Sensor devices and mobile devices including sensor devices

Abstract

To provide a sensor device and a mobile device including the same which may improve noise characteristics, by encoding current signals generated by a plurality of photodiodes, processing the signals by a single signal processing module, and decoding an output of the signal processing module into data signals corresponding to the current signals.SOLUTION: A sensor device according to one example of the present invention includes a sensor array including a plurality of photodiodes configured to generate current signals in response to light, an encoder configured to encode the current signals to generate a plurality of analog signals and output the plurality of analog signals sequentially, a signal processing module configured to apply signal processing to the analog signals, received from the encoder, to generate digital signals, and a decoder configured to decode the digital signals, received from the signal processing module, to generate a plurality of data signals corresponding to the current signals.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a sensor device and a mobile device including a sensor device. [Background technology]

[0002] Recently, there has been a trend towards equipping various mobile devices, including wearable devices, with sensor devices such as biosensors that can collect biometric information and provide useful services to users. Sensor devices for collecting biometric information may include photodiodes that generate electric charge in response to light, and the electric charge generated by the photodiode can be processed as a signal to determine biometric information. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] One of the problems that the technical concept of the present invention aims to solve is to provide a sensor device and a mobile device including the sensor device that can improve noise characteristics by encoding current signals generated by multiple photodiodes, processing the signals with a single signal processing module, and decoding the output of the signal processing module into a data signal corresponding to the current signal. [Means for solving the problem]

[0004] A sensor device according to one embodiment of the present invention includes a sensor array having a plurality of photodiodes that generate a current signal in response to light, an encoder that encodes the current signal to generate a plurality of analog signals and outputs the plurality of analog signals sequentially, a signal processing module that processes the plurality of analog signals received from the encoder to generate a digital signal, and a decoder that decodes the digital signal received from the signal processing module to generate a plurality of data signals corresponding to the current signal.

[0005] A sensor device according to one embodiment of the present invention includes a plurality of photodiodes that generate current signals in response to light, an encoder that includes a multiplier and an adder connected to the photodiodes via a plurality of analog channels and operating by a predetermined orthogonal code, and sequentially outputs a plurality of analog signals encoded with the current signals via one input channel, a signal processing module that includes an input terminal connected to the input channel and continuously outputs a plurality of digital signals corresponding to the analog signals via an output terminal, a decoder connected to the output terminal and outputs a plurality of data signals decoded by the inverse of an orthogonal matrix corresponding to the orthogonal code via a plurality of digital channels, and a processor that generates information corresponding to the current signals using the data signals.

[0006] A mobile device according to one embodiment of the present invention includes a substrate, a plurality of photodiodes mounted on the first surface of the substrate and generating current signals in response to light incident from an object, a signal processing device mounted on the first surface or a second surface of the substrate facing the first surface and converting the current signals into a plurality of data signals, and a processor that acquires biological information using the data signals. The signal processing device sequentially converts a plurality of analog signals generated using current signals received through a plurality of input channels into a plurality of digital signals, and generates a data signal using the digital signals. [Effects of the Invention]

[0007] According to one embodiment of the present invention, current signals output by multiple photodiodes can be encoded and input to a single signal processing module, and the signal output by the signal processing module can be decoded to generate a data signal corresponding to the current signal. Therefore, in the process of converting the current signal to a data signal, noise reflected in the data signal can be reduced, and noise characteristics such as the noise-to-signal ratio can be improved.

[0008] The diverse yet significant advantages and effects of the present invention are not limited to those described above and can be more easily understood in the process of describing specific embodiments of the present invention. [Brief explanation of the drawing]

[0009] [Figure 1] This is a simplified drawing of a mobile device according to one embodiment of the present invention. [Figure 2] This is a simplified drawing of a mobile device according to one embodiment of the present invention. [Figure 3] This is a simplified drawing of a sensor device according to one embodiment of the present invention. [Figure 4] This is a drawing illustrating the operation of a sensor device according to one embodiment of the present invention. [Figure 5] This is a simplified drawing of a sensor device according to one embodiment of the present invention. [Figure 6] This is a simplified block diagram showing a mobile device according to one embodiment of the present invention. [Figure 7] This is a simplified block diagram showing a sensor device according to one embodiment of the present invention. [Figure 8] This is a simplified drawing of a signal processing module included in a sensor device according to one embodiment of the present invention. [Figure 9] This is a simplified drawing of a sensor device according to one embodiment of the present invention. [Figure 10] This is a timing diagram provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 11a] These drawings are provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 11b] These drawings are provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 12a] These drawings are provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 12b] These drawings are provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 13] This graph is provided to illustrate the operation of a sensor device according to one embodiment of the present invention. [Figure 14]This is a drawing briefly showing a sensor device according to an embodiment of the present invention. [Figure 15] This is a comparative example for explaining a sensor device according to an embodiment of the present invention. [Figure 16] This is a comparative example for explaining a sensor device according to an embodiment of the present invention. [Figure 17] This is a comparative example for explaining a sensor device according to an embodiment of the present invention. [Figure 18] This is a block diagram briefly showing a mobile device according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0010] Hereinafter, preferred embodiments of the present invention will be described as follows with reference to the accompanying drawings.

[0011] FIG. 1 and FIG. 2 are drawings briefly showing a mobile device according to an embodiment of the present invention.

[0012] First, referring to FIG. 1, the mobile device 10 can be realized as a watch-type wearable device. The mobile device 10 can include a main body 11 and a strap 12 which is a fixing part for fixing the mobile device 10 to the user's body, for example, the wrist. A display for outputting a screen is provided on the front surface of the main body 11, and screens of various applications including time information, received message information, etc. can be displayed. Depending on the embodiment, an input device 13 for receiving and processing user input can be provided on at least one of the front surface and the side surface of the main body 11. The input device 13 can include a mechanical key, a touch panel, etc.

