# US 11,442,322 B2 · Light control sheet and light control window

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- Number: US 11,442,322 B2
- Document ID: US11442322B2
- Status: Granted
- Kind: B2
- Application number: 16/877,644
- Filed: 2020-05-19
- Published: 2020-09-03
- Granted: 2022-09-13
- Earliest claimed: 2017-12-28
- Assignees: Toppan Printing Co., Ltd.
- Applicants: Toppan Printing Co., Ltd.
- Inventors: Tetsushi Yoshida
- Web page: https://patentgrep.com/patent/US11442322B2

## 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
- B60J 1/001: {Double glazing for vehicles}
- B60J 3/04: adjustable in transparency
- B60J 3/06: using polarising effect
- G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
- G02F 1/133528: {Polarisers}
- G02F 1/1337: Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
- G02F 1/13439: {characterised by their electrical, optical, physical properties; materials therefor; method of making}
- G02F 1/13725: {based on guest-host interaction (G02F1/13762, G02F1/13737, take precedence)}
- B60J 1/08: arranged at vehicle sides
- B60J 1/18: arranged at the vehicle rear {(optical viewing arrangements integrated in rear windows, e.g. Fresnel lenses B60R1/001)}
- G02F 1/133302: {Rigid substrates, e.g. inorganic substrates}
- G02F 1/13345: {Network or three-dimensional gels}
- G02F 1/133738: {for homogeneous alignment}
- G02F 2201/503: Arrangements improving the resistance to shock
- G02F 2202/043: pleochroic
- 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
- B60J: WINDOWS, WINDSCREENS, NON-FIXED ROOFS, DOORS, OR SIMILAR DEVICES FOR VEHICLES; REMOVABLE EXTERNAL PROTECTIVE COVERINGS SPECIALLY ADAPTED FOR VEHICLES (fastening, suspending, closing, or opening of such devices E05)

## Abstract

A light control sheet including a light control layer sandwiched between first and second orientation layers and including a polymer network in which domains are dispersed and filled with a liquid crystal composition including a liquid crystal molecule and a dichroic dye, a pair of transparent electrodes sandwiching the orientation layers, and a polarizing layer positioned on an opposite side of the first orientation layer to the light control layer. The light control layer has a transmittance that increases upon application of a driving voltage to the pair of transparent electrodes. When the driving voltage is not applied between the transparent electrodes, the orientation layers orient the liquid crystal molecule and the dichroic dye horizontally to the orientation layers and orient an orient absorption ax of the dichroic dye to cross an absorption axis of the polarizing layer as viewed in a thickness direction of the light control layer.

## Claims

### Claim 1

A light control sheet, comprising:
a pair of orientation layers including a first orientation layer and a second orientation layer;
a pair of transparent electrodes sandwiching the pair of orientation layers and comprising a first transparent electrode formed on the first orientation layer and a second transparent electrode formed on the second orientation layer;
a light control layer sandwiched between the first and second orientation layers and configured to increase transmittance upon application of driving voltage to the pair of transparent electrodes; and
a polarizing layer positioned on the first orientation layer of the pair of orientation layers on an opposite side with respect to the light control layer,
wherein the light control layer includes a polymer network and a liquid crystal composition forming a plurality of domains in the polymer network such that the plurality of domains are connected each other through adjacent ones of the domains and have an average domain diameter of 0.1 μM or more, that the liquid crystal composition is continuous through the plurality of domains and that at least one of the domains is in contact with at least one of the first and second orientation layers, and the liquid crystal composition includes a plurality of liquid crystal molecules and a dichroic dye such that when the driving voltage is not applied between the pair of transparent electrodes, the pair of orientation layers orient the liquid crystal molecule and the dichroic dye horizontally to the pair of orientation layers and orient an absorption axis of the dichroic dye to cross an absorption axis of the polarizing layer with respect to a thickness direction of the light control layer.

### Claim 2 (depends on 1)

The light control sheet according to claim 1, wherein the liquid crystal molecule has an extraordinary refractive index greater than an ordinary refractive index such that a difference between the extraordinary refractive index and the ordinary refractive index is greater than a difference between the ordinary refractive index of the liquid crystal molecules and a refractive index of the polymer network.

### Claim 3 (depends on 2)

The light control sheet according to claim 2, wherein the refractive index of the polymer network is equal to the ordinary refractive index of the liquid crystal molecule.

### Claim 4 (depends on 3)

The light control sheet according to claim 3, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, the polarizing layer includes a polarizer and a pair of transparent films sandwiching the polarizer, the pair of transparent films include a first transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate and a second transparent film positioned between the polarizer and the first transparent substrate, and the second transparent film has a thickness smaller than a thickness of the first transparent film.

### Claim 5 (depends on 4)

The light control sheet according to claim 4, wherein the pair of transparent electrodes include a first transparent electrode sandwiched between the first orientation layer and the polarizing layer and a second transparent electrode positioned on the second orientation layer on an opposite side with respect to the light control layer, the pair of transparent substrates include the first transparent substrate and the second transparent substrate, and the light control sheet further comprises at least one of a first hard coat layer positioned on the polarizing layer on the opposite side with respect to the first transparent substrate and a second hard coat layer positioned on the second transparent substrate on an opposite side with respect to the second transparent electrode.

