JP6447503B2 - Reflective display device having a color filter - Google Patents

Description

  The present invention relates to a reflective display device including a color filter.

  A method using a color filter is generally used for colorizing a display. In the case of a transmissive liquid crystal color filter, a lattice-like frame called a black matrix is formed, and red (R), green (G), and blue (B) are arranged in each frame. In this case, in the backlight type display device, light is allowed to pass through the color filter from the back to display a color image. Therefore, for example, when a red display is desired to be captured, the light in the area of the R pixel is allowed to pass, and the light in the area of the other pixel is blocked. Further, by adjusting the amount of light passing through, it is possible to express from bright display to dark display. In the case of a self-luminous display device, the colored portion shines, and the amount of light can be adjusted by the applied voltage.

  On the other hand, in the case of a reflective display device, since an image is displayed by reflecting light from the outside, if a black matrix is used for the color filter, there is a drawback that the reflected light is reduced and the color display becomes unclear. Therefore, it is preferable to form a color filter without providing a black matrix.

  For example, in an electrophoretic display device, two-color display mainly including black and white display is mainstream due to its structure, but each pixel is composed of sub-pixels of three primary colors of red, green, and blue on the electrophoretic display layer. A display device that provides a color filter and performs multicolor display has been proposed (see, for example, Patent Document 1).

  On the other hand, even if it is referred to as multi-color display, there is sufficient use as long as it has a vivid color display that is not full-color but attracts people's eyes. When a reflective display device of red, green and blue colors is used for such applications, there are problems that the color display is dull and it is difficult to display bright white.

  Further, when three color filters of red, blue, and green are used, when three colors are displayed at the same time, an achromatic color is displayed due to additive mixing of the colors, and white is displayed. Therefore, it is necessary to balance the hue and saturation of the three colors. This is also true for two color filters. For example, when displaying white with two colors of red and cyan, it is necessary to balance the hue and saturation of red and cyan.

JP 2003-161964 A

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a reflective display device capable of performing bright and vivid color display.

A first invention includes a reflective display layer for displaying white and black, and a color filter having a pixel pattern corresponding to a pixel electrode pattern of the reflective display layer, and each pixel of the color filter is a colored pixel. a first sub-pixel of a first color, seen including only the second sub-pixel of a second color different color than the first color, the first color filter is a color filter, The first color is a red color whose hue angle is in the range of 0 degrees to 60 degrees, and the second color has a hue angle of 60 degrees or more from the hue angle of the first color. This is a reflection type display device having a yellowish green color in a range moved by 150 degrees or less .

Further, each pixel of the color filter is a reflective display device further comprises a third sub-pixel transparent.

Also, as a color filter, further comprising a second color filter, the second color filter, a first color, hue angle is the color of reddish in the range of 45 degrees -30 degrees, the second color, the hue angle is a bluish color in a first range of motion 210 degrees to 300 degrees from the hue angle of the color, the reflection type display layer, and a first color filter In the reflective display device, the second color filter is provided in a separate display area.

  According to the present invention, when the first display color is displayed when displaying in combination with the reflective display device by forming only two colored pixels having no complementary color relationship in each pixel of the color filter. (The reflective display layer of the subpixel of the first color is displayed in white) When the second display color is displayed (the reflective display layer of the subpixel of the second color is displayed in white), these When displayed as a third display color in which the two colors are mixed (the reflective display layer of the subpixels of the first color and the second color is displayed in white), it is a vivid color in either case. Can be displayed.

  In addition, according to the present invention, even when all the sub-pixels of the reflective display layer are displayed in white, color can be displayed, so that color display can be performed with high luminance and the eye catching effect is enhanced. be able to.

In addition, the hue relationship of two colors that are not complementary colors can be expressed by using a hue angle h representing a hue in the L ^* and C ^* h color systems. This value can be calculated by measuring the spectral spectrum of the colored pixels of the color filter. The hue angle h2 in the range moved from 60 degrees to 150 degrees or from 210 degrees to 300 degrees from the hue angle h1 of the first display color can be set as the second display color. . At this time, the values of L ^* and C ^* are not limited, but higher values are preferable because they are brighter and more vivid.

