CN111947689A - Method for eliminating ambient light and optical crosstalk of optical proximity sensing device - Google Patents
Method for eliminating ambient light and optical crosstalk of optical proximity sensing device Download PDFInfo
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Abstract
The invention provides a method for eliminating ambient light and optical crosstalk of an optical proximity sensing device, which mainly comprises a control and processing circuit, a light emitting unit, a light receiving unit, a digital-analog conversion module, an analog adder and a light-digital conversion module which form the optical proximity sensing device. Then, a noise elimination process is performed on an ambient light signal and/or an optical crosstalk signal by using the optical frequency conversion technique during a light emitting period and a turn-off period of the light emitting unit. Particularly, the invention uses the optical digital conversion module to convert the related analog signals into pulse signals, and completes the correction (elimination) of the ambient light noise and the optical crosstalk noise by matching with a specially designed correction formula based on the mode of calculating the pulse number of the pulse signals.
Description
Technical Field
The present invention relates to the field of Optical sensing (Optical sensing), and more particularly, to a method for performing a noise cancellation process on ambient light and crosstalk using an Optical frequency conversion technique.
Background
With the high development of smart phones, the smart phone is no longer a simple communication tool; in particular, after Augmented Reality (AR) and Virtual Reality (VR) technologies are widely applied to smart phones, the smart phones are just as indispensable electronic products in daily life. Several basic sensors are configured inside the smart phone, including: fingerprint sensor, ambient light sensor, near object sensor, gravity sensor, acceleration sensor, gyroscope, and global positioning system.
A Proximity Sensor (PS) is also called proximity sensor, and is usually integrated with the ambient light sensor in the same Optical sensing module. At present, the proximity sensor is not only applied to a smart phone to detect whether the face of a user is close to the screen of the smart phone, but also widely applied to the technical fields of non-contact inductive switch devices, limit switches (or micro switches), tamper detection (pointer detection), Time of Flight (ToF), and the like. For example, an apple bluetooth headset (airpots) is equipped with a non-contact inductive switch device, and the non-contact inductive switch device is the above-mentioned proximity sensor.
Fig. 1 is a side sectional view showing a conventional optical sensing module. As shown in fig. 1, the optical sensing module 2' includes: a circuit substrate 21 ', a light emitting device 22 ', a light receiving unit 23 ', and a control and processing unit (not shown); the light emitting device 22 'and the light receiving unit 23' are accommodated in an accommodating body 26 ', and the accommodating body 26' is provided with a light emitting opening LOO 'and a light receiving opening LRO' for exposing the light emitting device 22 'and the light receiving unit 23'.
When the near object sensing function is performed, the control and processing unit controls the light emitting device 22 ' to emit a detecting light 31 ' to an object 3 ' and receive a first reflected light 32 ' from the object 3 '. At this time, a cover plate 15 'located above the accommodating body 26' will usually reflect a second reflected light 151 'to the light receiving unit 23' at the same time. Depending on the packaging method, the cover plate 15 'may be an acrylic cover plate of the optical sensing module 2' or a glass plate on the top of the smart phone. Importantly, the second reflected light 151 ' becomes Optical crosstalk noise (Optical crosstalk), which results in that the control and processing unit at the back end cannot correctly calculate the degree of the object 3 ' approaching the Optical sensing module 2 '.
In order to eliminate the optical crosstalk, many technical solutions have been disclosed and proposed. For example, U.S. patent publication nos. US20140252212a1 and US20180203101a1 reduce the influence of optical crosstalk on the proximity sensing function of the optical sensing module 2' by circuit design. On the other hand, the US patent publication No. US20160356642a1 is intended to effectively eliminate the optical crosstalk by changing the structural design of the housing 26'.
Although these three prior arts do help to reduce the effect of optical crosstalk on the function of sensing the near object of the optical sensing module 2 ', the effect of the Ambient light 152 ' (Ambient light) cannot be eliminated, because the intensity of the Ambient light 152 ' is much larger than the intensities of the first reflected light 32 ' from the object 3 ' and the second reflected light 151 ' from the cover 15 '. On the other hand, it should be known to the electrical engineers familiar with the design and fabrication of proximity sensors and ambient light sensors that US20160356642a1 uses an Optical barrier (Optical barrier) to block the amount of second reflected light 151 '(shown in fig. 1) passing through the light-receiving opening LRO'. However, the overall thickness of the container 26' cannot be controlled within 0.75-1mm due to the fact that the optical barrier typically has a certain height. It is easy to understand that the optical sensing module 2 'with the accommodating body 26' having a high optical barrier is difficult to be applied to portable electronic products requiring lightness, thinness, shortness and smallness. However, if the optical barrier is not designed in the accommodating body 26 ', the optical crosstalk may also be generated inside the optical sensing module 2', so that the electronic engineer must design more complicated circuits or algorithms to solve the various optical crosstalk derived under different conditions.
