JP6757183B2 - Receiver and portable electronics - Google Patents

Description

The present invention relates to a receiver and a portable electronic device.

In recent years, due to the miniaturization of cameras, proximity sensors, orientation sensors, acceleration sensors, angular velocity sensors, illuminance sensors, and the like, the above-mentioned various sensors have been mounted on portable electronic devices such as smartphones. In particular, in an electronic device having a liquid crystal panel, the ambient brightness can be measured by an illuminance sensor, and the brightness of the backlight can be appropriately adjusted according to the ambient brightness. In order to realize illuminance measurement with spectral sensitivity characteristics close to luminosity factor, a technique is known in which a plurality of photodiodes having different spectral sensitivity characteristics are provided in an illuminance sensor and the photocurrent of each photodiode is calculated.

In addition, wristwatch-type terminals and glasses-type portable electronic devices have also been put into practical use as sub-terminals for smartphones, and an environment is in place that can constantly monitor and manage biological information such as the heart rate and amount of exercise of the carrier. .. In addition, these portable electronic devices used outdoors are equipped with an ultraviolet sensor to measure the intensity of ultraviolet rays contained in sunlight to promote the prevention of sunburn and record the accumulated amount of ultraviolet rays received during the day. Can be done. This makes it possible to manage the health information of the user using a portable electronic device.

For example, Patent Document 1 discloses an ultraviolet ray measuring device including a UV sensor and an illuminance sensor, each of which is provided with a light receiver, a voltage detection circuit, and an optical sensor window. In a portable electronic device equipped with an illuminance sensor and an ultraviolet sensor, an attempt has been made to make the sensor window of the ultraviolet sensor and the sensor window of the illuminance sensor common in order to reduce the number of optical sensor windows as much as possible and improve the design. There is.

Patent Document 2 discloses an optical sensor in which a visible light sensor and an ultraviolet sensor are integrated using an SOI substrate. Generally, in order to detect ultraviolet rays, photodiodes using compound semiconductors such as GaN-based and ZnO-based and SOI substrates have been used, but when these are used, the same chip as the signal processing IC is used. It is difficult to integrate on the above and the cost is high.

Patent Document 3 includes two light receiving elements having a structure in which a plurality of junction photodiodes having different spectral sensitivity characteristics are arranged in the vertical direction, and a UV (ultraviolet) cut filter provided on one light receiving element. A light receiver that measures the intensity and illuminance of ultraviolet rays by taking the difference between the signal intensities of the two light receiving elements is disclosed.

By adopting such a difference method, it is possible to realize an ultraviolet receiver at low cost. To receive ultraviolet light, use the outermost PN junction photodiode that is sensitive to the ultraviolet region. Since visible light and infrared light pass through the UV cut filter, it is possible to measure the illuminance by using a PN junction photodiode at a deep position that is sensitive to the visible light region or the infrared region.

Further, since the above difference method can use a general-purpose silicon substrate, the cost can be reduced by integrating it on the same chip as the sensor circuit formed by the silicon CMOS (complementary metal oxide semiconductor) process. Can be planned. Furthermore, since both the ultraviolet rays and the illuminance can be detected by the light receiving element having the structure in which the plurality of junction photodiodes are arranged in the vertical direction, the ultraviolet sensor of the portable electronic device such as a smartphone and the optical sensor window of the illuminance sensor are shared. it can.

JP-A-2010-112714 Japanese Patent No. 5189391 International Publication No. 2015/151651

In the above-mentioned receiver, when light is obliquely incident on the light receiving element, the amount of light incident on the light receiving element is reduced by cos θ times as compared with the case where the light is incident from the front of the light receiving element. Further, as the amount of incident light on the light receiving element decreases, the characteristics of the cutoff frequency of the UV cut filter change and shift to the short wavelength side, so that the amount of incident light on the light receiving element further decreases. In order to avoid such a decrease in the amount of light incident on the light receiving element, the inclination of the light incident on the light receiving element is detected, and only the photocurrent obtained from the light incident on the front of the light receiving element is used for detecting ultraviolet rays and the like. It is conceivable to use it.

However, since the above-mentioned receiver cannot detect the inclination of the light incident on the light receiving element, it is difficult to use only the photocurrent obtained from the light incident from the front of the light receiving element for detecting ultraviolet rays and the like.

Therefore, an object of the present invention is to provide a light receiver capable of detecting the inclination of light incident on a light receiving element, and a portable electronic device provided with the light receiver.

In order to solve the above problems, the receiver of the present invention
A light receiving part having a light receiving region and
An optical filter that covers at least a part of the light receiving region and transmits light having a predetermined wavelength region.
A light-shielding portion that covers the light-receiving area and the optical filter,
With
The light receiving region is composed of a first light receiving region and a second light receiving region arranged around the first light receiving region, and light is incident on each of the first light receiving region and the second light receiving region. A light receiving element that allows photocurrent to flow is provided.
The optical filter transmits a part of light in a wavelength region in which the light receiving element has sensitivity.
The light-shielding portion has an opening for incident light into the first and second light-receiving regions, and the opening is viewed along the incident direction of the light incident on the first and second light-receiving regions. It is arranged so as to have an area of more than half of the first light receiving region in a plan view.
It is characterized by further including a tilt detecting unit that detects the tilt of the light incident on the light receiving region based on the intensity of the light incident on the first and second light receiving regions through the opening.