[0013] A sensor device 14 can be positioned on the rear surface of the main body 11, which comes into contact with the user's body. The sensor device 14 may include a light source that emits light to the user's body, such as the user's wrist, to which the main body 11 is secured by a strap 12 or the like; at least one photodiode that generates an electric current signal in response to the light reflected from the user; and a signal processing module that processes the electric current signal. For example, the mobile device 10 can use the data signals output by the sensor device 14 to determine the user's biometric information, such as heart rate, blood oxygen saturation, and blood pressure.

[0014] Next, referring to Figure 2, the mobile device 20 can also be realized as an ear wearable device. Referring to Figure 2, the mobile device 20 includes an ear strap 21, which is a fixing part that is secured to the user's body, and the user can wear the mobile device 20 by placing the ear strap 21 over the auricle. With the user wearing the mobile device 20, the main body can be inserted into the user's ear canal.

[0015] A sensor device can be mounted on the main body of the mobile device 20 or on the ear strap 21, etc. For example, the sensor device may be provided on the ear strap 21 that comes into contact with the user's skin, emit light onto the user's body, and sense the light reflected from the user's body to output a digital signal. The mobile device 20 can use the digital signal to determine the user's biometric information and provide various applications that utilize this biometric information.

[0016] Figure 3 is a simplified diagram showing a sensor device according to one embodiment of the present invention.

[0017] Referring to Figure 3, a sensor device 30 according to one embodiment of the present invention operates in close proximity to the user's body 40 and may include a light-emitting unit 31 and a sensor array 32. The sensor array 32 includes a plurality of sensing elements 33, and for example, each of the plurality of sensing elements may include a photodiode. For example, the sensor device 30 may be a PPG (Photoplethysmography) sensor or a spectrometer as a multi-channel optical sensor including a plurality of photodiodes.

[0018] As shown in Figure 3, the light-emitting unit 31 can emit light toward the user's body 40. The light-emitting unit 31 includes at least one light source, and depending on the embodiment, the light source can emit light in a specific wavelength range. For example, the wavelength range of the light emitted by the light source can vary depending on the biological information to be determined using the sensor device 30.

[0019] For example, when attempting to determine the heart rate from the user's body 40, the light-emitting unit 31 may include a light source that emits light in the green wavelength band. In another example, when attempting to determine the blood oxygen saturation from the user's body 40, the light-emitting unit 31 may include a light source that emits light in the red wavelength band and the infrared wavelength band. The light-emitting unit 31 can be composed of multiple light sources that emit light in different wavelength bands, and at least one of the light sources can be operated according to the biological information to be determined to acquire a signal from the sensor array 32.

[0020] In one embodiment, the sensor array 32 may include a plurality of sensing elements 33 arranged in a matrix configuration. However, the arrangement of the sensing elements 33 can be varied in various ways depending on the embodiment. Each of the sensing elements 33 includes a photodiode, which can generate an electric current signal in response to light. A signal processing module included in the sensor device 30 processes the electric current signal to generate a digital signal, and the processor of a mobile device equipped with the sensor device 30 can use the digital signal to determine biological information.

[0021] Figure 4 is a diagram illustrating the operation of a sensor device according to one embodiment of the present invention.

[0022] Referring to Figure 4, the sensor array 50 of the sensor device according to one embodiment of the present invention may include a filter layer 51 and a photodiode layer 52. The filter layer 51 may include a plurality of color filters, and the photodiode layer 52 may include a plurality of photodiodes.

[0023] Light emitted from the light-emitting part and reflected from the user's body, such as blood vessels inside the body, can appear in all wavelength bands, as shown in the first graph 60 in Figure 4. However, as described above, depending on the type of biological information to be determined using the sensor device, light in a specific wavelength band can be selectively used, and for this purpose, the sensor array 50 can include a filter layer 51. The filter layer 51 can selectively transmit light in a specific wavelength band to the photodiode layer 52, as shown in the second graph 70. Therefore, a sensor device including the sensor array 50 according to one embodiment shown in Figure 4 can operate as a multi-wavelength PPG sensor.

[0024] Therefore, the sensitivity of the sensor device can be improved, and by configuring the light-emitting section with a light source that emits light in all wavelength bands and selectively injecting light in the required wavelength bands into the photodiode via the filter layer 51, it is possible to realize a sensor device that can determine various biological information with a single light source. For this reason, at least some of the multiple color filters can pass light in wavelength bands that are different from each other.

[0025] For example, among multiple color filters, the first color filter 51A can allow only light in the green wavelength band to pass through. The first color filter 51A can have a structure in which an infrared blocking filter and a green color filter that allows only light in the green wavelength band to pass through are stacked. Therefore, of the light emitted from the light source of the light-emitting part and reflected by blood vessels, etc., only light in the green wavelength band can be incident on the first photodiode 52A below the first color filter 51A. The processor of a mobile device equipped with a sensor device can use the current signal output by the first photodiode 52A to determine the user's heart rate, pulse, etc.

[0026] On the other hand, among the multiple color filters, the second color filter 51B can pass only light in the red wavelength band, and the third color filter 51C can pass only light in the infrared wavelength band. Therefore, the red wavelength band light emitted from the light source of the light-emitting unit and reflected by blood vessels etc. can be incident on the second photodiode 52B below the second color filter 51B, and the infrared wavelength band light can be incident on the third photodiode 52C below the third color filter 51C. The processor of the mobile device equipped with the sensor device can determine the user's blood oxygen saturation level using the current signals output by the second photodiode 52B and the third photodiode 52C.

[0027] To determine various biological information with a single sensor device, a sensor array 50 can be configured with a filter layer 51 and a photodiode layer 52, as explained with reference to Figure 4. In order to process the current signal output by the sensor array 50 according to one embodiment shown in Figure 4 and determine the desired biological information, the photodiodes included in the photodiode layer 52 can be connected via multiple channels to a signal processing module that processes the current signal. The signal processing module can be configured to independently process the current signals received via multiple channels and generate a digital signal, but in this case, the area occupied by the signal processing module and the consumable electrodes of the signal processing module may increase.

