JP6111098B2 - Optical sensor - Google Patents

Description

  The present invention relates to an optical sensor that receives, for example, light emitted from a light emitting element and reflected by a detection object by a light receiving element, and detects the presence or absence of the detection object based on an output of the light receiving element.

  For example, a reflection type optical sensor composed of a light emitting element and a light receiving element is used to detect whether a document is set in a copying machine. This is configured to detect the presence / absence of a document based on the presence / absence of light reflected from the document and incident on the light receiving element out of the light projected from the light emitting element. Light other than the light-emitting element may enter the light-receiving element as disturbance light and adversely affect detection accuracy.

  In order to eliminate the influence of such disturbance light and improve the detection accuracy of a detection target such as a document, the reflection type optical sensor described in Patent Document 1 is configured so that the light receiving element does not emit light. The presence or absence of disturbance light is determined from the output, and when it is determined that there is disturbance light, it is determined that there is no detection target.

  More specifically, as shown in FIG. 7 (a), the reflection type optical sensor acquires an output from the light receiving element with a light receiving clock having a predetermined period, and has a cycle twice that of the light receiving clock, The light emitting element is configured to emit pulses with a light emission clock whose phase is aligned with that of the light reception clock. And the presence or absence of a detection target is determined at the timing when the light emitting element emits light, and the presence or absence of disturbance light is determined at the timing when the light emitting element does not emit light.

  Since it is configured in this manner, as shown in FIGS. 7B and 7C, when it is determined that there is no output from the light receiving element at the timing when the light emitting element is not emitting light and there is no disturbance light. Only when there is an output from the light receiving element at the timing when the light emitting element emits light, it is determined that there is an object to be detected. Further, in the state where it is determined that there is disturbance light as shown in FIG. 7D, the non-detection determination is made even when there is an output from the light receiving element at the timing when the light emitting element emits light. .

  By the way, if it is configured such that the determination of the presence / absence of the detection target and the determination of the presence / absence of disturbance light are repeated alternately for each one clock, as shown in FIG. When disturbance light of a frequency, for example, light from an inverter fluorescent lamp or the like is received by the light receiving element, the output pattern from the light receiving element is the detection pattern as shown in FIG. May match. That is, as shown in FIG. 7 (e), there is a risk of erroneous detection in which detection determination is made despite the absence of a detection target, and even the reflective optical sensor described in Patent Document 1 is a disturbance. It cannot be said that the resistance to light is sufficient.

  In addition, as shown in FIG. 7D, while disturbance light is entering the light receiving element, even if there is an output from the light receiving element at the timing when the light emitting element emits light, the detection target is always present. The determination of the presence or absence of the detection target is repeated, although the determination is made that there is no detection. And since the state of disturbance light rarely changes in a very short time, in most cases, the result of non-detection is continued for a while. That is, when there is disturbance light, etc., the determination result is almost fixed for a predetermined period, but the operation of the light receiving element and the light emitting element is meaninglessly repeated to waste power. It will be.

  For example, when a reflective optical sensor is used as a proximity sensor to switch between a call mode and a touch operation mode on a smartphone with limited battery capacity, the above-described waste of power consumption is avoided while preventing malfunction due to ambient light. Must be kept as low as possible.

Japanese Patent No. 3491868

  The present invention has been made in view of the above-described problems, and is an optical sensor capable of significantly reducing current consumption while improving resistance to disturbance light and preventing erroneous detection of the presence or absence of a detection target. The purpose is to provide.

That is, the optical sensor according to the first aspect of the present invention includes a light emitting element that projects light onto a detection target, a light receiving element that receives light or disturbance light from the detection target, and a light receiving element from the light receiving element. A determination unit that determines the presence or absence of a detection target based on the output, and the determination unit acquires the output from the light receiving element one or more times with a predetermined light receiving clock without causing the light emitting element to emit light. Then, a disturbance light monitor that determines the presence or absence of disturbance light based on the output is executed, and after the disturbance light monitor is executed, the light emitting element is pulse-driven one or more times with a light emission clock that coincides with the light reception clock. The self-projection monitor that determines the presence / absence of the detection object based on the output of the light receiving element at the time of each pulse emission is configured to execute, and there is disturbance light in the disturbance light monitor When it is determined, or when it is determined that the detection target is not present in the self-projection monitor, it is configured to shift to a pause mode in which at least the pulse driving of the light emitting element after that point is stopped is shifted to a predetermined period. The determination unit repeats a burst having the disturbance light monitor and the self-projection monitor as a unit a plurality of times, and is based on a determination result of the presence or absence of the detection target in the self-projection monitor of each burst. When a transition is made to a pause mode in a certain burst, the presence / absence of the detection object is determined after the pause mode is continued for a predetermined number of bursts thereafter. It is comprised as follows.

