JP2000258758A - Liquid crystal film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal film which can be processed according to the user's desire, which is flexible and cut into any shape and which can be driven at low voltage by sandwiching a mixture with two transparent conductive films while the conductive faces face each other. SOLUTION: A liquid crystal and a polymer network substance such as a UV curing resin are weighed, to which plastic beads or glass beads as a spacer are added in a small amt. and mixed to prepare a liquid crystal mixture 8. Then the liquid crystal mixture 8 is applied on a transparent conductive film 5 produced by forming a transparent conductive layer 2 such as an ITO film on the film surface of polyether sulfone or the like. The films are stacked with the transparent conductive layers 2 facing each other. Thus, the liquid crystal mixture 8 is held between the two transparent conductive films 5. The laminate is irradiated with UV rays while uniformly pressurized on both sides by using glass plates 9, pressurizing clips 10 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible liquid crystal film for controlling scattering and transmission of light at a low voltage.

[0002]

2. Description of the Related Art Conventionally, in a glass product for controlling scattering and transmission, which is known as a dimming glass, it has not been possible to apply it to a portion where a curvature occurs or a portion requiring a fine structure. . Therefore, a dimming system using a liquid crystal has been studied. For example, FIG. 11 is a schematic diagram for explaining an example of a dimming system using liquid crystal.
FIG. 11A shows a state where a voltage is applied, and FIG. 11B shows a state where a voltage is not applied. In the figure, A is incident light, B is outgoing light, and C is a liquid crystal injection part. As shown in FIG. 1, a conventional light control system using liquid crystal includes a pair of transparent electrodes 2 and 2 and a liquid crystal array 3 between two parallel polarizing plates 1 and 1 separated by a predetermined distance. Is the mainstream structure. The transparent and opaque state of the liquid crystal is controlled depending on whether or not a voltage is applied to the voltage applying unit 4 connected to the transparent electrodes 2 and 2. In the case of the structure shown in FIG.
In this case, the liquid crystal becomes opaque, the light is blocked, and the entire device becomes black, so that the light environment becomes dark. On the other hand, when no voltage is applied (b), the liquid crystal is in a transparent state, and light is transmitted.

[0003]

However, in the configuration of the conventional dimming system shown in FIG.
A voltage close to V is required, and low voltage driving is desired also from the viewpoint of safety. In addition, there is a problem to be solved that the cutting process into a flexible and arbitrary shape is not sufficiently performed so that it can be provided easily and inexpensively in a wide range of fields. Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a liquid crystal film that can be post-constructed as desired, can be cut into a flexible and arbitrary shape, and can be driven at a low voltage.

[0004]

In order to solve the above-mentioned problems, a liquid crystal film according to the present invention is a liquid crystal film that can be cut into an arbitrary shape. A mixture of a spacer and a polymer for separation into two, a transparent conductive film having a conductive surface, and a connection to the two transparent conductive films so that a voltage can be applied to the mixture. It has an electrode, and the two transparent conductive films sandwich the mixture such that their conductive surfaces face each other.

[0005] Preferably, the polymer is an ultraviolet curable resin.

[0006] Preferably, the spacer is made of resin beads or glass beads having a particle size of 5 to 50 microns, and the thickness of the transparent conductive film is 20 to 200 microns.

[0007] Preferably, a dye, a fluorescent substance or a phosphorescent substance is added to the mixture.

[0008] Preferably, at least one conductive surface of the two transparent conductive films is patterned into an arbitrary shape.

Preferably, a diffraction grating film is in close contact with a surface of the two transparent conductive films which is different from at least one conductive surface.

Preferably, the electrode is connectable to a solar cell, and the solar cell is a flexible solar cell or an amorphous solar cell, more preferably a transmissive solar cell, and the two transparent conductive cells. The film can be used in close contact with at least one of the films.

[0011]

FIG. 1 is a schematic sectional view showing an example of a liquid crystal film according to the present invention. In the figure, reference numeral 100 is an example of a liquid crystal film according to the present invention. Reference numeral 2 denotes a transparent electrode (a glass transparent electrode,
Reference numeral 3 denotes a liquid crystal, 4 denotes a power supply (voltage applying unit), 5 denotes a transparent conductive film, 6 denotes an ultraviolet curable resin, and 7 denotes a spacer. Further, in the drawing, the orientation of the liquid crystal is indicated by whether a plurality of short lines in the liquid crystal drawn in a circle are arranged in parallel or irregularly. Hereinafter, a liquid crystal film according to the present invention based on such a configuration will be described.

