Detection device

Abstract

To increase a frame rate and efficiently acquire a blood oxygen saturation, in a detection device.SOLUTION: The detection device comprises: a first photosensor for detecting light; a second photosensor provided adjacent to the first photosensor to detect light; a first light source for emitting light of a predetermined wavelength; a second light source for emitting light of a wavelength different from that of the light emitted by the first light source; a control unit for causing the first light source and the second light source to emit light simultaneously; and a signal processing unit for performing processing of acquiring blood oxygen saturation on the basis of a detection value by the first photosensor and a detection value by the second photosensor. The first photosensor and the second photosensor detect light reflected inside a living body or passing through the living body.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a detection device.

Background Art

[0002] There is known a detection device that obtains the oxygen saturation in blood (hereinafter referred to as blood oxygen saturation SpO2) based on transcutaneous data obtained by irradiating light from the skin into the body and detecting light transmitted through or reflected by an artery. The blood oxygen saturation SpO2 is the ratio of the amount of oxygen actually bound to hemoglobin to the total amount of oxygen assuming that all of the hemoglobin in the blood is bound to oxygen. When obtaining the blood oxygen saturation SpO2, for example, the pulse wave obtained by infrared light and the pulse wave obtained by red light are used (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As described above, in order to obtain the blood oxygen saturation SpO2, it is necessary to obtain pulse waves by two different wavelengths of light. When obtaining pulse waves by two different wavelengths of light, for example, it is conceivable to obtain data at different timings in a time-division manner. That is, a time-division process of obtaining the data of the pulse wave by the first wavelength light and then obtaining the data of the pulse wave by the second wavelength light is conceivable. However, considering efficiently obtaining the blood oxygen saturation, there is a limit to the above time-division process.

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a detection device capable of efficiently obtaining the blood oxygen saturation.

Means for Solving the Problems

[0006] To solve the above-mentioned problems and achieve the objective, a detection device according to one aspect of the present disclosure includes: a first photosensor for detecting light; a second photosensor provided adjacent to the first photosensor for detecting light; a first light source that emits light of a predetermined wavelength; a second light source that emits light of a different wavelength than the light emitted by the first light source; a control unit that causes the first light source and the second light source to emit light simultaneously; and a signal processing unit that performs processing to acquire blood oxygen saturation based on the value detected by the first photosensor and the value detected by the second photosensor. The first light source, the first light sensor, the second light sensor, and the second light source are arranged in that order, and when the first light source is lit, the second light source is not lit; when the second light source is lit, the first light source is not lit; when the first light source is lit and the second light source is not lit, the first light sensor is used and the second light sensor is not used; when the second light source is lit and the first light source is not lit, the first light sensor is also used and the second light sensor is not used; and when both the first and second light sources are lit, both the first and second light sensors are used. The first and second light sensors detect light that is reflected inside or transmitted through a living organism. [Effects of the Invention]

[0007] According to this disclosure, increasing the frame rate allows for more efficient acquisition of blood oxygen saturation levels. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the main components of a detection device according to a comparative example. [Figure 2] Figure 2 shows an example of the operation of the detection device shown in Figure 1. [Figure 3] Figure 3 shows the main components of the detection device disclosed herein. [Figure 4] Figure 4 shows an example of the operation of the detection device shown in Figure 3. [Figure 5] Figure 5 shows the usage status of the optical sensor in the example operation shown in Figure 4. [Figure 6] Figure 6 shows an example of the operation of the detection device of the present disclosure. [Figure 7] Figure 7 shows the usage status of the optical sensor in the example operation shown in Figure 6. [Figure 8] Figure 8 shows an example of using 10 pixels in a detection device. [Figure 9]FIG. 9 is a diagram showing an example in the case of calculating SpO2 using four pixels. [Figure 10] FIG. 10 is a diagram showing an example of a combination table in the case of combining two pixels out of four pixels. [Figure 11] FIG. 11 is a flowchart showing a process of calculating blood oxygen saturation SpO2 using a plurality of pixels and calculating an average value thereof. [Figure 12] FIG. 12 is a diagram showing a modified example of the arrangement of an optical sensor and a light source. [Figure 13] FIG. 13 is a plan view showing a detection device according to an embodiment. [Figure 14] FIG. 14 is a block diagram showing a configuration example of a detection device according to an embodiment. [Figure 15] FIG. 15 is a circuit diagram showing a detection device. [Figure 16] FIG. 16 is a schematic diagram showing the positional relationship between a detection region of a sensor region and a detected object. [Figure 17] FIG. 17 is a circuit diagram showing a plurality of partial detection regions of a detection device according to an embodiment. [Figure 18A] FIG. 18A is a cross-sectional view showing a schematic cross-sectional configuration of a sensor region. [Figure 18B] FIG. 18B is a cross-sectional view showing a schematic cross-sectional configuration of a sensor region of a detection device according to a modified example. [Figure 19] FIG. 19 is a timing waveform diagram showing an operation example of a detection device. [Figure 20] FIG. 20 is a timing waveform diagram showing an operation example during a reset period in FIG. 19. [Figure 21] FIG. 21 is a timing waveform diagram showing an operation example during a read period in FIG. 19. [Figure 22] FIG. 22 is a timing waveform diagram showing an operation example of a driving period of one gate line included in a row read period in FIG. 19. [Figure 23] FIG. 23 is an explanatory diagram for explaining the relationship between the driving of a sensor region according to a comparative example and the lighting operation of a light source. [Figure 24] FIG. 24 is an explanatory diagram for explaining the relationship between the driving of the sensor region of the detection device of the present disclosure and the lighting operation of the light source. [Figure 25] FIG. 25 is a plan view schematically showing the relationship between the sensor region of the detection device according to the embodiment and the first light source and the second light source. [Figure 26A] FIG. 26A is a side view of the detection device shown in FIG. 25 as viewed from the first direction. [Figure 26B] FIG. 26B is a side view of the detection device shown in FIG. 25 as viewed from the opposite side of the first direction Dx.

Embodiments for Carrying Out the Invention

[0009] Embodiments (embodiments) for carrying out the present invention will be described in detail while referring to the drawings. The present disclosure is not limited by the content described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and substantially the same ones. Furthermore, the constituent elements described below can be combined as appropriate. Note that the disclosure is merely an example, and those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the present disclosure are naturally included in the scope of the present disclosure. In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present disclosure. Also, in the present disclosure and each figure, the same reference numerals may be assigned to the same elements as those described above with respect to the already shown figures, and detailed descriptions may be omitted as appropriate.

[0010] In this specification and the claims, when expressing the aspect of arranging one structure on another structure, when simply described as "on", unless otherwise specified, it includes both the case of arranging another structure directly on one structure so as to be in contact with it and the case of arranging another structure above one structure via yet another structure.

[0011] (Comparative Example) To facilitate understanding of this disclosure, a comparative example will be described first. Figure 1 shows the main components of a detection device according to the comparative example. As shown in Figure 1, the detection device according to the comparative example comprises a red light source 61R, a green light source 61G, and a light sensor PAA0. In the figure, "R" indicates a red light source, and "G" indicates a green light source. The same applies to the other figures.

[0012] The green light source 61G emits green light. Green light has a wavelength of, for example, 490 nm to 550 nm. The red light source 61R emits red light. Red light has a wavelength of, for example, 640 nm to 770 nm. In other words, the green light source 61G and the red light source 61R emit light of different wavelengths. The light sensor PAA0 detects light. The light sensor PAA0 is provided in common with both the red light source 61R and the green light source 61G. The light sensor PAA0 can detect both red and green light.

[0013] In the comparative example shown in Figure 1, a red light source 61R and a green light source 61G are alternately lit and the light is received by the photosensor PAA0. Figure 2 shows an example of the operation of the detection device shown in Figure 1. In Figure 2, the horizontal axis represents the passage of time, and the vertical axis represents the content of the operation. As shown in Figure 2, in this example, first, the red light source 61R is lit to emit red light, and the photosensor PAA0 detects the red light (period P11). Then, the detection data from the photosensor PAA0 is read out (period P12). Next, the green light source 61G is lit to emit green light, and the photosensor PAA0 detects the green light (period P13). Then, the detection data from the photosensor PAA0 is read out (period P14). Thus, in the comparative examples shown in Figures 1 and 2, the red light source 61R and the green light source 61G, which emit light of different wavelengths, are alternately lit, and data for each is acquired in time division.

[0014] (Main components of the detection device) Figure 3 shows the main components of the detection device of the present disclosure. As shown in Figure 3, the detection device of the present disclosure comprises a red light source 61R, a green light source 61G, an optical sensor PAA1, an optical sensor PAA2, a control circuit 122, and a signal processing circuit 44. The signal processing circuit 44 corresponds to the signal processing unit of the present disclosure.

[0015] The first light source, the green light source 61G, emits green light. The second light source, the red light source 61R, emits red light. In other words, the green light source 61G and the red light source 61R emit light of different wavelengths.

[0016] The control circuit 122 functions as a control unit that causes the red light source 61R and the green light source 61G to emit light. The control circuit 122 causes the green light source 61G and the red light source 61R to emit light simultaneously.

[0017] The first light sensor, light sensor PAA1, detects light. The second light sensor, light sensor PAA2, is provided adjacent to light sensor PAA1. The first light sensor, light sensor PAA1, is provided in a position between the second light sensor, light sensor PAA2, and the first light source, green light source 61G. The second light sensor, light sensor PAA2, is provided in a position between the first light sensor, light sensor PAA1, and the second light source, red light source 61R.

[0018] The signal processing circuit 44 performs a process to acquire blood oxygen saturation based on the values ​​detected by the optical sensor PAA1 and the values ​​detected by the optical sensor PAA2.

[0019] In the detection device shown in Figure 3, green light emitted from the green light source 61G is incident on a living organism (not shown). Red light emitted from the red light source 61R is incident on a living organism (not shown). Light sensors PAA1 and PAA2 detect light that has passed through the living organism (not shown) or light that has been reflected from the living organism (not shown).