### Claim 6 (depends on 3)

The light control sheet according to claim 3, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, and the polarizing layer includes a polarizer contacting the first transparent substrate and a transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate, and contacting the polarizer.

### Claim 7 (depends on 6)

The light control sheet according to claim 6, wherein the pair of transparent electrodes include a first transparent electrode sandwiched between the first orientation layer and the polarizing layer and a second transparent electrode positioned on the second orientation layer on an opposite side with respect to the light control layer, the pair of transparent substrates include the first transparent substrate and the second transparent substrate, and the light control sheet further comprises at least one of a first hard coat layer positioned on the polarizing layer on the opposite side with respect to the first transparent substrate and a second hard coat layer positioned on the second transparent substrate on an opposite side with respect to the second transparent electrode.

### Claim 8 (depends on 2)

The light control sheet according to claim 2, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, the polarizing layer includes a polarizer and a pair of transparent films sandwiching the polarizer, the pair of transparent films include a first transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate and a second transparent film positioned between the polarizer and the first transparent substrate, and the second transparent film has a thickness smaller than a thickness of the first transparent film.

### Claim 9 (depends on 2)

The light control sheet according to claim 2, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, and the polarizing layer includes a polarizer contacting the first transparent substrate and a transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate and contacting the polarizer.

### Claim 10 (depends on 1)

The light control sheet according to claim 1, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, the polarizing layer includes a polarizer and a pair of transparent films sandwiching the polarizer, the pair of transparent films include a first transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate and a second transparent film positioned between the polarizer and the first transparent substrate, and the second transparent film has a thickness smaller than a thickness of the first transparent film.

### Claim 11 (depends on 10)

The light control sheet according to claim 10, wherein the pair of transparent electrodes include a first transparent electrode sandwiched between the first orientation layer and the polarizing layer and a second transparent electrode positioned on the second orientation layer on an opposite side with respect to the light control layer, the pair of transparent substrates include the first transparent substrate and the second transparent substrate, and the light control sheet further comprises at least one of a first hard coat layer positioned on the polarizing layer on the opposite side with respect to the first transparent substrate and a second hard coat layer positioned on the second transparent substrate on an opposite side with respect to the second transparent electrode.

### Claim 12 (depends on 1)

The light control sheet according to claim 1, further comprising:
a pair of transparent substrates sandwiching the pair of transparent electrodes,
wherein the pair of transparent substrates include a first transparent substrate and a second transparent substrate such that the first transparent substrate is positioned between the first orientation layer and the polarizing layer, and the polarizing layer includes a polarizer contacting the first transparent substrate and a transparent film positioned on the polarizer on an opposite side with respect to the first transparent substrate, and contacting the polarizer.

### Claim 13 (depends on 12)

The light control sheet according to claim 12, wherein the pair of transparent electrodes include a first transparent electrode sandwiched between the first orientation layer and the polarizing layer and a second transparent electrode positioned on the second orientation layer on an opposite side with respect to the light control layer, the pair of transparent substrates include the first transparent substrate and the second transparent substrate, and the light control sheet further comprises at least one of a first hard coat layer positioned on the polarizing layer on the opposite side with respect to the first transparent substrate and a second hard coat layer positioned on the second transparent substrate on an opposite side with respect to the second transparent electrode.

### Claim 14 (depends on 1)

A light control window, comprising:
a transmission section that transmits light;
a frame body surrounding the transmission section; and
the light control sheet of claim 1,
wherein the light control sheet is positioned in the transmission section.

### Claim 15 (depends on 14)

The light control window according to claim 14, wherein the transmission section includes at least one plate member having optical transparency, the plate member includes an inner surface configured to be positioned to face inside of a vehicle passenger compartment and an outer surface configured to be positioned to face outside of the vehicle passenger compartment, and the light control sheet is positioned on the inner surface such that the polarizing layer is sandwiched between the plate member and the light control layer.

### Claim 16 (depends on 15)

The light control window according to claim 15, wherein the polarizing layer has a thickness in a range of 25 μm to 120 μm.

### Claim 17 (depends on 14)

The light control window according to claim 14, wherein the at least one plate member comprises two plate members having optical transparency, and the light control sheet is sandwiched between the two plate members.

### Claim 18 (depends on 17)

The light control window according to claim 17, wherein the polarizing layer has a thickness in a range of 25 μm to 120 μm.

### Claim 19 (depends on 1)

The light control sheet according to claim 1, wherein the light control layer is formed such that the liquid crystal composition is in a form of the plurality of domains having an average domain diameter in a range of 0.1 μm to 5 μm.

### Claim 20 (depends on 1)

The light control sheet according to claim 1, wherein the light control layer is formed such that the liquid crystal composition is in a form of the plurality of domains having an average domain diameter in a range of 0.2 μm to 3 μm.