In order to realize a flexible liquid crystal film, a combination of a liquid crystal and a polymer is selected so that the liquid crystal becomes an independent granular liquid crystal having a substantially constant size in a matrix polymer. By using a combination with a polymer, the orientation of the liquid crystal can be rotated in the polymer. For example, as shown in FIG. 1, a transparent polymer typified by the ultraviolet curable resin 6 and a liquid crystal (for example, E7 of Merck Japan) which has been widely and conventionally used may be used. The scattering efficiency of liquid crystal in visible light increases when the particle size is about 0.5 μm, but it is easy to obtain a liquid crystal having such a particle size in a liquid crystal mixture. By fixing the granular liquid crystal 3 to a transparent polymer network (ultraviolet curing resin 6) and sandwiching it with a transparent conductive film 5 held in parallel by a transparent spacer 7 of the order of 10 microns (5 to 50 microns), A liquid crystal light control film is produced. Since the matrix itself can be cured while containing the liquid crystal in order to enable cutting processing of an arbitrary shape, the ultraviolet curing resin itself used as an optical adhesive is used as a network here.
In order to make the voltage applied from the voltage applying unit 4 to the liquid crystal 3 uniform, the spacing between the electrodes 2 of the transparent conductive film 5 must be made uniform.
The configuration using the spacer of the present invention has an effect that short circuit does not occur even when the liquid crystal light control film is cut, an electrode interval is reduced, and a low voltage driving is performed.

Specifically, a liquid crystal mixture containing a liquid crystal, an ultraviolet curable resin, and a spacer is sandwiched with the conductive surfaces of the transparent conductive film facing each other and irradiated with ultraviolet light, whereby the whole or a part of the liquid crystal mixture is irradiated. Solidifies while being integrated with the transparent conductive film. By subjecting the transparent conductive film to electrode processing, a liquid crystal film can be easily realized.

When no voltage is applied, the orientation of the liquid crystal is not uniform as shown in FIG. 1A (actually, it is oriented along the interface), and the liquid crystal exhibits an opaque state. , So that it becomes transparent as shown in FIG. 1B.

For further environmentally friendly power saving measures,
The solar cell can be introduced into the voltage applying unit 4.

Example 1 Next, a method for manufacturing a liquid crystal film according to the present invention will be described.

FIGS. 2 and 3 are views for explaining an example of a method for producing a liquid crystal film according to the present invention. FIGS. 2 (a) to 2 (d) and 3 (e) to 3 (h) show It is a figure corresponding to a process.

First, a liquid crystal and a polymer network material typified by an ultraviolet curable resin are weighed, and 10 μm is measured.
A small amount of a plastic bead or a glass bead having a diameter of about m is added as a spacer, and the mixture is stirred and mixed to prepare a liquid crystal mixture 8 (FIG. 2A). Next, the liquid crystal mixture 8 is placed on a transparent conductive film 5 in which a transparent conductive layer 2 such as an ITO film is formed on a film surface such as polyethersulfone (FIG. 2B). Further, the transparent conductive film 5 on which the transparent conductive layer 2 is formed is attached to two transparent conductive layers 2,
2 are laminated so as to face each other (FIG. 2C). Thus, the liquid crystal mixture is sandwiched between the two transparent conductive films 5.

With respect to the laminated sandwich obtained in this way, a pressing clip 1
10 mW / cm ² while applying a uniform pressure using
UV irradiation is performed for about 5 minutes (FIG. 2D).
The ultraviolet curable resin containing the liquid crystal and the spacer solidifies, and the film (the liquid crystal composition becomes cloudy.
0) (FIG. 3E). When the ultraviolet curing resin is not used, it naturally follows the solidification conditions of the substance. In the electrode processing, for example, the remaining uncured portion is cleaned by masking ultraviolet rays (FIG. 3F),
The copper foil 11 may be attached to the conductive surface using the conductive adhesive tape 15 or the like (FIG. 3 (g)). However, it is assumed that a treatment such as cutting is performed so that the electrode portion does not touch the conductive surface of the other transparent conductive film opposed to the conductive film. In this way, a liquid crystal film as shown in FIG. 3E to 3H, reference numeral 1
Reference numerals 2, 13, 14, and 15 indicate a cutting line, an electrode extraction portion, and a portion that cuts only one surface (an adhesive such as an epoxy resin for reinforcing against peeling of the film at the end surface, or a cellophane tape for convenience). Is valid).

Further, in order to increase the area which is industrially important,
A roller system including an ultraviolet irradiation step can be used.

