JP2004317611A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device of which the display characteristics are improved and the thickness is reduced by aligning a liquid crystal so as to form a retardation layer inside a cell without forming a new alignment layer and a method for forming the same. <P>SOLUTION: The alignment layer to align the liquid crystal is not separately formed but instead a color filter 21 or a protective film 22 composed of resin on the counter substrate side is effectively utilized. More specifically, by rubbing a surface of the color filter 21 or of the protective film 22, applying an ultraviolet curable liquid crystal thereto, aligning the liquid crystal in a specified direction via annealing treatment and curing the liquid crystal with an ultraviolet ray to form the retardation layer 25, and thus the retardation layer is fabricated inside the cell at a low cost. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to, for example, a reflection-type or transflective (combination-type) liquid crystal display device having both a reflection portion and a transmission portion, and a method of manufacturing the same.
[0002]
[Prior art]
Conventionally, as a display for a personal computer, a transmissive liquid crystal display that performs display using a backlight has been mainly used. In recent years, a display for a mobile electronic device such as a PDA (Personal Digital Assistant) or a mobile phone has been used. The demand for the device is rapidly increasing, and a reflection type liquid crystal display device capable of lowering power consumption as compared with a transmission type liquid crystal display device is receiving attention.
[0003]
The reflection type liquid crystal display device reflects the incident light from the outside with a reflection plate and performs display. Since a backlight is not required, the power consumption is reduced accordingly, and a transmission type liquid crystal display device is used. There is an advantage that the electronic device can be driven for a long time as compared with the case of performing the operation.
[0004]
In the reflection type, in order to obtain a sufficient contrast, display is performed by providing a film-like retardation plate between a substrate sandwiching a liquid crystal layer and a polarizing plate (for example, see FIGS. 1 to 4 of Patent Document 1). In principle, it is sufficient to have λ / 4, but since it has chromatic dispersion characteristics, in general, in order to eliminate it, it is combined with λ / 2 to form a two-layer structure and wide band.
[0005]
However, since this film-like retardation film is expensive and has a thickness of several tens of μm, this thickness also poses a problem in portable products that require a reduction in thickness.
[0006]
Therefore, studies have been made to adopt a liquid crystal polymer or the like as the retardation layer to create the inside of the cell (for example, see FIGS. 5 and 6 of Patent Document 1 and FIG. 1 of Patent Document 2). When a liquid crystal polymer is used as the retardation layer, the liquid crystal polymer needs to be oriented.
[0007]
[Patent Document 1]
Patent No. 3204260
[Patent Document 2]
JP 2001-222009 A
[0008]
[Problems to be solved by the invention]
However, there is a concern that adding a normal liquid crystal alignment film typified by polyimide inside the cell may lead to an increase in cost. Therefore, it is useful that the liquid crystal polymer can be oriented and used as the retardation layer without providing a new alignment film for providing the retardation layer inside the cell.
[0009]
The present invention has been made in view of the above circumstances, and an object of the present invention is to form a retardation layer by aligning liquid crystals inside a cell without providing a new alignment film, thereby improving display characteristics and improving the display characteristics. An object of the present invention is to provide a liquid crystal display device that can be made thinner.
Another object of the present invention is to provide a method for manufacturing a liquid crystal display device which can reduce costs by forming a retardation layer in which liquid crystals are aligned in a cell without providing a new alignment film. It is in.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a liquid crystal display device according to the present invention has a structure in which a reflective portion is formed on a part of one substrate sandwiching a liquid crystal layer, and a color filter and the color filter are provided on the liquid crystal layer side of the other substrate. A liquid crystal display device provided with a protective film for protecting the liquid crystal layer, a retardation layer made of a liquid crystal polymer is formed on the liquid crystal layer side of the other substrate, and the orientation of the retardation layer is the color filter or the color filter. It is regulated by a protective film.
[0011]
In the liquid crystal display device of the present invention described above, a retardation layer made of a liquid crystal polymer is formed on the liquid crystal layer side of the other substrate, and the orientation of the retardation layer is regulated by a color filter or a protective film. As described above, the liquid crystal polymer is usually aligned by using the color filter or the protective film made of resin, so that the separate and independent alignment film is omitted.
