Sensor device and mobile device comprising the same

Abstract

A sensor device includes: a sensor array including a plurality of photodiodes configured to generate a current signal in response to light; an encoder configured to encode the current signal to generate a plurality of analog signals and sequentially output the plurality of analog signals; a signal processing module configured to process 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.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-015316, filed on February 3, 2021, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments relate to sensor devices and mobile devices that include them. Background Technology

[0004] Recently, sensor devices (such as biosensors) capable of collecting biometric information to provide useful services to users have tended to be installed in wearable and mobile devices. Sensor devices for collecting biometric information may include photodiodes that generate electrical charges in response to light, and signal processing may be performed on the charges generated by the photodiodes to determine biometric information. Summary of the Invention

[0005] The embodiments relate to a sensor device, including: a sensor array including a plurality of photodiodes configured to generate a current signal in response to light; an encoder configured to encode the current signal to generate a plurality of analog signals and sequentially output the plurality of analog signals; a signal processing module configured to process 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 signal.

[0006] The embodiments also relate to a sensor device, including: a plurality of photodiodes configured to generate a current signal in response to light; an encoder connected to the photodiodes via a plurality of analog channels, including a multiplier and an adder operating based on predetermined orthogonal codes, and configured to sequentially output a plurality of analog signals obtained by encoding the current signal to a single input channel; a signal processing module including an input terminal connected to the input channel, and configured to sequentially output a plurality of digital signals corresponding to the analog signals to an output terminal; a decoder connected to the output terminal, and configured to output a plurality of data signals obtained by decoding the digital signals according to the inverse matrix of the orthogonal matrix corresponding to the orthogonal codes to the plurality of digital channels; and a processor configured to use the data signals to generate information corresponding to the current signal.

[0007] The embodiments also relate to a mobile device, including: a substrate; a plurality of photodiodes mounted on the substrate and configured to generate a current signal in response to light incident from an object; a signal processing device mounted on the substrate and configured to convert the current signal into a plurality of data signals; and a processor configured to obtain biometric information using the data signals. The signal processing device is configured to sequentially convert a plurality of analog signals generated using current signals received through a plurality of input channels into a plurality of digital signals, and to generate data signals using the digital signals. Attached Figure Description

[0008] Features will become apparent to those skilled in the art from the detailed description of exemplary embodiments with reference to the accompanying drawings, wherein:

[0009] Figure 1 and 2 These are schematic diagrams of mobile devices according to example embodiments.

[0010] Figure 3 This is a schematic diagram of a sensor device according to an example embodiment.

[0011] Figure 4 This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0012] Figure 5 This is a schematic diagram of a sensor device according to an example embodiment.

[0013] Figure 6 This is a schematic block diagram of a mobile device according to an example embodiment.

[0014] Figure 7 This is a schematic block diagram of a sensor device according to an example embodiment.

[0015] Figure 8 This is a schematic diagram of a signal processing module included in a sensor device according to an example embodiment.

[0016] Figure 9 This is a schematic diagram of a sensor device according to an example embodiment.

[0017] Figure 10 This is a timing diagram illustrating the operation of a sensor device according to an example embodiment.

[0018] Figure 11A and 11B This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0019] Figure 12A and 12B This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0020] Figure 13 This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0021] Figure 14 This is a schematic diagram of a sensor device according to an example embodiment.

[0022] Figures 15 to 17 This is a diagram showing a comparative example of sensor devices.

[0023] Figure 18 This is a schematic block diagram of a mobile device according to an example embodiment. Detailed Implementation

[0024] Figure 1 and 2 These are schematic diagrams of mobile devices according to example embodiments.

[0025] refer to Figure 1 The mobile device 10 can be implemented as a watch-type wearable device. The mobile device 10 may include a housing or body 11 and a strap 12 to secure the mobile device 10 to a user's body, such as a wrist. A display for outputting images may be provided on the front surface of the body 11. Various application images, including time information, received message information, etc., can be displayed on the display. According to an example embodiment, at least one of the front surface and side surface of the body 11 may be provided with an input device 13 for receiving and processing user input. The input device 13 may include mechanical buttons or keys, a touch panel, etc.

[0026] Sensor device 14 can be disposed on the rear surface of body 11 facing the user's body. Sensor device 14 may include a light source emitting light toward the user's body (such as the user's wrist, to which body 11 may be secured by strap 12), at least one photodiode generating an electrical signal in response to light reflected from the user (e.g., the user's wrist), a signal processing module for processing the electrical signal, etc. For example, mobile device 10 can use the data signal output by sensor device 14 to determine biometric information, such as user heart rate, blood oxygen saturation, blood pressure, etc.

[0027] refer to Figure 2 The mobile device 20 can also be a wearable device for the ear. The mobile device 20 may include an ear strap 21 or other fixing parts that are attached to the user's body, and the user can hang the ear strap 21 on their ear to wear the mobile device 20. When the user is wearing the mobile device 20, the main body of the mobile device 20 can be inserted into the user's external auditory canal.

[0028] The sensor device can be mounted on the body of the mobile device 20 or on the ear strap 21. For example, the sensor device can be placed on the ear strap 21, which is in contact with the user's skin, to output light to the user's body and detect 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 can use the biometric information to provide various applications.

[0029] Figure 3 This is a schematic diagram of a sensor device according to an example embodiment.

[0030] refer to Figure 3 The sensor device 30 according to the example embodiment can operate in close proximity to a user's body 40 and may include a light-emitting unit 31 and a sensor array 32. The sensor array 32 may include a plurality of sensing elements 33. For example, each of the plurality of sensing elements may include a photodiode. For example, the sensor device 30 may be a multi-channel optical sensor including a plurality of photodiodes, and may be a photoplethysmography (PPG) sensor or a spectrometer.

