JP5283516B2 - Optical device, object detection method using the optical device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device detecting approach of a detection target, and also to provide a method of detecting objects and electronic equipment using the optical device. <P>SOLUTION: The optical device is provided with: an infrared LED; a CMOS image sensor for outputting a signal indicating the quantity of light and spot position of reflection light; a signal processing section 20 for amplifying outputted signals and executing signal processing; and a database storage section 30 for storing a relationship between the distance of a detection object and the quantity of reception light for each reflection factor and data indicating first and second reference values. The signal processing section 20 executes: first signal processing for calculating the distance of the detection object based on the spot position; second signal processing for obtaining the reflection factor of the detection object by comparing the distance of the detection object and the quantity of light of the reflection light with the relationship between the distance of the detection object and the quantity of reception light for each reflection factor; third signal processing for determining whether the reflection factor matches with the first reference value; fourth signal processing for determining whether the distance of the detection object matches with a second reference value when the reflection factor matches with the first reference value; and fifth signal processing for outputting a signal indicating approach of the detection target when the reflection factor matches with the first reference value. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an optical device that detects the presence or absence of an object to be detected, an object detection method using the optical device, and an electronic apparatus.

  In recent years, a screen with a touch panel function has been adopted as a display screen of a mobile phone, and this screen with a touch panel function is used as a substitute for a mechanical key (a key having a mechanical structure). By adopting this screen with a touch panel function, it is possible to carry out input operations to mobile phones without operating mechanical keys. Therefore, the operability in the human interface for input and the design of the mobile phone are improved.

  However, when a person's skin touches the screen with a touch panel function during a call, this contact is detected and the mobile phone malfunctions. In order to solve such a problem, there is a need for a proximity detection sensor that detects whether or not what is in contact with the screen with a touch panel function is human skin (particularly cheek).

  An example of such a proximity detection sensor is an optical sensor, and an example of this optical sensor is a reflective photointerrupter disclosed in Japanese Patent Application Laid-Open No. 8-130325, which is Patent Document 1. . As another example, there is an object detection sensor disclosed in Japanese Patent Application Laid-Open No. 2005-249534, which is Patent Document 2.

  In the reflection type photo interrupter disclosed in Japanese Patent Application Laid-Open No. 8-130325, a light shielding resin case is provided with a first concave portion, a second concave portion and a third concave portion, and the first concave portion and the second concave portion are provided. The light receiving element or the light emitting element mounted on the header lead is disposed, and a resistor in an erected state is disposed between the two leads in the third recess. Furthermore, in such an arrangement state, the first concave portion, the second concave portion, and the third concave portion are molded with a translucent resin body.

  On the other hand, the object detection sensor disclosed in Japanese Patent Application Laid-Open No. 2005-249534 irradiates infrared light from a transmission unit to a reception unit and receives the infrared light when the infrared remote control receiving element of the reception unit receives the infrared light. The infrared light is photoelectrically converted into an electrical signal, and the determination unit confirms whether the infrared light irradiated from the transmission unit is blocked based on the state of the electrical signal, and the presence or absence of an object is determined according to the confirmation result. It is the structure of judging.

JP-A-8-130325 JP-A-2005-249534

  In general, when detecting an object in contact with a screen in a mobile phone, it is necessary to detect a person's skin and a substance having a reflectance different from that of a person's skin.

  However, in the reflection type photointerrupter described above, the light irradiated from the light emitting element and reflected by the object (hereinafter also simply referred to as “reflected light”) is captured by the light receiving element, and the total amount of the reflected light thus captured is captured. The presence or absence of a detection object (for example, human skin) is determined based on whether or not the amount of received light exceeds a threshold value. When such a discrimination method is used, if the detected object has a low reflectivity such as hair, the detected object distance becomes extremely short and cannot be detected appropriately. On the other hand, if the detected object has a high reflectivity such as a mirror or a blank sheet, the detected object distance is extended, so that the detected object is erroneously detected even when the object is not close.

  Therefore, when the reflection type photo interrupter is used as a proximity detection sensor in a mobile phone, there is a problem in that detection cannot be performed correctly because the detected object distance varies depending on the reflectance.

  On the other hand, according to the above-described object detection sensor, the transmitter and the receiver need to be arranged to face each other while maintaining a separation distance that allows an object to pass therethrough, so that the sensor is used as a proximity detection sensor in a mobile phone. There was a problem that it was difficult.

