NON-CONTACT PHOTOPLETHYSMOGRAPHIC PULSE MEASUREMENT DEVICE AND OXYGEN SATURATION AND BLOOD PRESSURE MEASUREMENT DEVICES USING THE SAME

• US 20100185068A1
• Filed: 03/20/2009
• Published: 07/22/2010
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: Seoul National University R&DB Foundation (Seoul National University)
• Original Assignee: Seoul National University R&DB Foundation (Seoul National University)
• Inventors: PARK, Kwang Suk, Baek, Hyun Jae
• Granted Patent: US 9,031,629 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0255 Recording instruments specially adapted therefor
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]

Abstract

The present invention provides a non-contact photoplethysmographic (PPG) pulse measurement device, and oxygen saturation and blood pressure measurement devices using the PPG pulse measurement device. The PPG pulse measurement device includes a sensing unit including at least two light emitting units for emitting light into a human body without making direct contact with skin, and a light receiving unit for sensing reflected light. A signal separation unit separates output of the sensing unit into a ripple component and a ripple-free component. A microprocessor unit monitors the ripple-free component and compares the ripple-free component with a DC signal value. A luminance adjustment unit adjusts luminance of the light emitting units. A filter and amplification unit eliminates noise from the ripple component. An A/D conversion unit converts output of the filter and amplification unit into a digital signal. A signal transmission unit transmits output of the A/D conversion unit.

Claims

1. A non-contact photoplethysmographic (PPG) pulse measurement device, comprising:

a sensing unit including at least two light emitting units for emitting light into a human body without making direct contact with skin of a user, and a light receiving unit arranged around the light emitting units and configured to sense light reflected from the human body;

a signal separation unit implemented as a filter for separating an output of the sensing unit into a ripple component and a ripple-free component;

a microprocessor unit configured to monitor the ripple-free component, compare a value of the ripple-free component with a preset Direct Current (DC) signal value, and generate a control signal commanding luminance to be increased when the value of the ripple-free component is less than the DC signal value;

a luminance adjustment unit configured to adjust luminance of the light emitting units in response to the control signal output from the microprocessor unit;

a filter and amplification unit including a filter for eliminating noise from the ripple component and an amplifier for amplifying a filtered ripple component;

an Analog/Digital (A/D) conversion unit configured to convert an output of the filter and amplification unit into a digital signal; and

a signal transmission unit configured to transmit an output of the A/D conversion unit to an external device.

2. The non-contact PPG pulse measurement device according to claim 1, wherein the light emitting units are arranged on a circumference of a circle having a predetermined radius and the light receiving unit is arranged at a center of the circle.

3. The non-contact PPG pulse measurement device according to claim 2, wherein the light emitting units include three light emitting units, which are arranged and spaced apart from each other at equal 120°

intervals around the light receiving unit.

7. The non-contact PPG pulse measurement device according to claim 1, wherein the DC signal value preset in the microprocessor unit is 1V to 2V.

14. A non-contact blood pressure measurement device, comprising:

the non-contact PPG pulse measurement device according to claim 1;

a non-contact electrocardiogram measurement device for measuring an electrocardiogram without making direct contact with skin; and

a signal processing device for outputting blood pressure information using both a signal transmitted from the non-contact PPG pulse measurement device and a signal transmitted from the non-contact electrocardiogram measurement device.

15. The non-contact blood pressure measurement device according to claim 14, wherein the non-contact electrocardiogram measurement device comprises:

an amplifier-attached electrode;

a filter and amplification unit including a filter for eliminating noise from a signal output from the amplifier-attached electrode, and an amplifier for amplifying a filtered signal;

an A/D conversion unit for converting an output of the filter and amplification unit into a digital signal; and

a signal transmission unit for transmitting an output of the A/D conversion unit to the signal processing device.

16. The non-contact blood pressure measurement device according to claim 14, wherein the signal processing device comprises:

a pulse arrival time calculation unit for calculating a pulse arrival time using the signals transmitted from the non-contact PPG pulse measurement device and the non-contact electrocardiogram measurement device;

a blood pressure information output unit for outputting blood pressure information corresponding to the pulse arrival time calculated by the pulse arrival time calculation unit in conjunction with a blood pressure information database; and

a display unit for displaying an output of the blood pressure information output unit on a screen.