[0020] Now, let's consider the case where the detection device shown in Figure 3 is operated in the same way as in Figure 2. Figure 4 is a diagram showing an example of the operation of the detection device shown in Figure 3. In Figure 4, the horizontal axis shows the passage of time, and the vertical axis shows the content of the operation. As shown in Figure 4, when the red light source 61R and the green light source 61G are turned on alternately, first the red light source 61R is turned on to emit red light, and the light sensor PAA1 detects the red light (period P11). Then, the detection data from the light sensor PAA1 is read out (period P12). Next, the green light source 61G is turned on to emit green light, and the light sensor PAA1 detects the green light (period P13). Then, the detection data from the light sensor PAA1 is read out (period P14). In this way, when the red light source 61R and the green light source 61G, which emit light of different wavelengths, are turned on alternately, the data for each is acquired in time division.

[0021] Figure 5 shows the usage status of light sensors PAA1 and PAA2 in the operation example shown in Figure 4. As shown in Figure 5, during periods P11 and P12, the red light source 61R is turned on and the green light source 61G is turned off. Light sensor PAA1 detects the red light and reads the detection data from light sensor PAA1. Also, during periods P13 and P14, the green light source 61G is turned on and the red light source 61R is turned off. Light sensor PAA1 detects the green light and reads the detection data from light sensor PAA1. Therefore, when the red light source 61R and the green light source 61G are turned on alternately, light sensor PAA1 is used from period P11 to P14, and light sensor PAA2 is not used.

[0022] In contrast to the operation example described with reference to Figure 4, the detection device of this disclosure operates as follows. Figure 6 is a diagram showing an example of operation of the detection device of this disclosure. In Figure 6, the horizontal axis represents the passage of time, and the vertical axis represents the content of the operation. As shown in Figure 6, in this example, the red light source 61R and the green light source 61G are turned on simultaneously (period P21). That is, the red light source 61R and the green light source 61G, which emit light of different wavelengths, are turned on simultaneously. Then, detection data from the light sensors PAA1 and PAA2 are read out (period P22). In this way, the red light source 61R and the green light source 61G, which emit light of different wavelengths, are turned on simultaneously, and data is acquired from the light sensors PAA1 and PAA2.

[0023] Figure 7 shows the usage status of light sensors PAA1 and PAA2 in the operation example shown in Figure 6. As shown in Figure 7, the red light source 61R and the green light source 61G are turned on simultaneously during period P21. Then, light sensor PAA1 detects light containing red and green light, and the detection data from light sensor PAA1 is read out. At the same time, light sensor PAA2 detects light containing red and green light, and the detection data from light sensor PAA2 is read out. In other words, from period P21 to P22, light sensors PAA1 and PAA2 are used, and their respective data is acquired.

[0024] Returning to Figure 3, let's focus on the light sensor PAA1. The light sensor PAA1 is positioned so that it is closer to the green light source 61G than to the red light source 61R. The distance from the light sensor PAA1 to the green light source 61G is shorter than the distance from the light sensor PAA1 to the red light source 61R. Therefore, if we consider the green light (G) detected by the light sensor PAA1 to be, for example, 100%, then the red light (R) will be, for example, 50%. In other words, the detected value of red light in the light sensor PAA1 will be about half the detected value of green light.

[0025] Furthermore, let's focus on the light sensor PAA2. The light sensor PAA2 is positioned at a location where the distance from the red light source 61R is shorter than the distance from the green light source 61G. The distance from the light sensor PAA2 to the red light source 61R is shorter than the distance from the light sensor PAA2 to the green light source 61G. Therefore, if we consider the red light (R) detected by the light sensor PAA2 to be, for example, 100%, then the green light (G) will be, for example, 50%. In other words, the detected value of green light in the light sensor PAA2 will be about half the detected value of red light. As described above, the proportion of red light from the red light source 61R and green light from the green light source 61G that reach the light sensors PAA1 and PAA2 is different. It should be noted that red light is known to travel further than green light. As for green light, due to its high attenuation within the body, the component that travels far is small.

[0026] As explained with reference to Figures 2 and 4, when the green light source 61G and the red light source 61R are switched on alternately and data is acquired from each in a time-division manner, the frame rate cannot be increased. Here, the frame rate is the number of times data can be acquired in the time equivalent to one frame. In contrast, as explained with reference to Figure 6, the frame rate for data acquisition can be increased by switching on the red light source 61R and the green light source 61G simultaneously. When data is acquired by switching on both lights simultaneously, the frame rate is doubled compared to acquiring data from each light source in a time-division manner. By increasing the frame rate, blood oxygen saturation SpO2 can be calculated more efficiently.

[0027] When a green light source 61G and a red light source 61R are alternately illuminated and data is acquired in time-division mode, blood oxygen saturation SpO2 is calculated using pulse wave data by equation (1).

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[0028] In equation (1) above, "a" and "b" are predetermined coefficients determined in advance based on measured values. In equation (1), R is defined by the following equation (2).

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[0029] In equation (2) above, AC(Red) is the AC component of the measured value of red light, DC(Red) is the DC component of the measured value of red light, AC(Gr) is the AC component of the measured value of green light, and DC(Gr) is the DC component of the measured value of green light. The AC component includes the pulse wave component.

[0030] Incidentally, sometimes light sensors are arranged vertically and horizontally on a plane to form a detection area for detecting light. Two pixels included in such a detection area may be the two light sensors PAA1 and PAA2 mentioned above. In other words, each pixel functions as a light sensor. As shown in Figure 3, when two light sources are turned on simultaneously and data from two pixels is acquired, the following occurs. That is, if pixel Pix1 and pixel Pix2 are used, blood oxygen saturation SpO2 is calculated using pulse wave data by equation (3).

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[0031] In equation (4) above, AC(Pix1) is the AC component of the measurement of the first pixel, DC(Pix1) is the DC component of the measurement of the first pixel, AC(Pix2) is the AC component of the measurement of the second pixel, and DC(Pix2) is the DC component of the measurement of the second pixel. The AC component includes the pulse wave component.

[0032] The above describes the case where the first and second pixels correspond to two light sensors PAA1 and PAA2, but three or more pixels may be used. Figure 8 shows an example in which 10 pixels are used in the detection device. As shown in Figure 8, in this example, pixels Pix1 to Pix10, a green light source 61G, and a red light source 61R are used. Pixels Pix1 to Pix10 are located between the green light source 61G and the red light source 61R.

[0033] In Figure 8, the green light source 61G and the red light source 61R are turned on simultaneously. As a result, light with a different ratio of green light to red light is detected in each of the pixels Pix1 to Pix10. Therefore, by focusing on any two pixels, SpO2 can be calculated using equations (3) and (4) above. Alternatively, SpO2 can be calculated multiple times by sequentially focusing on two pixels, and the average of these calculation results can be obtained. For example, the first SpO2 can be calculated using pixels Pix1 and Pix9, the second SpO2 using pixels Pix1 and Pix9, the third SpO2 using pixels Pix2 and Pix9, and the fourth SpO2 using pixels Pix2 and Pix10, and the average of the four calculation results can be obtained. Note that if each pixel contains independent noise components, the noise components can be effectively removed by calculating the averaged SpO2.

[0034] The following describes a more specific method for calculating blood oxygen saturation (SpO2) when using multiple pixels. Figure 9 shows an example of calculating SpO2 using four pixels in the detection device. In Figure 9, in addition to the first optical sensor pixel Pix1 and the second optical sensor pixel Pix2, the third optical sensor pixel Pix3 and the fourth optical sensor pixel Pix4 are used. In other words, four pixels are used in Figure 9. Figure 10 shows an example of a combination table when two of the four pixels are combined. Figure 10 shows an example of a combination table when pixel (A) and pixel (B) are combined. This combination table is stored in the memory circuit 46 and referenced by the signal processing circuit 44, as will be described later.

[0035] As shown in Figure 9, this example uses four pixels Pix1, Pix2, Pix3, and Pix4, a green light source 61G, and a red light source 61R. The four pixels Pix1 to Pix4 are positioned between the green light source 61G and the red light source 61R.

[0036] As shown in Figure 10, when calculating blood oxygen saturation SpO21, pixels Pix1 and Pix3 are used. That is, the data from pixel Pix1 and the data from pixel Pix3 are used. Then, blood oxygen saturation SpO21 is calculated using the following equations (5) and (6).

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[0037]

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[0038] As shown in Figure 10, when calculating blood oxygen saturation SpO22, pixels Pix1 and Pix4 are used. That is, the data from pixel Pix1 and the data from pixel Pix4 are used. Then, blood oxygen saturation SpO22 is calculated using the following equations (7) and (8).

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[0039]

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[0040] As shown in Figure 10, when calculating blood oxygen saturation SpO23, pixels Pix2 and Pix3 are used. That is, the data from pixel Pix2 and the data from pixel Pix3 are used. Then, blood oxygen saturation SpO23 is calculated using the following equations (9) and (10).

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[0041]

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[0042] As shown in Figure 10, when calculating blood oxygen saturation SpO24, pixels Pix2 and Pix4 are used. That is, the data from pixel Pix2 and the data from pixel Pix4 are used. Blood oxygen saturation SpO24 is calculated using the following equations (11) and (12).

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[0043]

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[0044] Finally, the average value of the calculated values ​​from equations (5), (7), (9), and (11) above is calculated. That is, the average value of blood oxygen saturation SpO2 is calculated using the following equation (13).

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[0045] In equations (5), (7), (9), and (11) above, the coefficients a1, a2, a3, and a4, and the coefficients b1, b2, b3, and b4 are predetermined coefficients determined in advance based on measured values. Coefficients a1, a2, a3, and a4, and coefficients b1, b2, b3, and b4 will have different values ​​because the mixing ratio of green light from the green light source 61G and red light from the red light source 61R is different. In other words, a different coefficient is used for each combination of pixels. These coefficients are stored in the memory circuit 46 (see Figure 14) as an SpO2 calculation parameter table.

[0046] The process of calculating blood oxygen saturation (SpO2) using multiple pixels as described above, and then calculating their average value, will be explained with reference to Figure 11. Figure 11 is a flowchart showing the process of calculating blood oxygen saturation (SpO2) using multiple pixels and then calculating their average value. This process is mainly performed in the signal processing circuit 44.

[0047] In Figure 11, the control circuit 122 simultaneously lights up the red light source 61R and the green light source 61G and measures the pulse wave data of all pixels (step S101). The signal processing circuit 44 stores the measurement results in the memory circuit 46 (see Figure 14) (step S102). Next, the signal processing circuit 44 refers to the combination table stored in the memory circuit 46 (step S103) and selects two pixels of a predetermined combination (step S104).

