JP2018189771A - Display and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an anti-reflection function to a color filter of a display.SOLUTION: A display comprises: a plurality of drive pixel regions in which their reflective indices can be independently changed; and a color filter layer that has irregularities provided on the plurality of drive pixel regions. Preferably, the color filter layer is formed by an ink jet method; the ten-point average roughness of the irregularities is 0.6 μm or more and 2.2 μm or less; the average intervals between the convex parts of the irregularities along two directions in which the plurality of drive pixels are arranged are each 10 μm or more and 120 μm or less; the ratio of the area coverage of the color filter layer with respect to the drive pixel areas is 52% or more and 100% or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device and a manufacturing method thereof.

  With the spread of electronic information networks, for example, electronic publishing represented by electronic books has been performed. As a display device that displays electronic information of an electronic publication, for example, a self-luminous display device or a backlight display device is often used.

  However, the display screens of these display devices have higher luminance than that displayed on a print medium such as paper. For this reason, if the display screens of these display devices are continuously viewed over a long period of time, the user is likely to be fatigued. Furthermore, since these display devices consume a large amount of power, the display time is limited, for example, when battery-driven.

  On the other hand, for example, since a reflective display device represented by electronic paper displays electronic information by reflected light, the user can read the display of electronic information as if it were close to paper. For this reason, a user's fatigue is further reduced. Furthermore, since the reflective display device can exhibit display performance if it is exposed to sunlight or illumination light, for example, it is suitable for an outdoor signboard, for example. Since the reflective display device does not consume power other than rewriting screen information, it consumes less power and can be rewritten for a long time even when it is battery-powered. Reflective display devices are also actively used for applications such as electronic signboards and electronic price tags.

  In such a reflective display device, for example, monochrome display is sufficient if only text information is provided. However, in order to display electronic information in, for example, book illustrations, advertisements, signboards, displays that enhance the eye-catching effect, images, catalogs, shelf labels, price tags, instructions, etc., it is more preferable that color display is possible. With the colorization of display contents in these display applications, there is an increasing need for color display in a reflective display device.

  For example, the following reflective display devices have been proposed as reflective reflective devices that perform color display.

  In Patent Document 1, in a multicolor display panel in which a display body including particles that move or rotate by application of an electric field is disposed between a pair of substrates, at least one of which is transparent, on at least one transparent substrate of the pair of substrates. A multi-color display panel in which a color filter is formed has been proposed. Patent Document 1 describes a color filter in which three square color filters colored in three primary colors are arranged in a square lattice pattern.

  Patent Document 2 discloses a reflective display in which a plurality of color filters arranged in a predetermined pattern have a color filter in which a gap of 1 μm or more and 20 μm or less is provided without providing a black matrix between the color filters. A device has been proposed.

JP 2003-161964 A JP 2003-107234 A

  In a conventional reflective display device, a layer having an antireflection function such as an antiglare treatment has to be provided on the surface in order to prevent light such as sunlight from being reflected and making the display difficult to see.

  An object of this invention is to provide the antireflection function to color filters, such as electronic paper, so that it is not necessary to stick the member which has antireflection functions, such as an antireflection film.

  In order to solve the above problems, an aspect of the present invention includes a plurality of driving pixel regions whose reflectance can be changed independently, and a color filter layer having unevenness provided on the plurality of driving pixel regions, It is a display apparatus provided with.

  The ten-point average roughness of the unevenness of the color filter layer may be 0.6 μm or more and 2.2 μm or less.

  In the unevenness of the color filter layer, the average interval between the convex portions along the two directions in which a plurality of drive pixels are arranged is 10 μm or more and 120 μm or less, and the ratio of the coverage area of the color filter layer to the drive pixel region is It may be 52% or more and 100% or less.

  The color filter layer may include inorganic fine particles or organic fine particles of acrylic resin, styrene resin, or melamine resin in a weight ratio of 5% to 20%.

  Another aspect of the present invention is a method for manufacturing a display device, including a step of forming the color filter layer by an inkjet method.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of an interference fringe can be prevented, the color filter with an antireflection effect can be provided, and the reflection type display apparatus which does not need to provide an antireflection film separately can be provided.

