Method and apparatus for the automatic calibration of signals employed
in oximetry
    1.
    发明授权
    Method and apparatus for the automatic calibration of signals employed in oximetry 失效
    用于自动校准血氧饱和度信号的方法和装置

    公开(公告)号:US4913150A

    公开(公告)日:1990-04-03

    申请号:US897663

    申请日:1986-08-18

    摘要: Under the present invention, a method and apparatus are provided for compensating for the effect temperature variations have on the wavelength of light emitted by the oximeter sensor light sources (40, 42). In pulse oximetry, LEDs are typically employed to expose tissue to light at two different wavelengths. The light illuminating the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by the oximeter circuitry to produce an indication of oxygen saturation. Because current oximetry techniques are dependent upon the wavelengths of light emitted by the LEDs (40-42), the wavelengths must be known. Even when predetermined combinations of LEDs (40-42) having relatively precise wavelengths are employed, variations in the wavelength of light emitted may result. Because the sensor (12) may be exposed to a significant range of temperatures while in use, the effect of temperature on the wavelengths may be significant. To compensate for this effect, a temperature sensor (50) is included in the sensor (12) to produce a signal indicative of sensor temperature. This signal is interpreted by the oximeter circuitry including, for example, a microcomputer (16), where the effect of temperature on wavelength is compensated for. In a preferred arrangement, this compensation takes the form of a computation of an alternative calibration curve from which the oxygen saturation is indicated, given a particular processing of signals from the detector (38).

    Feedback-controlled method and apparatus for processing signals used in
oximetry
    2.
    发明授权
    Feedback-controlled method and apparatus for processing signals used in oximetry 失效
    用于处理血氧饱和度信号的反馈控制方法和装置

    公开(公告)号:US4819646A

    公开(公告)日:1989-04-11

    申请号:US897664

    申请日:1986-08-18

    CPC分类号: A61B5/14551

    摘要: A feedback control system is disclosed for use in processing signals employed in pulse transmittance oximetry. The signals are produced in response to light transmitted through, for example, a finger at two different wavelengths. Each signal includes a slowly varying baseline component representing the relatively fixed attenuation of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation produced by the changing blood volume and oxygen saturation within the finger. The signals are processed by the feedback control system before being converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The feedback control system includes a controllable offset subtractor (66), a programmable gain amplifier (68), controllable drivers (44) for the light sources (40,42), and the microcomputer (16). The microcomputer receives signals from the offset subtractor (66), gain amplifier (68), drivers (44) and A/D converter (72) to produce signals that control the function of the subtractor (66) and drivers (44) in the following manner. Normally, the drivers (44) are maintained within a predetermined current range. In the event the microcomputer (16) senses an output from the converter (72) that is not within a predetermined range, the drive signal is adjusted to produce an acceptable signal. The magnitude of the offset removed by the subtractor (66), as controlled by the microcomputer (16), is maintained at a constant level when the converter (72) output is within a first predetermined range and is a predetermined function of the converter (72) output when that output falls within a second predetermined range.

    Method and apparatus for offsetting baseline portion of oximeter signal
    3.
    发明授权
    Method and apparatus for offsetting baseline portion of oximeter signal 失效
    用于抵消血氧计信号基线部分的方法和装置

    公开(公告)号:US4892101A

    公开(公告)日:1990-01-09

    申请号:US315330

    申请日:1989-02-24

    IPC分类号: A61B5/00

    CPC分类号: A61B5/14551

    摘要: A feedback control system is disclosed for use in processing signals employed in pulse transmittance oximetry. The signals are produced in response to light transmitted through, for example, a finger at two different wavelengths. Each signal includes a slowly varying baseline component representing the relatively fixed attenuation of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation produced by the changing blood volume and oxygen saturation within the finger. The signals are processed by the feedback control system before being converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The feedback control system includes a controllable offset subtractor (66), a programmable gain amplifier (68), controllable drivers (44) for the light sources (40, 42), and the microcomputer (16). The microcomputer (16) receives signals from the offset subtractor (66), gain amplifier (68), drivers (44) and A/D converter (72) to produce signals that control the function of the subtractor (66) and drivers (44) in the following manner. Normally, the drivers ( 44) are maintained within a predetermined current range. In the event the microcomputer (16) senses an output from the converter (72) that is not within a predetermined range, the drive signal is adjusted to produce an acceptable signal. The magnitude of the offset removed by the subtractor (66), as controlled by the microcomputer (16), is maintained at a constant level when the converter (72) output is within a first predetermined range and is a predetermined function of the converter (72) output when that output falls within a second predetermined range.

