JPH05108017A - Visible display device - Google Patents

Abstract

PURPOSE:To stabilize visual display by using liquid paraffin as an oil to be contained with magnetic flakes in microcapsules. CONSTITUTION:This device has a transparent base body 20, microcapsule layer 30 to form the visual display area, and a magnetic sheet 40 which forms a magnetic field to hold a magnetic recording area and to make visual display. The microcapsule layer 30 consists of microcapsules 32 dispersed in a binder 31, and the microcapsule 32 contains magnetic flakes 32 and liquid paraffin 33 which functions as an oily liquid. Namely, the liquid paraffin has proper viscosity at room temp. and stably holds magnetic flakes 34 in a desired oriented state in the microcapsule. Therefore, the visual display can be stabilized. Moreover, by disposing a proper surfactant, the magnetic flakes 34 can be more stably contained.

Description

Detailed Description of the Invention

[0001]

[Object of the Invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual display device,
In particular, a plurality of microcapsules, which contain magnetic flakes whose orientation direction can be changed according to the magnetic field together with oil and whose reflection direction of visible incident light can be changed depending on the orientation direction, are arranged on the surface of the transparent substrate. The present invention relates to a visible display device which becomes a visible display region by forming a microcapsule layer by dispersing it in the binder.

[0003]

2. Description of the Related Art Conventionally, as this type of visual display device,
A microcapsule layer is formed by attaching microcapsules containing oil and magnetic flakes to the surface of a transparent substrate with a transparent binder, and visible when the magnetic flakes are oriented parallel to the surface of the transparent substrate. Reflects incident light to visually display the bright color of magnetic flakes, and when the magnetic flakes are oriented perpendicular to the surface of the transparent substrate, does not reflect visible incident light and has a dark color of the magnetic sheet.
It has been proposed that a visible display (for example, black) is achieved and a visible display is achieved by the contrast between them.

[0004]

[Problems to be solved] However, in the conventional visual display device, the oil contained in the microcapsules together with the magnetic flakes was formed by a low molecular weight organic solvent (for example, dodecylbenzene). There is a drawback that the viscosity is as small as 0.3 to 15 cP at 20 ° C, and therefore (ii) there is a drawback that the magnetic flakes cannot be stably held in a predetermined orientation direction, and (iii) a visible display due to vibration or other disturbances. There was a drawback that it became unclear.

Therefore, in order to eliminate this drawback, the present invention forms the oil contained with the magnetic flakes in the microcapsules in the microcapsule layer formed as the visible display region on the transparent substrate by using liquid paraffin. The present invention is intended to provide a visible display device.

[0006]

[Constitution of the invention]

[0007]

[Means for Solving the Problems] The means for solving the problems provided by the present invention is that "a magnetic flake whose orientation direction is changed in response to a magnetic field is housed together with oil to reflect visible incident light depending on the orientation direction. In a visible display device in which a plurality of microcapsules whose directions are changed are dispersed in a binder arranged on the surface of a transparent base material to form a microcapsule layer as a visible display area, oil is liquid paraffin (33). It is a visible display device characterized by being formed by.

[0008]

In the visual display device according to the present invention, as clearly described in the above [Means for Solving Problems], the magnetic flakes whose orientation direction can be changed according to the magnetic field are accommodated together with the oil, and depending on the orientation direction. A visible display device in which a plurality of microcapsules in which the reflection direction of visible incident light is changed is dispersed in a binder arranged on the surface of a transparent substrate to form a microcapsule layer as a visible display region, In particular, since the oil is formed by liquid paraffin, (i) it has a function of stably orienting the magnetic flakes, and (ii) it has a function of stabilizing the visible display, and consequently (iii) the visible display. It has the effect of clarifying.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a visual display device according to the present invention will be specifically described with reference to the accompanying drawings and preferred embodiments.

However, the embodiment described below
It is described to facilitate or facilitate understanding of the present invention, and not to limit the present invention.

In other words, each element disclosed in the embodiments described below includes all design changes and equivalent replacements within the spirit and technical scope of the present invention.

(Description of the accompanying drawings)

FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a visible display device according to the present invention, and in particular, a microcapsule layer 30 which functions as a visible display region on one surface of a transparent substrate 20. Is arranged and the microcapsule layer
It shows a state in which the magnetic sheet 40 is arranged on the surface of 30 so as to form a magnetic field for visible display.