[0048] Furthermore, the signal processing circuit 44 refers to a combination-specific SpO2 calculation parameter table for the combination of two pixels selected in step S104 (step S105). The signal processing circuit 44 reads the data of the two pixels selected in step S104 from the storage circuit 46 and uses it to calculate the blood oxygen saturation SpO2 (step S106). The signal processing circuit 44 stores the calculated result of the blood oxygen saturation SpO2 in the storage circuit 46 (step S107).

[0049] Next, the signal processing circuit 44 determines whether or not calculations have been performed for all combinations of pixels (step S108). If the result of the determination in step S108 is that calculations have been performed for all combinations of light sensors (Yes in step S108), the process proceeds to step S109, where the signal processing circuit 44 calculates the average value of blood oxygen saturation SpO2 for all combinations (step S109). The signal processing circuit 44 outputs the calculated blood oxygen saturation SpO2 value (step S110) and terminates the process.

[0050] On the other hand, if the signal processing circuit 44 determines in step S108 that it has not performed calculations for all combinations of the optical sensor (No in step S108), that is, if there are combinations for which calculations have not been performed, it returns to step S103 and continues processing. Through the above processing, it is possible to use multiple pixels to calculate blood oxygen saturation SpO2 for each combination of pixels and to calculate the average value of each calculation result. Note that the data read from the memory circuit 46 in step S106 may be temporarily held in a buffer (not shown), for example, and used again in the next calculation of blood oxygen saturation SpO2. For example, if the data of pixel Pix1 used in the calculation of blood oxygen saturation SpO21 in Figure 10 is held in a buffer, that data can be used again in the next calculation of blood oxygen saturation SpO22. This reduces the processing time for calculations compared to reading the data of two pixels from the memory circuit 46 each time.

[0051] (Variations in arrangement) Figure 12 shows a modified arrangement of the light sensor and light source. As shown in Figure 12, the first light sensor, light sensor PAA1, and the second light sensor, light sensor PAA2, are provided adjacent to each other. In addition, the first light source, a green light source 61G, and the second light source, a red light source 61R, are provided closer to light sensor PAA2 than to light sensor PAA1 and light sensor PAA2, which are provided side by side. In other words, the green light source 61G and the red light source 61R are provided closer to light sensor PAA2 than to light sensor PAA1. In this case, the second light sensor PAA2 is provided in a position sandwiched between light sensor PAA1 and the first light source, the green light source 61G. Also, light sensor PAA2 is provided in a position sandwiched between light sensor PAA1 and the second light source, the red light source 61R. Light sensor PAA1 may be pixel Pix1, and light sensor PAA2 may be pixel Pix2. In Figure 12, the case of light sensor PAA1 and light sensor PAA2 will be explained.

[0052] As described above, if the distance from the red light source 61R to the light sensor is the same as the distance from the green light source 61G to the light sensor, the greater the distance between the red light source 61R and the green light source 61G and the light sensor, the greater the intensity of the light detected by the light sensor, with red light being greater than that of green light. For this reason, the light detected by the light sensor PAA2, which is located close to the red light source 61R and the green light source 61G, is, for example, 100% green light (G) and 100% red light (R). In contrast, the light detected by the light sensor PAA1, which is located far from the red light source 61R and the green light source 61G, is, for example, 30% green light (G) and 70% red light (R). Thus, even if the light sensors are located at the same distance from the red light source 61R and the green light source 61G, the ratio of green light (G) and red light (R) components in the light detected by the two light sensors will not be the same. Therefore, even when the light source and light sensor are arranged as shown in Figure 12, the blood oxygen saturation SpO2 value can be calculated based on the value detected by the light sensor by simultaneously illuminating the red light source 61R and the green light source 61G. In this case, the blood oxygen saturation SpO2 value can be calculated by using equations (1) and (2) above and predetermining the coefficients "a" and "b" based on measured values.

[0053] As mentioned above, optical sensors can be arranged vertically and horizontally on a plane to form a detection area for detecting light. The following describes in more detail an embodiment using such a detection area.

[0054] Figure 13 is a plan view showing a detection device according to an embodiment. As shown in Figure 13, the detection device 1 includes a sensor substrate 21, a sensor area 10, a gate line drive circuit 15, a signal line selection circuit 16, a detection circuit 48, a control circuit 122, a power supply circuit 123, a plurality of first light sources 61, and a plurality of second light sources 62. The first light sources 61 correspond to a green light source 61G, and the first light sources 62 correspond to a red light source 61R. Two pixels included in the sensor area 10, for example PixA, correspond to the optical sensors PAA1 and PAA2 in Figure 3. Ten pixels included in the sensor area 10, for example PixB, correspond to pixels Pix1 to Pix10 in Figure 8. Four pixels included in the sensor area 10, for example PixC, correspond to pixels Pix1 to Pix4 in Figure 9. Figure 13 shows an example in which a plurality of first light sources 61 are provided on the first light source substrate 51 and a plurality of second light sources 62 are provided on the second light source substrate 52. However, the arrangement of the first light sources 61 and second light sources 62 shown in Figure 13 is merely an example and can be changed as appropriate. For example, as explained with reference to Figure 12, the first light sources 61 and second light sources 62 may be arranged on the first light source substrate 51.

[0055] The detection device 1 is electrically connected to the host 200. The host 200 is, for example, a higher-level control device of equipment (not shown) to which the detection device 1 is applied. The host 200 performs predetermined biological information acquisition processing based on the data output from the detection device 1.

[0056] The control board 121 is electrically connected to the sensor substrate 21 via a flexible printed circuit board 71. The flexible printed circuit board 71 is provided with a detection circuit 48. The control board 121 is provided with a control circuit 122, a power supply circuit 123, and an output circuit 126.

[0057] The control circuit 122 is, for example, a control integrated circuit (IC) that outputs logic control signals. The control circuit 122 may also be a programmable logic device (PLD), such as an FPGA (Field Programmable Gate Array).

[0058] The control circuit 122 supplies control signals to the sensor area 10, the gate line drive circuit 15, and the signal line selection circuit 16 to control the detection operation of the sensor area 10. The control circuit 122 also supplies control signals to the first light source 61 and the second light source 62 to control whether the first light source 61 and the second light source 62 are lit or not.

[0059] The power supply circuit 123 supplies voltage signals such as the sensor power supply potential VDDSNS (see Figure 17) to the sensor area 10, the gate line drive circuit 15, and the signal line selection circuit 16. The power supply circuit 123 also supplies power supply voltage to the first light source 61 and the second light source 62.

[0060] The output circuit 126 is, for example, a USB controller IC, which controls communication between the control circuit 122 and the host 200.

[0061] The sensor substrate 21 has a detection region AA and a peripheral region GA. The detection region AA is the region where the sensor region 10 is provided with multiple optical sensors PD (see Figure 17). The peripheral region GA is the region between the outer periphery of the detection region AA and the edge of the sensor substrate 21, and is a region where no optical sensors PD are provided.

[0062] The gate line drive circuit 15 and the signal line selection circuit 16 are provided in the peripheral region GA. Specifically, the gate line drive circuit 15 is provided in the region of the peripheral region GA that extends along the second direction Dy. The signal line selection circuit 16 is provided in the region of the peripheral region GA that extends along the first direction Dx, and is provided between the sensor region 10 and the detection circuit 48.

[0063] The first direction Dx is a single direction in a plane parallel to the sensor substrate 21. The second direction Dy is a single direction in a plane parallel to the sensor substrate 21 and is perpendicular to the first direction Dx. The second direction Dy may intersect the first direction Dx without being perpendicular to it. The third direction Dz is perpendicular to both the first direction Dx and the second direction Dy and is the normal direction to the sensor substrate 21.

[0064] Multiple first light sources 61 are provided on the first light source substrate 51 and are arranged along the second direction Dy. Multiple second light sources 62 are provided on the second light source substrate 52 and are arranged along the second direction Dy. The first light source substrate 51 and the second light source substrate 52 are electrically connected to the control circuit 122 and the power supply circuit 123, respectively, via terminals 124 and 125 provided on the control board 121.

[0065] Multiple first light sources 61 and multiple second light sources 62 can be, for example, inorganic LEDs (Light Emitting Diodes) or organic ELs (OLEDs). Each of the multiple first light sources 61 and multiple second light sources 62 emits first and second light of different wavelengths.

[0066] The first light emitted from the first light source 61 is reflected by the surface of the object to be detected, such as the subject's finger Fg (see Figure 25) or wrist, and enters the sensor area 10. This allows the sensor area 10 to detect fingerprints by detecting the shape of the surface irregularities of the finger Fg, etc. The second light emitted from the second light source 62 is reflected by the inside of the finger Fg, etc., or passes through the finger Fg, etc., and enters the sensor area 10. This allows the sensor area 10 to detect biological information inside the subject's finger or wrist, etc. This biological information includes, for example, the subject's pulse wave, pulse rate, and vascular image. That is, the detection device 1 may be configured as a fingerprint detection device for detecting fingerprints, or as a vein detection device for detecting vascular patterns such as veins.

[0067] The first light has a wavelength between 490 nm and 550 nm, and the second light has a wavelength between 640 nm and 770 nm. In this case, the first light is, for example, green visible light (green light), and the second light is, for example, red visible light (red light). Based on the first light emitted from the first light source 61 and the second light emitted from the second light source 62, the sensor area 10 can detect blood oxygen concentration in addition to pulse waves, pulse rate, and vascular images as information about the living body. Thus, the detection device 1 has a first light source 61 and a plurality of second light sources 62, and by performing detection based on the first light and detection based on the second light, it can detect various information about the living body.

[0068] Figure 14 is a block diagram showing an example configuration of a detection device according to an embodiment. As shown in Figure 14, the detection device 1 further includes a detection control circuit 11 and a detection circuit 40.

[0069] The sensor region 10 has multiple photosensors PD. The photosensors PD in the sensor region 10 are organic photodiodes (OPDs), and they output an electrical signal corresponding to the irradiated light as a detection signal Vdet to the signal line selection circuit 16. The sensor region 10 also performs detection according to the gate drive signal Vgcl supplied from the gate line drive circuit 15.

