JP2016057573A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device having excellent visibility from contrast by a retroreflective structure and an electrophoretic medium in a day time to be a source of strong light such as sun light and capable of displaying a display having excellent visibility by retroreflecting light from a visual recognition side at night and capable of exerting a line of sight guidance effect through display switching by an electrophoretic medium.SOLUTION: A display device A includes: a pair of substrates 10, 11 opposing to each other with at least one of the substrates having light translucency; and electrodes 12, 12 for applying an electric field to an electrophoretic medium provided between the substrates 10, 11 of the pair of substrates, while an electrophoretic medium 20 including electrophoretic particles 25 and a retroreflective structure 30 are encapsulated between the pair of substrates 10, 11, and blocking light that reaches the retroreflective structure 30 freely by the electrophoretic medium 20.SELECTED DRAWING: Figure 1

Description

  The present invention provides a display having excellent visibility and a visual guidance effect by contrast between an electrophoretic display medium capable of reversibly changing a visual state by the action of an electric field or the like and a retroreflective structure. Relates to the device.

  Conventionally, various types of structures are known for display media that return reflected light in the direction irradiated with automobile light or the like, such as retroreflective signs. Although the brightness of these retroreflective structures is conspicuous, they do not have a line-of-sight guidance function that attracts people's attention by blinking or the like unlike LEDs and liquid crystal display devices.

  On the other hand, a self-luminous display medium such as a liquid crystal display device having an LED or a backlight has a problem that the visibility is significantly deteriorated by strong light such as sunlight.

On the other hand, as a display device in which a reflector such as retroreflection is added to a display medium such as liquid crystal or electrophoresis, for example,
1) a substrate, a circuit element provided on the substrate, an interlayer film provided on the circuit element and having an interlayer insulating layer and an interlayer connection provided in the interlayer insulating layer, and the interlayer film The electrode and the circuit element are electrically connected to each other via the interlayer connection portion, and the surface shape of the electrode on the interlayer film is substantially uniform. The electrode has a retroreflective property of reflecting light, and the reflective property of the electrode on the interlayer film is substantially uniform (see, for example, Patent Document 1),
2) A display substrate, a back substrate, a spacer that forms a gap between the display substrate and the back substrate, and two types of particles having different colors and charged polarities enclosed between the display substrate and the back substrate And a plurality of color filters that transmit light of a specific wavelength, and each of the two types of particles is a retroreflective particle and a black particle, for example (for example, Patent Document 2),
3) A pair of substrates, at least one of which is translucent and disposed opposite to each other, electrodes provided on surfaces of the pair of substrates facing each other, and dimming disposed between the pair of substrates. An electrochromic colored particle, a dispersion medium for dispersing the electrophoretic colored particle, and a reflective member having optical reflection characteristics different from that of the electrophoretic colored particle; And a difference between the contact angle (degree) of the electrophoretic colored particle surface with water and the contact angle (degree) of the reflection member surface with water is within a certain range (for example, Patent Document 3) is known.

However, the technique described in Patent Document 1 discloses a display device having a structure in which electrodes are electrically connected to circuit elements through an interlayer insulating layer in a display device such as an active matrix liquid crystal display device. The purpose is to improve the quality of the display device having excellent visibility in contrast between the electrophoretic display medium of the present invention and the retroreflective structure and the display device capable of exhibiting the line-of-sight effect. The object and technical idea of the invention (configuration and its operational effects, the same applies hereinafter) are different.
The technique described in Patent Document 2 is a display device that improves contrast by using retroreflective particles as electrophoretic particles, and is based on the contrast between the electrophoretic display medium of the present invention and a retroreflective structure. A display having excellent visibility and a display device capable of exhibiting a line-of-sight guidance effect are different in the object and technical idea of the invention.
The technique described in Patent Document 3 discloses the proximity technique of the present invention, but a white resin film in which granular reflecting members such as titanium oxide particles and many pores are disposed between electrodes. Reducing the affinity between the film-like reflective member and one or more types of electrophoretic colored particles, that is, the contact angle (degree) of water on the surface of the electrophoretic colored particles with the water on the surface of the reflective member By setting the difference in angle (degree) within a certain range, it is intended to prevent the adhesion of electrophoretic particles to the reflecting member and to obtain a display device with a small contrast decrease over time. The object of the present invention and the technical idea are different from the display having excellent visibility by contrast between the electrophoretic display medium of the present invention and the retroreflective structure and the display device capable of exhibiting the visual line guiding effect. .
As described above, in the conventional display device, the electrophoretic display medium and the retroreflective structure are skillfully combined, and the contrast due to the retroreflective property is excellent in the daytime and nighttime. At present, there is no display device capable of exhibiting a display having visibility and a gaze guidance effect.