From the above description, it can be seen how to improve the circuit structure of the control and processing unit of the conventional optical proximity sensor so that the optical proximity sensor can eliminate the optical crosstalk noise and the ambient light noise derived from various situations, and thus the improvement is a major issue for manufacturers of optical sensing modules. In view of the above, the present inventors have made extensive studies and finally have developed a method for eliminating ambient light and optical crosstalk of an optical proximity sensing device using an optical frequency conversion technique according to the present invention.
Disclosure of Invention
The main objective of the present invention is to provide a method for eliminating ambient light and optical crosstalk of an optical proximity sensing apparatus, which particularly utilizes a light frequency conversion technique to eliminate ambient light and optical crosstalk of the optical proximity sensing apparatus. In the present invention, a control and processing circuit, a light emitting unit, a light receiving unit, a digital-to-analog conversion module, an analog adder, and a light-to-digital conversion module together form an optical proximity sensing device. Then, the method of the present invention controls the plurality of electronic units to perform a noise cancellation process on an ambient light signal and/or an optical crosstalk signal using a light frequency conversion technique during a light emitting period and a turn-off period of the light emitting unit. Particularly, the invention uses the optical digital conversion module to convert the related analog signals into pulse signals, and completes the correction (elimination) of the ambient light noise and the optical crosstalk noise by matching with a specially designed correction formula based on the mode of calculating the pulse number of the pulse signals.
Therefore, to achieve the above-mentioned primary objective of the present invention, the present inventors provide an embodiment of the method for eliminating ambient light and optical crosstalk, which includes the following steps:
(1) an optical proximity sensing device is composed of a control and processing circuit, a light emitting unit, a light receiving unit, a digital-analog conversion module, an analog adder and a light-digital conversion module;
(2) during a turn-off period of the light-emitting unit, the control and processing circuit controls the light-receiving unit, the analog adder and the optical digital conversion module to work, so that the light-receiving unit provides a first photocurrent signal only containing an ambient light component to the analog adder, the analog adder then outputs a first analog current signal to the optical digital conversion module, and the optical digital conversion module converts the first analog current signal into a first pulse signal first, and then converts the first pulse signal into a first digital signal for expressing a first pulse number;
(3) during a light emitting period of the light emitting unit, the control and processing circuit controls the light emitting unit, the light receiving unit, the digital-to-analog conversion module, the analog adder and the light-to-digital conversion module to work, so that the light receiving unit provides a second photocurrent signal which simultaneously contains the ambient light component, an object reflected light component and an optical crosstalk component to the analog adder, and the control and processing circuit simultaneously generates a first binary code signal based on the first digital signal to control the digital-to-analog conversion module to output a first compensation current signal to the analog adder; the analog adder then outputs a second analog current signal to the optical digital conversion module, and the optical digital conversion module converts the second analog current signal into a second pulse signal first, and then converts the second pulse signal into a second digital signal for expressing a second number of pulses;
(4) during the light emitting period of the light emitting unit, the control and processing circuit further generates a second binary code signal based on the first digital signal and the second digital signal to control the digital-to-analog conversion module to simultaneously output a second compensation current signal to the analog adder; the analog adder then outputs a third analog current signal to the optical digital conversion module, and the optical digital conversion module converts the third analog current signal into a third pulse signal first, and then converts the third pulse signal into a third digital signal for expressing a third pulse number; and
(5) the control and processing circuit determines whether the optical crosstalk component has been cancelled based on the first digital signal, the second digital signal, and the third digital signal; if yes, the step is ended; if not, repeating the step (3) and the step (4).
In an embodiment of the method for eliminating ambient light and optical crosstalk, the digital-to-analog conversion module includes:
a first digital-to-analog conversion unit electrically connected to the control and processing circuit and outputting the first compensation current signal based on the first binary code signal of the control and processing circuit; and
and the second digital-analog conversion unit is electrically connected to the control and processing circuit and outputs the second compensation current signal based on the second binary code signal of the control and processing circuit.