[0070] The detection control circuit 11 is a circuit that supplies control signals to the gate line drive circuit 15, the signal line selection circuit 16, and the detection circuit 40, respectively, and controls their operation. The detection control circuit 11 supplies various control signals such as the start signal STV, the clock signal CK, and the reset signal RST1 to the gate line drive circuit 15. The detection control circuit 11 also supplies various control signals such as the selection signal ASW to the signal line selection circuit 16. Furthermore, the detection control circuit 11 supplies various control signals to the first light source 61 and the second light source 62 to control their illumination and de-illumination.

[0071] The gate line drive circuit 15 is a circuit that drives multiple gate lines GCL (see Figure 15) based on various control signals. The gate line drive circuit 15 sequentially or simultaneously selects multiple gate lines GCL and supplies a gate drive signal Vgcl to the selected gate lines GCL. As a result, the gate line drive circuit 15 selects multiple optical sensors PD connected to the gate lines GCL.

[0072] The signal line selection circuit 16 is a switch circuit that sequentially or simultaneously selects multiple signal lines SGL (see Figure 15). The signal line selection circuit 16 is, for example, a multiplexer. Based on the selection signal ASW supplied from the detection control circuit 11, the signal line selection circuit 16 electrically connects the selected signal line SGL to the detection circuit 48. As a result, the signal line selection circuit 16 outputs the detection signal Vdet of the optical sensor PD to the detection circuit 40.

[0073] The detection circuit 40 comprises a detection circuit 48, a signal processing circuit 44, a memory circuit 46, and a detection timing control circuit 47. The detection timing control circuit 47 controls the detection circuit 48 and the signal processing circuit 44 to operate synchronously based on a control signal supplied from the detection control circuit 11.

[0074] The detection circuit 48 generates detection values ​​for each optical sensor PD based on the detection signals output from each optical sensor PD in the sensor area 10. The detection circuit 48 is, for example, an analog front-end circuit (AFE).

[0075] The detection circuit 48 is a signal processing circuit that has at least the functions of a detection signal amplification circuit 42 and an A / D conversion circuit 43. The detection signal amplification circuit 42 amplifies the detection signal Vdet. The A / D conversion circuit 43 converts the analog signal output from the detection signal amplification circuit 42 into a digital signal.

[0076] In this disclosure, the signal processing circuit 44 and the memory circuit 46 are included in the control circuit 122.

[0077] The signal processing circuit 44 acquires biological data for generating information about a living organism based on the detection values ​​of each optical sensor PD output from the detection circuit 48. In this disclosure, the information about a living organism includes pulse waves acquired by green light and red light.

[0078] The memory circuit 46 temporarily stores the signals processed by the signal processing circuit 44. In this disclosure, the memory circuit 46 also stores the biometric data acquisition area and various setting information set in the biometric data acquisition area setting processing flow described later when the signal processing circuit 44 acquires biometric data. The memory circuit 46 may include, for example, RAM (Random Access Memory), ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), etc. The memory circuit 46 may also be a register circuit, etc.

[0079] Next, an example of the circuit configuration of the detection device 1 will be described. Figure 15 is a circuit diagram showing the detection device. As shown in Figure 15, the sensor area 10 has a plurality of partial detection areas PAA arranged in a matrix. Each of the plurality of partial detection areas PAA is provided with an optical sensor PD.

[0080] The gate line GCL extends in the first direction Dx and is connected to multiple partial detection regions PAA arranged in the first direction Dx. Furthermore, multiple gate lines GCL(1), GCL(2), ..., GCL(8) are arranged in the second direction Dy and are each connected to the gate line drive circuit 15. In the following explanation, when it is not necessary to distinguish between multiple gate lines GCL(1), GCL(2), ..., GCL(8), they will simply be referred to as gate line GCL. Also, while Figure 15 shows eight gate lines GCL for clarity, this is merely an example, and there may be M gate lines GCL (where M is a natural number, e.g., M=256) arranged.

[0081] The signal line SGL extends in the second direction Dy and is connected to the optical sensor PD of multiple partial detection regions PAA arranged in the second direction Dy. Furthermore, the multiple signal lines SGL(1), SGL(2), ..., SGL(12) are arranged in the first direction Dx and are connected to the signal line selection circuit 16 and the reset circuit 17, respectively. In the following description, when it is not necessary to distinguish between the multiple signal lines SGL(1), SGL(2), ..., SGL(12), they will simply be referred to as signal line SGL.

[0082] Furthermore, for the sake of clarity, 12 signal lines SGL are shown, but this is merely an example, and there may be N signal lines SGL arranged (N is a natural number, for example, N=252). Also, in Figure 15, a sensor area 10 is provided between the signal line selection circuit 16 and the reset circuit 17. However, it is not limited to this, and the signal line selection circuit 16 and the reset circuit 17 may be connected to the ends of the signal lines SGL in the same direction, respectively.

[0083] The gate line drive circuit 15 receives various control signals such as the start signal STV, clock signal CK, and reset signal RST1 from the control circuit 122 (see Figure 13). Based on the various control signals, the gate line drive circuit 15 sequentially selects a plurality of gate lines GCL(1), GCL(2), ..., GCL(8) in a time-division multiplexing manner. The gate line drive circuit 15 supplies a gate drive signal Vgcl to the selected gate line GCL. As a result, the gate drive signal Vgcl is supplied to a plurality of first switching elements Tr connected to the gate line GCL, and a plurality of partial detection regions PAA arranged in the first direction Dx are selected as detection targets.

[0084] Furthermore, the gate line drive circuit 15 may perform different drives for each detection mode of fingerprint detection and different types of biological information (pulse wave, pulse rate, vascular image, blood oxygen concentration, etc., hereinafter also simply referred to as "biological information"). For example, the gate line drive circuit 15 may drive multiple gate lines GCLs together.

[0085] Specifically, the gate line drive circuit 15 simultaneously selects a predetermined number of gate lines GCL(1), GCL(2), ..., GCL(8) based on a control signal. For example, the gate line drive circuit 15 simultaneously selects gate line GCL(6) from the six gate lines GCL(1) and supplies a gate drive signal Vgcl. The gate line drive circuit 15 supplies the gate drive signal Vgcl to multiple first switching elements Tr via the six selected gate lines GCL. As a result, block units PAG1 and PAG2, each containing multiple partial detection regions PAA arranged in the first direction Dx and the second direction Dy, are selected as detection targets. The gate line drive circuit 15 drives a predetermined number of gate lines GCL in a bundle and sequentially supplies a gate drive signal Vgcl to each predetermined number of gate lines GCL.

[0086] The signal line selection circuit 16 has multiple selection signal lines Lsel, multiple output signal lines Lout, and third switching elements TrS. Each of the multiple third switching elements TrS is provided corresponding to one of the multiple signal lines SGL. Six signal lines SGL(1), SGL(2), ..., SGL(6) are connected to a common output signal line Lout1. Six signal lines SGL(7), SGL(8), ..., SGL(12) are connected to a common output signal line Lout2. Output signal lines Lout1 and Lout2 are each connected to a detection circuit 48.

[0087] Here, signal lines SGL(1), SGL(2), ..., SGL(6) are designated as the first signal line block, and signal lines SGL(7), SGL(8), ..., SGL(12) are designated as the second signal line block. Multiple selection signal lines Lsel are each connected to the gate of a third switching element TrS contained in one signal line block. In addition, one selection signal line Lsel is connected to the gate of a third switching element TrS in multiple signal line blocks.

[0088] Specifically, the selection signal lines Lsel1, Lsel2, ..., Lsel6 are connected to the third switching elements TrS corresponding to the signal lines SGL(1), SGL(2), ..., SGL(6), respectively. In addition, selection signal line Lsel1 is connected to the third switching element TrS corresponding to signal line SGL(1) and the third switching element TrS corresponding to signal line SGL(7). Selection signal line Lsel2 is connected to the third switching element TrS corresponding to signal line SGL(2) and the third switching element TrS corresponding to signal line SGL(8).

[0089] The control circuit 122 (see Figure 13) sequentially supplies the selection signal ASW to the selection signal line Lsel. As a result, the signal line selection circuit 16, through the operation of the third switching element TrS, sequentially selects the signal line SGL in a time-division manner within one signal line block. The signal line selection circuit 16 also selects one signal line SGL in each of multiple signal line blocks. With this configuration, the detection device 1 can reduce the number of integrated circuits (ICs) including the detection circuit 48, or the number of terminals of the ICs.

[0090] The signal line selection circuit 16 may also bundle multiple signal lines SGL and connect them to the detection circuit 48. Specifically, the control circuit 122 (see Figure 13) simultaneously supplies the selection signal ASW to the selected signal line Lsel. The signal line selection circuit 16, through the operation of the third switching element TrS, selects multiple signal lines SGL (for example, six signal lines SGL) in one signal line block and connects the multiple signal lines SGL to the detection circuit 48. As a result, the signals detected in the block units PAG1 and PAG2 are output to the detection circuit 48. In this case, the signals from multiple partial detection areas PAA (optical sensor PD) included in the block units PAG1 and PAG2 are integrated and output to the detection circuit 48.

[0091] The operation of the gate line drive circuit 15 and the signal line selection circuit 16 allows detection to be performed for each block unit PAG1 and PAG2, thereby improving the intensity of the detection signal Vdet obtained in a single detection, and thus improving the sensor sensitivity.

[0092] In this disclosure, the detection device 1 can change the number of partial detection areas PAA (optical sensor PD) included in block units PAG1 and PAG2. This allows the resolution per inch (ppi (pixels per inch) value, hereinafter referred to as "resolution") to be set according to the information to be acquired.

[0093] For example, the number of partial detection areas PAA (optical sensor PD) included in block units PAG1 and PAG2 is relatively reduced. This results in a longer detection time and a lower frame rate (e.g., 20fps or less), but enables high-resolution detection (e.g., 300ppi or more). Hereinafter, the mode that performs low-frame-rate and high-resolution detection will be referred to as "Mode 1". By selecting Mode 1, which performs low-frame-rate and high-resolution detection, it is possible to acquire fingerprints on the surface of a finger with high resolution, for example.

[0094] Furthermore, for example, the number of partial detection areas PAA (optical sensor PD) included in block units PAG1 and PAG2 is relatively increased. This results in lower resolution (e.g., 50 ppi or less), but allows for detection at a high frame rate (e.g., 100 fps or more), enabling repeated detection in a short time within a single frame. Hereinafter, the mode that performs high frame rate and low resolution detection will be referred to as the "second mode." By selecting the second mode, which performs high frame rate and low resolution detection, it is possible to accurately detect, for example, the temporal changes in pulse waves. In addition, by using pulse waves acquired at a higher frame rate (e.g., 1000 fps or more) in this second mode, it becomes possible to calculate pulse wave propagation velocity and blood pressure, etc.