JP 2003-255373 A (Claims, Examples, etc.) JP 2002-139750 A (Claims, Examples, etc.) JP 2008-58394 A [Patent No. 4033225 (Claims, Examples, etc.)]

  The present invention has been made in view of the above-described problems of the prior art and the current situation, and is intended to solve this problem. In the daytime when strong light such as sunlight is generated, the contrast between the retroreflective structure and the electrophoretic medium is used. With excellent visibility at night, the light from the viewing side is retroreflected at night to enable display with excellent visibility and display effect by switching the display with an electrophoretic medium. It is an object of the present invention to provide a display device that can be used.

  As a result of intensive studies to solve the above-described conventional problems and the like, the present inventor has at least one of a pair of substrates that are translucent and arranged to face each other, and the substrate between the pair of substrates. An electrode for applying an electric field to the electrophoretic medium, an electrophoretic medium including electrophoretic particles and a retroreflective structure are enclosed between the pair of substrates, and light reaching the retroreflective structure is electrically It has been found that a display device of the above-mentioned purpose can be obtained by making it possible to shut off with an electrophoretic medium, and the present invention has been completed.

That is, the present invention resides in the following (1) to (6).
(1) A pair of substrates, at least one of which is translucent and disposed opposite to each other, an electrode for applying an electric field to an electrophoretic medium provided between the pair of substrates, and the pair of substrates An electrophoretic medium including electrophoretic particles and a retroreflective structure are sealed between substrates, and light reaching the retroreflective structure can be blocked by the electrophoretic medium.
(2) The display device according to (1), wherein a partition wall is provided on one side or both sides of the pair of substrates.
(3) The display device according to (1) or (2), wherein the retroreflective structure is spherical.
(4) The display device according to (3), wherein the retroreflective structure has a size approximately equal to the distance between the substrates and does not move due to the flow of the electrophoretic medium.
(5) The display device according to (3), wherein the retroreflective structure is fixed to one of the substrates or the partition and does not move due to the flow of the electrophoretic medium.
(6) The display device according to any one of (1) to (5), wherein a reflective layer is provided on a back surface of the retroreflective structure.

  According to the present invention, there is excellent visibility in the contrast between the retroreflective structure and the electrophoretic medium in the daytime, which is the source of strong light such as sunlight, and the light from the viewer side in the nighttime. By providing retroreflection, it is possible to provide a display device that enables display with excellent visibility and can exhibit a line-of-sight inducing effect by display switching using an electrophoretic medium.

