JPH04116827U - dimming liquid crystal sheet - Google Patents

Abstract

(57) [Summary] [Purpose] A dimming liquid crystal in which the transparent electrode near the collector electrode formed at the edge of the transparent electrode surface of the transparent electrode film does not break even when a voltage is applied for a long time and the transparent state is maintained. Provide sheets. [Structure] Transparent electrode films 2a, 2 on both sides of the liquid crystal layer 1
B are stacked so that the transparent electrode surfaces 3a, 3a are on the inside, and a metal foil tape 40 with a conductive carbon-containing adhesive 41 is attached to the edges of the transparent electrode surfaces 3a, 3b to form a collector electrode 4a. , 4b.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention can be used in various applications such as blinds, skylights and window lighting materials, displays, and room partitions. This invention relates to improvements in light control liquid crystal sheets used for light control applications.

0002

[Conventional technology]

As this type of light control liquid crystal sheet, the applicant has developed one with the structure shown in Figure 5. uttered. This light control liquid crystal sheet has transparent electrode films 2a and 2b on both sides of the liquid crystal layer 1. are laminated together so that the transparent electrode surfaces 3a and 3b are on the inside, and the transparent electrode A conductive paste is applied to the edges of the pole surfaces 3a and 3b and dried to form strip-shaped collector electrodes 4a and 4. b is formed. A terminal piece 5a for connecting a lead wire is attached to each collector electrode 4a, 4b. , 5b with conductive adhesive or the like, and cover the periphery of the sheet with insulating tape 6. There is.

0003 Such a light control liquid crystal sheet has a state in which no voltage is applied between the transparent electrode surfaces 3a and 3b. In this state, the liquid crystal layer 1 scatters the transmitted light and becomes cloudy, but when voltage is applied to the terminal pieces 5a and 5b, When applied, a uniform electric field is applied to the entire transparent electrode surfaces 3a and 3b by the collector electrodes 4a and 4b. The liquid crystal molecules in the liquid crystal layer 1 become oriented in the direction of the electric field and become transparent. Used for various light control applications.

0004

[Problem that the idea aims to solve]

However, if the conductive paste is applied and dried to form the collector electrodes 4a and 4b, In addition to being time-consuming, there is the problem that both collector electrodes cannot be formed at the same time. There was also the problem that the working environment deteriorated due to solvent volatilization from the burner.

[0005] Therefore, we pasted metal foil tape with conductive adhesive to form the collector electrodes 4a and 4b. However, conductive adhesive containing metal powders such as silver, copper, and nickel adhered to the product. When using a metal foil tape, the transparent electrode near the collector electrode was removed within one week during the current test. A problem arose in which the wire broke and it was not possible to obtain a reliable dimming liquid crystal sheet. .

[0006]

[Means to solve the problem]

This invention was made to solve the above problem, and transparent electrode films are placed on both sides of the liquid crystal layer. In a dimming liquid crystal sheet in which the transparent electrodes are stacked with the transparent A metal foil tape with conductive carbon-containing adhesive is attached to the edge of the bright electrode surface to form a collector electrode. It is characterized by the formation of

[0007]

[Effect]

As shown in FIG. 4, a metal foil tape 40 with a conductive adhesive 42 containing metal powder is attached. The transparent electrode surface 3 of the transparent electrode film 2 (for example, the transparent electrode surface formed of ITO) When forming the collector electrode 4 by pasting it on the edge, the electrical conductive adhesive 42 containing metal powder Since the resistance r is much smaller than the electrical resistance R between PQ on the transparent electrode surface 3, the current is The flow will be concentrated at point Q as shown by the arrow. Therefore, Q points within a short period of time A crack occurs and grows from that part, and the transparent electrode near point Q is disconnected.

[0008] On the other hand, as in the present invention shown in FIG. When the collector electrode 4 is formed by pasting the metal foil tape 40 on the edge of the transparent electrode surface 3, The electrical resistance r of the conductive carbon-containing adhesive 41 is the electrical resistance between PQ of the transparent electrode surface 3. Since it is not much different from R, the current is not concentrated at point Q as shown by the arrow, but is This prevents disconnection of the transparent electrode near point Q due to the occurrence of cracks. .

