JP5109305B2 - Image display medium - Google Patents

Description

  The present invention relates to an image display medium, and more particularly, to an image display medium having a simple and inexpensive configuration in which occurrence of a short circuit between electrodes is effectively prevented and the reliability of a display portion is high.

  In recent years, in addition to paper media and electronic display devices as image display media, the contents of both have been combined, and the display contents are electrically rewritten among display media that have the advantages of paper and retain visibility and portability. An image display medium called “electronic paper” or “digital paper” that can be used is attracting attention. That is, cards (for example, commuter pass, examination ticket, membership card, ID card, cash card, credit card, merchandise distribution tag, etc.) having a non-contact IC represented by RFID (RF tag) are widely used. Accordingly, there has been a growing demand for rewritable display of characters, graphics, and the like on these cards, so that there is a great demand for “electronic paper” and the like.

  As such an image display medium, a cut-out body of a predetermined shape is cut out from a pair of substrates (substrate with a thin-film electrode) each having a thin-film electrode formed on the entire surface, and a display material and an adhesive are respectively applied in a strip shape. It is known to have a structure in which a display layer is sandwiched between a pair of opposingly arranged substrates with thin film electrodes produced by bonding together.

  However, in the case of such an image display medium, since a pair of thin film electrodes are exposed at the end portion of the substrate, there is a problem that surface conduction is easily caused at the exposed portion and short-circuiting easily occurs. In particular, in a full-surface electrode-formed substrate on which a thin film electrode is formed on the entire surface, it has been extremely difficult to realize an end portion in which the thin film electrode is not exposed. Although short-circuiting due to surface conduction can be prevented by insulating and sealing the edge of the substrate, workability is poor because a sealing agent must be disposed on the front and back. In addition, short-circuiting can be prevented by patterning so that the thin-film electrode is not exposed at the end, but the cost has to be increased.

On the other hand, as a conventional image display medium, a technique for reliably preventing moisture from entering from each electrode terminal portion of the back electrode and the front electrode by taking out the electrode from one substrate through a through hole is known. (See Patent Document 1).
JP 2000-68051 A

  The present invention has been made in view of the above-described background art, and provides an image display medium having a simple and inexpensive configuration in which the occurrence of a short circuit between electrodes is effectively prevented and the reliability of a display portion is high. With the goal.

  In order to achieve the above object, according to the present invention, the following image display medium is provided.

[1] A first substrate laminate in which a first thin film electrode is formed on a first substrate and a plane smaller than the first substrate disposed opposite to the first substrate laminate. A second substrate stack in which a second thin film electrode smaller in plan than the first thin film electrode is formed on a second substrate; the first thin film electrode of the first substrate stack; And a display layer sandwiched between the second thin film electrode of the second substrate laminate, and the first and second thin film electrodes are formed on the entire surfaces of the first and second substrates. The display layer is smaller than the first thin film electrode in a plan view so that a horizontal distance can be maintained between the first thin film electrode and the second thin film electrode; and An image display medium, wherein the image display medium is formed larger in plan than the second thin film electrode.

[2] The image display medium according to [1], further comprising an adhesive layer between the display layer and the first or second thin film electrode.

[3] The image display medium according to [1], wherein the display layer includes a liquid crystal layer and a photoconductor layer.

[4] The above-mentioned [1], further comprising first and second extraction electrodes connected to the surfaces of the first and second thin film electrodes for electrical connection with the outside. ] The image display medium as described in.

[5] In the above [4], the second substrate has an extraction hole for enabling electrical connection between the second thin film electrode and the second extraction electrode. The image display medium described.

[ 6 ] The image display medium according to [1], further including an insulating member at an end of the first and / or second thin film electrode.

[ 7 ] The image display medium according to [1], further comprising a protective layer covering the entire surface.

  With the image display medium according to the first aspect of the present invention, the occurrence of a short circuit between the electrodes is effectively prevented, the reliability of the display portion is high, and a simple and inexpensive configuration is realized.

