Patents by Inventor Hoi Wai Choi

Hoi Wai Choi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11688833
    Abstract: A nanostructure fabricated on a semiconductor light-emitting device induces strain in the active region. The active device includes at least one quantum heterostructure, in which the strain changes the extent of Quantum Confined Stark Effect, and thus modifies the wavelength of light emission. By mixing strain relaxation and strain induction effects there is a spectral broadening of the light emission, providing polychromatic light emission.
    Type: Grant
    Filed: May 17, 2021
    Date of Patent: June 27, 2023
    Assignee: VERSITECH LIMITED
    Inventors: Hoi Wai Choi, Wai Yuen Fu
  • Publication number: 20210273140
    Abstract: A nanostructure fabricated on a semiconductor light-emitting device induces strain in the active region. The active device includes at least one quantum heterostructure, in which the strain changes the extent of Quantum Confined Stark Effect, and thus modifies the wavelength of light emission. By mixing strain relaxation and strain induction effects there is a spectral broadening of the light emission, providing polychromatic light emission.
    Type: Application
    Filed: May 17, 2021
    Publication date: September 2, 2021
    Applicant: VERSITECH LIMITED
    Inventors: Hoi Wai CHOI, Wai Yuen FU
  • Patent number: 11094855
    Abstract: A nanostructure fabricated on a semiconductor light-emitting device induces strain in the active region. The active device includes at least one quantum heterostructure, in which the strain changes the extent of Quantum Confined Stark Effect, and thus modifies the wavelength of light emission. By mixing strain relaxation and strain induction effects there is a spectral broadening of the light emission, providing polychromatic light emission.
    Type: Grant
    Filed: March 12, 2018
    Date of Patent: August 17, 2021
    Assignee: Versitech Limited
    Inventors: Hoi Wai Choi, Wai Yuen Fu
  • Publication number: 20200135982
    Abstract: A nanostructure fabricated on a semiconductor light-emitting device induces strain in the active region. The active device includes at least one quantum heterostructure, in which the strain changes the extent of Quantum Confined Stark Effect, and thus modifies the wavelength of light emission. By mixing strain relaxation and strain induction effects there is a spectral broadening of the light emission, providing polychromatic light emission.
    Type: Application
    Filed: March 12, 2018
    Publication date: April 30, 2020
    Applicant: Versitech Limited
    Inventors: Hoi Wai CHOI, Wai Yuen FU
  • Patent number: 10615222
    Abstract: Methods of fabricating flexible, free-standing LED structures are provided. An LED structure can be formed on a sapphire substrate, and the surface of the LED structure can then be coated with epoxy and attached to a rigid supporting substrate. A laser lift-off process can be performed using an ultraviolent beam from a high-power pulsed-mode laser and a shadow mask, causing at least a portion of the LED structure to separate from the sapphire substrate. The structure can then be immersed in an acetone bath to dissolve the epoxy and separate the structure from the supporting substrate.
    Type: Grant
    Filed: August 20, 2015
    Date of Patent: April 7, 2020
    Assignee: The University of Hong Kong
    Inventors: Hoi Wai Choi, Kwai Hei Li, Yuk Fai Cheung
  • Publication number: 20190157508
    Abstract: A device includes a light-emitting diode (LED) integrated with a photodetector on the same semiconductor platform, such that the photocurrent generated by the photodetector can be used to monitor the optical output of the LED, which is located adjacent to the photodetector. The device provides a compact, robust, reliable and low-cost way of monitoring LED emission.
    Type: Application
    Filed: May 17, 2016
    Publication date: May 23, 2019
    Applicant: The University of Hong Kong
    Inventors: Hoi Wai CHOI, Kwai Hei LI, Haitao LU
  • Publication number: 20160233269
    Abstract: Methods of fabricating flexible, free-standing LED structures are provided. An LED structure can be formed on a sapphire substrate, and the surface of the LED structure can then be coated with epoxy and attached to a rigid supporting substrate. A laser lift-off process can be performed using an ultraviolent beam from a high-power pulsed-mode laser and a shadow mask, causing at least a portion of the LED structure to separate from the sapphire substrate. The structure can then be immersed in an acetone bath to dissolve the epoxy and separate the structure from the supporting substrate.
    Type: Application
    Filed: August 20, 2015
    Publication date: August 11, 2016
    Inventors: Hoi Wai Choi, Kwai Hei Li, Yuk Fai Cheung
  • Patent number: 9401453
    Abstract: A nano-LED containing an array of nano-pillars of different diameters that are distributed over an emission area of an LED chip is capable of emitting broadband and white or nearly white light. Since each pillar emits light at a different wavelength according to its diameter and strain state, the overall emission spectral characteristics of the device is a combination of individual spectrum, giving rise to broadband emission. The spectral shape can be tailored for different shades of white emission, by controlling the distribution of the different diameter nano-pillars. The nano-pillars are patterned by nanosphere lithography.
    Type: Grant
    Filed: May 24, 2013
    Date of Patent: July 26, 2016
    Assignee: THE UNIVERSITY OF HONG KONG
    Inventor: Hoi Wai Choi
  • Publication number: 20130313517
    Abstract: A nano-LED containing an array of nano-pillars of different diameters that are distributed over an emission area of an LED chip is capable of emitting broadband and white or nearly white light. Since each pillar emits light at a different wavelength according to its diameter and strain state, the overall emission spectral characteristics of the device is a combination of individual spectrum, giving rise to broadband emission. The spectral shape can be tailored for different shades of white emission, by controlling the distribution of the different diameter nano-pillars. The nano-pillars are patterned by nanosphere lithography.