Schematic longitudinal cross-sectional view which shows the structure of the principal part of the reflection type display apparatus which concerns on one Embodiment of this invention. Schematic plan view showing the arrangement of color filters according to a comparative example Schematic plan view showing the arrangement of color filters according to an embodiment of the present invention The top view of the pixel area concerning one embodiment of the present invention FIG. 3 is a plan view showing a printing position of a part of a color filter according to an embodiment of the present invention. FIG. 3 is a schematic plan view showing a part of a color filter according to an embodiment of the present invention. It is a figure which shows the film thickness and ten-point average roughness of the color filter which concerns on the Example of this invention.

  Hereinafter, a color filter and a reflective display device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view showing the configuration of the main part of the reflective display device according to this embodiment. Since FIG. 1 is a schematic diagram, the shape and dimensions are not necessarily the same as the actual ones (the same applies to other drawings).

  As shown in FIG. 1, the configuration of the main part includes a reflective display 1 (a reflective display device) including a base material 10, a first electrode layer 11, an adhesive layer 12, a reflective display layer 13, and a second electrode layer. 14, a light transmissive substrate 15 (substrate), and a color filter layer 17 are laminated in this order. An ink receiving layer 16 may be provided between the light transmissive substrate 15 (substrate) and the color filter layer 17.

  The reflective display 1 is driven on the basis of an image signal and a color filter layer 17 that limits incident light from the outside to three colors of a first color, a second color, and a third color, and the amount of reflected light of the three colors. A reflective display device that can display a color image. However, the color image by the reflective display 1 may be displayed in full color or may be multicolor display other than full color display. A location where no color filter is disposed may be provided to increase the brightness of the reflected light.

  The outer shape of the effective display screen of the reflective display 1 is not particularly limited. Here, the effective display screen means a screen capable of switching display. Below, as an example, it demonstrates as the outer shape of the effective display screen of the reflection type display 1 being a rectangle.

  The base material 10 is composed of a plate-like insulator. For example, a synthetic resin film, glass, or the like may be used as the material of the base material 10. A first electrode layer 11 is laminated on the surface of the substrate 10.

  The first electrode layer 11 applies to the reflective display layer 13 a driving voltage that changes the reflectance of the reflective display layer 13 described later. In the present embodiment, the first electrode layer 11 has a shape of a sub-pixel region so that a voltage can be independently applied to each sub-pixel region in the pixel region that is a display unit for color display of the reflective display 1. Corresponding to the arrangement, the plurality of subpixel electrodes are patterned.

  As will be described later, in the present embodiment, since the pixel region and the sub-pixel region are both rectangular in plan view, each sub-pixel electrode of the first electrode layer 11 is also rectangular. However, each sub-pixel electrode may have, for example, a pseudo-rectangular shape in which a concave portion or a convex portion is formed in a part of a rectangle depending on an arrangement position of a switching element to be described later.

  The subpixel electrodes in the first electrode layer 11 have the same configuration in that the reflectance of the reflective display layer 13 described later is changed between black and white. However, depending on the type of drive signal applied, the subpixel electrodes in each pixel region are classified into a first color subpixel electrode 11r, a second color subpixel electrode 11g, and a third color subpixel electrode 11b. The

  The first color sub-pixel electrode 11r, the second color sub-pixel electrode 11g, and the third color sub-pixel electrode 11b are gradations of the first color component, the second color component, and the third color component, respectively, in the pixel region. This is a drive electrode to which a drive voltage based on a drive signal for controlling is applied.

  Further, an achromatic region may be provided in the pixel region. In this case, an achromatic color sub-pixel electrode which is a drive electrode to which a drive voltage based on a drive signal for controlling the gray level of the achromatic color component is applied is provided. The first electrode layer 11 is formed of an appropriate metal material.

  A reflective display layer 13 is laminated on the first electrode layer 11 with an adhesive layer 12 interposed. The material of the adhesive layer 12 is not particularly limited as long as the first electrode layer 11 and the surface 13b of the reflective display layer 13 can be adhered to each other.

  The reflective display layer 13 has an appropriate layer structure that can switch and display at least white and black by applying an electric field in the layer thickness direction. In the present embodiment, the reflective display layer 13 has a configuration in which the reflectance gradually changes from the minimum value (black) to the maximum value (white) according to the magnitude of the electric field. Therefore, the reflective display layer 13 can express black and white gradation. The reflectance of the reflective display layer 13 may be changed on the surface 13a opposite to the surface 13b. For example, the reflective display layer 13 may use a configuration of a system selected from a reflective liquid crystal system, a cholesteric liquid crystal system, an electrophoresis system (microcapsule system, microcup system, etc.), an electrochromic system, and the like.