  At this time, if the hue of the second display color is in the hue moved from the hue of the first display color to a hue angle of less than 60 degrees or greater than 300 degrees and less than 360 degrees, the first hue The second hue is a close color. Then, as the first display color, for example, the reflective display layer color of the first color sub-pixel is displayed in white, the other sub-pixels are displayed in black, and the second color display color is the second color sub-pixel. When the color of the reflective layer is displayed as white and the other sub-pixels are displayed as black, the difference between the first display color and the second display color becomes difficult to understand, and substantially one type of color display color Only colors that combine black can be produced, and expressive power is reduced.

  Further, when the hue of the second display color is set in a range in which the hue angle moves from greater than 150 degrees to less than 210 degrees from the hue of the first display color, the first display color and the second display color are complementary colors. The hue of the third color, which is a relationship and is a display in which the first color sub-pixel and the second color sub-pixel are mixed and displayed in white, is achromatic gray, and what is vivid color display? Don't be.

  The color filter may further include an area without colored pixels, that is, a transparent third sub-pixel. One pixel can be composed of a first sub-pixel, a second sub-pixel, and a third sub-pixel.

  Also, as shown in FIG. 1, the first color is a red color in which the hue angle h1 is in the range of −30 degrees to 45 degrees, and the second hue angle h2 is the first hue angle. By using a blue color in the range of 210 degrees to 300 degrees from h1, it is possible to display red and blue that are easily noticed. The third subpixel can be a transparent resin layer or a gap. Since the first color and the second color are not in a complementary color relationship, a vivid color having the third hue can be displayed by mixing the colors. For red and blue, purple can be displayed. Of course, it is obvious that the same display can be performed even when the first color and the second color are reversed.

  The first color is a red color in which the hue angle h1 is in the range of 0 degrees or more and 60 degrees or less, and the second hue angle h2 is 60 degrees or more and 150 degrees from the first hue. By setting the color to a yellowish green color within the moving range, green, red, and yellow, which is a mixed color thereof, can be displayed. This is an image of a traffic light, and it is possible to express instructions such as warning for red, caution for yellow, and no problem for green. The third subpixel can be a transparent resin layer or a gap. Of course, it is obvious that the same display can be performed even when the first color and the second color are reversed.

  In addition, as shown in FIG. 2, the area for forming these two colors of pixels that are not in the complementary color relationship may be a part of the area (image display area) driven by the display device, or a plurality of areas may be provided. A plurality of color areas may be formed in a part of the area. That is, as shown in FIG. 2, both colored areas 1 and 2 and an area 3 for monochrome display can be formed. This makes it possible to use the color area portion for alerting and the monochrome area for displaying character information.

  According to the present invention, it is possible to provide a reflective display device that enables color display of three bright and bright color hues.

  In addition, when red and blue are used as display colors, it is possible to use, for example, easily switching between “warm” and “clawed” displays of a beverage vending machine. In addition, by using an electronic shelf label for a retail store and providing an area to be colored, it is possible to call attention and make sales information and product information stand out.

  When a display device that displays work instructions in a factory or the like using red, green, and yellow as display colors, it can be effectively used to represent the progress of a product process. For example, red is used when delivery is delayed or trouble occurs, yellow is used to call attention, and green is displayed when there is no problem. Of course, the present invention is not limited to this, and a color reflective display device can be used for various purposes.

FIG. 1 is an explanatory diagram of a first hue and a second hue. FIG. 2 is an example of display content. FIG. 3 is a side view for explaining a layer structure of a color filter or the like. FIG. 4 is a top view for explaining the pixels (color pixels) of the color filter.

  Hereinafter, the reflective display device according to the present embodiment will be described in detail.

  The reflective display device according to the present embodiment includes a reflective display layer that displays white and black, and a pixel pattern (a plurality of pixel electrodes 11) corresponding to the pattern of the pixel electrode 11 (a pattern of the plurality of pixel electrodes 11) of the reflective display layer. Color filters 16 and 17 having a pattern of a plurality of pixels consisting of the sub-pixels). The reflective display layer is a laminate in the range from the substrate 10 to the film layer 15 with a transparent electrode in FIG. Each pixel of the color filters 16 and 17 includes only the first sub-pixel indicating the first color and the second sub-pixel indicating the second color different from the first color as the colored pixels. . Each pixel of the color filters 16 and 17 further includes a transparent third sub-pixel.

