JP2008111902A - Manufacturing method of display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a color filter substrate which is independent of formation area of a color filter. <P>SOLUTION: A manufacturing method of a display apparatus has a process, in which partition walls 74 partition between two or more subpixels 100 that constitutes pixels arranged in order on a substrate 72 and includes combination of different areas, droplets 134 of a liquid material consisting of a functional layer formation material and a solvent are dropped in the partitions 74 then the solvent is removed by drying to form the color filter 76. At least a first drop of the droplets 134 is dropped on the subpixel 100 with the largest area. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a display device.

In a display device using a white light source, such as a liquid crystal display device, when the white light is transmitted through a color filter substrate and converted into a single color light, the color display is performed by controlling the gradation (brightness) of the single color light. There are many. The color filter substrate is a colored material layer of each color of R (red), G (green), and B (blue) as a functional layer (hereinafter referred to as “color filter”) on a transparent substrate such as glass. .) Are arranged in a predetermined arrangement pattern such as a stripe arrangement. As a method for manufacturing a color filter having a large area at a low cost, a method of dropping a liquid material droplet having a coloring material as a solute into a partition surrounded by a partition wall (hereinafter referred to as “inkjet method”). Is known (Patent Document 1).
However, in recent years, a color filter substrate having a configuration in which M (magenta color), Y (yellow) C (cyan color), or the like is added in addition to the three primary colors to reproduce a color closer to natural light has been proposed (Patent Document). 2). Along with this, a method of providing a difference in the area of each color dot has also been proposed (Patent Document 3).

JP 2000-221319 A JP 2001-306003 A JP 2006-106659 A

  However, in the ink jet method, a liquid material composed of a solute of a coloring material and a solvent (hereinafter referred to as “liquid material”) is dropped, and then the solvent is dried and removed, so that color filters having different areas are formed. In some cases, the influence of the vaporized solvent may appear differently depending on the area. The present invention has been made in view of such a problem, and an object thereof is to provide a method for manufacturing a color filter substrate that does not depend on the formation area of the color filter.

  In order to solve the above-described problems, a method for manufacturing a display device according to the present invention includes a partition wall separating two or more sub-pixels including a combination of different areas constituting one pixel, and a functional layer forming material in the partition wall. And a step of forming a functional layer by drying and removing the solvent to form a functional layer, wherein the first droplet of the droplet has the largest area. It drops on the sub-pixel.

The solvent contained in the liquid material starts to evaporate immediately after being dropped, and changes the surrounding atmosphere. And the evaporation rate of the solvent contained in the liquid material dripped later is reduced, and the functional layer is formed in a stable state.
Moreover, the larger the area of the sub-pixel, the more the required amount of liquid material can be divided into more droplets and dropped. As the number of droplets dropped increases, the undulations that occur during the drying and removal of the solvent can be canceled out.
Therefore, with this manufacturing method, the uniformity of the functional layer thickness in the sub-pixel having the maximum area can be improved without degrading the uniformity of the functional layer thickness in the other sub-pixels. Uniformity can be improved. As a result, a display device with improved quality can be obtained.

  Further, in the method for manufacturing a display device according to the present invention, two or more subpixels including combinations with different areas are separated by a partition, and a liquid material droplet composed of a functional layer forming material and a solvent is placed in the partition. A method of manufacturing a display device including a step of forming a functional layer by dripping and removing the solvent by drying, wherein the dropping of the droplets is started in order from a sub-pixel having a larger area.

  According to such a manufacturing method, the effect of forming the functional layer in a stable state by changing the ambient atmosphere described above becomes more significant as the subpixel has a smaller area. Therefore, the uniformity of the functional layer thickness in the entire pixel can be further improved, and a display device with further improved quality can be obtained.

  In addition, in the method for manufacturing a display device according to the present invention, two or more subpixels including a combination with different areas constituting one pixel are divided by a partition wall, and a functional layer forming material is formed in the partition wall. A method of manufacturing a display device including a step of forming a functional layer by dropping a droplet of a liquid material composed of a solvent and drying and removing the solvent, wherein the area of the two or more subpixels is larger After the dropping of the droplet to the subpixel is finished, the dropping of the droplet to the smaller subpixel is started.

