SLEEPINESS JUDGING DEVICE

• US 20100234747A1
• Filed: 08/01/2008
• Published: 09/16/2010
• Est. Priority Date: 08/06/2007
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Hatakeyama, Yoshiyuki
• Granted Patent: US 8,346,352 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61B 5/4806 Sleep evaluation A61B5/4821 takes precedence; devices for inducing sleep A61M21/02

Abstract

The object is to provide a drowsiness detecting device for detecting strong drowsiness to become a dozing state. A drowsiness detecting device comprises a sympathetic parameter acquiring unit for acquiring a parameter concerning a sympathetic nerve of a subject, a parasympathetic parameter acquiring unit for acquiring a parameter concerning a parasympathetic nerve of the subject, a sympathetic increase determining unit for determining whether the sympathetic parameter is greater than a sympathetic threshold or not, and a drowsiness determining unit for determining drowsiness of the subject according to an increase/decrease relationship between the sympathetic and parasympathetic parameters when the sympathetic increase determining unit determines that the sympathetic parameter is greater than the sympathetic threshold.

Claims

1. A drowsiness determining device comprising:

a sympathetic parameter acquiring unit for acquiring a parameter concerning a sympathetic nerve of a subject;

a parasympathetic parameter acquiring unit for acquiring a parameter concerning a parasympathetic nerve of the subject;

a sympathetic increase determining unit for determining whether the sympathetic parameter acquired by the sympathetic parameter acquiring unit is greater than a sympathetic threshold or not; and

a drowsiness determining unit for determining drowsiness of the subject according to an increase/decrease relationship between the sympathetic parameter acquired by the sympathetic parameter acquiring unit and the parasympathetic parameter acquired by the parasympathetic parameter acquiring unit when the sympathetic increase determining unit determines that the sympathetic parameter is greater than the sympathetic threshold.

2. A drowsiness determining device according to claim 1, wherein the sympathetic increase determining unit determines that the sympathetic parameter is greater than the sympathetic threshold when a duration during which the sympathetic parameter acquired by the sympathetic parameter acquiring unit is greater than the sympathetic threshold is longer than a time threshold.

3. A drowsiness determining device according to claim 1, wherein the parasympathetic parameter acquiring unit acquires the parasympathetic parameter according to an increase/decrease direction of a heartbeat fluctuation high frequency component.

4. A drowsiness determining device according to claim 1, further comprising a parasympathetic increase determining unit for determining whether the parasympathetic parameter acquired by the parasympathetic parameter acquiring unit is greater than a parasympathetic threshold or not;

wherein the drowsiness determining unit determines that the subject is in a strongly drowsy state when the parasympathetic increase determining unit determines that the parasympathetic parameter is greater than the parasympathetic threshold after the sympathetic increase determining unit determines that the sympathetic parameter is smaller than the sympathetic threshold in a case where the sympathetic increase determining unit determines that the sympathetic parameter is greater than the sympathetic threshold.

5. A drowsiness determining device according to claim 1, further comprising a parasympathetic increase determining unit for determining whether the parasympathetic parameter acquired by the parasympathetic parameter acquiring unit is greater than a parasympathetic threshold or not;

wherein the drowsiness determining unit determines that the subject is in a strongly drowsy state when the parasympathetic increase determining unit determines that the parasympathetic parameter is greater than the parasympathetic threshold while the sympathetic increase determining unit keeps determining that the sympathetic parameter is greater than the sympathetic threshold in a case where the sympathetic increase determining unit determines that the sympathetic parameter is greater than the sympathetic threshold.