  In such a case, when it is determined that there is disturbance light when the disturbance light monitor is executed, the mode shifts to a pause mode in which the pulse driving of the light emitting element is stopped. The next self-projection monitor that has a high possibility that the presence or absence of the detection target cannot be accurately determined can be substantially prevented from being executed.

  In other words, unless the condition that the ambient light monitor immediately before the self-projection monitor is executed is determined not to have ambient light and the transition to the sleep mode is not performed, the self-projection monitor is not established. Therefore, the presence / absence of the detection target can always be determined in the absence of disturbance light, and the tolerance of detection accuracy against disturbance light can be increased.

  In addition, when it is determined that there is disturbance light in the disturbance light monitor, since the pulse driving of the light emitting element is not performed for a predetermined period during the predetermined period thereafter, there is only an inaccurate determination because there is disturbance light. It is possible to reduce current consumption due to useless operation in situations where it is impossible.

  Further, even when the self-projection monitor is executed, even if it is determined that there is no object to be detected in the middle of the operation, the subsequent pulse driving of the light emitting element is suspended, thereby further preventing unnecessary pulse emission and current consumption. Can be reduced.

After the time when it is determined that there is ambient light at the time of execution of the disturbance light monitor, or after the time when it is determined that there is no detection target at the time of execution of the self-projection light monitor, further wasteful operation is further eliminated, In order to further reduce the above, it is sufficient that the determination unit pauses at least the operation of the light receiving element in the pause mode as in the invention described in claim 2. In such a case, not only the current consumption in the self-projection monitor but also the current consumption in the disturbance light monitor in which the light emitting element is not pulse-driven can be reduced, so that the energy saving effect can be further enhanced.

In order to further reduce the current consumption , the light receiving element, a light receiving signal AC amplifier that amplifies and outputs an AC component of the output of the light receiving element, and the light receiving element as in the invention of claim 3 a comparator for comparing the predetermined threshold with the output from the signal AC amplifier, constitutes a light receiving portion, the determination unit may be Re was also paused the light receiving portion in the dormant mode.

  When the ambient light monitor is executed, the ambient light monitoring standard is made stricter, and the possibility of early transition to the sleep mode from the middle of the ambient light monitor is increased, thereby eliminating wasteful determination operations and further reducing current consumption. In order to reduce, as in the invention described in claim 4, the determination unit determines that there is disturbance light when there is an output from the light receiving element when the disturbance light monitor is executed, and after that point, What is necessary is just to be comprised so that it may transfer to hibernation mode.

  As described above, when the self-projection monitor is executed, the criterion for the presence / absence of the detection target is made stricter, and the possibility of shifting to the sleep mode from the middle of the self-projection monitor is increased. In order to increase the power of the light receiving element, when the determination unit has no output from the light receiving element at the time of execution of the self-projection monitor as in the invention of claim 5, It is only necessary to be configured so as to make a determination and shift to the pause mode after that time.

  Although it is determined that there is no ambient light at the time of executing the ambient light monitor, even when ambient light that is periodically lit from the time of executing the self-projection monitor enters the light receiving element, The invention according to claim 6, wherein a part of the light receiving clock is deviated so that no output is detected from the light receiving element when there is no object to be detected and no erroneous detection occurs. In addition, it is only necessary that at least a part of the light emission clock and the light reception clock in the self-projection light monitor deviate from the period of the light reception clock in the disturbance light monitor.

  As described above, according to the optical sensor of the present invention, when it is determined that there is disturbance light at the time of disturbance light monitor execution, the mode is shifted to the pause mode for a predetermined period, and the light emitting element is not pulse-driven. In the presence of ambient light, the self-projection monitor can be executed in the first place so that the presence / absence of the detection target is not determined. Therefore, since the self-projection monitor is executed only in a state where there is no disturbance light, the light emitted from the light emitting element without being influenced by the disturbance light is reflected by the detection target, and the light receiving element is reflected on the light receiving element. Only the output when incident can be obtained. For this reason, the determination accuracy of the presence or absence of the detection target can be made extremely high. In addition, in the presence of ambient light, an inaccurate determination result may be obtained, and the presence / absence of a detection target is not determined by a self-projection monitor that has little meaning to execute, so that useless operations are suspended. Current consumption can be reduced. In addition, since it is determined that there is no object to be detected, useless pulse driving of the light emitting element is not performed, so that the current consumption can be further reduced.

