JP2019132586A - Sensor and electronic device - Google Patents

Abstract

To provide a proximity sensor that hardly causes a malfunction due to external light even when strong external light is incident, and an electronic device including the sensor.SOLUTION: A proximity sensor and an electronic device including the proximity sensor, includes: a light emitting unit that intermittently emits infrared light at predetermined time intervals; a light receiving unit that receives infrared light that is emitted from the light emitting unit and reflected back from the object; and a detection unit for detecting a received light signal level at the light receiving unit. The detection unit outputs a received light signal level at the light receiving unit during an infrared light emission period as a first detection result, and further, as a second detection result, outputs the received light signal level at the light receiving unit during an infrared light non-emission period. When the second detection result is equal to or greater than a first threshold, it is determined that there is none of a reflecting object, while it is determined that there is the reflecting object when the second detection result is lower than the first threshold, the first detection result is larger than the second detection result, and the first detection result is greater than or equal to a second threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor that detects whether or not an object is in proximity, and an electronic apparatus including the sensor.

  In digital SLR cameras, the angle of view and focus during shooting can be adjusted using an optical eyepiece finder or an LCD (Liquid Crystal Display) provided on the back of the device body or an electronic direct-view monitor, such as an organic EL. They are selected and used together. Some mirrorless cameras and compact digital cameras use an electronic eyepiece finder instead of an optical eyepiece finder, and switch to an electronic direct view monitor according to the shooting environment. .

  These eyepiece type finder and direct view type finder can be switched manually by the user using a changeover switch, and also provided with a function that uses a proximity sensor to detect and automatically switch the user looking into the eyepiece finder. There is.

  In the proximity sensor, the presence or absence of the object is determined by detecting, with the light receiving unit, the infrared light irradiated from the light emitting unit and reflected back to the object. By disposing the proximity sensor in the vicinity of the eyepiece type finder, it is possible to detect that the photographer has brought a face close to the finder.

JP 2013-210314 A

  However, when strong external light is incident on the light receiving unit of the proximity sensor, the light may be mistakenly recognized as reflected light from the object, and it may be erroneously determined that the object is present even though there is no object. is there. As a result, there is a problem that the image display destination is arbitrarily switched to the eyepiece type finder while the subject is being confirmed on the direct view type monitor.

  An object of the present invention is to provide a sensor that is unlikely to malfunction due to external light even when strong external light is incident on a proximity sensor, and an electronic device including the sensor.

In order to achieve the above object, a sensor of the present invention and an electronic apparatus equipped with the sensor include
A light emitting unit that intermittently emits infrared light at predetermined time intervals;
A light-receiving unit that receives infrared light emitted from the light-emitting unit reflected back to the object;
A detection unit for detecting a light reception signal level in the light receiving unit,
The detection unit outputs a light reception signal level at the light receiving unit in an infrared light emission period as a first detection result,
Furthermore, as a second detection result, the light receiving signal level at the light receiving unit in the infrared light non-light emitting period is output,
When the second detection result is equal to or greater than the first threshold, it is determined that there is no reflection object,
When the second detection result is lower than the first threshold, the first detection result is larger than the second detection result, and the first detection result is greater than or equal to the second threshold, the object to be reflected It is characterized by judging that there is an object.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the proximity sensor which is hard to perform external light malfunction, and an electronic device provided with this sensor.

6 is a flowchart showing a series of operations of control processing when the proximity sensor according to Embodiment 1 of the present invention is applied to a digital camera as an example of an electronic device. The block diagram which shows the function structural example which concerns on Embodiment 1 when the proximity sensor of this invention is applied to a digital camera. The figure which shows the relationship between the waveform of each part which concerns on Embodiment 1 of this invention, and a threshold value The flowchart which shows a series of operation | movement of a control process when the proximity sensor which concerns on Embodiment 2 of this invention is applied to a digital camera as an example of an electronic device. The figure which shows the relationship between the waveform of each part and threshold value which concern on Embodiment 2 of this invention. The flowchart which shows a series of operation | movement of a control process when the proximity sensor which concerns on Embodiment 3 of this invention is applied to a digital camera as an example of an electronic device. The figure which shows the relationship between the waveform of each part and threshold value which concern on Embodiment 3 of this invention. 1 is an external view of a digital camera according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. An example in which the present invention is applied to a digital camera will be described below as an example of an electronic device. However, the present invention is not limited to a digital camera, and may include a digital video camera, a smartphone, or the like provided with a proximity sensor.