  According to such a manufacturing method, the next droplet can be dripped before the liquid material previously dripped becomes a functional layer in one partition wall, so that the above-described undulations cancel each other out. It can be demonstrated even more. Therefore, the uniformity of the functional layer thickness in the entire pixel can be further improved, and a display device with further improved quality can be obtained.

  Preferably, the functional layer forming material is a coloring material, and the functional layer is a color filter.

  Since the thickness uniformity of the color filter can be improved by such a manufacturing method, a display device with improved display performance can be obtained.

In this embodiment, a liquid crystal display device using a color filter as a functional layer will be described. The color filter is an element that changes white light (light including a wide range of wavelengths) into monochromatic light (light having a wavelength in a specific range) by transmitting light in a specific range of wavelengths. It is used for an apparatus that performs color display using a white light source. The liquid crystal display device enables color display based on the source of white light by changing the brightness of the transmitted light by controlling the gradation of the liquid crystal with a thin film transistor (hereinafter referred to as “TFT”).
(Liquid crystal display device)

  FIG. 1 is a schematic cross-sectional view showing an outline of a liquid crystal display device. The present liquid crystal display device includes a TFT substrate 10 in which TFTs 30 are arranged in a matrix, a color filter substrate 20 including a color filter and the like, and a seal material (not shown) that bonds both substrates with a predetermined gap therebetween. Liquid crystal 70 is sealed in a space surrounded by both substrates and the sealing material.

  The TFT substrate 10 is formed by arranging a large number of TFTs 30 in a matrix on a first substrate 22 made of a translucent material such as a quartz substrate with a base protective film 24 interposed therebetween. Each TFT 30 has a source region 32 and a drain region 34 into which impurities such as phosphorus and boron are introduced at both ends of a semiconductor layer such as polycrystalline silicon, and a channel region 36 is formed between both the regions. . Then, a gate insulating film 38 made of a silicon oxide film or the like is formed so as to cover the semiconductor layer, and a gate electrode 40 is formed on the channel region 36 through the gate insulating film 38 to constitute the TFT 30.

A first interlayer insulating film 42 made of a silicon oxide film or the like is formed on the TFT 30, and first contacts that penetrate the first interlayer insulating film 42 and reach the source region 32 and the drain region 34 of the semiconductor layer, respectively. A hole 52 and a second contact hole 54 are formed. A data line 56 made of a low resistance metal such as aluminum is connected to the source region 32 through the first contact hole 52, and a pixel made of a transparent conductive film such as indium tin oxide (hereinafter referred to as "ITO"). The electrode 60 is connected to the drain region 34 through the second contact hole 54. The TFT 30 is driven by an external circuit (not shown), and a voltage can be applied between the pixel electrode 60 to be connected and a common electrode described later. Then, by changing the alignment direction of the liquid crystal 70 between the two electrodes, it is possible to control the gradation of the amount of light transmitted from a white light source (not shown) disposed on the back side of the first substrate 22.
A second interlayer insulating film 44 and a protective film 46 are formed on the upper surfaces of the TFT 30 and the pixel electrode 60, and a first alignment film 48 made of polyimide or the like is formed over the entire surface of the TFT substrate 10.

The color filter substrate 20 includes a second substrate 72 made of a light-transmitting material similar to that of the TFT substrate 10, a partition wall 74 formed on the substrate, a color filter 76 formed in the partition wall, and the like. The partition walls 74 are formed in a lattice shape together with the black matrix 78 so as to surround a region facing the pixel electrode 60. A region surrounded by the partition wall 74 is the sub-pixel 100, which is red, green, blue (hereinafter, referred to as “R”, “G”, and “B”) and magenta, yellow, cyan (hereinafter, “M”, “Y”, respectively). The color filter of any one of the primary colors "" C ") is formed.
As described later, the area of the sub-pixel 100, that is, the area of the color filter 76 has two types, that is, a large area and a small area in the present embodiment. is there.