In an embodiment of the method for eliminating ambient light and optical crosstalk, the resolutions of the first digital-to-analog conversion unit and the second digital-to-analog conversion unit are m bits and n bits, respectively, where n < m.
In an embodiment of the method for canceling ambient light and optical crosstalk according to the present invention, the first compensation current signal is used for canceling the ambient light component, and the second compensation current signal is used for canceling the optical crosstalk component.
In an embodiment of the method for eliminating the ambient light and the optical crosstalk, the optical digital conversion module includes an optical frequency conversion unit and a pulse counter coupled to the optical frequency conversion unit.
Drawings
FIG. 1 shows a side cross-sectional view of a prior art optical sensing module;
FIG. 2 is a block diagram of an optical proximity sensing apparatus for self-compensating for ambient light and crosstalk using optical frequency conversion techniques in accordance with the present invention;
FIGS. 3A and 3B are flow charts illustrating a method of eliminating ambient light and optical crosstalk of an optical proximity sensing apparatus using a light frequency conversion technique according to the present invention; and
fig. 4 shows waveforms of a plurality of sets of signals.
Wherein the reference numerals are:
1 optical proximity sensing device
10 control and processing circuit
LE light emitting unit
LR light receiving unit
11 analog adder
DA digital-to-analog conversion module
D1 first digital-to-analog conversion unit
D2 second digital-to-analog conversion unit
12 light digital conversion module
13 drive unit
Method steps S1-S5
121 optical frequency conversion unit
122 pulse counter
A signal
B signal
C signal
D signal
E signal
2' optical sensing module
3' object
21' circuit substrate
22' light emitting element
23' light receiving unit
26' container
15' cover plate
LOO' light exit opening
LRO' light-receiving opening
31' detecting light
32' first reflected light
151' second reflected light
152' ambient light
Detailed Description
In order to more clearly describe a method for eliminating ambient light and optical crosstalk of an optical proximity sensing apparatus by using an optical frequency conversion technique, a preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.
FIG. 2 is a block diagram of an optical proximity sensing apparatus for self-compensating for ambient light and crosstalk using optical frequency conversion techniques according to the present invention. As shown in fig. 2, the optical proximity sensing apparatus 1 of the present invention mainly utilizes an optical frequency conversion technique to perform self-compensation on an ambient light signal and an optical crosstalk signal, i.e., utilizes the optical frequency conversion technique to eliminate noise derived from the ambient light and the optical crosstalk. It is particularly emphasized that the optical proximity sensing apparatus 1 of the present invention can be manufactured independently, or can be integrated with an ambient light sensing apparatus to form an optical sensing module. In addition, the optical proximity sensing apparatus 1 of the present invention is not only applied to a smart phone to detect whether the face of the user is close to the screen of the smart phone, but also widely applied to the technical fields of non-contact inductive switch devices, limit switches (or micro switches), tamper detection (pointer detection), Time of Flight (ToF), etc.
The optical proximity sensing apparatus 1 of the present invention includes: a control and processing circuit 10, a light emitting unit LE, a light receiving unit LR, an analog adder 11, a digital-to-analog conversion module DA including a first digital-to-analog conversion unit D1 and a second digital-to-analog conversion unit D2, an optical-to-digital conversion module 12, and a driving unit 13. The driving unit 13 is coupled to the control and processing circuit 10 and the light emitting unit LE, and is configured to control the light emitting unit LE to emit a detection light to an object according to a driving signal of the control and processing circuit 10. The light receiving unit LR is used for receiving an object reflection light from the object and correspondingly generating an object reflection light current signal.
Prior art, for example: U.S. patent publication No. US20140252212a1 uses an analog front end circuit (AFE circuit) to convert the object reflected photocurrent signal into a voltage signal. Since the object reflected light current signal may include both an optical crosstalk signal (CT signal) and an Ambient light signal (Ambient light signal), the US patent publication No. US20140252212a1 uses a comparator to compare the voltage signal with a threshold voltage, so as to achieve the purpose of eliminating the optical crosstalk noise and the Ambient light noise. Unlike the prior art, the present invention mainly employs an analog adder 11, a first digital-to-analog conversion unit D1, a second digital-to-analog conversion unit D2, and an optical-to-digital conversion module (Light-to-digital conversion module)12 to eliminate the optical crosstalk noise and the ambient Light noise.