  The second electrode layer 14 is a transparent electrode laminated on the surface 13 a of the reflective display layer 13. In the present embodiment, the second electrode layer 14 is disposed in a range that covers the entire first electrode layer 11. Each drive electrode in the first electrode layer 11 and the second electrode layer 14 are connected to a drive power supply (not shown) via a switching element (not shown). For this reason, when the switching element is driven in accordance with the image signal, an electric field is generated between each drive electrode and the second electrode layer 14 by a drive voltage in accordance with the image signal. As a material of the second electrode layer 14, for example, a conductive transparent material such as indium tin oxide (ITO) may be used.

  The light-transmitting substrate 15 is a layered portion that has a light-transmitting property of visible light laminated on the second electrode layer 14. As a material of the light transmissive substrate 15, for example, a glass substrate may be used. As a material of the light transmissive substrate 15, for example, a film substrate such as a PET (polyethylene terephthalate) film or a PEN (polyethylene naphthalate) film may be used. An ink receiving layer 16 that holds ink for forming a color filter layer 17 to be described later may be formed on the surface 15 a of the light transmissive substrate 15. When the color filter layer 17 is formed by printing such as an inkjet method, it is preferable to provide the ink receiving layer 16. In the present embodiment, an example in which the reflective display 1 includes an ink receiving layer 16 will be described.

  The ink receiving layer 16 is a light-transmitting layered portion formed to hold a color filter layer 17 described later on the light-transmitting substrate 15. The thickness of the ink receiving layer 16 may be 4 μm or more and 10 μm or less. When the thickness of the ink receiving layer 16 is less than 4 μm, the solvent in the ink cannot be absorbed and there is a possibility that the ink spreads too much. Further, if the thickness of the ink receiving layer 16 is attempted to be less than 4 μm in manufacturing, there may be a portion where the ink receiving layer 16 is not formed due to manufacturing variations. When the ink receiving layer 16 exceeds 10 μm, the distance between the reflective display layer 13 and a color filter layer 17 described later becomes too large. For this reason, when the light reflected by the reflective display layer 13 diffuses and the amount of light transmitted through the color filter layer 17 described later decreases, the color reproducibility may decrease. The ink receiving layer 16 is laminated on the surface 15 a opposite to the surface in contact with the second electrode layer 14 in the light transmissive substrate 15.

  As the material of the ink receiving layer 16, an appropriate material capable of holding ink for forming the color filter layer 17 described later is used. As the ink receiving layer 16, for example, urethane resin, polyester resin, acrylic resin, vinyl alcohol resin, or the like may be used. In order to improve the surface blocking (sticking) prevention performance at the time of lamination, it is more preferable that the material of the ink receiving layer 16 includes a silicone resin. It is more preferable that the ink receiving layer 16 is made of a material having a high visible light transmittance and a property that hardly causes discoloration or discoloration of ink received in a use environment. The ink receiving layer 16 is more preferably formed of a film-holding material so that the uniformity of ink wetting and spreading is not impaired when the color filter layer 17 described later is formed. Examples of the material of the ink receiving layer 16 include, for example, an inkjet recording medium described in JP 2000-43305 A and an inkjet printer recording medium described in JP 2008-272972 A.

  The method for forming the ink receiving layer 16 is not particularly limited. For example, the ink receiving layer 16 may be formed by coating an ink receiving layer forming coating liquid for forming the ink receiving layer 16 on the light-transmitting substrate 15 and then drying or solidifying it. Good. Examples of the solvent for forming the ink receiving layer forming coating liquid include water, an aqueous solvent such as IPA (isopropyl alcohol) or an alcohol solvent, and an organic solvent. For example, when the ink receiving layer 16 is mainly composed of a urethane resin, an organic solvent such as toluene or ethyl acetate that is highly soluble in the urethane resin may be used in the ink receiving layer forming coating solution. . The coating device for the ink receiving layer forming coating liquid is not particularly limited. For example, examples of the coating apparatus include a die coater, a spin coater, and a bar coater. As a method for drying the ink receiving layer forming coating liquid, for example, heating, vacuum decompression, or the like may be used. As a method for solidifying the ink receiving layer forming coating liquid, for example, when the coating liquid is a UV curable resin, UV light irradiation may be used.

