Patents by Inventor Gim Eng Chew

Gim Eng Chew 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).

  • Publication number: 20120006976
    Abstract: Disclosed are various embodiments of a single track reflective optical encoder featuring current amplifiers disposed in the signal generating circuit thereof. Voltage amplifiers and their associated feedback resistors are eliminated in the various embodiments disclosed herein, resulting in decreased die size and improved encoder signal accuracy and performance, especially at high speeds The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided. Methods of making and using such optical encoders are also disclosed.
    Type: Application
    Filed: July 7, 2010
    Publication date: January 12, 2012
    Applicant: Avago Technologies ECBU(Singapore) Pte, Ltd.
    Inventors: Chung Min Thor, Gim Eng Chew
  • Patent number: 8067992
    Abstract: Disclosed are various embodiments of temperature-compensated relaxation oscillator circuits that may be fabricated using conventional CMOS manufacturing techniques. The relaxation oscillator circuits described herein exhibit superior low temperature coefficient performance characteristics, and do not require the use of expensive off-chip high precision resistors to effect temperature compensation. Positive and negative temperature coefficient resistors arranged in a resistor array offset one another to provide temperature compensation in the relaxation oscillator circuit.
    Type: Grant
    Filed: June 6, 2008
    Date of Patent: November 29, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Alex Jianzhong Chen, Gim Eng Chew, Tong Tee Tan, Kok Chin Pan
  • Patent number: 8035074
    Abstract: Disclosed are various embodiments of pulse generation and automatic gain control (“AGC”) circuits and corresponding methods that are especially well suited for use in motion encoding systems. Analog output signals provided by a motion encoder serve as inputs to the pulse generation circuit, where peaks, valleys and/or crosspoints corresponding to such analog signals are first detected and then employed to generate output pulses corresponding thereto. These output pulses are next provided to an AGC circuit as self-generated clock signals which control the time windows over which the analog signals of the motion encoder are sampled and processed by the AGC circuit so as to adjust the gains applied to such analog signals.
    Type: Grant
    Filed: February 9, 2009
    Date of Patent: October 11, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Patent number: 7977623
    Abstract: According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.
    Type: Grant
    Filed: March 19, 2010
    Date of Patent: July 12, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Patent number: 7880657
    Abstract: Disclosed are various embodiments of interpolation circuits for use in conjunction with motion encoders. The analog output signals provided by incremental or absolute motion encoders are provided to an interpolation circuit, which is capable of providing high interpolation factor output signals having high timing accuracy. Problems with noise spikes common to zero-hysteresis comparators typically employed in interpolation circuits are eliminated, as are problems with time delays differing between comparators that do feature hysteresis. The disclosed interpolation circuits may be implemented using CMOS processes without undue effort.
    Type: Grant
    Filed: February 26, 2009
    Date of Patent: February 1, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Mei Yee Ng, Gim Eng Chew
  • Patent number: 7880658
    Abstract: Disclosed are various embodiments of interpolation circuits for use in conjunction with optical encoders. The analog output signals provided by incremental or absolute motion encoders are provided to an interpolation circuit, which is capable of providing high interpolation factor output signals having high timing accuracy. The disclosed interpolation circuits may be implemented using CMOS or BiCMOS processes without undue effort.
    Type: Grant
    Filed: July 31, 2009
    Date of Patent: February 1, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Kheng Hin Toh, Gim Eng Chew
  • Patent number: 7879641
    Abstract: A method for determining the light intensity of a light signal in each of a plurality of spectral bands is disclosed and a method for fabricating a photodetector is also disclosed.