[0012]
In order to achieve the above object, in the method for manufacturing a liquid crystal display device according to the present invention, a reflective portion is formed on a part of one substrate sandwiching a liquid crystal layer, and a color filter and a color filter are provided on the liquid crystal layer side of the other substrate. A method of manufacturing a liquid crystal display device having a protective film that protects the color filter, wherein the step of forming the other substrate includes a step of rubbing the color filter or the protective film of the other substrate, Forming a retardation layer by applying a UV curable liquid crystal on the color filter or the protective film, orienting the liquid crystal in a predetermined direction, and then curing the liquid crystal.
[0013]
In the method of manufacturing a liquid crystal display device of the present invention, in the step of forming the other substrate, the color filter or the protective film of the other substrate is subjected to a rubbing treatment, and a UV curable liquid crystal is applied on the color filter or the protective film. After being oriented in a predetermined direction, it is cured to form a retardation layer. As described above, since a color filter or a protective film made of a resin is usually rubbed to function as an alignment film, a separate and independent alignment film is omitted.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a liquid crystal display device and a method of manufacturing the same according to the present invention will be described with reference to the drawings.
[0015]
First embodiment
FIG. 1 is a sectional view illustrating an example of the configuration of the liquid crystal display device according to the present embodiment.
The liquid crystal display device according to the present embodiment is a reflective liquid crystal display device. The liquid crystal display device is configured such that a liquid crystal layer 30 is sandwiched between a pair of first and second substrates 10 and 20 which are made of glass or the like and are arranged to face each other. A polarizing plate 31 is provided outside the second substrate 20.
[0016]
On the liquid crystal layer 30 side of the first substrate (TFT substrate) 10, a thin film transistor (TFT) described later is formed, and an interlayer insulating film 14 made of silicon oxide or the like is formed to cover the thin film transistor. A reflection electrode 16 made of silver or the like is formed on the film 14. An alignment film 18 made of polyimide or the like for controlling the alignment direction of the liquid crystal layer 30 is formed on the reflective electrode 16, and the surface of the alignment film 18 is rubbed.
[0017]
On the liquid crystal layer 30 side of the second substrate (counter substrate) 20, three color filters 21 of a red filter 21a, a green filter 21b, and a blue filter 21c are formed. The color filter 21 is a resin layer colored in each color by dyeing or pigment. On the liquid crystal layer 30 side of the normal color filter 21, a protective film (overcoat) 22 for protecting the color filter 21, a counter electrode 23 made of a transparent electrode such as ITO, and a polyimide or the like for regulating the alignment direction of the liquid crystal layer 30. In this embodiment, a retardation layer 25 made of a UV-curable liquid crystal polymer is provided between the color filter 21 and the protective film 22. The retardation layer 25 is adjusted to function as, for example, a λ / 2 plate.
[0018]
The liquid crystal layer 30 is filled with nematic liquid crystal, and is horizontally aligned by the alignment films 18 and 24. In the liquid crystal layer 30, the liquid crystal is horizontally aligned when no voltage is applied, and shifts vertically when a voltage is applied.
[0019]
FIG. 2 is a cross-sectional view illustrating an example of a detailed configuration of the first substrate in the case of a reflective liquid crystal display device.
As shown in FIG. 2, for example, a bottom gate thin film transistor Tr is formed on a substrate 10 made of glass or the like. That is, a gate insulating film 12 made of silicon oxide or the like is formed on the entire surface of the substrate 10 so as to cover the gate electrode 11. On the gate electrode 11, a semiconductor thin film 13 made of polysilicon or the like is formed via a gate insulating film 12.
[0020]
A first interlayer insulating film 14a made of silicon oxide or the like is formed so as to cover the thin film transistor Tr, and a source electrode (signal electrode) 15b and a drain electrode 15a embedded in the first interlayer insulating film 14a are formed by the thin film transistor Tr. Is electrically connected to The electrodes 15a and 15b are formed by patterning, for example, aluminum. A second interlayer insulating film 14b made of silicon oxide or the like is formed on the entire surface covering the electrodes 15a and 15b, and the reflective electrode 16a is connected to the drain electrode 15a via a contact hole formed in the second interlayer insulating film 14b. Is connected. Although not shown, the alignment film 18 shown in FIG. 1 is formed on the reflective electrode 16.
[0021]
In the above liquid crystal display device, the retardation layer 25 functions as a λ / 2 plate. In the off state, the liquid crystal molecules of the liquid crystal layer 30 are horizontally aligned, and the liquid crystal layer 30 functions as a λ / 4 plate. In the ON state, the liquid crystal molecules of the liquid crystal layer 30 shift to vertical alignment, and the function as a λ / 4 plate is lost.