FIG. 2 is a partially enlarged sectional view showing an enlarged part of the embodiment shown in FIG. 1, particularly when the magnetization direction of the magnetic sheet 40 is parallel to the surface. 3 shows the correlation between the magnetization direction of the magnetic sheet 40 and the orientation direction of the magnetic flakes 34 contained in the microcapsules 32 in the microcapsule layer 30 .

FIG. 3 is a partially enlarged cross-sectional view showing a part of the embodiment shown in FIG. 1 in an enlarged manner. In particular, when the magnetization direction of the magnetic sheet 40 is perpendicular to the surface. 3 shows the correlation between the magnetization direction of the magnetic sheet 40 and the orientation direction of the magnetic flakes 34 contained in the microcapsules 32 in the microcapsule layer 30 .

FIGS. 4A and 4B are flowcharts showing an example of the manufacturing procedure of the embodiment shown in FIG.

(Structure of Example)

First, with reference to FIGS. 1 to 3, the structure of an embodiment of a visual display device according to the present invention will be described in detail.

A visible display device 10 according to the present invention includes a transparent base material 20 , a microcapsule layer 30 arranged to form a visible display region on at least one surface of the transparent base material 20 , A magnetic sheet 40 which is arranged on the surface of the microcapsule layer 30 so as to form a magnetic field for visible display according to the recorded content of the magnetic recording area (that is, the magnetization state), I have a package.

The transparent base material 20 is a transparent material having an appropriate thickness.
(For example, polyethylene terephthalate film)
And is functioning as a holder for the microcapsule layer 30 .

The microcapsule layer 30 is housed together with a plurality of microcapsules 32 dispersed in a binder 31 and magnetic flakes 34 in each microcapsule 32 and functions as an appropriate oily liquid (ie, "oil"). The liquid paraffin 33 is included. Binder 31
As will be apparent from the description below, is capable of transmitting the visible incident light L and the visible reflected lights L ^* and L ^** , and is particularly preferably transparent. The liquid paraffin 33 has a viscosity of about 200 cP at 20 ° C., and can stably hold the magnetic flakes 34 in the microcapsules 32 in a desired orientation state.

The size of the microcapsule 32 is 30 μm to 100 μm so that the visible incident light L is sufficiently reflected and can be clearly displayed when the recorded content of the magnetic recording area included in the magnetic sheet 40 is visibly displayed. It is preferable that the degree is set.

As the magnetic flakes 34, magnetic metal powder containing iron or nickel is adopted. The magnetic flakes 34 may contain magnetic metals such as silicon, molybdenum, aluminum, chromium and cobalt in addition to iron or nickel. Magnetic flakes
34 is preferably iron, nickel, iron nickel alloy, iron nickel chrome alloy, cobalt, cobalt aluminum alloy, samarium cobalt alloy, or the like. Here, if the magnetic flakes 34 are formed of magnetic metal powder containing nickel, the magnetic metal powder containing nickel exhibits white luster, and the color of the magnetic flakes 34 can be made a bright color, and It is possible to improve the contrast of the visible display area due to the difference in the orientation direction and to make the visible display clear.

The magnetic flakes 34 are required to appropriately reflect the visible incident light L, and the visible reflected light L emitted to the outside of the transparent substrate 20 when the orientation direction is parallel to the surface.
Since it is necessary to remarkably increase the light amount of ^* , it is preferable that it is plate-shaped. The size of the magnetic flakes 34 needs to be appropriately determined according to the size of the microcapsules 32, but if the major axis is 5 to 30 μm, the minor axis is 1 to 10 μm, and the thickness is 0.1 to 1 μm. , Usually preferred.

The magnetic flakes 34 are surrounded by magnetic flakes.
(I) Magnetic flakes 34 will agglomerate with each other if a suitable surfactant that does not easily react with 34 and liquid paraffin 33 (for example, Span 80 (Sorbitan monooleate from Atlas Spauder) or oleic acid) is placed. And (ii) the magnetic flakes 34 can be prevented from adhering to the wall surface of the microcapsules 32, so that the magnetic flakes 34 can be stably accommodated in the microcapsules 32, and thus the orientation direction of the magnetic flakes 34 is different. It is possible to improve the contrast of the visible display area due to.