According to the light receiver of the present invention, the inclination of the light incident on the first and second light receiving regions can be detected based on the intensity of the light incident on the first and second light receiving regions of the light receiving unit.

The block diagram of the receiver of the 1st Embodiment of this invention. The perspective view of the light receiving part of the light receiver of FIG. FIG. 3 is a cross-sectional view of a light receiving portion of the receiver of FIG. The top view of the light receiving part of the light receiver of FIG. The block diagram which shows the structure of the A / D converter of the receiver of FIG. The timing chart which shows an example of the operation of the A / D converter of the receiver of FIG. The block diagram of the receiver of the 2nd Embodiment of this invention. FIG. 7 is a cross-sectional view of a state in which the photodiode PD_vis and the photodiode PD_ir of the light receiving element of the receiver of FIG. 7 are used. FIG. 7 is a cross-sectional view of a state in which the photodiode PD_ir of the light receiving element of the light receiving device of FIG. FIG. 7 is a cross-sectional view of a light receiving element of the light receiver of FIG. The figure which shows the spectral sensitivity characteristic of each photodiode of the light receiving element of the light receiver of FIG. FIG. 7 is a cross-sectional view showing an open / closed state of a switch when taking out a photocurrent of a photodiode PD_uv of a light receiving element of the light receiving device of FIG. 7. FIG. 5 is a cross-sectional view showing an open / closed state of a switch when taking out photocurrents of the photodiode PD_vis and the photodiode PD_ir of the light receiving element of the light receiver of FIG. 7. FIG. 7 is a cross-sectional view showing an open / closed state of a switch when the photocurrent of the photodiode PD_ir of the light receiving element of the light receiving device of FIG. 7 is taken out. The top view of the light receiving part of the light receiver of FIG. The figure which shows the spectral sensitivity characteristic of the photodiode PD_uv of the light receiving element of the light receiver of FIG. The figure which shows the spectral transmittance characteristic of the optical filter of the receiver of FIG. FIG. 7 is a diagram showing the spectral sensitivity characteristics of the photodiode PD_uv with respect to the light transmitted through the optical filter of the light receiving element of the light receiving device of FIG. 7. The figure which shows the spectral sensitivity characteristic of the whole light receiving part of the light receiver of FIG. Top view of another example of the light receiving portion of the light receiver of FIG. 7. The figure which shows the spectral sensitivity characteristic of the photodiode PD_uv with respect to the light which passed through the optical filter of FIG. 17 of the receiver of FIG. The figure which shows the spectral sensitivity characteristic of the whole light receiving part of the light receiver of FIG. The top view of the light receiving part of the light receiver of the 3rd Embodiment of this invention. The top view of the light receiving part of the light receiver of the 4th Embodiment of this invention. The top view of the light receiving part of the light receiver of the 5th Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, terms indicating a specific direction or position (for example, terms including "top", "bottom", "right", and "left") are used as necessary, but the use of these terms is used. Is for facilitating the understanding of the invention with reference to the drawings, and the meaning of those terms does not limit the technical scope of the present invention. In addition, the following description is merely an example and is not intended to limit the present invention, its application, or its use. Furthermore, the drawings are schematic, and the ratio of each dimension and the like do not always match the actual ones.

(First Embodiment)
As shown in FIG. 1, the light receiver 1 of the first embodiment of the present invention includes a light receiving unit 10 and a sensor circuit unit 20 connected to the light receiving unit 10. The receiver 1 of the first embodiment is used as, for example, an illuminance sensor.

As shown in FIG. 1, the light receiving unit 10 has light receiving regions 13 and 14, and as shown in FIG. 3, an optical filter 11 is provided on the light receiving regions 13 and 14. Further, the light receiving portion 10 is arranged inside the hollow housing 15.

As shown in FIG. 4, the light receiving regions 13 and 14 of the light receiving unit 10 are composed of a first light receiving region 13 having a square shape when viewed from above and a second light receiving region 14 arranged around the first light receiving region 13. Has been done. The first light receiving element PD1 is provided in the first light receiving region 13, and the second light receiving element PD2 is provided in the second light receiving region 14. The first light receiving element PD1 causes a photocurrent Iin1 to flow according to the intensity of the incident light, and the second light receiving element PD2 causes a light current Iin2 to flow according to the intensity of the incident light.

As shown in FIG. 3, the first and second light receiving elements PD1 and PD2 have the same cross-sectional structure as each other. That is, each of the first and second light receiving elements PD1 and PD2 is a P-type substrate P_sub, an N-type well layer N_well provided on the P-type substrate P_sub, and a P-type provided on the N-type well layer N_well. It has a diffusion layer P +.