(A)-(c) shows an example of embodiment of the display apparatus of this invention, (a) is a schematic longitudinal cross-sectional view in case there is no application of an electric field, (b) and (c) are electric fields. It is each schematic longitudinal cross-sectional view which shows the operation state at the time of applying (+/-). It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. (A)-(c) shows an example of other embodiment of the display apparatus of this invention, (a) is a schematic longitudinal cross-sectional view in case there is no application of an electric field, (b) and (c) These are each schematic longitudinal cross-sectional views which show the operation state at the time of applying an electric field (±). It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. It is a schematic longitudinal cross-sectional view which shows other embodiment of the display apparatus of this invention. 6 is a schematic longitudinal sectional view showing a display device of Comparative Example 1. FIG. 10 is a schematic longitudinal sectional view showing a display device of Comparative Example 2. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic longitudinal sectional view showing an example of an embodiment of a display device of the present invention. (A) is a schematic longitudinal sectional view when no electric field is applied, and (b) and (c) are electric fields (± It is each schematic longitudinal cross-sectional view which shows the operation state at the time of applying ().
As shown in FIG. 1A, the display device A according to this embodiment includes a pair of substrates 10 and 11 that are translucent and arranged so as to face each other, and the pair of substrates 10 and 11. Electrodes 12 and 12 for applying an electric field to the electrophoretic medium 20 provided between the substrates, the electrophoretic medium 20 including the electrophoretic particles 25 between the pair of substrates 10 and 11, and a retroreflective structure 30. And the light that reaches the retroreflective structure 30 can be blocked by the electrophoretic medium 20.

In the pair of substrates 10 and 11, the substrate 10 on the viewing side (front side) has a light-transmitting property, and the pair of substrates 10 and 11 is provided with electrodes 12 and 12. ing.
The substrates 10 and 11 are, for example, transparent inorganic materials such as glass, quartz, sapphire, MgO, LiF, and CaF ₂ , organic polymer films such as fluororesin, polyester, polycarbonate, polyethylene, and polyethylene terephthalate (PET), or ceramics. Etc. can be used.

The electrodes 12 provided on the substrates 10 and 11 are made of, for example, a transparent conductive material such as tin oxide-indium oxide (ITO), ZnO, SnO ₂ , aluminum (Al), gold (Au), platinum (Pt), copper ( It can be formed using a metal such as Cu), silver (Ag), nickel (Ni), chromium (Cr). Further, conductive polymers such as PEDOT / PVS and PEDOT / PSS, and transparent conductive materials such as titanium oxide, zinc oxide, and tin oxide may be used. These materials can be formed by methods such as vapor deposition, ion plating, sputtering, and various coating techniques. The shape of each electrode 12 is not particularly limited, and can be appropriately selected according to the structure of the display device and the like. The electrode 12 may be provided in contact with the substrates 10 and 11 or a TFT element or the like may be provided on the substrates 10 and 11.

  In the present embodiment, when the substrate 10 having the electrode 12 is a front electrode substrate, the substrate 10 and the electrode 12 are visually recognized through the electrode substrate to display characters and the like formed on the electrophoretic display medium. Can be formed of a light-transmitting material. In the present embodiment, the front electrode substrate is made of an ITO / PET film. Further, the substrate 11 and the electrode 12 on the back side may be formed of a light-transmitting material as in the case of the front side electrode substrate.

On the substrate 11 having the electrode 12 on the back side (the substrate opposite to the viewing side), a reflective layer 13 made of an aluminum (Al) vapor deposition layer (thickness: 200 nm) is formed. The reflective layer 13 is for increasing the retroreflection of the retroreflective structure 30 described later, and is not particularly limited as long as it can reflect light reaching the display device. Metal materials such as silver, platinum, copper, chromium, tin, nickel, cobalt, white pigments such as titanium oxide that scatter light and return a part of it as reflected light, other colored pigments, etc. The reflective layer may be formed of a combined material or the like. Further, a colored material can be used to adjust the reflected light to an arbitrary color.
The thickness of the reflective layer 13 varies depending on the material used, the structure and material of the retroreflective structure, the size of the display device, and the like, but is about 1 nm to 1000 μm.