[0022]
Assuming that the axis of the retardation layer 25 is 15 ° and the axis of the liquid crystal layer 30 is 75 ° with respect to the transmission axis of the polarizing plate 31, a wide band λ / 4 is obtained, and black display is performed when the voltage is OFF, that is, normally black. Mode.
When the voltage is ON, only the retardation layer 25 functioning as a λ / 2 plate remains, and the panel eventually functions as a one-wavelength plate. Accordingly, the transmittance is slightly reduced due to the influence of the angle with the polarizing plate, but a sufficient white display can be obtained.
[0023]
As described above, in the liquid crystal display device according to the present embodiment, the retardation layer 25 made of a UV-curable liquid crystal polymer is provided between the color filter 21 and the protective film 22 inside the liquid crystal panel. The liquid crystal display device is characterized in that the alignment of the liquid crystal constituting the retardation layer 25 is regulated by the color filter 21 without providing a separate and independent alignment film. That is, the color filter 21 has a function as an alignment film in addition to a function as a normal color filter.
[0024]
The method for manufacturing the liquid crystal display device according to the present embodiment will be described focusing on the point that a phase difference layer is formed by aligning liquid crystals using a color filter.
[0025]
After three color filters 21 are formed on a second substrate 20 made of glass or the like, the surface of the color filters 21 is directly rubbed, and then a UV curable liquid crystal monomer is spin-coated.
Subsequently, after annealing for aligning the UV curable liquid crystal, the liquid crystal is cured by UV light to form a retardation layer 25 made of a liquid crystal polymer. At this time, the thickness of the retardation layer 25 is adjusted so as to function as a λ / 2 plate. For example, it is about 2 μm.
[0026]
Next, the protective film 22 is formed by spin-coating, for example, an acrylic resin and polymerizing by an annealing process. The thickness of the protective film 22 is, for example, about 2 μm. Thereafter, the counter electrode 23 is formed by sputtering ITO, and the alignment film 24 made of polyimide or the like is formed, whereby the second substrate 20 as the counter substrate is manufactured.
[0027]
Lastly, after the first substrate (TFT substrate) 10 and the second substrate 20 which are separately manufactured are bonded to each other, the liquid crystal layer 30 is set to have a wavelength of λ / 4, and the liquid crystal is injected. A liquid crystal display device is manufactured by bonding the substrates 31 together.
[0028]
According to this embodiment, the color filter 21 made of resin on the counter substrate side is effectively used without separately providing an alignment film for aligning the UV-curable liquid crystal. That is, the surface of the color filter 21 is directly rubbed, a UV-curable liquid crystal is applied, and the liquid crystal is oriented in a predetermined direction by an annealing treatment, and then cured by UV light to form the retardation layer 25. A retardation layer can be formed inside the cell.
[0029]
Therefore, for example, when the display is performed in the normally black mode, a liquid crystal display device having a high contrast, good display characteristics, and a thin shape can be manufactured at low cost.
[0030]
Second embodiment
FIG. 3 is a cross-sectional view illustrating an example of the configuration of the liquid crystal display device according to the present embodiment. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0031]
On the liquid crystal layer 30 side of the second substrate (counter substrate) 20, a color filter 21, a protective film (overcoat) 22 for protecting the color filter 21, a counter electrode 23 made of a transparent electrode such as ITO, and a liquid crystal layer 30 are formed. An alignment film 24 made of polyimide or the like for controlling the alignment direction is formed. In the present embodiment, a retardation layer 25 made of a UV-curable liquid crystal polymer is provided between the protective film 22 and the counter electrode 23. The retardation layer 25 is adjusted to function as, for example, a λ / 2 plate.
[0032]
In the liquid crystal display device according to the present embodiment, a retardation layer 25 made of a UV-curable liquid crystal polymer is provided between the protective film 22 and the counter electrode 23 inside the liquid crystal panel. The liquid crystal display is characterized in that the alignment of the liquid crystal constituting the retardation layer 25 is regulated by the protective film 22 without providing a separate and independent alignment film. That is, the protective film 22 functions not only as a normal protective film but also as an alignment film.
[0033]
The method for manufacturing the liquid crystal display device according to the present embodiment will be described focusing on the point that the retardation layer is formed by aligning the UV curable liquid crystal using the protective film.
