JP5961975B2 - Color filter for electronic paper and electronic paper - Google Patents

Description

  The present invention relates to a color filter for a reflective display device and a reflective display device capable of performing color display with high light utilization efficiency, hardly causing mixed color display, and good brightness and vividness. is there.

  In recent years, various flat type display devices such as electronic paper and liquid crystal display devices have been developed. Such a display device is provided with a backlight on the back surface, and a transmissive display device that controls light emission by a display panel, and a reflective display that controls reflected light of ambient illumination (hereinafter also referred to as “ambient light”). Broadly divided into devices. Among them, the reflection type display device has been applied because it has excellent characteristics such as low power consumption, eye fatigue, and good visibility under direct sunlight.

  In the above-described reflective display device, when performing color image display, a color filter having a plurality of colored layers is usually combined with a reflective display device member capable of performing white display and black display. Used. In addition, in such a reflective display device, a white color is displayed using a member for a reflective display device, ambient light is reflected, and the reflected light is transmitted through a color filter, thereby displaying a desired color image. It is what is said.

  Here, in the color filter used in the transmissive display device described above, a light-shielding portion having a predetermined pattern is formed in a region other than the pixel portion in order to improve the contrast of the display image of the transmissive display device. However, when the color filter having the above-described light-shielding portion is used in a reflective display device, the ambient light incident by the light-shielding portion of the color filter is absorbed, and as a result, the white display reflectance of the reflective display device is increased. Since it decreases, there is a problem that the light utilization efficiency decreases.

JP 2001-125514 A

K. Akamatsu, et al. SID 11 DIGEST (pp 198-201, 2011)

In order to improve the light utilization efficiency of the reflective display device, a reflective display device having a color filter that does not have a light shielding portion has been recently proposed (Patent Document 1). A clear guideline has not yet been established for the design of a color filter that does not have a light shielding portion.
For this reason, in the reflective display device including the color filter, it is difficult to achieve sufficient display characteristics such as brightness and vividness of color display, and display defects such as color mixing occur. There is.

  Accordingly, the present invention provides a color filter for a reflective display device, and a reflective display device that can perform color display with high brightness and vividness with high light utilization efficiency, less color mixing of color display. The main purpose is to provide

  As a result of intensive studies to solve the above problems, the present inventors have found that in the reflective display device, the display element in the display layer is included in the sub-pixel region corresponding to one counter electrode. It has been found as a knowledge that there exists a reverse drive region that is driven in reverse to the drive by the one counter electrode. The present invention has been made based on such knowledge.

The present invention includes a counter electrode substrate having a counter substrate and a counter electrode formed in a pattern on the counter substrate, and a reflection layer used in a reflective display device together with a display layer containing a display element that performs white display and black display. A color filter for a type display device, comprising: a transparent substrate; a plurality of sub-pixels provided on the transparent substrate; and a space portion provided between the sub-pixels, wherein the width of the space portion is A color filter for a reflective display device characterized by satisfying the following relational expression (1).
S> 2X (relational expression (1))
(In the relational expression (1), S is the width of the space portion, X is a subpixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. (This is the maximum value of the width of the reverse drive area that performs reverse drive.)

  According to the present invention, when the width of the space portion satisfies the relational expression (1), when used in a reflective display device, it is possible to perform color display having good brightness and vividness. A color filter for a type display device can be obtained.

In the present invention, it is preferable that the width of the space portion satisfies the following relational expression (2).
S> 2X + Y + Z1 + Z2 (relational expression (2))
(In the relational expression (2), S is the width of the space portion, X is a sub-pixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. The maximum value of the width of the reverse drive region that performs reverse driving, Y is the maximum value of the bonding deviation of the color filter for the reflective display device and the display layer, and Z1 is the total pitch shift of the color filter for the reflective display device (Z2 is the maximum value of the total pitch deviation of the counter electrode substrate).
Since the width of the space portion includes a distance corresponding to Y, Z1, and Z2, it is possible to suitably prevent the fitting displacement in the reflective display device using the color filter for the reflective display device of the present invention. It becomes.

  The present invention includes a counter electrode substrate having the above-described color filter for a reflective display device, a counter substrate, and a counter electrode formed in a pattern on the counter substrate, the color filter for the reflective display device, and a counter electrode. It has a display layer which is arranged between electrode substrates and has a display element for performing white display and black display, and a transparent electrode which is arranged on the reflective filter side color filter side of the display layer. A reflective display device is provided.

  According to the present invention, by having the above-described color filter for a reflective display device, a reflective display device capable of performing color display with good brightness and vividness can be provided.

  ADVANTAGE OF THE INVENTION According to this invention, the color filter for reflection type display apparatuses which can perform the color display which has the high brightness and the vividness with high utilization efficiency of light, color mixture of color display does not occur easily, and a reflection type display apparatus The effect that it can be provided is produced.

It is a schematic sectional drawing which shows an example of the reflection type display apparatus of this invention. It is the schematic which shows an example of the color filter for reflection type display apparatuses of this invention. It is a figure explaining the behavior of the display element in a reflection type display apparatus. It is a figure explaining the behavior of the display element in a reflection type display apparatus. It is a figure explaining the width | variety of the space part in the color filter for reflection type display apparatuses. It is a figure explaining the width | variety of the space part in the color filter for reflection type display apparatuses of this invention. It is a schematic plan view which shows an example of the counter electrode board | substrate used for the reflection type display apparatus of this invention.