The schematic diagram which shows the structure of the optical sensor which concerns on 1st Embodiment of this invention. The typical functional block diagram which shows the specific structure of the determination part in 1st Embodiment. The schematic diagram which shows the operation | movement regarding the detection of the presence or absence of disturbance light in the 1st Embodiment, and the detection target object, and the operation | movement regarding transfer to a sleep mode. The schematic diagram shown about the determination result of the output of the light receiving element on the various conditions in 1st Embodiment, and the presence or absence of a detection target. The simulation result regarding the reduction amount of the consumption current in 1st Embodiment. The schematic diagram which shows the operation | movement regarding the detection of the presence or absence of the disturbance light which concerns on 2nd Embodiment of this invention, and a detection target, and the operation | movement regarding transfer to a sleep mode. The schematic diagram which shows the operation | movement regarding the detection of the presence or absence of disturbance light and the detection target in the conventional optical sensor.

  A reflective optical sensor 100 according to a first embodiment of the present invention will be described with reference to FIGS.

  The reflective optical sensor 100 according to the first embodiment is also used as a proximity sensor for switching between a call mode and a touch panel operation mode in a smartphone, and as a document sensor such as a human sensor or a copy machine.

  As shown in FIGS. 1 and 2, the reflective optical sensor 100 includes a light emitting element 1 that projects light in a predetermined direction, a light receiving element 2 provided in the vicinity of the light emitting element 1, and the light receiving element 2. It is comprised from the determination part 3 which determines whether the detection target P exists in the vicinity of the said light receiving element 2 based on the output from.

  As shown in FIG. 1, the light emitting element 1 and the light receiving element 2 are provided close to each other so as to form a substantially mirror image object. When the detection target P is present, the light receiving element 2 is the light emitting element. The light emitted from 1 is reflected by the detection object P and is incident on the light receiving element 2.

  The determination unit 3 includes a disturbance light monitor that determines the presence or absence of disturbance light based on the output of the light receiving element 2 without causing the light emitting element 1 to emit light, and the light receiving element 2 when the light emitting element 1 emits light. When the self-projection monitor that determines the presence or absence of the detection target P based on the output of the burst is repeated a plurality of times, and it is determined that there is the detection target P in the self-projection monitor of each burst. It is configured to determine that there is a detection object P as a final determination result. In each burst, the output from the light receiving element 2 is obtained discretely with a light receiving clock having a predetermined cycle, and the presence or absence of disturbance light and the detection object P are detected for each output. The presence / absence determination is performed. In the first embodiment, the determination unit 3 is configured to acquire the output from the light receiving element 2 at a maximum of 8 times per burst, and the self-projection is performed at a maximum of 4 times by the disturbance light monitor. The monitor outputs the output from the light receiving element 2 up to four times. It should be noted that after all eight acquisitions, the output from the light receiving element 2 is not acquired until the next burst is started.

  Furthermore, as a feature of the determination unit 3 of the first embodiment, when it is determined that there is disturbance light in the disturbance light monitor, or when it is determined that there is no detection object P in the self-projection monitor The light-emitting element 1, the light-receiving element 2, the light-receiving signal AC amplifier 34, which will be described later, and the light-receiving unit R (shown in FIG. 2) including the comparator 35, and other related operations The system is configured to shift to a sleep mode for pausing a predetermined period.

  The detailed operation of each monitor will be described.

  In the disturbance light monitor, as shown in FIG. 3, the output from the light receiving element 2 is acquired four times at maximum with a predetermined light receiving clock in a state where the light emitting element 1 does not emit light. Only when there is no output from the light receiving element 2 continuously, it is determined that there is no disturbance light while the disturbance light monitor is executed. In other words, in the disturbance light monitor, it is determined that there is disturbance light at the time when the output from the light receiving element 2 is received, and the mode is shifted to the sleep mode from that point.

  The self-projection monitor is executed only when it is determined that there is no disturbing light in the disturbance light monitor and does not enter the sleep mode, and the light receiving element continues with the same light receiving clock as the disturbance light monitor. The output from 2 is acquired up to 4 times. In this self-projecting monitor, the light emitting element 1 is pulse-emitted with a light emission clock synchronized with the light reception clock and having the same phase. The self-projection monitor is configured to determine that the detection target P is present only when there is an output from the light receiving element 2 for four consecutive times. In other words, the self-projection monitor determines that there is no detection target P when there is no output from the light receiving element 2, and shifts to the pause mode from that point.