[0031] refer to Figure 3 The light-emitting unit 31 can emit light toward the user's body 40. The light-emitting unit 31 may include at least one light source. According to an example embodiment, the light source may emit light of a specific wavelength. For example, the wavelength of the light emitted by the light source may vary depending on the biometric information to be determined using the sensor device 30.

[0032] For example, when the intention is to determine heart rate from the user's body 40, a light source emitting green light may be included in the light-emitting unit 31. In another example, when the intention is to determine blood oxygen saturation from the user's body 40, a light source emitting red and infrared light may be included in the light-emitting unit 31. Multiple light sources emitting different wavelengths of light may constitute the light-emitting unit 31. The light-emitting unit 31 may operate at least one of the multiple light sources based on the biometric information to be determined and may obtain signals from the sensor array 32.

[0033] In an example embodiment, the sensor array 32 may include a plurality of sensing elements 33 arranged in a matrix. However, the arrangement of the sensing elements 33 may vary depending on the example embodiment. Each sensing element 33 may include a photodiode that generates an electrical signal in response to light. A signal processing module included in the sensor device 30 may process the electrical signal to generate a digital signal. A processor of a mobile device equipped with the sensor device 30 may use the digital signal to determine biometric information.

[0034] Figure 4 This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0035] refer to Figure 4 The sensor array 50 of the sensor device according to the example embodiment 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.

[0036] Light emitted by the light-emitting unit and reflected from the user's body (e.g., blood vessels 41 in the user's body) (see Figure 3 It can appear in all bands, such as Figure 4 The first figure 60 is shown. However, as mentioned above, depending on the type of biometric information to be determined using the sensor device, light of a specific wavelength band can be selectively used. For this purpose, the sensor array 50 may include a filter layer 51. As shown in the second figure 70, the filter layer 51 allows light of a specific wavelength band to selectively pass through the layer and can emit that light to the photodiode layer 52. Therefore, including according to Figure 4 The sensor device of the sensor array 50 shown in the example embodiment can operate as a multi-wavelength PPG sensor.

[0037] Therefore, the sensitivity of the sensor device can be improved. A portion of the light source emitting light in all wavelength bands can constitute the light-emitting unit, and light of the desired wavelength band can be selectively incident on the photodiode through the filter layer 51, thereby realizing a sensor device that can determine various types of biometric information using a single light source. For this purpose, at least some of the multiple color filters can allow portions of light in different wavelength bands to pass through.

[0038] For example, among multiple color filters, the first color filter 51A may allow only green wavelength light to pass through. The first color filter 51A may have a structure in which an infrared cutoff color filter and a green color filter (allowing only green wavelength light to pass through) are stacked. Therefore, in the portion of light emitted from the light source of the light-emitting unit and reflected from the blood vessels, only green wavelength light can be incident on the first photodiode 52A below the first color filter 51A. The processor of a mobile device equipped with sensor devices can use the current signal output from the first photodiode 52A to determine the user's heart rate and pulse rate.

[0039] In a plurality of color filters, the second color filter 51B allows only red-band light to pass through, and the third color filter 51C allows only infrared-band light to pass through. Therefore, in the portion of light emitted from the light source of the light-emitting unit and reflected from the blood vessels, red-band light can be incident on the second photodiode 52B below the second color filter 51B, and infrared-band light can be incident on the third photodiode 52C below the third color filter 51C. The processor of a mobile device equipped with sensor devices can use the current signals output from the second photodiode 52B and the third photodiode 52C to determine the user's blood oxygen saturation.

[0040] To enable a single sensor device to determine various types of biometric information, the sensor array 50 may include a filter layer 51 and a photodiode layer 52, as shown in the reference. Figure 4 The photodiodes included in the photodiode layer 52 can be connected via multiple channels to a signal processing module for processing current signals, enabling the processing of current signals output from the sensor array 50 according to the example embodiment to determine desired biometric information. The signal processing module can be configured to independently process current signals received through multiple channels to generate digital signals. However, in this case, the area occupied by the signal processing module and its power consumption may increase.

[0041] In an example embodiment, the sensor device may use a signal processing module to process the current signal generated by the sensor array 50. The sensor device according to the example embodiment may include an encoder connected between the input of the signal processing module and the sensor array 50, and a decoder connected to the output of the signal processing module. The encoder may encode the current signal received through multiple channels to generate an analog signal, and may sequentially input the analog signal to the signal processing module. While the signal processing module sequentially processes the analog signal to output a digital signal, the decoder may use the digital signal to generate a data signal corresponding to the multiple channels. Therefore, a single signal processing module can be used to process the current signal received through multiple channels, and the area and power consumption of the sensor device can be reduced. Furthermore, the impact of noise generated during the process of the signal processing module converting the current signal into a data signal can be reduced. This aspect and other aspects of the example embodiment are described in further detail below.

[0042] Figure 5 This is a schematic diagram of a sensor device according to an example embodiment.

[0043] refer to Figure 5 According to an example embodiment, the sensor device 100 may include a substrate 101, a light source 110 mounted on a first surface of the substrate 101, a plurality of photodiodes 120 mounted together with the light source 110 on the first surface, a signal processing device 130, etc. According to an example embodiment, the signal processing device 130 may be mounted on a second surface of the substrate 101 opposite to the first surface. The substrate 101 may include a connector 140. The processor of the mobile device (in which the sensor device 100 is mounted) and the sensor device 100 may be electrically connected to each other via the connector 140.