The first color is a red color whose hue angle is in the range of −30 degrees to 45 degrees, and the second color has a hue angle of 210 degrees or more from the hue angle of the first color. It is a bluish color that is in the range of 300 degrees or less. The first color is a red color whose hue angle is in the range of 0 to 60 degrees, and the second color has a hue angle of 60 degrees from the hue angle of the first color. It is a yellowish green color in the range of moving 150 degrees or less. The hue angle of the second color is in a range moved from 60 degrees to 150 degrees or from 210 degrees to 300 degrees from the hue angle of the first color. The hue relationship between these two colors is the hue angle in the L ^* and C ^* h color system.

  Note that, as in the reflective display device illustrated in FIG. 2, the color filters 16 and 17 may include a first color filter and a second color filter. On the reflective display layer, the first color filter and the second color filter are provided in separate display areas. In this case, in the first color filter, the first color is a red color having a hue angle in a range of −30 degrees to 45 degrees, and the second color has a hue angle of the first color filter. In the second color filter, the first color of the first color is in the range of 0 degrees to 60 degrees in the second color filter. The second color may be a red-green color, and the second color may be a yellow-green color in a range in which the hue angle moves from 60 degrees to 150 degrees from the hue angle of the first color.

  Specifically, an electrophoretic display device will be described as an example of a reflective display device. In the electrophoretic display device shown in FIG. 3, an electrophoretic display layer 13 is formed on a substrate 10 having a plurality of pixel electrodes 11 arranged in a predetermined pattern on the surface via an adhesive layer 12. The pixel electrode 11 is connected to each switching element, and a positive and negative voltage can be applied between the pixel electrode 11 and the transparent electrode layer 14. The electrophoretic display layer 13 is a layer formed by fixing a plurality of microcapsules in which a dispersion medium in which electrophoretic particles are dispersed in a dispersion solvent is sealed with a binder resin.

  On the electrophoretic display layer 13, a film layer 15 with a transparent electrode, color filters 16 and 17, an adhesive layer 18, and a protective film 19 are sequentially laminated.

  Within each microcapsule shell of the electrophoretic display layer 13, two types of electrophoretic particles having different electric polarities are dispersed in a transparent dispersion solvent.

  A method for forming the color filters 16 and 17 will be described. As a method for forming the color filters 16 and 17, a printing method such as a photolithography method, a reversal printing method, or an ink jet method can be used. Among them, an ink jet method capable of printing on a substrate in a non-contact manner is used. preferable.

  The color filters 16 and 17 are printed on the film surface side (outside) of the transparent electrode-equipped film layer 15 by an inkjet method in an arrangement that matches the drive pattern of the reflective display device. At this time, in order to maintain ink retention, an ink receiving layer may be formed on the film surface side of the film layer 15 with a transparent electrode.

  For example, in the case of a reflective display pattern having a resolution of 150 ppi, the drive pattern has a pitch of 169 μm. At this time, when the color is expressed using the color filters 16 and 17, color display of one pixel is performed in the area 20 shown in FIG. 4 using a plurality of pixels corresponding to the drive pattern. Each pixel for performing color display of one pixel is composed of four areas 21 shown in FIG. 4 (each area 21 is a quarter of the area 20 in FIG. 4). It is defined as a pixel. The colored pixels of the color filters 16 and 17 are formed corresponding to the pitch of the sub-pixels. In this case, each sub-pixel is provided corresponding to the pattern of the pixel electrode 11. However, the size of each sub-pixel does not necessarily need to match the pattern size of the pixel electrode 11.

  Further, a color filter pattern is printed on the protective film 19, and the driving pattern (the pattern of the pixel electrode 11) and the pixel pattern (the sub-pixel pattern) are matched with each other on the color filter surface and the display device surface with high accuracy. The color filters 16 and 17 may be bonded to the protective film 19. At this time, after the transparent adhesive material is applied to the protective film 19, the color filters 16 and 17 may be formed on the transparent adhesive material.