    摘要翻译: 公开了一种反馈控制系统,用于处理脉冲透射比率测定中使用的信号。 信号是响应于透过例如两个不同波长的手指的光产生的。 每个信号包括缓慢变化的基线分量,其表示由骨,组织,皮肤和头发产生的光的相对固定的衰减。 信号还包括表示由手指内的血液体积变化和氧饱和度产生的衰减的脉动成分。 这些信号由模拟数字(A / D)转换器(72)转换之前由反馈控制系统处理,用于微计算机(16)的后续分析。 反馈控制系统包括可控偏移减法器(66),可编程增益放大器(68),用于光源(40,42)的可控驱动器(44)和微计算机(16)。 微型计算机(16)从偏移减法器(66),增益放大器(68),驱动器(44)和A / D转换器(72)接收信号,以产生控制减法器(66)和驱动器(44)的功能的信号 )。 通常,驱动器(44)保持在预定的电流范围内。 在微计算机(16)感测到转换器(72)的输出不在预定范围内的情况下,调节驱动信号以产生可接受的信号。 当转换器(72)输出在第一预定范围内并且是转换器的预定功能时,被微计算机(16)控制的减法器(66)去除的偏移量的幅度保持在恒定水平 72)当该输出处于第二预定范围内时输出。

    Apparatus for the automatic calibration of signals employed in oximetry
    4.
    发明授权
    Apparatus for the automatic calibration of signals employed in oximetry 失效
    用于自动校准血氧饱和度信号的装置

    公开(公告)号:US5259381A

    公开(公告)日:1993-11-09

    申请号:US377722

    申请日:1989-07-10

    IPC分类号: A61B5/00 A61B5/024 G01N21/27

    摘要: Under the present invention, a method and apparatus are provided for compensating for the effect temperature variations have on the wavelength of light emitted by the oximeter sensor light source (40, 42). In pulse oximetry, LEDs (40, 42) are typically employed to expose tissue to light at two different wavelengths. The light illuminating the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by the oximeter circuitry to produce an indication of oxygen saturation. Because current oximetry techniques are dependent upon the wavelengths of light emitted by the LEDs (40, 42), the wavelengths must be known. Even when predetermined combinations of LEDs (40, 42) having relatively precise wavelengths are employed, variations in the wavelength of light emitted may result. Because the sensor (12) may be exposed to a significant range of temperatures while in use, the effect of temperature on the wavelengths may be significant. To compensate for this effect, a temperature sensor (50) is included in the sensor (12) to produce a signal indicative of sensor temperature. This signal is interpreted by the oximeter circuitry including, for example, a microcomputer (16), where the effect of temperature on wavelength is compensated for. In a preferred arrangement, this compensation takes the form of a computation of an alternative calibration curve from which the oxygen saturation is indicated, given a particular processing of signals from the detector (38).

    摘要翻译: 在本发明中,提供了一种方法和装置,用于补偿由血氧计传感器光源(40,42)发射的光的波长对温度变化的影响。 在脉搏血氧测定中,通常使用LED(40,42)来将组织暴露于两个不同波长的光。 照射组织的光被检测器(38)接收,其中产生与光强度成比例的信号。 然后,这些信号由血氧计电路处理以产生氧饱和度的指示。 因为目前的血氧测定技术取决于由LED(40,42)发射的光的波长,所以波长必须是已知的。 即使当使用具有相对精确波长的LED(40,42)的预定组合时,也可能导致发射的光的波长的变化。 因为传感器(12)可能在使用时暴露于显着的温度范围内,所以温度对波长的影响可能是显着的。 为了补偿这种效果,传感器(12)中包括温度传感器(50),以产生指示传感器温度的信号。 该信号由包括例如温度对波长的影响得到补偿的微计算机(16)的血氧计电路解释。 在优选的布置中,给定来自检测器(38)的信号的特定处理,该补偿采用计算替代校准曲线的形式,从该氧化饱和度被指示。