[0034]
After three color filters 21 are formed on the second substrate 20 made of glass or the like, an acrylic resin-based protective film 22 is formed on the color filters 21 and the surface of the protective film 22 is directly rubbed. The thickness of the protective film 22 is, for example, about 2 μm.
[0035]
Next, a UV curable liquid crystal monomer is spin-coated, annealed to align the UV curable liquid crystal, and then cured with UV light to form a retardation layer 25 made of a liquid crystal polymer. At this time, the thickness of the retardation layer 25 is adjusted so as to function as a λ / 2 plate. For example, it is about 2 μm. Thereafter, the counter electrode 23 is formed by sputtering ITO, and the alignment film 24 made of polyimide or the like is formed, whereby the second substrate 20 as the counter substrate is manufactured.
[0036]
Lastly, after the first substrate (TFT substrate) 10 and the second substrate 20 which are separately manufactured are bonded to each other, the liquid crystal layer 30 is set to have a wavelength of λ / 4, and the liquid crystal is injected. A liquid crystal display device is manufactured by bonding the substrates 31 together.
[0037]
According to the present embodiment, the protective film 22 made of acrylic resin on the counter substrate side is effectively used without separately providing an alignment film for aligning the UV curable liquid crystal. That is, the surface of the protective film 22 is directly rubbed, a UV-curable liquid crystal is applied, and is oriented in a predetermined direction by an annealing process, and then cured by UV light to form the retardation layer 25, so that the cost can be reduced. A retardation layer can be formed inside the cell.
[0038]
Therefore, for example, when the display is performed in the normally black mode, a liquid crystal display device having a high contrast, good display characteristics, and a thin shape can be manufactured at low cost.
[0039]
Third embodiment
FIG. 4 is a cross-sectional view illustrating an example of the configuration of the liquid crystal display device according to the present embodiment.
The liquid crystal display device according to the present embodiment is a transflective liquid crystal display device. The liquid crystal display device is configured such that a liquid crystal layer 30 is sandwiched between a pair of first and second substrates 10 and 20 which are made of glass or the like and are arranged to face each other. Polarizing plates 31 and 32 are provided outside the first substrate 10 and the second substrate 20.
[0040]
On the liquid crystal layer 30 side of the first substrate (TFT substrate) 10, a thin film transistor (TFT) described later is formed, and an interlayer insulating film 14 made of silicon oxide or the like is formed to cover the thin film transistor. A reflection electrode 16 made of silver or the like is formed on the film 14, and a reflection area is defined. A transparent electrode 17 of ITO or the like is formed in a region where the interlayer insulating film 14 has been removed, and a transmission region is defined. On the reflective electrode 16 and the transparent electrode 17, an alignment film 18 made of polyimide or the like for regulating the alignment direction of the liquid crystal layer 30 is formed, and the surface of the alignment film 18 is rubbed.
[0041]
On the liquid crystal layer 30 side of the second substrate (counter substrate) 20, a reflection red filter 21 a, a reflection green filter 21 b, and a reflection blue filter 21 c are formed in a portion facing the reflection electrode 16. A red filter for transmission 21d, a green filter for transmission 21e, and a blue filter for transmission 21f are formed in a portion facing the transparent electrode 17. That is, color filters 21 of a total of six colors are formed. The color filter 21 is a resin layer colored in each color by dyeing or pigment.
[0042]
On the liquid crystal layer 30 side of the color filter 21, a protective film 22, a counter electrode 23 made of a transparent electrode such as ITO, and an alignment film 24 are formed. In the present embodiment, the protective film 22, the counter electrode 23 Between them, a retardation layer 25 made of a UV-curable liquid crystal polymer is provided. The thickness of the retardation layer 25 is adjusted so as to function as a λ / 2 plate. For example, it is about 2 μm.
[0043]
The liquid crystal layer 30 is filled with nematic liquid crystal, and is horizontally aligned by the alignment films 18 and 24. In the liquid crystal layer 30, the liquid crystal is horizontally aligned when no voltage is applied, and shifts vertically when a voltage is applied. The liquid crystal layer 30 is adjusted to have λ / 4 in the reflection region and λ / 2 in the transmission region.
[0044]
FIG. 5 is a cross-sectional view illustrating an example of a detailed configuration of the first substrate in the case of a transflective (combination type) liquid crystal display device.
As shown in FIG. 5, a bottom-gate thin film transistor Tr is formed on a substrate 10 made of glass or the like, as in the first embodiment. In the present embodiment, a transparent electrode 17 made of ITO or the like connected to the drain electrode 15a is formed on the first interlayer insulating film 14a by patterning.