  When forming sub-pixels by the inkjet method, the shape of the droplet is spherical, so if one sub-pixel is formed with a large droplet, it will be circular. Therefore, by forming one subpixel by arranging a plurality of small droplets, the colored region can be made closer to a square shape.

  Since the shape of the droplet is spherical, when the area of the sub-pixel is small, the shape of the sub-pixel is close to a circular shape. At that time, it is preferable to narrow the gap between the sub-pixels (colored pixels) of different colors so as not to mix the colors because the color development performance is improved.

  In this embodiment, an inkjet coating apparatus is used, an inkjet head having a plurality of nozzles is scanned relative to the pixel pattern, and inkjet ink is ejected and supplied to the substrate surface. That is, a color filter layer is formed. In this embodiment, an inkjet head having a plurality of nozzles is scanned relative to the pixel pattern. The scanning may be performed by moving the substrate, or the scanning may be performed by moving the inkjet head. Further, scanning may be performed by moving both the base material and the inkjet head.

  As a material of the colored ink in this embodiment, a color pigment, a resin, a dispersant, and a solvent are used. Further, fluorine may be added to impart liquid repellency. As the ink pigment, it is preferable to use two of the three types of red, green and blue. However, colors such as purple, yellow and orange may be used.

  Specific examples of the color pigment used as the colorant include 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, PigmentBlue 15, 15: 3, 15: 6, 16, 22, 29, 60, 64, PigmentGreen 7, 36, PigmentRed 20, 24, 86, 81 83, 93, 108, 109, 110, 117, 125, 137, 138, 139, 147, 148, 153, 154, 166, 168, 185, Pigment Orange 36, Pigment Violet 23, and the like. Not intended to be. Further, these color pigments may be used in combination of two or more in order to obtain a desired hue.

  As the resin (binder resin) of the material of the colored ink, casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin, etc. can be used, and depending on the relationship with the pigment Selected. An acrylic resin is preferred when heat resistance and light resistance are required.

  In order to improve the dispersibility of the dye in the solvent, a dispersant may be used. As the dispersant, examples of the nonionic surfactant include polyoxyethylene alkyl ethers and ionic surfactants. For example, sodium alkylbenzene sulfonate, poly fatty acid salt, fatty acid salt alkyl phosphate, tetraalkylammonium salt, and the like, as well as organic pigment derivatives and polyesters can be used. One type of dispersant may be used alone, or two or more types of dispersants may be mixed and used.

  As the solvent species used for the colored ink, those having an appropriate surface tension range of 35 mN / m or less in ink jet printing and a boiling point of 130 ° C. or more are preferable. The resin amount is preferably adjusted so that the viscosity of the ink is 4 mPa · s or more and 20 mPa · s or less. When the surface tension is 35 mN / m or more, the dot shape stability at the time of ink jet discharge is significantly adversely affected. When the boiling point is 130 ° C. or less, the drying property in the vicinity of the nozzle is remarkably increased. This is not preferable because it causes clogging and other defects. Specifically, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, 2-methoxyethyl acetate, 2-ethoxyethyl ether, 2- (2-ethoxy Ethoxy) ethanol, 2- (2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate, 2-phenoxyethanol, diethylene glycol dimethyl ether, etc. can be used. The solvent is not limited to these, and any solvent that satisfies the above requirements can be used. Moreover, you may mix and use 2 or more types of solvents as needed.

  After printing the ink, a drying process is performed to evaporate the solvent contained in the ink. The drying means used in the drying step may be any method of heating, air blowing, decompression, light irradiation, or electron beam irradiation, or two or more of these methods may be combined.

  After the ink is dried, the protective film 19 is pressure-bonded to protect the display device. The pressure to be applied at the time of pressure bonding is preferably a value in the range of 0.1 MPa to 0.8 MPa.