Further, the first and second light receiving elements PD1 and PD2 include two photodiodes PD_vis and a photodiode PD_ir made of a PN junction. In the first light receiving element PD1, the P-type diffusion layer P + and the P-type substrate P_Sub are grounded (GND), and in the second light receiving element PD2, the P-type substrate P_Sub is grounded, and the P-type diffusion layer P + and The N-type well layer N_well is connected to each other.

The optical filter 11 is, for example, a luminosity factor correction filter, and is provided so as to cover the entire first and second light receiving regions 13 and 14, as shown in FIG.

Further, as shown in FIG. 3, shielding portions 12 are provided on the upper surfaces of the first and second light receiving elements PD1 and PD2 so that the P-type diffusion layer P + is exposed, respectively. As a result, light from the outside is incident on the P-type diffusion layer P +.

The housing 15 has a light-shielding portion 16 on a surface facing the light-receiving regions 13 and 14. The light-shielding portion 16 is provided with an opening 17 for allowing light to enter the light-receiving regions 13 and 14.

The opening 17 has a square shape that is one size smaller than the first light receiving region 13 in the top view, and the center thereof is arranged so as to coincide with the center of the first light receiving region 13.

As shown in FIG. 1, the sensor circuit unit 20 includes A / D converters ADC1 and ADC2, a tilt detection unit 21, and an incident state determination unit 22.

The A / D converter ADC1 is connected to the first light receiving element PD1 and changes the photocurrent Iin1 into a digital signal to output the digital output value ADCOUNT1. The digital output value ADCOUNT1 corresponds to the intensity of the light incident on the first light receiving element PD1.

The A / D converter ADC2 is connected to the second light receiving element PD2, changes the photocurrent Iin2 into a digital signal, and outputs a digital output value ADCOUNT2. The digital output value ADCOUNT2 corresponds to the intensity of the light incident on the second light receiving element PD2.

Further, the A / D converters ADC1 and ADC2 have the same configuration, and as shown in FIG. 5, the input terminal IN, the output terminal OUT, the charging circuit 23, the comparison circuit 24, and the control circuit 25 , And a discharge circuit 26.

The A / D converters ADC1 and ADC2 operate as shown in FIG. 6, for example. In FIG. 6, CLK indicates a clock signal, SW1 and SW2 indicate the open / closed state of switches SW1 and SW2 in FIG. 5, Vref indicates the voltage of the reference power supply V1 in FIG. 5, and COMP indicates the output of the comparison circuit 24. CHARGE indicates the output of the control circuit 25 used for opening and closing the switch SW2.

Since the switch SW1 is closed before the start of the conversion operation, the output VSIG of the charging circuit 23 (integrating circuit) is charged to the voltage Vref of the reference power supply V1.

When the switch SW1 is turned off, the A / D converters ADC1 and ADC2 can charge the capacitor C1 with the photocurrent Iin, and perform the AD conversion operation. The off period of the switch SW1 is the data conversion period (charging period, t_conv), which corresponds to the measurement time.

In the data conversion period (t_conv), first, the switch SW2 is turned on, and a constant charge (Iref × t_clk) is discharged from the capacitor C1 by the discharge circuit 26 (precharge period). After that, when the switch SW2 is switched from on to off, the charging circuit 23 is charged by the photocurrent Iin, and its output VSIG rises. When the output VSIG exceeds the voltage Vref, the output COMP of the comparison circuit 24 switches from low voltage to high voltage. As a result, the output of the control circuit 25 is switched from the low voltage to the high voltage, the switch SW2 is turned on, and a constant charge (IREF × I_ref) is discharged by the discharge circuit 26.

During the data conversion period (t_conv), the counter of the control circuit 25 counts the discharge time (the time when the output of the control circuit 25 changes from low voltage to high voltage), and this count value is the input charge amount. It is digitally output as a value according to. The output of the counter is the outputs ADCOUNT1 and ADCOUNT2 of the A / D converters ADC1 and ADC2.

Since the A / D converters ADC1 and ADC2 operate so that the amount of charge charged by the photocurrent Iin and the amount of discharged charge are equal to each other, "charge amount (Iin × t_conv) = discharge charge amount (IREF)". The following equation (1) holds by (× t_clk × count). Therefore, the minimum resolution of the count is determined by (IREF × t_clk). In the following equation (1), t_clk is the clock period and t_conv is the charge. The period, count indicates the value obtained by counting the discharge time, and IREF indicates the reference current value.
count = (Iin × t_conv) / (IREF × t_clk)… (1)