    Type: Grant
    Filed: November 25, 2009
    Date of Patent: February 1, 2011
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Farn Hin Chen, Gim Eng Chew, Boon Keat Tan
  • Publication number: 20100301195
    Abstract: Disclosed are various embodiments of a single track reflective optical encoder featuring increased spatial resolution, reduced cross-talk between adjoining photodiodes, and increased amplitude output signals from individual photodiodes. With respect to prior art single track optical encoders, some photodiodes are removed from a photodiode array, while nevertheless maintaining appropriate phase relationships between pairs of A and A\, and B and B\, photodiodes. Such a configuration of photodiodes results in increased inter-photodiode spacing, and thereby permits spatial resolution to be increased while boosting current outputs from individual photodiodes. The single track optical encoder configurations disclosed herein permit very high resolution reflective optical encoders in small packages to be provided.
    Type: Application
    Filed: May 31, 2009
    Publication date: December 2, 2010
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Gim Eng Chew, Chee Wai Ng
  • Publication number: 20100302532
    Abstract: A method for determining the light intensity of a light signal in each of a plurality of spectral bands is disclosed and a method for fabricating a photodetector is also disclosed.
    Type: Application
    Filed: November 25, 2009
    Publication date: December 2, 2010
    Applicant: AVAGO TECHNOLOGIES ECBU IP (SINGAPORE) PTE. LTD.
    Inventors: Farn Hin Chen, Gim Eng Chew, Boon Keat Tan
  • Publication number: 20100252719
    Abstract: According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.
    Type: Application
    Filed: March 19, 2010
    Publication date: October 7, 2010
    Applicant: AVAGO TECHNOLOGIES ECBU (SINGAPORE) PTE. LTD.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Publication number: 20100213997
    Abstract: Disclosed are various embodiments of interpolation circuits for use in conjunction with motion encoders. The analog output signals provided by incremental or absolute motion encoders are provided to an interpolation circuit, which is capable of providing high interpolation factor output signals having high timing accuracy. Problems with noise spikes common to zero-hysteresis comparators typically employed in interpolation circuits are eliminated, as are problems with time delays differing between comparators that do feature hysteresis. The disclosed interpolation circuits may be implemented using CMOS processes without undue effort.
    Type: Application
    Filed: February 26, 2009
    Publication date: August 26, 2010
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd
    Inventors: Mei Yee Ng, Gim Eng Chew
  • Publication number: 20100214139
    Abstract: Disclosed are various embodiments of interpolation circuits for use in conjunction with optical encoders. The analog output signals provided by incremental or absolute motion encoders are provided to an interpolation circuit, which is capable of providing high interpolation factor output signals having high timing accuracy. The disclosed interpolation circuits may be implemented using CMOS or BiCMOS processes without undue effort.
    Type: Application
    Filed: July 31, 2009
    Publication date: August 26, 2010
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd.
    Inventors: Kheng Hin Toh, Gim Eng Chew
  • Publication number: 20100201422
    Abstract: Disclosed are various embodiments of pulse generation and automatic gain control (“AGC”) circuits and corresponding methods that are especially well suited for use in motion encoding systems. Analog output signals provided by a motion encoder serve as inputs to the pulse generation circuit, where peaks, valleys and/or crosspoints corresponding to such analog signals are first detected and then employed to generate output pulses corresponding thereto. These output pulses are next provided to an AGC circuit as self-generated clock signals which control the time windows over which the analog signals of the motion encoder are sampled and processed by the AGC circuit so as to adjust the gains applied to such analog signals.