  The protective film 19 is preferably a transparent film on which a pressure-sensitive adhesive layer 18 of a transparent adhesive is formed. The thickness of the adhesive layer 18 is preferably 5 μm or more and 30 μm or less. When the thickness of the pressure-sensitive adhesive layer 18 is 5 μm or less, the color filters 16 and 17 and the protective film 19 are easily peeled off, and when the thickness is 30 μm or more, a problem that the transparency is lowered tends to occur. If the ink receiving layer that receives ink has an effect as an adhesive, the adhesive layer 18 of transparent adhesive may not be formed on the protective film 19.

A color difference meter was used to evaluate the display performance of the produced color electronic paper, and the measurement item was a reflective display. Further, as the degree of color saturation, color saturation ^{C = ((a *) 2} + (b *) 2) were calculated using ^1/2. The saturation of the display color is an achromatic color with no tint, and the saturation C = 0. When the degree of vividness of the color increases, the value of the saturation C also increases.

  For the calculation of saturation C, the electronic paper display pattern was measured in dark color. For example, when the first color is displayed in dark color, the dark color display indicates that the electronic paper display pattern of the sub-pixel corresponding to the first color is displayed in white and the electronic paper display pattern of the other sub-pixels is displayed. This is a display pattern method for displaying in black.

( Reference Example 1)
A method for producing a film color filter substrate will be described.
The surface of the polyethylene terephthalate (PET) film substrate cut to a size of 240 mm × 300 mm was washed with pure water and dried with air.

  The PET film substrate was placed on an ink jet printer, and alignment marks serving as marks at the time of bonding to the display of the reflective display device were printed at four predetermined locations on the PET film substrate. Next, a grid-like pattern was printed so that the color filter pixels and sub-pixels (colored pixels) were formed at positions where the relative positional relationship was known. The components of the ink used for printing were 5% pigment, 22% synthetic resin, 3% cyclohexanone, and 70% diethylene glycol dimethyl ether. Two types of inks, red and blue, were prepared using the pigments listed as the color pigments. As the pigment, red (PR254) and blue (PB15: 3) were used. The alignment mark printing ink was red.

  In the pixel in which the sub pixel shown in FIG. 4 is vertical × horizontal = 2 × 2, the interval between the colored pixels of the sub pixel is 200 μm. The amount of ink discharged was adjusted so that the diameter of one drop was 45 μm or more and 50 μm or less, so that one drop was 16 pl. A subpixel was formed with 5 × 5 ink droplets, and the shape of the subpixel was formed so that the width of the subpixel was 190 μm. As a red pixel (first pixel), a quarter of the area 16 is printed with red ink, and as a blue pixel (second pixel), a quarter of the area 17 is blue ink. The remainder was left as a void. As the ratio of the colored area in the sub-pixel, red and blue were 90%.

  Next, the PET film substrate on which the color filter layer was formed was heat-dried at 75 ° C. for 5 minutes using a heating device.

  A transparent acrylic adhesive with a thickness of 20 μm was attached to the surface of the PET film on which the color filter layer was formed, using a laminating apparatus. Then, the display device and the color filter base material (PET film) were aligned and pressure-bonded with a laminating device to produce a color display device. The pressure applied was 0.4 MPa. The pressing speed was 3 mm / sec.

By this method, the display performance of the produced color electronic paper was measured using a color difference meter. The apparatus used for the measurement is a spectral color difference meter NF333 manufactured by Nippon Denshoku Industries Co., Ltd. The measurement item was reflection measurement, the light source was a D65 light source, and the measurement was performed in the L ^* a ^* b ^* color system. Further, saturation C was calculated as the degree of color vividness. In a reflective display device, when a display panel is used, generally, if the saturation is 20 or more, it looks like an eye-catching vivid color. Therefore, each of the first color and the second color is evaluated as an evaluation. Saturation C is 20 in dark color display, mixed color display of the first color and the second color (sub-pixels of the first color and the second color are displayed in white, and other pixels are displayed in black). The above cases were judged as good. Including the sensory evaluation of the appearance, the first color, the second color, and the mixed color are evaluated as “excellent: ◯” when the saturation and sensory evaluation of the dark color display are both good, and the saturation or sensory evaluation In the case where the quality was inferior to “excellent”, “good: Δ” was judged as acceptable, and those with poor quality in chroma and sensory evaluation were judged as “defective: x”. The results are shown in Table 1.