When an AC voltage of about 30 V is applied to the produced liquid crystal film, the cloudy scattering state becomes instantaneously transparent. Of course,
When the voltage application is canceled, the state immediately returns to the cloudy scattering state. Even when the composition of the liquid crystal mixture was changed at 40 to 60% by weight, good characteristics were obtained. The 70% by weight sample has a low white turbidity, which is not practically sufficient under the same manufacturing conditions. However, since a plurality of samples can be used, even a sample of 70% by weight or less can be used in combination. Can be used.

Since the liquid crystal film thus manufactured is flexible, it can be used on a curved surface as described below.

FIGS. 4 and 5 show examples of the use of the liquid crystal film having the above structure. FIG. 4 is a schematic diagram showing an example of a photo frame in which visualization and invisibility of a private photograph can be realized with one touch. In the figure, reference numeral 16 denotes a portion where a background photograph is visualized by applying a voltage (a surface photograph is superimposed on a background photograph), and 17 denotes a portion where no voltage is applied (a surface photograph with a cloudy portion as a background). FIG.
Shows the configuration of the photo frame shown in FIG. 4. In the drawing, reference numeral 18 is a liquid crystal film, 19 is a background photograph, and 20 is a surface photograph (OHP). That is, in FIGS. 4 and 5, the liquid crystal film 13
A photo frame is shown, in which a voltage application unit capable of controlling the visualization and invisible state of the background photo 14 by superimposing an OHP photo 15 thereon is shown. In this example, a portion where no voltage is applied has a fixed background or photograph.

Although there has been no such use example, it can be easily realized by the present invention. Further, when used for a photograph, a poster, a bromide, an illustration, a calendar, a clock, a mirror, or the like, a double photograph can be easily realized depending on whether or not a voltage is applied to the liquid crystal film. In addition to a photo frame that allows the visualization and invisibility of private photos with a single touch, multiplexing of image information such as slides can be easily enjoyed. Further, when such a configuration is enlarged, a function of making all or a part of a partition, a door, a display case, or the like visible or invisible can be realized.

Example 2 Next, processing of a liquid crystal film produced by the above-described method will be briefly described with reference to FIG. FIGS. 6 (a) to 6 (c)
The cutting process of a liquid crystal film is shown.

FIG. 6A shows an example of the liquid crystal film 21. Even if the liquid crystal film 21 is cut along a cutting line 22 with a cutter knife 23 or scissors 24 to form a liquid crystal film 25 cut into an arbitrary shape, or even if the liquid crystal film 25 is cut more and more times, a phenomenon such as a short circuit occurs. I was not able to admit. That is, the liquid crystal film 25 shown in FIG.
Retains the initial performance, and the effect of cutting is not recognized at all. Further, low-voltage driving of about 30 V is possible.

From the above, it has been clarified that the present invention can provide a flexible, low power consumption liquid crystal film which can be post-processed as desired by the user and which can be cut into arbitrary shapes. In the case where the peeling of the film on the end face is a concern as described above, the reinforcement may be performed by using the method described in the first embodiment.

Since the light control film in Example 1 is easily cut, the shape of the liquid crystal film is as desired.

[Embodiment 3] In Embodiments 1 and 2, if the conductive surface of the conductive film is subjected to patterning including a dot matrix in advance, only the liquid crystal mixing portion in contact with the patterned conductive surface is obtained. Can be switched between cloudy and transparent. Since the other parts remain cloudy, the display function can be realized as shown in FIG. When a mirror or a colored background is used, characters and illustrations seen in the transparent part can be enjoyed as the background color. FIG. 7 shows a conductive surface which is made transparent by applying a voltage via the lead wire 26 as a black portion. This part shows the background color by making it transparent. Since no voltage is applied to portions other than the black portion, the portion remains cloudy.

Example 4 In Examples 1 to 3,
When a dye, a fluorescent substance, and a luminous substance are added to the liquid crystal mixture in advance, the liquid crystal can be partially colored, so that a desired color and tone can be realized. In addition, since other colors and color tones can be used for the background visualized by the black portion in FIG. 6, a combination of these colors and colors can be further varied.

Example 5 In Examples 1 to 4,
A film for forming a transmission type diffraction grating on one or both sides of the liquid crystal film 29 (diffraction grating films 27, 3)
When 1) is closely attached, the spectral effect can be used. It is possible to realize a light control film or a display sheet in which an iridescent transmission part is obtained on a cloudy surface or a background surface having another color. FIG. 8 is a schematic view showing a case where the transmission diffraction grating films 27 and 31 are respectively introduced outside the liquid crystal film. Obviously, brighter transmission characteristics can be obtained by using the diffraction grating film 27 or 31 only on one side, but the spectral characteristics become steeper when used on both sides, so that it may be selected according to the use conditions. The figure shows a case where the engraved portions 28 and 30 are used on both sides with the outer sides.