Fig. 3A and 3B are flow charts illustrating a method for eliminating ambient light and optical crosstalk of an optical proximity sensing apparatus using an optical frequency conversion technique according to the present invention. Referring to the circuit block diagram of fig. 2, the method of the present invention mainly includes the following 5 steps. In step S1, the optical proximity sensing apparatus 1 is composed of a control and processing circuit 10, a light emitting unit LE, a light receiving unit LR, a digital-to-analog conversion module DA, an analog adder 11, and a light-to-digital conversion module 12. As shown in fig. 2, the digital-to-analog conversion module DA includes a first digital-to-analog conversion unit D1 and a second digital-to-analog conversion unit D2, and the optical digital conversion module 12 includes an optical frequency conversion unit 121 and a pulse counter 122 coupled to the optical frequency conversion unit 121. Specifically, the first digital-to-analog converting unit D1 and the second digital-to-analog converting unit D2 are both current-mode digital-to-analog converters, and are configured to generate a first compensation current signal and a second compensation current signal respectively for eliminating ambient light noise and optical crosstalk noise. Fig. 4 shows waveforms of a plurality of sets of signals. In fig. 4, a signal a is a driving signal for controlling the light emitting unit LE, a signal B is a pulse signal output by the optical frequency conversion unit 121, a signal C is a second compensation current signal output by the second digital-to-analog conversion unit D2, a signal D is the pulse count signal output by the pulse counter 122, and a signal E is the pulse count signal finally output by the pulse counter 122 (i.e., the optical digital conversion module 12) to the control and processing circuit 10.
After the step S1 is completed, the method of the present invention then executes a step S2, in which the control and processing circuit 10 controls the light receiving unit LR, the analog adder 11, and the optical digital conversion module 12 to operate during a turn-off period of the light emitting unit LE, so that the light receiving unit LR provides a first photocurrent signal only including an ambient light component to the analog adder 11, the analog adder 11 then outputs a first analog current signal to the optical digital conversion module 12, and the optical digital conversion module 12 converts the first analog current signal into a first pulse signal, and then converts the first pulse signal into a first digital signal for expressing a first pulse number. It is easy to understand that when the light emitting unit LE enters the OFF period (the "OFF" period marked by the signal a in fig. 4), the light emitting unit LE does not emit any light; at this time, it can be confirmed that the photocurrent signal output from the light receiving unit LR contains only the ambient light signal. Further, it can be clearly known from observing the signal a (driving signal), the signal B (pulse signal) and the signal D (pulse counting signal), that in the first off period of the light emitting unit LE, the optical frequency conversion unit 121 converts the analog current signal into the corresponding pulse signal, and then the pulse counter 122 counts the number of pulses contained in the pulse signal. Therefore, we can know from fig. 4 that the number of pulses counted is 3 (this is an exemplary embodiment).
After step S2 is completed, the method of the present invention then executes step S3. during a light emitting period of the light emitting unit LE, the control and processing circuit 10 controls the light emitting unit LE, the light receiving unit LR, the digital-to-analog conversion module DA, the analog adder 11, and the optical-to-digital conversion module 12 to operate, such that the light receiving unit LR provides a second photocurrent signal including the ambient light component, an object reflected light component, and an optical crosstalk component to the analog adder 11, and the control and processing circuit 10 generates a first binary code signal based on the first digital signal to control the digital-to-analog conversion module DA to output a first compensation current signal to the analog adder 11; the analog adder 11 then outputs a second analog current signal to the optical digital conversion module 12, and the optical digital conversion module 12 first converts the second analog current signal into a second pulse signal, and then converts the second pulse signal into a second digital signal for expressing a second number of pulses. To describe in more detail, during the light emitting period of the light emitting unit LE, the first digital-to-analog converting unit D1 outputs the first compensation current signal to eliminate the ambient light component based on the first binary code signal of the control and processing circuit 10. Therefore, as shown by the signal E in fig. 4, the pulse count signal finally outputted from the pulse counter 122 (i.e., the optical digital conversion module 12) to the control and processing circuit 10 indicates that a corrected number of pulses is 11-3-8.