First, a dark red display was performed using an electronic paper display pattern corresponding to the red color filter as a white display and an electronic paper pattern of other pixels including the pixels of the second color as a black display. The display performance was a * = 25, b * = 5, saturation C = 25.5, and hue angle h1 = 10 degrees. Next, the electronic paper pattern corresponding to the blue color filter pattern was displayed as white, and the other electronic paper patterns were displayed as saturation C = 21.4 and hue angle h2 = 250 black. As a result, the display became dark blue, and the display performance was a * = − 7.5, b * = − 20, and degrees. As a result, the color electronic paper produced in the present Reference Example 1 displayed red, blue, and even a mixed purple color that was vivid. At this time, the difference between the first hue angle h1 and the second hue angle h2 is 240 degrees.

( Reference Example 2)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. The hue of the ink was changed using the pigments mentioned as the color pigment. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 280 degrees. Each of the first color, the second color, and the mixed color is darkly displayed, and each display color is vividly displayed. The value of saturation C is good, and the sensory evaluation also determines that the color is good.

( Reference Example 3)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 210 degrees. The mixed color of the first color and the second color was a display lacking in vividness, but was not at a defective level.

( Reference Example 4)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 300 degrees. Although the hues of the first color and the second color were dark, the difference in hue between the two colors was clearly recognized.

(Example 5)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 100 degrees. Each of the first color, the second color, and the mixed color is darkly displayed, and each display color is vividly displayed. The value of saturation C is good, and the sensory evaluation also determines that the color is good.

(Example 6)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 120 degrees. Each of the first color, the second color, and the mixed color is darkly displayed, and each display color is vividly displayed. The value of saturation C is good, and the sensory evaluation also determines that the color is good.

(Example 7)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 60 degrees. Although the hues of the first color and the second color were dark, the difference in hue between the two colors was clearly recognized.

(Example 8)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 150 degrees. The mixed color of the first color and the second color was a display lacking in vividness, but was not at a defective level.

(Comparative Example 1)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 50 degrees. Since the hues of the first color and the second color are close to each other, the difference between the display colors is difficult to understand, and only one limited display color can be expressed as a substantial display color.

(Comparative Example 2)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 160 degrees. The mixed color display of the first color and the second color was achromatic gray, and a vivid color could not be displayed.

(Comparative Example 3)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring the display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 200 degrees. The mixed color display of the first color and the second color was achromatic gray, and a vivid color could not be displayed.

(Comparative Example 4)
A color filter was printed by inkjet printing in the same manner as in Reference Example 1 except that the hue of the ink used in Reference Example 1 was changed. As a result of measuring display performance in the same manner as in Reference Example 1, the difference between the first hue angle h1 and the second hue angle h2 was 310 degrees. Since the hues of the first color and the second color are close to each other, the difference between the display colors is difficult to understand, and only one substantial display color can be expressed.

Table 1 shows the results of Reference Example 1 to Reference Example 4, Example 5 to Example 8, and Comparative Examples 1 to 4. As a result of performing the evaluation by changing the relationship between the hue angles of the first color and the second color, the hue angle of the second color is 60 degrees or more and 150 degrees or less from the hue angle of the first color, or When it is in the range of 210 degrees or more and 300 degrees or less, vivid color display can be performed for the first color, the second color, and all the mixed colors thereof.

Example 9
A lattice-like pattern was printed on the display device substrate with an inkjet device. The components of the ink used for printing were 5% pigment, 23% synthetic resin, 2% cyclohexanone, and 70% diethylene glycol dimethyl ether. As the pigment, red (PR254 and PY139 were mixed at a weight ratio of 9 to 1) and green (PG58) were used.

  The interval between the colored pixels was 170 μm. The ink discharge amount was adjusted so that the diameter of one drop in the 170 μm frame was 55 μm or more and 60 μm or less to be 24 pl per drop. The subpixels were formed with 3 × 3 ink droplets, and the shape of the subpixels was formed so that the width of the subpixels was 190 μm. Different inks were printed in red and green respectively. Two-quarters of the pixels were printed with red ink and the remaining areas were printed with green ink. As a coloring area ratio in each sub-pixel, red and green were 85%.