[Embodiment 6] In Embodiments 1 to 5,
The voltage applied to the liquid crystal mixture is changed to solar power (solar cell 2
This is performed using the electricity obtained in 1). It can be easily understood that the present invention is effective in places where a dimming function is required, from houses, trains and automobiles to window glasses, skylights, and sunroofs. This not only contributes to cooling and heating,
Energy saving can be achieved even when using the blind function and display function. FIG. 9 and FIG. 10 schematically show this example.

FIG. 9A shows an example in which the power supply for applying voltage to the liquid crystal film 33 is simply replaced by a solar cell 32. Regarding the examples shown here, direct current and alternating current do not matter, but when using alternating current, it is assumed that parts required for alternating current are also included. FIG. 9B shows an example in which a solar cell is disposed immediately near the liquid crystal film 33. FIG. 9C shows a case where the solar cell is in contact with the liquid crystal film 33. 9 (a) to 9 (c)
In, there is no limitation on the type of solar cell, such as whether the crystal is amorphous, flexible, or transmissive.

FIG. 10D schematically shows an example in which the liquid crystal film 33 and the solar cell 32 are in contact with each other. Here, the dimming function of the liquid crystal film 33 acts on the sunlight passing through the solar cell 32, so that the transmission type is indispensable. Furthermore, since the liquid crystal film 33 is characterized by being flexible, it is desirable that the solar cell 32 be also flexible in order to make use of this characteristic. Therefore, although not necessarily limited, the introduction of an amorphous transmission solar cell is optimal.

FIG. 10E shows a combination of the photovoltaic power generation and the power storage function, and FIG. 10F shows a combination with the existing power supply such as a commercial power supply or a battery. The liquid crystal film 33 and the solar cell 32 may be apart from or in contact with each other, but FIG. At night or when the weather is bad, solar power generation cannot be used. In this case, however, since the existing power supply and the battery 34 are provided, they can be operated without any problem by switching the power supply.

As described in the first to sixth embodiments, the present invention enables post-processing according to the user's request.
A liquid crystal film that is flexible and can be cut into an arbitrary shape can be realized. As a light control film that can be driven at a low voltage of about 30 V, it can be easily used as an interior product or a liquid crystal film with a display function, and can be applied to places that have post-construction or curvature that were not possible with conventional products. Becomes possible. This dramatically improves the design and leads to a reputation as a product having an accessory function.

Although the use of the materials shown in each embodiment is not particularly limited, for example, a patterned material, a dye, or a material to which a fluorescent or luminous substance is added is particularly useful for improving the display function. I do. In addition, those requiring an accessory function can be expected to use a diffraction grating film in close contact.

Further, the combined use of solar cells leads to energy saving.

If necessary, turn on / off the voltage application switch.
By ff, scattering and transmission of light can be switched, and application as a screen of a movie or slide can be made from both front and back directions. Further, it can also be used for partitioning applications such as partitions and blinds that can be separated into a transparent state and a frosted state by a person entering and exiting. Since the user can easily cut this liquid crystal film into any shape,
Post-construction is possible, such as pasting to a desired location as needed. We can expect the application as an interior that changes the living environment with a sense of play. In addition, a combination of a solar cell and a liquid crystal film can be expected as a contribution to energy saving and power saving by approaches from recent environmental issues.

[0040]

As described above, the liquid crystal film according to the present invention is a liquid crystal film that can be cut into an arbitrary shape, and includes a liquid crystal and a spacer for separating the liquid crystal into a group consisting of a plurality of granular liquid crystals. , And a mixture of polymers, two transparent conductive films having a conductive surface, and an electrode connected to the two transparent conductive films so that a voltage can be applied to the mixture, and Since the two transparent conductive films are characterized in that the mixture is sandwiched such that the respective conductive surfaces face each other, it is flexible and can be post-installed according to a user's request. A liquid crystal film that can be cut into an arbitrary shape and that can be driven at a low voltage can be provided.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic cross-sectional views for explaining a configuration example and operation of a liquid crystal which returns to the present invention. FIG. 1A is a state where no voltage is applied, and FIG. 1B is a state where a voltage is applied. Is shown.

FIGS. 2A to 2D are schematic views for explaining an example of a method for manufacturing a liquid crystal film according to the present invention, wherein FIGS.
Indicates each step.

FIG. 3 is a schematic view for explaining an example of a method for producing a liquid crystal film based on the present invention, and (e) to (h).
Indicates the steps following (a) to (d) in FIG.

FIG. 4 is a schematic view for explaining an example of use of a liquid crystal film according to the present invention.