  The color filter for a reflective display device and the reflective display device of the present invention will be described below.

A. First, a color filter for a reflective display device according to the present invention (hereinafter may be simply referred to as a color filter) will be described.
The color filter of the present invention is applied to a reflective display device together with a counter electrode substrate having a counter substrate and a counter electrode formed in a pattern on the counter substrate, and a display layer containing a display element that performs white display and black display. A transparent substrate, a plurality of subpixels provided on the transparent substrate, and a space provided between the subpixels, the width of the space being expressed by the following relational expression: (1) is satisfied.
S> 2X (relational expression (1))
(In the relational expression (1), S is the width of the space portion, X is a subpixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. (This is the maximum value of the width of the reverse drive area that performs reverse drive.)

  FIG. 1 is a schematic cross-sectional view showing an example of a reflective display device. As illustrated in FIG. 1, the color filter 10 of the present invention includes a counter substrate 21 and a counter electrode substrate 20 having a counter electrode 22 formed in a pattern on the counter substrate 21, and a display that performs white display and black display. The reflective display device 100 is used together with the display layer 30 having elements. Moreover, it has the transparent electrode 4 normally. In FIG. 1, a display layer 30 as a display element disperses a microcapsule 31, black particles 32 b and white particles 32 w charged in different charges, and black particles 32 b and white particles 32 w. An example of a display medium layer including a microcapsule type display medium 33 having a dispersion medium to be used is shown.

2A is a schematic plan view showing an example of the color filter of the present invention, and FIG. 2B is a cross-sectional view taken along line AA of FIG. As illustrated in FIGS. 2A and 2B, the color filter 10 of the present invention includes a transparent substrate 1 and a plurality of subpixels 2 provided on the transparent substrate 1 (in FIG. 2, red subpixels). 2R, white subpixel 2W, blue subpixel 2B, and green subpixel 2G), and a space 3 provided between the subpixels 2. Moreover, as illustrated in FIG. 1, an overcoat layer 5 or the like is formed as necessary.
The present invention is greatly characterized in that the width of the space portion 3 satisfies the relational expression (1).

  According to the present invention, when the width of the space portion satisfies the relational expression (1), a color capable of performing color display having good brightness and vividness when used in a reflective display device. It can be a filter.

  As described above, no clear guideline has been found for the design of a color filter that does not have a light-shielding portion. Therefore, in a reflective display device that includes a color filter that does not have a light-shielding portion, color brightness In addition, it is difficult to obtain desired display characteristics such as vividness, and there is a problem that display defects such as mixed color display occur.

As a result of intensive studies to solve the above problems, the present inventors have found that in the reflective display device, the display element in the display layer is included in the sub-pixel region corresponding to one counter electrode. However, the present inventors have found out that there exists a reverse drive region that is driven in reverse to the drive by the one counter electrode.
Specifically, as shown in FIG. 3, among the counter electrodes 22α, 22β, and 22γ, when the black display is performed using the counter electrodes 22α and 22γ and the white display is performed using the counter electrode 22β, the counter electrode 22α , 22γ, white particles 32w of the subpixel regions Vα, Vγ of the display layer 30 are directed to the observer (transparent electrode 4), black particles 32b are directed to the counter electrodes 22α, 22γ, and subpixels corresponding to the counter electrode 22β. In the region Vβ, the white particles 32w of the display layer 30 located in the region where the counter electrode 22β is formed move to the transparent electrode 4 side, and the black particles 32b move to the counter electrode 22β side, but near the boundary of the sub-pixel region Vβ. As a result, it was found that some of the black particles 32b positioned moved to the counter electrode 22β side, and some of the white particles 32w moved to the transparent electrode 4 side.
Note that FIG. 3 is a diagram for explaining the behavior of the display element in the reflective display device, and reference numerals that are not described can be the same as those in FIG.

  The reason why the display element is reversely driven is not clear, but is presumed as follows. That is, in a reflective display device, a display layer is provided between a counter electrode formed in a pattern and a transparent electrode, and an electric field applied between each counter electrode and the transparent electrode is changed according to display information. Thus, display is performed by driving the display element in the display layer located in the region where each counter electrode is formed. In such a reflective display device, since display is performed by moving the display element, etc., the display layer needs to have a certain thickness, and each counter electrode and the transparent electrode need a predetermined interval. . Since there is a predetermined interval between the electrodes in this way, a part of the electric field generated between each counter electrode and the transparent electrode diffuses to become a leakage electric field leaking from the region where the counter electrode is formed. It is presumed that this leakage electric field affects the display element in the display layer located in the vicinity of between the counter electrodes. Therefore, it is presumed that a part of the display element in the display layer located at the boundary of the subpixel region of each counter electrode exhibits reverse driving due to the influence of the leakage electric field of the other counter electrode adjacent thereto.

Moreover, it is estimated that the influence of the above-described leakage electric field varies depending on the type of display element. For example, since the display medium used for electronic paper uses two different colored materials of white and black, it is presumed that the influence of the leakage electric field on the charged materials of the respective colors is different. In the case illustrated in FIG. 3, since the influence of the leakage electric field on the black particles 32b is stronger among the black particles 32b and the white particles 32w, the black particles 32b located in the region Vβ corresponding to the counter electrode 22β. It is presumed that reverse driving was caused by the movement of.
As described above, the influence of the leakage electric field is presumed to be different depending on the type of the display element and the charge amount. Therefore, as illustrated in FIG. . Note that FIG. 4 is a diagram for explaining the behavior of the display element in the reflective display device, and reference numerals that are not described can be the same as those in FIG.