[0044] refer to Figure 5The photodiodes 120 can be arranged to be distributed around the light source 110. However, this is only an example embodiment, and the number and position of the photodiodes 120 can vary. As mentioned above, color filters that allow light of a specific wavelength to selectively pass through can be further arranged above the photodiodes 120.

[0045] refer to Figure 5 The sensor device 100 may include four photodiodes 120, and the signal processing device 130 may receive current signals from the photodiodes 120 through four channels.

[0046] According to this example embodiment, the signal processing device 130 may include an encoder that receives current signals through four channels, a signal processing module that processes the analog signals output by the encoder to output digital signals, and a decoder that uses the digital signals output by the signal processing module to recover data signals corresponding to the four channels.

[0047] Figure 6 This is a schematic block diagram of a mobile device according to an example embodiment.

[0048] refer to Figure 6 The mobile device 200 according to the example embodiment may include a sensor device 210 and a processor 220. The processor 220 may be a semiconductor device that controls all operations of the mobile device 200 and may use digital signals output by the sensor device 210 to determine information related to the object OBJ. For example, when the object OBJ is a human body, the processor may determine information such as heart rate, blood oxygen saturation, blood pressure, etc., and may execute various applications based on this information.

[0049] The sensor device 210 may include a light source 211, a light source driver 212, a sensor array 213, a signal processing device 214, etc.

[0050] The light source 211 can emit light toward the object OBJ in response to a light control signal output from the light source driver 212. For example, the light control signal output from the light source driver 212 to the light source 211 can be a pulse width modulation (PWM) signal. Therefore, when the sensor device 210 is operational, the light source 211 can be repeatedly switched on and off.

[0051] Sensor array 213 may include a plurality of photodiodes PD. According to an example embodiment, sensor array 213 may also include a color filter that allows light of a predetermined wavelength to be selectively incident on the photodiodes PD. The photodiodes PD may generate a current signal in response to light emitted by light source 211 and reflected from object OBJ. According to an example embodiment, light source 211 may be omitted. In this case, the photodiodes PD may generate a current signal in response to light incident from object OBJ, etc.

[0052] Signal processing device 214 can convert current signals into digital signals and output the digital signals to processor 220. Since light source 211 can be repeatedly switched on and off at a predetermined frequency when sensor device 210 is operational, signal processing device 214 can be synchronized with light source driver 212 to obtain current signals from photodiodes PD during the time light source 211 is on. Signal processing device 214 may include: an encoder that receives current signals from photodiodes PD of sensor array 213 through various channels; a signal processing module that processes the analog signals output by the encoder to output digital signals; and a decoder that uses the digital signals output by the signal processing module to recover data signals corresponding to each channel, etc.

[0053] Figure 7 This is a schematic block diagram of a sensor device according to an example embodiment.

[0054] refer to Figure 7 The sensor device 300 according to the example embodiment may include a plurality of photodiodes PD1 to PD4, a signal processing module 310, an encoder 320, a decoder 330, etc.

[0055] Photodiodes PD1 to PD4 can generate current signals I1 to I4 in response to external incident light. For example, photodiodes PD1 to PD4 can have incident light emitted from an additional light source to generate current signals I1 to I4 in response to light reflected from an object, and the object can be part of a user's body. Current signals I1 to I4 can be input to encoder 320 through multiple analog channels ACH1 to ACH4.

[0056] Encoder 320 can be connected to photodiodes PD1 to PD4 via analog channels ACH1 to ACH4, and can be connected to the input terminal of signal processing module 310 via a single input channel ICH. Encoder 320 can encode current signals I1 to I4 to generate analog signals, and can sequentially input analog signals to signal processing module 310 via input channel ICH. Therefore, signal processing module 310 can sequentially receive analog signals via input channel ICH. Each analog signal encoded by encoder 320 can be a signal including current signals I1 to I4, and can be a signal obtained by encoding current signals I1 to I4 based on a predetermined orthogonal code.

[0057] Signal processing module 310 can process sequentially input analog signals to generate digital signals. For example, encoder 320 can use four current signals I1 to I4 to generate four analog signals, and signal processing module 310 can convert the four analog signals into the digital domain to output four digital signals. Signal processing module 310 can sequentially output the four digital signals to decoder 330 through a single output channel OCH connected to the output terminal.

[0058] Decoder 330 can generate data signals DATA1 to DATA4 using digital signals. Data signals DATA1 to DATA4 can be output separately through multiple digital channels DCH1 to DCH4. Each data signal DATA1 to DATA4 can be obtained by converting each current signal I1 to I4 into the digital domain. For example, the first data signal DATA1 can be obtained by converting the first current signal I1 into the digital domain, and the second data signal DATA2 can be obtained by converting the second current signal I2 into the digital domain.

[0059] Decoder 330 can generate data signals DATA1 to DATA4 based on the orthogonal codes used when encoder 320 encodes current signals I1 to I4 to generate analog signals. For example, decoder 330 can recover data signals DATA1 to DATA4 from digital signals using the inverse matrix of the orthogonal matrix corresponding to the orthogonal codes.

[0060] The signal processing module 310 may be an analog front-end (AFE) module. The signal processing module 310 may include a current-to-voltage converter that converts the analog signals generated from current signals I1 to I4 into voltage, an amplifier that amplifies the analog signals, an analog-to-digital converter (ADC), etc. The following will refer to... Figure 8 The signal processing module 310 is described in more detail.

[0061] Figure 8 This is a schematic diagram of a signal processing module included in a sensor device according to an example embodiment.

[0062] refer to Figure 8 The signal processing module 310 according to the example embodiment may include a current-to-voltage converter 311, an amplifier 312, an analog-to-digital converter 313, etc. The current-to-voltage converter 311 may be a circuit that converts analog signals received sequentially through the input channel ICH into voltages, and may include, for example, an operational amplifier, a feedback resistor, etc. The voltage signal output by the current-to-voltage converter 311 may be sent to the amplifier 312, and the amplifier 312 may include a programmable gain amplifier.