The tilt detection unit 21 detects the tilt of the incident light incident on the light receiving regions 13 and 14 based on the digital output values ADCOUNT1 and ADCOUNT2. For example, when the incident direction of the incident light incident on the first and second light receiving regions 13 and 14 is changed from L1 to L2 shown in FIG. 2, as shown in FIG. 4, the first and second light receiving regions 13 and 14 The range of incident light incident on is changed from L1 to L2. That is, the digital output value ADCOUNT2 increases as the inclination of the incident light incident on the light receiving regions 13 and 14 increases. Therefore, the slope of the incident light incident on the first and second light receiving regions 13 and 14 can be obtained by the following equation (2).
ADCOUNT2 / (ADCOUNT1 + ADCOUNT2) ... (2)

The incident state determination unit 22 determines whether or not the incident state of the light incident on the first and second light receiving regions 13 and 14 is normal based on the inclination of the incident light detected by the inclination detecting unit 21. .. Whether or not the incident state of light is normal is determined by whether or not the inclination of the incident light detected by the inclination detecting unit 21 is equal to or less than a predetermined threshold value. The predetermined threshold value can be arbitrarily set according to the size of the opening 17 of the light-shielding portion 16 or the intensity of the light incident on the first and second light receiving regions 13 and 14.

As described above, according to the receiver 1 of the first embodiment, the first and second light receiving regions 13 and 14 are based on the intensity of the light incident on the first and second light receiving regions 13 and 14 of the light receiving unit 10. The tilt detecting unit 21 for detecting the tilt of the light incident on the light is provided. Thereby, the inclination of the light incident on the first and second light receiving regions 13 and 14 can be detected.

At this time, the inclination of the light incident on the first and second light receiving regions 13 and 14 can be obtained by the above equation (2). That is, with a simple configuration, the inclination of the light incident on the first and second light receiving regions 13 and 14 can be detected.

Further, the incident state determining unit 22 for determining whether or not the incident state of the light incident on the first and second light receiving regions 13 and 14 is normal based on the inclination of the light detected by the inclination detecting unit 21 Further prepared. As a result, for example, among the lights incident on the first and second light receiving regions 13 and 14, only the light whose incident state is determined to be normal is used for the detection of the ultraviolet intensity, thereby improving the detection accuracy of the ultraviolet intensity. Can be enhanced.

The opening 17 of the light-shielding portion 16 is more than half of the first light-receiving area 13 in top view (planar view of the light incident on the first and second light-receiving areas 13 and 14 along the incident direction). It suffices to have an area, and its shape and size can be changed according to the design of the receiver 1. For example, the center of the opening 17 may not coincide with the center of the first light receiving region, or may have a shape different from that of the first light receiving region.

Further, it is preferable that the opening 17 has the same shape and size as the first light receiving region, and is arranged so that the center coincides with the center of the first light receiving region. As a result, it is possible to reduce the bias of the detection sensitivity depending on the direction in which the light is tilted.

(Second Embodiment)
As shown in FIG. 7, the receiver 101 of the second embodiment of the present invention is different from the receiver 1 of the first embodiment in the following points. The receiver 101 of the second embodiment is used as, for example, an ultraviolet sensor.
The third and fourth light receiving elements PD11 and PD12 are provided in the first light receiving region 13 of the light receiving unit 110, the fifth light receiving element PD13 is provided in the second region, and the optical filter 11 covers the entire third light receiving element PD11. The point where the UV cut filter is placed.
A point that the sensor circuit unit 120 is provided with A / D converters ADC1, ADC2, and ADC3 connected to each of the third to fifth light receiving elements PD11, PD12, and PD13.

The third to fifth light receiving elements PD11, PD12, and PD13 have the same cross-sectional structure as shown in FIGS. 8 and 9. That is, each of the third to fifth light receiving elements PD11, PD12, and OD13 was formed on the P-type substrate P_sub, the N-type well layer N_well formed on the P-type substrate P_sub, and the N-type well layer N_well. It includes a P-type well layer P_well and an N-type diffusion layer N formed on the P-type well layer P_well. Further, the P-type well layer, the N-type well layer, and the P-type substrate are grounded (GND).

Note that FIG. 8 shows a state in which the photodiode PD_vis and the photodiode PD_ir of the third to fifth light receiving elements PD11, PD12, PD13 are used, and FIG. 9 shows the state in which the third to fifth light receiving elements PD11, PD12, It shows the state of using the photodiode PD_ir of PD13.

The third to fifth light receiving elements PD11, PD12, and PD13 have three PN junctions, and include a photodiode PD_ir formed by a PN junction between a P-type substrate and an N-type well layer, and an N-type well layer. It includes a photodiode PD_vis formed by a PN junction with a P-type well layer and a photodiode PD_uv formed by a PN junction between a P-type well layer and an N-type diffusion layer.

Shielding portions 12 are provided on the upper surfaces of the third to fifth light receiving elements PD11, PD12, and PD13 so that the N-type diffusion layer N is exposed, respectively. As a result, light from the outside is incident on the N-type diffusion layer N.