  The present invention was devised to solve such problems, and its purpose is to determine whether or not the detection object is a detection object by considering the reflectance of the detection object, and to detect the detection object. It is an object of the present invention to provide an optical device that can detect that a detection target is close by determining whether or not the object is close, and an object detection method and electronic apparatus using the optical device.

In order to solve the above-described problem, the optical device of the present invention is configured to prevent the malfunction of the mobile communication terminal caused by the proximity or contact of the object with the input / output screen of the mobile communication terminal in communication. An optical device that detects an object to be detected, a light emitting element that emits infrared light, and light reflected from the detected object by the infrared light, and outputs a signal indicating the light quantity and incident position of the reflected light And a signal processing unit that amplifies the signal output from the light receiving device and performs signal processing, and the detected object distance and the amount of received light for each reflectance stored in the database storage unit Signal processing using data indicating the relationship between the first reference value and the data indicating the first reference value which is the reflectance of the detection target, and data indicating the second reference value which is the distance determined to be close to each other. Fruit The signal processing unit detects the detected object distance based on the incident position (step S3 to be described later), and detects the calculated detected object distance and the amount of reflected light for each reflectance. Second signal processing (step S4 to be described later) for obtaining the reflectance of the detected object in comparison with data indicating the relationship between the object distance and the amount of received light, and whether or not the obtained reflectance matches the first reference value. Third signal processing (to be described later in step S5) and fourth signal processing (to be described later) for determining whether or not the calculated detected object distance matches the second reference value when the first reference value matches. Step S6) and the fifth signal processing (step S7 described later) for outputting a signal indicating that the detection target is close when the second reference value is matched.

  Thereby, it is possible to determine whether or not the detected object is a detection target based on the obtained reflectance of the detected object. Furthermore, when the detected object is the detection target, Can be detected. Thereby, it is possible to prevent erroneous detection such that an object with low reflectance is not properly detected or an object with high reflectance is erroneously detected.

  In the optical device of the present invention, the light emitting element is an infrared LED, the light receiving element is a CMOS image sensor, the infrared LED and the CMOS image sensor are mounted on the same substrate, and sealed by a resin mold part. The infrared LED and the CMOS image sensor may be blocked by a light blocking portion.

  With such a configuration, a small and inexpensive optical device can be manufactured.

  In addition, when an optical device in which the wavelength of the infrared light is set to 940 nm, the first reference value is 0.1 or less and 0.2 to 0.4, and the second reference value is set to 50 mm or less is mounted on a mobile phone It is possible to more accurately detect whether human skin (reflectance 0.2 to 0.4) or hair (reflectance 0.1 or less) is within 50 mm from the mobile phone (light emitting unit).

In the object detection method of the present invention, the object is detected as an object to be detected in order to prevent malfunction of the mobile communication terminal caused by the proximity or contact of the object with the input / output screen of the mobile communication terminal in communication. An object detection method using an optical device, which receives a light emitting element that emits infrared light and reflected light from an object detected by the infrared light, and outputs a signal indicating the light quantity and incident position of the reflected light. A light receiving element, a signal processing unit that amplifies a signal output from the light receiving element and performs signal processing, data indicating a relationship between a detected object distance and a received light amount for each reflectance, and reflection of a detection target This is implemented using an optical device that includes a database storage unit that stores data indicating a first reference value that is a rate and data indicating a second reference value that is a distance determined to be close. Is shall. Further, the signal processing performed by the signal processing unit includes first signal processing for calculating a detected object distance based on the incident position, and the calculated detected object distance and the amount of reflected light for each reflectance. Second signal processing for determining the reflectance of the detected object in comparison with data indicating the relationship between the detected object distance and the amount of received light, and third for determining whether or not the determined reflectance matches the first reference value. If the signal processing matches the first reference value, the fourth signal processing for determining whether the calculated detected object distance matches the second reference value, and the detection target if the second reference value matches And fifth signal processing for outputting a signal indicating that the object is close.

  Thereby, it can be determined whether or not the detected object is a detection target based on the obtained reflectance of the detected object. Further, when the detected object is the detection target, it is determined that the detection target is close. It can be detected. Thereby, it is possible to prevent erroneous detection such that an object with low reflectance is not properly detected or an object with high reflectance is erroneously detected.

  The electronic apparatus of the present invention is one in which any one of the optical devices described above is mounted.

  Thereby, malfunction of an electronic device can be prevented.

  Since the present invention is configured as described above, it is possible to accurately detect the proximity of an object set in advance as a detection target with a simple configuration.