  When shifting to the pause mode, first, in the first embodiment, the acquisition of the output from the light receiving element 2 that has not yet been executed in the burst and the pulse emission of the light emitting element 1 are paused. Further, the operation of at least the light emitting element 1 and the light receiving unit R is paused for a predetermined number of subsequent bursts, and then the normal determination operation is resumed. For example, when the disturbance light monitor determines that there is disturbance light, the number of bursts to be paused can be appropriately set according to the time required to change from the presence of disturbance light to the absence of disturbance light. . This time may be determined experimentally. The predetermined number, which is the number of bursts to be paused, is a concept including 0 times, 1 time, and multiple times.

  Next, a specific configuration of the determination unit 3 for executing the disturbance light monitor, the self-projection monitor, and the pause mode will be described.

  As shown in FIG. 2, the determination unit 3 includes at least an oscillation circuit 31, a pulse train generation circuit 32, a light emitting element drive circuit 33, a light receiving signal AC amplifier 34, a comparator 35, a signal processing circuit 36, and an output circuit 37. It is.

  The oscillation circuit 31 generates a reference timing for the light reception clock and the light emission clock, and the pulse train generation circuit 32 sends the light emission clock to the light emitting element drive circuit 33 based on the signal from the oscillation circuit 31. Is output. The light emitting element driving circuit 33 drives the light emitting element 1 in a pulse manner according to the input light emission clock.

  The light receiving signal AC amplifier 34 amplifies and outputs only the AC component of the output from the light receiving element 2. This is to eliminate the influence of the direct current component and prevent erroneous detection due to, for example, stationary light such as sunlight being determined as disturbance light.

  The comparator 35 compares the output from the light receiving signal AC amplifier 34 with a predetermined threshold value, and when the output exceeds the threshold value, 1 is set, and when the output does not exceed 0, the signal processing circuit 36 is set. Output to.

  As shown in FIG. 4, the signal processing circuit 36 outputs the outputs G1 to G4 from the light receiving element 2 in the first four bursts, that is, outputs OR from the light receiving element 2 when the disturbance light monitor is executed. To do. In addition, the outputs J1 to J4 from the light receiving element 2 in the latter half of the burst, that is, the outputs from the light receiving element 2 at the time of execution of the self-projection monitor are ANDed. In this way, in the disturbance light monitor, it is determined that there is no disturbance light only when the output from the light receiving element 2 is not all the light reception clocks, and in the self-projection monitor, all the outputs from the light receiving element 2 are received. Only when it is a clock, it is determined that the detection target P is present. In the pause mode, the signal processing circuit 36 always outputs a non-detection determination even when the light receiving unit R is not operating.

  The signal processing circuit 36 is configured to output that the detection target P is present as the final determination result when the detection results of the bursts are continuous and the detection target P is detected a predetermined number of times. The output circuit 37 is a drive circuit that supplies the determination result of the signal processing circuit 36 to the outside.

  A specific example of the operation of the reflective optical sensor 100 of the first embodiment will be described with reference to the timing chart of FIG. 3 and the determination result of FIG. The operations in FIGS. 3A to 3F and the determination results in FIGS. 4A to 4F are described so that the alphabets correspond to each other. 3A to 3F, 0 indicates that there is no output, 1 indicates that there is an output, and x indicates that there is no light reception output itself because the mode is shifted to the pause mode. The rectangular portion of the timing chart indicates that the light emitting element 1 emits pulse light.

  When there is no disturbance light and there is a detection target P, the determination unit 3 operates the light emitting element 1 and the light receiving element 2 with a reference light receiving clock and a light emitting clock as shown in FIG. Assumed. Actually, when there is disturbance light or when there is no detection target P, the operation shifts to the sleep mode, and the operation may not be performed according to the reference clock of FIG.

  First, the operation when there is no disturbance light and the detection target P is present will be described with reference to FIG. In this case, the operation is performed as expected in FIG. 3 (ST), and the burst ends without shifting to the sleep mode. And as for the determination regarding the presence or absence of the detection object P output from the determination part 3, the determination result that the detection object P exists is output as shown to Fig.4 (a).