[First Embodiment]
FIG. 1 is a flowchart illustrating a series of operations of control processing when the proximity sensor according to the first embodiment is applied to a digital camera as an example of an electronic device.

FIG. 2 is a block diagram illustrating a functional configuration example of the digital camera. FIG. 8 is an external view of the digital camera according to the embodiment of the present invention. Note that one or more of the functional blocks shown in FIG. 2 may be realized by hardware such as an ASIC or a programmable logic array (PLA), or by executing software by a programmable processor such as a CPU or MPU. May be. Further, it may be realized by a combination of software and hardware. Therefore, in the following description, even when different functional blocks are described as the operation subject, the same hardware can be realized as the subject.

The imaging optical system 101 includes a lens group including a focus lens and a zoom lens, and a diaphragm. In response to an instruction from the imaging optical system driving unit 108, the zoom lens is moved in the optical axis direction to zoom magnification (or focal length). ) Can be changed. Further, the aperture diameter of the diaphragm can be changed according to an instruction from the imaging optical system driving unit 108. The imaging optical system driving unit 108 includes a driving device that drives the imaging optical system 101 to a predetermined position.

  The image sensor 102 is an image sensor that images a subject image by arranging a photoelectric conversion element on the imaging surface. The image sensor 102 may be an image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The subject optical image formed by the imaging optical system 101 is photoelectrically converted, and further analog / digital converted by an A / D conversion circuit (not shown) to output a digital signal (image data) in units of pixels.

  The imaging system signal processing unit 103 performs image signal processing such as various correction processes on the image data or video data (hereinafter also simply referred to as image data) output from the imaging element 102, and outputs the processed image data. The data is output to the recording / reproduction system signal processing unit 104. The recording / playback signal processing unit 104 encodes the input image data in accordance with, for example, a predetermined encoding method, compresses the amount of information, and converts the data into data suitable for recording. Data processed by the recording / reproducing system signal processing unit 104 is recorded on the recording medium 109. The recording medium 109 is a recording medium such as a memory card for recording the image data output from the recording / reproducing system signal processing unit 104, and includes a semiconductor memory, a magnetic disk, and the like.

  The direct-view display device 105 and the eyepiece display device 106 are image data output from the recording / playback signal processing unit 104, video data for live view display, or an operation screen (menu screen for operating the digital camera 100). ) And the like. The direct view type display device 105 and the eyepiece type display device 106 display images exclusively or simultaneously according to the use state of the digital camera 100. The direct view display device 105 and the eyepiece display device 106 may be any display device such as a liquid crystal display, an organic EL display, and electronic paper.

  The proximity sensor 113 is a sensor including an infrared light emitting unit and a light receiving unit, and is disposed in the vicinity of the eyepiece type display device 106 to irradiate infrared light toward the display direction of the eyepiece type display device 106. The light reception signal detected by the light receiving unit of the proximity sensor 113 is supplied to the detection unit 107. The detection unit 107 outputs a light reception signal level at the light receiving unit during the infrared light emission period as a first detection result, and further receives light at the light reception unit during the infrared light non-light emission period as a second detection result. The signal level is output and supplied to the control unit 110.

  The control unit 110 determines that there is no reflection object when the second detection result is equal to or greater than the first threshold value. In addition, when the second detection result is lower than the first threshold, the first detection result is larger than the second detection result, and the first detection result is greater than or equal to the second threshold. Judge that there is a reflective object. When it is determined that there is a reflection target, the control unit 110 controls to turn off the display of the direct-view display device 105 and turn on the display of the eyepiece display device 106. On the other hand, when it is determined that there is no reflection object, the display of the direct-view display device 105 is turned on and the display of the eyepiece display device 106 is controlled to be turned off.