The magnetic sheet 40 is made in a known manner by disposing a magnetic film (referred to as "magnetic layer") 41 on the surface of an appropriate base material 42 such as a plastic film,
The magnetic recording area is provided in the vicinity of the microcapsule layer 30 . The color of the magnetic sheet 40 (that is, the magnetic layer
41 or the color of the base material 42) is, for example, black so as to ensure the contrast of the visible display. Incidentally, the magnetic sheet 40 may be replaced with an appropriate magnetic field generating means as long as it can form a magnetic field in the visible display region, but here, for convenience of description, only this case will be described. Therefore, in the visible display device 10 according to the present invention, the magnetic sheet is used as the magnetic field generating means for forming a magnetic field in the visible display region.
It is not limited to only 40 .

(Manufacturing Procedure)

Further, with reference to FIGS. 1 to 4B, in order to deepen the understanding of an embodiment of the visual display device according to the present invention, an example of the manufacturing procedure thereof will be specifically described.

Dispersion of magnetic flakes 34

A magnetic metal powder (that is, "magnetic flakes 3") of an appropriate shape (for example, plate shape) prepared by a well-known method.
4 ”) is dispersed in liquid paraffin 33 with an appropriate surfactant (eg, oleic acid) (the resulting product is referred to as“ magnetic flake dispersion ”) and then stored in a stirrer (eg, ultrasonic stirrer). By doing so, it is stirred for a sufficient time.

Creation of microcapsules 32

By mixing water, gelatin, gum arabic and the like in appropriate proportions and stirring them sufficiently, a gelatin-rubber mixture which will be the binder 31 of the microcapsule layer 30 is prepared. Gelatin gum mixture is, for example, 650cc of water
And 10 g of gelatin (isoelectric point pH 4.5) and 10 g of gum arabic
It may be prepared by mixing and with each other and sufficiently stirring. Hereinafter, this case will be exemplified, but the present invention is not limited to this, and a desired material may be used in a desired ratio as long as the microcapsule layer 30 can be formed.

The gelatin rubber mixed solution is heated to an appropriate temperature while continuing the stirring for facilitating the reaction after the stirring is appropriately progressed.

The magnetic flake dispersion is added little by little to the gelatin rubber mixture under agitation and mixed, and the particles of the magnetic flake dispersion are dispersed by further stirring for a suitable time (resultant). “Intermediate dispersion”
That).

An aqueous acetic acid solution (for example, 10% by weight) is added dropwise to the intermediate dispersion liquid while continuing stirring until the pH becomes 4. This forms a coacervate film of gelatin and gum arabic around the fine particles of the magnetic flake dispersion (substantially liquid paraffin).

The dropwise addition of the aqueous acetic acid solution coagulates the coacervate film of gelatin and gum arabic placed around the fine particles of the magnetic flake dispersion (substantially liquid paraffin). For the purpose, it is allowed to cool to a moderate temperature with stirring.

The cooled intermediate dispersion contains gelatin and gum arabic which are bound around the deprotonated amino groups in the gelatin and formed around the fine particles of the magnetic flake dispersion (substantially liquid paraffin). Formaldehyde is added in an appropriate amount for the purpose of further solidifying the coacervate film. As a result, the microcapsules 32 are dispersed in gelatin and gum arabic (this is referred to as "microcapsule liquid"). The microcapsules 32 contain the magnetic flake dispersion liquid (and thus the magnetic flakes 34 and the liquid paraffin 33).

An aqueous sodium carbonate solution (for example, 20% by weight) is added to the microcapsule solution for the purpose of promoting desorption of protons from the amino groups of gelatin while continuing stirring.
It is added dropwise until the pH reaches 9.5.

The microcapsule solution should have a sufficient time.
After stirring for (for example, 3 to 30 hours), the microcapsules 34 are left to stand for a suitable time (for example, 24 hours) in order to make the microcapsules 34 float (hereinafter referred to as “floating capsules”).

Removal of empty capsules

The floating capsules in the microcapsule liquid are
It is taken out by an appropriate means. Pure water is added to the removed floating capsules (the resulting product is called "floating capsule liquid").

The floating capsule liquid is stirred for a sufficient time and then placed in a magnetic field of appropriate strength to remove the microcapsules containing no magnetic flakes 34 (referred to as "empty capsules").