Based on the above knowledge, the present inventors have found that the display defect of the reflective display device described above is caused by the fact that the reverse drive area of the display element in the display layer is observed by the observer through the sub-pixels of the color filter. I found it. Further, by disposing the color filter space portion at a position corresponding to the reverse drive area included in the two adjacent sub-pixel areas, it is possible to prevent the above-described display failure of the reflective display device, that is, the color filter. It was found that the width of the space portion should satisfy the following relational expression (1 ′).
S ≧ 2X (relational expression (1 ′))
(In the relational expression (1 ′), S is the width of the space portion, X is the sub-pixel region corresponding to the counter electrode of one of the reflective display devices, and the display element in the display layer is the one counter. (This is the maximum value of the width of the reverse drive area that is driven in reverse to the drive by the electrode.)

Here, as illustrated in FIG. 5, when the width S of the space portion 3 is equal to the maximum value 2X of the width of the reverse drive region included in the two adjacent sub-pixel regions V, that is, S = 2X. In order to prevent display defects due to the reverse drive described above, the positions of the color filter 10, the display layer 30, and the counter electrode substrate 20 need to be performed with high accuracy. However, in the current method for manufacturing a reflective display device, there is a problem that fitting displacement is likely to occur, which causes mixed color display. In addition, there is a concern that the manufacturing efficiency when manufacturing the reflective display device is significantly reduced.
Therefore, as shown in FIG. 6, the inventors set the width S of the space portion 3 to be larger than the maximum value 2X of the width of the reverse drive region included in the two adjacent sub-pixel regions V, that is, By satisfying the relational expression (1), it has been found that both the display defect due to the leakage electric field and the display defect due to the fitting displacement can be prevented, and the present invention has been completed.
5 and 6 are diagrams for explaining the space width of the color filter, and reference numerals that are not described can be the same as those in FIGS. 1 and 3 and the like, and thus description thereof is omitted here. .

As described above, the present invention is greatly characterized in that the above 2X is defined as the lower limit of the width of the space portion of the color filter.
Details of the color filter of the present invention will be described below.

1. Space part The space part in this invention is demonstrated. The space portion is provided between the sub-pixels. In general, a colored member such as a light shielding portion or a colored layer is not formed in the space portion.

The space part in this invention has the big characteristic in the width satisfy | filling following relational expression (1).
S> 2X (relational expression (1))
(In the relational expression (1), S is the width of the space portion, X is a subpixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. (This is the maximum value of the width of the reverse drive area that performs reverse drive.)

  Note that the subpixel region in the present invention, as illustrated in FIG. 7, is a counter subpixel region having one side from the center of the counter electrode 22 of the counter electrode substrate 20 to the center of another adjacent counter electrode 22. A region of the display layer of the reflective display device facing U and a region of the reflective display device including the display layer, and “a subpixel region corresponding to one counter electrode” refers to one counter electrode It refers to a sub-pixel region that is opposed to the opposing sub-pixel region.

X is appropriately determined depending on the counter electrode substrate used together with the color filter of the present invention, the display layer, and the like, but is usually 20 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less. The lower limit of X may be 0 μm, but is usually about 2 μm.
In addition, X in this invention can be prescribed | regulated as follows, for example.
First, the width of the reverse drive area is obtained as follows.
A counter electrode substrate (TFT substrate) having a width of the counter subpixel region of 150 μm, a transparent electrode made of an ITO film, and formed between the counter electrode and the transparent electrode. As a display medium, white reflectance is 42%, black An evaluation reflective display device member containing a microcapsule type electrophoretic material manufactured by E-ink Corporation having a reflectance of 3% and having a display medium layer having a thickness of 100 μm is prepared.
Next, using the reflective display device for evaluation, white display is performed using an arbitrary counter electrode, and white display corresponding to one counter electrode when black display is performed using another counter electrode. The width of the display part is measured by observing with a microscope. The width of the reverse drive region can be calculated from the width of the counter subpixel region and the width of the white display portion.
In this way, in the evaluation reflective display device member, the widths of the reverse drive regions at any nine positions are obtained, and the largest value is defined as X.

As the width of the space portion, it is preferable that the following relational expression (2) is satisfied.
S> 2X + Y + Z1 + Z2 (relational expression (2))
(In the relational expression (2), S is the width of the space portion, X is a sub-pixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. The maximum value of the width of the reverse drive region that performs reverse driving, Y is the maximum value of the bonding deviation of the color filter for the reflective display device and the display layer, and Z1 is the total pitch shift of the color filter for the reflective display device (Z2 is the maximum value of the total pitch deviation of the counter electrode substrate).
The cause of misalignment of the reflective display device is large, and includes the misalignment of the color filter and display layer, the total pitch shift of the color filter, and the total pitch shift of the counter electrode substrate. Is a width including a distance corresponding to Y, Z1, and Z2, it is possible to make the reflective display device using the color filter of the present invention more excellent in display performance.