It is explanatory drawing which shows one Embodiment of the optical device of this invention. It is sectional drawing which shows a specific example of the proximity sensor which comprises the optical device shown in FIG. It is explanatory drawing which shows roughly the position of the light emission part of an infrared LED, the position of a reflective site | part, and a spot position. It is a graph which shows the relationship between the spot position and detected object distance in the proximity sensor shown in FIG. It is a graph which shows the specific examples 1-3 of the relationship between the measurement position and power density in the proximity sensor shown in FIG. It is a flowchart which shows one Embodiment of the object detection method of this invention. It is explanatory drawing which shows the mobile telephone which is one Embodiment of the electronic device of this invention. It is sectional drawing which shows an example of the conventional proximity sensor. It is a graph which shows the relationship between the distance (detected object distance) from the light emission part of a light emitting element to a detected object, and received light quantity.

  Hereinafter, an optical device according to an embodiment of the present invention, an object detection method using the optical device, and an electronic apparatus will be described.

[Conventional proximity sensor]
First, a conventional proximity sensor constituting a general optical device will be described for comparison with the optical device of the present invention.

  FIG. 8 is a cross-sectional view showing an example of a conventional proximity sensor.

  In FIG. 8, two detection objects 111 and 112 are shown together with the proximity sensor, and the detection object 111 is located closer to the proximity sensor than the detection object 112.

  The proximity sensor shown in FIG. 8 includes a light emitting diode (hereinafter simply referred to as “infrared LED”) 102 for emitting infrared light and a light receiving element 103 capable of detecting infrared light on the upper surface of the substrate 101. The light shielding portion 104 is disposed between the infrared LED 102 and the light receiving element 103. Then, the surfaces of the infrared LED 102 and the light receiving element 103 excluding the light shielding portion 104 are respectively covered with the mold portion 105.

  Further, convex lens-shaped lens portions 105 a and 105 b are respectively formed at positions on the upper surface of the mold portion 105 facing the light emitting portion of the infrared LED 102 and the light receiving surface of the light receiving element 103.

  In such a configuration, when the infrared light (light pulse P110) emitted from the infrared LED 102 is located at a position facing the upper surface of the substrate 101, the surface of the object (for example, the detection object 111 or the detection object 112). The reflected light from the object surface (light pulse P111 or light pulse P112) enters the light receiving element 103.

  The light receiving element 103 described here is a light receiving element having a configuration capable of simply measuring the amount of light received on the entire light receiving surface (for example, a light receiving element that outputs an electric signal obtained by photoelectrically converting the received reflected light). . Although not shown, the light receiving element 103 amplifies the electric signal, and determines whether or not there is a detection object according to whether or not the electric signal after the amplification exceeds a preset threshold value. A signal processing circuit may be provided, or the signal processing circuit may be electrically connected.

  In general, the light power (light quantity) of the reflected light incident on the light receiving element 103 is determined by the reflectance of the detected object and the light emitting unit when the light power (light quantity) of the infrared light output from the light emitting element 102 is constant. Depends on the distance to the detected object.

  FIG. 9 is a graph showing the relationship between the distance from the light emitting part of the light emitting element to the detected object (detected object distance) and the amount of received light, and the horizontal axis represents the distance from the light emitting part of the light emitting element 102 to the reflection part of the detected object. The vertical axis represents the received light amount (au) of the reflected light incident on the light receiving surface of the light receiving element.

  FIG. 9 shows the detected object distance when an object with a reflectance of 0.9 is detected, when an object with a reflectance of 0.3 is detected, and when an object with a reflectance of 0.055 is detected. And three graphs showing the relationship between the received light amount and the received light amount. In the figure, when a solid line L10 detects an object with reflectivity (r) = 0.9, a dashed-dotted line L20 indicates an object with reflectivity (r) = 0.3, and a broken line L30 indicates a reflectivity (r). The relationship when an object of = 0.055 is detected is shown. Further, the threshold value of the amount of received light when determining the presence or absence of the detected object is P0.

  As shown in FIG. 9, the amount of received light has a peak (focal point) at a certain detected object distance, and decreases past the peak in proportion to the square of the distance. Which distance the focus is on depends on the optical system of each proximity sensor (for example, the characteristics and arrangement of each element and the shape and arrangement of the lens part). In general, the longer the distance (separation distance) from the light emitting element 102 to the light receiving element 103, the longer the proximity sensor.

<One Embodiment of Optical Device of the Present Invention>
Next, an optical device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory view showing an embodiment of the optical device of the present invention. FIG. 1 also shows the detected object and the light pulse together with the optical device.