In the floating capsule liquid, whether or not the remaining amount of empty capsules has become equal to or less than a predetermined value is determined in the remaining amount determination process of empty capsules.

The floating capsule liquid is repeatedly processed by the pure water addition step or the empty capsule residual quantity determination step until the empty capsule residual quantity falls below a predetermined value, and the empty capsules are removed.

Arrangement on transparent substrate 20

The floating capsule liquid is adjusted to an appropriate concentration (for example, the content concentration of microcapsules is 50% by weight) when the residual amount of empty capsules is below a predetermined value, and then a separately prepared transparent substrate ( For example, a microcapsule layer 30 is formed by coating one surface of a polyethylene terephthalate film) 20 with an appropriate thickness (for example, 100 μm to 200 μm) and drying and solidifying.

Arrangement of magnetic sheet 40

On the surface of the microcapsule layer 30 provided on the transparent base material 20 , a magnetic layer is formed on one surface of a base material (eg, polyethylene terephthalate film) 42 which is separately prepared.
By arranging the magnetic sheet 40 on which 41 is arranged in an appropriate manner, the visible display device 10 according to the present invention is obtained.

(Operation of Example)

Next, with reference to FIGS. 1 to 3, the operation of one embodiment of the visual display device according to the present invention will be described in detail.

When the magnetization direction in the magnetic recording area of the magnetic sheet 40 is changed from the direction parallel to the surface (see FIG. 2) to the direction perpendicular to the surface (see FIG. 3), the surface of the magnetic sheet 40 (that is, the magnetic layer). magnetic flakes 34 housed in microcapsules 32 in the microcapsule layer 30 which has been brought oriented in a direction parallel to the surface) of 41, the magnetic sheet 40
The orientation direction is changed in a direction orthogonal to the surface of the transparent layer 20 (that is, the surface of the magnetic layer 41), and the visible incident light L incident through the transparent substrate 20 is hardly reflected to the outside of the transparent substrate 20. .. Therefore, the visible incident light L, the surface of the magnetic layer 41 constituting the magnetic sheet 40 through the substrate 42 constituting the magnetic sheet 40 (i.e. facing surface on the surface of the microcapsule layer 30 (hereinafter (Referred to as “one surface”)), the transparent base material 20 ^becomes visible reflected light L ^**.
Will be emitted to the outside. Therefore, at this time, the color of one surface of the magnetic layer 41 is visually displayed in the visible display area. By the way, on one surface of the magnetic layer 41, a relatively large amount of visible incident light L is absorbed, and the amount of visible reflected light L ^** emitted to the outside of the transparent substrate 20 is small. When the color of the one surface of the magnetic layer 41 is black, the absorption amount of the visible input light L increases, and the visible reflected light L ^** is substantially not emitted to the outside of the transparent substrate 20 .

On the other hand, when the magnetization direction in the magnetic recording area of the magnetic sheet 40 is changed from the direction perpendicular to the surface (see FIG. 3) to the original parallel direction (see FIG. 2), the microcapsule layer is formed. The magnetic flakes 34 accommodated in the microcapsules 32 in 30 have the orientation direction changed in a direction parallel to the surface of the magnetic sheet 40 , and thus the transparent base material.
The visible incident light L incident via 20 is sufficiently reflected toward the outside of the transparent substrate 20 . Therefore, at this time, the color of the magnetic flakes 34 is visually displayed in the visible display area.

In short, the visual display device 10 according to the present invention
According to the microcapsules 32 of the microcapsule layer 30
Since the magnetic flakes 34 are housed together with the liquid paraffin 33 having a large viscosity, the magnetic flakes 34 can be stably held in a predetermined orientation direction, and thus the recording content recorded in the magnetic recording area of the magnetic sheet 40 can be improved. The visible display can be stabilized, and as a result, the recorded contents recorded in the magnetic recording area of the magnetic sheet 40 can be clearly displayed visually.

(Specific example)

In addition, in order to facilitate the understanding of the visual display device according to the present invention, it will be described more specifically with reference to numerical values and the like.