[0045]
A second interlayer insulating film 14b made of silicon oxide or the like is formed on the entire surface so as to cover the electrodes 15a, 15b, and 17, and is reflected to the drain electrode 15a via a contact hole formed in the second interlayer insulating film 14b. The electrode 16 is connected. In addition, the portion of the second interlayer insulating film 14b which will be a transmission region is removed, and the transparent electrode 17 is opened. Note that the alignment film 18 shown in FIG. 1 is formed on the reflective electrode 16 and the transparent electrode 17.
[0046]
The operation of the reflective display of the above-mentioned transflective liquid crystal display device is the same as that of the first embodiment, and therefore will be omitted, and the operation of the transmissive display will be described. In the off state, the liquid crystal molecules of the liquid crystal layer 30 are horizontally aligned, and the liquid crystal layer functions as a half-wave plate in the transmission region. In the ON state, the liquid crystal molecules of the liquid crystal layer 30 shift to the vertical alignment, and the function as a half-wave plate is lost.
[0047]
As the transmission configuration of normally black, the transmission axis of the retardation layer is 15 °, the axis of the liquid crystal layer 30 is 75 °, and the transmission axis of the rear polarizing plate 32 is 30 ° with respect to the transmission axis of the front polarizing plate 31. Then, black display is performed when the voltage is OFF.
When the voltage is ON, only a λ / 2 retardation plate is inserted between the polarizing plates 31 and 32 inclined by 30 °, so that a sufficient white display can be obtained.
[0048]
In the liquid crystal display device according to the present embodiment, in the transflective liquid crystal display device, the retardation layer 25 made of a liquid crystal polymer is provided inside the liquid crystal panel, and the orientation of the liquid crystal forming the retardation layer 25 is adjusted. It is characterized in that it is regulated by the protective film 22 without providing a separate and independent alignment film. That is, the protective film 22 functions not only as a normal protective film but also as an alignment film.
[0049]
The method for manufacturing the liquid crystal display device according to the present embodiment will be described focusing on the point that the retardation layer is formed by aligning the UV curable liquid crystal using the protective film.
[0050]
After a color filter 21 of six colors is formed on a second substrate 20 made of glass or the like, an acrylic resin-based protective film 22 is formed on the color filter 21, and the surface of the protective film 22 is directly rubbed. The thickness of the protective film 22 is, for example, about 2 μm.
[0051]
Next, a UV curable liquid crystal monomer is spin-coated, annealed to align the liquid crystal, and then cured with UV light to form a retardation layer 25 made of a liquid crystal polymer. At this time, the thickness of the retardation layer 25 is adjusted so as to function as a λ / 2 plate. For example, it is about 2 μm. Thereafter, the counter electrode 23 is formed by sputtering ITO, and the alignment film 24 made of polyimide or the like is formed, whereby the second substrate 20 as the counter substrate is manufactured.
[0052]
Finally, a first substrate (TFT substrate) 10 of a transflective type having a reflective portion and a transmissive portion in one pixel separately manufactured and a second substrate 20 are bonded to each other, and then liquid crystal is injected. By attaching the polarizing plates 31 and 32, a liquid crystal display device is manufactured.
[0053]
According to the present embodiment, the protective film 22 made of acrylic resin on the counter substrate side is effectively used without separately providing an alignment film for aligning the liquid crystal polymer. That is, the surface of the protective film 22 is directly rubbed, a UV-curable liquid crystal is applied, and is oriented in a predetermined direction by an annealing process, and then cured by UV light to form the retardation layer 25, so that the cost can be reduced. A retardation layer can be formed inside the cell.
[0054]
Therefore, for example, when a display is performed in a normally black mode, a thin transflective liquid crystal display device having high contrast, good display characteristics, and a thin shape can be manufactured at low cost.
[0055]
Fourth embodiment
In the present embodiment, a polyimide resin is used for the protective film 22 in the second and third embodiments. Other configurations are the same as those of the second and third embodiments.
[0056]
According to the present embodiment, a polyimide resin used as a normal liquid crystal alignment film is used as the protective film 22, the surface of the protective film 22 is directly rubbed, a UV-curable liquid crystal is applied, and annealing is performed. By aligning in a predetermined direction and then curing with UV light to form the retardation layer 25, the alignment regulating force of the liquid crystal constituting the retardation layer can be improved.