[0009]

【Example】

Embodiments of the present invention will be described below with reference to the drawings.

0010 FIG. 1 is a plan view showing one embodiment of the present invention's light control liquid crystal sheet, and FIG. 2 is the line A-B in FIG. It is an enlarged sectional view taken along the line CD.

[0011] This light control liquid crystal sheet has transparent electrode films 2a and 2b on both sides of the liquid crystal layer 1. The transparent electrode surfaces 3a and 3b are integrated into one layer on the inside, and the upper transparent electrode The polar film 2a has one edge (the right edge in the figure) of the transparent electrode surface 3a exposed, and the lower The other edge (the left edge in the figure) of the side transparent electrode film 2b is exposed on the transparent electrode surface 3b. ing. The exposed edges of these transparent electrode surfaces 3a and 3b contain conductive carbon. When metal foil tape 40 with adhesive 41 is attached to form collector electrodes 4a and 4b, Both conductive terminal pieces 5a and 5b for connecting lead wires are connected to the respective collector electrodes 4a and 4b. The sheet is adhered with adhesive or the like, and the periphery of the sheet is covered with an insulating tape 6.

0012 The liquid crystal layer 1 is made of thermosetting epoxy resin, photocuring acrylic resin, Epoxy resin, ene thiol resin, etc. with nematic liquid crystal and microbeads A mixture prepared by mixing appropriate amounts of a curing agent and a photoinitiator is applied to the upper and lower transparent electrode films. Either sandwich it between the layers 2a and 2b and harden it by heat curing, light curing, natural curing, etc. Alternatively, the liquid crystal can be encapsulated using the above resins, polyvinyl alcohol resin, or acrylic resin. , apply a mixture dispersed in emulsion resin such as urethane, dry and harden. It was formed by chromatography. Therefore, in such a liquid crystal layer 1, Liquid crystals may spontaneously disperse in the form of droplets due to phase separation, or liquid crystals may be continuously connected. to form a continuous phase, resin to be dispersed in the form of droplets, and liquid crystals to form microcapsules. distributed as a group.

[0013] In addition, the transparent electrode films 2a and 2b are made of polyethylene terephthalate, polyester, etc. - Transparent wood with a thickness of about 50 to 200 μm such as telosulfone or polycarbonate Metal oxides such as crystalline or amorphous ITO or tin oxide are deposited on one side of the fat film. Alternatively, those in which transparent electrode surfaces 3a and 3b are formed by sputtering are preferably used. However, a transparent conductive paint is applied to one side of the above resin film to form a transparent electrode surface. Formed products are also used. The transparent electrode surfaces 3a and 3b are not necessarily pieces of resin film. It does not need to be formed on the entire surface, and may be formed in a certain design or pattern. Such a pattern is provided on either or both of the upper and lower transparent electrode films 2a and 2b. By using a transparent electrode film with a patterned transparent electrode surface, it is possible to It is possible to obtain a patterned dimming liquid crystal sheet whose design or pattern is transparent. In addition, weather resistance improved films, purple Composite transparent electrode film laminated with external ray cut film, heat ray cut film, etc. Of course, it is also possible to use

The collector electrodes 4a, 4b formed at the edges of the transparent electrode surfaces 3a, 3b of the transparent electrode films 2a, 2b serve to suppress the voltage drop on the transparent electrode surfaces 3a, 3b and generate a uniform electric field. The collector electrodes 4a and 4b are formed by pasting a metal foil tape 40 with a conductive carbon-containing adhesive 41 on the back side. Such a metal foil tape with a conductive carbon-containing adhesive is prepared by rolling a carbon-containing adhesive obtained by kneading conductive carbon powder into an acrylic, silicone, or rubber-based resin binder to a thickness of about 25 to 50 μm. A copper foil tape or a rolled aluminum foil tape coated on the back side with a thickness of about 30 to 60 μm is preferably used. Such a conductive carbon-containing adhesive-attached metal foil tape has a much higher electrical resistance than a conductive adhesive-attached metal foil tape containing metal powder, and has transparent electrode surfaces 3a and 3b formed of ITO or the like. It has an electrical resistance that is not much different from that of . For example, the electrical resistance of a conductive carbon-containing adhesive having a thickness of 45 μm is about 170 Ω/inch ² , which is approximately the same as the electrical resistance of the transparent electrode surface of ITO (usually about 300 to 400 Ω/cm ² ). On the other hand, the electrical resistance of a conductive adhesive containing nickel powder with a thickness of 40 μm is 0. 0.004Ω/inch ² , which is much smaller than the electrical resistance of ITO.