Example

10 g of plate-shaped magnetic metal powder having a nickel content of 100% by weight (that is, plate-shaped nickel powder)
Was dispersed in 150 cc of liquid paraffin as an oil together with 2 g of oleic acid as a surfactant, then stored in an ultrasonic stirrer and stirred for 4 hours to obtain a magnetic flake dispersion liquid.

650 cc of water is 10 g of gelatin (isoelectric point pH 4.5)
Then, after mixing with 10 g of gum arabic and stirring, the mixture was heated to 40 ° C. for facilitating the reaction to obtain a gelatin gum mixed solution which became the binder 31 of the microcapsule layer 30 .

The gelatin rubber mixed solution was stirred at a stirring speed of 1300 rpm and the magnetic flake dispersion was added little by little, and the stirring was continued for another 70 minutes to obtain an intermediate dispersion of pH 6.0. It was regarded as a liquid.

To the intermediate dispersion liquid, 10% by weight of acetic acid aqueous solution was added dropwise to pH 4 while continuing stirring, and further 1300
Stirring was continued for 30 minutes at a stirring speed of revolutions / minute. This formed a coacervate film of gelatin and gum arabic around the fine particles of the magnetic flake dispersion (substantially liquid paraffin). Further, after 30 minutes, the intermediate dispersion was cooled to 10 ° C., whereby the gelatin and gum arabic coacervate film formed around the fine particles of the magnetic flake dispersion was solidified. ..

In the intermediate dispersion liquid cooled to 10 ° C., gelatin formed around fine particles of the magnetic flake dispersion liquid (substantially liquid paraffin) by binding to deprotonated amino groups in gelatin and For the purpose of further coagulating the gum arabic coacervate film, formaldehyde was added in an appropriate amount to form a microcapsule solution.

To the microcapsule solution, 20% by weight aqueous sodium carbonate solution was added dropwise to pH 9.5 for the purpose of promoting desorption of protons from amino groups in gelatin while continuing stirring. The stirring was continued for another 24 hours, and the microcapsules were allowed to stand for 24 hours so as to be suspended.

The microcapsules suspended in the stationary microcapsule liquid (that is, floating capsules) were taken out, and pure water was added thereto to obtain a floating capsule liquid.

The floating capsule liquid was stirred and then placed in a magnetic field to separate and remove empty capsules.

In the floating capsule liquid from which the empty capsules were removed, the residual amount of empty capsules was determined in the residual capsule amount determination step.

The floating capsule liquid was repeatedly processed by the step of adding pure water or the step of determining the remaining amount of empty capsules until the remaining amount of empty capsules became a predetermined value or less.

The floating capsule liquid from which the empty capsules were sufficiently removed was adjusted to have a microcapsule content concentration of 50% by weight, and then the surface of the polyethylene terephthalate film as a transparent substrate (adhesive was previously attached The coating solution was applied to the above, heated to 80 ° C. and heat-treated for 30 minutes to be dried and solidified to form a microcapsule layer.

The surface of the microcapsule layer provided on the polyethylene terephthalate film as the transparent substrate is adhesive (pre-attached to the other surface of the polyethylene terephthalate film provided with a black magnetic layer on one surface). , And then heat-treated at 120 ° C. for 30 minutes to obtain a visible display device. Two identical visual display devices were created.

In one of the visible display devices, the magnetic flakes contained in the microcapsules in the microcapsule layer are formed by making the magnetization direction in the magnetic recording region of the magnetic sheet parallel to the surface of the magnetic sheet by an external magnet. It was oriented in a direction parallel to the surface of the magnetic sheet.
The lightness index L _{P at} this time is calculated by a lightness difference meter (manufactured by Suga Test Instruments Co., Ltd., SM Color Computer, SM-5, photometric area).
It was 45.0 as measured by 0.20 cm ² .

On the other side of the visible display device, the magnetic flakes contained in the microcapsules in the microcapsule layer are formed by setting the magnetization direction in the magnetic recording area of the magnetic sheet to be the direction perpendicular to the surface by the external magnet. It was oriented in a direction perpendicular to the surface of the magnetic sheet. The lightness index L _{V at} this time was 15.0 as measured by the above-mentioned lightness difference meter.

[0071] Thus, the contrast K of visual display device of the time (= L _P -L _V) was 30.0.