  Next, the display device substrate on which the color filter layer was formed was heat-dried at 75 ° C. for 5 minutes using a heating device.

  A transparent film on which a transparent adhesive layer having a thickness of 25 μm was formed was attached to the color filter surface using a laminating apparatus.

By this method, the display performance of the produced color electronic paper was measured using a color difference meter. The apparatus used for the measurement is a spectral color difference meter NF333 manufactured by Nippon Denshoku Industries Co., Ltd. The measurement item is reflection measurement, and the light source is a D65 light source. First, the electronic paper display pattern corresponding to the red color filter was set to white display, and the other electronic paper patterns were set to black display. Then, a dark red color was displayed, indicating a ^* = 20, b ^* = 15, saturation C = 25, and hue angle h1 = 37 degrees. Next, the electronic paper pattern corresponding to the green color filter pattern was displayed as white, and the other electronic paper patterns were displayed as black. As a result, a dark green display was obtained, indicating a ^* = − 20, b ^* = 23, saturation C = 31, and hue angle h2 = 131 degrees. All the patterns of the electronic paper were displayed in white, and displayed in yellow in a mixed color of two colors. a ^* = − 2, b ^* = 30, and C = 30. With these three colors, a vivid color display device could be produced. At this time, the difference between the first hue angle h1 and the second hue angle h2 was 94 degrees. At this time, it was possible to display a vivid color for the dark color display of each of the first color and the second color and the display of the mixed color thereof.

  As described above, according to the present invention, any of the following effects can be obtained. In other words, by forming only two colored pixels not having a complementary color relationship in each pixel of the color filter, when displaying in combination with the reflective display device, the first display color is displayed (first When the second display color is displayed (the reflective display layer of the second color sub-pixel is displayed in white), the two colors are further displayed. Is displayed as a third display color (the reflective display layer of the subpixels of the first color and the second color is displayed in white), and in any case, it can be displayed as a vivid color it can.

  Further, even when all the sub-pixels of the reflective display layer are displayed in white, color can be displayed, so that color display can be performed with high luminance and the eye catching effect can be enhanced.

In addition, the hue relationship of two colors that are not complementary colors can be expressed by using a hue angle h representing a hue in the L ^* and C ^* h color systems. This value can be calculated by measuring the spectral spectrum of the colored pixels of the color filter. The hue angle h2 in the range moved from 60 degrees to 150 degrees or from 210 degrees to 300 degrees from the hue angle h1 of the first display color can be set as the second display color. . At this time, the values of L ^* and C ^* are not limited, but higher values are preferable because they are brighter and more vivid.

  The color filter may further include an area where there is no colored pixel, that is, a transparent third sub-pixel. One pixel can be composed of a first sub-pixel, a second sub-pixel, and a third sub-pixel.

  Also, as shown in FIG. 1, the first color is a red color in which the hue angle h1 is in the range of −30 degrees to 45 degrees, and the second hue angle h2 is the first hue angle. By using a blue color in the range of 210 degrees to 300 degrees from h1, it is possible to display red and blue that are easily noticed. The third subpixel can be a transparent resin layer or a gap. Since the first color and the second color are not in a complementary color relationship, a vivid color having the third hue can be displayed by mixing the colors. For red and blue, purple can be displayed. Of course, it is obvious that the same display can be performed even when the first color and the second color are reversed.

( Reference Example 10-18)
Furthermore, as the first color, a red color having a hue angle in a range of −30 degrees to 45 degrees, and a second color is blue in a range moved from 210 degrees to 300 degrees from the first hue angle. Using the colors of the system and hue angles outside these ranges, the dark color display of the first color and the second color and the display performance evaluation of these mixed colors were performed. Note that printing, display performance evaluation, and the like were performed in the same manner as in Reference Example 1 except that the hue of the ink was changed.
Specifically, as shown in Table 2, for Reference Examples 10 to 12, the red hue angle of the first color is −30 degrees, Reference Examples 13 to 15 are 0 degrees, and Reference Examples 16 to 18 are 45 degrees. The display performance was evaluated by adjusting the hue so that the hue angle of the second color was 210 degrees, 250 degrees, and 300 degrees from the first color, respectively.