[0057]
Fifth embodiment
In the present embodiment, an epoxy resin is used for the protective film 22 in the second and third embodiments. Other configurations are the same as in the second embodiment.
[0058]
According to this embodiment, even when an epoxy resin is used as the protective film 22, the surface of the protective film 22 is directly rubbed, a UV curable liquid crystal is applied, and the surface is oriented in a predetermined direction by an annealing process. Thus, by setting the retardation layer 25 by curing with UV light, the alignment of the liquid crystal constituting the retardation layer can be regulated.
[0059]
Sixth embodiment
FIG. 6 is a cross-sectional view illustrating an example of the configuration of the liquid crystal display device according to the present embodiment.
The liquid crystal display device according to the present embodiment is a reflective liquid crystal display device. The same components as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.
[0060]
A color filter 21 of three colors is formed on the second substrate 20, a protective film 22 is formed thereon, and a phase difference layer 25 is formed on the protective film 22. The thickness of the retardation layer 25 is adjusted, for example, to function as a λ / 2 plate, and is, for example, about 2 μm.
[0061]
In the present embodiment, an alignment film 26, a retardation layer 27, and a protective film 28 are further formed between the retardation layer 25 and the counter electrode 23. The thickness of the retardation layer 27 is adjusted, for example, to function as a λ / 4 plate, and is, for example, about 1 μm. The alignment film 26 regulates the alignment of the liquid crystal that becomes the retardation layer 27.
[0062]
In the above liquid crystal display device, the retardation layer 25 functions as a λ / 2 plate, and the retardation layer 27 functions as a λ / 4 plate. In the off state, the liquid crystal molecules of the liquid crystal layer 30 are horizontally aligned, and the liquid crystal layer 30 functions as a λ / 4 plate. In the ON state, the liquid crystal molecules of the liquid crystal layer 30 shift to vertical alignment, and the function as a λ / 4 plate is lost.
[0063]
Assuming that the axis of the phase difference layer 25 is 15 °, the axis of the phase difference layer 27 is 75 °, and the axis of the liquid crystal layer 30 is 75 ° with respect to the transmission axis of the polarizing plate 31 when the voltage is OFF, Is displayed in white. Thus, by setting the axes of the retardation layers 25 and 27 to 60 °, λ / 4 of a wide band is obtained.
When the voltage is ON, only the broadband λ / 4 retardation plate composed of the retardation layers 25 and 27 is included, so that black display is performed.
[0064]
The method for manufacturing the liquid crystal display device according to the present embodiment will be described focusing on forming two retardation layers having a wide band of λ / 4.
[0065]
After three color filters 21 are formed on the second substrate 20 made of glass or the like, an acrylic resin-based protective film 22 is formed on the color filters 21 and the surface of the protective film 22 is directly rubbed. The thickness of the protective film 22 is, for example, about 2 μm.
[0066]
Next, a UV-curable liquid crystal is spin-coated, annealed to align the UV-curable liquid crystal, and then cured with UV light to form a retardation layer 25 made of a liquid crystal polymer. At this time, the thickness of the retardation layer 25 is adjusted so as to function as a λ / 2 plate. For example, it is about 2 μm.
[0067]
Next, an alignment film 26 made of polyimide or the like is printed on the retardation layer 25, rubbed, then spin-coated with a UV-curable liquid crystal, and annealed to align the UV-curable liquid crystal. To form a retardation layer 27 made of a liquid crystal polymer. At this time, the thickness of the retardation layer 27 is adjusted so as to function as a λ / 4 plate. For example, it is about 1 μm. Each of the retardation layers 25 and 27 is formed after rubbing at an angle of 60 ° so as to have a wide band of λ / 4.
Thereafter, an acrylic resin-based protective film 28 is formed, ITO is sputtered to form a counter electrode 23, and an alignment film 24 made of polyimide or the like is formed, whereby a second substrate 20 as a counter substrate is manufactured. You.
[0068]
Lastly, after the first substrate (TFT substrate) 10 and the second substrate 20 which are separately manufactured are bonded to each other, the liquid crystal layer 30 is set to have a wavelength of λ / 4, and the liquid crystal is injected. A liquid crystal display device is manufactured by bonding the substrates 31 together.
