Electronic Device Display With Switchable Film Structures

Patent metadata

Field	Value
Publication number	US-2016357046-A1
Application number	US-201615064097-A
Country	US
Kind code	A1
Filing date	Mar 8, 2016
Priority date	Jun 3, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

An electronic device may generate content that is to be displayed on a display. The display may have an array of liquid crystal display pixels for displaying image frames of the content. The display may be operated in at least a normal viewing mode, a privacy mode, an outdoor viewing mode, and a power saving mode. The different view modes may exhibit different viewing angles. In one configuration, the display may include a switchable phase retarder that can be selectively activated to help reduce contrast ratios at higher viewing angles. A rotated pixel design that includes one or more groups of parallel fingers can be used to help properly align the low contrast regions. In another configuration, the display may include multiple electrically controlled birefringence (ECB) layers that can be selectively activated to provide a desired cone of vision, a region outside of which exhibits substantially reduced contrast ratios.

First claim

What is claimed is:

1 . An electronic device display, comprising:
display layers having thin-film transistor structures; and a switchable phase retarder that is configured in an isotropic state when the electronic device display is operated in a normal viewing mode and that is configured in an anisotropic state when the electronic device display is operated in a privacy mode.

2 . The electronic device display of claim 1 , further comprising:
an upper polarizer; and a lower polarizer, wherein the switchable phase retarder is interposed between the upper polarizer and the display layers.

3 . The electronic device display of claim 1 , further comprising:
an upper polarizer; and a lower polarizer, wherein the switchable phase retarder is interposed between the lower polarizer and the display layers.

4 . The electronic device display of claim 1 , wherein the switchable phase retarder comprises blue phase liquid crystal material.

5 . The electronic device display of claim 1 , wherein the switchable phase retarder provides reduced contrast ratios at viewing angles greater than 30° during the privacy mode.

6 . The electronic device display of claim 1 , wherein the switchable phase retarder receives a bias voltage during the privacy mode such that the switchable phase retarder is configured to provide a predetermined amount of phase retardation.

7 . The electronic device display of claim 1 , wherein the display layers comprises:
parallel pixel finger electrodes angled at less than 75°.

8 . The electronic device display of claim 1 , wherein the display layers comprises:
parallel pixel finger electrodes angled at less than 60°.

9 . The electronic device display of claim 8 , wherein the parallel pixel finger electrodes are shorted using a conductive vertical sidebar.

10 . The electronic device display of claim 8 , wherein the parallel pixel finger electrodes are shorted using a conductive crossbar that is substantially perpendicular to the pixel finger electrodes.

11 . The electronic device display of claim 10 , wherein the conductive crossbar and the parallel pixel finger electrodes have different widths.

12 . The electronic device display of claim 1 , wherein the display layers further comprises:
a first set of parallel pixel electrode fingers formed at a first angle; a second set of parallel pixel electrode fingers formed at a second angle that is different than the first angle; and a conductive crossbar that shorts the first and second sets of parallel pixel electrode fingers.

13 . Display circuitry, comprising:
a front polarizer; a back polarizer; a liquid crystal display (LCD) layer; and a first electrically controlled birefringence (ECB) layer that is selectively activated to place the display circuitry in a privacy mode and deactivated to place the display circuitry in a normal viewing mode.

14 . The display circuitry of claim 13 , further comprising:
a second electrically controlled birefringence (ECB) layer that is selectively activated to place the display circuitry in the privacy mode and deactivated to place the display circuitry in the normal viewing mode.

15 . The display circuitry of claim 14 , wherein:
the front polarizer exhibits a first absorption axis; the back polarizer exhibits a second absorption axis that is orthogonal to the first absorption axis; during the normal viewing mode, the first ECB layer exhibits an optical axis that is parallel to the first absorption axis; during the normal view mode, the second ECB layer exhibits an optical axis that is parallel to the second absorption axis.

16 . The display circuitry of claim 15 , wherein:
during the privacy mode, the optical axis of the first ECB layer is adjusted to be out of alignment from the first absorption axis; and during the privacy mode, the optical axis of the second ECB layer is adjusted to be out of alignment from the second absorption axis.

17 . The display circuitry of claim 14 , wherein the first and second ECB layers provide a uniform cone of vision during the privacy mode, and wherein the contrast ratio is substantially reduced outside the cone of vision.

18 . The display circuitry of claim 14 , wherein the first and second ECB layers are interposed between the LCD layer and the back polarizer.

19 . The display circuitry of claim 14 , wherein the first and second ECB layers are interposed between the LCD layer and the front polarizer.

20 . The display circuitry of claim 14 , wherein the first ECB layer is interposed between the LCD layer and the front polarizer, and wherein the second ECB layer is interposed between the LCD layer and the back polarizer.

Assignees

• Apple Inc

Inventors

• Choi Hyungryul J
• Jiang Shih-Chyuan Fan
• Carbone Giovanni

Classifications

• G02F2203/50

  Phase-only modulation · CPC title

• G02F1/133528

  Polarisers · CPC title

• G09G2320/068

  for control of viewing angle adjustment · CPC title

• G02F1/1393 Primary

  the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells (G02F1/1396, G02F1/141 take precedence) · CPC title

• G02B6/005 Primary

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title