  With the image display medium according to claim 2 of the present invention, the above-described effects can be exhibited smoothly and reliably.

  The image display medium according to claim 3 of the present invention realizes an optical writing type “electronic paper” that exhibits the above-described effects.

  With the image display medium according to claim 4 of the present invention, the above-described effects can be exhibited smoothly and reliably.

  With the image display medium according to claim 5 of the present invention, the above-described effects can be exhibited smoothly and reliably.

Since the image display medium according to claim 1 of the present invention, having the structure of "the first and second thin film electrode is a full-surface electrode formed on the entire surface of the first and second substrates" In particular, the above-described effects are exhibited effectively.

With the image display media according to claims 6 to 7 of the present invention, the above-described effects can be exhibited more smoothly and reliably.

[First Embodiment]
(Configuration of image display medium)
1A and 1B show an image display medium according to a first embodiment of the present invention, where FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line AA.

  As shown in FIG. 1, an image display medium 10 according to the present embodiment includes a first substrate laminate 1 in which a first thin film electrode 1b is formed on a first substrate 1a, and a first substrate laminate. A second thin film electrode 2b that is smaller than the first thin film electrode 1b is formed on a second substrate 2a that is opposed to the first substrate 1a and that is smaller than the first substrate 1a. Configuration comprising substrate laminate 2 and display layer 3 sandwiched between first thin film electrode 1b of first substrate laminate 1 and second thin film electrode 2b of second substrate laminate 2 have. Here, “A is smaller in plane than B” means that A has a smaller area than B, and that the whole of A is in the outer shape of B, and the first and second thin film electrodes 1b. 2b is included in a plane while maintaining a predetermined horizontal distance D between 2b.

  Further, in the image display medium 10 of the present embodiment, the adhesive layer 4 is connected between the display layer 3 and the second thin film electrode 2b, and the surfaces of the first and second thin film electrodes 1b and 2b are connected. The first and second extraction electrodes 1c and 2c for electrical connection with the outside are further provided. The adhesive layer 4 may be disposed between the display layer 3 and the first thin film electrode 1b.

  Further, in the image display medium 10 of the present embodiment, the second substrate 2a has an extraction hole 2d for enabling electrical connection between the second thin film electrode 2b and the second extraction electrode 2c. have. Furthermore, as the first and second thin film electrodes 1b and 2b, full-surface electrodes formed on the entire surfaces of the first and second substrates 1a and 2a are used.

  The image display medium 10 in the present embodiment is used as an IC card or the like to which a display function using “electronic paper” such as an optical writing type, a toner display type, and an electrophoretic method is added. Hereinafter, each component will be specifically described.

(Substrate laminate)
The first and second substrate laminates 1 and 2 are disposed opposite to the first substrate laminate 1 in which the first thin film electrode 1b is formed on the first substrate 1a and the first substrate laminate 1. The second substrate laminate 2 in which the second thin film electrode 2b that is smaller in plan than the first thin film electrode 1b is formed on the second substrate 2a that is smaller in plan than the first substrate 1a. It consists of and. Here, as the degree of planarity of the second substrate laminate 2 smaller than that of the first substrate laminate 1, the first and second thin film electrodes can be effectively prevented from being short-circuited. There is no particular limitation as long as the horizontal distance D between 1b and 2b can be maintained. For example, as shown in Table 1, the minimum creepage distance described in JIS C6950 that defines the safety of information technology equipment is applied. Thus, it can be determined from the voltage V applied between the thin film electrodes 1b and 2b, the comparative tracking index (CTI) of the material constituting the display layer 3, and the degree of contamination. For example, if the CTI is 600 or less and the pollution degree is 2, which corresponds to a normal office environment, if V is 200V, D is 1.0 mm or more, if V is 400V, D is 2.0 mm or more, and V is 600V. For example, D can be determined to be 3.2 mm or more. Further, when the end portion of the thin film electrode is covered with an insulating member, the distance D can be made smaller than the above. For example, when V is 200 V, D is 0.4 mm, when D is 400 V, 1.0 mm, 600 V In this case, it can be determined as 1.8 mm.
The unit in Table 1 is mm.