  In the present embodiment, the sub-pixel 100 is an element that modulates white light into monochromatic light whose brightness is controlled in gradation. As described above, the TFT 30 transmits white light emitted from the light source in multiple gradations. Therefore, a pixel composed of a plurality of subpixels 100 can emit light composed of arbitrary elements (lightness, saturation, hue), and a TFT display device in which a plurality of pixels are arranged in a matrix Any image can be formed.

The black matrix 78 is made of a light-shielding material such as metal, and suppresses light from the light source from leaking outside the region facing the pixel electrode. The partition wall 74 is made of an organic material such as acrylic resin or polyimide. As will be described later, the liquid material dropped when the color filter 76 is formed is prevented from moving to another region. A counter electrode 82 and a second alignment film 84 are formed on the color filter 76 and the black matrix 78 over the entire surface of the color filter substrate 20. The counter electrode 82 is formed of a transparent conductive material such as ITO similarly to the pixel electrode 60, and the second alignment film 84 is made of polyimide or the like.
(Color filter)

FIG. 2 is a perspective view showing the color filter 76 for one pixel formed on the second substrate. The black matrix is not shown. Six subpixels 100 are regularly arranged in a large and small size, surrounded by a partition wall 74, and a color filter 76 is formed in each partition, that is, the subpixel 100. The six subpixels 100 become one pixel and can emit arbitrary light. The code | symbol attached | subjected to each subpixel 100 shows the color of the color filter 76 formed with a coloring material.
Three colors R, G, and B having a large area are set as main elements for determining hue, and three colors M, Y, and C having a small area are set as auxiliary elements. Note that the area of the sub-pixel 100 is not limited to two stages, large and small, but can be further divided. For example, the auxiliary elements can be limited to one or two colors, and one or two of the main elements can have a larger area than the colors of the other main elements.

The thickness of the color filter 76 affects the brightness of monochromatic light obtained by transmitting white light, and is preferably as uniform as possible. However, as described above, when the color filter 76 is formed by the inkjet method, the above-described difference in the sub-pixel area can affect the uniformity. The manufacturing method of the color filter substrate 20 according to the present embodiment suppresses the influence, and forms the color filter 76 with improved film thickness uniformity on the pixel formed by combining the sub-pixels 100 having different areas. is there.
(Inkjet device)

  FIG. 3 shows a head of an ink jet apparatus used for manufacturing the color filter substrate 20. The ink jet apparatus used in the present embodiment has a head that can move relative to the color filter substrate 20, and droplets 134 can be dropped from a dropping portion provided on the head. FIG. 3A is a perspective view of the head 114, and FIG. 3B is a cross-sectional view of the dropping portion 127 of the head.

  As shown in FIGS. 3A and 3B, the head 114 has a plurality of nozzles 118 arranged at equal intervals. Specifically, the head 114 includes a diaphragm 126 and a nozzle plate 128 that defines the opening of the nozzle 118. A liquid pool 129 is located between the vibration plate 126 and the nozzle plate 128. The liquid pool 129 is always filled with a liquid material supplied from an external tank (not shown) through the supply hole 131. Has been.

  A plurality of partition walls 122 are positioned between the diaphragm 126 and the nozzle plate 128. A portion surrounded by the diaphragm 126, the nozzle plate 128, and the pair of partition walls 122 is the cavity 120. Since the cavities 120 are provided corresponding to the nozzles 118, the number of the cavities 120 and the number of the nozzles 118 are the same. The liquid material is supplied from the liquid pool 129 to the cavity 120 via the supply port 130 positioned between the pair of partition walls 122.

  On the diaphragm 126, the vibrators 124 are arranged corresponding to the cavities 120, respectively. Each of the vibrators 124 includes a piezoelectric element 124C and a pair of electrodes 124A and 124B sandwiching the piezoelectric element 124C. The control unit of the ink jet apparatus applies a driving voltage between the pair of electrodes 124A and 124B, whereby the droplet 134 is dropped from the corresponding nozzle 118.