[0028] One embodiment of the present invention proposes a sensor device capable of processing current signals generated by a sensor array 50 with a single signal processing module. The sensor device according to one embodiment of the present invention may include an encoder connected between the input terminal of the signal processing module and the sensor array 50, and a decoder connected to the output terminal of the signal processing module. The encoder can encode current signals received via multiple channels to generate analog signals and sequentially input these analog signals to the signal processing module. When the signal processing module sequentially processes the analog signals and outputs digital signals, the decoder can use the digital signals to generate data signals corresponding to the multiple channels. Therefore, a single signal processing module can process current signals received via multiple channels, thereby reducing the area and power consumption of the sensor device. Furthermore, the impact of noise generated during the process of the signal processing module converting current signals into data signals can be reduced.

[0029] Figure 5 is a simplified diagram showing a sensor device according to one embodiment of the present invention.

[0030] Referring to Figure 5, a sensor device 100 according to one embodiment of the present invention may include a substrate 101, a light source 110 mounted on the first surface of the substrate 101, a plurality of photodiodes 120 mounted on the first surface together with the light source 110, and a signal processing device 130. In some embodiments, the signal processing device 130 may also be mounted on a second surface of the substrate 101 facing the first surface. The substrate 101 may include a connector 140, via which the processor of a mobile device on which the sensor device 100 is mounted and the sensor device 100 can be electrically connected to each other.

[0031] In one embodiment shown in Figure 5, the photodiodes 120 can be dispersed around the light source 110. However, this is only one embodiment, and the number and position of the photodiodes 120 can be varied in various ways. On the other hand, as described above, a color filter that selectively transmits light in a specific wavelength band can also be placed above the photodiodes 120.

[0032] Referring to Figure 5, the sensor device 100 includes four photodiodes 120, and the signal processing device 130 can receive current signals from the photodiodes 120 via four channels. The signal processing device 130 may include an encoder that receives current signals via four channels, a signal processing module that sequentially processes the analog signals output by the encoders to output digital signals, and a decoder that uses the digital signals output by the signal processing module to reconstruct data signals corresponding to the four channels.

[0033] Figure 6 is a simplified block diagram showing a mobile device according to one embodiment of the present invention.

[0034] Referring to Figure 6, a mobile device 200 according to one embodiment of the present invention may include a sensor device 210 and a processor 220. The processor 220 is a semiconductor device that controls the overall operation of the mobile device 200, controls the operation of the sensor device 210, and can determine information related to an object OBJ using the digital signals output by the sensor device 210. For example, if the object OBJ is a human body, the processor can determine information such as heart rate, blood oxygen saturation, and blood pressure, and execute various applications based on this information.

[0035] The sensor device 210 may include a light source 211, a light source driver 212, a sensor array 213, a signal processing device 214, and the like. The light source 211 can emit light toward the object OBJ in response to a light control signal output by the light source driver 212. For example, the light control signal output by the light source driver 212 to the light source 211 can be a PWM (Pulse Width Modulation) signal. Therefore, the light source 211 can repeatedly turn on and off while the sensor device 210 is activated and operating.

[0036] The sensor array 213 includes a plurality of photodiodes PD, and depending on the embodiment, it may further include a color filter that selectively incidents light of a predetermined wavelength band onto the photodiodes PD. The photodiodes PD can generate a current signal in response to light emitted by the light source 211 and reflected by the object OBJ. However, depending on the embodiment, the light source 211 may be omitted, in which case the photodiodes PD can generate a current signal in response to light incident from the object OBJ or the like.

[0037] The signal processing device 214 can convert the current signal into a digital signal and output it to the processor 220. While the sensor device 210 is activated and operating, the light source 211 can repeatedly turn on and off at a predetermined frequency, so the signal processing device 214 can synchronize with the light source driver 212 to acquire a current signal from the photodiode PD during the time the light source 211 is turned on.

[0038] Figure 7 is a simplified block diagram showing a sensor device according to one embodiment of the present invention.

[0039] Referring to Figure 7, a sensor device 300 according to one embodiment of the present invention may include a plurality of photodiodes PD1 to PD4, a signal processing module 310, an encoder 320, and a decoder 330. The photodiodes PD1 to PD4 can generate current signals I1 to I4 in response to light incident from an external source. For example, the photodiodes PD1 to PD4 can generate current signals I1 to I4 in response to light emitted from another light source and reflected by an object, the object may be a part of the user's body. The current signals I1 to I4 can be input to the encoder 320 via a plurality of analog channels ACH1 to ACH4.

[0040] The encoder 320 can be connected to photodiodes PD1 to PD4 via analog channels ACH1 to ACH4 and to the input terminal of the signal processing module 310 via one input channel ICH. The encoder 320 can encode current signals I1 to I4 to generate analog signals and input these analog signals sequentially to the signal processing module 310 via input channel ICH. Therefore, the signal processing module 310 can receive the analog signals sequentially via input channel ICH. Each of the analog signals encoded by the encoder 320 can be a signal composed of current signals I1 to I4 as components, or a signal obtained by encoding current signals I1 to I4 using a predetermined orthogonal code.

[0041] The signal processing module 310 can process sequentially input analog signals to generate digital signals. For example, the encoder 320 can generate four analog signals using four current signals I1 to I4, and the signal processing module 310 can convert these four analog signals into a digital domain to output four digital signals. The signal processing module 310 can sequentially output the four digital signals to the decoder 330 via an output channel OCH connected to its output terminal.

[0042] The decoder 330 can generate data signals DATA1 to DATA4 using digital signals. Data signals DATA1 to DATA4 are output via multiple digital channels DCH1 to DCH4, and can be signals obtained by converting current signals I1 to I4 into digital domains, respectively. For example, the first data signal DATA1 can be a signal obtained by converting the first current signal I1 into a digital domain, and the second data signal DATA2 can be a signal obtained by converting the second current signal I2 into a digital domain.