In Reference Examples 10 to 18, the dark color display of each of the first color and the second color, the display of the mixed color indicate a vivid color, and the saturation also indicates a good value that humans feel vivid, The color display was also vivid. On the other hand, in Comparative Examples 5, 7, and 9, the hue of the third color in which the first color sub-pixel and the second color sub-pixel are displayed in white and mixedly displayed becomes an achromatic gray color. No indication was obtained. In Comparative Examples 6, 8, and 10, the first hue and the second hue are close to each other, and the difference between the first display color and the second display color is not known. As a result, only the combined display can be displayed, and the range that can be expressed in color is very limited.

  The first color is a red color in which the hue angle h1 is in the range of 0 degrees or more and 60 degrees or less, and the second hue angle h2 is 60 degrees or more and 150 degrees from the first hue. By setting the yellow-green color within the range that has moved below, green, red, and yellow, which is a mixed color thereof, can be displayed. In this red hue range, when the hue angle of the second color is in the range of 60 to 150 degrees, all the display colors of the first color, the second color, and the third color (mixed color) are human. It was possible to display with a display color that can be recognized as vivid. This is an image of a traffic light, and it is possible to express instructions such as warning for red, caution for yellow, and no problem for green. The third subpixel can be a transparent resin layer or a gap. Of course, it is obvious that the same display can be performed even when the first color and the second color are reversed.

  In addition, as shown in FIG. 2, the area for forming these two colors of pixels that are not in the complementary color relationship may be a part of the area (image display area) driven by the display device, or a plurality of areas may be provided. A plurality of color areas may be formed in a part of the area. That is, as shown in FIG. 2, both colored areas 1 and 2 and an area 3 for monochrome display can be formed. This makes it possible to use the color area portion for alerting and the monochrome area for displaying character information.

  In addition, it is possible to provide a reflective display device that enables color display with three bright and bright color hues.

  In addition, when red and blue are used as display colors, it is possible to use, for example, easily switching between “warm” and “clawed” displays of a beverage vending machine. In addition, by using an electronic shelf label for a retail store and providing an area to be colored, it is possible to call attention and make sales information and product information stand out.

  Further, when a display device that displays a work instruction sheet in a factory or the like using red, green, and yellow as display colors, it can be effectively used to represent the progress of a product process. For example, red is used when delivery is delayed or trouble occurs, yellow is used to call attention, and green is displayed when there is no problem. Of course, the present invention is not limited to this, and a color reflective display device can be used for various purposes.

  The present invention can be used in a reflective display device including a color filter.

1 Color content area (displays the background in the first display color)
2 Color content area (displays the background in the second display color)
3 Black-and-white content area 10 Display device substrate 11 Pixel electrode 12 Adhesive layer 13 Electrophoretic display layer 14 Transparent electrode layer 15 Film layer with transparent electrode 16 Color filter (colored pixel of the first color)
17 Color filter (colored pixels of the second color)
18 Adhesive layer 19 Protective film 20 Pixel area (4 sub-pixels)
21 Sub-pixel area

Claims (3)

A reflective display device,
A reflective display layer for displaying white and black;
A color filter having a pixel pattern corresponding to the pattern of the pixel electrode of the reflective display layer,
Each pixel of the color filter, a colored pixel, a first sub-pixel of a first color, unrealized only the second sub-pixel of a second color different color from the first color ,
The first color filter, which is the color filter,
The first color is a red color having a hue angle in a range of 0 degrees to 60 degrees,
The second color is a yellowish green color whose hue angle is in a range moved from 60 degrees to 150 degrees from the hue angle of the first color.
Reflective display device. The reflective display device according to claim 1, wherein each pixel of the color filter further includes a transparent third sub-pixel. As the color filter, further comprising a second color filter,
In the second color filter, the first color is a red color having a hue angle in a range of −30 degrees to 45 degrees, and the second color has a hue angle of the first color. A blue-colored color in a range moved from 210 degrees to 300 degrees from the hue angle of one color ,
Prior Symbol reflective display layer, the first color filter and the second color filter is provided in a separate display area, the reflection type display device according to claim 1 or 2.