Further, as shown in FIG. 10, the third to fifth light receiving elements PD11, PD12, and PD13 are provided with five switches SW1 to SW5. The switches SW1 to SW1 change the connection relationship of each layer of the third to fifth light receiving elements PD11, PD12, PD13 (the connection relationship between the anode and the cathode of each photodiode), thereby changing the connection relationship of the third to fifth light receiving elements PD11, This is a switch for changing the spectral sensitivity characteristics of PD12 and PD13. By controlling switches SW1 to SW5, the photocurrent of any photodiode can be taken out. Note that FIG. 10 shows only the third light receiving element PD11.

The third to fifth light receiving elements PD11, PD12, and PD13 have the spectral sensitivity characteristics shown in FIG.

FIG. 12 shows the open / closed state of the switches of the third to fifth light receiving elements PD11, PD12, and PD13 when the photocurrent of the photodiode PD_uv is taken out. The spectral sensitivity characteristics of the third to fifth light receiving elements PD11, PD12, and PD13 at this time are as shown by the curve shown by PD_uv in FIG.

FIG. 13 shows the open / closed state of the switches of the third to fifth light receiving elements PD11, PD12, and PD13 when the photocurrents of the photodiode PD_vis and the photodiode PD_ir are taken out. The spectral sensitivity characteristics of the third to fifth light receiving elements PD11, PD12, and PD13 at this time are as shown by the curves shown by PD_vis + PD_ir in FIG.

FIG. 14 shows the open / closed state of the switches of the third to fifth light receiving elements PD11, PD12, and PD13 when the photocurrent of the photodiode PD_ir is taken out. The spectral sensitivity characteristics of the third to fifth light receiving elements PD11, PD12, and PD13 at this time are as shown by the curve shown by PD_ir in FIG.

The optical filter 11 is a UV cut filter in which the transmittance of light in the ultraviolet wavelength region (wavelength 400 nm or less) is lower than the transmittance of light outside the ultraviolet wavelength region. As shown in FIG. 7, the optical filter 11 receives a third light receiver. It covers the entire element PD11. The optical filter 11 is preferably one that can block light in the ultraviolet wavelength region (transmit light other than the ultraviolet wavelength region).

The A / D converter ADC1 is connected to the third light receiving element PD11, changes the photocurrent Iin1 into a digital signal, and outputs a digital output value ADCOUNT1. The digital output value ADCOUNT1 corresponds to the intensity of the light incident on the third light receiving element PD11.

The A / D converter ADC2 is connected to the fourth light receiving element PD12, changes the photocurrent Iin2 into a digital signal, and outputs a digital output value ADCOUNT2. The digital output value ADCOUNT2 corresponds to the intensity of the light incident on the fourth light receiving element PD12.

The A / D converter ADC3 is connected to the fifth light receiving element PD13, changes the photocurrent Iin3 into a digital signal, and outputs a digital output value ADCOUNT3. The digital output value ADCOUNT3 corresponds to the intensity of the light incident on the fifth light receiving element PD13.

The A / D converters ADC1, ADC2, and ADC3 have the same configuration, and as shown in FIG. 5, the input terminal IN, the output terminal OUT, the charging circuit 23, the comparison circuit 24, and the control circuit 25 , And a discharge circuit 26.

Next, the principle of detecting the ultraviolet intensity in the receiver 101 of the second embodiment will be described.

In the receiver 1 of the second embodiment, the inclination of the light incident on the first and second light receiving regions 13 and 14 and the bias of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12 are obtained in advance. And detect the UV intensity. Here, a detection method using the photocurrents of the photodiode PD_vis and the photodiode PD_ir will be described.

As shown in FIG. 8, after changing the connection relationship of each layer so that the third to fifth light receiving elements PD11, PD12, PD13 can take out the photocurrents of the photodiode PD_vis and the photodiode PD_ir, the first first. The inclination of the light incident on the second light receiving regions 13 and 14 and the deviation of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12 are detected in advance.

As shown in FIG. 15, when the incident direction of the incident light incident on the first and second light receiving regions 13 and 14 is changed from L1 to L2, as shown in FIG. 4, the first and second light receiving regions 13 and The range of incident light incident on 14 changes from L1 to L2. That is, as the inclination of the incident light incident on the light receiving regions 13 and 14 increases, the amount of light incident on the third and fourth light receiving elements PD11 and PD12 decreases, and the amount of light incident on the fifth light receiving element PD13 decreases. Will increase.

Further, as shown in FIG. 11, when the photocurrents of the photodiode PD_vis and the photodiode PD_ir are taken out, the third to fifth light receiving elements PD11, PD12, and PD13 are sensitive to the blocking band (up to 400 nm) of the optical filter 11. Almost no.

Therefore, the slope of the light incident on the first and second light receiving regions 13 and 14 is obtained by the following equation (3). In the following equation (3), "ADCOUNT1_vis_ir, ADCOUNT2_vis_ir, ADCOUNT3_vis_ir" are digital outputs output from the A / D converters ADC1, ADC2, and ADC3 when the photocurrents of the photodiode PD_vis and the photodiode PD_ir are taken out, respectively. The value.
ADCOUNT3_vis_ir / (ADCOUNT1_vis_ir ＋ ADCOUNT2_vis_ir ＋ ADCOUNT3_vis_ir)… (3)

The incident state determination unit 22 determines whether or not the incident state of light is normal based on the inclination of the light incident on the first and second light receiving regions 13 and 14 obtained by the above equation (3). .. The digital output values ADCOUNT1 to 3 determined to be normal in the incident state of light are used as effective values for detecting the intensity of ultraviolet rays.