[0043] The decoder 330 can generate data signals DATA1 to DATA4 by referring to the orthogonal codes used by the encoder 320 when encoding current signals I1 to I4 to generate analog signals. For example, the decoder 330 can reconstruct data signals DATA1 to DATA4 from the digital signal using the inverse of the orthogonal matrix corresponding to the orthogonal code.

[0044] The signal processing module 310 can be an analog-front-end module. The signal processing module 310 may include a current-voltage converter that converts the analog signals generated from current signals I1-I4 into voltages, an amplifier that amplifies the analog signals, and an analog-to-digital converter (ADC). Further details are provided below with reference to Figure 8.

[0045] Figure 8 is a simplified diagram showing a signal processing module included in a sensor device according to one embodiment of the present invention.

[0046] Referring to Figure 8, a signal processing module 310 according to one embodiment of the present invention may include a current-to-voltage converter 311, an amplifier 312, and an analog-to-digital converter 313. The current-to-voltage converter 311 is a circuit that converts analog signals received sequentially through the input channel ICH into voltages, and may include, for example, an operational amplifier and a feedback resistor. The output of the current-to-voltage converter 311 is transmitted to the amplifier 312, which may include a programmable gain amplifier.

[0047] The analog-to-digital converter 313 can convert the signal output by the amplifier 312 into a digital domain to generate a digital signal, which it can then send to the output channel OCH. In the operation of the signal processing module 310, analog signals are sequentially input by an encoder connected to the input terminal of the signal processing module 310, and the analog-to-digital converter 313 can sequentially output digital signals corresponding to the analog signals.

[0048] Figure 9 is a simplified diagram showing a sensor device according to one embodiment of the present invention.

[0049] Referring to Figure 9, a sensor device 400 according to one embodiment of the present invention may include a signal processing module 410, an encoder 420, and a decoder 430. The encoder 420 is connected to a plurality of photodiodes PD1 to PD4 and can encode current signals I1 to I4 to generate an analog signal AIN. The analog signal AIN can be sequentially input to the signal processing module 410.

[0050] The signal processing module 410 can convert the analog signal AIN to digital and generate the digital signal DOUT. The digital signal DOUT is input to the decoder 430, which can use the digital signal DOUT to generate data signals DATA1 to DATA4. For example, the data signals DATA1 to DATA4 can correspond to the current signals I1 to I4 generated by the photodiodes PD1 to PD4, respectively.

[0051] In one embodiment shown in Figure 9, the encoder 420 may include a plurality of multipliers 421-424 and an adder 425. Multipliers 421-424 each receive encoding coefficients ENC1-ENC4 as inputs and can output the result of multiplying current signals I1-I4 by the encoding coefficients ENC1-ENC4. The encoding coefficients ENC1-ENC4 can be non-zero. The adder 425 can generate an analog signal AIN by adding the multiplied signals of the encoding coefficients ENC1-ENC4 and the current signals I1-I4. The encoding coefficients ENC1-ENC4 can be determined by an orthogonal code used by the encoder 420 when encoding the current signals I1-I4 to generate the analog signal AIN.

[0052] As an example, the values ​​of encoding coefficients ENC1 to ENC4 can change while multiple photodiodes PD1 to PD4 are outputting current signals I1 to I4. If there are four photodiodes PD1 to PD4, the encoder 420 divides the time during which the current signals I1 to I4 are output into four unit time intervals, and sets at least one of the encoding coefficients ENC1 to ENC4 to a different value within each unit time interval. The encoding coefficients ENC1 to ENC4 and the corresponding operation of the encoder 420 will be described later with reference to Figure 10.

[0053] Referring to Figure 9, the decoder 430 can include multiple multipliers 431-434 and multiple accumulators 435-438. For example, each digital channel that outputs data signals DATA1-DATA4 can be assigned one of the multipliers 431-434 and one of the accumulators 435-438.

[0054] Multipliers 431-434 receive decoding coefficients DEC1-DEC4 as inputs and can multiply each of the digital signals DOUT, which are output sequentially, by the decoding coefficients DEC1-DEC4. Accumulators 435-438 can generate data signals DATA1-DATA4 by sequentially accumulating and adding the digital signals DOUT multiplied by the decoding coefficients DEC1-DEC4. The decoding coefficients DEC1-DEC4 can be determined by the inverse matrix of the orthogonal code used by encoder 420. In one embodiment, the absolute value of each decoding coefficient DEC1-DEC4 may be smaller than the absolute value of each encoding coefficient ENC1-ENC4.

[0055] The operation of the sensor device 400 will be explained in more detail below with reference to Figures 10, 11a, and 11b.

[0056] Figure 10 is a timing diagram provided to illustrate the operation of a sensor device according to one embodiment of the present invention. Figures 11a and 11b are drawings provided to illustrate the operation of a sensor device according to one embodiment of the present invention.

[0057] First, referring to Figure 10, during the light emission time TON when the light source is turned on by the light control signal, the photodiodes PD1 to PD4 can output current signals I1 to I4. The sensor device 400 can divide the light emission time TON into multiple unit times T1 to T4, and the encoder 420 can adjust the encoding coefficients ENC1 to ENC4 for each of the unit times T1 to T4 to generate the analog signal AIN.

[0058] For example, during the first unit time T1, the encoding coefficients ENC1 to ENC4 can be determined to be [+1, -1, -1, -1]. Therefore, the first analog signal AIN1 input to the signal processing module 410 during the first unit time T1 can be determined to be [I1-I2-I3-I4]. During the next second unit time T2, the encoding coefficients ENC1 to ENC4 are determined to be [-1, +1, -1, -1], and the signal processing module 410 can receive the second analog signal AIN2 defined as [-I1+I2-I3-I4]. Similarly, the third analog signal AIN3 input to the signal processing module 410 during the third unit time T3 can be represented as [-I1-I2+I3-I4], and the fourth analog signal AIN4 input to the signal processing module 410 during the fourth unit time T4 can be represented as [-I1-I2-I3+I4].