  The operation switch 111 is a switch for turning on / off the power of the digital camera 100, switching various modes, and the like, and notifies the control unit 110 of the selection result. The detection switch 112 is a switch that detects whether the direct-view display device 105 is in a normal shooting position or a face-to-face shooting position, and notifies the control unit 110 of the detection result.

  The control unit 110 is, for example, a CPU or MPU, and is a control unit that controls the entire digital camera 100 by developing and executing a program stored in the ROM in a RAM work area. The control unit 110 receives signals from the operation switch 111 and the detection switch 112, and controls each unit according to each operation content. Next, the operation flow of this embodiment will be described with reference to FIG. FIG. 1 is a flowchart showing a series of operations of control processing when the proximity sensor according to Embodiment 1 of the present invention is applied to a digital camera as an example of an electronic device. In step S101, the light emitting unit of the proximity sensor 113 starts intermittent light emission of infrared light.

  Next, in step S102, the control unit 110 compares the light reception signal level (second detection result) output from the detection unit 107 in the infrared light non-emission period with the first threshold value. If the second detection result is equal to or greater than the first threshold value, the control unit 110 determines that the external light malfunctions (step S103), turns on the display of the direct-view display device 105 in step S104, and in step S105, the eyepiece. The display of the mold display device 106 is turned off.

  If the second detection result is less than the first threshold value in step S102, then in step S106, the control unit 110 detects the second detection result and the received light signal level (first detection time in the infrared light emission period). Result). When the control unit 110 determines in step S106 that the first detection result is equal to or less than the second detection result, it determines that an external light malfunction has occurred (step S103). When the control unit 110 determines in step S106 that the first detection result is larger than the second detection result, in step S107, the control unit 110 compares the first detection result with a second threshold value.

  When it is determined in step S107 that the first detection result is less than the second threshold, the control unit 110 determines that the eyepiece type display device 106 is unused (step S108), and in step S104. The display of the direct view display device 105 is turned on. When it is determined in step S107 that the first detection result is equal to or greater than the second threshold value, it is determined that the eyepiece display device 106 is used (step S109), and the direct view display device 105 is turned off. (Step 110) The display of the eyepiece type display device 106 is turned on (Step S111).

  FIG. 3 shows the relationship between the waveform of each part and the threshold value in this embodiment. 3A shows the light reception signal level of the light receiving unit of the proximity sensor 113 when there is an object to be reflected and no external light, the first detection result (infrared light emission period) and the second detection result (red) of the detection unit 107. Outside light non-emission period). Since the first detection result is greater than or equal to the second detection result and the first detection result exceeds the second threshold value, it can be determined that there is a reflection object.

  FIG. 3B shows the first detection result and the second detection result of the detection unit 107 when strong external light is incident without blocking the light receiving unit of the proximity sensor 113. Since the second detection result exceeds the first threshold, it can be determined that the malfunction is due to external light. FIG. 3_c is a time when the light reception signal level of the proximity sensor 113 is lower than that in FIG. 3_b. Although the second detection result of the detection unit 107 is lower than the first threshold value, the first detection result is at the same level as the second detection result and is not larger than the second detection result, so it is determined that the external light malfunctions. it can.

  FIG. 3D shows a state in which external light and reflected light from the object are mixed. The second detection result is lower than the first threshold value, and the first detection result is larger than the second detection result. Furthermore, since the first detection result exceeds the second threshold value, it can be determined that there is a reflection object. In FIG. 3D, when the first detection result is lower than the second threshold, the distance between the reflection object and the eyepiece display device 106 is far away, and the eyepiece display device 106 is unused. I can judge.

[Second Embodiment]
FIG. 4 is a flowchart illustrating a series of operations of control processing when the proximity sensor according to the second embodiment is applied to a digital camera as an example of an electronic device. Note that the functional configuration example of the digital camera in the second embodiment is the same as that in the first embodiment, and thus the description thereof is omitted.

  In FIG. 4, the light emitting unit of the proximity sensor 113 starts intermittent infrared light emission in step S101. Next, in step S102, the control unit 110 compares the light reception signal level (second detection result) output from the detection unit 107 in the infrared light non-emission period with the first threshold value. When the second detection result is equal to or greater than the first threshold, the control unit 110 determines that the external light malfunctions (step S103). Next, intermittent infrared light emission of the proximity sensor 113 is stopped in step S201.