Further, the bias of the light irradiation of the third light receiving element PD11 is obtained by the following formula (4), and the bias of the light irradiation of the fourth light receiving element PD12 is obtained by the following formula (5).
2 × ADCOUNT1_vis_ir / (ADCOUNT1_vis_ir ＋ ADCOUNT2_vis_ir)… (4)
2 × ADCOUNT2_vis_ir / (ADCOUNT1_vis_ir ＋ ADCOUNT2_vis_ir)… (5)

Subsequently, the ultraviolet intensity is detected. First, a case where the light irradiation of the third and fourth light receiving elements PD11 and PD12 is not biased will be described.

At this time, the third and fourth light receiving elements PD11 and PD12 are in the open / closed state of the switch when the photocurrent of the photodiode PD_uv shown in FIG. 12 is taken out.

As shown in FIG. 16, the peak wavelength of the spectral sensitivity characteristic of the photodiode PD_uv is about 450 nm. The peak wavelength can be adjusted by adjusting the junction depth of the PN junction in the light receiving element.

Further, as shown in FIG. 17, the optical filter 11 has a low transmittance of light having a wavelength of 400 nm or less, and a transmittance of light having a wavelength of 400 nm or more is almost 100%.

Light transmitted through the optical filter 11 is incident on the third light receiving element PD11. Therefore, the spectral sensitivity characteristic of the third light receiving element PD11 is as shown in FIG. On the other hand, since the optical filter 11 is not provided on the upper part of the fourth light receiving element PD12, the spectral sensitivity characteristic of the fourth light receiving element PD12 is as shown in FIG.

In the sensor circuit unit 20 of the receiver 101, the tilt detection unit 21 calculates the difference between the digital output value ADCOUNT2 and the digital output value ADCOUNT1. Since this difference is obtained by subtracting the intensity of the light incident on the third light receiving element PD11 from the intensity of the light incident on the fourth light receiving element PD12, the spectral sensitivity characteristics of the entire light receiving unit 110 are shown in FIG. Can be regarded as a thing.

As a result, since the light receiving unit 110 has sensitivity only in the ultraviolet region having a wavelength of 400 nm or less, the ultraviolet intensity can be accurately detected.

Next, a case where the light irradiation of the third and fourth light receiving elements PD11 and PD12 is biased will be described.

Since sunlight, which is the main light source to be measured when detecting ultraviolet intensity, has a wide spectral characteristic, it is used for the third and fourth light receiving elements PD11 (PD_uv) and PD12 (PD_uv) when detecting ultraviolet intensity. The bias of the amount of light to be irradiated and the bias of the light irradiation of the third and fourth light receiving elements PD11 (PD_vis + PD_ir) and PD12 (PD_vis + PD_ir) detected in advance by the above equations (4) and (5) It can be said that there is a correlation.

That is, the digital output value ADCOUNT1_uv of the A / D converter ADC1 output when the ultraviolet intensity is detected, and the digital output value ADCOUNT2_uv from the A / D converter ADC2 are detected in advance in the third and fourth light receiving elements PD11, By correcting the bias of the light irradiation of PD12, the ultraviolet intensity can be detected accurately.

The digital output value ADCOUNT1_uv2 of the A / D converter ADC1 corrected by the bias of the light irradiation of the third and fourth light receiving elements PD11 and PD12 detected in advance is the digital output value of the A / D converter ADC2 according to the following equation (6). The output value ADCOUNT2_uv2 is obtained by the following equation (7). In equations (6) and (7), the digital output values ADCOUNT1_uv and ADCOUNT2_uv of the A / D converters ADC1 and ADC2 are multiplied by the reciprocal of the light irradiation bias of the third and fourth light receiving elements PD11 and PD12 detected in advance. There is.
ADCOUNT1_uv2 = ADCOUNT1_uv × (ADCOUNT1_vis_ir + ADCOUNT2_vis_ir) / 2 × ADCOUNT1_vis_ir… (6)
ADCOUNT2_uv2 = ADCOUNT2_uv × (ADCOUNT1_vis_ir + ADCOUNT2_vis_ir) / 2 × ADCOUNT2_vis_ir… (7)

By differentiating the digital output values ADCOUNT1_uv2 and ADCOUNT2_uv2 obtained by the above equations (5) and (6), the light receiving unit 110 has sensitivity only in the ultraviolet region having a wavelength of 400 nm or less, and accurately detects the ultraviolet intensity. be able to.