[0063] The analog-to-digital converter 313 can convert the voltage signal output by the amplifier 312 into a digital domain to generate a digital signal, and can output the digital signal through the output channel OCH. In the operation of the signal processing module 310, analog signals can be sequentially input by encoders connected to the input terminals of the signal processing module 310, and the analog-to-digital converter 313 can sequentially output digital signals corresponding to the analog signals.

[0064] Figure 9 This is a schematic diagram of a sensor device according to an example embodiment.

[0065] refer to Figure 9 According to an example embodiment, the sensor device 400 may include a signal processing module 410, an encoder 420, a decoder 430, etc. The encoder 420 may be connected to multiple photodiodes PD1 to PD4 and may encode current signals I1 to I4 to generate an analog signal AIN. The analog signal AIN may be sequentially input to the signal processing module 410.

[0066] The signal processing module 410 can perform digital conversion on the analog signal AIN to generate a digital signal DOUT. The digital signal DOUT can be input to the decoder 430, and the decoder 430 can use the digital signal DOUT to generate data signals DATA1 to DATA4. For example, data signals DATA1 to DATA4 can correspond to current signals I1 to I4 generated by photodiodes PD1 to PD4, respectively.

[0067] exist Figure 9 In the illustrated example embodiment, encoder 420 may include multiple multipliers 421 to 424 and adder 425. Multipliers 421 to 424 may receive encoding coefficients ENC1 to ENC4 respectively and output signals obtained by multiplying current signals I1 to I4 by encoding coefficients ENC1 to ENC4. Encoding coefficients ENC1 to ENC4 may not be zero. Adder 425 may add the multiplied signals (i.e., the signals generated by multiplying encoding coefficients ENC1 to ENC4 by current signals I1 to I4) to generate an analog signal AIN.

[0068] The encoding coefficients ENC1 to ENC4 can be determined by the orthogonal code used by encoder 420 to encode current signals I1 to I4 to generate analog signal AIN. For example, the values ​​of encoding coefficients ENC1 to ENC4 can be changed when multiple photodiodes PD1 to PD4 output current signals I1 to I4. When the number of photodiodes PD1 to PD4 is 4, encoder 420 can divide the output time of current signals I1 to I4 into four unit times (each unit time can have a duration corresponding to the time it takes for the signal processing module to convert each analog signal to the digital domain), and at least one of the encoding coefficients ENC1 to ENC4 can be set to a different value within each unit time (see below). Figure 10 Describes the coding coefficients ENC1 to ENC4 and the operation of the encoder 420 that depends on them.

[0069] Still referencing Figure 9 The decoder 430 may include multiple multipliers 431 to 434 and multiple accumulators 435 to 438. For example, one of the multipliers 431 to 434 and one of the accumulators 435 to 438 may be assigned to each digital channel of the output data signals DATA1 to DATA4.

[0070] Multipliers 431 to 434 can receive decoding coefficients DEC1 to DEC4 respectively, and can multiply each sequentially output digital signal DOUT by decoding coefficients DEC1 to DEC4. Accumulators 435 to 438 can sequentially accumulate and sum the digital signals DOUT obtained by multiplying by decoding coefficients DEC1 to DEC4 to generate data signals DATA1 to DATA4.

[0071] The decoding coefficients DEC1 to DEC4 can be determined by the inverse matrix of the orthogonal code used by encoder 420. In an example embodiment, the absolute value of each of the decoding coefficients DEC1 to DEC4 may be less than the absolute value of each of the encoding coefficients ENC1 to ENC4.

[0072] The following will refer to Figure 10 , 11A Section 11B describes a sample operation of sensor device 400 in detail.

[0073] Figure 10 This is a timing diagram illustrating the operation of a sensor device according to an example embodiment, and Figure 11A and 11B This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0074] refer to Figure 10Photodiodes PD1 to PD4 can output current signals I1 to I4 during the light emission time TON (during which the light source is turned on by the light control signal). Sensor device 400 can divide the light emission time TON into multiple unit times T1 to T4, and encoder 420 can adjust the encoding coefficients ENC1 to ENC4 in each unit time T1 to T4 to generate an analog signal AIN.

[0075] For example, during the first unit time T1, the coding coefficients ENC1 to ENC4 can be determined as [+1, -1, -1, -1]. Therefore, during the first unit time T1, the first analog signal AIN1 input to the signal processing module 410 can be determined as [I1-I2-I3-I4]. During the next second unit time T2, the coding coefficients ENC1 to ENC4 can be determined as [-1, +1, -1, -1], so the signal processing module 410 can receive the second analog signal AIN2 defined as [-I1+I2-I3-I4]. Similarly, during the third unit time T3, the third analog signal AIN3 input to the signal processing module 410 can be represented by [-I1-I2+I3-I4], and the fourth analog signal AIN4 input to the signal processing module 410 can be represented by [-I1-I2-I3+I4].

[0076] The signal processing module 410 can sequentially convert the first to fourth analog signals AIN1 to AIN4 into the digital domain to output the first to fourth digital signals DOUT1 to DOUT4. For example... Figure 10 As shown, the output timing of the first to fourth digital signals DOUT1 to DOUT4 can be determined by the time required for the signal processing module 410 to convert each of the first to fourth analog signals AIN1 to AIN4 into the digital domain. The delay time (i.e., 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 vary depending on the configuration of the signal processing module 410.