  Next, in step S202, the control unit 110 compares the second detection result with the third threshold value, determines that the second detection result is equal to or greater than the third threshold value, and direct view display device in S104. The display of 105 is turned on. Subsequently, in step S105, the display of the eyepiece type display device 106 is turned off. When the control unit 110 determines in step S202 that the second detection result of the detection unit 107 is lower than the third threshold value, the process returns to step S101 and resumes intermittent light emission of infrared light.

  If the second detection result is less than the first threshold value in step S102, then in step S106, the control unit 110 detects the second detection result and the received light signal level (first detection time in the infrared light emission period). Result). When the control unit 110 determines in step S106 that the first detection result is equal to or less than the second detection result, it is determined that the external light malfunctions, and in step S104, the display of the direct-view display device 105 is turned on. . When the control unit 110 determines in step S106 that the first detection result is larger than the second detection result, in step S107, the control unit 110 compares the first detection result with a second threshold value.

  When it is determined in step S107 that the first detection result is less than the second threshold, the control unit 110 determines that the eyepiece type display device 106 is unused (step S108), and in step S104. The display of the direct view display device 105 is turned on. When it is determined in step S107 that the first detection result is equal to or greater than the second threshold value, it is determined that the eyepiece display device 106 is used (step S109), and the direct view display device 105 is turned off. (Step 110) The display of the eyepiece type display device 106 is turned on (Step S111).

  FIG. 5 shows the relationship between the waveform of each part and the threshold value in this embodiment. FIG. 5A shows the first detection result and the second detection result of the detection unit 107 when strong external light is incident without blocking the light receiving unit of the proximity sensor 113. Since the second detection result exceeds the first threshold value, it is determined that the malfunction is caused by outside light, and intermittent light emission of infrared light from the proximity sensor 113 is stopped.

  FIG. 5B is a time when the light reception signal level of the proximity sensor 113 is lower than that in FIG. This is the case where the user begins to block the external light by approaching his face to look into the eyepiece display device 106. Here, since the second detection result of the detection unit 107 falls below the third threshold value, the intermittent light emission of the infrared light of the proximity sensor 113 is resumed. FIG. 5C shows a state where ambient light and reflected light from the object are mixed. The second detection result is lower than the first threshold value, and the first detection result is larger than the second detection result. Furthermore, since the first detection result exceeds the second threshold value, it can be determined that there is a reflection object.

  In FIG. 5C, when the first detection result is lower than the second threshold value, the distance between the reflective object and the eyepiece display device 106 is long, and the eyepiece display device 106 is unused. I can judge.

  According to the present embodiment, wasteful power consumption can be suppressed by stopping infrared light emission while the proximity sensor 113 detects strong external light.

[Third Embodiment]
FIG. 6 is a flowchart showing a series of operations of control processing when the proximity sensor according to the third embodiment is applied to a digital camera as an example of an electronic device. Note that the functional configuration example of the digital camera in the third embodiment is the same as that in the first embodiment, and a description thereof will be omitted.

  In FIG. 6, in step S <b> 301, the light emitting unit of the proximity sensor 113 starts intermittent light emission of infrared light having a constant duty ratio. In step S302, control unit 110 calculates an average value of the light reception levels output from detection unit 107 within a time that is an integral multiple of the light emission cycle. Next, in step S303, the control unit 110 compares the level of each received light signal with the obtained average value, and obtains the ratio of the number of samples exceeding the average value and the number of samples below the average value. Furthermore, the appearance pattern of whether the sample exceeding the average value and the sample falling below are generated randomly or periodically is confirmed.

  Next, in step S304, the control unit 110 determines whether the ratio of the obtained number of samples and the appearance pattern are equal to the emission duty ratio of the infrared light emitted from the light emitting unit of the proximity sensor 113. When it is determined that they are equal, it is determined in step S305 whether the obtained average value is equal to or greater than a fourth threshold value. If it is determined that the value is greater than or equal to the fourth threshold value, it is determined that the eyepiece type display device 106 is used (step S306), and the direct view display device 105 is turned off in step S307. In step S308, the display of the eyepiece type display device 106 is turned on.