[0095] Furthermore, for example, when acquiring vascular images (vein patterns), the number of partial detection areas PAA (optical sensor PD) included in block units PAG1 and PAG2 is set to an intermediate value between the first and second modes. This allows detection to be performed at a medium frame rate (e.g., greater than 20fps but less than 100fps) that is higher than the first mode but lower than the second mode, and at a medium resolution (e.g., greater than 50ppi but less than 300ppi) that is lower than the first mode but higher than the second mode. Hereinafter, the mode that performs detection at a medium frame rate and medium resolution will be referred to as the "third mode." This third mode, which performs detection at a medium frame rate and medium resolution, is suitable for acquiring vascular patterns such as veins, for example.

[0096] As shown in Figure 15, the reset circuit 17 includes a reference signal line Lvr, a reset signal line Lrst, and a fourth switching element TrR. The fourth switching element TrR is provided corresponding to a plurality of signal lines SGL. The reference signal line Lvr is connected to either the source or the drain of the plurality of fourth switching elements TrR. The reset signal line Lrst is connected to the gate of the plurality of fourth switching elements TrR.

[0097] The control circuit 122 supplies the reset signal RST2 to the reset signal line Lrst. This turns on multiple fourth switching elements TrR, and multiple signal lines SGL are electrically connected to the reference signal line Lvr. The power supply circuit 123 supplies the reference signal COM to the reference signal line Lvr. This supplies the reference signal COM to multiple capacitive elements Ca (see Figure 17) included in the multiple partial detection regions PAA.

[0098] Figure 16 is a schematic diagram showing the positional relationship between the detection area of ​​the sensor region and the object to be detected. In Figure 16, the subject's finger Fg is used as an example of the object to be detected. The finger Fg is placed on the detection area AA. The finger Fg is placed so as to cover a portion of the detection area AA. Note that the object to be detected is not limited to the subject's finger Fg; it could also be the wrist or another object.

[0099] Figure 17 is a circuit diagram showing multiple partial detection regions of the detection device according to the embodiment. Figure 17 also shows the circuit configuration of the detection circuit 48. As shown in Figure 17, the partial detection region PAA includes a photosensor PD, a capacitive element Ca, and a first switching element Tr1. The capacitive element Ca is a capacitance (sensor capacitance) formed in the photosensor PD and is equivalently connected in parallel with the photosensor PD. Furthermore, the signal line capacitance Cc is a parasitic capacitance formed in the signal line SGL and is equivalently formed between the signal line SGL and one end of the anode of the photosensor PD and the capacitive element Ca.

[0100] Figure 17 shows two gate lines GCL(m) and GCL(m+1) aligned in the second direction Dy, among multiple gate lines GCL. It also shows two signal lines SGL(n) and SGL(n+1) aligned in the first direction Dx, among multiple signal lines SGL. The partial detection region PAA is the region enclosed by the gate lines GCL and the signal lines SGL.

[0101] The first switching element Tr is provided in accordance with the photosensor PD. The first switching element Tr is composed of a thin-film transistor, and in this example, it is composed of an n-channel MOS (Metal Oxide Semiconductor) type TFT (Thin Film Transistor).

[0102] The gates of the first switching elements Tr belonging to multiple partial detection regions PAA aligned in the first direction Dx are connected to the gate line GCL. The sources of the first switching elements Tr belonging to multiple partial detection regions PAA aligned in the second direction Dy are connected to the signal line SGL. The drains of the first switching elements Tr are connected to the cathode and capacitive element Ca of the photosensor PD.

[0103] The anode of the optical sensor PD is supplied with the sensor power signal VDDSNS from the power supply circuit 123. In addition, the signal line SGL and the capacitive element Ca are supplied with a reference signal COM from the power supply circuit 123, which becomes the initial potential of the signal line SGL and the capacitive element Ca.

[0104] When light is shone onto the partial detection area PAA, a current corresponding to the amount of light flows through the photosensor PD, causing charge to accumulate in the capacitive element Ca. When the first switching element Tr is turned on, a current flows through the signal line SGL according to the charge accumulated in the capacitive element Ca. The signal line SGL is connected to the detection circuit 48 via the third switching element TrS of the signal line selection circuit 16. As a result, the detection device 1 can detect a signal corresponding to the amount of light shone onto the photosensor PD for each partial detection area PAA, or for each block unit PAG1, PAG2. The initial settings for the light intensity of the first light source 61 and the second light source 62 will be described later.

[0105] The detection circuit 48 is connected to the signal line SGL when the switch SSW is turned on during the readout period Pdet (see Figure 19). The detection signal amplification circuit 42 of the detection circuit 48 converts the current fluctuations supplied from the signal line SGL into voltage fluctuations and amplifies them. A reference potential (Vref) with a fixed potential is input to the non-inverting input (+) of the detection signal amplification circuit 42, and the signal line SGL is connected to the inverting input terminal (-). In this embodiment, the same signal as the reference signal COM is input as the reference potential (Vref) voltage. The detection signal amplification circuit 42 also has a capacitive element Cb and a reset switch RSW. During the reset period Prst (see Figure 19), the reset switch RSW is turned on, and the charge of the capacitive element Cb is reset.

[0106] Next, the configuration of the optical sensor PD will be described. Figure 18A is a cross-sectional view showing the schematic cross-sectional configuration of the sensor region. As shown in Figure 18A, the sensor region 10 comprises a sensor substrate 21, a TFT layer 22, an insulating layer 23, an optical sensor PD, and insulating layers 24a, 24b, 24c, and 25. The sensor substrate 21 is an insulating substrate, and for example, glass or resin material can be used. The sensor substrate 21 is not limited to a flat plate shape and may have a curved surface. In this case, the sensor substrate 21 may be a film-like resin. The sensor substrate 21 has a first surface and a second surface opposite to the first surface. On the first surface, the TFT layer 22, insulating layer 23, optical sensor PD, and insulating layers 24 and 25 are laminated in that order.

[0107] The TFT layer 22 is provided with circuits such as the gate line drive circuit 15 and the signal line selection circuit 16 described above. The TFT layer 22 is also provided with TFTs (Thin Film Transistors) such as the first switching element Tr, and various wirings such as the gate line GCL and the signal line SGL. The sensor substrate 21 and the TFT layer 22 are a drive circuit board that drives the sensor for each predetermined detection area, and are also called a backplane or array substrate.

[0108] The insulating layer 23 is an organic insulating layer and is provided on top of the TFT layer 22. The insulating layer 23 is a planarizing layer that flattens the irregularities formed by the first switching element Tr and various conductive layers on the TFT layer 22.

[0109] The optical sensor PD is provided on the insulating layer 23. The optical sensor PD has a lower electrode 35, a semiconductor layer 31, and an upper electrode 34, which are stacked in this order.

[0110] The lower electrode 35 is provided on the insulating layer 23 and is electrically connected to the first switching element Tr of the TFT layer 22 via a contact hole H1. The lower electrode 35 is the cathode of the optical sensor PD and is the electrode for reading out the detection signal Vdet. For example, the lower electrode 35 can be made of a metallic material such as molybdenum (Mo) or aluminum (Al). Alternatively, the lower electrode 35 may be a laminated film in which multiple layers of these metallic materials are stacked. The lower electrode 35 may also be made of a transparent conductive material such as ITO (Indium Tin Oxide).

[0111] The semiconductor layer 31 is amorphous silicon (a-Si). The semiconductor layer 31 includes an i-type semiconductor layer 32a, a p-type semiconductor layer 32b, and an n-type semiconductor layer 32c. The i-type semiconductor layer 32a, the p-type semiconductor layer 32b, and the n-type semiconductor layer 32c are specific examples of photoelectric conversion elements. In Figure 18A, the n-type semiconductor layer 32c, the i-type semiconductor layer 32a, and the p-type semiconductor layer 32b are stacked in the order perpendicular to the surface of the sensor substrate 21. However, the opposite configuration is also possible, i.e., the p-type semiconductor layer 32b, the i-type semiconductor layer 32a, and the n-type semiconductor layer 32c are stacked in that order. The semiconductor layer 31 may also be a photoelectric conversion element made of an organic semiconductor.

[0112] The n-type semiconductor layer 32c is formed by doping a-Si with impurities to create an n+ region. The p-type semiconductor layer 32b is formed by doping a-Si with impurities to create a p+ region. The i-type semiconductor layer 32a is, for example, an undoped intrinsic semiconductor and has lower conductivity than the p-type semiconductor layer 32b and the n-type semiconductor layer 32c.

[0113] The upper electrode 34 is the anode of the photosensor PD and is an electrode for supplying the power signal VDDSNS to the photoelectric conversion layer. The upper electrode 34 is a translucent conductive layer such as ITO and is provided in common for all photosensor PDs.

[0114] Insulating layers 24a and 24b are provided on top of insulating layer 23. Insulating layer 24a covers the periphery of the upper electrode 34 and has an opening in a position that overlaps with the upper electrode 34. The connecting wiring 36 is connected to the upper electrode 34 in the portion of the upper electrode 34 where insulating layer 24a is not provided. Insulating layer 24b is provided on top of insulating layer 24a, covering the upper electrode 34 and the connecting wiring 36. An insulating layer 24c, which is a flattening layer, is provided on top of insulating layer 24b. An insulating layer 25 is provided on top of insulating layer 24c. However, insulating layer 25 is optional.

[0115] Figure 18B is a cross-sectional view showing a schematic cross-sectional configuration of the sensor area of ​​a modified detection device. As shown in Figure 18B, in the modified detection device 1A, the optical sensor PDA is provided on an insulating layer 23a. The insulating layer 23a is an inorganic insulating layer provided covering the insulating layer 23, and is formed of, for example, silicon nitride (SiN). The optical sensor PDA has a photoelectric conversion layer 31A, a lower electrode 35 (cathode electrode), and an upper electrode 34 (anode electrode). In a direction perpendicular to the first surface S1 of the sensor substrate 21, the lower electrode 35, the photoelectric conversion layer 31A, and the upper electrode 34 are stacked in that order.