[0077] The encoding code used by encoder 420 to encode current signals I1 to I4 to generate analog signal AIN can be a code generated based on orthogonal codes, and can be represented by an orthogonal matrix (e.g., an N×N matrix, where N is the number of photodiodes (where N is a positive integer of 2 or greater)). As an example, in reference... Figure 10 In the described example embodiment, the encoded code can be represented by Equation 1 below. The rows of the encoded code can correspond to unit times T1 to T4 respectively, and the columns can correspond to encoding coefficients ENC1 to ENC4 respectively. As shown in Equation 1, the encoding coefficients ENC1 to ENC4 may not be zero.

[0078] Equation 1

[0079]

[0080] Furthermore, the decoding coefficients DEC1 to DEC4 used by decoder 430 to recover data signals DATA1 to DATA4 from digital signal DOUT can be determined by the decoding code represented by the inverse of an orthogonal matrix. As an example, the decoding code corresponding to the encoding code represented in Equation 1 can be represented by Equation 2 below. In the decoding code, columns can correspond to decoding coefficients DEC1 to DEC4 respectively. As shown in Equations 1 and 2, the absolute value of each decoding coefficient DEC1 to DEC4 can be less than the absolute value of each encoding coefficient ENC1 to ENC4.

[0081] Equation 2

[0082]

[0083] The following will refer to Figure 11A and 11B The operation of encoder 420 and decoder 430 is described in more detail.

[0084] Figure 11A This is a diagram used to describe the operation of encoder 420.

[0085] refer to Figure 11A The current signals I1 to I4 generated by photodiodes PD1 to PD4 can be represented by a matrix, and as a result of the operation on the encoded code of the current signals I1 to I4, the first to fourth analog signals AIN1 to AIN4 can be generated.

[0086] For example, the first to fourth analog signals AIN1 to AIN4 can be sequentially input to the signal processing module 410, and the signal processing module 410 can digitally convert each of the first to fourth analog signals AIN1 to AIN4 to sequentially output the first to fourth digital signals DOUT1 to DOUT4. Accordingly, noise can be generated during the digital conversion operation of the signal processing module 410 on the first to fourth analog signals AIN1. Therefore, each of the first to fourth digital signals DOUT1 to DOUT4 may include a predetermined noise component V. N (exist Figure 11A In the diagram, the first to fourth digital signals DOUT1 to DOUT4 are shown as including noise components V of the same magnitude. N However, at least some of the signals DOUT1 to DOUT4 may include noise components V of different magnitudes. N ).

[0087] Figure 11B This is a diagram used to describe the operation of decoder 430.

[0088] refer to Figure 11B The operation of decoder 430 can be represented by decoding code. When signal processing module 410 outputs the first digital signal DOUT1, the decoding coefficients DEC1 to DEC4 can be defined as [+1 / 4, -1 / 4, -1 / 4, -1 / 4, -1 / 4]. Therefore, +1 / 4*DOUT1 can be input to the first accumulator 435, and -1 / 4*DOUT1 can be input to each of the second to fourth accumulators 436 to 438. Next, when signal processing module 410 outputs the second digital signal DOUT2, the decoding coefficients DEC1 to DEC4 can be determined as [-1 / 4, +1 / 4, -1 / 4, -1 / 4, -1 / 4], so +1 / 4*DOUT2 can be input to the second accumulator 436, and -1 / 4*DOUT2 can be input to each of the first, third, and fourth accumulators 435, 437, and 438. When signal processing module 410 outputs the third digital signal DOUT3, the decoding coefficients DEC1 to DEC4 can be determined as [-1 / 4, -1 / 4, +1 / 4, -1 / 4]. Therefore, +1 / 4 * DOUT3 can be input to the third accumulator 437, and -1 / 4 * DOUT3 can be input to each of the first, second, and fourth accumulators 435, 436, and 438. Finally, when signal processing module 410 outputs the fourth digital signal DOUT4, the decoding coefficients DEC1 to DEC4 can be determined as [-1 / 4, -1 / 4, -1 / 4, +1 / 4]. Therefore, +1 / 4 * DOUT4 can be input to the fourth accumulator 438, and -1 / 4 * DOUT4 can be input to each of the first to third accumulators 435 to 437.

[0089] As described above, after the signal processing module 410 outputs to the fourth digital signal DOUT4, the signal accumulated and summed in each accumulator 435 to 438 can be represented by the following equation 3.

[0090] Equation 3

[0091] 1st Accumulator=1 / 4*(DOUT1-DOUT2-DOUT3-DOUT4)

[0092] 2nd Accumulator=1 / 4*(-DOUT1+DOUT2-DOUT3-DOUT4)

[0093] 3rd Accumulator=1 / 4*(-DOUT1-DOUT2+DOUT3-DOUT4)

[0094] 4th Accumulator=1 / 4*(-DOUT1-DOUT2-DOUT3+DOUT4)

[0095] The digital signals DOUT1 to DOUT4 output from the signal processing module 410 may include a noise component V. N And you can refer to the above. Figure 11A The definition is as described above. (Referencing...) Figure 11A When the described digital signals DOUT1 to DOUT4 are applied to Equation 3, the data signals DATA1 to DATA4 output from accumulators 435 to 438 can be as follows: Figure 11B As defined. In other words, each of the data signals DATA1 to DATA4 may include data obtained by converting each of the current signals I1 to I4 into the digital domain, as well as a noise component of 0.5V reduced by averaging through the operation of decoder 430. N .