  The main function of the optical device of the present embodiment is to determine whether or not the detected object is within the detected object distance, but this optical device uses the position of the spot formed by the reflected light from the detected object (so-called "Incident position", hereinafter also referred to simply as "spot position") and whether the detected object is an object (detected object) preset as a detected object by measuring the reflectance of the detected object And a function of determining whether or not the detected object exists within a preset detected object distance.

  Note that the spot of reflected light is formed not in a point but in a region having a light receiving surface. Therefore, in this embodiment, the position of the center of gravity of the spot is set as the spot position.

  As shown in FIG. 1, the optical device according to the present embodiment emits a light pulse P10, receives a light pulse P11 that is reflected light reflected by the surface of the detection object 11, and relates to a spot formed by the received light pulse P11. The proximity sensor 10 that outputs a signal indicating data, the signal output from the proximity sensor 10 is amplified and signal processing is performed, and whether or not the detection object 11 is a detection object is detected in advance. A signal processing unit 20 that determines whether or not the detected object distance exists within a set distance, and a database storage unit that stores in advance data used for signal processing and various determinations in the signal processing unit 20 30.

  The signal processing unit 20 and the database storage unit 30 may have, for example, an IC (Integrated Circuit) chip or a circuit configuration assembled with a discrete.

  As will be described in detail later, the signal processing performed by the signal processing unit of the present invention includes first signal processing for calculating the detected object distance based on the incident position, the calculated detected object distance, and the reflected light. The second signal processing for obtaining the reflectance of the detected object by comparing the amount of light with the data indicating the relationship between the detected object distance and the amount of received light for each reflectance, and the obtained reflectance matches the first reference value Third signal processing for determining whether or not to perform, fourth signal processing for determining whether or not the calculated detected object distance matches the second reference value when the first reference value matches, a second signal processing; When the reference value matches, the fifth signal processing is performed to output a signal indicating that the detection target is close.

  FIG. 1 shows an optical device including a database storage unit 30 as an embodiment. However, the optical device of the present invention is not limited to this mode. For example, the database storage unit is external to the optical device. The signal processing unit 20 may perform signal processing and various determinations using the data transmitted from the database storage unit.

  Here, a specific example of the proximity sensor 10 will be described.

  FIG. 2 is a cross-sectional view showing a specific example of the proximity sensor constituting the optical device shown in FIG.

  The proximity sensor 10 includes an infrared LED 2 as a light emitting element that emits infrared light (light pulse P10) and a CMOS (Complementary Metal Oxide Semiconductor) image as a light receiving element on the same surface of the substrate 1 (upper surface in FIG. 2). The sensors 3 are mounted, and a light-shielding portion 4 is disposed between the infrared LEDs 2 and the CMOS image sensor 3. Further, the infrared LED 2 and the CMOS image sensor 3 except for the light shielding part 4 are covered with the mold part 5.

  As the substrate 1, for example, a substrate based on glass epoxy or BT resin (a registered trademark of a thermosetting resin manufactured by Mitsubishi Gas Chemical Company, Inc., a thermosetting resin made of a maleimide triazine resin, etc.) is used. it can.

  As the CMOS image sensor 3, one capable of detecting (imaging) infrared light is used. Although not shown, when there is no object ahead in the emission direction of the light pulse P10, there is no reflected light, that is, there is no output from the CMOS image sensor 3.

  In this specification, the amount of light received by each pixel (not shown) of the CMOS image sensor 3 is referred to as “power density”, and the amount of light received on the entire light receiving surface of the CMOS image sensor 3 is referred to as “light reception amount”.

  The light receiving element constituting the conventional proximity sensor simply outputs a signal indicating the amount of light received by the entire light receiving surface. On the other hand, the CMOS image sensor 3 used as the light receiving element in the present embodiment outputs a signal indicating the power density for each pixel. Therefore, the signal processing unit 20 can detect the spot formed by the reflected light incident on the light receiving surface based on the signal output from the CMOS image sensor 3 and calculate the center of gravity of the spot to obtain the spot position. . Further, the signal processing unit 20 integrates the power density of all the pixels based on the signal output from the CMOS image sensor 3, and thereby the entire surface of the light receiving surface that is the amount of reflected light incident on the light receiving surface of the CMOS image sensor 3. Can be calculated.

  Since the light shielding part 4 is a member for preventing light pulses from directly entering the light receiving surface of the CMOS image sensor 3 from the light emitting part of the infrared LED 2, for example, PPS (polyphenylene sulfide) resin or filler is added. It is formed using a material that does not transmit infrared light, such as an epoxy resin.