[0116] The photoelectric conversion layer 31A changes its properties (e.g., voltage-current characteristics and resistance) depending on the light it is irradiated with. Organic materials are used as the material for the photoelectric conversion layer 31A. Specifically, for example, low molecular weight organic materials such as C60 (fullerene), PCBM (phenyl C61-butyric acid methyl ester), CuPc (copper phthalocyanine), F16CuPc (fluorinated copper phthalocyanine), rubrene (5,6,11,12-tetraphenyltetracene), and PDI (derivative of perylene) can be used as the photoelectric conversion layer 31A.

[0117] The photoelectric conversion layer 31A can be formed by vapor deposition (Dry Process) using these low-molecular-weight organic materials. In this case, the photoelectric conversion layer 31A may be, for example, a laminated film of CuPc and F16CuPc, or a laminated film of rubrene and C60. The photoelectric conversion layer 31A can also be formed by coating (Wet Process). In this case, the photoelectric conversion layer 31A uses a material that combines the low-molecular-weight organic material and polymer organic material described above. As the polymer organic material, for example, P3HT (poly(3-hexylthiophene)), F8BT (F8-alt-benzothiadiazole), etc. can be used. The photoelectric conversion layer 31A can be a film in which P3HT and PCBM are mixed, or a film in which F8BT and PDI are mixed.

[0118] The lower electrode 35 and the upper electrode 34 face each other with the photoelectric conversion layer 31A in between. The upper electrode 34 is made of a transparent conductive material such as ITO (Indium Tin Oxide). The lower electrode 35 is made of a metallic material such as silver (Ag) or aluminum (Al). Alternatively, the lower electrode 35 may be made of an alloy material containing at least one of these metallic materials.

[0119] By controlling the film thickness of the lower electrode 35, the lower electrode 35 can be formed as a semi-transparent electrode with light transmission. For example, by forming the lower electrode 35 with a 10 nm thick Ag thin film, it can have about 60% light transmission. In this case, the optical sensor PDA can detect both light irradiated from both sides of the sensor substrate 21, for example, light L1 irradiated from the first surface S1 and light irradiated from the second surface S2.

[0120] Although not shown in Figure 18B, an insulating layer 24 may be provided covering the upper electrode 34. The insulating layer is a passivation film and is provided to protect the optical sensor PDA.

[0121] As shown in Figure 18B, the TFT layer 22 is provided with a first switching element Tr that is electrically connected to the optical sensor PDA. The first switching element Tr has a semiconductor layer 81, a source electrode 82, a drain electrode 83, and gate electrodes 84 and 85. The lower electrode 35 of the optical sensor PDA is electrically connected to the drain electrode 83 of the first switching element Tr via contact holes H11 provided in the insulating layers 23 and 23a.

[0122] The first switching element Tr is a so-called dual-gate structure in which gate electrodes 84 and 85 are provided on both the upper and lower sides of the semiconductor layer 81. However, it is not limited to this, and the first switching element Tr may also have a top-gate structure or a bottom-gate structure.

[0123] Figure 18B schematically shows the second switching element TrA and terminal portion 72 provided in the peripheral region GA. The second switching element TrA is, for example, a switching element provided in the gate line driving circuit 15 (see Figure 13). The second switching element TrA has a semiconductor layer 86, a source electrode 87, a drain electrode 88, and a gate electrode 89. The second switching element TrA has a so-called top-gate structure in which the gate electrode 89 is provided on the upper side of the semiconductor layer 86. Below the semiconductor layer 86, a light-shielding layer 90 is provided between the semiconductor layer 86 and the sensor substrate 21. However, it is not limited to this, and the second switching element TrA may also have a bottom-gate structure or a dual-gate structure.

[0124] The semiconductor layer 81 of the first switching element Tr and the semiconductor layer 86 of the second switching element TrA are provided on different layers. The semiconductor layer 81 of the first switching element Tr is, for example, an oxide semiconductor. The semiconductor layer 86 of the second switching element TrA is, for example, polysilicon.

[0125] Next, an example of the operation of the detection device 1 will be described. Figure 19 is a timing waveform diagram showing an example of the operation of the detection device. Figure 20 is a timing waveform diagram showing an example of the operation of the reset period in Figure 19. Figure 21 is a timing waveform diagram showing an example of the operation of the readout period in Figure 19. Figure 22 is a timing waveform diagram showing an example of the operation of the drive period of one gate line included in the row readout period VR in Figure 19. Figures 23 and 24 are explanatory diagrams to explain the relationship between the drive of the sensor area of ​​the detection device and the lighting operation of the light source.

[0126] As shown in Figure 19, the detection device 1 has a reset period Pst, an exposure period Pex, and a readout period Pdet. The power supply circuit 123 supplies the sensor power supply signal VDDSNS to the anode of the photosensor PD over the reset period Pst, the exposure period Pex, and the readout period Pdet. The sensor power supply signal VDDSNS is a signal that applies a reverse bias between the anode and cathode of the photosensor PD. For example, although the cathode of the photosensor PD has a reference signal COM of approximately 0.75V, by applying the sensor power supply signal VDDSNS of approximately -1.25V to the anode, the anode-cathode is reverse-biased to approximately 2.0V. The control circuit 122 sets the reset signal RST2 to "H" and then supplies the start signal STV and clock signal CK to the gate line drive circuit 15, starting the reset period Pst. During the reset period Pst, the control circuit 122 supplies the reference signal COM to the reset circuit 17 and turns on the fourth switching element TrR for supplying the reset voltage with the reset signal RST2. As a result, a reference signal COM is supplied to each signal line SGL as a reset voltage. The reference signal COM is set to, for example, 0.75V.

[0127] During the reset period PRST, the gate line drive circuit 15 sequentially selects gate lines GCL based on the start signal STV, the clock signal CK, and the reset signal RST1. The gate line drive circuit 15 sequentially supplies gate drive signals Vgcl{Vgcl(1) to Vgcl(M)} to the gate lines GCL. The gate drive signals Vgcl have a pulsed waveform with a high-level voltage, which is the power supply voltage VDD, and a low-level voltage, which is the power supply voltage VSS. In Figure 19, M gate lines GCL (e.g., M=256) are provided, and gate drive signals Vgcl(1), ..., Vgcl(M) are sequentially supplied to each gate line GCL, causing multiple first switching elements Tr to conduct sequentially in each row, and a reset voltage is supplied. For example, the voltage of the reference signal COM, 0.75V, is supplied as the reset voltage.

[0128] Specifically, as shown in Figure 20, the gate line drive circuit 15 supplies a gate drive signal Vgcl(1) with a high-level voltage (power supply voltage VDD) to the gate line GCL(1) during period V(1). The control circuit 122 supplies one of the selection signals ASW1, ..., ASW6 (selection signal ASW1 in Figure 20) to the signal line selection circuit 16 during the period when the gate drive signal Vgcl(1) is at a high-level voltage (power supply voltage VDD). As a result, the signal line SGL of the partial detection region PAA selected by the gate drive signal Vgcl(1) is connected to the detection circuit 48. Consequently, a reset voltage (reference signal COM) is also supplied to the connection wiring between the third switching element TrS and the detection circuit 48.

[0129] Similarly, the gate line drive circuit 15 supplies high-level voltage gate drive signals Vgcl(2), ..., Vgcl(M-1), and Vgcl(M) to the gate lines GCL(2), ..., GCL(M-1), and GCL(M), respectively, during periods V(2), ..., V(M-1), and V(M).

[0130] As a result, during the reset period Prst, all capacitive elements Ca in the partial detection region PAA are sequentially electrically connected to the signal line SGL, and the reference signal COM is supplied. Consequently, the capacitance of the capacitive elements Ca is reset. It is also possible to reset the capacitance of only some of the capacitive elements Ca in the partial detection region PAA by partially selecting the gate line and the signal line SGL.

[0131] Examples of exposure timing include the gate line non-selection exposure control method and the continuous exposure control method. In the gate line non-selection exposure control method, gate drive signals {Vgcl(1)~(M)} are sequentially supplied to all gate lines GCL connected to the target optical sensor PD, and a reset voltage is supplied to all target optical sensor PDs. Subsequently, when all gate lines GCL connected to the target optical sensor PD reach a low voltage (the first switching element Tr is off), exposure begins, and exposure is performed during the exposure period Pex. When exposure is complete, as described above, gate drive signals {Vgcl(1)~(M)} are sequentially supplied to the gate lines GCL connected to the target optical sensor PD, and reading is performed during the readout period Pdet. In the continuous exposure control method, it is also possible to control exposure during the reset period Prst and the readout period Pdet (continuous exposure control). In this case, the exposure period Pex(1) begins after the gate drive signal Vgcl(1) is supplied to the gate lines GCL during the reset period Prst. Here, the exposure period Pex{(1)···(M)} is defined as the period during which the capacitive element Ca is charged from the photosensor PD. During the reset period Pst, the charge charged in the capacitive element Ca is reversed by light irradiation, causing a current to flow from the photosensor PD (from cathode to anode), and the potential difference of the capacitive element Ca decreases. Note that the actual exposure periods Pex(1), ..., Pex(M) in the partial detection region PAA corresponding to each gate line GCL have different start and end timings. Each exposure period Pex(1), ..., Pex(M) starts during the reset period Pst when the gate drive signal Vgcl changes from the high-level power supply voltage VDD to the low-level power supply voltage VSS. Each exposure period Pex(1), ..., Pex(M) ends during the readout period Pdet when the gate drive signal Vgcl changes from the power supply voltage VSS to the power supply voltage VDD. The exposure times for each exposure period Pex(1), ..., Pex(M) are equal.

[0132] During the exposure period Pex{(1)···(M)}, a current flows in each partial detection region PAA in response to the light irradiated onto the photosensor PD. As a result, charge accumulates in each capacitive element Ca.

[0133] Before the start of the readout period Pdet, the control circuit 122 lowers the reset signal RST2 to a low voltage. This stops the operation of the reset circuit 17. Note that the reset signal may be at a high voltage only during the reset period Pst. During the readout period Pdet, similar to the reset period Pst, the gate line drive circuit 15 sequentially supplies the gate drive signals Vgcl(1), ..., Vgcl(M) to the gate line GCL.