[0096] In the example embodiment, encoder 420 and decoder 430 can be connected to the input and output terminals of signal processing module 410, respectively, and encoder 420 can input current signals I1 to I4 received through multiple analog channels to signal processing module 410. Signal processing module 410 can convert analog signal AIN into digital signal DOUT, and then sequentially output digital signal DOUT to decoder 430. In this case, a predetermined noise component V can be reflected in each digital signal DOUT. N When the decoder 430 uses the digital signal DOUT to recover the data signals DATA1 to DATA4 corresponding to the current signals I1 to I4, the noise component V N It can be cancelled and / or reduced. Therefore, the sensor device 400 can be implemented with improved signal-to-noise ratio (SNR) characteristics.

[0097] The configuration of the encoding and decoding codes used for the operation of encoder 420 and decoder 430 is not limited to the reference. Figure 10 , 11A The configuration is the same as described in 11B. The encoding coefficients ENC1 to ENC4 and the decoding coefficients DEC1 to DEC4, which define the encoding code and decoding code respectively, can be freely chosen while satisfying the characteristics of orthogonal codes. The size of the matrix representing the encoding code and decoding code can be determined based on the number of sensing elements (e.g., the number of photodiodes PD connected to the signal processing module 410).

[0098] Figure 12A and 12B This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0099] refer to Figure 12A and 12B The sensor device may include eight sensing components. Therefore, as... Figure 12A As shown, the encoded code can be represented by an 8×8 matrix. In Figure 12A In the illustrated embodiment, all diagonal components of the encoded code can be +1, and all other components can be -1. However, this is only an example embodiment, and the components of the encoded code can vary while satisfying the properties of orthogonal codes.

[0100] The sensor device can divide the emission time of the light source during its period into eight unit times T1 to T8. At least some of the coding coefficients ENC1 to ENC8 can have different values ​​in each of the unit times T1 to T8, and the signal processing module can sequentially receive eight analog signals AIN1 to AIN8 generated by the encoder during the transmission time.

[0101] Figure 12B This is a diagram used to describe the operation of the decoder.

[0102] refer to Figure 12B The decoding code can be the inverse matrix of the encoding code and can be represented by an 8×8 matrix. The digital signals DOUT1 to DOUT8, obtained by digitally converting analog signals AIN1 to AIN8 by the signal processing module, can be recovered into data signals DATA1 to DATA8 through the decoding code. As an example, each of the data signals DATA1 to DATA8 may include data obtained by converting each of the current signals I1 to I8 into the digital domain, and data averaged by the decoder with a reduced noise component of 0.75V. N .

[0103] Therefore, the noise characteristics of the sensor device can be improved compared to not using an encoder and decoder. Furthermore, a single signal processing module can process current signals output from multiple sensing elements, thereby increasing the integration of the sensor device and reducing power consumption.

[0104] Figure 13 This is a diagram illustrating the operation of a sensor device according to an example embodiment.

[0105] refer to Figure 13As the number of photodiodes included in a sensor device increases, the signal-to-noise ratio (SNR) of the sensor device may increase. For example, compared to the SNR (90 dB) when the signal processing module uses a current signal generated by a single photodiode to generate a data signal, the SNR (96 dB) when using a current signal generated by four photodiodes can be improved by approximately 6 dB. Furthermore, when using a current signal generated by eight photodiodes to generate a data signal, the SNR (99 dB) can be improved by approximately 9 dB compared to a single photodiode (90 dB). Therefore, the SNR and sensor device performance can be improved by increasing the number of emitting photodiodes and generating current signals in response to light reflected from sources such as the user's body.

[0106] However, as the number of photodiodes increases, the number of channels connecting the signal processing module and the photodiodes may also increase, potentially increasing the power consumption and circuit area occupied by the signal processing module. In an example embodiment, this problem can be addressed by connecting the encoder and decoder to the input and output terminals of the signal processing module, respectively. The current signals generated by the photodiodes, after being encoded into analog signals by the encoder, can then be sequentially input to the signal processing module, which can sequentially output digital signals. The decoder can then use the sequentially output digital signals to recover the data signal. Therefore, only one signal processing module can process the current signals from photodiodes connected to multiple channels, thereby reducing the power consumption and circuit area of ​​the sensor device and lowering its manufacturing cost.

[0107] In another example embodiment, the sensor device may include two or more signal processing modules. For example, when N photodiodes are connected through N channels, the N photodiodes can be divided in half, and then N / 2 photodiodes can be allocated and connected to each of the two signal processing modules. In this case, the number of photodiodes connected to each signal processing module and the number of current signals that each signal processing module needs to process can be reduced accordingly to improve the operating speed of the sensor device.

[0108] Figure 14 This is a schematic diagram of a sensor device according to an example embodiment.

[0109] exist Figure 14 In the example embodiment shown, the sensor device 500 may include multiple photodiodes PD1 to PD4, a signal processing module 510, an encoder 520, a decoder 530, etc. As described above, the number of photodiodes PD1 to PD4 can vary.

[0110] The encoder 520 may include multiple pairs of switches SW1 and SW2, for example, a positive switch and a negative switch, respectively. Each of the photodiodes PD1 to PD4 may be connected to one of the switch pairs SW1 and SW2.

[0111] The activation (e.g., on / off) of switches SW1 and SW2 can be determined by coding coefficients ENC1 to ENC4.

[0112] For example, switches SW1 and SW2 cannot be turned on simultaneously. For example, when the first switch SW1 is turned on, the second switch SW2 can be turned off. At the same time, when the second switch SW2 is turned on, the first switch SW1 can be turned off.

[0113] refer to Figure 14 The signal processing module 510 can receive analog signals in a differential signal manner through the positive input terminal 511 and the 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.