  Next, a case where disturbance light is present will be described. As shown in FIG. 3B, when there is an output from the light receiving element 2 in the first light receiving clock of the disturbance light monitor, it is determined that there is disturbance light at that time, and the mode shifts to the sleep mode from that time. To do. Accordingly, as indicated by x in FIG. 3B, the operation of the light receiving unit R in the second and subsequent light receiving clocks of the disturbance light monitor, and the pulses of the light receiving unit R and the light emitting element 1 in the next self-projected light monitor. The light emission is also paused. In this example, since the output of the light receiving element 2 is output in the first light receiving clock, this operation is performed. For example, there is an output from the light receiving element 2 in the second, third, and fourth light receiving clocks of the disturbance light monitor. In this case, the operations of the light receiving unit R and the light emitting element 1 are suspended after that, as shown in FIG.

  Next, when there is no disturbance light and there is no detection target P, or there is a detection target P, the reflected light from the detection target P is weak, so there is no output from the light receiving element 2 for four consecutive times. Examples will be described with reference to FIGS. 3C to 3F and FIGS. 4C to 4F.

  The operation of the self-projection monitor as shown in FIGS. 3C to 3F is executed only when there is no output from the light receiving element 2 in the disturbance light monitor. As long as there is no output from the light receiving element 2 consecutively, it is determined that the detection target P is present. Therefore, when there is no output from the light receiving element 2 in the middle, the mode is shifted to the pause mode. That is, as shown in FIGS. 3C to 3F, when there is no output from the light receiving element 2 corresponding to the pulse light emission of the light emitting element 1, the operation of the light receiving unit R and the light emitting element 1 thereafter. To pause.

  Thus, the simulation result of FIG. 5 shows the effect of reducing current consumption by shifting to the sleep mode when it is determined that there is ambient light and when it is determined that there is no detection target P.

This simulation shows the amount of reduction caused by pausing the light emitting element 1 in the self-projection monitor. Even if the output from the light receiving element 2 is further acquired as shown in FIG. It can be seen that the current consumption can be reduced by up to about 50% during normal operation by pausing the subsequent operation in a state where it does not occur.

  As described above, according to the reflective optical sensor 100 of the first embodiment, when it is determined that the disturbance light is present when the determination unit 3 executes the disturbance light monitor, the mode shifts to the pause mode, and the following Since it is configured not to execute the self-projection monitor, the reflected light of the light projected from the light emitting element 1 to the detection target P in the absence of disturbance light is always reflected by the light receiving element 2 in the self-projection monitor. Whether or not light is received can be detected, and the presence or absence of the detection object P can be determined.

  Accordingly, since it is possible to determine whether or not the detection target P is present in a state where there is no influence of disturbance light, it is easy to eliminate erroneous detection.

  Further, as shown in FIG. 3 and the like, when the determination result in the disturbance light monitor and the self-projection monitor becomes the non-detection determination state, the mode shifts to the sleep mode, and the light receiving unit R including the light receiving element 2 and the light receiving unit 2 Since the operation of the light emitting element 1 is suspended, the current consumption can be reduced while enhancing the resistance to disturbance light.

  Next, a reflective photosensor 100 according to a second embodiment of the present invention will be described.

  In the first embodiment, the light reception clock and the light emission clock are always set at a fixed period in both the disturbance light monitor and the self-projection light monitor. In the second embodiment, as shown in FIG. In addition, the light receiving clock and the light emitting clock in the self-projecting monitor are partially hopped.

  That is, the determination unit 3 according to the second embodiment makes sure that at least a part of the light emission clock and the light reception clock in the self-projection monitor is out of the period of the light reception clock in the disturbance light monitor. ing.

  As can be seen by comparing the timing chart of the first embodiment shown in FIG. 6A and the timing chart of the second embodiment shown in FIG. 6B, the second embodiment uses a self-projection monitor. If the timing of the third light receiving clock is a fixed period, it is deviated from the timing that should originally exist.

  With this configuration, as shown in the bottom timing chart of FIG. 6B, there is no detection target P, and the period is synchronized with the period of the first and second light receiving clocks of the self-projection monitor. When disturbance light is incident, the disturbance light is not detected because it is incident on the light receiving element 2 immediately before the third light receiving clock, and reflected light from the detection object P is detected in the third light receiving clock. Therefore, there is no output from the light receiving element 2.

  In this way, even in the rare case where periodic disturbance light synchronized with a part of the period of the light receiving clock enters from the time when the self-projection monitor is started, if there is no detection target P, the detection is performed. It can be determined that there is no object P and erroneous detection is prevented.

  As described above, according to the reflective optical sensor 100 of the second embodiment, it is possible to further increase resistance to disturbance light and prevent erroneous detection.

  Other embodiments will be described.