According to the light receiving device 101 of the second embodiment, the third and fourth light receiving elements PD11 and PD12 are provided in the first light receiving region 13, and the entire first light receiving element PD11 is covered with the optical filter 11. Thereby, for example, in detecting the ultraviolet intensity, in addition to the inclination of the light incident on the first and second light receiving regions 13 and 14, the bias of the light irradiation of the third and fourth light receiving elements PD11 and PD12 is taken into consideration. Therefore, the detection accuracy of the ultraviolet intensity can be improved.

When the bias of the light irradiation of the third and fourth light receiving elements PD11 and PD12 obtained by the above formulas (4) and (5) greatly deviates from 1 (either of the third and third light receiving elements PD11 and PD12). The accuracy of the correction cannot be guaranteed (when almost no light is applied). In this case, the correction is not possible, and the digital output values obtained by the above equations (6) and (7) are set as invalid values.

Further, for example, the photocurrent of the photodiode PD_ir can be used instead of the photocurrent of the photodiode PD_vis and the photodiode PD_ir. In this case, as shown in FIG. 9, the connection relationship of each layer is changed so that the third to fifth light receiving elements PD11, PD12, and PD13 can take out the photocurrent of the photodiode PD_ir. Then, the inclination of the light incident on the first and second light receiving regions 13 and 14 and the bias of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12 are detected in advance, and the first detected in advance. , The ultraviolet intensity is detected based on the inclination of the light incident on the second light receiving regions 13 and 14 and the deviation of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12.

In the receiver 101 of the second embodiment, the optical filter 11 is arranged so as to cover the entire third light receiving element PD 11, but is not limited to this. For example, as shown in FIG. 20, the optical filter 11 may be arranged so as to cover a part of the third photodiode PD11. The spectral sensitivity characteristic of the third light receiving element PD11 in this case is as shown in FIG. 21, and the spectral sensitivity characteristic of the entire light receiving unit 110 can be regarded as shown in FIG. 22.

(Third Embodiment)
In the receiver 101 of the second embodiment, the third and fourth light receiving elements PD11 and PD12 are provided in the first light receiving region 13 of the light receiving unit 110, but the present invention is not limited to this. For example, as shown in FIG. 23, two third and fourth light receiving elements PD11 and PD12 may be provided in the first light receiving region 13 of the light receiving unit 210.

In the receiver 201 of the third embodiment, in the top view, the shielding portion 12 is provided so as to connect the middle of the opposite sides of the first receiving region 13, and the third region is covered by the shielding portion 12. , Fourth light receiving elements PD11 and PD12 are provided. One of the third and fourth light receiving elements PD11 and PD12 is arranged so as not to be adjacent to the other, and the optical filter 11 covers the third light receiving element PD11.

By arranging the third and fourth light receiving elements PD11 and PD12 in this way, it is possible to reduce the bias of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12.

By increasing the number of divisions of the first light receiving region 13, the deviation of the light irradiation amount of the third and fourth light receiving elements PD11 and PD12 can be further reduced.

(Fourth Embodiment)
In the light receiver 1 of the first embodiment, the optical filter 11 is arranged so as to cover the entire first and second light receiving regions 13 and 14 of the light receiving unit 10, but the present invention is not limited to this. For example, as shown in FIG. 24, the optical filter 11 may be arranged so as to cover the entire first light receiving region 13 of the light receiving unit 310 and a part of the second light receiving region 14.

In the receiver 301 of the fourth embodiment, the optical filter 11 is arranged so that the portion of the first and second light receiving regions 13 and 14 excluding the outer peripheral edge portion of the second light receiving region 14 is covered in the top view. doing. Even in this case, the inclination of the light incident on the first and second light receiving regions 13 and 14 can be detected by the same method as that of the receiver 1 of the first embodiment.

(Fifth Embodiment)
In the receiver 101 of the second embodiment, the optical filter 11 is arranged so as to cover the entire third light receiving element PD 11 in the first light receiving region 13 of the light receiving unit 110, but the present invention is not limited to this. For example, as shown in FIG. 25, the light receiving unit 410 is arranged so as to cover a part of the third and fourth light receiving elements PD11 and PD12 of the first light receiving region 13 and a part of the second light receiving region 14. May be good.

The receiver 401 of the fifth embodiment includes five optical filters 11, one optical filter 11 in the first light receiving region 13 and four optical filters 11 in the second light receiving region 13. The optical filter 11 arranged in the first light receiving region 13 is arranged so as to cover a part of the third and fourth light receiving elements PD11 and PD12 in the top view. The optical filters 11 arranged in the second light receiving region 14 are arranged along the outer circumference of the second light receiving region 14 without overlapping each other. Even in this case, the inclination of the light incident on the first and second light receiving regions 13 and 14 can be detected by the same method as that of the receiver 101 of the second embodiment.

The receivers 1, 101, 201, 301, 401 of the first to fifth embodiments can be applied to, for example, a portable electronic device.

The present invention and embodiments can be summarized as follows.