  Convex lens-shaped lens portions 5 a and 5 b are formed at positions facing the light emitting portion of the infrared LED 2 and the light receiving surface of the CMOS image sensor 3 on the surface of the mold portion 5. The mold part 5 may be a resin mold part formed using a material that transmits infrared light, such as an epoxy resin.

  In FIG. 1, together with the proximity sensor 10, the light pulse P10 emitted from the infrared LED 2, the two detection objects 11a and 11b, and the reflection reflected on the surface of one of these detection objects 11a and 11b. Light pulses P11a and P11b, which are light, are illustrated. Further, it is assumed that the detected object 11a is closer to the proximity sensor 10 than the detected object 11b. Further, here, the two detection objects 11a and 11b and the light pulses P11a and P11b are shown simultaneously in one figure. However, in actuality, either one of the detection objects is present and the detection object is detected. Only one of the detected objects (for example, the detected object 11a located closest to the proximity sensor 10) is detected.

  As shown in FIG. 2, the light pulse P10 emitted from the infrared LED 2 is reflected by the detection object 11a or the detection object 11b when the detection object 11a or the detection object 11b is in front of the emission direction of the light pulse P10. Then, the light pulse P11a or the light pulse P11b, which is reflected light from the detection object 11a or the detection object 11b, enters the CMOS image sensor 3 and forms a spot on the CMOS image sensor 3.

  Note that an arrow B1 shown in FIG. 2 indicates a direction parallel to a straight line connecting the center of gravity of the light emitting portion of the infrared LED 2 and the center of gravity of the light receiving surface of the CMOS image sensor 3. This is called the axial direction. Further, in this X axis, the direction from the infrared LED 2 to the CMOS image sensor 3 is the + direction, and the direction from the CMOS image sensor 3 to the infrared LED 2 is the − direction, and the center of gravity of the light receiving surface of the CMOS image sensor 3 is “0”.

[Calculation of detected object distance]
Next, the procedure for calculating the detected object distance, which is the distance from the light emitting part of the infrared LED to the detected object, will be described.

  The distance from the light emitting part of the infrared LED 2 constituting the proximity sensor 10 to the reflection part of the detection objects 11a and 11b is a spot obtained from the signal output from the CMOS image sensor 3 in the signal processing part 20 shown in FIG. Calculated according to the principle of triangulation based on the position.

  FIG. 3 is an explanatory diagram schematically showing the position of the light emitting portion of the infrared LED, the position where the light pulse is reflected on the detected object (the position of the reflection part), and the spot position.

  In the figure, a black circle A1 indicates the position of the light emitting portion of the infrared LED, a black circle A2 indicates the position of the reflection portion, and a black circle A3 indicates the spot position.

  Further, there are a straight line connecting the light emitting part (black circle A1) of the infrared LED to the spot position (black circle A3) and a straight line connecting the light emitting part (black circle A1) of the infrared LED to the position of the reflection part (black circle A2). The straight line connecting the light emitting part (black circle A1) of the infrared LED to the spot position (black circle A3) and the straight line connecting the position of the reflection site (black circle A2) to the spot position (black circle A3), where θ1 is the angle formed. The formed angle is θ2, the distance from the light emitting part (black circle A1) of the infrared LED to the position of the reflection part (black circle A2) is Ldistance, and the light emitting part (black circle A1) of the infrared LED to the spot position (black circle A3). Is a distance L0.

  At this time, the distance Ldistance can be expressed by the following equation (1) according to the principle of triangulation. In Equation (1), Π = 180 °.

Ldistance = L0 × sin (θ2) / sin (Π− (θ1 + θ2)) (1)
In equation (1), “θ1” is a value determined by the design on the light emitting side that constitutes the optical system of the proximity sensor 10, and “θ2” is a value determined by the design on the light receiving side that constitutes the optical system of the proximity sensor 10. Yes, “L0” is a value calculated based on the spot position.

  In other words, the detected object distance, which is the distance (distance L distance) from the light emitting part of the infrared LED 2 to the reflection part of the detected objects 11a and 11b, is a value that can be calculated based on the spot position detected by the CMOS image sensor 3.

  FIG. 4 is a graph showing the relationship between the spot position and the detected object distance in the proximity sensor shown in FIG. 2, the vertical axis shows the spot position (mm), and the horizontal axis shows the detected object distance (mm). . In the figure, the spot position is represented by the distance in the X-axis direction (that is, the value of the X-axis) from the center of gravity of the light receiving surface of the CMOS image sensor to the center of gravity of the spot.