In the present embodiment, the electrophoretic medium 20 and the retroreflective structure 30 are enclosed between the pair of substrates 10 and 11. Hereinafter, the electrophoretic medium 20 and the retroreflective structure 30 enclosed between the substrates are referred to as “encapsulation layer”.
The encapsulating layer prevents the encapsulating layer from being biased in the horizontal direction by the partition 15 provided on one side or both sides of the pair of substrates 10 and 11, and the shape of the partition 15 is not limited. Further, the pair of substrates 10 and 11 can be integrated through the partition wall 15 by applying an adhesive on the partition wall 15 or by fusing the partition wall 15. By providing the partition wall 15, the time-dependent bias of the electrophoretic particles 25 and the retroreflective structure 30 can be suppressed.
In the present embodiment, the partition wall 15 is erected on the reflective layer 13 formed on the substrate 11. The partition wall 15 can be formed using a resin material such as a PET film. For example, a plurality of cells 16 can be formed by laser processing a synthetic resin such as a PET film having a certain thickness to form a square, hexagon, circle, or the like. It is also possible to form a cell made of a cross-shaped structure 15 by forming a thermoplastic resin on the reflective layer 13 and using a method such as hot embossing. Furthermore, after an insulating layer is formed over the electrode 12, a plurality of cells can be formed by patterning the insulating layer using a photolithography method.
A plurality of small chambers are formed by insulating partition walls 15, 15... Standing on the reflective layer 13 of the substrate 11. These small chambers (cells) are separated by the partition walls 15, and are circular and rectangular. It can be provided in various shapes such as (rectangular, square) and hexagonal. In addition, the partition 15 may be called a spacer, a pillar, a wall, a rib, etc. from the shape and the objective.

An electrophoretic medium 20 including electrophoretic particles 25 and a retroreflective structure 30 are enclosed in a cell 16 formed on the electrode substrate 11.
The electrophoretic medium 20 is configured by filling the cells 16 with electrophoretic ink containing electrophoretic particles 25.
The electrophoretic ink to be used is not particularly limited. For example, any electrophoretic ink may be used as long as it contains at least one type of electrophoretic particles 25 and a solvent such as a solvent. As the electrophoretic particles 25, for example, colored or colorless (white) inorganic pigment particles, organic pigment particles, polymer resin particles, and the like can be used, and these can be used alone (one type) or in combination of two or more types. Can be used. Further, the fine particles may be subjected to lipophilic or hydrophilic surface treatment.
As a specific example, it can be formed with positively charged white particles and a solvent (solvent) in which the particles are dispersed. As the white particles, white pigments such as titanium oxide, white resin particles, or resin particles colored in white can be used. Alternatively, only one type of charged particle such as black particles may be used. As the black particles, black pigments such as titanium black and carbon black, resin particles colored in black, and the like can be used. Moreover, a fluorescent pigment, a luminous pigment, etc. can be used individually or in combination. Furthermore, it is possible to arbitrarily use particles of various colors using two or more kinds of particles. In addition, as the solvent, for example, hydrocarbon-based, aromatic-based, ester-based, ketone-based, terpene-based, alcohol-based, silicone-based, fluorine-based, and water-based solvents are used alone or in combination of two or more. be able to.

The electrophoretic ink may further contain a dispersant and a charge control agent in addition to one or more types of electrophoretic particles and a solvent. Examples of the dispersant that can be used include various conventionally used dispersants, surfactants and polymer surfactants, such as nonionic surfactants, anionic surfactants, cationic surfactants, Examples include amphoteric surfactants and polymer surfactants, but are not limited thereto. As the charge control agent, various types used for electrophoretic display can be used. In addition to the dispersant and charge control agent, one or more additives for imparting necessary characteristics may be contained.
By combining the types of the components constituting the electrophoretic ink and the contents of the components, the electrophoretic medium 20 in which suitable electrophoretic particles 25 are dispersed can be prepared. The shape, size, charge amount, etc. of the electrophoretic particles 25 are not particularly limited, and light that reaches the retroreflective structure 30 is blocked as long as it is a particle that migrates with respect to an electric field. Therefore, the effect of the present invention can be obtained.