[0059] The signal processing module 410 can sequentially convert the first to fourth analog signals AIN1 to AIN4 into digital domains and output the first to fourth digital signals DOUT1 to DOUT4. The output timing of the first to fourth digital signals DOUT1 to DOUT4 can be determined as shown in Figure 10 by the time it takes for the signal processing module 410 to convert each of the first to fourth analog signals AIN1 to AIN4 into a digital domain. However, the delay time, which is the difference between the input time of the first to fourth analog signals AIN1 to AIN4 and the output time of the first to fourth digital signals DOUT1 to DOUT4, can be varied in various ways depending on the configuration of the signal processing module 410.

[0060] The encoding code used by encoder 420 to encode current signals I1 to I4 and generate the analog signal AIN can be a code generated based on an orthogonal code and can be represented by an orthogonal matrix. As an example, in one embodiment described with reference to Figure 10, the encoding code can be represented as shown in mathematical equation 1 below. The rows of the encoding code correspond to unit times T1 to T4, and the columns correspond to encoding coefficients ENC1 to ENC4, respectively. As shown in mathematical equation 1, the encoding coefficients ENC1 to ENC4 can be non-zero.

[0061]

number

[0062] As described above, the decoding coefficients DEC1 to DEC4 used by the decoder 430 to reconstruct data signals DATA1 to DATA4 from the digital signal DOUT can be determined by a decoding code represented by the inverse of an orthogonal matrix. As an example, the decoding code corresponding to the encoding code shown in mathematical formula 1 can be expressed as shown in mathematical formula 2 below. Each row in the decoding code can correspond to a decoding coefficient DEC1 to DEC4. As shown in mathematical formulas 1 and 2, the absolute value of each decoding coefficient DEC1 to DEC4 may be smaller than the absolute value of each encoding coefficient ENC1 to ENC4.

[0063]

number

[0064] The operation of the encoder 420 and decoder 430 will be described in more detail below with reference to Figures 11a and 11b.

[0065] First, Figure 11a can be seen as a diagram illustrating the operation of the encoder 420. Referring to Figure 11a, the current signals I1 to I4 generated by the photodiodes PD1 to PD4 are represented as a matrix, and the first to fourth analog signals AIN1 to AIN4 can be generated as a result of calculations between the encoding code and the current signals I1 to I4. The first to fourth analog signals AIN1 to AIN4 are input sequentially to the signal processing module 410, which converts each of the first to fourth analog signals AIN1 to AIN4 into digital and outputs the first to fourth digital signals DOUT1 to DOUT4 in sequence.

[0066] In one embodiment, noise may be generated during the operation of the signal processing module 410 to convert the first to fourth analog signals AIN1 to AIN4 to digital. Therefore, each of the first to fourth digital signals DOUT1 to DOUT4 has a predetermined noise component V N It may include. In one embodiment shown in Figure 11a, each of the first to fourth digital signals DOUT1 to DOUT4 has a noise component V of the same magnitude. N Although it was indicated that it includes, in the example, at least a portion of the first to fourth digital signals DOUT1 to DOUT4 contains noise component V N Their sizes may vary.

[0067] Next, Figure 11b is a diagram illustrating the operation of the decoder 430. Referring to Figure 11b, the operation of the decoder 430 can be represented by a decoding code. First, while the signal processing module 410 outputs the first digital signal DOUT1, the digital coefficients DEC1 to DEC4 can be defined as [+1 / 4, -1 / 4, -1 / 4, -1 / 4]. Therefore, the first accumulator 435 can be input with +1 / 4 × DOUT1, and the second to fourth accumulators 436 to 438 can be input with -1 / 4 × DOUT1, respectively.

[0068] Next, while the signal processing module 410 outputs the second digital signal DOUT2, the digital coefficients DEC1 to DEC4 can be determined to be [-1 / 4, +1 / 4, -1 / 4, -1 / 4]. Therefore, the second accumulator 436 can be input with +1 / 4 × DOUT2, and the first, third, and fourth accumulators 435, 437, and 438 can be input with -1 / 4 × DOUT2, respectively. While the signal processing module 410 outputs the third digital signal DOUT3, the digital coefficients DEC1 to DEC4 are determined to be [-1 / 4, -1 / 4, +1 / 4, -1 / 4], the third accumulator 437 can be input with +1 / 4 × DOUT3, and the first, second, and fourth accumulators 435, 436, and 438 can be input with -1 / 4 × DOUT3, respectively. Finally, while the signal processing module 410 outputs the fourth digital signal DOUT4, the digital coefficients DEC1 to DEC4 are determined to be [-1 / 4, -1 / 4, -1 / 4, +1 / 4], and the fourth cumulative unit 438 can be input with +1 / 4 × DOUT4, while the first to third cumulative units 435 to 437 can be input with -1 / 4 × DOUT4, respectively.

[0069] After the signal processing module 410 outputs up to the fourth digital signal DOUT4, the signals accumulated and added to each of the accumulators 435 to 438 can be expressed as shown in mathematical formula 3 below.

[0070]

number

[0071] The digital signals DOUT1 to DOUT4 output by the signal processing module 410 contain noise component V. NIt includes and can be defined as described with reference to Figure 11a. Applying the digital signals DOUT1~DOUT4 described with reference to Figure 11a to mathematical formula 3, the data signals DATA1~DATA4 output by the accumulators 435~438 can be defined as shown in Figure 11b. In other words, each of the data signals DATA1~DATA4 consists of data obtained by converting each of the current signals I1~I4 into the digital domain and the noise component (0.5V) that has been averaged and reduced by the operation of the decoder 430. N ) can include

[0072] In one embodiment of the present invention, an encoder 420 and a decoder 430 are connected to the input and output terminals of a signal processing module 410, respectively. The encoder 420 can sequentially input analog signals AIN, which are encoded from current signals I1 to I4 received via multiple analog channels, to the signal processing module 410. The signal processing module 410 converts the analog signals AIN into digital signals DOUT and outputs them sequentially to the decoder 430, and in this process a predetermined noise component V N This can be reflected in each of the digital signals DOUT. In the process in which the decoder 430 uses the digital signal DOUT to reconstruct the data signals DATA1 to DATA4 corresponding to the current signals I1 to I4, the noise component V N This can be offset and / or reduced. Therefore, a sensor device 400 with excellent noise-to-signal ratio characteristics can be realized.