After completing step S3, the method of the present invention proceeds to step S4. during the light emitting period of the light emitting unit LE, the control and processing circuit 10 further generates a second binary code signal based on the first digital signal and the second digital signal to control the digital-to-analog converting module DA to output a second compensating current signal to the analog adder 11; the analog adder 11 then outputs a third analog current signal to the optical digital conversion module 12, and the optical digital conversion module 12 first converts the third analog current signal into a third pulse signal, and then converts the third pulse signal into a third digital signal for expressing a third number of pulses. It should be specifically explained that, as shown in fig. 4, the first pulse signal and the second pulse signal constitute a continuous pulse signal (i.e., signal B) during the continuous on/off period of the light emitting unit LE. In brief, the first pulse signal, the second pulse signal and the third pulse signal referred to in steps S2, S3 and S4 do not mean that the three groups of pulse signals are independent, and actually, the three groups of pulse signals are a group of continuous pulse signals (i.e., signal B) in consecutive on/off periods of the light emitting unit LE. In the same way, in the continuous on/off period of the light emitting unit LE, the first photocurrent signal and the second photocurrent signal form a continuous photocurrent signal, the first analog current signal and the second analog current signal form a continuous analog current signal, and the first digital signal and the second digital signal form a continuous digital signal (i.e., signal E).
During the light emitting period of the light emitting unit LE, the control and processing circuit 10 simultaneously sends a set of second binary code signals to control the second digital-to-analog converting unit D2 to output the second compensation current signal, and the output of the second compensation current signal eliminates the optical crosstalk component in the second photocurrent signal in the analog adder 11. As can be seen from the signal C in fig. 4, the control and processing circuit 10 controls the second digital-to-analog converting unit D2 to output the second compensation current according to the binary code signal with the enable bit number n being 3. Of course, after receiving the first compensation current of the first digital-to-analog converting unit D1, the second compensation current of the second digital-to-analog converting unit D2, and the photo current signal provided by the light receiving unit LR at the same time, the analog adder 11 then outputs a third analog current signal to the optical-to-digital converting module 12, and the optical-to-digital converting module 12 first converts the third analog current signal into a third pulse signal, and then converts the third pulse signal into a third digital signal for expressing a third pulse number. Therefore, as shown in signal E of fig. 4, when entering the next off period of the light emitting unit LE, the pulse count signal outputted by the pulse counter 122 (i.e. the optical digital conversion module 12) to the control and processing circuit 10 indicates that a corrected number of pulses is 8+ 7-15.
After completing step S4, the method of the present invention proceeds to step S5, in which the control and processing circuit 10 determines whether the optical crosstalk component has been eliminated based on the first digital signal, the second digital signal, and the third digital signal; if yes, the step is ended; if not, the steps S3 and S4 are repeated. The control and processing circuit 10 determines whether the optical crosstalk and/or the ambient light component in the photocurrent signal transmitted by the light-receiving unit LR have been eliminated according to the following calibration formula. Generally, the ambient light noise can be completely eliminated through steps S2 and S3, and the optical crosstalk may have to pass through the light emitting period of one or more of the light emitting cells LE before being eliminated by the following correction formula.
NpuC*PpuW[TW*L2FOUT(DACCT＝n,DACAMB＝m)-TC*L2FOUT(DACCT＝0,DACAMB＝m)]
In the above correction formula, TWFor the light emitting period, TCFor the off period, PpuWIs the signal energy, N, during the emissionpuCIs the number of consecutive turn-off times of the light emitting cells, m is the number of enabled bits of the first digital-to-analog converting unit D1, and n is the number of enabled bits of the second digital-to-analog converting unit D2.
In brief, the optical proximity sensing apparatus 1 of the present invention completes the intensity determination of the Ambient light (Ambient light) noise by using the first digital-to-analog converting unit D1, the optical digital converting module 12, and the control and processing circuit 10 during the first off period and the first light emitting period of the light emitting unit LE. Further, after the light emitting time is reached, the optical proximity sensing apparatus 1 further utilizes the first digital-to-analog converting unit D1, the second digital-to-analog converting unit D2, the optical-to-digital converting module 12, and the control and processing circuit 10 to simultaneously complete the elimination of the ambient light and the optical crosstalk noise based on the above-mentioned correction formula.
