Displays having polarizing structures formed using narrowband dichroic dyes

• US 9,685,635 B2
• Filed: 10/12/2015
• Issued: 06/20/2017
• Est. Priority Date: 01/05/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Drolet, Jean-Jacques P.
• Primary Examiner(s): Schoenholtz, Joseph
• Application Number:
  US14/881,072
• Publication Number:
  US 20160197309A1
• Time in Patent Office: 617 Days
• Field of Search: None
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

A display may have thin-film transistor circuitry on a substrate. An array of organic light-emitting diodes may be formed on the thin-film transistor circuitry. The organic light-emitting diodes may have anodes, cathodes, and emissive material located between the anodes and cathodes. A circular polarizer may be formed over the array of organic light-emitting diodes. The circular polarizer may include a linear polarizer and a quarter wave plate. The linear polarizer may be formed from one or more film layers having narrowband dichroic dyes so that the polarizer exhibits transmission peaks aligned with a selected subset of wavelengths and absorbance notches corresponding to the selected subset of wavelengths. The selected subset of wavelengths may cover the ranges where the light-emitting diodes are outputting light. Configured in this way, the polarizer will exhibit enhanced luminance at the desired wavelengths while suppressing ambient light reflections at other wavelengths in the visible spectrum.

Claims

1. A display, comprising:

a substrate;

a pixel that is formed on the substrate and that emits light at a given wavelength; and

a circular polarizer that is formed over the pixel and that exhibits a transmission profile for light passing through the circular polarizer from the pixel, wherein the transmission profile has at least one peak at the given wavelength, and wherein the circular polarizer comprises narrowband dichroic dyes that allow light at the given wavelength to pass through the circular polarizer while blocking light at other wavelengths.

2. The display defined in claim 1, wherein the circular polarizer comprises:

a linear polarizer; and

a quarter wave plate.

3. The display defined in claim 2, further comprising:

a first additional pixel that is formed on the substrate and that emits light at a first wavelength that is different than the given wavelength, wherein the transmission profile of the circular polarizer exhibits at least a first additional peak at the first wavelength.

4. The display defined in claim 3, further comprising:

a second additional pixel that is formed on the substrate and that emits light at a second wavelength that is different than the given wavelength and the first wavelength, wherein the transmission profile of the circular polarizer exhibits at least a second additional peak at the second wavelength.

5. The display defined in claim 2, wherein the linear polarizer is formed from the narrowband dichroic dyes.

6. The display defined in claim 5, wherein the linear polarizer is configured to exhibit an absorbance spectrum having at least one notch that is aligned to the given wavelength.

7. The display defined in claim 1, wherein the circular polarizer is configured such that the at least one peak provides at least a 10% luminance boost relative to transmission at other wavelengths.

8. The display defined in claim 1, wherein the circular polarizer is configured such that the at least one peak provides at least a 20% luminance boost relative to transmission at other wavelengths.

9. Display circuitry, comprising:

a pixel that produces light at a given wavelength; and

a circular polarizer formed over the pixel to suppress ambient light reflections, wherein the circular polarizer is formed from polarizing material having at least one absorption notch aligned to the given wavelength, and wherein the polarizing material comprises a narrowband dichroic dye that transmits light at the given wavelength while absorbing light having wavelengths outside of the absorption notch.

10. The display circuitry defined in claim 9, further comprising:

a first additional pixel that produces light at a first wavelength that is different than the given wavelength, wherein the polarizing material also exhibits low absorption values at the first wavelength.

11. The display circuitry defined in claim 10, further comprising:

a second additional pixel that produces light at a second wavelength that is different than the given wavelength and the first wavelength, wherein the polarizing material also exhibits low absorption values at the second wavelength.

12. The display circuitry defined in claim 11, wherein the given wavelength comprises the blue wavelength, wherein the first wavelength comprises the green wavelength, and wherein the second wavelength comprises the red wavelength.

13. The display circuitry defined in claim 12, wherein the circular polarizer suppresses ambient light reflections for all visible wavelengths except for light at the given, first, and second wavelengths.

14. The display circuitry defined in claim 9, wherein the pixel includes an organic light-emitting diode.