[0073] The configuration of the encoding and decoding codes for the operation of the encoder 420 and decoder 430 is not limited, as described with reference to Figures 10, 11a, and 11b. The encoding coefficients ENC1 to ENC4 and decoding coefficients DEC1 to DEC4 that define the encoding and decoding codes can be freely selected under the condition that the characteristics of orthogonal codes are satisfied. On the other hand, the size of the matrices representing the encoding and decoding codes can be determined according to the number of sensing elements, such as photodiodes PD1 to PD4, connected to the signal processing module 410.

[0074] Figures 12a and 12b are drawings provided to illustrate the operation of a sensor device according to one embodiment of the present invention.

[0075] In one embodiment shown in Figures 12a and 12b, the sensor device may include eight sensing elements. Therefore, as shown in Figure 12a, the encoding code can be represented by an 8x8 matrix. In one embodiment shown in Figure 12a, the diagonal components of the encoding code can all be +1, and the remaining components can all be -1. However, this is just one embodiment, and the components of the encoding code can be transformed in various ways while satisfying the characteristics of an orthogonal code.

[0076] The sensor device can divide the emission time of the light source into eight unit time intervals T1 to T8. In each of the unit time intervals T1 to T8, at least some of the encoding coefficients ENC1 to ENC8 can have different values ​​from each other, and the signal processing module can receive the eight analog signals AIN1 to AIN8 generated by the encoder sequentially during the emission time.

[0077] Figure 12b can be a diagram illustrating the operation of the decoder. Referring to Figure 12b, the decoding code is the inverse matrix of the encoding code and can be represented as an 8x8 matrix. The decoding code allows the signal processing module to convert each of the analog signals AIN1 to AIN8 into digital signals DOUT1 to DOUT8, which are then restored to data signals DATA1 to DATA8. As an example, each of the data signals DATA1 to DATA8 consists of data obtained by converting each of the current signals I1 to I8 into a digital domain, and the noise component (0.75V) that has been averaged and reduced by the decoder. N ) can be included.

[0078] Therefore, the noise characteristics of the sensor device can be improved compared to when encoders and decoders are not applied. In addition, since current signals output by multiple sensing elements can be processed by a single signal processing module, the integration density of the sensor device can be increased and power consumption can be reduced.

[0079] Figure 13 is a graph provided to illustrate the operation of a sensor device according to one embodiment of the present invention.

[0080] Figure 13 shows that the signal-to-noise ratio (SNR) of a sensor device can be increased by increasing the number of photodiodes included in the sensor device. For example, compared to the case where the signal processing module generates a data signal using the current signal generated by one photodiode, the signal-to-noise ratio can be improved by approximately 6 dB when using the current signal generated by four photodiodes. Furthermore, when generating a data signal using the current signal generated by eight photodiodes, the signal-to-noise ratio can be improved by approximately 9 dB.

[0081] As a result, by increasing the number of photodiodes, which generate current signals in response to light emitted by a light source and reflected from the user's body, the noise-to-signal ratio can be improved, thereby improving the performance of the sensor device. However, increasing the number of photodiodes may increase the number of signal processing modules and channels connecting the photodiodes, which may increase the power consumption of the signal processing modules and the circuit area they occupy.

[0082] In one embodiment of the present invention, the above-mentioned problems can be solved by connecting an encoder and a decoder to the input and output terminals of a signal processing module, respectively. The current signal generated by the photodiode is encoded into an analog signal by the encoder and sequentially input to the signal processing module, which can then sequentially output digital signals. The decoder can then use the sequentially output digital signals to reconstruct the data signal. Therefore, since a single signal processing module can process the current signals of photodiodes connected to multiple channels, the power consumption and circuit area of ​​the sensor device can be reduced, and the production cost of the sensor device can also be lowered.

[0083] However, depending on the embodiment, the sensor device may include two or more signal processing modules. For example, if N photodiodes are connected via N channels, the photodiodes can be divided into N / 2 units and distributed to two signal processing modules. In this case, the operating speed of the sensor device can be improved by reducing the number of photodiodes connected to each signal processing module and the number of current signals that each signal processing module must process.

[0084] Figure 14 is a simplified diagram showing a sensor device according to one embodiment of the present invention.

[0085] In one embodiment shown in Figure 14, the sensor device 500 may include a plurality of photodiodes PD1 to PD4, a signal processing module 510, an encoder 520, and a decoder 530. As described above, the number of photodiodes PD1 to PD4 can be varied in various ways.

[0086] The encoder 520 includes multiple switches SW1 and SW2, and each of the photodiodes PD1 to PD4 can be connected to a pair of switches SW1 and SW2. The on / off state of a pair of switches SW1 and SW2 can be determined by encoding coefficients ENC1 to ENC4. For example, a pair of switches SW1 and SW2 may not be turned on simultaneously. For instance, when the first switch SW1 of the pair of switches SW1 and SW2 is turned on, the second switch SW2 may be turned off, and when the second switch SW2 is turned on, the first switch SW1 may be turned off.

[0087] In one embodiment shown in Figure 14, the signal processing module 510 can receive analog signals in a differential signaling manner via a positive input terminal 511 and a negative input terminal 512. The first switch SW1 can be connected to the positive input terminal 511, and the second switch SW2 can be connected to the negative input terminal 512. The operation of the encoder 520 is similar to that described earlier with reference to Figures 10 and 11a.