The value of Y is appropriately determined depending on the size of the color filter and the display layer, the accuracy of the apparatus used for bonding, etc., but is usually 20 μm or less, more preferably within 10 μm or less, particularly Preferably it exists in the range of 5 micrometers or less.
In addition, Y in this invention can be prescribed | regulated as follows, for example.
A transparent substrate made of a PET film having a size of 200 mm × 200 mm and a thickness of 125 μm, a red subpixel, a green subpixel, a blue subpixel, and a colored layer provided on the transparent substrate and having a colored layer in an arbitrary pattern A color filter having no white subpixel and an alignment mark for bonding formed on the transparent substrate, and a display medium layer used for the evaluation reflective display device member described above are prepared. As the display medium layer of the evaluation reflective display device member, a display medium layer alignment mark previously formed is used.
Next, the color filter and the display medium layer are bonded together under the conditions of a temperature of 23 ° C. and a humidity of 45% using V-SE340aaH manufactured by Climb Products as a bonding apparatus. Next, the positional deviation between the alignment mark of the color filter and the alignment mark for the display medium layer is observed using a microscope and measured to obtain a bonding deviation.
Such measurement of bonding deviation is repeated five times or more using the same color filter and display medium layer, and the largest value of the obtained bonding deviation is defined as Y.

The value of Z1 is appropriately determined depending on the size of the color filter, the material of the transparent substrate, the formation method of the colored layer, etc., but is usually 20 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less. It is.
Note that the total pitch of the color filter refers to the distance indicated by z1 in FIG.
Further, Z in the present invention can be defined as follows, for example.
As a transparent substrate, a PET film having a size of 200 mm × 200 mm and a thickness of 125 μm is used. On the transparent substrate, a red subpixel, a green subpixel, a blue subpixel having a colored layer in an arbitrary pattern, and no colored layer are present. White subpixels are formed by photolithography printing under conditions of a temperature of 23 ° C. and a humidity of 45%.
By calculating the difference between the total pitch value of the color filter actually formed and the total pitch value of the color filter designed in advance, the total pitch deviation can be obtained.
Such total pitch deviation measurement is performed using five or more (a plurality of) color filters, and the largest value of the obtained total pitch deviation values is defined as Z1.
In the present invention, when an alignment mark is formed in the vicinity of the outermost subpixel (or CF subpixel region) of the color filter, the deviation between the position coordinate of the designed alignment mark and the position coordinate of the actual alignment mark. Can be treated as equivalent to Z1.

The value of Z2 is appropriately determined depending on the size of the counter electrode, the material of the counter electrode substrate, the method of forming the counter electrode, etc., but is usually 10 μm or less, more preferably 5 μm or less, and particularly preferably 1 μm. It is as follows.
The total pitch of the counter electrode substrate refers to a distance indicated by z2 in FIG.
Moreover, Z2 in this invention can be prescribed | regulated as follows, for example.
As the counter electrode substrate, non-alkali glass having a size of 200 mm × 200 mm and a thickness of 700 μm is used, and the counter electrode is formed in an arbitrary pattern on the counter electrode substrate by a photolithography / etching printing method at a temperature of 23 ° C. and a humidity of 45%. A counter electrode is formed under conditions.
By calculating the difference between the total pitch value of the counter electrode substrate actually formed and the total pitch value of the counter electrode substrate designed in advance, the total pitch deviation can be obtained.
Such total pitch deviation is measured using five or more (a plurality of) counter electrode substrates, and the largest value of the obtained total pitch deviation values is defined as Z2.
In the present invention, when the display layer alignment mark is formed in the vicinity of the outermost counter electrode (or counter subpixel region) of the counter electrode substrate, the position coordinates of the designed display layer alignment mark and the actual display are displayed. The maximum deviation from the position coordinates of the layer alignment mark can be handled in the same way as Z2.

In addition, the upper limit of the width of the space portion in the present invention is not particularly limited as long as a desired color display can be performed, but the width of the space portion preferably satisfies the following relational expression (3). .
(X × y) / {( x + S) × (y + S)} ≧ 105 2/150 2 = 0.49 ( equation (3)
(In the relational expression (3), S is the width of the space part, (x × y) is the area of the subpixel, and (x + S) × (y + S) is the area of the CF subpixel region.)
The width of the space portion satisfies the relational expression (3), that is, the ratio of the area of one subpixel to the area of one CF subpixel region is 105 × 105/150 × 150 = 0.49 or more. As a result, the NTSC ratio of the reflective display device using the color filter of the present invention can be set to 2% or more, and color display with good vividness can be performed. In the relational expression (3), x, y, and S indicate the distances shown in FIG. The CF sub-pixel region in the color filter is a region having one side from the center of the space portion to the center of another adjacent space portion, and indicates a region indicated by Q in FIG.

  The specific width of the space portion is adjusted so as to satisfy the above-described relational expression according to the use of the color filter and the like. In particular, the width of the space portion is preferably in the range of 20 μm to 50 μm, more preferably in the range of 20 μm to 40 μm, and particularly preferably in the range of 20 μm to 30 μm. This is because, when the width of the space portion is less than the above range, it may be difficult to suppress display defects due to reverse driving of the display element and fitting displacement of the reflective display device. On the other hand, when the width of the space portion exceeds the above range, the aperture ratio of the color filter becomes small, so that it is difficult to perform color display having desired brightness and vividness using the color filter of the present invention. This is because there is a risk of becoming.

  About the pattern shape of the said space part, it selects suitably according to the pattern shape of a subpixel.