In addition, as the retroreflective structure 30 to be encapsulated, a generally retroreflective structure such as a glass bead, a prism, a corner cube, or a resin bead can be used. The structure is not particularly limited as long as it can be sealed between the substrates 10 and 11.
In this embodiment, the retroreflective structure 30 is composed of spherical glass beads (diameter 40 μm) from the viewpoint that the display device configuration can be simplified and the retroreflective performance can be increased by a high refractive index. The size is fixed so that it cannot move geometrically, that is, the retroreflective structure 30 has a size comparable to the distance t between the substrates (in this embodiment, 40 μm). It is fixed so that it does not move due to the flow of 20.
Further, the retroreflective structure 30 to be used can be fixed by being integrated with one of the substrates 10 and 11 and the partition wall 15 or the like. It may be prevented from moving due to the flow of the electrophoresis medium 20.

The number of the retroreflective structures 30 to be encapsulated, the arrangement structure, etc. are recursive in terms of retroreflectivity, and light that reaches the retroreflective structures can be blocked by the electrophoretic medium. The narrowest state in which the retroreflective structures 30 that are spheres are closely packed, such as the spacing between the reflective structures 30 and between the retroreflective structures 30 and the partition walls 15 so as to move to the respective electrodes 12 side, etc. However, since the space through which the electrophoretic particles can pass is secured, the number of arrangement and the arrangement structure are not particularly limited. Moreover, since the top part of the retroreflective structure 30 is in point contact with the electrode 12, it does not have a retroreflective function unless light perpendicular to the substrate 10 acts on the part. Even if light perpendicular to 10 acts, the amount of light that reaches the retroreflective structure 30 and retroreflects is very small, and does not hinder light blocking by the electrophoretic medium.
The “retroreflection” defined in the present invention means that the retroreflectance is 10% or more, preferably 50% or more of the incident light retroreflected in a direction within ± 30 degrees from the incident direction. In each of the above embodiments, spherical glass beads are used as the retroreflective structure. However, the present invention is not limited to this, and a thermoplastic or thermosetting resin may be used as the material.

  In the present embodiment, the electrophoretic medium 20 and the retroreflective structure 30 are filled in the cells 16, and then a seal portion (not shown) provided on the outer peripheral edge of the electrode substrate 11 and each of the cells 16 are formed by a conventional method or the like. The display device A in which the electrophoretic medium 20 including the electrophoretic particles 25 and the retroreflective structure 30 are enclosed between the pair of substrates 10 and 11 is obtained by bonding the front electrode substrate 10 to the upper surface of the partition wall 15. In addition, if a control unit or the like is further provided, it can be used.

In the display device A of the present embodiment configured as described above, when an electric field (±) is applied to each electrode 12 of the substrates 10 and 11, for example, when the substrate 10 side is a cathode and the substrate 11 side is an anode. As shown in FIG. 1B, the electrophoretic particles 25 and the retroreflective structure 30 included in the electrophoretic medium 20 have optically different properties as described above, and are thus retroreflective. The light reaching the conductive structure 30 can be blocked by the electrophoretic particles 25 of the electrophoretic medium 20, and the display device A performs display based on the optical characteristics of the particles 25 of the electrophoretic medium. On the other hand, when not blocking, that is, when the substrate 10 side is an anode and the substrate 11 side is a cathode, the optical characteristics of the retroreflective structure 30 (incident are incident) as shown in FIG. The light is retroreflected). Furthermore, when the display device A is used for a road sign (signs) or the like, excellent visibility is exhibited by retroreflection to a car light or the like at night. Further, if the blocking and non-blocking by the electrophoretic medium 20 are repeated, the blinking operation is performed, and the display of the electrophoretic medium 20 and the retroreflective structure 30 is repeated, so that the visual line guiding effect can be exhibited. .
Therefore, according to the display device A of the present embodiment, the daytime that is the source of strong light such as sunlight has excellent visibility due to the contrast between the retroreflective structure 30 and the electrophoretic medium 20, and at night. And the like recursively reflect light from the viewing side, thereby enabling a display having excellent visibility and a display device capable of exhibiting a line-of-sight inducing effect by display switching (flashing) by the electrophoretic medium 20. (Hereinafter referred to as “function similar to display device A”), and suitable for applications such as signs, outdoor signs, outdoor posters, traffic information signs, road construction signs, road construction signals, emergency exit signs, etc. Can be used.