    Type: Application
    Filed: February 9, 2009
    Publication date: August 12, 2010
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Patent number: 7732754
    Abstract: According to one embodiment, there is provided an optical encoder having a photodetector array comprising motion detection photodetectors and at least one reference photodetector vertically offset from the motion detection photodetectors. The output signal generated by the at least one reference photodetectors is employed to correct undesired variations in the amplitudes of the output signals generated by the motion detection photodetectors. Such variations typically arise from various mechanical and optical misalignments in the optical encoder, and are compensated for by using the reference output signal to add to or subtract from, as required, the amplitudes of motion detection output signals.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: June 8, 2010
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Kheng Hin Toh, Gim Eng Chew, Nanta-Kumar Payandi
  • Patent number: 7709784
    Abstract: According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: May 4, 2010
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Patent number: 7649220
    Abstract: A photodetector and method for making the same is disclosed. The photodetector includes a substrate having first, second, and third photodiodes and first and second pigment filter layers. The first, second, and third photodiodes generate first, second, and third photodiode output signals, respectively, each photodiode output signal being indicative of a light intensity incident on that photodiode and a dark current that is independent of the light intensity. The first and second pigment filter layers overlie the first and second photodiodes while a layer having both the first and second pigment filter layers overlie the third photodiode. An output circuit combines the first and third photodiode output signals to provide a first corrected output signal and combines the second and third photodiode output signals to provide a second corrected output signal.
    Type: Grant
    Filed: March 29, 2007
    Date of Patent: January 19, 2010
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Farn Hin Chen, Gim Eng Chew, Boon Keat Tan
  • Publication number: 20090302954
    Abstract: Disclosed are various embodiments of temperature-compensated relaxation oscillator circuits that may be fabricated using conventional CMOS manufacturing techniques. The relaxation oscillator circuits described herein exhibit superior low temperature coefficient performance characteristics, and do not require the use of expensive off-chip high precision resistors to effect temperature compensation. Positive and negative temperature coefficient resistors arranged in a resistor array offset one another to provide temperature compensation in the relaxation oscillator circuit.
    Type: Application
    Filed: June 6, 2008
    Publication date: December 10, 2009
    Applicant: Avago Technologies ECBU (Singapore) Ple. Ltd.
    Inventors: Alex Jianzhong Chen, Gim Eng Chew, Tong Tee Tan, Kok Chin Pan
  • Publication number: 20090272885
    Abstract: According to one embodiment, there is provided a device and method for correcting code wheel misalignment which employs upper and lower code wheel misalignment photodetectors positioned above and below at least first and second motion detection photodetectors. According to other embodiments, there are provided a device and method for automatically setting the gain of an output circuit in an optical encoder. Still further embodiments of optical encoders combine the code wheel misalignment and automatic gain control features of the invention.
    Type: Application
    Filed: April 30, 2008
    Publication date: November 5, 2009
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd.
    Inventors: Chung Min Thor, Mei Yee Ng, Gim Eng Chew
  • Publication number: 20090272884
    Abstract: According to one embodiment, there is provided an optical encoder having a photodetector array comprising motion detection photodetectors and at least one reference photodetector vertically offset from the motion detection photodetectors. The output signal generated by the at least one reference photodetectors is employed to correct undesired variations in the amplitudes of the output signals generated by the motion detection photodetectors. Such variations typically arise from various mechanical and optical misalignments in the optical encoder, and are compensated for by using the reference output signal to add to or subtract from, as required, the amplitudes of motion detection output signals.
    Type: Application
    Filed: April 30, 2008
    Publication date: November 5, 2009
    Applicant: Avago Technologies ECBU (Singapore) Pte. Ltd.
    Inventors: Kheng Hin Toh, Gim Eng Chew, Nanta-Kumar Payandi
  • Patent number: 7609291
    Abstract: A device and method for producing an enhanced color image of a scene of interest captures a grayscale image of the scene of interest using a flash of infrared light and a color image of the scene of interest without using any flash of infrared light. The grayscale information from the grayscale image and the visible color information from the color image are combined to produce the enhanced color image.
    Type: Grant
    Filed: December 7, 2005
    Date of Patent: October 27, 2009
    Assignee: Avago Technologies ECBU IP (Singapore) Pte. Ltd.
    Inventors: Chin Hin Oon, Kean Loo Keh, Farn Hin Chen, Eit Thian Yap, Gim Eng Chew, Kee Yean Ng, Thye Linn Mok, Wool Kin Goon, Rene P. Helbing, Janet Bee Yin Chua