2. Subpixel The subpixel in the present invention is provided on a transparent substrate. Further, in the present invention, normally, a red subpixel, a green subpixel, and a blue subpixel are provided, and a colored layer is formed in each color subpixel.
In the present invention, sub-pixels of necessary colors can be added as appropriate in addition to the sub-pixels of the color described above.

  In the present invention, as shown in FIGS. 2 (a) and 2 (b), in addition to the subpixels 2R, 2G, and 2B of each color having the above-described colored layer, It is preferable to have the white subpixel 2W which has an equivalent area and is not formed with a colored layer. This is because by having the white sub-pixel 2W, a color filter with higher light utilization efficiency can be obtained.

  The pattern shape of the sub-pixel used in the present invention is not particularly limited, and can be appropriately selected according to the use of the reflective display device in which the color filter of the present invention is used. Examples of such pattern shapes include a stripe type, a mosaic type, a triangle type, and a four-pixel arrangement type. At this time, the area of each colored layer is not particularly limited, and is appropriately adjusted according to the resolution of the reflective display device in which the color filter of the present invention is used.

  Examples of the material for the colored layer include pigments and other colorants and photosensitive resins, and specifically, the same as those used for the colored layer of a general color filter. The description in is omitted.

  The thickness of the colored layer used in the present invention is not particularly limited as long as a good image display can be performed when the color filter of the present invention is used in a reflective display device. Can be set within a range of 0.5 μm to 3.0 μm.

  The method for forming the colored layer is not particularly limited as long as the colored layer having a desired thickness can be formed without color mixing. As such a method, for example, a generally known method such as a photolithography method or a printing method can be used.

3. Transparent substrate The transparent substrate used for this invention will not be specifically limited if the colored layer mentioned above can be formed on the said transparent substrate.

  Such a transparent substrate can be the same as the transparent substrate used for a general color filter, specifically, quartz glass, alkali-free glass, soda lime glass, Pyrex (registered trademark) glass, synthetic glass Examples thereof include a transparent rigid material having no flexibility such as a quartz plate, or a transparent flexible material having flexibility such as a transparent resin film and an optical resin plate. In the present invention, a transparent resin film is particularly preferable. This is because the transparent resin film is inferior in dimensional stability as compared with glass or the like, and therefore, it is possible to exert a high effect of suppressing the deterioration of display characteristics by setting the width of the space portion as described above.

  Examples of the transparent resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyimide (PI), polyetheretherketone (PEEK), polycarbonate (PC), polyethylene ( PE), polypropylene (PP), polyphenylene sulfide (PPS), polyetherimide (PEI), cellulose triacetate (CTA), cyclic polyolefin (COP), polymethyl methacrylate (PMMA), polysulfone (PSF), polyamideimide (PAI) The film which consists of etc. can be mentioned. In the present invention, PET is particularly preferable.

  About the thickness of a transparent substrate, it is possible to select suitably according to the use of a color filter. For example, when the transparent substrate is a transparent resin film, it is preferably in the range of 50 μm to 250 μm, in particular in the range of 50 μm to 188 μm, particularly in the range of 50 μm to 125 μm.

4). Other Configurations The color filter of the present invention is not particularly limited as long as it has the above-described space portion, subpixel, and transparent substrate, and is necessary according to the type of reflective display device in which the color filter is used. Various configurations can be added as appropriate.

  In the present invention, the transparent electrode used in the reflective display device may be formed on the color filter. Hereinafter, the transparent electrode will be described.

(1) Transparent electrode The formation position of the transparent electrode used in the present invention is appropriately selected according to the type of the reflective display device used, and on the surface of the transparent substrate opposite to the subpixel side. It may be formed between the transparent substrate and the colored layer formed on the sub-pixels of each color, or may be formed on the colored layer. The transparent electrode may be formed directly on the transparent substrate or the colored layer, or may be formed via another layer.

  The material of the transparent electrode used in the present invention is not particularly limited as long as it is a conductive material capable of forming a transparent electrode. For example, indium tin oxide (ITO), indium zinc oxide (IZO), Conductive oxides such as tin oxide, zinc oxide, indium oxide, and aluminum zinc oxide (AZO), metals such as Au and Ni, conductive polymers such as polyaniline, polyacetylene, polyalkylthiophene derivatives, and polysilane derivatives are used. Among them, ITO is preferably used.

  The thickness of the transparent electrode used in the present invention is not particularly limited as long as it can function as a transparent electrode, but is preferably in the range of 15 nm to 200 nm. When the thickness of the transparent electrode is less than the above range, it is difficult to form the transparent electrode with a uniform thickness. When the thickness of the transparent electrode exceeds the above range, it is used for forming the transparent electrode. This is because the manufacturing cost increases because more time and materials are required.

  The method for forming the transparent electrode used in the present invention is not particularly limited as long as the transparent electrode can be formed with a desired thickness. As a method for forming such a transparent electrode, a general electrode film forming method can be used. For example, a PVD method such as a vacuum deposition method, a sputtering method, or an ion plating method, a CVD method, or a conductive paste The method of apply | coating etc. are mentioned. The transparent electrode may be formed on the entire surface of the underlying layer or substrate, or may be formed in a pattern on the underlying layer or substrate surface.

(2) Other Configurations The color filter of the present invention can have, for example, an overcoat layer provided to protect the colored layer, in addition to the configuration described above. Since the overcoat layer can be the same as a general one, description thereof is omitted here.