    Type: Application
    Filed: May 24, 2013
    Publication date: November 28, 2013
    Applicant: THE UNIVERSITY OF HONG KONG
    Inventor: Hoi Wai Choi
  • Publication number: 20120292788
    Abstract: Methods and systems are provided to utilize and manufacture a stacked chip assembly. Microelectronic or optoelectronic chips of any dimensions are directly stacked onto each other. The chips can be of substantially identical sizes. To enable forming the stacked chip assembly, trenches are laser micro-machined onto the bottom surface of a chip to accommodate the bond wedge/ball and wire path of the chip beneath it. Consequently, chips can be tightly integrated without a gap and without having to reserve space for the bond wedges/balls.
    Type: Application
    Filed: May 18, 2012
    Publication date: November 22, 2012
    Applicant: The University of Hong Kong
    Inventor: Hoi Wai Choi
  • Patent number: 7982228
    Abstract: Methods and systems are provided that may be used to utilize and manufacture a light sources apparatus. A first light emitting diode emits light having a first wavelength, and a second light emitting diode for emitting light having a second wavelength. Each of the first and second light emitting diodes may comprise angled facets to reflect incident light in a direct toward a top end of the first light emitting diode. The second light emitting diode comprising angled facets may reflect incident light in a direction toward a top end of the second light emitting diode. A first distributed Bragg reflector is disposed between the top end of the first light emitting diode and a bottom end of the second light emitting diode to allow light from the first light emitting diode to pass through and to reflect light from the second light emitting diode.
    Type: Grant
    Filed: October 2, 2009
    Date of Patent: July 19, 2011
    Assignee: Versitech Limited
    Inventors: Hoi Wai Choi, Kwun Nam Hui, Xianghua Wang
  • Publication number: 20100084668
    Abstract: Methods and systems are provided that may be used to utilize and manufacture a light sources apparatus. A first light emitting diode emits light having a first wavelength, and a second light emitting diode for emitting light having a second wavelength. Each of the first and second light emitting diodes may comprise angled facets to reflect incident light in a direct toward a top end of the first light emitting diode. The second light emitting diode comprising angled facets may reflect incident light in a direction toward a top end of the second light emitting diode. A first distributed Bragg reflector is disposed between the top end of the first light emitting diode and a bottom end of the second light emitting diode to allow light from the first light emitting diode to pass through and to reflect light from the second light emitting diode.
    Type: Application
    Filed: October 2, 2009
    Publication date: April 8, 2010
    Inventors: Hoi Wai CHOI, Kwun Nam HUI, Xianghua WANG
  • Patent number: 7598149
    Abstract: An array of light emitting devices, each device comprising a sloped wall mesa (24) of luminescent semiconductor material. Extending over the sloped wall mesas (24) is a metal contact (30). The array can be arranged as a parallel addressable system so that all devices (24) can be stimulated to emit light simultaneously. Alternatively, the array can be arranged as a matrix addressable array, in which case individual devices can be selectively stimulated.
    Type: Grant
    Filed: February 2, 2004
    Date of Patent: October 6, 2009
    Assignee: University of Strathclyde
    Inventors: Martin David Dawson, Hoi Wai Choi, Chan-Wook Jeon
  • Publication number: 20080043798
    Abstract: A vertical-cavity device comprises: (a) a chip comprising an active semiconductor layer for providing optical gain; (b) a first mirror arranged on a first side of the active layer; (c) a second mirror arranged on a second side of the active layer, opposite to the first mirror, and forming with at least the first mirror an optically resonant cavity that passes through the active layer in a direction out of the plane of the active layer; (d) a heatspreader for removing heat from the active layer, the heatspreader being arranged inside the cavity and having a first surface adjacent to the chip and a second surface opposite to the first surface, the heatspreader being transparent to light of wavelengths in an operating bandwidth of the device. In addition to removing heat from the active layer, the heatspreader also has one or more further selected property that has a further selected effect on light output from the device.
    Type: Application
    Filed: March 24, 2004
    Publication date: February 21, 2008
    Applicant: The University of Strathclyde
    Inventors: Stephane Luc Dominique Calvez, John-Mark Hopkins, David Burns, Martin David Dawson, Chan Wook Jeon, Hoi Wai Choi
  • Publication number: 20080023715
    Abstract: A light emitting diode comprising of a fluorescent microsphere coating is proposed. The coating consists of fluorescent microspheres which fluoresce at green and red wavelengths, excited by a shorter wavelength LED. Due to the micron-scale dimension of the spheres, they are non-resolvable to the human eye and the overall optical output appears as color mixed. By varying the proportions of green and red fluorescent microspheres and the wavelength of the excitation source, the color of the optical output can be tuned. If the optical output has of blue, green and red components in the correct proportions, white color emission can be achieved. The light emitting diode can be sectioned into multiple individually-addressable regions. Each section can emit at a different wavelength according to the type of fluorescent microspheres coated. By varying the intensity of the blue, green and red regions by changing the bias voltage, the output wavelength (color) can be continuously tuned (varied).
    Type: Application
    Filed: July 19, 2007
    Publication date: January 31, 2008
    Inventor: Hoi Wai CHOI