4. A non-contact photoplethysmographic (PPG) pulse measurement device, comprising:

a sensing unit including a light emitting unit for emitting light into a human body without making direct contact with skin, and at least two light receiving units arranged around the light emitting unit and configured to sense light reflected from the human body;

a signal separation unit implemented as a filter for separating an output of the sensing unit into a ripple component and a ripple-free component;

a microprocessor unit configured to monitor the ripple-free component, compare a value of the ripple-free component with a preset Direct Current (DC) signal value, and generate a control signal commanding luminance to be increased when the value of the ripple-free component is less than the DC signal value;

a luminance adjustment unit configured to adjust luminance of the light emitting units in response to the control signal output from the microprocessor unit;

a filter and amplification unit including a filter for eliminating noise from the ripple component and an amplifier for amplifying a filtered ripple component;

an Analog/Digital (A/D) conversion unit configured to convert an output of the filter and amplification unit into a digital signal; and

a signal transmission unit configured to transmit an output of the A/D conversion unit to an external device.

5. The non-contact PPG pulse measurement device according to claim 4, wherein the light emitting unit is arranged at a center of a circle having a predetermined radius, and the light receiving units are arranged on a circumference of the circle.

6. The non-contact PPG pulse measurement device according to claim 5, wherein the light receiving units include three light receiving units, which are arranged and spaced apart from each other at equal 120°

intervals around the light emitting unit.

8. A non-contact oxygen saturation measurement device, comprising:

a sensing unit including at least four light emitting units for emitting light having different wavelengths into a human body without making direct contact with skin, and a light receiving unit arranged around the light emitting units and configured to sense light reflected from the human body, wherein a number of light emitting units that emit light having each wavelength is uniform;

a signal separation unit configured to classify an output of the sensing unit into respective wavelengths and separate the output into a ripple component and a ripple-free component for each wavelength;

a microprocessor unit configured to monitor the ripple-free component, compare a value of the ripple-free component with a preset Direct Current (DC) signal value, and generate a control signal commanding luminance to be increased when the value of the ripple-free component is less than the DC signal value;

a luminance adjustment unit configured to adjust luminance of the light emitting units in response to the control signal output from the microprocessor unit;

a filter and amplification unit including a filter for eliminating noise from the ripple component and an amplifier for amplifying a filtered ripple component;

an Analog/Digital (A/D) conversion unit configured to convert an output of the filter and amplification unit into a digital signal; and

a signal transmission unit configured to transmit an output of the A/D conversion unit to an external device.

9. The non-contact oxygen saturation measurement device according to claim 8, wherein the light emitting units are arranged on a circumference of a circle having a predetermined radius and the light receiving unit is arranged at a center of the circle, wherein three light emitting units for emitting red light are included in the light emitting units to correspond to three light emitting units for emitting infrared light.

10. The non-contact oxygen saturation measurement device according to claim 9, wherein the light emitting units are configured such that the light emitting units for emitting the infrared light and the light emitting units for emitting the red light are sequentially and alternately arranged so that they are arranged and spaced apart from each other at equal 60°

intervals around the light receiving unit.

11. A non-contact oxygen saturation measurement device, comprising:

a sensing unit including at least two light emitting units for emitting light having different wavelengths into a human body without making direct contact with skin and at least two light receiving units arranged around the light emitting units and configured to sense light reflected from the human body, wherein a number of light emitting units that emit light having each wavelength is uniform;

a signal separation unit configured to classify an output of the sensing unit into respective wavelengths and separate the output into a ripple component and a ripple-free component for each wavelength;

a microprocessor unit configured to monitor the ripple-free component, compare a value of the ripple-free component with a preset Direct Current (DC) signal value, and generate a control signal commanding luminance to be increased when the value of the ripple-free component is less than the DC signal value;

a luminance adjustment unit configured to adjust luminance of the light emitting units in response to the control signal output from the microprocessor unit;

a filter and amplification unit including a filter for eliminating noise from the ripple component and an amplifier for amplifying a filtered ripple component;

an Analog/Digital (A/D) conversion unit configured to convert an output of the filter and amplification unit into a digital signal; and

a signal transmission unit configured to transmit an output of the A/D conversion unit to an external device.

12. The non-contact oxygen saturation measurement device according to claim 11, wherein the light emitting units are arranged in parallel around a center of a circle having a predetermined radius so that one light emitting unit for emitting red light is included to correspond to one light emitting unit for emitting infrared light, and the light receiving units are arranged on a circumference of the circle.

13. The non-contact oxygen saturation measurement device according to claim 12, wherein the light receiving units include three light receiving units, which are arranged and spaced apart from each other at equal 120°

intervals around a center of the circle on which the light receiving units are arranged.