5. Color filter The size of the color filter of the present invention is appropriately selected depending on the application, but is preferably 1000 mm × 1000 mm or less, more preferably 300 mm × 300 mm or less, and particularly preferably 200 mm × 200 mm or less. When the size of the color filter is within the above range, the width of the space portion described above can be easily adjusted, and a color filter exhibiting better brightness and vividness can be obtained.
As a minimum of the size of a color filter, it can be about 10 mm x 10 mm, for example.

6). Reflective Display Device The color filter of the present invention is used in a reflective display device together with a counter electrode substrate and a display layer. Details of the reflective display device will be described in detail in the section “B. Reflective Display Device” described later.

B. Reflective Display Device Next, the reflective display device of the present invention will be described.
The reflective display device of the present invention includes the color filter described in the above-mentioned section “A. Color filter for reflective display device”, a counter substrate, and a counter electrode formed in a pattern on the counter substrate. A counter electrode substrate having a display layer disposed between the color filter and the counter electrode substrate and having a display element for performing white display and black display, and a transparent electrode disposed on the color filter side of the display layer. It is characterized by this.

  FIG. 1 is a schematic cross-sectional view showing an example of a reflective display device of the present invention. Since FIG. 1 has been described in the above-mentioned section “A. Color filter for reflection display device”, description thereof is omitted here.

According to the present invention, by having the above-described color filter for a reflective display device, a reflective display device capable of performing color display with good brightness and vividness can be provided.
Hereinafter, details of the reflective display device of the present invention will be described.

1. Color Filter The color filter according to the present invention has been described in the above-mentioned section “A. Color Filter for Reflective Display Device”, and thus description thereof is omitted here.

2. Next, the display layer in the present invention will be described. The display layer in the present invention contains a display element that performs white display and black display, and is disposed between the counter electrode substrate and the color filter.

The display layer in the present invention is not particularly limited as long as white display and black display can be performed, and can be appropriately selected depending on the type of the reflective display device of the present invention. For example, when the reflective display device is a reflective liquid crystal display device, a liquid crystal layer is used as the display layer. When the reflective display device is reflective electronic paper, a display medium layer is used as the display layer. It is done.
Hereinafter, each of the liquid crystal layer and the display medium layer will be described.

(1) Liquid crystal layer When the display layer in this invention is a liquid crystal layer, a liquid crystal material is used as a display element.
Since the liquid crystal material used for the liquid crystal layer, the thickness of the liquid crystal layer, and the like can be the same as those used for the liquid crystal layer of a general liquid crystal display device, description thereof is omitted here.

(2) Display medium layer When the display layer in this invention is a display medium layer, a display medium is used as a display element.
The display medium layer is not particularly limited as long as it can perform black display and white display, and is appropriately selected according to the display method of the reflective display layer device (electronic paper).
As a display method of electronic paper, known ones can be applied, for example, electrophoresis method, twist ball method, powder movement method (electronic powder fluid method, charged toner type method), liquid crystal display method, thermal method. (Coloring method, light scattering method), electrochromic method, electrowetting method, magnetophoresis method and the like. In the present invention, among them, the electrophoresis method is preferably used. This is because this method is in a practical stage and is a particle movement type, and thus it is possible to obtain an electronic paper that is less dependent on viewing angle and excellent in responsiveness.

The electrophoresis method uses an electrophoresis phenomenon in which charged particles dispersed in a solvent move between electrodes by an electric field. Examples of the electrophoresis method include a microcapsule method and a microcup method.
In the microcapsule method, charged white particles and black particles and a transparent dispersion medium in which these particles are dispersed are encapsulated in a microcapsule made of a transparent resin, and an electric field is applied to the white particles and the black particles. The black and white display or gradation is expressed by moving up and down.
In the microcup method, a dispersion medium colored with a dye and charged white particles are arranged in a cell partitioned by cup-shaped depressions (microcups), and the white particles are moved up and down by applying an electric field. Thus, white or the color of the dispersion medium is displayed.

  The configuration, material, and formation method of the display medium layer used in the present invention can be the same as those used for general electronic paper of each display method.

  The reflective display device of the present invention is preferably a microcapsule electronic paper. Hereinafter, a display medium layer when used in microcapsule electronic paper will be described as an example. As such a display medium layer, for example, a microcapsule in which a dispersion liquid composed of white particles, black particles, and a transparent dispersion medium is fixed with a binder resin can be used.

  Examples of the transparent dispersion medium include alcohol solvents, various esters, ketones, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, carboxylates, and other various oils. Or a mixture of these with a surfactant or the like can be used.

As the white particles, for example, white pigments such as titanium dioxide, zinc white, and antimony trioxide can be used. As the black particles, for example, black pigments such as aniline black, carbon black, and titanium black can be used. .
Further, if necessary, these pigments may be charged with electrolytes, surfactants, metal soaps, resins, rubbers, oils, varnishes, compound charge control agents, titanium-based coupling agents, aluminum-based coupling agents, A dispersant such as a silane coupling agent, a lubricant, a stabilizer and the like may be added.

  As a material for forming the wall film of the microcapsule, for example, a compound such as a gum arabic / gelatin composite film, a urethane resin, a urea resin, or a urea resin can be used.