In each of the above-described embodiments, both the light receiving unit R and the light emitting element 1 are paused in the pause mode. However, for example, only the light emitting element 1 may be paused. In addition, the parts related to the light receiving unit R and the light emitting element 1 that do not cause any problem in operation may be stopped in conjunction with each other. In the embodiment, all of the light receiving units R are suspended in the pause mode, but at least the light receiving element 2 may be paused. Even in such a case, current consumption can be reduced as compared with the conventional case.

  In the embodiment, the pause mode period is set in units of bursts. However, for example, the pause mode period may be set according to time, and may return to the normal mode after a predetermined time has elapsed. More specifically, the duration time of the sleep mode may be set so as to start from the middle state of the ambient light monitor, for example.

  Furthermore, the number of acquisitions of the output from the light receiving element 2 in the disturbance light monitor and the self-projection monitor is not limited to four times shown in each embodiment, and can be set to various acquisition times. It is not necessary to match the number of acquisitions in the monitor. It can be set as appropriate according to the required detection accuracy, the time required for detection, and the like. Further, the number of bursts necessary for outputting the final determination result may be set as appropriate.

  In each of the above embodiments, the disturbance light monitor has output from the light receiving element 2 even once as a condition for shifting to the sleep mode. For example, the condition is relaxed and the light receiving element is doubled in the disturbance light monitor. If there is an output from 2, it may be determined that there is ambient light, and the mode may be shifted to the sleep mode. In short, when it is determined that there is disturbance light in the disturbance light monitor and the determination result does not change even if sampling is continued further, the mode may be shifted to the sleep mode.

  In the above embodiment, the reflection type optical sensor 100 has been described as an example. However, the method of shifting to the sleep mode may be applied to the transmission type optical sensor 100 and the like.

  In addition, various modifications and combinations of embodiments may be performed without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Reflection type optical sensor 1 ... Light emitting element 2 ... Light receiving element 3 ... Determination part 31 ... Oscillation circuit 32 ... Pulse train generation circuit 33 ... Light emitting element drive circuit 34 ...・ Reception signal AC amplifier 35 ・ ・ ・ Comparator 36 ・ ・ ・ Signal processing circuit 37 ・ ・ ・ Output circuit R ・ ・ ・ Reception unit

Claims (6)

A light emitting element that projects light onto a detection object;
A light receiving element that receives light or disturbance light from the detection object;
A determination unit for determining the presence or absence of a detection object based on an output from the light receiving element,
The determination unit is
Obtain a plurality of outputs from the light receiving element with a predetermined light receiving clock without causing the light emitting element to emit light, and execute a disturbance light monitor that determines the presence or absence of disturbance light based on those outputs,
The light emitting element is pulse-driven one or more times with a light emission clock that coincides with the light reception clock after execution of the disturbance light monitor, and the presence or absence of the detection target is determined based on the output of the light reception element at the time of each pulse light emission. It is configured to run a self-projecting monitor to determine,
If the disturbance light monitor determines that there is disturbance light, or if the self-projection monitor determines that there is no detection object, at least the pulse driving of the light emitting element after that point is stopped. It is configured to enter the sleep mode for a predetermined period of time,
The determination unit repeats a burst having the disturbance light monitor and the self-projection monitor as a unit a plurality of times, and a final determination result based on the determination result of the detection target in the self-projection monitor of each burst Is configured to output
An optical sensor configured to perform the determination of the presence or absence of the detection target after continuing the pause mode for a predetermined number of bursts thereafter when the mode shifts to the pause mode in a certain burst . The optical sensor according to claim 1, wherein the determination unit pauses at least the operation of the light receiving element in the pause mode.   The light receiving element, a light receiving signal AC amplifier that amplifies and outputs an AC component of the output of the light receiving element, and a comparator that compares the output from the light receiving signal AC amplifier with a predetermined threshold value. Part
  The optical sensor according to claim 1, wherein the determination unit also pauses the light receiving unit in the pause mode.   The determination unit is configured to determine that there is disturbance light when there is an output from the light receiving element at the time of execution of the disturbance light monitor, and to shift to the pause mode after that point. 3. The optical sensor according to any one of 3.   The determination unit is configured to determine that there is no detection target at a time when there is no output from the light receiving element at the time of execution of the self-projection monitor, and to shift to the sleep mode after that time. The optical sensor according to claim 1. 6. The optical sensor according to claim 1, wherein at least a part of the light emission clock and the light reception clock in the self-projection monitor deviates from a period of the light reception clock in the disturbance light monitor.