2-8 is a schematic sectional drawing of each display apparatus BH used as other embodiment of this invention. In the drawings of FIGS. 2 to 10 and Comparative Examples 1 and 2, the same components as those in the embodiment of FIG.
As shown in FIG. 2, the display device B according to the second embodiment of the present invention has Al (thickness) in which aluminum is vapor-deposited on the surface of a resin film (thickness: 5 μm) whose reflective layer is made of a conductive adhesive. 200 nm) The point made of the vapor-deposited resin layer 14, the partition wall 15 standing on the electrode 12 on the substrate 10 side, and the lower surface of the retroreflective structure 30 made of glass beads on the resin layer of the Al vapor-deposited resin layer 14 1 is different from the display device A of FIG. 1 in that it is integrated.
According to this display device B, it can function in the same manner as the display device A in FIG. 1 and the resin layer of the resin layer 14 with Al vapor deposition is made of a conductive adhesive, so that the resistance value is In order to function as an electrode at a low level, the Al-deposited resin layer 14 serves as the electrode 12 on the substrate 11 side.

  As shown in FIG. 3, the display device C according to the third embodiment of the present invention forms a reflective layer on the surface of the retroreflective structure 30 made of glass beads, specifically, one side of the retroreflective structure 30. 1 is different from the display device A in FIG. 1 and can function in the same manner as the display device A in that an Al vapor deposition layer 31 is provided on the surface to form a reflective layer and the reflective layer 13 is omitted.

  As shown in FIG. 4, the display device D according to the fourth embodiment of the present invention includes a retroreflective structure 30 made of glass beads composed of transparent colored particles 32 made of colored glass beads. The display device A is different from the display device A and can function in the same manner as the display device A. The transparent colored particles 32 give the optical properties of the retroreflective structure a property other than white. .

  As shown in FIG. 5, the display device E according to the fifth embodiment of the present invention is such that the reflective layer 13 also serves as an electrode, that is, the reflective layer 13 has conductivity and gloss such as Al deposition, Further, it is different from the display device A of FIG. 1 in that the electrode 12 on the substrate 11 side is omitted, and can function in the same manner as the display device A.

As shown in FIGS. 6A to 6C, the display device F according to the sixth embodiment of the present invention includes a retroreflective structure made of the glass beads of FIG. 1 and a prism having retroreflective properties. The display device A is different from the display device A in FIG. 1 in that the retroreflective structure 33 is used. This prism is made of various inorganic materials, organic polymers, ceramics, and the like. In this embodiment, the prism is made of an organic polymer. In order to apply an electric field between the electrodes, a part of the prism has a substrate 11 side. The electrode 12 is provided on the electrode 12 in a state having a hole for being exposed to the encapsulating layer.
When the retroreflective structure 33 made of this prism is used, an electrode, for example, an electrode made of ITO is formed on the prism by sputtering, so that the electrophoretic medium 20 flows between the substrates. It is also possible to apply an electric field of Also, conductivity can be imparted to the prism itself. In this case, the electrode 12 on the substrate 11 side and the hole for exposing the electrode 12 on the substrate 11 side to the encapsulating layer can be omitted.
In the display device F, as shown in FIG. 6B, the light reaching the retroreflective structure 33 made of a prism can be blocked by the electrophoretic medium 20, and the display device has particles of the electrophoretic medium. The display is made with 25 optical characteristics. On the other hand, when not blocked, retroreflective display is performed by the optical characteristics of the retroreflective structure 33 as shown in FIG. 6C, and the display device A can function in the same manner.

As shown in FIG. 7, the display device G according to the seventh embodiment of the present invention includes an electrophoretic medium 20 and a retroreflective structure 30 made of glass beads between the substrates without providing the partition wall 15. This is different from the display device A of FIG.
This display device G can be used in a situation where the electrophoretic particles 25 are sunk due to gravity or vibration when placed vertically, for example, signs placed on a horizontal surface on a floor, etc. It can function similarly to the device A.