A portion including one nozzle 118, a cavity 120 corresponding to the nozzle 118, and a vibrator 124 corresponding to the cavity 120 is a dropping unit 127. Therefore, one head 114 has the same number of dropping portions 127 as the number of nozzles 118.
As described above, the head 114 has a plurality of nozzles 118. That is, since the dripping part 127 is arrange | positioned at equal intervals, the several droplet 134 can be dripped simultaneously. However, since there is a limit to the miniaturization of the interval, when a plurality of droplets are dropped on a fine region as shown in FIG. 2, the head is moved at a pitch finer than the above interval and scanned multiple times (relative movement). )

  Further, the dropping unit 127 communicating with one liquid pool 129 drops a droplet 134 of the same liquid material (in this embodiment, a liquid material having a colored material of the same color as a solute). For the convenience of supplying the liquid material (due to the structure of the head), it is preferable that the dripping using one head 114 is up to three colors. Therefore, in order to form the color filter substrate 20 having pixels as shown in FIG. 2, the six colors are divided into two sets, and the droplets 134 are dropped a plurality of times for both combinations. In that case, the uniformity of the film thickness of the formed color filter 76 can be affected by the order of dropping.

  This embodiment improves the uniformity when the color filter substrate 20 having the sub-pixels 100 having four or more colors as described above and having a difference in area between the sub-pixels is formed by the ink jet method. Is.

  FIG. 4 is a diagram showing film thickness uniformity of the color filter when a droplet is dropped from a smaller pixel of subpixels having different areas as a comparative example. FIGS. 4A and 4A are top views of a total of six sub-pixels 100 constituting one pixel, and FIG. 4B is a cross-sectional view taken along the line AA ′. The sub-pixels of three colors R, G, and B are large-area sub-pixels, and the sub-pixels of a small area in which the three colors M, Y, and C are used supplementarily, and numbers from 1 to 5 in a circle Is the order of dropping droplets. The head 114 is scanned twice by the small area sub-pixels (100M, 100Y, 100C) and three times by the large area sub-pixels (100R, 100G, 100B), and the droplets 134 are dropped.

  Here, regarding the drying of the solvent, the solvent is completely removed by heating to form the color filter 76 before the counter electrode 82 is formed. However, the solvent evaporates even at room temperature. Therefore, the evaporation of the solvent (natural drying) starts immediately after the droplet 134 is dropped, and a considerable proportion is evaporated before the heating step. The evaporation changes the surrounding atmosphere in a direction to increase the partial pressure of the solvent. When the ambient temperature is constant, the solvent evaporation amount has a positive correlation with the area of the subpixel 100 where the droplet 134 is dropped, that is, the area of the color filter, and the existing amount of the droplet 134 within the area. , Has a negative correlation with the partial pressure.

  As shown in FIG. 4A, when the droplet 134 is first dropped on the small-area subpixel 100 and then dropped on the large-area subpixel 100, a solvent around the small-area subpixel 100 is placed on the periphery. The droplet 134 is dropped in a state where almost no atmosphere exists. As a result, the evaporation of the solvent proceeds rapidly and the effect extends to the (substantially) solidified shape. Specifically, as shown in FIG. 4B, the dropped center position becomes a raised mountain shape, and the film thickness uniformity of the color filter 76 in the partition 74 is deteriorated. Since the color filter 76 forms monochromatic light by absorbing light outside the predetermined wavelength region among the wavelengths included in the white light, the above phenomenon causes variations in the generated monochromatic light.

Since the scanning direction of the head 114 is constant, the same phenomenon occurs in the adjacent sub-pixel 100 having a small area. Therefore, streak-like unevenness may occur on the display surface of the display device as a whole. In the present invention, when the color filter 76 of a pixel in which sub-pixels 100 having different areas are combined is formed by an ink jet method, the film thickness uniformity of the color filter 76 is improved and the above-described stripe-like unevenness is suppressed. It is. Note that the large-area sub-pixel 100 is relatively less susceptible to the order of dropping. The reason will be described later.
(First embodiment)

  FIG. 5 shows a first embodiment of the present invention. FIG. 5A is a top view of a total of six sub-pixels 100 constituting one pixel, and FIG. 5B is a cross-sectional view taken along the line BB ′. The R, G, and B sub-pixels 100 are large-area sub-pixels 100, and the three-color M, Y, and C sub-pixels 100 are supplementarily used. The meanings of the numbers up to 5 are the same as in the comparative example described above.

