JP2006106088A - Method for manufacturing transflective display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a transflective display element with excellent visibility by reducing occurrence of air bubbles in sticking of a base layer. <P>SOLUTION: The method for manufacturing the transflective display element, having a transmissive region and a reflective region arranged inside a pixel, is provided with: a step to stick the light transmitting base layer with an uneven surface to a transparent substrate; a heating and pressurizing step to reduce the air bubbles occurring between the base layer and the substrate by heating and pressurizing the transparent substrate to which the base layer is stuck; and a film forming step to form a reflection diffusing film on a region of the uneven surface corresponding to the reflective region. In particular, the step to heat and pressurize the transparent substrate is conducted in surroundings of ≥50°C and ≤200°C, and ≥0.15 Pa and ≤0.5 Pa. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a transflective display element.

Conventionally, liquid crystal display elements have been used as display means for mobile phones and the like.
For example, a reflective liquid crystal display element performs display by reflecting light incident from the outside toward the front side of the liquid crystal display element. In a reflective liquid crystal display element, in order to obtain a bright display by efficiently using external light, a structure for emitting uniform light in a direction perpendicular to the display screen with respect to incident light from all angles is required.

  Conventionally, for example, the following manufacturing method of a reflective liquid crystal display element has been proposed. That is, after the base layer (thermosetting / photosensitive resin) is attached to the substrate, the thermosetting / photosensitive resin is photocured by exposing the thermosetting / photosensitive resin, and the inclination angle is less than a predetermined angle. A plurality of irregularities are formed. After the base layer is heated and reacted, a diffuse reflection film is formed on the uneven surface using a metal thin film made of aluminum or silver. In addition, since the metal thin film is formed on the uneven surface, the metal thin film has a diffusion function in addition to the reflection function (for example, Non-Patent Document 1).

  However, in recent years, in addition to the light reflection function of the reflective liquid crystal display element, a cellular phone or the like has a light transmission function for transmitting the light of the backlight arranged on the back side of the liquid crystal display element to the front side of the liquid crystal display element. There has been a demand for a transflective liquid crystal display element having the same. The transflective liquid crystal display element has, for example, a reflective film disposed for each pixel, a reflective region that reflects light input using the reflective film, and a transmission that transmits light input without a reflective film. In each pixel, a reflective area and a transmissive area are formed as continuous areas (for example, Patent Document 1).

Here, when the technique described in Non-Patent Document 1 is also applied to the technique described in Patent Document 1 (semi-transmissive liquid crystal display element), for example, the base layer described in Non-Patent Document 1 is light-transmitted. A method of additionally forming a transmissive region by removing a part of the diffuse reflection film (metal film) formed on the concavo-convex surface of the base layer surface for each pixel is considered.
Tsuruoka Yasuo, Shimazaki Toshikatsu, Yoshida Ken, “Reflective Base Film Material for Reflective Color LCD”, Hitachi Chemical Technical Report, Hitachi Chemical Co., Ltd., January 2002, No. 38, p. 15-18 JP 2001-281648 A (FIG. 1)

However, the inventor has discovered that when the base layer and the substrate are bonded together, air is trapped between the base layer and the substrate, resulting in bubbles.
In addition, when bubbles exist between the base layer and the substrate in the transmissive region, light passes through the base layer in the transmissive region, so that the bubbles appear, for example, as pinholes, which increases the visibility of the liquid crystal display element. It turns out that it will decrease.
The present invention has been made to solve such a problem, and reduces the bubbles generated when the base layer is pasted, so that a transflective liquid crystal display device with high visibility can be efficiently manufactured. An object is to provide a method for manufacturing a display element.