The receivers 1,101,201,301,401 of the present invention are
Light receiving portions 10, 110, 210, 310, 410 having light receiving regions 13, 14 and
An optical filter 11 that covers at least a part of the light receiving regions 13 and 14 and transmits light having a predetermined wavelength region.
A light-shielding portion 16 that covers the light-receiving areas 13 and 14 and the optical filter 11 and
With
The light receiving regions 13 and 14 are composed of a first light receiving region 13 and a second light receiving region 14 arranged around the first light receiving region 13, and each of the first and second light receiving regions 13 and 14 is formed. Is provided with light receiving elements PD1, PD2, PD11, PD12, PD13 that allow light current to flow when light is incident on the surface.
The optical filter 11 transmits a part of light in a wavelength region in which the light receiving elements PD1, PD2, PD11, PD12, and PD13 have sensitivity.
The light-shielding portion 16 has an opening for incident light on the light-receiving areas 13 and 14, and the opening 17 is in the incident direction of the light incident on the first and second light-receiving areas 13 and 14. It is arranged so as to have an area of half or more of the first light receiving region 13 in a plan view viewed along the line.
Inclination detection that detects the inclination of the light incident on the first and second light receiving regions 13 and 14 based on the intensity of the light incident on the first and second light receiving regions 13 and 14 through the opening 17. It is characterized in that the portion 21 is further provided.

According to the above configuration, it is incident on the first and second light receiving regions 13 and 14 based on the intensity of the light incident on the first and second light receiving regions 13 and 14 of the light receiving portions 10, 110, 210, 310 and 410. The inclination of the light can be detected.

Further, in the receivers 1,101,201,301,401 of one embodiment,
Incident state determination unit 22 that determines whether or not the incident state of the light incident on the first and second light receiving regions 13 and 14 is normal based on the inclination of the light detected by the inclination detecting unit 21. Further prepare.

According to the above embodiment, for example, among the lights incident on the first and second light receiving regions 13 and 14, only the light whose incident state is determined to be normal is used for detecting the ultraviolet intensity. Detection accuracy can be improved.

Further, in the receivers 1,101,201,301,401 of one embodiment,
A plurality of light receiving elements PD11 and PD12 are provided in the first light receiving region 13, and a plurality of light receiving elements PD11 and PD12 are provided.
The optical filter 11 is configured so that the transmittance of light in a predetermined wavelength region is lower than the transmittance of light in this predetermined wavelength region.
One of the plurality of light receiving elements PD11 and PD12 is covered with the optical filter 11.

According to the above embodiment, for example, in detecting the intensity of ultraviolet rays, it is possible to consider the bias of light irradiation of the light receiving elements PD11 and PD12 in addition to the inclination of the light incident on the first and second light receiving regions 13 and 14. Therefore, the detection accuracy of the ultraviolet intensity can be improved.

The portable electronic device of the present invention includes the above-mentioned receiver.

According to the above configuration, a portable electronic device provided with a light receiver capable of detecting the inclination of light incident on the light receiving element can be obtained.

Of course, the components described in the first to fifth embodiments may be combined as appropriate, and may be appropriately selected, replaced, or deleted as appropriate.

1,101,201,301,401 Receiver 10,110,210,310,410 Light receiving part 11 Optical filter 12 Shielding part 13 First light receiving area 14 Second light receiving area 15 Housing 16 Shading part 17 Opening 20, 120 Sensor Circuit unit 21 Tilt detection unit 22 Incident state determination unit 23 Charging circuit 24 Comparison circuit 25 Control circuit 26 Discharge circuit PD1 First light receiving element PD2 Second light receiving element PD3 Third light receiving element PD4 Fourth light receiving element PD5 Fifth light receiving element

Claims (4)

A light receiving part having a light receiving region arranged on a flat surface ,
An optical filter that covers at least a part of the light receiving region and transmits light having a predetermined wavelength region.
A light-shielding portion that covers the light-receiving area and the optical filter,
With
The light receiving region is composed of a first light receiving region and a second light receiving region arranged around the first light receiving region, and light is incident on each of the first light receiving region and the second light receiving region. A light receiving element that allows photocurrent to flow is provided.
The optical filter transmits a part of light in a wavelength region in which the light receiving element has sensitivity.
The light-shielding portion has an opening for allowing light to enter the first and second light-receiving areas, and the opening is the first in a plan view in which the first and second light-receiving areas are arranged . It is arranged so as to have an area of more than half of the light receiving area.
A receiver further comprising a tilt detecting unit that detects the tilt of light incident on the light receiving region based on the intensity of light incident on the first and second light receiving regions through the opening. In the receiver according to claim 1,
An incident state determining unit for determining whether or not the incident state of the light incident on the first and second light receiving regions is normal based on the inclination of the light detected by the inclination detecting unit is further provided. A featured receiver. In the receiver according to claim 1 or 2,
A plurality of the light receiving elements are provided in the first light receiving region.
A receiver characterized in that one of the plurality of light receiving elements is covered with the optical filter. A portable electronic device provided with the receiver according to any one of claims 1 to 3.

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