[0134] Specifically, as shown in Figure 21, the gate line drive circuit 15 supplies a gate drive signal Vgcl(1) with a high-level voltage (power supply voltage VDD) to the gate line GCL(1) during the row readout period VR(1). The control circuit 122 sequentially supplies selection signals ASW1, ..., ASW6 to the signal line selection circuit 16 during the period when the gate drive signal Vgcl(1) is at a high-level voltage (power supply voltage VDD). As a result, the signal lines SGL of the partial detection region PAA selected by the gate drive signal Vgcl(1) are connected to the detection circuit 48 sequentially or simultaneously. Consequently, a detection signal Vdet is supplied to the detection circuit 48 for each partial detection region PAA.

[0135] Similarly, the gate line drive circuit 15 supplies high-level voltage gate drive signals Vgcl(2), ..., Vgcl(M-1), and Vgcl(M) to the gate lines GCL(2), ..., GCL(M-1), and GCL(M) respectively during row readout periods VR(2), ..., VR(M-1), and VR(M). That is, the gate line drive circuit 15 supplies the gate drive signal Vgcl to the gate line GCL for each row readout period VR(1), VR(2), ..., VR(M-1), and VR(M). For each period during which each gate drive signal Vgcl is at a high voltage, the signal line selection circuit 16 sequentially selects the signal line SGL based on the selection signal ASW. The signal line selection circuit 16 sequentially connects each signal line SGL to one detection circuit 48. As a result, during the readout period Pdet, the detection device 1 can output the detection signal Vdet for all partial detection areas PAA to the detection circuit 48.

[0136] The following describes an example of operation during the row readout period VR, which is the supply period of one gate drive signal Vgcl(j) in Figure 19, with reference to Figure 22. In Figure 19, the sign of the row readout period VR is attached to the first gate drive signal Vgcl(1), and the same applies to the other gate drive signals Vgcl(2), ..., Vgcl(M). j is a natural number from 1 to M.

[0137] As shown in Figures 22 and 17, the output (Vout) of the third switching element TrS is reset to a reference potential (Vref) voltage. The reference potential (Vref) voltage is the reset voltage, for example, 0.75V. Next, the gate drive signal Vgcl(j) goes high, turning on the first switching element Tr for that row, and the signal line SGL for each row becomes a voltage corresponding to the charge stored in the capacitance (capacitance element Ca) of the partial detection region PAA. After a period t1 has elapsed from the rising edge of the gate drive signal Vgcl(j), a period t2 occurs in which the selection signal ASW(k) goes high. When the selection signal ASW(k) goes high and the third switching element TrS turns on, the output (Vout) of the third switching element TrS (see Figure 17) changes to a voltage corresponding to the charge stored in the capacitance (capacitance element Ca) of the partial detection region PAA, which is connected to the detection circuit 48 via the third switching element TrS (period t3). In the example in Figure 22, this voltage drops from the reset voltage, as shown in period t3. Subsequently, when the switch SSW is turned on (period t4, when the SSW signal is high), the charge accumulated in the capacitance (capacitance element Ca) of the partial detection region PAA moves to the capacitance (capacitance element Cb) of the detection signal amplification circuit 42 of the detection circuit 48, and the output voltage of the detection signal amplification circuit 42 becomes a voltage corresponding to the charge accumulated in the capacitance element Cb. At this time, the inverting input of the detection signal amplification circuit 42 becomes an imaginary short-circuit potential of the operational amplifier, and returns to the reference potential (Vref). The output voltage of the detection signal amplification circuit 42 is read out by the A / D conversion circuit 43. In the example in Figure 22, the waveforms of the selection signals ASW(k), ASW(k+1), ... corresponding to the signal lines SGL of each column become high, sequentially turning on the third switching element TrS, and by sequentially performing the same operation, the charge accumulated in the capacitance (capacitance element Ca) of the partial detection region PAA connected to the gate line GCL is sequentially read out. Note that ASW(k), ASW(k+1)... in Figure 22 are, for example, any of ASW1 through ASW6 in Figure 22.

[0138] Specifically, when the switch SSW is ON for a period t4, charge moves from the capacitance of the partial detection region PAA (capacitance element Ca) to the capacitance of the detection signal amplification circuit 42 (capacitance element Cb) of the detection circuit 48. At this time, the non-inverting input (+) of the detection signal amplification circuit 42 is biased to a reference potential (Vref) voltage (for example, 0.75[V]). Therefore, due to an imaginary short circuit between the inputs of the detection signal amplification circuit 42, the output (Vout) of the third switching element TrS also becomes the reference potential (Vref) voltage. In addition, the voltage of the capacitance element Cb becomes a voltage corresponding to the charge accumulated in the capacitance of the partial detection region PAA (capacitance element Ca) at the point where the third switching element TrS was turned ON according to the selection signal ASW(k). The output of the detection signal amplification circuit 42 becomes a voltage corresponding to the capacitance of the capacitance element Cb after the output (Vout) of the third switching element TrS becomes the reference potential (Vref) voltage due to the imaginary short circuit, and this output voltage is read by the A / D conversion circuit 43. The voltage of the capacitive element Cb is, for example, the voltage between the two electrodes provided in the capacitor that constitutes the capacitive element Cb.

[0139] For example, period t1 is 20 [μs]. Period t2 is 60 [μs]. Period t3 is 44.7 [μs]. Period t4 is 0.98 [μs].

[0140] Figure 23 is an explanatory diagram illustrating the relationship between the driving of the sensor area and the lighting operation of the light source in the comparative example. Figure 23 shows the case in which the first light source 61 and the second light source 62 are lit alternately, i.e., lit in a time-division manner, similar to the comparative example described above (Figure 2). In the example shown in Figure 23, a reset period Pst, an exposure period Pex, and a readout period Pdet are provided for the detection of one frame in each of the periods t(1), t(2), t(3), and t(4). During the reset period Pst and the readout period Pdet, the gate line driving circuit 15 sequentially scans from gate line GCL(1) to gate line GCL(M).

[0141] As shown in Figure 23, in each of the periods t(1), t(2), t(3), and t(4), the detection device 1 performs the reset period Pst, exposure period Pex{(1)···(M)}, and readout period Pdet as described above. During the reset period Pst and readout period Pdet, the gate line drive circuit 15 sequentially scans from gate line GCL(1) to gate line GCL(M). In the following description, detection in each period t, i.e., detection in which the gate line GCL(1) is scanned from gate line GCL(M) to gate line GCL(M) during the reset period Pst and readout period Pdet, and the detection signal Vdet is obtained from the signal line SGL of each column, is referred to as detection for one frame. An example is shown in which the first light source 61 is lit during periods t(1) and t(3), and the second light source 62 is lit during periods t(2) and t(4). In other words, in the example shown in Figure 23, the control circuit 122 alternately switches the first light source 61 and the second light source 62 on and off each time a frame is detected.

[0142] As shown in Figure 23, when detecting one frame in period t(1), the control circuit 122 (detection control unit 11) turns on the first light source 61 and turns off the second light source 62 during the exposure period Pex. Similarly, when detecting one frame in period t(2), the control circuit 122 (detection control unit 11) turns off the first light source 61 and turns on the second light source 62 during the exposure period Pex. Likewise, when detecting one frame in period t(3), the first light source 61 is turned on and the second light source 62 is turned off during the exposure period Pex, and when detecting one frame in period t(4), the first light source 61 is turned off and the second light source 62 is turned on during the exposure period Pex.

[0143] As shown in the comparative example in Figure 23, the first light source 61 and the second light source 62 are controlled to light up or not light up in a time-division manner for each frame detected. As a result, the first detection signal detected by the photosensor PD using the first light and the second detection signal detected by the photosensor PD using the second light are output to the detection circuit 48 in a time-division manner.

[0144] Figure 24 is an explanatory diagram illustrating the relationship between the driving of the sensor area of ​​the detection device of the present disclosure and the lighting operation of the light source. In contrast to the above comparative example in which the first light source 61 and the second light source 62 are lit in a time-division manner, in the present disclosure the first light source 61 and the second light source 62 are lit simultaneously. As shown in Figure 24, the control circuit 122 lights up the first light source 61 and the second light source 62 simultaneously in period t(1). Similarly, the first light source 61 and the second light source 62 are lit simultaneously in periods t(2), t(3), and t(4). The control circuit 122 executes an exposure period Pex and a readout period Pdet in each period. Therefore, the frame rate can be increased compared to the case of Figure 23 in which the lights are lit in a time-division manner.

[0145] Figures 19 to 23 show an example in which the gate line drive circuit 15 individually selects gate lines GCL, but the circuit is not limited to this. The gate line drive circuit 15 may simultaneously select two or more predetermined gate lines GCL and sequentially supply a gate drive signal Vgcl for each predetermined number of gate lines GCL. The signal line selection circuit 16 may also simultaneously connect two or more predetermined signal lines SGL to a single detection circuit 48. Furthermore, the gate line drive circuit 15 may scan by thinning out multiple gate lines GCL.

[0146] As shown in Figure 21, during the row readout period VR(1), the selection signals ASW1, ..., ASW6 are sequentially supplied to the signal line selection circuit 16 during the period when the gate drive signal Vgcl(1) is at a high voltage level (power supply voltage VDD). That is, even after the selection signal ASW1 becomes a low voltage level at time t11, exposure continues during the exposure period Pex-1 until the gate drive signal Vgcl(1) becomes a low voltage level at time t13. A charge corresponding to the exposure period Pex-1 is charged from the photosensor PD to the signal line SGL(1) corresponding to the selection signal ASW1.

[0147] Similarly, charge is accumulated on each signal line SGL during exposure periods Pex-1, ..., Pex-6 corresponding to each selection signal ASW1, ..., ASW6. For example, exposure period Pex-6 is the period from when the selection signal ASW6 becomes a low voltage at time t12 until when the gate drive signal Vgcl(1) becomes a low voltage at time t13, and the exposure period Pex differs for each column.

[0148] Then, in the next row readout period VR(2), the detection signal Vdet for the second row is supplied to the detection circuit 48, and the signal is the sum of the charge accumulated during the exposure period Pex-1(SGL(1))····Pex-6(SGL(6)) of the previous row readout period VR(1).

[0149] As described above, the detection device 1 can be configured to include, for example, multiple light sources (first light source 61, second light source 62) with different wavelengths of emitted light, thereby enabling the acquisition of fingerprints obtained by detecting light reflected from the surface of the subject's fingers, and various other biometric information obtained by detecting light reflected or transmitted from inside the subject's fingers, wrists, etc.