  Moreover, the output example shown in FIG. 4 is an example, and the curve differs depending on the design of the optical system of the proximity sensor.

  In this output example, as shown in FIG. 4, when the detected object is close to the proximity sensor and the detected object distance is small, the reflected light forms a spot at a place where the value of the X axis is large, so the spot position in the X axis direction The value of increases. Conversely, when the detected object is far from the proximity sensor and the detected object distance is large, the reflected light forms a spot in a place where the value of the X axis is small, so the value of the spot position in the X axis direction becomes small.

  Here, a specific example of the power density of spots formed on the CMOS image sensor 3 will be described with reference to the drawings.

  FIG. 5 is a graph showing specific examples 1 to 3 of the relationship between the measurement position and the power density in the proximity sensor shown in FIG. 2, the horizontal axis indicates the measurement position (mm), and the vertical axis indicates the power at each measurement position. Density (lux) is shown. In the figure, the measurement position is represented by the distance in the X-axis direction from the center of gravity of the light receiving surface of the CMOS image sensor (that is, the value of the X-axis).

  As described above, the detected object distance is a value calculated by the signal processing unit 20 using the value of the spot position. For example, in the specific example 1 shown in FIG. 5A, the spot position is 0.44 mm. When the detected object distance is calculated according to the principle of triangulation using the value of the spot position, the detected object distance (d) = 1 mm is obtained. Similarly, in the specific example 2 shown in FIG. 5B where the spot position is 0.14 mm, the detected object distance (d) = 5 mm is obtained, and the specific example shown in FIG. 5C where the spot position is 0.013 mm. In Example 3, the detected object distance (d) = 50 mm is obtained.

  Instead of calculating the detected object distance in accordance with the principle of triangulation, data indicating the relationship between the spot position and the detected object distance as shown in FIG. 4 is created in advance, and the data is stored in the database storage unit 30. It may be stored in advance, and the signal processing unit 20 may obtain the detected object distance from the value of the spot position based on this data.

[Calculation of received light amount]
Next, a procedure for calculating the amount of reflected light incident on the light receiving surface of the CMOS image sensor will be described.

  As described above, the received light amount of the reflected light incident on the light receiving surface of the CMOS image sensor 3 is integrated in the signal processing unit 20 along the X axis with respect to the X axis value (see FIG. 5). , The power density of all the pixels constituting the light receiving surface of the CMOS image sensor 3 is integrated).

  The database storage unit 30 stores in advance data indicating the relationship between the detected object distance and the amount of received light for each reflectance, which is the same data as the data shown in FIG. The reflectance of the detected object detected by the proximity sensor 10 is obtained by comparing the calculated detected object distance and the received light amount with the data indicating the relationship between the detected object distance and the received light amount for each reflectance. Required in part 20. Specifically, each calculated value of the detected object distance and the amount of received light is applied to a graph showing the relationship between the detected object distance and the amount of received light, and a curve that overlaps the intersection of the calculated detected object distance and the received light amount (for example, In FIG. 9, a curve including any one of the solid line L10, the one-dot chain line L20, and the broken line L30) or a curve closest to the intersection is selected, and the reflectance indicated by the selected curve is the reflectance of the detected object. And

  Note that FIG. 9 shows the relationship between the detected object distance and the amount of received light for each of the detected objects having reflectance (r) = 0.9, 0.3, and 0.055, but this is merely an example. The data stored in the database storage unit 30 is changed according to the setting of the detection object.

[Judgment regarding presence and proximity of detection object]
Next, a procedure for determining whether or not the detection object is close will be described.

  The signal processing unit 20 determines whether or not the reflectance obtained by the above-described procedure matches the first reference value (a numerical value or a numerical range indicating the reflectance of the detection target). Further, it is further determined whether or not the detected object distance calculated by the above-described procedure matches the second reference value (a numerical value or a numerical value range indicating a distance determined to be close). Note that data indicating the first reference value and the second reference value used in these determinations is stored in the database storage unit 30 in advance.