  As the 1st and 2nd board | substrates 1a and 2a which comprise the 1st and 2nd board | substrate laminated bodies 1 and 2, at least one located in the display side is a polyethylene terephthalate (PET) whose thickness is 25-500 micrometers, for example. And the like that are made of a transparent resin material.

  As the first and second thin film electrodes 1b and 2b constituting the first and second substrate laminates 1 and 2, at least one of them positioned on the display side is, for example, indium tin oxide (ITO) of 10 to 200 nm. And a transparent electrode made of indium zinc oxide, zinc oxide or the like.

As described above, the first and second thin film electrodes 1b and 2b are both configured to have the form of full-surface electrodes .

(Display layer)
As the display layer 3, although it changes with kinds of the image display medium 10, what consists of a layer which has a liquid crystal, a colored particle, etc. can be mentioned, for example. In the case where the image display medium 10 is an optical writing type “electronic paper”, a liquid crystal layer and a photoconductor layer may be included. Specific examples of such a display layer 3 include, for example, a liquid crystal layer whose reflectance (transmittance) changes according to an applied voltage, a light absorption layer that absorbs light, and a resistance value that is reduced by light irradiation. Examples thereof include a structure in which a photoconductor layer is laminated in order from the display surface side, or a structure in which a light absorption layer, a photoconductor layer, an isolation layer, and a liquid crystal layer are laminated in order from the display surface side. Note that examples of the liquid crystal layer include a polymer dispersed liquid crystal and a microencapsulated liquid crystal (for example, a liquid crystal layer configured to have a microcapsule in which a cholesteric liquid crystal is sealed). Examples of the photoconductor layer may include a charge transport layer and a pair of charge generation layers stacked on both sides of the charge transport layer. Thus, an alternating voltage can be applied to the liquid crystal layer, so that deterioration of the liquid crystal layer can be suppressed, and the driving voltage can be lowered and the lifetime of the electronic paper can be increased. Further, as the display layer 3, in addition to the above, a microencapsulated electrophoretic element, a gyricon element, and the like can be given.

(Adhesive layer)
Although there is no restriction | limiting in particular as the adhesive bond layer 4, For example, an acrylic type and a urethane type adhesive agent or an adhesive can be mentioned. The thickness of the adhesive layer 4 is preferably 1 to 20 μm, for example. In the present embodiment, the case where the adhesive layer 4 is used will be described. However, without using the adhesive layer 4, for example, the display layer 3 and the second thin film electrode 2b are bonded together by pressure bonding or the like. May be.

(Extraction electrode)
The first and second extraction electrodes 1c and 2c are made of a metal such as Ni having a thickness of 25 to 200 μm, for example, and have higher rigidity or hardness than the first and second thin film electrodes 1b and 2b. It is preferable.

(Protective layer)
In the present embodiment, although not shown, it is preferable to further include a protective layer covering the whole. As such a protective layer, for example, a thermoplastic film made of a transparent thermoplastic resin using PET (polyethylene terephthalate), amorphous PET (PET-G), polyvinyl chloride, polyester, or a combination thereof. Can be mentioned. Such a thermoplastic film is formed, for example, by thermocompression bonding a thermoplastic member to the surface of the image display medium 10 using a bonding tool. In this case, it is preferable to have an extraction hole for connecting to the first and second extraction electrodes 1c and 2c from the outside. In order to prevent wear of the extraction hole, a metal pipe such as Ni or stainless steel is fitted into the extraction hole, and the first and second extraction electrodes 1c and 2c are wired in the metal pipe. It may be.

(IC chip)
In this embodiment mode, although not illustrated, an IC chip such as a wireless tag may be mounted in a predetermined area as necessary.

(Production of image display medium)
2-4 is explanatory drawing which shows the manufacturing process of the image display medium based on the 1st Embodiment of this invention in order of a process.