[0069]
According to the present embodiment, the number of alignment films for aligning the liquid crystal polymer is reduced by further forming the λ / 4 retardation layer 27 on the λ / 2 retardation layer 25 via the alignment film 26. A wide-band retardation layer is formed by using a two-layer structure while minimizing as much as possible. Therefore, for example, when the display is performed in the normally white mode, a thin liquid crystal display device having high contrast, good display characteristics, and a thin shape can be manufactured at low cost.
[0070]
The present invention is not limited to the above embodiments. The numerical values and the like described in the present embodiment are merely examples, and the present invention is not limited to these.
In addition, various changes can be made without departing from the spirit of the present invention.
[0071]
【The invention's effect】
According to the liquid crystal display device of the present invention, the display characteristics can be improved and the thickness can be reduced by forming the retardation layer by aligning the liquid crystal inside the cell without providing a new alignment film.
According to the method for manufacturing a liquid crystal display device of the present invention, the production cost can be reduced by forming a retardation layer in which liquid crystals are aligned inside the cell without providing a new alignment film.
[Brief description of the drawings]
FIG. 1 is a sectional view of a liquid crystal display device according to a first embodiment.
FIG. 2 is a cross-sectional view showing a detailed configuration of a first substrate shown in FIG.
FIG. 3 is a sectional view of a liquid crystal display device according to a second embodiment.
FIG. 4 is a sectional view of a liquid crystal display device according to a third embodiment.
FIG. 5 is a sectional view showing a detailed configuration of a first substrate shown in FIG. 4;
FIG. 6 is a sectional view of a liquid crystal display device according to a sixth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... board | substrate, 11 ... gate electrode, 12 ... gate insulating film, 13 ... semiconductor thin film, 14 ... interlayer insulating film, 15a ... drain electrode, 15b ... source electrode, 16 ... reflective electrode, 17 ... transparent electrode, 18 ... alignment film , 20... Second substrate, 21, 21 a, 21 b, 21 c, 21 d, 21 e, 21 f... Color filter, 22... Protective film, 23. Reference numeral 27: retardation layer 28: protective film 30: liquid crystal layer 31, 32: polarizing plate.

Claims (10)

A liquid crystal display device in which a reflection portion is formed on a part of one substrate that sandwiches a liquid crystal layer, and a color filter and a protective film that protects the color filter are formed on the liquid crystal layer side of the other substrate,
A liquid crystal display device, wherein a retardation layer made of a liquid crystal polymer is formed on the liquid crystal layer side of the other substrate, and the orientation of the retardation layer is regulated by the color filter or the protective film. The liquid crystal display device according to claim 1, wherein the protective film is formed of one of an acrylic resin, an epoxy resin, and a polyimide resin. The liquid crystal display device according to claim 1, wherein the retardation layer is a λ / 4 retardation layer. The liquid crystal display device according to claim 1, wherein the retardation layer is a λ / 2 retardation layer. The retardation layer is a λ / 2 retardation layer,
An alignment film formed on the liquid crystal layer side of the retardation layer,
2. The liquid crystal display device according to claim 1, further comprising a λ / 4 retardation layer made of a liquid crystal polymer formed on the alignment film. In a method for manufacturing a liquid crystal display device, a reflective portion is formed on a part of one substrate that sandwiches a liquid crystal layer, and a color filter and a protective film that protects the color filter are formed on the liquid crystal layer side of the other substrate. So,
In the step of forming the other substrate,
Rubbing the color filter or the protective film of the other substrate;
Applying a UV curable liquid crystal on the color filter or the protective film, orienting the liquid crystal in a predetermined direction, and then curing the liquid crystal to form a retardation layer. 7. The method for manufacturing a liquid crystal display device according to claim 6, wherein any one of an acrylic resin, an epoxy resin, and a polyimide resin is used as the protective film. 7. The method for manufacturing a liquid crystal display device according to claim 6, wherein in the step of forming the retardation layer, a λ / 4 retardation layer is formed. 7. The method for manufacturing a liquid crystal display device according to claim 6, wherein in the step of forming the retardation layer, a λ / 2 retardation layer is formed. Forming a retardation layer of λ / 2 in the step of forming the retardation layer;
After the step of forming the retardation layer,
Forming an alignment film on the liquid crystal layer side of the retardation layer,
Rubbing the alignment film;
7. The method for manufacturing a liquid crystal display device according to claim 6, further comprising a step of applying a UV curable liquid crystal on the alignment film, orienting the liquid crystal in a predetermined direction, and curing the liquid crystal to form a λ / 4 retardation layer. .

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