[0114] The operation of encoder 520 can be similar to that of reference. Figure 10 and 11A The operation described above. For example, a first switch SW1 connected to a first photodiode PD1 can be turned on by a first encoding coefficient ENC1 for a first unit time, and a second switch SW2 connected to second to fourth photodiodes PD2 to PD4 can be turned on by encoding coefficients ENC2 to ENC4 for second to fourth photodiodes. Therefore, the analog signal AIN input to the signal processing module 510 for the first unit time can be defined as [I1-I2-I3-I4]. Similarly, for the second unit time, a second switch SW2 connected to a second photodiode PD2 can be turned on, and a first switch SW1 connected to the first, third, and fourth photodiodes PD1, PD3, and PD4 can be turned on. Therefore, the encoder 520 can be referenced... Figure 10 and 11A The decoder 530 can also operate in a similar manner as described in the reference. Figure 11B The described operation.

[0115] Figures 15 to 17 This is a diagram showing a comparative example of sensor devices.

[0116] refer to Figure 15 In the sensor device 600 according to the 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 of the signal processing module 610 via multiple switches SW1 to SW4.

[0117] Figure 16 This is a timing diagram used to describe the operation of sensor device 600.

[0118] refer to Figure 16 The first to fourth switches SW1 to SW4 can be turned on sequentially at the first to fourth timings T1 to T4, respectively. Therefore, the first to fourth current signals I1 to I4 can be sequentially input into 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.

[0119] The operation of sensor device 600 can be represented as follows: Figure 17 The matrix shown.

[0120] refer to Figure 17 During the first to fourth timing periods T1 to T4, the operation of the first to fourth switches SW1 to SW4 can be represented by a matrix, where all diagonal components are 1 and other components are 0. During the first timing period T1, only the first switch SW1 can be turned on to input the first current signal I1 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 can be performed in each of the second to fourth timing periods T2 to T4.

[0121] Therefore, the noise component V generated during the operation of the signal processing module 610 N This can be reflected as is in the first to fourth digital signals DOUT1 to DOUT4. In the comparative example (different from the example embodiment above, where the encoder and decoder are not connected to the input and output of the signal processing module 610), the noise component V generated during the operation of the signal processing module 610 is not expected. N This will be averaged to reduce the size. Reference is made to an example embodiment including four photodiodes PD1 to PD4, as shown relative to the comparative example. Figure 11A and 11B Noise component V N The signal-to-noise ratio (SNR) can be reduced by half compared to the comparison example by the decoder. Therefore, according to the example embodiment, a sensor device with improved signal-to-noise ratio (SNR) and improved noise characteristics can be realized.

[0122] Figure 18 This is a schematic block diagram of a mobile device according to an example embodiment.

[0123] refer to Figure 18The mobile device 1000 may include a camera 1100, a display 1200, an audio processing unit 1300, a modem 1400, DRAM 1500a and 1500b, flash memory devices 1600a and 1600b, input / output (I / O) devices 1700a and 1700b, a sensor device 1800, and an application processor (hereinafter referred to as "AP") 1900.

[0124] The mobile device 1000 can be implemented as, for example, a laptop computer, a portable terminal, a smartphone, a tablet PC, a wearable device, a healthcare device, or an Internet of Things (IoT) device. Furthermore, the mobile device 1000 can be implemented as a server or a PC.

[0125] Various components included in the mobile device 1000 can operate synchronously with a predetermined clock. For example, the display 1200 can display images according to a predetermined scan rate, and the DRAMs 1500a and 1500b and flash memory devices 1600a and 1600b can store and retrieve data at a predetermined speed, or operate according to a predetermined clock to exchange data with other external devices. I / O devices 1700a and 1700b and the application processor 1900 can also operate according to a predetermined clock.

[0126] Camera 1100 can capture still images or videos under user control. Mobile device 1000 can use the still images / videos captured by camera 1100 to obtain specific information, or can convert and store the still images / videos as other types of data such as text. Camera 1100 may include multiple cameras with different fields of view, stop values, etc. Camera 1100 may also include a camera that generates a depth image using depth information of the object and / or background, and a camera that images the object to generate an actual image.

[0127] Display 1200 can provide touchscreen functionality for use as an input device for mobile device 1000. Furthermore, display 1200 can be integrated with a fingerprint sensor or similar device to provide security features for mobile device 1000. Audio processing unit 1300 can process audio data stored in flash memory devices 1600a and 1600b, or audio data included in content received from external devices via modem 1400 or I / O devices 1700a and 1700b.

[0128] The modem 1400 can modulate and transmit modulated signals to send and receive wired / wireless data, and can demodulate externally received signals to recover the original signals. I / O devices 1700a and 1700b can provide digital inputs and outputs, and may include input devices such as ports for connecting to external recording media, touchscreens, or mechanical button keys, as well as output devices capable of outputting vibrations in a tactile manner.

[0129] Sensor device 1800 may include multiple sensors for collecting various types of external information. In an example embodiment, sensor device 1800 may include an illuminance sensor for detecting light intensity, a gyroscope sensor for detecting movement of mobile device 1000, a multi-channel optical sensor for obtaining biometric information from a user's body in contact with and / or near mobile device 1000, etc. For example, the multi-channel optical sensor may include a photoplethysmography (PPG) sensor and / or a spectrometer. The multi-channel optical sensor included in sensor device 1800 may include a light source, a sensor array, and a signal processing module for processing signals generated by the sensor array. As an example, references above may be made to... Figures 3 to 14 The example embodiments described above implement multi-channel optical sensors.

[0130] The AP 1900 can use data signals output from a multi-channel optical sensor to measure biometric information about a user's body, such as pulse rate, heart rate, blood oxygen saturation, and blood pressure, and can execute applications based on this biometric information.

[0131] AP 1900 can control all operations of mobile device 1000. For example, AP 1900 can control display 1200 to display portions of content stored in flash memory devices 1600a and 1600b on the screen. Additionally, when receiving user input via I / O devices 1700a and 1700b, AP 1900 can perform control operations corresponding to the user input.

