# US 12,216,373 B2 · Vehicle display device comprising first and second viewing angle control panels and a polarization axis rotation element between the first viewing angle control panel and a display panel

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- Number: US 12,216,373 B2
- Document ID: US12216373B2
- Status: Granted
- Kind: B2
- Application number: 18/630,538
- Filed: 2024-04-09
- Published: 2024-08-15
- Granted: 2025-02-04
- Earliest claimed: 2020-03-25
- Assignees: Japan Display Inc.
- Applicants: Japan Display Inc.
- Inventors: Toshiharu Matsushima
- Web page: https://patentgrep.com/patent/US12216373B2

## 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
- B60K 35/22: Display screens
- B60K 35/60: Instruments characterised by their location or relative disposition in or on vehicles (arrangements of lighting devices on dashboards B60Q3/10)
- B60K 35/81: for controlling displays
- G02F 1/0136: {for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation (G02F1/0353 takes precedence)}
- G02F 1/133531: {characterised by the arrangement of polariser or analyser axes}
- G02F 1/133638: {Waveplates, i.e. plates with a retardation value of lambda/n}
- G02F 1/1347: Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
- G02F 1/13471: {in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence)}
- G02F 1/1396: {the liquid crystal being selectively controlled between a twisted state and a non-twisted state, e.g. TN-LC cell (G02F1/141 takes precedence)}
- G09F 9/00: Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements (in which the variable information is permanently attached to a movable support G09F11/00; abacus G06C1/00; slide-rules G06G1/00)
- B60K 2360/1526: Dual-view displays
- B60K 2360/25: using filters
- B60K 2360/33: Illumination features
- B60K 2360/343: Illumination of matrix displays
- 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
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS

## Abstract

According to one embodiment, a display device includes a display panel configured to modulate a first polarization component, a first viewing angle control panel including a first liquid crystal layer containing twisted liquid crystal molecules, a second viewing angle control panel including a second liquid crystal layer containing twisted liquid crystal molecules, and a polarization axis rotation element provided between the first viewing angle control panel and the display panel. A second polarization axis of a second polarization component which passed through the first viewing angle control panel is different from a first polarization axis of the first polarization component. The polarization axis rotation element is configured to rotate the second polarization axis.

## Claims

### Claim 1

A vehicle display device provided in a vehicle, comprising:
a display panel configured to modulate a first polarization component;
a first viewing angle control panel comprising a first liquid crystal layer containing twisted liquid crystal molecules;
a second viewing angle control panel comprising a second liquid crystal layer containing twisted liquid crystal molecules;
a polarization axis rotation element provided between the first viewing angle control panel and the display panel;
a first polarizer provided on a front side of the display panel;
a second polarizer provided between the display panel and the polarization axis rotation element; and
a third polarizer provided between the polarization axis rotation element and the first viewing angle control panel, wherein
the first viewing angle control panel is provided between the second viewing angle control panel and the polarization axis rotation element,
a driver seat and a passenger seat are arranged in a first direction,
an alignment state of the first liquid crystal layer is different from an alignment state of the second liquid crystal layer,
at least one of a long axis of the liquid crystal molecule located in an intermediate layer of the first liquid crystal layer and a long axis of the liquid crystal molecule located in an intermediate layer of the second liquid crystal layer is aligned in the first direction,
a second polarization axis of a second polarization component which passed through the first viewing angle control panel is different from a first polarization axis of the first polarization component,
the polarization axis rotation element is configured to rotate the second polarization axis,
the second polarizer comprises a second transmission axis which transmits the first polarization component,
the third polarizer comprises a third transmission axis which transmits the second polarization component, and
a fast axis or slow axis of the polarization axis rotation element is located in an intermediate direction between a direction of the second transmission axis and a direction of the third transmission axis.

### Claim 2 (depends on 1)

The vehicle display device of claim 1, wherein
the polarization axis rotation element is configured to impart a half-wave retardation to the second polarization component.

### Claim 3 (depends on 1)

The vehicle display device of claim 1, wherein
an alignment direction of the liquid crystal molecule located in the intermediate layer of the first liquid crystal layer is substantially orthogonal to an alignment direction of the liquid crystal molecule located in the intermediate layer of the second liquid crystal layer.

### Claim 4 (depends on 1)

The vehicle display device of claim 1, wherein
an alignment direction of the liquid crystal molecule located in the intermediate layer of the first liquid crystal layer is substantially parallel to an alignment direction of the liquid crystal molecule located in the intermediate layer of the second liquid crystal layer.

### Claim 5

A vehicle comprising:
a windshield provided in a front part of the vehicle;
a driver seat and a passenger seat;
a dashboard provided in front of the driver seat and the passenger seat; and
a display device provided in the dashboard, wherein
the display device comprises:
a display panel;
a polarization axis rotation element;
a first viewing angle control panel configured such that a transmittance on a driver seat side is less than a transmittance on a passenger seat side;
a second viewing angle control panel configured such that a transmittance on a windshield side is less than a transmittance on an opposite side;
a first polarizer provided on a front side of the display panel;
a second polarizer provided between the display panel and the polarization axis rotation element; and
a third polarizer provided between the polarization axis rotation element and the first viewing angle control panel,
the polarization axis rotation element is provided between the first viewing angle control panel and the display panel,
the display panel is configured to modulate a first polarization component,
a second polarization axis of a second polarization component which passed through the first viewing angle control panel is different from a first polarization axis of the first polarization component,
the second polarizer comprises a second transmission axis which transmits the first polarization component,
the third polarizer comprises a third transmission axis which transmits the second polarization component, and
a fast axis or slow axis of the polarization axis rotation element is located in an intermediate direction between a direction of the second transmission axis and a direction of the third transmission axis.

### Claim 6 (depends on 5)

The vehicle of claim 5, wherein
the display device further comprises an illumination device,
the first viewing angle control panel and the second viewing angle control panel are provided between the illumination device and the polarization axis rotation element,
the first viewing angle control panel comprises a first liquid crystal layer containing a twisted liquid crystal molecule,
the second viewing angle control panel comprises a second liquid crystal layer containing a twisted liquid crystal molecule,
an alignment state of the first liquid crystal layer is different from an alignment state of the second liquid crystal layer, and
the polarization axis rotation element is configured to rotate the second polarization axis.