  As the binder resin, those having good affinity for the wall film of the microcapsule and having insulating properties can be used, and examples thereof include polyethylene, chlorinated polyethylene, ethylene-vinyl acetate copolymer, silicone resin and the like. Can do.

  Such a display medium layer can be formed, for example, by applying an ink obtained by dispersing microcapsules in a binder resin.

  The thickness of the display medium layer is not particularly limited as long as the display medium can be driven to perform black display and white display. However, the thickness is within the range of 10 μm to 300 μm, and particularly within the range of 10 μm to 200 μm. It is preferably within the range of 10 μm to 100 μm. This is because if the thickness of the display medium layer is less than the above range, the movement of the display medium may be hindered. If the thickness of the display medium layer exceeds the above range, an electric field may be applied between the electrodes. This is because the display medium may not be driven.

3. Counter electrode substrate The counter electrode substrate used in the present invention has a counter base material and a counter electrode formed on the counter base material.

(1) Counter electrode The counter electrode used in the present invention may be a pixel electrode layer formed so as to be orthogonal to the stripe pattern of the transparent electrode, and a plurality of TFT elements and pixels connected to the TFT elements. A TFT electrode layer having electrodes may be used. By using the former, a passive matrix reflective display device can be obtained, and by using the latter, an active matrix reflective display device can be obtained.

  Since the counter electrode can be the same as that used in a general reflection type display device, description thereof is omitted here.

(2) Counter substrate The counter substrate used in the present invention supports the counter electrode. Such a counter substrate is not particularly limited as long as it is generally used as a counter substrate of a reflective display device. For example, a glass plate, a plastic plate, and the like are preferable.

4). Transparent electrode The transparent electrode used for this invention is arrange | positioned on the opposite side to the counter electrode board | substrate side of a display medium layer.
Such a transparent electrode is not particularly limited as long as it can be disposed on the side opposite to the counter electrode substrate side of the display medium layer, and other layers such as a substrate for transparent electrode or the like directly on the display medium layer. It may be formed via a color filter or a color filter. Note that the transparent electrode substrate can be the same as the transparent substrate used in the color filter, and thus the description thereof is omitted here.
The transparent electrode can be the same as that described in the section “A. Color filter” described above, and thus the description thereof is omitted here.

5. Other Configurations The reflective display device of the present invention is not particularly limited as long as it has the above-described color filter, display layer, counter electrode substrate, and transparent electrode, and other necessary configurations are appropriately selected and added. Is possible.

As such a configuration, for example, when the reflective display device is a reflective electronic paper, the optical function layer for improving the visibility of the reflective electronic paper, and the scratches and dirt on the surface of the reflective electronic paper are prevented. For example, a surface protective layer for protecting the display medium layer from moisture and oxygen, and a touch panel layer for imparting a function that enables input of information by directly touching the screen to the reflective electronic paper. be able to. Note that all the layers described above are arranged on the sub-pixel side of the color filter or on the side opposite to the sub-pixel side.
In addition, about the structure mentioned above, since it can be set as the same as a general thing, description here is abbreviate | omitted.

  On the other hand, for example, when the reflective display device is a reflective liquid crystal display device, the touch panel and the polarizing plate described above can be used.

6). Reflective Display Device The white display reflectance of the reflective display device of the present invention is not particularly limited as long as a desired color display can be performed. When the reflection type display device is reflection type electronic paper, it is preferably 30% or more, particularly 35% or more, particularly 40% or more.
On the other hand, when the reflective display device is a reflective liquid crystal display device, it is preferably 30% or more, more preferably 35% or more, and particularly preferably 40% or more.
When the white reflectance of the reflective display device is within the above range, color display having good brightness can be performed.
The white reflectance of the reflection type display device can be obtained by, for example, measuring according to the standard configuration A of “Electronic Information Technology Industry Association Standard” EIAJ ED-2523.

The NTSC ratio of the reflective display device of the present invention is not particularly limited as long as a desired color display can be performed.
When the reflective display device is a reflective electronic paper, it is preferably 2% or more, more preferably 3% or more, and particularly preferably 5% or more.
On the other hand, when the reflective display device is a reflective liquid crystal display device, it is preferably 2% or more, more preferably 3% or more, and particularly preferably 5% or more.
When the NTSC ratio of the reflective display device is within the above range, color display with good vividness can be performed.
The NTSC ratio of the reflective display device is determined by measuring the reflectance of the reflective display device in accordance with, for example, the standard configuration A of “Electronic Information Technology Industry Association Standard” EIAJ ED-2523, and with respect to the color reproduction region of the NTSC standard. The ratio of the color reproduction region actually measured by the reflective display device can be obtained.

  About the manufacturing method of the reflection type display apparatus of this invention, it can be made to be the same as that of the manufacturing method of a general reflection type display apparatus.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

The reflectivity of the reflective display device was measured in accordance with the standard configuration A of “EIAJ ED-2523 Standard of Electronic Information Technology Industries Association”. The illumination light source was D65.
In the following description, the white display of the reflective display device displays all the reflective display elements of the sub-pixels RGBW in white. For example, in the red display of the reflective display device, the reflective display element of the sub-pixel R is displayed in white, and the reflective display element of the sub-pixel GBW is displayed in black. Hereinafter, the NTSC ratio is the ratio of the color reproduction region actually measured by the reflective display device to the color reproduction region of the NTSC standard.