[0132] In an example embodiment, AP 1900 may include accelerator block 1920. According to another example embodiment, a separate accelerator chip, separate from AP 1900, may be provided, and DRAM 1500b may be additionally connected to accelerator block 1920 or the accelerator chip. Accelerator block 1920 may be a function block dedicated to performing specific functions of AP 1900, and may include a graphics processing unit (GPU) serving as a function block dedicated to processing graphics data, a neural processing unit (NPU) serving as a function block dedicated to performing AI computations and interference, a data processing unit (DPU) serving as a function block dedicated to transmitting data, etc.

[0133] As described above, in the example embodiment, the current signals output by multiple photodiodes can be encoded and then input to a single signal processing module. The signal output by the signal processing module can be decoded to generate a data signal corresponding to the current signal. Therefore, noise reflected in the data signal during the conversion of the current signal to the data signal can be reduced, thereby improving noise characteristics such as the signal-to-noise ratio (SNR).

[0134] As described above, the example embodiments can provide sensor devices and mobile devices, including sensor devices and mobile devices with improved noise characteristics. The example embodiments can encode current signals generated by multiple photodiodes, process the current signals by a single signal processing module, and decode the output of the signal processing module into a data signal corresponding to the current signals.

[0135] This document discloses exemplary embodiments, and although specific terminology is used, it is used and interpreted in a general and descriptive sense only and not for limitation. In some instances, as will be apparent to those skilled in the art upon filing this application, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless expressly indicated otherwise. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. A sensor device, comprising: A sensor array, comprising multiple photodiodes, is configured to generate a current signal in response to light; The encoder is configured to encode the current signal based on a predetermined orthogonal code to generate a plurality of analog signals, and to sequentially output the plurality of analog signals; A signal processing module is configured to process the analog signal received from the encoder to generate a digital signal; as well as The decoder is configured to decode the digital signal received from the signal processing module based on the inverse matrix of the orthogonal code to generate a plurality of data signals corresponding to the current signal.

2. The sensor device as described in claim 1, wherein, The data signal includes biometric information to generate at least one of heart rate, blood oxygen saturation, and blood pressure.

3. The sensor device as described in claim 1, wherein, The sensor array is configured to generate the current signal in response to light reflected from blood vessels in the human body.

4. The sensor device as described in claim 1, wherein, The number of the plurality of photodiodes is N, where N is a positive integer of 2 or greater, and the orthogonal code is defined as an N×N matrix.

5. The sensor device as described in claim 1, wherein, The encoder includes a multiplier connected between the plurality of photodiodes and the input of the signal processing module, and is configured to multiply each of the analog signals by a predetermined coefficient.

6. The sensor device as claimed in claim 1, wherein: The signal processing module includes a positive input terminal and a negative input terminal, and 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.

7. The sensor device as claimed in claim 6, wherein, When the positive switch connected to one of the plurality of photodiodes is turned on, the negative switches connected to the other photodiodes are turned off.

8. The sensor device as claimed in claim 7, wherein, When the plurality of photodiodes output the analog signal, the plurality of positive switches are sequentially turned on.

9. The sensor device of claim 1, further comprising a light-emitting unit configured to emit light, wherein: The light-emitting unit is switched on for a period of time including multiple unit times, and The encoder multiplies at least some current signals by different coefficients in each of the plurality of time units, and sums the corresponding multiplication results to sequentially generate the analog signal.

10. The sensor device as claimed in claim 9, wherein, Each of the plurality of time units has a duration corresponding to the time it takes for the signal processing module to convert each analog signal into the digital domain.

11. A sensor device, comprising: Multiple photodiodes are configured to generate current signals in response to light; An encoder, connected to the plurality of photodiodes via multiple analog channels, includes multipliers and adders based on predetermined orthogonal code operations, and is configured to sequentially output a plurality of analog signals obtained by encoding the current signal to a single input channel; The signal processing module includes an input terminal connected to the input channel and is configured to sequentially output a plurality of digital signals corresponding to the analog signal to an output terminal; A decoder, connected to the output, is configured to output multiple data signals obtained by decoding the digital signal according to the inverse matrix of the orthogonal matrix corresponding to the orthogonal code to multiple digital channels; as well as The processor is configured to use the data signal to generate information corresponding to the current signal.

12. The sensor device of claim 11, wherein, The encoder multiplies the current signal by coding coefficients determined from the orthogonal code and sums the corresponding multiplication results to generate the analog signal.

13. The sensor device as claimed in claim 12, wherein, None of the coding coefficients are zero.

14. The sensor device as claimed in claim 13, wherein, In the coding coefficients used for each current signal, one of the coding coefficients is 1, and the others are -1.

15. The sensor device as claimed in claim 12, wherein, The decoder multiplies the digital signal by decoding coefficients determined from the orthogonal code and sums the corresponding multiplication results to generate the data signal.

16. The sensor device as claimed in claim 15, wherein, The absolute value of each of the decoding coefficients is less than the absolute value of each of the encoding coefficients.

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

19. A mobile device, comprising: substrate; Multiple photodiodes are mounted on the substrate and configured to generate current signals in response to light incident from an object; A signal processing device, mounted on the substrate, is configured to convert the current signal into multiple data signals; as well as The processor is configured to use the data signal to obtain biometric information. The signal processing device is configured to sequentially convert multiple analog signals into multiple digital signals, and to generate the data signal by decoding the multiple digital signals using an inverse matrix based on a predetermined orthogonal code. The multiple analog signals are generated by encoding the current signals received through multiple input channels based on the predetermined orthogonal code.

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