例えば、表１に示すように、赤外ＬＥＤから出力される光パルスの波長（λ）＝９４０ｎｍの場合、人の肌の反射率は０．２〜０．４であり、人の髪の毛の反射率は０．１未満である。従って、検出対象物が人の肌と髪の毛であった場合、信号処理部２０は、算出された反射率が０．２〜０．４または０．１未満であれば検出物が検出対象物である（人の肌または髪の毛である）と判断する。一方、算出された反射率が０．２〜０．４または０．１未満に一致しない場合は検出物が検出対象物ではないと判断する。

For example, as shown in Table 1, when the wavelength (λ) of the light pulse output from the infrared LED is 940 nm, the reflectance of the human skin is 0.2 to 0.4, and the reflection of the human hair The rate is less than 0.1. Therefore, when the detection target is human skin and hair, the signal processing unit 20 determines that the detection target is the detection target if the calculated reflectance is 0.2 to 0.4 or less than 0.1. Judged to be present (human skin or hair). On the other hand, when the calculated reflectance does not match 0.2 to 0.4 or less than 0.1, it is determined that the detected object is not the detection object.

  According to the optical device of the present embodiment, since such a configuration is provided, the proximity of the detection target can be detected.

<One Embodiment of Object Detection Method of the Present Invention>
Next, an embodiment of the object detection method of the present invention will be described with reference to the drawings.

  FIG. 6 is a flowchart showing an embodiment of the object detection method of the present invention.

  According to the object detection method of the present embodiment, first, the light pulse P10 is emitted from the light emitting portion of the infrared LED 2 (step S1). The emission of the light pulse P10 may be performed intermittently or continuously.

  After the emission of the light pulse P10, when the CMOS image sensor 3 receives the light pulse P11 which is reflected light (when the determination result in step S2 is “YES”), the proximity sensor 10 to the signal processing unit 20 A signal indicating data relating to the spot formed by the light pulse P11 is output. When the CMOS image sensor does not receive the reflected light (when the determination result in step S2 is “NO”), no signal is output from the proximity sensor 10, so the signal processing unit 20 determines that there is no detection object. Then, the process ends.

  Subsequently, the signal processing unit 20 calculates the center of gravity of the spot based on the signal output from the proximity sensor 10 (more specifically, the CMOS image sensor 3) to obtain the spot position, and triangulation is performed from the obtained spot position. The detected object distance is calculated according to the principle, and the received light amount of the spot is calculated (step S3). Instead of calculating the detected object distance according to the principle of triangulation, data indicating the relationship between the spot position and the detected object distance (see FIG. 4) is stored in advance in the database storage unit 30, and based on the data. The detected object distance may be obtained from the spot position.

  Next, the signal processing unit 20 compares the detected object distance and the received light amount obtained in step S3 with the relationship between the detected object distance and the received light amount for each reflectance indicated by the data stored in the database storage unit 30 in advance. Thus, the reflectance of the detected object is obtained (step S4).

  Further, in the signal processing unit 20, based on the data indicating the first reference value (reflectance of the detection target) stored in advance in the database storage unit 30, the reflectance obtained in step S4 is the reflectance of the detection target. (Step S5).

  If it does not coincide with the reflectance of the detection target (when the determination result in step S5 is “NO”), the process ends. On the other hand, if they match (when the determination result in step S5 is “YES”), the signal processing unit 20 determines that the second reference value stored in advance in the database storage unit 30 (is approaching). On the basis of the data indicating the distance to be detected) and the detected object distance obtained in step S3, it is determined whether or not the detected object is close (step S6).

  If it is not close (if the determination result in step S6 is “NO”), the process ends. In the case where they are close (when the determination result in step S6 is “YES”), a signal indicating that the detection target is close is output from the optical device (step S7), and then processing is performed. Ends.

  According to the object detection method of the present embodiment, since such a configuration is provided, the proximity of the detection target can be detected.

<One Embodiment of Electronic Device of the Present Invention>
Next, an embodiment of an electronic apparatus according to the present invention will be described with reference to the drawings.

  Here, a mobile phone equipped with the optical device shown in FIG. 1 will be described as an embodiment of the electronic apparatus. Note that this mobile phone is the above-mentioned touch-panel model.

  FIG. 7 is an explanatory view showing a mobile phone which is an embodiment of the electronic apparatus of the present invention.

  The mobile phone 41 includes a screen 41a with a touch panel function, and includes a detection window 41b in the vicinity of the screen 41a with a touch panel function. Furthermore, the mobile phone 41 has a built-in optical device, and the optical device is disposed at a position facing the detection window 41b.

  In such a mobile phone 41, since it is necessary to determine the presence or absence of human skin or hair near the screen 41a with a touch panel function using an optical device during a call, the detection target is the skin of the human 42 (especially cheeks). ) And hair. Therefore, in the database storage unit 30, “r = 0.2 to 0.4 and r <0.1 (see Table 1)” are stored in advance as the first reference value (reflectance of the detection target). .