As shown in FIG. 8, the display device H according to the eighth embodiment of the present invention is different from the display device A of FIG. 1 in that the retroreflective structure 30 made of glass beads is not fixed.
The display device H can be used for signs placed on a horizontal surface on a floor or the like, for example, when the retroreflective structure 30 made of glass beads sinks due to gravity or vibration when placed vertically, for example, It can function in the same manner as the display device A.

The present invention is configured as described above, but is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea of the present invention.
For example, in the above embodiment, the retroreflective property of the retroreflective structure 30 may be effective not only for visible light but also for light in the infrared region and ultraviolet region. In that case, it is possible to use the visual guidance effect by blinking as a signal to the device by retroreflecting the device having sensitivity to infrared light or ultraviolet light.
Further, by controlling the retroreflection of visible light and infrared light, it may be used as an apparatus for adjusting radiant heat due to sunlight or the like to the irradiated object.
Furthermore, the display device can reduce the contrast between the electrophoretic medium and the retroreflective structure, and can obtain the contrast between the electrophoretic medium and the retroreflective structure only when irradiated with strong light such as a headlight of an automobile at night. It may be used as
Furthermore, the retroreflective control is applied to control the function of an irradiated object such as a screen that projects an image by a projector, and can be used as a device for controlling the projected / non-projected state of an image by the projector on the irradiated object side. It can be used in combination with a technique such as projection mapping.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further, this invention is not limited to the following Example.

(Example 1, conforming to FIG. 1)
Formation of electrode substrates (indicated by reference numerals 10 and 12 and indicated by reference numerals 11 and 12) and a reflective layer 13 As a pair of electrode substrates, an ITO film, which is a transparent material, is formed so as to have a surface resistance of about 500 Ω / □. A PET sheet (10 × 10 cm) was used (hereinafter referred to as “ITO-PET”).
An Al vapor deposition layer having a thickness of 200 nm was formed on one back-side electrode substrate by vacuum vapor deposition.
A photosensitive resin sheet made of an acrylic resin is bonded onto the Al vapor deposition layer, exposed to UV, and developed with an organic solvent to form a plurality of lattice-like cells (height 40 μm, cell size) made of insulating partition walls. A 300 μm hexagon and an aperture ratio of 87% were formed in the range of 8 × 10 cm of the ITO-PET.

Composition of electrophoretic medium used:
Solvent: normal dodecane: 75 mass%, titanium oxide particles: 20 mass%, nonionic surfactant: 5 mass% (total 100 mass%).
As the retroreflective structure, spherical glass beads having a diameter of 40 μm were used. Inter-substrate distance T: 40 μm
The cell was filled with the retroreflective structure 30 and the electrophoretic medium 20.
After filling, a UV curable resin was dropped onto the outer peripheral part (display area) of the cell using a dispenser to form a seal part (height 0.5 mm, width 5 mm). Subsequently, the front side electrode substrate [ITO-PET, 500RK (manufactured by Toyobo Co., Ltd.)] was bonded to produce a display device A.

(Example 2, conforming to FIG. 1)
A display device was produced in the same manner as in Example 1 except that the reflective layer 13 was not formed in Example 1. In Example 2, since the 200 nm aluminum vapor deposition layer is eliminated, the retroreflective structure 30 sandwiched between the opposed substrates is not fixed.

(Example 3, according to FIG. 6)
In Example 1 above, a retroreflective prism sheet 3310FP (manufactured by Sumitomo 3M Co., Ltd.) having holes of about 100 μm at 300 μm intervals was bonded onto ITO-PET, and the photosensitive resin made of acrylic resin was formed thereon. A display device was produced in the same manner as in Example 1 except that the resin sheet was bonded.

(Example 4, conforming to FIG. 7)
A display device was manufactured in the same manner as in Example 1 except that the partition wall 15 was not formed in Example 1.

(Example 5, according to FIG. 8)
A display device was produced in the same manner as in Example 1 except that the retroreflective structure (glass beads) was not fixed.