It should be emphasized that the above detailed description is specific to possible embodiments of the invention, but this is not to be taken as limiting the scope of the invention, and all equivalent implementations or modifications that do not depart from the technical spirit of the invention are intended to be included within the scope of the present invention.
Claims (10)
1. A method for canceling ambient light and optical crosstalk of an optical proximity sensing device, comprising the steps of:
(1) an optical proximity sensing device is composed of a control and processing circuit, a light emitting unit, a light receiving unit, a digital-analog conversion module, an analog adder and a light-digital conversion module;
(2) during a turn-off period of the light-emitting unit, the control and processing circuit controls the light-receiving unit, the analog adder and the optical digital conversion module to work, so that the light-receiving unit provides a first photocurrent signal only containing an ambient light component to the analog adder, the analog adder then outputs a first analog current signal to the optical digital conversion module, and the optical digital conversion module converts the first analog current signal into a first pulse signal first, and then converts the first pulse signal into a first digital signal for expressing a first pulse number;
(3) during a light emitting period of the light emitting unit, the control and processing circuit controls the light emitting unit, the light receiving unit, the digital-to-analog conversion module, the analog adder and the light-to-digital conversion module to work, so that the light receiving unit provides a second photocurrent signal which simultaneously contains the ambient light component, an object reflected light component and an optical crosstalk component to the analog adder, and the control and processing circuit simultaneously generates a first binary code signal based on the first digital signal to control the digital-to-analog conversion module to output a first compensation current signal to the analog adder; the analog adder then outputs a second analog current signal to the optical digital conversion module, and the optical digital conversion module converts the second analog current signal into a second pulse signal first, and then converts the second pulse signal into a second digital signal for expressing a second number of pulses;
(4) during the light emitting period of the light emitting unit, the control and processing circuit further generates a second binary code signal based on the first digital signal and the second digital signal to control the digital-to-analog conversion module to simultaneously output a second compensation current signal to the analog adder; the analog adder then outputs a third analog current signal to the optical digital conversion module, and the optical digital conversion module converts the third analog current signal into a third pulse signal first, and then converts the third pulse signal into a third digital signal for expressing a third pulse number; and
(5) the control and processing circuit determines whether the optical crosstalk component has been cancelled based on the first digital signal, the second digital signal, and the third digital signal; if yes, the step is ended; if not, repeating the step (3) and the step (4).
2. The method of claim 1, wherein the digital-to-analog conversion module comprises:
a first digital-to-analog conversion unit electrically connected to the control and processing circuit and outputting the first compensation current signal based on the first binary code signal of the control and processing circuit; and
and the second digital-analog conversion unit is electrically connected to the control and processing circuit and outputs the second compensation current signal based on the second binary code signal of the control and processing circuit.
3. The method as claimed in claim 2, wherein the resolutions of the first digital-to-analog converting unit and the second digital-to-analog converting unit are m bits and n bits, respectively, and n < m.
4. The method of claim 2, wherein the first compensation current signal is used to cancel the ambient light component and the second compensation current signal is used to cancel the optical crosstalk component.
5. The method as claimed in claim 1, wherein during a continuous on/off cycle of the light-emitting unit, the first photocurrent signal and the second photocurrent signal form a continuous photocurrent signal, the first analog current signal and the second analog current signal form a continuous analog current signal, the first pulse signal and the second pulse signal form a continuous pulse signal, and the first digital signal and the second digital signal form a continuous digital signal.
6. The method as claimed in claim 1, wherein the optical digital conversion module comprises an optical frequency conversion unit and a pulse counter coupled to the optical frequency conversion unit.
7. The method as claimed in claim 1, wherein the optical proximity sensing apparatus further comprises a driving unit coupled between the control and processing circuit and the light emitting unit for controlling the light emitting unit to emit the detection light according to the driving signal.
8. The method of claim 2, wherein the first DAC unit and the second DAC unit are both current-mode DACs.
9. The method of claim 1, wherein the light emitting unit is a light emitting diode or an organic light emitting diode, and the control and processing circuit is a microprocessor.
10. The method of claim 1, wherein the optical proximity sensing apparatus is integrated with an ambient light sensing apparatus into an optical sensing module.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114545811A (en) * | 2020-11-26 | 2022-05-27 | 神煜电子股份有限公司 | Proximity sensing device |
| CN114827346A (en) * | 2021-01-28 | 2022-07-29 | 昇佳电子股份有限公司 | Control method of proximity sensor |
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