# US 11,112,670 B2 · Light control film, light control system, and light control member

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- Number: US 11,112,670 B2
- Document ID: US11112670B2
- Status: Granted
- Kind: B2
- Application number: 16/488,807
- Filed: 2018-03-12
- Published: 2020-08-27
- Granted: 2021-09-07
- Earliest claimed: 2017-03-10
- Assignees: Dai Nippon Printing Co., Ltd.
- Applicants: Dai Nippon Printing Co., Ltd.
- Inventors: Makoto Yamaki; Tomoya Kawashima
- Web page: https://patentgrep.com/patent/US11112670B2

## CPC

- G02F 1/137: characterised by the electro-optical or magneto-optical effect, e.g. field-induced phase transition, orientation effect, guest-host interaction or dynamic scattering
- G02F 1/13725: {based on guest-host interaction (G02F1/13762, G02F1/13737, take precedence)}
- G02F 1/13718: {based on a change of the texture state of a cholesteric liquid crystal}
- G02F 1/133302: {Rigid substrates, e.g. inorganic substrates}
- G02F 2202/043: pleochroic
- Y02B 80/00: Architectural or constructional elements improving the thermal performance of buildings
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A light control film and a light control system, which not only simply change the amount of transmitted light but also can be used for a wider range of applications. This light control film includes a first electrode, a second electrode, a liquid crystal material, and a dichroic dye, and has a guest-host type liquid crystal layer in which light transmittance varies with the potential difference between the first electrode and the second electrode, wherein the liquid crystal layer has a first haze value when the potential difference is a first potential difference, has a second haze value when the potential difference is a second potential difference, and has a third haze value higher than at least the second haze value when the potential difference is a third potential difference between the first potential difference and the second potential difference.

## Claims

### Claim 1

A light control film, comprising:
a first electrode;
a second electrode; and
a liquid crystal layer that contains a liquid crystal material and a dichroic dye, and has a light transmittance varying in accordance with a potential difference between the first electrode and the second electrode,
wherein the liquid crystal layer,
has a first haze value in a case where the potential difference is a first potential difference being 0 V,
has a second haze value in a case where the potential difference is a second potential difference being 10 V, and
has a third haze value higher than at least the second haze value in a case where the potential difference is a third potential difference between the first potential difference and the second potential difference.

### Claim 2

A light control film, comprising:
a first electrode;
a second electrode; and
a liquid crystal layer that contains a liquid crystal material and a dichroic dye, and has a light transmittance varying in accordance with a potential difference between the first electrode and the second electrode,
wherein the liquid crystal layer,
is in a light shielding state in a case of a first potential difference in which the potential difference is 0 V,
is in a light transmitting state in which a transmittance is higher than that of the light shielding state in a case of a second potential difference in which the potential difference is greater than the first potential difference,
has a first haze value in a case of the first potential difference,
has a second haze value in a case of the second potential difference,
has a maximum haze value in a case of a third potential difference in which the potential difference is greater than the first potential difference, and the potential difference is less than the second potential difference, and
the maximum haze value is greater than the first haze value and the second haze value.

### Claim 3 (depends on 2)

The light control film according to claim 2, wherein, in the light control film, in a case where the potential difference is changed to the second potential difference from the first potential difference, a time until a transmittance is changed to 90% of the transmittance in the light transmitting state from the transmittance in the light shielding state is longer than or equal to 16 milliseconds.

### Claim 4 (depends on 2)

The light control film according to claim 2, wherein, when a thickness of the liquid crystal layer is set to d, a chiral pitch of liquid crystal molecules contained in the liquid crystal layer is set to p, d/p is greater than or equal to 1.1 (1.1≤d/p).

### Claim 5 (depends on 4)

The light control film according to claim 4, wherein d/p is greater than or equal to 1.1 and less than or equal to 2.7 (1.1≤d/p≤2.7).

### Claim 6 (depends on 2)

The light control film according to claim 2, wherein
the liquid crystal material has dielectric anisotropy, and
when a permittivity of the liquid crystal molecules of the liquid crystal material in a major axis direction is set to ε//, a permittivity of the liquid crystal molecules in a minor axis direction is set to ε⊥, and an absolute value of a difference between the permittivities is set to |Δε|=|ε//−ε⊥|, |Δε| is less than or equal to 100.