    Method and apparatus for indicating perfusion and oxygen saturation
trends in oximetry
    5.
    发明授权
    Method and apparatus for indicating perfusion and oxygen saturation trends in oximetry 失效
    用于指示血氧饱和度的灌注和氧饱和度趋势的方法和装置

    公开(公告)号:US4869253A

    公开(公告)日:1989-09-26

    申请号:US897662

    申请日:1986-08-18

    CPC分类号: A61B5/14551 A61B5/7207

    摘要: The present invention discloses a method and apparatus for indicating perfusion and oxygen saturation trends in oximetry. In transmittance and reflectance oximetry, LEDs (40, 42) are typically employed to expose tissue to light at two different wavelengths. The light transmitted through, or reflected by, the tissue is received by a detector (38) where signals proportional to the intensity of light are produced. These signals are then processed by oximeter circuitry (14, 16) to determine oxygen saturation, pulse rate, and perfusion. Displays (20) are provided including a display (132, 134) of the change in the oxygen saturation during a specified interval. This display may include first (132) and second (134) trend indication displays that indicate when the oxygen saturation has either been increasing or decreasing at a rate in excess of some predetermined level. Preferably, these displays are triangular, upwardly and downwardly directed light-emitting diodes. A digital display (138) of the change in oxygen saturation may also be provided. A second type of display included provides pulse and perfusion information, with the perfusion being displayed as a logarithmic function of the actual perfusion. This display comprises an aligned array of light-emitting diodes (136) with the number of LED's lit imaging the plethysmigraphic waveform, peak to peak scaling is employed which is indicative of signal level and perfusion.

    Method and apparatus for improving the accuracy of pulse transmittance
oximeter
    6.
    发明授权
    Method and apparatus for improving the accuracy of pulse transmittance oximeter 失效
    提高脉搏透射率血氧仪精度的方法和装置

    公开(公告)号:US5285782A

    公开(公告)日:1994-02-15

    申请号:US822543

    申请日:1992-01-17

    IPC分类号: A61B5/00 G01N33/487 G06F19/00

    CPC分类号: A61B5/14551

    摘要: A method and apparatus for accurately determining a blood parameter that is calculated by measuring the transmittance of light through tissue having blood flowing therein is disclosed. A plurality of transmittance of light measurements are obtained for each transmittance of light parameter. The arithmetic mean of each transmittance of light parameter is calculated from the plurality of measurements. The arithmetic means are used to calculate the blood parameter from known formulations.

    摘要翻译: 公开了一种用于准确地测定血液参数的方法和装置,该方法和装置是通过测量透过具有血液流过的组织的透射率来计算的。 针对光参数的每个透射率获得多个光测量的透射率。 从多个测量中计算光参数的每个透射率的算术平均值。 算术手段用于从已知配方计算血液参数。

    Noise insensitive pulse transmittance oximeter
    7.
    发明授权
    Noise insensitive pulse transmittance oximeter 失效
    噪声不敏感脉冲透射度血氧仪

    公开(公告)号:US5246002A

    公开(公告)日:1993-09-21

    申请号:US833930

    申请日:1992-02-11

    IPC分类号: A61B5/00 A61B5/024

    摘要: A noise insensitive pulse transmittance oximeter (11) is disclosed. Two LEDs (21 and 23) are included in the pulse transmittance oximeter. The LEDs alternately emit a red light pulse and an infrared light pulse. A detector (13) detects corresponding red transmittance pulses and infrared transmittance pulses that are indicative of the amount of light transmitted through tissue having blood flowing therein. A microprocesser (29) determines the peak and valley values of the red transmittance pulses and infrared transmittance pulses over a cycle. The difference between the peak and valley values for the red transmittance pulses and infrared transmittance pulses are calculated by the microprocessor. The microprocessor generates control signals that vary the intensity of the LEDs until the differences between the peak and valley values of the red transmittance pulses and infrared transmittance pulses are substantially equal.