[0150] The following describes an example of acquiring pulse waves, which are biological information used to calculate blood oxygen saturation (hereinafter referred to as blood oxygen saturation (SpO2)), as a specific example of biological information acquired by the detection device 1. Figure 25 is a schematic plan view showing the relationship between the sensor area of ​​the detection device according to the embodiment and the first and second light sources.

[0151] As shown in Figure 25, the detection device 1 has a filter 63. The filter 63 is positioned to overlap the detection area AA from one end to the other of the sensor area 10 in the scanning direction SCAN. The filter 63 has a transmission band that transmits the first light emitted from the first light source 61 and the second light emitted from the second light source 62. In the configuration according to this embodiment, the filter 63 is not necessarily required, and a configuration without the filter 63 is also possible.

[0152] In the configuration shown in Figure 25, the scanning direction SCAN is the direction in which the gate line drive circuit 15 scans the gate line GCL. That is, one gate line GCL extends in the first direction Dx in the detection region AA and is connected to multiple partial detection regions PAA provided in the detection region AA. In addition, one signal line SGL extends in the second direction Dy in the detection region AA and is connected to multiple optical sensors PD in the detection region AA.

[0153] The first light source substrate 51 and the second light source substrate 52 are facing each other in the first direction Dx, with the detection region AA in between, in a plan view. Multiple first light sources 61 are provided on the surface of the first light source substrate 51 that faces the second light source substrate 52. Similarly, multiple second light sources 62 are provided on the surface of the second light source substrate 52 that faces the first light source substrate 51. The multiple first light sources 61 and the multiple second light sources 62 are arranged in the first direction Dx along the outer circumference of the detection region AA.

[0154] The first light source 61 emits first light in a direction parallel to the first direction Dx. As a result, the detection area AA is illuminated with first light. The second light source 62 emits second light in a direction parallel to the first direction Dx. As a result, the detection area AA is illuminated with second light.

[0155] Figure 26A is a side view of the detection device shown in Figure 25, viewed from the first direction Dx. Figure 26A is a view of the detection device from the side of the first light source substrate 51 in Figure 13. Figure 26B is a side view of the detection device shown in Figure 25, viewed from the opposite side of the first direction Dx. Figure 26B is a view of the detection device from the side of the second light source substrate 52 in Figure 13. As shown in Figures 26A and 26B, the object to be detected, such as the subject's finger Fg or wrist, is in contact with or close to the sensor area 10 via the filter 63. The first light source 61 and the second light source 62 are positioned above the sensor area 10 and the filter 63, and are positioned on either side of the object to be detected, such as the subject's finger Fg or wrist, in the first direction Dx.

[0156] Here, for example, the first light emitted from the first light source 61 is green visible light (green light) with a wavelength of 490 nm to 550 nm, and the second light emitted from the second light source 62 is red visible light (red light) with a wavelength of 640 nm to 770 nm. When obtaining human blood oxygen saturation (SpO2), the pulse wave obtained by the first light (green light) and the pulse wave obtained by the second light (red light) are used. Note that the combination of the first and second lights is not limited to green light and red light, but any combination that can calculate SpO2 is acceptable. For example, infrared light and red light may also be used. In this case, the first and second lights must be combinations with different reflectance ratios of oxyhemoglobin and deoxygenated hemoglobin.

[0157] Since the amount of light absorbed changes depending on the amount of oxygen taken in by hemoglobin, the amount of light absorbed by the blood (hemoglobin) is detected by the photosensor PD from the amount of first and second irradiated light. Most of the oxygen in the blood is reversibly bound to hemoglobin in red blood cells, and a small amount is dissolved in the plasma. More specifically, oxygen saturation is the value of what percentage of the blood's capacity oxygen is bound to the blood as a whole. With two wavelengths of light, first and second, it is possible to calculate blood oxygen saturation from the amount of light absorbed by the blood (hemoglobin) from the amount of irradiated light.

[0158] Oxygen saturation (SpO2) is determined by the ratio of hemoglobin in the blood that is bound to oxygen (O2Hb: oxygenated hemoglobin) to hemoglobin that is not bound to oxygen (HHb: reduced hemoglobin). The absorption characteristics of red light are HHb >> O2Hb, with HHb having a significantly higher absorbance, whereas, for example, the absorption characteristics of infrared light are HHb ≈ O2Hb, with O2Hb having a slightly higher absorbance.

[0159] The first light emitted from the first light source 61 travels in a direction parallel to the first direction Dx and enters the subject's finger Fg or wrist. The first light emitted from the first light source 61 penetrates into the body and is reflected inside the subject's finger Fg or wrist. The reflected light reflected inside the subject's finger Fg or wrist travels in the third direction Dz, passes through the filter 63 and enters the detection area AA of the sensor area 10.

[0160] The second light emitted from the second light source 62 travels in a direction parallel to the first direction Dx and enters the subject's finger Fg or wrist. The second light emitted from the second light source 62 penetrates into the body and is reflected inside the subject's finger Fg or wrist. The reflected light reflected inside the subject's finger Fg or wrist travels in the third direction Dz, passes through the filter 63, and enters the detection area AA of the sensor area 10.

[0161] The arrangement of the multiple first light sources 61 and the multiple second light sources 62 is not limited to the examples shown in Figures 25, 26A, and 26B. For example, the first or second light may be irradiated from above the detected object, such as the subject's finger Fg or wrist, as shown in Figure 26A, specifically from the third direction Dz. Alternatively, the multiple first light sources 61 and the multiple second light sources 62 may be so-called direct-below type light sources, for example, located directly below the detection area AA. [Explanation of symbols]

[0162] 1. Detection device 10 Sensor area 11 Detection control circuit 40 Detection Circuit 44 Signal Processing Circuits 46 Memory circuit 48 Detection Circuit 61G green light source 61R red light source 61 1st light source 62 Second light source 122 Control circuits AA detection area PAA1, PAA2 Optical Sensors

Claims

1. A first light sensor that detects light, A second light sensor is provided adjacent to the first light sensor and detects light, A first light source that emits light of a predetermined wavelength, A second light source that emits light with a different wavelength from the wavelength of light emitted by the first light source, A control unit that causes the first light source and the second light source to emit light simultaneously, A signal processing unit that performs a process to acquire blood oxygen saturation based on the value detected by the first optical sensor and the value detected by the second optical sensor, Includes, The first light source, the first light sensor, the second light sensor, and the second light source are arranged in that order. When the first light source is lit, the second light source is not lit, and when the second light source is lit, the first light source is not lit. When the first light source is lit and the second light source is not lit, the first light sensor is used, and the second light sensor is not used. The first light sensor is used even when the second light source is lit and the first light source is not lit, and the second light sensor is not used. When both the first light source and the second light source are lit, both the first light sensor and the second light sensor are used. The first and second light sensors detect light that is reflected inside or transmitted through a living organism. Detection device.

2. The first light sensor is positioned between the second light sensor and the first light source, The second light sensor is positioned between the first light sensor and the second light source. The detection device according to claim 1.

3. The second light sensor is positioned between the first light sensor and the first light source, The second light sensor is positioned between the first light sensor and the second light source. The detection device according to claim 1.

4. The AC component of the value detected by the first light sensor is AC(Pix1), The DC component of the value detected by the first light sensor is DC(Pix1), The AC component of the value detected by the second optical sensor is AC(Pix2), The DC component of the value detected by the second light sensor is DC(Pix2), In that case, The detection device according to any one of claims 1 to 3, wherein the signal processing unit calculates blood oxygen saturation SpO2 by the following formula. SpO2=b'-a'・R' However, a' and b' are predetermined coefficients. R'={AC(Pix1) / DC(Pix1)} / {AC(Pix2) / DC(Pix2)} That is the case.

5. The system further includes a third light sensor provided adjacent to the second light sensor for detecting light, The third light sensor detects light that is reflected inside or transmitted through the living body, The signal processing unit, Using the detection values ​​from any two of the first, second, and third optical sensors, the blood oxygen saturation SpO2 is calculated, Calculate the average value of the calculated blood oxygen saturation (SpO2). A detection device according to any one of claims 1 to 3.

6. A third light sensor is provided adjacent to the second light sensor and detects light, A fourth light sensor is provided adjacent to the third light sensor to detect light, It further includes, The third and fourth light sensors detect light that is reflected inside or transmitted through the living body. The signal processing unit, Based on the values ​​detected by the first and third optical sensors, the first blood oxygen saturation (SpO2) is calculated; based on the values ​​detected by the first and fourth optical sensors, the second blood oxygen saturation (SpO2) is calculated; based on the values ​​detected by the second and third optical sensors, the third blood oxygen saturation (SpO2) is calculated; based on the values ​​detected by the first and fourth optical sensors, the fourth blood oxygen saturation (SpO2) is calculated; and further, The average value of the first blood oxygen saturation SpO2, the second blood oxygen saturation SpO2, the third blood oxygen saturation SpO2, and the fourth blood oxygen saturation SpO2 is calculated. A detection device according to any one of claims 1 to 3.

7. When using four optical sensors, the signal processing unit measures four blood oxygen saturation levels (SpO2). １ , SpO2 ２ , SpO2 ３ and SpO2 ４ Calculate using the following formula: SpO2 １ =b １ -a １・ R １ 、R １ ={AC(Pix1) / DC(Pix1)} / {AC(Pix3) / DC(Pix3)}、 SpO2 ２ =b ２ -a ２・ R ２ 、R ２ ={AC(Pix1) / DC(Pix1)} / {AC(Pix4) / DC(Pix4)}、 SpO2 ３ =b ３ -a ３・ R ３ 、R ３ ={AC(Pix2) / DC(Pix2)} / {AC(Pix3) / DC(Pix3)}、 SpO2 ４ =b ４ -a ４・ R ４ 、R ４ ={AC(Pix2) / DC(Pix2)} / {AC(Pix4) / DC(Pix4)}、 Furthermore, the detection device according to claim 5, which calculates the average value SpO2 of four blood oxygen saturation levels by the following formula. SpO2=(SpO2 １ +S.I. ２ +S.I. ３ +S.I. ４ ) / 4

8. The detection device according to any one of claims 1 to 3, wherein the first light sensor and the second light sensor are organic photodiodes.

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