A method of manufacturing a transflective display device according to the present invention is a method of manufacturing a transflective display device in which a transmissive region and a reflective region are provided in a pixel, and a light-transmitting underlayer having an uneven surface is provided. An affixing step for affixing to a light-transmitting substrate; a heating and pressurizing step for reducing bubbles generated between the underlayer and the substrate by heating and pressurizing the substrate on which the underlayer is affixed; And a film forming step of forming a reflection diffusion film on the uneven surface and corresponding to the reflection area.
By such a method, bubbles generated when the base layer is attached can be reduced, and a transflective liquid crystal display element with good visibility can be efficiently manufactured.

  The heating and pressing step is preferably performed in an environment of 50 ° C. or more and 200 ° C. or less and 0.15 Pascal or more and 0.5 Pascal or less.

  Moreover, you may provide the baking process which heats the said base layer more than the temperature of the said heating-pressing process continuously after the said heating-pressing process.

  According to the present invention, it is possible to provide a method of manufacturing a transflective liquid crystal display element that can efficiently produce a transflective liquid crystal display element with good visibility by reducing bubbles generated when the base layer is attached.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of a transflective liquid crystal display element.
In FIG. 1, a transflective liquid crystal display element 10 is configured by sandwiching a liquid crystal 103 between two transparent substrates 101 and 102. The transparent substrates 101 and 102 are formed in a rectangular shape using, for example, light transmissive glass, polycarbonate, acrylic resin, or the like.
On the front surface of the transparent substrate 102 of the liquid crystal display element 10, a base layer 104, a reflection diffusion film 105, a color filter layer 106, a planarization film 106a, a transparent electrode 107, and an alignment film 108 are sequentially stacked.

The underlayer 104 is an underlayer for forming the reflective diffusion film 105, and is formed of a light transmissive thermosetting / photosensitive material. For example, an acrylic organic composition is used for the base layer 104. The ground layer 104 has a concavo-convex surface 104a formed with a plurality of concavo-convex surfaces on the front surface and a flat surface on the back surface.
The reflection diffusion film 105 is formed by depositing a metal having high reflectivity such as aluminum or silver on the surface of the base layer 104 by a metal sputtering method or a vacuum evaporation method. The reflective diffusion film 105 is removed at a portion corresponding to the transmissive region 150 so that the transmissive region 150 and the reflective region 160 are formed in the pixel.

  The transparent electrode 107 is formed of, for example, a transparent conductive thin film (ITO: Indium Tin Oxide) by photolithography. The alignment film 108 is formed of, for example, an organic thin film such as a polyimide thin film that is a polymer material, and plays a role of aligning the molecules of the liquid crystal 103 in a predetermined direction.

  A transparent electrode 109 and an alignment film 110 are laminated on the back surface of the transparent substrate 101 of the liquid crystal display element 10. The transparent electrode 109 is formed so as to be orthogonal to the transparent electrode 107. The polarizing plates 111 and 112 are optical members having a function of transmitting only a specific polarization component with respect to incident light. The polarizing plate 111 is attached to the front surface of the transparent substrate 101 via the optical compensation plate 115. The polarizing plate 112 is attached to the back surface of the transparent substrate 102 via an optical compensation plate 116. The spacers 113 are resin particles that control the height (cell gap) of the liquid crystal 103 between the transparent substrates 101 and 102 and are scattered throughout the entire range between the transparent substrates 101 and 102. The sealant 114 is an adhesive for bonding the rectangular transparent substrates 101 and 102 around.

  As shown in FIG. 1, in the transmissive region 150, light incident from the back side of the liquid crystal display element 10 (for example, backlight light) passes along the path indicated by the arrow M. Is transmitted to the front side of the screen. Further, in the reflection region 160, light (for example, natural light) incident from the front surface of the liquid crystal display element 10 is diffusely reflected by the diffuse reflection film 105 along the path indicated by the arrow N, and the front side of the liquid crystal display element 10. Is injected into.