    摘要翻译: 公开了一种噪声不敏感脉冲透射式血氧计(11)。 两个LED(21和23)包含在脉冲透射率血氧计中。 LED交替发出红光脉冲和红外光脉冲。 检测器(13)检测相应的红色透射脉冲和红外透射脉冲,其指示透过其中流过血液的组织的光量。 微处理器(29)确定红色透射脉冲的峰谷值和红外透射脉冲的周期。 红色透射脉冲和红外透射脉冲的峰值和谷值之间的差值由微处理器计算。 微处理器产生改变LED的强度的控制信号,直到红色透射脉冲和红外透射脉冲的峰值和谷值之间的差异基本相等。

    Humidity sensor
    8.
    发明授权
    Humidity sensor 失效
    湿度传感器

    公开(公告)号:US5004700A

    公开(公告)日:1991-04-02

    申请号:US561377

    申请日:1990-08-01

    CPC分类号: H01L29/4966 G01N27/4141

    摘要: A method of making a humidity sensor comprises providing a host device constituted by a semi-conductor substrate (10) and a gate insulator (13) of an insulated gate field effect transistor, forming a layer (14) of poly (vinyl) alcohol (PVA) on the exposed surface of the insulator, heat treating the layer to crystallize and stabilize the PVA, and forming a gate electrode (15) on the PVA layer, so that the gate electrode is porous allowing ambient water vapor to be absorbed by the PVA which, in response, undergoes a change of bulk dielectric constant, thereby causing a change in gate capacitance of the transistor resulting in a detectable change of electrical conductivity in the drain source channel.

    摘要翻译: 制造湿度传感器的方法包括提供由半导体衬底(10)和绝缘栅场效应晶体管的栅极绝缘体(13)构成的主体器件,形成聚(乙烯醇)(14)层(14) PVA)在绝缘体的暴露表面上,热处理该层以使PVA结晶并稳定,并在PVA层上形成栅电极(15),使得栅电极是多孔的,允许环境水蒸汽被 PVA,其响应地经历体介电常数的变化,从而引起晶体管的栅极电容的变化,导致漏极源极通道中的电导率的可检测变化。

    Multiple-pulse method and apparatus for use in oximetry
    9.
    发明授权
    Multiple-pulse method and apparatus for use in oximetry 失效
    用于血氧定量的多脉冲方法和装置

    公开(公告)号:US4859056A

    公开(公告)日:1989-08-22

    申请号:US897661

    申请日:1986-08-18

    CPC分类号: A61B5/14551

    摘要: The disclosed invention is for use in extracting more accurate information from signals employed in pulse oximetry. Basically, pulse oximetry involves the illumination of arterial blood flowing in tissue with light at two wavelengths. Upon emerging from the tissue the light is received by a detector (38) that produces signals that are proportional to the intensity of the light received at each of the wavelengths. Each signal includes a slowly varying baseline component representing the attenuation .beta.(t) of light produced by bone, tissue, skin, and hair. The signals also include pulsatile components representing the attenuation .alpha.(t) produced by the changing blood volume and oxygen saturation within the finger. The signals produced by the detector (38) are converted by an analog-to-digital (A/D) converter (72) for subsequent analysis by a microcomputer (16). The microcomputer (16) extracts the following information from the signal corresponding to each wavelength. V.sub.H is determined to be the signal magnitude at a second pulse diastole. V.sub.L is, similarly, the signal magnitude at systole of the same pulse. A term .DELTA.V is identified equal in value to the difference in signal magnitudes at the adjacent systoles. Finally, values are determined for .DELTA.ts and .DELTA.tp, being the interval between an adjacent systole and diastole and the pulse period, respectively. The microcomputer (16) then determines a value for R.sub.OS in accordance with the relationship: ##EQU1## Empirically derived oxygen saturation curves are used to develop an indication of the oxygen saturation from the value of R.sub.OS computed.