Non-contact photoplethysmographic pulse measurement device and oxygen saturation and blood pressure measurement devices using the same

• US 9,031,629 B2
• Filed: 03/20/2009
• Issued: 05/12/2015
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: SNU R&DB Foundation (Seoul National University)
• Original Assignee: SNU R&DB Foundation (Seoul National University)
• Inventors: Park, Kwang Suk, Baek, Hyun Jae
• Primary Examiner(s): Dougherty, Sean
• Assistant Examiner(s): Stout, Michael C
• Application Number:
  US12/408,295
• Publication Number:
  US 20100185068A1
• Time in Patent Office: 2,244 Days
• Field of Search: 600/485, 600/490, 600/336, 600/544, 600/310, 600/324, 600/301, 600/508, 600/513, 367/7
• 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]
• CPC Class Codes: A61B 5/33 specially adapted for cooperation with other devices

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 blood pressure measurement device, comprising:

a non-contact photoplethysmographic (PPG) pulse measurement device;

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,

wherein the non-contact photoplethysmographic (PPG) pulse measurement device comprises;

a sensing unit including at least two light emitting units for emitting light into a human body without the light emitting units making direct contact with skin of a user, and a light receiving unit 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 preset Direct Current (DC) signal value and to be decreased when the value of the ripple-free component is greater than said preset Direct Current (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, wherein said at least two light emitting units are arranged on a circumference of a circle having a predetermined radius and the light receiving unit is arranged at the center of the circle, and

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, wherein the amplifier-attached electrode of the non-contact electrocardiogram measurement device is installed on both suitable sides of the back of a chair to measure the electrocardiogram of a user in an unconstrained manner.

2. The non-contact blood pressure measurement device according to claim 1, wherein said at least two light emitting units include three light emitting units.

3. The non-contact blood pressure measurement device according to claim 2, wherein said three light emitting units are arranged on a circumference of a circle and spaced apart from each other at equal 120°

intervals around the light receiving unit.

4. The non-contact blood pressure measurement device according to claim 1, 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.

5. The non-contact blood pressure measurement device according to claim 1,

wherein the sensing unit of the non-contact PPG pulse measurement device is installed at a predetermined location on the top surface of a chair configured to contact a user'"'"'s hips to measure the PPG pulse of the user on a thigh portion of the user in an unconstrained manner.

6. The non-contact blood pressure measurement device according to claim 1, wherein said at least two light emitting units include three light emitting units.

7. The non-contact blood pressure measurement device according to claim 1, wherein the preset Direct Current (DC) signal value preset in the microprocessor unit is 1V to 2V.

8. The non-contact blood pressure measurement device according to claim 1,

wherein the sensing unit of the non-contact PPG pulse measurement device is installed at a predetermined location on the top surface of a chair configured to come into contact with a user'"'"'s hips to measure the PPG pulse of the user on a thigh portion of the user in an unconstrained manner.

9. The non-contact blood pressure measurement device according to claim 1, wherein said at least two light emitting units include three light emitting units.

10. The non-contact blood pressure measurement device according to claim 1, wherein the preset Direct Current (DC) signal value preset in the microprocessor unit is 1V to 2V.

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

a non-contact photoplethysmographic (PPG) pulse measurement device;

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,

wherein the non-contact photoplethysmographic (PPG) pulse measurement device comprises;

a sensing unit including a light emitting unit for emitting light into a human body without the light emitting unit 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 preset Direct Current (DC) signal value and to be decreased when the value of the ripple-free component is greater than said preset Direct Current (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,

wherein the light emitting unit is arranged at a center of a circle having a predetermined radius, and said at least two light receiving units are arranged on a circumference of the circle, and

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, wherein the amplifier-attached electrode of the non-contact electrocardiogram measurement device is installed on both suitable sides of the back of a chair to measure the electrocardiogram of a user in an unconstrained manner.

12. The non-contact blood pressure measurement device according to claim 11, wherein said at least two light receiving units include three light receiving units.

13. The non-contact blood pressure measurement device according to claim 12, wherein said three light receiving units are arranged on a circumference of a circle and spaced apart from each other at equal 120°

intervals around the light emitting unit.

14. The non-contact blood pressure measurement device according to claim 12, wherein said three light receiving units are arranged on a circumference of a circle and spaced apart from each other at equal 120°

intervals around the light emitting unit.

15. The non-contact blood pressure measurement device according to claim 11, 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.

16. The non-contact blood pressure measurement device according to claim 11, wherein said three light emitting units are arranged on a circumference of a circle and spaced apart from each other at equal 120°

intervals around the light receiving unit.