Light emitting devices featuring optical mode enhancement

• US 10,559,630 B2
• Filed: 12/21/2017
• Issued: 02/11/2020
• Est. Priority Date: 12/21/2017
• Status: Expired due to Fees

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Schubert, Martin Friedrich, Grundmann, Michael Jason, Apte, Raj B., Schillings, Benoit
• Primary Examiner(s): Hoang, Quoc D
• Application Number:
  US15/850,959
• Publication Number:
  US 20190198576A1
• Time in Patent Office: 782 Days
• CPC Class Codes: G02B 1/005 made of photonic crystals or photonic band gap materials photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295
• CPC Class Codes: G02B 17/004 Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators multipass arrangements for optical cuvettes G01N21/031; laser resonators H01S3/05
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 26/004 based on a displacement or a deformation of a fluid
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G02B 26/0875 by means of one or more refracting elements
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: G02B 30/34 Stereoscopes providing a stereoscopic pair of separated images corresponding to parallactically displaced views of the same object, e.g. 3D slide viewers
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 33/105 with a resonant cavity structure
• CPC Class Codes: H01L 33/28 containing only elements of Group II and Group VI of the Periodic Table
• CPC Class Codes: H01L 33/30 containing only elements of Group III and Group V of the Periodic Table
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/465 with a resonant cavity structure
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 : Reflective elements
• CPC Class Codes: H04N 13/32 : using arrays of controllable light sources; using moving apertures or moving light sources
• CPC Class Codes: H04N 13/322 : using varifocal lenses or mirrors
• CPC Class Codes: H04N 13/324 : Colour aspects
• CPC Class Codes: H04N 13/351 : for displaying simultaneously
• CPC Class Codes: H04N 13/398 : Synchronisation thereof; Control thereof
• CPC Class Codes: H10K 19/20 : comprising components having an active region that includes an inorganic semiconductor
• CPC Class Codes: H10K 50/818 : Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 50/82 : Cathodes
• CPC Class Codes: H10K 50/85 : Arrangements for extracting light from the devices
• CPC Class Codes: H10K 50/852 : comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 50/856 : comprising reflective means
• CPC Class Codes: H10K 50/858 : comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 59/35 : comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 59/80518 : Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 59/876 : comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/878 : comprising reflective means
• CPC Class Codes: H10K 59/879 : comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 77/10 : Substrates, e.g. flexible substrates
• CPC Class Codes: H10K 85/114 : Poly-phenylenevinylene; Derivatives thereof
• CPC Class Codes: Y02E 10/549 : Organic PV cells

Abstract

A light emitting device includes a substrate supporting a first light emitting element and a second light emitting element, the first light emitting element being configured to emit, in a first principal direction, light in a first wavelength band and the second light emitting element being configured to emit, in the first principal direction, light in a second wavelength band different from the first wavelength band, each light emitting element including: a light emitting diode layer, extending in a plane perpendicular to the first direction, having a thickness of 10 microns or less in the first direction and a maximum lateral dimension of 100 microns or less orthogonal to the first direction, the light emitting diode layer including a semiconductor material; and one or more layers configured to enhance an optical mode of the light emitted in the corresponding first or second wavelength band perpendicular to the plane and/or suppress an optical mode of the light emitted in the corresponding first or second wavelength band in the plane.

Claims

1. A light emitting device, comprising:

a substrate supporting a first light emitting element and a second light emitting element, the first light emitting element being configured to emit, in a first principal direction, light in a first wavelength band and the second light emitting element being configured to emit, in the first principal direction, light in a second wavelength band different from the first wavelength band, each light emitting element comprising;

a light emitting diode layer, extending in a plane perpendicular to the first principal direction, having a thickness of 10 microns or less in the first principal direction and a maximum lateral dimension of 100 microns or less orthogonal to the first principal direction, the light emitting diode layer comprising a semiconductor material; and

one or more layers configured to enhance an optical mode of the light emitted in the corresponding first or second wavelength band perpendicular to the plane and/or suppress an optical mode of the light emitted in the corresponding first or second wavelength band in the plane,

wherein, for at least one of the light emitting elements, the one or more layers comprise at least two layers positioned on opposite sides of the diode layer,

and wherein the at least two layers form a resonant optical cavity configured to enhance the optical mode of the light emitted in the corresponding one of the first or second wavelength bands perpendicular to the plane and the two layers are reflective at the corresponding one of the first and second emitted wavelengths.

2. The light emitting device of claim 1, wherein the light emitting diode layer of each light emitting element comprises an active layer, a hole transport layer, and an electron transport layer.

3. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, at least one of the reflective layers comprises a Distributed Bragg Reflector.

4. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, at least one of the reflective layers provides an electrically-conductive contact.

5. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, one of the two layers is partially transmissive at the corresponding one of the first and second emitted wavelengths.

6. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, the one or more layers comprise a photonic crystal layer positioned adjacent to the diode layer,

wherein the photonic crystal layer comprises a two dimensional photonic crystal structure that is configured to suppress the optical mode of the light emitted in the corresponding one of the first and second wavelength bands in the plane.

7. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, the light emitting diode layer has a thickness of 10 μ

m or less in the first direction.

8. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, the light emitting diode layer has a maximum lateral dimension of 50 μ

m or less orthogonal to the first principal direction.

9. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, the light emitting diode layer comprises an inorganic crystalline semiconductor material.

10. The light emitting device of claim 9, wherein the inorganic crystalline semiconductor material is a III-V semiconductor material or a II-VI semiconductor material.

11. The light emitting device of claim 1, wherein, for at least one of the light emitting elements, the light emitting diode layer comprises an organic semiconductor material.

12. The light emitting device of claim 11, wherein the organic semiconductor material comprises poly(p-phenylene vinylene).

13. The light emitting device of claim 1, wherein the first and/or second wavelength band comprise visible light.

14. The light emitting device of claim 1, wherein the first and/or second light emitting element is configured to emit light in a corresponding first principal direction with a divergence angle 15°

or less.