[0088] For example, during the first unit time, the first switch SW1 connected to the first photodiode PD1 may be turned on by the first encoding coefficient ENC1, and the second switch SW2 connected to the second to fourth photodiodes PD2 to PD4 may be turned on by the second to fourth encoding coefficients ENC2 to ENC4. Therefore, during the first unit time, the analog signal AIN input to the signal processing module 510 can be defined as [I1-I2-I3-I4]. Similarly, during the second unit time, the second switch SW2 connected to the second photodiode PD2 may be turned on, and the first switch SW1 connected to the first, third, and fourth photodiodes PD1, PD3, and PD4 may be turned on. Therefore, the encoder 520 may operate in the same manner as described earlier with reference to Figures 10 and 11a. The operation of the decoder 530 is also similar to that described earlier with reference to Figure 11b.

[0089] Figures 15 to 17 are comparative examples illustrating a sensor device according to one embodiment of the present invention.

[0090] Referring to Figure 15, which shows a sensor device 600 related to a comparative example, the signal processing module 610 can convert the analog signal AIN into a digital signal DOUT. Multiple photodiodes PD1 to PD4 can be connected to the input terminal of the signal processing module 610 via multiple switches SW1 to SW4.

[0091] Figure 16 is a timing diagram illustrating the operation of the sensor device 600. Referring to Figure 16, the first to fourth switches SW1 to SW4 can be turned on sequentially during each of the first to fourth time periods T1 to T4. Therefore, the first to fourth current signals I1 to I4 are input sequentially to the signal processing module 610, and the signal processing module 610 can sequentially output digital signals DOUT1 to DOUT4 corresponding to the first to fourth current signals I1 to I4.

[0092] The operation of the sensor device 600 can be represented by the matrix shown in FIG. 17. Referring to FIG. 17, the operation of the first to fourth switches SW1 to SW4 can be expressed by a matrix in which all diagonal components are 1 and the remaining components are all 0 during the first to fourth time periods T1 to T4. During the first time period T1, only the first switch SW1 is turned on, and the first current signal I1 is input to the signal processing module 610, and the signal processing module 610 can digitally convert the first current signal I1 to generate the first digital signal DOUT1. Similar operations as described above can also be executed at each of the second to fourth time periods T2 to T4.

[0093] Therefore, the noise component V generated by the operation of the signal processing module 610 may be directly reflected in the first to fourth digital signals DOUT1 to DOUT4. N Different from the present application, in a comparative example where an encoder and a decoder are not connected to the input end and the output end of the signal processing module 610, the noise component V generated by the operation of the signal processing module 610 N cannot be expected to have the effect of being averaged and reduced. Referring to FIGS. 11a and 11b, which illustrate an embodiment of the present invention including four photodiodes PD1 to PD4, in an embodiment of the present invention, the noise component V N can be averaged by the decoder and reduced by half when compared with the comparative example. Therefore, a sensor device with excellent noise ratio for signals and improved noise characteristics can be realized.

[0094] FIG. 18 is a block diagram schematically showing a mobile device according to an embodiment of the present invention.

[0095] Referring to Figure 18, the mobile device 1000 may include a camera 1100, a display 1200, an audio processing unit 1300, a modem 1400, DRAMs 1500a and 1500b, flash memory devices 1600a and 1600b, input / output devices 1700a and 1700b, a sensor device 1800, and an application processor (AP) 1900.

[0096] Mobile device 1000 can be implemented as a laptop computer, portable terminal, smartphone, tablet PC, wearable device, healthcare device, or IoT (Internet-of-Things) device. Alternatively, mobile device 1000 can be implemented as a server or personal computer.

[0097] Various components included in the mobile device 1000 can operate in synchronization with a predetermined clock. For example, the display 1200 can display the screen at a predetermined rate, and the DRAM 1500a, 1500b and flash memory devices 1600a, 1600b can also operate at a predetermined clock to store and read data at a predetermined speed, or to transmit and receive data with other external devices. The input / output devices 1700a, 1700b and the application processor 1900 can also operate at a predetermined clock.

[0098] Camera 1100 can capture still images and videos under user control. Mobile device 1000 can use the still images / videos captured by camera 1100 to acquire specific information, or convert the still images / videos into other forms of data such as text and save them. Camera 1100 can include multiple cameras having different angles of view, aperture values, etc. Furthermore, in addition to cameras that capture a subject and generate an actual image, camera 1100 can further include cameras that use depth information of the subject and / or background to generate a depth image.

[0099] The display 1200 can also be used as an input device for the mobile device 1000 by providing touchscreen functionality. Furthermore, the display 1200 can be provided in conjunction with a fingerprint sensor or the like to provide security features for the mobile device 1000. The audio processing unit 1300 can process audio data stored in the flash memory devices 1600a and 1600b, as well as audio data contained in content received from external sources via the modem 1400 or input / output devices 1700a and 1700b.

[0100] The modem 1400 modulates and transmits signals for wired / wireless data transmission and reception, while also demodulating signals received from an external source to restore the original signal. Input / output devices 1700a and 1700b are devices that provide digital input and output, and may include a port that can be connected to an external recording medium, input devices such as a touchscreen or mechanical button keys, and output devices that can output vibrations in a haptic manner or the like.

[0101] The sensor device 1800 may include multiple sensors that collect various information from the outside. In one embodiment, the sensor device 1800 may include an illuminance sensor that senses the brightness of light, a gyro sensor that senses the movement of the mobile device 1000, and a multi-channel optical sensor for acquiring biometric information from the body of a user in contact with and / or close to the mobile device 1000. For example, the multi-channel optical sensor may include a PPG (Photoplethysmography) sensor and / or a spectrometer.

[0102] The multi-channel optical sensor included in the sensor device 1800 may include a light source, a sensor array, and a signal processing module that processes the signals generated by the sensor array. As an example, the multi-channel optical sensor can be realized by the embodiment described earlier with reference to Figures 3 to 14. The AP1900 can use the data signals output by the multi-channel optical sensor to measure biometric information about the user's body, such as pulse rate, heart rate, blood oxygen saturation, and blood pressure, and execute an application appropriate to that information.