The color filter layer 17 is laminated on the surface 16 a of the ink receiving layer 16 in the light transmissive substrate 15. The color filter layer 17 includes a plurality of first color filters 17r (color filters), second color filters 17g (color filters), and third color filters 17b (color filters).
The first color filter 17r has a transmission wavelength band that transmits only the wavelength component of the first color.
The second color filter 17g has a transmission wavelength band that transmits only the wavelength component of the second color.
The third color filter 17b has a transmission wavelength band that transmits only the wavelength component of the third color.
The first color, the second color, and the third color are not particularly limited as long as they are non-white, have different wavelength bands, and a combination of these allows full color display or multicolor display. The combination of the first color, the second color, and the third color is preferably selected so as to become white light when the transmitted light of each color is mixed in order to perform full color display. For example, the first color, the second color, and the third color may be red, green, and blue.

  Moreover, you may provide the transparent resin film layer 17w mentioned later in a color filter layer.

  Hereinafter, for simplicity, the first color filter 17r, the second color filter 17g, and the third color filter 17b may be collectively referred to as each color filter.

  The first color filter 17r, the second color filter 17g, and the third color filter 17b have a first color subpixel electrode 11r and a second color subpixel electrode 11g with the reflective display layer 13 interposed therebetween. , And the third color sub-pixel electrode 11b. In the present embodiment, a light-transmitting layered portion in which the second electrode layer 14, the light-transmitting base material 15, and the ink receiving layer 16 are laminated is provided between each color filter and the surface 13 a of the reflective display layer 13. Separated by.

  Next, the configuration of the pixel region and the arrangement pattern of the color filter layer 17 in plan view will be described. For comparison with the present embodiment, FIG. 2 shows a schematic plan view showing a partial shape of a general color filter. Each area surrounded by a dotted line in FIG. 2 indicates a sub-pixel area.

  FIG. 3 is a schematic plan view showing the shape of a part of the color filter of the present embodiment. In FIG. 3, the X direction is a direction from the left side to the right side in the figure, and the Y direction is a direction from the upper side to the lower side in the figure. The arrangement pattern of each color filter as shown in the color filter layer 17 is repeated in the X direction (first direction) and the Y direction (second direction) over the entire effective display screen (not shown).

A plan view of the pixel region P is shown in FIG. Each pixel region P is formed by adjoining a total of four regions, that is, a rectangular sub-pixel region which is a unit for changing the reflectance in the reflective display layer 13, two regions in the X direction and two regions in the Y direction. Each sub-pixel region in each pixel region P includes three sub-pixel regions, a first sub-pixel region 13R, a second sub-pixel region 13G, and a third sub-pixel region 13B, and a fourth sub-pixel region 13W. Divided into four sub-pixel regions.
The first sub-pixel region 13R is a sub-pixel region whose reflectance is changed by the first-color sub-pixel electrode 11r, and is a rectangular region that covers the first-color sub-pixel electrode 11r.
The second sub-pixel region 13G is a sub-pixel region whose reflectance is changed by the second-color sub-pixel electrode 11g, and is a rectangular region that covers the second-color sub-pixel electrode 11g.
The third sub-pixel region 13B is a sub-pixel region whose reflectance is changed by the third-color sub-pixel electrode 11b, and is a rectangular region that covers the third-color sub-pixel electrode 11b.
The fourth sub-pixel region 13W is a sub-pixel region whose reflectance is changed by the achromatic color sub-pixel electrode, and is a rectangular region that covers the third-color sub-pixel electrode 11w.

  The width in the X direction of each pixel region P is WX, and the width in the Y direction is WY. For this reason, the arrangement pitch of each pixel region P in the X direction and the Y direction is also WX and WY, respectively. The width in the X direction of each sub-pixel region is wX (= WX / 2), and the width in the Y direction is wY (= WY / 2). For example, wX and wY may be 80 μm or more and 300 μm or less. In the following description, when dimensional examples of each part are described using specific numerical examples, as an example, it may be described that wX = 170 (μm) and wY = 170 (μm).

  Each pixel region P is adjacent to each other in the X direction and the Y direction, and is repeatedly arranged.

  Next, the arrangement of the color filters of the color filter layer 17 will be described. In this embodiment, the external shape of each color filter in plan view is a substantially rectangular shape including a square (including a rectangular shape). Here, the “substantially rectangular shape” is because, for example, a shape in which minute unevenness is generated on each side or each corner is rounded may be included. When measuring various gap sizes to be described later, the measurement is performed from the longest linear portion (hereinafter referred to as a side) in the outline of each color filter in plan view. For example, when the outer corner is rounded, the gap size from the rounded portion is ignored. When minute unevenness is formed on each side of the color filter as shown in FIG. 3, a straight line obtained by averaging the unevenness is regarded as the side.