### Claim 7 (depends on 2)

A light control system, comprising:
the light control film according to claim 2; and
a control unit that changes the potential difference between the first potential difference and the second potential difference.

### Claim 8

A light control film, comprising:
a first electrode;
a second electrode; and
a liquid crystal layer that contains a liquid crystal material and a dichroic dye, and has a light transmittance varying in accordance with a potential difference between the first electrode and the second electrode,
wherein the liquid crystal layer,
is in a light transmitting state in a case of a first potential difference in which the potential difference is 0 V,
is in a light shielding state in which a transmittance is lower than that of the light transmitting state in a case of a second potential difference that is 10 V,
has a first haze value in a case of the first potential difference,
has a second haze value in a case of the second potential difference,
has a maximum haze value in a case of a third potential difference in which the potential difference is greater than the first potential difference, and the potential difference is less than the second potential difference, and
the maximum haze value is greater than the first haze value and the second haze value.

### Claim 9 (depends on 8)

The light control film according to claim 8, wherein, in the light control film, in a case where the potential difference is changed to the first potential difference from the second potential difference, a time until a transmittance is changed to 90% of the transmittance in the light transmitting state from the transmittance in the light shielding state is longer than or equal to 16 milliseconds.

### Claim 10 (depends on 8)

The light control film according to claim 8, wherein, when a thickness of the liquid crystal layer is set to d, and a chiral pitch of liquid crystal molecules contained in the liquid crystal layer is set to p, d/p is greater than or equal to 0.9 and less than or equal to 1.5 (0.9≤d/p≤1.5).

### Claim 11 (depends on 8)

The light control film according to claim 8, wherein
the liquid crystal material has dielectric anisotropy, and
when a permittivity of the liquid crystal molecules of the liquid crystal material in a major axis direction is set to ε//, a permittivity of the liquid crystal molecules in a minor axis direction is set to ε⊥, and an absolute value of a difference between the permittivities is set to |Δε|=|ε//−ε⊥, |Δε| is less than or equal to 100.

### Claim 12 (depends on 8)

A light control system, comprising:
the light control film according to claim 8; and
a control unit that changes the potential difference between the first potential difference and the second potential difference.

### Claim 13

A light control member, comprising:
a first laminate that includes a first base material and a first electrode;
a second laminate that includes a second base material and a second electrode; and
a liquid crystal layer that is clamped between the first laminate and the second laminate,
wherein
the first base material and the second base material are formed of glass,
the liquid crystal layer contains a liquid crystal material and a dichroic dye, and has a light transmittance varying in accordance with a potential difference between the first electrode and the second electrode,
the liquid crystal layer,
is in a light shielding state in a case of a first potential difference in which the potential difference is 0 V,
is in a light transmitting state in which a transmittance is higher than that of the light shielding state in a case of a second potential difference in which the potential difference is greater than the first potential difference,
has a first haze value in a case of the first potential difference,
has a second haze value in a case of the second potential difference,
has a maximum haze value in a case of a third potential difference in which the potential difference is greater than the first potential difference, and the potential difference is less than the second potential difference, and
the maximum haze value is greater than the first haze value and the second haze value.

### Claim 14

A light control member, comprising:
a first laminate that includes a first base material and a first electrode;
a second laminate that includes a second base material and a second electrode; and
a liquid crystal layer that is clamped between the first laminate and the second laminate,
wherein
the first base material and the second base material are formed of glass,
the liquid crystal layer contains a liquid crystal material and a dichroic dye, and has a light transmittance varying in accordance with a potential difference between the first electrode and the second electrode,
the liquid crystal layer,
is in a light transmitting state in a case of a first potential difference in which the potential difference is 0 V,
is in a light shielding state in which a transmittance is lower than that of the light transmitting state in a case of a second potential difference that is 10 V,
has a first haze value in a case of the first potential difference,
has a second haze value in a case of the second potential difference,
has a maximum haze value in a case of a third potential difference in which the potential difference is greater than the first potential difference, and the potential difference is less than the second potential difference, and
the maximum haze value is greater than the first haze value and the second haze value.