FIG. 5 is a schematic diagram for explaining an example of use of a liquid crystal film according to the present invention.

FIG. 6 is a schematic diagram for explaining an example of cutting a liquid crystal film according to the present invention, wherein (a) to (c) show cutting steps.

FIG. 7 is a schematic diagram for explaining a display function of a liquid crystal film according to the present invention.

FIG. 8 is a schematic diagram for explaining an example of applying a transmission type diffraction grating film to a liquid crystal film according to the present invention.

FIG. 9 is a schematic diagram for explaining an example in which a solar cell is applied to a liquid crystal film according to the present invention, and (a) to (c) show each example.

FIG. 10 is a schematic diagram for explaining an example in which a solar cell is applied to a liquid crystal film according to the present invention, and FIGS. 9 (d) to 9 (f) show each example as in FIGS. 9 (a) to 9 (c). Show.

11A and 11B are schematic diagrams illustrating an example of a conventional liquid crystal film, wherein FIG. 11A illustrates a state where a voltage is applied, and FIG. 11B illustrates a state where a voltage is not applied.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 polarizing plate 2 transparent electrode (including glass transparent electrode and conductive surface of conductive film) 3 liquid crystal 4 power supply (voltage applying unit) 5 transparent conductive film 6 ultraviolet curing resin 7 spacer 8 liquid crystal mixture 9 glass plate 10 pressure clip Reference Signs List 11 Copper foil 12 Cutting line 13 Electrode take-out part 14 Cut part 15 Conductive adhesive tape 16 Visualization of background photograph by applying voltage (surface photograph superimposed on background photograph) 17 No voltage application (surface photograph with cloudy part as background) ) Portion 18 liquid crystal film 19 background photograph 20 surface photograph (OHP) 21 liquid crystal film 22 cutting line 23 cutter knife 24 scissors 25 liquid crystal film 26 lead wire 27 diffraction grating film 28 scribed line 29 liquid crystal film 30 scribed line 31 diffraction Lattice film 32 Solar cell 33 Liquid crystal film 34 Battery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H01L 31/04 H01L 31/04 Q (72) Inventor Kenji Ota 3-chome 19, Nishishinjuku, Shinjuku-ku, Tokyo No. 2 Nippon Telegraph and Telephone Corporation (72) Inventor Shinji Tsuru 1-3-1 Gotenyama, Musashino City, Tokyo NTT Advanced Technology Co., Ltd. (72) Inventor Fumio Yamamoto Musashino, Tokyo 1-3-3 Gotenyama-shi, NTT F-Term (NTT Advanced Technology) 2H049 AA02 AA60 AA64 2H088 EA02 EA67 FA05 FA09 FA29 GA10 HA01 JA04 MA16 MA17 2H089 HA04 KA08 KA15 LA07 LA19 NA22 NA58 QA11 QA14 RA04 TA01 TA03 2H091 FA48Y FB09 FC27 FD02 FD13 GA01 GA03 HA06 JA02 LA11 5F051 AA05 CA15 FA04 GA05

Claims (10)

[Claims] 1. A liquid crystal film that can be cut into an arbitrary shape, comprising: a liquid crystal; a spacer for separating the liquid crystal into a group of a plurality of granular liquid crystals; and a mixture of a polymer; A transparent conductive film, and an electrode connected to the two sheets of the transparent conductive film and capable of applying a voltage to the mixture, further comprising: A liquid crystal film, wherein the mixture is sandwiched such that conductive surfaces face each other. 2. The liquid crystal film according to claim 1, wherein the polymer is an ultraviolet curable resin. 3. The method according to claim 1, wherein the spacer is made of resin beads or glass beads having a particle diameter of 5 to 50 microns, and the transparent conductive film has a thickness of 20 to 200 microns. The liquid crystal film as described. 4. The liquid crystal film according to claim 1, wherein a dye, a fluorescent substance, or a phosphorescent substance is added to the mixture. 5. The liquid crystal film according to claim 1, wherein at least one conductive surface of the two transparent conductive films is patterned into an arbitrary shape. 6. The diffraction grating film according to claim 1, wherein a diffraction grating film adheres to a surface of the two transparent conductive films different from at least one conductive surface. The liquid crystal film as described. 7. The liquid crystal film according to claim 1, wherein the electrode is connectable to a solar cell. 8. The liquid crystal film according to claim 7, wherein the solar cell is a flexible solar cell. 9. The liquid crystal film according to claim 7, wherein the solar cell is an amorphous solar cell. 10. The liquid crystal film according to claim 8, wherein the solar cell is a transmission type solar cell and is used in close contact with at least one of the two transparent conductive films.