  The first color filter 17r, the second color filter 17g, and the third color filter 17b are respectively centered in the X and Y directions on the first subpixel region 13R, the second subpixel region 13G, and the third subpixel region 13B. Be placed.

  When the transparent resin film layer 17w is provided, the transparent resin film layer 17w is disposed at the center in the X and Y directions on the fourth sub-pixel region 13W.

  Note that each unit rectangular region (each pixel region P) of the comparative example is arranged in the same manner as the pixel region P in the present embodiment. For this reason, the arrangement patterns of the first color filter 17r, the second color filter 17g, and the third color filter 17b arranged in each unit rectangular area P are the same. In the plan view shape of the color filter, the width Lx in the X direction is 5 to 20 μm thinner than wX. The width Ly in the Y direction is wY. For example, wX = 170 (μm) wY = 170 (μm), and the width Lx of each color filter is 150 μm and Ly is 170 μm.

  Each such color filter is formed by applying ink of the color of each color filter on the ink receiving layer 16 by printing and solidifying. In this case, the color filter is formed without forming a black matrix by separately applying the ink to the formation regions of the first color filter 17r, the second color filter 17g, and the third color filter 17b. Layer 17 is formed. Since the color filter layer 17 loses light amount loss due to the black matrix, the transmitted light amount of the color filter layer 17 is further improved as compared with the case of having the black matrix.

  When the color filter layer and the transparent resin film layer 17 are formed by ink application, an appropriate ink application method capable of separately applying ink is used as the ink application method. Examples of ink application methods suitable for forming the color filter layer and the transparent resin film layer 17 include a screen printing method, an offset printing method, and an ink jet printing method. In particular, the inkjet printing method is more preferable in that the alignment of the arrangement position of the color filter layer 17 with respect to the first electrode layer 11 is easy and the productivity is increased.

  The area of the colored portion of the color filter is preferably 52% or more and 100% or less with respect to the pixel region P. If the area of the color filter is smaller than that, the saturation of the displayable color will be low and light. Moreover, there is a drawback that the antireflection effect is also lowered. If it is 52% or more, the saturation is high and the antireflection effect is sufficiently exhibited. The area of the color filter is preferably as large as possible. However, when different colors are adjacent to each other in the sub-pixel, if the distance is too close, the saturation decreases due to light color mixing or ink color mixing.

  The color filter layer and the transparent resin film layer 17 form gentle peaks and valleys (unevenness) and are adjusted by the ink discharge amount from the inkjet ink so that the ten-point average roughness is 0.6 μm or more and 2.2 μm or less. By forming it, an antireflection effect is suitably obtained. The ten-point average roughness is measured by measuring the color filter with a film thickness meter, for example, with a width of 150 μm, and the average value of the absolute values P1 to P5 of the highest peak from the highest peak to the fifth peak from the center line and five from the lowest valley bottom. It is obtained as the sum of the absolute values of the absolute values of the elevations V1 to V5 at the bottom of the valley. When the average roughness is smaller than 0.6 μm, the difference between the peaks and valleys becomes slight and the antireflection effect is lowered. When it exceeds 2.2 μm, the mountain portion is easily scraped by an external force, and surface scratches are likely to occur. The center line is the average value of all measurement points measured in the width direction.

  It is preferable to adjust the print data so that the average interval between the peaks in the X direction and the Y direction is 10 μm or more and 120 μm or less. When it becomes 10 μm or less, rainbow-colored interference fringes begin to appear. When it exceeds 120 μm, the antireflection effect is lowered. Preferably, the ratio of the average valley height to the average peak height is in the range of 25% to 70%. The smaller the amount of ink discharged from the inkjet ink, the easier it is to adjust, and the amount of liquid per droplet is preferably 4 pl to 32 pl. When the ink jet method is used in this way, the formation of the valleys and valleys having the above-described preferable characteristics can be easily performed.