Each of the two visible display devices is maintained at 50 ° C. with the magnetic flakes contained in the microcapsules in the microcapsule layer oriented in the directions parallel and orthogonal to the surface of the magnetic sheet. It was stored in a thermostatic chamber, taken out after 14 days, and the brightness index L _P and the brightness index L _V were measured in the same manner as above.
It was 4.9 and 15.0.

[0073] Thus, the contrast K of visual display device of the time (= L _P -L _V) is 29.9, was hardly changed even housed for 14 days in a constant temperature bath.

Comparative Example

The example was repeated to make a visual display device, except that dodecylbenzene was used instead of liquid paraffin. The same visual display device is 2
One was created.

The two visible display devices each have a lightness index L _P with the magnetic flakes contained in the microcapsules in the microcapsule layer oriented in directions parallel and orthogonal to the surface of the magnetic sheet. And the lightness index L _V were measured in the same manner as in the Examples, and were 45.0 and 15.0.

[0077] Thus, the contrast K of visual display device of the time (= L _P -L _V) was 30.0.

Each of the two visible display devices was maintained at 50 ° C. with the magnetic flakes contained in the microcapsules in the microcapsule layer oriented in the directions parallel and orthogonal to the surface of the magnetic sheet. The sample was stored in the thermostatic chamber, taken out after 14 days, and the brightness index L _P and the brightness index L _V were measured in the same manner as in the example.
It was 25.0 and 15.0.

Therefore, the contrast K (= L _P −L _V ) of the visible display device at this time was 10.0, which was greatly changed as it was stored in the constant temperature bath for 14 days.

Comparison of Example and Comparative Example

As is clear from the comparison between the example and the comparative example, according to the present invention, since the oil contained in the microcapsules of the microcapsule layer is formed by liquid paraffin, the influence of disturbance is almost eliminated. It can be prevented from being received, the contrast of the visible display area can be stably maintained, and the recorded content recorded in the magnetic recording area of the magnetic sheet can be stably and clearly displayed visually for a long period of time.

(Modification)

In the above description, the case where the base material 42 of the magnetic sheet 40 is transparent and the magnetic layer 41 has a dark color has been described, but the present invention is not limited to this, and the magnetic sheet is not limited thereto. It also includes cases where the substrate of is opaque and has a dark color (for example, black). In this case, the color of the magnetic layer of the magnetic sheet may be a bright color.

[0084]

As is apparent from the above, the visual display device according to the present invention accommodates, together with oil, magnetic flakes whose orientation direction can be changed according to a magnetic field, as clearly shown in [Means for Solving Problems]. The multiple microcapsules whose visible incident light reflection direction changes depending on the orientation direction are dispersed in a binder placed against the surface of the transparent substrate to form a microcapsule layer, which serves as the visible display area. A visual display device, in particular, because the oil is formed by liquid paraffin, (i)
It has the effect of stably orienting the magnetic flakes, and eventually (ii) has the effect of stabilizing the visible display, and consequently (iii) has the effect of making the visible display clear.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view showing an embodiment of a visual display device according to the present invention.

FIG. 2 is a partially enlarged cross-sectional view showing an enlarged part of the embodiment shown in FIG.

FIG. 3 is a partially enlarged cross-sectional view showing an enlarged part of the embodiment shown in FIG.

4A is a flowchart showing an example of a manufacturing procedure of the embodiment shown in FIG. 1. FIG.

FIG. 4B is a flow chart diagram showing an example of a manufacturing procedure of the embodiment shown in FIG. 1.

[Explanation of Codes] 10 : Visible display device 20: Transparent substrate 30・ ・ ・ ・ ・ Microcapsule layer 31 ・ ・ ・ Binder 32 ・ ・ ・ ・ ・・ ・ ・ ・ Microcapsules 33 ・ ・ ・ ・ ・ Liquid paraffin 34 ・ ・ ・ Magnetic flakes 40・ ・ ・Magnetic sheet 41 Magnetic layer 42 ···Base material

Claims (1)

[Claims] 1. A plurality of microcapsules, which contain magnetic flakes whose orientation direction is changed according to a magnetic field together with oil, and whose reflection direction of visible incident light is changed according to the orientation direction, are formed on the surface of a transparent substrate. A visible display device in which oil is formed by liquid paraffin (33) in a visible display device in which a microcapsule layer is formed by being dispersed in a binder arranged opposite to it to form a visible display region.