Next, a method for manufacturing a transflective liquid crystal display element according to the present invention will be described with reference to the drawings.
FIG. 2 is a diagram showing a method for manufacturing a transflective liquid crystal display element according to the present invention.
In FIG. 2, the integrated base film 104b and base layer 104 are attached to the front surface of the cleaned transparent substrate 102 by thermocompression bonding while removing the protective sheet 104c (FIG. 2 (a)).
Specifically, with reference to FIG. 3, the pasting process of the base layer 104 corresponding to FIG.
FIG. 3 is a diagram for explaining a general pasting process of the underlayer.
In FIG. 3, an example in which the transparent substrate 102 is multi-faceted will be described. A plurality of transparent substrates 102 are arranged on the mother substrate (transparent substrate) 1000. The underlayer 104 is formed in a rectangular shape that is smaller than the outer shape of the mother substrate 1000. In addition, the base layer 104 is attached to the inner side of the outer periphery of the mother substrate 1000.

The base layer 104 is attached to the mother substrate 1000 by thermocompression using the roller 200 in an environment at a temperature of 100 ° C. to 140 ° C. At that time, the mother substrate 1000 is preheated to about 50 ° C.
As shown in FIG. 3A, the roller 200 is arranged in parallel with one side (for example, the side EF) of the rectangular mother substrate 1000. While moving the pressing area (the contact area between the roller 200 and the base film 104b) from the side EF toward the side GH (the B direction in FIG. 3A), the roller 200 moves through the base film 104b. The base layer 104 is pressed to attach the base layer 104 and the mother substrate 1000.
As shown in FIG. 3B, the protective film 104c is peeled off in accordance with the movement of the roller 200.

  In this case, after the protective film 104c is peeled off, when the base layer 104 is first pressed against the mother substrate 1000 by the roller 200 in the vicinity of the side EF, there is air between the mother substrate 1000 and the base layer 104 in the pressing region. The trapped air bubbles are generated between the mother substrate 1000 and the base layer 104. In FIG. 3A, when L1 = about 20 mm to about 30 mm, bubbles are generated in a region corresponding to the length of the side EF × L1 (the hatched portion in FIG. 3A). At this time, if the mother substrate 1000 is 480 mm × 360 mm, for example, and if the transparent substrate 102 can be multi-sided with 10 pieces (one row) × 10 pieces (one row), the display area is displayed on at least 10 transparent substrates 102. Bubbles will be generated in a part of. Most of the bubbles are removed in the heating and pressurizing step described later, and the bubbles can be reduced.

In FIG. 2, next, the base film 104b is photocured by irradiating the base film 104b with light with the base film 104b and the base layer 104 attached to the surface of the mother substrate 1000 (see FIG. 2). FIG. 2 (b)). At this time, the underlayer 104 is also cross-linked.
Next, the photocured base film 104b is peeled off to expose the uneven surface 104a formed on the surface of the base layer 104 (FIG. 3C).

Next, the mother substrate 1000 to which the base layer 104 is attached is left under high temperature and high pressure. Preferably, using an autoclave (not shown) that realizes a high-temperature and high-pressure environment in a sealed space, under an environment of 50 to 200 ° C. and 0.15 Pascal (Pa) or more and 0.5 Pascal (Pa) or less, The mother substrate 1000 with the base layer 104 attached is left to stand within 30 minutes ((d) in the figure).
If the underlayer 104 is, for example, an acrylic organic composition, the material itself is softened by being placed at a medium or high temperature of 50 ° C. or higher, and a high pressure is applied to the softened underlayer 104. Bubbles generated between the formation 104 and the mother substrate 1000 are pressed out. In addition, as will be described in a later-described baking step ((e) in the figure), the acrylic organic composition of the underlayer used in this embodiment is cured at a high temperature of 200 ° C. or higher.
In this way, bubbles generated when the base layer 104 is attached can be reduced.
In addition, it is more efficient and preferable to perform the below-mentioned baking process (the figure (e)) continuously after a heating-pressing process (the figure (d)).
FIG. 4 is a diagram showing a temperature-time relationship in the heating and pressing step and the baking step.
In FIG. 4, the heating and pressurizing step is performed using an autoclave (not shown) while increasing the temperature from 50 ° C. to 200 ° C. within about 30 minutes. The mother substrate 1000 is preheated to 50 ° C. in advance.