(Comparative Example 1, FIG. 9 compliant)
A display device was produced in the same manner as in Example 1 except that the retroreflective structure (glass beads) was replaced with opaque colored particles 40 (diameter 40 μm) having no retroreflective property in Example 1.

(Comparative example 2, conforming to FIG. 10)
In Example 1 above, a display device was produced in the same manner as in Example 1 except that the following coating composition 45 was filled instead of the electrophoresis medium.
Coating composition:
Solvent: Propylene glycol monomethyl ether: 60% by mass, carbon black: 15% by mass, polymer surfactant: 25% by mass (total 100% by mass).

(Performance evaluation of display devices of Examples 1 to 5 and Comparative Examples 1 and 2)
By using the display devices obtained in Examples 1 to 5 and Comparative Examples 1 and 2 above, daytime visibility, nighttime visibility, daytime gaze guidance effect, night gaze guidance effect, and aptitude use aptitude by the following methods ,evaluated.
These results are shown in Table 1 below.

(Evaluation method for daytime visibility and daytime gaze guidance effect)
Daytime visibility was evaluated by the following evaluation criteria by installing a display device beside a specific outdoor passage, examining how many of the 10 passers-by who did not inform the test contents, and noticed the presence of the display device.
The daytime gaze guidance effect was evaluated by blinking the display device in the same manner as daytime visibility.
Evaluation criteria for daytime visibility and daytime gaze guidance effects:
A: 9-10 people noticed.
○: 6-8 people noticed.
Δ: 3 to 5 people noticed
X: 0-2 people noticed.

(Evaluation method of night visibility and night gaze guidance effect)
Night visibility and night gaze guidance effect were evaluated in the same way by daytime visibility and day gaze guidance effect evaluation methods / evaluation criteria, except that the light was given to passers-by and that the night visibility was conducted at night.

(Evaluation method for aptitude use aptitude)
Appropriate for standing use is the same method as daytime visibility, etc., after using it for 1 month by standing, daytime visibility, daytime gaze guidance effect, nighttime visibility, nighttime gaze guidance effect (the above four items) Was evaluated based on the following evaluation criteria.
Evaluation criteria for aptitude suitability:
Adaptation for leaning: Three or more of the four items maintain the evaluation criteria.
Horizontal level recommendation: Two or more of the four items have dropped the evaluation criteria.

  As is clear from the results in Table 1 above, each of the display devices of Examples 1 to 5 within the scope of the present invention is daytime visibility and nighttime compared to the display devices of Comparative Examples 1 and 2 that are outside the scope of the present invention. In addition to being excellent in visibility, daytime gaze guidance effect, and nighttime gaze guidance effect, it has been found that, particularly in the recommended use environment, it has excellent display performance and stability over time.

10, 11 Substrate 12 Electrode 15 Bulkhead 20 Electrophoretic medium 25 Electrophoretic particle 30 Retroreflective structure

  The display device of the present invention can be suitably used for applications such as signs, outdoor signs, outdoor posters, traffic information signs, road construction signs, road construction signals, emergency exit signs, and the like.

Claims (6)

  At least one of the pair of substrates having translucency and opposingly disposed, an electrode for applying an electric field to an electrophoretic medium provided between the pair of substrates, and the pair of substrates An electrophoretic medium including electrophoretic particles and a retroreflective structure are enclosed, and light reaching the retroreflective structure can be blocked by the electrophoretic medium.   The display device according to claim 1, wherein a partition wall is provided on one side or both sides of the pair of substrates.   The display device according to claim 1, wherein the retroreflective structure is spherical.   4. The display device according to claim 3, wherein the retroreflective structure has a size approximately equal to the distance between the substrates and does not move due to the flow of the electrophoretic medium.   The display device according to claim 3, wherein the retroreflective structure is fixed to one of the substrates or the partition wall and does not move due to the flow of the electrophoretic medium.   The display device according to claim 3, wherein a reflective layer is provided on a back surface of the retroreflective structure.

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