  2A and 2B show a first manufacturing process of the image marking medium according to the first embodiment of the present invention, where FIG. 2A is a plan view and FIG. 2B is a sectional view taken along the line BB in FIG. As shown in FIGS. 2A and 2B, the display layer 3 is disposed on the surface of the first substrate stack 1 in which the first thin film electrode 1b is formed on the first substrate 1a. A laminate S1 is prepared. Next, the first stacked body S1 is cut out along the first cutout line L1 by, for example, machining or laser processing to obtain a plurality of first cutout bodies K1 (two in FIG. 2A). Is shown by oblique lines).

  3A and 3B show a second manufacturing process of the image display medium according to the first embodiment of the present invention, in which FIG. 3A is a plan view and FIG. 3B is a sectional view taken along the line C-C. As shown in FIGS. 3A and 3B, the adhesive layer 4 is disposed on the surface of the second substrate laminate 2 in which the second thin film electrode 2b is formed on the second substrate 2a. A second stacked body S2 is prepared. Next, the second stacked body S2 is cut out along the second cutout line L2 by, for example, machining or laser processing, and a plurality of second cutouts smaller in plan than the first cutout body K1. A body K2 (in FIG. 3A, three cases are indicated by oblique lines) is produced. The second substrate 2b has an extraction hole 2d for enabling electrical connection between the second thin film electrode 2b and the above-described second extraction electrode 2c. It is formed by laser processing.

FIG. 4 shows a third manufacturing process of the image display medium according to the first embodiment of the present invention. FIG. 4A shows a state before the first cutout body K1 and the second cutout body K2 are bonded together. The state (b) is a cross-sectional view showing the state after the first cutout body K1 and the second cutout body K2 are bonded together. As shown in FIGS. 4A and 4B, the second cutout K produced in the second step is turned upside down on the surface of the first cutout K1 produced in the first step. The display layer 3 and the adhesive layer 4 face each other, and are heated and pressed as necessary to bond them together. In this case, for example, the first cutout body K1 and the second cutout body K2 fixed on the base are heated from the vertical direction with the cushioning material interposed therebetween (for example, 60 to 150 ° C.) using a bonding tool. , By applying pressure (for example, 0.1 to 1 N / mm ² ). In addition, for example, by using a laminating method using a heating roller, the first cutout body K1 and the second cutout body K2 may be heated and pressurized under the same conditions from the front and back surfaces.

  Next, first and second extraction electrodes 1c and 2c for electrical connection with the outside are connected to the surfaces of the first and second thin film electrodes 1b and 2b. Here, the second extraction electrode 2c is wired in the extraction hole 2d formed in the second substrate 2a. Next, if necessary, an IC chip (not shown) such as a wireless tag is mounted, and a protective layer (not shown) covering the whole is formed. In this way, since the horizontal distance D between the first and second thin film electrodes 1b and 2b can be set large, it is possible to obtain the image display medium 10 that is not easily short-circuited. Moreover, since the method of this embodiment does not require patterning, the image display medium 10 can be manufactured at low cost.

[Second Embodiment]
(Configuration of image display medium)
5A and 5B show an image display medium according to a second embodiment of the present invention, in which FIG. 5A is a plan view and FIG. 5B is a cross-sectional view taken along line EE.

  As shown in FIGS. 5A and 5B, the image display medium 10 according to the present embodiment has an insulating member 5 (in FIG. 5A) at the ends of the first and second thin film electrodes 1b and 2b. Is the same as in the case of the first embodiment, except that the structure is more difficult to short-circuit than in the case of the first embodiment. In this case, workability is good because only one surface needs to be sealed. In addition, the insulating member 5 is also coated on the first thin film electrode 1b at the end on the first extraction electrode 1c side, but without covering the first thin film electrode 1b, As in the opposite end, only the second thin film electrode 2b may be sealed. Although there is no restriction | limiting in particular as such an insulating member 5, For example, an epoxy-type sealing agent can be mentioned.