And the baking process of the base layer 104 is started from the time of exceeding 200 degreeC. Specifically, the base layer 104 is heated and baked at 200 ° C. to 250 ° C. for about 30 minutes or more ((e) in the figure). Note that the reason for baking is to increase the cross-linking density by curing the base layer 104.
As described above, the heating and pressurizing step (FIG. (D)) and the baking step (FIG. (E)) are continuously carried out by using an autoclave (not shown), so that the base layer is more efficiently obtained. Bubbles generated when 104 is attached can be reduced.
Next, a reflective diffusion film 105 such as a silver thin film or an aluminum thin film is formed on the surface of the concavo-convex surface 104a formed on the surface of the underlayer 104 by, for example, a metal sputtering method or a vacuum deposition method ((f) in the figure). .
Next, the portion corresponding to the transmission region 150 of the reflective diffusion film 105 is removed by etching ((g) in the figure).

Next, a color filter layer 106, a planarizing film 106a, a transparent electrode 107, and an alignment film 108 are provided on the front surface of the reflective diffusion film 105. A transparent electrode 109 and an alignment film 110 are provided on the back surface of the transparent substrate 101.
Next, the transparent substrate 101 and the transparent substrate 102 provided with the transparent electrodes 107 and 109, respectively, are bonded to each other with a sealant 114 after the spacer 113 is dispersed over the entire surface of the transparent substrate 101 or 102. Then, after the liquid crystal 103 is injected from the liquid crystal injection port (not shown), the liquid crystal injection port is sealed, and the optical compensators 115 and 116 and the polarizing plates 111 and 112 are attached to the transparent substrates 101 and 102. The display element 10 is completed.
By the manufacturing method as described above, bubbles generated when the base layer 104 is attached can be reduced, and a transflective liquid crystal display element with high visibility can be efficiently manufactured.
In the present embodiment, the temperature of the heating and pressurizing step has a profile that gradually increases as shown in FIG. 4, but it may be increased stepwise, or may be a constant temperature. You may make it hold | maintain.

It is a figure which shows the cross section of a transflective liquid crystal display element. It is a figure which shows the manufacturing method of the transflective liquid crystal display element which concerns on this invention. It is a figure explaining the general affixing process of a base layer. It is a figure which shows the temperature-time relationship of a heating-pressing process and a baking process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Liquid crystal display element, 101,102 Transparent substrate, 103 Liquid crystal, 104 Underlayer, 104a Irregular surface, 104b Base film, 104c Protective sheet, 105 Reflection diffusion film, 106 Color filter layer, 107, 109 Transparent electrode, 108, 110 Orientation Membrane, 111, 112 Polarizing plate, 200 roller, 1000 Mother substrate (transparent substrate).

Claims (3)

A method of manufacturing a transflective display element in which a transmissive region and a reflective region are provided in a pixel,
A pasting step of attaching a light-transmitting underlayer having an uneven surface to a light-transmitting substrate;
A heating and pressurizing step of heating and pressurizing the substrate to which the base layer is attached to reduce bubbles generated between the base layer and the substrate;
And a method of manufacturing a transflective display device, comprising a film forming step of forming a reflective diffusion film in a region corresponding to the reflective region on the uneven surface.   The method for producing a transflective display device according to claim 1, wherein the heating and pressing step is performed in an environment of 50 ° C to 200 ° C and 0.15 Pascals to 0.5 Pascals.   3. The method for manufacturing a transflective display device according to claim 1, further comprising a baking step in which the base layer is heated at a temperature equal to or higher than the temperature of the heating and pressing step after the heating and pressing step.

Images