[0103] The AP1900 can control the overall operation of the mobile device 1000. Specifically, the AP1900 can control the display 1200 so that some of the content stored in the flash memory devices 1600a and 1600b is displayed on the screen. In addition, when the AP1900 receives user input via input / output devices 1700a, 1700b, etc., it can perform control operations corresponding to the user input.

[0104] In one embodiment, AP1900 may also include an accelerator block 1920, which is a dedicated circuit for AI data computation. Alternatively, depending on the embodiment, a separate accelerator chip may be provided separately from AP1900, and DRAM 1500b may be further coupled to the accelerator block 1920 or accelerator chip. The accelerator block 1920 may include functional blocks that specialize in performing specific functions of AP1900, such as a GPU (Graphics Processing Unit) that specializes in graphics data processing, an NPU (Neural Processing Unit) that specializes in AI computation and inference, and a DPU (Data Processing Unit) that specializes in data transfer.

[0105] The present invention is not limited by the embodiments described above or the accompanying drawings, but is limited by the claims provided. Therefore, various forms of substitution, modification, and alteration are possible by persons with ordinary skill in the art, without departing from the technical idea of ​​the present invention as described in the claims, and these also fall within the scope of the present invention. [Explanation of Symbols]

[0106] 10, 20, 200 mobile devices 40, 100, 210, 300, 400, 500 sensor devices 310, 410, 510 Signal Processing Modules 320, 420, 520 encoders 330, 430, 530 decoders

Claims

1. A sensor array having multiple photodiodes that generate an electric current signal in response to light, An encoder that encodes the current signal to generate multiple analog signals and outputs the multiple analog signals sequentially, A signal processing module that processes the plurality of analog signals received from the encoder to generate a digital signal, The system includes a decoder that decodes the digital signal received from the signal processing module and generates a plurality of data signals corresponding to the current signal, The encoder encodes the current signal using a predetermined orthogonal code to generate the analog signal. The decoder decodes the digital signal using the inverse matrix of the orthogonal code to generate the data signal. Sensor device.

2. The sensor device according to claim 1, wherein the data signal includes biological information for generating at least one of heart rate, blood oxygen saturation, and blood pressure.

3. The sensor device according to claim 1 or 2, wherein the sensor array generates the current signal in response to light reflected from blood vessels in the body.

4. The sensor device according to claim 1, wherein the number of the plurality of photodiodes is N (where N is a natural number of 2 or more), and the orthogonal code is defined as an N × N matrix.

5. The sensor device according to claim 1, wherein the encoder is connected between the plurality of photodiodes and the input terminal of the signal processing module and includes a multiplier that multiplies each of the analog signals by a predetermined coefficient.

6. The signal processing module includes a positive input terminal and a negative input terminal, The encoder includes a plurality of positive switches connected between the plurality of photodiodes and the positive input terminal, and a plurality of negative switches connected between the plurality of photodiodes and the negative input terminal. The sensor device according to claim 1.

7. The sensor device according to claim 6, wherein when the positive switch connected to one of the plurality of photodiodes is turned on, the negative switches connected to the remaining photodiodes are turned on.

8. The sensor device according to claim 7, wherein the plurality of positive switches are turned on sequentially while the plurality of photodiodes output the analog signal.

9. It further includes a light-emitting part that emits light, The light-emitting time during which the light-emitting unit is turned on includes a plurality of unit times, The encoder generates the analog signals sequentially by multiplying at least a portion of the current signals by different coefficients and adding them together in each of the plurality of unit time periods. The sensor device according to any one of claims 1 to 8.

10. The sensor device according to claim 9, wherein the length of each of the plurality of unit times corresponds to the time it takes for the signal processing module to convert each of the analog signals into a digital domain.

11. Multiple photodiodes that generate an electric current signal in response to light, An encoder is provided, which is connected to the photodiode via multiple analog channels and includes a multiplier and an adder that operate according to a predetermined orthogonal code, and sequentially outputs multiple analog signals encoded from the current signal via one input channel. A signal processing module including an input terminal connected to the input channel and outputting a plurality of digital signals corresponding to the analog signal via an output terminal, A decoder connected to the output terminal, which outputs multiple data signals obtained by decoding the digital signal using the inverse matrix of the orthogonal matrix corresponding to the orthogonal code, via multiple digital channels, A processor that generates information corresponding to the current signal using the data signal, Sensor device.

12. The sensor device according to claim 11, wherein the encoder generates the analog signal by multiplying the current signal by an encoding coefficient determined from the orthogonal code and adding it.

13. The sensor device according to claim 12, wherein each of the encoding coefficients is not zero.

14. The sensor device according to claim 13, wherein one of the encoding coefficients is 1 and the remaining encoding coefficients are -1.

15. The sensor device according to any one of claims 12 to 14, wherein the decoder generates the data signal by multiplying the digital signal by a decoding coefficient determined from the orthogonal code and adding it.

16. The sensor device according to claim 15, wherein the absolute value of each of the decoding coefficients is smaller than the absolute value of each of the encoding coefficients.

17. The sensor device according to claim 11, wherein the encoder includes a multiplier connected to each of the analog channels and an adder connected to the input channel.

18. The sensor device according to claim 11, wherein the decoder includes an adder, a subtractor, and an accumulator connected to each of the digital channels.

19. circuit board and Multiple photodiodes are mounted on the first surface of the substrate and generate an electric current signal in response to light incident from an object, A signal processing device is mounted on the first surface or the second surface of the substrate facing the first surface, and converts the current signal into a plurality of data signals. A processor that acquires biological information using the aforementioned data signals, The signal processing device sequentially converts a plurality of analog signals generated using the current signals received through a plurality of input channels into a plurality of digital signals, and generates the data signal using the digital signals. The signal processing device encodes the current signal using a predetermined orthogonal code to generate the analog signal. The signal processing device decodes the digital signal using the inverse matrix of the orthogonal code to generate the data signal. Mobile devices.

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