[0015] The terminal pieces 5a, 5b attached to the collector electrodes 4a, 4b may be metal foil tape or Thin metal flakes such as phosphor bronze, copper, and aluminum are preferably used, and A power wire is connected to the collector electrodes 4a, 4b. In addition, the insulating tape 6 is impregnated with moisture. This is to prevent power leakage, electric shock, and delamination of the light control sheet. For example, transparent polypropylene resin tape, polyethylene terephthalate resin Tape etc. are preferably used, but instead of this insulating tape 6, epoxy resin etc. A transparent insulating adhesive may be applied around the sheet.

[0016] The light control liquid crystal sheet having the above structure has transparent electrode films 2a and 2b. When no voltage is applied between the polar surfaces 3a and 3b, the orientation of the liquid crystal molecules in the liquid crystal layer 1 is Because it is random, the transmitted light is scattered and becomes cloudy, and when a voltage is applied, the liquid crystal content becomes cloudy. The particles align in the direction of the electric field and change to a light-transmitting state, becoming transparent. In this way, voltage is applied Even if the light transmitting state is maintained for a long time, the electrical resistance of this dimming liquid crystal sheet is Metal with conductive carbon-containing adhesive 41 that is not much different from pole surfaces 3a and 3b Since the collector electrodes 4a and 4b are formed by the foil tape 40, it is not explained in the operation section. As explained above, the current flows throughout without being concentrated at the Q point in FIG. in this way If the current is no longer concentrated at the Q point, no cracks will occur at the Q point even if the current is applied for a long time. Therefore, there is no fear that the transparent electrode near the Q point will be disconnected, and reliability is improved. actual When we conducted a continuous electricity test for 1 year on 10 dimming liquid crystal sheets, we found that they were disconnected. The result was that there were no lines.

[0017]

[Effect of the idea]

As is clear from the above explanation, the dimming liquid crystal sheet of the present invention is suitable for long-term voltage application. In addition, even if the light transmitting state is maintained, disconnection of the transparent electrode near the collector electrode can be prevented, making it reliable. This improves reliability, suppresses voltage drop on the transparent electrode surface, and maintains almost uniform electric field strength. It has the effect of

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of a light control liquid crystal sheet of the present invention.

FIG. 2 is an enlarged sectional view taken along the line ABCD in FIG. 1;

FIG. 3 is an explanatory diagram of a collector electrode forming portion of the light control liquid crystal sheet of the present invention.

FIG. 4 is an explanatory diagram of a collector electrode forming portion when the collector electrode is formed of a metal foil tape with a conductive adhesive containing metal powder.

FIG. 5 is a cross-sectional view of a conventional dimming liquid crystal sheet.

[Explanation of symbols]

1 Liquid crystal layer 2a, 2b transparent electrode film 3, 3a, 3b transparent electrode surface 4, 4a, 4b collector electrode 40 Metal foil tape with conductive carbon-containing adhesive 41 Conductive carbon-containing adhesive

Claims (1)

[Scope of utility model registration request] 1. A dimming liquid crystal sheet in which transparent electrode films are laminated on both sides of a liquid crystal layer with the transparent electrode surfaces facing inside, wherein a metal foil tape with a conductive carbon-containing adhesive is attached to the edge of the transparent electrode surface. A light control liquid crystal sheet characterized in that a collector electrode is formed by pasting.