  Furthermore, the distance at which the detected object is determined to be close is preferably, for example, 50 mm or less. Therefore, “50 mm or less” is stored in advance in the database storage unit 30 as the second reference value (distance determined to be close). Note that the distance determined to be close is not limited to 50 mm or less, and can be changed according to the use conditions of the mobile phone 41, and may be, for example, 20 mm or less.

  In addition, when the optical device detects human skin or hair, and further detects that the detected human skin or hair is close to (including contact with) the screen with the touch panel function, the optical device A signal indicating that they are close to each other is output, and the touch panel function is switched off.

  According to the mobile phone of this embodiment, since such a configuration is provided, it is possible to prevent the screen with a touch panel function from malfunctioning during a call.

  In the present invention, the embodiment of the electronic device is not limited to the mobile phone described above. For example, the above-described optical device may be mounted on an AV (audio-visual) device, an OA (office automation) device, or a sanitary device. In this case, since the proximity of the detection object can be detected, malfunction of the electronic device can be prevented.

  The optical device of the present invention, the object detection method using the optical device, and the electronic apparatus can be utilized when downsizing or improving detection accuracy.

1,101 Substrate 2,102 Infrared LED
3 CMOS image sensor 4, 104 Light-shielding part 5, 105 Mold part 5a, 5b Lens part 10 Proximity sensor 11, 11a, 11b Detected object 20 Signal processing part 30 Database storage part

Claims (5)

An optical device for detecting the object as a detection target in order to prevent malfunction of the mobile communication terminal caused by the proximity or contact of the object with the input / output screen of the mobile communication terminal in a communication state,
A light emitting element that emits infrared light, a light receiving element that receives reflected light from an object detected by the infrared light, and outputs a signal indicating a light amount and an incident position of the reflected light, and is output from the light receiving element A signal processing unit that amplifies the signal and performs signal processing ;
It is determined that the data indicating the relationship between the detected object distance and the amount of received light for each reflectance stored in the database storage unit and the data indicating the first reference value that is the reflectance of the detection target are close to each other. The signal processing unit that performs signal processing using data indicating a second reference value that is a distance includes first signal processing that calculates a detected object distance based on the incident position, the calculated detected object distance, and the Second signal processing for determining the reflectance of the detected object by comparing the amount of reflected light with data indicating the relationship between the detected object distance and the amount of received light for each reflectance, and the obtained reflectance is the first reference value Third signal processing for determining whether or not the second reference value matches with the first reference value, and fourth signal processing for determining whether or not the calculated detected object distance matches the second reference value. If it matches the second reference value, it means that the object to be detected is close Optical device for implementing the fifth signal processing for outputting to the signal. The optical device according to claim 1, comprising:
The light emitting element is an infrared LED, the light receiving element is a CMOS image sensor, the infrared LED and the CMOS image sensor are mounted on the same substrate, sealed by a resin mold portion, and the infrared An optical device in which an LED and a CMOS image sensor are shielded from light by a light shielding portion. The optical device according to claim 1 or 2,
An optical device in which the wavelength of the infrared light is 940 nm, the first reference value is 0.1 or less and 0.2 to 0.4, and the second reference value is 50 mm or less. An object detection method using an optical device for detecting an object as a detection target in order to prevent malfunction of the portable communication terminal caused by the proximity or contact of the object with the input / output screen of the portable communication terminal in a communication state Because
A light emitting element that emits infrared light, a light receiving element that receives reflected light from an object detected by the infrared light, and outputs a signal indicating a light amount and an incident position of the reflected light, and is output from the light receiving element Using an optical device consisting of a signal processing unit that amplifies the signal and performs signal processing ,
The optical device is a distance determined to be close to data indicating a relationship between a detected object distance and a received light amount for each reflectance, and data indicating a first reference value which is a reflectance of the detection target. A database storage unit storing data indicating a second reference value;
The signal processing performed by the signal processing unit includes first signal processing for calculating a detected object distance based on the incident position, the calculated detected object distance and the amount of reflected light, and the detected object distance and received light amount. Second signal processing for determining the reflectance of the detected object in comparison with data indicating the relationship between the first and second objects, third signal processing for determining whether or not the determined reflectance matches the first reference value, In the case where it matches the reference value, the fourth signal processing for determining whether or not the calculated detected object distance matches the second reference value, and in the case where it matches the second reference value, the detection object is close. And a fifth signal processing for outputting a signal indicating that.   An electronic apparatus comprising the optical device according to claim 1, 2 or 3 mounted thereon.

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