  Examples of the method of solidifying the ink after being applied on the ink receiving layer 16 include a method of drying by heating, air blowing, reduced pressure, or the like. For example, when the ink is an energy ray curable ink such as a UV ink, a method of irradiating energy rays such as UV light or an electron beam can be used. Two or more combinations of these solidification methods may be used. In particular, when UV ink is used, the color filter layer 17 and the transparent resin film layer 17 are formed even if the UV ink is directly applied to the surface of the light-transmitting substrate 15 without providing the ink receiving layer 16. Is possible.

  Next, the ink when the color filter layer 17 is formed by the ink jet printing method will be described. The material of the ink forming each color filter (hereinafter simply referred to as ink) may include a colorant, a binder resin, a dispersant, and a solvent. The ink material forming the transparent resin film layer 17w may contain a binder resin, a dispersant, and a solvent. As the colorant contained in the ink, all pigments can be used regardless of organic pigments, inorganic pigments, dyes and the like. As the colorant, organic pigments are more preferable, and those having excellent light resistance are more preferable.

  Specific examples of the pigment used as the colorant include C.I. I. Pigment Red 9, 19, 38, 43, 97, 122, 123, 144, 149, 166, 168, 177, 179, 180, 192, 215, 216, 208, 216, 217, 220, 223, 224, 226, 227, 228, 240, 254, C.I. I. Pigment Blue 15, 15: 3, 15: 6, 16, 22, 29, 60, 64, Pigment Green 7, 36, 58, C.I. I. Pigment Red 20, 24, 86, 81, 83, 93, 108, 109, 110, 117, 125, 137, 138, 139, 147, 148, 153, 154, 166, 168, 185, C.I. I. Pigment Orange 36, C.I. I. Pigment Violet 23, C.I. I. Pigment Yellow 150 and the like. Furthermore, in order to obtain a required hue, a colorant in which two or more kinds of pigments selected from an appropriate colorant group including these colorants are mixed may be used.

  Examples of the binder resin used for the ink material include casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin, and polyolefin resin. These are appropriately selected in relation to the pigment used as the colorant. For example, when heat resistance or light resistance is required, a melamine resin, an acrylic resin, an epoxy resin, or the like may be used as the binder resin used for the ink material. As the binder resin, one kind of resin may be used alone, or two or more kinds may be mixed and used.

  The dispersant used for the ink material is used to improve the dispersion of the colorant in the binder resin described above. Examples of the dispersant include nonionic surfactants and ionic surfactants. Examples of nonionic surfactants include polyoxyethylene alkyl ethers. Examples of the ionic surfactant include, for example, sodium alkylbenzenesulfonate, poly fatty acid salt, fatty acid salt alkyl phosphate, tetraalkylammonium salt, and other organic pigment derivatives and polyesters. One type of dispersant contained in the ink may be used alone, or two or more types may be used in combination.

  In order to further enhance the antireflection effect, for example, inorganic fine particles such as silica having a color filter weight ratio of 5% or more and 20% or less, organic fine particles of acrylic resin, styrene resin, or melamine resin may be included. It is more preferable to use a resin with high transparency. Magnesium fluoride or silicon dioxide particles having a particle diameter of 0.01 μm to 1.0 μm may be contained.

  As characteristics of the solvent used in the ink, it is more preferable that the surface tension is 35 mN / m or less and the boiling point is 130 ° C. or higher in consideration of suitability in ink jet printing. If the surface tension exceeds 35 mN / m in the solvent, the stability of the dot shape during ejection in ink jet printing may be impaired. If the solvent has a boiling point of less than 130 ° C., it tends to dry in the vicinity of the ink jet nozzle, so that defects such as nozzle clogging may easily occur. The viscosity of the solvent is more preferably 5 cps or more and 20 cps or less.

  Examples of the type of solvent used for the ink material include carbitols. Specific examples of the carbitols include carbitol solvents such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether, or their cellosolves and acetate compounds of carbitols. Other examples of the type of solvent used for the ink material include gamma butyrolactone, diethylene glycol monoethyl ether acetate, butyl diglycol acetate, and the like. The above-mentioned solvent may be used by mixing two or more kinds of solvents as necessary.

  Next, an ink jet apparatus used for the ink jet printing method for forming the color filter layer 17 will be described. As an ink jet device, there are a piezo method and a thermal method depending on the ink discharge method, and it is more preferable to use a piezo ink jet device. The ink jet apparatus includes a mounting table, an ink jet head, and a relative movement mechanism that relatively moves the mounting table and the ink jet head in at least two axial directions parallel to the mounting surface. On the mounting surface of the mounting table, a laminated body including the light transmissive substrate 15 on which the ink receiving layer 16 is formed can be mounted. In this laminated body, at least a part of the second electrode layer 14, the reflective display layer 13, and the first electrode layer 11 may be laminated, or these may not be laminated.