  In the method of forming the color filter 76 of the present embodiment, first, a droplet 134 of a required amount of liquid material is dropped on the subpixel 100 having a large area, and then the droplet is dropped on the subpixel 100 having a small area. Is a feature. First, the head 114 scans the large-area subpixel 100 three times, and supplies a coloring material necessary for forming the color filter 76 on the large-area subpixel 100 (100R, 100G, 100B). Subsequently, the head 114 is continuously scanned twice over the small area sub-pixel 100, and a coloring material necessary for forming a color filter is supplied onto the small area sub-pixel 100 (100M, 100Y, 100C).

  Since droplets are dropped first on the large-area subpixel 100 and then dropped on the small-area subpixel 100, the droplets 134 dropped on the small-area subpixel 100 are previously dropped on the large-area subpixel 100. Natural drying starts in the atmosphere of the solvent generated from the droplets 134 dropped on the substrate. As a result, the evaporation of the solvent proceeds slowly and the effect extends to the (substantially) solidified shape. Specifically, as shown in FIG. 5B, as compared with the comparative example described above, the undulation in the sub-pixel 100 having a small area is suppressed, and the film thickness uniformity of the color filter 76 is improved.

  On the other hand, the undulations in the large-area subpixel 100 to which the droplets 134 are first dropped are not so different from those in the comparative example described above. The reason is that the area is affected. While the droplets 134 dropped on the large-area sub-pixel 100 are dried, there is not much atmosphere of the solvent previously evaporated. This is because the subpixel 100 dropped first has a small area, and thus the amount of solvent to be evaporated is small. However, if the area is large, the number of droplets dropped at a time increases, and the number of droplets to be dropped (the number of head scans) also increases. Therefore, the droplets 134 undulate each other until the solvent dries. The color filters 76 having a relatively flat surface are formed by canceling each other.

The undulation in the small area sub-pixel 100 is suppressed, and the undulation in the large area sub-pixel 100 does not change so much, so that the undulation of the color filter 76 is suppressed as a whole pixel, and the film thickness uniformity is improved. Therefore, the color filter substrate 20 having the color filters 76 of different areas can be obtained without causing quality defects such as stripes by the above manufacturing method.
(Second Embodiment)

FIG. 6 shows a second embodiment of the present invention. The R, G, and B sub-pixels 100 are large-area sub-pixels 100, and the three-color M, Y, and C sub-pixels 100 are supplementarily used. The meanings of the numbers up to 5 are the same as those in the first embodiment. A cross-sectional view is omitted.
In this embodiment, the droplets are dropped twice on the large-area sub-pixels 100R, G, and B, and then dropped twice on the small-area sub-pixels 100M, Y, and C to form the small-area sub-pixel 100. Supply the required amount of coloring material. Then, it is dropped once again on the large-area subpixels 100R, 100G, and 100B, and a required amount of coloring material is supplied to the large-area subpixels 100.

In the present embodiment, the droplet 134 is dropped on the large-area subpixel 100 before and after the droplet is dropped on the small-area subpixel 100. If all of the required amount of the large area sub-pixel 100 is dropped first, the liquid droplets drop to the small area sub-pixel 100 and the solvent evaporates. Since it evaporates, the surrounding atmosphere changes rapidly. However, as in the present embodiment, when the dropping on the large-area subpixel 100 is divided into two, the color filter 76 of the small-area subpixel 100 can be formed in a state where the surrounding atmosphere is kept relatively constant. As a result, it is possible to obtain the color filter substrate 20 in which the film thickness uniformity is further improved.
(Third embodiment)

  FIG. 7 shows a third embodiment of the present invention. In the pixel of the present embodiment, the sub-pixel 100 of a small area that is used as an auxiliary has two colors of M and C. The large-area subpixel 100 is the same as the first and second embodiments in that it has three colors of R, G, and B. The meanings of the numbers 1 to 5 in the circle are the same as those in the first and second embodiments.