  The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the invention. For example, the shape, size, arrangement, and the like of the extraction hole 2d are not limited to those shown in the drawings in the above embodiments. For example, the shape of the extraction hole 2d may be a square or the like. Further, instead of forming the extraction hole 2d, the second extraction electrode 2c is formed on the exposed second thin film electrode 2a by removing one end of the second substrate 2b from the end surface by a predetermined width. You may connect. In addition, the constituent elements of the above-described embodiments may be arbitrarily combined within a scope that does not depart from the spirit of the invention.

  The image display medium of the present invention can be used as an RFID (RF tag) as an application such as “electronic paper” or “digital paper” that can maintain the visibility and portability and can electrically rewrite display contents. Cards (eg, commuter pass, examination ticket, membership card, ID card, point card, cash card, credit card, merchandise distribution tag, etc.) and information media (eg, books, Newspapers, advertisements, fax output paper, business documents, etc.) are used effectively in various industrial fields such as transportation, medical, financial, distribution, publishing, information transmission, electronic equipment manufacturing, etc. The

The image display medium which concerns on the 1st Embodiment of this invention is shown, (a) is a top view, (b) is an AA sectional view. The 1st manufacturing process of the image marking medium which concerns on the 1st Embodiment of this invention is shown, (a) is a top view, (b) is the BB sectional drawing. The 2nd manufacturing process of the image marking medium which concerns on the 1st Embodiment of this invention is shown, (a) is a top view, (b) is the CC sectional view taken on the line. The 3rd manufacturing process of the image display medium which concerns on the 1st Embodiment of this invention is shown, (a) is the state before bonding a 1st cut-out body and a 2nd cut-out body, (b) is It is sectional drawing which shows the state after bonding a 1st cut-out body and a 2nd cut-out body, respectively. The image display medium which concerns on the 2nd Embodiment of this invention is shown, (a) is a top view, (b) is EE sectional view taken on the line.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate laminated body 1a 1st board | substrate 1b 1st thin film electrode 1c 1st extraction electrode 2 2nd board | substrate laminated body 2a 2nd board | substrate 2b 2nd thin film electrode 2c 2nd extraction electrode 2d Hole 3 Display layer 4 Adhesive layer 5 Insulating member 10 Image display medium D Horizontal distance K1 First cutout body K2 Second cutout body L1 First cutout line L2 Second cutout line S1 First laminated body S2 First Laminate of 2

Claims (8)

A first substrate laminate in which a first thin film electrode is formed on a first substrate;
A second thin film electrode smaller than the first thin film electrode is formed on a second substrate smaller than the first substrate and opposed to the first substrate stack. A second substrate laminate,
A display layer sandwiched between a first thin film electrode of the first substrate laminate and a second thin film electrode of the second substrate laminate,
The first and second thin film electrodes are full surface electrodes formed on the entire surfaces of the first and second substrates,
The display layer is planarly smaller than the first thin film electrode and smaller than the second thin film electrode so that a horizontal distance can be maintained between the first thin film electrode and the second thin film electrode. The image display medium is also formed to be large in a plane.   The image display medium according to claim 1, further comprising an adhesive layer between the display layer and the first or second thin film electrode.   The image display medium according to claim 1, wherein the display layer includes a liquid crystal layer and a photoconductor layer.   The first and second extraction electrodes connected to the surfaces of the first and second thin film electrodes for electrical connection with the outside are further provided. Image display medium.   The image display according to claim 4, wherein the second substrate has an extraction hole for enabling electrical connection between the second thin film electrode and the second extraction electrode. Medium.   The image display medium according to claim 1, further comprising an insulating member at an end of the first and / or second thin film electrode.   The image display medium according to claim 1, further comprising a protective layer covering the whole.   The horizontal distance applies the minimum creepage distance described in JIS C6950, the voltage V applied between the first thin film electrode and the second thin film electrode, and the material constituting the display layer. The image display medium according to claim 1, wherein the image display medium is determined from a comparative tracking index (CTI) and a degree of contamination.

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