  When ink is applied to all color filter formation regions to form an ink layer, the ink layer is solidified by a solidification method corresponding to the type of ink. The ink layer is dried by, for example, heating, blowing, or decompressing. For example, when UV ink is used as the ink, the ink layer is solidified by irradiation with UV light.

  Next, the operation of the reflective display 1 of the present embodiment will be described focusing on the operation of the color filter layer 17.

  In the reflective display 1, when a voltage corresponding to an image signal is applied between the first electrode layer 11 and the second electrode layer 14 in each pixel region P, the reflective display layer 13 is driven. . That is, according to the voltages applied to the first color sub-pixel electrode 11r, the second color sub-pixel electrode 11g, and the third color sub-pixel electrode 11b, the reflection of the reflective display layer 13 at a portion facing them. The rate is switched. Thereby, the display state of the reflective display layer 13 is switched to white, gray, black, or the like in each sub-pixel region.

  The light incident on the reflective display 1 from the color filter side is transmitted through the color filter in the colored portion region, reflected by the reflective display layer 13 in the sub-pixel region corresponding to the color filter, and then incident on the color filter. The light is transmitted to the outside. For this reason, the light of the first color, the second color, and the third color is respectively emitted from the colored portion regions where the first color filter 17r, the second color filter 17g, and the third color filter 17b are arranged. Only the amount of reflected light corresponding to the image signal is emitted.

  In this way, the first color, the second color, and the third color are emitted from each pixel region P at a rate corresponding to the image signal. These lights are observed with additive color mixing. For this reason, the reflective display 1 can perform color display using each pixel region P as a display unit.

[Example 1]
As shown in FIG. 3, Example 1 is a reflective display 1 having the color filter 17 of the above embodiment, and each sub-pixel size is wX × wY = 170 μm × 170 μm, and the width of the color filter is This is an example of Lx × Ly = 150 μm × 150 μm. Example 1 of the reflective display 1 was manufactured as follows. A second electrode layer 14 made of indium tin oxide (ITO) and a reflective display layer 13 made of an electrophoretic display medium are laminated in this order on a light-transmitting substrate 15 made of PET. A laminate was formed. The thickness of the second electrode layer 14 was 0.1 μm, and the refractive index was 1.70. The reflective display layer had a thickness of 25 μm and a refractive index of 1.65.

  Thereafter, a first electrode layer 11 made of amorphous silicon as a semiconductor and an aluminum titanium alloy as a wiring was formed on a base material 10 made of glass. A reflective display layer 13 was bonded onto the first electrode layer 11 through an adhesive layer 12 formed of an acrylic adhesive.

  The reflectance of the used reflective display layer 13 was measured with a spectrocolorimeter CM-700d (trade name: manufactured by Konica Minolta Optics Co., Ltd.) under the conditions of a double field of view and a D65 light source, and displayed white. The white reflectance at the time was 44.5%, and the black reflectance when black was displayed was 2.1%.

  A coating liquid for forming the ink receiving layer 16 is applied on the light-transmitting substrate 15 in this state by a die coater, and then the coating film is dried to thereby receive an ink having an average film thickness of 8 μm. Layer 16 was formed. As a material for the coating liquid for forming the ink receiving layer 16, a mixed liquid of urethane resin, toluene, water, and IPA was used. A vacuum dryer was used for drying.

  The first electrode layer 11 was formed so that the size of each sub-pixel region in the pixel region P was 170 μm in the X direction width wX and 170 μm in the Y direction width wY.

  In this embodiment, the ink that forms the color filter layer 17 is red (hereinafter, R) for the first color, green (hereinafter, G) for the second color, and blue (hereinafter, B) for the third color. Was used. That is, an R ink (G ink, B ink) for inkjet printing was produced by mixing a pigment of R (G, B) with a colorant mixed with a binder resin, a dispersant, and a solvent. The first color, the second color, and the third color were manufactured with a weight of 7% pigment, 22% acrylic resin as binder resin, 3% dispersion, and 68% solvent mixture based on the ink weight. As the ink jet printing apparatus, an ink jet printing apparatus equipped with an ink jet head of 6 pl and 600 dpi (600 dots per 2.54 cm) of KJ4A-AA manufactured by Kyocera Corporation was used.