  If it is determined in step S304 that the infrared light emission duty is not equal to the ratio of the number of samples above the average value to the number of samples below the average value, there is no reflective object and the eyepiece display device It is determined that 106 is not used (step S309). Next, in step S310, the display of the direct-view display device 105 is turned on, and in step S311, the display of the eyepiece display device 106 is turned off.

  FIG. 7 shows the relationship between the waveform of each part and the threshold value in this embodiment. In FIG. 7A, it can be determined that there is no reflected light from the object because samples above and below the average value of the received light signal level are randomly generated.

  7_b and FIG. 7_c are periodic in which the ratio of the number of samples above and below the average value is equal to the light emission duty of the light emitting unit of the proximity sensor 113, and the sample above and below the average value is equal to the light emission duty of the light emitting unit. Has occurred. Furthermore, since the average value is greater than or equal to the fourth threshold, it can be determined that there is a reflection object.

  FIG. 7_d shows that the ratio of the number of samples above and below the average value is equal to the light emission duty of the light emitting unit of the proximity sensor 113, and the samples above and below the average value are periodically generated equal to the light emission duty of the light emitting unit. ing. However, since the average value is less than the fourth threshold value, the distance between the reflective object and the eyepiece display device 106 is far away, and it can be determined that the eyepiece display device 106 is unused.

  According to this embodiment, if the light emission duty of the light emitting unit of the proximity sensor 113 is known, it is not necessary to synchronize the light emission timing of the infrared light and the light reception signal level detection timing.

  In the present embodiment, when the average value of the received light level output from the detection unit 107 is larger than a predetermined value, the intermittent light emission of the light emitting unit of the proximity sensor 113 is stopped in the same manner as in the second embodiment, thereby reducing unnecessary power. Consumption can be suppressed.

100 Digital Camera 107 Detection Unit 110 Control Unit 113 Proximity Sensor

Claims (5)

A light emitting unit that intermittently emits infrared light at predetermined time intervals;
A light-receiving unit that receives infrared light emitted from the light-emitting unit reflected back to the object;
A detection unit that outputs a light reception signal level at the light reception unit,
The detection unit outputs a light reception signal level at the light receiving unit in an infrared light emission period as a first detection result,
Furthermore, as a second detection result, the light receiving signal level at the light receiving unit in the infrared light non-light emitting period is output,
When the second detection result is equal to or greater than the first threshold, it is determined that there is no reflection object,
When the second detection result is lower than the first threshold, the first detection result is larger than the second detection result, and the first detection result is greater than or equal to the second threshold, the object to be reflected A sensor that determines that there is an object, or an electronic device including the sensor. When the second detection result is equal to or greater than the first threshold, intermittent infrared light emission is stopped, and infrared light is detected when the second detection result is detected to be less than the third threshold. The sensor according to claim 1, or an electronic device including the sensor, wherein the intermittent light emission is resumed. 3. The sensor according to claim 2, or an electronic device including the sensor, wherein the third threshold is lower than the first threshold and higher than the second threshold. A light emitting unit that intermittently emits infrared light at regular time intervals;
A light-receiving unit that receives infrared light emitted from the light-emitting unit reflected back to the object;
A detection unit that outputs a light reception signal level at the light reception unit;
An arithmetic operation for calculating an average value of detection results of the detection unit within a period that is an integral multiple of the light emission cycle of the infrared light, and a ratio of samples in which the received light signal level is larger than the average value and the samples smaller than the average value And
And an identification unit for identifying an appearance pattern of whether a sample above the average value and a sample below the sample are randomly generated or periodically generated,
A sensor that determines that there is an object to be reflected when the result of calculation and identification is equal to the ratio of emission of infrared light that emits intermittent light and the non-light emission period, and an electronic device using the sensor. When the average value detected by the detection unit is equal to or greater than a fourth threshold, the intermittent emission of infrared light is stopped, and the average value is less than a fifth threshold that is lower than the fourth threshold. 5. The sensor according to claim 4, or an electronic device including the sensor, wherein intermittent light emission of infrared light is resumed when detected.