF in the transmission part PT and the reflection part PR using the same material. In the transmission part PT, it is possible to display an image of optimal luminance by the backlight light transmitted only once, and in the reflection part PR, to display an image of optimal luminance by external light transmitted twice. It is possible to do.

[0082]

As described above, according to the present invention, a high-quality image can be displayed regardless of the brightness under the use environment, even when the device functions as a reflection type or a transmission type. A liquid crystal display device and a method for manufacturing the liquid crystal display device can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of a liquid crystal display panel applied to a liquid crystal display device of the present invention.

FIG. 2 is a diagram schematically showing a configuration of a liquid crystal display device of the present invention.

FIG. 3 is a plan view schematically showing one pixel region of the liquid crystal display panel shown in FIG.

FIG. 4 is a cross-sectional view schematically showing a cross section when one pixel region shown in FIG. 3 is cut along line AB.

FIG. 5 is a diagram showing spectral wavelength characteristics of a color filter applied to the liquid crystal display device of the present invention.

FIG. 6 is a diagram illustrating a spectral wavelength transmittance of the color filter when the color filter having the spectral wavelength characteristic illustrated in FIG. 5 is used as a reflection type.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display panel 30 ... Backlight unit 100 ... Array substrate 121 ... Thin film transistor 151 ... Pixel electrode 151R ... Reflection electrode 151T ... Transmissive electrode 161 ... Bump 200 ... Counter substrate 300 ... Liquid crystal composition 400 ... Opening part P ... Pixel area PR ... Reflection part PT ... Transmission part CF (T, R) ... Color filter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/30 349 G09F 9/30 349B 349D (72) Inventor Keiji Tago 1-chome, Hara-cho, Fukaya-shi, Saitama No. 2 Inside the Toshiba Fukaya Plant (72) Inventor Yoshitaka Yamada 1-9-9 Hara-cho, Fukaya-shi, Saitama Prefecture No. 2 Inside the Toshiba Fukaya Plant (72) Inventor Tsuyoshi Takase, Hara-cho, Fukaya-shi, Saitama No. 9-2, Toshiba Fukaya Plant Co., Ltd. (72) Inventor Ryoichi Watanabe 1-9-2, Hara-cho, Fukaya-shi, Saitama F-Terminator, Toshiba Fukaya Plant Co., Ltd. 2H048 BA64 BB02 BB07 BB08 BB44 2H091 FA02Y FA08X FA08Z FA11X FA11Z FA14Z FA21Z FA23Z FA41Z GA13 LA16 2H092 GA40 JA24 NA01 PA08 PA12 PA13 5C094 AA51 BA03 BA43 CA19 CA24 EA04 EA06 EA07 EB02 ED03 ED11 GB10

Claims (9)

[Claims] 1. A liquid crystal display device comprising: a liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates; and a backlight unit for illuminating the liquid crystal display panel. A pixel region including a first color filter layer and a reflective electrode for reflecting external light, and a second color filter layer and a transmissive portion for transmitting backlight light from the backlight unit including a transmissive electrode; Wherein the first color filter layer and the second color filter layer are formed of the same material having the same thickness, and have different optical characteristics from each other. 2. The method according to claim 1, wherein the first color filter layer is disposed on the reflective electrode and has a spectral wavelength characteristic such that the first color filter layer is colored in a predetermined color by transmitting external light twice. The liquid crystal display device according to claim 1. 3. The device according to claim 1, wherein the first color filter layer is disposed on the reflection type electrode, and has a plurality of openings penetrating to the reflection type electrode in a plane thereof. Liquid crystal display. 4. The liquid crystal display device according to claim 1, wherein the first color filter layer and the second color filter layer have different coloring agent contents. 5. One of the substrates includes scanning lines arranged in a row direction on one main surface, signal lines arranged in a column direction orthogonal to the scanning lines, and the scanning lines and the signal lines. A switching element disposed at the intersection of the first and second pixel elements, and a pixel electrode composed of a reflective electrode and a transmissive electrode electrically connected to the switching element.
3. The liquid crystal display device according to 1. 6. The liquid crystal display device according to claim 1, wherein the reflection section includes a bump below the reflection type electrode. 7. A liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates, and a backlight unit for illuminating the liquid crystal display panel, wherein one pixel region formed on one of the substrates has A liquid crystal display comprising: a reflecting portion provided with one color filter layer and a reflective electrode for reflecting external light; and a transmitting portion provided with a second color filter layer and a transmissive electrode and transmitting the backlight from the backlight unit. In the method of manufacturing a device, the first color filter layer is formed on the reflective electrode by a photolithography process, and simultaneously, a plurality of openings penetrating to the reflective electrode are formed in the first color filter layer. A method for manufacturing a liquid crystal display device, comprising: 8. A liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates, and a backlight unit for illuminating the liquid crystal display panel, wherein one pixel region formed on one of the substrates has A liquid crystal display comprising: a reflecting portion provided with one color filter layer and a reflective electrode for reflecting external light; and a transmitting portion provided with a second color filter layer and a transmissive electrode and transmitting the backlight from the backlight unit. In the method for manufacturing a device, the first color filter layer and the second color filter layer are formed by an inkjet method, and the first color filter layer and the second color filter layer each include a colorant contained therein. A method for manufacturing a liquid crystal display device, wherein the amounts are different. 9. A liquid crystal display panel having a liquid crystal composition sandwiched between a pair of substrates, and a backlight unit for illuminating the liquid crystal display panel, wherein one pixel region formed on one of the substrates has a A liquid crystal display comprising: a reflecting portion provided with one color filter layer and a reflective electrode for reflecting external light; and a transmitting portion provided with a second color filter layer and a transmissive electrode and transmitting the backlight from the backlight unit. In the device manufacturing method, the first color filter layer and the second color filter layer are formed by a photolithography process, and the first color filter layer is exposed to light through a halftone mask to form the second color filter layer. A method for manufacturing a liquid crystal display device, wherein the film thickness is different from a color filter layer.