Abstract: A physiological condition detecting method detects pulse waves from the body of a patient, and creates the envelope of the pulse waves by connecting every peak of the pulse waves. It determines that the patient is in non-REM sleep, if the envelope fluctuates regularly. It determines that the patient is in REM sleep, if the envelope fluctuates irregularly. Further the method calculates and normalizes the amplitude and period of the envelope. It determines whether the patient has obstructive sleep apnea syndrome based on the normalized amplitude. It determines whether the patient has central sleep apnea syndrome based on the normalized period. It determines that the patient has mixed sleep apnea syndrome based on the normalized amplitude and the normalized period.

Abstract: A pleural pressure is predicted from pleural pressure based upon pulse wave signals, which are continuously produced and picked up in a time sequential manner. A first variation signal indicative of a condition of a variation contained in the pulse wave signals is acquired based upon the pulse wave signals. A second variation signal representative of a condition of a variation contained in the first variation signal is acquired based upon the first variation signal. The pleural pressure is predicted based on a difference between the first variation signal and the second variation signal.

Abstract: A vital signal detecting apparatus comprises an attachable device to be attached to a finger, a sensor having a light-emitting device and a light-receiving device, and a transmitting circuit for transmitting a signal waveform as a pulse wave from the sensor to a pulse wave monitoring unit. The pulse wave detecting unit also has an attachment detecting circuit for detecting whether or not the attachable device is in an attached state by comparing a signal waveform obtained when the light-emitting device is on with a signal waveform obtained when the light-emitting device is off and an operation control circuit for controlling the operation of the sensor, the transmitting circuit and the attachment detecting circuit. Preferably, the light-transmitting plate is disposed above the light-emitting device and the light-receiving device to pass light therethrough, and the light transmitting plate may be an IR-cut filter capable of blocking light of wavelengths greater than 700 nm.

Abstract: A pulse wave sensor includes a detecting element and a sensor body. The pulse wave sensor is worn on the back side of a user's wrist corresponding to the back of the user's hand. The detecting element includes a translucent member on its top, and the translucent member has a convex surface. The detecting element is attached on the back side of the user's wrist by a dedicated belt so that the convex surface of the translucent member is in intimate contact with the surface of the user's skin. The sensor body is attached on the back side of the user's wrist by another dedicated belt so that it is arranged on the detecting element. A cushion is arranged between the sensor body and the detecting element. The pulse wave sensor can stably detect the pulse wave without being affected by the movement of the user's wrist.

Abstract: A method of obtaining information that corresponds to the R—R interval of electrocardiogram from the pulse-wave of a human body. The method is comprised of steps of detecting the pulse-wave of a human body in a predetermined period, differentiating the detected pulse-wave to provide a speed-pulse-wave, measuring intervals of peaks of the speed-pulse-wave, and substituting the intervals of peaks of the speed-pulse-wave for the R—R interval of the electrocardiogram.

Abstract: A pleural pressure is predicted from pleural pressure based upon pulse wave signals, which are continuously produced and picked up in a time sequential manner. A first variation signal indicative of a condition of a variation contained in the pulse wave signals is acquired based upon the pulse wave signals. A second variation signal representative of a condition of a variation contained in the first variation signal is acquired based upon the first variation signal. The pleural pressure is predicted based on a difference between the first variation signal and the second variation signal.

Abstract: A physiological condition detecting method detects pulse waves from the body of a patient, and creates the envelope of the pulse waves by connecting every peak of the pulse waves. It determines that the patient is in non-REM sleep, if the envelope fluctuates regularly. It determines that the patient is in REM sleep, if the envelope fluctuates irregularly. Further the method calculates and normalizes the amplitude and period of the envelope. It determines whether the patient has obstructive sleep apnea syndrome based on the normalized amplitude. It determines whether the patient has central sleep apnea syndrome based on the normalized period. It determines that the patient has mixed sleep apnea syndrome based on the normalized amplitude and the normalized period.

Abstract: A pulse wave sensor includes a detecting element and a sensor body. The pulse wave sensor is worn on the back side of a user's wrist corresponding to the back of the user's hand. The detecting element includes a translucent member on its top, and the translucent member has a convex surface. The detecting element is attached on the back side of the user's wrist by a dedicated belt so that the convex surface of the translucent member is in intimate contact with the surface of the user's skin. The sensor body is attached on the back side of the user's wrist by another dedicated belt so that it is arranged on the detecting element. A cushion is arranged between the sensor body and the detecting element. The pulse wave sensor can stably detect the pulse wave without being affected by the movement of the user's wrist.

Abstract: In an apparatus for detecting a property of a liquid, light is emitted from a light emitting element towards an interface between a liquid to be measured and a prism in an interface channel. Reflected light from the interface is received by a light receiving device, and a refractive index of the liquid is obtained from the total reflection critical angle. A cleaning member capable of contacting the interface by the flow of the liquid is provided. The cleaning member may be a small body or a floating member, a tape/string member having one end fixed to a channel wall, or a wiper swingable by the flow of the liquid.