[Example 1]
<Production of member for reflection type display device>
As the counter electrode substrate, non-alkali glass having a size of 200 mm × 200 mm and a thickness of 700 μm is used, and the counter electrode is formed in an arbitrary pattern on the counter electrode substrate by a photolithography / etching printing method at a temperature of 23 ° C. and a humidity of 45%. A TFT substrate in which the width of the counter subpixel region formed under the conditions was 150 μm was prepared. An alignment mark for bonding was formed at a position 1 mm outside the counter subpixel region of the outermost counter electrode to form a display layer alignment mark.
The position coordinates of the alignment mark were measured using a dimension measuring machine (AMIC-1300, manufactured by Sokkia). The maximum value Z2 of the total pitch deviation was obtained from the measurement result and found to be 1 μm.
A microcapsule type electrophoretic material manufactured by E-ink Corporation having a white reflectance of 42% and a black reflectance of 3% is prepared as a reflective display medium of the reflective display device, and is arranged on the TFT substrate for reflection. A member for a mold display device was obtained. When X was determined, it was 5 μm.

<Design of color filter>
As described below, the maximum value Y of the bonding deviation between the color filter and the display layer and the maximum value Z of the total pitch deviation of the color filter were obtained.
Prepare a PET film (Toyobo, product name: A4100, film thickness: 125 μmt) with a size of 200 mm x 200 mm, and alignment mark for bonding at a position 1 mm outside the outermost CF subpixel area of the color filter Formed. The position coordinates of the alignment mark were measured using a dimension measuring machine (AMIC-1300, manufactured by Sokkia). The maximum value Z1 of the total pitch deviation was determined from the measurement results and found to be 5 μm.

  Alignment bonding is performed so that the alignment mark of the PET film and the alignment mark for the display layer overlap, and the position coordinates of each alignment mark are measured using a dimension measuring machine (manufactured by Sokkia Co., AMIC-1300). The maximum value Y of the deviation was determined to be 5 μm.

<Production of color filter>
As a color filter substrate, a PET film having a size of 200 mm × 200 mm (manufactured by Toyobo, product name: A4100, film thickness: 125 μmt) was prepared.
The sub-pixel pattern was arranged in a four-pixel arrangement shape of R, G, B, and W, and a colored layer was formed on the R, G, and B sub-pixels. The width of the space portion between the sub-pixels was 25 μm. As a result, a color filter was obtained.

<Production and Evaluation of Reflective Display Device>
Alignment bonding was performed so that the color filter and the pixels of the reflective display device member overlapped to produce a reflective display device.
The produced reflective display device displayed red, green, blue, white, and black. The NTSC ratio was 6.3% and the white reflectance was 28%, and a vivid color display was obtained by visual evaluation.

[Example 2]
As a result of color display with a reflective display device under the same conditions except that the width of the space portion of the color filter was set to 40 μm, the NTSC ratio was 3.0% and the white reflectance was 31%. became.

[Comparative Example 1]
As a result of color display on the reflective display device under the same conditions except that the width of the space portion of the color filter is set to 10 μm, a fitting displacement occurs between the reflective display device member and the color filter, and color mixing occurs in the color display. It was.

[Reference example]
Except that the width of the space part of the color filter is set to 50 μm, the color display on the reflective display device under the same conditions results in an NTSC ratio of 1.6% and a white reflectance of 38%. Was bright but could not display vivid colors.
In the reference example, although the relational expression (1) is satisfied, it is considered that the vivid color display cannot be performed because the area of the sub-pixel itself is reduced.

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2 ... Subpixel 3 ... Space part 4 ... Transparent electrode 10 ... Color filter 20 ... Counter electrode substrate 21 ... Counter substrate 22 ... Counter electrode 30 ... Display layer 100 ... Reflective display apparatus U ... Subpixel area | region

Claims (3)

A counter electrode substrate having a counter substrate and a counter electrode formed in a pattern on the counter substrate, and a color filter for electronic paper used for electronic paper performing white display and black display,
A transparent substrate;
A plurality of subpixels provided on the transparent substrate;
A space provided between the sub-pixels,
The color filter for electronic paper, wherein the width of the space portion satisfies the following relational expression (1) and is in the range of 25 μm to 50 μm .
S> 2X (relational expression (1))
(In the relational expression (1), S is the width of the space portion, X is a sub-pixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. (This is the maximum value of the width of the reverse drive area that performs reverse drive.) The color filter for electronic paper according to claim 1, wherein the width of the space portion satisfies the following relational expression (2).
S> 2X + Y + Z1 + Z2 (relational expression (2))
(In the relational expression (2), S is the width of the space portion, X is a sub-pixel region corresponding to one counter electrode, and the display element in the display layer is driven by the one counter electrode. The maximum value of the width of the reverse drive region that performs reverse driving, Y is the maximum value of the bonding deviation between the color filter for the reflective display device and the display layer, and Z1 is the total pitch deviation of the color filter for the reflective display device (Z2 is the maximum value of the total pitch deviation of the counter electrode substrate). The color filter for electronic paper according to claim 1 or 2,
A counter substrate having a counter substrate and a counter electrode formed in a pattern on the counter substrate;
A display layer having a display medium layer disposed between the color filter for the reflective display device and the counter electrode substrate and performing white display and black display;
An electronic paper comprising: a transparent electrode disposed on a color filter side of the reflective display device of the display layer.

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