As shown in the drawing, even when the number of colors forming the pixels is less than six, all types of liquid materials may not be dropped simultaneously due to the structure of the head 114. Also, as shown in the figure, the ratio of the areas of the large and small subpixels 100 may be relatively small. Even in such a case, the film thickness uniformity of the color filter substrate 20 can be improved by forming the color filter 76 first from the larger sub-pixel 100.
(Fourth embodiment)

FIG. 8 shows a fourth embodiment of the present invention. The meanings of the numbers 1 to 5 in the circle are also the same as those in the first to third embodiments. In the pixel of this embodiment, the sub-pixel 100 with a small area that is used as an auxiliary is only one color of M. The large-area sub-pixel 100 is the same as the first to third embodiments in that it has three colors of R, G, and B, but the sub-pixel 100R is slightly smaller than the other two colors. .
Thus, even when the area of the subpixel 100 is three or more, the color filter 76 is formed in the two types of subpixels 100R, G, and B having the larger area, and then the color filter is applied to the subpixel 100M having the smallest area. By forming 76, the solvent can be removed by drying in a stable atmosphere, and the film thickness uniformity of the color filter substrate 20 can be improved.

FIG. 2 is a schematic cross-sectional view illustrating an outline of a liquid crystal display device. The perspective view which shows the color filter as a functional layer for 1 pixel. The figure which shows the head of the inkjet apparatus used for manufacture of a color filter board | substrate. The figure which shows the film thickness uniformity of a color filter as a comparative example. The figure which shows the 1st Embodiment of this invention. The figure which shows the 2nd Embodiment of this invention. The figure which shows the 3rd Embodiment of this invention. The figure which shows the 4th Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... TFT substrate, 20 ... Color filter substrate, 22 ... First substrate, 24 ... Base protective film, 30 ... TFT, 32 ... Source region, 34 ... Drain region, 38 ... Gate insulating film, 40 ... Gate electrode, 42 ... first interlayer insulating film, 44 ... second interlayer insulating film, 46 ... protective film, 48 ... first alignment film, 52 ... first contact hole, 54 ... second contact hole, 56 ... data line , 60 ... Pixel electrode, 70 ... Liquid crystal, 72 ... Second substrate, 74 ... Partition, 76 ... Color filter as functional layer, 78 ... Black matrix, 82 ... Counter electrode, 84 ... Second alignment film, 100 ... Sub-pixel, 114 ... head, 118 ... nozzle, 120 ... cavity, 122 ... partition partition, 124 ... vibrator, 126 ... vibrating plate, 127 ... dropping portion, 128 ... nozzle plate, 129 ... puddle, 130 ... Feeding port, 131 ... feed hole, 134 ... droplets.

Claims (4)

A partition between two or more sub-pixels including a combination of different areas constituting one pixel is separated by a partition, and a droplet of a liquid material composed of a functional layer forming material and a solvent is dropped into the partition, A method of manufacturing a display device including a step of drying and forming a functional layer,
A method of manufacturing a display device, wherein the first droplet of the droplet is dropped on a sub-pixel having the largest area. Two or more sub-pixels including combinations with different areas are separated by a partition, a liquid material droplet composed of a functional layer forming material and a solvent is dropped into the partition, and the solvent is removed by drying to remove the functional layer. A manufacturing method of a display device including a step of forming,
A method for manufacturing a display device, characterized by starting the dropping of the droplets in order from a sub-pixel having a larger area. Two or more sub-pixels including a combination of different areas constituting one pixel are separated by a partition between the sub-pixels, and a liquid material droplet composed of a functional layer forming material and a solvent is dropped into the partition. , A method for producing a display device comprising a step of drying and removing the solvent to form a functional layer,
In the display device, after the dropping of the droplets to the sub-pixel having the larger area among the two or more sub-pixels is finished, the dropping of the droplet to the smaller sub-pixel is started. Production method.   The method for manufacturing a display device according to claim 1, wherein the functional layer forming material is a coloring material, and the functional layer is a color filter.

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