  A color filter printing method will be described. As shown in FIG. 5, 45 droplets of 6 pl were separately ejected within a range of 150 μm square with respect to one pixel region with the pixel region as the center to form a colored region as shown in FIG. The coated ink was dried at 80 ° C. for 5 minutes by a heat dryer. Thereby, the color filter layer 17 was formed.

  The thickness of the color filter was measured to 150 μm in length with a fully automatic fine shape measuring instrument ET4000A manufactured by Kosaka Laboratory Ltd. along A-A ′ of FIG. The ten-point average roughness is calculated as the sum of the average value of the altitude at the peak from the highest to the fifth from the center line and the average value of the altitude at the bottom from the deepest to the fifth from the center line. And formation of irregularities was observed. The area ratio of the color filter to the pixel region was 65%.

  Thus, the reflective display 1 of Example 1 of the above embodiment was manufactured.

[Example 2]
In this example, each sub-pixel size is 170 μm × 170 μm, and the X and Y widths of the color filters 17r, 17g, and 17b are 155 μm × 155 μm. The first color was red (hereinafter R), the second color was green (G), and the third color was blue (B). 1st color, 2nd color and 3rd color are 8% pigment based on ink weight, 20% acrylic resin as binder resin, 8% polymethyl methacrylate resin having an average diameter of 1 μm as light scattering particles, 4% dispersion material The solvent mixture was prepared at a weight of 60%. Other than that, it manufactured similarly to the said Example 1, and formation of the unevenness | corrugation was recognized.

[Comparative example]
Comparative example 1 is an example of the reflective display 100 of the comparative example when each sub-pixel size is 170 μm × 170 μm. The widths of the first color filter, the second color filter, and the third color filter were set to 155 μm × 155 μm, and they were produced by a reverse printing method. The film thickness of each color filter was 1.3 μm, the ten-point average roughness of the color filter was only 0.05 μm, and no irregularities were observed. Other than that was manufactured like the said Example 1. FIG.

[Evaluation]
With respect to the antireflection effect, the glossiness at an angle of 60 degrees was measured using a gloss meter GP-200 type manufactured by Murakami Color Research Laboratory Co., Ltd. The higher the glossiness, the smaller the reflection, and the lower the glossiness, the greater the scattering and the less reflection.

  The glossiness of Example 1 is 32.7, the glossiness of Example 2 is 18.5, and the glossiness of the comparative example is 72.3. Compared with the comparative example, the embodiment of the present invention has a sufficient antireflection effect. I was able to do it. As described above, the present invention can provide an antireflection effect by forming irregularities on the color filter by an inkjet method or the like.

  The present invention is useful for a display device such as a reflective display device.

1 Reflective display (reflective display)
DESCRIPTION OF SYMBOLS 10 Base material 11 1st electrode layer 11r 1st color subpixel electrode 11g 2nd color subpixel electrode 11b 3rd color subpixel electrode 13 Reflective display layer 13a, 13b, 15a Surface 13R 1st subpixel area 13G Second sub-pixel region 13B Third sub-pixel region 14 Second electrode layer 15 Light transmissive substrate (substrate)
16 Ink Receiving Layer 17 Color Filter Layer 17r First Color Filter 17g Second Color Filter 17b Third Color Filter P Pixel Area WX Width of Pixel Area in X Direction wX Width of Sub Pixel Area in X Direction WY Y Direction of Pixel Area Width wY Width in the Y direction of the sub pixel area

Claims (5)

A plurality of drive pixel regions whose reflectance can be changed independently;
And a color filter layer having unevenness provided on the plurality of drive pixel regions.   The display device according to claim 1, wherein a ten-point average roughness of the unevenness of the color filter layer is 0.6 μm or more and 2.2 μm or less.   The unevenness of the color filter layer is such that an average interval between convex portions along two directions in which the plurality of drive pixels are arranged is 10 μm or more and 120 μm or less, and the color filter layer covers the drive pixel region. The display device according to claim 1, wherein an area ratio is 52% or more and 100% or less.   The display according to any one of claims 1 to 3, wherein the color filter layer includes inorganic fine particles or organic fine particles of acrylic resin, styrene resin, or melamine resin in a weight ratio of 5% to 20%. apparatus. A method for manufacturing the display device according to claim 1,
A method for manufacturing a display device, comprising a step of forming the color filter layer by an inkjet method.